924 



SCIENCE. 



[N. S. Vol. XIX. No. 494. 



A New Separation of Thorium from Cerium, 



Lanthanum and Didymium: Abthur C. 



Neish. 



Many organic precipitants were tried, most 

 of wliicli are weak organic acids. Metanitro- 

 benzoic acid was found to be the best and pre- 

 cipitated thorium quantitatively from a 

 neutral aqueous solution of the nitrate, while 

 cerium, lanthanum and didymium were not 

 precipitated. 



Tables were given showing the efficiency 

 of the separation from mixtures of pure salts 

 in the proportions usually found in monazite 

 sands. Five monazite sands from Brazil and 

 two from North Carolina were analyzed by the 

 new method and the results compared with 

 those obtained by the * combination ' and the 

 fumaric acid methods. 



The conclusions reached were: 



1. Metanitrobenzoic acid precipitates tho- 

 rium quantitatively as Th(0„H^]SrO„COJ^ from 

 a neutral solution of the nitrate. 



2. When the precipitation is repeated it 

 affords a complete separation from cerium, 

 lanthanum and didymium. 



3. This method gives as good results in the 

 analysis of monazite as does the ' combination ' 

 or fumaric acid method, and has the advan- 

 tage in that it is shorter and offers no diffi- 

 culties in precipitation or filtration, while the 

 precipitant is not expensive and avoids the 

 use of alcohol. 



A Crucible Charge for Gold and Silver in 

 Zinc Ores: E. J. Hall and E. Popper. 

 The well-known difficulties accompanying 

 the scorification assay of zinc ores, such as the 

 necessity of taking but a small portion for the 

 assay, the constant attention required, etc., led 

 to a series of experiments conducted with the 

 hope of eliminating both the troubles inherent 

 in any scorification as well as the special diffi- 

 culties met with in the scorification of zinc 

 blende. After various modifications of the 

 usual crucible charges had been tried, the final 

 charge decided upon was : 



Ore i/s A. T. 



Soda Ash li/a A. T. 



Litharge 25 gms. 



Borax Glass 20 gms. 



This charge was tried on fourteen ores 

 with results agreeing with or exceeding the 

 best figures obtained by scorification. A few 

 typical results follow: 



The charge is not applicable to ores contain- 

 ing more than Y per cent, of copper. The 

 proper temperature for fusion was found to 

 be from 750°-775° 0. and the time required in 

 the furnace 35 minutes. 



A New Crucible Support : W. E. Chamberlain. 

 Three pieces of pipestem are set radially in 

 a metallic ring or in the sides of an asbestos- 

 lined cylinder. The pipestem being movable, 

 the points on which the crucible rests may be 

 adjusted according to the size of the latter, and 

 the position in which it is to be held. 



Note on Milk Analysis: H. 0. Sherman and 



A. W. Hahn. 



The average results of many determinations 

 of fat and specific gravity in cow's milk were 

 shown and the following relations noted. In- 

 creasing richness in fat from 4.17 to 4.7 per 

 cent, was accompanied by increasing specific 

 gravity, but no corresponding increase of 

 gravity was found as the fat content increased 

 from 4.7 to 5.7 per cent. The percentage of 

 solids not fat (calculated by Eichmond's for- 

 mula) rose with the fat content, though to a 

 much smaller degree. The sum of the fat 

 content and the lactometer reading has been 

 proposed as a basis for the calculation of added 

 water in cow's milk, with the claim that it is 

 a more constant figure in normal milk than the 

 percentage of solids-not-fat. According to the 

 results presented, the solids-not-fat is the 

 more constant figure of the two, and is, there- 

 fore, to be preferred as a criterion of water- 

 ing or a basis for calculating the amount of 

 water added. 



H. C. Sherman, 



Secretary. 



