219 



Dr. Hare communicated to the Society, a summary of his 

 objections to the arguments in favour of the existence, in the 

 amphide salts, of compound radicals analogous to cyanogen. 



Dr. Hare stated, that the success which had been conceived to at- 

 tend the inferences lately made, respecting the existence of compound 

 radicals in various interesting organic substances, had led some dis- 

 tinguished chemists to suppose that the salts heretofore believed to 

 consist of acids and bases, might consist of a compound halogen body 

 or " salt radical," with a metal or with hydrogen. 



Having given to the facts and arguments advanced in favour of 

 this new doctrine the most sedulous consideration, Dr. Hare declared 

 himself to have arrived at the conviction that it was susceptible of 

 being refuted. 



Accordingly, he had prepared an essay which it was hoped would 

 be found to justify the view of the question which he had taken. He 

 did not, however, deem it proper to take up the time of the Society 

 by entering into the subject fully in a verbal communication; he 

 would only submit a summary of the opinions which he hoped to 

 justify in the essay which he intended to publish. 



(a) The community of effect, as respects the extrication of hydro- 

 gen by contact of certain metals with aqueous solutions of sulphuric 

 and chlorohydric acid, is not an adequate ground for an inferred ana- 

 logy of composition; since it must inevitably arise that any radical 

 will, from any compound, displace any other radical, when the forces 

 favouring its substitution preponderate over the quiescent affinities : — 



(&) But if, nevertheless, it be held that the evolution of hydrogen 

 from any combination, by contact with a metal, is a sufficient proof 

 of the existence of a halogen* body, simple or compound, in the com- 

 bination, the evolution of hydrogen from water, by the contact with 

 any metal of the alkalies, must prove oxygen to be a halogen body; 

 also the evolution of hydrogen from sulphydric, selenhydric, or tellu- 

 hydric acids, by similar means, would justify an inference that sul- 

 phur, selenium and tellurium, as well as oxygen, belong to the halo- 

 gen or salt radical class : — 



(c) The amphigen bodies being thus proved to belong to the halo- 

 gen class, oxides, sulphides, selenides, and tellurides, would be haloid 

 salts, and their compounds double salts, instead of consisting of a 

 compound radical and a metal : — 



* The epithet halogen is applied to bodies whose binary compounds with 

 metals are deemed salts, and which are consequently called haloid salts. 



