DEPARTMENT OF THE INTERIOR

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTJS SMITH, DIRECTOR

382

THE EFFECT OF OXYGEN IN

COAL

BY

DAVID WHITE

WASHINGTON

GOVERNMENT FEINTING OFFICE

1909

CONTENTS.

Page.

Introduction.............................................................. 5

Deoxygenation in the formation of coal..................................... 6

Initial controlling factors............................................... 6

Stages of formation.................................................... 6

Deoxygenation.......................................................... 7

Oxygen rind ash as impurities.............................................. 8

 Evic ence of their nearly equal value................................... 8

Calorimeter tests................................................... 8

Ultimate analyses................................................. 9

Arrangement of analyses............................................ 19

Fuels high in oxygen or ash........................................ 19

.Fuels of lower' ash and oxygen..................................... 20

Belation to calorific value.........................'................ 21

Cur\ e platted from C : (0+ash) ratios and efficiencies.................... 22

Determination of curve............................................. 22

Detailed study of a curve segment................................... 22

Variations from the curve.......................................... 23

Comparison with calculated thermal units........................... 24

Forecast of fuel efficiency from ratios............................... 24

Relations in moisture-free coals........................................ 25

Recalculation of analyses........................................... 25

Compensated calorific values....................................... 34

Value of moisture-free data.....................:.................... 35

Relative negative value of ash and oxygen............................... 36

Relative effect of the oxygen of moisture................................ 37

Estimate of the empirical anticalorific value of oxygen................... 39

Negative value of oxygen and ash.................................... 39

Application of the curve........................................... 39

 Fluctuation in effects of changes.............'....................... 40

Estimate applied to the analyses................................... 40

Causes of variance from the curve...................................... 41

General statement.................................................. 41

Causes not shown by ultimate analyses.............................. 41

' Causes recognizable in analyses...................................... 42

Varying available hydrogen.................................... 43

Sulphur....................................................... 44

Nitrogen............'.......................................... 46

Anthracitization............................................... 46

Weathering................................................... 48

Quantitative relation of oxygen to coking.................................... 48

Supposed algal ingredients in coals..............................:....... 48

i'5ource and chemical effects........................................ 48

Characteristics of algal coals......................................... 50

Possible connection with coking quality............................ 50

3
4 CONTENTS.

Quantitative relation of oxygen to coking Continued. Page.

Hydrogen-oxygen ratios of coking coals................................. 51

Description of diagram in Plate III.......................:.......... 51.

Indications of ratio limits........................................... 52

Application to algal hypothesis..................................... 53

Coking of high fixed carbon coals....................................... 53

Volatile-carbon ratios.............................................. 53

Consultation of efficiency errors..................................... 54

Hydrogen and oxygen losses in the progressive development of coal....... 54

Available hydrogen as index of coking coals.............................. 55

Hydrogen-oxygen ratio the best index............................;...... 56

Status of algal hypothesis.............................................. 56

Mixture of coals for coking.............................................. 57

General observations on the tabulated coals.................................. 58

Range of the samples................................................... 58

Rank of peats and lignites............................................. 58

Explanation of high oxygen............................................. 59

Quantitative relation of volatile carbon and hydrogen..................... 59

Loss of volatile matter.................................................. 60

Relation of stage of coal formation to classification ........................... 60

Like analyses for coals of different origin.................'................ 60

Distinct categories impossible.......................................... 61

Comparison of types.................................................... 61

Obliteration of distinctions as a result of regional metamorphism.......... 62

Oxygenation and weathering of coals........................................ 63

Changes in low-grade coals.............................................. 63

Efficiency losses in weathering.......................................... 63

Losses shown by analyses and ratio-efficiency curve...................... 64

Losses shown by H : 0 and VC : C ratios................................. 65

Underground weathering................................................ 67

Losses by weathering in shipment...................................... 69

Summary.................................................................. 70

Partial bibliography....................................................... 73

Index.................................................................... 75

ILLUSTRATIONS.

Fage. 

PLATE I. Ratio-efficiency curve of coals tabulated..........................'. 22

II. Segment of ratio-efficiency curve................................... 22

III. Diagram showing hydrogen-oxygen ratios of coals................... 52
THE EFFECT OF OXYGEN IN COAL.

By DAVID WHITE.

INTRODUCTION.

This paper is the result of a comparative study of ultimate coal 

analyses made and published by the United States Geological Survey.

This study, at first casually undertaken to devise an acceptable 

classification of coals based on chemical analyses, was continued in 

connection with a microscopic examination of a number of the coals. 

The initial comparisons, made from a relatively small number of 

analyses, not only confirmed a previous conviction that the elimination of oxygen incident to the development of a coal is economically 

far more important than has been generally suspected, but also showed 

that oxygen is very nearly as harmful as ash in coal.

The immediate purposes of the present study were: (a) To determine more definitely, from a comparative examination of a large 

number of ultimate analyses, the relative importance of oxygen as 

an impurity in various coals; (&) to illustrate the transition between 

various grades of coal of similar origin transition mainly due to 

progressive devolatilization, brought about more or less directly by 

dynamic influences; (c) to ascertain the relative proportions of 

oxygen, hydrogen, and carbon in coking coals, especially with reference to a theory tentatively framed to explain the coking quality; 

and (d) to forecast the probabilities of successfully treating a large 

number of coals so as to render them amenable, in a softened condition, 

to satisfactory study under the microscope.

Although the hypothesis as to coking quality finds but partial 

support in the chemical analyses, its consideration has led to a method 

of predicting from an analysis with a fair degree of certainty whether 

any given coal will coke by the ordinary process. The unbroken 

transition between coals originally similar but now classed in widely 

different groups, whether of the same age or of different ages, as 

a result of dynamochemical action, appears demonstrated by the 

analyses as well as by field observation. This subject will not be

5
6 THE EFFECT OF OXYGEN IN COAL.

specially discussed in this paper, though the tables offer forcible, if not 

convincing, evidence concerning it.

The great number of ultimate analyses published by the Survey, 

covering samples of coals of so many sorts collected throughout the 

wide range of American coal fields, furnishes an unrivaled wealth of 

analytical data concerning the fuels of the country; and the fact 

that all are made under one highly expert direction, and are standardized, renders them especially valuable for comparative study.

The discussion of chemical changes that have occurred in the coals 

and of the nature of the compounds now existing in them is left to 

the professional chemist, who is familiar with the great mass of literature concerning the chemistry of coals.

Acknowledgments are gratefully tendered to Messrs. M. R. Campbell and J. S. Burrows for placing at my disposal many of their 

recalculations of the analyses from the "as received'' to the "airdried" basis and thus greatly lightening the labors of computation; 

also to Mr. Burrows for annotations as to the coking qualities of the 

coals. Thanks are also due to Mr. Wirt Tassin, of the National 

Museum, for frequent and generous gifts of information and counsel.

DEOXYGENATION IN THE FORMATION OF COAL.

INITIAL CONTROLLING FACTORS.

The great variation in kinds and qualities of coal is due to differences, many of them of wide range, in the consecutive influence or 

operation of three controlling and indispensable factors; that is, to 

differences (1) in the kinds and sources of the original ingredient 

matter; (2) in the conditions of accumulation and deposition of this 

matter; and (3) in the phase and stage of progress of the coal-forming 

process the transformation of the organic matter into coals of various 

grades. The comparative importance of each of these cooperative and 

mutually related factors varies from coal to coal, and it is necessary 

to bear in mind that they combine not only in complex but also in 

constantly changing phases and efficiencies, so that their products, 

though often similar, are never exactly the same. It is to the third 

of these factors that the following discussion for the most part relates.

STAGES OF FORMATION.

When the organic matter, chiefly of various vegetal types, accumulates under conditions favorable for the formation of coal, the process 

of conversion goes forward. In the ordinary course of events this 

process embraces two fundamentally important stages:
DEOXYGENATION IN FORMATION OF COAL. 7

1. The putrefaction or fermentation stage, in which the action is 

essentially biochemical.

2. The stage of chemical and physical alteration, which is mainly 

induced and controlled by dynamic geologic influences, and in which 

the action may therefore, in contrast, be termed dynamochemical.

These two stages are practically consecutive, though slightly overlapping; and, on account of conditions that will readily be conceived 

and need not be discussed here,0 the intensity and extent of the 

operation or progress of each stage varies greatly. .The physical 

characters and qualities of the younger and less mature coals, including lignites and peats, are largely determined by the relative progress 

of the biochemical action, the most evident visible effect of which is 

the disintegration of the organic structures, usually accompanied by 

darkening of the color. On the other hand, the further progressive 

devolatilization, as well as the lithification, dehydration, and metamorphism of the coals, characterize the dynamochemical stage. The

biochemical action, essentially the work of anaerobic bacteria, is, 

geologically speaking, relatively soon terminated, even when it progresses to a point just short of complete destruction of the original 

organism; the succeeding work, under the influence of geodynamic 

agencies, is still in progress, the ultimate goal being the practically 

complete devolatilization of the coal and its transformation into 

graphite.

DEOXYGENATION.

In all the chemical changes marking both stages in the conversion 

of organic debris into coal, the preeminently important result to man 

is elimination of oxygen. Economically this is the most essential 

incident of the process. From a beginning with over 40 per cent of 

oxygen, in the cellulose and lignose of the woody matter, which comprises so great a part of the organic substance actually entering into 

coal formation, to the present nearly devolatilized state of an anthracite, with less than 2.5 per cent of oxgyen, deoxygenation has progressed continuously, though at varying rates, in every unweathered 

coal. As the original oxygen is more and more nearly eliminated, the 

heat efficiency of the coal increases. In other words, with respect to 

their efficiency as fuels, oxygen is an original impurity in coals, which 

improve according to the extent of its removal. It will be shown 

later that the deleterious effect of oxygen in coals greatly exceeds the 

common conception of it, being nearly equal to that of the same 

weight in ash. The negative importance of oxygen seems to be 

little realized outside of the ranks of coal analysts.

a See Econ. Geology, vol. 3,1908, p. 292.
8 THE EFFECT OF OXYGEN IN COAL.

OXYGEN AND ASH AS IMPURITIES.

EVIDENCE OF THEIR NEARLY EQUAL VALUE.

CALOKIMETER, TESTS.

At a conference held in Washington, March, 1907, for the purpose 

of discussing the classification of coals, I urged that a classification 

based on chemical composition, to be satisfactory for either technical 

or practical purposes, should give careful heed to the oxygen content, 

for the degree of deoxygenation would be found to be most intimately 

connected with the relative efficiency of the fuels. By using the 

limited number of ultimate analyses then made public by the fueltesting plant of the United States Geological Survey as a basis of 

illustration, it was shown that, among coals of equal ash, the ascertained calorific values of the air-dried samples corresponded closely 

to the order of the ratios of the total carbon to the oxygen C (C : 0). 

The number of ultimate analyses showing approximately equal ash 

was, however, so small as to be inconclusive. I therefore attempted, 

by means of a critical comparison of all the analyses, to discover a 

coefficient for use in compensating for the highly variable ash content. From this study it was noted that, in general, so far as shown 

in the calorimeter, the deleterious effects of oxygen and of ash in the 

coals represented in the list were practically of very nearly equal 

importance. For example, the calorimeter tests seemed to show that 

two coals having the same carbon content, but with reverse proportions of ash and oxygen (one with 15 per cent ash and 4 per cent 

oxygen and the other with 4 per cent ash and 15 per cent oxygen) 

have nearly the same heat efficiency. In other words, oxygen and 

ash appear to be of nearly equal negative or anticalorific values.

The fact having been noted that the coals with constant ash 

arrange themselves as to efficiency largely in the order of the ratios of 

carbon to oxygen, it. at once became evident, oxygen and ash being 

of equal negative calorific effect, (1) that coals with constant oxygen 

should also similarly rank not far from the order of their carbon-ash 

ratios; and (2) that the efficiencies of coals in which both oxygen and 

ash vary should correspond nearly equally well to the relative order 

of the ratios of the carbon to oxygen plus ash. Examination of a 

more extended series of analyses confirms the conclusions based on 

the original list.

In these comparative studies the contribution of the hydrogen of 

the coal to the heat value is assumed to be nearly constant; hence 

the hydrogen is ignored temporarily, as also are the sulphur and the 

nitrogen. The main purpose is to show that in a miscellaneous 

series of coals of all grades those with high oxygen content will, in 

general, have approximately the same calorific value as those with
OXYGEN AND ASH AS IMPURITIES. 9

equally high ash if the C: (0 + ash) ratios are the same; or, in other 

words, that, taking coals as they run, oxygen and ash are, according 

to the calorimetric tests, to be regarded as equally undesirable.

ULTIMATE ANALYSES.

To illustrate somewhat graphically the approximate equality of the 

anticalorific values of these two great impurities in coal, while at the 

same time showing the relatively close correspondence of the calorific 

values to tiie sequence of the ratios C : (0 + ash), Table 1 (pp. 11-18) 

has been compiled showing a series of over 300 ultimate analyses of 

air-dried samples of fuels. All these analyses were made in the laboratories of the United States Geological Survey.

As first compiled the table included all the ultimate coal analyses 

which, in December, 1907, had come to hancl. By mere coincidence 

they numbered 250. Nearly 70 additional analyses of samples by 

the geologists working in the various coal areas have since beer, 

intercalated. These intercalations, many of which represent weathered material, have alphabetic designations affixed to the numbers, 

thus retaining the original series of numbers for the mined coals 

especially investigated by the Survey.

The air-dried coal samples, according to the later practice of the 

chemical laboratory, are those that, after pulverization, were dried 

in a special oven in a gentle current of air 10° to 20° above the 

temperature of the laboratory.0 In the. earlier laboratory work the 

samples were crushed fine, spread out on shallow trays, and dried in 

the air of the laboratory for twenty-four to ninety-six hours, or until 

the loss between two successive weighings (made twelve to twentyfour hours apart) was small, usually less than 1 per cent. 6

All but one of the analyses will be found in Professional Paper 48, 

or in Bulletins 260, 261, 290, 316, or 332 of the United States Geological Survey. Most of the recalculations of the analyses and computations of ratios in this paper were done without the aid of the computing machine and are subject to correction. For original forms, 

including "as received" and "dry coal" recalculations, the reader is 

referred to the papers here mentioned.

It will be observed that the coals here listed represent most of the 

American coal fields. They come from 27 States and Territories. 

One is from Batan Island and one from Mexico. In age they range 

from basal Mississippian (Pocono) to Recent. The post-Paleozoic 

coals belong to the Kootenai (basal Cretaceous); Bentori, Eagle, 

Mesaverde, and Laramie (Upper Cretaceous); "Upper Laramie, ;; 

Fort Union, Bridger, and Gulf Coast Eocene; Pacific Coast Miocene;

a For description of this process see Bull. U. S. Geol. Survey No. 290, 1900, pp. 29-30. 

b See Prof. Paper U. S. Geol. Survey No. 48,1906, p. 177. For comparison of results see Bull. U. S. Geol. 

Survey No. 323, p. 8.
10 THE EFFECT OF OXYGEN IN COAL.

and Atlantic Coast post-Pleistocene. In, kinds they embrace peats 

and xyloid and earthy lignites (brown coals), as well'as subbituminous, bituminous (dry and coking), semibituniinous, semianthracite, 

anthracite, and graphitic coals. In order not to omit any ultimate 

analysis of a coal investigated by the Survey, so far as they had come 

to hand up to the close of 1907, the semigraphite from Providence is 

also included. The graphitization of this highly metamorphic 

Carboniferous coal is so nearly complete that, although a coal from 

the genetic standpoint, it can not be regarded as a fuej, for it is 

practically incombustible unless chemically treated. It is used 

mainly for foundry facing. The lower-class coals are distinguished 

in accordance with the simple and very practical system recently 

.proposed by M. R. Campbell.0 This classification, based on weathering and salient physical characters, is briefly as follows:

Bituminous coals, except cannel and block (which are recognized 

by special well-known criteria), are more thoroughly jointed, and in 

weathering split generally in agreement with preexisting cleavage, 

the particles remaining prismatic even when very minute.

Subbituminous coals are black, generally less jointed, and have 

poor cleavage, which shows only in the larger blocks. On exposure 

to the atmosphere the lumps check irregularly, the resultant fragments, however small, being irregular in outline and having rough 

faces instead of cleavage planes. Weathering is characterized (very 

conspicuously in the longer exposed fragments) by separation of the 

coal in plates parallel to the bedding, this process continuing to 

invisible limits.

Lignites are distinguished from subbituminous coals only by their 

brown, instead of black, color and generally woody aspect. They 

are the "brown coals."

The higher grade coals are provisionally grouped as proposed by 

Prof. F.F.-Grout.6 .

It will be noted that the samples analyzed are not always marketable coal; in many cases they, represent fine coal, screenings, refuse, 

slack, dust (culm), waste and " bone." The low position of a number 

of the high-grade coals for example, No. 30 (W. Va. 24) from the 

famous Pocahontas bed is accounted for by the great amount of 

ash in the bony layer from which the sample was taken.

o Econ. Geology, vol. 3,1908, p. 134. & Op. cit., vol. 2,1907, p. 240.
TABLE ]. Ultimate analyses of 319 American coals, "air-dried" basis, from the chemical 

value and C: (0-\-ash) tatio of each coa

No

1

9,

?a

?h

3

4'

4a

5

fi

7

8

9

Qn

10

11

1'a

13

14

Ifi

17 

IS

19

?0

?1

?3

?4

25

?fi

?S

28a 

29

30

O1

31 a

Designation of

coal.

Mass. 1........

N. Dak. IB...

Mont. 3701 ....

Wyo. 3694.....

N. Dak. 3.....

Ark. 10........

Mont. 3816....

N. Dak. 2B...

Fla.l. ........

Tex.l.........

N. Dak. 1.....

Wyo. 3........

Wyo. 3S92.....

Ind. T. 5......

Cal.l.. .......

Mo.7C .......

Wyo. 2326.....

N.Dak.2......

111.2..........

Mo. 7 A .......

Mo. 3.........

N. Mex. 2..... 

Wyo. 2........

Wyo. 2B .....

Mo. 10........

Tex. 3........

Wyo. 1 ........

I11.7A ........

Mo. 7B .......

Colo. 3S56 ......

W. Va. 24.....

Colo. 3729.....

Halifax........ .

Lehigh...............

Wilton...............

Williston.............

Lehigh...............

Aladdin..............

Lehigh. .......... .

Williston.............

 Gallup... ............

Hoyt.................

Near Thompson's.....

Gary.................

Carbonera... .........

Kind.

P.

L.

S.

S.

L.

L.

L.

L.

P.

L.

L.

B.?

S.

B.

B.

S.

L.

B.

B.

B.

S. 

B.

L.

B.

B.

L.

B.

L.

S.

B.

B.

B.

B.

B.

S.

Sb.

S.

B.

N.

1.40

.55

.65

.85

1 3Q

91

.65'

.88

2.56

QC

.71

.72

i 4ft

1 99

70

98

00

91

.78

1.01

.92

.98 

.80

1.06

OC

1.02

Q7

97

1 IS

1 09

.65

QQ

1 13

1 H9

1.35 

1.14

.66

1.36

1.30

S.

0.58

3.95

.66

.65

1.55

.49

1 f\d

6.86

2 

OC

4.06

3 4n

3 47

4.78

.63

4 30

3.45

4 1 P.

1.30 

4.17

4 2°

Qfi

.70

4.28

1 30

.63

1.71

99

4 1 7

.60 

.62

.55

.76

.50

H.

.5.55

5.57

4.51

4 

AC

5. 88

5

ftO

5.66

5.57

5 99

5

nq

4.70

4 1 R

c 09

3

QC

4.86

5.61

4

C7

4.65

4 

co

5.05 

4 54

C OO

4 59

3 Q7

5.06

4 05

5 1 9.

6.09

4.17

4 71

3.96

4. 9°.

4.86

4

7C

3

00

=, 9 =

5.37

C.

40.78

48.01

48.65

48.51

AQ CC

en 7Q

52.06

52.66

co CQ

CO qn

59 Q.°.

CO CC

co co

54 06

54.30

K.A 7Q

56.71

CC 9Q

57.31

55.84

58.97

CO OO

CO XO

58.41

59.65

^7 4^1

57.82

60.49

an Q7

60.41

61.17

O.

30.95

oq A7

28.17

OQ C7

35.08

31.36

ox 91

2

C CO

90 79

10.48

i o An

on no

12 13

1 A. 9°.

16.74

19 Q4.

1 9 79

6.36

24 48

9 69

90 fiC

28 99

i c i n

14.00

4.90

8.98

13.23 

16.60

3 Q7

20.00

16.58

Ash.

20.74

12.75

18.00

6.87

8.88

12.97

9 41 

6.10

5.68

14.85

17.20

25.75

17 29

17.35

6.71

24.16

23.30

19.22

9.81

9Q "^

9 96

OO 7A

10.30

4.79

18.63

18.22

28.53

19.47

1 C Q9

28.77

U O9

15.08

C

O+ash.

0.79

96

1.04

1.07

1.09

1.11

1.21

1.28

1 29

1.31

1.31

1

0ft

1.37

1.41

1.41

1.42

1.46

1.48

1.48

1.56

1.57 

1.57

1 60

1.63

1.71

1.71

1.72-

1.73

1.76

1.78

1.81

1.81

1.85 

1.87

1.90

1 no

1.93

Calories.

4,055

4,714

4,961

5,199

5,034

5,108

65,106

5,201

5

97C

5 O.QQ

5,273

5,506

5,668 

5,758

5

e/\9

5,815

5 Q9O

5,682

5,857

5,753

5,824

5,863

5,836

5,853

6,029 

6,020

5

QCQ

6.089

Moisture.

13.60

24.82

15.12

10.88

26.64

19.13

22.77

13.19

13.40

12.58

1 ft °.9

5.74

9

f\K

7.21

16.73

5.31

7.41

5.51

8.13 

2.73

10.66

4

(\A

91

9 7R

1.77

9.SS

17.69

6. SO

1.26

2.17

4.14

^ °.Q

.52

9

0 =

6.76

o Coals more or less weathered. & From 
TABLE 1. Ultimate analyses of 319 American coals, "air-dried" basis, from, the chemical 

value and C :(0-\-ash) ratio of each coal Con

No.

32 

33 

33a 

34 

35 

36 

37 

38 

39 

39a 

39b

40 

41 

42 

43 

44 

44a 

44b 

45 

46

46a

47 

48 

49 

50

51 

51a

52 

52a 

52b 

52c 

53 

53a 

54 

55 

55a

Designation of 

coal.

Colo. 1 ........

111. 24A ....... 

N. Mex. 3811 . . 

Ind. 20...--...

Ark. 9........

Mont. 3.......

111.27.........

111.4..........

Wyo. 3699..... 

Wyo. 3780.....

Ind. 3.........

111.8..........

Mo. 1.........

111.6..........

Wyo. 3693..... 

Mont. 3515.... 

111. 23A.......

Wash. 1. ......

Colo. 4050..... 

111. 21B.......

Iowa 2........ 

111. 7B........

Wash. IB ..... 

Ind. 1.........

 Philip........

N. Mex. 3952.. 

Wyo. 2325..... 

Colo. 3463..... 

111. 25B.......

Wyo. 3917..... 

111. 9C. ........

111. 22A .......

Wvo. 3698.....

Locality.

Livingston. .......... 

West of Putnam. .....

Troy.................

Northeast of Hanna. . .

Near Glen wood 

Springs. 

Troy.......... .......

Hamilton. ...........

Mildred ...._...'......

Lay..................

Near Fort Steele. ....

Labaree Ranee .......

Kind.

S. 

B. 

S. 

B. 

Sb. 

B. 

S. 

B. 

B. 

S. 

S.

B.

S. 

B. 

B. 

B.

S. 

B. 

B.

S.

B.

B. 

B. 

B.

S.

B.

S.

B. 

B.

S. 

B. 

B. 

S. 

B. 

B. 

S.

N.

1.22 

.97 

1.51 

1.16 

1.28 

1.22 

1.09 

1.01 

1.17 

1.09 

1.73

1.18 

.90 

1.08 

.99 

1.23 

1.03 

.69 

1.04 

1.30

1.58

1.24 

1.46 

1.03 

1.29

1.22 

1.33

.94 

1.03 

1.23 

1.16 

1.12 

1.56 

.95 

1.06. 

1.08

S.

.58 

4. 56 

1. 92 

2. 17 

1.04 

3. 42 

.56 

4.50 

1.34 

1. 14 

2.41

5.24

.29 

4.68 

5.53 

4. 45 

2. 10 

3. 80 

4.58 

.68

.98

1.17 

5.20 

4.69 

.80

2.58 

1.36

4.46 

1.54 

.22 

1.05 

5.06 

.85 

4.39 

5.68 

.84

H.

5.75 

4.71 

5.50 

4.63 

3.59 

5.35 

4.87 

4.93 

5.33 

5.39 

5.73

4.83 

5.42 

5.25 

4.64 

4.88 

5.74 

4.02 

4.55 

4.91

5.04

5.14 

4.84 

5.14 

5.16

5.20 

5. 55

5.31 

5.45 

4.97 

5.50 

5.05 

5.16 

4.31 

4.83 

5.68

C.

61.13 

59.37 

60.32 

60.96 

62.49 

59.89 

62.32 

59.88 

61.79 

62.05 

60.53

59.58 

62.68 

59.88 

60.00 

60.51 

61.76 

62.51 

60.93 

63.28

62.74

62.84 

60.36 

60.71 

63.35

62.20 

62.91

61.25 

63.00 

64.28 

63.43 

60.96 

63.57 

62.23 

60.94 

63.81

0.

24.95 

12.88 

20.61 

11.09 

5.70 

16.57 

17.34 

14.38 

18.32 

24.56 

23.55

12.09 

23.23 

16. 01 

8.46 

14.20 

25.96 

9.16 

10.94 

16.92

19.71

17.26 

11.15 

14.77 

16.82

14.99 

23.29

16.56 

12.36 

21.56 

22.37 

13.57 

25.05 

10.41 

13.66 

25.75

Ash.

6.32 

17.51 

10.14 

19.99 

25.90 

13.55 

13.82 

15.30 

11.85 

5.77 

6.05

17.08 

7.48 

13.10 

20.38 

14.73 

3.41 

19.82 

17. 96 

12.91

9.95

12.35 

16.99 

13.60 

12.58

13.81 

5.56

11.48 

16.62 

7.73 

6.49 

14.24 

3.80 

17.71 

13.83 

2.84

C

O+ash

1.95 

1.95 

1.96 

1.96 

1.97 

1.98 

2.00 

2.01 

2.03 

2.04 

2.04

2.04 

2.04 

2.06 

2.08 

2.09 

2.10 

2.11 

2.11 

2.12

2.12

"2.12 

2.14 

2.14 

2.15

2.16 

2.17

2.18 

2.18 

2.19 

2.19 

2.19 

2.20 

2.21 

2.21 

2.23

Calories.

5,995 

6,068 

5,994 

6,089 

6,067 

6,105 

6,126 

6,135 

6,106 

06, 039 

66,040

6,090 

6,116 

6,110 

6,191 

6,199 

"6,057 

6,094 

6,180 

6,182

6,226

6,278 

6,212 

6.229 

6,273

6,336 

<=6, 101

6,237 

6,500 

6,220 

6,198 

6,337 

6,310 

6,273 

6,267 

a6.258

Moisture.

13.49 

4.92 

8.86 

4.38 

1.11 

9.22 

5.63 

6.67 

11.40 

9.02 

10.12

5.12 

9.21 

9.21 

3.50 

5.13 

10.78 

1.93 

2.86 

5.98

7.05

8.52 

4.25 

7.60 

5.20

8.66 

7.06

10.03 

4.01 

7.73 

9.87 

5.79 

8.70 

2.25 

6.39 

10.22
56

57

CTo

58

59

60

61

6?

6?a

63

64

65

66

66a

67

68

69

70

71

7?

7?a

73

73a

73b

7.V

74

75

75a 

75h

76 

77

78

79

80

81

81a

82

S3

R4

R4a

85

86

87

88

89

90

91

92

111. 29B .......

111. 6B ........

111.29.........

HI. 1.. ........

111.15.........

Utah 40 13.....

Ind. 13........

111.30.........

111.21.........

111. 22B .......

Ind. T. 4......

111.31.........

Mont. 4115....

Wyo. 2283.....

Ind. 2.........

Ind. 17........

Colo. 3462.....

111.14.........

111.12.........

Ind. 6. ........

I11/9A........

Ariz. 4112..... 

111.26.........

111. 19E .......

Colo. 3703.....

Ala. 2B.......

N.Mex. 3A...

Ind. 16........

Mo. 5.........

Ohio2. .......

Yale..................

Book Cliff aeld.......

Lay..................

Springfield ...........

Yale..................

Near St. Michaels .....

Carbon Hill. .........

Superior. .............

S.

B.

S.

B.

B.

B.

B.

B.

B.

B.

S.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

S.

B.

B.

B. 

B.

B. 

B.

B.

B.

B.

B.

B. 

B.

S.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

.88

.85

1 OQ

1.10

1.08

97

1.07

1.09

i °.n

.93

1.05

1.11

97

1.26

.87

1.03

1.22

1.38

1.47

1.14

1.13

.92

1.03

1.25

94

1.22 

1.40

1.19 

1.28

.94

1.19

i (\d

1.28 

1.21

1.10

1.53

1.12

1.52

1. 25

1.13

1.26

1.02

1.25

1.25

.27

4.68

.50

4.67

4.71

4.25

4.04

6.83

.64

5.03

.76

3.37

2.59

4.80

1.55

4 90

4.02

.66

4.05

.89

2.43

.58

4.60

1.14 

.54

452 

1. SS

6.40

4.63

4.43

.42 

4.02

.54

.60

1.14

.74

4.50

4.00

.78

5.68

4.13

4.17

6.18

5.11

5.41

4.69

4.92

3 no

4.99

4.71

4.93

4.26

4 99

5.20

5.25

4.92

4.94

4.83

4.33

c 94.

5.11

5 

no

5.53 

5.24

5.00 

5.05

4

OC

5.15

5.75 

4.75

4.54

5.20

4.46

5.02

4.69

5.01

5.17

64.01

64 07

61.96

61.67

61.80

62.01

62.25

64.88

60.62

62.65

63.39

62.60

64.76

CO QQ

63.47

65.51

62.97

63.70

65.33 

66.12

63.85 

65.62

64.85

63.14

64.22

64 49

66.81 

65. 02

67.48

67.42

67. 35

67.54

64.82

67.76

64.52

6-5.28

65.14

21.62

14. 62 -

91 fiS

12. 15 '

14.07

10.90

13.82

11.16

21.14

5.13

20.41

14.31

12.20

15.34

20.96

11.84

I9 66

1 A. R7

20.41

12.64

19 11

6.69

11.50

13.06

21.69 

11.15

14.99

22.64

10.69

8.63

12.04

7.75

8 79

11. SS

12.51

7.04

13.05

7.14

15.43

16.52

13.72

13.81

8.53

15.53

7.10

21.82

7.42

12.81

16.05

12.20

16.36

6.28

14.67

14.49

3.43

13.51

11.61

6.37 

4.78

12.80

13.43

13.31

11.80

4.05 

13.85

3.52

10.92

3.02

14.84

12.49

16.92

19.47

15.37

11.76

2.23

2.23

2.23

2.24

2.24

2.25

2.25

2.25

2.26

2.27

2.28

2.32

2.33

2.33

2.34

2.35

'2.35

2.38

2

0Q

2.39

2.39

2.40

2.40

2.41

2.41

2.44 

2.48

2.50 

2.51

2

K.A

2.54

2.58

2.59 

2.60

2.61

2.62

2.63

2.63

2.64

2.66

2.66

2.67

2.68

2.68

6,183

6,302

6.420

6,229

6,393

6,329

6,360

6,356

6,293

6,309

6,353

6,329

6,430

6,446

6,414

6,426

6,510

6,514

6,327

6,394

6,532

6,348

6,410

66, 419 

6, 534

6,496 

6,519

6,548

6,600

6,555

6,538

6,723 

6,579

<*6,456

6,625

6,654

6,660

6,742

6,623

6,663

6,693

6,614

6,688

6,625

8.94

7.14

8.07

4.17

5.58

5.21

6.28

6.00

5.12

4.52

10.86

1.51

4.34

7.18

7.62

3.58

3.27

5.74

2.06

4.91

10.00

3.77

6.17

3.70

7.57

6.24

7.36

8.66 

8.91

5.13 

6.24

2.23

5.91

4.99

9.89 

3.41

8.68

5.27

8.67

2.29

1.48

4.68

2.09

1.03

1.7

4.4

5.6

a From shallow mine or country bank. 6 Coals more or less weathered. 
TABLE 1. Ultimate analyses of 319 American coals, "air-dried" basis, from the chemical 

value and C: (0+ash) ratio of each coal C

No

93

94

95

96

97

98

99

100

101

lOla

102

103

104

105

106

107

108

109

110

HOa

111

112

112a

113

114

115

116

118

119

120

122

124

125

127

Designation of

coal.

N.Mex. 3B...

111. 23B .......

I11.19C........

111. 24A.. ......

111.3..........

Ind. 5.........

I11.9B.........

N.Mex. 30....

Ind. 11. .......

Ind. 9.........

Ind.lSB......

I11.34B.......

Ohio 1 ........

111.19.........

Ind. 9B .......

Ky. 4. ........

111.10.........

Wyo. 3891.....

Ky.3. ........

111. 12B.......

Wyo. 3509.....

Mo. 6.........

Ala. 2.........

Ind. T. 8......

111.120........

Ind. 8.. .......

N.Mex. 4B...

111. 11B.......

111.18.........

A In ^

111.13.....:...

Ark. IB.......

111.280........

Ind. T. 2B....

N Mex 4A

111. 12D.......

tain.

Fort Steele ..........

(?)..................

Brilliant..........)-..

Bush................

Kind.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

-B.

B.

B.

Sb.

B.

B.

B.

B.

N.

1.22

1.03

1.49

1.10

1.43

1.16

1.09

1.20

1.44

1.26

1.12

1.18

1.38

1.48

1.19

1.12

1.46

1.38

1.43

1.02

1.79

1 08

1.55

1.64

1 19

i is

1.53

1.37

1 09

i 33

1.55

1.46

1.25

1.72

1.53

1.22

S.

.86

4.68

.54

5.33

1.77

4.60

4.40

.65

1.47

.63

3.56

1 49

2.96

4

QC

.57

3.53

4.67

3

c;<;

1.56

.33

3.60

2.60

.88

6.34

1 93

2

c e

S on

.62

4 28

1.46

1.62

1.88

.62

2.70

H.

4.60

4.91

5.10

4.94

4.92

5:07

5.14

4.75

5.22

5.19

5.19

5.50

4.69

5.12

5.14

4

EO

4 80

4.88

5.31

5.27

5.17

4.79

4.67

4 

oo

4 97

4.88

S

OT

4.90

3.86

4.88

4.51

5 

no

4.75

0.

68.00

65.10

67.91

64.86

67.30

65.44

65.57

68.66

67.63

68.46

66. 48

67.95

67.29

65.70

69.05

66.79

66.50

67.31

68.56

69.07

66.75

68.30

68.93

69.24

68.65

68.36

69.48

68.25

66.91

69 64

69.00

70.25

69. 54 

69.15

69.86

68.81

O.

8.91

10.95

13.53

12.20

1' 99

12.32

9 00

15.76

13.25

12.46

16.80

10.59

8

y|O

10.58

18.99

12.66

17.24

8.85

10.87

8.86

11.02

11.47

8.62

12.61

6.35

11.94

7.71

9 1 O

11.54

16.41

13.03

11.43

11.57

11.72

11.48

8.48

11.21

11.20

7 08

12.73

19 ^7

1 A K.Q

4.92

10. 29

11.54

5.99

12.53

1 d 9^

n

nc

14.78

12.38

9 74

16.82

10.99

19.26

10.29

15.03

13.77

10.98

C

O+ash

2.68

2.71

2.72

- 2.72

2 74

2.75

2.75

2 77

2.79

2.79

2.81

2.84

2.84

2

QA

2.86

2.86

2

OQ

2.89

2.89

2.92

2.93

2.96

2.96

2 97

2 Q7

2.97

2.99

2 OQ

3.00

3.00

3.01

3.02

3.04

3.04

3.05

Calories.

6,823

6,598

6,596

6,575

6,724

6,700

6,717

6,855

6,806

6,757

6,714

6,881

6,883

6,727

6,697

6,811

6,805

6,866

6,879

6,829

6,756-

6,759

6,785

6,916

6,837

6,862

6,848

6,927

6,901

6,914

6 09ft

6,829

6,770

6,849

6,915

7,034

6,910

Moi

ture

1.4

2.2

6.0

4.3

5.9

5.2

4.0

1.3

8.4

4.' 3

5.2

8.9

2.9

6.3

3.1

2.6

2.7

6.5

5.8

3.9

5.7

2.4

2.5

9 9

3

0

5 1

3.2

4.3

1.2

3.8

.8

4 Q

1.4

2.9
128 

129 

130 

131

» 132 

- 133

£ 134 

134a 

_, 135 

? 135a 

- 136 

" 136a

.O

g 137 

138 

_. 139 

o 140 

141 

142

0 143

144 

145 

146 

146a 

146b 

146c 

147 

147a 

147b 

148 

149 

149a 

150 

151 

152 

153 

154 

154a

155 

156 

157 

158 

159 

160 

160a 

161 

161a 

162 

163

Wash. 2

Ky.7. ........

Ky.2.. .......

Ohio 11.......

Ind. ISA......

Ala.3.. .......

Colo. 3541..... 

K5-. 9B.......

111. 19B.......

Ind. 15........

Colo. 3640..... 

Ind. T. 3......

111.16.........

Va. 5A........

N. Mex. 5... . . 

Ind. 7.........

Wyo. 5........

111.11.........

Ind. T. 1......

Colo. 3946..... 

Colo. 3586..... 

Wyo. 4302.....

Colo. 3943..... 

Cal. 3773......

Ohio 7 ........

Ind. 7B.......

Colo. 3546.....

Tenn. 6. ......

Tenn. 9 A......

R.I.I........

Ind. 10........

Ohio 8........

Wyo. 3480.....

Tenn. 1 ....... 

Pa. 13. ........

Tenn. 8B......

Tenn. 7 A

Ala. 1 .........

Ind. T. 2......

Colo. 3936.....

Ga.l.. ........

Wyo. 4323..... 

Va.5B..; ....

Pa. 3. .........

Central City.........

Book Cliffs field.....

Book Cliffs field.....

Littles...............

Rifle Creek..........

Book Cliffs field.....

Book Cliffs field.....

Fork Ridge..........

Clifty. ...............

Wilder..............

Greys. ...............

Scranton........ ....

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. .

B. 

B. 

B. 

Sa. 

B. 

B. 

B. 

S. 

B. 

B.

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

B. 

G. 

B. 

B. 

B. ?

B. 

B.

B. 

B. 

B. 

B. 

B. 

Sb. 

B. 

Sa. 

A.

1.26 

1.32 

1.25 

1.19 

1.38 

1.24 

1.15 

1.58 

1.39 

i r **

L56 

1.20

1.50 

1.07 

1.56 

.69 

1.19 

1.25 

1.09 

1.52 

1.39

1.63 

1.63 

1.55 

1.48 

1.60 

1.19 

1.23 

1.24 

1.60 

1.01 

1.32 

.17 

1.26 

1.35 

1.79

1.65 

1.23

1.25 

1.29 

1.66 

1.72 

1.40 

1.13 

1.48 

.74 

.80

.38 

2.71 

3.72 

4.39 

1.69 

3.25 

.56 

.87 

3.10 

.64 

1.00 

.49

3.67 

8.33 

1.19 

.66 

.70 

3.88 

4.34 

.86 

2.07 

1 99

.71 

1.31 

.64 

.96 

1.14 

4.26 

3.21 

4.14 

.74 

.80 

.96 

.07 

4.17 

2.97 

.95

1.63 

2.19

4.84 

3.32 

.73 

1.56 

.44 

1.31 

.28 

.70 

.77

5.08 

5.06 

5.33 

4.71 

5.48 

5.41 

4.47 

5.14 

5.07 

4.51 

5.11 

5.38

4.85 

5.04 

4.94 

3.60 

4.79 

5.40 

4.91 

5.37 

4.84

5 1 4

5.32 

5.33 

4.65 

4.96 

5.36 

6.18 

5.14 

5.11 

5.38 

4.66 

4.64 

.69 

5.40 

5.21 

5.56

4.95 

5.02-

4.55 4.92' 

4.96 

5.00 

5.07 

4.09 

5.14 

3.85 

2.81

70.26 

67.80 

67.64 

67.72 

69.08 

68.01 

70.84 

69.83 

68.35 

70.55 

69.89 

70.32

68.18 

65.02 

70.14 

72.23 

70.95 

67.99 

68.22 

70.30 

69.91 

69.85

70.39 

70.00 

71.09 

70.70 

70.20 

67.50 

69.19 

68.94 

71.03 

72.14 

71.84 

76.63 

69.07 

70.18 

71.24

71.36 

71.25

69.59 

70.46 

72.16 

71.49 

72.65 

72.92 

72.97 

74. 33 ' 

75.21

10.60 

12.34 

12. 68 

8.84 

15.17 

12.80 

8.45 

16.47 

11.59 

13.11 

13.47 

16.87

10.52 

7.91 

12.17 

4.02 

7.59 

11.93 

8.30 

18.32 

10.64 

11.38 

16.47 

15.34 

15.74 

11.98 

15.63 

14.50 

10.40 

10.34 

15.16 

6.53 

6. 78 

2.99 

10.77 

11.52 

16.73

8.92 

6.96

5.36 

6.94 

7.85 

8.91 

13.49 

5.58 

18.45 

2.91 

4.08

12.42 

9.77 

9.38 

13.15 

7.20 

9.29 

14.53 

6.11 

10.50 

9.63 

8.97 

5.74

11.28 

12.63 

10.00 

18.80 

14.78 

9.55 

13.14 

3.63 

11.15 

10.35 

5.48 

6.39 

6.33 

9.92 

6.07 

6.37 

10.83 

10.23 

6.09 

14.86 

14.46 

19.45 

9.33 

8.76 

3.71

11.49 

13.35

14.41 

13.07 

12.64 

11.32 

6.95 

14.97 

1.68 

17.47 

16.33

3.05 

3.06 

3.06 

3.08 

3.08 

3.08 

3.08 

3.09 

3.09 

3.10 

3.11 

 3.11

3.12 

3.16 

3.16 

3.16 

3.17 

3.17 

3.18 

- 3.20 

3.21 

3.21 

3.21 

3.22 

3.22 

3.23 

3.23 

3.24 

3.26 

3.34 

3.34 

3.37 

3.38 

3.41 

3.43 

3.46 

3.48

3.48

3.52 

3.52 

3.52 

3.53 

3.55 

3.55 

3.62 

3.65 

3.68

7,084 

6,863 

6,966 

6,937 

6,898 

6,953 

7,007 

6,978 

6,985 

6,897 

6,979 

6,908

6,927 

6,854 

6,921 

6,929 

7,065 

6,920 

6,891 

6,955 

6,978 

7,011 

7,075 

7,024 

6,911 

6,877 

7,072 

7,086 

6,947 

7,020 

7.069 

7,159 

7,135 

6,229 

7,113 

7,055 

06,951

7,199 

7.221

7,096 

7,122 

7,199 

7.205 

7,243 

7,341 

7,358 

7.112 

6. 929

1.88 

5.64 

5.36 

1.87 

8.29 

5.39 

1.54 

5.63 

3.91 

3.87 

4.93 

5.21

3.45 

3.57 

4.61 

.73 

1.34 

5.50 

3.74 

6.00 

3.11 

3.87 

4.24 

4.84 

4.51 

5.42 

4.31 

4.86 

4.16 

2.76 

5.49 

1.02 

1.36 

.42 

2.85 

3.19 

5.45

1.87 

1.27

1.14 

1.36 

1.56 

1.70 

2.81 

.62 

4.20 

.45 

2.08

4

4

4

4

4

4

5

5

5

5

5

5

4

4

5

6

5

4

5

5

5

5

5

5

5

5

5

4

5

4

5

5

5

7

4

4

5

5

5

5

5

5

4

5

6

5

7

7

Coals more or less weathered.
TABLE 1. Ultimate analyses of 319 American coals, "air-dried" basis, from the chemical la

value and C: (0-\-ash) ratio of each coal Contin

No

164

1G5

Ififi

IGOa

107

168

ir>9

170

171

171a

I71h

171c

17?

173

173a

173b

174

174a

175

175a

176

176a

177

178

179

179a

180

181

18?

183

1S4

185

186

187

188

189

190

191

IP?

193

.Designation of

Tenn. 8A.....

111. 34A........

Ala.4.........

Colo. 3587.....

Ohiol2B......

Ohio 10.......

Pa. 6..........

111. 11C........

Ohio9A.......

Colo. 3D38.....

Colo. 3585.....

Colo. 3932.....

Ohio 12 A......

JCans 5

Wyo. 357a.....

Colo. 3939.....

Tenn. 4 ......

Colo. 4036.....

W. Va. 22B...

Colo. 4225.....

Pa. 17.........

Colo. 7573.....

W. Va. 25.....

Ark. 8.........

Colo. 4048.....

Ky.8.........

Ark. 12........

Ark.l.........

Utahl .......

Tenn. 5.......

Ohio 6........

Ind. T. 2C....:

Pa. 22.........

Md.l. ........

Pa. 12.........

W. Va. 22A

Pa.7... .......

Clifty. ....... .......

Belle Ellen..........

Mineral City. ........

EastMillsboro.......

Carterville. ..........

Clarion..............

Book Cliffs field.....

Oyster Ridge. .......

White...............

Spring Hill..........

(?)...................

Gatliff . ..............

Huff..... ............

Lieonier. ............

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B. 

B.

B.

Sa.

B.

B.

Sb.

Sb.

B.

B.

B.

B.

B.

B.

B.

Sb.

B.

B.

B.

N.

1.17

1.53

1.25

1.65

1.25

1.32

1.27

1.43

1.22

1.76

1.63

1.45

1.23

1.09

1.18

1.73

1.63

1.78

1.18

1.50

1.44

1.40

1:43

1 11

.53

1.86

1.23

1.38

1.47

1.45

1.43

1.69

1.78

1.17

1.88

1.58

1.^6

1.22

1.55

S.

2.51

 1.14

i ns

3 7ft

3.00

1.98

1.76

3.25

1 ^7

.42

4.07

3.86

.48

.52

1 ni

CO

1 ni

i ^fi

.66

.66

3 

CO

2.14

96

1 OO

1 *fift

1 O7

1.76

.57

3.38

3.47

1.25

1.03

1.51

2.21

.85

2.15

H.

4.97

4.96

4.89

5.07

5.55

4.67

4.99

4.67

5.05

5.52

5.21

5.03

4.96

5.10

5.17

5.13

5.49

5.06

5.69

4.83

5.32

5.02

5 Ofi

3 44

5 1fi

4.87

3.78

4.00

5.06

5.55

4.97

5.16

5.03

4.77

3.88

4.76

5.05

4.51

C.

70.45

71.55

73.09

72.46

71.28

72.87

72.80

72.07

73.45

72.62

73.98

71.44

71.90

74/41

73.87

73.62

73.65

70 70

74.41

74.61

72.68

7C 77

74.10

74 99

7C AQ

75.68

74.44

75.18

73.23

74.80

73.58

75.69

74.89

76.01

75.19

0.

10.55

5.96

10 1O

8

7C

10.84

10.23

14.22

1 0 CO

toco

8.60

7.40

13.62

8 

eg

16.61

8.47

19 IS

5.80

8 1 A

3 47

14.72

9

C1

4.15

9.81

12.21

6.53

9 81

7.76

8.87

6.44

3 PQ

7.36

8.89

3.72

A cVi

1 °. Ad

8 90

13.67

6.05

10.10

7.71

12.78

8.18

8.56

4.98

5.33

5.41

9.63

10.79

4.47

5.09

10.00

1 Q,1

10.09

5.87

12.31

5.82

7.39

9

OC

3 on

8.18

13.52

12.88

7.48

5.06

10.20

7.28

8.87

8.87

10.49

13.32

9.32

7.98

12.88

C

O+ash

0 CO

3.68

3.72

1 77

1 77

3.78

3.78

3.82

3.83

3.83

3.85

3.91

3.92

3.95

3.95

3.95

3.96

3 QQ

4.08

4.08

4.08

4.08

4.17

4.18

4.18

4.27

4.30

' 4.31

4.35

4.37

4.42

4.45

4.47

4.48

4.49

4.50

4.52

Calories.

7 1 70

7 324

7,287

o7, 207

7,280

7,368

7,301

7,263

7 111

7,429

7 189

7 ofiA

7,343

7,333

7 lift

7,441

7 091

7,465

7 344

o7, 316

7,461

7,608

7,365

7 244

7 564

7,598

7,450

7,501

7,595

7,456

7,489

7,425

7,505

7,632

7 4gg

7,621

7,6^.5

7.549

Moisture.

2 13

.98

4.17

1 69

1.27

2.36

2.47

2 71

4.78

1.58

1.84

2.90

1.77

4.18

3.51

1.09

3.33

1.95

2.16

.83

3 10

2

qo

1.22

1.17

1.99

2.34

1.35

2.25

1.47

1.43

.91

Q4

1.27

1.45

.92

F

5

5

5

4

C

5

5

5

C

A

5

5

5

5

5

7

c

6

5

4

5

5

5

5

f

C

5

6
194

1Q5

19f>

137

198

199

?00

?01

?n?

?,03

?,04

?0f>

?,07

?ns

?OSa

?,08b

?,oso

209

211

91 1o

212

01 o

?,14

215

91 ^Q

?1fi

?1fia

217 O-IQ

O1Q

99O

999

?24

?,?r.

r>i

?,?£

??9

?.?n

931

?,31a

231 b

Term. 9C......

Ark. 3-.-......

Pa. 21.........

Pa. 4... .. = ....

W. Va. 3. .....

W. Va. 23B . . .

W. Va. 5......

W. Va. 10. ....

Pa. 19.........

Mo. 4...........

Ky. IB........

W. Va. 2. .....

Ark. 7A. ......

Term. 2 . . ....

W. Va. 4B . . . .

Wyo. 4303.....

Colo. 4010.....

Ala. 3499......

W. Va. 23A...

Va.C... .......

Ala. 3745......

Colo. 3552 .....

Pa.9..........

W. Va. 11.....

Pa. 11.........

W. Va. 15.....

Wyo. 4299.....

W. Va.14.....

Ala. 3771.....".

Va. 4..........

Va. 2B........

W. Va. 1......

Pa. 10.........

Va.l.. ........

W. Va. 20. ...

W. Va.8......

Ky.O. ........

W. Va. 17.....

Pa. 5... .......

Pa. 16.........

Pa. 20.........

Ky.l. ........

Pa. 15B .......

W. Va. 18.....

Ala. 3744......

Colo. 4047.....

Straight Creek.......

Gatlifi. ..............

Bretz...... .........

Willow Creek........

Gulch...............

Coal Hill.... ........

Zenith...............

Miller Creek. ........

Straight Creek.......

Fallston.............

Coal basin ...........

B.

Sb.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

Sb.

B.

B.

B.

B.

B.

B.

B.

B.

Sa.

B.

Sb.

Sb.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

B.

Sp.

B.

B.

Sb.

B.

Sb.

B.

Sb.

B.

Sb.

B.

1.28

1.55

1.57

1.46

1.44

1.19

1.48

1.53

1 42

.75

1 71

1 17

1.81

1 si

1.56

1.45

1 °.P.

1.13

1 QQ

1.50

1 9Q

1.45

.85

1.50

1.53

1.55

1.27

1 07

1.38

1.48

1.41

1.55

1.33

1.16

1.85

1.18

1.45

1.33

1.83

.67

1 30

.90

1.29

1.07

1.30

99

1.26

1.08

1.16

3

CA

1.01

1.10

.94

.45

1.10

1.24

1 97

.88

2.01

2

AQ

.53

1.19

2.56

.71

.90

.'A

.81

94

.90

1.28

1.23

1.41

.92

.58

1 40

.89

1.65

1.10

2.96

1.24

4.06

.68

.67

.52

4.83

4.07

4.63

4 91

5.04

4 78'

4.80

4 Q9

5.77

5.06

K AQ

3 QQ

5.20

A £O

5.16

4 

OQ

5.13

3.74

5 9Q

4 00

4 

no

5 no

5 03

5

CQ

4.85

5.15

5 1 7

5.08

5.26

5

1 A

5.17

5

f\A

5.25

4

C1

4.46

5.01

5. £6

4.29

4.91

5.26

4.65

76.37

76.34

76.12

76.02

76.36

76.09

76.25

70 JC

75.89

76.37

TC QT

76.72

77.05

76.57

77.21

77 9Q

77 42

79 12

77 ^9

76.52

TO 1Q

78.21

78.67

78.51

78.16

78.47

7fi ^Q

70 7C

78.94

7O QC

78.78

79.00

79.16

78.23

78.31

77.52

79.65

79.50

79.77

7.27

4 Q1

7.47

5.78

6.C9

8.24

6.21

7.56

7.76

7.62

7.70

3 Q1

8.98-

5 AQ

12.64

9.46

7 9fi

7 go

3 

on

9 89

3 

CO

3.78

7.62

5 

CO

6.11

8.46

9 73

8

"3Q

7.61

7 =,£

9 01

5 

en

10.83

5

01

7.47

S

CO

8.80

2.<0

7.39

10.03

4.59

9.58

11.80

9.09

10.37

8.15

10.18

8.76

8

K.J

5

OO

8.54

7 on

12.29

7.03

10.38

3.23

6.32

8

AQ

7.71

10.30

6.30

12 21

C <>1

11.63

11.50

7 *?*?

8 63

3 48

8.43

5.75

4.42

5 

fin

6.37

6

0E

4.85

8

0ft.

2.82

8

00

6.11

RIO

4.65

W QO

4.44

5.92

3.21

8.64

4.54

4.57

' 4.61

4.62

4.62

4.G4

4.65

4.66

4. 67

4.68

4.69

4.70

4.71

4.74

4.77

4. 84

4.88

4.88

4.90

4.90

4.96

4.96

5.04

5.09

5.17

5.17

5.29

5.33

5.37

5.53

5.55

5.59

5.60

5.64

5.66

5.68

5.71

5.78

5.78

5.80

5.83

5.87

5.90

5.91

5.98

5.98

6.01

6.03

7,563

7,586

7,751

7,616

7,631

7,661

7,6S2

7,609

7,516

. 7, 623

7,700

7,413

7,630

7,626

7,812

7,860

7,613

7,643

7,757

7,764

t>7, 676

7,657

7,761

7 7d*?

7,713

7,855

7 791

7 -QO9

7,SC9

7,870

7,812

7,863

7,S07

7,864

7,812

7 964

7^692

7,955

7,781

7,963

8,115

7.977

1 43

.80

.97

97

1.00

1.46

.65

1.22

1.01

C OQ

1.57

1.46

.60

i iz*

1 99

1.21

1 19

1.58

.65

1.67

1 9Q

en

on

1.S6

1 T>

.98

2.40

1.48

1.35

1 00

1.70

.74

2.99

1.00.

1.47

.36

1.62

1.92

.48

1.28

1.52

.76

cn 

67

57

58

56

57

tc 

en 

70

54

fin 

C7 

59

55

64

59 

73

54

70

57

5^ 

=7 

co 

55 

57

57

r o 

58

56

62

^7 

68

CQ 

57

70

59

60

69

From shallow mine or country bank. b 
TABLE 1. Ultimate analyses of 319 American coals, "air-dried" basis, from the chemical la

value and C: (0-}-ash) ratio of each coal Con

No

909

900

904

9oe

236

9Q7

OQQ

9 on

9OQK

?40

241

?,W

?43'

?A4

9xc

?4f.

?47

248

?49

wo

Designation of

coal.

W. Va. 9......

Ky.5. ........

W. Va. 21.....

Ala. 6.........

Ark. 2.........

Pa. 15.. .......

Pa. 18.........

W. Va. 14.....

Ark. 3174......

Pa. "L"......

W. Va. 7......

Md. 2.........

Ind. T. 9......

Ala. 3770......

Va. 3... .......

Pa. 8... .......

W. Va. 13.....

W. Va. 12A...

W. Va. 12.....

W. Va. 6......

W. Va. 19.....

W. Va. 10.....

Lloydell.............

Paris................

Page.. ^... ..........

Big Sarfdy.. .........

Kind.

B.

B.

B.

B.

Sb.

Sb.

Sb.

B.

Sa.

Sb.

Sb.

Sb.

Sa.

B.

B.

Sb.

B.

Sb.

Sb.

Sb.

Sb.

Sb.

N.

1.63

1.61

1.52

1.45

1.40

1.17

1.23

1.56

1.49

1.27

1.05

1.49

1.68

1.55

1.63

1.29

1.34

1.33

1.70

1.60

1.07

S.

.80

.69

1.35

.63

1.90

3.88

1.55

1. O6

2.85

2.29

1.20

.86

1.24

.49

.68

.97

91

.69

.85

.66

.91

.57

H.

5.04

4.99

5.21

4.84

4.13

4.43

4.53

5.15

3.87

4.04

4.38

4.54

4.35

5.34

5.04

4.37

4.36

5.06

4.70

4.66

4. 53

C.

79.35

79.67

79.15

80.25

80.03

78.61

80.74

80.73

80.48

81.10

82.41

82.39

82.06

82.09

82.16

83.11

83.63

83.18

83.62

83.56

35.91

O.

6.39

9.23

7.83

5.94

3.20

1.82

3.02

8.12

2.04

2.99

5.87

9 49

2.26

6.69

5.91

3.43

5

Q1

3.03

3.36

4.23

4.13

3.24

Ash.

6.79

3.81

4.95

6.88

9.34

8.83

2.38

9.27

8.31

5.09

7 9Q

8.41

3.84

4.58

6.83

4.01

6.95

6.22

5.09

5.13

4.63

C

O+asb

6.03

6.10

6.19

6.26

6.38

6.60

6.81

7.01

7.11

7.18

7.52

7.68

7.69

7.79

7 8°.

8.10

8

09

8.38

8.68

8.97

9.01

10.91

Calories.

7,984

7,958

7,915

8,011

7,756

7,885

7,926

8,090

7,824

7,934

8,254

8,086

7,948

8,180

8,170

8

90,1

8,185

8,300

8,301

8,203

8,439

Moisture.

1.01

1.60

1.50

.85

.74

04

.38

2.05

.59

.64

.76

.74

.64

1.28

.87

.63

1.17

.62

1.93

.64

.68

.65
OXYGEN AND ASH AS IMPURITIES. 19 

ARRANGEMENT OF ANALYSES.

It must be borne in mind that the analyses in this table are arranged 

according to the numerical sequence of the C:(0 + ash) ratios of the 

samples. The calorific values determined directly from the same airdried samples by the Mahler bomb calorimeter are set down in the 

column adjoining that of the ratios. Most of the calorific determinations were made in duplicate.

It will be remembered that in the ultimate analyses of air-dried 

samples, such as are here considered, the highly variable remaining 

moisture is included in the percentages of hydrogen and oxygen. 

Therefore in many cases the greater part of the oxygen of the analysis belongs to the retained moisture. The amount of moisture, as set 

down to the right of the calories column in the table, varies from 

26.64 (No. 3, N. Dak., 3) to 0.34 (No. 237, Pa.,' 15). The fixed carbon and "volatile combustible matter" ascertained from the proximate analyses, also on the air-dried basis, are placed next beyond 

the moisture column. It will be seen that the percentages of ash range 

from 29.33 (No. 21, Mexico) to 2.38 (No. 239, W. Va., 14); and of oxygen from 38.57 (No. 2b, Wyo., 3694 a) to 1,82 (No. 237, Pa., 15). 

The arrangement of coals so widely varying in these two respects 

purely.on the basis of the numerical sequence of the C:(0 + ash) 

ratios results in a mingling of fuels of very different kinds, characters, 

and ages, even bringing low-grade subbituminous coals (black lignites) into incongruous juxtaposition with Paleozoic coals of advanced 

devolatilization, the high oxygen of the former being balanced by 

the high ash of the latter.

FUELS HIGH IN OXYGEN OR ASH.

To show by specific illustrations the relative importance of oxygen 

and ash as indicated by the calorimetric tests, a few of the more 

conspicuous examples maybe cited from Table 1: No. 8 (N. Dak., 1), 

from the Tertiary, has oxygen 27.15 and ash 12.24, the ratio of the 

carbon to them being 1.31; while No. 10 (Ind. T., 5), from the "Coal 

Measures," has oxygen 12.40 and ash 25.75, the ratio of carbon being 

1.37. In these two analyses the oxygen and ash are contrastingly 

paired. The difference between the calorific values of the two coals 

is not far from the value corresponding to the difference between the 

two ratios, as will be shown later. No. 25, a Fort Union coal, at 

Monarch, Wyo., shows oxygen 28.99 and ash 4.79; while in No. 27, 

from Ozone, Tenn., the percentages are nearly reversed, oxygen being 

4.90 and ash 28.53. The difference between the calorific values of

o The abnormally high oxygen of this Wyoming coal is the result of weathering. For an oxygen content 

nearer normal, sec No. 5 (N. Dak., 2B), with 35.80; or No. 25 (Wyo., 1), with 28.99. That several of the 

lignites show more oxygen than the peats is due to the lesser moisture in the peat samples.
20 THE EFFECT OF OXYGEN IN COAL.

these two coals accords within 1 per cent with the value corresponding to the difference in their C :(O + ash) ratios. Again, No. 30, a bony 

layer high in ash in the Pocahontas (lower Pottsville) bed, at Gary, 

W. Va., and No. 32, a Laramie coal, at Lafayette, Colo., are nearly 

paired, the oxygen being 3.97 and 24.95, respectively, and the ash 

28.77 and 6.32; neither of the calorific efficiencies differs 0.75 per 

cent from the calorific values corresponding to the carbon ratios. 

A still closer agreement with No. 32 is presented by No. 35, from 

Bonanza, Ark.; the fixed carbon in pure coal of the latter is 78.97, 

while that of No. 32 is 'but 53.69. The Paisley, 111. (No. 42), and 

the Sprague, Mo. (No. 43), coals have oxygen contents of 16.1 and 

8.46, respectively, their ash being 13.10 and 20.38; as compared with 

the calorific values corresponding to the respective ratios,0 2.06 and 

2.08, the former has ja deficiency of 36 calories, the latter an excess 

of 25. The agreement of No. 41 (Hanna, Wyo.) with the coals just 

cited is equally close in spite of its low ash, the ascertained calories being but 14 less than the number corresponding to its ratio, 

2.04. An almost equal agreement in calorific values is shown in the 

contrasting anaylsb., No. 64, from the Upper Cretaceous, at Gallup, 

N. Mex., and No. 65, from the "Coal Measures," at Yale, Kans., 6 

.in which the oxygen is 21.14 and 5.13 and the ash 7.10 and 21.82, 

respectively. The error is not much greater between No. 100, from 

the Upper Creta, ous, at Van Houten, N. Mex., and No. 101, from 

the Carboniferous, at Bugger, Ind., in both of which the oxygen, at 

9 and 15.76, is balanced by ash, 15.74 and 8.48.

FUELS OF LOWER ASH AND OXYGEN.

Passing on to coals of better quality, similar comparisons may be 

made between 119, 120, and 121, in which there is marked alternation in the amounts of these impurities, though the total difference

in the efficiency is less than 20 calories. A greater contrast in age 

and character of the samples is found in No. 140, from the basal 

Mississippian ("Lower Carboniferous"), at Blacksburg, Va., and No. 

144, from the Upper Cretaceous, at Rock Springs, Wyo. In the 

former the proportions are oxygen 4.02, ash 18.80; in the latter, 

oxygen 18.32 and ash 3.63. The Virginia coal is semianthracite, 

with a fixed carbon in pure coal of 86.89; the Wyoming is a subbituminous coal, having a fixed carbon of but 57.19. These have 

efficiencies, the first 33 and the other 30 calories less than the values 

corresponding to their respective ratios, 3.16 and 3.20. The efficiencies of No. 153, from the Indiana coal field, and No. 155, from the Tena For calorific values corresponding to the ratio means, and for percentage ratios of volatile carbon, fixed 

carbon, available hydrogen, etc., see the same numbers in Table 2 (pp. 26-33). 

t> Unusually high available hydrogen compensated by very high sulphur.
OXYGEN AND ASH AS IMPUEITIES. 21

nessee Pottsville, appear to conform very nearly to the means corresponding to the ratios, although the coals offer marked alternation in 

oxygen and ash. The Huntington, Ark., coal .(No. 182) has a iixed 

carbon (in pure coal) of 79.25, and a Mesaverde coal, at Price, Utah 

(No. 184), but 52.68. The oxygen and ash nearly reciprocate at 4.70 

and 12.88 against 12.21 and 5.06, the ratios being 4.30 and 4.35, respectively. The Huntington coal appears to have a deficiency of 60 

calories, while the Utah coal has an equal number in surplus, the 

variance in either case being not more than 0.8 per cent of the calorific 

value.

Not to weary the reader with the details of further illustrations, a 

few additional comparisons are suggested as follows: Nos. 185 and 

186; 193, 194, and 195; 199 and 200; 216 and 218; also Nos. 165 and 

167; 131 and 132; 94 and 95; 39 and 40.

The more conspicuous contrasts noted in so many of these analyses 

naturally involve great differences in the kind and stage of development or maturity of the compared coals, whose proximate association 

in the table is due to the sequence of the ratios. The regularity of 

the coals with similar analyses, though from^'different regions or of 

different kinds, is well illustrated by Nos. 6Q to 63; 91 and 92; 145 

and 146; 173 and 174; and 220 to 223.

RELATION TO CALORIFIC VAITyE.

However conspicuous or striking the contrasts offered by the examples specially cited above, the essential and most important evidence 

' for the approximately equivalent negative values of oxygen and ash 

lies in the relatively close conformity, throughout the whole series, 

of the ascertained calorific values to the C:(O + ash) ratios; so that 

not only do coals having the'same ratio closely approach the same 

efficiency values, but also the latter arrange themselves mainly in 

accordance with the sequence of the ratios. This may readily be 

noted in the series 25-50; 60-70; 87-125; 139-145; 164-176a; 182- 

201; 211a-226; and 241-250.

It must not be forgotten that in this treatment the hydrogen, 

sulphur, and nitrogen are assumed to be constant and therefore negligible; also that the oxygen of the analyses includes the oxygen of 

moisture as well as that really of the coal that is, presumably in 

hydrocarbon combination.

The nearness to equality in the negative values of oxygen and ash 

is indicated fairly distinctly in Table 1. In a later section it will 

become more distinct, in connection with the discussion of the limits 

of variation from the ratio means, and the effect of the neglected 

" constants" as a cause of variance from a strict sequence in the 

calorific values.
22 THE EFFECT OF OXYGEN IN COAL. 

CURVE PLATTED FROM C : (O+ASH) RATIOS AND EFFICIENCIES. 

DETERMINATION OF CURVE.

In order to ascertain the mean calorific values corresponding to 

the various ratios, the efficiencies of all the coals in the tables have 

been platted in Plate I. The horizontal component is the C: (0 + ash) 

ratio; the vertical is the heat value shown in the calorimeter tests. 

As thus platted the efficiencies are seen to describe a very clear and 

narrowly defined curve. The line in the figure is arbitrarily drawn 

to conform to the trend of this curve. Before proceeding, it may be 

remarked that the lower end of the curve is provisionally left dotted 

on account of the small number of wholly satisfactory analyses of 

the lowest grade coals, many samples having been more or less 

affected by exposure to the air. Also at the upper end additional 

analyses are needed for its more exact determination.

Considering that the hydrogen, sulphur, and nitrogen contents are 

here absolutely ignored and treated as negligible constants, the comparative proximity and regularity in the distribution of the efficiencies 

along the course of the curve is certainly remarkable. This regularity is explained (see p. 44) as due to the dominant control of the 

carbon, on the one hand, balanced by the chief impurities, oxygen 

and ash, on the other, in determining the calorific efficiencies of the 

ordinary types of the fuels, the hydrogen being either relatively stationary or, when in excess, more or'less completely counteracted 

by relatively high sulphur, nitrogen, or unusually high ash, which 

may be slightly more deleterious than the oxygen. By referring to 

Table 1 it will be observed that the instances of wider departure 

from the curve are largely confined either to the weathered samples or 

to approaching anthracitization. The 'curve is particularly interesting 

because it is adjusted to a miscellaneous collection of coals of all

grades, ages, and localities. It is not improbable that slight readjustments or special curves will be required for special groups of coals, like 

the cannels, or to suit the peculiarities of the coals of a given area.

DETAILED STUDY OF A CURVE SEGMENT.

The relative values of oxygen and ash and the approximation of the 

curve are diagrammatically expressed in Plate II, which shows on a 

large scale a section of the curve, embracing Nos. 25-50 of Table 1. 

Several of the intercalated analyses of samples, in some instances 

weathered, collected by the field geologists and recently published 

in U. S. Geol. Survey Bulletin 316, are here omitted. All fuels 

tested by the Survey are, however, included. The samples represent 

coals in Wyoming, Montana, Illinois, Tennessee, Missouri, West 

Virginia, Colorado, New Mexico, Arkansas, Iowa, and Washington. 

For description of the kind and age of each coal the reader is referred
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE I

Calories

C p.c. 

0+Ash

.50 LOO 1.50 £.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 

RATIO-EFFICIENCY CURVE OF COALS TABULATED.

6.50 7.00 7.50 8.00 8.50 9.00 9.50 10.00 10.50 11.00
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE

Variance from corve.-Cals. 35 29 24 -"37 5 32 35 25 10 ,14 35 25 12 76 ?

8 5 S S 3

Nitrogen, sulphur, 

end hydrogen (J

'" Total 

g < carbon

29 30 31 32 33a 35 36 37 38 39 40 42 .43 44 45 .46 48 

33 34 41 .46u 49 NUMBER IN TABLES 

AVAILABLE" HYDROGEN

MOISTURE IN 

AIR-DRIED COAL

SEGMENT OF RATIO-EFFICIENCY CURVE.
OXYGEN AND ASH AS IMPURITIES. 23

to Table 1. The segment of the curve taken from Plate I occupies 

the upper part of the diagram. As in Plate I, the vertical component 

represents the calorific efficiency and the horizontal component represents the C:(0 + ash) ratio of the coal.

The lower middle portion of the diagram shows the ash, oxygen, and 

carbon of the respective analyses, each analysis being platted in a 

position corresponding to that of its ratio in the horizontal component 

of the curve. The hydrogen, sulphur, and nitrogen, whose aggregate 

complete the 100 per cent in the analysis, are left blank and undifferentiated above the carbon. For information, what is termed "available" hydrogen ( H -^ J and the moisture contained in the air-dried

coal are separately platted at the base of the diagram.

The* disposition of the calorific values close along the line of the 

curve in Plate II seems to indicate (1) the approximately equal 

importance of oxygen and ash in impairing the efficiency of the 

coal in the calorimeter; (2) the relatively close agreement of the 

ascertained efficiencies to the C:(0 + ash) ratio-efficiency curve; (3) 

the dominant control of the carbon, oxygen, and ash in determining 

the calorific value of the coal; and consequently (4) the relative constancy or negligibility of the other elements (assumed constants) 

nitrogen, sulphur, and hydrogen.

VARIATIONS FROM THE CURVE.

The curve errors that is, the variations of the actually ascertained 

calorific values from the curve line are noted, each in horizontal 

position corresponding to the analysis, at the upper border of the 

diagram. A review of these errors or variations shows an average 

departure of but 29 calories for the 29 analyses of the diagram.

In this connection it may be interesting to compare the calorimetrically determined values with those indicated by the curve and 

with the efficiencies as calculated .from the chemical analyses. Reference to Professional Paper No. 48 of the Survey, in which such 

calculations of the efficiencies of coals were published, shows that 

eight of the samples which reappear in this diagram are included in 

that report. a The greatest variance in the chemical calculations of 

these eight analyses is 171 calories. The average variance is 89 calories. The average ratio-efficiency curve error for the same eight analyses, as shown in the diagram, is 23 calories; the highest individual 

error in the entire diagram is 76 calories.

The efficiency variance, that is, the variation of the calorimeter determination from the ratio C : (0 + ash) efficiency curve as read with

a Report on the operations of the coal-testing plant of the U. S. Geological Survey at the Louisiana Purchase Exposition, St. Louis, Mo., 1904: Prof. Paper U. S. Geol. Survey No. 48, 1900. The samples 

there included are as follows: No. 25, error + 171; No. 31, error + 119; No. 32, error + 130; No. 35, 

error + 00; No. 39, error -f 44; No. 43, error - 15; No. 44, error + 140; No. 48, error + 29.
24 THE EFFECT OF. OXYGEN IN COAL.

some care from the large-scale original of Plate I is noted for each 

of the 319 analyses in a column at the right in Table 2. The curve 

drawn in the diagram (PL I) is not entirely regular nor mathematically correct, but it is probable that its subsequent correction, based on 

additional data, will have the effect of lowering the mean variances 

of the analyses as now platted. The calorific variances in Table 2 

are therefore subject to revision. Omitting from further consideration the Rhode Island graphitized coal, which, being incombustible 

in its natural state, can not be regarded from the fuel standpoint as a 

coal, the highest error for an individual analysis is 312 calories, for 

the anthracite culm (No. 163) at Scranton. For the 318 analyses 

the average error is 67.2 calories. This includes the weathered coals 

and samples from shallow country banks and prospects, as well as 

the coals undergoing the final devolatilization marking anth'racitization, all of which, as has already been observed, show relatively 

large errors. If, however, we but exclude 18 of the highest coals, 

embracing those having a fixed carbon of over 79 per cent in pure

VC coal and a -p- ratio of less than 9.25 (per cent) we shall have for the

300 remaining analyses a mean error of 60.09 calories. This average, 

it may be noted, does not exclude the weathered coals in the table.

COMPARISON WITH CALCULATED THERMAL UNITS.

Referring again to Professional .Paper 48, in which the calorific 

values as calculated from the chemical analyses are published, we 

find that among the 57 ultimate coal analyses there given, all of which 

are included in Tables 1 and 2, the greatest individual error 0 is 312, 

as large as the maximum in all the coals of the tables,while the average 

error is 87.5 calories. The average ratio-efficiency curve error for 

the same 57 analyses, as shown in Table 2, is 58.7 calories. It may 

be proper to allow 2 or 3 calories additional to the average of Table 2 

for personal equation in reading from the curve. In passing we may 

note that in very many cases the curve error appears to be less than 

the probable error of the calorimeter., The empirical anticalorific 

values of ash and oxygen as roughly calculated from the curve and 

the influence of sulphur in the coals are considered later (pp. 39,44).

FORECAST OF FUEL EFFICIENCY FROM RATIOS. ' i

The close relationship between the calorific values and the curve 

not only conclusively shows the nearly equal anticalorific values of 

the oxygen and ash, it also shows that the heat value of the coal as a 

whole is practically determined by the balance between these two 

principal impurities, on the one hand, and the total carbon on the 

other. The ordinary method of estimating the heat value of a coal,

a For West Virginia C (No. 248) a coking coal from Rush Run.
OXYGEN AND ASH AS IMPURITIES. ' 25

in accordance with Du Long's formula, generally used by chemists, is 

to calculate the sum of the heat units afforded by the carbon, hydrogen, and sulphur. The formula as recommended by the committee

of the American Chemical Society is 80SOC + 34460 (H- §) + 2250S. a

o

The comparative study here presented demonstrates an approximate 

negative parity of oxygen and ash assumed in the application of 

Du Long's formula. It is surprising that a simple process like the 

ratio-efficency curve which takes account only of the carbon, the 

preponderant source of heat units, and of the two great anticalorific ingredients of the fuel, should in a relative way so nearly 

indicate its calorific value. Such an effect seems explicable only (1) 

by the relatively uniform amount of heat contributed by the hydrogen as compared to that of the variable carbon, notwithstanding its 

great heating power; and (2) by the relatively constant negative 

potency, as well as proximity to anticalorific equality of ash and

oxygen, whether the latter be in hydrocarbon combination or in the 

form of moisture. In this connection it may be noted that the 

calorific value in No. 2b is but 150 calories below the curve, though 

the coal contains no available hydrogen whatever, according to the 

analysis.

That the curve errors are not more exaggerated on account of the 

variability of the hydrogen, both in total amount and in the "available" form, is surprising. In the high-grade cannels, like that at 

Lesley, Ky. (H 6.82, C 73.54, 0 7.95, ash 9.35, moisture 1.31), and 

in the bogheads, the relatively high hydrogen produces an efficiency 

considerably above the curve. For this class of coals either a coefficient for excess may be used or a higher curve drawn.

RELATIONS IN MOISTURE-FREE COALS. 

RECALCULATION OF ANALYSES.

In Table 1 the analyses of the air-dried coals naturally included 

under the hydrogen and oxygen percentages the moisture remaining 

in the fuel. For the purpose of observing the true proportions of 

the oxygen and hydrogen assumed to belong to the moisture-free 

coals themselves it is necessary to' take from the percentages this 

included moisture. In Table 2 the moisture is excluded from the 

oxygen and hydrogen columns. Yet in order t6 preserve the conformity of the analysis to the original air-dried status of the fuel, on 

the basis of which the calorific values were actually determined, the 

moisture is set down as a separate entry, included in the 100 per cent 

of the analysis. Ash, carbon, nitrogen, and sulphur remain as 

before. The fixed carbon and the volatile matter, as determined by 

the proximate analysis, are repeated from Table 1, as also are the 

C: (O + ash) ratios and the calorific values.

« Jour. Am. Chem. Soc., vol. 21, p. 1130.
TABLE 2. The coals of Table 1, showing moisture-free hydrogen and oxygen; fixed carbon in pur

ratios; "available" hydrogen; and variance from C: (0-}-ash) r

No.

1 

2 

2a 

2b 

3 

4 

4a 

5 

6 

7 

8 

9 

9a 

10 

11 

12 

12a 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

25a 

26 

27 

28 

28a 

29 

30 

31

Designation of coal.

N. Dak. IB..............

Mont. 3701... ............

Wyo. 3694...............

N. Dak. 3.... ............

Ark. 10..................

N. Dak.2B..............

Fla. 1....................

Tex. 1...................

N. Dak. 1.... ............

Wyo. 3..................

Wyo. 3892. ..............

Ind.T. 5.. ..............

Cal.l. ...................

Mo. 7C..... ..............

Wyo. 2326...............

N.Dak.2.. ..............

111.2.....................

Mo. 7A..................

Mo. 3....................

N. Mex. 2.. ..............

Wyo.2. ........ .........

Wyo. 213 ................

Tex. 4...................

Mo. 10...................

Tex. 3...................

Wyo. 1..................

I11.7A...................

Tenn. 11.................

Mo. 7B..................

Colo. 3856................

Mont. 2..................

W. Va. 24...............

Mont. 1..................

N.

1.40 

.55 

.65 

.85 

1.39 

.91 

.65 

.88 

2.56 

.95 

.71 

.72 

1.40 

1.22 

.73 

.98 

.88 

.91 

.78 

1.01 

.92 

.98 

.80 

1.06 

.85 

.96 

.97 

.97 

1.18 

1.09 

.65 

.99 

1.13 

1.02 

1.35 

1.14 

.66 

1.36

S.

0.58 

3.95. 

.66 

.61 

1.32 

.65 

1.55 

.71 

.49 

1.04 

2.02 

6.86 

2.85 

4.06 

3.40 

3.47 

4.78 

.63 

4.30 

3.46 

4.13 

1.30 

4.17 

.71 

4.22 

1.02 

.70 

4.28 

1.30 

.63 

1.71 

4.63 

.92 

4.13 

.60 

.62 

.55 

1.76

H(-HaO).

4.05 

2.82 

2.83 

2.91 

2.92 

3.47 

2.95 

3.13 

4.59 

4.08 

3.51 

3.63 

3.44 

3.54 

4.32 

3.67 

4.00 

3.75 

3.98 

3.83 

3.91 

4.15 

4.24 

4.10 

4.07 

3.87 

3.98 

3.85 

4.04 

4.13 

3.66 

3.98 

3.82 

3.99 

4.40 

4.16 

3.27 

4.24

C.

40.78 

44.11 

48.01 

48.65 

47.45 

48.51 

48.55 

50.79 

51.18 

52.06 

52.66 

49.59 

52.58 

52.39 

52.83 

53.55 

52.53 

55.16 

54.06 

54.30 

54.79 

56.71 

55.29 

57.31 

55.84 

58.97 

58.83 

57.25 

58.43 

58.41 

59.65 

57.43 

60.56 

57.82 

60.49 

CO. 97 

62.36 

60.41

O (-H2O).

18.87 

11.01 

14.73 

26.28 

11.40 

14.36 

12.78 

15. 62 

22.31 

13.62 

13.45 

9.42 

13.67 

7.30 

12.37 

8.28 

12.72 

16.11 

7.61 

7.65 

7.45 

9.51 

10.51 

16.36 

8.60 

5.55 

15.80 

8.12 

14.88 

13.26 

11.13 

7.96 

3.78 

7.05 

9.55 

11.81 

3.51 

11.96

Ash.

20.74 

12.75 

18.00 

6.87 

8.88 

12.97 

9.41 

6.10 

5.68 

14.85 

12.24 

17.20 

14.75 

25.75 

17.29- 

27.57 

17.35 

6.71 

24.16 

22.35 

23.30 

19.22 

22.26 

9.81 

21.77 

29.33 

9.96 

23.76 

10.30 

4.79 

18.63 

18.22 

28.53 

22.82 

19.47 

' 15.92 

28.77 

11.22

H2O.*

13.60 

24.82 

15.12 

13.83 

26.64 

19.13 

24. 11 

22.77 

13.19 

13.40 

15.42 

12.58 

11.31 

5.74 

9.05 

2.48 

7.74 

16.73 

5.31 

7.41 

5.51 

8.13 

2.73 

10.66 

4.64 

.91 

9.76 

1.77 

9.88 

17.62 

4.57 

6.80 

1.26 

2.17 

4.14 

5.39 

.52 

9.05

C

O+ash

0.79 

.96 

1.04 

1.07 

1.08 

1.09 

1.11 

1.21 

1.28 

1.29 

1.31 

1.31 

1.36 

1.37 

1.41 

1.41 

1.42 

1.46 

1.48 

1.48 

1.56 

1.57 

1.57 

1.60 

1.62 

1.63 

1.71 

1.71 

1.72 

1.73 

1.76 

1.78 

1.81 

1.81 

1.85 

1.87 

1.90 

1.93

C

r

4

o4

6 4

^4

o4

4

64

4

4

5

5

5

c5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

5

6

6

6

5
OXYGEN AND ASH AS" IMPURITIES. 27

'O 

T CO CO CO I-H O5 OS CO 

-. 

r-l CO IN <N T)< p i-l .-I <N o TP Cl T>> IN CO U

1 +.i +++++ 1 1 1 1 1 1 ++77 1 i ++ i +++7 i +

N<NIN<NIN <N IN <N CM IN <N IN CO CO CO IN IN i-H <N <N CN N CO CO <N CO CO CO CO CO CN CN IN IN CO CN COO) CCMC^CN COI

S

^ O)

oo S

CO Q;

i ICOPCOO5CM

- 

.3 fe h> 03

^^

co <;'~!§fq N' " i M ^ xS55

fl"' 0« g l>'§^5 ^S 2 0

"8§ ': § ':

<<N;$CQCO -.

H IN CO M -* 'O O 

3 CO CO CO CO CO cocococococo'5 CO < 'r-^"V1 -^-4'*'1'"^' 5«OOol^ODO>O-H5lNf5ScNCOcC-i"O>5?«5t^|2oOOlPpHIN 

3,'*-T-^-T'7'TriO>OU5 1O«5S 1« 1'5'O'">nu5"O«3io"5'O«5COtO
TABLE 2. The coals of Table 1, showing moisture-free hydrogen and oxygen; fixed carbon in pure 

ratios; "available" hydrogen; and variance from C :(0+ash) ratio and 

No.

62a 

63 

64 

65 

66 

66a 

67 

68 

69 

70 

71 

72 

72a 

73 

73a 

73 b 

73c 

74 

75 

75a 

75b 

76 

77 

78 

79 

80 

81 

81a 

82 

83 

84 

84a 

85 

86 

87 

88 

89 

90

Designation of coal.

Utah 4013.. ..............

N. Mex. 1.. ..............

Kans. 2B .................

Incl. 14....'. ..............

Ind. 13...................

Ind. 4....................

111.30.....................

111.21........ ............

111. 22B...................

Ind. T. 4.................

Colo. 3545.................

111.31.....................

Colo. 3490.................

Mont. 4115.. ... .....

Wyo. 2283................

Ind. 2....................

Ind. 7....................

Colo. 3462.............. ..

Colo. 3704.................

111. 14.....................

Ohio 3. .......... .....

111. 12.....................

Ind. 6....................

111. 9A....................

Ariz. 4112.................

111.26.....................

Wyo. 6...................

111. 19E.......... ."........

Colo. 3703.................

Ala. 2B... ................

N. Mex. 3A. ..............

Ind. 16................ ..

Kans. 6...................

Tenn. 9B.................

Mo. 5.....................

N.

1.30 

.93 

1.05 

1.11 

.97 

1.20 

.87 

1.24 

1.03 

1.22 

1.00 

1.38 

1.47 

1.14 

1.13 

.92 

1.03 

1.25 

.94 

1.22 

1.40 

1.19 

1.28 

1.14 

.94 1.19' 

1.04 

1.28 

1.21 

1.10 

1.53 

1.12 

1.52 

1.25 

1.13 

1.14 

1.26 

1.02

S.

.47 

' 6.83 

.64 

5.03 

5.34 

.76 

3.37 

2.59 

4.80 

V54 

4.90 

4.02 

.66 

4.05 

.89 

2.43 

.58 

4.60 

3.85 

1.14 

.54 

4.52 

1.88 

3.61 

6.40 

4.63 

4.43 

.42 

4.02 

.55 

.54 

.60 

1.14 

.74 

4.50 

4.00 

.78 

5.68

H(-HjO).

4.14 

4.43 

4.52 

4.09 

4.51 

4.40 

4.40 

4.26 

4.56 

4.30 

4.29 

4.29 

4.47 

4.41 

4.44 

3.92 

4.25 

4.42 

4.21 

4.57 

4.25 

. 4.43 

4.36 

4.33 

4.31 

4.49 

4.63 

4.65 

4.37 

4.85 

3.95 

4.24 

4.21 

4.67 

4.50 

4.31 

4.56 

4.50

C.

64.88 

60.62 

64.34 

62.65 

62.05 

64.95 

63.39 

64.10 

62.60 

64.76 

62.99 

63.21 

65.05 

63.47 

65.51 

65.17 

65. 76 

62.97 

63.70 

65.33 

66.12 

63.85 

65.62 

64.85 

63.14 

64.22 

64.49 

66.81 

65.02 

66.95 

67.48 

67.42 

67.35 

67.54 

04.82 

65.65 

67.76 

64.52

0 (-H2 0).

15.56 

7.14 

11.49 

3.79 

8.04 

14.03 

7.54 

8.18 

9.29 

10.24 

8.40 

8.79 

12.07 

8.49 

11.44 

9.37 

16.07 

7.01 

8.33 

12.71 

14.00 

8.08 

8.57 

7.87 

4.71 

0.25 

8.62 

12.90 

8.12 

14.29 

- 10. 31 

14.93 

8.65 

7.31 

7.88 

5.89 

5.09 

7.20

Ash.

8.53 

15.53 

7.10 

21.82 

14.75 

7.42 

12.81 

16.05 

14.45 

12.20 

16.36 

13.40 

0.2S 

14.67 

10.42 

14.49 

3.43 

13.51 

11.61 

6.37 

4.78 

12.80 

12.05 

13.43 

18.27 

13.31 

11.80 

4.05 

13.85 

3.52 

10.92 

3.02 

14.84 

17.01 

12.49 

16.92 

19.47 

15.37

H2O.*

'5.12 

4.52 

10.86 

1.51 

4.34 

7.18 

7.62 

3.58 

3.27 

5.74 

2.06 

4.91 

10.00 

3.77 

6.17 

3.70 

8.88 

6.24 

7.36 

8.66 

8.91 

5.13 

6.24 

4.77 

2.23 

5.91 

4.99 

9.80 

3.41 

8.68 

5.27 

8.67 

2.29 

1.48 

4.68 

2.09 

1.03 

1.71

C

O+ash

2. 26 

2.27 

2.28 

2.32 

2.33 

2.33 

2.34 

2.34 

2.35 

2.35 

2.36 

2.38 

2.38 

2.39 

2.39 

2.40 

2.40 

2.41 

2.41 

2.44 

2.48 

2.50 

2.51 

2.54 

2.54 

2.58 

2.59 

2.59 

2.60 

2.61 

2.61 

2.62 

2.63 

2.63 

2.64 

2.66 

2.66 

2.69

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TABLE 2 . The coals of Table 1 , showing moisture-free hydrogen and oxygen; fixed carbon in pur

ratios; "available" hydrogen; and variance from C : (0 -\-ash) ratio an

No.

135 

135a 

136 

136a 

137 

138 

139 

140 

141 

142 

143 

144 

145 

146 

146a 

146b 

l'46c 

147 

147a 

147b 

148 

149 

149a 

150 

151 

152 

153 

154 

154a 

155 

156 

157 

158 

159 

160 

160a 

161 

161a

Designation of coal.

Ky. 9B..................

111. 19D..................

Ind. 15..................

Colo. 3640................

Ind. T. 3................

Kans. 4..................

111.16....................

Va. 5A. ........ .........

N. Mex.5...... .........

Ind.7. ..................

Wyo.5. .................

111.11...................

Ind. T. 1................

Colo. 3946.... ...........

Colo. 3586...............

Wyo. 4302. ..............

111. 19B. .................

Colo. 3943...............

Cal. 3773.. ...............

Ohio7....... ...........

Ind. 7B. ................

Colo. 3546....... .........

Tenn.6. ................

Tenn. 9A................

R.I.I...................

Ind. 10..................

OhioS. .................

Wyo. 3480...............

Pa. 13. ..................

Tenn. 1. ................

Tenn. 8B................

Tenn. 7A................

Ala.l.. .................

Ind. T. 2............. ..

Colo. 3936...............

Ga. 1 ....................

Wyo. 4323...............

N.

1.39 

1.56

1.56 

1.20 

1.50 

1.07 

1.56 

.69 

1.19 

1.25 

1.09 

1.52 

1.39 

1.29 

1.63 

1.63 

1.55 

1.48 

1.60 

1.19 

1.23 

1.24 

1.60 

1.01 

1.32 

.17 

1.26 

1.35 

1.79 

1.23 

1.65 

1.25 

1.29 

1.66 

1.72 

1.40 

1.13 

1.48

S.

3.10 

.64 

1.00 

.49 

3.67 

8.33 

1.19 

.66 

.70 

3.88 

4.34 

.86 

2.07 

1.99 

.71 

1.31 

.64 

.96 

1.14 

4.26 

3.21 

4.14 

.74 

.80 

.96 

.07 

4.17 

2.97 

.95 

2.19 

1.63 

4.84 

3.32 

.73 

1.56 

.44 

1.31 

.28

H(-H2 0).

4.64 

4.08 

4.56 

4.80 

4.47 

4.64 

4.43 

3.52 

4.64 

4.79 

4.49 

4.70 

4.49 

4.71 

4.85 

4.79 

4.14 

4.36 

4.88 

5.64 

4.68 

4.80 

4.77 

4.55 

4.49 

.64 

5.08 

4.86 

4.95 

4.88 

4.74 

4.42 

4.77 

4.79 

4.81 

4.76 

4.02 

4.66

C.

68.35 

70.55 

69.89 

70.32 

68.18 

65.02 

70.14 

72.23 

70.95 

67.99 

68.22 

70.30 

69.91 

 69. 85 

70.39 

70.00 

71.09 

70.70 

70.20 

67.50 

. 69.19 

68. 9.4 

71.03 

72.14 

71.84 

76.63 

69.07 

70.18 

71.24 

71.25 

71.36 

69.59 

70.46 

72.16 

71.49 

72.65 

72.92 

72.97

O (-H2O).

8.11 

9.67 

8.09 

12.24 

7.45 

4.74 

8.07 

3.37 

6.40 

7.04 

4.98 

12.99 

7.88 

7.94 

12.70 

11.04 

11.63 

7.16 

11.80 

10.18 

6.70 

7.89 

10.28 

5.62 

5.57 

2.62 

8.24 

8.68 

11.89 

5.83 

7.26 

4.35 

5.73 

6.46 

7.40 

10.99 

5.03 

14.57

Ash.

10.50 

9.63 

8.97 

5.74 

11.28 

12.63 

10.00 

18.80 

14.78 

9.55 

13.14 

3.63 

11.15 

10.35 

5.48 

6.39 

6.33 

9.92 

6.07 

6.37 

10.83 

10.23 

6.09 

14.86 

14.46 

19.45 

9.33 

8.76 

3.71 

13.35 

11.49 

14.41 

13.07 

12.64 

11.32 

6.95 

14.97 

1.68

H2O.*

3.91 

3.87 

4.93 

5.21 

3.46 

3.57 

4.61 

.73 

1.34 

5.50 

3.74 

6.00 

3.11 

3.87 

4.24 

4.84 

4.62 

5.42 

4.31 

4.86 

4.16 

2.76 

5.49 

1.02 

1.36 

.42 

2.85 

3.19 

5.45 

1.27 

1.87 

1.14 

1.36 

1.56 

1.70 

2.81 

.62 

4.36

C

O+ash

3.09 

3.10 

3.11 

3.11 

3.12 

3.16 

3.16 

3.16 

3.17 

3.17 

3.18 

3.20 

3.21 

3.21 

3.21 

3.22 

3.22 

3.23 

3.23 

3.24 

3.26 

3.34 

3.34 

3.37 

3.38 

3.41 

3.43 

3.46 

3.48 

3.50 

3.48 

3.52 

3.52 

3.52 

3.53 

3.55 

3.55 

3.62

C

ri

6

6

6

6

6

6

6

6

7

6

6

6

6

7

7

7

6

6

7

7

' 6

7

7

7

7

6

7

7

o6

7

7

7

7

7

7

7

7

7
162 

163 

164 

165 

22 166 

M 166a 

£ 167 

f 168 

1 169 

w 170 

£ 171 

." 171a 

w 171b 

go 171c 

f 172 

1 173 

§ 173a 

1 173b 

174 

1 174a 

05 175 

175a 

176 

176a 

177 

178 

179 

179a 

180 

181

189

183 

184 

185 

186 

187 

188 

189 

190 

191 

192 

193 

194 

195 

198 

197 

198 

199 

200

Va. 5B ..................

Term. 8A.. ..............

I11.34A..................

Ala. 4...................

Ohio 12B ................

Ohio 10.................

Pa. 6....................

m. iic. ..................

OhioQA. ...............

Colo. 3938...............

Colo. 3585......I........

Colo. 3932......... .......

Wyo. 3570...............

W. Va. 22B....... .......

Colo. 4225................

Pa. 17...................

Colo. 7573................

W. Va. 25...............

Ohio 4. ..................

Ark 8............ ........

Colo. 4048... .............

Ky.8......... ...........

Ark. 12... ...............

ArV 1

Ohio 5.'... ........ .'.'.'..'..

Utah 1. ..................

Ind. T. 2C... ............

Pa. 22...................

Md.l...... ..............

Pa. 12...................

W. Va. 22A. .............

Pa 7

Ark. 3...................

W.Va.3. ........ .......

W.Va.23B....... .......

W. Va. 5................

* Moisture 

<* Coals me 

b From sh

.74 

.80 

1.17 

1.53 

1.25 

1.65 

1.25 

1.32 

1.27 

1.43 

1.22 

1.76 

1.63 

1.45 

1.23 

1.09 

1.18 

1.73 

1.63 

1.78 

1.18 

1.50 

1.44 

1.40 

1.43 

1.33 

.53 

1.86 

1.23 

1.38 

1.47 

1.45 

1.43 

1.69 

1.78 

1.17 

1.88 

1.58 

1.32 

1.4fi 

1.22 

1.55 

1.28 

1.55 

1.57 

1.46 

1.44 

1.19 

1.48

(H20) i 

re or les 

allow mi

.70 

.77 

4.45 

2.51 

1.14 

1.08 

3.70 

3.00 

1.98 

1.76 

3.25 

.54 

1.37 

.42 

4.07 

3.86 

.48 

.52 

1.03 

-.53 

1.04 

1.03 

1.56 

.66 

.66 

3.52 

2.14 

.96 

1.22 

1.68

1 9.7

1.76 

.57 

3.38 

1.02 

3.47 

1.85 

1.03 

1.51 

2.21 

.85 

2.15 

.67 

1.30 

.90 

1.29 

1.07 

1.36 

1.99

s includ 

5 weathe 

ne or co

3.80 

2.58 

4.85 

4.72 

4.78 

5.18 

4.88 

5.30 

4.53 

4.73 

4.40 

4.75 

4.99 

4.86 

4.85 

4.76 

4.56 

4. 85 

4.93 

5.03 

4.87 

5.30 

4.71 

4.95 

4.80 

4.82 

3.35 

5.02 

4.61 

3.64

3 «7

4.84 

5.29 

4. 82 

5.06 

5.00 

4.87 

4.67 

3.78 

4.62 

4.89 

4.41 

4.67 

3.98 

4.52. 

4.71 

4.80 

4.88 

4.71

3d as a separ 

red. 

intry bank.

74.33 

75.21 

70.45 

71.55 

73.09 

72.46 

71.13 

71.28 

72.87 

72.80 

72.07 

73.45 

72.62 

73.96 

71.44 

71.90 

74.41 

73.87 

73.62 

73.65 

74.16 

73.73 

74.06 

74.41 

74.61 

72.68 

75.77 

74.10 

74.99 

75.49

7R fiS

74.44 

75.18 

73.23 

74.80 

73.58 

7,4. 50 

75. e9 

76.28 

74.89 

76.01 

75.19 

76.37 

76.37 

76.34 

76.00 

76.12 

76.02 

76.32

ate perct

2.51 

2.23 

4.57 

8.66 

5.09 

9.41 

7.25 

9.15 

5.30 

8.74 

8.04 

11.79 

9.28 

10.69 

7.20 

5.76 

10.80 

11.04 

7.01 

12.89 

6.92 

9.06 

4.83 

9.43 

9.16 

6.24 

2.73 

11.96 

7.44 

3.07

3 fifi

8.04 

10.13 

5.30 

7.81 

6.45 

6.60 

5.63 

2.85 

6.23 

7.60 

x 2.90 

6.00 

4.20 

6.61 

4.92 

5.20 

6.94 

5.63

jntage to coi

17.47 

16.33 

13.64 

8.90 

13.67 

6.05 

10.10 

7.71 

12.78 

8.18 

8.56 

4.98 

5.33 

5.41 

9.63 

10.79 

4.47 

5.09 

10.00 

1.94 

10.09 

5.87 

12.31 

5.82 

7.39 

9.25 

14.65 

3.00 

8.18 

13.52 

19. RS 

7.48 

5.06 

10.20 

7.26 

8.87 

8.87 

10.49 

13.32 

9.32 

7.93 

12.88 

9.58 

11.80 

9.09 

10.64 

10.37 

8.15 

10.18

iserve th

.45 

2.08 

1.05 

2.13 

.98 

4.17 

1.69 

2.24 

1.27 

2.36 

2.47 

2.73 

4.78 

3.19 

1.58 

1.84 

4.00 

2.90 

1.77 

4.18 

1.74 

3.51 

1.09 

3.33 

1.95 

2.16 

.83 

3.10 

2.33 

1.22 

1 17 

1.99 

2.34 

1.35 

2.25 

1.47 

1.43 

.91 

.94 

1.27 

1.45 

.92 

1.43 

.80 

.97 

.97 

1.00 

1.46 

.65

e "air-d

3.65 

3.68 

3.68 

3.68 

3.72 

3.77 

3.77 

3.78 

3.78 

3.82 

3.83 

3.83 

3.85 

3.91 

3.92 

3.95 

3.95 

3.95 

3.96 

3.97 

3.99 

4.08 

4.08 

4.08 

4.08 

4.17 

4.18 

4.18 

4.24 

4.27 

A. sn 

4.31 

4.35 

4.37 

4.38 

4.42 

4.45 

4.47 

4.48 

4.49 

4.50 

4.52 

4.54 

4.57 

4.61 

4.62 

4.62 

4.64 

4.65

ried" basi

7,

6,

7,

7,

7,

6 7, 

7,

7,

7,

7,

7,

7,

7.

7,

7,

7,

7,

 7,

7,

7,

7,

*>7

7,

7,

7,

7

7

7

7

7

7.

7'

7

7'

7

7

7

7

7

7,

7

7

7,

7,

7

7

7,

7,

7,

s of 
TABLE 2. The coals of Table 1 , shoioing moisture-free hydrogen and oxygen; fixed carbon in pu

ratios; "available" hydrogen; and variance from, C: (0+ash) ratio a

No.

201 

202 

203 

204 

205 

206 

207 

208 

208a 

208b 

208c 

209 

210 

210a 

211 

211a 

212 

213 

214 

215 

215a 

216 

216a 

217 

218 

219 

220 

221 

222 

223 

224 

225 

226 

227 

227a 

228 

?29

Designation of coal.

W. Va. 16...............

Pa. 19. ..................

Mo. 4. ...................

Ky.lB..................

W. Va. 2................

Ark. 7A. ................

Tenn. 2..... .............

W. Va. 4B...... .........

Wyo. 4303. ..............

Colo. 4010. ...............

W. Va.23A..............

Va. 6....................

Ala. 3745................

Pa. 9....................

W. Va. 11...............

Pa. 11...................

W. Va. 15...............

Wyo. 4299...............

W. Va. 4................

Ala. 3771................

Va. 4....................

Va. 2B ..................

W. Va.l................

Pa. 10...................

Va. 1 ....................

W. Va.20........

W. Va. 8.... ............

Ky. 6....................

W. Va. 17...............

Pa. 5....................

Pa. 16............ .

Ala. 3769.............

Pa. 20...................

Ky.l.. ..................

N.

1.53 

1.42 

.75 

1.73 

1.37 

1.32 

1.81 

1.60 

1.31 

1.56 

1.69 

1.45 

1.33 

1.13 

1.39 

1.50 

1.29 

1.04 

1.45 

1.44 

.85 

1.50 

1.53 

1.35 

1.45 

1.55 

1.59 

1.27 

1.37 

1.38 

1.48 

1.41 

1.55 

1.33 

1.25 

1.16 

1.85

S.

1.26 

1.08 

5.55 

1.16 

3.50 

2.12 

1.01 

1.10 

.94 

.45 

1.10 

1.24 

1.27 

.88 

2.01 

1.38 

2.09 

.53 

1.19 

2.56 

.71 

.90 

.44 

.81 

.94 

.90 

1.28 

1.23 

1.41 

.92 

.58 

1.49 

.89 

1.65 

1.10 

2.96 

1.24

H(-H2 0).

4.66 

4.81 

5.17 

4.89 

4.93 

3.42 

4.98 

4.37 

4.81 

5.03 

4.76 

4.95 

4.37 

4.82 

3.60 

5.06 

3.94 

3.94 

4.94 

4.91 

5.32 

4.74 

4.94 

4.86 

4.92 

5.11 

4.99 

4.98 

4.96 

4.98 

5.02 

4.40 

5.04 

4.42 

4.83 

4.50 

5.15

C.

76.09 

76.25 

72.45 

75.89 

74.44 

76.37 

75.97 

76.72 

76.84 

77.05 

76.64 

76.57 

77.21 

77.40 

77.29 

76.63 

77.42 

79.12 

77.32 

76.52 

78.19 

78.21 

78.67 

78.56 

78.51 

78.31 

78.16 

78. 47 

78.39 

78.75 

78.94 

78.95 

78.78 

79.00 

79.16 

78.23 

78.31

O (-H3 0).

6.48 

6.86 

5.46 

6.22 

6.40 

3.38 

7.25 

4.48 

10.81 

8.38 

6.14 

6.50 

4.87 

7.80 

2.22 

8.05 

3.14 

3.07 

6.41 

4.82 

9.05 

5.24 

6.81 

7.60 

7.01 

6.41 

6.40 

7.50 

4.93 

5.01 

8.17 

4.42 

6.16 

5.05 

7.39 

1.80 

7.09

Ash.

8.76 

8..C 7 

5.23 

8.54 

7.90 

12.29 

7.03 

10.38 

3.23 

6.32 

8.48 

7.71 

10.30 

6.30 

12.21 

5.31 

11.63 

11.50 

7.33 

8.63 

3.48 

8.43 

5.75 

4.42 

5.69 

6.37 

6.25 

4.85 

8.20 

7.36 

2.82 

8.33 

6.11 

8.19 

4.65 

10.93 

4.44

H2 0*

1.22 

1.01 

5.39 

1.57 

1.46 

.60 

1.95 

1.35 

2.06 

1.21 

1.19 

1.58 

.65 

1.67 

1.28 

2.07 

.50 

.80 

1.36 

1.12 

2.40 

.98 

1.86 

2.40 

1.48 

1.94 

1.33 

1.70 

.74 

1.60 

 2.99 

1.00 

1.47 

.36 

1.62 

.42 

1.92

C

O+ash

4.66 

4.67 

4.68 

4.69 

4.70 

4.71 

4.76 

4.77 

4.84 

4.88 

4.88 

4.90 

4.90 

4.96 

4.96 

5.04 

5.09 

5.17 

5.17 

5.29 

5.33 

5.37 

5.53 

5.55 

5.59 

5.60 

5.64 

5.66 

5.68 

5.71 

5.78 

5.78 

5.80 

5.83 

5.87 

5.90 

5.91

o 

' 
230

011

231 a

231 b

232

233

234

235

236

?37

238

239 

23<ta

239b

240

241

242

242f)

243

244

246

?47

24R

249

250

Pa. 15B. ................

W. Va. 18...............

W. Va. 9....... .........

W. Va. 21 ...............

Ala. 6...................

Ark. 2...................

Pa. 15...................

Pa. 18.. .................

W. Va. 14............... 

Ark. 3174................

Pa."L"... .............

W. Va. 7................

Md. 2 ...................

Ind. T. 9................

Ala. 3770. ...............

Va. 3....................

Pa. 8....................

W. Va. 13.... ...........

W. Va. 12A .............

W.Va. 12. ..............

W. Va. 0................

W.Va. 19...............

W. Va. 10. ..............

1.18

1 d^

1.33

1.83

1.63

1.61

1.52

1 d^

1.40

1.17

1 9°.

1.56 

1 49

1.05

1 49

1.C8

1.55

1.63

1.29

1.36

1.34

1.33

1.70

1.61

1.07

4.06

.68

.67

.52

.80

69

1.35

.63

1.90

3.88

1.55

1.06

2

8=

2 29

1.20

.86

1.24

.49

.68

.97

91

69

.85

66

91

.57

A. Od

4.77

5.09

4 V7

4.93

4.81

5.04

4

7 =

4.39

4 49

4.92

3 

Oft

3 Q7

4 3ft

4.46

4

OQ

5.20

4 94

4.30

5.02

4 OQ

4.85

4.63

4 

CO

4

C1

77.52

7Q ftA

7Q ^fi

79.77

79.35

79.67

79.15

80.25

78.61

80.74

- 80.73 

80.48

81.10

82.41

QO OQ

82.06

82.09

82.16

83.11

82.65

00 ftQ

83.18

go aty

83.56

85.91

1 Q7

6 25

8 

ftQ

3

Q1

7 Qi

6.50

2

K.A

1.52

2 

no

6.30

1 CLO

2.42

5

1 Q

2 77

1 69

5.55

5 14

2

07

4 07

2.48

1 64

3.66

3 

CO

2 66

10.55

5 92

0 01

6.79

3 SI

6

OQ

9 34

10.09

8.63

3.38 

9 27

8

01

5.09

7 29

8.41

3 R4

4.58

6

00

4.01

6 95

6.22

5 no

ciO

4.63

.48

1 OQ

1 £.9

.76

1.01

1 60

.85

.74

34

OQ

2.05

1Q

64

.76

.74

64

1 9R

Q7

.63

1.17

go

1 Q°.

64

.68

.65

5.98

5

QQ

6. 01

6.03

6.03

6.10

6.19

6.26

6.38

6.60

6.81

7.01

7-10

7 =.9

7.68

7 fiQ

7 70

7 ft0.

8

1 A

8

09

8

OQ

8 Aft

8 97

9 01

U 7ft

7 

7 

7 

7

7 

7 

8,

7 

7

8,

7

7,

8,

8 

7

8 

Q 

8,

8,

8

8 

8,

* Moisture (H20) is included as a separate percentage to conserve the "air-dried' 

<» Coals more or less weathered.

basis o
34 THE EFFECT OF.OXYGEN IN COAL.

The slight recalculation of the analyses shown in this table offers 

the data necessary for the observation of the relative amounts of 

hydrogen and oxygen assumed to be in actual hydrocarbon compounds; and these, as well as the relative amounts of volatile carbon 

(total carbon less fixed carbon) are made available for'comparison as 

ratios, H:0 and VC:C, without further departure from the air-dried 

basis of the analysis. The fixed carbon of the proximate analysis 

not only shows marked local variations, but also is subject to considerable error in the process of determination. By combining the volatile carbon in ratio with the more constant and accurately determined 

total carbon, following the method employed by Professor Parr,a the 

fixed carbon error of the proximate analysis is minimized.

The criteria for the study of the composition of the fuels are advantageously supplemented by the calculation of the fixed carbon in "pure 

 coal" (ash and water free) by the method recommended by Professor 

Grout.6 By this method the fixed carbon in "pure coal" is determined by dividing the fixed carbon by the sum of the fixed .carbon 

and "volatile combustible matter" as given in the proximate analysis. 

For use in comparison the variance of the ascertained calorific value 

from the curve value is noted for each coal; also the amount of available hydrogen.

COMPENSATED CALORIFIC VALUES.

It may be of interest to remark at this point that the C : (0 + ash) 

ratios, if recalculated on the moisture-free basis of the oxygen as 

given in Table 2, fluctuate widely from the ratios in Table 1; but if 

the calories also be recalculated to compensate for the eliminated 

water weight that is, if the ascertained calories on an air-dried basis 

be divided by 100 minus moisture in air-dried coal we shall have 

corresponding new theoretical efficiencies in larger denomination.

On referring the new ratio to its serial position higher in the scale of 

the old ratios it will generally be found that the compensated calorific 

value will again fall near its proper, though entirely new and different, 

position in the succession of calorific values. For example, the C: (0 + 

ash) ratio of No. 25, when computed from the moisture-free oxygen 

of Table 2, will be found to be 3.23 instead of 1.73; and the air-dried 

efficiency of 5,753 calories is changed to 6,989 calories when compensated for a loss of 17.69 per cent weight of moisture. Inspection of 

the ratio series in Table 2, or of the curve, shows that a coal having 

a ratio of 3.23 should have an efficiency of approximately 7,000 

calories.

A few other examples, taken at random, of coals having high moisture may be presented. No. 64 of the tables, a New Mexico Cretaceous coal, whose ratio is 2.28, its efficiency error being very small, 

has a moisture of 10.86 per cent.. On the moisture-free basis the

oBull. Geol. Survey Illinois No. 3,1906, p. 31. & Econ. Geology, vol. 2,1907, p. 240.
OXYGEN AND ASH AS IMPURITIES. 35

ratio of this coal becomes 3.46 and the compensated efficiency 7,127; 

by reference to the curve or to the proper point in the succ'ession of 

the ratios in Table 2 it will be seen that the calorific value of a coal 

having a ratio of 3.46 should be about 7,137. In other words, this 

coal, whose curve error was + 6 on the air-dried basis, appears to have 

an erVor of +10 when projected on the moisture-free basis among the 

high-grade bituminous coals of Tennessee, Ohio, and Pennsylvania. 

Another coal having relatively high moisture content in its air-dried 

condition is No. 144 of the tables. This coal from Wyoming has a 

moisture content of 6 per cent and a ratio of 3.20, its efficiency error 

being 30; on the moisture-free basis the ratio of this coal becomes 

4.23, the compensated calories becoming 7,399. Passing up the scale 

of the ratios it appears that a coal having a ratio of 4.23 should have 

a calorific value of a little less than 7,430; so that this coal which had 

a deficiency of 30 on the air-dried basis, when projected as moisturefree with a higher ratio, shows a deficiency of about 80 calories in its 

new position on the curve. No. 203, a Paleozoic coal from Missouri, 

with moisture 5.39 and a ratio of 4.68, has an error of 120 calories, 

probably due to the very high sulphur. The moisture-free ratio of 

this coal is 6.78, the compensated calories being 7,944. The calorific 

value for a coal having a ratio of 6.78 should, according to the curve, 

be not far from 8,030; so that the error when this coal is projected 

on the moisture-free basis to a position among the highest grade semibituminous coals becomes 85 calories instead of 120, as developed 

on the air-dried basis. Again, No. 32, a Laramie coal from Lafayette, 

Colo., has a moisture of 13.39 and a'ratio of 1.95, its variance from 

the curve being 45 calories; the r^tio on the moisture-free basis 

for this coal is 3.17, the recalculated efficiency being 6,929. Passing 

down the columns to No. 142 we find that the efficiency for a coal 

with a ratio of 3.17 should be 6,970, showing an error of 41; in other 

words, this coal, which had an error of 45 in its normal air-dried 

condition, has almost the identical error when recalculated to eliminate the moisture and referred to a new position very much higher 

in the curve.

VALUE OF MOISTURE-FREE DATA.

Comparisons of this kind are of value chiefly as indicating the consistent progression of the ratios and. the stability of the curve as 

applied both to moisture-laden and to moisture-free coals. The dry 

coals fall in the same scale as the air-dried and with nearly equal 

precision. For the entire series of coals in the table the average total 

for the carbon, oxygen, and asn is about 91.82. It is perhaps permissible to interpret this agreement of the moisture-free ratios and 

compensated values as indicating approximate equivalence in anticalorific' value for the oxygen of the moisture and the oxygen of the 

coal itself, -as well as for the ash.
36 THE EFFECT OF OXYGEN IN COAL.

An inspection of Table 2 shows that in many coals of the same 

ratio and of nearly equal efficiency there are striking differences in 

the amounts of fixed carbon (in pure coal), and a wide range in the 

H:0 ratios, the latter being also apparent with respect to coals with 

the same percentage of fixed carbon. Similarly a less noticeable 

fluctuation is seen in the relations of the VC:C ratios both in coals of 

the same efficiency and in those of equal fixed carbon. The vTariations thus disclosed appear, in some instances, to explain the departures of the ascertained efficiencies from the calorific values indicated 

by the ratio curve.

The data in this table offer not only a better opportunity to study 

the relative values of oxygen and ash, since the oxygen is restricted 

to that assumed to belong to the coal itself, but also a basis for considering the comparative anticalorific importance of the oxygen of 

the moisture in the air-dried samples tested. The latter question 

becomes, under the circumstances, largely a matter of observation 

of the effects of the varying percentages of oxygen, ash, and moisture, in a miscellaneous and somewhat heterogeneous aggregate of 

coals.

The relative values of these impurities may be more precisely 

estimated if the coals are grouped as to kinds and districts, rather 

than merely by the ratio sequence, and each kind is studied by itself. 

Possibly, also, new and slightly modified curves will be found in 

groups of this sort.

RELATIVE NEGATIVE VALUE OF ASH AND OXYGEN.

The question whether oxygen or ash is negatively more potent is 

difficult to determine from the comparison of so wide a range in 

kind, condition, and age of coals. The difficulty is further complicated and rendered more delicate -by the fact that so many of the 

errors or variances from the curve lie within the range of error in the 

work of the calorimeter, the average ratio-curve error for the total 

number of analyses being very much less than 1 per cent of the average calorific value. The question is therefore, for the present, left 

somewhat in doubt. From study of the tables, however, I am inclined 

to believe that the oxygen is possibly of slightly greater anticalorific 

importance in the lowest grade of bituminous and the subordinate 

group of coals, while in the higher bituminous and the semibituminous 

fuels the ash is probably of greater negative value. From a casual 

glance it would appear that in the air-dried samples the greater 

anticalorific value lay in the oxygen. f But the possibility that many 

of these coals have taken up oxygen under exposure to air or weathering conditions enjoins caution in forming conclusions; for, as I shall 

indicate later, the oxidized coals are generally characterized by deficiencies, as compared to the curve, in calorific value. On the other
OXYGEN AND ASH AS IMPURITIES. 37

hand, the arrangement of the coals is such that the slightly greater 

available hydrogen prevalent in the coals with high ash (on account 

of their generally higher class) may be regarded as counterbalancing 

a small margin of the disadvantage attributable to the ash, thus 

appearing to indicate for the ash a slightly greater anticalorific 

value. However, the number of instances of parity of coals with 

alternating percentages of the two impurities, in which no unusual 

available hydrogen accompanies the high ash, is so great as to preclude any important difference of negative value in favor of the 

ash. But it will be observed in passing down the columns of the 

table that coals with high hydrogen are usually accompanied also by 

high sulphur, whose diluent influence i:i the analysis tends to neutralize the effect of the high available hydrogen. Thus it becomes 

more readily practicable in general to treat the hydrogen as constant, 

and so to ignore it, along with the nitrogen and sulphur, in forecasting the calorific values of the fuels by means only of the C: (0 + ash)

ratios.

On the whole, the calorimetric tests make it evident that high 

oxygen (with its usually slightly lower available hydrogen concomitant) and high ash (in most cases accompanied by slightly 

higher available hydrogen) counterbalance, so that practically, 

taking coals as they come, the calorific values of two coals in which 

the two great impurities alternate, carbon being constant, are almost 

exactty equal. The facts presented in the tables show plainly and 

conclusively why the Paleozoic coals o;: the Eastern Interior basin 

can not possess the efficiency of Appalachian standard coals of the 

same ash percentage; and why the very low-ash, but high-oxygen 

samples of low-class, subbituminous, and lignitic coals of the Cretaceous or Tertiary exhibit a calorific efficiency no greater than that of 

high-class Paleozoic coals having contrastingly high ash and correspondingly low oxygen, if the total carbon is the same.

It will later be shown that some of the maximum variations in the 

available hydrogen are responsible for &, number of the larger variances from the ratio curve in Tables 1 and 2. The latter are not, 

however, sufficiently numerous or large to require a coefficient for 

compensation.

It is probable that for a group of camels and bogheads in which 

the hydrogen is excessively high a higher special cannel curve will be 

found desirable. The construction of such a curve based on the 

ascertained component ratios and efficiemcies will be much simpler, 

and perhaps in general more reliable, than a coefficient for the abnormally high hydrogen of this group.

RELATIVE EFFECT OF THE OXYGEN OF MOISTURE.

The obstacles to distinguishing between the negative values of the 

oxygen of the coal proper and the oxygen of moisture, in the calo-
38 THE EFFECT OF OXYGEN IN COAL.

rimeter results, are largely the same as those affecting the discrimination between the relative values of ash and oxygen. In fact, the effect 

of moisture on the standing of the coals as determined by the C : (O + 

ash) ratios is generally so little as to excite surprise. For example, the 

efficiency shown in the test of No. 31, a Fort Union coal from Deer 

Lodge, Mont., which has 9.05 per cent moisture, or No. 32, theLaramie 

coal at Lafayette, Colo., with 13.49 per cent of moisture, differs less 

than 1 per cent from the efficiency of No. 30, the Pocahontas bone at 

Gary, W. Va., which has but 0.52 per cent moisture. Other coals, 

such as Nos. 71, 72, and 72a, afford similar striking contrasts, the 

calorific values being so little affected and so regularly conformable 

to the curve as to make it clear that no great difference can exist 

between the negative values of the oxygen of moisture and .that 

combined in the coal.

In connection with this question of the relative values of the two 

oxygens attention should be called to the approximate coincidence 

and complete conformity of the ratios of the moisture-free coals and 

of their respective compensated calorific values with the curve of the 

air-dried coals, as noted on page 34.

A review of the efficiency variations in Table 2 tends to show 

slightly more frequent calorific deficiencies in coals having abnormally 

high moisture. But, on the other hand, allowance must be made 

for the fact that most of the samples very high in moisture are low in 

the scale of coal formation, and consequently most susceptible to 

deterioration on exposure to atmospheric oxygen. There is no 

doubt in my mind that many such deficiency variances are due to this 

cause. Furthermore, so many of the instances of calorific deficiency 

which might perhaps correctly be ascribed to high moisture are 

attendant on unusual deficiencies in the available hydrogen, that at 

the end one is left uncertain whether, so far as may be judged by 

the behavior of the air-dried samples in the calorimeter, the moisture 

oxygen in general differs much from other oxygen in its ha'rmful 

effect. This does not, of course, preclude the recognition of a difference under practical boiler-grate conditions.

The varying capacity of coals of the same age and district, under 

apparently the same conditions as to progressive metamorphism, to 

hold water seems to depend largely both on the character of the 

original constituent organic matter and on the conditions governing 

the first or biochemical stage of coal formation.

Since coals with high oxygen and low ash have the same calorific 

values as others in which the terms are reversed, if the other percentages are constant, it becomes evident that, in general, the carbonoxygen ratio of the coal (ash free, or ash constant) corresponds fairly 

closely to the rank of the coal in efficiency. The same ratio also indicates, for coal of the same origin, its progress in the scale of coal 

transformation.
OXYGEN AND ASH AS IMPURITIES.

39'

ESTIMATE OF THE EMPIRICAL ANTICALORIFIC VALUE OF

OXYGEN,

NEGATIVE VALUE OF OXYGEN AND ASH.

In the preceding pages it has been shown that, in general, throughout a miscellaneous collection of coals of all grades, the heating value 

of the fuel is roughly indicated by the amount of the total carbon 

as compared to the sum of the oxygen and ash. Also that, so far as 

concerns the calorific efficiencies of the coals, alternating amounts 

of oxygen an'd ash essentially offset each other, providing the total 

carbon be constant, though strictly speaking a slight excess of negative potency appears to lie in the ash. On the whole, however, in 

view of the tendency of two of the assumed constants, sulphur and 

hydrogen, to compensate each other, as will be pointed out in the 

next section, we may conclude that, from the practical standpoint, 

oxygen and ash may be regarded, according to the calorimetric tests, 

as essentially interchangeable.

APPLICATION OF THE CURVE.

The curve platted from the C : (0 + ash) ratios and the calorific 

efficiencies provides an indirect method of ascertaining the average 

. amounts of calorific change corresponding to any given ratio change, 

.for different parts of the curve. For any one length or section of 

the curve the amount of this calorific change may be taken as a 

scale of approximately equal units, by which any fractional ratio 

change may be measured. Hence it is not difficult roughly to estimate the anticalorific values of 1 per cent added to or subtracted 

from the oxygen or ash in a coal analysis.

Inspection of the curve, as provisionally drawn, shows the following approximate values of curve segments covering changes of 0.05 

and 0.01 in the ratios (horizontal component) at a number of points:

Calorific changes corresponding to ratio changes of 0.05 and 0.01 at stated points in curve.

Part of curve.

Ratio.

1.00

1.50

2.00

2.50

3.00

3. 50

4.00

4.50

5.00

5.50

6.00

Ratio change 

0.05.

Calories.

115.0

80.0

50.0

40.0

35.0

28.0

22.0

19.0

13.3

10.0

8.0

Ratio change 

O.OL

Calories.

23.0

16.0

10.0

8.0

7.0

5.6

4.4

3.8

2.6

2.0

1.6
40 THE EFFECT OF OXYGEN IN COAL.

FLUCTUATION IN EFFECTS OF CHANGES.

The practical application of these units at once discloses wide 

fluctuations in the relative effects of changes of 1 per cent in the joint 

impurity. These are due (1) to the constantly changing elements 

upon which the ratios are based, and (2) to the marked difference 

between the ratios as a curve component, with constantly progressive 

dividends and divisors, and the component of the efficiencies. . The 

essential result is an increase in the negative value of the impurities 

in passing from one part of the curve to another, as the following 

figures show:

At ratio 1.00 the value of 1 per cent of added oxygen or ash is about 

47.5 calories; at ratio 1.50 the value of 1 per cent of added or subtracted oxygen or ash averages approximately 64.5 calories; at 2.00 

the average approximates 65.4 calories; at 2.50 it approximates 78 

calories; at 3.00 it approximates 92 calories, the effect becoming more 

strongly marked in sub traction; at 3.50 it averages about 97 calories; 

at 4.00 the variation between the added and the subtracted 1 per cent 

is slightly greater, the average of both at that point being about 93.9; 

the decline is still more marked at 5.00, where 1 per cent of the joint 

impurity is valued at nearly 82.2 calories, while at 5.50, its effect is 

about 77 calories; and at 6.00 it falls to about 72 calories. At this 

point (ratio 6.00) deduction of 1 per cent of the impurity amounts 

to an addition of about 77.6 calories, while addition of the same percentage causes a change of about 69 calories. These values are based 

in each case on the average of the differences between the ratios in 

Table 1 and those obtained by adding 1'per cent and by subtracting 

1 per cent from the total oxygen plus ash.

ESTIMATE APPLIED TO THE ANALYSES.

A clearer idea of the application of this indirect method may 

easily be gained by practical experimentation with the analyses in 

the table, the ratio changes resulting from increase or diminution 

of the impurities being compared with the calorific differences indicated by the corresponding changes in the curve. For example, No. 

145 of Table 1 has a ratio of 3.21, the corresponding efficiency being 

6,990 calories. The addition of 3 per cent of oxygen or ash to this 

coal produces a coal whose C: (0 + ash) ratio will be 2.82. The calorific 

value of a compensated coal having this ratio will be found to be 

about 6,750 calories, showing a difference of about 240 calories on 

account of the addition of 3 per cent of oxygen, the impairment averaging, therefore, about 80 calories to each 1 per cent of added impurity. If, on the contrary, we subtract 3 per cent from the oxygen or

ash of the coal in No. 145, we shall have a coal with a ratio of 3.72, ^ whose efficiency, according to the curve, will be about 7,260 calories,
OXYGEN AND ASH AS IMPURITIES. 41

an increase of approximately 270 calories, as the result of deducting 

3 per cent of impurity; that is, 90 calories to each 1 per cent. Or, to 

take another example at random, No. 183 in Table 1, with a ratio of 

4.31, has a calorific curve value of 7,515. The addition of 3 per cent 

of: oxygen or ash produces a coal with a ratio of 3.67, whose efficiency 

will be approximately 7,238 calories, a calorific difference of 277, 

being approximately 92 calories to each added 1 per cent of the joint 

impurity. Contrariwise, the subtraction of 3 per cent in the analysis 

of No. 183 defines a coal having a ratio of 5.21, according to which the 

calorific value of the coal will be 7,780, showing a difference of approximately 265 calories resulting from the difference in the impurity, or 88 

calories as the average advantage derived from the elimination of 1 

per cent of the impurity.

Tests of this kind may be applied to all of the coals in the table. 

They are, however, inaccurate and of little value, though interesting. 

The fluctuations are very wide and vary from the amounts calculated

from the value of the combustible displaced or concentrated by the 

addition or subtraction, respectively, of the inert impurity.

CAUSES OF VARIANCE FROM THE CURVE. 

GENERAL STATEMENT.

The causes of the wider fluctuations of the ascertained efficiencies 

from the C:(0 + ash) ratio and efficiency curve appear in most cases to 

lie in the percentages of those elements that have been ignored as 

negligible constants, hydrogen, sulphur, and nitrogen. Besides 

these we have, also, among the data of the analysis the less definite, 

though no less absolute, effects of (1) oxidation by weathering and (2) 

the devolatilization incidental to anthracitization. There are, however, other causes which seem incapable of detection from the mere 

ultimate analyses. Although of subordinate importance, these will 

first be considered.

+

CAUSES NOT SHOWN BY ULTIMATE ANALYSES.

First are the differences in the hydrocarbon compounds entering 

into the substance of the coal. These compounds, whose number and 

structure appear still to be largely, unknown, presumably vary in 

stability, in quantity, and more or less in calorific values. Some of 

these differences are probably due to the nature of the original ingredients. The bogheads, for example, are described as largely composed 

of the remains of gelatinous algse, which appear to have exercised a 

selective attraction for certain bituminous compounds, and which are 

excessively rich in volatile combustible having an illuminating value 

far above that derived from ordinary gas coals. Pyropissite, which 

is largely composed of resins, is an extreme example in this category.
42 THE EFFECT OF OXYGEN IN COAL.

 I-.

The obviously abundant resin in some of our Cretaceous low-grad$ a 

bituminous and subbituminous coals and lignites doubtless contributes to the calorific excess which attends many of the unweathered 

samples. A number of these coals figure among the extreme excess 

variances among the efficiencies marked "L" to the left in the curve 

diagram, Plate I.

Another, possibly the principal, of the intangible causes not 

revealed by the analyses is the error in oxygen determination in the 

process of making the ultimate analysis. Since the oxygen is the 

residual of the analysis, ascertained by subtracting from a total of 

100 per cent the sum of the percentages of the other elements, it 

is evident that it contains the residual error which may possiblybe cumulative. Among the lower ratios a slight error in oxygen 

determination does not cause a very marked effect on the calorific variance, but in the higher grade coals a fraction of 1 per 

cent may make a considerable difference in the ratios, and a consequent erroneous indication of the efficiency. In a coal having a 

ratio of 2.00 an error of about 1 per cent of oxygen in the analyses will 

amount to a curve difference of about 63 calories. It is possible that 

the surprisingly low oxygen of several of the semibituminous coals 6 

may in part be due to error in its determination.

An important source of error in oxygen determinations is connected 

with the presence of pyrite in the coals, for the production of sulphur 

dioxide causes an oxygen deficiency equal to three-eighths of the sulphur in the pyrite. The residual error (oxygen) of the analysis is 

also affected by the reduction of iron carbonate when that is present 

in the coal, the results being too high carbon and oxygen and too low 

ash. Small errors in oxygen calculations are also due to the recognized tendency in high-ash coals of the aluminous silts to hold back 

hydrogen and of siliceous sediments to withhold oxygen. The relatively few cases in which the marked variances are not fairly well 

explained by these or other causes, and in particular the very small 

average error of the efficiency curve, indicate a high standard of 

accuracy in, the coal analyses on which this report is based.

As a third cause of variance not visible in the analyses is the oxygen 

taken up on exposure to the air or weathering, which constitutes a 

serious cause of variance on the side of deficiency. This matter will 

be again referred to (p. 63) in connection with the subject of the 

weathering of coals.

CAUSES RECOGNIZABLE IN ANALYSES.

The causes of variance that may, frequently at least, be recognized 

in the analyses will now be considered.

o By low grade is meant only less advanced in the process of coal formation. 

<> Nos. 228,230, and 237.
OXYGEN AND ASH AS IMPURITIES. 43

VARYING AVAILABLE HYDROGEN.

In Table 2 the proportions of hydrogen are shown both by means of 

its ratios with the oxygen in moisture-free coal, and as "available"

hydrogen ( H -^- Y As might be expected, a number of the large

errors seem to be explained by the relatively very large or very small 

percentage of hydrogen. Yet the evidence is not free from conflict, 

since in numerous analyses a high available hydrogen is shown without any corresponding error of excess calories; in others calorific 

excess attends a relatively low hydrogen. As coals in which the 

excess of calories would seem to be due to high hydrogen, citation 

may be made of Nos. 7, 21, 33, 36, 43, 52a, 86, 126, 168, 208b; and 

247. Compare also Nos. 23, 38, 51, 53, 79, and 130. Several of 

the coals cited, however, are very low in sulphur, which, by reducing 

the amount of the negligible constants, enlarges the space for the other

elements, especially carbon, and so .promotes a higher efficiency for 

the fuel. There are on the other hand but few samples in which 

the lack of hydrogen seems clearly accountable .for deficiency of 

calories. Probably of this sort are Nos. 19, 106, 112, 135a, 144, and 

246. The low curve efficiencies of Nos. 163,181,190, 206, 211, and 236 

are also possibly due to low hydrogen,- though in these coals (marked 

"S" in PI. I) which are undergoing anthracitization the volatile 

carbon likewise is very low; and since,.in some of the advanced coals, 

an abnormally low volatile carbon appears to be a cause of calorific 

deficiency, it is possible that most of the coals last cited may be 

impaired by loss of volatile carbon as well as of hydrogen. a Outside 

of the semi anthracites and more advanced semibituminous coals 

there do not seem to be many coals in the tables whose lack of calories 

is possibly traceable to low hydrogen. In Nos. 84, 93, HOa, 171c, 

and 196, the calories are high in spite of the low available hydrogen; 

while in No. 2b there is no available hydrogen at all, but on the contrary a deficiency of 0.37, yet the efficiency-curve error is but 150 

calories. High efficiency with a relatively low available hydrogen is 

a common characteristic of the unweathered younger and less altered 

coals, in which the diluent sulphur is low. It is to be remembered 

that the efficiencies and errors here discussed relate to the ratio curve, 

and not to those calculated from Du Long's formula.

The number of coals in which a relatively high available hydrogen 

or H:O ratio is attended by a calorific deficiency, instead of excess, 

is surprisingly large. Examples are Nos. 27, 48, 56, 105, 138, 203, 

215, 228, 237*, and 238. (See also Nos. 40, 74, 76, 153, 158, 162, 164, 

178, 185, 197, and 215.) Several of these coals have high sulphur, 

whose double effect is not fully overcome by the relatively high

a The relative values of both VC: C 'ind H : O in the coals arc better shown in Plate III than in Table 2.
44 THE EFFECT OF OXYGEN IN COAL.

hydrogen, as will presently be illustrated. Samples Nos. 228, 237, 

and 238 have abnormally low volatile carbon and very low oxygen; 

to the former -the deficiency is probably due.

On the whole it may be said that while high available hydrogen 

tends to cause curve variances on the side of excess, there are comparatively few coals in which its effects are not so far neutralized by 

a high sulphur content, or (in case of very low sulphur) by an enlarged 

proportion of carbon or, perhaps, by a very high ash (Nos. 27 

and 65), as to reduce the excess error to less than 100 calories. 

There appear to be 10 coals whose excess error of over 100 calories 

seems more or less distinctly due to the high available hydrogen. 

For the cannel-boghead group, whose hydrogen is characteristically 

greatly in excess, a higher curve should be drawn. The average 

total hydrogen in the 319 air-dried samples in Table 1 is 4.92 per 

cent.

SULPHUR.

In many respects sulphur is the most important of the neglected 

elements affecting the accuracy of the ratio-efficiency curve. Although the errors on account of this ingredient are generally slight, 

usually less than 1 per cent of the calorific value, its effect is no doubt 

relatively important in many cases.

In combustion the heat values of sulphur are generally recognized 

as depending on the state or condition in which it occurs. As free 

sulphur it is comparatively harmless and may exert its full theoretical 

calorific efficiency; in pyrite, niarcasite, or other sulphides, its heat 

contribution is greatly lessened by the fact of combination, and also 

differs with the surrounding conditions; in sulphates, whether infiltrative, interstitial, or in the form of scales in the joints and cleavage 

planes of the fuel, it is a dead load to be borne at the expense of the 

other fuel elements. Unfortunately information as to the state of

the sulphur in the samples tested and analyzed is unavailable for this 

report ; a so that I am obliged to ignore the differences in the effects 

of the different kinds, and regard only the apparent influence in general and as a whole when the sulphur is in large or exceptionally small 

percentages.

Since the efficiency of the coals is very closely controlled, as has 

been shown, by the balance between the carbon and the two chief 

anticalorific elements, oxygen and ash, the sulphur, as well as the 

nitrogen and hydrogen, has in the preceding pages been treated as 

constant. But as a matter of fact, while the hydrogen and nitrogen 

appear to be constant in kind, differing only in quantity, the sulphur 

differs greatly both in quantity and in kind or effect. In the series 

of analyses shown in the tables the sulphur ranges, on the air-dried

a In most of the high-sulphur coals of the Eastern Interior basin the sulphur is probably chiefly in the 

form ot sulphides.
OXYGEN AND ASH AS IMPURITIES. 45

basis, from a minimum, of 0.22 per cent in No. 52b from Wyoming, 

to a maximum of 8.33 per cent in No. 138 from Kansas. Its average 

percentage in the 319 coals is 2.13.

Since sulphur even in its best condition has a smaller calorific value 

than.carbon, it is plain that any unusually high percentage of it, unless compensated by increased available hydrogen, another of the 

constants, virtually dilutes the combustible of the" coal and causes a 

falling off in its efficiency. Therefore a comparison of the analyses 

in the tables with reference to sulphur is necessarily chiefly confined, 

since we are not cognizant of the state of the sulphur in each sample,. 

to the diluent effect in some of the coals of an abnormal proportion of 

this inferior combustible, and the effect of comparatively low sulphur 

in others. Accordingly, the practical and main purpose of the study is 

to observe the amount of the error or variance from the ratio-efficiency 

curve in consequence of unusual fluctuations in the sulphur percentages. As examples in which deficiencies in ascertained calorific value, 

as compared with the curve indications, are probably due to unusually high sulphur, may be cited Nos. 48, 65, 76, 80, 94, 96, 102, 

138, 157, 185, 230, and 237 in the table. The errors in most of these 

cases are, however, small. The diluent effect of a difference in 

sulphur may in many coals be roughly approximated by rating the 

unit sulphur effect at the difference between its theoretical value 

(2,250) according to Du Long's formula and the calorific value of the 

unit of the-rest of the coal which it partly displaces. The effect of 

the available hydrogen variation may be calculated at 34,460 according to Du Long's formula.

In passing down the columns it will be noted that as a rule the 

coals that are high in sulphur are also relatively high in hydrogen, 

the highest percentages of the former being usually attended by the 

greatest excesses of the latter.0 The general result is the neutralization of the bad sulphur effect by the high hydrogen. In many cases 

the effect is converted from a deficiency to a small excess. As illustrating analyses in which the sulphur effect is not fully neutralized, 

.comparison may be made of Nos. 9,11, 16, 28,40,48, 55, 58, 63, 73, 74, 

92,105,113,138,142,143,164,178, and 203. Some of these are coals 

with the highest available hydrogen. Two of the most striking are 

No. 138 from Kansas and No. 203 from Missouri. Other instances 

of complete neutralization are Nos. 14, 20, 23, 33, 36, 38, 43, 48, 53, 

69, 66, 79, 82, 98, 99,.147b, 153, 167, 168, 172, and 205. On the other 

hand, it will be noted that the coals with very low sulphur are more 

often accompanied by a low available hydrogen.6 Some of the larger 

efficiency errors on the side of excess are coincident with the exceptional cases of very low sulphur and unusually high hydrogen. Examples are Nos. 21, 52a, 81a, 86, 93, 100, 118, 126, 128, 141, and 161a;

a Examples are Nos. 14, 20, 23, 40, 42-44, 45, 48, 49, 65, 60, 79, 82,147-149,153,185,187, 203, and 205. 

i> This applies to the Cretaceous and Tertiary coals in the tables.
46 THE EFFECT OF OXYGEN IN COAL.

also Nos. 31a, 134,134a, 17la, 173b, and 179a. These fall for the most 

part among the Cretaceous coals, and their superior efficiency is probably connected with the high content of resin.

The review of the analyses with respect to sulphur shows, in general, that except among the fuels approaching anthracitization the 

the coals with highest sulphur usually have the highest available hydrogen, those with lowest .sulphur being usually relatively low in 

hydrogen; and accordingly that in most cases the effect of an excess 

of sulphur is nearly counterbalanced by the presence of an excess of 

hydrogen. Conversely, the effects of unusual proportions of hydrogen are, in general, largely neutralized by a parallel variation in the 

sulphur contents of the coal. These facts explain, in most cases, the 

smallness of the ratio-efficiency curve errors in the presence of the 

greater variations of the available hydrogen. The mutually neutralizing action of the sulphur and hydrogen is the main circumstance 

making it so readily practicable to treat these elements as negligible 

in forecasting the efficiency of the coal solely on the basis of the 

carbon, oxygen, and ash. It should be noted that compensating the 

oxygen for loss with sulphur of pyrite (see p. 42) would by lowering 

the C: (O + ash) ratio tend to reduce the prevailing errors of deficiency 

in high-sulphur coals, while slightly reducing the available hydrogen.

NITROGEN.

Of this, the third and last of the neglected constants, I have 

not attempted a careful study with reference to error influence. 

From a casual inspection of the tables I am inclined to regard it as 

largely eliminated from the peats at an early date in the dynamochemical process, the remainder being, perhaps, mechanically retained 

in a free state, or in an unknown state of combination in the more 

advanced coals. It seems to be practically .passive, and of so little 

range in amount as usually to produce no marked effect as a diluent. Its average percentage in Table 1 is 1.21. The study of the 

effect of nitrogen on the calorific values requires a series of analyses 

including larger groups of peats and of the succeeding low grades of 

coals.

ANTHRACITIZATION.

Both the greatest individual error and the greatest average variance from the curve are found among the highest of the semibituminous coals, which are undergoing anthracitization or in the anthracitic group itself. A glance at the percentages of fixed carbon in 

pure coal in Table 2 shows that nearly all the coals that have a fixed 

carbon of 79 or more are deficient in calories unless they have a high 

volatile carbon (see the VC : C ratios). The maximum variance among 

the 312 coals of the table is in the anthracite culm at Scranton, which 

shows a deficiency of 312 calories from the curve. In many of these
OXYGEN AND ASH AS IMPURITIES. 47

coals the deficiency is probably due to loss of hydrogen, as shown -in 

the available hydrogen column of the table.

Of the 18 coals with as much as 79 per cent fixed carbon and a 

volatile carbon ratio of 9.25 or less, only 2 show excess errors. These 

18 coals (excluding the Rhode Island semigraphite, which is not a 

fuel) are here grouped for better comparison:

Variance from curve efficiency of coals high in fixed carbon and low in volatile carbon.

No.

103

179

140

16?,

211

24?!

239b

?3Pn

30

238

?3fi

228

190

161

181

206

?37

230

Locality.

Coal Hill, Ark..........................

Gary, W. Va. ...........................

.....do..................................

Variance 

from curve.

Calories. -312

-214

- 33

-115

-270

-185

-147

-252

+ 12 -115

-2bO

-224

-106

+ 163 -215

-230

-133

-150

Fixed carbon in pure 

coal.

Per cent. 

91.09

87.01

86.89

86.50

85.18

S4.-29

83.89

83.34

82.87

82.27

81.92

81.41

80 94

80.57

80.45

80.36

79.77

79.23

Ratio 

VC to C.

Per cent. 

1.13

2.93

3.20

4.48

4.65

6.58

5.82

6.65

6.02

7.49

7.96

7.74

9.02

6.73

9.15

7.64

' 9.11

9.07

Available 

hydrogen.

Per cent. 

2.30

3.01

 3.10

3.49

3.50

4.07

3.67

1 3.61

2.83

4.16

3.73

4.28

3.42

3.39

3.26

3.50

4.20

4.02

Sulphur.

Percent. 

0.77

2.14

.66

.70

2.01

1.24

2.29

 2.85

.55

1.55

1.90

2.96

1.51

1.31

1.08

2.12

3.88

4.06

The average error for the 8 semianthracites, with fixed carbon of 

S3 per cent or more in pure coal, is 191 calories. . The average error 

for the 10 highest-grade semibituminous, having a fixed carbon of over 

79 per cent and a VC:C ratio (per cent) of 9.25 or less, is 158 calories. 

If this list of 18 coals be excluded from the table list the average 

error of the ratio curve is but 60.09 calories.

Other high-grade semianthracites which show calorific deficiency 

incidental to loss of volatile are the following:

Variance from curve efficiency of coals high infixed carbon.

No.

?,W

123

182

Locality. Variance 

from curve.

Calories. 

- 92

-100

- 60

Fixed carbon in pure 

coal.

Per cent. 

79.91

79.66

79.25

Ratio 

VC to C.

Per cent. 

9.42

9.40

10.00

Available 

hydrogen.

Per cent. 

3.55

3.36

3.41

Sulphur.

Per cent. 

2.09

1.14

1.27

The last sample has a higher volatile carbon. The VC:C ratios are 

better studied in Plate III, in which the coals are arranged in the 

order of their fixed -carbon in pure coal (ash and moisture free).

On the other hand, among these coals approaching clevolatilization 

it is interesting to note signs that a relatively large proportion of carbon in the remaining volatile is favorable to a higher efficiency. For 

81144 Bull. 382 09 4
48 THE EFFECT OF OXYGEN IN COAL.

illustration: The coal at Sun, W. Va. (No. 240), with a relatively 

high volatile carbon (VC:C= 10.68 per cent) shows an excess of about 

136 calories over the curve, though its available hydrogen, 3.65, is 

0.45 below that of most of the coals near by in the series.0 Relatively 

high volatile carb'on probably assisted low sulphur in Nos. 213, 196, 

and 70, among others. Contrariwise, in Nos. 162, 228, 237, and 238 

low efficiencies accompany unusual diminution of the volatile carbon, 

in spite of the fact that the available hydrogen is fully up to or above 

the normal in these coals. Possibly sulphur may have exercised a 

depreciating influence in Nos. 228 and 237.

These observations seem to indicate that although the calorific 

values in the lower grades of coals do not seem affected by the relative amount of fixed carbon, too great a loss of volatile carbon 

impairs the efficiency of the fuel.

The range of error in the determination of the fixed carbon in a 

coal forbids basing too confident conclusions on a limited number of 

observations.

WEATHERING.

The changes of coal under exposure or weathering are indicated 

in the analyses by reduced H: 0 ratios; by reduced available hydrogen; 

and in many cases by reduced volatile carbon ratios. Illustrations will 

be given later (p. 63) of these changes, invariably showing calorific 

deficiencies except in the high grades of coal. As a matter of fact 

weathering can in most cases be detected by the changes in the 

oxygen-hydrogen relations and by the marked calorific deficiencies.

QUANTITATIVE RELATION OF OXYGEN TO COKING.

SUPPOSED ALGAL INGREDIENTS IN COALS.

SOURCE AND CHEMICAL EFFECTS.

As stated in the introduction to this paper, one of the purposes of 

this comparative study was to ascertain the testimony of the ultimate chemical analyses as to the validity of a previously conceived 

working hypothesis in explanation of the coking property of coals. 

'A few words will outline the basis of this hypothesis:

The brilliant investigations carried on by Renault 6 and Bertrand c 

as to the microscopical structure of a considerable number of bogheads and oil shales of various continents and geologic ages show that 

these rocks owe their peculiar physical and chemical characters 

(which include a relatively high percentage of volatile matter, a

a The estimate of calorific value calculated from the chemical analysis of this coal was 312 calories less 

than the ascertained efficiency. See Prof. Paper U. S. Geol. Survey No. 48,1906, p. 255.

6Eenault, B., Les micro-organismes des combustibles fossiles, St. Etienne, 1903.

"Bull. Soc. d'hist. nat. Autun, vol. 9,1897, p. 193; Trav. et mem. de 1'Dniv. de Lille, vol. 4, No. 21, 

1898; Compt. rend. 8me sess. Cong. g6ol. internal., 1901, p. 453.
KELATION OF OXYGEN TO COKING. - 49

generally high illuminating value, etc.) primarily to the presence 

of immense numbers of supposed gelatinous algae which in these 

coals seem to have exercised a selective attraction for certain bituminous compounds. Algal matter in smaller proportions, and consequently with less distinct resultant characteristics in the coal, is 

found also in the " cannel-bogheads " and some of the "bogheadcannels." The conditions of accumulation and deposition attending 

the origin of many other coals were doubtless favorable for the 

mingling of algae and different animal remains in varying quantities 

with the debris of higher plant types; though their preservation, at 

least in optically recognizable form, is most improbable in any but the 

rarest instances. Yet it is more than probable that the substances 

of these lower organisms, whether completely macerated and disorganized or not, contributed as ingredients to the mass of coal-forming 

material. It is therefore reasonable to admit that though not optically discernible now, or though all their original structure is obliterated, they have probably exerted some influence on the character 

and quality of the final converted organic residuum.

It is not important to discuss in this place either the source proposed by the French paleobotanists for the bituminous " enrichment" of the coal or the time of the bituminization, though, for my 

part, I am disposed to regard the enriching bitumen as derived from 

the decay of associated animal organisms, as well as from the putrefaction products of great quantities of the gelatinous algae themselves. The relatively increasing importance of the bituminous 

matter in the more mature, older, or more altered condition of the 

fuel is due, I believe, to concentration as -the result of devolatilization and reduction of the coal by the dynamochemical process, the 

larger part of the concentration being the result of loss of oxygen, 

which is in larger proportion at the outset. The oxygen loss is disproportionally great as compared to that of the hydrogen. The 

liquid putrefaction products of the algae must almost certainly 

have entered into the groundmass of the coal and participated in 

the infiltration of the immersed structural vestiges of higher and 

more enduring types of vegetation. The progressive deoxygenation 

of the organic matter effects a concentration of the bituminous compounds in the body of the organic material which is undergoing the 

processes of coal formation; that is, it accomplishes bituminization. 

However, the important point, so far as we are at present concerned, is the connection, as described by the distinguished French 

paleobotanists and later virtually corroborated by Potonie,a of these 

gelatinous (" sapropelic " of Potonie) elements with a highly bituminous 

quality of the fuel.

o Jahrb. K. preuss. Landesanstalt u. Bergakad., vol. 25,1907, pp. 342-368.
50 THE EFFECT OF OXYGEN IN COAL. 

CHARACTERISTICS OF ALGAL COALS.

We have next to note the following circumstances: (1) It will be ' 

seen on consulting the ultimate analyses published by the French paleobotanists that these algal (gelosic or sapropelic) coals are relatively 

high in hydrogen and low in oxygen, as is to be expected of coals that 

are tinged with the character of bitumen; (2) I have observed that 

those fuels, especially if Paleozoic and consequently more altered, 

are apt to fuse and even to swell on burning.

i

POSSIBLE CONNECTION WITH COKING QUALITY.

Now, these qualities, fusibility and swelling; concurrent with bituminization, which appear generally to characterize fuels known to 

contain recognizable quantities of gelatinous micro-algae, are also 

necessary to the coking quality in coals. It is permissible, therefore, 

to inquire whether the coking property may not be due, at least 

among coals relatively low in fixed carbon, to some unascertained but 

not improbable proportion of gelatinous algal (sapropelic) matter 

entering into the original ingredient mass from w'hich the coal was 

formed, and either directly or indirectly imparting-to it this fusibility 

and tendency to swell.

Micro-algal ingredients, sometimes forming layers of considerable 

thickness, are recognized in peats, and their presence, occasionally in 

great numbers, has already been noted in a number of remarkable 

brown coals which have not been altered so far as to preclude satisfactory microscopical examination. Yet the detection by means of 

the microscope of such minute and delicate organisms as the algae 

described from some of the bogheads and cannels, even if vestiges 

happened to be preserved, in coals so highly changed by the dynamochemical process as the coking coals, is a matter so difficult as perhaps 

to justify consideration as improbable. Being apparently barred at 

present from satisfactorily determining their presence by direct.mechanical means, we are therefore left to search the evidence of the 

chemical analyses.

Not only does it appear that among coals of the -same degree of 

progressive devolatilization those with the greatest amount of recognizable micro-algae show hydrogen and oxygen most nearly in the 

proportions shown in bitumen, but'in general it also seems, conversely, 

that those normally sedimented coals whose ultimate analyses approach most nearly to that of bitumen bear the more distinct microscopical evidence of the presence of the algae. The coals whose large 

volatile combustible matter contains relatively the highest hydrogen 

and the lowest oxygen, tims approaching nearest the bitumen analyses, are those in which the organic remains described as micro-algae 

are most predominant and often best preserved.
RELATION OF OXYGEN TO COKING. 51

Of the following analyses No. 1 re represents the Torbane Hill boghead; No. 2, a the Kerosene shale (Permian) of New South Wales; 

No. 3,6 a hard pitch; No. 4,b "pitch E," used in briquetting tests.

Analyses of algal coals approaching bitumen and of pitches.

No.

1

2

3

4

S.

0.88

.60

H.

8.50

9.03

4.50

4.22

C.

05.44

76.61

90.34

91.30

O+N.

3.44

2.87

3. 00

2.99

Ash.

22.62

10.64

1.10

.83

Moisture.

0.33

1.02

The tentative inference that sapropelic matter and the bituminous 

concentration 0 have a direct connection in these high-volatile coals 

is, I believe, quite justified.

'If the inference is correct that in the high volatile <3oals high bituminization (concentration of bituminous substance) and gelatinous 

algal (or sapropelic) ingredient elements go together, and if the observation of the connection between the presence of the latter (and consequent bituminization) with the tendency of the coal to fuse and 

swell is well founded, it seems probable that such coals of high bituminization will contain algal elements and (what is more important) 

fuse on burning in the mass. In other words, we may conclude that 

high volatile coals whose analyses show sufficiently high bituminization will coke by the ordinary process. The degree of bituminization 

in these coals is indicated by the relative excess of hydrogen as compared with the diminished oxygen in dry coal. p It is expressed by 

the ratio H:0.

HYDROGEN-OXYGEN RATIOS OF COKING COALS. 

DESCRIPTION OF DIAGRAM IN PLATE III.

The test of this working hypothesis lies in the examination of the 

H:0 ratios, dry-coal basis, of the coals with reference to the known 

behavior of the fuels in coking tests. The data essential to the study 

of the analyses for this purpose are set forth in diagram in Plate III. 

Sulphur is omitted from this diagram because it does not seem to 

influence the coking quality of the coal, though of course greatly 

affecting the quality of the coke from the metallurgic standpoint. 

Ash also is omitted as not essential to the comparison.

In this diagram all the coals are rearranged in the order of their 

fixed carbon percentages (F. C.) in pure coal, as given in Table 2, and

a Renault, B., Les micro-organ ism es des combustibles fossiles, p. 149.

bProf. Paper U. S. Geol. Survey No: 48, pp. 266, 267.

cThe gradual development of distinctness in the chemical resemblance to bitumen as progriissive 

(levolatilization eliminates more and more of the oxygen is essentially mere concentration. I therefore 

employ this term in place of enrichment, which suggests that bitumen has been brought in from some 

source entirely outside of the bed of coal.
52 THE EFFECT OF OXYGEN IN COAL.

with the same numbers. This order is chosen as conforming, to some 

extent, to the evolution of the coals. It is genetic in so far as it shows 

the progressive devolatilization of the coals that is, the progress in 

their dynamochemical alteration or improvement.

In order to present the additional essential criteria in a simple and 

graphic arrangement for comparison, the hydrogen-oxygen ratios are 

platted as heavy continuous lines extending to the right, and the 

ratios of volatile carbon to carbon (VC:C) are platted as heavy broken 

lines extending to the left, from a point representing nearly complete 

devolatilization. In the figure columns both these ratios are expressed as percentages. For comparison with the H:O ratios the 

available hydrogen has also been platted as light broken lines extending to the right.

The annotations as to coking, at the right, are mainly those based 

on the tests by the United States Geological Survey and kindly furnished by Mr. J. S. Burrows, chief inspector. Information from other 

sources has been incorporated regarding some coals not tested for 

coke by the Survey.

INDICATIONS OF RATIO LIMITS.

The evidence of the hydrogen-oxygen ratios as to the coking quality 

of the coals needs no extended discussion. A review of the wide 

fluctuations in the H:O ratios, together with the annotations as to 

coking, strongly indicates, so far as the tests have been made or the 

information is at hand, that, below the highest of the semibituminous 

coals which are approaching anthracitization, those coals with aH:O 

ratio (percentage) of 59 or more, with but one or two exceptions, 

make coke by the ordinary commercial process. Nearly all those 

below 59 and above 55, so far as tested, make a coke, and among those 

ranging down to a ratio of 50 a large percentage coke, while one or 

two of the tested coals coke at a slightly lower ratio. It would seem, 

however, that the cokes made from those coals with a H:0 ratio less 

than 55 are usually very poor and apt to be brittle and dark.

It appears, therefore, that among coals which are not too far 

devolatilized practically all that are sufficiently bituminized that is, 

have a H:0 ratio of 59 or over are almost certain to possess the coking fusibility, and that coke of good quality may usually be expected 

from coal with a ratio as low as 55, while very poor results may be 

obtained when the ratio is as low as 50. The best cokes obtained by 

the ordinary process are made from coals having a ratio of 60 or over.0 

In the H: 0 ratios of Table 2 and Plate III no oxygen compensation 

is made for sulphur in pyrite.

o The coking tests made by the United States Geological Survey are based on the ordinary beehive-oven 

process.
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE III A

No, 

4a

1

$

7

9a

3

147b

11

8

2

4

20

63

12a

9

51a

203

18

19

41

57a

2b

52a

56

26

5

25

ICO

61

14

13

51 

44a

17 

99 

105 

49

69 

55 

52 

66 

184. 

67 

83

81 

142 

80 

48

Lot.

Mont.3816

VI ass. 1

Fla.1

Tex.l

Wyo.3892

N.Dak.3

CaL3773

Cal.l

KDak.l

N. Dak. IB

Ark. 10

Wyo.2B

Iowa 3

Wyo.2326

Wyo.3

Batan

Mo.4

Wyo.2

Tex.2

Wya4

Wyo.3605

Wyo.3694

N.Mex.3952

Wyo.4B

I11.7A

N.Dak.2B

Wyo.l 

Ind.10

mi.

m.2

N.Dak.2 

Ihd.l

Wyo.3693

N.Mex.2 

III.9B 

Ohiol 

in TO

111.30 

I11.22A 

Iowa 4 

Ind.14 

Utahl 

Ind.13 

Wyo.6

I11.9A 

Ind.7 

Ind.6 

Iowa 2

Locality,

Halifax'

Orlando

Crokett

FaU River <*>

Wilton C

Stone Canyon

Tesla

Lehigh

Lehigh e

Lester

Cambria

Altoona

Uinta County

Aladdin

Philippine Is. ^

Barnett

Cambria

Hoyt

"Hanna

Hanna

Labarge Range ^

NearJBlackrock

Hanna

Collinsville

Williston

Monarch

O'Fallon

O'Fallon

Williston

Mildred 

Labarge Range "

Galliip 

Staunton 

Wellston

Shiloh station 

Maryville 

Carterville 

Seelyville 

Price 

Terre .Haute 

Kemmerer

Staunton 

Littles 

Hymera 

Hamilton

F. C. in 

pure coal.

r oo 77

P28.51

P29.95

L40.41

S41.22

L43.30

48:22

S46.47

L46.47

L47.81

L47.92

48.03

48.77

S49.33

.49.59

S49.71-

49.76

49.86

L50.43

S50.46

S50.54

S50.63

50.69

S50.82

50.89

L50.93

S51.03 -

C1 00

51.35.

51.38

L51.56

51.70 

SS2.06

S52.07 

52.29 

52.30 

52.31

52.48 

52.51 

52.52 

52.70 

52.77 

52.81 

S52.83

52.86 

52.86 

52.87 

53.00

H-f

1 ye

1.69

r.so

2.38

1.73

1.50

 f.37

2.78

1.83

1.44

1.68

.2.95

3.54

2:41

2.45

2.64.

4.49

2.93

2.06

2.52.

2.71

-.37

3.90

3.48

2.99

1.18'

2.47

4:05 

3.35

3.05

1.74

3.33 

2.50

2.96 

3.60 

3.60'

3.40-. 

3.12 

3.25, 

3.50 

4.02 

3.46 

3.06

3.65 

3.91 

3.71 

"3.45

Her o"*

23.1

21.5

20.9

29.9

25.2

25.7

55.4

34.9

26.1

25.2

22.6

.46.2

62.0

31.5

38.fi

28.0.

94.»

40.3

25.1

.29.2

31.3

11.1

56.8

37.9

50.0

26.4

 31.1 

61.6

53.0

53.7

23.3

29.0

43.6 

53.6 

60.4

49.1 

51.6 

S4.9 

56.1 

552.2. 

58.3 

33.9

53.7 

68.0 

71.8 

59.3

 ' "" ' ' """" ~ '~ ~ """ ~

....-.......:.:......'--:'..'.. "" ^

 

.............-......_.....__._._._ _

^

67.46 

54.09

52.52

44.29

42.03

41.1-5

39.21

"35.20

36.17

32.3?.

32.92

36.69

35.68

29:66

29.78

30.95:

38.G2

32.36

30.00

32.93

33.12

17.47

36. 1C

33.29

33.55

29.67

32.27 

34.75

33.73

32.96

28.40 

31.40

"28.85

33.29 

32.62 

32.75

OO 1C

31.02 

31.26 

32.70 

31.28 

34.93 

33.71 

30.56

31.79 

33.83 

33.49 

r30.85

Remarks.

No coking test

Distilled for oil

No coking test

Makes brittle coke

Burned to ash.

Cokes fairly well

No test

Makes coke

No test

Good hard coke on I11.7D

No test

Small pieces of coke in test

Poor hard and soft coke

Cokes fftirlv well

No test 

Good heavy coke 

Hard coke on I11.7D

No test 

No test 

Cokes 

No test 

Soft dense coke in test 

No test

No test 

Fair though brittle coke 

Good light-gray silvery coke 

Coked in small pieces.

No. 

4a

1

6

7

9a

3

147b

11

8

2

 4

20

63

12a

9

51a

203

18

19

41

57a

2b

52a

56

26

5

25 

153

61

14

13 

51

44a

17 

99 

105 

49

69 

55 

52 

66 

184 

67 

83

81 

142 

80 

48

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC 

The limits of the diagram include Q percentages over 10 and under 290, -~- percentages under 57, and available H over 2.7.
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE III B

No.

52b

120

33a

22

74

87

149

43

32

72

98

55a

inn

73c

38

168

113

31

C.Q

76 

107

10 

94 

42

90 

15

1QA

66a

2a 

45 

172

81a 

28 

24 

117 

62

102 

138 

HOa 

154

16 

91 

92

Q9

40 

57 

53a

12

Lot.

Wyo.2325

m.18

N.Mex.3811

Tex.4

Ind.2

Ind.16

Ind.7B

Mo.l

Colo.l

Ind.T.4

Ind.5

Wvo.3698 

Ofiio 9B

Wyo.2283

111.27

Ohio 10

Mo.6

Montl

til net)

111.14 

Ind.9B

Ind.T.5 

I11.23B

Til fl

Mo.5 

Mo.7A 

Ky.2

Colo.3498

Mont3701 

I11.23A 

Ohiol2A

Ark. 411 

Mo.7B 

Tex.3 

Ind.8 

111.15

Ind.9 

Kans.4 

.Wyo.3891 

Ohio 8

Mo.3 

Ind.12 

Ohio 2 

m.26

Ind.3 

I11.29B 

Wyo.3917

Mo.7C

Locality.

Almy

Lasalle

West of Putnam

Hoyt

Booneville

Lanton

Littles

Sprague

Lafayette

Lehigh

Hymera

Labarge Range o

Mammoth Hill

Auburn

Mineral City

Huntsville

Red Lodge

Springfield

Lehigh 

Donkville

Higbee 

Nbringer

Meeker

"Near Miles & 

Donkville 

Bellaire

Near St Michaels 

Noringer 

Olsen 

 Terre Haute 

Centralia

Macksville 

Atchison 

Mt McDougal 

Dixie

Mendota 

Hartwell 

Superior

Booneville 

Lavingston 

Fort Steele

Noringer

P. C. in 

pure coal.

S53.02

53.13

S53.25

L53.27

53.28

53.41

53.50

53.55

S53.69

53.74

53.75

S53.81

CO OO

S53.83

53.85

53.91

53.95

S53.96 

CQ oa

54.03 

54.03

54.07 

54.20 

54.20

54.21 

54.27 

54.28

54.45

S54.46. 

54.48 

54.55

54.58 

5459 

L54.68 

54.68 

5476

5476 

54.79 

54.79 '

KA O1

5493 

5497 

55.00 

55.14

55.16. 

55.24 

855.36

55.43

AH- H w8"

2.28

3.80

2.93

2.00

3.54

3.52

3.81

3.58

2.63

3.20

3.57

2.46

2.24

3.13

4.16

3.63

2.75'

3.60

3.73 

2.63 

3.54

3.60 

2.87

3.74 

2:65

.99 

3.18 

3.95

3.04 

3.11 

2.18 

3.77 

3.26

3.64 

4.05 

2.93

o. to

2.98 

3.53 

3.61

3.35 

3.32 

3.29 

2.02

2.64

£<*> O'*

28.5

56.0

35.5

25.2

63.0

57.1

60.8

79.4

32.7

48.8

60.8

28.6 

54.8

26.5

49.5

57.9

67.1

35.6 

52.4

54.8. 

56.5

48.5 

51.9 

54.1

62.5 

50.1 

59 7

31.4

19.2 

50.3 

67.4

36.1 

56.6 

27.1 

67.5 

50.9

59.1 

97.9 

35.0 

56.0

52.5 

57.0, 

60.5'

56.4 

 52.2 

24.2

44.3

 .-..---.-..... ...I...

 _ _ 

TTTrrrrrrTTrrrTTTrTTTrr-i -

.......... ...... ..._"'...._

.........

.................. - . _, -

f4

30.74

31.80

28.50

27.29

32.09

31.75

32.48

32.05

29.61

30.54

31.77

27.94

28.22

29.82

31.89

30.85

28.47 

'29 17

30.60

29.28 

29.45 

30.22

30.33 

29.79

01 CQ

28.41

30.95 

29.18 

32.20

.29.73 

29.17 

25.29 

31.87 

29.46

31.21 

28.02 

29.90

 31 Ql

28.61 

30.04 

30.24 

29.84

27.96 

28.53 

'23.80

27.58

Hemarks.

No test

<io test

Vo test: is coked

Cokes well

No test

No test

Makes good coke

Poor soft, dense coke

No test

No test

No coke on test of I11.25A

No test

Small pieces of coke from test 

Coked 

No test

Good coke of good weight 

No test

Coked: light gray 

Good coke

No test

No testNo test

Fair coke; light-gray silvery 

Cokes: hard but brittle

No tendency to coke on test 

Good coke, metallic ring 

Coke soft, poor on test

No coke from test 

No test 111. 29 poor coke

No test

No

52b.

120

33a

22

74

87

149

.43

32

72

98

55a 

104

73c

38

168

113

31 

53

76 

107

10 

94 

42

90 

15 

130

66a

2a 

45 

172

81a 

28 

24 

117 

62

102 

 138 

HOa 

154

16 

91 

92 

82

40 

57 

53a

12

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC 

'The limits of the diagram include Q percentages over 10 and under 290, -~- percentages under 57, and available H over 2.7.
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE III C

No.

50

75a

205

59

111

137

52c

73

Il2a 

175a

96

108

73a

39a

33

84a

46

167

31a 

128

146b

131

75b

129

132

77

178

' 64

144

171

160

28a

46a

187

39b

70 

133

36 

39

75

103

147a

173b

101

171a

166a

174a 

154a

Lot.

Wash. IB

Colo:3462

W.Va.2

III 29

Ky.3

Ind.T.3

Colo.3463

111.31

Wyo.3509 : C6lo.4225

I11.24a

Ky.4

Colo.3490

Wyo.3699

I11.29A

Colo.3703

Wash.l

Ohio 12B

Colo.3729 

Wash. 2

Colo.3586

Ohio 11

Colo.3704

Ky.7

Ind.lSA

Ohio 3

Ohio 4

N.Mex.l

Wyo.5

Ohio 9A

Ind.T.2

Coto.3856

Colo.4050

Ohio 6

Wyo.3780

111.21 

Ky.9A

Iowa 5 

111.4

Ind.17

Ind.l8B

'Colo.S943

Colo.3939

Ind.ll

Colo.3938

Colo.3587

Colo.4036 

Wyo 3480

Locality.

Renton

Lay a

Clarksburg

Livingston

Barnsley

Edwards

Lay

Worden

Fort Steele

New Baden

WheatcroftBook Cliffs field

Labarge Range 0

Livingston

Axial

Renton

Bellaire

Carbonera

Book Cliffs field .

Flushing .

Axial

Central City

Winslow

Shawnee

Crow Hollow

Gallup

Rock Springs

Clarion

Hartshorne

Thompsons

Near Glenwood Springs

Neffs

Northeast of Hanna &

Troy 

McHenry

 Chariton 

Troy

Bicknell

Winslow .

Rifle Creek

Newcastle

Bugger

Newcastle

Book Cliffs field

Sunlight

F. C, in 

pure coal.

S55.56

55.65

55.71

55.82

55.99

56.08

56.16

56.33

56.36 

56.41

56.42

56.46

56.50

S56.51

56.58

56.61

S56.66

56.86

56.87 

56.88

56.88

56.89

57.03

57.05

57.12

57.13

57.13

S57.16

57.19

57.20

57.24

57.27

57.35

57.38

S57.41

57.48 

57.49

57.65 

57.72

57.76

57.82

57.95

57.98

58.00

58.08-

58: 14

58.19

CO OO

*-§

3.06

2.98

4.13

3.16

3.69

3.54

2.70

3.35-

3.01 

4.17

3.42

3.48-

3.01

2.32

3.10

2.37

2.80

3.97

3.30

3.41

3.61

2.50

3.51

3.59

3.29

4.04

3.08

3.08

3.40

3.88

3.21

2.58

4.19

2.79

3.02 

3.81

3.78 

3.01

3.17

3.40-

3.40

3.47

3.25

3.28

4.00

3.42

M37.5

35.9

77.0

47.2

61.9

60.0

32.1

51.9'

37.3' 

58.5

53.6

68.8

38.8

27.4

49.0

28.4

36.6

67.3

43.7 

54.5

43.4

62.7

30.4

60.4

68.7

50.8

77,2

39.3

36.2

54.8

65.5-

46.1

31.7

77.5

31.7

.41.9 

60.0

57.7 

48.5

50.5

50.8

41.1

43.9

52.1

40.3

55.0

39.0 

41.6

L... - " 

.-""" -^ """ - - ' ----

-- 

----..._-.- ....... ._......__

..... -_.^_. r-,, , .. .,_ . , . -, , ,.__.,.,..

 ----.. .::__ :.. .. " 

..-_.. _. -'.._- ... ... -

iH

27.89

27.62

32.16

26.80

23.64

29.86

25.95

27.62

27.81

ort c/7

26.87

29.63

27.75

,23.37

.26.07

25.85

27.37

29.57

27.33 

30.64

27.87

28.60

25.56

28.82

30.11

28.86

30.37

27.10

26.49

29.39

31.05'

27.73

24.13

30.08.

20.49

27.16 

27.88

25.66 

28.30

26.53

28.52

26.03

27.78

28.79

27.03

27.96

25.82

QC If!

Remarks,

No test

No coke produced

Good coke, somewhat brittle

Poor, dense coke

Fairly good coke

Unsatisfactory test

No test

No coke from test

Good coke, metallic ring

Poor, dense coke

No test

Good coke

Said to be noncoking

Said to coke well

.Good coke

Once coked commercially

Burned tc ashes in test

Pine heavy coke

No coke from test

,Good out brittle coke

Coked well

Noncoking

Good coke; metallic ring

.No coke from test 

Fairly good coking

Partially coked in test 

No test

Poor dark-gray coke

No- test; said to coke

Noncoking

Coke; medium cells

No test

No.

50

75a

205

59

111

137

52c

73

12a

96

108

73a

39a

33

84a

46

167

31a 

128

146b

131

75b

129

132

77

178

64

144

171

160

28a

46a

187

39b

70 

133

36 

39

75

103

147a

173L

101

171ac

166a

174a

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC 

*The limits of the diagram include Q percentages over 10 and under 290, -g- percentages under 57, and available H over 2.7.
U. S. GEOLOGICAL SURVEY

BULLETIN 382 PLATE III D

KoJ rirr

126 [

 134a

I m^^ \

HH| Ol |

png:

17lb 

146a 

1 IQiaJ 

54' . 

} 179a 1 

68 

148 

160a 1 

-136 

 23 

78 

34 

188 

176a 

.44

ti25_

1 47 

I 207

| 100 

1 60 

58 

71 

.110 

93 

.217 

183 

. "86 

 79 

165 

1 161a

[219 1 

ML77

.164 

135 

115 

143 

157 

185 

l'284l

Lot.

W;Va.l5 . 

N.Mex.4A__ 

Colo. 3541 

Ind.T.l 

N.Mex.4B \ 

Mont. 2 

Tenn.7A 

Monit.3 

Colo.3552 

Colo.3585 | 

Colo.3946~1 

Colo 3550 "1 

I11.9C 

0010.4048^1 

Ind.4 

Ohio 7 

Colo. 3936 

Ind.15 

Mo. 10 

111.12 

Ind..20 

Ind.T.2C 

Colo. 7573 

111.6

Irid.T.2B 

I11.21B 

Tenn.2 

N.Mex.3C 

Iowa 1 

Ili:6B 

I11.22B 

111.10 

N.Mex.3B 

Va.4 

Ohio 5 

N.Mex.SA 

Kans.2 

I11.34A 

Wy 0.4323 

W.Va.l 

W.Va.25 

Tenn.SA 

Ky.9B 

Ind.T.8 

Kans.l 

Tenn.SB 

1 Term. 5 

1 W.Va.21~

Locality.

Clarksburg ____________ . 

Brilliant _________ ____ . 

Book Cliffs field ____ . 

Henryetta _________ 1 

Brilliant j 

Fromberg I 

Wilder __ |_ 

Bridger ______ 1 

Near Durango j 

Book ClifTs field j 

Rifle Creek _[ 

Book Cliffs field 

Staunton _______ 

Sunlight 

Star City 

Danford 

Newcastle 

Linton 

Bevier 

Bush

Brazil _______ 

Hartshorne __ 

Hesperus __ 

Coffeen ___

Hartshorne 

Troy 

Gatliff 

Van Houten 

Laddesdale 

Coffeen 

Maryville _______ 

West of Frankfort 

Van Houten 

Darby __ 

Rush Run 

Van Houten ____________ 

Yale 

Harrisburg 

Greys ________ 

Kingmont ____ 

Charleston 

 Clifty 

McHenry 

Railroad car __ 

Fleming ' _____ 

Clifty 

Petros 

1 Winifrede

F. C. in

pure coal. 

58.28 

58.32 

58.34 

58.35 

58.48 

S58.49 

58.50 

S58.53 

58.54 

58.62 [ 

58.75 

58.79 

58.83 

58.91 t 

58.99 

59.00 

.59.01 1 

59.03 

59.04 

59.10 | 

59.14 "j 

59.18 

59.19 

59.22

59.25 

59.33 

59.38 

59.39 

59.42 

59.42 

59.43 

1 59.55 ~ 59.59~ 

59.60 ~ 

59.79~ 

1 59.87 

| 59.91 

59.97 

1 59.98 60.00~ 

1 60.03

60.08 -1 

| 60.15

I __ 60.10 

1 60.17 

j 60.23 

I __ 60.28 

1 /,60.28

*7TT

*8 o]

4.31 T 

3.8S1 

3.08- 

3.72 I 

3.89 T 

2.68 t 

4.05 T 

2.70 

4.05 

3.83 

3.26 

3.53 

3.01 

3.53 

3.24J 

3.841 

3.39 

3.55 

2.84 

:5.35

3.20 

4.04 

3.77 

3.11

3.55 

2.98 

4.07 

3.63 

3.25 

3.18 

3.24 

i 3-47_ 

j_3.48_ 

3.9l7 

3.54^ 

3.76 

3.72 

3.64 

2.84 

1 4 .31 

t 3.65 

4.28 

3.63 

3.57 

1 3.87 

I 3.88 

4M6 

|4.2a

w T °/°\ 0 7 i

101.9 H 

63.lt 

39.3 p 

59.3 t 

JS5.2 j: 

J35.2^ 

~~83.2 [ 

34.4 \ 

62.9 f 

53.8 t 

38.2 t 

49.9 

48.3 

^42.0 

~52.0 

69.8 

" 4S.3J 

' 56.4J 

47.6 

55.0 

57.6 

73.8 

52.5 

44.7

67.6 

43.2 

68.7 

59.1 

T64.3 

50.1 

[ 51 .1 

52.1 

57.8 

63.9 

00.2 

63.9 

91.5 

1 54.5 

[ 32.0 

79.7 

52.4 

106.1 

57.2 

64.8 

90.2 

1 101.6 

j 90.4 

77.5

r - .. . - -

 

 

- 

< 

vc<* c'-

31.26 

29.44 

26.26 

28.34 

29.45 

24.50 

28.95 

24.34 

29.24 

27.45 

24.65- 

30.57 

24.33 

25.34- 

26.04 

27.49 

26.70 

27.29 

23.19 

25.46 

26.62 

28.75 

27.74 

21.50 

28.43

25.29 

29.53

24.74 

22.90 

28.86 

26.25 

27.97 

29.30 

27.27 

27.75

25.42

29.31 

27.06 

27.24 

24.67 

26.86 

26.69 

26.90 

27.19 

28.75

* 

Very good hard, heavy coke 

Coked well

No coke from test 

Good heavy coke 

No test 

Coked

Cokes 

No test

Noncoking 

No test

Coke with poor structure 

Good coke

No test 

No test 

No test 

No test 

Commercial coke 

Said to coke poorly 

No test

No coke from test 

Good coke

Makes brittle coke 

No test 

Poor dull-gray coke 

No test 

Good heavy coke 

Good coke 

Good but brittle coke from test 

Commercial coke

No test

Good coke 

Fair brittle coke 

Cokes well 

No test; said to coke well 

No test 

Imperfect test 

Makes good coke 

Good" heavy coke 

Good hard, heavy coke

No.

215 

126 

134a 

146 

118 

29 

158 

37 

211a 

171b 

146a 

lOla 

54 

179a 

68 

148 

160a 

136 

23 

78 

34 

188 

176a 

44

19^

47. 

207

60 

58 

71 

110 

93 

217 . 

183 

86

165

219 

177 

164 

.135 

115 

143 

157r 

185 

234

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS. 

 The limits of the diagram include g percentages over ,. and under ,90, % percentages under 57, and availablj over 2.7.
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE III E

No.

224

88

186

173a

119

171c

208a

104

155

156.

112

72a

215a

114 

229

122

116 

175 

209 

149a

199 

170 

218 

204

145

141

146c

62a

221 

220

233

208b

127 

169 

192

226 

85

214

136a

159

147

174

84

173

65

95

97

201

Lot.

Ky.6

Kans.6

Tenn.3

Wyo.3570

I11.11B

Colo.3932

'Wyo.4303

111.34 B

Pa.13

Tenn.l

ilU2B

Colo.3545

Wyo.4299

Ala. 2 

Ky.l

111.13

111. 12 C 

W.Va.22B 

W.Va.23A 

Colo.3546

W."Va.23B 

I11.11C 

Va.2B 

Ky.lB

111.11

N.Mex.5

Wyo.4302

Utah 4013

Va.1 

Pa. 10

Ky.5

Colo.4010

111. 12 D 

Pa.6 

WVa_22A

Pa. 5 

Ala.2B

Pa. 11

Cblo.3640

Ala.1

H1.19B

Tenn.4

I11.19E

Kans.5

Kans.2 B

111. 19 C

111.3

W.Va.16.

Locality.

Miller Creek

Jewett

Gatliff

.Oyster Ridge

Carterville

Newcastle

Willow Creek

Harrisburg

Creighton

Fork Ridge

Bush

Book Cliffs field a

Willow Creek

Carbon Hill 

Straight Creek

Beriton

Bush 

Hernshaw 

Monarch 

Book Cliffs field

Monarch 

Carterville 

Crab Orchard 

Straight Creek

Carterville

Blossburg

Willow Creek b

South of Sunnyside a

Crab Orchard"

.Big Black Mountain

Gulch

Bush 

East of Millsboro 

H cm shsw

Ellsworth 

Carbon Hill

Charleroi

Book Cliffs field

Horse Creek

Ziegler

Oliver Springs

Ziegler

West of Mineral

Yale

Ziegler

Marion

Monongah

F. C. in 

pure coal.

60.39

60.54

60.56

60.61

60.68

60.71

60.74

60.76

60.77

60.84

60.87

60.89

60.91

60.95

fif\ QC

61.02

61.02 

61.02 

61.18 

61.19

61.23 

61.30 

61.42 

61.43

61.48

61.49

61.60

61.62

61.70

/»1 171

61.91

61.97

62.22

62.26 

co or

62.31 

62.31

62.46

62.54

62.59

6264

62.69

62.74

62.92

63.15 .

63.26

 3.26

63.27

H H °

~8

4.00

3.57

4.08

3.31

3.57

3.52

3.46

3.33

4.15

3.80

3.33

2.96

4.20

3.43

4.26 

3.41

3.45 

4.01 

4.14 

3.48

4.01 

3.64 

4.04 

4.11

3.50.

3.84

2.69

2.20

4.04

3.83

3.98

3.31 

3.87

4.27 

3.13

4.14"

3.27

3.98

3.47

4.05

2.66

4.04

3.62

3.41

3.30

3.85

§*J

61.4

73.2

64.1

43.2

59.4

45.5

44.5

52.3

83.7

65.3

53.1

87.0

58.8

52.5 

72.6

52.7

55.2 

70.4 

76.2 

46.4

70.3 

54.1 

70.2 

78.6

57.0

72.5

35.6

26.6

66.4 

78.0

-. 61.5 ;

60.0,

49.6 

85.4 

64.3

81.8 

48.6

77.1

39.2

74.1

60.9

70.3

38.3

82.6

107.9

54.1

55.4,

71.9

 .-_-_-_...._-. ... 

--.-._. _ ::: '- '- - -T- - 

_-.._--....._ _ _., - _ -^ , ._ _.^ .

p.. .... 7T-~~-"""" '

u--~ __- ........ '

..- ....- . " 

 -_ _ -_ - , 

.,__..__... _......_...... __

 - - _ ' 

 ___ ______________ " - ...» r- .._.... , . .« ^_, ^ .._..,..

_. .- . ..,.. ....... M __ ^

 . _ _ .. ... " __ - ^,

... ' '

-____ _-_-._ -.--___- .. ^

^

27.95

25.32

26.75

25.45

25.00

24.99

25.13

23.84

27.17

26.14

24.70

21.63

26.68

25.27 

27.11

24.73

24.35 

27.45 

27.51 

23.86

27.03. 

24.67 

27.37 

27.34

24.60

27.30

22.84

17.99

26.52 

27.02

26.49

25'.63

22.19 

26.55

OC tfA

26.90 

23.33

26.24

20.80

25.56

24.99

26.09

22.08

23.54

22.71

23.09

22.50

25.14

Remarks.

t

Good but brittle coke

Cokes well

Good but brittle coke

No test

Coked well

No test; said to coke well

Good strong, hard, heavy coke

No test

No test

Coked imperfectly

Dull-gray coke

No test 

Good coking coal 

Good coking coal

Cokes well 

No test; strong coke on 111. 11 D 

Very good coke 

Coked commercially

No test

Good heavy coke

Good hard coke

Afalfpc OYW? (*fi\{f*

Good but very brittle coke

No test; said to coke

No test 

Makes fine coke

Fine coking coal 

Soft, dense, dull coke

Cokes well

Cokes well

No coke from test

Is coked

No coke from test

Said to coke

No test

No coke from test

Poor brittle coke

Good hard, heavy coke

No.

224

88

186

173a

119

ITla

208a

104

155

156

112

72a

2l5a

114 

oort

122 ,

116 

175 

209 

149a

199 

170 

218 

204

145

141

146c

62a

221

OOA

233

208b

127 

,169

1Q9

226 

85

214

136a

159

147

..174

84

173

^65

95

97

201

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC The limits of the diagram include Q percentages over 10 and under 290, -~- percentages under 57, and available H over 2.7.
U. S. GEOLOGICAL SURVEY BULLETIN 382 PLATE III F

No.

139

242a

216a

231

231a

124

135a 

227a

202 

180

210a

73b

134

166 

poo

197

106

191

44b

243

208c

A«7O

25a

150 

245 

89

194 

151 

176

189

200

196

232

.121

239

O1 £

21

208

225

27 

235 

210 

227 

249

193 

231b 

.248

Lot.

111.16

Ala. 3770

Ala. 3771

W.Va.18

Ala. 3744

.111.28 C

111. 19 D 

Ala. 3769

TV * V <* £*/

Pa. 19 

Ky.8

.Ala; 3745

Mont 4115

Ala.3

Ala.4'

Pa.4

111.12

Pa. 12

Mont 3515

Va.3

AK3499

W. Vo.o

Mont 3512

Term. 6 

W.Va.13 

Tenn.gB

Tenn.9C 

Tenn.9A 

Pa.17

Pa.22

W.Va.5,

Pa.21

W.Va.9

Ala.5

W.Va.14. 

W Va_4

Mexico_l,

W;Va.4B

.W.Va.17

Tenn.ll 

.Ala.6 . 

Va.6 

Pa.16 

"V7 Va.19

PA? 

Cblo.4047 

WVa.6

Locality.

Herrin

Sydenton

Acton Basin

Glen Alum

Fallston

Herrin'

Ziegler 

Acton Basin

Herminie 

Sturgis

Coalmont

Stocket district

Garnsey

Belle Ellen

Greensburg

Ziegler

Atcheson

Belt district

Coeburn

Lovick

Belt distric

Waldencia 

Loup Creek 

Coalmont

Coalmont . 

Coalmont 

White

Huff

CoaTton

Cbnnellsville .

Powellton

LeHigh

.Loup Creek 

Bretz

Bretz

Hear Bretz

Ozone 

Dolomite. 

.Richlands 

Hastings

LigonSer 

Coal Basin 

Rush Run

F. C. in 

pure coal.

63.29

63.58

63.59

63.61

63.69

63.76

63.80 

63.87

CQ QC63.98 

64.23

64.23'

64.39

64.41

6459 

a A nv

64.98

65.00

.65.58

65.74

65:77

65.79

£*{* QTT

65.91

66.20 

66:39 

66,53'

66.59 

66.78 

66.84:

67:23!

67.25!

67.66

68.00

68.02

68.28

£Q OQ

68.36

68.93

69.13

69.74 

70.95 

72.39 . 

75.21

*7C OQ

75.30 

76.24 

76.94

a.|

3.42

4.5!

4.09-

3.99

4.00

3.29

2.87 

3.9f

4.34 

3.95:

3.68-

3.84

2.75

3.42

4.14

4.11

3.0T

3.84

2.88

4.30

3.99'

4.15 

2.2T s'.ss4.41 

3.92

3.92- 

3.80 

4.11

3.97.

4.01'

3.69

4.24'

3.60

4.13

3.18i

3.81'

3.85

3.35 

4.10 

3.76 

' 3-79

4.14 

4.05 

4.08 

4.17

Ho/ o-^

- 54.9

93.7

72.5

76.a

58.6

52.2

42.2 

65.4 

100.6

70.1 

61.9

61.8

41.8

60,7

93.9'

QQ d

95.7

48.4

74.2

51.1

%.! 

77.5

Q"> Q

32.9 81.0' 

103.J, 

89.6

77.8 

80,6 

97.5

82.9

83.6

68>4-

89.6

8U

78.1

QA ^

69.7

97.5

99.6

101.1 

91.6 

89.7 

87.5

152.0 

116.9 

126.5

r

. .::."_ .I'- 1, i"11

, ..-... ..-.. . -.-. ..__. 

 ._. --._ .._.: . 

 .-.-. .- .- ..- _

.-___- -_-. fc . 

 , _ 

' ~" mu -' ^ ~" 

.. . ...._-.. - ! _ -

.._ ..----_._.-. ... ....._...

. ... 

 ____ ._ ______ _-__."^"'_" 

; _ _ _ ___ 

.-_. ._ ._.._.._.._._..___.:. ' ""

_ ..-._ _____....._ _ ......

.-... ............_...

- ___._ ___.___.___- .________

..__.; _ _-_...- _ '- '

._.. j ....... _ ._ ._ - r 

 - - - T

^1c. 7 *

22.94

26.52

25.32

25.88

23.67-

22.19

21.77. 

 24.37

2

= 7Q

24.13 

23.35

23.63

19.16

23.62

24.56

OE TO

24,42

21.13

21.69

. 17.71

24.31

22,46

oq "i

15.09

22.80 

23.83 

21.95

22.40 

21.74 

21.83

21.30

21.46

20.30

21.02

19.96

20.02

OA CQ

19.12

20.65

20.61

18.97 

18.41 

16.11 

12.94

15.14 

.13.69 

'.13.41 

i!3.26

Remarks.

No test

Cokes well

Cokes well

Good hard, heavy coke

.Coking coal

Dark-gray coke; small cell structure

Good coking coal

Good heavy coke 

Fairly good coke; large cells

Said to coke well

Strong, hard, heavy coke

Fine strong coke

Makes excellent coke

No coke from test

Very good coke

Good heavy commercial coke

Said to make good coke

Good strong, heavy coke 

Very good coke; commercial 

Commercially coked"

Makes a good coke 

Good coke 

Good heavy coke

Good coking coal

Makes good coke; high ash

Excellent standard coke

Coked commercially

Good, heavy, silvery coke; metallia

Good, hard, commercial coke

No test

.Very good coke

Very good coke

Poor coke from test 

Heavy, light-gray silvery coke 

Dense coke from test 

No test Said to coke

uOOd COKlTl£f CO<u

.Good heavy coke 

Makes good coke 

Tough, dense coke; commercial

No.

139

242a

216a

231

231a

124

135a 

227a 

222

202 

18Q

.210a

73b

134

166

' OOQ

197

106

191

44b

243

208c

25a

150 

245 

89

194 

151 

176

189

.200

196

232

121

239

O1 £

21

208

225

27 

235 

210 

227

£?±y

193 

231b 

248

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC * The limits of the diagram include Q percentages over 10 and under 290, -~- percentages under 57, and available H over 2.7.
U. S. GEOLOGICAL. SURVEY BULLETIN 382 PLATE III G

No. 

195

.240

35

230

182.

123

237

212

250

206

181 

247

246

161

91 Q

190

244

241

228

236

^OOj

30

239a 

239b

242 

211

1£9

140

163

152.

Lot.

Ark. 3

W.Va.7

Ark. 9

Pa.l5B

Ark.l

Ark. IB

Pa, 15

Pa.&

W.Va.10

Ark.7A

Ark. 12 

W Va 19

W.Va.l2A

Ga.l

Md.l

Pa.8

Md.2

Pa. 20

Ark. 2

W.Va.24

Ark. 3174' 

Pa. L

Ind.T.9 

Ark. 5

Va.5B 

Va.5A

ArK.O

Pa, 3

R.I.1

Locality.

Sun

Bonanza

Wehrum

Huntington

Huntington

Wehrum

Kimmelton

Mora

Midland.

Big Sandy

Menlo 

Zenith

Georges Creek

Ehrenfield

Frostburg

Seward

Bonanza

Lloydell 

Gary

Paris 

Johnstown

Panama district 

Coal Hill

Blacksburg

Scranton

"Providence

F. C. in 

pure coal. 

77.40

78.18

78.97

79.23

79.25

79.66

79.77

79.91

80.15

80.36

80.45 

80.47

80.47

SO. 57

Qfi 7Q

80.94

81.28

81.36

 81.41

81.92

GO 07

82.87

83.34 

83.89

84.29 

85.18

86.89'

87.01 

91.09

93.73

"'I

3.46

3.65

2.88

4.02

3.41

3.36

4.20

3.55

4.18

3.50

3.26

3.98

3.39

3.42

3.94

4.11

4.28

3.73

2.83

3.61 

3.67

4.07 

3.35

3.49 

3.10

3.01 

2:30

.31

H °d or7 *

94.8

82.8

73.7

215.2

105.8

115.3

288.8

125.5

169.6

101.0

118.5 

295.7

173.0

79.9 

128.4

132.6

149.8

161.1

250.0

159.5

93.2

250.0 

164.0

253.2 

162.1 

151.4

104.4 

122.7

115.7

244.3

...... ^~

............................. ...... .

....................

........................._

................. . ......................

 , -

- -

......................................... ' "-

__ 

 ^-^ -. 

..................... 

V,N

11.41

10.68

7.71

9.07

10.00

9.40

9.11

9.42

11.63

7.64

9.15 

10.58

11.06

6.73 

10.55

9.02

9.49

10.39

.7.74

7.96 

7 49

6.02.

6.65 

5.82

6.58 

.4.65

3.20

9 Q**

1.18

1.98

Remarks.

Good quality coke

No coke from test

Cokes in by-product ovens

Soft, dense coke; poor cells

Burned in test.

Soft dense coke in test; coked in by.product ovens

Pieces of coke in charge on test

Good hard, heavy coke

No test Test of Ark.TB produced no coke

No test

Good coke

Poor dense coke from test

Poor soft coke

Soft dense coke from test

No test. Poor coke once shipped

Soft dense coke from test

No tendency to coke on test; burned to ashes 

No test

No test; said to be coked '

No test

No test 

No test 

No test

No test 

No test

No test

Not a fuel

No.

195 

240

35

230

182

123

237

212

250

206

181 

247

246

161

91 Q

190

244

241

228

236

OQQ

30

239a 

239b

242 

211 

162

140 

179

163

152

DIAGRAM SHOWING HYDROGEN-OXYGEN RATIOS OF COALS.

H VC *The limits of the diagram include Q percentages over 10 and under 290, -g- percentages under 57, and available H over 2.7.
RELATION OF OXYGEN TO COKING. 53 

APPLICATION TO ALGAL HYPOTHESIS.

Applying these observations to our tentative hypothesis to account 

coincidently for both bituminization and fusibility, the conclusion 

that gelosic (or sapropelic) elements have entered into the composition of certain of the coals in the list seems justified. So far as the 

coals low in fixed carbon are concerned, I am disposed to regard it as 

essentially confirmed.

The Barnett, Mo., coal (No. 203) with a fixed carbon (pure coal) 

percentage of 49.76 and a H:O ratio of 94.9 I regard as most probably 

gelosic (sapropelic). So also with the coal from Sprague, Mo. (No. 

43), with 53.55 fixed carbon and 79.4 H:O ratio, and Atchison, Kans. 

(No. 138), with 54.79 fixed carbon and 97.9 H:0 ratio. I have not 

personally examined specimens from any of the above-mentioned 

coals. Provisionally, I am inclined to believe that small portions of 

gelosic matter probably entered into others of the coals whose ratio 

percentage is conspicuously above that of the associated bituminous 

coals having nearly the same percentage of fixed carbon, though lower 

than those mentioned. Among the most prominent of these mention 

may be made of Stone Canyon, Cal. (No. 147b), with 46.22 fixed carbon; Altoona, Iowa (No. 63), with 48.77; Plymera, Ind. (No. 80), 

with 52.87; Clarksburg, W. Va. (Nos. 205 and 215), with 55.71 and 

58.28, respectively; Wilder, Tenn. (No. 158), with 58.50; Yale, Kans. 

(No. 79), with 59.91, and Clifty, Tenn. (No. 164), with 60.08. If an 

unknown, probably very small, amount of gelatinous algal matter 

entered into the composition of these coals, it probably has been optically obliterated, if not quite macerated. In passing it may be remarked that the provisional hypothesis appears to harmonize in all 

respects with the tendency of the coking coals to cohere when reduced 

to a fine powder under the pestle, discovered by Max Pishel a since 

the preparation of these tables.

COKING OF HIGH FIXED CARBON COALS. 

VOLATILE-CARBON RATIOS.

The reader will have noted in passing down the H:O ratio columns 

in Plate III that after reaching a fixed carbon in pure coal of 66 or 67 

per cent, H:O ratios of 60 per cent or over characterize all the coals. 

Accordingly it should follow that all these coals possess the fusing 

quality and are susceptible of coking. This is practically true, for it 

appears that nearly all the coals in this portion bf the list will coke up 

to a fixed carbon of about 79 per cent, beyond which, as may be noted 

in the "remarks," some of the coals do not coke well by the ordinary

o Econ. Geology, vol. 3, No. 4,1908, p. 265.
54 THE EFFECT OF OXYGEN IN COAL.

process, while others apparently refuse to coke. A typical example of 

the latter kind is No. 35 from Bonanza, Ark., with 78.97 fixed carbon 

and a ratio of 73.7. Inspection of the columns of VC:C ratios shows 

that the high fixed carbon coals which apparently are noncoking are 

relatively low in volatile carbon, while certain other coals with a fixed 

carbon as high as 80 are said to coke well, although sometimes with 

considerable waste of uncemented carbon. The volatile of these high 

fixed carbon coking coals, it will be observed, seems to be characterized by a relatively high proportion of carbon. According to the 

tests, and so far as the present series of analyses illustrates, it would 

seem that coals of over 79 per cent of fixed carbon in pure coal can not 

be depended upon for coking by the ordinary process if the volatile 

carbon to carbon ratio (VC:C) is less than 10 per cent. Several of 

these highest-grade semibitiiminous coals, which are approaching the 

semi anthracite group and whose volatile carbon ratio is less than 10, 

are said to give good results in "by-product ovens. An example is No. 

237 from Wehrum, Pa., in which the fixed carbon is 79.77 per cent 

and the VC:C ratio 9.11 per cent.

CONSULTATION OF EFFICIENCY ERRORS.

Another method of distinguishing the coking from the noncoking 

coals in this group with over 78 or 79 per cent of fixed carbon, more 

practical and perhaps more reliable than observation of the volatile 

carbon ratios, is consultation of the efficiency errors, for the examples before us seem to indicate that the highly developed coals which 

do not possess the coking quality show very marked deficiency errors. 

This is well illustrated by the analyses of the higher semibituminous 

and the semianthracite fuels from Arkansas.

HYDROGEN AND OXYGEN LOSSES IN THE PROGRESSIVE DEVELOPMENT OF COAL. .

An explanation of the general upward progress of the hydrogenoxygen ratios in coals of over 66 per cent fixed carbon (all such in 

the tables being high) may be found in the more unequal rate of loss 

in the hydrogen and the oxygen during the more advanced stages of 

the progressive devolatilization of the coals. Observation of the 

relative loss of hydrogen and oxygen in the different groups of coals 

(dry-coal basis) shows that the curve of the hydrogen, though 

inclined steeply at first in passing from cellulose and lignose through 

the peats into the lignites, grades very gently through the great body 

of subbituminous, bituminous, and lower semibituminous coals, but 

pitches more rapidly near the semianthracite rank. The oxygen 

curve, on the contrary, exhibits a much steeper gradient, dropping
RELATION OP OXYGEN TO COKING. 55

through a much wider range, while passing through the subbituminous and bituminous coals; but before reaching the semibituminous 

coals it begins to decline more rapid!}7 than the hydrogen curve, and 

this acceleration continues, soj that in many coals the oxygen percentage, as will have been noted, becomes considerably less than 

the hydrogen. Examples are Nos. 179, 190, 193, 211, 212, 213, 228, 

230, 231b, 236, 237, 239a, and 239b. This relatively accelerated 

loss of oxygen as compared with that of hydrogen is expressed in 

the increase of the ratios.

AVAILABLE HYDROGEN AS INDEX OF COKING COALS.

I have been very greatly interested since the completion of the 

first draft of this table in December to learn from ni}r chemical 

colleagues of the well-known hypothesis of the dependence of the 

coking principle upon the relative amount of available hydrogen. 

This method of determining from the ultimate analyses whether coals 

will coke, which has been discussed by Percy, is said to apply successfully in certain areas and groups of coals, though in other groups 

and regions it is regarded as a failure.0 On account of the unusually 

wide range in age, kinds, and characters of the coals represented in 

the accompanying -tables, it has been very interesting to compare 

the available hydrogen with the observations as to the coking quality. In the column to the right in Table 2 will be found the available hydrogen of all the coals. The same data are transferred, 

with their corresponding numbers, to Plate III, in which they are 

platted as light broken lines. Examination of the hydrogen percentages in this table shows that while they tend to parallel the 

H:O ratios there are many variances, because in general high total 

hydrogen means high available hydrogen, but not necessarily a high 

ratio with oxygen.

The diagram shows that while practically all the coals with an 

available hydrogen of 3.80 or more will coke well unless they are 

too high in fixed carbon, some good cokes result from fuels with less 

than 3.50. Several of the tests show cokes from coals with as low 

as 3.20 availableTiydrogen. Note the following examples:

Coking coals with low available hydrogen.

No.

10

14

26

Fixed 

carbon.

54.07

51.38

50.89

Available 

hydrogen.

2.63

3.05

2.99

No.

85

124

Fixed 

carbon .

62. 31

63.76

Available 

hydrogen.

3.13'

3.29

<» For discussion of the relation of the available hydrogen to the coking quality, see Fulton, John, Coke: 

a treatise on the manufacture of coke and other prepared fuels, and the saving of by-products; Scranton, 

1905, pp. 31-38.
56 THE EFFECT OF OXYGEN IN COAL.

Other coals with much higher available hydrogen fail in the tests, 

as shown in the following examples:

Noncoking coals with high available hydrogen.

No.

31a

40

96

Fixed 

carbon.

56.87

55.16

56.42

Available 

hydrogen.

3.30

3.32

3.42

No.

147a

236

Fixed 

carbon.

57.95- . 81.92

Available 

hydrogen.

3.40

3.73

This method also breaks down in the highest semibituminous 

coals. . The loss in volatile in most of the coals of that category 

leads to a falling off in the available hydrogen. However, on 

account of the relatively more rapid oxygen loss in the higher coals 

the available hydrogen percentages sometimes persist after the coal 

refuses to coke, as in the Bonanza, Ark., coal (No. 236).

It may have been its failure as a coking index for the coals which 

are approaching semianthracitization at the Allegheny Front, in 

Cambria County, Pa., that led Fulton a to regard this method as of 

doubtful reliability.

HYDROGEN-OXYGEN RATIO THE BEST INDEX.

On the whole it is fairly evident that in coals of less than 79 per 

cent fixed carbon (in pure coal) the H:0 ratios, dry-coal basis, offer 

surprisingly reliable, narrowly defined, and logical criteria for determining the presence of the coking quality from the ultimate analysis. 

It has also been noted that in the succeeding and higher coals coking 

is generally possible if the amount of carbon in the volatile is relatively large; also that most of the coals whose H: O ratio is high but 

which refuse to coke are clearly distinguished by their marked

calorific deficiency with reference to the C: (O + ash) ratio and 

efficiency curve.

STATUS OF ALGAL HYPOTHESIS.

Since practically all coals in the table having fixed carbon contents of 66 per cent or over are* found to show high H: 0 ratios, and 

possess the coking capacity thereby indicated, the provisional algaelement hypothesis can not be regarded as demonstrated by the 

ultimate chemical analysis; that is, it does not seem tenable to 

conclude that all of these coals fuse by reason of the presence of an 

alga-element. Yet the tentative hypothesis appears to have such 

strong support in coals of higher volatile that it commands respecto Fulton, John, Coke and.coke making. Ed. 1905, p. 31.
RELATION OF OXYGEN TO COKING. 57

ful consideration. It appears that in the course of the concentrations incident to progressive devolatilization, more rapid loss of 

oxygen brings about in the higher coals the same approach to bituminization (high H:0 ratios) that in the lower coals resulted from the 

nature of the ingredient matter. That sapropelic influences, even in 

the higher coals, bear directly on the best coking results is not precluded from possibility. The conspicuous tendency of the recognized alga coals to preserve not only a high hydrogen but also a very 

high percentage of volatile carbon, may perhaps account for the 

persistence of relatively high carbon in the volatile, and for the 

apparently concomitant tendency to fuse, in some of the semibituminous coals which have fixed-carbon contents of 80 per cent 

or more. Examples of such high-volatile carbon coals are the 

following:

Coals high infixed carbon, showing also high volatile carbon ratios.

No.

241

213

Location.

Zenith, W.Va. ........

Fixed 

carbon.

81.36

80.73

VC:C 

ratio.

10.39

10.55

No.

246

250

Location.

Big Sandy, W.Va.....

Mora, W. Va..........

Fixed 

carbon.

80.46

80.15

VC:C 

ratio.

11.06

11.63

MIXTURE OF COALS FOR COKING.

The data given in Plate III are rich in suggestions as to blending 

of coals in order to obtain either the best coking results,0 or successful 

treatment of coals that refuse to coke well by the ordinary process. 

These suggestions relate not only to the mixing, according to the 

practicabilities of the regional trade conditions, of coals with relatively 

high H:0 ratios and moderate fixed carbon,like that at Blossburg,N. 

Mex., 6 with others whose ratios are hardly up to the standard for good 

fusion; but also to the mingling of certain coals high in fixed carbon 

with others rich in volatile matter that is, high in hydrogen and 

carbon. For example, the high H: 0 ratios of the rich-volatile coals 

listed below promise mutually beneficial economies if finely ground 

and mixed with such coals high in fixed carbon as those in the second 

part of the table, more especially since in some of the latter there appears to be waste 'df fixed carbon when coked by the ordinary process.

" The sulphur and ash-which so thoroughly control the market value of the coke are not. considered in 

this discussion.' For percentages of these, see Tables 1 and 2.

*> See No. 141 (F. C. 61.49, H: O ratio 72.5); also Brilliant and Van Houten: No. 126 (F. C. 58.32); No. 118 

(F. C. 58.48); No. 100 (F. C. 59.39), and No. 86(F. C. 59.87). Itwould be interesting to note trials of coals 

such as No. 138, from Atchison, Kans. (F. C. 54.79), or Sprague, Mo.,. No., 43 (F. C. 53.55), or Hartshorne, 

Ind. Ter., No. 125 (F. C. 59.25) when comminuted and mixed for the ovens with some coals with lower ratios 

from the Rocky Mountain coal fields; though the sulphur and ash of Nos. 138 and 43 are too high for tolerance in commercial coke.
58 THE EFFECT OF OXYGEN, IN COAL.

Comparison of two classes of coals suggested for mixing.

COALS RICH IN VOLATILE MATTER, WITH HIGH H: 0 RATIOS.

No.

155

-164

167

169

m

Locality.

Creighton, W. Va......

Bellaire, Ohio..........

East Millsboro, Pa.....

Bellaire, Ohio. .........

Fixed 

carbon.

Per cent. 

60.77

60.08

56.86

62.26

54.55

H:0

ratio.

Per cent. 

83.7

106.1

67.3

85.4

67.4

No.

193

90^

215

222

Locality.

fMarlrQVmrCf TW Va

Fixed, 

carbon.

Per cent. 

75.30

55.71

58.28

63.88

' ' H:O 

ratio.

' Per cent. 

152. 0

77.0

101.9

100. 6

COALS HIGH IN FIXED CARBON.

30

161

212

213

Gary, W. Va...........

Zenith, W. Va.........

82.87

80.57

79.91

80.73

93.0

79.9

125. 5

128.4

228

230

244 Ehrenf eld, Pa .........

81.41

79.23

81.28

250.0

215.2

149. 8

It is possible that some of the coals last mentioned or some of those 

farther north in Pennsylvania might mix to advantage with some of 

the high-volatile and high-ratio coals of Michigan, the Lower Verne 

coal for instance.

GENERAL OBSERVATIONS ON THE TABULATED COALS.

RANGE OF THE SAMPLES.

A general view erf Plate III shows the wide range of the coals which 

have been investigated by the United States Geological Survey. The 

ultimate analyses, standardized under the direction of N. W. Lord, 

include most of the commercial coals and extensive coal areas of the 

country.

RANK OF PEATS AND LIGNITES.

It is interesting to note that although the peats (Nos. 1 and 6, 

marked P), not having been subjected to the action of dynamochemical agencies, naturaUy gravitate to the foot of the scale of fixed carbon percentages, they are preceded in the scale by the Fort Union 

(Eocene) brown lignite from Glendive, which consists largely of a 

compressed accumulation of logs and sticks. The low fixed carbon 

of this coal is probably due to the lack of maceration or putrefaction 

previous to the development of antiseptic conditions. With the development of asepticity in a coal-forming mass, no further obliteration of the vegetal structures occurs except such as result from infiltration and compression (deformation). In the normal course of 

events the dynamochemical influences follow.

Following the peats are mingled brown coals (denoted by L) and 

subbituminous coals (S) more familiarly known as "black lignites." 

Interspersed among both of these types occur some of the lower grade.
GENERAL OBSERVATIONS. 59

bituminous coals as recently classified by M. R. Campbell by their 

color and characteristics of weathering. Among the latter are several 

which, as we have already noted, appear to be somewhat gelosic 

(sapropelic), a relatively low fixed carbon being characteristic of that 

type of coal.

EXPLANATION OF HIGH OXYGEN.

Remembering that the hydrogen-oxygen ratios are based on moisture-free coal, the persistence of a relatively high oxygen content and 

consequently low ratio, even in certain of the coals of moderate 

fixed carbon, is striking. Excluding the coals that have taken up 

oxygen as a result of exposure or weathering,0 the high oxygen of 

the low-ratio coals remaining in any group characterized by a 

definite fixed carbon may be explained either by (1) abundant natural charcoal, which has given the sample an abnormally high 

fixed carbon, or (2) differences in the original ingredients and conditions of deposition which have given the coal a chemical aspect 

approaching that of humic or ulmic acid, in contrast to the coals 

whose high H:O ratios give them a bituminous aspect.

QUANTITATIVE RELATION OF VOLATILE CARBON AND HYDROGEN.

One of the most significant features indicated graphically in. Plate 

III is the relations suggested by the two sorts of'volatile ratios. 

The rapid increase in fixed carbon in the peats and lignites at the 

beginning of the column is of course accompanied by a decrease in the 

volatile carbon, as expressed by the VC:C ratios. This decrease is, 

nearly parallel to the decrease in volatile combustible matter which 

is the difference between the fixed carbon and "pure coal." But 

even before the lignites are passed over it is evident that to a certain 

extent a coordinate relation exists between the volatile carbon and 

the hydrogen. The coals whose hydrogen is relatively high as compared to the oxygen are seen almost invariably to have a high volatile carbon; so that the lines representing the two ratios tend conspicuously to approach or withdraw from each other throughout the 

greater part of the diagram. The Barnett (Mo.) coal (F. C. 4Q.76) 

shows this especially well, and evidently has a very large proportion 

of both hydrogen and carbon in the volatile. Presumably these two 

elements are largely in chemical union at the moment of escape. 

On the other hand the distant retreat of the ratios in the weathered 

coal from the Labarge Range (F. C. 50.63) shows most convincingly 

a great amount of highly anticalorific oxygen, evidently the overwhelming component in the volatile combustible matter.

a Coals with a, 6, and d affixed to their locality, in PI. Ill, are examples more or less affected by exposure.
60 THE EFFECT OF OXYGEN IIST COAL. 

LOSS OF VOLATILE MATTER.

Some points relating to the devolatilization of the coals deserve 

special notice. The relative decrease of the volatile-carbon ratios as 

compared to the increase in the fixed carbon column seems to be rapid 

in passing from 40 to 50 per cent fixed carbon. Above this the relative 

loss of volatile carbon is slight up to near 63, but still higher the loss 

appears slightly to accelerate; and in the coals having 70 per cent or 

more of fixed carbon the ratios seem to fall of! a little more rapidly. 

The unusually low volatile-carbon ratios of the noncoking high semibituminous coals is well seen in the retreat of the VC: C lines for 

these coals in Plate III.

The falling off of carbon in the volatile of the higher coals is accompanied by a general decrease in the oxygen as compared to the hydrogen. The higher H:0 ratios show that the volatiles are becoming 

richer in hydrogen and lower in oxygen in passing to the semianthracite group. At the same time, however, the amounts of available 

hydrogen fluctuate in marked reactions, though tending to hold 

their own fairly well from 65 to 75 per cent fixed carbon. Above 

this they react wildly, and on approaching the anthracites they decline rapidly, regardless of the H:0 ratios. Yet, as I remarked in 

the discussion of the curve variance, the loss in calorific efficiency in 

the latter coals seems to. me disproportionately large as compared to 

the loss of available hydrogen.

RELATION OF STAGE OF COAL FORMATION TO CLASSIFICATION.

LIKE ANALYSES FOR COALS OF DIFFERENT ORIGIN.

In passing down the columns of Plate III the reader will doubtless 

have noted that the middle-grade bituminous coals of the Cretaceous 

and Tertiary mingle with the lower-grade coals from the Eastern Interior basin, and are like them as to fixed carbon contents, H:0 ratios, 

and relative volatile carbon. So it is also in the higher bituminous 

coals. There are in general no appreciable differences to be noted 

in the ultimate chemical analyses. In illustration of this fact, attention may be called to the agreement in fixed carbon, hydrogenoxygen ratios, and volatile-carbon ratios, as well as in the actual 

percentages of composition, between such coals as those, from the 

-. Raton-Trinidad district 0 of upper Cretaceous age, and the high-grade 

eastern, Paleozoic coals with which they are associated in the table; 

or, to cite a specific illustration, between Van Houten, N. Mex. 

(No. 86, F. C. 59.87) and Rush Run, Ohio (No. 183, F. C. 59,79), or

a. Allowing for low sulphur in the western coals here mentioned. See No. 141 (F. C. 61.49), No. 199 (F. C. 

61.23), and No. 100 (F. C. 59.39).
CLASSIFICATION. 61

Darby, Va. (No. 217, F. C. 59.60). In the lower grades of bituminous coals the Cretaceous and Tertiary samples apparently have 

slightly higher volatile-carbon ratios as compared with the H:0 ratios 

than the Paleozoic coals of the same rank. This may be due to the 

amount of resin in most of the former. Under advanced devolatilizing influences the resin appears to be transformed, possibly to disappear in the volatile. 0

DISTINCT CATEGORIES IMPOSSIBLE.

Plate III in connection with Table 2 conclusively shows the futility 

of lookin'g in the ultimate analyses for characters by means of which 

coals may be grouped into distinct and natural categories. Such a 

classification is an impossibility with only the current data. There 

are no distinct lines of separation of coals into any categories. From 

the very circumstances of coal formation the constantly varying 

ingredients, conditions of accumulation and deposition, and relations 

and intensities of the processes it is evident a priori that between 

each type and any other type there must be, since coal is merely a 

mixture of chemical compounds, every degree of intergradation. 

The classification of coals on the basis of their chemical analysis 

must therefore be absolutely arbitrary, with very finely drawn as well 

as purely empirical distinctions.

COMPARISON OF TYPES.

The discrimination between lignites and subbituminous coals presented in Table 1, which agrees with Campbell's classification (see p. 

10), has the great merits of simplicity and naturalness of grouping, 

readiness of application, and practical freedom from technical criteria. It is the only kind of classification that is adapted to common usage. Yet the difficulties due to the transitions from group to 

group are not less real and perplexing. Neither is it strange that, 

being based on physical characters and weathering criteria, it does 

not conform wholly to the conditions indicated by the analyses.

The fixed carbon column of Plate III shows conspicuously a somewhat indiscriminate mingling of lignites (L), subbituminous coals 

(S), and low-grade bituminous coals. In the ratio columns the intermingling of lignites and subbituminous and bituminous coals appears 

to be limited to border zones, the more important transgressions being 

those caused by weathering of the coals. 6 So far as present analyses 

are competent to serve as a basis for calculations it seems that in 

most coals the H:O ratio may provisionally be regarded as ranging 

up to 22 in the peats; from 22 to 29 in the lignites (brown coals);

a Additional field observations are needed on this point. *> No. 21) (F. C. 50.53) is weathered.
62 THE EFFECT OF OXYGEN IN COAL.

from 28 to 38 in subbituminous coals; and from 31 upward in the 

younger low-grade bituminous coals, or from 40 upward in the 

Paleozoic coals. The ratios, as may be noted in Plate III, do not all 

fall within these limits; but it is believed that additional data (which 

are much needed) will show that they fall generally within the limits 

here provisionally outlined. The lowest ratio for a Paleozoic coal in 

the table is 38.3 for a Zeigler analysis (F. C. 62.74). Mr. Campbell's 

classification is thus seen greatly to lower the under limit of the bituminous category, so as to include therein a large number of coals 

which are much less advanced in the coal-forming process than the 

lowest grade of the American Paleozoic coals.

It is well known that the coals of certain districts exhibit characteristics peculiar to the district or perhaps to their kind. For example, the xyloid lignites of North Dakota are in general marked by 

low H:O ratios; the Kootenai coals of the Great Falls field have 

comparatively low hydrogen and carbon in their volatile, and consequently low H:0 ratios, though, on account of the great amount of 

charcoal, their fixed carbon is as high as that of many of the fine coking 

coals of the Appalachian trough; 01 but it is also true that the differences due to geologic period are, in coals of the same initial classes 

of ingredient matter and conditions of biochemical action, obliterated, 

so far as may be seen in the ultimate analysis, by dynamic influences 

expressed in metamorphism and progressive devolatilization

OBLITERATION OF DISTINCTIONS AS A RESULT OF REGIONAL

METAMORPHISM.

Comparative examination of the coals assembled in the accompanying tables shows most convincingly the efficient work of the dynamochemical processes in wiping out all the important distinctions due 

to differences in the age of the fuel. Under this action the coals of 

all epochs undergo essentially the same experience, of progressive 

devolatilization, deoxygenation, and concentration, though not without great waste, of carbon and hydrogen. The closeness of the 

agreement between the corresponding advanced stages of the older 

and the younger coals is shown by their industrial adaptation as well 

as by the ultimate chemical analysis. The high-grade coking coal 

and semianthracite of the western Upper Cretaceous and Tertiary 

formations are as truly coking and semianthracite as though they 

had grown in the vast umbrageous swamps of the Paleozoic. The 

brown coals of North Dakota are progressively transformed to semibituminous and to bituminous as they extend farther within the 

regions of the increased geodynamic action which effected the further upthrust of the Rocky Mountains. The Cretaceous coals of

oCompare No. 73b (F. C. 64.39); No. 44b (V. C. 65.74); and No. 25a (F. C. 65.91).
OXYGEN ATION AND WEATHERING OF COALS. 63

the Crested Butte, Colo., region are transformed to semibituminous 

coking coals and to anthracites under dynamic influences, the chief 

of which is, I believe, horizontal thrust pressure under loading. Only 

very rarely, and in very restricted localities, is the metamorphism 

due to plutonic intrusives or overflows.

To a limited but convincing extent these changes may be followed 

in the same bed as well as in the same geologic formation and region. 

It appears only to be necessary that the coals be of the same kind at 

the beginning in each case. If xyloid lignites they become xyloid 

bituminous coals; if cannel brown coals they become bituminous 

cannels, etc. There appears to be no important difference in mode 

of formation or composition between the Upper Cretaceous cannel 

coals near Cedar Valley in Utah and those of the upper Pottsville in. 

eastern Kentucky. The dull, dense, "amorphous" bands, sometimes approaching a bastard cannel, which may not infrequently be 

observed in the Paleozoic coals of the Appalachian trough, are both, 

in their nature and in the conditions of their formation exactly like 

those similarly found in the Cretaceous and Tertiary coals arid in 

the Pennsylvania anthracites. The differences, principally relating 

to the degree of elimination of the oxygen content, mark the progress 

of the dynamochemical work in the process of coal formation.

OXYGENATION AND WEATHERING OF COALS.

CHANGES IN LOW-GRADE COALS.

Both in connection with the discussion of the causes of variance 

from the C: (0 + ash) ratio and efficiency curve, and in the review of 

the comparative standing of the H: 0 ratios in Plate III, it has been 

noted that in general the lower classes of coals take oxygen on exposure to the atmosphere. This, together with some immediate loss 

of compressed volatile matter, appears to mark the first phase of 

weathering. Later, and on prolonged exposure, there seems to be 

considerable loss of carbon and hydrogen also, especially in the 

humic (ordinary) coals.

EFFICIENCY LOSSES IN WEATHERING.

The consideration of this subject engages us only in so far as it 

obviously affects the efficiency of the ratio curve. The analytical 

data now available in the reports of the coal-testing work are unfortunately deficient as to such samples and localities as alone will 

put in the hands of geologists and engineers the data necessary for 

knowing the total efficiency losses endured by some of our thinly 

covered or long mined, not to mention weathered, coals. An inquiry 

to show the kinds, degrees, and rapidity of loss under varying conditions would require a large number of ultimate analyses; but I am 

81144 Bull. 382 09 5
THE EFFECT OF OXYGEN IN COAL.

confident that the results of a series of such observations would in 

many cases prove surprising as well as important.

The amount of oxygen that is assimilated and the rapidity with 

which it is taken up by certain subbituminous coals and lignites seem 

to indicate very unstable chemical conditions in the combustible 

matter of these coals as they lie deeply buried in the strata. It will 

later be seen that in some coals the amount of this absorbed oxygen 

exceeds the capacity of the hydrogen to form water.

LOSSES SHOWN BY ANALYSES AND RATIO-EFFICIENCY CURVE.

Mention has been made of the almost invariable calorific deficiency, 

as indicated by the curve, of-those coals that have been weathered, 

taken from shaly or thinly covered mines, or country banks, or deep 

but abandoned mines. Most of these coals are from geologic formations or regions in which the coals are exceedingly low in sulphur, so 

that many of them should show excess curve errors if wholly unaffected; and this seems to be borne out by some of the better samples 

from the same districts. The few comparisons given below are offered 

rather as suggestions and as bases for rough estimates than as careful 

calculations based on representative, not to say ample, material.

Following are the analyses of two coals from the Lewis (Cretaceous) shale, 22 and 24 miles northwest of Fort Steele, Wyo. The 

coal is subbituminous. The first, No. 53a of Table 1, is from an 

entry near the foot of the shaft; the second was taken near the 

.surface of the ground.

Comparison of two coals to show effect of weathering.

No.

53a

Wyo. 39191...

S.

0.85

.31

H.

5.16

4.90

C.

63.57

59.86

O.

22.05

29.39

Ash.

3.80

4.12

Moisture.

8.70

9.34

F. C.

55.36

55.57

H:O.

24.2

18.3

Av. H.

2.02

1.23

Calories.

6,310

5,636

Curve 

error.

+ 30 -219

a Bull. U. S. Geol. Survey No. 316, 1907, p. 256.

The second of these analyses does not differ widely from the first 

if the first be recalculated after adding 10 per cent of oxygen. The 

difference in calories between the two analyses is 674. If a lump 

allowance of 50 calories is made for difference in ash, etc., in the second, we shall have left 624 calories as a rough estimate for the loss 

in weathering. In this case the loss would be about 62 calories for 

each 1 per .cent of added oxygen. This is not far from the actual 

anticalorific value of oxygen in a coal having the same C: (0 + ash) 

ratio as 53a. The effect of the added 0 is seen both in the reduced 

H:0 ratio of the weathered specimen and in the VC: C ratio, which 

in the weathered is 19.48 as compared with 23.80 in the shaft coal. 

The fact that adding 10 per cent of oxygen to No. 53a creates a
OXYGENATION AND WEATHERING OF COALS. 65

small 'deficiency in the hydrogen, the carbon, and the Ii:0 ratio, as 

well as in the available hydrogen, indicates either some loss of carbon 

and hydrogen in the deteriorated sample or that the absorbed oxygen is a little under 10 per cent, possibly as low as 7 psr cent.

It will be borne in mind that the ratio-efficiency curve errors, 

which show large deficiencies in these deteriorated coals, may represent but portions of the real calorific losses; for the added oxygen 

has naturally had the effect of lowering the C: (0 + ash) ratios, thus 

placing them lower in the curve. It is interesting to note, however, 

that the calorimetrically ascertained efficiencies of these weathered 

coals generally exceed those calculated by Du Long's formula.

LOSSES SHOWN BY H:O AND VC:C RATIOS.

Evidence of the effects of exposure or weathering is often obvious 

in the ratios as well as in the calorific deficiencies. This is represented graphically in Plate III. Usually the drop is more conspicuous in the VC: C ratios as here tabulated. Examples of coals from 

prospects whose ratios are to be interpreted as indicating deterioration are No. 62a (F. C. 61.62) and No. 72a (F. C. 60.89), both beingbituminous coals. The subbituminous coal at Fall River, Wyo. 

No. 9a (F. C. 41.22), is placed among the brown coals below the other 

subbituminous coals in Plate III, as the result, I believe, of exposure.

A striking illustration of profound deficiencies in both ratios is 

seen in No. 2b, a subbituminous coal from the Labarge Range, Wyo. 

(F. C. 50.63), in which the H:0 ratio is but 11.1, while the VC:C 

ratio is only 17.47. More remarkable still, there is a deficiency of 

0.37 in the hydrogen necessary to form water in union with the oxygen of the coal. It therefore seems probable that part of the oxygen 

in this coal exists as CO, C02 , or atmospheric oxygen. The table 

contains three other analyses (Nos. 55a, 44a, and 39a) from the same 

formation and district. The four analyses are repeated below.

Comparison of coals from same district, to show effects of iveathering.

No.

55a

44a

39a

2b

0.84

2.10

1.14

.61

5. 68

5.74

5.39

4.45

.

63.81

01.76

62.05

48.65

0.

25.75

25.96

24. 56

38.57

Ash.

2.84

3.41

5.77

6.87

C

0+ash

2.23

2.10

2.04

1.07

No.

55a

44a

39a

2b

Moisture.

10.22

10.78

9.02

13.83

F.C.in 

pure 

coal.

53.81

52.06

56.51

50.63

VC : C.

27.94

28.85

23.37

17.47

H:0.»

28.6

29.0

27.4

11.1

Av.H.

2.46

2.50

2.32 -.37

Calories.

6,558

6,057

6,039

4,468

Curve 

error.

- 43

-140

- 90

-]50

The II: O ratio is calculated on the moisture-free basis.
66 THE EFFECT OF OXYGEN IN COAL.

Nos. 55a and 39a are from drifts, and, although probably somewhat 

affected by influences from the surface, are relatively fresh. No. 

44a, as might be suspected from its marked deficiency error, is from 

a prospect. It is presumably either deeper or newer than No. 2b, 

which is also from a prospect, since it shows less change from the 

composition of the deeper coals.

Since No. 39a, the third coal of the series, appears to agree in its 

main criteria with No. 2b, and since it may be, perhaps, safely 

regarded as not seriously weathered, it will be taken for comparison 

with the latter. A glance at the two analyses shows that the important differences between these coals concern the oxygen, the available hydrogen, and the calorific values. Examination of these 

differences makes it evident that if a little over. 20 per cent of ox}^gen 

be added to that in No. 39a and the analysis of the latter be then 

recalculated to 100 per cent, the resultant percentages will fall 

reasonably close to the corresponding elements in No. 2b without 

further compensation. It therefore seems probable that the prospect coal in a less weathered state was essentially like that of the 

drift coal, No. 39a. The increase in oxygen was, perhaps, nearer 

25 per cent. The accession of that amount of oxygen closely corresponds to the difference in the calorific values of the two coals, which 

amounts to 1,571 calories that is, nearly 65 calories to each 1 per 

cent of added oxygen. This agrees closely with the ascertained 

anticalorific value of oxygen in a coal having a C:(0 + ash) ratio 

near 2.00. Compensation for the difference in moisture, etc., in 

the coals seems to justify the conclusion that over 20 per cent of 

added oxygen has entered into combination with the fuel elements 

of the weathered coal.

It will also be observed that the assimilation of 20 per cent of 

oxygen in a coal like No. 39a will accomplish a little more than the 

extinction of its available hydrogen, causing a deficit of 0.18 in the 

amount necessary to form water. On the other hand, the elimination 

of 20 per cent of the oxygen in No. 2b, the weathered coal, will make 

available 2.13 per cent of hydrogen, which, if the analyses be recalculated to 100 per cent, will approach still closer to that of the other 

analyses.

Thus, in short, the evidence drawn from (a) the comparison of the 

analyses of the more with the less weathered fuel, (6) the probable 

loss in calorific value, and (c) the amount of the reduction of available hydrogen agrees in indicating a probable assimilation of 20 per 

cent or more of oxygen in the course of weathering. All things considered, it is perhaps safe to estimate the falling off in the efficiency 

of this subbituminous fuel at nearly one-fourth of its original heating 

power in the calorimeter.
OXYGENATION AND WEATHERING OF COALS. 67

The sample just discussed on account of its availability among 

the analyses studied in the preceding pages is not to be regarded 

as extraordinary or even unusual among weathered coals of its 

class. More strongly marked hydrogen deficiencies and more conspicuous degradations are to be found among the field samples. 0 

Analyses-of surface samples of coals of these grades are of little 

value in determining the characteristics of the coal, except in so far 

as they indicate the approximate amounts of sulphur and ash. Many 

of the analyses of coals from deep prospects and country banks are 

not to be taken as showing the real merits of the fuel.

It appears that in the lignites (brown coals) the deterioration is 

still greater; and it follows, almost as a certainty, that in some of the 

peats, particularly among the xyloid or more fibrous types, the loss 

of calorific value during the periods of drying, manufacture, and 

storage that is, between the moment of exhumation from the pit 

bottom and the time of deposition in the crucible or on the grate 

may be very serious. It may not be extreme to suggest that this loss 

possibly amounts in certain cases to as much as that incurred through 

weathering in some of the subbituminous coals.

UNDERGROUND WEATHERING.

The analyses bear evidence, according- to my tentative interpretation, that the phenomena of weathering are not confined to outcrops or shallow prospects. There are a number of coals in which I 

suspect oxygenation to have taken place to some extent in shallow 

mines or country banks and drifts which have not penetrated too far 

from the surface. An example of these is No. 2a from near Miles, 

Mont. b

A sample showing what I am inclined to interpret as oxygenation 

as the result of exposure to air for a long period in a large mine of 

good depth comes from the No. 6 mine at Rock Springs, Wyo. This 

mine is said to have been abandoned about ten years ago. The coal 

is subbituminous and of high quality, as will be observed from the 

analysis. 0

Below is given, from Table 1, the analysis (air-dried basis) of No. 

14.4, the coal from No. 10 mine at Rock Springs, Wyo., as in car 

sample at the fuel-testing plant of the United States Geological 

Survey; and following it the analysis from the abandoned No. 6 

mine, recalculated to the same percentage of moisture as No. 144.

a See analyses published in Bull. U. S. Geol. Survey No. 316. Examples are Wyoming 3C95 and 3C97, 

p. 237.

& See also No. 4a from near Glendive, Mont.; Nos. 175a, 160a, 140c, 72a, and 62a. 

"Analysis included by courtesy of Mr. M. 11. Campbell.
68 THE EFFECT OF OXYGEN IN COAL.

Comparison of coals showing effect of long exposure to air in abandoned mine.

No.

144........

Wyo.6042.

N.

1.52

1.46

S.

ORfi

.46

H.

5.37

5.01

C. '

70.30

66.32

0.

18.32

22,03

Ash.

3.63

4.72

Moisture.

6.00

6.00

Calories.

6,955

6,340

H:0.

36.2

26.1

Av. H.

3.08

2.23

VC:C.

26.49

15.41

F.C.

57. 19

62.88

If to sample 144, from the active mine, we add 5 per cerit of oxygen 

and recalculate to a basis of 100 per cent, .compensating the calorific 

value, we have:

Recalculation of analysis of sample 144.

Nitrogen.................. 1.45

Sulphur................... .82

Hydrogen.................. 5.11

Carbon.................... 66.95

Oxygen.................... 22.21

Ash:........................ 3.46

Moisture................... 5.71

Calories................:... 6,624

H:0 ratio.................. 26.3

Available hydrogen......... 2. 33

-This analysis, as will at once be recognized, approaches substantially that of the sample from the abandoned mine. In nitrogen, 

carbon, and hydrogen the agreement is satisfactorily close, as is also 

the amount of available hydrogen, which becomes 2.33 compared 

with 2.23. In fact, the agreement between the recalculated No. 144 

and the abandoned-mine analysis is sufficiently close to justify the 

conclusion that, together with the other presumable changes, 5 per 

cent or more of oxygen had probably been assimilated in the coal 

deep in the' old mine on account of exposure to air since its abandonment. The difference in the calorific value is disproportionate to 

that which might reasonably be expected from the mere addition of 

5 per cent of oxygen, and offers ground for the suspicion that there, 

has been a small loss in carbon and hydrogen. The calorific difference, roughly compensated for difference in ash and sulphur, amounts 

to about 535 calories, or about 105 to each 1 per cent of assumed 

oxygen increase. This, as shown on page 40, is probably as much as 

10 calories in excess for added oxygen.

It is probable that in the subbituminous coals, and more especially 

in the lignites, oxygenation begins immediately after the coal is 

blasted from the face in the mine. Zincken a quotes Bischoff to the 

effect that the brown coal of Putzchen absorbed 11 per cent of oxygen 

from the atmosphere in eight days. More recently Stremme and 

Spate b have shown some absorption even by sapropelic coals standing for various periods in a museum. It should be noted, however, 

that the sapropelic or alga coals are very much less susceptible tooxidation on exposure than are the more bituminous coals, which, 

are humic.

a Physiographic der Braunkohlen, 1867, p. 8. See also Muck, Chemie der Steinkohlen, 1891, p. 109. 

b Zeitschr. angew. Chemie, vol. 20, pt. 43, 1907, p. 1841; also Zeitschr. Deutsch. geol. Gesell., Monatsber., 

Nos. 7 and 8,1907.
OXYGENATION AND WEATHERING OF COALS. 69

It is not impossible that some of our peats will be found to assimilate still greater quantities of oxygen on exposure. This question, as. 

well as that of the immediate loss of volatile in freshly mined lignites 

or subbituminous coals, is one deserving careful examination. The 

results of the very interesting, as well as important, investigations 

recently published by Parr and Hamilton," show that deterioration 

is strongly marked and rapid, even within short periods, in coals soold and well established in coal formation as those of the Illinois; 

region, where an efficiency of 2 to 10 per cent may be lost on exposure 

for seven months. A still greater susceptibility to change is, I. 

believe, to be expected in the higher-grade bituminous coalso of some 

portions of the western Mesozoic and Tertiary coal fields, in which 

the dynamic influence is still in vigorous action, locally at least, as 

shown by rapid loss of volatile, and in which, on account of lack of 

time in which the volatile might effect its escape (with concomitant 

readjustment of compounds to comparative equilibrium in conformity 

to the new conditions), it may be assumed that the hydrocarbon 

compounds are in a state of highly unstable equilibrium. The susceptibility to deterioration is doubtless far greater in many of the subbituminous coals and lignites.

LOSSES BY WEATHERING IN SHIPMENT.

A comparison of the calorific values of the car samples with the 

ratio curve on the one hand and with a few mine samples collected 

by the field geologists on the other, seems to me to warrant the 

apprehension that in some samples at least a considerable deterioration has occurred before the actual analysis of the fuel. My personal 

opinion, based upon quite insufficient data, is that the car samples of 

most of these lignites and of many of the subbituminous coals are 

calorifically deficient to an extent of 50 calories as compared to the 

probable efficiency of freshly mined and tightly sealed mine samples/ 

provided the latter are analyzed immediately upon opening. It may 

not be overhazardous to estimate that some of the published calorific 

values are as much as 200 calories less than the efficiency of the coal 

in the ground. The coal No. 5la, from Batan Island, P. I., may be 

mentioned as a good example of probable loss between the coal bed 

and the crucible. Analyses Nos. 3, 13, 19, 22, 32, 56, S3, and 144 also 

appear to justify suspicion.

The amount of loss depends not only upon the kind of coal, but 

also on the conditions of loading, the kmd of car, the size of the 

fragments, the weather, the period of transit (which for many coals 

is over three weeks), and the mode of sampling from the car. The 

present method'of air drying the coal in an oven under a current of

. Geology, vol. 2, 1907, p. C93.
70 THE EFFECT OF OXYGEN IN COAL.

warm air in the laboratory may also be mentioned as seeming most 

favorable to the oxygeiiation of the fuel and its consequent rapid 

calorific deterioration.

For commercial purposes the current methods of sampling and 

analysis appear to be very satisfactory and even indispensable, since 

they show the composition of the coal as it is ordinarily received at 

its industrial destination. Yet it is possible that a thorough investigation of the impairment of the lowest-grade fuels on exposure will 

show a calorific loss in -some coals that is so great within a short 

time as perhaps to call for new methods of handling.

The above observations, it must be remarked, are disconnected and 

fragmentary, and crude both as to methods and results. Their purpose is mainly to stimulate observation. I anticipate, however, that 

properly made tests and careful calculations, based on adequate data, 

will show the importance of the subject to have been on the whole 

understated.

SUMMARY.

1. Coals with high oxygen and low ash will, in general, have very 

nearly the same efficiency in the calorimeter as other coals with alternated percentages, low oxygen and high ash, if the total carbon is 

the same. This applies to both air-dried and moisture-free coals.

2. Oxygen and ash are of very nearly equal anticalorific or negative value, ash being probably slightly more injurious in most coals; 

the negative value of the oxygen of moisture is not far different from 

that of the oxygen combined in the coal. -

3. The calorific value of coals in general is essentially indicated by 

the balance between the total carbon, on the one hand, and the sum 

of the two great impurities, oxygen and ash, on the other, the hydrogen, nitrogen, and sulphur being usually negligible as " constants."

4. Except in the presence of unusual variations of hydrogen or sulphur, the efficiencies of the coals, if ash be constant, rank nearly 

in the order of the ratios C: 0, which in each kind of coal marks the 

progress of coal formation under dynamochemical influences.

5. Oxygen and ash being of approximately equal anticalorific potency the efficiencies of the coals conform fairly closely to the order 

of the ratios C: (0 + ash), so that among coals of all kinds those having the same ratios are found to have not far from the same efficiency. 

The causes of the greater departures are mentioned in the next 

paragraph.

6. A miscellaneous series of coals of all kinds, ages, and regions, 

when platted according to theC:(O + ash) ratios and calorific values as components, describe a curve to which they conform very 

closely, the average variance being less than 1 per cent of the calorific value. The greatest variances are among (a) weathered coals, (6)
SUMMARY. 71

those having 79 per cent or more of fixed carbon in pure coal that is, 

those undergoing anthracitization and (c) the boghead-cannel group, 

in which the hydrogen is excessively high, so that the efficiencies 

describe a higher curve characteristic of the group.

7. The departures from the ratio-efficiency curve on account of 

unusually high or low available hydrogen are generally not large. 

High sulphur is usually attended and compensated by high hydrogen, the converse being true to a less extent. Unusually high sulphur 

acts, on the whole, as a diluent, while very low sulphur leaves the 

relative field to the heat-determining elements. Consequently the 

variances from the curve on account of the neglected constants 

hydrogen, sulphur, and nitrogen are rarely over 2 per cent unless in 

the exceptions noted in paragraph 6.

8. Types of coals are initially determined by the nature of the ingredient matter, the conditions of deposition, and the extent of 

operation of the first or biochemical process in coal making; but progressive devolatilization, lithification, cleavage, and other accompanying alterations result from the second or dynamochemical stage 

of coal formation, which in each kind removes the essential distinctions of age or region, even .tending ultimately to obliterate the differences in kind. Consequently any classification of coals based on 

the present form of ultimate analyses must be arbitrarily defined. 

There is intergradation in all parts of the process of coal conversion 

and coal alteration, as well as in the ingredient matter and conditions 

of deposition.

9. The weathering of the lower grades of coal, especially the lignites, bituminous coals, and peats, is marked by the accession of oxygen, which is taken into combination. This increase of the oxygen 

contents, which seems to indicate lack of equilibrium in the hydrocarbon compounds of the normal coal, readily permits a calorific deficiency, which, on account of the high anticalorific value of oxygen, 

is often serious. It is possible that in many cases considerable increase of oxygen and consequent loss of efficiency are suffered by the 

lower-class fuels between removal from the bed and deposit in the 

grate or the chemical crucible.

10. The adaptability of a coal to coking by the ordinary process 

appears to be indicated with a fair degree of certainty by the ratio 

of the hydrogen to the oxygen, moisture-free basis. Practically all 

coals with H:0 ratios of 59 (per cent) or over seem to possess the 

quality of fusion and swelling necessary to good coking. Most 

coals with ratios down to 55 will make coke of some kind, while a 

few coals with ratios as low as 50 coke in the beehive oven, though 

very rarely producing a good article. The coking property seems 

to depend, not so much on the amount of available hydrogen, which 

is a very imperfect index of the proportion of the elements in the
72 THE EFFECT OF OXYGEN IN COAL.

volatile, but on the relative amount of the hydrogen as compared 

to that of the oxygen. In those coals undergoing change to anthracite, the hydrogen-oxygen ratio may fail as a guide; the failures 

appear, however, to be readily distinguished by the marked calorific 

deficiencies shown by the C:(0 + ash) ratio and efficiency curve. 

The data examined, though insufficient to serve as a basis for a 

conclusion, seem to point toward the need of a relatively high carbon element in the remaining volatile combustible of coals with 

79 per cent or more of fixed carbon (pure coal), in order to secure 

either the best coking results or the calorific efficiency indicated by 

the C: (0 + ash) ratio-efficiency curve.
PARTIAL BIBLIOGRAPHY.

SURVEY PUBLICATIONS ON COAL.

A bibliography of United States Geological Survey publications 

containing references to coal is. given in Bulletin 341, Contributions 

to Economic Geology, 1907, part 2, pages 419-436. The following 

publications treating of the work of the Survey fuel-testing plants 

contain many analyses of coals. The Survey's supply .of those 

designated by an asterisk is exhausted, but they can be purchased 

from the Superintendent of Documents, Government Printing Office, 

at the prices named. Copies of the others can be obtained free by 

applying to the Director of the Geological Survey.

BULLETIN 261.* Preliminary report on the operations of the coal-testing plant 

of the United States Geological Survey at the Louisiana Purchase Exposition, St. Louis, 

Mo., 1904; E. W. Parker, J. A. Holmes, M. R. Campbell, committee in charge. 1905. 

172 pp. 10 cents.

PROFESSIONAL PAPER 48.* Report on the operations of the coal-testing plant of 

the United States Geological Survey at the Louisiana Purchase Exposition, St. Louie, 

Mo., 1904; E. W. Parker, J. A. Holmes, M. R. Campbell, committee in charge. 1906. 

In three parts. 1492 pp., 13 pis. $1.50.

BULLETIN 290.* Preliminary report on the operations of the fuel-testing plant of 

the United States Geological Survey at St. Louis, Mo., 1905, by J. A. Holmes. 1906. 

240 pp. 20 cents.

BULLETIN 323.* Experimental work conducted in the chemical laboratory of the 

United States fuel-testing plant at St. Louis, Mo., January 1, 1905, to July 31, 1906,. 

byN.W. Lord. 1907. 49pp. 10 cents.

'BULLETIN 332. Report of the United States fuel-testing plant at St. Louis, Mo., 

January 1, 1906, to June 30, 1.907; J. A. Holmes in charge. 299 pp.

BULLETIN 336.* Washing and coking tests of coal- and cupola tests of coke conducted by the United States fuel-testing plant at St. Louis, Mo., January 1, 1905, 

to June 30, 1907, by Richard Moldenke, A. W. Belden, and G. R. Delarnater, with 

introduction by J. A. Holmes. 1908. 76pp. 10 cents.

BULLETIN 362.* Mine sampling and chemical analyses of coals tested at the United! 

States fuel-testing plant, Norfolk, Va., in 1907, by J. S. Burrows. 1908. 23 pp. 

5 cents.

BULLETIN 363. Comparative tests of run-of-mine and briquetted coal on locomotives, including torpedo-boat tests and some foreign specifications for briquetted 

fuel, by W. F. M. Goss. 1908.' 57 pp., 4 pis.

BULLETIN 368. Washing and coking tests of coal at Denver, Colo., by A. W. Beklen, 

G. R. Delamater, and J. W. Groves. 1909. 54 pp., 2 pis.

73
74 THE EFFECT OF OXYGEN IN COAL.

MISCELLANEOUS RECENT PUBLICATIONS.

The following books and papers treat of the composition of coals:

1905.

DONATH, ED., Betrachtungen iiber das Backen und iiber die Bildung des Steinkohle, Oesterr. Zeitschr. Berg, und Hiittenwesen, January 11, 18, 25.

FULTON, J., Coke, A treatise on the manufacture of coke and other prepared fuels. 

Scran ton.

POTONIE, H., Die Entstehung der Steinkohle und verwandter Bildung einschliesslich 

des Petroleums. Berlin. 45 pp.

1906.

BEMENT, A., The sampling of coal. Jour. Am. Chem. Soc., vol. 28, pp. 632-639. 

CAMPBELL, M. R., The classification of coals. Trans. Am. Inst. Min. Eng., vol. 36,

pp. 324-340. 

FRAZER, PERSIFOR, The classification of coals. Trans. Am. Inst. Min. Eng., vol. 36,

pp. 825-833. 

PARR, S. W., Composition and character of Illinois coals. Bull. Illinois State

Geol. Survey No. 3.

 The classification of coals. Jour. Am. Chem. Soc., vol. 28, pp. 1425-1432. 

Also Mines and Minerals, December.

1907.

DIRKE, H, B., Illinois coal tests. Eng. Record, February 25.

GREENWELL, A., and ELSDEN, J. V., Analyses of British coals and coke and the

characteristics of the chief coal seams worked in the British Isles. London.

405 pp.

GROUT, F. F., The composition of coal. Econ. Geology, April-May, pp. 225-241. 

HEADDEN, W. R., A study of some Colorado coals. Proc. Colorado Sci. Soc., vol. 8,

pp. 281-300.

KEIGHLEY, F. C., Why do some coals coke? Mines and Minerals, October. 

MAcCALLUM, H., The classification of coal. Canadian Min. Jour., May 1. 

MUCK, F., Die chemie der Steinkohle. Leipzig. 66 pp. 

PARR, S. W., Heat production and the constituents of coal. Eng. and Min. Jour.,

June 29. 

PARR, S. W., and HAMILTON, N. D., The weathering of coal. Econ. Geology,

October-November, pp. 692-703.

 The weathering of coal. Bull. No. 17, Univ. Illinois Eng. Exper.

Sta., 37 pp. 

POTONIE, H., Historiches zur Frage nach der Genesis der Steiukohle. Naturw.

Wochenschr., vol. 6, pp. 113-117. 

WOODMAN, J. E., Coal sampling. Canadian Min. Jour., May.

1908.

CAMPBELL, M. R., A practical classification of low-grade coals. Econ. Geology, 

March-April, pp. 134-142.

DOWLING, D. B., Classification of coals by the split volatile ratio. Canadian Min. 

Jour., April 15, pp. 143-146. .

PISHEL, M. A., A practical test for coking coal. Econ. Geology, June-July, pp. 

265-270.

PORTER, F. C., and OVITZ, F. K., The nature of the volatile matter in coal as evolved 

under different conditions. Jour. Am. Chem. Soc., vol. 30, pp. 1486-1507.

WHITE, DAVID, Some problems in the formation of coal. Econ. Geology, JuneJuly, pp. 292-318.

o