CHEMISTRY. 1005 



the solution is lilt(M"('fl throug'li a (toocIi crucible, washed with alcohol 

 coiitaiuino- perchloric ai-id until the washings amount to 60 to 7U cc, 

 then with a few cubic centimeters of 90 per cent alcohol. The crucible 

 is dried in the air bath for 20 to 25 minutes at 120 to 180'^ C, then 

 washed with hot water, dried, and weighed again. The diti'erence in 

 the two weighings gives the amoiuit of pure potassium perchlorate. 

 From this the potash may be calculated by the factor .8402. The 

 results by this method were found to be, on an average, 0.258 per cent 

 lower than those o])tained l)y the platinum chloi-id method. 



A method for preparing normal, seminormal, decinormal, etc., 

 sulphuric acid of exact strength, R. K. Meadp: {Jour. Arner. Chem. 

 Soc, 2J {1001), No. l,pp. 7,.^-7J).— The method of Hart and Croasdale 

 of making a standard £>ulphuric acid solution bv the use of the electric 

 current was found by the author to be accurate, and needs no checking 

 except against errors of manipulation. By this method the electric 

 current is passed through a solution of copper sulphate. The salt is 

 decomposed, the sulphuric acid sepai-ating at the anode and remaining 

 in solution. Very accurate results were obtained in making standard 

 acids of various strengths. 



A very delicate reaction for determining the presence of for- 

 maldehyde and of milk sugar in milk, E. Kieglek (P/^^<;v/i. Central 

 Inillr^ '/) {1000). j>2>. 700, 770; ahs. in Chem. Centhl., 1001, /, No. 3,2). 

 "206). — In testing milk for formaldehyde, phenylhydrazin and a 10 per 

 cent solution of soda is added to a small portion of the diluted milk. 

 In the presence of even 2 drops of formaldehyde to 10(» cc. of milk, 

 a rose color will result. In normal milk no color is produced. In 

 determining the presence of milk sugar, a small amount of sodium 

 acetate is added in addition to phenylh3'drazin and lo per cent soda 

 solution, as in the previous case. A rose color will result in the pres- 

 ence of milk sugar. 



A note on the examination of butter and other fats, A. Keychler 

 {Pyiil. Soc. Ch'nn. Paris,.!, ser.,25 {1001), No. 2, pp. 7^^-74^).— Compari- 

 sons are made between the total volatile and the volatile and soluble 

 fatty acids of butter, cocoanut oil, oleomargarine, neutral lard, and 

 mixtures of the same. These results are presented in a ta1)le. and 

 from the ratio of the volatile and soluble acids to the volatile acids a 

 third column is di'awn. which may be used to determine the nature of 

 I'ats containing large amounts of volatile acids. 



Theine in tea, J. Kochs {Re>\ Cxdt. Colonlales, 7 {1000), No. 60, 

 p. J(9J^; abs. in Jour. Sac. Cheut. Incl., W {1001), No. 1, j>. J<y).— The 

 percentage of theine in the teas examined was as follows: Souchong, 

 2. S3; Flower Pekoe, 4.36; Scented tea, 3.08; Pouchong, 3.41; Congou. 

 3.83; Oolong. 3. ()6; Cha Morumby, a Brazilian tea, 3.11. The (juality 

 and value of tea does not depend alone upon the composition, tnit also 

 u})on the u})pearance, aroma, and taste of both the leaf and the 

 infusion. 



