208 EXPERIMENT STATION RECORD. 



Strength of the soap solution is modified accordingly. The method is claimed 

 to be more accurate than others because a dilute solution of soap and a burette 

 graduatal to tenths of a centimeter are used, quicker because no calculation is 

 necessary, and more modern because hardness is stated in terms of calcium 

 and not carl)()nate or oxid of calcium. 



Studies on direct Nesslerization of Kjeldahl digestates in sewage analysis, 

 G. O. Adams and A. W. Kimball (Jour. A»tcr. C'heni. »S'oc., 30 (1908), No. 6, 

 pp. lOS'i-lOSl ) . — A series of tests made to determine the merits of the claims 

 made for this method is reported. The conclusions reached are as follows : 



" The direct Kjeldahl method undoubtedly has its own place in sewage work, 

 but it does not seem as if it should take the place of the distillation method in 

 a permanent sewage laboratory handling many samples because of — 



"(1) The greater amount of bothersome and bulky apparatus necessary; (2) 

 the large amount of nitrogen-free water required; (3) the greater chance for 

 error in manipulation; (4) the necessity of having the excess of caustic within 

 narrow limits to avoid turbidity, this practically requiring a rough titra- 

 tion of each determination; (5) the gi-eater length of time required for the 

 determination. 



" The method, however, is without doubt an excellent substitute for the dis- 

 tillation method in a temporary laboratory where it is necessary to incur the 

 least possible expense for apparatus or in a small laboratory where but a very 

 few determinations are to be made daily." 



On the determination of nitrogen in gas mixtures, A. P. Lidoff {Atti 6. 

 Cong. Iiiteniaz. Chim. AppL, 1 (1906), pp. 35-3S, fig. 1). — The apparatus and 

 method used for this purpose are briefly described. 



Determinations of nitric acid in arable 'soils, M. Weibull (Svensk Kem. 

 Tidskr., 20 (1908), Nos. 1, pp. 11-13; 2, pp. 22-26).— X description and dis- 

 cussion of the phenoldisulphonic-acid colorimetric method of determining nitric 

 acid in soils. The method adopted by the author was that of Grand val and 

 Lajoux for determining small amounts of nitric acid in water,*^ modified for 

 use in soil analysis by G. Reitmair. 



Note on the Dyer method for the determination of plant food in soils, 

 F. T. Shutt and A. T. Charron {Jour, Amer. Chem. Soc, 30 (1908), No. 6, pp. 

 1020-1023). — In tests of modifications of Dyer's method on a prairie soil well 

 supplied with potash and nitrogen and containing fair amounts of phosphoric 

 acid and lime it was found that " reducing the period of digestion from 7 days 

 to 5 hours materially decreased the amount of phosphoric acid dissolved, but 

 did not similarly affect the potash — the percentages of the latter being prac- 

 tically identical for both periods. The lime falls off but slightly with the 

 shorter digestion. , . . Eeduciug the volume of solvent used, materially de- 

 creases the percentages of phosphoric acid and potash obtained. In the case of 

 lime, the smaller volume extracted but one-half that taken out by the larger 

 volume. Clearly, the influence of volume of solvent is decidedly greater than 

 that of the period of extraction." 



A new method for the quantitative determination of diastatic ferments, 

 J. Wohlgemuth {Biochem. Ztschr., 9 (1908), No. 1-2, pp. 1-9, pi. i).— A col- 

 orimetric method is described. 



The probable chemical constitution of rennet, A. Scala (Stas. 8per. Agr. 

 Ital., JfO (1907), No. 2, pp. 129-1. 'i9). — In the author's opinion renuin is a weak 

 base which consists of an albumose nucleus and amino-side-chains. Upon heat- 

 ing its activity is destroyed and its composition altered. A similar result is 



"Compt. Rend. Acad. Sci. [Paris], 101 (1885), p. 62; see also U. S. Dept. 

 Agr., Bur. Soils Bui. 22, p. 67. 



