CHEMICAL SCIENCE. 243 



gives us the alkaloid in crystals. It is now the chemist's business to 

 determine its properties, to be able to prove its individuality. I have 

 applied the. principles which I have just expounded to the detection 

 of morphine, iodine, strychnine, brucine, veratrine, emetine, colchi- 

 cine, aconitine, atrophine, hyoscyamine ; and I have succeeded in 

 isolating, without the least difficulty, these different alkaloids, previ- 

 ously mixed with foreign matters. I have thus been able to extract 

 by this process, morphine from opium, strychnine and brucine from 

 nux vomica, veratrine from extract of veratrum, emetine from extract 

 of ipecacuanha, colchicine from tincture of colchicum, and the like. 

 Thus it is in all confidence that I submit this process to the considera- 

 tion of chemists who undertake medico-legal researches. 



ON THE DETERMINATION OF PHOSPHORIC ACID BY MOLYBDATE 



OF AMMONIA. 



SILLIMAN'S Journ 1 for May contains the following article by Mr. 

 W. J. Craw, of New Haven, on the determination of phosphoric 

 acid by niolybdate of ammonia : 



The determination of phosphoric acid has always been one of the 

 most important and most difficult problems of analytical chemistry. 

 The bases with which it is most frequently united, are iron, alumina, 

 the alkalies and alkaline earths. Several of these combinations are 

 decomposed with very great difficulty, the phosphate of alumina in 

 particular, resisting nearly every effort to reduce it to its component 

 parts. Although good methods have been proposed for the analysis 

 of many of the simple phosphates, that of j)hosphate of lime for 

 instance, yet it usually happens that several of these occurs together ; 

 and until very recently no process has been devised which could effect 

 the separation of phosphoric acid from all the bases previously men- 

 tioned, when in company. A great amount of labor has been spent 

 bv chemists, within the last few vears, in the effort to overcome this 



/ 



difficulty. Numerous ways have been tried with greater or less 

 success, but most of these contain inherent difficulties, which in many 

 cases prevent their applications. Even Rose's process by carbonate of 

 baryta, though a monument of profound knowledge and admirable 

 research, is yet too complicated to yield good results, except in the 

 hands of those who have practised it so often as to be perfectly famil- 

 iar with all the necessary precautions. The great desideratum of a 

 simple and accurate method for the determination of phosphoric 

 acid, with whatever substances it may be combined, has been supplied 

 by Sonncnschein. He states that the yellow precipitate produced by 

 molybdate of ammonia in the solution of a phosphate, contains phos- 

 phoric acid as an essential constituent, and not, as asserted by 

 Svanberg, and Strnve, an accidental admixture. From several 

 analyses of this compound he finds it to contain about three per cent, 

 of phosphoric acid. A number of trials were also made to find 

 whether by this means phosphoric acid could be separated and deter- 

 mined quantitatively which were completely successfull. For this pur- 



