376 Mr. Phillips's Analysis of Tartarized Antimony. [May, 



Tartrate of potassa = 115 



Tartaric acid = 67 



Protoxide of antimony (53 x 2) = 106 



288" 



This, however, is an incorrect view of the subject, for it sup- 

 poses the salt to be anhydrous, which it is not, and the quantity 

 of oxide of antimony assigned is too small. Indeed having men- 

 tioned the results of xny experiments to Mr. Brande, he has 

 stated the composition differently in the table of equivalents, 

 adding in a note, " According to Mr. R. Phillips : in the text at 

 p. 254, the quantity of protoxide is underrated by one propor- 

 tional." Still, however, the statement is incorrect, as I shall 

 presently show. 



The quotation just made from Mr. Brande's Manual of Che- 

 mistry contains the opinion of the atomic constitution of tartar- 

 ized antimony expressed by Dr. Thomson in his System. In his 

 new work, already alluded to. Dr. T. observes (vol, ii. p. 440), 

 " No accurate analysis of this useful salt having been hitherto 

 made, I took the following method of ascertaining its consti- 

 tuents : 50 grains of picked crystals of tartar emetic were dis- 

 solved in distilled wat; r, and a current of sulphuretted hydrogen 

 gas passed through the liquid as long as any precipitate fell. 

 The bydrosulphuret of antimony thus obtained, when dried in 

 the open air, weighed 42-21 grains ; but when heated in a glass 

 tube, water was driven off, and a black matter remained, which 

 weighed 24"59 grains, and which was sulphuret of antimony, 

 equivalent to 18-032 grains of antimony, or 21"31 grains of pro- 

 toxide of antimony. 



"The liquid thus freed from antimony was evaporated cautiously, 

 and a quantity of bitartrate of potash obtained, which weighed 

 28'69 grains. But the integrant particle of bitartrate of potash 

 weighs 24-75; and 28-60 :^24-75 :: 21-31 : 18-384= the pro- 

 toxide of antimony united to an integrant particle of bitartrate 

 of potash. Now the protoxide of antimony weighs 6-5, and 

 65 X 3 = 19-5; this is a little more than I actually found, 

 because part of the sulphuret in my experiment adhered to the 

 glass tube, and could not be collected without loss. From this 

 experiment, which I thrice repeated, 1 have no doubt but the 

 constituents of tartar emetic are, 



2 atoms tartaric acid IQ'b 



3 atoms protoxide of antimony 19-5 



1 atom potash 6-0 



2 atoms water 2-25 



44-25" 



I shall now proceed to state the results of my analysis, 

 having already quoted from Mr. Brande, that I had obtained, 



