72 ANNUAL KECORD OF SCIENCE AND INDUSTRY. 

 CERIUM A TEST FOR STRYCHNINE. 



The oxide of cerium is recommended as a valuable test of 

 strychnine, since when concentrated sulphuric acid is poured 

 over strychnine, and oxide of cerium added to the mixture, a 

 beautiful blue color makes its appearance, a similar result 

 also taking place when the bichromate of potash is used in- 

 stead of cerium. The combination first mentioned, however, 

 with the same intensity of color, is much more durable, so 

 that when the chrome reaction has long since disappeared, 

 that produced by the cerium is persistent and easily recog- 

 nized. The blue tint passes gradually into a cherry-red, and 

 then remains unaltered for several days. It is stated that 

 the one hundred thousandth of a grain of strychnine can be 

 readily recognized by this test. Other vegetable alkaloids 

 give a totally different reaction with cerium, and can not, 

 therefore,be confounded with the strychnine. 15 (7,xvi.,256. 



TESTING THE PURITY OF HYDRATE OF CHLORAL. 



The purity of hydrate of chloral may, it is said, be tested 

 by means of a concentrated solution of potash. . The pure 

 hydrate does not color this at all, or at most only a feeble 

 yellow, and gives forth the pure smell of chloroform. Should 

 the liquid assume a brown color, and the smell of chloro- 

 acetic acid be combined with that of chloroform, or should 

 gases of a pungent odor be developed, which is not seldom 

 the case, the product is impure and unfit for use. 15 C, 

 1870,94. 



TEST FOR BENZOLE. 



For distinguishing genuine benzole, or that made of coal 

 tar, from that prepared from petroleum, Brandberg recom- 

 mends us to place a small piece of pitch in a testing tube, 

 and pour over it some of the substance to be examined. The 

 genuine will immediately dissolve the pitch to a tar-like 

 mass, while that derived from petroleum will scarcely l>e col- 

 ored. 12 (7, v., May, 1871, 39. 



DETECTION OF BUTYRIC ACID IN GLYCERINE. 



The presence of butyric acid in glycerine may be detected, 

 according toM.Perutz,by mixing the concentrated glycerine 



