1010 EXPERIMENT STATION RECORD. 



bis studies that exact lueasuremeut of citral in lemon grass is not possible. 

 Scliimmers process gives only the relative value of the essential oil. The cleter- 

 miuatious should always be made under the same conditions of time and tem- 

 perature. The value taken should be the average of 4 to 6 tests, and a margin 

 of from 2 to 3 per cent is allowable in averaging the results obtained. 



Detection of citric acid, G. Favrel (Bui. Soc. Sci. Nancy, 3. scr., 8 {1901), 

 ISO. 2, pp. 2JfO, 2-'fl). — The method described is based upon the decomposition of 

 citric acid by concentrated sulphuric acid. 



Detection of hydrogen peroxid in milk, E. Fedeb (Ztschr. UntcrsucJi. Xalir. 

 u. GciiiissintL, 15 (1908), No. J/, pji. 23'i~2-36). — When a drop of weak formalin 

 solution is added to 5 cc. of milk containing 0.10 per cent or more hydrogen 

 peroxid, and 5 cc. of concentrated hydrochloric acid is added, a blue-violet 

 color appears on heating at 60° for a few minutes. 



Judging- the purity of butter fat, H. Luhrig and A. Hepner {Pliarm. 

 Zentralhalle, JjS (1907), Nos. 51, pp. 10'i9-105G; 52, pp. 1067-1072) .—Cream 

 from mixed milk from a large herd of cows was made into butter and various 

 chemical and physical constants were determined, including those ordinarily 

 reported, such as the Keichert-Meissl number, saponilication number, iodin 

 number, etc., and others recently suggested, as the capryllic acid value- accord- 

 ing to Dons, the baryta value according to Ave-Lallemant, and others. 



Data are given for IS samples collected during a period of feeding with beet 

 leaves. The authors believe that the experiments were made under conditions 

 that show the effect of the feed on the analytical constants of butter fat. The 

 Reichert-Meissl number was not affected, but the saponification number of the 

 fat and that of the nonvolatile fatty acids were increased. Some of the other 

 constants were also more or less affected. 



Determining the water content of butter, H. Faber (Milchw. Zentbl., Jf 

 (1908), No. 1, pp. 7-12). — Various methods are described and compared. 



Estimation of saccharose in bagasse, H. C. P. Geerlics (Mcdcd. Procfstat. 

 Jai-a-Suikcrindit.s., 1908, No. 7, pp. 201-212). — A study of methods. 



The use of the Abbe refractometer for determining the dry substance of 

 sugar solutions and raw sugar, A. E. Lange (Ztschr. Vcr. Dcut. Zuckenudus., 

 1908, No. 626, II, pp. 177-198, fiys. .'/).— A study of the conditions under which 

 this method may be employed is reported in detail and leads to the general 

 conclusion that it is easier to estimate the dry substance of sugar juices by 

 means of the Abbe refractometer than by determining the Brix index or by 

 means of a spindle or a balance, and that the results of the former method 

 are nearer the true values than those by the latter except in the case of impure 

 sugar solutions or raw beet juices. 



Extracts from the proceedings of the Association of Official Agricultural 

 Chemists, 1907 (U. S. Dcpt. Agr., Bur. Cheni. Circ. 38, pp. l-'f). — This contains 

 the reports of the committees on recommendations of referees, resolutions, 

 amendments to the constitution, unification of terms for reporting analytical 

 results and revision of methods, with the action taken by the association in 

 each case, together with a list of the officers, referees, and conmiittees for the 

 year 1908. 



METEOROLOGY— WATER. 



The evaporating power of the air at the New York Botanical Garden, 

 C. S. Gager (Jour. N. Y. Bot. Gard., 8 (1907), No. 96, pp. 269-27-',. fin. /).— 

 Observations from June 10 to September 23, 1007, at 3 stations differently 

 situated in the P.otanical (Jarden are reported. The observations were made 

 with a special form of evaporimeter which was devised for an extended investi- 

 gatiou ou evaporation tlirougliout the Uuited States, of whicli tliese observa- 



