Document 93G441O7rk6xNEbqLkE4mNGj5

CERAMIC ABSTRACTS Compiled by The American Ceramic Society 1948 Cauxxs S. Psaao, Editor Maay J. Goa. Assistant Editor Doeotky Donohue, Editorial Assistant Committee an Publications: K. C. Lyon, Chairman; JCaju. ScKWA*TnvAi.EJt. R. E. Bock, anp J. J. Canttelb Technical Advisers: L. G. Faebeh. Rauk Rose, and A. TV. Allen A. H. Adams F. C. Anaaee Willred Ashworth X. N. Ault Walter Bank L. R. Barrett R. Barta L. Barxagbi W. R. Beck J. J. Beinlich A. C Bevaa ABSTRACTERS Associated Technical Services British Ceramic Research Association Bureau International d*Etudes Techniques Ceramiqaes A J. Bidduiph R. H. Bollinger Claudts Boynton lan Campbell G; S. Douglas W. D. Foster T. J. Frnnkei R. A Gregory P. Grodsinski A. J. Kaecker, Jr. Mas Hartenhcim M. P. Kaydoo F. G. Heck 2. Hochman R. H. Hooker G. M. Hutt Collin Hyde J. F. Hyde L. J. Jacobs B. Z. Kamich D. F. June M. hi. V. Rleiman N. J. Kreidl S. M. Lane E. D. Maher F. R. Matson L. R. McCreight L. M. Merritt J.G. Mohr J. M. Nor S. & Obenshain T. G. Pett D. G. Pierce Alexis Pincus V. J. Plankenhom J. E. Priestley A. T. Prince K. K. Richardson N, Schrewelius A. B. SearJe J. O. Semmetmaft F. P. Shonkwiler Haas Tburoauer \V. O. Williamson Publication Office: 20th and Northampton Streets. Eastoo, Pa. Editorial Ofice: 2525 North High Street, Columbus 2. Ohio t /tm32?c\.. v; 260 Ceramic Abstracts November 104: iOL-rt pu curtain* insi*le funtacus. and simplified. smaller Sow to make a silk screen. Anon. Ceram. tad so plants; i31 predictions for whiteware which include ll 97 11946). C.O.H [ready shortened maturing schedules. custom-made kilns, How to set up a simple perpetual inventory system. unbreakable china, uncontammated raw material, handling 0. L. Got'CH. Am. Paint J., 32 (301 4<t-ki U948). -A timed to make storage unnecessary. automatic hatching, * system through which any manufacturer or supplier casting in a fraction of the proem time, faster jiggcring. numerous artides can determine profitable items, reserve radiant heat and atomic fuel, and rapid decorating; (41 stock quantities, and control production, mark-ups. un predictions for (lass which include smaller plants, pneu* reserves of raw materials can be set up usiug 3 X 5 in. ii'v static material handling, prvsintering for fast melts, trend -- cards in a visible reference type file. Suggestions .irc toward automatic forming combination annealinf and offered concerning actual data to be entered ou each cord. beat-treacing, lightweight glassi throw-away containers, A ficticious case illustrates the value of such a system. and oxygen meltin(. Twelve charts with curves predict , AJ.lt. the rise and fall of market.conditions for major appliances, t. Immersion 'media containing methylene iodide. R,,u. architectural porcelain, porcelain sanitary ware, hollow EXT L. Dajlnzal. .4m. Mineral.. 53,340-52 (1943).--The ware, dinnerware. door and wall tile, vitreous sanitary usefulness of methylene iodide in immersion media U ware, electrical porcelain, (lass containers, dat (lass. (la> emphasized. The nuuUnear relationship of indices of re- tableware, and structural (lass.* CC.B. fraction to composition by volume of some liquids contain- Controlling abnormal dust exposures. M. W. Thomp -- inf methylene iodide is shown by experimental data. At: son. Occufaitianut Hazards, 10 (4| 12-13 1.1948).--Tae empirical equation ha* been devised for calculating ;iu removal of dust from places of ori(in by mechanical means indices of mixture* of methylene iodide and l-broraotupii- and by moistening materials and air. as adopted by the thalene from volume percentage data: m 1.6567 -- American dinnerware industry, is discussed. M.Ha. e l.'tUT (433Jx 4- 37x*). where * is index and x is CH:l; Dried molding sand. P. Nicolas. Fonderie, 1943, (vol. ^). Calculated indices-show close agreement with No. 29. 1172-76.--The results of tests are given in curva* experimental value*. The decomposition, purification, of humidity content after drying. density as a function o` humidity, and compressive strength as a function of hu midity and of exposure to air. The optimum values of a -- and preservation of methylene iodide i* references. I figure. Msatil hygiene and industrial health. discussed. 17 W.D.F. R. C. Xovtcs. -and containing day with a fineness of AF-A ll!> Halt. Safety AVwr, 56 (6| 23-29. 33-34 (1947).--Emo were obtained with a humidification of 7^ for plastirity. .V^. for cohesion in the green state, and U)^ for strength after drying. To obtain a dne surface on the cast pieces the dried molds should be coated with stove black contain ing about 3*0 volatile maer and 25 to 30ci ash: the grain size should be less than 0.7 mm. For steel castings, good results are obtained with a coating having a base of very fine silica; for cuprous alloys, a coating of silica and also one having a base of ocher are used; a coating composed of graphite, ocher or day. and talc is used for general pur poses. M.Ha. -- * tional factors in the adjustment of an employee to his work are beginning to be recognized as an important factor in safety. W.A Methods of sterilization of protective equipment. Walts* F. Scholl .4m. Imt. Hyy. Assn. Quart.. 8 -4. 92 (1947).--A liquid soap solution is used, followed bv a stream of warm water to remove the soap. The disinfec tant Rocal is then used after diluting 6 os. with 6 gaL of water; the bath is used for a week. At one plant about 75 respirators, 3U9 goggles, 100 goggle cases.. 12 rubber suits. 5 rubber boots, and 65 miscellaneous pieces are sterilized in one week. Time of immersion in the bath is U> min. Dropped-caissoa shaft sinking. Wtu.Lut S. Cots, Ja_' The hands are not affected by immersion in the Roeal. En%. Mintn% 149 (4| 32-63 (1946).--Bauxite deposits Zephiran chloride is also satisfactory but more expensive. in Saline and Pulaski Counties. Ark., require many shallow W.D.F. shafts in proportion to the tonnage mined. Conventional -- Pulmonary dust disease. A R. Ridoell. tnd. .1Ad- shaft sinking is not advisable due to layers of quicksand. 17, 168-70 (1948).--Silicosis is the most important but A concrete caisson was made 18 in. thick and with an inside there are other dust diseases. The status of aluminum as diameter of S ft. for a shaft, [t was planned to dig out the a therapeutic agent for silicosis has not yet been deter* middle, drop the caisson, and put another ring of concrete f mined. Fumes from heating bauxite to make corundum and repeat, but considerable trouble was encountered; can cause trouble. The fume contains much alumina, however, it was finally completed to a 2tW ft. depth. Fu silica; etc. Early cases are symptom-free with a slight ture projects should (1) avoid test holes closer than 20 ft.. lung shadowing. Later the symptoms may simulate (2) hare adjustable guides for aligning the shell. (37 have _ pneumonia and heart and the shadowing spread*. guidc runners to keep the caisson aligned. (4) have a gasket Cadmium or cadmium compounds, richer as fume or dust, to stop sand blows, and (5) use water-tight joints between cause a serious lung disease. During the war beryllium all pours. 4 figures. W.D.F. poisoning became known. Asbestosis has long been Factors which will influence ceramics in next 25 years. known. Workers in a very dusty talc mill showed lung Anon. Ceram. tnd~ 50 [61 35 (1948).--Fifteen factors 9 damage, but the miners did.not. The talc was fibrous and y which will influence the next quarter century in ceramics contained 30 to free silica. There are some benign are as follows: Americans will live better; there will be pneumoconioses, such us siderosis, which do not affect the more family units; the population trend is up; the average length of life. 7 references. W.D.F. Man MVtt cl 14(1. .filler mipr . ing i Se T.tv: for were whit whil- Si 2UIof < crys: cryp tripe vim gives and trou land tion. insu; and smel Mild abot in n S\ 1-6 Carr font T2 P. P (194 T: in tl Poo aids "Po: Tan port. Potr potti XJ. sear. deal used tv Wf udu of ra A tv Amt 3th Figu give age will be slightly older; military preparation will be __ Photoceramic technique.. S. A Bcxzon. Abstracted planned in billions; commercial construction has only m SUkd'naya. i Keram. prom.. 1947, No. 9. pp. 17-18.-- started; institutional and government needs involve huge Details are given for transferring images from glass onto construction; the European Recovery Program will tax ceramic ware. The following reagents are used: 11) for American production; competitive raw materials are being t cleaning the glass, a solution containing 4 gm. of ammo- depleted; home and rental construction will increase; " nium dichromate, 10 gm. of dextrin, and 20 gm. of sugar in backlogs still exist and may be increased; technological US) cc. of water: (2) for transferring the image from the developments will broaden markets: industrial construc glass onto the ceramic ware, a solution consisting of 50 col* tion will continue strong; competitive product develop lodion,30ether.and20%of96*alcohol; (3) adark-brown ments will challenge ceramics; and labor relations will be --eoloc containing the pigments Fe<OH). C0(0K);. and mutually more enlightened; C.G.B. ZnO in the proportion of 2: i: l and -a black color containing Failure to block doorways of freight cars causes severs the pigments Fe(0.4)*. MnCO*. and CO<OH)- in the pro; damage to packaged freight. Anon. .4m. Paint if. portion of 2:1:4. The flux for these colors consist* -'* (231 76-80 (1948).--A series of documentary photograph* i Pb,0 75. quartz 12.7, and boric acid 12.5**. B.Z.iC taken by the Shipping Coutainer Institute show .freight Report oa British Industries Fair. Jack Baoo. damage, its causes, and the results. The value of hlockin; Ceram, bid.. 50 (6)131(1948).* C.G-B- A. FU tf abst Pho indu serif i sat : 73^ proc scril vate min: and ape doorways to prevent load shifting n stressed, and methods Research oo asbestos fibers. M. S. Baoou.ct. 7 "<** are suggested to prevent such shifting. AJ.H. Can. inU. Minint Met., 51, 213-16 (1948).--The John' t Pulmonary Dust Disease A. R. RIDDEti, BwA, MJL, DJ>M. .. Opinions concerning dusts and pulmonary considerable value in the estimate of disability. disease have changed somewhat during the A review of the symptoms and signs presented last few years. For a considerable period followby 637 persons with silicosis was recently made. ing 1918 attention was chiefly centered on silica. This offered information which may be usefully Busts were classified as active or Inert according applied. The investigation confirmed the finding as the reaction they occasioned is the lungs re* that dyspnea is the commonest symptom and lim iembled or differed from that produced by silica. ited expansion the commonest sign. It also dis-* Although silica is still recognized as the most dosed, that of 203 persons with a history of important dust concerned with dust lung in having had night sweats, 117, or approximately jury, it has gradually become apparent that dusts 58%, had positive sputum. Bacilli were demon other than silica and the silicate asbestos may be strated either at the original examination, or involved in pulmonary disorders. later on follow up. It indicated, that 70, or S0%, A description of silicosis is superfluous at of those with hemoptysis were tuberculous, and $j present The disease has received so much atten that 184, or 75%, of those whose fingers were I tion and has been discussed so often that you are clubbed or who had curving of the finger nails, all conversant with its general features. You had positive sputum, or were dead when the an realize that silica dust inhalation, if the quantity alysis was made. ' of dust inhaled is adequate, may result in lung It will be realized that for practical purposes, fibrosis of a special nature. Collagenous nodule diagnosis in silicosis involves the differentiation formation is characteristic of this process, but of type as well as recognition of the disease. its regular deposition may be altered often pro Commonly this is made on the radiographic ap foundly by accompanying infectious processes, pearance a case presents. Cases with clear cut or by admixture of the dusts of other materials uniform nodulation are interpreted as simple, with silica. It is general knowledge that silicosis and those with conglomerate or massive shadow is prone to associstion with tuberculosis, but ing as complicated. Although this may be a use the implication may not be so fully appreciated. ful working rule In relation to the interpretation ' The late ds. gassnss1 is reported to have ad- of radiograms, there are many exceptions to it. .. vanced the opinion that, when ehronie, a com- Xot infrequently the radiographically simple case bination of silicosis with' tuberculosis constituted will prove to be complicated, and no evidence of - a disease quite different from either of the other an infectious process can be demonstrated in the * two contributing conditions. Certainly it is dif radiographically complicated, even at autopsy. ficult to treat. As a rule it gradually progresses Compensation complicates the silicosis prob in spite of what is attempted, and surgical mea lem. With diagnosis so dependent on the inter sures are unsatisfactory. This disease may be pretation of radiographic shadowing as is the- seriously disabling, although those affected are case at present, it is well to remember that heavy i?g? not always obviously ilL or prominent shadowing in the lung fields or The importance of tuberculosis in conjunction even nodulation, does not necessarily denote fibro \ with silicosis is illustrated by information sup sis or silicosis. These appearances, commonly M plied by consideration of the causes of death in ascribed to the effects of silica, may be simulated a series of 436, silicotics on whom we have rec by lung changes related to other conditions than ords. The persons Concerned had been employed silicosis, in which there is often no fibrosis. in various occupations carrying a silica hazard. When eases presenting such radiographic ap A little more than half of them-were miners. pearance lack a history of dust exposure the Pulmonary tuberculosis caused the deaths of situation may not be too difficult, but with such 62% of the persons comprising the whole senes, a history they may cause considerable confusion. and was responsible for 68% In the mining group. We have found the more important of these con Estimations of disability are notoriously fusing conditions to be--heart diseases, particu troublesome in silicotics. It would seem that larly mitral stenosis, certain funpis infec these are too often based on radiographic ap tions, benign pneumoconioses, disseminated new pearances together with attempted measurements growths of the lung, and sometimes pulmonary of breathing capacity, and that other useful in tuberculosis with a miliary distribution. formation is apt to be neglected. In assessing Aluminum dust employed in the treatment of. disability the clinical picture should be viewed or as a prophylactic In silicosis, has received as a whole. Careful consideration of the infor much attention in this regard during the last few mation afforded by the symptomatology and clin years. It is administered in two forms. as finely ical findings in the individual cases, may be of divided metallic aluminum, and as.aluminum hy droxide. The metallic powder is the more im at lh* Annual < Xh-wbaW Asotia. *r I.sawttuu Phtjutus* ani* Srarnixn. t.Annin*. Mt-hi. cun. Xanrh t ISO. portant agent, and a: present many persons^ are receiving it both here and abroad. Its admrnis- \ ) irwiillly. present** tly made. s usefully te finding i and lim. also dUdstory of cximately re demonution, or 1, or SO',, ilous, and gers were ;ger nails. m 'the an* purpose. _ rrentiati'T. e disease, raphic u\- elear eui as aimph*. i. dow- * UJ4/tatom ions to it. -impte case videncc f tted in the autopsy, sis prnl*the interas Is the that heavy j fields r mote fibncomraonly simulated Jtions than 10 fibrosis, raphic ap posure the with stub ' confusion. ' these ct`s, partirn* (jus inferinated no"* pulmotiao ion. .atment of. is receive :he t^st f'*A ly.;.. h`* ...ore in-* persons afV ts admins** `flP '^Vou 17, No. 5 * INDUSTRIAL MEDICINE ' Page U tmtion has not been observed to be attended by of many other substances. Which of these is i** injury, neither however, is there convincing evi- responsible has not yet been determined. In *>?dence that it has been of objective benefit to the presence of so much silica, this material can sSieotics. Nevertheless, many persons receiving. not be absolved, on the other hand rather sim 0r Trho have received aluminum for silicosis claim ilar lung damage has been reported from Ger ;C'subjective improvement many* in exposures In which aluminum at least '-^.v The status of aluminum as a therapeutic agent figured. xmoLETOS4 also reported case in Eng ^has not yet been determined. It seems to offer land in which exposure to aluminum was asso ^possibilities as a prophylactic, but as considerable ciated with lung changes. 4?time is still necessary to establish its usefulness, The inhalation of cadmium or cadmium com ;^no laxity in regard to recognized methods of dust pounds, either as fume or dust is attended by .^control should be countenanced. respiratory damage of a serious nature. In an .* Early In 1942 an occupational lung disease Ontario exposure 15 workmen from two plants r^rsew to this continent was discovered by ps. c. C. were injured in this way in 1933--two died. 'r-ySKAVER. Superintendent of a sanatorium situ- Dust is produced when the metal Is being '.Suited near St. Catherines, Ontario. A description ground or polished. Fumes are evolved during jfeji-of the disease and the circumstances which re* welding operations, or when the metal Is sub- revealed it has already been published.3 The de- . jected to high temperatures by accident, or for 4^tails need not be repeated. In the process in- the purpose of removing cadmium plate. Evolving bauxite, aluminum ore Is converted to When small quantities of cadmium are in ^corundum, a hard metal used in the abrasive In- haled, dryness of the throat, cough, a sense of hydostry. While the process is. In operation, the restriction in the chest, headache and vomiting ^attendant workmen are exposed to dense fames are produced. Heavy exposure is followed by .^f.from the materials being treated. severe lung changes, accompanied by marked ^* * The process is not new. It has been carried on dyspnea, persistent cough, cyanosis and prostra v-*?. for upward of 20 years in some of the plants tion, which may he prolonged. The disease has '-.^concerned, yet it was not previously Imowa to the characteristics of a chemical pneumonia, and injurious. This mar be explained on the this Is confirmed by postmortem findings. Con basis, either that in the past it did not occasion- valescence is apt to be protracted, but they even /J?ilung injury, or the disease was not recognized tually return to work without disability. ^.because its accompanying signs and symptoms In one instance radiographs were prepared -JcJwere ascribed to other causes. The latter is the during the acute illness. In this, the lung fields T^fmore probable. Early cases are symptom free, were seen to be occupied by intense nodular i3the signs, exclusively radiographic, are often so shadowing, closely resembling that to be observed Salight that they would be readily missed by one in certain cases of silicosis. Radiographic exam gr^not conversant with the situation and on the ination of the survivors of the affected was car sP^look out for them. Later eases as characterized ried out some years later. In none was there Li-^by `attacks of sudden extreme dyspnea and ehest evidence of any permanent lung Injury. .`Spain which have, on occasion, been interpreted as It was daring the war yean that beryllium ^^vindicating heart disease or pneumonia, poisoning was drawn to our attention.* Exposure Ay^r. The radiographic characteristics of the eon- to beryllium or to certain of its compounds is i^dition may be divided Into "early** manifesta- attended in certain individuals by skin troubles.* V^tions and "writ established** disease. The early It is also attended`by lung disease, often of a ^^manifestations are extremely slight They eon- serious nature. The disease has special-features: "Jurist of an indefinite granular appearance in the Symptoms may develop during exposure, or they ^tpiees with slight rather lace-like shadowing may be delayed, perhaps, for months or years "S-jWhicb appears in the sub*apical area and.which after exposure has ceased. Two types of the .^&'.may extend to the first interspace. As the eon- disease are recognized, an acute type and a de j$dition advances the lace-like shadowing is found layed. The acute form has characteristics which '^extending lower in the lung fields. A further ex- suggest a chemical pneumonitis. It results from Intension is accompanied by the loss of the lace- exposure to high concentrations of beryllium _'$rlike character of the shadowing. Eventually the compounds. It may be severe and even fatal, *^rhole lung field may be occupied by shadowing but in those who survive, the condition has a ^wfcieh has a rather granular, or even an irregular tendency to clear. The delayed form appears to ^hcdular appearance. have little relation to intensity of exposure. It "Sr Coincident with the peculiar lung shadowing is more apt to occur where relatively light, but 5itte diaphragm is generally markedly distorted. more prolonged exposure has been sustained.. A ** and the mediastinum, is widened. The "well es- feature of the delayed form is the occurrences'of ' tablished'* case is characterized by the occur- scattered granulomatous areas in the lung tis *.~t*nce of spontaneous pneamothoraces, very often sue which may undergo organization. In some > hi-Iateral. These occurrences are associated with cases the radiographic appearances closely re -the rather dramatic appearance of desperate semble sillcnris. it was therefore thought at one ' 'r.fiyspnea and severe chest pain. time that the disease might be a modified sili " The fume is the source of this lung damage. cosis. The etiology is still obscure. While in - It contains considerable quantities of very finely vestigating this matter, it was DR. cardner's* .`prided alumina and silica, and small amounts opinion that some other factor than beryllium Pag* 170 INDUSTRIAL MEDICINE Meg. lOi-'i might be involved. This apparently has sot ret bees established. Considerable data is befog collected and may serve to resolve the question. The dust of asbestos, a fibrous silicate, induces a lung fibrosis which may be disabling. The disease asbescosis differs considerably from sHicosis. Although areas of fibrous tissue develop throughout the lungs, these do not exhibit the nodular pattern that distinguishes that eondition. Radioiogically it is also different. Charac* teristically the heart shadow is shaggy, and the lung fields have a granular or "ground glass** appearance, but definite nodulation is sot appar- . eat Circulatory embarrassment is common is asbestosls. The disease however, does not appear to predispose to tuberculous Infections. Aside from asbestos, silicates are not usually related to lung injury. In this respect tale, a hydrated magnesium silicate, may be an exception. Although no clear evidence of injury has been produced in connection with persons handling talc, in many industrial operations such as tire building, paper making, etc^ injury has been demonstrated in relation to the production of this substance. Some years ago In Ontario the miners and millworkers from a small talc pro* during plant were surveyed. None of the miners showed radiographic changes suggesting disease, but examination of 37 mill men engaged in crushing ore discovered 13 in whom chest films gave evidence of lung fibrosis. The exposure periods in these cases were from five to 13 years, The average exposure was 12 years. The radiographic appearances were not uciform. In some, diffuse fine granular shadowing was seen throughout the lung fields. In others, nodular shadowing resembling but rather softer in character than that of silicosis was present, Several presented a combination of these appearances, with or without areas of massive shadoiving. Repeat examinations of many of those affeeted reveals that in none has there bees any clearing, but that several have progressed. The talc, a fibrous and flaky variety containing a small quantity of tremolite, occurs in fonnation consisting largely of crystalline limestone, In this formation numerous stringers of quart* are found. In the past, dust conditions in the mHZs were very bad, and great elouds of dust, visible from a considerable distance, could be seen escaping when crushing was in progress. Dust sampling was done in these mills. The samples varied considerably In silica content, depending on where they were co'lected. Air samples contained approximately 34% silica, and settled dust from the beams about 55%. Thu free silica content was estimated at 1% to 2%. It is evident that in 1943 siECAL7 and others encountered a situation somewhat similar to this In St. Lawrence County, New York. Doubts are entertained respecting the Ontario exposure. Having regard to dust conditions and the quartz in the limestone carrying the talc, the abnormal finding? may very well reflect a silicosis modified by other dust On the other hand, the matter of the extremely heavy dosage mast be considered. Although several of our cases have died, are have sot so far secured autopsy material. This is essential to a solution of the problem. * Certain lung conditions termed benign pneumoconiose*. of which siderosi* is an example are not infrequently encountered. These con* ditions are not in the least disabling and they do sot affect life expectancy. They arise in ra lation to occupations in which dust of metals or other Inert materials are produced. Particles of these materials opaque to the roentgen rays, on reaching the lung tissues are deposited-In re- latios to the lymphatics, where they remain inactive Causing no Injury, These conditions are not properly termed disease. I have referred to them merely because they may occasion radiographic appearances scarcely to be distinguished from those due to silicosis. It should be remembered however, that infectious processes may occur in persons with benign pneumoconiosis. In such cases the. Infection is .the disease to consider. Vow attention has been directed to a few -* dusts which are involved in the production of pulmonary' diseases, and certain characteristics of the disease they occasion, have been referred to. The subject has not been exhausted however: The connection between bagasse, sugar cane from which the sap has been extracted, and lung disease, should not be overlooked. Neither, should It be forgotten that dusts such as arsenic and those of certain radioactive materials have been related to the occurrence of neo-plastic lung conditions. You will recall that cotton workers are subject to an occupational disease, in which the materials they handle are in some way concerned, and that cotton dust may be involved, * We have in Ontario, plants in which the work era are in exposure to radioactive materials, arsenic and cotton. Most of the plants have medfoal departments, and x-ray surveys of the workfog staffs have been conducted from time to time, In spite of this careful supervision however, no convincing evidence has yet been forthcoming which would indicate that any of these materials are implicated in the causation of this type of lung Injury in Ontario. Complacence, especially in regard to occupational dusts of any nature, is always dangerous. Also new substances are frequently befog introduced into industrial operations, and older sub stances used In new ways and combinations. The result of these changes is often unpredictable, Constant vigilance is therefore necessary, Bibliography u a. j.: or--.v.a. *-:. tea. *. c. c- asi rw-ol a. k: j. m**:. * r#^- t~i. t. n. ***. s ere-i-Cu**! is: *** ***** \l: fc/ciiw**" m. V:. rr#r*w cw-> i*>? t*. * a., t-: a~. j * m. n.-i'-y.' if; ifi=- -- The America Ceramic Society February 15,1993 I hereby certify that the attached copies of.Ceramic Abstracts, Volume, 1948, 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. I cannot verify the accuracy of copies from Industrial Medicine, Volume 17,1948, \_iU13LUlC iPtIUUIXCl Product Manager Ceramic Information Center 735 Ceramic Place Westerville, Ohio 43081-8720 614*890*4700 TWX: 7101109409