bluuebunny/crossref_metadata_2025 huggingface dataset:
DRYING PROBLEMS OF TERRA COTTA1
Authors: Kirkpatrick Frank A.
Published: June 2006

A description is given of the method of drying terra cotta and the results obtained at the plant of the Kansas City Terra Cotta and Faience Company of Kansas City, Mo., a plant having a production capacity of 200 to 400 tons of terra cotta per month. The drying processes are found to be governed by a plant problem and a ceramic problem. The experience obtained has led to the decision to abandon large steam‐heated driers and build smaller units heated by natural gas.
NOTES ON FIRING IN DOWNDRAFT PERIODIC KILNS1
Authors: Linton Robert
Published: June 2006

The results of a series of investigations chiefly in connection with firing are presented, with a general discussion of factors entering into the heat treatment of silicate materials. These include (1) factors controlling firing, (a) specific heat of the clay body, (b) heat of dissociation of the hydroxides, (c) latent heat of fusion, and (d) heat of reactions which take place under fusion, (2) fuel consumption and temperature rise, (3) heat distribution in the kilns, (4) firing economies, (5) cooling, and (6) dehydration and shrinkage.
NOTE ON THE SOLUBILITY OF FIRED BODIES IN HOT SULPHURIC ACID1
Authors: Bleinincer A. V.
Published: June 2006

This work is an application of the so‐called mineral analysis to bodies fired to a maximum temperature corresponding to cone 9, for the purpose of establishing a measure of the progressive vitrification. It is based on the assumption that the solubility of an earthenware body in hot sulphuric acid decreases with the temperature of firing, as the porosity decreases. In general, this was found to be true but in order to obtain consistent results it is necessary to maintain standardized conditions of procedure especially in the grinding of the sample and in the treatment with fuming acid. The procedure has shown solution of as much as 66 % of the anhydrous clay substance with a porosity of 17.9%.
A STUDY OF COLOR AND ITS APPLICATION TO CERAMIC ART1
Authors: Lenchner Theodore
Published: June 2006

Color is recognized as having three dimensions, (1) warmth or coolness, known as value, (2) lightness or darkness, known as value, and (3) brightness or dullness, or strength or weakness, known as intensity and chroma. Two existing color theories, the Prang and Munsell systems, are outlined. The proper application of colors is discussed.
SOME OBSERVATIONS ON TERRA COTTA PHYSICS1
Authors: Spurrier H.
Published: June 2006

An apparatus for determining a representative “over‐all” coefficient of thermal expansion of terra cotta under service conditions is described. Observations made show a decided contraction upon wetting the terra cotta and the temperature must be raised for the regaining of the original length. It is probable that the extent of mycelial capillaries is the determining factor of the magnitude of contraction. Further data obtained are presented and discussed.
USE AND ABUSE OF POWER IN HEAVY CLAY PRODUCTS PLANTS1
Authors: Millar C.A.
Published: June 2006

The use of crude power supplying contraptions by many small plants has been observed.The installation of water softening plants as a means of reducing power costs is suggested, as is the use of electric motors to drive individual units such as grinders or dry pans.
A CONVENIENT PLATINUM‐WOUND RESISTANCE FURNACE1
Authors: Edward Orton, JR.  , Krehbiel J. F.
Published: June 2006

Details of construction of the furnace are given including the principal platinum resistor, the two end coils, Chromel booster coil, shell, refractories, insulators, etc., with detailed drawings and photographs. The log and graphs showing the behavior of the furnace in cone 20 firing (1533°C) at rate of temperature increase of about 33°C per hour are given. The cost of the furnace, the controlling apparatus, and the temperature measuring equipment, are given in detail.

The furnace meets the requirements successfully, as to performance. Its practical value will depend on the life of the platinum resistor which cannot be foretold. In the thirty‐one firings so far completed no changes have been observed in the electric performance or apparent condition of the furnace. Its performance at the end of the first year's operation will be given in subsequent paper.
DORR CLASSIFIERS FOR CLAY WASHING1
Authors: Anable A.
Published: June 2006

The Dorr bowl classifier is described in detail and its use in purifying clay iscon‐ sidered. The methods of purifying a North Carolina kaolin by (1) aaettling flume and (2) a Dorr bowl classifier are compared. The advantages of the bowl classifier over the settling flume are (1) less labor required, (2) greater recovery of clay, (3) increased purity and greater uniformity of clay. The classifier is also applicable to the purification of secondary kaolins.
INCREASE IN REFRACTORINESS IN CERAMIC BODIES IN INTERRUPTED HEAT TREATMENT1
Authors: Henderson H. B. , Caldwell J. H.
Published: June 2006

The increase in refractoriness referred to here is usually termed freezing. The study was undertaken to overcome the tendency of pyrometric cones to set or freeze when subjected to prolonged heat treatment when the temperature is more or less fluctuating. The work includes a study of the freezing tendency of some natural clays, of several pottery bodies, and of pyrometric cones. A body was developed that does not freeze under the treatment that produces the phenomenon in the other materials tested but the cause is not established.
NOTES ON KALLAUNER AND SEGER METHODS OF RATIONAL ANALYSIS1
Authors: Fischer Wilbur F.
Published: June 2006

A comparison of the Seger, Kallauner, and calculated rational analysis is made, using a Florida kaolin and a Tennessee ball clay. Results obtained are observed and discussed.
THE PHYSICAL STRUCTURE OF REFRACTORY MATERIALS1
Authors: Curtis Thomas S.
Published: June 2006

The relation of physical structure to the performance characteristics is pointed out. It is shown that chemical composition is of value principally as a means of control of raw materials, the value of the end product being determined largely by the crystallographic relationship existing between grain and bond.
A LABORATORY FOR THE TECHNICAL CONTROL OF THE MANUFACTURE OF REFRACTORIES1
Authors: Trostel ByL. J.
Published: June 2006

A detailed description is given of the laboratories of the General Refractories Co. with an account of the manner in which the laboratory serves in research, operating control, sales help, process and product development, and in collaboration with technologists in coöperative associations.
FURTHER DATA ON OPERATING COST OF A PLATINUM‐WOUND RESISTANCE FURNACE1
Authors: Orton Edward , Krehbiel J. F.
Published: June 2006

The results derived on the cost of operating a platinum‐wound resistance furnace after one year's use, are presented.
A NEW APPARATUS FOR A RAPID SEDIMENTATION ANALYSIS1
Authors: Van Nieuwenburg C. J. , Schoutens Wa.
Published: June 2006

A new apparatus for the continuous determination of the cumulative distribution curve of particle size is described. It is based on the known principle of determining the changes in concentration in one definite layer. Instead of drawing off portions of the liquid, the changes are measured by the apparent weight of a suspended body. Two points of the curve are determined independently by measuring the residue in suspension and by an elutriation in the same vessel. A source of errors, the contraction of the crow section in the neighborhood of the suspended body, is eliminated. The apparatus makes it possible to determine reliable distribution curves with any liquid within a few hours and avoids some sources of errors of previous methods.
SUSPENSION OF GLAZES AND BARIUM CARBONATE WATER1
Authors: WillamLee P.
Published: June 2006

Heavy setting, fine grinding, raw clay substances, hydrochloric acid, acetic acid, and corn starch are being discussed as the factors and ingredients for the suspension of glazes and wilkinite as a substance which will aid suspension for glazes and barium carbonate water.
THE VACUUM SLIP PROCESS OF REMOVING AIR FROM CLAY BODIES1
Authors: Lapp G. W.
Published: June 2006

In this process the slip clay is passed through a tank and the air content is evacuated by boiling out. The ability of the clay filter cakes formed from this slip to reabsorb a small amount of air insures freedom from air in the pugged clay if the pug mill is efficient as it can be in compacting the clay, without adding appreciable air to the clay.

Freedom from gases results in a series of helpful conditions throughout the various stages of production.
FIRE‐TRAVEL IN CONTINUOUS KILNS1
Authors: Searle Alfred B.
Published: June 2006

A general comparison of tunnel kilns and other continuous kilns is made taking up such questions as size, condition of the brick entering the kiln, draft, and rate of firing. As this is based on European practice, discussions based on American practice are appended.
BLASTING PRACTICES IN CLAY MINES1
Authors: Coale C. H.
Published: June 2006

Blasting materials and methods are described and detail discussion given on the comparative effectiveness of the various explosives under the several conditions met with in clay mining. handle.
SOME PHYSICAL PROPERTIES OF ARTIFICIAL ALUMINOUS ABRASIVES1
Authors: Purdy Ross C. , MacGer A. Ernest
Published: June 2006

Specimens representing six different bond compositions in soft, medium, and hard grades of artificial aluminous grinding wheels were tested for various physical properties such as hardness, elasticity, expansion, mechanical endurance, impact strength, etc. It was found that the expansion of present commercial grinding wheels and abrasive bonds is much less than that of artificial corundum. The strength of the wheels increases greatly with increasing percentages of bond. The methods of making the various physical determinations are given along with their interpretation.
THE REQUISITE CONSISTENCY FOR A CASTING SLIP1
Authors: Shearer Walter L.
Published: June 2006

Producing desirable flowing quality in a slip is proposed as a means of controlling its casting quality. A conception of plastic flow as a property incapable of being measured in terms of an absolute unit such as may be applied to viscosity measurement is presented and a simple gravity flow tube consistometer of suitable dimensions for obtaining comparative tests upon casting slips or upon similar suspensions is described.

Only sufficient data are presented to aid in explaining or describing general principles or conceptions, to suggest means of obtaining desirable plastic flow and to show what the consistency of a vitreous sanitary ware casting slip now in use actually is. Stiffness, yield value, and starting pressure are regarded as the elements making up plastic flowing quality and it is necessary to take all three of these factors into account in order to specify the kind of flow obtained. The consistency of a casting slip which will produce good solid cast ware, described in terms of the test apparatus used in connection with this work, may be stated as follows: stiffness equals 60 cm. per cc. per sec.; yield value equals 20 cm.; plasticity ratio equals 2.5. Reference has also been made to the application of these Same principles to the control of glaze slips and to the testing of clays to determine their suitability for use in any process involving their plastic working properties
IMPORTANCE OF THE GLASS PHASE IN PORCELAIN1
Authors: Kraner Hobart M.
Published: June 2006

This paper discusses the probable developments taking place in porcelain during the firing and overfiring processes. Evidence is given for the belief that mullite solution in the glass may be the cause of change of characteristics of the porcelain. Observations in the clay‐flint‐feldspar system and in the magnesia‐alumina‐silica ternary are discussed in connection with the above subject.
STATISTICAL AIDS IN LOCATING POTTERY TROUBLES1
Authors: McAfee W. Keith
Published: June 2006

The importance of performance records in pottery production and the advantages of arranging performance data in proper time relationship are pointed out. An outline of pottery record system is appended.
INSULATION IN THE CERAMIC INDUSTRY1
Authors: Phoenix E. A.
Published: June 2006

The following subjects are discussed: (1) heat losses in ceramic kilns, (2) early attempts at reducing heat losses from kilns, (3) properties of an ideal insulation for kilns, (4) advantages of kiln insulation, and (5) various applications of heat‐insulating material in the glass plant.
A TUNNEL KILN INSTALLATION FOR PORCELAIN INSULATORS1
Authors: Fritz E. H.
Published: June 2006

Several novel features are to be found in this installation relating to the design and operation of the tunnel kiln. A description of these is given.
MASONRY FAILURES DUE TO VERTICAL SHEAR1
Authors: Heath Fred T.
Published: June 2006

Observations and analysis of masonry failures are presented in which vertical cracks result from shear. It is suggested that the scope of laboratory testing of masonry walls be broadened to include a study of vertical shear stresses, and that general conclusions regarding masonry strength take such tests into consideration.
NOTES ON DRY‐PAN AND WET‐PAN OPERATION1
Authors: Gallaher J. M.
Published: June 2006

The article is a discussion of the following points: (1) improvement in dry and wet pans with the introduction of high capacity heavy‐duty units to replace several units and requiring less power and maintenance; (2) engineering cost data with respect to economical operating speeds, results of which were obtained from an actual installation calculated on an average power rate; (3) relation of rotation rate to capacity, considering the effect of the speed of rotation on the efficiency of the emptying device; (4) the optimum size for economical operations at various capacities, an intelligent answer to which cannot be given without a thorough study of the many factors involved, some of which are discussed in the article.
RELATION BETWEEN THE TEMPERATURE CURVE AND THE EXPANSION CURVE IN THE SETTING OF PLASTER1
Authors: Williams F. J. , Westendick F. C.
Published: June 2006

The plan of the investigation was to determine the relation between the expansion curve and the temperature curve in the setting of plaster of Paris, which is manufactured by calcining gypsum at about 145°C in muffle or rotary cylinders. The setting of plaster results from the fact that when it is mixed with water the latter dissolves some of the hemihydrate which unites with the water to form the dihydrate. The first volume change is a contraction followed by expansion, due to the fact that the calcium‐hemihydrate (2CaSO4‐H2O) goes into solution, thus decreasing the volume. An equilibrium is reached when the solution is saturated and then the dihydrate (CaSO4‐H2O) crystallizes out, causing expansion. Apparatus, methods of testing, data, calculations and curves are given.
OPTICAL METHODS AS AN AID TO THE STUDY OF REFRACTORIES1
Authors: McVay T. N.
Published: June 2006

The application of the petrographic microscope as an aid to the study of designating impurities in raw materials has proved successful. By the same methods fired refractories may be classified and the effects of bonds tested. Optical tests should chiefly be used to supplement and not to displace other methods of examinations.
A METHOD FOR TESTING THE FINENESS OF PORCELAIN ENAMELS1
Authors: Cook H. L.
Published: June 2006

The sieve‐shaker method of testing is described and recommended for use as a means of testing the fineness of porcelain enamels. The initial expense of equipment is offset by the economy of having the enamels leave the mill room in proper condition.
THE EFFECT OF PARTICLE SIZE OF ZINC OXIDE ON THE CONSISTENCY OF GLAZE SLIPS1
Authors: Thomson H. G.
Published: June 2006

No brand of oxide on the market is known to the author which does not have to be calcined to obtain satisfactory results in glazes, and it is further noted that a small amount of PbO present in the various grades is an essential constituent for satisfactory calcination. Microscopic examination showed an increase in particle size after calcining, although differences in uniformity of size and shape existed. The effect of zinc oxide in glaze slips was found to be dependent on its particle size and shape. Therefore the control‐of consistency of a glaze is simplified by the use of a properly calcined zinc oxide, by which a higher gravity and a more thinning range is obtained.
CORRECTING TENDERNESS OF A SHALE BY CHEMICAL TREATMENT1
Authors: Simpson Harold E.
Published: June 2006

An attempt was made to increase the strength of a tender shale in both the green and dry states. Finer grinding, aging, and the addition of chemicals were the expedients used. Sulphuric acid increased the dry modulus of the shale up to 251% when used in concentrations up to 10%. This benefit was offset by a leaching of the color; 0.25% HCl and 0.25% tannic acid increased the dry modulus 42% and 72%, respectively. Organic binders as Bindex and glutrin showed a 100% increase. Two per cent Na2CO3 and 1% BaCO2 showed a 60% and 45% increase. Molasses plus yeast improved the machining and the green strength of the shale. Finer grinding of the shale to pass 28‐ mesh and aging for one week improved the dry modulus 75.7%.
A COMPARISON OF RESULTS OBTAINED WITH AN IMPACT MACHINE1
Authors: Turk Richard H.
Published: June 2006

A description is given of an impact machine having a pendulum of rigid design. An instantaneous mechanical release is used, eliminating the human element. Results of tests with this machine are given, showing the probable consistency of such a machine.
SERVICING OF KILN CARS1
Authors: Spurrier H.
Published: June 2006

A lubricant for car bearings was desired which would furnish maximum protection for the bearings and decrease power consumption as much as possible. The maximum operating temperatures reached by the bearings were ascertained and a suitable lubricant compounded, effecting the desired results. A plan for using the lubricant is presented.
FLUX FOR CHEMICAL ANALYSIS OF FUSED ALUMINA REFRACTORIES1
Authors: Read Edgar B.
Published: June 2006

A mixture of sodium carbonate and borax is suggested as a flux for the chemical analysis of fused alumina refractories. The elimination of boron by several evaporations with methyl alcohol was found to be unnecessary.
GYPSUM PLASTER IN THE CERAMIC INDUSTRIES1
Authors: Wiss J. E. , Camp T. P. , Ladoo R. B.
Published: June 2006

This paper deals with manufacture, properties, and uses of gypsum plaster in the various branches of the pottery industry, i.e., in white ware, stoneware, electric insulators, sanitary ware, etc., in the terra cotta industries, in plate glass, and for sundry minor ceramic uses.

The methods of producing calcined gypsum are briefly described and then follows a discussion of the physical and chemical properties of the three principal forms of calcium sulphate as used commercially, (1) crude gypsum, (2) calcined gypsum (gypsum plaster), and (3) gypsum casts of set‐up gypsum plaster.

The proper methods of mixing, blending, and casting plaster are described, with graphs showing effects of varying such factors as consistency, mixing time, etc. Methods of testing plasters are briefly discussed. Considerable attention is given to difficulties commonly encountered in the use of plaster, with causes and methods of coffeetion. This includes the use and abuse of plaster molds, such as “rotting” of molds, “burning” of molds, efflorescence, etc.

The properties of gypsum plaster can be varied within wide limits to meet special requirements. It is shown how the plasters used for pottery and terra cotta molds are quite different from those used in bedding plate glass.

The purpose of the paper is to give a more complete picture of how gypsum plaster may and should be used in theceramic industries.
THE SOLUBILITY OF FELDSPARS IN WATER1
Authors: Parmelee C. W. , Monack A. J.
Published: June 2006

The relative solubilities were determined by measuring the increase in pH value that results from the solution of feldspar in water. The maximum time used was 48 hours. Twenty‐gram samples of feldspar were immersed in 200 cc. of water in volumetric flasks. The pH values were determined colorimetrically after definite intervals of time. Care was taken to, exclude atmospheric carbon dioxide.

The conclusions are (1) there exists no definite relation between the ratio K2O/Na2O of a feldspar and its solubility in water; (2) certain peculiarities of the feldspars are carried throughout the work; (3) both high soda and high potash feldspar have almost equal solubilities in this work; (4) the data obtained indicate that there may be suffi‐ cient increase in pH value to affect the viscosity of casting slips. The relations between pH increase and time are shown by graphs and represented by equations. The equations are of the form H=T/(a+bT) and no relation exists between a and b and the ratio K20/Na2O. The error of the work is estimated to be approximately 5°.
A PROGRESS REPORT ON THE DEVELOPMENT OF AN ABRASION TEST FOR REFRACTORIES AT HIGH TEMPERATURES1
Authors: Shaw Joseph B. , Bair George J. , Shaw Myril C.
Published: June 2006

A report of progress in the development of a method of testing refractories for their resistance to abrasion at high temperatures. The method developed consists of a steel chisel point moving back and forth over faces of the brick clamped together. Eleven brick are tested at one time. The chisel is actuated by means of a jack hammer and is water‐cooled. The blow delivered vanes from 6.5 inch‐pounds at the beginning of the test to 13 inch‐pounds under the most severe conditions. The chisel has a rounded point l/8‐ch radius and 1 inch wide. Data show that the principle is correct and capable of differentiating between brick of varying resistances to abrasion at tempcratures as high as 1350°C.
THE REACTIVITY TEST FOR DETERMINING THE VALUE OF BARIUM CARBONATE AS A SCUM PREVENTATIVE1
Authors: Bennett A. Lee , Goodrich H. R.
Published: June 2006

A brief review of the causes of scumming and glaze peeling is given. The usual use of barium carbonate for the prevention of these defects is also outlined.

The reactivity test for barium carbonate and a suggested chemical analysis for soluble sulphates are described.

Reactivity values of various barium carbonates are reported, followed by a discussion of the practical value of the reactivity test. A specification for barium carbonate is recommended.
A SYSTEMATIC METHOD FOR THE INVESTIGATION OF SHEET‐IRON ENAMELS1
Authors: Andrews A. I.
Published: June 2006

A study was made of the compositions of twenty‐four sheet‐iron ground coats and twenty‐four sheet‐iron cover enamels. The results were plotted on triaxial diagrams and interpreted. Some laboratory results are given and the reading of triaxial diagrams is explained.
THE USE OF POLARISCOPES IN THE GLASS INDUSTRY1
Authors: Preston F. W.
Published: June 2006

The action of polarized light as a means for detecting strains in glass is interpreted along two distinct lines: one a simple mathematical treatment of the resolution of simple harmonic vibrations, the other by means of physical analogies. The purpose is to give a presentation which can be followed without any mathematical training and at the same time to give a slightly more complex discussion for the more advanced technologist. Various types of polariscopes for detecting and measuring strain are discussed.
MECHANICAL PROPERTIES OF SOME ROLLED AND POLISHED GLASS1
Authors: Guyer E. M.
Published: June 2006

A comparative study was made of the mechanical properties of several different kinds of rolled and polished glass. Young's modulus of elasticity and the transverse modulus of rupture were measured by the usual cross‐bending method. Impact modulus of rupture was measured by means of a special form of pendulum which gave results that were free from the effects of cumulative chipping. Wind resistance was measured with a special form of hydraulic loading machine designed to give uniform pressure of the test plate against the supporting frame. The apparatus is described in detail and the results of the measurements are given in a series of graphs and tables.
EFFECT OF FURNACE GASES UPON GLASS ENAMELS1
Authors: Geisinger E. E. , Berlinghof K.
Published: June 2006

The effect of various fuel gases of products of combustion, and pressures on bonding of ground coat, physical condition and gloss of the enamel were studied under laboratory controlled conditions to determine the comparative results of firing in open and muffle furnaces and with fuel of different sorts. The benefits of recuperation are shown to he in complete combustion rather than in excess oxygen. Very hot diluted air would increase the efficiency of either oil or gas burners and produce better enamels.
AN INVESTIGATION OF THE POSSIBLE USE OF CERTAIN CALIFORNIA CLAYS IN VITREOUS CHINA SANITARY‐WARE BODIES1
Authors: Dietrich W. F. , Meyer W. W.
Published: June 2006

A bonding clay from Riverside County, a plastic fire clay from Placer County, and a washed, white‐firing clay from Amador County, were tried in vitreous china sanitary‐ ware bodies. Descriptions and properties of the clays are given. Twenty trial bodies were tested. The bonding clay and the plastic fire clay were found unsatisfactory for use in this class of ware.

Based on laboratory tests, the use of the washed clay from Amador County, to the extent of 10 to 30% of the body mixture, is quite feasible. This would reduce the total production cost of ware manufactured in California plants by 1.0 to 2.5%, depending upon the location of the consumer and the proportion of local clay that can be utilized. A body containing 30% of the washed California clay and no English china clay proved to be as good as the standard type body used for comparison; while another mixture, containing 18% of the washed clay, was superior in many respects to the standard body. The effects of additions of ground biscuit, magnesium and calcium carbonates, and sodium chloride, were also determined.

Subsequent commercial tests in a whiteware plant showed that under the conditions prevailing in that plant, from 10 to 15% of the California clay was the maximum that could be used without increasing the vitrification temperature of the body. In this case, the California clay displaced a mixture of china clay and ball clay, rather than the china day alone. It was also necessary to alter slightly the silica‐feldspar ratio.
AN APPARATUS FOR THE DETERMINATION OF ADSORBED AIR1
Authors: Kraner Hobart M. , Snydgr Ray A.
Published: June 2006

Some possible ceramic applications of the Toepler mercury pump as employed in determination of gases in various materials are discussed. The procedure followed in measuring the gases given off by a clay slip at reduced pressures is described. It was found that 4.65% of gases by volume are removed from a sample of clay slip by reducing the pressure on the sample to boiling (25 mm.). An additional 0.18% of gases was cvolved between the boiling pressure and 1.8 mm. at which pressure the sample was dry.
BLISTERING PHENOMENA IN THE ENAMELING OF CAST IRON1
Authors: Krynitsky A. I. , Harrison W. N.
Published: June 2006

Physical defects in the castings, especially “sponginess,” will cause blisters, as will also fanlty composition or application of enamels. There are, however, differences in the tendencies of different sound castings to give blisters when enameled under identical conditions. The gases forming these blisters are CO and CO2.

A gray iron casting acquires in freezing and cooling a very thin surface skin, or “microchill,” of varying thickness and hardness. The data indicate that removal of this skin from sound castings eliminates blistering. During the enameling process the combined carbon of this skin tends to break down to a nascent, readily oxidizable form of carbon, which evolves CO and CO2. There are probably two kinds of nonblistering iron, one in which little combined carbon is present at the surface, and another in which it is stabilized. Some irons are more prone to give the “microchilled” layer than others. During the early stages of enameling both blistering and nonblistering irons evolve gas, which is attributed to quick oxidation of submicroscopic graphite and which escapes bcfore the enamel has fused to a retentive condition. Addition of graphitizing agents, such as silicon, may be beneficial, but the microchill is harder to avoid than the ordinary, or macrochill. Removal of the surface layer by deep sandblasting or “burning out” appears to be the most practical remedy for blistering of sound castings.
THE DEVELOPMENT OF AN ENAMEL ON A EUTECTIC BASIS1
Authors: Simpson Harold Ellis
Published: June 2006

The object of the investigation was to develop eutectic solvent for an enamel by the combination of several eutectics, then to add silica to increase the refractoriness of the enamel up to the limit of its capability to dissolve silica without endangering its bond to the metal body. This naturally involved a study of the entectic compositions of the RO–B2O3–SiO2 systems. Since the Na2O–B2O3‐SiO2, K2O–B2O3–SiO2, and PbO–B2O3‐SiO2 detormation eutectics are known a knowledge of the CaO‐B2O3‐SiO2 system was necessary. A study of the high B2O3 area of this system was made at approximately 4% intervals. A member high in CaO and SiO2, and which on repeated fusions showed practically 100% glass, was selected as a practical member to blend with the Na2O‐B2O3–SiO3 and the PbO‐B2O3–SiO2 eutedic to form a eutectic solvent for an enamel.

Combinations of these eutectics and the CaO‐B2O3‐SiO2 mixture were made and applied to cast iron by the dry process. Additions of SiO2 were also made to these enamels up to 1.5 molecular equivalents. The physical properties of these enamels such as brilliancy, smoothness of surface, texture, bonding power, solubility in water, and resistance to acid attack were also determined.
FORMING PRESSURE OF DRY‐PRESSED REFRACTORIES. PART I1
Authors: Birch Raymond E.
Published: June 2006

Making use of a hydraulic press which presses standard fire brick, eight commercial mixtures were investigated to determine the effect of varying the forming pressure. To obtain pressures higher than those used commercially it was necessary to reduce the moisture content. The bulk density of uifired brick is shown to have increased directly with the pressure, as did the transverse strength. These changes, however, are lessened at the higher pressures. By comparing the green bulk density of brick formed on commercial, mechanically actuated presses, with those pressed hydraulically at known pressures it is concluded that industrial forming presses are operated at comparatively low pressures. Fireclay bodies do not attain a state of maximum compressibility within the limits of the study but continue to contract with additional pressure.
THE CAUSES AND PREVENTION OF BULGING IN HAND‐MOLDED REFRACTORY SHAPES†
Authors: Richardson Gordon B
Published: June 2006

Bulging is a universal problem in the manufacture of large refractory shapes. It is discussed from the standpoint of molding, pressing, turning from the mold, drying, edging, firing, and air and gas pockets.
ACID‐RESISTING WHITE DRY PROCESS CAST‐IRON ENAMELS1
Authors: Andrews A. I.
Published: June 2006

Beginning with simple compositions containing only those constituents necessary to make a glass, additions were systematically made in the development and study of acid‐resisting enamels.

It was found that the acid resistance depends on the proper combination of constituents rather than the presence or absence of any particular material. It was shown that all fluorine compounds are detrimental to acid resistance but experience shows that some form of fluorine is necessary to obtain good quality opacity. Smelting, if properly done, milling, and firing have practically no effect on the acid resistance.
PROGRESS REPORT ON THE EFFECT OF FURNACE GASES ON THE QUALITY OF ENAMELS1
Authors: Andrews A. I. , Hertzell E. A.
Published: June 2006

The appearance of sheet‐steel enamels fired in atmopheres of nitrogen, carbon dioxide, sulphur dioxide, and Urbana city gas has been determined. A study of the effect of variations in the composition of sheet‐steel ground coats and sheet‐steel cover coats on their resistance to attack by sulphur gases has been made. Plans for future work on the problem are outlined.
FELDSPARS AND THEIR PECULIARITIES AS CERAMIC SOLVENTS1
Authors: Watts Arthur S.
Published: June 2006

Data are presented to combat the fallacy that the chemical composition of a feldspar is a definite indication of its behavior as a vitrifying agent in ceramic bodies. A general presentation of data on the pure feldspar types and their constitution and mode of occurrence in commercial deposits is made. The effect of solid solution vs. associated or mixed feldspars on the physical properties of feldspars of similar compositions is outlined and the character of associated quartz and muscovite (white mica) is considered. A proposed basis of classification depending on the fusion behavior of the feldspar in the presence of quartz, kaolin, and ball clay is made.
PROGRESS REPORT ON INVESTIGATION OF SAGGER CLAYS. VI The Life of the Sagger as Affected by Varying Certain Properties1
Authors: Heindl By R. A. , Mong L. E.
Published: June 2006

This report presents the results obtained in a study of sagger bodies and represents an enlargement of a similar study of a preliminary nature, the results of which have been published. The clays and grogs are combined to give bodies having wide variations in body structure and in the several properties which were studied. Data are given on the modulus of elasticity, transverse breaking strength, plastic flow, thermal expansion, and resistance to failure due to heat shock of thirty‐five laboratory prepared bodies and ten commercial bodies after firing at from one to three different temperatures. For comparative purposes data are given on two series of bodies, the one series containing coarse grog and the other fine grog. In addition body compositions were varied in order to compare the effect on sagger life of using open‐ and close‐firing grogs.
PROPORTIONING THE GRAIN SIZE IN CLAY REFRACTORIES1
Authors: Swain Stephen M. , Phelps Stuart M.
Published: June 2006

A brief review is given of previous work pertaining to proportioning of the particle sizes. Experimental work presented has to do with the proportioning of three sizes of flint clay. To the proportioned particle sizes there were added different amounts of plastic or bond clay. There are given the effects of proportioning upon density, porosity, and change during firing. Clays from two producing districts were used, and although the experimental work on these was comprehensive, similar work should be continued in plant‐scale operations. The summary presents the benefits which may be expected from proportioning particle sizes of fireclay mixes used in refractories.
A BRIEF ANALYSIS OF SOME RECENT DATA ON THE IMPACT STRENGTH OF GLASS1
Authors: PRESTON P. W.
Published: June 2006

This paper attempts to analyze results provided by Dr. Guyer and Mr. Shenvood, with a view to finding out if anything useful is being obtained from impact testing figures beyond what is gotten from static tests. It is shown that in general, with the aid of the rationalization proposed in the foregoing paper, the impact and static tests can be compared as a simple ratio, and that this ratio has a pronounced tendency to be constant for given conditions of testing.
THE EFFECT OF FURNACE ATMOSPHERES ON THE QUALITY OF CERTAIN TYPES OF GLAZES1
Authors: Watts Arthur P.
Published: June 2006

A research sponsored by the American Gas Association was begun at Rutgers University in January, 1929. One phase of this research is the determination of the effect of furnace atmospheres on glazes, By maintaining carefully controlled conditions all variables were eliminated except that of atmosphere. Tests were made in many atmospheres using several different glazes. These atmospheres were formed either of the individual products of combustion, of combinations of gases which simulated actual furnace conditions, or of the products of combustion of city gas.
A SYSTEMATIC STUDY OF SHEET‐IRON COVER ENAMELS1
Authors: Andrews A. I. , Bennett D. G.
Published: June 2006

Based on the limits of composition for sheet‐iron cover enamels as commercially used, a systematic field of compositions was plotted and studied. The results show the relation between composition and properties of these enamels. The acid‐resisting properties were studied and a treatment developed for improving it.
ADDITIONAL DATA ON STOKER‐FIRED TUNNEL KILN1
Authors: Kent G. G. , Rupp B. M.
Published: June 2006

A description is given of the stokers, their operation, the difficulties that were overcome in order to adapt them successfully to this type of work, and the method of handling the fuel from hopper cars to the kiln. The economies effected by the installation and the subsequent changes in methods of handling the product are also given.
SUGGESTED RELATIONS OF SODIUM SILICATE, ADHESION TENSION, AND ANGLE OF CONTACT TO LIQUID ABSORPTION IN CLAYS1
Authors: Whitlatch George I.
Published: June 2006

This is a report of progress of an investigation concerning the effect of electrolytes on the liquid absorption of clays tempered to maximum plasticity. Data curves are presented to show that sodium silicates do have an influence on absorption when the silicates are added to the tempering water. The observed results are explained on the basis that the sodium silicate reduces the angle of contact and increases the adhesion tension of the clay‐water system. The results of this paper are suggestive of a possible extension of this principle to explain, a t least in part, some of the phenomena of deflocculation and plasticity.
THE DETERMINATION OF ZINC IN REFRACTORY BODIES AND SLAGS1
Authors: Marbaker Edward E.
Published: June 2006

An earlier published method for the determination of zinc in discarded retorts and other refractory bodies was found to be accurate but too tedious for commercial work. An effort was made to develop a shorter method. It was found that the ordinary ammonia‐ammonium chloride separation of iron from zinc is not accurate in the presence of relatively large amounts of alumina. A rapid method involving the separation of zinc from iron and alumina under conditions involved in the analysis of refractory bodies was developed. The method consists in precipitating iron and zinc sulphides from an ammoniacal solution containing the three ions, in which the alumina is held in solution by the presence of citric acid, Methods for the determination of zinc are discussed and reasons given for the adoption of the gravimetric method involving the precipitation of zinc sulphide from a faintly acid solution.
THE INFLUENCE OF TIME ON THE MATURING TEMPERATURE OF WHITEWARE BODIES. II.1
Authors: Norton Charles L.
Published: June 2006

This investigation deals with the microscopic examination of three of the whiteware bodies which were described in Part I of this paper. With respect to the influence of time of firing upon the crystalline texture, it was found that with samples which showed the same degree of maturity by physical test, the long‐fired, low‐temperature samples showed more quartz solution as well as more mullite development than the samples fired more quickly at higher temperatures.
EFFECTS OF AUTOCLAVE TREATMENTS ON CERAMIC BODIES AND CLAYS1
Authors: Holscher H. H.
Published: June 2006

It has been found that porous ceramic bodies increase in volume and weight due to an autoclave treatment in which the ware is subjected to steam at a pressure of 150 pounds per square inch. The change is rapid at first but decreases as the time of treatment is increased. Typical American and English china clays also increase in volume but ball clays when fired to the same temperature as the china clays do not increase in volume. The effect of prolonged drying treatments after the autoclave treatment is also studied. Data given indicate that the changes in volume are not necessarily caused by rehydration of the clay within the body. Bodies containing clay, feldspar, and flint show a greater increase in volume than do the pure clay constituents. It is shown that the composition is a more important factor than absorption in determining the reaction of ceramic products to the autoclave treatments.
INVESTIGATION OF FELDSPAR AND ITS EFFECT IN POTTERY BODIES*
Authors: Geller R. F. , Creamer A. S.
Published: June 2006

The history and purpose of the investigation are outlined and reports are made on (1) fineness determinations, chemical analyses, softening range, softening points, “true” specific gravity, thermal expansion, and petrographic analyses of the individual feldspars; (2) the results of porosity, volume shrinkage during firing, color and translucency, mechanical strength, petrographic analyses, effect of feldspar used on relative “glaze fit,” thermal expansion, and elasticity determinations on vitreous and semivitreous bodies in which feldspar is the only variable component.
THE RESISTANCE OF SINGLE CLAY BODIES TO THE ACTION OF STEAM1
Authors: Deeds C. L.
Published: June 2006

Twelve whiteware bodies were made, consisting of 51.41%, clay, 10.69% North Carolina feldspar, and 37.9% flint, one clay being used in each body. Twelve clays were studied. The specimens made from these bodies were fired in the regular tunnel bisque kiln to cone 9, glazed on one side, and fired to cone 4 in the glost kiln. The trial pieces were then subjected to the autoclave test, with the steam at a pressure of 100 pounds per square inch, maintained for a period of 3 hours. Of three American ball clays none was found to have caused crazing. In the case of four domestic kaolin bodies, one crazed in part, two were noncrazing, and one shivered. Of five imported kaolins, one of the bodies was noncrazing. While lower absorptions bring about a craze‐resisting condition, it was shown that of two single clay bodies with practically the same absorption, one may resist the steam action and one may not. The structure of the clay is an important factor in this connection.
MECHANICS OF ENAMEL ADHERENCE, II
Authors: Rueckel Walter C. , King R. M.
Published: June 2006

The effect on adherence of the variation in the amount of cobalt oxide, nickel oxide, and manganese oxide, and the effect of atmosphere, air, oxygen, and nitrogen on ad‐ herence were studied. Enamels of same base but with varying amounts of the special oxides were made up, fired in the various atmospheres, and tested for adherence by drop‐ hammer impact methods and by flexure methods. A number of photographs of metallographic sections showing contact line between enamel and metal are given. General conclusions are (1) that adherence is not a function of the roughness of contact line, (2) that the adherence promoting effect of cobalt oxide is higher at 1.25% than at 2.5% or 5.0%, and (3) that the effect of oxygen and nitrogen in general is to decrease the adherence as measured by impact strength.
THE EFFECT OF PREPARATION AND CALCINATION TREATMENT ON THE PROPERTIES OF THE KAOLIN‐ALUMINA MIXTURES A1203. SiO2*
Authors: Riddle Frank H.
Published: June 2006

Calcined mixtures of kaolin and alumina were prepared by grinding for different lengths of time and firing the several grinds at different temperatures ranging from slightly above dehydration temperature of clay to 1700°C. The X‐ray diffraction patterns revealed several interesting points relative to the degree of combination of the oxides present.
ELECTRICAL RESISTIVITY OF SPECIALIZED REFRACTORIES*
Authors: White Harold E.
Published: June 2006

Tests were made of the electrical resistivity of twelve commercially used special refractory brick at temperatures up to 1300°C. Standard 9‐inch brick were tested using apparatus which is standard equipment and readily obtainable. Temperature lag was eliminated by constant heating over a prolonged period of time at given temperatures. Results obtained indicate a decrease in resistivity with prolonged heating for some classes of refractories.

Those refractories composed of minerals of the same petrographic classification appear to undergo the least change.
CONTROL OF PLASTICITIES OF CERAMIC SLIPS*
Authors: Shearer Walter
Published: June 2006

In terms of a given apparatus of suitable standard dimensions the plastic flow characteristics of various ceramic slips may be measured and recorded. Each slip has its characteristic plasticity which is a highly important factor in connection with its successful use in the specific process for which it is intended and this plasticity may be adjusted at will in order to obtain the most desirable working condition. The types of flow which have been arrived at through long experience and employed in the art even without a means of measurement arc shown for various commercial enamels, glazes, and body slips. A useful deflocculation test for the classification of clays and the testing of their uniformity from time to time is specified. This description covers a means for control or regulation of the slip whereby (1) uniformity may be obtained in the application of white or colored enamels and glazes, (2) crawling and “settling out” difficulties may be avoided, (3) uniformity of consistency for spray operation from week to week may be checked, (4) accuracy of batch mixing may be checked, (5) casting slip control may be effected, and (6) in general, any other property such as case of filter‐pressing or sieving which depends wholly or partially on a proper slip consistency may be held at the most desirable value.
FURTHER WORK IN THE EXPERIMENTATION AND APPLICATION OF UNDERGLAZE COLOR CRAYONS*
Authors: Smith Kenaeth E. , Stevens William
Published: June 2006

Various underglaze colors obtained from different ceramic color firms were mixed with gum tragacanth and molded into crayons. The preparation and use of the crayons for underglaze designing is discussed, and their advantages and disadvantages are pointed out through experimental results. The results were studied with an aim to using crayons instead of painting the colors on the bisque, as is now generally done. After more experimentation there is a possibility of developing the use of crayons for this purpose.
ON A NEW LIGHT‐SOURCE FOR ABSORPTION MEASUREMENTS OF GLASSES IN THE BLUE AND ULTRA‐VIOLET1
Authors: Cohn Willi M.
Published: June 2006

On metallic thorium, when bombarded with cathode rays, a blue glow may be observed in high‐vacuum as well as in gas‐filled tubes. The spectrum of this phenomenon is continuous, the maximum of intensity being (according to photograph determinations) at 4.500 Å. The spectrum has been observed from A000 to 2200A. Lamps making use of the emission of the blue glow on thorium are described and their spectra discussed. It is shown that the new light‐source has several advantages in comparison with other light‐sources now in use.
MICROSCOPIC EXAMINATION OF CERAMIC RAW MATERIAL AND FIRED PRODUCTS, A HELP IN PLANT CONTROL*
Authors: Rhode Irma , Harkort Hermann
Published: June 2006

Methods and manufacturing control benefit of petrographic analyses are described.
MISCELLANEOUS TERRA COTTA LABORATORY NOTES*
Authors: Goodrich H. R.
Published: June 2006

The following points are discussed in this paper: (1) green scumming, (2) black ash as a substitute for barium carbonate, and (3) colemanite overglazes for polychrcnne.
MICROSCOPIC TECHNIQUE IN THE INVESTIGATION OF ENAMEL COATING AND SOME OBSERVATIONS*
Authors: Mcgoean G. W.
Published: June 2006

The polishing equipment and the technique of polishing specimens of vitreous enameled metal are described. A discussion is given of the characteristics of various enamel defects which are illustrated by photomicrographs.
THE FLOW OF GLASS IN TANKS*
Authors: Flint F. C. , Lyle A. K.
Published: June 2006

The paper deals with the flow of glass in tank furnaces. Reference is given to previous work on this subject. Experimental data are given for water and other liquids and the physical principles are discussed. Illustrations indicate the direction of flow in a glass tank.