Document Edj60EvL0e5EnZQQZRNvKoX6V

The American Ceramic Society PLAINTIFF'S EXHIBIT cnjas February 15,1993 I hereby certify that the attached copies of Ceramic Abstracts, Volume 18,1939, are true and accurate copies, which are maintained in the normal course of business at the American Ceramic Society, 735 Ceramic Place, Westerville, Ohio 43081. Christine Schnitzer Product Manager Ceramic Information Center nr 735 Ceramic Place Westerville, Ohio 43081-8720 614 890 4700 TWX: 7101109409 Xif- CERAMIC ABSTRACTS Compiled by ThejAmerican Ceramic Society Volume 18, 1939 Ross C. Puuy, Editor Many J. Gibb F.iti.y C. Van Schoicx 1 Assistants Dobotsy J. Wallacb CommitUt on Publications: J. D. Sullivan, Chairman, W. W. Winshif, A. N. Finn. H. E. Mabbazsb. R. C. Pubdy Abstracters: J. B. Austin, A. A. Ayars. L. R. Barrett. K. W. W. Bartlett, A. C. Bevan, D. A. Biddle, W. H. Bruckner, P. Budnikov, J. C. Chaston, L. M. Church, W. M. Cohn, M. V. Condoide, P. S. Dear, Maurice Delangre, R. W. Devillers, Joseph Ford, W. D. Foster, V. D. Frechette, J. L. Gallup, J. D. Gat. R. A. Gregory, Mas Hartenheim, J. J. Hazel. F. G. Heck, R. A. Heindl, P. G. Herold, G. M. Hutt. J. F. Hyde, Herbert Insley, C. B. Jenni, B. Z. Kamich, B. E. Kinkulldn. S. Hondo, Yosio Kora, Walther Kurz, B. B. Lane. V. S. de Marchi, L. F. May, E. H. McClelland, J. M. Noy, J. G. Phillips, Alexis Pincus, M. E. Poor, C. H. Rapp, Katherine Reed, H. K. Richardson, B. C. Ruprecht, A. B. Searle, Stanford Setchell, G. R. Shelton, N. M. Shukri. H. E. Simpson, A. P. Som. E. Stefanowsld, E. W. Stenzel, A. G. Stern, Joseph Stewart, B. H. Strom, L. E- Thiess, Hans Thurnauer. F. V. Tooley, E. J. Vachuska, F. E. Vaerewyck, F. J. Zvanut. Editorial Office: 2525 North High Street, Columbus, Ohio Publication Office: 20th. and Northampton Streets, Easton, Pa. It 18, No. 1939 General 39 ideation , vritigation of uliiminuni du>i as a possible respiratory rocess cod i-irard resulted from the appearance in 1034 at the Oc- substanta iipational Disease Clinic, Berlin, of a patient who had been i consist <praying aluminum bronxe for nearly a year and who sd salts, t 'cowed signs of a lung disease of a not very clear character. ferric con r3riy in 1934 an Italian doctor of the throat and nose provide -jinic at the University of Rome published his observa- eOi. to tl ions upon the efTect of aluminum dust on the air passages. - precipitv The present research includes (1) the components and properties of the substance (which docs not occur in na- in*. G. I ure in metallic form but is the result of mechanical and 1,718. Sept chemical processes). (2) 30 citations of previous studies on ins a stab) ;he injurious effects derived from the preparation of preparing i Aluminum and its industrial uses, (3) the- detailed case* * molccula history of the patient, with laboratory findings and Roent .rt of silica gen studies, (4) an intensive investigation of 70 workers sufficient t in aluminum works, and (3) a critical analysis of the lion of sub Italian data. The hazards were found to be completely he tempers negative, both in the processes of making aluminum and :b to tram i'rom inhalation of the dust. K.R. h substan Inhalation of dust and control of dust hazards. W. C. J- Jjuoes. Concrete, Cement Hill Ed., 46, 200-201, 216-17 . 1938).--Many persons inhale excessive dust into their lungs, with coal and iron-ore dust coloring the lung tissue. In most cases, however, these changes are of no more im portance than callouses on the hands. Only two dusts actually cause diseases on inhalation, silicon dioxide (us xy. Anon ually quartz) and asbestos. Only particles below 10 m ilicosis de are effective, and these must be breathed in high concen letals mon tration and over a long period of time. A safe maximum ; inhalatioc concentration is 5 million panicles of quartz dust per cu. and clinics, it. The exposure of each man should be reduced to of artifida particle-hours to be comparable. The length of time s not coo necessary to develop silicosis is controlled by (I) con of silicosii centration of dust, (2) proportion of free silica, (3) length sd. nf exposure, and (4) general health of the employee. It M.H. is unusual to have silicosis develop in less than seven years. iciency and Dust should be removed at the source. W.D.F. (20| 37-58. Occupational diseases of the lungs in agricultural work ilitated bj ers. Richard Fawcitt. Brit. Jour. Radiol., -II, 378-92 ng system June, 1938).--In 1936, 749.700 persons were employed in t conveyers, the agriculture of Great Britain, forming one of the largest :g extensive working groups. F,, as a country practitioner in the of the old hill; of the Lake District, early became familiar with the material w icricul'iiral types of asthma, bronchitis, and pneumonia wo or three which usually ran a protracted course among these workers; H.E.S. -.covers-. when occurring, appeared largely due to potas- l\ S. Pub. -ium iodide and creosote administration. The infections lrticle. rep- the working people are subject to are listed as organic rt selective matte* (microfungi and bacteria) existing in grasses, ve materiaL >traw, grain, fruits, the soil, and in the excreta of farm tatis-e docu- animals; only occasionally docs inorganic matter affect rol has evi- hem. e.`., men carting siliceous stones. The details of Jealing with fungi infection and the procedure in identification are neasures ait briefly and clearly given; types of fungi prcdominantlv resourceful- aficciing six special groups of farm hands, e.g., hay or grain bed. Stress workers, stablemen, gardeners, etc., are described, with intended u '.hv resulting symptoms and injury. Nine points to be by lengthen -.vnsidcred in a doctor's study of such cases are systemat- laminations cully presented for case-history record. Special com to allow the ment is made upon the agricultural groups, with citations out process. Jotu case reports; 13 large-size radiographic rcpiroduc- K.R. 'ns of chest phenomena in the various fungi invasions tx Since*. - "neemed arc interpreted for the lay reader. F, emphasizes liscusses the ; here occupational diseases as rare, seldom reaching radio- lies and the cical departments or diagnosis.- Yet common micro- n with such fungi. often innocuous, do become pathogenic under cer- ay minerals. '-uiu conditions. The incidence of harmful infection is er increased re common and more widespread than is generally Ibid.. (5561 ^dized. 19 reference*. K.R. <d shapes is . Practical significance of silicate research. A. Dietzel. itish Patent n-cyrr/i. Ber., 14 [5] 101-64 (1930). J.F.H. Process lot Prevention of disease in industry. D. Hunter. Ind. the like or 13, 134-36 (1P371.--The main principles undcrlv- R-VH. :,1_S the prevention of disease iu industry arc (1) protection n. especially '* workmen by law such as workmen's compensation acts. ,>:Cfverbekyg,, - medical inspection under state support, (3) education :::;ih:prough in- *' to the nature of the danger. (41 importance of clean liness (cleanliness of work places, bodily cleanliness, and general hygiene), and (5) reduction of manual operations. H.E.S. Preventive measures in the use of crystalline silica. M. Jd. Shaper. Ind. bled.. 7 (81 472-75 (1938).--S. pre- tents the subject systematically under three major as pects: (A) medical. (B) engineering, and (C) managerial. He suggests that, before any protective measures in the use. of crystalline silica are resorted to. the fact be estab lished that a silica hazard exists. Data involved include (1) a definite exposure to dust known to contain a certain percentage of silica and (2) sufficient dust exposure, as estimated by dust count and dust composition, to cause silicosis if the exposure is cootinut-d over a sufficiently long period of time. In emphasizing (B), S. states that it is entirely the problem of the engineer to prevent silico sis. The medical director can only check the adequacy of the engineer's methods of- control. KJL Recovery metabolism of silicotic!. A. BOhme. Arch. Gexerbepath. be Gcxerbehyg.. 8, 601-10 (1938).--B. re cords the metabolism studies and muscular tests applied to silicotics in varying stages of the disease to improve their greatly impaired respiratory capacity and muscular action, if possible, and at least to record the success or failure of such efforts. Tables show a comparison of the metabolism of normal persons after 15 bendings of the knees (as in climbing stairs), after taking food, and after rest with the metabolism of the silicotics (four having a lessened industrial capacity of 80% and six lessened to 50 or 60% capacity). Items tabulated include age and vital capacity after food and after rest; respiration, minute volume, and Oi requirement; the respiratory quotient, conversion rise in %, and these values after rest; and the Ot needs (cc./min.). In the severest forms of silicosis, the total variation in the 10-min. recovery periods was higher than the highest, shown in normal persons. Acid ab sorption had not returned to normal after 10 min., while in normal persons it was completed in 3 or. at most, 6 min. The minute values of respiration in the most severely 31 subjects was markedly raised after the work attempted, and even after the 10 min. rest, it did not attain its pre vious value. The higher the lessened capacity for work in percentage value, the more the records varied in severe silicosis. Experiments on early or middle-period sili cotics showed fewer certain, unmistakable results, their working capacity being still much higher. ICR. Research Laboratories of Mellon Institute. Harry S. Coleman. Ind. Eng. Chem., Anal. Ed., 10 (9] 550-5S (1938).--The design, construction, and equipment of the research laboratories in the new Mellon Institute budding are described in detail. Illustrated. F.G.H. Research laboratory of the Columbia Chemical Division of the Pittsburgh Plate Glass Co. Anon. Ind. Eng. Chem., Anal. Ed., 10 (61 329-30 (1938).--The physical equipment is briefly described. Illustrated. F.G.H. Safety and hygiene in the foundry: I, Medical aspects. R. R. Jones. Trans. Amer. Foundrymen's Asm., 8 12] 554-64 (1937).--The more important industrial health problems associated with the foundry industry are those related to (a) general physical characteristics of the build ing. (b) housekeeping practices, (c) drinking water supply and lunchroom and toilet facilities, (d) exposure to extreme temperatures, (e) exposure to toxic or irritating dust, fumes, and gases, and (J) medical supervision. Success in the control of industrial health hazards is primarily de pendent upon the employer's attitude toward the problem. Discussion. J. A. Britton kt al. Ibid., pp. 576-88. H.E.S. Hermann August Seger. Anon. Bull. Amer. Ceram. Soc.. 17 [11 ] 403-64 (193S). Silicate research and engineering. TV. Eitel. Z. I'er. Deut. Ing., 80 12) 37--41 (1930).--The conditions and status of silicate research as carried out in the Raiser Wilhelm Institute in Berlin with regard to glass, ceramics, cements, mortars, and concrete and the relation to ap plication in practical engineering are explained. M.H. . Silicosis among grinders. J. L. A. Grout. Brit. Jour. Radinl.. 11, 3HO-70 (June. 193SV--This interesting No. 2 193? General 63 1 and re-' . 11 the ion. they .ck in aU 'time labor limit in the German hard-coal industry for do* jatmospheric localities, is an arbitrary limit. In general, working capacity seems to be lowered by high temperatures to 00% values. The physiological reactions however. $ are reher* and :o photo-. 0f men continually vary when climatic conditions grow constantly worse. Injury to health from dry and high temperatures alone can not be definitely established, the relation to humidity present always being a factor. Omit I having. ting [the heat factor, a humidity of 25* seems endurable. - a tingle, ne points surfaces In regard to the elimination by the skin or lungs under high: and humid conditions, results appear personal and individual. Greater water elimination occurs in men . Debye acclimated to hot humid air than in those not inured. the form c X-rays e lengths e length, Mcb habicually rather than occasionally at work elimi nate' larger quantities of water. Rising temperatures in a dry climate and rise in humidity increase elimination of. water through the skin. Individuals showed, in their diffracted that they elimination through the skin, none of the expected cor respondences which might be traced back to these chang the pan-' ing environal states. In this investigation, bodily tem n on the peratures generally rose very little proportionally under .5 formed, the roent* made in. xamining.' higher outside temperatures and increased humidity. Blood pressure, respiratory frequency, and pulse frequency showed no quantitative relation to selected climatic con ditions. Fourteen diagrams and two tables are given. ys where, 18 references. KJL yway that; diagram, Dust content in an asbestosis lung and the behavior of the iso-called asbestosis bodies. X. Sundics and A. ter inter-; Bygden. Arch. Ceaerbepath. fi*.Ceteerbehyg.. 26-70 f Debye- (1937*1938).--This research upon the effects of asbestos d by re- dust when breathed in by industrial workers in asbestos is turned was carried out by the State Geologist and the State the tiny, Chemist of the Swedish Geological Survey. They indi of curved - cate! the differences between the asbestosis lung and the . Roent'ooratories16 [1] 32 silicotic, the former being due to the action of a basic silicate (isotropic), accumulating in yellowish or reddishbrown needle-like masses, and the silicotic being due to M.V.C. quartz (SiO-) degenerative action, exhibited in nodules and: other quite different manifestations. Asbestosis was | first identified in 1906 by an English physician, ed. *Ost: . Leipzig. Montague Murray, of the English Compensation Com mittee of Industrial Diseases. The chief research studies . 47 15531 since that time are reviewed by these authors in their reedited; cumulative value. Their own procedure in isolating >f ceramic asbestos dust and its accompanying "asbestosis bodies" chemical by treating the affected lung substance with hydrogen are men; book is peroxide, also by purely mechanical action upon a `heavy" solution, is given together with the ascertained percentage R.A.H. values derived chemically from the eight or more mineral components of asbestos. For the entire lung, approxima tions were 5.6 g. asbestos bodies, 0.S free asbestos needles, materials, and ;1.4 total asbestos content. Total dust respired by the lting Co.). given lung was about 2.S g. Some of the bodies built up in needle form were composed of titanium oxide (TiO>). 3 silicate* Intensive study and analysis of the coverings of the bodies A Penn- sem to indicate that they are blood derivatives after V. 9. 1938 the mineral has entered the lung. The fibrosis ultimately' and i generally distributed through the lung following the cCullocb dust inhalations appears to have definite relation to the 2.137.058. presence of the asbestos needles and their movements about the lung under the mechanical stimulation due to respirator}* movements. 12 photomicrographs. K.R. Heinrich Ries. Anon*. Bull. Amer. Ceram. Soe.. 17 .12) 490-5*1 (1938). History of glass industry at New York World's Fair. with high Anon*. Bull. Amer. Ceram. Soc.. 17 (121 489 (1938). eh. Cmet' Hygienic dangers of nonferrous metals. H. Bercek. he authors Hcall-irtschaft, 17 [32] St13-07 (1938).--B. discusses the uc to high dangers in handling Pb, Hg. Zn. Cd. As. Yb. Se. Te, Cr. uch as are Mi. Cu. Mn. light metals. W. Tl. and Os due to inhalation of water-con* du>t or vapors or contact with each individual metal and conditions- "Wans for eliminating or at least minimizing the risk. . high tem- M.H. as such is Lung findings in foundry workers. O. A. S.andcr. i) decrease imer. J,,,,r. p,,b. Health. 28, 601-609 (1938).--Of the conditions various occupations in foundries, sandblasting is the most vr. so that azardous if done wit hunt protection; otherwise sand 1 as a full* "'nipping ami grinding of large castings arc the most danger ous in regard to the health of the employees. Data obtained during a four-year survey are as follows: Yon exposure No. employees SUieetic I- 5 6-10 11-15 16-20 21-25 26-30 31-40 41-50 1174 S12 602 532 365 208 215 47 0.5 3 5 10 1v5 21 21 From this data, S. concludes that simple silicosis as seen in foundry workers is only very slowly progressive, so much so that no visible changes appeared in four years observa tions, and is only rarely sufficiently advanced to cause symptoms and incapacity for work. Control of the foundry hazard is best accomplished by elimination at its source of the dust generated by sandblasting, sand chip ping, sand grinding, and shake-out operations. Pre employment and periodic examinations are essential to prevent tubercular individuals from carrying on a dusty trade and to discover new infection and reactivation cases as they arise. B.C.R. Selenium as a potential industrial hazard. H. C. Dudley. U. S. Pub. Health Repts.. S3 [8] 231-92 (1938). --D. points out those industries which may have un recognized hazards due to the possession of selenium bearing materials. Increasing uses and applications of the element and its compounds necessitate the warning that in certain combinations selenium is toxic. Hence, in dustrial plants where these substances are utilized will need to afford their workers adequate protection. Sele nium is obtained as a by-product from electrolytic refining of copper: this is the chief commercial source. Its first use was largely confined to the glass and ceramic industries, where it was used as a glass decolorizer and for the pro duction of red glass and glazes. Rubber manufacturers next made heavy demands on domestic copper refineries: recent increased uses have not only exhausted domestic supplies but have required importation in larger and larger quantities. The ceramic industry alone has utilized more than 170.000 lb. According to D-. new sources of supply will have to be opened. Tbe occur rence and location in 21 states of 15 minerals, with the selenium parts per million, are tabulated. The selenium content of the earth's crust has been approximated at 0.005%; nearly all sulfur and sulfide deposits contain it: certain western phosphate rocks show amounts of even 55 parts to the million. In a large number of soil samples taken from areas surrounding smelters near Butte and Anaconda, Mont., Rennet, Calif., and Copper Hill, Tenn.. selenium was found: it decreased in quantitity with distance from the smelter. Extensive animal experimenta tion by ingesting selenium compounds shows that such substances, when soluble, have toxic effects, both acute and chronic. Early cellular destruction occurs in the liver, with later pathological characteristic changes throughout the organism. Guinea pigs experienced severe metamorphoses in the liver and, after inhalation of hydrogen selenide, hypertrophy of the spleen. Men employed in copper refineries which extract or purify selenium display the symptoms, respiratory and gastric, which characterize metal poisoning generally. The excretion of selenium in the urine, however, is conclusive evidence of selenium absorption by workers. D. gives in detail the procedure for urinalysis in detecting and estimating selenium in the urine. In the tabulation of industries with possible selenium hazards, tbe glass and ceramic industries are in the secondary group, t'.e.. they utilize selenium and its compounds as basic materials in manufacturing processes. The immediate sources of hazards involved in this group are given as melting pots and furnaces, the fumes of Se and SeO- being given off. Tlic sampling o( vapors and gaseous constituents of in dustrial plant atmospheres and contaminations of labora tory workrooms is explained in detail in connection with 103 Ceramic Abstracts Vol. US. N*0. ,5 tests and indicating just how closely the sampling repre sents the true character of a batch of material being tested. F.P.P. Volumeoic analysis of copper. M. Sccrra and Y. Yamamoto. Jour. Hoc. Cktm. Ind. Japan, 41 [2| 348 (1933).--Copper can be reduced to the cuprous ion in an solution with sodium sulfite. This cuprous ion can be titrated with potassium permanganate solution. After the reduction is complete, the solution is acidified to expel the excess sulfur dioxide gas. An addition of a small amount of chlorine ion in the form of sodium chloride is necessary to avoid the precipitation of cuprous oxide. The sample of solution containing about 0.16 g. of copper should be treated as follows: pour the test solution into a oOO-cc. daslc. dissolve it in a small amount of water, and make it slightly acid, either with sulfuric acid or sodium hydroxide solution; add 30 cc. of 10% solution of sodium sulfite and 8 cc. of 10% solution of sodium chloride: boil and redissolve the yellow precipitate in the daslc (double salt of cuprous sulfite and sodium sulfite) and make the solution colorless: add 30 cc. hot sulfuric acid (prepared at this time by mixing `JO cc. of .10 .V sulfur- acid and -JO cc. of ti .V sulfuric acid). The white prj'". cipitate of cuprous chloride is formed, and sulfur dioxin, gas is expelled violently. Boiling is continued for lj -j 20 min. to expel sulfur dioxide gas completely and to exp> excess hydrogen chloride. To till the flask with carbo-' dioxide. 30 cc. of 3% sodium carbonate solution are added* Heating is discontinued and the solution is titrated wi-.- 1/tO tY potassium permanganate solution which contain! about 3% sodium carbonate. The presence of Pb*. an " ' Mn*. etc., has no effect; therefore, no preliminary separii tion of these metals is needed. M.V.C. PATENTS Making alkali metal silicates. C. R. McDani*(Diamond Alkali Co.), (f. 5. 2.133.372. April 11. Ia';* (March 7. 193.5). Production of polysilicates. Dessacx Fcls. Fr. >:. 732, Oct. 3. 1937; Chem.-Z63 [191 173 (1939). D.A.3. General Air conditioning in industry: I. \V. L. Fleishex, A. between liquids' and gases, as it presencs the gaseous E. Stacey. F. C. Hoccktsn. and M. B. Fbeoeese*. reactant in the form of minute bubbles, thus giving :i- Heating, Piping tif Air Conditioning, 11 (2) 107-11 maximum surface for reaction. (2) Biscuit porcelain li (1939).--This study was conducted in the research labora used in Altering operations where it is necessary to sepa tory of the American Society of Heating and Ventilating rate extremely minute particles from acidic or other cor Engineers at the Pittsburgh Experiment Station of the rosive liquors. It resembles porcelain in color and ex V. S. Bureau of Mines. The physiological, reactions of position. but differs from it in that it is highly porous. [; men while carrying on light work in atmospheric condi pore dimension can be regulated in size from 13 micros- tions including effective temperatures from < < * to 92*F down to below l micron. The "oacure of its ingredieau with relative humidities of tiO. 73. and 90% were inves- and the temperature at which it is flred ensure resistant.-: tigated. The history of previous investigations is dealt to acids by the more siliceous bodies or to caustic alkaiii with. Two charts. J.L.G. (where the alumina content predominates). Bisect Appearance and prevention of silicosis and asbestosis. porcelain is also used for electrolytic processes in ti: Eniuco C. Viguani. Ross. Sled. Appiieata Lavoro filtration of oils and concentration of rubber latex, i.-7 Ind., 9, 387-94 (1933) ; Chem. Abe.. S3, 2244 (1939).--A Diatomaceous or kieselguhr bodies, while less resistac: review is given. to corrosive chemicals chan either biscuit porcelain -:r Asbestosis. R. R. Sayeks and W. C. Dreescn. Amer. quartzite, combine small pore size wich high permeioiii:" Jour. Pub. Health, 29 [3| 203 (1939).--In a study of the and are used for the filtration of neutral, or nearly neuerx. North Carolina textile mills using asbestos fiber, a hy liquids. They are usually employed in the form of cacci= drated magnesium silicate containing no quartz, pul or hollow cylinders of small diameter, closed at one see monary asbestosis was the principal defect found. Ex or with both ends open, up to a length of 12 in. A.B.5. posures ranged from 0.10 to 76 million particies/cu. fa. Floors for industrial purposes. R. Fctzmaitsuce an: Persons exposed from 3 to 10 years to dust concentrations F. M. Lea. Read before last. Chem. Eag. and In*: exceeding 3 million particles/cu. ft. showed definite Struct. Eng.. London. Jaa.. 1939: abstracted in Ciu~ evidence of asbestosis. Daca so far obtained indicate Trade Jour., 104, 79-80. 112 (1939). L.R.B. that 3 million particles/cu. ft. is the maximum safe Industrial impairment of health and poisoning in ts: concentration. * B.C.R. metal-working industry. Fseitag. Oberfldehenteeh.. I' Ceramic filters. Anon. Chem. Age (Londonl, 40, [41 33-36 (1939).--F. discusses the danger of silicosis - 43 (1939).--A new range of porous ceramic filtering mate men working with sandblasting. Poisoning by nitre-- rials has been introduced by a Glasgow firm. These gases in pickling, etching, and coloring processes, by C" ceramic materials are resistant to corrosive fluids and are salts in Cr plating, by Pb in Pb welding, by CO in ox?- made with a pore size ranging from below one micron up acetyiene welding, and by toxic gases developed in merg to several hundred microns, the distribution of pores and ing and hardening processes is also discussed. M.H _ pore density being exactly regulated. The materials are Lifa and' work of Henry LeChatelier (1S30-19J6). J produced in a great variety of shapes--they can be Pascal. Bull. Soe. Chim. Hem.. (5| 4 [1U| lSoT-n- sawed, cut. or ground to suit individual requirements-- (1937); see Bull. Amer. Ceram. Soc.. 16 [4| 1.55--53 (19:>- and their mechanical strength and durability are very Ceram. Abs.. 16 [101 316-22 (1937). D.A.5. high. The materials, quartzite, biscuit porcelain, and diatomaceous or kieselguhr bodies, are described as fol lows: (l) Quartzite filters in the form of square or circular tile, of different thicknesses and sizes, and hollow PATENTS Repairing cement toe ceramic objects. E. Rosentx> cylinders from 2 in. to 6 in. in diameter aad up to 24 in. Brit. 300.373. Feb. 22. 1939 (Aug. 12. 1937). .; long are produced in several grades, varying from coarse Satin white pigment end procesa of making. L- - ; grained bodies of extreme permeability down to a close- Wouc. U. S. 2.143.149. Jaa. 24. 1939 (Feb. 4, 1935). ^ grained type with a pore size as tow as 10 microns but of procesa comprises treating finely divided day wich suu-'j " such high pore density that it ensures rapid permeability. acid, producing thereby a solution containing alurr.in'-' - The- high rates of dow obtainable with these filters are sulfate together with coloring impurities and an insoiuf' exemplified by the P27 grade which gives a flow of 1700 day residue, removing coloring ingredients from the gallons of water/sq. ft./hr. at 5 lb. pressure. Quartzite tion, and reacting the so-puritied solution with hydra1*'! filters are particularly suitable for industrial filtering and lime in Che presence of the day residue. ' aerating operations of liquids and gases, especially where TUa tar use in sewage filters. J. E. Tccker. " j resistance to corrosive fluids is essentia) and in reactions 300.378. Feb. 22. 1939 (tiept. 13, 1937).