CYANOGEN. 417 



COMPOUND OF NITROGEN AND CARBON. 



This compound is named here, because, in the strictness of logi- 

 cal arrangement, this is the place for its introduction ; but its fuller 

 developement, and that of the connected topics, will be reserved to 

 a more advanced stage of this work, because the subject is compli- 

 cated and difficult, and requires the previous knowledge of the most 

 important facts of elementary chemistry. These topics will be 

 touched upon again under iron, and the other metals, and finished 

 under the chemistry of animal bodies, from which the principal 

 agents of this family are derived. 



CYANOGEN. 



1. NAME. xuavo^, blue.* 



2. PROCESS. If prussian blue, 8 parts, be boiled with red oxide 

 of mercury, 1 1 parts, a crystallizable salt will be obtained, the prus- 

 siate or cyanuret of mercury, by heating which, in a dry state, in a 

 retort, we obtain over mercury a gas called cyanogen, which burns 

 with a superb purple and violet flame. It is composed of 2 equiva- 

 lents of carbon, and 1 of nitrogen. 



PRUSSIC ACID, OR HYDRO-CYANIC ACID. 



1. NAME. Called prussic acid, from prussian blue, the parent 

 substance, from which, as above, the cyanuret or prussiate of mercury 

 is obtained, which affords this agent. The term, hydro-cyanic, refers 

 to the union of hydrogen with cyanogen, to form this acid. 



2. PROCESS. Decompose the prussiate, or cyanuret of mercury, 

 in a retort by muriatic acid, and condense the volatile product in an 

 ice cold receiver. 



3. PROPERTIES. It is the most diffusive and virulent poison 

 known ; it kills small animals when a drop is applied to the tongue, 

 and a few drops are more than sufficient to extinguish life in a vigor- 

 ous man. It exists ready formed in the vegetable kingdom, in 

 peach blossoms, and peach kernels, in the bitter almond, in the lauro 

 cerasus, &ic. It, or its radical, combines with alkaline and earthy 

 bases, and the prussiates or cyanurets of these bodies furnish us with 

 tests that are highly useful in detecting the metals. The prussic prin- 

 ciple is transferred to them, front prussian blue, and these applications 

 may be occasionally mentioned before the subject is fully exhibited. 



There are two acids composed of cyanogen and oxygen, call- 

 ed, the one cyanic, and the other fulminic acid ; and one of them is 

 supposed to exist inthe fulminating silver, and in fulminating mercury. 



In allusion to Prussian blue. 

 53 



