308 EXPERIMENT STATION EECOKD. 



with dilute sulphuric acid and burn at a temperature below red heat. Digest 

 the ash in dilute hydrochloric acid and filter ; bring the filter paper and residue 

 to dryness in a platinum dish, ignite, digest in hot water, filter, and add the 

 filtrate to the one resulting from the first ignition; make the solution up to 

 volume, and take for the determination such aliquots as will represent 2 to 4 

 gm. each of the fresh substance. 



"Precipitate the phosphorus with magnesia mixture and 10 cc. of ammonia. 

 Allow to stand over night and filter. Evaporate the filti-ate to a low volume, 

 transfer to a platinum dish, bring to dryness, and continue heating on a sand 

 bath until ammonia fumes are evolved; then bum off all ammonium salts 

 over a flame. Take up the residue in the platinum dish" with hot water, trans- 

 fer to a beaker, and heat; then add enough freshly prepared barium hydrate 

 solution completely to precipitate the magnesium. Let the precipitate settle for 

 a few minutes and test for complete precipitation. When no further precipita- 

 tion is produ(5ed, filter and wash thoroughly with hot water. Heat the filtrate 

 to boiling, make alkaline with ammonia, and add ammonium carbonate to pre- 

 cipitate the barium, calcium, etc. Filter, add a drop or two of hydrochloric 

 acid and 1 cc. of ammonium sulphate solution (75 gm. per liter) and digest for 

 several hours on a steam bath. Transfer into a platinum dish, evaporate to 

 dryness and ignite; dissolve in hot water and filter into a weighed platinum 

 dish, in which evaporate, ignite, heat to constant weight, and weigh as sodium 

 and potassium sulphates." 



Some results of comparative tests with the new and ofiicial methods are in- 

 cluded, which were made with distillers' grains, snakeweed, cotton-seed meal, 

 and brewers' grains. 



The method for crude fiber has been previously noted from another source 

 (E. S. R., 29, p. 506). 



The estimation of carbon dioxid in water, J. Casaees and S. Fina (Abs. in 

 Chem. Ztg., 36 (1912), No. 13, p. 6SS).— In numerous tests with sodium car- 

 bonates in solutions of known concentration of carbon dioxid, the average 

 error was 6 times larger than that reported by Winkler. Tests with diluted 

 sodium carbonate solutions gave errors up to 50 per cent, so that the method 

 can be considered only approximate, and is of no value for solutions containing 

 small amounts of carbon dioxid. 



Detection of saccharose in various branches of analytical practice, S. Roth- 

 ENFUSSER (Ztschr. UntersHch. Nahr. u. Genussmtl., 24 (1912), No. 9, pp. 558- 

 570). — This is a discussion of the author's method (E. S. R., 22, p. 10) for de- 

 tecting saccharose in must, wine, beer, milk, cream, honey, infant foods, bakers' 

 goods, and color malt. 



About a method for determining tartaric acid in the presence of metals 

 which may form complex salts, A. Kling and D. Florentin (Orig. Commun. 

 8. Intcniat. Cong. Appl. Chem. [Washington and New York^, 1 (1912), Sect. I, 

 pp. 237-2Jf9; ahs. in Chem. Ztg., 36 (1912), No. 134, V- 1301).— In work previ- 

 ously reported (E. S. R., 23, p. 418) the senior author proposed a method in 

 which the tartaric acid is precipitated as calcium racemate. This is practically 

 insoluble in water and dilute acetic acid, but easily soluble in dilute mineral 

 acids. 



If to an alkaline tartrate or dextrorotatory tartaric acid (which is the only 

 form which occurs in nature) an excess of ammonium tartrate is added, and 

 then some calcium acetate, the entire tartaric acid is precipitated as dextro- 

 rotatory calcium racemate. It is of course necessary that there be no free 

 mineral acid in the solution. As the precipitate always takes with it a certain 

 amount of levorotatory calcium tartaric, it is necessary to redissolve it; ancj 



