610 EXPERIMENT STATION RECORD. 



On the equilibrium weights of ammonia, F. Josr {Ztscln: Aiioigan. Chem., 

 51 U'JOS), Ao. /,. PI,. 'iL'i-JiSO, fig. 1; Ztschr. Elektrochcin., JJ, (I'JOS), No. 2S, 

 pp. 313-315; <ihs. in Set. Ahs., Sect. A—Pkys., 11 (1M8), No. 129, pp. 531, 

 538). — 2s'e\v measurements with the Nernst electric pressure furnace of the 

 partial pressure of ammonia formed from nitrogen and hydrogen are reported. 

 The conchisions of Ilaber and Le Rossignol are criticised. 



On the constitution of phosphoric acid, F. C. Palazzo and F. Maucuacomo 

 (G'fl.c. CJiiiit. Itah, 3S {l!)OS). II. \o. .2. pp. 115-123).— \ theoretical discussion. 



The determination of phosphoric acid, N. von Lorenz (CJirin. Ztg., 32 

 (1908), yo. (iO. pp. 101-lOU; (ihs. in Chcm. Ah>i.. 2 (JH08). .Yo. 20, p. 21U1).— 

 From a comparison of his method with the citrate method the author concludes 

 that while the accuracy of the latter depends upon a compensation of errors 

 the former gi^es directly accurate results. The author's method, moreover, is 

 quicker, moi-e convenient, more generally applicable, and does not require the 

 previous removal of silica. 



The determination of phosphoric acid by the von Lorenz method, O. 

 Fallada (Mitt. Ctiem. Tech. Vers. Stat. Vent. Vcr. Riihcnz. Indus. Osterr. 

 Ungar., No. 202. pp. 1-10; ahs. in Chem. Zenthh, 1908, II. No. 9. pp. 821, 828).— 

 Comparative tests of this method and of the Wagner molybdic and citrate 

 methods on Thomas slag, spodium. and superphosphate are reported. The 

 results indicate a high degree of reliability for the method. 



Action of ammonium, citrate on calcium phosphate, A. Barille (Jour. 

 Pharm. et Chim.. 6. ser., 21 (1908). No. 9. pp. .'i31-'i-',J ; Ann. Chim. Analyt.. 

 13 (1908), No. 1. pp. 261,-266; ahs. in Jour. Chem. Soc. \Lon(lon\. 9', (1908). 

 No. 548. II, p. Ji96; Chem. Zenthh, 1908. I, No. 26, />. 2130; Chem. .ihs., 2 

 (1908). No. 11. p. 235'/). — Experiments with dicalcium and trlcalcium phos- 

 phates show that both salts are soluble and that the solubility varies with their 

 physicial condition. The author concludes that the ammonium citrate solution 

 not merely dissolves the phosphates, but forms true double salts with them. 



A simple method for the determination of potash in silicates, W. Autkn- 

 RiETH (Zenthh Min. «. Geoh, 1908, pp. 513-511 ; ahs. in Chem. Zenthh. 1908, IT, 

 No. IS, pp. 1125, 1126; Chem. Ahs., 2 (1908). No. 22, p. 3038; Jour. Chem. Soe. 

 ]Lon(lon'\, 9', (1908). No. .5-52. II. p. 8.97).— The silicate is reduced with hydro- 

 fluoric acid and sulphuric acid. The potash is precipitated with Koninck's 

 sodium cobalti-nitrite reagent, but finally converted into either chloroplatinate 

 or pei'chlorate and so weighed. 



A short volumetric method for the estimation of sulphuric acid, T. CooK- 

 SEY (Jour, and Proc. Roy. Soc. N. S. Wales. J,l (1901), pp. 216-218).— A 

 method based upon " the volumetric estimation of the excess of barium chlorid 

 left in solution after precipitation of the sulphuric acid as sulphate of baryta " 

 is described. 



Mechanical and physico-chemical analysis of soil, F. Hiti (Estac. Ayr. 

 Cent. [.1/ejr/rol Boh '/. pp. 10). — The methods proiiosed by Grandeau for this 

 purpose are described. 



The estimation of phosphoric acid in foods, E. Worner (ZtscJir. Untersucli. 

 Nahr. u. Genusxmth, 15 (1908). No. 12. pp. 1.32-13.'i). — In the method described 

 by the author the food material is oxidized with nitric and sulphuric acids, the 

 phosphoric acid precipitated with molybdate solution, and the precipitate 

 heated with excess of standardized sodium hydroxid solution. Ammonia is thus 

 expelled and its quantity as determined by titration is a measure of the phos- 

 phoric acid jiresent. 



The detection of pentoses by means of orcin hydrochlorate, .T. Pierakkts 

 (Buh A^ssov. Chim, Suvr. vt Distilh, 26 {1908), No. 1-2, pp. ',6-62) .—ThQ results 



