CHEMICAL SCIENCE. 219 



disk, and it is around the margin of this disk that the color is first dis- 

 coverable. By gently agitating the mixture, the whole will change 

 from a pink to the red color of carmine. White saucers are the best 

 vessels for testing it in ; and the quantity of the material to be used 

 is an ounce of the oil to about a drachm of the acid. 



NEW TEST FOR THE NITRATES. 



THE following new test for the nitrates has been discovered by Mr. 

 Schseffer : Add to the solution supposed to contain nitrates one or 

 two drops of yellow prussiate of potash. These should not be enough 

 to give a perceptible tinge to the liquid. A few drops of acetic acid 

 are then to be added, and immediately, or in a few minutes, accord- 

 ing to the quantity of nitrate present, the liquid assumes a rich yel- 

 low tint. Proceedings of the American Association. 



ON THE PURIFICATION OF OIL OF VITRIOL FROM NITRIC ACID. 



MR. ALEXANDER KEMP, of Edinburgh, has discovered a method of 

 purifying oil of vitriol from nitric acid, which renders it unfit for 

 many of its applications. He says, " If oil of vitriol be diluted to the 

 specific gravity of 1.715, or thereabouts, and a stream of sulphurous 

 acid be passed through it, the whole of the nitric, nitrous, or hyper- 

 nitrous acid will be reduced to binoxide of nitrogen, which, along 

 with the excess of sulphurous acid, may be totally removed by boil- 

 ing." Instead of sulphurous acid gas, a saturated solution of sul- 

 phurous acid may be used. Jamesoji's Journal, April. 



TEST FOR QUININE. 



M. VOGEL, JR., has discovered a new test for quinine. To a solu- 

 tion of quinine in alcohol or water, some drops of chlorine-water are 

 first added, and then a concentrated solution of ferrocyanide of potas- 

 sium, when the liquid assumes a beautiful bright-red color. If the 

 solution of the ferrocyanide has not been sufficiently concentrated, the 

 same effect is produced by adding some drops of ammonia. For the 

 examination of quinine in a dry state, a small quantity of the body is 

 placed in a watch-glass, and, while it is stirred with a glass rod, a 

 few drops of chlorine-water are first added, and then the ferrocyanide. 

 A beautiful red is produced, soon changing to green. Bulletin de 

 Therapeutique, Vol. XXXIX. 



CAIL-CEDRA, A SUBSTITUTE FOR QUININE. 



AFTER the discovery of sulphate of quinine, endeavours were made 

 to find an analogous medicine capable of supplying the place of this 

 valuable substance ; but all these were fruitless, and sulphate of qui- 

 nine is still the febrifuge par excellence. But good quinquinas are be- 

 coming scarce, and very *ear ; the working of them, for many years 

 in their native forests, has been an actual devastation, and it is to b' 



