€0 Royal Society .- — 



as may be seen by the following comparison : — 



Theory. Experiment. 



57 Carbon x 6 = 342 = 34-097 33-947 



44 Hydrogen x 1 = 44 = 4-386 4-423 



2 Nitrogen x 14 = 28 = 2-791 2-700 

 16 Oxygen X 8 = 128 = 12-764 12-800 



3 Iodine X 127 = 381 = 37-986 37-914 

 2SuIph.acidx 40 = 80 = 7-976 8-216 



1003 100-000 100-000 



giving— 



Carbonic acid 125-22 124-472 per cent. 



Water 39-474 39-807 „ 



Consequently the silky salt will be the optical salt + 4 atoms of 

 water, which, under the influence of excess of sulphuric acid and 

 prolonged delay at 62° Fahr., are assimilated by that salt ; and 

 which additional water, on boiling in spii-it, is lost, and the optical 

 salt recrystallized on cooling. 



If the temperature be not too high at first, the silky crystals 

 may be produced without the appearance of the optical. And the 

 silky crystals at 212°, or at 62° Fahr. over sulphuric acid, become the 

 dry residue or tri-hydrate, which, when boiled in spirit, becomes the 

 optical, by assimilating 2 atoms of water, as may be seen by com- 

 paring the three proposed formulae : — 



a. Optical. 



p|2SO'HO + 5HO=967 



^. Silky Salt. 

 ^ j3l2SO^HO + 9HO=1003. 



y. Dry Residue. 

 C"H^N=0'| 2SO^HO + 3HO=949. 



The results of the analysis of the cinchonidine salt having been so 

 remarkably different from those of the formulae generally adopted for 

 the pure alkaloid, the author was induced to prepare some perfectly 

 pure quinine, taking especial pains to exclude all cinchonidine ; and 

 having from that prepared some iodo-sulphate of quinine, to submit 

 it to equally rigid analysis. 



The results are the following : — 



These optical crystals lose 2 -4 9 per cent, water by prolonged 

 drying at 212° in Liebig's drying apparatus. 



