AGRTfTTLTLTKAL CHEMISTRY. 709 



speed of reaction was perhaps ^I'eater at hi,t?her temperatures, but equilibrium 

 was iu all cases repidly readied. 



The most complete conversion of allcali to hydroxid (98.1 to 0!).l per cent) 

 was obtained in case of normal solutions of alkali carbonates at 100° C, the low- 

 est (abeut 92 per cent) with thrice-normal alkali carbonate, which was th(; 

 strongest sokition used, the results with twice-normal carbonates being inter- 

 mediate. 



Determination of formaldehyde in milk, F. W. Rich.\rdson {Jour. Soc. 

 ('Item. Indus., 26 (1907), No. 1, pp. J. ',).— This is a ])reliininar.v note on efforts 

 being made by the author to devise a method for the «iuautitative determination 

 of formaldehyde in milk and other materials. 



Sulphuric acid containing 0.05 per cent of ferric sulphate is added drop by 

 drop to 5 cc. of milk in a porcelain dish with vigorous stirring after eat^h 

 addition. The liquid so obtained may be diluted with a mixture of sulphuric 

 acid and water in equal parts in order to make color comparisons in glass cells 

 by Lovibond's system. F>y this means the author estimates colorimetrically 

 0.002 mg. of formaldehyde. 



In determining foriiuildehyde in aqueous solutions by this method it is neces- 

 sary to add some albuminoid substance, and tests are being made to determine 

 which will give the deepest color. Other nitrogenous bodies than albumoses 

 liav(> been found to give this reaction. 



The estimation of preservatives in milk, H. S. Siikewsbury {Analyst, 32 

 (1007), Xo. 370, pp. 5-l.'i). — Tests of methods for the determination of formal- 

 dehyde and boric acid in milk are reported. 



A new apparatus for the rapid and accurate determination of the fat con- 

 tent of milk, J. Adorjan {ZtscJir. Landir. Vcrsiiclisiv. Oslcrr., 9 {19(16), \<>. 

 12. pp. 1063-1066, fiff. 1). — A moditication of the Gottlieb apparatus is described. 



A simple fat extraction apparatus, G. S. Fraps {Amer. Chein. Jour., 37 

 {1907), No. 1, pp. 85-87, fiff. 1). — The author describes this mercury sealed ap- 

 paratus as having some points of resemblance to Knorr's, but being much simpler 

 in construction and less exi)ensive. 



Detection of the adulteration of butter with cocoanut oil and oleomargarin, 

 L. Koiux {Ann. Chiiii. .\iniJiit., 12 {1907). No. 1. pp. 1 ), l'>). — Applying methods 

 to which reference has already been made (E. S. R., 18, p. -119), the author finds 

 that dividing the index of saponification of pure butter by the percentage of 

 fatty acids soluble in water gives a quotient in no case exceeding 39. The same 

 procedure applied to margarin gave 1,791, to cocoanut oil figures varying from 

 129 to 142, and to mixtures of butter and 10 per cent of margarin or cocoanut 

 oil figures above 39 in 48 out of 50 cases. 



On the detection of cotton-seed oil, N. Petkow {Ztsclir. Offeiitl. Chem., 13 

 {1907), No. 2, pp. 21-25). — Studies were made of the Ilalphen and Becchi re- 

 actions. 



The two reactions are not believed to be dependent upon the same substance. 

 The sensitiveness of the Becchi reaction depends upon the relative ;imount of 

 the silver nitrate solution used. The two tests are considered necessary in 

 determining the presence of cotton-seed oil, inasmuch as certain samples do not 

 respond equally well to both tests. The colorimetric determination of the per- 

 centage of cotton-seed oil in mixtures with other oils is considered uncertain as 

 the color of the Halphen test with different cotton-seed oils is not uniform. 



Determination of sucrose and of reducing sugars in fluid saccharin prod- 

 ucts, F. G. WiECiiMANN {Jntermf. Su</ar Jour.. 9 {1907), No. 98, pp. 68-77).— 

 In view of results obtained in his investigations of the determination of sucrose 

 and reducing sugars in fluid saccharin products, the author recommends for 

 this purpose the retention of the present composition of Fehling's solution, 



