NBS MONOGRAPH 10

The "1958 He' Scale of Temperatures"

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
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Errata to Accompany

4 NBS Monograph 10, The "1958 He Scale of Teraperatur es"

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USCOMM-NBS-DC January 22, 1968
i
UNITED STATES DEPARTMENT OF COMMERCE • Frederick H. Mueller, Secretary

NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director

The "1958 He* Scale of Temperatures"

Part 2. Tables for the 1958 Temperature Scale

H. van Dijk, M. Durieux, J. R. Clement, and J. K. Logan

Reprinted from the Journal of Research of the National

Bureau of Standards—A. Physics and Chemistry, Vol. 64A,

No. 1, January-February 1960.

National Bureau of Standards Monograph 10

Issued June 17, 1960

Part 1. Introduction

F. G. Brickwedde

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. - Price 20 cents
Contents

Page

Part ]. Introduction 1 References 4

Part 2. Tables for the 1958 temperature scale 4

1. Introduction 4

2. Constants used in the computation of the scale 5

3. Fixed points on the scale 5

4. Comments on determining temperature by measuring vapor pressure. _ 5

Table I. Vapor pressure of He* (1958 scale) in microns 10~' mm) mercury at

0° C and standard gravity (980.665 cm/sec^) 5

Table II. 1958 He* vapor pressure-temperature scale, T in ° K as a function

of P in millimeters mercury at 0° C and standard gravity, 980.665 cm/sec^. - 12

Table III. 1958 He* vapor pressure-temperature scale, T in ° K as a function

of P in centimeters mercury at 0° C and standard gravity, 980.665 cm/sec^. _ 15

Table IV. Temperature derivative, dP/dT, in millimeters Hg/° K for the 1958

He* vapor pressure-temperature scale, P in millimeters mercury at 0° C and

standard gravity, 980.665 cm/sec^ ^ 15

Table V. Auxiliary table for use in making hydrostatic head correction.- 16

Table VI. Deviations of earlier scales from the 1958 scale, Tn-T^i in milli- degrees 16

Table VII. Auxiliary table for use in making corrections for density of mercury at temperatures other than 0° C 17

Equation for computing local acceleration due to gravity 17
The "1958 He^ Scale of Temperatures"

Part 1. Introduction

F. G. Brickwedde ^

Part 2. Tables for the 1958 Temperature Scale

H. van Dijk,2 M. Durieux,^ J. R. Clement,^ and J. K. Logan ^

(Revision: May 1, 1959)

The generally used practical scale of temperatures between 1° and 5.2° K is the He*

vapor pressure scale based on an accepted vapor pressure equation or table. In Sevres

(near Paris), October 1958, the International Committee on Weights and Measures recom- mended for international use the "1958 He* Scale" based on a vapor pressure table arrived

at through international cooperation and agreement. This table resulted from a consideration of all reliable He* vapor pressure data obtained using gas thermometers, and paramagnetic susceptibility and carbon resistor thermometers. The theoretical vapor pressure

equation from statistical thermodynamics was used with thermodynamic data on liquid

He* and the vapor equation of state to insure satisfactory agreement of the vapor pressure

table with reliable thermodynamic data.

Part 1. Introduction

The International Committee on Weights and

Measures at a meeting in Sevres (near Paris), France,

September 29 to October 3, 1958, approved the

"1958 He* Vapor Pressure Scale of Temperatures"

as an international standard for thermometry from

1° to 5.2° K. This was the culmination of several

years of intensive research and cooperation on the

helium vapor pressure scale at the Kamerlingh Onnes

Laboratory in Leiden, Holland, and the U.S. Naval

Research Laboratory in Washington.

The vapor pressure of liquid He* has for a long

time been used as a standard for thermometry between 1° and 5.2° K. The first measurements of

thermodynamic temperatures in the liquid He* range

were made with constant volume gas thermometers

filled with He*. Simultaneous measurements of the

vapor pressure of liquid helium in temperature equilibrium with the gas thermometer established a vapor

pressure-temperature relation which then was used

as the basis for determining thermodynamic temperatures from vapor pressure measurements. With

these vapor pressure-gas thermometer measurements

there were measurements of He* vapor pressures

made simultaneously with measiu-ements of the He*

isotherms from which temperatures were obtained

by extrapolating the isotherms to zero density

(A^/F—>0) in accordance with the virial equation of

state

pVIN=B.T[l-{-B {N1V) + C {Nl\y+ . . .] (1)

• Consultant to NBS. Permanent address: College of Chemistry and Physics,

Pennsylvania State University, University Paris:, Pa.

2 Kamerlingh Onnes Laboratory, Leiden, Netherlands.

3 U.S. Naval Research Laboratory, Washington, D.C.

After the latent and specific heats of liquid He*

had been measured, the experimental vapor pressuretemperature relation was improved through the use

of the theoretical vapor pressure (P) equation:

In F=i>.-^+\ In T-^

J^''

S, dT

where

{2nrmY'^k^'^lh? (.3) and

a=ln (PV/NRT)-2B {N/V)-(%) C {N/V)\ (4)

Lq is the heat of vaporization of liquid He* at 0° K,

Si and Vi are the molar entropy and volume of

liquid He*, m is the mass of a He* atom, 5 and Care

the virial coefficients in eq (1), and the other symbols have their usual meaning. Both theoretically

calculated and directly measured vapor pressures

were considered in arriving at the 1958 He* Temperature Scale.

Equation (2) presupposes that the thermodynamic

properties entering the equation have been measured

on the thermodynamic scale, otherwise the use of

this equation for the calculation of P is not valid.

In practice, however, these properties are measured

on an empirical scale that only approximates the

thermodynamic scale. In general this empirical

scale has been a He* vapor pressure scale based on

gas thermometer measurements.

1
As T is lowered, the fourth, fifth, and sixth terms

in eq (2) become smaller and less important relative

to the first three terms. At 1.5° K, the inclusion or

exclusion of the sum of the fourth, fifth, and sixth

terms in eq (2) afi^ects the temperature calcidated

from a given value of P by only 0.0005 deg. It

may be said then, that below 1.5° K, the vapor

pressure of He* is in effect really determined, within

the present accuracy of the vapor pressure measure- ment, by a single empirical constant, the heat of

vaporization of liquid He* at 0° K. At present, Lo

for He* is normally calculated from vapor pressure

data obtained with a gas thermometer. The magnitude of the last three terms in eq (2) increases

rather rapidly with rising T, and above the X-point

(2.172° K) the accuracy of the evaluation of these

terms is a very important consideration.

In Amsterdam in 1948, on the occasion of a General Assembly of the International Union of Physics, a small group of low temperature physicists, meeting informally, agreed to use and recommend for

temperature measurements between 1° and 5.2° K,

a table of vapor pressures of He*, then in use in

Leiden, which came to be known as the "1948 Scale"

[1].* This scale has sometimes been referred to as the "1949 Scale". From 1 ° to 1 .6° K, the "1948 Scale"

was based on vapor pressmres calculated by Bleaney

and Simon [2] using eq (2). From 1.6° to 5.2° K,

the scale was based on measured vapor pressures

and temperatiu-es determined with gas thermometers.

From 1.6° to 4.2° K, it was based primarily on the

vapor pressure measurements of Schmidt and

Keesom [3]. Even in 1948, when the "1948 Scale" was agreed

to, there was evidence in the measurements and calculations of Kistemaker [4] that the "1948 Scale"

deviated significantly from the thermodynamic scale.

However, it was thought at the time that, on general

principles, indicated changes in an existing scale

should be made only after these changes had been

confirmed. With improvements in the precision and

accuracy of physical measurements at low temperatures, irregularities appeared in the temperature

variation of physical properties between 1° and 5° K

that were in the main reproducible in different substances and properties and were, therefore, attributable to errors in the "1948 Scale" [5]. Stimulated

by these results which corroborated Eastemaker's

work, the investigations of the He* vapor pressure

scale were undertaken that culminated in the "1958

He* Scale."

Paramagnetic susceptibility and carbon resistor

thermometers were later employed in investigations

of the He* vapor pressure-temperature relation [6]. These thermometers were used for the interpolation

of temperatures between calibration points (temperatures) using an assumed relation connecting temperature and paramagnetic susceptibHity or carbon

resistance for the calcidation of the temperatures.

Figures In brackets indicate the literature references on page 4.

For suitably chosen paramagnetic salts, the CurieWeiss Law was assumed to hold:

where X is the magnetic susceptibility and C and A

are empirical constants. Measurements at two temperatures would suffice to determine these two empirical constants if the measurement were reaUy of X

or a quantity directly proportional to X. However, a

calibration of the paramagnetic thermometer at a

third calibration temperature is necessary because

the arbitrariness in the size and arrangement of the

paramagnetic salt samples and the induction coils

that surround the salt sample for the susceptibility

measurement make the measurement a linear function of X. Interpolation equations for carbon resistor

thermometers are not as simple as eq (5) and do not

have a theoretical basis. Hence, vapor pressure

data obtained with carbon resistor thermometers are

of more limited usefulness for the determination of

the He* vapor pressure-temperature relation . Clement

used carbon thermometer data to examine the derivative d {\nP)l d {IIT),[1].

Important use has been made of He* vapor pressure

measurements made with magnetic susceptibility and

carbon resistor thermometers in arriving at the "1958

He* Scale." These vapor pressm-e measurements

were considered along with those made with gas

thermometers and vapor pressures calculated using

eq (2). Temperature measurements with magnetic

and carbon resistor thermometers are much simpler

to make than measurements with gas thermometers,

and hence vapor pressure data obtained with magnetic and carbon resistor thermometers are more numerous. Also, the measurements made with these

secondary thermometers are more precise (to be distinguished from accm-ate) which makes them especially useful for interpolation between the gas thermometer data.

There are, accordingly, three practical methods

for determining the He* vapor pressure-temperature

relation: (1) By use of the direct vapor pressure

measurements made with gas thermometers, (2)

through the use of eq (2) with some vapor pressiiregas thermometer data, and (3) through the use of

vapor pressure measurements with secondary thermometers which have been cahbrated using some gas

thermometer data. If aU the pertinent experimental

data were accvirate and all temperatures were on the

thermodynamic scale, these three methods would

yield results in good agreement with each other, and

any one might be relied upon for the construction

of the He* vapor pressure-temperature table defining

the scale. Because of experimental errors, however,

the vapor pressures obtained by the different methods

differ when carried to the limit of the sensitivity of

the measurements. For He* between 1° and 4.5° K,

different choices of the methods and different selections of the experimental data used, weighting factors

and corrections to the published data yield scales

aU within about 4 millidegrees of each other. The

2
primary evidence for this is that 4 millidegrees is the

maximum difference between the L55 Scale [8] obtained by method (2) and the 55E Scale [9] obtained

by method (3) . This then is a measure of the range

(total spread) of uncertainty at present in the He^

vapor pressure scale of temperatures between 1°

and 4.5° K.

All published He* vapor pressure measurements,

and thermodjmamic data needed for eq (2) were

independently studied and correlated by H. van

Dijk and M. Durieux at the Kamerlingh Onnes

Laboratory in Leiden [8] and by J. R. Clement and

J. K. Logan at the U.S. Naval Research Laboratory

in Washington [9]. As far as possible, the experimental data of the original investigators were

recalculated on the basis of later knowledge of the

temperature scale, fundamental constants, and the

properties of He*. In some cases, limitations were

imposed on these recalculations by the incomplete

reporting of the experimental data by the original

investigator.

After working independently. Van Dijk and

Clement cooperated to compromise their differences.

They met first in Leiden, August 1955 and later in

Washington, summer of 1957. From January 22 to

March 14, 1958, Logan worked at Leiden, and later

represented Clement at a conference in Leiden, June

1958, at which agreement was reached on the "1958

He* Scale." This cooperation was an important

factor in the improvement of the scale.

Where the differences between the values obtained

by handling the experimental data differently are

largest (4 millidegrees), the "1958 Scale" falls

between the extremes. At other places it is close to

the mean of these values and at no place does it deviate by more than 2 millidegrees from the mean.

The estimated uncertainty of the "1958 He* Scale"

is accordingly ±2 millidegrees between 1° and

4.5° K. At higher temperatures, the estimated

uncertainty is larger.

Now that the International Committee on Weights

and Measures has recommended the "1958 He*

Scale" as an international standard it is presumed

that henceforth the International Committee on

Weights and Measures wUl take the initiative in

improving the scale when changes are needed.

Before the International Committee on Weights and

Measures assumed responsibility for the He* vapor

pressure scale, the Commission on Very Low Temperature Physics in the International Union of Pure

and Applied Physics concerned itself with the scale.

This began with the informal meeting in Amsterdam

in 1948 that resulted in the "1948 Scale." At the

Low Temperature Conferences sponsored by the

Commission on Very Low Temperature Physics of

the International Union of Physics at Paris in 1955,

and at Madison, Wisconsin, in 1957, sessions were

held at which the He* vapor pressure scale of temperatures was discussed.

The National Bureau of Standards sponsored

meetings, for discussion of the helium vapor pressure

scale of temperatures, held at the NBS during the

spring meetings of the American Physical Society

in Washington, 1955 and 1957. Also, the NBS

encouraged cooperation in reaching national and

international agreement on the scale. It initiated or promoted the meetings for discussion of the

differences between the L55 and 55E Scales proposed

respectively by Van Dijk and Durieux, and by

Clement. These were the meetings held August 26

and 27, 1955 in Leiden (before the Low Temperature Conference in Paris) [10], July 30, 31, and

August 1, 1957 in Washington (before the Low

Temperature Conference in Madison) [11], and June

13, 14, and 16, 1958 in Leiden (before the meeting

of the Advisory Committee on Thermometry of the

International Committee on Weights and Measures

in Sevres) [12]. Also, the National Bureau of

Standards promoted the arrangement which sent

Dr. Logan of the U.S. Naval Research Laboratory

to work in the Kamerlingh Onnes Laboratory from

January 22, to March 14, 1958.

The Scale agreed upon at Leiden, June 13 to 16,

1958 was presented to the Advisory Committee on

Thermometry of the International Committee on

Weights and Measiu-es at its meeting in Sevres,

June 20 and 21, 1958. The recommendation of the

Advisory Committee to the International Committee

was as follows [12]:

"Le Comite Consultatif de Thermom6trie,

"ayant reconnu la necessite d'etablir dans le

domaine des tres basses temperatures une echeUe de

temperatmre unique,

"ayant constate I'accord general des sp6eialistes

dans ce domaine de la physique,

"recommande pour I'usage general l'"EcheUe

*He 1958," basee sur la tension de vapeur de Thulium,

comme definie par la table annexee. "Les valeur des temperatures dans cette echelle

sont designees par le symbole Tsg."

The table of He* vapor pressures that was sent

to the International Committee with this recommendation was the table distributed at the Kamerlingh Onnes Conference on Low Temperature

Physics at Leiden, June 23 to 28, 1958. It was

published in the Proceedings of the Kamerlingh

Onnes Conference [13].

On the recommendation of its Advisory Committee

on Thermometry, the International Committee on

Weights and Measures approved the "1958 He*

Scale of Temperatures" at its meeting at Sevres,

September 29 to October 3, 1958.

The table adopted by the International Committee on Weights and Measures was a table of

vapor pressures at hundredth degree intervals. This

table was expanded by Clement and Logan making

table I of this paper with millidegree entries.

Table I was inverted to give tables II and III which

express T as a function of vapor pressures. Auxiliary

tables were added including a table of the differences

between the 1958 Scale and other earlier used

scales. Linear interpolation is valid for all tables

except at the lower temperature end of table IV.
The assistance at Leiden of H. ter Harmsel and C.

van Rijn, students of Dr. H. van Dijk at the Kamerlingh Onnes Laboratory, with the computations for

the defining and auxihary tables is gratefully

acknowledged.

Various members of the Cryogenics Branch of the

Naval Research Laboratorj^ at Washington assisted

with numerous calculations which contributed toward

the development of the present scale. This assistance, especially that of Dr. R. T. Swim, is gratefully

acknowledged.

References

[1] H. van Dijk and D. Shoenberg, Nature 164, 151 (1949);

Proces-Verbaux du Comity Consultatif de Thermometrie aupres du Comite International des Poids et Mesures, session de 1952, p. T151 (Gauthier-Villars,

Paris, France).

[2] B. Bleaney and F. Simon, Trans. Faraday See. 35, 1205

(1939).

[3] G. Schmidt and W. H. Keesom, Leiden Comm. 250b

and c, Physica 4, 963 and 971 (1937).

[4] J. Kistemaker and W. H. Keesom, Leiden Comm. 269b

and c, Physica 12, 227 and 272 (1946) ; J. Kistemaker,

Leiden Comm. SuppL 95a, Physica 12, 281 (1946).

[5] See: H. van Dijk, Proc. Intern. Conf. Physics Verv Low

Temp., Mass. Inst. Technol., p. 118 (1949); R. D.

Worley, M. W. Zemansky, and H. A. Boorse, Phys.

Rev. 93, 45 (1954) ; R. A. Erickson and L. D. Roberts,

Phys. Rev. 93, 957 (1954); J. R. Clement, Phys. Rev.

93, 1420 (1954) ; R. Berman and C. A. Swenson, Phvs.

Rev. 95, 311 (1954); W. E. Keller, Phvs. Rev. 97,

1 (1955), 98, 1571 (1955), and 100, 1790 (1955); H. van Dijk, Temperature, its measurement and control

2, p. 199 (Reinhold Publishing Corp., New York,

N. Y., 1955) and Leiden Comm. Suppl. 112c; W. S. Corak, M. P. Garfunkel, C. B. Satterthwaite, and A. Wexler, Phys. Rev. 98, 1699 (1955); J. R. Clement,

J. K. Logan, and J. Gaffney, Phys. Rev. 100, 743

(1955); E. Ambler and R. P. Hudson, J. Research

NBS 56, 99 (1956) RP2654, and 57, 23 (1956) RP2689.

[6] H. van Dijk, Proc. Intern. Conf. Phvsics Very Low

Temp., Mass. Inst. Technol., p. 118 (1949); R. A. Erickson and L. D. Roberts, Phys. Rev. 93, 957

(1954); H. van Dijk, Temperature, its measurement

and control 2, p. 199 (Reinhold Publishing Corp., New

York, N.Y., 1955) and Leiden Comm. Suppl. 112c; E. Ambler and R. P. Hudson, J. Research NBS 56, 99

(1956) RP2654 and 57, 23 (1956) RP2689; H. van

IDijk and M. Durieux, Progress in low temperature

physics, vol. II, chap. XIV (North-Holland Publishing Co., Amsterdam, Netherlands, 1957).

[7] J. R. Clement, Low temperature physics and chemistry,

Proc. Fifth Intern. Conf., p. 187 (Univ. Wis. Press,

Madison, Wis., 1958).

[8] H. van Dijk and M. Durieux, Proc. Conf. Physics Low

Temp., Paris, 1955, p. 595 (Annexe 1955-3, Suppl. au

bulletin de I'lnstitut Intern, du Froid, Paris) ; Progress

in low temperature physics, vol. II, chap. XIV

(North-HoUand Pubhshing Co. , Amsterdam, Netherlands,

1957); and Leiden Conam. Suppl. 113c, Physica 24, 1 (1958).

[9] J. R. Clement, J. K. Logan, and J. Gaffney, Proc. Conf.

Physics Low Temp., Paris, 1955, p. 601 (Annexe

1955-3, Suppl. au bulletin de I'lnstitut Intern, du

Froid, Paris) ; Phys. Rev. 100, 743 (1955) ; U.S. Naval

Research Rept. 4542 (Wash., May 1955) ; Liquid

helium vapor pressure-temperature scale, rept. compiled by J. R. Clement, distributed at the Baton

Rouge, La. Conf. Low Temp. Physics and Chem.

(Dec. 1955) ; J. R. Clement, Low temperature physics

and chemistrv, Proc. Fifth Intern. Conf., p. 187 (Univ.

Wis. Press, Madison, Wis., 1958).

[10] F. G. Brickwedde, Report on the conference agreement

on the helium vapor pressure scale of temperatures,

Proc. Conf. Physics Low Temp., Paris, 1955, p. 608

(Annexe 1955-3, Suppl. au bulletin de L'Institut

Intern, du Froid, Paris").

[11] See F. G. Brickwedde, Physics Today 11, 23 (1958).

[12] F. G. Brickwedde, Physica 24, Suppl. p. S 128 (1958).

[13] H. van Dijk, M. Durieux, J. R. Clement, and J. K.

Logan, Physica 24, SuppL, S 129 (1958); H. van Dijk

and M. Durieux, Leiden Comm. Suppl. 115a, Physica

24, 920 (1958); Proces-Verbaux des Seances du Comity

International des Poids et Mesures—2= Serie, tome

26-A, Annexe T22 in the Proces-Verbaux des Seances,

5"= Session (1958) du Comite Consultatif de Thermometrie.

Part 2. Tables for the 1958 Temperature Scale

H. van Dijk, M. Durieux, J. R. Clement, and J. K. Logan

1. Introduction

The tables which follow are these

Table I. Vapor pressure of He* (1958 Scale) in

microns (10~^ mm) mercury at 0° C and standard

gravity (980.665 cm/sec^). This table is an expanded

version, with pressure values at millidegree intervals,

of the table which defines the vapor pressure on the

1958 scale at 10-millidegree intervals.

Table II. 1958 He* vapor pressure-temperature

scale, T in °Kas ajunction q/P in millimeters mercury

at 0° C and standard gravity. This table is an inversion of table I for appropriate ranges of pressures

and pressure intervals. Since this table contains

differences between successive entries, it furnishes a convenient means for converting a measured vapor

pressure to a temperature within 0.1 millidegree.

Table HI. 1958 He* vapor pressure-temperature

scale, T in °Kas ajunction ojP in centimeters mercury

at 0° C and standard gravity. This table is an extension of table II for pressures greater than 80 cm

mercury. It is numbered independently because

the pressure unit is centimeters mercury rather than

millimeters mercury.

Table IV. Temperature derivative in millimeters

B.g/°Kjor the 1958 He* Scale. This table gives values

of the first derivative, dP/dT, to four significant

digits. These values are smoother and more precise

than values obtained directly from table I by simple

difference calculation, and they represent true

derivatives of the scale defined by table I. Table V. Auxiliary table jor making hydrostatic

head correction. This table gives, as a function of

pressure, values of the ratio between the density of

liquid He I and the density of mercmy at 0° C.

Table VI. Deviations oj earlier scales jrom the

1958 scale. The definitions of earlier scales used for

obtaining the values in this table are explicith^ given

in explanatory notes which accompanj^ it. Table VII. Auxiliary table jor making corrections

jor the density oj mercury at temperatures other than

4
0° C. This table gives values of the ratio between

the density of mercury at temperatures between 10°

and 39° C and the density at 0° C. Following this

table is an equation useful for making another correction which in precise work must be applied to the

observed height of a mercury column. This equation gives an empirical relation between the acceleration due to gravity and the local latitude and altitude.

If the local value of this acceleration is unknown, the

equation will yield a value sufficiently accurate for

the purpose of manometry.

2. Constants Used in the Computation of

the Scale

Certain constants are necessary for computing a vapor pressure-temperature scale. The values of

these constants adopted for the computation of the

1958 scale are tabulated below. The significance

of the Lq value may be found in Part 1 , Introduction

by F. G. Brickwedde. These constants are: iq = 12.2440 cgs units; io=59.62 j/mole; i?=8.31662

j/mole-deg; density of mercury at 0° 0=13.5951

g/cm^; standard gravity =980.665 cm/sec^; pressure

at the X-point =37.80 mm mercury at 0° C and

standard gravity.

3. Fixed Points on the Scale

The boiling point is at 4.2 1 50° K for P=760.00 mm

mercury at 0° C and standard gravity (or 1013250

dynes/cm^). The X-point is at 2.1720° K for P as noted above. The critical point, if the critical

pressure is taken to be 1718 mm mercury (Kamerlingh Onnes, Leiden Comm. 124b) at 0° C and standard gravity, is at 5.1994° K.

4. Comments on Determining Temperature

by Measuring Vapor Pressure

Two techniques are commonly used for determining a temperature by measuring the vapor

pressure of liquid He*. In one, the pressure at some

point above a bath of liquid helium is measured. In

this case, standard practice has been to add to the

measured pressure, when above the X-point pressure,

an amount equal to the pressure exerted by the

column of helium between the point where the

pressure is measured and the point in the bath

occupied by the object whose temperature is desired.

Below the X-point, no correction of the observed

pressure is ordinarily made, although the pressure

drop in the gas due to pumping may become significant at low pressures. In the other technique, the

pressure over a small amount of helium condensed

in a "vapor pressure bulb" is measured. Since this

"bulb" is normally placed close to the point in the

bath occupied by the object whose temperature is desired, correction of the observed pressure is usually

considered unnecessary above, as well as below, the

X-point. Numerous arrangements have been used

for the pressure-transmitting line from the "bulb"

to the manometer, but no standard practice seems

to prevail. In any such apparatus, thermomolecular

pressure differences between the cold "bulb" and the

warm manometer arise at sufficiently low pressures.

It is generally known that various adaptations of

these two techniques yield slightly different pres- sures and therefore slightly different temperatures,

especially above the X-point. Although these temperatures usually differ by no more than 0.01° K,

special attention to technique seems required when

precision exceeding 0.01° K is desired. Two conditions necessary to any satisfactory technique for

determining the temperature of an object by measuring the vapor pressure of a liquid seem obvious.

First, there must be thermal equilibrium between

the object and the liquid. Second, the pressure at

which the liquid is in equilibrium with its saturated

vapor must somehow be determined. In the case

of He* there is one criterion which, if satisfied,

probably assures that these conditions are met.

Differences between the thermal properties of He*

above and below the X-point are so large that, if the

calibration of a secondary thermometer yields a

continuous curve through the X-point, the technique

b}^ which the calibration was obtained is probably

satisfactory.

Table I. Vapor -pressure of He* (1958 scale) in microns {10~^ mm) mercury at 0° C and standard gravity {980.665 cm/sec^)

0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009

0. 50 0. 016342 0. 016901 0. 017476 0. 018069 0. 018680 0. 019309 0. 019956 0. 020623 0. 021310 0. 022017

.51 . 022745 . 023494 . 024266 . 025068 . 025875 . 026714 . 027578 . 028467 . 029381 . 030321

.52 . 031287 . 032280 . 033301 . 034361 . 035431 . 036541 . 037681 .038852 . 040055 . 041291

.53 . 042561 . 043866 . 045205 . 046581 . 047993 . 049443 . 050932 . 062461 . 054030 . 056640

.54 . 057292 . 058987 . 060727 . 062512 . 064343 . 066221 . 068147 . 070123 . 072149 . 074226

.55 . 076356 . 078640 . 080779 . 083074 . 085426 . 087836 . 090306 . 092837 . 095431 . 098088

.56 . 10081 .10360 .10646 . 10938 .11237 . 11544 . 11858 . 12179 . 12508 .12845

.57 . 13190 . 13543 ism . 14274 .14652 . 15039 . 15,436 . 16840 . 16254 . 16678

.68 . 17112 . 17565 . 18008 . 18471 . 18946 .19430 . 19926 . 20433 . 20951 . 21480

.59 .22021 .22574 . 23139 . 23716 . 24306 .24908 .25524 . 26153 . 26795 . 27461

5
Table I. Vapor pressure of He* {1958 scale) in microns {10~^ mm) mercury at 0° C and standard gravity (980.665 cm/sec^) —Con.

J, Xv nu.uuu (inn 0.001 0.002 0.003 0 004 0 005 nU.UUD nnfi nU.UU/ nn7 n nnfi U.UUo n nnn

u> UU ft oQKnd ft ^ftQd7 n QifiQi u* oioyi n ^94(^n U. 0Z40U n ^^ooK n 9jni

U- 04U1

U- 040ZO

.61 . 35649 .36490 . 37349 . 38225 . 39120 . 40032 . 40963 . 41912 .42881 . 43869 .62 .44877 . 45905 . 46953 . 48023 . 49113 . 50225 . 51358 . 52514 . 53692 . 54894

. Dt> ^(K^ 1

Q

. OuliO . 0/OuD . OODOo . oyyoo fil 9(;r ozouo . ooy /o . DOO/4 . uD/yy . 68250

.64 . 69729 . 71236 . 72771 . 74334 . 75926 . 77548 . 79200 . 80882 . 82595 . 84340

.65 . 86116 . 87925 . 89766 . 91641 . 93550 . 95493 . 97471 . 99484 1.0153 1. 0362 .66 1. 0574 1. 0790 1. 1010 1. 1233 1. 1461 1. 1692 1. 1928 1.2167 1. 2411 1. 2659

• D( 1 001

11. ^IRR olDO 11. 0'tiiy 9490 1. ooy4 1 3964 1 4238 11. 4t;i 4010R 1 4fin9 1. 4oUZ 1. ouyu 1. 0004

DO 1 t;ftQ9 1. ODoJ 1. oyoo 11- ft9Q9 11 Rfin7 . oou

/

1 6925 1 7249 1 7ti7ft 1. (O/O 1 7Q11. /yio 1 RO'^9 1. oZOO 1. ooyo .69 1. 8949 1. 9306 1. 9669 2. 0037 2. 0412 2! 0792 2. 1179 2. 1571 2. 1970 2. 2375

7n • /U O 07Q7 9 QfiOQ oozy 0 4nR1 Z- 4UQ1 2 4499 Z.9 4Q44 4y44 Z- ooyo Z. 0000 0 R91 0 Z- Doiy 2. 6792

.71 2. 7272 2. 7760 2. 8255 2. 8757 2. 9267 2. 9785 3. 0311 3. 0845 3. 1386 3. 1936 .72 3. 2494 3. 3060 3. 3635 3. 4218 3. 4810 3. 5411 3. 6021 3. 6639 3. 7266 3. 7903

• iO O. oD'tv ^ Q9n<i o. y^iu^ 0- yooy 4 n'%44 4 1922 44. 9fi9R ZDZD 4. 004U 44. 4nR4 4UD4 A A'7QQ

.74 4. 6543 4. 6298 4. 7064 4. 7841 4.8629 4. 9428 5. 0238 5. 1059 5. 1891 5. 2735

.75 5. 3591 5. 4459 5. 5338 5. 6230 5. 7134 5. 8050 5. 8978 5. 9919 6. 0873 6. 1840 .76 6. 2820 6. 3813 6. 4819 6. 5839 6. 6872 6. 7919 6. 8980 7. 0055 7. 1144 7.2247

77 7 ^^Rf^ (. OoDO 7 ddOR /. 0D10 71 fiRn7 . uou

/

7 7985 7 9178 0.ft nQRR UOOD R0. 1 Rin lOlU 0 0Q40 0- Zo4y 0- 41U4

7R ft K'i'JR o. OO/O o. DD04 R 70f;Q R0. 09HQ yzoy 9 0627 9 1981 y. oooz 0y. 4741 4/41 Qy. R147 014/ Q 7K71 y. # 0 (

.79 9. 9013 10. 047 10. 195 10. 345 10! 496 10! 650 10. 805 10. 962 11. 121 11. 282

- ou 1 1 44*^ n11. Rin UlU 111.1 777 * / ( 11. 1 1 Q4R yiD 12 117 12. 290 12 465 12 642 10 R99 IZ. OZZ 1 9 009 10. UUO

.81 13. 187 13. 373 13. 661 13. 751 13. 944 14. 138 14. 335 14. 636 14. 737 14. 941 .82 15. 147 15. 356 15. 667 15. 781 15. 997 16. 216 16. 437 16. 661 16. 887 17. 116

. Oi> 17 SilR 17 fiRO 17 ftlQ 1/. oiy 1R nt;s 10. uoo 18 300 1ft 10. 040 '\A^ 1RlO. 709 ixfO 10ly. 049 U40 10ly. OOR zyo 10 Kt^o ly. OOZ

.84 19. 811 20. 073 20.337 20. 605 20. 875 21. 149 21. 426 21. 704 21. 987 22. 272

.85 22. 561 22. 853 23. 148 23. 446 23. 747 24. 052 24. 360 24.671 24. 985 25. 303

.86 25. 624 25. 948 26. 276 26. 608 26. 943 27. 281 27. 623 27. 969 28. 318 28. 671

R7 9Q no7 29 387 29 751 30 119 30. 490 ?n Rfi^ 31 245 31 628 32 014 9o 40 oz. 4U0 R& OZ- oUU 33 199 rto ant) 00. DUZ 34 009 34. 420 34. 835 •JC OKA 00 Z04 35 678 36 106 9fi f?9R 00. 000 .89 36. 974 37'. 415 37. 860 38^ 309 38! 763 39! 221 39. 684 40! 151 40.623 41. 100

. Qnyu 41 p;ri ^11. Ool UD / 49 ^(^7 ^tZ. 00 ( AO nco 40. UOO 43. 553 44 058 44 t;fifl 44, ODO 4t; nfto 40- uoz 4*^ R09 40. OUZ 4R 1 OR 40. IZO

.91 46. 656 47. 191 47. 730 48. 275 48. 825 49. 380 49. 940 50. 505 51. 076 51. 652 .92 52. 234 52. 821 53. 414 54. 012 64. 615 55. 224 55. 839 56. 459 57. 085 57. 717

. wO Oo- OOO 00- tifl QQQ yyy oy. 040 fin "^HQ OU- oUO fin QRd Ql. OoZ Ro "inK oz. ouo RO Ofl4 OZ. yo4 R9 R70 00. 0(U fi4 9ft1 04. ODl

.94 65. 059 65. 763 66. 473 67. 190 67. 913 68. 642 69. 378 70. 120 70. 869 71. 624

.95 72. 386 73. 155 73. 930 74. 713 75. 502 76. 298 77. 101 77. 910 78. 727 79. 551 .96 80. 382 81. 220 82. 066 82. 918 83. 778 84. 645 85. 520 86. 402 87. 291 88. 188

07 oy. RQ noT uyo yu. uuo on 09^^ yu. yzo 01 iiK^ yi. ooo 92 789 93 732 04y4. RRQ ooo Qc^ R40 yO- 04Z QR Rno yo. ouy 07 i;fi4 y / . 004

. QRao OR KfK7 QQ Rf^R yy. Ouo inn f^^T lUU. 00* im f^RK lUl. 000 ino KQi lUZ. Ool 10"^ luo. fin^^ ouo in4 1U4. R9R DOO inFi R70 luo. 0/y 10R 70R lUD. / Zo 107 7ftR .99 108. 853 109. 928 111.012 112. 104 113. 205 114. 315 115. 434 116. 562 117. 699 118. 845

11- onUU 1izu. 9n nnA uuu 191 1Z1> Ifi^ IDu 1izz. 99 ooy 1IZO- 9*1 OZo ^^99 124. 716 lOf; Q1Q 1 97 1 90 izi- izy 1 0R 9t;n izo. oou 190 f^RO izy. oou 1 90 Ron lOU. ozu

1. 01 132. 070 133. 330 134. 600 136. 880 137. 169 138. 468 139. 778 141. 097 142. 427 143. 766

1.02 145. 116 146. 477 147. 848 149. 230 160. 622 152. 025 153. 438 154. 862 156. 297 157. 742

1 1 f^Q 1 QR loy. lyo lAA f\(KR IfiO 14f^ lOZ- 140 IDO. 004 luo. 100 1 fifi fi47 100. 04 J 1 RR 1 7n lOo. 1/U 1R0 704 loy. /U4 171 OKCX 111. zou 170 1 (Z. RnR ouo

1.04 174. 375 175. 956 177. 548 179. 152 180. 768 182. 395 184. 035 185. 686 187. 349 189. 024

1. 05 190. 711 192. 412 194. 124 195. 849 197. 587 199. 336 201.098 202. 874 204. 661 206. 461 1.06 208. 274 210. 101 211. 941 213. 794 215. 660 217. 538 219. 431 221. 335 223. 255 225. 187

1 n7 907 no 990 nQ9 z^y. uyz O^il (\(KK £>OL. UDO 99Q nf;o ZoO. uoz

OQC (\C\Q LOO. UOO UDO 99Q zoy, noR uyo 041 190 Z41. lOo 949 IQ1; Z40. lyo OAK. Z40. ORK ZDO

1. uo OA'7 Q';n 940 df^Ct Zty. ^ou ZOl. ODD OK'i fiQ4 ZOO. oy4 zoo. OOo 0';7 QQt; zo/ . yyo ORn 1 RR zou. IDo ORO 9(^f; ZDZ. 000 OR4 C^KT Z04. 00/ ORR 77/1 ZDO. / / 4 1.09 269. 006 271. 254 273. 516 275. 794 278. 087 280. 396 282. 719 285. 058 287. 413 289. 783

1 in 9QO 1 fiO zvz- loy 9Q4. (^79 OQfi QQ1 zyu. yyi OQQ 40fi zyy. 4Z0 301 877 *^n4 0U4. 944 044 QnR ROS OUD. oZO 900 907 ouy. oz( Oil. 91 1 040 R49 914 97t; 014. 0/0

1. 11 316. 923 319. 489 322. 072 324. 671 327. 287 329. 920 332. 570 335. 237 337. 921 340. 622

1. 12 343. 341 346. 079 348. 834 351. 606 354. 397 357. 205 360. 030 362 874 365. 735 368. 614

1. 10 •^71 t^lO 0/ 1. OU oit. fizy •^77 "XRA oil - 004 •^ftn viR oou. Olo ooo. zyu OOO- oRn zou 9R0 oon ooy. zyu 9QO 917 oyz. 01 4 90 9R4 oyo. 004 900 AO(\ oyo- 40U

1. 14 401. 514 404. 619 407. 744 410. 887 414. 050 417. 232 420. 434 423. 655 426. 896 430. 156

1. 15 433. 437 436. 739 440. 060 443. 402 446. 764 450. 146 453. 549 456. 972 460. 416 463.880

1. 16 467. 365 470. 873 474. 402 477. 951 481. 522 485. 114 488. 728 492. 363 496. 019 499. 697

1 17 ouo. oyo c;n7 1 1

OU<- llo i;in rr9 oiu. 000 KTA ftQn 014. DoU OlO. t^lR 41410fl {\90 OOQ ozz. zzy f;oR nRo OZD. UDZ KOQ 01

ozy. yi / f;99 704 000- /y4 t;97 RQ4 00 / . Dy4

1 1

Q

KA.1 fil 7 olO- OOt '140 K'li^ 04y. 000 000. Ozo 557 544 ODl. 000 ODO. D40 c;RO 791 ooy. (01 0/0. f;79 QAf\ 04U 0K771 1 . 070 V 1 Z

1. 19 582. 129 586. 310 590. 515 594. 744 598! 998 603. 275 607. 576 611. 901 616. 251 620. 626

1 on 000. yui AQQ Q77 OOo. 0/ i fi40 S77 04Z. Ot i R47 An'i 04/. 4U0 001. yo4 000. oou RRl 191 DDI, 101 RRt; 7t;R 000. / 00

1.21 670. 411 675. 091 679. 797 684. 529 689. 287 694. 071 698. 881 703. 717 708. 580 713. 470

1.22 718. 386 723. 331 728. 303 733. 301 738. 327 743. 380 748. 461 753. 569 758. 704 763. 866

1. zo toy, uo/ 77*1 077 77Q fioc; 7(14 flm jo^. isui 7Qn ihf; /yu. luo 70e: At"? IvO. 40 / flnn 7Q0 oUU. iMo Qnfi 1 G7 OUD. Lot oil. DUO R17 r\KO 01 /. uoz

1. 24 822. 527 828. 033 833. 569 839. 135 844. 730 850. 353 856. 006 861. 689 867. 402 873. 144

1. 25 878. 916 884. 720 890. 555 896. 420 902. 315 908. 241 914. 197 920. 184 926. 202 932. 250

1. 26 938. 330 944. 442 950. 585 956. 759 962. 965 969. 203 975. 473 981. 774 988. 107 994. 472

1.27 1000. 87 1007. 30 1013. 77 1020. 27 1026. 80 1033. 36 1039. 95 1046. 58 1053. 24 1059. 94

1.28 1066. 67 1073. 44 1080. 24 1087. 07 1093. 93 1100. 83 1107. 77 1114. 74 1121. 74 1128.78 1.29 1135.85 1142. 96 1150. 10 1157.28 1164. 49 1171. 74 1179. 02 1186. 34 1193. 69 1201. 08

6
Table I. Vapor pressure of He* (1958 scale) in micron {10 ' mm) mercury at 0° C and standard gravity {980.665 cmjsec^) —Con.

0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009

1908 '^^ 191=i QS 1 99^ 4S 1931 09 1 93R 1 946 90 19'i'^ ft"! 1261. 54

. _

196Q 96 1277 02

1.31 1284. 81 1292. 64 1300. 51 1308. 42 1316. 37 1324. 35 1332. 37 1340. 43 1348. 53 1356. 66

1. 32 1364. 83 1373. 04 I^QI iOOi. OUQfl XOOiJ. Ott 1400 9q 1414. 70 1423. 15 1431. 64 1440. 16

1. 33 1448. 73 1457. 34 14fi^ QQ 1474. 67 1483. 40 1492. 17 1XOUU. 'iOn q73 1 1 'iOQ 89 1518. 71 1527. 64

1.34 1536. 61 1545. 62 1554. 68 1563. 78 1572. 91 1582. 09 1691. 31 1600. 57 1609. 88 1619. 23

1.35 1628. 62 1638. 06 1647. 54 1657. 06 1666. 62 1676. 23 1685. 88 1695. 57 1705. 31 1715. 09

1.36 1724. 91 1734. 78 1744. 69 1754. 65 1764. 65 1774. 69 1784. 78 1794. 91 1805. 09 1815.31

1. 37 iQQr on lOOU. i)yJ 1 R4fi 96 iouU. DO 1867. 11 1877. 61 1

1000. lU 1898. 75 iqoq XoUf. 009S ±tfAi\J. 1 090 00uu L38 1930. 79 1941. 57 1952. 39 1963. 26 1974" 18 1985- 14 1996. 15 2007. 21 2018. 32 2029. 47

1.39 2040. 67 2051. 92 2063. 22 2074. 57 2085. 96 2097. 40 2108. 89 2120. 43 2132. 02 2143. 66

1. 40 91 R7 flQ 917ft Rft All. 1 o- oo 91^i.i^U. QO 791 Ai 9909 fil 2214. 54 9990 r.r> A.AiAi\i- 00 9938 A,^OKJt Of57 99(^0 fifi J^Al\jAf 9909 80OU

1.41 2274. 99 2287. 23 2299. 52 2311.87 2324. 27 2336. 72 2349. 22 2361.77 2374. 37 2387. 02

1 42 2412. 49 £i~t£iO' OU 2438. 17 94*^1 ^rtOx. OQUi? 2464 06 2477. 09 2490. 1

^OUO. OU 9'ilfi 48

1. 43 2529. 72 ^OiJU- OU zoua. 9^fiQ 7(\ / o

9c;eQ 91 9^qfi 79 9fiin 90 9093 qi 9037 ^uo 1 . 00^9, 9fi'i1 ZiUox. ox^1

1.44 2665. 09 2678. 93 2692. 82 2706. 77 2720. 78 2734. 84 2748. 96 2763. 13 2777. 36 2791. 65

1.45 2805. 99 2820. 39 2834. 85 2849. 37 2863. 95 2878. 58 2893. 27 2908. 02 2922. 82 2937. 68

1.46 2952. 60 2967. 58 2982. 62 2997. 72 3012. 88 3028. 09 3043. 36 3058. 69 3074. 08 3089. 53

1 47 3105 04 ^190 61 ^136 94 3151. 94 3167. 69 3183 0100. iJU ^0 3199 37 0^1 391 0.^ 30OU 3931 0^0X. OU3ft 3947 tjA/^ t * OU36

l! 48 3263. 48 3279. 66 3295. 90 3312. 20 3328! 57 3345. 00 3361.49 3378. 04 3394. 65 3411.33

1.49 3428. 07 3444. 87 3461. 74 3478. 67 3495. 66 3512. 72 3529. 84 3547. 03 3564. 28 3581. 59

1. 50 3598. 97 3616. 41 3633 Q2 Sfi'il 49 3669 13 ouou. ^fiftfi ft^ 00 Ol^704U^. fin UU 3722. 43 03740 ( TtU. 3300 37.58 0 1 00* 294dU

1.51 3776. 32 3794. 42 3812. 59 3830. 82 3849. 12 3867. 49 3885. 92 3904. 42 3922. 99 3941. 62

1. 52 3960. 32 9Q7Q no 3997. 93 401 rruxu.fi OO 403*1 ^UOO. 80OU 4054. 84 407^ ^Ul 0. q^i !70 4093. 12 4112. 37 4131. 69

1. 53 4151. 07 4170. 52 4190 05 490Q fi'i 492q ^9 ^£i'X-J. UU 49fift S7 4288. 74 4308 ^OUO. 68UO 4328 70

1. 54 4348. 79 4368. 95 4389. 17 4409. 47 4429. 84 4450. 28 4470. 80 4491. 39 4512. 05 4532. 78

1. 55 4553. 58 4574. 46 4595. 41 4616. 44 4637. 54 4668. 71 4679. 96 4701. 28 4722. 67 4744. 14

1. 56 4765. 68 4787. 29 4808. 98 4830. 74 4862. 58 4874. 49 4896. 48 4918. 54 4940. 68 4962. 89

1. 57 4985. 18 5007. 54 5029. 98 5052 50 ,')075 OU 1 o- 09u u 50Q7 OUi7 f . 76MJ 5120. 51 5143. 33 5166. 23 5189. 21

1. 58 5212. 26 5235.' 39 5258! 60 528l! 89 5305. 26 5328. 71 5352! 23 5375! 83 5399! 61 5423. 27

1. 59 5447. 11 5471. 03 5495. 02 5519. 10 5543. 26 5567. 49 6691. 81 5616. 21 5640. 68 6665. 24

1. 60 5689. 88 5714. 60 6739. 40 5764 O 1 28A/\J 6789 0 2') 1 OiJ. if

UOXt. ^1814 OU30 5839 49 5864. 63 5889. 92 5915. 30

1.61 5940. 76 5966. 30 6991. 92 6017. 62 6043. 41 6069. 28 6095. 24 6121. 28 6147. 40 6173. 61 1.62 6199. 90 6226 27 62.^12 72 VtAdi t7. A/\f uouo. 00 fiQQ9 cq fi'^^q "^q 6386 UOO*.'- 27A^ 1 6413 U^XO- 23AiKJ 6440. 28

1. 63 6467. 42 6494. 64 6521. 95 6549 uu^j. 35OO 6576 UO 1 u- 840^ 6604. 41 6632. 07 6659. 81 6687. 64 6715. 56

1.64 6743. 67 6771. 66 6799. 84 6828. 11 6856. 47 6884. 91 6913. 44 6942. 07 6970. 78 6999. 58

1.65 7028. 47 7057. 45 7086. 52 7115. 67 7144. 92 7174. 26 7203. 69 7233. 21 7262. 82 7292. 52

1.66 7322. 31 7352. 19 7382. 15 7412. 21 7442. 36 7472. 60 7502. 94 7633. 37 7563. 89 7594. 60

1.67 7625. 21 7656. 01 7686 1 uou» 90o\i 7717. 88 7748. 96 7780. 13 7811. 40 7842. 76 7874. 21 7906. 76

1.68 7937. 40 7969! 13 8000. 96 8032! 88 8064! 90 8097^ 01 8I29! 22 8I61! 53 8I93! 93 8226! 43

1. 69 8259. 02 8291. 70 8324. 48 8357. 36 8390. 33 8423. 40 8456. 57 8489. 84 8523. 20 8556. 66

1. 70 8590. 22 8623 87 8657 OUU f • 62\JAi 8691. 47 8725 0 I ^0. 42 8759. 47 8793 0 ( >70. 69 8827 OOAji . 86OU 8862. 20 8896. 64

1. 71 8931. 18 8965. 82 9000. 5fi 9035. 40 9070. 33 9105. 36 9140. 50 9175. 74 9211.08 9246. 62

1. 72 9282. 06 9317. 70 Q49'^ 99 q4fi1 9fi 9497. 41 9*^33 66 9570 CTO * u. 01ux 9606 46

1. 73 9643. 02 9679 68 9716. 45 u

oo. o^ 9790 2q qft97 ^fi qftfi4 ^4 9901. 82 9939. 21 9976. 70

1.74 10014. 3 10052. 0 10089.

10127. 7 10165. 7 10203.

10242. 0 10280.

10318.10367. 3

1. 75 10395.

10434. 6 10473.10512. 4 10561. 5 10590. 7 10630. 0 10669. 4 10708.10748. 5

1. 76 10788.

10828. 0 10867.10907.

10948. 0 10988.11028.

11069. 2 11109. 7 11150.

1. 77 11191. 2 11232.

11273.11314. 2 11355.

11396.11438.

11479. 7 11521. 4 11563.

1.78 11605.

11647]11689!

1173L4 11773!11816!11858!1190l! 4 11944! 2 11987! 1 1.79 12030.

12073. 2 12116. 4 12159. 7 12203.

12246. 6 12290. 3 12334.

12378. 0 12422.0

1.80 12466.

12510 3 12554. 7 12.'i9Q 2 12643 x^u^o. 8

19688 X ^uoo. 512733 3 12778. 2 12823. 2 12868.

1.81 12913.

12959.

13004. 6 13050. 2 13095. 9 13141.8 13187.8 13233.13280.

13326.

1.82 13372.

13419.

13466.13612. 8 1.35,59 XOOOi?. 7i xouuu. 1 l^fi*!^ xouoo. S0 13701.13748.13796. 0

1.83 13843.

13891. 3 13939 1 13987.

14083. 4 14131. 7 14180.14228.

14277. 3

1.84 14326.

14375.14424.

14473. 2 14622. 5 14571.14621. 4 14671. 0 14720.

14770.

1. 85 14820. 7 14870.

14921. 0 14971.15021.15072. 5 15123.16174. 0 15225. 0 16276.

1.86 15327. 3 15378.

16430.15481.

15533.15585. 2 15637. 2 15689. 3 15741. 5 15793.

1. 87 15846.

16898.

15951 6 16004. 4 16057 xuuo 1.03 16110.

Ifilfi^ xuxuo. fiu 16916 9 16270. 4 16394 0

1.88 16377.

1643l! 5 16485. 5 16539!

16593.

16648." 1 16702. 6 16757. 2 I68I1! 9 16866. 7 1.89 16921.

16976.

17032. 0 17087. 3 17142. 8 17198.

17254.17309. 9 17365. 9 17422. 0

1. 90 17478. 2 17534.

17591.17647. 7 17704. 5 17761. 4 17818. 4 17875.

17Q39 8 17qqo X ( UO\}, 9Ai

1. 91 18047. 7 18105. 4 18163.

18221. 1 18279. 1 18337. 3 18395.

18454.

18512. 6 18671. 3

1. 92 18630.

18689 0 18748. 1 18807 3 18866 7 1Rq9fi 9 Iftqft^ xoyoo. ft0 xou^o. 0 19106. 4 19165 4

1.93 19225. 5 19285.

19346. 2 19406. 7 19467. 4 X ^00«7. X iqO'SO XIJUOU. 1X 19711. 3 19772. 6

1.94 19834.

19895.

19957. 4 20019. 2 20081. 2 20143. 3 20205.

20268. 0 20330. 5 20393.

1. 95 20455. 9 20518.

20681. 9 20645.

20708. 4 20771. 8 20836.

20899.20963. 0 21027. 0

1. 96 21091. 1 21155. 4 21219.

21284. 3 21348.

21413.21478.21643. 7 21608.21674. 2

1.97 21739. 7 21805. 3 21871.

21937. 0 22003. 0 22069. 2 22135. 6 22201. 9 22268. 5 22335. 2 1.98 22402. 0 22469. 0 22536. 1 22603. 3 22670. 7 22738. 2 22805. 9 22873. 7 22941. 6 23009. 7

1. 99 23077. 9 23146. 2 23214. 7 23283.3 23362.

23421. 0 23490.0 23659.

23628.4 23697.

545667—60 2 7
Table I. Vapor pressure of He* (1958 scale) in microns {10~^ mm) mercury at 0° C and standard gravity (980.665 cm/sec^) —Con.

0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009

UU 007C7 4 9^0^17 1 ZOoO/. X 95Qn7 n zoyu* . u

Q5077 0 94047 9 Zll 1 ( , 0 _—. ,

Z^ZOo. 4 94590 1 z^ozy. X O4OQQ Q

2.01 24470.9 24542.24613.

24684.24756.1 24827. 8 24899. 6 24971. 5 25043.

25115.8

2 02 ZD loo. X ZuZOU. D 9R40R 0 9R47C Q ZO'i/O. y

Officii 0 ZDOoi. yoc^Roc; 1 ZODZO. X 9'i771 zu/ 0 / X. y

9RQ4.R K Z004U. 0

9(^010 9 zoyyo. 1 ZOUD/. X 9R141 5 9R91 K fi ZOZXO. D zozyu. u

9R5R,< A 9A450 5 ZD0X*1. X

2.04 26664. 2 26739. 5 26814. 9 26890. 5 26966. 2 27042. 0 27118. 0 27194.

27270. 4 27346.

2. 05 27423.

27500.27576.

27653. 8 27730.27808. 1 27885. 4 27962. 9 28040.

28118.4

2.06 28196. 3 28274. 4 28352.

28430.9 28509. 4 28588.

28666. 8 28745. 7 28824.7 28903.

2 07 9SQfiQ 9 901 49 5 00909 1 0Q509 0 zyouz. u 905Q9 0 zyooz. u

OQ/1RO 9 zy^oz. z zyo^z. 09Qfi99 zyozz. 0y 9070^

2.' 08 29784. 2 29865.

29946.30027. 2 30108. 5 30189.

30271. 5 30353. 2 30435. 0 30517.

2.09 30599.30681.30763. 8 30846. 4 30929.

31011.9 31094. 9 31178.

31261. 2 31344.

2 10 31428 1 ^1oxoix. 1^1 1 ft0

51oioyo. tiQt; fiD51fi70 ft 517ft5 7 51ft/17 Q 51059 5 oiyoz. 0 59A1A ft ijZUXD. 0 32101 4

501 CA 9

2.11 32271.

32356.32441.4 32526.

32612. 3 32697. 9 32783. 6 32869. 5 32955. 5 33041.

2 12 QQIOQ n •^^91 4 ^ OOZl^r. 0 OOoUl. 55501 1X 555ft7 ft 0000/. 0 55474 fi 55c;ri r OoODX. D

55ft;1ft 7 5575R 0 00/ OU. U Q5Q95 A 2 13 Ooyyo. D ^4nSR 4 54174 O^X 4 / 1. 1

5i9fi9 c; 5;15';A 7 QAAIQ 0 5/1 1^07 ^ 54R1fi 1 34704 9 0% i >70. 0

2. 14 34882.

34971. 9 35061. 2 35150. 6 35240.

35329. 9 3.5419. 7 35509. 7 35599. 8 35690.

2. 15 35780.

35870.35961. 3 36052. 0 36142.

36233.36325. 0 36416. 3 36507. 7 36599.

2. 16 36690.

36782. 7 36874.36966. 6 37058.

37151.37243. 5 37336. 0 37428.

37521.

2 17 37614 3 57707 4 57flnn fi O/oUU. D

57ft05 Q 57QQ7 5 OQOQO ft 00 X/ 4. ^ OoZDo. 5ft9fift 1X QQ5A9 n

2! 18 38550'. 2 38644. 5 38739. 0 38833. 6 38928. 4 39023. 3 39118. 4 39213. 6 39309. 0 39404.

2. 19 39500.

39596. 2 39692. 2 39788.39884. 6 39981. 0 40077.

40174.40271. 3 40368.

2 20 4U'tOO. 0 4U0DO. u

4nfifin K 407*^0 9 /lOQf^fi 0 WOOD. U

A1C\t^O 9 1XU0Z, Z

4141X0U. 1 f;A RD 41249.

41347.

2. 21 41446. 6 41545. 6 41644. 7 41744.

41843. 4 41943. 0 42042. 8 42142. 7 42242. 8 42343.

2 22 42443 5 'tiO^^, X 49fi44 ft d074Ei 7 AOftAfi ft AOQAQ A 451 ^0 Q 459t;9 A 433.54 5

2. 23 45fif;Q 7 "KjDDX. u

d57ft5 45ftftfi 9 400DD. Z /150fi0 0 dAA79 0 44175 2 44278 5 44382 0

2.24 44485. 7 44589. 5 44693. 5 44797.

44901. 9 45006. 4 45111.0 45215. 8 45320. 8 45426.

2. 25 45531.

45636.45742. 4 45848. 2 45954.

46060. 2 46166. 5 46273. 0 46379.

46486. 5

2. 26 46593.

46700.46807. 9 46915. 4 47023. 0 47130.

47238. 8 47347. 0 47455.

47563. 8

2 27 47672 5 d7ftQfl 5 il7QQO K 4/yyy. o

/I ft 1 Aft 0 /iOOlft A AQ'iOQ 1 ^PSoZeS. X 486.58 2 2^28 48768'. 6 48879. 2 48989.

49100.49211.

49323.

49434. 4 49546.

49657.

49769. 7 2.29 49881. 8 49994.

50106. 5 50219.50331.

50444.50558.

50671. 3 50784. 8 50898. 5

2 30 OIUJ-Z. 0

f;i 1 9A 5 1 940 f;i5(^4 ft i;i4fiQ 5 K^ KQA A uiOOl. UC^IROQ 0 oioyo.

y

51814 0

f;iqoQ 9 52044. 6

2.31 52160. 2 52276. 0 52391. 9 52508. 0 52624. 3 52740.

52857. 4 52974. 2 53091. 2 53208. 4

2. 32 oOoZu. 0

c;5445 5 OoODX. f^5^Kl AU

t;5ft7ft Q K57Q7 0 t;501 K 5 f;dA55 7 Kill KO 5 Otl OZ.

54271.

54390.

2. 33 tl4fi9Q O^lDZo. 0

f;474ft A fi40Q7 ft p;{iiA7 ft OOiU/ . D1^997 ft OOZZ/. 0

C,K540 9 OOolto- ^ uu^uo. 0 55589.

2. 34 55710. 5 55831.

55952. 9 56074.56196.

56318.56440.

56562.

56684.

56807. 2

2. 35 56930.

57053.

57176.

57299.57422.57646.57670. 5 57794. 6 57918.

58043.

2. 36 58167.

58292. 6 58417.5 58542. 6 58668. 0 58793.58919. 2 59045. 0 59171.

59297. 4

2. 37 CQ4OO Q oyoou.

t;0R77 5 oyo 1 ( . 0

£;QQ51 K oyyoi. 0 DUXcSD. 0 DUO 14. 0 60449 UU44i. 0? 60570. 5

2! 38 60698.

60827.

60955. 9 61084. 7 61213.

61343.

61472. 5 61602.

61731. 9 6I861]

2. 39 61992. 0 62122. 4 62253. 0 62383. 7 62514. 6 62645. 8 62777.62908.

63040. 3 63172. 2

2. 40 U0oU4. 0 RQ'^fiQ A Doooy. U

fi57A1 ft R505/1 4 ftQQR7 4 ft4100 D41UU.

64233 9 R45R7 r; 64501. 2

2. 41 64635.

64769.

64903. 7 65038. 2 65173.

65307. 9 65443. 0 65578. 3 65713.

65849.

2 42 Rf^OQf^ 4 DOyoO. 1 onizx. 0 DDiiO/. / CO con ft «Rftft7 7 DODO*. / ARQA/f 7 fiR041 unyii. Qy 67079 4 67217. 0

2 43 D/O04. 0

R7/<QO Q D/4yz. 0fi7R51 0 D/DoX.fi77fiQ A R7QA7 Q D/yu/. y ADAll R 7 fiftlQC; 7 fift594 ft AQ4A4 9 6860^ 7

2.44 68743.

68883.

69023. 6 69164.

69304.69445. 3 69586.

69727.

69868. 7 70010. 3

2. 45 70152. 0 70294.

70436.70578.

70721. 0 70863. 7 71006.

71149. 7 71293.

71436.

2.46 71580.

71724.71868. 2 72012.

72157. 0 72301. 6 72446.5 72591.

72736.

72882. 4

2. 47 70000 1 751 74 n 75590 /oOZU. 1X 754ftR A /O'iOD. 75fi19 ft

/ 00 iZ. 0 /o/ oy. 0

750Aft 4 740Kq c

/ 'i'UOo. 0 74900 8 74348. 3

2. 48 74496. 0 74643. 9 74792. 0 74940.

75088.75237. 6 75386.

75535. 6 75685. 0 75834! 5 2.49 75984. 2 76134. 2 76284. 3 76434. 7 76585.

76736.

76887.

77038. 3 77189. 7 77341. 3

9 'in 77405 1 77fi/t 1 / (OlO. X 777Q7 5 770.^0 7 /olUz. 6 foZOO. L 7Q,i0fi 1 loWo. X

7ft'\fi1 5 78714. 7 78868 4

2. 51 79022. 2 79176. 3 79330.

79485. 0 79639. 7 79794. 6 79949. 7 80105. 0 80260.

80416. 3 2 52 fin 1^79 9 Crt70fl 5 QAfiQ4 7 filOAl 9 QIIOQ A oxxys. u sxoo^. y OlOiZ. X 81827.

81984.

2 53 (391 49 0 (109m 1 ftOJPiO ft QOftlft 9 oZDlo. Z oZ/ / / . X ozyou. X 41500^^ 4 oouyo. 83254 9 83414. 6 83574. 5

2.54 83734.

83894.

84055. 4 84216. 2 84377.

84538.

84699. 6 84861. 2 85023. 0 85185.

2. 55 85347.

85509. 6 85672. 3 85835. 2 85998. 2 86161. 5 86325. 0 86488.

86652. 7 86816.

2. 56 86981. 2 87145. 8 87310.

87475.87640.87806. 3 87971.

88137. 8 88303.

88470.

QQAQA 7 QCfiOQ 4 OOoUO. 1ftfiQ7A 4 C01 57 ft Q05A4 Q 00/179 fi0A40 5 QQftOft 4 SQQ76 7 90145.

2.58 90313.90482.

90651.

90821. 2 90990.91160. 5 91330. 5 91500. 7 91671.

91841.8

2.59 92012.92183.92355. 0 92526.

92698. 3 92870. 3 93042. 5 93214. 9 93387. 5 93560.

^. DU yo/ 00. 4

OQonft 7 yoyUu. / OHOQA 9 u'lUoU. Z y'izoo, yCIA A 07 Q OHRAO A 0/177A 5 yi/ /D. 0

040^^0 y-iyou. Qy 95125. 7 95300 8

2. 61 95476.

95651. 5 95827. 2 96003.96179. 3 96355.

96532. 2 96709. 0 96886.

97063. 3

2. 62 (170,1 A Q 97418. 5 y/OwD. 0

0777/) 7 n70(^Q 1 y/yoo. 1 OQ51A R OQ/lftO ft Q884R 5

z. bo nOQQQ A yyooo. 1 yyouo.

007/10 /) yy/4y. 4OOOQO Q yyyou.10A1 1

XUUIX i

1xuuzyo A09Q5 100474 100656

2. 64 100838 101020 101202 101385 101568 101751 101934 102117 102301 102485

2. 65 102669 102854 103038 103223 103409 103594 103780 103966 104152 104338

2. 66 104525 104712 104899 105086 105273 105461 105649 105837 106026 106214

2. 67 106403 106592 106781 106971 107161 107351 107541 107731 107922 108113

2.68 108304 108495 108687 108879 109071 109263 109456 109648 109841 110035

2. 69 110228 110422 110616 110810 111004 111199 111393 111588 111784 1 111979

8
Table .1 Vapor pressure of He* (1958 scale) in microns {10~^ mm) mercury at 0° C and standard gravity (980.665 cm/sec^) —Con.

0.000 0.001 0.002 0.003 0.004 0.005 . 0.006 0.007 0.008 0.009

2. 70 112175 112371 112567 112764 112960

. ._

113157 113354 113552 113749 113947

2.71 114145 114343 114542 114741 114940 115139 115339 115538 115738 115939

2. 72 116139 116340 116541 116742 116943 117145 117346 117648 117751 117953

2. 73 118156 118359 118562 118766 118970 119174 119378 119683 119788 119993

2.74 120198 120403 120609 120815 121021 121228 121434 121641 121848 122065

2. 75 122263 122471 122679 122887 123096 123305 123514 123723 123933 124143

2. 76 124353 124563 124773 124984 125195 125406 125617 125829 126041 126253

2. 77 126465 126678 126891 127104 127317 127531 127745 127959 128173 128388

2.78 128603 128818 129033 129249 129465 129681 129897 130114 130331 130548

2. 79 130765 130983 131200 131419 131637 131855 132074 132293 132613 132732

2. 80 132952 133172 133392 133613 133834 134055 134276 134498 134720 134942

2. 81 135164 135387 135609 135832 136056 136279 136503 136727 136952 1.37176

2. 82 137401 137626 137851 138077 138303 138529 138755 138982 139209 139436

2. 83 139663 139890 140118 140346 140574 140803 141032 141261 141490 141719

2. 84 141949 142179 142409 142640 142870 143101 143333 143564 143796 144028

2.85 144260 144493 144725 144958 145192 145425 145659 145893 146128 146362

2. 86 146597 146832 147068 147304 147540 147776 148012 148249 148486 148723

2. 87 148961 149199 149437 149675 149913 150152 150391 150630 150869 151109

2. 88 151349 151589 151830 152070 152312 152553 152794 153036 163278 153520

2. 89 153763 154006 154249 154493 154736 154980 155224 155469 165714 156969

2. 90 156204 156450 156695 156941 157188 157434 157681 157928 158176 158423

2. 91 158671 158919 159168 159416 159665 159914 160164 160413 160663 160914 2.92 161164 161415 161666 161917 162169 162421 162673 162925 163178 163431

2. 93 163684 163937 164191 164445 164699 164954 165208 165463 165719 165974

2.94 166230 166486 166742 166999 167256 167513 167770 168028 168286 168544

2.95 168S02 169061 169320 169579 169839 170099 170359 170619 170880 171141

2. 96 171402 171663 171925 172187 172449 172712 172974 173237 173501 173764

2. 97 174028 174292 174557 174821 175086 175352 175617 175883 176149 176415

2.98 176682 176949 177216 177484 1777.52 178020 178288 178557 178825 179095

2. 99 179364 179634 179904 180174 180444 180715 180986 181257 181629 181801

3. 00 182073 182345 . 182618 182891 183164 183438 183712 183986 184260 184536

3.01 184810 185085 185361 185636 185912 186189 186465 186742 187019 187296

3. 02 187574 187852 188130 188409 188687 188967 189246 189626 18980.'^ 190086

3. 03 190366 190647 190928 191209 191491 191773 192055 192338 19262i 192904

3. 04 193187 193471 193755 194039 194324 194608 194894 196179 195465 195751

3. 05 195037 196323 196610 196897 197184 197472 197760 198048 198336 198625

3. 06 198914 199203 199492 199783 200073 200363 200654 200945 201237 201628

3. 07 201820 202112 202405 202697 202991 203284 203578 203871 204166 204460

3. 08 204755 205050 205346 205641 205937 206233 206530 206827 207124 207421

3. 09 207719 208017 208315 208614 208912 209221 209511 209810 210110 210411

3. 10 210711 211012 211313 211614 211916 212218 212520 212823 213125 213429

3. 11 213732 214036 214340 214644 214949 215254 215559 215866 216171 216477

3. 12 216783 217090 217397 217704 218012 218320 218628 218937 219246 219565

3. 13 219864 220174 220484 220794 221105 221416 221727 222039 222360 222663

3. 14 222975 223288 223601 223914 224227 224541 224855 225170 226485 225800

3.15 226115 226431 226747 227063 227379 227696 228013 228331 228649 228967

3. 16 229285 229604 229922 230242 230561 230881 231201 231521 231842 232163

3. 17 232484 232806 233128 233450 233772 234095 234418 234742 235066 235390

3. 18 235714 236039 236364 236689 237014 237340 237666 237993 238320 238647

3. 19 238974 239302 239630 239958 240287 240616 240946 241275 241605 241935

3. 20 242266 242597 242928 243259 243591 243923 244255 244588 244920 245254

3. 21 245587 245920 246255 246589 246924 247259 247595 247930 248266 248602

3. 22 248939 249276 249613 249951 250289 250627 250965 251304 251643 251982

3. 23 252322 252662 253002 253343 253684 254025 254367 254709 255051 265393

3. 24 255736 256079 256423 256767 257111 257455 257800 258145 258490 258836

3. 25 259182 259528 259875 260222 260569 260916 261264 261612 261960 262309

3. 26 262658 263007 263357 263707 264057 264408 264759 265110 265462 265814

3. 27 266166 266519 266871 267225 267578 267932 268286 268641 268995 269351

3.28 269706 270062 270418 270774 271131 271488 271845 272203 272661 272919

3. 29 273278 273637 273996 274355 274715 275075 275435 275796 276157 276618

3.30 276880 277242 277605 277967 278331 278694 279058 279422 279786 280151

3. 31 280516 280881 281247 281613 281979 282346 282712 283080 283447 283815

3. 32 284183 284552 284920 285290 285659 286029 286399 286770 287140 287612

3. 33 287883 288256 288627 288999 289372 289745 290118 290492 290866 291240

3. 34 291615 291990 292365 292741 293117 293493 293870 294247 294624 295002

3. 35 295380 295758 296137 296516 296895 297275 297655 298035 298416 298797

3. 36 299178 299560 299941 300324 300706 301089 301472 301856 302239 302624

3.37 303008 303393 303778 304163 304549 304935 305322 305709 306096 306483

3. 38 306871 307259 307648 308037 308426 308815 309205 309595 309986 310377

3.39 310768 311159 311551 311943 312335 312728 313121 313515 313908 314302

9
Table I. Vapor pressure of He^ (1958 scale) in microns [ICr^ mm) mercury at 0° C and standard gravity (980.665 cm/sec^) —Con.

0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009

3.40 314697 315092 316487 315882 316278 316674 317070 317467 317864 318261

3. 41 01318659 D/* m 319057 319455 319854 320253 320652 321052 321452 321852 322263

3. 42 322654 323065 323457 323869 324262 324665 325068 325471 325876 326279

3.43 326684 327089 327493 327899 328305 328711 329118 329625 329932 330339

3. 44 330747 331155 331564 331973 332382 332792 333202 333612 334023 334434

3. 45 334846 335257 335668 336081 336493 336906 337319 337733 338147 338661

3. 46 338976 339391 339806 340222 340638 341054 341471 341888 342305 342723

3.47 343141 343659 343978 344397 344817 345237 345657 346077 346498 346919

3.48 347341 347763 348185 348608 349030 349454 349877 350301 350725 351150

3.49 351575 352000 352426 352852 363278 353705 354132 354560 354987 355416

3. 50 365844 356273 366702 357131 357561 357991 358422 358852 359284 359715

3. 51 360147 360579 361012 361445 361878 362312 362746 363180 363615 364050

3. 52 364485 364921 366367 366794 366231 366668 367106 367544 367982 368421

3. 53 368860 369299 369739 370179 370619 371060 371501 371943 372384 372826

3. 54 373269 373712 374155 374599 375043 375487 375932 376377 376822 377268

3. 56 377714 378160 378607 379064 379502 379950 380398 380846 381295 381744

3. 56 382194 382644 383094 383546 383996 384447 384899 385361 385804 386257

3.57 386710 387164 387617 388072 388526 388982 389437 389893 390349 390805 3.68 391262 391719 392177 392634 393092 393651 394010 394469 394929 395389

3. 59 395849 396310 396770 397232 397693 398155 398618 399081 399544 400007

3. 60 400471 400935 401400 401865 402330 402796 403262 403728 404195 404662

3. 61 405130 405698 406066 406535 407004 407473 407943 408413 408883 409354

3, 62 409825 410296 410768 411240 411713 412186 412659 413133 413607 414081

3. 63 414556 415031 415507 415983 416459 416936 417412 417890 418367 418846

3. 64 419324 419803 420282 420761 421241 421721 422202 422683 423164 423646

3.65 424128 424610 425093 425576 426060 426643 427028 427512 427997 428482

3. 66 428968 429454 429941 430427 430915 431402 431890 432379 432867 433356

3. 67 433846 434336 434826 435316 435807 436298 436790 437282 437774 438267

3. 68 438760 439254 439748 440242 440737 441232 441727 442223 442719 443216

3. 69 443713 444210 444708 445206 445704 446203 446702 447201 447701 448201

3. 70 448702 449203 449704 450206 450708 451211 451714 452217 452721 453225

3. 71 453729 454234 454739 456244 455760 456257 456763 457270 457778 458286

3. 72 458794 459303 459812 460321 460831 461341 461851 462362 462873 463385

3. 73 463897 464409 464922 466435 465949 466463 466977 467492 468007 468522

3. 74 469038 469654 470071 470588 471105 471623 472141 472660 473179 473698

3. 75 474218 474738 475258 476779 476300 476822 477344 477866 478389 478912

3. 76 479435 479959 480483 481008 481533 482058 482584 483110 483637 484164

3. 77 484691 485219 485747 486275 486804 487333 487863 488393 488923 489454

3.78 489985 490616 491048 491580 492113 492646 493180 493713 494247 494782

3. 79 496317 495852 496388 496924 497461 497998 498535 499073 499611 500149

3. 80 500688 601227 501767 502307 502847 503388 503929 504471 505013 505556

3. 81 506098 606641 607186 507729 508273 508818 509363 609908 510454 611000

3. 82 511547 612094 612642 513190 613738 514287 514836 515386 516935 616485

3. 83 517036 617587 518139 518690 519243 519795 520348 520901 521455 522009

3.84 522564 523119 523674 624230 624786 626343 626900 526457 527015 527673

3. 85 528132 528691 529250 529810 630370 530930 531491 532053 532614 633176

3. 86 533739 634302 634865 535429 535993 536658 537123 537688 538254 638820

3.87 639387 539954 540521 641089 641667 542226 542796 543364 543934 544504

3. 88 545075 546646 546218 546790 647362 547935 648508 649082 649656 650230

3. 89 550805 551380 551956 552631 653108 553684 554262 554839 565417 555995

3.90 556674 557163 567732 558312 558893 559473 660054 560636 661218 561800

3. 91 662383 562966 563550 564133 664718 565303 666889 566474 567060 567647

3. 92 568234 668821 569409 569997 570686 571176 671764 672354 572944 673535

3. 93 674126 574717 575309 575902 576494 577087 677681 678275 578869 579464

3. 94 680059 680656 581261 581847 582444 583041 583639 584237 584836 585435

3. 96 586034 686634 587234 587835 588436 589037 589639 590241 590844 591447

3. 96 592061 692656 593269 593864 594470 595076 595681 596288 596895 697602

3. 97 598110 598718 599327 599936 600545 601155 601766 602376 602987 603598 3.98 604210 604822 605435 606048 606662 607276 607890 608505 609120 609736

3. 99 610362 610969 611586 612203 612821 613439 614058 614677 615297 616917

4. 00 616637 617158 617779 618401 619023 619645 620268 620891 621516 622139

4.01 622764 623389 624014 624640 625266 625893 626520 627148 627776 628404

4. 02 629033 629662 630292 630922 631563 632184 632815 633447 634079 634712

4. 03 636345 635979 636613 637247 637882 638517 639153 639789 640426 641063

4. 04 641700 642338 642976 643616 644254 644894 645534 . 646174 646815 647467

4. 05 648099 648741 649384 650027 650671 661315 651959 652604 653249 653895 4.06 654541 655188 655836 656482 657130 657778 658427 659076 659726 660376

4. 07 661026 661677 662328 662980 663632 664284 664938 665591 666245 666899

4. 08 667554 668209 668865 669521 670177 670834 671491 672149 672807 673466

4. 09 674125 674784 675444 676105 676766 677427 678089 678751 679413 680076

10
Table I. Vapor pressure of He* {1958 scale) in microns {lOr^ mm) mercury at 0° C and standard gravity {980.665 cm/sec^) —Con.

• T°K 0.000 0.001 0.002 0.003 0.004 0.006 0.006 0.007 0.008 0.009

4. 10 680740 681404 682068 682733 683398 684064 684730 686397 686064 686731

4.11 687399 688067 688736 689405 690075 690746 691416 692087 692769 693431

4. 12 694103 694776 695449 696123 696797 697471 698146 698822 699498 700174

4. 13 700851 701528 702206 702884 703562 704241 704921 705601 706281 706962

4. 14 707643 708325 709007 709689 710372 711056 711739 712423 713108 713793

4. 15 714479 715165 715852 716538 717226 717914 718602 719291 719980 720670 4.16 721360 722050 722741 723433 724124 724817 725509 726203 726896 727590

4. 17 728285 728980 729675 730371 731067 731764 732461 733159 733857 734556

4. 18 735255 735954 736654 747354 738055 738756 739458 740160 740863 741666

4. 19 742269 742973 743677 744382 746087 745793 746499 747205 747912 748620

4. 20 749328 750036 750745 751454 752164 752874 753684 754295 755007 755719

4. 21 756431 757144 757857 758571 769285 759999 760714 761430 762146 762862 4.22 763679 764296 765014 765732 766451 767170 767889 768609 769330 770051

4. 23 770772 771494 772216 772938 773662 774385 776109 775834 776559 777284

4.24 778010 778736 779463 780190 780918 781646 782375 783104 783833 784563

4. 25 785294 786025 786756 787488 788220 788953 789686 790419 791153 791888 4.26 792623 793358 794094 794831 795568 796306 797043 707781 798520 799259

4. 27 799999 800739 801480 802221 802962 803706 804447 805190 806934 806678

4. 28 807422 808167 808912 809658 810405 811162 811899 812647 813395 814144

4.29 814893 815643 816393 817143 817894 818646 819398 820151 820904 821657

4. 30 822411 823166 823921 824676 826432 826188 826945 827703 828461 829219

4.31 829978 830737 831497 832257 833018 833779 834641 835303 836065 836828

4.32 837592 838356 839121 839886 840651 841417 842184 842951 843718 844486

4. 33 845255 846024 846793 847563 848334 849104 849876 850648 851420 852193

4. 34 852966 853740 854514 855289 856064 856839 857616 858392 859169 859947

4. 35 860725 861504 862283 863062 863842 864623 866404 866185 866967 867750

4. 36 868533 869317 870101 870885 871670 872456 873241 874028 874815 875602

4. 37 876390 877178 877967 878757 879546 880337 881128 881919 882711 883503

4. 38 884296 885089 885883 886678 887472 888268 889064 889860 890657 891464

4. 39 892252 893050 893849 894649 896448 896249 897050 897851 898653 899455

4.40 900258 901061 901865 902669 903474 904279 905085 905891 906698 907605

4. 41 908313 909121 909930 910739 911549 912359 913170 913981 914793 915605

4.42 916418 917231 918045 918859 919674 920489 921306 922121 922938 923765

4. 43 924573 925391 926210 927029 927849 928669 929490 930311 931133 931956

4.44 932778 933601 934425 935249 936074 936899 937725 938551 939378 940206

4. 45 941033 941861 942690 943519 944349 945179 946010 946841 947673 948505

4. 46 949338 950171 951005 951839 952674 953509 954346 956181 956018 956855

4. 47 957693 958531 959370 960209 961049 961890 962730 963572 964414 965256

4. 48 966099 966942 967786 968631 969476 970321 971167 972013 972860 973708

4.49 974556 975405 976254 977104 977954 978804 979656 980508 981360 982213

4. 50 983066 983920 984774 985629 986485 987340 988197 989054 989911 990769

4. 51 991628 992487 993346 994206 996066 996927 996788 997650 998513 999376

4. 52 1000239 1001103 1001968 1002833 1003699 1004565 1005432 1006300 1007168 1008036

4. 53 1008905 1009774 1010644 1011514 1012385 1013266 1014128 1015001 1015874 1016747

4.54 1017621 1018496 1019371 1020246 1021122 1021999 1022876 1023764 1024632 1025511

4. 55 1026390 1027270 1028150 1029031 1029913 1030795 1031677 1032561 1033444 1034328

4.56 1035213 1036098 1036984 1037870 1038756 1039643 1040531 1041419 1042308 1043197

4.57 1044087 1044977 1045868 1046759 1047651 1048544 1049437 1050330 1051224 1052119

4. 58 1053014 1053910 1054806 1055703 1056600 1067498 1058396 1069295 1060194 1061094

4.59 1061995 1062896 1063797 1064700 1065602 1066505 1067409 1068313 1069218 1070123

4.60 1071029 1071935 1072842 1073749 1074666 1076565 1076474 1077383 1078293 1079203

4.61 1080114 1081026 1081938 1082850 1083763 1084677 1085591 1086506 1087422 1088338

4.62 1089254 1090171 1091089 1092007 1092926 1093845 1094764 1095686 1096606 1097527

4. 63 1098449 1099372 1100295 1101218 1102142 1103067 1103992 1104918 1105845 1106772

4. 64 1107699 1108627 1109555 1110484 1111414 1112344 1113274 1114205 1116137 1116069

4. 65 1117002 1117935 1118869 1119803 1120738 1121674 1122610 1123546 1124483 1125421

4. 66 1126359 1127298 1128237 1129177 1130118 1131059 1132000 1132942 1133885 1134828 167 1135772 1136716 1137661 1138606 1139552 1140499 1141446 1142393 1143341 1144290

4.68 1145239 1146189 1147139 1148090 1149041 1149993 1150946 1151899 1152862 1153806

4.69 1154761 1155716 1156672 1157629 1168685 1159643 1160501 1161460 1162419 1163379

4.70 1164339 1165300 1166261 1167223 1168186 1169149 1170112 1171076 1172041 1173006

4.71 1173972 1174938 1175905 1176873 1177841 1178810 1179779 1180749 1181719 1182690

4.72 1183662 1184634 1185606 1186580 1187553 1188527 1189502 1190478 1191453 1192430

4.73 1193407 1194385 1195363 1196342 1197321 1198301 1199281 1200262 1201244 1202226

4.74 1203209 1204192 1205176 1206160 1207145 1208130 1209116 1210103 1211090 1212078

4. 75 1213066 1214055 1215044 1216035 1217025 1218016 1219008 1220001 1220993 1221987 4.76 1222981 1223976 1224971 1225967 1226964 1227961 1228959 1229957 1230956 1231956

4.77 1232955 1233955 1234956 1235957 1236959 1237962 1238965 1239969 1240973 1241978

4.78 1242983 1243989 1244996 1246003 1247011 1248019 1249028 1250037 1251047 1252058 179 1253069 1254081 1255093 1266106 1257119 1268133 1259148 1260163 1261179 1262195

11
Table 1. Vapor pressure of He* {1958 scale) in microns {10"^ mm) mercury at 0° C and standard gravity (980.665 cm/sec'^) —Con. i

0.000 0.001 0.002 0.003 0 004 0 005 0 006 0 007 U.UUo 0 noQ

4. 80 1263212 1 9fifi9fifi 1IZDooUD 9Rfi^inR 1 9fiQQ9fi 1 97n^47 1IZ/971 ^ftQ ItJQy 1 979'iQI iz/zoyx

4. 81 1273414 1274437 1275461 1276486 1277511 1278536 1279562 1280589 1281616 1282644

4. 82 1283673 1284702 1285732 1286762 1287793 1288825 1289857 1290889 1291923 1292957

4. 83 1293991 1 9QQ1 1 9QQ1 79 loUUZlU 1 9ni OAQ 1loUZZof ^099tt7 1 ^10^^107 lOUOoZ

/

4. 84 1304367 1305408 1306449 1307491 1308534 1309577 1310621 1311665 1312710 1313756

4. 85 1314802 1315849 1316896 1317944 1318993 1320042 1321092 1322142 1323193 1324245 4.86 1325297 1326350 1327403 1328457 1329511 1330566 1331622 1332678 1333735 1334792

4. 87 1335850 1 3^7068 1341148 1 ^49911 ^4^979 lo^ooyo

4. 88 1346462 1 ^4R^Q9 1^^0794 looi / y

1 oozooy loooyz

/

1loo^yyu ^^4QQfi lOODUDO

4.89 1357136 1358207 1359278 1360350 1361422 1362495 1363569 1364643 1365718 1366794

4. 90 1367870 1371101 11O/10OC5 ^749^8 lO J O^lo 1lo^7fi4QQ / D^yy 1lo977t80 /

/

OaU

4. 91 1378662 1379745 1380828 1381912 1382996 1384081 1385167 1386253 1387340 138842g

4.92 1389516 1390605 1391694 1392783 1393874 1394965 1396056 1397149 1398241 1399335

4. 93 1400429 1 4m 'i94 IIU * UU

(

l^tUolUO 1 400904 1lrilUOU*fc 41 0^04

4. 94 1411404 1412505 1413606 1414708 1415810 1416913 1418017 1419121 1420226 1421332

4. 95 1422438 1423545 1424652 1425760 1426869 1427978 1429088 1430198 1431309 1432421

4. 96 1433533 1434646 1435760 1436874 1437988 1439104 1440220 1441336 1442454 1443572

4. 97 1444690 1 4,4fiQ9Cl 1 44Q1 71 1 4'\n9Q^l i '±D\JZaO 1451415 14 ^9 ^^8 1l^OODDZ 4t;Qfifi9 1 4(^478^

4. 98 1455911 1 4*181 fi9 1 4fi9fi71

4. 99 1467191 1468323 1469455 1470588 1471721 1472855 1473990 1475125 1476261 1477398

5. 00 1478535 1 47Clfi7^ 1 480^1

1 4S1 Qf^n 1 4ft49'?n 1 4Qt;Q7n llOOo/

1 48ft'i19 1 4R7fi'^4 1488797

5. 01 1489940 1491084 1492229 1493374 1494520 1495667 1496814 1497962 1499110 1500259

5.02 1501409 1502559 1503710 1504862 1506014 1507167 1508320 1509474 1510629 1511784

5. 03 lOi /o/u lOlO/OU loiyooy lOZlUOU 1 ^19991

lOZZZll 1 '^9^^7^

5. 04 1524535 1525698 1526861 1528025 1529190 1530356 1531522 1532688 1533856 1535023

5. 05 1536192 1537361 1538531 1539701 1540872 1542044 1543216 1544389 1545563 1546737

5. 06 1547912 1549088 1550264 1551441 1552619 1553797 1554976 1556155 1557336 1558516

5. 07 1 UUUOO'J lOCM^zy 11 ODD ^fifi7QQ ( yy lou / yoo 1l(JUi7l *ifiQ171J 1

5. 08 1.571546 1 ^797^4 lO/DOUO 10 / ( lyi 10 / oDoO 11 o"^70878 / yo / o 1 'iRI 070 1 89964

5.09 1583458 1584653 1585849 1587045 1588242 1589439 1590638 1591836 1593036 1594236

5. 10 10U1401 1IDUZUOO An9fi^fi 1luuuyji fin^infi? 1 fi0f>274

5.11 1607481 1608689 1609897 1611107 1612316 1613527 1614738 1615950 1617162 1618375

5. 12 1619589 1620803 1622018 1623234 1624450 1625667 1626884 1628102 1629321 1630541

5. 13 1 fi^7fl79 iDoyuyo 1lO^UOiil fiin^9i 1641547 1 fi4977'i

5. 14 1644000 1645228 1646456 1647685 1648914 1650144 1651375 1652606 1653839 1655071

5. 15 1656305 1657539 1658773 1660008 1661244 1662481 1663718 1664956 1666194 1667433

5.16 1668673 1669913 1671155 1672396 1673639 1674882 1676126 1677370 1678616 1679862

5. 17 1681108 iOooDUO 1 RQe^^ no 1iOooDUZ fiSSlRn9 luoyoot 1 fiol 1 nfi 1 692^ 'iQ

0. la lby4ooD 1696120 1697375 1698631 1699888 1701145 1702403 1 "jnocci l/U.iDDl 1 ( U4yzU

5.19 1706180 1707441 1708702 1709964 1711228 1712490 1713754 1715019 1716284 1717550

5.20 1718817 1720084 1721352 1722621 1723891 1725161 1726431 1727703 1728975 1730248

5. 21 1731.')21 1732795 1734069 1735345 1736620 1737897 1739174 1740452 1741731 1743010

5.22 1744290

Table II. 1958 He* vapor pressure-temperature scale, T in ° K as a function of P in millimeters mercury at 0° C and

standard gravity, 980.666 cm/sec^

p 0 1 2 3 4 5 6 7 8 9

0. 01 0. 7907 65 7972 61 8033 57 8090 53 8143 50 8193 47 8240 45 8285 43 8328 40 8368 39

.02 .8407 38 8445 35 8480 35 8515 33 8548 32 8580 32 8612 30 8642 29 8671 28 8699 28 .03 .8727 27 8754 26 8780 25 8805 25 8830 24 8854 24 8878 23 8901 22 8923 22 8945 22

.04 .8967 21 8988 21 9009 20 9029 20 9049 19 9068 20 9088 18 9106 19 9125 18 9143 18 .05 .9161 18 9179 17 9196 17 9213 17 9230 16 9246 17 9263 16 9279 15 9294 16 9310 15 .06 .9325 15 9340 15 9355 15 9370 15 9385 14 9399 14 9413 14 9427 14 9441 14 9455 13

.07 .9468 14 9482 13 9495 13 9508 13 9521 13 9534 12 9546 13 9559 12 9571 12 9583 12 .08 .9595 12 9607 12 9619 12 9631 12 9643 11 9654 11 9665 12 9677 11 9688 11 9699 11 .09 .9710 11 9721 11 9732 10 9742 11 9753 10 9763 11 9774 10 9784 10 9794 10 9804 10

. 10 .9814 10 9824 10 9834 10 9844 10 9854 9 9863 10 9873 10 9883 9 9892 9 9901 10

. 11 .9911 9 9920 9 9929 9 9938 9 9947 9 9956 9 9965 9 9974 9 9983 8 9991 9 .12 1. 0000 9 0009 8 0017 9 0026 8 0034 8 0042 9 0051 8 0059 8 0067 8 0075 8

.13 1. 0083 8 0091 8 0099 8 0107 8 0115 8 0123 8 0131 8 0139 7 0146 8 0154 8

. 14 1. 0162 7 0169 8 0177 7 0184 8 0192 7 0199 7 0206 8 0214 7 0221 7 0228 8

. 15 1.0236 7 0243 7 0250 7 0257 7 0264 7 0271 7 0278 7 0285 7 0292 7 0299 6

. 16 1. 0305 7 0312 7 0319 7 0326 6 0332 7 0339 7 0346 6 0352 7 0359 6 0365 7

.17 1. 0372 6 0378 7 0385 6 0391 7 0398 6 0404 6 0410 7 0417 6 0423 6 0429 6

. 18 1. 0435 6 0441 7 0448 6 0454 6 0460 6 0466 6 0472 6 0478 6 0484 6 0490 6

.19 1. 0496 6 0502 6 0508 5 0513 6 0519 6 0525 6 0531 6 0537 5 0542 6 0548 6

12
Table II. 1968 He^ vapor pressure-temperature scale, T in °K as a function of P in millimeters mercury at 0° C and

standard gravity, 980.666 cm/sec'^—Continued

p 0 1 2 3 4 5 6 7 8 9

0. 2 1. 0554 55 0609 54 0663 52 0715 49 0764 49 0813 46 0869 45 0904 44 0948 43 0991 41

. 3 1. 1032 41 1073 39 1112 38 1150 38 1188 36 1224 36 1260 35 1295 34 1329 33 1362 33

.4 1. 1395 32 1427 32 1459 31 1490 30 1620 30 1550 29 1579 29 1608 28 1636 27 1663 28

.5 1. 1691 27 1718 26 1744 26 1770 26 1796 26 1821 25 1846 25 1871 24 1896 24 1919 23

.6 1. 1942 24 1966 23 1989 22 2011 23 2034 22 2056 22 2078 21 2099 21 2120 21 2141 21

_ 7 1. 2162 21 2183 20 2203 20 2223 20 2243 20 2263 20 2283 19 2302 19 2321 19 2340 19

1. 2359 18 2377 18 2395 19 2414 18 2432 17 2449 18 2467 18 2485 17 2502 17 2519 17

.9 1. 2536 17 2553 17 2570 16 2586 17 2603 16 2619 16 2635 16 2651 16 2667 16 2683 16

1.

1. 2699 15 2714 16 2730 15 2746 15 2760 15 2775 15 2790 15 2805 15 2820 14 2834 15

1.

1. 2849 14 2863 15 2878 14 2892 14 2906 14 2920 14 2934 14 2948 13 2961 14 2975 14

1. 2 1. 2989 13 3002 13 3015 14 3029 13 3042 13 3055 13 3068 13 3081 13 3094 13 3107 12

1.

1.3119 13 3132 13 3145 12 3167 12 3169 13 3182 12 3194 12 3206 12 3218 12 3230 12

1. 4 1.3242 12 3254 12 3266 12 3278 12 3290 11 3301 12 3313 12 3325 11 3336 12 3348 11 1.5 1. 3359 11 3370 11 3381 12 3393 11 3404 11 3415 11 3426 11 3437 11 3448 11 3459 10

1.6 1. 3469 11 3480 11 3491 10 3501 11 3612 11 3523 10 3533 11 3544 10 3554 10 3564 11

1.7 1. 3575 10 3585 10 3595 10 3605 10 3615 10 3625 10 3635 10 3646 10 3656 10 3665 10

1.8 1. 3675 10 3685 10 3695 9 3704 10 3714 10 3724 9 3733 10 3743 9 3752 10 3762 9

1.9 1. 3771 9 3780 10 3790 9 3799 10 3809 9 3818 9 3827 9 3836 9 3845 9 3854 9

2 1. 3863 89 3952 86 4038 82 4120 80 4200 77 4277 75 4352 73 4426 71 4496 69 4565 67

3 1. 4632 65 4697 63 4760 63 4823 60 4883 60 4943 58 6001 56 5057 56 5113 55 6168 63

4 1. 5221 53 5274 51 5325 51 5376 49 5426 49 5474 48 5522 47 5569 47 5616 46 5662 45

5 1. 5707 44 5751 44 5795 43 6838 42 5880 42 6922 41 5963 41 6004 40 6044 40 6084 39

6 1. 6123 39 6162 38 6200 38 6238 37 6275 37 6312 36 6348 36 6384 36 6420 35 6455 35

7 1.6490 35 6525 34 6559 34 6593 33 6626 33 6659 33 6692 32 6724 32 6756 32 6788 32

8 1. 6820 31 6851 31 6882 31 6913 30 6943 30 6973 30 7003 30 7033 29 7062 29 7091 29

9 1. 7120 28 7148 29 7177 28 7205 28 7233 28 7261 27 7288 28 7316 27 7343 27 7370 26

10 1. 7396 27 7423 26 7449 26 7475 26 7501 26 7627 26 7562 26 7578 25 7603 25 7628 25

11 1. 7653 25 7678 24 7702 25 7727 24 7751 24 7775 24 7799 24 7823 23 7846 24 7870 23

12 1. 7893 23 7916 23 7939 23 7962 23 7985 23 8008 22 8030 23 8053 22 8075 22 8097 22

13 1. 8119 22 8141 22 8163 21 8184 22 8206 21 8227 22 8249 21 8270 21 8291 21 8312 21

14 1. 8333 20 8353 21 8374 21 8395 20 8415 20 8435 21 8456 20 8476 20 8496 20 8516 20

15 1.8536 19 8555 20 8575 20 8595 19 8614 20 8634 19 8653 19 8672 19 8691 19 8710 19

16 1. 8729 19 8748 19 8767 18 8785 19 8804 19 8823 18 8841 19 8860 18 8878 18 8896 18

17 1. 8914 18 8932 18 8950 18 8968 18 8986 18 9004 18 9022 17 9039 18 9067 17 9074 18

18 1. 9092 17 9109 17 9126 18 9144 17 9161 17 9178 17 9195 17 9212 17 9229 17 9246 16

19 1. 9262 17 9279 17 9296 16 9312 17 9329 16 9345 17 9362 16 9378 16 9394 17 9411 16

20 1.9427 16 9443 16 9459 16 9476 16 9491 16 9507 16 9523 16 9539 15 9554 16 9570 16

21 1. 9586 16 9602 15 9617 15 9632 16 9648 15 9663 16 9679 16 9694 16 9709 15 9724 16

22 1.9740 15 9755 15 9770 15 9786 15 9800 15 9815 16 9830 14 9844 15 9859 16 9874 15

23 1.9889 14 9903 16 9918 14 9932 15 9947 14 9961 15 9976 14 9990 15 0005 14 0019 14

24 2. 0033 15 0048 14 0062 14 0076 14 0090 14 0104 14 0118 14 0132 14 0146 14 0160 14

25 2. 0174 14 0188 14 0202 13 0215 14 0229 14 0243 14 0267 13 0270 14 0284 13 0297 14 26 2. 0311 13 0324 14 0338 13 0351 14 0365 13 0378 13 0391 14 0406 13 0418 13 0431 13

27 2.0444 14 0458 13 0471 13 0484 13 0497 13 0510 13 0523 13 0536 13 0549 13 0562 13

28 2. 0675 13 0588 12 0600 13 0613 13 0626 13 0639 13 0652 12 0664 13 0677 13 0690 12

29 2. 0702 13 0715 12 0727 13 0740 12 0752 13 0765 12 0777 13 0790 12 0802 12 0814 13

30 2. 0827 12 0839 12 0851 12 0863 13 0876 13 0888 12 0900 12 0912 12 0924 12 0936 13

31 2. 0949 12 0961 12 0973 12 0985 12 0997 12 1009 12 1021 11 1032 12 1044 12 1056 12

32 2. 1068 12 1080 12 1092 11 1103 12 1115 12 1127 12 1139 11 1150 12 1162 12 1174 11 33 2. 1185 12 1197 11 1208 12 1220 11 1231 12 1243 11 1254 12 1266 11 1277 12 1289 11

34 2. 1300 12 1312 11 1323 11 1334 12 1346 11 1357 11 1368 11 1379 12 1391 11 1402 11 35 2. 1413 U 1424 12 1436 11 1447 11 1468 11 1469 11 1480 11 1491 11 1502 11 1513 11 36 2. 1524 11 1535 11 1546 11 1657 11 1668 11 1579 11 1590 11 1601 11 1612 11 1623 11

37 2. 1634 10 1644 11 1655 11 1666 11 1677 11 1688 10 1698 11 1709 11 1720 11 1731 10

38 2. 1741 11 1752 11 1763 10 1773 11 1784 11 1795 10 1805 11 1816 10 1826 11 1837 11 39 2. 1848 10 1858 11 1869 11 1880 10 1890 10 1900 10 1910 11 1921 10 1931 11 1942 10

40 2. 1952 10 1962 11 1973 10 1983 10 1993 11 2004 10 2014 10 2024 10 2034 10 2044 11

41 2. 2055 10 2065 10 2075 10 2086 10 2095 10 2105 10 2115 11 2126 10 2136 10 2146 10

42 2. 2156 10 2166 10 2176 10 2186 10 2196 10 2206 10 2216 9 2226 10 2236 10 2246 10 43 2. 2255 10 2265 10 2275 10 2285 9 2294 10 2304 10 2314 10 2324 10 2334 9 2343 10

44 2. 2353 10 2363 9 2372 10 2382 10 2392 9 2401 10 2411 10 2421 9 2430 10 2440 10

45 2. 2450 9 2459 9 2468 10 2478 10 2488 10 2498 9 2507 9 2616 9 2525 10 2536 9 46 2. 2544 10 2564 9 2563 10 2573 g 2682 9 2591 10 2601 9 2610 9 2619 10 2629 9

47 2.2638 9 2647 9 2666 10 2666 9 2675 9 2684 9 2693 10 2703 9 2712 9 2721 9

48 2.2730 9 2739 9 2748 9 2757 10 2767 9 2776 9 2785 9 2794 9 2803 9 2812 9

49 2.2821 9 2830 9 2839 9 2848 9 2857 9 2866 9 2875 9 2884 9 2893 9 2902 9

50 2.2911 88 2999 87 3086 86 3172 85 3257 84 3341 83 3424 82 3506 81 3587 79 3666 79

60 2. 3745 78 3823 78 3901 76 3977 75 4062 76 4127 74 4201 73 4274 73 4347 71 4418 71

70 2.4489 71 4560 69 4629 69 4698 68 4766 68 4834 67 4901 66 4967 66 5033 66 5099 64

80 2. 5163 64 5227 64 5291 63 5364 63 5417 62 5479 61 5540 61 5601 61 5662 60 5722 59

90 2.5781 60 5841 58 5899 59 6958 57 6016 58 6073 57 6130 56 6186 67 6243 55 6298 56

13
Table II. 1968 He* vapor pressure-temperature scale, T in "K as a function of P in millimeters mercury at 0° C and

standard gravity, 980.665 cm/sec^—Continued

p 0 1 2 3 4 5 6 7 8 9

100 2. 6354 55 6409 55 6464 54 6518 54 6572 53 6625 54 6679 53 6732 52 6784 52 6836 52

110 uooo 52 6940 51 6991 51 7042 51 7093 50 7143 50 7193 60 7243 49 7292 49 4y

120 2. 7390 49 7439 48 7487 48 7535 48 7583 48 7631 47 7678 47 7725 47 7772 46 7818 47

130 2 7865 46 7911 46 7957 45 8002 46 8048 45 8093 45 8138 44 R1S9 45 S997 oZZ/ AA44 8971 oZ/ 1 AA44

140 2. 8315 44 8459 43 8402 44 8446 43 8489 43 8532 43 8575 42 8617 42 8659 43 8702 42

150 2. 8744 41 8785 42 8827 42 8869 41 8910 41 8951 41 8992 40 9032 41 9073 40 9113 40

160 2. 9153 40 9193 40 9233 40 9273 39 9312 40 9352 39 9391 39 9430 39 9469 oy^0 Q'^lOft youo Oo

170 2. 9546 39 9585 38 9623 38 9661 38 9699 38 9737 37 9774 38 9812 38 9860 36 9886 38

180 2. 9924 37 9961 36 9997 37 0034 37 0071 36 0107 36 0143 36 0179 36 0216 36 0251 36

190 3 0287 36 0323 35 0358 35 0393 36 0429 35 0464 35 0499 35 0534 34 0568 00 UDUO •J4 o4

200 3. 0637 35 0672 34 0706 34 0740 34 0774 34 0808 34 0842 34 0876 33 0909 34 0943 33

210 3. 0976 34 1010 33 1043 33 1076 33 1109 33 1142 32 1174 33 1207 33 1240 oz 11Z<Z 979 oZQ9 220 3! 1304 33 1337 32 1369 32 1401 32 1433 32 1465 31 1496 32 1528 32 1560 31 1691 31

230 oZ IDO^ 1 RQPl IDoO ^101 1 71 R 1/ ID 01 1747 01^1 11 778 / /o 01^1 IftOO louy 01 1lo4U fi40 OU^to 1ft70 lo/U Q1Ol 1001 lyui oU

240 3. 1931 31 1962 30 1992 30 2022 30 2052 30 2082 30 2112 30 2142 30 2172 30 2202 29 250 3. 2231 30 2261 30 2291 29 2320 29 2349 30 2379 29 2408 29 2437 29 2466 29 2495 29 260 3 2524 28 2552 29 2581 90 ZDlU ZO9R 2638 29 2667 28 2695 29 2724 28 2752 ZO9R Z/oU 97R0 9ft ZO

270 3. 2808 28 2836 28 2864 28 2892 28 2920 28 2948 28 2976 27 3003 28 3031 27 3058 28 280 3. 3086 27 3113 28 3141 27 3168 27 3195 27 3222 27 3249 27 3276 27 3303 27 3330 27 290 3 3357 27 3384 26 3410 97 ZD9R 97 3490 26 3516 27 3543 26 3569 ZO9fi ^l*10H ooyo 97Z<

300 3. 3622 26 3648 26 3674 26 3700 26 3726 26 3752 26 3778 25 3803 26 3829 26 3855 25

310 0. OooU 26 3906 25 3931 9f; ZD 3957 9*^ ZD 3982 26 dOOR 4UUo 25 4033 25 4058 25 4083 9fi ZD 4100 4iuy 9*1 ZO 320 3. 4134 25 4159 25 4184 25 4209 24 4233 25 4258 25 4283 25 4308 24 4332 25 4357 25 330 0. "tOoZ 94 'ilUD zo AA.'W tttOl 94 1400 94Z4 447Q 44 /y 9*; ZO 40U4 4*19R 40Zo 94 400Z Z^t 4576 9*1 ZO 4Rni 94Z4

340 3. 4625 24 4649 24 4673 24 4697 24 4721 23 4744 24 4768 24 4792 24 4816 23 4839 24 350 3. 4863 23 4886 24 4910 23 4933 24 4957 23 4980 24 5004 23 5027 23 5050 23 5073 24 360 3 5097 23 5120 23 5143 23 5166 zo 5189 23 5212 23 5235 23 5258 22 5280 23 oouo ZO

370 3. 5326 23 5349 22 5371 23 5394 23 5417 22 5439 23 5462 22 5484 22 5506 23 5529 22 380 3. 5551 22 5573 23 5596 22 5618 22 5640 22 5662 22 5684 22 5706 22 5728 22 5750 22 390 3 5772 99 5794 99zz 5816 99ZZ Oooo 99ZZ OoDU 21 5881 22 5903 22 5925 22 5947 21 oyoo 99ZZ

400 3. 5990 21 6011 22 6033 21 6054 22 6076 21 6097 22 6119 21 6140 21 6161 21 6182 22

410 3 6204 21 6225 91 fi94fi Zl91 DZD/ 91Zl 6288 21 6309 21 6330 21 6351 21 6372 21 6393 21 420 3^ 6414 21 6435 21 6456 21 6477 20 6497 21 6518 21 6539 20 6559 21 6580 21 6601 20 430 3 6621 21 6642 ZU90 6662 21 DDOO 90ZU fi70^ 91Zl 6724 6744 20 6764 21 6785 20 6805 90ZU

440 3, 6825 20 6845 21 6866 20 6886 20 6906 20 6926 20 6946 20 6966 20 6986 20 7006 20 450 3. 7026 20 7046 20 7066 20 7086 19 7105 20 7125 20 7145 20 7165 19 7184 20 7204 20 460 19 7243 9nzu /ZDo ly1Q 7980 ( ZOZ ZU 7^00 ' ouz ZU90 7^99 / OZZ 19 7341 19 7360 20 7380 19 7399 90ZU

470 3. 7419 19 7438 19 7457 20 7477 19 7496 19 7515 19 7534 19 7553 20 7573 19 7592 19 480 3. 7611 19 7630 19 7649 19 7668 19 7687 19 7706 19 7725 19 7744 19 7763 18 7781 19 490 0. <OUU 7R1Q ly 78*^8 / oOo 1Qly 7ftf^7 tout 110ft loiO 10ly 7R04 / oy4 19 7913 IS10 7931 19 7950 19 7969 1Rlo

oOO 3. 7987 19 8006 18 8024 19 8043 18 8061 19 8080 18 8098 19 8117 18 8135 18 8153 19

610 ^ (11 79 1 ft fil on 1<S ft9nft 1Qly 1 Qlo OZ40 1R10 OZDO 1Rlo 8281 IRlo 8299 18 8317 19 8336 18 520 3. 8354 18 8372 18 8390 18 8408 18 8426 18 8444 18 8462 18 8480 18 8498 18 8516 17 530 0. 0000 1 8 oOui 1 ft oooy lo1ft ft=ift7 1ft 10 oouo 11 7( ADZZ ftR99 1Rlo 8640 1Rlo 8658 18 8676 17 8693 18

540 3. 8711 17 8728 18 8746 18 8764 17 8781 18 8799 17 8816 IS 8834 17 8851 18 8869 17

650 3. 8886 17 8903 18 8921 17 8938 17 8955 18 8973 17 8990 17 9007 18 9025 17 9042 17 660 0. yuoy 1 7 yu( D

1 71 / yuyo 1 Qlo QUI yiii 1 71 / 01yizo98 11 7* 014*; yi40 11 7/ 9162 171 / 9179 17 9196 17 9213 17

570 3. 9230 17 9247 17 9264 17 9281 17 9298 17 9315 17 9332 17 9349 16 9365 17 9382 17 680 3. 9399 17 9416 17 9433 16 9449 17 9466 17 9483 16 9499 17 9516 17 9533 16 9549 17

590 0. 17000 17 9583 16 9599 17 yDiD ID 9632 17 9649 16 9665 17 9682 16 9698 17 9715 16

D0O 3. 9731 16 9747 17 9764 16 9780 17 9797 16 9813 16 9829 17 9846 16 9862 16 9878 16

610 3 9894 1 7 9911 16 9927 16 9943 16 9959 16 9975 16 9991 16 0007 17 0024 16 0040 16 620 4! 0056 16 0072 16 0088 16 0104 16 0120 16 0136 16 0152 16 0168 16 0184 15 0199 16 630 fl91 K ID 110fi n947 1 RID UZDo 1 RID 097Q UZ( y

1 RID uzyo 110\ 0^10 UOlU 16 0326 16 0342 16 0358 16

640 4. 0373 16 0389 16 0405 15 0420 16 0436 16 0452 15 0467 16 0483 16 0498 16 0514 16 650 4. 0530 15 0545 16 0561 15 0576 16 0592 15 0607 16 0623 15 0638 16 0653 16 0669 16 660 ID U/UU 10 (171 R U 1 10 1 R 10 U 1 OU 1 RID A74R U/4D 110 07R1 U ( Dl 10 0776 ID 0792 16 0807 16 0822 15

670 4. 0837 16 0853 15 0868 15 0883 15 0898 15 0913 15 0928 16 0944 15 0959 15 0974 15 680 4. 0989 15 1004 15 1019 15 1034 15 1049 15 1064 15 1079 15 1094 15 1109 15 1124 15 690 1 (; Xu 1 R 10 1 1 RQ iiDy 10 1 1 ft,< 1 414 1 1 Oft iiyo 10 101 Q izio 1 *; 10 1IZZO 99ft 10 1243 15 1258 15 1273 14

700 4. 1287 15 1302 15 1317 15 1332 14 1346 15 1361 15 1376 15 1391 14 1405 15 1420 15

710 4. 1435 14 1449 15 1464 14 1478 15 1493 15 1508 14 1522 15 1537 14 1551 15 1566 14 720 4. 1580 15 1595 14 1609 15 1624 14 1638 15 1653 14 1667 14 1681 15 1696 14 1710 15 730 4. 1725 14 1739 14 1753 15 1768 14 1782 14 1796 15 1811 14 1825 14 1839 14 1853 15

740 4. 1868 14 1882 14 1896 14 1910 15 1925 14 1939 14 1953 14 1967 14 1981 14 1995 14 750 4. 2009 15 2024 14 2038 14 2052 14 2066 14 2080 14 2094 14 2108 14 2122 14 2136 14 760 4. 2150 14 2164 14 2178 14 2192 14 2206 14 2220 14 2234 14 2248 14 2262 13 2275 14

770 4. 2289 14 2303 14 2317 14 2331 14 2345 14 2358 14 2372 14 2386 14 2400 14 2414 13 780 4. 2427 14 2441 14 2455 14 2469 13 2482 13 2496 14 2510 13 2523 14 2537 14 2651 13 790 4. 2564 14 2578 14 2592 13 2605 14 2619 13 2632 14 2646 13 2659 14 2673 13 2686 14

14
Table III. 1958 He^ vapor pressure-temperature scale, T in ° K as a function of P in centimeters mercury at 0° C and standard

gravity, 980.666 cm/sec ^

p 0 1 2 3 4 5 6 7 8 9

80 4 2700 135 2835 133 2968 132 3100 131 3231 131 3362 129 3491 128 3619 127 3746 126 3872 125

90 4 3997 124 4121 123 4244 122 4366 122 4488 120 4608 120 4728 118 4846 118 4964 117 5081 116

100 4 5197 116 5313 114 5427 114 5541 113 5654 112 5766 112 5878 111 5989 110 6099 109 6208 109

110 4 6317 108 6425 107 6532 107 6639 106 6745 105 6850 105 6955 104 7059 103 7162 103 7265 102

120 4. 7367 102 7469 101 7570 100 7670 100 7770 100 7870 98 7968 99 8067 97 8164 97 8261 97

130 4. 8358 96 8454 96 8550 95 8645 94 8739 94 8833 94 8927 93 9020 92 9112 92 9204 92

140 4. 9296 91 9387 91 9478 90 9568 90 9658 89 9747 89 9836 89 9925 88 0013 88 0101 87

160 6. 0188 87 0275 86 0361 86 0447 86 0533 85 0618 85 0703 84 0787 84 0871 84 095S 83

160 5. 1038 83 1121 82 1203 83 1286 81 1367 82 1449 81 1530 81 1611 80 1691 80 1771 80

170 5. 1851 79 1930 79 2009 79 2088 78 2166 78

Table IV. Temperature derivative, dP/dT, in millimeters Hg/° Kfor the 1958 He* vapor pressure-temperature scale. Tin millimeters

mercury at 0° C and standard gravity, 980.665 cm/sec^

I u.uu n 01 0 02 0 03 0 04 0 05 u.uo u.u/ u.u<s n no

0.5 0. 0005503 0. 0007383 0. 0009799 0. 001287 0. 001674 0. 002157 0. 002755 0. 003489 0. 004384 0. 005468

.6 . 006772 . 008329 .01018 .01236 . 01493 . 01792 . 02141 . 02644 . 03008 . 03540

7 04838 . UTJOUD 07501 08617 . uyouo 1125 i9Hn .8 . 1640 !l848 .2077 .2328 !2602 !2902 .3228 !3583 .3968 .4385

.9 .4835 .5320 .5843 .6406 .7008 .7654 .8346 .9084 .9871 1. 071

1. u 1. 000 1 462 J . 0/

1 R9A Z. \}\}o 9 94H

1.1 2. 395 2. 557 2. 728 2. 907 3. 095 3. 291 3.496 3.711 3.935 4. 169

1.2 4. 412 4. 666 4. 930 5. 205 5.491 5.788 6.096 6.416 6. 747 7. 090

1. o i. '±10 7. 813 8. 194 0. 00/ 8 993 9 413 10. 29 lU. iD 11 91

1 A. 11 79 12 22 12 73 13 26 13 81 14 37 14 95 16 64 16 15 Ifi 77

1.5 17. 41 is! 06 18^73 19! 42 20! 12 20! 84 21! 58 22! 33 23! 10 23.88

1.6 24. 68 25. 50 26. 33 27.18 28. 05 28. 94 29.84 30.76 31.69 32.64

1 7 33. 61 34. 59 35. 59 36. 61 37. 64 38 69 39. 76 40 84 41. 94 43 05 L8 44! 18 45! 33 46.' 49 47.' 67 48! 86 50! 06 51! 28 52! 52 53! 77 65! 03

1.9 56.30 57.59 58.89 60.20 61.52 62.85 64. 19 65.54 66. 91 68.28

69 65 71. 03 79 d.9 1 tz 73 81 75 20 76 60 77 99 79 39 80 79 R9 9ft OZ* ZU

2.1 83.60 85.00 86. 38 87.74 89. 09 90. 41 91.71 92. 96 94. 28 96.77

2.2 97. 31 98.88 100.5 102.1 103.7 105.4 107.1 108.8 110.5 112.2

110. y 115 7 117 1^ 121 0 122 9 124 7 126 5 128 4 i^n ^

2 4 132 1 134.

136 0 137 9 139 9 141 8 143 8 145.147. 8 149.

2.5 15L9 153! 9 156^0 158! 1 160!2 162!3 164!5 166! 6 168! 8 17l!o

2.6 173.2 175.4 177.6 179.8 182.0 184.3 186.6 188.8 191.2 193.5

2.195.

198. 2 200. 6 202. 9 205.

207.

210.212.215.

217.4

2.8 219.9 222.4 224.9 227.4 230.0 232.4 235.0 237.6 240.1 242.7

2.9 245.4 248.0 250.6 253.3 256.0 258.6 261.3 264.

266.8 269.5

3.0 272.3 275.

277.9 280.7 283.5 286.3 289.2 292.0 294.9 297.8

3.1 300.7 303.7 306.6 309.6 312.5 315.6 318.6 321.5 324.5 327.6

3.2 330.6 333.7 336.8 339.9 343.0 346.1 349.3 352.4 355.6 358.7

3.3 361.9 365.1 368.4 371.6 374.8 378.1 381.4 384.7 388.0 391.3

3.4 394.6 398.0 401.3 404.7 408.1 411.5 414.9 418.3 421.7 425.2

3.5 428.7 432.1 435.6 439.1 442.7 446.2 449.7 453.3 466.9 460.5

3.6 464.1 467.7 471.3 474.9 478.6 482.3 486.0 489.7 493.4 497.2

3.7 500.9 504.6 508.4 512.2 516.0 619.8 523.6 627.5 531.3 535.2 3.8 639.1 543.0 546.9 550.8 554.8 568.8 562.8 566.8 570.8 574.9

3.9 578.9 583.0 587.1 591.2 595.4 599.5 603.7 607.9 612.1 616.3

4.0 620.6 624.8 629.1 633.3 637.6 642.0 646,3 660.6 655.0 659.4

4.1 663.7 668.1 672.6 677.0 681.4 685.9 690.3 694.8 699.2 703.7

4.2 708.1 712.6 717.1 721.6 726.1 730.7 736.3 740.0 744.7 749.4

4.3 754.1 758.9 763.7 768.6 773.4 778.3 783.2 788.1 793.0 797.9

4.4 802.9 807.9 812.9 817.9 822.9 828.0 833.1 838.1 843.2 848.4

4.5 853,. 5 858.7 863.9 869.1 874.3 879.5 884.8 890.1 895.3 900.7

4.6 906.0 911.4 916.7 922.1 927.6 933.0 938.5 943.9 949.4 965.0

4.7 960.5 966.1 971.7 977.3 982.9 988.6 994.4 1000 1006 1011 4.8 1017 1023 1029 1035 1041 1046 1062 1068 1064 1070 4.0 1076 1082 1088 1094 1100 1107 1113 1119 1125 1131

5.0 1137 1144 1150 1156 1163 1169 1176 1182 1188 1195

5.1 1201 1207 1214 1221 1227 1234 1240 1247 1254 1260

5.2 1267 1274 1280

15
Table V. Auxiliary table for use in making hydrostatic head correction

Table gives values of the ratio between the density of liquid He I at its saturated vapor pressure and the density of mercury at 0° C. (P m centimeters mercury

at 0° C and standard gravity, 980.665 cm/sec2.) The density of mercury has been taken as 13.6951 g/cm^. If densities of liquid He I constitute critical data in an

analysis, examination of the original literature is recommended.

p 0 1 2 3 4 5 6 7 8 9

0 0.01 0754 37 0717 35 0682 33 0649 30 0619 29 0590 29

10 . 010561 27 0534 26 0508 26 0482 25 0457 24 0433 24 0409 23 0386 23 0363 23 0340 23 20 . 010317 22 0295 22 0273 22 0251 21 0230 21 0209 21 0188 21 0167 21 0146 20 0126 21 30 . 010105 20 0085 20 0065 20 0045 20 0025 20 0005 20 9985 20 9965 19 9946 20 9926 19

40 . 009907 20 9887 20 9867 19 9848 20 9828 19 9809 20 9789 19 9770 20 9750 19 9731 20

50 . 009711 19 9692 19 9673 20 9653 19 9634 20 9614 20 9594 20 9574 19 9555 19 9536 20 60 . 009516 20 9496 19 9477 19 9458 20 9438 19 9419 20 9399 19 9380 20 9360 20 9340 19

70 . 009321 20 9301 19 9282 19 9263 20 9243 19 9224 19 9205 19 9186 19 9167 20 9147 19 80 . uuyiJs 19 9109 19 9090 20 9070 19 9051 20 9031 19 9012 20 8992 20 8972 20 8952 20

90 . 008932 19 8913 20 8893 20 8873 20 8853 20 8833 21 8812 20 8792 21 8771 20 8751 21

100 . 008730 21 8709 22 8687 21 8666 22 8644 21 8623 21 8602 22 8580 22 8558 22 8536 23

110 . 008513 23 8490 22 8468 23 8445 23 8422 24 8398 23 8375 24 8351 24 8327 25 8302 24

120 . 008278 24 8254 24 8230 25 8205 26 8179 26 8153 26 8127 27 8100 26 8074 27 8047 28

130 . 008019 28 7991 28 7963 28 7935 29 7906 29 7877 29 7848 30 7818 31 7787 32 7755 32

140 . 007723 33 7690 32 7658 33 7625 34 7591 36 7555 36 7519 37 7482 38 7444 39 7405 41 150 . 007364 42 7322 43 7279 44 7235 46 7189 48 7141 49 7092 51 7041 53 6988 56 6932 59

160 . 006873 61 6812 64 6748 68 6680 73 6607 79 6528 87 6441 103 6338 130 6208 154 6054 190

170 . 005864 229 5635 287 5348

Table VI. Deviations of earlier scales from the 1958 scale," Tn-Tss in millidegrees

\ntX L55 55E 48 BS 37 32 29 24 L55 55E 48

° K " K

0.7 -1.1 +1.0 +0.4 +0.3 -18.4 -2.7 -2.1 3.0 -.6 -1.1 +5.6

.8 -1.2 +1.1 +.5 +.3 -20.4 -10.3 -2.3

.9 -1.3 +1.2 +.6 +.4 -31.9 -22.1 -17.3 -2.4 3.1 -.2 -1.

+6.0

3.2 +.2 -0.9 +8.0

1.0 -1.5 +1.3 +.3 +.4 -26.8 -23.5 -23.5 -2.6 3.3 +.7 -.7 +8.6

1.1 -1.6 +1.4 -.2 +.4 -21.5 -24.7 -28.5 -2.7 3.4 +1.3 -.6 +8.7

1.2 -1.7 +1.5 +.4 +.5 -15.2 -25.4 -32.

-2.8 3.5 +1.9 -.3 +8.8

1.3 -1.8 +1.5 +.3 +.6 -8.

-25.7 -34.1 -3.0 3.6 +2.5 -. 1 +8.7

1.4 -1.9 +1.6 +1.0 +.8 -2.3 -25. 5 -34.5 -3.2 3.7 +2.9 0 +8.6

1.5 -2.0 +1.6 +1.3 +1.2 +1.1 -24.7 -33.2 -3. 5 3.8 +3.2 0 +7.7

1.6 -2.1 +1.5 +2.9 +1.8 +2.6 -23. 2 -30.3 +0.2 3.9 +3.2 -.1 +6.6

1.7 -2.

+1.4 +3.8 +2.6 +3.2 -21.0 -25.9 +33.0 4.0 +3.0 -.2 +5.0

1.8 -2.2 +1.1 +3.9 +3.4 +3. 5 -18.0 -20.2 +58.6

1.9 -2.2 +0.8 +5.1 +4.1 +4.2 -14. 2 -13.3 +78.5 4.1 +2.4 -.3 +2.6

4.2 +1.2 -.6 +0.5

2.0 -2.2 +.6 +6.0 +4.6 +5.6 -9.7 -5.6 +93.6 4.3 0 -1.0 -.4

2.1 -2.2 +.6 +8.4 +5.1 +7.1 -4.5 +2.5 +104. 5 4.4 -.9 -1.4 +.9

2.2 -Z2 +.8 +9.4 +9,3 +8.2 +8.2 +111.2 4.5 -1. 5 -1.9 +3.8

2.3 -Z 1 +.5 +8.5 +8.2 +7.0 +7.0 +113.

4.6 -1.7 -2.3 +7.7

2.4 -2.0 0 +7.0 +6.9 +5.4 +5.4 +111.2 4.7 -1.5 -2.8 +11.9

2.5 -1.9 -.4 +5.6 +5.5 +3.8 +3.8 +106.8 4.8 -0.9 -3.2 +15.8 2.6 -1.8 -.7 +5.0 +4.4 +2.1 +2.1 +100. 7 4.9 +.2 -3.7 +18.6

2.7 -1.5 -.9 +4.5 +3.6 +0.6 +0.6 +93.4 5.0 +1.7 -4. 1 +19.0

2.8 -1.3 -1. 1 +3.6 +3.4 -.9 -.9 +85.2

2.9 -0.9 -1.

+4.7 +3.6 -2.2 -2.2 +76.3 5.1 +3.7 -4.5 +15.8

5.2 +6.3 -5.0 +6.5

BS 37

+4.2

+5.3

+6.7

+7.9

+8.7

+8.9

+9.0

+8.6

+7.5 +6.3

+4.7

+2.8

+1.1

-0.5

32 29 24

-3.5 -3.5 +66.8 -4.5 -5.2

-5.7

-4.5 -5.2

-5.7

+57.2

+47.7

+38.4

-5.9 -5.8

-5.5

-5.9 -5.8

-5.5

+29.4

+21.0

+13.2

-4.8

-3.9

-2.6

-4.8

-3.9

-2.6

+6.2

-0.1

-5.4

-0.9 -0.9 -9.6

+1.2

+3.7

+6.6

+1.2

+3.7 +6.6

-12.7 -14.6

-15.3

+10.0 +14.0

+18.5

+10.0

+14.0

+18.5

-14.6

-12.4 -8.8

+23.6

+29.3 +35.7

+23.6

+29.3

+35.7

-3.7 +3.0

+11.1

+42.6 +42.6 +20.8

+32.1 +45.0

" Explanatory notes concerning table of deviations of earlier scales from the

1958 scale: Tm: Defined by equation on p. 33 of Leiden Comm. No. 147b (Kamerlingh Onnes and Weber) and by last equation on p. 23 of Leiden Comm. Suppl. No. 49 (Verschaffelt). These equations yield equal pressures at about

1.69° K. Therefore, values up through 1.5° K were derived from VerschafTelt's equation and those above from that of KamerUngh Onnes

and Weber.

Tjt; Defined by eq (6) on p. 36 of Leiden Comm. No. 202c (Keesom, Weber, and

Schmidt). These equations give equal pressures at 2.1765° K. The

authors state in the last paragraph of the communication, p. 37, that the

first of the equations fits reasonably well the data of Comm. No. 147b up to 6° K. Therefore, deviations up to 5.0° K have been included in the table.

T32: Defined by the first of eq (6) on p. 36 of Leiden Comm. No. 202c (Keesom,

Weber, and Schmidt) and by the equation on p. 8 of Leiden Comm. No.

219a (Keesom). T3! and Ta are thus identical above the lambda point. These two equations are discontinuous by about 0.008° at 2.190° K and

this fact was noted by Kee.som (Leiden Comm. Suppl. 71d).

T37: Defined by Tsj together with curves in figure 1 of Leiden Comm. No. 250c (Schmidt and Keesom). Differences between T^^ and T%i were deter- mined directly from figure 1 with suflScient precision to determine dif- ferences between Tm and T37 to 0.1 millidegree. Tbs: Defined by eq (9) and curve of figure 4, p. 1212 of Trans. Faraday Soc. 35 (Bleaney and Simon, 1939). Part, or all, of this scale is sometimes

referred to as Tsd. In order to obtain differences between this scale and T{8, pressures were calculated from the equation and curve with

sufficient precision to yield differences to 0.1 millidegree.

( Continued on page 17)

16
Tit: Defined by tables I and II on pages TISS to T15S and by second equation on p. T152 of Proces-Verbaux des seances du Comit# International des Poids et Mesures 33B, T151 (1952). Values given in the table were

obtained in the following ways. First, values of the difference between

this scale and the 1958 scale were calculated at every 0.01° interval be- tween 0.95° and 4.25° K from data of table II on pp. T158 and T159. The tabulated values from 1.0° through 4.2° K were then obtained by

averaging the calculated differences between T—0.05° and T-|-0.05°, with

weights of H assigned to the values at T—0.05° and T+0.05° and unit weights to all values at intermediate temperatures. For example, the tabulated value at 2.0° K is actually 1/20 of the sum of the differences at

1.95° and 2.05° plus 1/10 of the sum of the differences at 1.96°, 1.97°, 1.98°,

1.99°, 2.00°, 2.01°, 2.02°, 2.03°, and 2.04° K. The tabulated values at

0.7°, 0.8°, and 0.9° K were obtained by calculating the pressure corre- sponding to each 0.01° interval between 0.65° and 0.95° K from the data on p. T153 of table I and averaging the results in the maimer just de- scribed. At 4.3° K and above, the tabulated values were obtained

directly from the equation given on p. T152. Tables and equation have

been published also by C. F. Squire, Low tempeTature physics, pp. 229

to 233 and p. 26 (McGraw-Hill Book Co., Inc., New York, N.Y., 1953). T65e: Defined by the uimumbered equations on p. 188, Low temperature physics and chemistry (Clement), Proc. Fifth Intern. Conf. (Univ. of Wisconsin

Press, Madison, Wis., 1958). Values of vapor pressure in milUmeters mercury at 20° C were calculated by the computer at the U.S. Naval

Research Laboratory (the NAEEC) and values in millimeters mercury

at 0° C were calculated by the computer at Los Alamos Scientific Laboratory (the MANIAC). The MANIAC calculation was used for obtaining the values in the table.

Tlss: Defined by table VII on p. 461, Progress in low temperature physics (Van

Dijk and Durieux), (Worth-Holland Publishing Co., Amsterdam,

Netherlands, 1957). Values below 0.9° K were obtained from the

tables mentioned in section 23 of the reference. Table VII mentioned

above is the same as table V published in Physioa 34, 1 (1958) and in Leiden Comm. Suppl. 113c.

Table VII. Auxiliary table for use in making corrections for

density of mercury at temperatures other than 0°C''

Table gives values of the ratio between the density of mercury at the indicated temperature (° C) and that at 0° C.

f C 0 1 2 3 4 5 6 7 8 9

10 0. 99818 800 782 764 746 728 710 692 674 655

20 .99637 619 601 583 565 547 529 511 493 475 30 .99457 439 421 403 385 367 349 331 313 295

« Smithsonian Physical Tables, Ninth Revised Ed., edited by W. E. Forsythe,

p. 163 (The Smithsonian Inst., Washington, D.C., 1954).

Equation for Computing Local Acceleration Due to Gravity ^- ^

Most frequently the vapor pressure is measured

as a distance between two mercury levels. After

corrections for capillarity and for the temperature

of the mercury and the scale have been applied,

the height, h, has to be reduced to standard gravity.

The reduced height, ho, can be computed from

Ao=^fi'/980.665. If the local value of g is unknown,

it may be computed with sufficient accuracy for

correcting the height of a mercury column from

^=980.632—2.586 cos 2<^. +0.003 cos 4<^ —0.0003086 H

where is the local latitude and H the local altitude

in meters. The unit of g is cm/sec^.

' Proces-Verbaux des stances du Comite International des Poids et Mesures

23, pp. 96 to 98, 114 to 118, 129 to 134 (1950).

2 Q. D. Garland, pp. 221, 222, Karl Jung, p. 564, Handbuch der Physik edited by J. Bartels 47, (Springer-Verlag, Berlin, 1956).

Washington, D.C.

17 U.S. GOVERNMENT PRINTING OFFICE: I960

THE NATIONAL BUREAU OF STANDARDS

The 8Cope of activities of the National Bureau of Standards at its major laboratories in Washington,

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