proceedings: chemical society 87 



The 234th meeting was lield on Thursday, January 8, 1914, at the 

 Cosmos Club. The president appointed the following committees: 

 Committee on Communications: H. C. Gore, Chairman, A. Seidell, 

 E. C. Shorey, W. Blum, and J. Johnston. Entertaiimient Committee: 

 A. N. Finn, Chairman, J. G. Riley, J. W. Turrentine, E. A. Inger- 

 soll, and J. C. Hostetter. The Secretary's and Treasurer's reports 

 were read. 



Dr. William Duane of Harvard University was presented by the 

 chairman, and spoke briefly and informall^^ on radium and the radium 

 emanation, shomng samples of both and illustrating their effect in pro- 

 ducing phosphorescence in willemite. 



The papers on the regular program were as follows : 



L, F. Kebler, of the Bureau of Chemistry: Chemical investigations 

 in tablet medication. Medication by tablets has so many advantages 

 that it has come into wide use, altho the invention is of comparatively 

 recent date (1843). The speaker sketched the history of the patents 

 and the development of modern rapid machinery for making various 

 types and forms. A study has been made of the variations in Aveight of 

 various tablets due to the kind of machine used. A variation of not 

 over 2 per cent in the number made from a batch of given weight is 

 claimed for some machines and materials. Satisfactory tablets should not 

 vary more than 10 per cent. Fifty-four kinds of tablets made by single 

 punch machines showed 44 per cent exceeding a 10 per cent total weight 

 variation, and the rotary machine gave nearly the same results. The 

 tablet triturates however showed best results by the single punch ma- 

 chine. Molded tablets (compressed by hand) showed 79 per cent -with 

 a total weight variation of 10 per cent or over. Variations in composi- 

 tion as determined by analysis (324 samples, 449 analyses) sometimes 

 ran very high, 20 to 40 per cent variations, (usually below declaration) 

 being fairly common. Nitroglycerin tablets showed the widest variation. 



Discussion: In reply to inquiries by Yoder and Foster, it was stated 

 that the filling of the molds is by volume only, and that each of the 

 analyses reported on represents from 10 to 25 tablets as a sample. 



Wirt Tassin: Metallography applied to inspection. Failures of engi- 

 neering structures whose members have passed all ordinary tests on sample 

 pieces have frequently occurred, and have been usually laid to "fatigue" 

 of the material due to repeated stresses. The failure of test pieces 

 really to represent the properties of the structural member is becoming 

 recognized as a frequent cause. The speaker described improvements 

 in the apparatus which he exhibited before this Society at the meeting 

 of February 13, 1913, and which is now being regularly used for examin- 

 ing directly large structural pieces in the foundry or shop. Slides illus- 

 trating the effects of various heat and mechanical treatments were shown 

 and discussed. 



Robert B. Sosman, Secretary. 



