122 



Mr. E. Scliimck on the Colouring and 



[Recess^ 



The substance combined with oxide of lead contained, in 100 parts, 



C 41-60 



H 5-55 



N 2-40 



O 50-45 



100-00 



Two of the preceding determinations, viz. Analysis II. Series D and 

 Analysis IV. Series F, led to nearly the same results, the composition of 

 the substance contained in the lead compound corresponding in all three 

 cases with the formula Cgg NOg^. 



Being curious to ascertain what had been taken up by the oxide of mer- 

 cury which was employed in the purification of the substance used in the 

 preparation of the last lead compound, it was, after being washed, sus- 

 pended in water and decomposed by a current of sulphuretted hydrogen. 

 The filtered liquid was evaporated to a syrup. This syrup, which was 

 very brown, was dissolved again in a very little water, and the solution was 

 mixed with a large quantity of alcohol, which produced a glutinous deposit. 

 The latter, after the liquid had been poured off, was dissolved in a little 

 water, and to the solution there was added acetate of lead, which gave a 

 dirty-yellow precipitate. The filtered liquid was mixed with a large 

 quantity of alcohol, and the resulting precipitate was filtered off, washed, 

 dried, and analyzed. 



0-7170 grm. of this precipitate gave 0*5365 grm. carbonic acid and 

 0*1650 grm. water. 



1*0915 grm. gave 0*6240 grm. chloride of platinum and ammonium. 

 0-3615 grm. gave 0*2595 grm. sulphate of lead. 

 In 1 00 parts it contained therefore 



C..., 20*40 



H 2-55 



N 3*59 



20*65 



PbO 52*81 



100-00 



The substance combined with oxide of lead contained, in 100 parts, 



C 43-24 



H 5-41 



N.. 7*60 



O 43*75 



100-00 



From the unusually large amount of nitrogen yielded by this analysis, 

 it must be concluded that the oxide of mercury took up some substance 

 differing in composition from the extractive matters, probably a product 

 of decomposition of the latter. 



This series of experiments confirms in a remarkable manner the results 



