DR SAMUEL BROWN ON PARACYANOGEN. 



took place, and the odour of cyanogen was evident. Cyanogen having been dif- 

 fused away, and replaced by air, the two pieces, with their contents, weighed 

 390.5 grs., 1.7 gr. having been lost by explosion and diffusion ; mercury was sub- 

 limed away from both, and they weighed 383.1 grs., giving 7.4 grs. for mercury. 

 Paracyanogen was now removed, and the tubes cleaned with oxide of copper, when 

 they weighed 381.7 grs., giving 1.4 gr. for paracyanogen. These three weights of 

 cyanogen, mercury, and paracyanogen, make up 10.55 grs., less by only 0.05 gr. 

 than that of the original compound ; and the first (1.7 gr.) may be so divided be- 

 tween cyanogen and mercury as exactly to complete their ratios. In this expe- 

 riment, 1.4 gr. of cyanogen was changed into its solid form. 



6. 16.25 grs. of the salt were put into a green glass-tube, three inches long, and 

 weighing 116.55 grs., the gross being 132.8 grs. The mouth of the tube was 

 plugged half an inch down with stucco-paste ; the whole was imbedded in a stucco- 

 mould, and immersed in a sand-bath, which was kept near the low red heat for 

 more than an hour. Freed from the mould and carefully cleaned, it was exa- 

 mined : 0.9 gr. of mercury was procured from the plug ; 13.1 grs. of brown pro- 

 duct mixed with mercury taken from the tube, and 0.4 gr. of incrusted paracya- 

 nogen removed by oxide of copper, so that there had taken place a loss of 1.85 gr. ; 

 and this experiment shews that, even under the pressure of a stucco-plug, more 

 than half an equivalent of cyanogen is given off in the form of paracyanogen. 

 This modification was tried thrice with analogous results ; at least half of the 

 cyanogen having been transformed in every case. 



7. 50 grs. were closely packed in a small iron bottle fitted with a screw-stopper, 

 which, though tight, had been observed, in a previous experiment, to admit of the 

 passage of mercurial vapour under high pressure. Having been weighed, it was 

 enclosed in a shut crucible, and kept more than an hour at a low red heat, after 

 which it was found that the screw had allowed the expected exit, and that the 

 total loss was only 1.0 gr. greater than the weight of the mercury. The fixed 

 residue was good paracyanogen, containing no traces of either mercury or unde- 

 composed salt, but having lost some of its nitrogen. The loss of nitrogen was dis- 

 covered by the action of concentrated sulphuric acid. When it is taken into con- 

 sideration that the 1 gr. of total loss must be at least partly attributed to the ex- 

 trication of nitrogen from produced paracyanogen, the transformation effected by 

 this experiment appears to be very complete. 



8. 32.15 grs. were crushed into a strong test-tube, which was sealed close 

 to the surface of the cyanuret, and immersed three hours in a boiling linseed- 

 oil bath. It seemed from without to be thoroughly decomposed, the charac- 

 teristic brown powder, with globules of mercury interspersed, having replaced 

 the white needles. Having been first weighed, it was filed across over a sheet 

 of paper ; a trifling explosion took place ; the scattered product and the pieces 

 of the tube, weighed together, indicated a loss by explosion of 0.5 gr. Thus 

 the pressure of contained air and 0.5 gr. of cyanogen, at the boiling heat of 



