bluuebunny/crossref_metadata_2025 huggingface dataset:
THE USE OF THE AUTOCLAVE IN TESTING CERAMIC PRODUCTS FOR RESISTANCE TO CRAZING1
Authors: Mills R. G.
Published: June 2006

A report is presented of preliminary tests in an investigation to determine the effects of various factors in the manipulation of the autoclave for testing wall tile. The effect of porosity. pressure, duration of test, slow versus rapid release of pressure, and the number of repetitions of the test have been investigated.
IMPACT PROPERTIES OF CHINA1
Authors: Scaramm Edward , Hall F. P.
Published: June 2006

The relation of impact tests on tableware to impact properties as determined on small test pieces, breaking with transverse, shearing, and compression blows are discussed. Data are given for compression impact covering the field of china bodies. The relation of impact resistance to the elastic properties of bodies is also discussed.
COST OF FELDSPAR1
Authors: Amberg C. R.
Published: June 2006

A discussion of the use and value of the classification of feldspars as proposed by the Feldspar Grinders' Institute is taken up and another classification based on the pounds of fluxing oxodes per ton is proposed.
GROUND CLAY AS A PLASTICIZING AGENT1
Authors: Spangler M. G.
Published: June 2006

A series of tests to determine the relative tensile strength of mortars containing hydrated lime and finely‐ground raw clay used as plasticizing agents have been conducted. These tests reveal no distinct ditrerence between the two materials in this respect.
THE CORROSION OF TANK BLOCKS BY OPAL GLASSES1
Authors: Uhrmann C. J. , Slater S. M.
Published: June 2006

The manufacture of opal glass in day tanks has made it necessary to study the corrosion of tank blocks. Opacifiers have to be used in larger quantities than in batches for opal glasses melted in covered pots because of the loss of density due to higher melting temperatures and shorter melting times, and exposure of batch to reactions from the direct flame heat.

Experiments have been conducted to ascertain the factors which will allow the use of the lowest amount of opacifiers, the shortest practical melting time with the highest practical melting temperature, and also to minimize the corrosion of the bottom blocks of tanks by application of a cooling system, as well as prevention of separation of batch by practising certain “filling‐in” methods of the batch, and as a final result to reduce block stones in the glass. The experiments have resulted in the successful operation of day tanks for opal glass and in prolonging the life of the tanks, and have made possible the manufacture of thin blown dense opal glasses of almost as good quality from tanks as can be produced in pots.
OBSERVATION ON THE EFFECT OF SILICON CARBIDE IN CLAY BODIES1
Authors: Walton S. F. , Hauman E. L.
Published: June 2006

In these studies the distinction is made between silicon carbide in a clay body and clay‐bonded silicon carbide. An increase of strength by replacement of grog particles was noted. Tests were made on various bodies containing as little as 10% Sic by weight and up to 67% by weight. Comparison of clay and grog bodies, clay grog, and SiC bodies, and clay and SiC bodies were carried out under the load‐span test at various temperatures.

The resistance of bodies containing SiC to the corrosion effect of various slags, particularly iron oxides with alkalis and alkaline earths, is given. A comparison is made with clay‐grog bodies. The increase of conductivity of bodies containing SiC is apparent. Commercial application of SiC and clay bodies is discussed.
ADVANTAGES AND USE OF A CO2 METER ON A FORCED DOWNDRAFT PERIODIC KILN AS TO TEMPERATURE DISTRIBUTION1
Authors: McCann D. M.
Published: June 2006

Notes on forced downdraft system used on dry‐pressed electrical porcelain fired to cone 12 flat are discussed. The type and general construction of the kiln, heat distribution, fuel used per firing, and the use of the CO2 meter for adjusting the draft for various conditions to get uniformly fired kilns, both as to time of firing and appearance of ware, are given.
SOME RESULTS OBTAINED THROUGH THE USE OF BORAX IN THE MANUFACTURE OF TANK GLASSES1
Authors: Schurtz D. D.
Published: June 2006

In the manufacture of various types of tank glasses, the introduction of a moderate amount of borax is becoming the general practice. Increased furnace production, less checking in fabrication, better finish, and more durable ware are indicative of its use. The introduction of borax and some of the problems connected with it are discussed.
ACTION OF THE DUST FROM THE BATCH ON THE CHECKER BRICK OF GLASS FURNACE REGENERATORS1
Authors: Beliankin D. S. , Besborodov M. A.
Published: June 2006

The crusts and glazed slag formations due to the glass batch dust that is carried by the gas current beyond the pots into the regenerators, flues, and burners were examined microscopically by X‐ray and chemical analysis. Crystals of nepheline, car‐ negieite, and mullite are noted. This paper deals with the crusts and glazed surfaces in the regenerating chambers of two different pot furnaces.
THE INTERPRETATION OF PLANT AND LABORATORY TEST DATA1
Authors: Fbrguson Kohbrt F.
Published: June 2006

Plant and laboratory test data may often yield more information if modern statistical methods are applied to them.Some of the more elementary concepts are defined and their method of application illustrated. The paper is intended to introduce the subject to those who have not yet studied it.
THE PHYSICAL PROPERTIES OF THE FINENESS FRACTIONS OF SLAKED SEMIFLINT CLAY1
Authors: Holmes M. E. , Paul A. J.
Published: June 2006

A select sample of Missouri semiflint clay was slaked to its natural size of grain and screened into the following sizes: on 20, 20 to 40, 40 to 60, 60 to 100, and through 100‐mesh.

The 100‐mesh fraction is a very dense firing clay, giving a high dry and fired modulus of rupture, and would be effective as a “dope” for a weak clay. The properties of the intermediate finenesses are substantially an average of the properties of all the finenesses. Points of inferiority in the coarse fractions are supplemented by points of superiority in the fine fractions, and vice versa. All fractions are therefore desirable, and further, there are indications that no substantial improvement could be made by screening out any one of the fractions.
THE EFFECTS OF ADDITIONS OF ZINC OXIDE AND CADMIUM OXIDE ON SIMPLE GLASSES1
Authors: Parmelee C. W. , Ehman R. G.
Published: June 2006

The glass consisted of the composition SiO2 58%, PbO 22%, and Na2O 20%. Zinc oxide was introduced in increments of 5% up to a maximum of 20% as a substitute for equivalent parts of Na2O. Similar substitutions were made with cadmium oxide. The following physical properties were studied: thermal expansions, solubilities in hydrochloric acid, indices of refraction, and annealing conduct. Analyses of the glasses were made. The suitability of these glasses as vitreous enamels is discussed. A vacuum electric furnace for melting and fining glass under reduced pressures is described.
DESIGN FOR ENAMEL SMELTING FURNACE1
Authors: Cooke R. D.
Published: June 2006

Experiments with the construction of an open‐heart smelter are described which resulted in the design as described. The walls were made thin and the bottom supported on beams which exposed the entire outside of the heart to the air.
A STUDY OF SOLUBLE SALTS IN ENAMELS1
Authors: Cooke R. D.
Published: June 2006

A study was made of the effects of a number of soluble salts on one type of sheet‐steel enamel. The factors affecting the quantities and nature of the salts normally appearing in the enamel water were observed. The effects of these salts together with those of a number of added salts were noted from the standpoint of set‐up of the enamel, rusting of the iron, and appearance of the fired enamel.
THE USE OF THE LINDEMANN‐DANIELSON CROSS‐BENDING TEST MACHINE1
Authors: Kinzie C. J. , Plunkett J. A.
Published: June 2006

The effect of several variables such as enamel type, thickness of coating, fineness of milling, etc., are discussed and results are submitted. A special application of this machine is described in which it has been used in studies on the effect of dry film strength upon tearing in vitreous enamels.
PEBBLE MILL LININGS1
Authors: Twells Robert
Published: June 2006

Pebble mill linings used in the ceramic industries consist chiefly of flint, quartzite, and porcelain blocks. Rubber linings have had considerable attention recently. The advantages and disadvantages of each type are discussed. Data are given showing relative costs at the Champion Porcelain Company of Belgian flint, “sillimanite” spark plug porcelain, and one‐piece rubber linings. Of the first two, the porcelain showed the lowest cost per year of service. The test of the rubber lining is not complete, but its high initial cost practically eliminates it on that basis. For special purposes the additional cost of the rubber lining might be justified.
A SMALL GAS‐FIRED LABORATORY FURNACE1
Authors: Norton F. H. , Norton C. L.
Published: June 2006

There is described a small furnace, particularly suitable for experimental work in ceramics. This furnace is unique in that temperatures sufficiently high for nearly all operations in ceramics can be obtained by the use of a standard Méker burner. The temperature can be brought up rapidly and can be held steadily. The construction of the furnace makes it comparatively simple and inexpensive.
THE INFLUENCE OF CHEMICAL COMPOSITION ON THE PHYSICAL PROPERTIES OF GLAZES*
Authors: Hall F. P.
Published: June 2006

This paper presents some preliminary work on the study of the factors affecting fit of ceramic bodies and glazes. From the experimental work on 118 glazes and glasses, a method is outlined for calculating from the chemical composition of the glaze, approximate values of the tensile strength, Young's modulus of elasticity, and the mean linear coefficient of expansion of the glaze in the temperature range from 25°C to the lower limit of the critical range.
PHASE EQUILIBRIA IN THE SYSTEM SiO2–ZnO1
Authors: Bunting E. N.
Published: June 2006

A study of phase equilibria in the condensed system SiO2–ZnO by the quenching method shows the existence of (a) only one compound, Zn2SiO4, the mclting point of which is 1512°C; (b) a region of two immiscible liquid phases in equilibrium with cristobalite at 1695°C, extending from 2 to 35 mol. per cent ZnO; (c) a euiectic between tridymite and Zn2SiO4 at 1432°C and 49.1 mol. per cent ZnO; (d) a eutectic between ZnO and Zn2SiO4 at 1507°C and 77.5 mol. per ceut ZnO. The mclting point of Zno is found to be 1975°± 25°C.

An irdium vessel is described which can be used in an induction furnace to obtain constant temperatures up to 2300°C in an oxidizing atmosphere.
BONUS METHODS OF WAGE PAYMENT AS RELATED TO PRODUCTION1
Authors: Straight H. R.
Published: June 2006

The factors entering into the set‐up of a bonus system designed to increase production together with lower costs, decrease in labor turnover, and maintaining the quality up to standard are discussed.
RAW AND WHITE GROUND COAT1
Authors: Malinovszky A.
Published: June 2006

The author discusses the possibility of using the mineral lepidolite as a ground coat or enamel. The analyses of several samples of lepidolite are given; their refractoriness and expansion values are also calculated. Being high in Al2O3 and containing no B2O3 precludes the use of lepidolite in any essential quantities. Lithium oxide of which lepidolite contains about 4% does not aid in adhesion of the ground coat to cast iron. The patented ground coats with their various materials and minerals are discussed. The literature is reviewed and examples of good and defective ground coats are named using composition data and microphotographs to illustrate the essentials for good ground coat adherence.
IMPURITIES IN COMMERCIAL FELDSPARS OFTEN OVER‐LOOKED BY ENAMELERS1
Authors: Crandall James R.
Published: June 2006

The author points out the necessity for careful selection and constant supervision of all raw materials, together with simple tests which the enameler may apply to such materials to insure a uniform product free from objectionable impurities.
COMMERCIAL FELDSPARS PRODUCED IN THE UNITED STATES1
Authors: Knight F. P.
Published: June 2006

An impartial survey of the various commercial feldspars available is presented to the consumers of that product. Discussions and analyses of many of the commercial feldspars mined in the United States and Canada and analyses of actual shipments are given. The similarities and differences between feldspars of the different sections and the quality and fineness of grinding in connection with the branches of the ceramic industry using feldspar are discussed. Blending of feldspars is also considered.
CLAY SEWERPIPE MANUFACTURE1
Authors: Blessing Robert L.
Published: June 2006

This paper continues the description3 of the methods employed in a survey of sewerpipe kilns.

Data and curves are given to indicate the rates of moisture removal during the normal watersmoking period and at higher temperatures. The information obtained reveals conditions that cause both continuous and non‐continuous losses; it is, therefore, difficult to judge the end of the watersmoking period by loss‐of‐weight methods. The applications of the findings to making heat‐balance determinations and to correct kiln manipulation are considered. The discussion covers also the variation and significance of moisture in ware, a possible explanation of weight loss at temperatures above watersmoking, and the danger of using fast rates in this range.
CLAY SEWERPIPE MANUFACTURE1
Authors: Arnold R. E.
Published: June 2006

This paper describes an inexpensive, simple, and satisfactory method for multiple kiln installations to correct for cold‐junction temperature variations.
THE STRENGTH OF GLASS AS AFFECTED BY CASING1
Authors: Bailey James
Published: June 2006

Considerable regarding the strengthening of glass by surface chilling has been written. Theoretically it has been shown that the modulus of rupture of slabs toughened glass may have a maximum of 3.4 times that of annealed glass. Complicated shapes and large surfaces cannot be satisfactorily treated by this method.

Very similar results may be obtained by the method commonly called “casing,” wherein the article consists of three layers, the two outer ones being of glass having a lower coefficient of expansion than the inner layer.

After annealing in the usual way the outer layers are left in compression and the central layer is in tension. By combining these initial stresses with those set up during a test to determine the modulus of rupture, a set of equations was derived. These equations were expressed in graph form, one of which gave the relation of case thickness expressed in tenths of the total thickness to the relative strength compared to flawless annealed glass. A number of curves were shown based upon the ratio of maximum internal tension to the maximum tension at the surface. These curves enabled the proper case thickness to be found in order to develop optimum strength for any assumed ratio of maximum internal tension to external tension.

Another graph showed the corresponding initial tension and compression due to casing for the conditions outlined above. These curves showed that the case thickness could vary considerably without greatly affecting the strength and also that the initial stresses are smaller than those usually thought necessary.

The maximum relative strength as developed by “casing” had a somewhat smaller value than that developed by “toughening.”
AN APPARATUS FOR DETERMINING THE ANNEALING CONSTANTS OF GLASS1
Authors: Sharp Donald E. , Bailey James , Hyman Irving
Published: June 2006

An apparatus is described by means of which annealing data on glass may be rapidly and accurately obtained. Essentially, the apparatus consists of a mechanical means straining the glass, an optical means of measuring the stresses, and a means of heating the sample uniformly while making the measurement. The results are consistent and expressed in definite terms. The specimens for test may be quite small. The apparatus may be used for control purposes in place of measuring softening temperatures.
STUDIES ON THE ETCHING OF GLASS1
Authors: Kahlson W. S.
Published: June 2006

This paper discusses the factors governing the reaction silica‐fluorine. The chemical nature of the reactions involved in the etching of glass are described in detail in conjunction with a crystallographic analysis. The behavior of etching solution toward glasses of varying composition is described.
MANUFACTURE OF THIN PORCELAIN PARTS OF CLOSE DIMENSIONAL TOLERANCES1
Authors: Shaw L. I. , Johnson A. G. , Scott W. J.
Published: June 2006

A method for manufacturing a porcelain washer 0.030 inch thick and 0.495 inch ± 0.003 inch inside diameter is described. Strength sufficient to allow the handling and trimming of the raw parts is secured by using waxes as the temporary binder of the dry ceramic materials, and forming under higher pressure. As the plasticity necessary for forming is obtained with wax, the stresses and resulting deformation incident to the use of clay plasticized with water are eliminated. Lower, more uniform shrinkage with resultant closer dimensional control is thus obtained.
A STUDY OF THE EFFECT OF GROG ON PRESSURE TRANSMISSION IN DRY PRESSING1
Authors: Dodd By C. M. , Holmes M. E.
Published: June 2006

A study of the dry‐pressing characteristics of several fire brick and building brick clays was made by compressing them, at high and low pressures, into large shapes with a hydraulic press The clays do not effectively transmit the pressure into the interior. The finest grained clays are morc deficient in this respect. The result is a porosity gradient as high as 15% of the interior porosity between center and surface. Such a variation may account, in part, for the defects in dry‐press ware. The addition of fired grog increases the pressure transmission. Some clays require more than 50% grog and some less for maximum pressure transmission and optimum results. Fireclay shapes as much as ten inches in thickness and of substantially uniform physical properties can be formed if the proper amount of grog is used.
THERMAL SHOCK EFFECT ON THE TRANSVERSE STRENGTH OF CLAY BODIES1
Authors: Morgan W. R.
Published: June 2006

Test specimens of twenty commercial shale and fireclay bodies, ranging in softening point from cones 7 to 30, were fired in laboratory kilns to cones 04, 2, and 6. Comparisons of transverse strength before and after thermal shock were made, thermal shock h a i h g been produced by eight cycles of heating in a furnace at 1100°F for 15 minutes and cooling over an air blast for an equal length of time.

Results indicate that as initial strength increases, per cent reduction in strength increases and strength after thermal shock increases to a maximum and then declines. Curves are fitted to the data and the mathematical relationships are shown.

The results of other investigators are discussed.
COMPARISON OF BODIES CONTAINING BLENDED FELDSPARS AND ONE‐MINE FELDSPAR OF SIMILAR COMPOSITION1
Authors: Parmelee C. W. , Amberg C. R.
Published: June 2006

An electrical porcelain body mixture was prepared in several batches, each of which contained a different feldspar. These several bodies were formed by hand pressing, extrusion, and casting. After they had been fired a comparison was made of the volume changes and bulk specific gravities.
MOISTURE EXPANSION OF GLAZES AND OTHER CERAMIC FINISHES1
Authors: Schtjrecht H. G. , Polb G. R.
Published: June 2006

Research for ascertaining why some glazes are more resistant to “moisture crazing” than others revealed the fact that certain glazes expand, because of the action of water, similarly to some of the ceramic bodies t o which they are applied. Although a control of this type of expansion is very important in fitting glazes to bodies, it has not been previously considered. Its importance should be evident at once when it is considered that a large “moisture expansion” in a glaze or other finish is in many cases an indication that the glaze will not be so liable to craze when the ceramic ware or material on which it is used is exposed to moisture. This follows since the glaze and the body on which it goes and which is ordinarily very susceptible to this kind of expansion will then increase in size simultaneously and more nearly at the same rate. Such conditions lessen the tendency of the body expansion to cause tensile stresses in the glaze.

In this investigation specimens of various finishes were subjected to steam at 150 pounds per square inch for an hour because it was known that this treatment of such materials produces effects similar to those caused by long exposure to weather. This artificial weathering treatment caused in lustrous glazes an average expansion of 0.004%, in mat glazes 0.011%, in vitreous slip finishes 0.005%, and in porous slip finishes 0.033%. The moisture expansion of one of the mat glazes was 30% of the average obtained for a ceramic body having an absorption of approximately 12%. This proclivity of ceramic finishes to expand by the absorption of moisture can be controlled in their manufacture.
THE PROPAGATION OF FISSURES IN GLASS AND OTHER BODIES WITH SPECIAL REFERENCE TO THE SPLIT‐WAVE FRONT1
Authors: PRESTON F. W.
Published: June 2006

This paper pursues the conclusion, reached in earlier papers2 that the details of glass fissures can be explained on the basis that the head of an advancing fissure cndeavors at all times to stay at right angles to the principal tension in its immediate neighborhood. This argument is followed here into some of its more complex manifestations, particularly into the complications of fissure‐form that arise when the fissure‐front splits, giving rise to hackle‐texture and “stries” (“feather‐patterns”) on the one hand and to radiant formation on the other.
STRESSES IN WIRE GLASS DUE TO THE WIRE1
Authors: PRESTON F. W.
Published: June 2006

Since the polariscopic evidence as to the strains in wire glass caused by the wire is either absent or hard to interpret, this paper was originally a mathematical investigation as to what strains there ought to be, and what they ought to look like in the polariscope. In the present pages, however, the findings are presented first in nonmathematical form, and the mathematical skeleton is secreted in a cupboard or appendix. The findings arc checked with the polariscopic evidence, and a number of interesting points are, it is believed, here presented for the first time.
REINFORCED BRICK MASONRY1
Authors: Lent Major L. B.
Published: June 2006

A descriptive presentation of the practical use of reinforced brick masonry is given together with a historical survey of the development of its use.
EFFECTS OF BODY COMPOSITION AND FIRING TREATMENT ON SALT GLAZES1
Authors: Hufsh R. K. , Clemens E. C.
Published: June 2006

Five synthetic bodies were made up in which the silica, alumina, ferric oxide, and alkalis were varied. Salts were added to these bodies in various amounts; the bodies were dried and fired under carefully controlled conditions and salt glazed under oxidizing conditions at cones 2, 5, and 7 and under reducing conditions at cone 5. The effects of body composition and glazing temperature on the appearance of the bodies are giveu. Reducing conditions during glazing increased the glaze thickness. The maturity of the glaze is more important than the thickness. Devitrification of the glazes is more important than the presence of impurities. Crystals of hematite, acmite, nephelite, and carnegieite were found in the glazes. Firing treatment has a greater influence on glaze character than chemical composition.
SODIUM SILICATE, A NEW ENAMEL RAW MATERIAL1
Authors: Manson M. E.
Published: June 2006

The addition of silica to enamel in the form of a readily fusible silicate, such as sodium silicate, lowers the smelting time and temperature required to bring about complete solution of the silica. Enamels in which all the silica was introduced in the form of quartz, although apparently completely smelted, still contained large quantities of free silica, while enamels of identical analysis in which sodium silicate was the sole source of silica contained, after smelting, no free silica. The presence of this free silica in an enamel affects its workability and acid resistance.
DESIGN AND CONSTRUCTION OF POLARISCOPES FOR USE IN GLASS FACTORIES1
Authors: Spencer C. D. , Jones Shannon
Published: June 2006

This paper presents the most important considerations in the design and construction of polariscopes for routine factory use as found in the author's experience. A short summary of the various methods of obtaining plane‐polarized light is given in which preference is given to the reflection method for this type of instrument. The use of binocular analyzers, together with the importance of the matching of the field colors due to the tint‐plates, is pointed out.
A LABORATORY EQUIPMENT FOR STIFF‐MUD TESTS, INCLUDING EXHAUSTION OF THE AIR1
Authors: Lovejoy Ellis , CoVan H. E.
Published: June 2006

A small auger machine is described for laboratory use in testing stiff‐mud clays with special reference to de‐airing the clays and for investigation of augers, dies, and various devices which affect the flow of stiff‐mud clay.
APPLICATION OF THE DOWNDRAFT PRINCIPLE TO TUNNEL KILNS1
Authors: Richardson W. D.
Published: June 2006

Down draft is established as best for producing even heat distribution in periodic and chamber kilns. Methods of applying down draft to tunnel kilns are described and illustrated.
A GRAPHICAL REPRESENTATION OF THE MOLECULAR FORMULAS OF CERAMIC GLAZES1
Authors: Holscher H. H. , Watts Arthur S.
Published: June 2006

A chart representing average glaze composition, including lead, fritted, Bristol, and porcelain glazes, as plotted against temperature is presented as a means for teaching glaze compositions and for getting a broad view of the constituents of glazes and their variation with temperature. The chart covers the range from cones 015 to 18.
THE HEAT BALANCES OF SOME CERAMIC KILNS*
Authors: Mansur Howard H.
Published: June 2006

The instruments, methods, and procedure for obtaining the data, the method for calculating heat balances, the description of the kilns and ware, and the efficiencies of the kilns, six in number, are given in detail. Two round downdraft kilns, one muffle, one rectangular horizontal draft, one semicontinuous, and one wholly continuous kiln were investigated. A bibliography is appended.
ORGANIC COMPOUNDS AS ELECTROLYTES AND THEIR EFFECT ON THE PROPERTIES OF CLAY SLIP AND ON THE LIFE OF PLASTER MOLDS1
Authors: Parmelree C. W. , Harman C. G.
Published: June 2006

An attempt was made to indicate the possibility of using organic compounds as casting electrolytes, and to ascertain their effect upon the durability of plaster molds. The data presented point out the fact that ethylamine, piperidine, or tetramethylammoniumhydroxide may be used as casting electrolytes and that they attack molds to a lesser degree than do sodium carbonate and sodium silicate.

Some data are presented which compare viscosity with surface tension.
CONSTRUCTION OF REFRIGERATOR LININGS1
Authors: Wolff C. H.
Published: June 2006

During cooling, compression tests were built up in the enamel coating while the iron itself was under tensile strain. The compression forces from the three sides met at right angles at the corners of the linings and caused chipping Mechanically reënforcing these corners helped little. By notching the flanges, welding in small fillet, and welding an angle strip underneath the flange at the corner, the forces at work were reduced enough to overcome the chipping.
THE ELECTRICAL DEWATERING OF CLAY SUSPENSIONS1
Authors: Curtis Carl E.
Published: June 2006

The history of the developments by Count Schwerin, application at Carlsbad with detailed description of the plant, and review of the investigations of others on dewatering of clays by electrophoresis, are given at length. The investigations by the author, including a description of the apparatus, materials, voltage, and electrolytes are described with a statement of the results obtained with variations of each factor. The possible efficiency as a clay dewatering means is discussed. Plasticity theories are discussed in the light of the evidence obtained. The power cost is from 65 to 80 cents per ton of clay. On the average, clay dewatering by electrophoresis is no more efficient than the filter‐press, but it has shown greater efficiency on very fine‐grained clays. Bibliographies are appended on (1) colloids in clays, (2) theories applying to electro‐endosmosis, (3) electromosis, and (4) Schwerin's patents. A short biographical sketch of Count Schwerin is also appended.
A PORTABLE PYROMETRIC CONE EQUIVALENT FURNACE1
Authors: Cartwright Vance , Phelps Stuart M.
Published: June 2006

A description is given of the development of a portable P.C.E. furnace that can Le operated on natural gas or propane which can bc purchased in tanks. The A.S.T.M. rate of heating is easily maintained and cone 38 can be brought down. The cost per run to cone 34 when using compressed gas is less than $1.00, while with natural gas the cost is about one‐tenth as much.
THE INFLUENCE OF CHEMICAL COMPOSITIONS ON THE PHYSICAL PROPERTIES OF SODA‐LIME GLASSES1
Authors: Gill J. W. , Rueckel W. C.
Published: June 2006

Nineteen soda‐lime glasses covering the commercial field were prepared, melted, and fined for 2 hours. The chemical composition of the raw materials was determined by usual analytical methods; the refractive index was determined by an Abbé refractometer; density, by the normal suspension method; and softening point, by the Littleton method with the furnace as specified in Jour. Amer. Ceram. Soc., 10 [4], 259‐63 (1927).

The data indicate the following points: (1) When the silica was kept constant by increasing the dolomitic lime at the expense of soda an increase in softening point of 11 to 12°C per 1% increase was obtained. Likewise the density increases 0.004 and the refractive index 0.0015 per 1% increase of lime. (2) When the soda was kept constant the softening point was practically constant. The density decreases 0.011 and the refractive index 0.0030 per 1% increase of silica at the expense of lime. (3) When the lime was kept constant the increase in softening point per 1% increase in silica varied as follows : 5% lime 21°C, 8% lime 17°C, 10% lime 15°C, and 12% lime 12°C. The density decreased 0.008 and the refractive index 0.0015 per 1% increase in silica at the expense of soda. (4) A thermo‐chemical relation of the softening points and the chemical compositions (calculated) closely paralleling the “liquidus” surfaces of Feild and Roysters' system: CaO‐Na2O‐SiO2.
DEGASSING CLAYS BEFORE MOLDING1
Authors: Straight H. R. , Cowman M. G.
Published: June 2006

The value of a degassing rotary soak table is shown in decreased laminations and greater adhesion of the clay grains. The clay must be ground sufficiently fine to degas the particles quickly.
A COMPARATIVE STUDY SHOWING THE POSSIBILITIES OF SILLIMANITE FOR USE IN EXTRUSION DIES1
Authors: Dager P. W. , Betteley A. G.
Published: June 2006

This article sets forth the results obtained on the use of sillimanite for extrusion dies. A comparison of the relative length of life of various metal dies and sillimanite dies shows that sillimanite is very resistant to abrasion and has possibilities for use in dies.
NOTES ON DRYING AND DRIER OPERATION1
Authors: Robson James T.
Published: June 2006

A brief résumé is given, comparing drying shrinkage with the action of clay slaking in a bank. The drying of Missouri dry‐press refractories in summer versus winter and blistering and mcans of prevention are discussed. The operation of three Harrop type driers and an ordinary waste‐heat tunnel drier are described.
SOLUTION OF THE MODULUS OF RUPTURE EQUATION BY MEANS OF A SIMPLE FOUR‐VARIABLE CHART1
Authors: Mills R. G.
Published: June 2006

A form of nomographic chart for the solution of the modulus of rupture equation is described. The chart is direct reading and less time is required for the determination from experimental data than with most methods.
THE MELTING RELATIONS OF POTASH FELDSPAR, SODA FELDSPAR, AND FLINT MIXTURES1
Authors: Amberg C R. , Gallup J. L.
Published: June 2006

P.C.E. values of ternary mixtures of potash feldspar, soda feldspar, and flint were determined and results shown on a solid phase diagram. No eutectics were developed with either of the binary series of feldspar and flint. The soda feldspar‐flint mixtures were more refractory than were those of the potash feldspar series. At least 20% flint variation with potash feldspar will show no change in P.C.E. values and at least 10% with the soda feldspar showing the unreliability of P.C.E. to indicate the amount of the quartz content.
COLEMANITE AS GLAZE MATERIAL1
Authors: French Myrtle Meritt
Published: June 2006

Experiments were made to find a natural frit which would replace lead and eliminate fritting. Colemanite supplemented by kryolith was found satisfactory, at least at certain temperatures.
PROPERTIES OF SOME NORTH DAKOTA BENTONITES1
Authors: Hammers Freida L. , Budge W. E.
Published: June 2006

Seven samples of North Dakota bentonites were studied. In general, properties of the raw, fired, and acid‐treated samples are compared with those of bentonites rrported from other districts. The deposits are described briefly.
OBSERVATIONS ON CRAZING IN TERRA COTTA GLAZES1
Authors: Planje C. W.
Published: June 2006

Theories and observations for the prevention of crazing in a leaded fritted lustrous glaze are given. The use of various raw materials and their effect upon a glaze with respect to crazing are discussed and several recommendations are made.
OVERGLAZE POLYCHROME CONE NO. 61
Authors: Strusholm A. M.
Published: June 2006

The colors and glaze described enable the operator to paint figures, landscapes, or any decorations desired over an unfired glaze sprayed over a flat surface. Not having the ornament modeled in bas‐relief, the ware can be fired with the regular terra cotta to cone 6.

The body glaze can be sprayed over a terra cotta body having 35% calcined grit added. If a more sandy body is used, less silica should be added to the glaze to counter‐act crazing.
RESEARCHES IN DRY‐PRESS REFRACTORIES, III. THE EFFECT OF VACUUM ON THE UNFIRED PROPERTIES OF SOME DRY‐PRESS REFRACTORY BATCHES1
Authors: Rueckel W. C.
Published: June 2006

A series of tests on several typical refractory bodies are presented. These include data showing the effect of varying the amount of vacuum, and its length of time of application on the green and dry properties. The limits of pressure attainable with a mechanical press are also discussed.
MECHANICS OF ENAMEL ADHERENCE, I
Authors: Lord J. O. , Rueckel W. C.
Published: June 2006

The customary method for preparation of metallographic specimens is described, with modifications necessary to adapt the method to preparation of sections of enameled metal. The modifications noted are (1) cutting the section at an angle to the plane of the sheet so as to expose a wider band of enamel and metal, (2) maintaining the direction of grinding and polishing so that the action is from enamel to metal portions of the surface a t all times, and (3) using a paraffin covered wheel with levigated alumina as a polishing medium, in order to secure a flat surface.

The use of the metallographic microscope in the examination of these specimens is described with some conclusions regarding the false appearances of lincs of contact, etc., due to improperly prepared specimens.
ACID‐RESISTING, DRY‐PROCESS, CAST‐IRON ENAMELS, AND THE EFFECTS OF BaO, PbO, AND ZnO1
Authors: Frtterolp L. D.
Published: June 2006

An enamel composition to which any workable enamel of this type must quite closely conform is given. Eighty‐six per cent of the enamel composition must be held within definite proportions. The function of each of these constituents and the percentage required are discussed. The remaining 14% of the enamel may be supplied by combinations of BaO, PbO, and ZnO, with some latitude in proportions permissible. Results of a careful study of the influence of each on smelting properties, acid resistance, fusibility, covering power, color, and brightness are presented.
RELATION OF COEFFICIENT OF EXPANSION TO CROSS‐BENDING STRENGTH OF SHEET‐STEEL ENAMELS1
Authors: Gautsch Murray C.
Published: June 2006

Two series of enamels were made with calculated cubical coefficients of expansion varying from 361 to 306. In both series of enamels, the cross‐bending values were inversely proportional to the coefficient of expansion. This is due to the fact that all enamels on sheet steel have lower coefficients of thermal expansion than steel. In cooling, after the enamel is fused to the metal, strains are set up in the enamel; the lower the expansion of the enamel the greater the strains. When the enameled piece is bent, the greater the stresses present, the farther the pieces can be bent before there is any real tensile strain on the enamel. High bending ability is dependent primarily on high compressive strains induced by lower coefficient of expansion of the enamel than of the metal base. Compressive strains cause warping, fishscaling (in ground coat), and chipping; therefore the bending strength should not be too high. In all control work both the minimum and the maximum bending strength should be specified.
AUXILIARY FLUXES IN CERAMIC BODIES1
Authors: Collins Paul F.
Published: June 2006

Twenty‐five synthetic fluxes composed of ceramic materials, compounded in their eutectic proportions and fused to clear glasses, were added to a body of the semivitreous type in varying amounts, and their effect on vitrification was studied. It has been found possible to reduce the feldspar content of such a body to 8% and, by an addition of 2% of auxiliary glass, to develop almost any desired degree of body vitrification between 0.5 and 7.0% at a temperature as low as cone 6.
A CONE NINE VITRIFIED FLOOR TILE BODY1
Authors: Kirkpatrick F. A. , Williams W. E.
Published: June 2006

A group of twenty‐eight floor tile bodies in a triaxial field was studied experimentally for the purpose of developing a vitrified, non‐staining tile at cone 9.
SIMPLIFICATION OF THE RING METHOD FOR DETERMINING GLAZE STRESSES1
Authors: Davis H. E. , Lueders R. L.
Published: June 2006

This work was undertaken to develop a ring for the determination of glaze stresses which would show movements great enough to be measured with a micrometer caliper. The 3‐inch diameter ring developed makes quick measurements possible without the use of the micrometer microscope necessary with the 2‐inch rings.
COLOR FORMATION IN RAW LEAD GLAZES1
Authors: Hui Shaw D. Tb
Published: June 2006

Various amounts of practically all of the chromatic elements in the periodic system were introduced individually into a simple lead silicate glaze, and the resulting glazes were analyzed for color with an automatically recording photoelectric color analyzer. The spectrophotometric data were then converted into trichromatic and monochromatic specifications of color. An empirical relationship was then determined between the concentration of the chromatic element and the three attributes of color: hue, saturation, and brilliance. The effect of glaze thickness on color was also studied. It was found that the same laws connecting concentration of the coloring element with the three attributes of color held for all the elements used. A number of elements not previously mentioned in the literature as color‐producing agents were found to give interesting colored glazes. In several cases an element was added to the base glaze in various forms, such as nitrates, chlorides, and oxides. If equivalent amounts were added, the color in all cases was the same regardless of the colorless radical.
PROPERTIES OF SILICA BRICK MANUFACTURED FROM SHARON CONGLOMERATE1
Authors: Frederick C. L.
Published: June 2006

New developments in the field of silicate refractories include greatly improved refractoriness and a high development of desirable qualities in silica refractories manufactured from Sharon conglomerate. The nature of silica refractories in general is discussed and a résumé of materials utilized in the manufacture of silica brick in the United States is given. Several illustrations of this new refractory are included, as well as test data.
SALT GLAZING A CLAY OF LOW VITRIFYING TEMPERATURE1
Authors: Dingledine H. P.
Published: June 2006

The method used to secure a salt glaze on a red‐firing clay which vitrifies at a temperature too low to salt glaze normally consists essentially of raising the temperature quickly for short intervals by rapid combustion of thin soft‐wood edgings and applying the salt at maximum temperature during several successive intervals.
AN AUTOMATIC DEVICE FOR PRODUCING A CURVE COÖRDINATING SHRINKAGE AND DRYING LOSS1
Authors: Spurrier H.
Published: June 2006

An apparatus is described which automatically plots a curve and coordinates the shrinkage associated with the drying loss at any point on the curve. From such curves correct dryir.g schedules may be developed. The apparatus may be used in a drier to indicate correct drying performance and the curves furnish valuable information as to the drying peculiarities of bodies not usually available.
RELATION OF CRUSHING STRENGTH OF SILICA BRICK AT VARIOUS TEMPERATURES TO OTHER PHYSICAL PROPERTIES*
Authors: Cole Sandford S.
Published: June 2006

The failure at elevated temperatures under constant load for silica brick is reported using the Iupuy load test apparatus. The crushing strength at 1500°F, 1800°F. 2100°F, and 2400°F is recorded, as well as the crushing strength at room temperature. The size of test piece utilized normally was 1 by 1 by 2′/2 inches. A definite relationship is shown to exist between the strength at room temperature and that at elevated temperatures. The effect of variation in lime content, bats content, and fluxes is also reported. Data were obtained on brick made from three different quartzites. Additional physical data are reported to give information concerning the properties of the brick tested.
SOME SPECIAL TYPES OF CRAZING*
Authors: Schurecht H. G. , Pols G. R.
Published: June 2006

Little progress has been made in the past to prevent crazing on porous ceramic ware because many of the fundamental causes of this defect were not known. Three sources of crazing are described which have not generally been recognized as causes of this defect. It was found that a type of crazing may be caused by firing ware under a reducing kiln atmosphere. This defect may also be caused by small changes in volume of the body produced by frost action. A special type of crazing may be caused by mechanical pressure on the ware during service. The defects can be prevented by more careful manufacture and selection of raw materials.
THE EFFECT OF BORIC ACID IN RAW MILLED GLAZES*
Authors: Kautz Karl M.
Published: June 2006

A study of the reactions between boric acid and typical ceramic raw materials in slips was made to determine the cause of raw glazes thickening upon standing. Raw zinc oxide, precipitated barium carhonate, and light magnesium carbonate were found to react deleteriously with boric acid in milled slips with thickening or “setting” occurring. This thickening does not occur in many instances when large amounts of white lead are present in the mill batch. Remedies are given which were used to overcome this increase in viscosity in commercial raw glazes by using calcined mixtures and insoluble frits.
STUDY OF THE SHRINKAGE OF DIASPORE CLAYS, PART II1
Authors: Phelps Stuart M.
Published: June 2006

This part of the paper on diaspore deals with the development of methods which will shrink diaspore without firing to exceedingly high temperatures for long periods of time. Experimental work shows that this can be accomplished by a number of shrinkage‐producing materials. It is shown that these should be added in definite percentages, and that the greatest shrinking effect will be produced by fine grinding, high pressure molding of the calcine bobies, and by firing to moderate temperatures. The effect of various gas atmospheres during calcining is pronounced. Commercial brick made by the process developed show properties superior to those of regular diaspore brick.
ALPPARATUS FOR TESTING ENAMELS AND GLAZES FOR RESISTANCE TO CRAZING UNDER THERMAL SHOCK1
Authors: Kinzil C. J.
Published: June 2006

A detailed description is given of apparatus to be used for testing enamels and glazes for resistance to crazing under thermal shock. Flat pieces are recommended for the test and the temperature requirements are given.
DEVELOPMENT OF LOW‐TEMPERATURE ENAMELS ON A FLUORIDE EUTECTIC BASIS1
Authors: Hunt John F. , King R. M.
Published: June 2006

Three fluoride eutectics were substituted for cryolite and fluorspar in three standard enamels: sheet‐steel ground coat, sheet‐steel cover coat, and cast‐iron single coat, with a view to lowering their maturing temperature. Substitution in ground coats produced inferior enamels, but no apparent change was evident in cast‐iron enamels. In the case of sheet‐steel cover coats satisfactory enamels were obtained with a maturing temperature 150°F lower than the original enamel which matured at 1450°F.
THE DIELECTRIC STRENGTH OF PORCELAIN: THE INFLUENCE OF FIRING TEMPERATURE1
Authors: Monack A. J. , Shardlow L. R. , Wamsley D. H.
Published: June 2006

This paper completes the work previously reported by Monack and Shardlow2 The additional puncture voltages in kilovolts per quarter‐inch thickness were cone 13, 60; cone 14, 69.5; cone 15, 67. The puncture voltage increased gradually between cones 9 and 15. Other conditions remaining identical, it was shown that the most uniform body resulted when tired to cone 9.
A TRIAL FOR TESTING CLAY BODIES AND BODY MATERIALS ON A LABORATORY SCALE1
Authors: Wills George A.
Published: June 2006

A body trial is described which can be used to investigate, in the laboratory, the commercial possibilities of the members of a series of bodies, a given body, and the kind of materials to be used in a body. Some examples of its uses are given.
THE RELATION OF SODA‐LIME RATIO TO THE BLENDING OF FELDSPARS1
Authors: Amberg C. R.
Published: June 2006

The possible sources of error in the blending of feldspars are discussed and the constancy of the soda‐lime ratio in commercial feldspars is demonstrated. All pottery feldspars seem to contain nearly the same type of plagioclase which has a soda‐lime ratio of approximately 5.25. It is recommended that this value (Na2O/CaO = 5.25) be used in checking feldspar analyses for accuracy.
A PROPOSED METHOD FOR FELDSPAR FUSION TRIALS1
Authors: Duboxs H. B.
Published: June 2006

The purpose of the present work was to eliminate, if possible, some of the variable factors in making feldspar fusion trials and to develop some means of measuring the deformation by mechanical methods in order to keep a permanent record in definite numerical values.
DESIGN AND TESTING OF A LABORATORY KILN1
Authors: Vauchan W. Harry , Breen J. P.
Published: June 2006

The design of a cross‐fired natural‐gas laboratory kiln is described. The kiln has a ware space of 17.4 cubic feet with a range of heat treatment from cones 010 to 26 and a maximum variation within the ware space of one‐half cone. The results of two economy tests are included, showing an efficiency of about 5.7%.
LABORATORY TEST KILNS1
Authors: Watts A. S. , Carruthers J. L.
Published: June 2006

Three gas‐fired downdraft test kilns built by the Ceramic Engineering Department of the Ohio State University are described and detailed drawings and bills of material are given. Results obtained with each kiln are discussed briefly.
THE FORM OF CRACKS IN BOTTLES1
Authors: Preston F. W.
Published: June 2006

This paper deals briefly with the stress systems and fracture systems in bottles, or more generally in hollow cylindrical or tubular articles of glass or other brittle materials. The forms that the fractures typically take are described and their causes given.