380 Transactlom. — Chemistri/. 



2nd. That it also combines with hydrogen and forms with it a compound 

 analogous to hydrochloric acid. 



3rd. That when passed into a solution of any caustic alkali it is in part 

 oxidized, alkaline cyanates and cyanides forming. 



4th. That when cyanides are electrolyzed the radical is evolved at tbe 

 positive pole. 



If to this we add that cyanide of potassium crystallizes in cubes, as do the 

 chlorides, bromides, and iodides of this base, I think we exhaust the evidence 

 which can as yet be alleged in favour of the analogy of cyanogen to the 

 elements referred to. 



Such are the reasons for classifying cyanogen with these radicals, and I will 

 now go over them seriatim. 



In the first place it is true that cyanogen combines directly with the least 

 oxidizable metals, but so does oxygen when in the allotropic state, also sulphur 

 at a slight elevation of temperature, and further its hydride (sulphuretted 

 hydrogen) imitates hydrocyanic acid in presence of the metals instanced ; 

 oxygen and sulphur should therefore on this principle be admitted along with 

 cyanogen into the group of radicals, which would be absurd, as they are not 

 admitted as radicals at all. Therefore these tests are unreliable. 



In the second place, besides cyanogen, sulphur and a number of other 

 elements combine readily with hydrogen, the bulk of which are not halogens, 

 while in reference to the supposed analogy existing between hydrocyanic and 

 hydrochloric acids, I really fail to see any grounds for this. 



Hydrochloric acid is a very strong one, intensely acid, and forms salts with 

 the alkaline metals which are quite neutral. Hydrocyanic acid on the other 

 hand, if acid at all (which I doubt), is so feebly so that " it scarcely affects the 

 blue litmus paper"; indeed I believe it to be neutral, as any minute acid 

 reaction which has been obtained in respect to it may be due to carbonic acid, 

 hydrocyanic acid being very prone to decompose with evolution of carbonic 

 acid. 



Further, in accord with this, the salts of cyanogen with the alkaline metals 

 are not neutral, as are the corresponding salts of the chlorine group, but 

 strongly alkaline. 



In reference now to the third sup))oscd joint characteristic of cyanogen 

 and the radicals to which it is compared, we can parallel this in the case of 

 sulphur and phosphorus ; thus cither of these elements, when warmed with a 

 solution of any caustic alkali, forms oxygenated and haloidal salts, a part of 

 them being oxidized at the exj)ense of the oxygen of the alkali, as in the case 

 of cyanogen, chlorine, etc., under these circumstances. 



Lastly, as to the polar affinities of cyanogen and the crystalline form of its 

 potassium salt. Sulphur and oxygen when liberated by voltaic action also 



