330 Dr. Clarke on Cyanide of Potassium^ as produced 



coal for fuel were employed ; but owing to the rare use of coke 

 in Scotland now, I am, as yet, not aware whether the same 

 product has been observed where coke is the fuel con- 

 sumed. 



The principal ingredient in the salt thus obtained, is cyanide 

 of j)otassium. In a quantity that was, about a year ago, sub- 

 mitted to an examination whereof the sequel will give an 

 account, the cyanide of potassium made up about 53 parts in 

 the 100, the rest being carbonate of potash, intermixed with 

 a small quantity of carbonate of soda; but another quantity 

 that was examined about a year previously,contained more than 

 two thirds of cyanide of potassium. One learns, not without 

 surprise, that so remarkable a product should occur from such 

 materials, and under such circumstances. That potassium 

 should be there, from what source as yet I know not, will in- 

 dicate that the presence of that element, in even unpromising 

 materials of soils for vegetation, is more general than is usually 

 suspected. Nor will the iron-master fail, from this intimation, 

 to warn all under his charge whom it may concern, of the 

 perilously poisonous character of this product — a warning not 

 idle, I presume, since on a visit to the Clyde iron-works I 

 learned that the workmen, having discovered its alkaline pro- 

 perties, some of their wives, " on household thoughts intent," 

 had resolved to make the cyanide of potassium available in their 

 washing-tubs. The product will, however, better merit the 

 attention of the pharmacian, as affording a copious and cheap 

 source whence to obtain cyanide of potassium. 



The details of the investigation, having no novelty of me- 

 thod to boast of, might not be worth giving, were there not 

 strong reasons for believing that, for want of due precautions, 

 a similar product has been more than once — in the hands too 

 of able chemists, mistaken for carbonate of potash. This in- 

 duces me to give the details, 



A portion of the salt, selected as free from insoluble admix- 

 ture, was dissolved in water, which was done easily, and to the 

 solution, which was distinctly alkaline, dilute nitric acid was 

 added, until the solution, being gently heated, became neu- 

 tral. Effervescence took place. The evolved gases betrayed 

 the presence of carbonic acid by precipitating lime-water, 

 and of hydrocyanic acid by the smell of it, which prevailed. 

 The neutral solution gave no precipitate by nitrate of barytes, 

 or nitrate of silver, — indicating the absence not only of sul- 

 phates and chlorides, but that of salts of several other acids 

 such as these reagents would precipitate. The same solution 

 was unaffected by sulphuretted hydrogen, by sulphuret of 

 potassium, by yellow ferro-prussiate of potash, by oxalate 



