CHEMISTRY. 307 



tnil, })oiliiit4% coiK-eiitrated solution of ammonium chlorid a regular dis- 

 engagement of nitrogen takes place aoeording to the following formula: 

 NH,a+N02M' = N, + 2H,0+]\rCl. The nitrite is estimated either 

 from the amount of nitrogen given oti' or of anunonunn ehlorid decom- 

 posed. The author considers the former method preferable. He uses 

 for the collection and measurement of the nitrogen a modification of 

 Schloesing's apparatus for the determination of nitrates. 



The distillation of ammonia in the determination of nitrogen, 

 F. G. Benedict {Jour. Amrr. ChriH. Sor., 22 {1000). A<>. ■'>, pp. 2o0- 

 263., fig. 1). — The essential feature of the method proposed consists in 

 distilling the liquid through a condenser surrounded by cold water, 

 which is allowed to i"un out a few minutes before the end of the dis- 

 tillation, so that the condenser tubes may become heated and the 

 ammonia driven out of them b}' a current of live steam. In this waj^ 

 about 20 minutes"' distillation suffices to drive over all of the ammonia. 

 A form of distillation apparatus adapted to this method is described. 



Lime and sulphuric acid by the photometric method, J. I. D. 

 Hinds [Jour. Amer. Chan. Soc, 22 {1900), J^o. 5, pj). 269-271^).— In 

 this method (E. S. R., 8, pp. 201, 202) lime is precipitated in the solution 

 to be tested with solid calcium oxalate and sulphuric acid with solid 

 barium chlorid. A cylinder 3.. 5 cm. wide and 20 cm. high, graduated 

 in centimeters and millimeters, is held over a sperm or wax candle and 

 the water containing the precipitate is poured into it until the image 

 of the flame just disappears. The depth in the cjdinder is read and 

 the percentage is calculated from ecjuations or read from tables which 

 are given in the article. 



The estimation of fat in s'weetened condensed milk by the Bab- 

 cock test, E. H. EARKiNCiTON {Amer. Chem. Jour.., 22 {1900), Avy. 3, 

 Ip. 267-270). — In testing sweetened condensed milk by the Babcock 

 test the excess of cane sugar causes a poor separation of the fat, pre- 

 venting a satisfactory reading. The author finds that the sugar can be 

 washed out without removing any of the fat. In making the test, 

 preferably 60 gm. of condensed milk is dissolved in 100 cc, of water, 

 the volume made to 200 cc, and 17.0 cc. of this solution mixed in a 

 Babcock test bottle with about 3 cc. of the sulphuric acid commonly 

 used for testing milk. The bottle is whirled for al)out minutes in a 

 turbine centrifuge heated to about 200° F., in order to compact the 

 curd into a iirm lump. The whey containing the sugar is poured oflf, 

 10 cc. of water added to the curd and 3 cc. of acid, and the whirling 

 repeated. After pouring ofi' the Avhey a second time the curd is mixed 

 with 10 cc. of w^ater and 17.5 cc. of sulphuric acid, and the test then 

 made as usual. "Careful tests of the whev poured oH' from the test 

 bottles showed that no fat Avas lost 1)v this decantation if the whey was 

 clear and contained no pieces of curd." The results of tests of a num- 

 ber of samples by this method are reported. 



