314 EXPERIMENT STATION RECORD. [Vol.35 



which the burette and leveling bulb are mounted together on a Woulff bottle, 

 and its manipulation are described in detail. 



A simple, efficient, and econom,ic filter, S. L. Jodidi and E. H. Keixogg 

 (Biochem. Bui., 5 {1916), No. 18-19, pp. 87-94).— The authors describe in detail 

 the preparation and use of the paper pulp filter and demonstrate its efficiency 

 by submitting analytical data. Its application to the filtration of the ammonium- 

 phosphomolybdate precipitate in phosphorus determinations is especially indi- 

 cated. 



See also previous notes (E. S. R., 34, p. 712; 35, p. 204). 



A modification of the Lung-e nitrometer, W. Senften (Chem. Ztg., JfO {1916), 

 No. 4-5, pp. 39, 40, figs. 2). — A modified apparatus, which shortens the time for 

 making determinations by insuring the complete solution of the sample, and its 

 manipulation are described in detail. A new gas burette for use in connection 

 with the apparatus is also described. 



The quantitative determination of silica, V. Lenher and E. Tetjog {Jour. 

 Amer. Chem. Soc, 38 {1916), No. 5, pp. 1050-1063). — After preliminary experi- 

 ments on the various factors which influence the solubility of silica the follow- 

 ing procedure was adopted : 



A 0.5 to 1 gm. sample is intimately mixed with 5 gm. of sodium carbonate 

 and fused in a platinum crucible. The cold fusion is treated with 60 cc. of 

 hydrochloric acid (specific gravity 1.07). After all carbonates are decomposed 

 the solution is evaporated on the water bath until the residue begins to crumble. 

 The residue is treated with 15 cc. of hydrochloric acid (specific gravity 1.1), 

 covered, and heated on the water bath for ten minutes. After diluting with 

 10 cc. of water it is filtered and the silica washed with a hot solution consisting 

 of 5 cc. of hydrochloric acid (specific gravity 1.2) to 95 cc. of water. The 

 filtrate is evaporated to dryness, the residue dehydrated at 110° G. for two 

 hours, taken up with 8 cc. of hydrochloric acid (specific gravity 1.1), covered 

 and heated on the water bath from five to ten minutes, diluted to 50 cc, and 

 filtered immediately, washing with cold water containing 1 cc. concentrated 

 hydrochloric acid to 99 cc. of water. The two portions of silica thus obtained 

 are carefully ignited to constant weight in a platinum crucible and the silica 

 determined by volatilization with hydrofluoric acid after the addition of a few 

 drops of sulphuric acid. 



It is indicated that in the sodium-carbonate fusion methods for silicates there 

 is always a nonvolatile residue which contains the various bases and which 

 should be fused again with sodium carbonate and added to the filtrate from 

 the silica when the bases are to be determined. 



Dehydrated silica is appreciably soluble in hydrochloric acid of all strengths. 

 This error is, however, negligible when dilute acid is used. The dehydration 

 temperature should be kept below 110°. Excessive amounts of sodium car- 

 bonate should be avoided in the fusion, since the subsequently formed sodium 

 chlorid exerts a solvent action on the silica. 



Comparative tests of certain methods for the determination of copper in 

 copper sulphate, von Wissell and F. Ktjspekt {Landic. Vers. Stat., 86 {1915), 

 No. 3-4, pp. 277-286). — As a result of the comparison of the various methods 

 used for the determination of copper in fungicidal materials in the presence 

 of iron the thiocyanate procedure was found to yield reliable results and to 

 be the simplest and most economical of all the methods tried, especially where 

 only occasional determinations are necessary. 



The Grete volumetric method for the determination of phosphorus in ferti- 

 lizers, G. Inoze {Kis^rlet. Kozlem., 18 {1915), No. 5-6, pp. 797-809). — From a 

 critical exa3BiHation of the method the author has found that the proper prep- 



