the Action of Water on White Precipitate, fyc. 433 



There are here equally produced by the two atoms of white 

 powder and two of water, two of sal-ammoniac, and one of the 

 yellow powder, of which the composition should be 

 Mercury 85*72^ 



C hlo ' ine TtlUoO'OO 



Amidogene 3*42 I 



Oxygen 3'38J 



and it should yield in analysis 3*63 per cent, of ammonia. 



The definite composition of this yellow powder is thus evi- 

 dent, and the decomposition by which it is formed perfectly 

 explained. We see that all the results tend to show that in 

 these bodies the ammonia is not united with oxide of mercury, 

 but rather the metal with amidogene. The perfect demon- 

 stration of this principle, however, must be sought for in the 

 other metals. 



Of the Products of the Action of Alkalies in Excess on 

 White Precipitate. 



Grouvelle and other chemists have stated that by the action 

 of an excess of alkali on a sublimate solution, there is pro- 

 duced the ammoniuret of mercury which was discovered by 

 Fourcroy and examined by Guibourt, and to which I shall 

 hereafter speedily recur ; and even Dumas states, that " the 

 same compound (the ammoniuret) is obtained by pouring 

 ammonia into a solution of corrosive sublimate, and then 

 adding caustic potash in excess." My anxiety to obtain pure 

 ammoniuret of mercury, joined to the interest of the prece- 

 ding investigations, led me to examine the nature of the pro- 

 ducts thus obtained ; and the results, as correcting an error 

 very generally fallen into, are worthy of being described. 



When corrosive sublimate is decomposed by ammonia, the 

 quantity of alkali in excess does not appear to interfere much 

 with the reaction before described. If the liquors be cold, 

 there is obtained white precipitate ; and if it be boiled, the 

 heavy yellowish powder is produced; the liquor retaining 

 in the former, one-half, in the latter, three-fourths of the 

 chlorine of the sublimate. Again, if white precipitate be 

 boiled in water, rendered strongly alkaline by ammonia, we 

 obtain the yellowish powder, and half the chlorine and half 

 the ammonia of the precipitate are disengaged. Thus, water 

 of ammonia acts on white precipitate only as water itself does, 

 the nature of the reaction being the same in both instances. 

 Again, when white precipitate was treated with potash for 

 analysis, as in L. and E. Phil. Mag., vol. viii. p. 498, it has 

 been seen that the ammonia disengaged was but one-half what 

 it contained, the formation of the yellowish powder being the 



Third Series. Vol.11. No. 69. Nov, 1837. 3 K 



