bluuebunny/crossref_metadata_2025 huggingface dataset:
THE SOLUBILITY AND FUSIBILITY OF SOME FELDSPAR FRITS1
Authors: Sortwell H. H.
Published: June 2006

Twenty frits were made covering the field 10–50% fused borax, 20–90% feldspar, and 0–30% calcium oxide. (1). The solubilities of the entire field were found to be less than 1.5% showing that the variations in composition in this field had less effect on the resulting solubility than the degree of smelting, and that all of the kits were sufficiently insoluble for use in glazes. The inclusion of CaO in the frit had a beneficial effect in decreasing the solubility. (2). The fusibilities were found to vary from 660° to 1050°C. Substitution of CaO for feldspar up to 10%, maintaining the borax constant, increased the deformation point, but further substitution in this direction had little effect. Substitution of either CaO or feldspar for borax appeared to raise the deformation temperature about the same in either case. A large part of the field was sufficiently fusible for easy working in the frit kiln.
KILN MANIPULATION IN RELATION TO SCHOOL AND STUDIO POTTERY1
Authors: Rhead By Frederick H.
Published: June 2006

A suggestion for a chart to be used in connection with the firing of studio and school kilns.

The use of the chart makes it possible to record the time element, amount of fuel, and the temperature curve.
SOLUBLE SALTS AND CLAY WARES*
Authors: Parmrlee Cullen W.
Published: June 2006

A résumé of the present knowledge of the causes and the prevention of “Scum” and “Efflorescence.” It is proposed that the term “Efflorescence” be restricted to designate the surface deposits appearing because of the presence of soluble salts in the clays or burned wares and that the term “Scum” be used to describe the salts formed by the action of gases upon the wares during the drying or burning operations.

Mention is made of the formation of a surface coating upon the ware soon after the kiln is opened, sometimes not appearing until some days after the ware is removed from the kiln. This scum is readily and permanently removed by the application of water.

Such a residue was found to consist of sodium sulfate and sodium chloride. It is suggested that its formation was due to the presence of sodium chloride in the fuel and its subsequent deposition on the burned ware where it was changed in part to the sulfate by the action of the oxides of sulfur evolved from the fuel.
THE MEASUREMENT OF THE PLASTICITY OF CLAY SLIPS12
Authors: Wilson Robert E. , Hall F. P.
Published: June 2006

The paper emphasizes the great need of a quantitative measure of the physical properties commonly included in the term “plasticity” of clays and clay slips. Various indirect methods previously suggested are likely to lead to erroneous conclusions, while measurement of the flow or apparent viscosity of clay slips made up with a constant amount of water is shown to give misleading results.

The work described in this paper is preliminary in nature and has been confined to a study of the properties of clay‐water mixtures in the casting rather than in the molding range. In the light of these results it is recommended that, instead of the vague term plasticity, the properties of a given clay, at least for casting purposes, be expressed in terms of (a) the water content required to give proper working consistency, and (b) the resistance of the resulting slip to small deforming forces (such as gravity). Specifically, use is made of a modified Bingham plastometer, and the figures reported are (a) the amount of water required to give a slip of a specified mobility, and (b) the yield value of the slip thus obtained.

The method is shown to be capable of giving quantitative figures for the yield values at constant mobility which correspond well with the customary qualitative ideas as to the plasticity of clays. The amount of water required to give constant mobility varies to a surprising extent, and does not appear to bear any definite relationship to the usual classifications of more or less plastic clays. It probably does parallel fairly well the shrinkage on drying.

Small amounts of acid or alkali are shown to have a negligible effect on the mobility of a clay slip, but a very large effect on the yield value, the variations being greater than the difference between a non‐plastic kaolin and a highly plastic ball clay. This brings out the necessity, and indeed the potential value, of carefully controlling the hydrogen‐ion content of the water used in making the slips.

Some preliminary data are given on the effect of additions of flint and similar non‐plastic materials to clay slips.

It is recommended that an attempt be made to agree upon standard dimensions for the capillary and the desirable mobility for various purposes, and that the plastometer then be used as a standard method of test in the ceramic industry.
THE RELATIONS BETWEEN COMPOSITION AND PROPERTIES OF ENAMELS FOR SHEET STEEL1
Authors: Danielson R. R. , Swbely B. T.
Published: June 2006

Very little has been reported on the relations existing between enamel composition and the properties except the resistance to acids. In this investigation a study was made of the relation between enamel composition and such properties of the enamel as expansion, strength and acid resistance, as well as the effect of the relative “fit” of the ground and cover coats on resistance of the enameled ware to impact and to thermal shock.

The work was done on fourteen ground coats and white cover enamels applied to eight‐inch dinner plates. The latter were tested for resistance to impact, to thermal shock, and to acetic acid. Determinations were made of the expansion and compression strength of the enamels before application to the steel.

Conclusions.—1. The replacement of boric oxide by sodium oxide in the enamels increased the coefficient of expansion. Fish‐scaling decreased with increase of ex‐ pansion, due to increases of sodium oxide.

2. The compressive strength of the ground coats appeared to decrease with re‐ placement of boric oxide by sodium oxide, although the reverse conditions occurred in the case of the cover enamels.

3. Impact on the parts of enameled ware not free to deflect, such as the curved corners at the bottom, gives a measure of the toughness of the enamel as applied on the steel. The resistance of the enamel on corners to impact apparently is a function of the inherent strength of the enamel rather than its “fit” on the ware.

4. For greatest resistance to thermal shock, the ware should be coated with a ground coat having a coefficient of expansion equal to or preferably greater than that for the cover enamel.

5. Acid resistance, while dependent on the enamel composition, is not affected in the same way for all enamels. For these particular cover enamels, resistance to acids decreased with replacements of boric oxide by sodium oxide.
FUEL OIL AS ADAPTED TO THE CHAMBERED CONTINUOUS KILN
Authors: Taylor Mark A.
Published: June 2006

A summary of equipment used and methods employed in firing a Youngren type kiln with fuel oil. Includes a description of storage tanks, pumps, heater, oil distributing system, meters and strainers, atomizing medium, burner headers, and burners. The kiln successfully burns a uniform, high quality ware, and has been in use eleven years, with oil as the only fuel.
REFRACTORIES FOR STOKERS
Authors: Bouton George I.
Published: June 2006

An outline is given of the general uses of refractories for stokers, and the requirements for an ideal fire brick. Temperatures which a refractory must stand are given and some of the troubles due to fluxing and spalling are described. Some analyses are made of typical brick and troublesome ash.
EFFECTS OF ACCELERATORS AND RETARDERS ON CALCINED GYPSUM1
Authors: Welch F. C.
Published: June 2006

Theories on the setting and the effects of accelerators and retarders on calcined gypsum are outlined. Accelerators and retarders as found by the writer and several other investigators are given, with comparative effect and any noticeable advantages or disadvantages of such instruments.
AN ELECTRIC FURNACE TEMPERATURE REGULATOR1
Authors: Bunting E. N.
Published: June 2006

The theory and operation of an electric furnace temperature regulator of the Wheatstone bridge type are discussed. The regulator is suitable for use with rectified alternative current as well as for direct current, and will maintain a close constant furnace temperature.
A RECENT INSTALLATION OF A HARROP TUNNEL KILN1
Authors: Gavin Gordon P. , Hartford Frank M.
Published: June 2006

The proper firing treatment for producing a large capacity of sanitary ware requires a car tunnel kiln of exceptional flexibility. A recent installation of a tunnel kiln, 360 feet 10¼ inches long, operating at cone 10 flat, is producing 540 pieces of bisque sanitary ware per day and has a firing cycle of 67½ hours.

Oil is depended on entirely for fuel, there being no auxiliary gas or coal burning equipment.

Humidity driers are used in connection with this tunnel kiln and derive all their heat from the waste heat of the kiln.
MEASUREMENT OF THE HEAT ABSORBED AND EVOLVED BY CLAYS DURING FIRING AND COOLING1
Authors: Navias Louis
Published: June 2006

Apparatus.—A vacuum calorimeter containing an insulated platinum resistance furnace is described for use in determining reaction heats, and the heat absorbed in raising the temperature of a material in the furnace from room temperature to 1200°C, and also the heat evolved in cooling down the material from 1200°.

Materials experimented with.—Four typical clays are employed, namely A‐1 English china clay, North Carolina kaolin, Tennessee ball clay No. 5, and Laclede‐Christy raw flint clay. The calorimeter is calibrated with pure quartz.

Results.—The numerical data obtained are assembled in Table IV. The quantity of heat absorbed per gram per degree on heating the air dried clays over the complete temperature range 25—1200° amounts to 0.50–0.55 calories, whereas the heat evolved on cooling the final products per gram per degree through the range 1200—700° is 0.23–0.29 calories.

The heat absorbed in the ranges 24—420°, 420—900°, and 900—1200°, together with the heat evolved in the ranges 1200—900°, and 900—700°, are also given for all of the above clays.
THE EFFECT OF SOME SUBSTITUTES FOR TIN OXIDE ON THE OPACITY OF WHITE ENAMELS FOR SHEET STEEL1
Authors: Danielson R. R. , Frehaper M. K.
Published: June 2006

The effect of replacements of tin oxide on opacity of enamels is always of interest. This investigation includes a study of some of the commercial substitutes for tin oxide in a standard frit as well as others which are not in common use. Zirconium oxide and sodium antimonate are apparently the best substitutes and rank very close to tin oxide. Next in order is zirconium silicate, although the purity of the material is of course very important. Opacity does not always increase with increase in amount of oparifier used. Proper calcination of opacifiers is of importance in their effect on opacity.

Visual estimation is not an accurate method for determining the opacity of enamels, although it may be suitable for classifying enamels for such purposes as stove work and table tops. For accurate determination of reflecting value, the method employed by the Colorimetry Section of the Bureau of Standards is described. This involves the use of the spectrophotometer apparatus with illumination box as developed at the Bureau and the calculation of the total diffuse reflection from the spectrophotometric data.
DETERMINATION OF THE DISTRIBUTION OF HEAT IN KILNS FIRING CLAY WARES1
Authors: Rice W. E. , Sherman Ralph A.
Published: June 2006

This paper presents a description of some methods of collecting data on the performance of ceramic kilns and an explanation of the formulae used in calculating heat accounts from the data. It is hoped that these methods may serve as a foundation for the formulation of a code for testing kilns in order that the efficiency of new kilns can be determined on a comparative basis.
THE ELECTRICAL RESISTIVITY OF REFRACTORIES1
Authors: Henry A. V.
Published: June 2006

The electrical resistivities of flint fire clay, kaolin, magnesite, sillimanite, silica, diaspore, Maryland, Italian and Indian talcs were determined at temperatures up to 1500°C. Tests were made in an atmosphere of nitrogen, by the Wheatstone bridge method, using 45‐volt 1000 cycle alternating current.

With the exception of magnesite, the rate of decrease of resistivity decreases with an increase in temperature. The investigation indicates that the resistivity of a complex ceramic body, especially if it is open and porous, is not constant for a given temperature above the temperature at which its most fusible mixture melts. Resistivity is affected by the amount of impurities present, decreasing with an increase of impurities. As was shown in the tests of Italian talc, the resistivity is not only dependent upon the amount of impurities, but also upon their distribution. Within the limits of the voltage used, the resistivity is independent of the potential applied.
THE SYSTEM: Al2O3.SiO2
Authors: Bowen N. L. , Greig J. W.
Published: June 2006

This paper deals with a study of the equilibrium relations of mixtures of pure alumina and silica at high temperatures. The results are expressed concisely in the form of an equilibrium, diagram and their bearing on ceramic problems is discussed.

The principal feature of the diagram is the absence of the compound Al2O3.SiO2, the only compound being 3Al2O3.2SiO2. Crystals of this latter compound occur in all alumina‐silica refractories. The optical properties of these crystals have been determined and are compared with those of sillimanite, Al2O3.SiO2, which has hitherto been regarded as the crystalline compound occurring in refractories and clay bodies in general.

The behavior of natural sillimanite on heating is discussed.
THE SIGNIFICANCE OF DRAFTS IN DOWN‐DRAFT, COAL‐FIRED KILNS1
Authors: Sherman Ralph A. , Lunger R. F. , Rice W. E.
Published: June 2006

The fundamental laws of gas flow are applied to the movement of gases through down‐draft kilns. Data on pressure conditions in four kilns are presented graphically. The cause of draft, the superiority of the down‐draft over the up‐draft kiln, the significance of stack draft, the relation of draft and excess air, features of kiln design, and the comparative merits of forced, induced and natural draft are discussed.
THE INVESTIGATION OF TERRA COTTA WORK AT THE BUREAU OF STANDARDS1
Authors: Eskesen Eckardt V.
Published: June 2006

Research is being made covering failures due to popping, grazing and spalling. This work has been going on for nine years, first under the direction of Professor Bleininger, and later on under Professor Bates.

One or two fellow Ceramic Engineers have been constantly engaged in this work. Vatious tests, such as freezing and thawing have been conducted for the purpose of testing different clay bodies and glazes submitted by the manufacturers.
A NOTE ON EARLY OPTICAL GLASS MAKING IN THE UNITED STATES1
Authors: Blau Henry H.
Published: June 2006

The manufacturing process employed and the products obtained in the early work on optical glass in the United States, are described in detail.
AN APPARATUS FOR MEASURING THE ABRASIVE HARDNESS OF GLAZES1
Authors: Scott W. J.
Published: June 2006

An apparatus for measuring the resistance to abrasion, or scratching, of glazes and possibly other materials is described. It provides, essentially, for the wearing away of the surface by means of standard cement sand, which is allowed to run through a funnel adjusted to deliver a definite amount of sand for a given time interval, and to strike the inclined surface of the test piece after falling a fixed distance. The loss in weight under this treatment is assumed to bear a definite relation to the resistance to abrasion.
PREPARING AND SPRAYING A GLAZE SLIP WITH ESPECIAL REFERENCE TO THE CONTROL OF THE VARIOUS OPERATIONS1
Authors: Twells Robert
Published: June 2006

The article describes methods at the Champion Porcelain Company in glazing porcelain cores for spark plugs. One‐day requirement of glaze slip is intimately mixed and ground in a pebble mill to pass 325 mesh, then stored separately and gently agitated for several days while firing, specific gravity and viscosity tests are being made. Careful records are kept regarding each batch. Some of the problems met in the preparing and spraying of the glaze slip are described.
CLAY SEWER PIPE MANUFACTURE. V.—THE INFLUENCE OF VARYING LIME CONTENT IN CLAYS UPON SOME PROPERTIES OF SALT GLAZES PRODUCED AT DIFFERENT TEMPERATURES1
Authors: Scaurecht H. G.
Published: June 2006

Purpose.—

The effects of CaO content in clay between 0.15 and 8.22% and the salt glazing temperatures between cone 02 and 10 on some properties of salt glazes were studied.

Brightness.—

As low as 1 % CaO will prevent clays from taking a bright glaze at low temperatures. Clays containing CaO can best be glazed at high temperatures, above cone 5, providing the Fe2O3 content is low. The type of glaze a clay containing CaO will take may be approximately predicted by calculating G in the following equation in which x1 x2, x3 and x4 represent the percentages of Al2O3, SiO2, Fe2O3 and CaO in the calcined clay and T represents the salt glazing temperature in °C.

image

When G is greater than 0, bright glazes were produced, when between −0.1337 and 0, semi matt glazes were obtained and when below −0.1337 matt glazes were produced.

Color.—

Clays high in both CaO and SiO2 produced greenish yellow glazes at cone 7 on clays containing 5.32%, Fe2O3 as is represented by the following equation:

image

When A is greater than 0, the greenish yellow glazes were obtained.

Thickness.—

Raising the salt glazing temperatures and lime content increased the thickness of the glassy and fused portion on the surface of the clays.
AVENTURINE GLAZES1
Authors: Parmelee C. W. , Lathrop John S.
Published: June 2006

The aventurine is a special type of the crystalline glaze in which the separation of isolated individual crystals in the magma gives rise to the characteristic appearance of flitters or spangles suspended in a glass. The glazes may exhibit all degrees of crystallization from a few minute crystals to crowding of the magma with crystals, thus forming a matt texture, or in extreme cases a rough unsightly surface.

Iron is most commonly used for this development, although chrome, copper and uranium aventurines have been mentioned in literature.

In this investigation, we are reporting the results obtained by various students who have participated in our program of a rather extensive study of these glazes. Some of the data have been had from class exercises, other portions have been the results of investigations conducted for theses.
THE PLASTIC PROPERTIES OF ENAMEL SLIP
Authors: Cooks R. D.
Published: June 2006

A simplification of the Bingham Plastometer, applicable to enamel slips, is described and the theory of plasticity discussed briefly.

It was found that increase in temperature or increase in water content of enamel'slips raised the mobility without greatly affecting the yield value. Addition of clay and of certain inorganic salts raised the yield value without changing the mobility. Sodium silicate reduced the yield value to zero and lowered the mobility.
THE LABORATORY TESTING OF ALUMINOUS REFRACTORIES1
Authors: Geller R. F.
Published: June 2006

Eight brands of high alumina refractories and two brands of fire clay refractories, which are used by the trade under conditions of service requiring resistance to the corrosive action of lime and cement clinker at high temperatures, were subjected to standard and modified laboratory tests for high grade refractories. Data obtained indicate the results which may be expected in the technical examination of this type of product.
SOME CONSIDERATIONS NECESSARY IN SELECTION OF REFRACTORIES FOR THE OPEN HEARTH1
Authors: Cornell Sidney
Published: June 2006

The kind, quality and quantity of refractory brick used in steel plant furnaces, coke ovens, blast furnace, open hearth and auxiliaries are discussed.

The factors that influence the life of refractory brick in the open hearth furnace, discussed numerically, with the economic situation indicated in monetary value.
CHROME REFRACTORIES FOR THE OPEN HEARTH2
Authors: Griffith Raymond E.
Published: June 2006

This is not a technical paper but a compilation of notes on chrome ore, and the various forms in which it is used in open hearth furnaces, with a discussion of recent improvements in chrome brick that have permitted their broader use. Also some performance data secured through the courtesy of many companies and individuals operating open hearth furnaces.
ROOF BRICK FOR THE OPEN HEARTH1
Authors: Harrison H. C.
Published: June 2006

The conditions under which a roof brick has to stand are considered and possible means of improving refractories in common use suggested. A brief mention is made of the possibility of utilizing other available refractories.
CHECKER BRICK FOR RESISTING ALKALINE SLAGS1
Authors: Booze M. C. , Flint F. C.
Published: June 2006

Checker brick of varying composition were tested by placing them in the regenerators of two glass tank furnaces. The operation of one furnace was representative of those making the usual grade of bottle glass while the other was operated at a considerably higher temperature and with a more corrosive dust.

The amount of corrosion of the checker brick varied directly with the silica content of the brick. Those highest in alumina gave excellent service in the regenerator operating at the lower temperature. In the other regenerator, however, the. dust adhered to the high alumina brick and tended to clog the regenerator while it apparently fluxed and drained off of those higher in silica, leaving free passage for the gases.

The brick were tested in the laboratory by making into cones with various percentages of the corrosive dust and determining the fusion point of the cones. The results agree closely with those obtained from the service tests.

Detailed results including partial analyses of the brick and flue dust are given.
ON THE STRENGTH OF HEAVY CLAY PRODUCTS
Authors: Griffith J. H.
Published: June 2006

The published strengths of standard clay products have been formulated in simple equations (1) for placing the information in a simple compass for architects and ceramists, (2) to show the law of variation in terms of properly chosen variables, (3) to aid in appropriate selection of variables in devising future tests. The author assumed that a plus or minus variation or “tolerance” of 10% from the averages found by tests would be acceptable to manufacturers and ceramic engineers and has endeavored to keep well within these limits.
MANUFACTURE OF REFRACTORIES BY DRY PRESS METHOD1
Authors: Hagar Earl
Published: June 2006

A brief description of the manufacture of refractories by the dry press method is given emphasizing the following points in the preparation of materials: (a) weathering, (b) grinding and tempering, (c) screening, (d) mixing; the pressing of shapes and the amount of pressure is described. Six points are given as advantages of the dry press method, chief of which are reduction in cost of manufacture and increase of life of ware.
LIMESTONE FOR SHEET GLASS MAKING1
Authors: Arthur Edwin P.
Published: June 2006

Quarry selection is suggested as a more rational basis for the specification of a limestone for making sheet glass than limits of chemical composition. Non‐representative sampling is recommended in testiug limestone for contamination.
AN X‐RAY STUDY OF NATURAL AND ARTIFICIAL SILLIMANITE
Authors: Norton John T.
Published: June 2006

Mechanical mixtures of alumina and silica in the molecular proportions of 1:1 and 3:2 as well as samples of pure kaolin, have been heated to temperatures above 1500°C and have been examined by the X‐ray diffraction method. The diffraction patterns obtained from these samples agree extactly with the pattern given by a sample of natural sillimanite, not only in the position of the diffraction lines but in their relative intensities. This indicates that the regularly arranged atoms of these two compounds must have identical positions. It is concluded that either the two compounds are identical or that each unit of the lattice of one compound contains a definite number of randomly arranged atoms which the other compound does not possess.
METHOD AND MANUFACTURE OF SEWER PIPE IN CANADA1
Authors: Millar Charles A.
Published: June 2006

Description of clays used and methods employed in production of sewer pipe in Canada.
DIFFERENTIATION BETWEEN MULLITE AND SILLIMANITE BY THEIR X‐RAY DIFFRACTION PATTERNS1
Authors: Navus Louis , Davey Wheeler P.
Published: June 2006

Natural sillimanite, mullite prepared by fusing alumina and silica, and calcined china clays and ball clays have been examined by the X‐ray diffraction method. Each photographic film contained on one half the pattern of mullite as the reference substance, and on the other half the pattern of one of the other materials. In this manner direct comparisons of the patterns were made. It is definitely concluded that, while the patterns of sillimanite and mullite resemble each other very closely, there are pronounced differences in the positions of certain limes, especially in the region of 2.12 A to 1.70 A, sufficient for differentiation and identification. It is further concluded that the crystalline phase of highly calcined china clays and ball clays consists of mullite and not of sillimanite.
PLANT PLANNING
Authors: Garve T. W.
Published: June 2006

A guide for plant planning is given concluded with flow sheets for heavy clay products from characteristic clays.
THE MANUFACTURE AND PHYSICAL PROPERTIES OF DRY PRESS BRICK
Authors: Kruson J. H. , Smith C. A.
Published: June 2006

The process of manufacture of dry press brick is described and physical differences between dry press and stiff mud brick are enumerated. The advantages of the dry press process are summed up as follows: (1) they are uniform in size and shape; (2) they have small spalling loss; (3) they have good fusion resistance; (4) their heat conductivity is less than brick made by other processes; and (5) they have a low rate of manufacturing costs.
WEARING AWAY OF TANK BLOCKS1
Authors: Ross Donald W.
Published: June 2006

A statement concerning the manner of the wearing away of tank blocks, factors affecting such wear, and detailed studies of surfaces of used tank blocks.
SOME PROPERTIES OF FUSED QUARTZ and OTHER FORMS OF SILICON‐DIOXIDE1
Authors: Watson H. L.
Published: June 2006

A compilation of data on the physical properties of silicon‐dioxide.
TEMPERATURE OF PYREX AND PORCELAIN IN SUNLIGHT1
Authors: Littleton J. T. , Shaver W. W.
Published: June 2006

The relative temperatures of Pyrex glass insulators and porcelain insulators in sunlight are determined in three ways. A computation using the radiation and convection heating equations gives a value of 93 °C as a maximum surface temperature of porcelain in sunlight, with an assumed shade temperature of 40°C. In a similar way 46.5° C was determined for the Pyrex insulator. Measurements are given of the rise in temperature under natural conditions of Pyrex and porcelain insulators mounted on pins. Temperature measurements were made by means of thermocouples cemented to the surface of the insulators. Extreme conditions were further obtained by means of tin reflectors. Under such conditions the experiments show that the temperature of the porcelain insulator increases on the average about three and one‐half times that of the Pyrex glass insulator.
THE MINERALS OF BENTONITE AND RELATED CLAYS AND THEIR PHYSICAL PROPERTIES1
Authors: Ross Clarence S. , Shannon Earl V.
Published: June 2006

Abstract

Bentonite is a very widely distributed clay material that is the result of the devitrification and chemical alteration of glassy volcanic ash or tuff. Bentonite should be used as the name of a rock derived from volcanic glass and it is commonly composed of the mineral montmorillonite but less often of beidellite. Its characteristic minerals are completely crystalline and have a micaceous habit, high birefringence and facile cleavage. It contains no gel colloids, and few of its crystal particles are so small as to reach “colloidal size.” It shows high adsorptive powers and this property is more dependent upon physical form than upon chemical composition. That is upon the micaceous structure and easy cleavage which give very great surface area and the‘felt‐like texture which facilitates permeability.

The clay minerals of the type here described resemble the micas in many ways, but do not seem to possess the marked chemical variability of that group. A large number of analyses of the clay minerals from bentonite indicates that the most widespread of these is montmorillonite with the formula (Mg, Ca)O A1203 5SiO2, nH20.

A reanalysis of the type montmorillonite from Montmorillon, France, gives the same formula, and the mineral has also been recognized in lithium‐bearing pegmatites and in fullers' earth.

A few bentonites are composed of beidellite, a mineral first identified from the gouge clay of ore veins. It has the formula A12O3·3SiO2·nH2O where n= about 4, and A1203 may be partly replaced by Fe203.

A third micaceous clay mineral has the composition of halloysite Al2O3· 2SiO2· nH2O, but it is completely and visibly crystalline and has a high birefringence.
INSULATION OF CERAMIC KILNS1
Authors: Kennedy Walter
Published: June 2006

Abstract

Description and results of insulation are given.
THE MECHANISM OF SPALLING1
Authors: Norton F. H.
Published: June 2006

A study has been made of the stresses and fractures developed in a solid when rapidly heated or cooled. The stresses were measured in bakelite specimens by the photoelastic method. High stresses in all cases were found to occur near the surface of the solids, but no high tension stresses were present when the specimens were being heated. A number of vitreous clay spheres and bricks were heated and cooled rapidly and the nature of the cracks was noted. In practically every case the fractures occurred as predicted from the measured stresses. Torque‐deflection curves were obtained for a number of fire brick in torsion at different temperatures. The temperature at which plastic flow occurs for every material tested was approximately the same as the temperature of the initial deflection under compressive loads in a standard load test.
AN AUTOMATIC DEVICE FOR TAKING MOTION PICTURES AT REGULAR TIME INTERVALS1
Authors: Keenen F. G. , Bennett G. W. , France Wesley G.
Published: June 2006

An automatic apparatus for taking single photographic exposures at regular intervals of time over periods of from 12 to 36 hours was constructed. It consists of a large air thermostat and three mechanical units: (1) the thermal regulator, (2) the illuminating and optical system, and (3) the automatic mechanism controlling the camera and illuminating system. A detailed description of the construction and operation of the apparatus is given.
A LABORATORY PROCEDURE FOR DETERMINING THE DRYING CHARACTERISTICS OF CLAYS1
Authors: Casselman Elbridge J.
Published: June 2006

Directions are given for conducting a test for determining characteristics of clays. The reaction of the clays having good, intermediate, and poor drying qualities is described.
THE ANALYSIS OF SODA‐LIME GLASS1
Authors: Lundell G. E. F. , Knowles H. B.
Published: June 2006

In a discussion of the analysis of soda‐lime glass two types of methods must be considered: (1) the accurate or so‐called umpire or referee methods for determining the true composition of the glass, and (2) the less accurate but more rapid routine methods used in factory control. This paper deals primarily with the former.
LARGE CLAY SHAPES FOR THE WINDOW GLASS INDUSTRY1
Authors: Arthur Euwin P.
Published: June 2006

Service requirements of special clay shapes are discussed for the Lubbers, Colburn, and Fourcault window glass machines, and methods of making the shapes are mentioned.
THE HEAT‐BALANCE STUDY OF CERAMIC KILNS1
Authors: Bauiann Henry N.
Published: June 2006

The elements of the heat‐balance study and calculation of the thermal efficiency of ceramic kilns are summarized, and an outline of a heat‐balance method is given. The CO2 in the flue gases of the kilns studied was measured automatically and continuously by an electric CO2 meter making use of the thermal conductivity method, and some of the resulting CO2percentage curves are given and interpreted. A complete heat‐balance of a 30‐foot round downdraft facebrick kiln fired with wood is given, together with various data and conclusions on the use of wood in firing ceramic kilns. A complete heat‐balance of a Hoffman continuous coal fired kiln is given, together with temperature‐gradient curves and other data of this and two other Hoffman kilns.
ITEMS REQUIRING CONSIDERATION IN UNDERGROUND CLAY MINING1
Authors: Hearing R. H , Teppt C F
Published: June 2006

Two systems, the “advancing system” and “retreating system”, of operating the usual method of clay mining called “room and pillar work” are considered. The advantages and disadvantages of each system are presented. Details incident to mining, such as concentration of working area, frequent mapping of survey, haulage ways, room necks, pillars, and timbering are discussed.
A NOTE ON THIXOTROPY IN CLAYS
Authors: Stephenson H. H.
Published: June 2006

Thixotropy explains why potters in different plants, even when they buy the same clay, get different results.
Concerning new problems in the production of commercial glasses1 Mechanical Homogeneizing and the Correct Heat Treatment History
Authors: Eckert F.
Published: June 2006

Problems caused to arise by use of machine methods are greater uniformity in the molten glass and greater demands on the effective performance of the tank. Methods for producing homogeneous and defects encountered are discussed.
NOTES ON CYANITE AND DIASPOR REFRACTORIES1
Authors: Vachuska E. J. , Bole G. A.
Published: June 2006

This investigation covers a survey of some cyanite, diaspor, and clay refractories. The work is divided into three phases: (1) diasporcyanite study, (2) diaspor‐clay and cyanite‐clay study, and (3) commercial production and tests. Results of routine tests made with each set of test specimens are given. The addition of 20% or more cyanite to diaspor tends to counteract the shrinkage of diaspor during continued use at high temperatures.
DESIGN AND SERVICE OF TANK BLOCKS1
Authors: Ross Donald W.
Published: June 2006

Data are presented and some inferences are drawn concerning the manner in which properties of the tank blocks, their use and design, and the design of the tank itself, affect the life of the tank.
A STUDY OF FLUE LINING1
Authors: Hart R. A. , Clark H. W.
Published: June 2006

Investigations conducted on various types of Rue lining following the failure of several lengths in a chimney are described and data thereon are given. Standardization on a round tile lining with a minimum area of ninety‐five square inches, and having a modified tongue and groove joint is recommended. The resistance to rapid temperature changes should also be improved.
A NEW MERCURY VOLUMETER1
Authors: Weeeler E. S. , Kuechler A. H.
Published: June 2006

A new mercury volumeter is presented, which has certain features not possessed by others. Principle of operation, construction, manipulation, and calibration are discussed. Its advantages and disadvantages are listed.
SOME ASPECTS OF AMERICAN GLASS TANK FURNACE PRACTICE1
Authors: Thoureson Freu S.
Published: June 2006

A summary ot information secured in answer to a questionnaire dealing with some of the features of glass tank operation. Considerable variation in methods is shown by the replies given by twenty‐seven manufacturers.
MEASUREMENT OF PLASTICITY1
Authors: Talwalkar T. W. , Parmelee C. W.
Published: June 2006

The object of this investigation was to devise a rational method and primary standard for measuring plasticity. Various methods suggested in the past were critically examined and found wanting. An apparatus was developed to measure the stress‐strain relations of clays in shear and a few typical clays have been examined by this method. A definition is proposed for the unit of plasticity as follows:

Index of plasticity = Total deformation at fracture in shear / Average stress beyond proportional limit

The effect of addition of sand and powdered graphite has been noted and throws some light on the nature of plastic deformation.
AN INTERESTING COLOR PROBLEM1
Authors: Spurrier H.
Published: June 2006

A terra cotta glaze that had not previously shown any color suddenly burned to pink. The cause of the color was found to, be chromium communicated by the kiln atmosphere. An exceedingly delicate test for chromium and an interesting use of complementary color effects were developed.
FURTHER STUDIES ON PORTLAND CEMENT COMPOUNDS BY THE X‐RAY DIFFRACTION METHOD1
Authors: Hansen W. C.
Published: June 2006

In this investigation a study has been made of methods for preparing compounds of CaO with Al2O3 and SiO3 which may occur in Portland cements. The products from the different methods were studied microscopically and by the X‐ray diffraction method, and the X‐ray diffraction patterns for γ and β 2CaO·SiO2 and 3CaO·SiO2 are given.
STRENGTH OF BRICK IN TENSION1
Authors: McBurneyz J. W.
Published: June 2006

A self‐aligning grip for use in testing brick in tension is described. Values for the tensile strength of several types of brick are given. Comparison is made between the transverse and tensile strength of the brick. The conclusion is that the tensile strength is closely related to the transverse strength.
TERRA COTTA KILN SLAB INVESTIGATION1
Authors: Clare R. L. , Brown G. H. , Allen F. B.
Published: June 2006

Following several discussions as to the constitution of a good kiln slab for terra cotta manufacture, a coöperative test was made in which slabs of various compositions were manufactured by a producer of refractories, tested under actual service conditions, and physical measurements were determined by the Ceramic Department, Rutgers University. Series included the use of tight‐firing medium refractory clays, open‐firing refractory clays with grog, both vitreous and porous. Grogs were sized (definite proportions of size ranges constituting the different members). Conclusions were drawn as to effect of all these variables.
SIGNIFICANCE OF THE STANDARD FIRE TEST TO HEAVY CLAY PRODUCTS MANUFACTURE1
Authors: Foster H. D.
Published: June 2006

This paper points out the origin and basis of the fire‐test procedure, listing five places where fire tests of building walls can be made and the type of work done at these various laboratories. Some data are given to show the need and general trend of research work in heavy clay products leading to better fire resistance.
A STANDARD UNIT OF DIMENSION FOR MASONRY1
Authors: Heath Fred T.
Published: June 2006

Construction problems due to lack of coördination in sizes of different masonry materials are pointed out. It is proposed that these difficulties can be overcome by adoption of a standard “unit” of dimension to be used by architects and engineers in dimensioning building plans, and by masonry material manufacturers in determining the size of their products. No definite “unit” of measure is suggested, except that it should approximate one brick length plus one mortar joint, two brick widths plus two joints, or three brick thicknesses plus three joints. The application of the “unit” plan is given for face brick, common brick, paving block, fire brick, cement block, structural clay tile, terra cotta, cut stone, and to masonry openings for windows and doors. Illustrated with 74 photographs of masonry and 2 plates.
PROGRESS REPORT ON INVESTIGATION OF FIRECLAY BRICK AND THE CLAYS USED IN THEIR PREPARATION1
Authors: Heindl R. A. , Pendergast W. L.
Published: June 2006

This is a progress report of an extensive study of fire clays and fireclay brick. It includes the results of a preliminary study of clays representative of those used in the manufacture of refractories throughout the United States. Chemical analyses and a summary of physical tests are given of both fire clays and the brick manufactured from them. The thermal expansion behavior of the fire clays fired at 1400°C and those of the fire brick “as received” from the manufacturer and also after firing at 1400°C, 1500°C, and 1600°C were studied and the materials classified into groups having characteristic thermal expansions. The moduli of elasticity and rupture were determined at 20°C, 550°C, and 1000°C. The resistance of the brick to spalling in a water‐quenching test is expressed in an empirical relation correlating the elasticity, strength, coefficient of expansion, and percentage of grog used in compounding the brick batches. Data are presented on individual bricks made by the same manufacturer showing probable reasons for great differences in the number of quenchings required to cause spalling in the water‐dip test.
A CONSTANT‐PRESSURE GRAVITY TANK FOR SPRAYING SLIPS AND GLAZES1
Authors: Grady R. F.
Published: June 2006

The difficulties in obtaining even coatings with gravity feed and the uniform results obtained with a tank equipped with a Mariotte tube are described. The construction and use of the device are explained and illustrated.
CAUSE AND CONTROL OF COLOR VARIATION IN CAST‐IRON AND SHEET‐IRON ENAMELS1
Authors: Wenning W. F.
Published: June 2006

The need of uniformity and high quality in color chemicals for enamel ware becomes more important with the constant demand for colored enamel ware. The influence of opacifiers, enamel composition, and firing temperature on enamel colors is pointed out.
EFFECT OF WATER IN EXPANDING CERAMIC BODIES OF DIFFERENT COMPOSITIONS1
Authors: Schurecht H. G. , Pole G. R.
Published: June 2006

The effects of the composition of some ceramic bodies on their moisture expansions were investigated. With the exception of mixtures containing blast‐furnace slag or magnesite, most bodies with high absorptions developed considerable expansion. Bodies with low absorptions composed of pure clay and feldspar developed practically no moisture expansion while those composed of clay, feldspar, and more than 20% silica developed considerable moisture expansion. By adding magnesite, the resistance of a ceramic body to moisture expansion was improved. Additions of whiting, iron oxide, and titanium oxide were not as beneficial as magnesite. It was found that crazing caused by moisture expansion of bodies can usually be prevented by proper manufacturing control.
THE PACKING OF PARTICLES1
Authors: Westman A. E. R. , Hugill H. R.
Published: June 2006

It is axiomatic that the mode of packing of very large volumes of particles of uniform shape and size is independent of the size of the particles, provided they are large enough for the effect of electrostatic forces, air films, etc., to be negligible. An apparatus is described, in which equal true volumes of approximately spherical particles, ranging in diameter from 0.2 to 0.0035 inch, pack practically to the same apparent volume. This apparatus was used in studying the packing of mixtures of two and three sues of particles. By plotting the data so obtained in diagrams of a particularly convenient character, it is shown that the apparent volumes of mixtures containing unit real volume of solid fall between limiting values which can be calculated from simple assumptions, and that their deviation from these limits depends in a definite manner upon the diameter ratios of the component particles. The conditions governing the application of the results of the study to ceramic technology are pointed out.
THE CAUSE AND PREVENTION OF CERTAIN BROWN STAINS ON SEMIVITREOUS TABLEWARE1
Authors: Loomis G. A.
Published: June 2006

It has been found that the brown stains formed on ware bedded in sand in the bisque fire are due to a reduction of iron in the sand. This reduction is apparently due to insufficient air in the saggers during oxidation of the ware when the kiln atmosphere is low in excess air. Firing the ware in saggers with holes to allow a circulation of air prevented the stains. The ware may also be fired in closed saggers without these defects by admitting sufficient excess air to the kiln and allowing more time at low oxidation temperatures.
SOME OPERATING PROBLEMS IN CLAY MINING1
Authors: Nold H. E.
Published: June 2006

Actual problems, the cause and possible solution are described. Calculations are given showing the economies of good drainage, well upkept equipment, and sane management of clay mines. Observations show that clay is wasted and mining hazardous and unnecessarily expensive in several of the clay mines examined. Recommendations are made.
A NEW FORM OF NONPLASTIC MATERIAL1
Authors: Fesslbr A. H.
Published: June 2006

This article indicates the results obtained by introducing into a porcelain mixture an unstable nonplastic aggregate, consisting chemically of alumina, silica, and a fluxing oxide, which latter has been heat‐treated in such a manner that its crystallization has been arrested. Upon subsequent kiln Wing, crystallization takes place and the arrested crystals grow, orienting themselves in such a manner as to form a network of interwoven crystals. The effect of this crystallization improves the physical properties of the porcelain.
AN IMPROVED MERCURY VOLUMETER1
Authors: MCMAHON J. F.
Published: June 2006

This paper discusses several mechanical improvements on the Goodner mercury volumeter, which include a counter‐balance for the burette, an automatic light system, and a plunging device. The construction, operation, and advantages of the plunging device are discussed. The advantages of the mechanism are (1) no string or string marks, (2) cleaner mercury, (3) no bulky weight to be deftly handled, (4) less handling of briquets, and (5) more ease and speed in operation.
METHOD OF COMPARING THE VISCOSITIES OF PORCELAIN BODIES1
Authors: Parmblee C. W. , Badger A. E.
Published: June 2006

A torsional method is described and some results given of the study of the viscosity of porcelain in the temperature range 700 to 800°C.
COST SAVINGS IN CONTINUOUS FURNACES1
Authors: Dutton C. A.
Published: June 2006

The continuous furnace is replacing the box‐type furnace because of its savings in labor, fuel, and floor space, its indirect savings in quality, production, and cost control, as well as its simplified supervision. It has also made further savings possible by the application of the continuous principle to other enamel shop operations, continuous spraying, for example.
A STUDY OF THE CONSISTENCIES OF RAW TERRA COTTA GLAZES1
Authors: Fetterolf L. D.
Published: June 2006

For measuring consistencies of glazes, a method was used based on the conception of glazes as plastic materials. A normal glaze thinned during the entire period of testing, being attended by a large decrease in yield value and a moderate increase in mobility. Use of an aged clay slip as a source of clay did not change the plastic properties or aging characteristics of the glaze. Heating a freshly milled glaze resulted in a consistency comparable with that developed by aging a normal glaze for a month. Water solubilities of glaze materials were determined as well as character and concentrations of soluble salts in mill liquors and PH values of mill liquors. Solution of salts was progressive over a period of time and increasing alkalinity was probably the cause of spontaneous thinning. Gum arabic in proper amount was found to stabilize glaze consistency satisfactorily. Effects of acid, alkali, and water additions to gum‐bearing and gumless glazes were studied.
THE ADAPTABILITY OF VARIOUS METHODS TO THE COLOR‐ DETERMINATION OF WHITEWARE BODIES1
Authors: Meyer William W.
Published: June 2006

A reliable and convenient instrument is needed to measure the absolute color of nearly white ceramic bodies. Various instruments and methods for color measurement are here described and criticized. Nearly all of them neglect the importance of the source of illumination. A method of color measurement is given, and although the Klett‐Ritchic spectro‐colorimeter was found to be unsatisfactory for this work, it is believed that the modification of the Pfund colorimeter suggested here would be a reliable and conveuient instrument for plant use.