BUREAU OF CHEMISTRY. 233 



PAPER AND FABRICS. 



Assistance in the preparation of specifications for paper has been 

 given to the congressional Joint Committee on Printing, to the Post 

 Oflice Department, and to the Treasury Department. 



The study of the waterproofing, mildewproofing, and fireproofing 

 of fabrics for farm use has been continued. A farmers' bulletin on 

 waterproofing and mildewproofing for farm purposes, as well as an 

 article on the general toxicity of soaps of heavy metals, alone and in 

 combination, to fungi occurring on textiles, are in preparation. A 

 paper entitled "Water Resistance of Fabrics" is in press. 



Assistance has been given to the Office of the Quartermaster Gen- 

 eral and to the Chief of Staff of the Army on the preservative treat- 

 ment of fabrics and on the repairing and waterproofing of tentage. 



METHODS AND APPARATUS. 



Methods have been published for the estimation of theobromin, 

 of potassium guaiacol sulphonate, of citral, of mercury precipitated 

 as mercuric zinc thiocyanate, of zinc precipitated as zinc mercury 

 thiocyanate, of copper in insecticides, of zinc and copper in gelatin, 

 of tyrosine in proteins, of the loosely bound nitrogen in eggs as am- 

 monia, of the lower alkylamines in the presence of ammonia, of 

 coumarin in factitious vanilla extracts, of iodin in mineral waters 

 and brine, and of the acidity of grain extracts. Report has been 

 made upon the use of benzaldeh^'de sulphite compound as a standard 

 in the quantitative separation and estimation of benzaldehyde and 

 benzoic acid, upon a method for the rapid analysis of mixtures of 

 chlorinated toluene, and upon the use of thymosulphophthalein as an 

 indicator in acidimetric titrations. 



Methods ai*e in process of publication upon the determination of 

 biomid in mineral waters and brines, the estimation of monobro- 

 mated camphor in migraine tablets, the use of kaolin in tannin 

 analysis, the determination of water solubles in leather, the deter- 

 mination of caffeine, and the determination of the water resistance 

 of fabrics. Certain other investigations upon analytical methods are 

 referred to elsewhere in this report. 



Descriptions of laboratory apparatus for rapid evaporation, and 

 of a new type of volumenometer have been published. 



The bureau's machinery for the examination of supplies purchased 

 has been reorganized, and a paper on the general subject of labora- 

 tory apparatus was presented to the American Chemical Society. 



ANALYTICAL WORK FOR OTHER DEPARTMENTS. 



For other executive departments and Government establishments, 

 17,392 samples were analyzed. This is a larger number than normal, 

 due to the fact that the various war agencies called upon the bureau 

 for much analytical work in the purchase of war materials, particu- 

 larly food, drugs, and leather. While it is not probable that the 

 number of samples analyzed for other departments and war agencies 

 will be as large in subsequent years, the indications are that it will 

 be noticeably larger than before the war, since many of the Govern- 

 ment agencies have found that a chemical test of materials purchased 

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