AGEICULTURAL. CHEMISTRY AGROTECHNY. 509 



energies are also classified in a siiuilar niaiiner, A. K. icpreseiitiiij; the amiuoui- 

 fication efficiency, A. I. P. the ammonifying inoculating power, and A. C. the 

 ammonifying capacity. 



Methods for determining these indexes are appended. They consist chiefly in 

 judging the action of the micro-organisms of the soil upon ammonium sulphate, 

 and determining the end products, nitrates, nitrites, and anunonia in the media, 

 taking into consideration the nitrates, nitrites, and ammonia originally present 

 in the soil. 



A rapid method for the determination of total potassium in soils, O. M. 

 Shedd (pp. 38-42). — Further tests with a method previously noted (E. S. R., 21, 

 p. 209) are presented. 



Some investigations coneerning the keeping qualities of sugar sirups, fruit 

 sirups, and crushed fruits, H. E. Barnard (pp. 66-71). — This study has particu- 

 lar reference to the keeping quality of soda fountain crushed fruits and fruit 

 sirups. The tests were so carried on as to simulate as nearly as possible the 

 conditions as they exist in soda-water establishments. 



" The results briefly summarized indicate, first, that concentrated crushed 

 fruit and fruit sirups may be kei)t without loss for from 1 to 3 months after 

 opening, when held at a temperature below 50° F. ; second, that fountain sirups 

 made with 14-lb. sugar sirup will keep from 2 to 4 weeks without the slightest 

 evidence of fermentation; third, that crushed fruit concentrates diluted with 

 sugar sirup of 14 lbs. to the gallon will keep when exposed at room temperatux-e 

 from 3 to 10 days, and when such goods are placed in the refrigerator of the 

 fountain during the night for a period of 8 hours the time during which they 

 keep in good condition is nearly doubled; fourth, the keeping quality of crushed 

 fruits and fruit sirups is influenced materially by the concentration of the sugar 

 solutions used as diluents." 



Distinction of vanilla extract and its imitations, A. L. Winton and C. I. 

 Lott (pp. 109-112). — The authors draw attention to the fact that utilizing sub- 

 acetate of lead for estimating the lead number with dealcoholized solutions car- 

 ries down some of the vanillin and thus makes it impossible to determine 

 vanillin, coumarin, and the lead number in one weighed portion. When normal 

 lead acetate is substituted for the basic salt much of this error is eliminated, 

 and when used according to the process given by the authors permits the 

 determination of vanillin in the filtrate. 



Determination of starch in cocoa products, W. L. Dubois (i^p. 1.S6-138). — 

 The author recommends a rapid shaking out method instead of the tedious and 

 sometimes inaccurate provisional method of the association for estimating the 

 fat in cocoa and chocolate powders. 



An accurate method for hydrolyzing starch in unsweetened cocoa and choco- 

 late products, with which it is not necessary to remove the fat before going on 

 with the determination, is also given as follows: "Two gm. of the .sample 

 are transferred to a .500 cc. Erlenmeyer flask, 20 cc. of water added, and then 

 12 cc. of concentrated sulphuric acid, the latter cautiously and with slow rota- 

 tion of the flask. The mixture is heated over a low flame [for approximately li 

 minutes] with constant rotation until the color changes from brown to reddish 

 black. Thirty cc. of water are then added, the mixture is heated to boiling, 

 and boiled for 15 seconds. A little cold water is pouretl in, the flask quickly 

 cooled, and the acid nearly neutralized with a saturated solution of caustic 

 potash. The solution is then again cooled and transferred to a 2.50 cc. flask, 

 completing to volume with cold water. Fifty cc. of the filtrate are used for the 

 determination of copper-reducing substance as dextrose." 



