170 DR SAMUEL BROWN ON PARACYANOGEN. 



quickly raising the cyanuret to a full red ; mercury sublimed, some cyanogen was 

 observed to escape, and after the operation the apparatus was sealed down by the 

 blowpipe into small pieces, which, together, weighed 130.85 grs., indicating a loss 

 of 1.15 gr. ; whereas, if the products had been mercury and cyanogen, the loss 

 would have been 3.1 grs. The paracyanogen remaining in the tube weighed 2.3 grs., 

 and, with the exception of retained cyanogen, was pure. Thus, 2.3 grs. of the cyano- 

 gen of 14.9 grs. of cyanuret, appear to have been transformed into the solid isome- 

 ric ; but 2.3 grs. + 1.15 gr. is a slightly greater weight than that of all the cyanogen 

 contained in the weight of salt decomposed ; an error which is to be accounted for 

 by the hygrometric property of paracyanogen, and the small but appreciable loss 

 sustained by glass-tubes when much drawn out. 



16.4 grs. were treated exactly as in this experiment, the drawing having been 

 made more capillary ; and there was no loss, but the product contained slight traces 

 of undecomposed cyanuret, so that the value of the result was diminished. 



4. A quantity of cyanuret, weighing 10.81 grs., was put into a strong test- 

 tube, three inches long, which was then bent to an obtuse angle in the middle, 

 and six inches of thermometer tube, of so fine a bore that quicksilver neither rose 

 in it spontaneously, nor could be forced up by suction, was tightly sealed into the 

 open extremity. The containing part was held in a large spirit-flame, so as to 

 keep the rest of the apparatus out of the heated current ; and at the end of the 

 process there was found to be a loss of 1.5 gr. The mercury had sublimed past 

 the bend, at which the tube was then broken across. The upper part, with the 

 mercury, weighed 124.8 grs., and lost 7.8 grs. by the removal of its contents ; while 

 the lower, containing paracyanogen, weighed 43.4 grs., and, on being emptied and 

 cleaned out by means of black oxide of copper, lost 1.5 gr. Now, 2.2 grs. cya- 

 nogen of 10.81 grs. of bicyanuret of mercury ; so that all the cyanogen but 0.7 gr. 

 was, in this case, produced as paracyanogen. But 7.8 grs. of mercury implies a 

 loss of 0.8 gr., to be accounted for partly by experimental error, and partly by the 

 first loss of 1.5 gr. during the process; for 1.5 gr. first loss, + 1.5 gr. paracya- 

 nogen, -|- 7.8 grs. mercury, = 10.8, a weight short by only 0.01 gr. of that of the 

 salt submitted to decomposition. 



5. Eight inches of the strongest green glass-tube, one-third of an inch in dia- 

 meter, sealed at one end, and bent to an angle of about 130 between the third 

 and fourth inches from the bottom, having been tared, some well-dried crystals of 

 bicyanuret of mercury were introduced, and found to weigh 10.6 grs. The open 

 end was hermetically sealed. The containing limb of this little shut retort was 

 put into a jacket-tube, and surrounded by fine sand within the jacket. It was 

 suspended half an hour in a very large spirit-flame, at the end of which time com- 

 plete decomposition had been effected, except that a very small quantity had been 

 carried up with the mercurial vapour. After the reduction of the traces in the 

 bend, the apparatus was found to have gained 0.05 gr. from the sand, or otherwise. 

 It was filed across at the knee over a sheet of clean paper ; a slight explosion 



