296 Dr. R. H. Brett and Mr. J. D. Smith's Experiments 



grs. of pa racy nnogen j obtained by the spontaneous decomposi- 

 tion of prussic acid, were stuffed into a small crucible of Ber- 

 lin porcelain furnished with a cover; this covered crucible wns 

 completely imbedded in plaster of Paris made into a paste 

 with water, in a Hessian crucible; a cover was then placed 

 over the latter and luted with China clay. 



This apparatus was placed in a sand-bath to dry, and after- 

 wards submitted for three hours to a full red heat; when cold, 

 the smaller crucible was carefully opened; there was found a 

 perfectly black carbonaceous-looking residue, weighing 4 grs.; 

 this black residue was ignited in a platinum capsule over a 

 gas flame, and there remained a very inconsiderable light 

 and grayish-coloured ash, which, when boiled in aqua regia, 

 entirely dissolved. The ash in question consisted of sulphate 

 of lime and traces of oxide of iron. — (R. H. B.) 



Again, 50 grs. of paracyanogen were placed in a porcelain 

 crucible under precisely similar circumstances to the last ex- 

 periment. The crucibles in this case were exposed to a full 

 white heat for two hours. When the smaller crucible was 

 opened, a black residue, like that obtained in the former ex- 

 periment, was found; this residue, when burnt in a platinum 

 crucible with access of air, was consumed, with the exception 

 of a trifling ash entirely soluble in aqua regia, and consisting 

 of sulphate of lime and oxide of iron, as in the former expe- 

 riment.-.^. H. B.) 



Not content with the results of the two experiments just 

 detailed, 50 grs. of paracyanogen were again subjected to an 

 intense white heat in a furnace capable of fusing metallic iron 

 and manganese, having previously rammed it tightly into a 

 Berlin crucible, to which was adapted a suitable cover ; these 

 were luted together very carefully ; when the luting, which 

 then presented no cracks, was dry, this crucible was placed 

 in an earthen one, and the vacant space filled up with a 

 ferruginous sand ; this again was covered and securely luted ; 

 after ignition for two hours it was withdrawn, when the resi- 

 duum proved to be a perfectly black substance, exactly re- 

 sembling that mentioned in the former experiments, weighing 

 about 5 grs. The sand had agglomerated into a solid mass 

 resembling soft white sandstone, and owing to a portion of 

 this getting mixed with the black residue in the crucible, the 

 exact weight could not be ascertained. The interior glaze of 

 the crucible, to the level of the original bulk of the paracy- 

 anogen, had assumed a black colour with a shade of brown, 

 which apparently penetrated to the depth of the glaze, but no 

 further; on exposure to long-continued heat with free access 

 of air, this black lining underwent but a very slight, if any, 



