contained in Coal-gas Naphtha. 197 



I have already alluded to the determination of platinum. 

 This analysis leads to the formula adopted at the determina- 

 tion of the atomic weight, CI H, C 12 H 7 N + Cl 2 Pt, which is spe- 

 cified in the following calculated per cents.: — 



1 2 atoms Carbon . . 91025 



8 ... Hydrogen . 99'83 



1 ... Nitrogen . 177*04 



3 ... Chlorine . 1327*95 



1 ... Platinum . 1233*50 



3748*57 



Chloride of Mercury and Ci/anol. — I have already adverted 

 to the white precipitate produced by cyanol in chloride of 

 mercury. If in this experiment cyanol alone or a watery so- 

 lution of it be employed, the double compound ascends to the 

 surface of the liquid in the form of a pasty mass. When cor- 

 rosive sublimate is mixed with an alcoholic solution of cyanol, 

 a silky white powder is formed, which, after some time, be- 

 comes crystalline. By washing with water, in which it is only 

 slightly soluble, the crystals are obtained pure. This salt does 

 not change its colour at 212°, but cyanol is slowly separated, 

 for which reason I analysed the compound dried at the ordi- 

 nary temperature of the air. 



The carbon and chlorine were determined in the usual way. 

 I endeavoured to combine the determination of the mercury 

 with the chlorine, by forming a bulb of about three inches in 

 length in the foremost part of the combustion tube, in order 

 to receive the mercury. In this procedure, however, it is very 

 difficult to separate the mercury from the undecomposed 

 cyanol, which distils over during the operation. The analysis 

 succeeds, however, very well when the salt is ignited with 

 chromate of lead, if the forepart of the tube is cut off with a 

 file after all the mercury has collected in the appropriated 

 bulb, and the water, which has passed over, removed by suck- 

 ing a stream of cold air through the apparatus. The forma- 

 tion of a small quantity of hyponitrite of mercury causes some- 

 times a slight excess in the result. 



I obtained in my analysis the following numbers : — 



0*7153 grm. of chloride of mercury and cyanol gave 0'3693 

 grm. of carbonic acid ; 2*6675 grm. of chloride of mercury 

 and cyanol gave 2*2005 grm. of chloride of silver; and 1*1603 

 grm. of chloride of mercury and cyanol gave 0'7035 grm. of 

 mercury. 



From the above is deduced the formula C l2 H 7 N + 3(C1 Hg), 

 which I annex in per cents. 



