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Dr. Hofmann's Contributions towards [June 16, 



boiled for hours with a lead salt and an alkali without the formation of 

 lead sulphide ; also, after treating with moderately concentrated nitric 

 acid, the sulphur contained in the body remains unchanged. Only after 

 several days' boiling with alcoholic soda, the sulphur separates as sodium 

 sulphide, and as it appears sodium hyposulphite. The determination of 

 the sulphur, however, offers no difficulty when the vapour of the com- 

 pound is passed over a red-hot mixture of nitre and sodium carbonate. 

 The careful analysis of the new crystals leads to the formula 



C U H 10 N 2 S. 



They are consequently derived from two molecules of thiobenzamide from 

 which one atom of sulphur and four atoms of hydrogen have been removed, 

 the latter in the form of hydriodic acid, 



2C 7 H 7 NS + 211 = C 14 H 10 N 2 S + 4HI + S. 

 Chlorine, bromine, and moderately diluted nitric acid act upon thiobenza- 

 mide in the same way as iodine. These reagents, however, are not to be 

 recommended for the preparation of the new compound, as the action 

 easily goes too far, causing the formation of chlorinated, brominated, and 

 nitro-products, which contaminate the normal compound. In fact, Mr. 

 Richard Dunklenberg, whilst studying thiobenzamide last summer in the 

 Berlin Laboratory, has had already in his hands the new sulphuretted 

 compound ; but as he employed bromine for its preparation, the substance 

 was obtained in a less pure state, and consequently he did not succeed 

 in interpreting the reaction. 



With regard to the constitution of the new body, it may be considered 

 as consisting of two molecules of benzonitrile, which are held together 

 directly by the sulphur. Different views may be taken of the arrange- 

 ment of the atoms in the molecule. Probably the carbon atoms outside 

 the phenyl group are joined together by the sulphur ; and there is 

 then also connexion between the nitrogen atoms. This latter supposition 

 is strengthened by the behaviour of the crystals with nascent hydrogen, 

 described below. But I will not go further into this question at present, 

 since the prosecution of the new reaction in other series promises to yield 

 further experimental data for a profitable discussion of the subject. For 

 the same reason, I refrain at present from proposing a name for the new 

 sulphur-compound. 



The stability of this substance is remarkable. It can be heated for a 

 long time to 150° in sealed tubes with hydrochloric acid, dilute sul- 

 phuric acid, and even moderately strong nitric acid, without undergoing 

 decomposition. It dissolves in concentrated sulphuric acid by the aid of 

 a gentle heat, and the addition of water precipitates it again unchanged. 

 The compound is decomposed rather more readily by alkalies, although, 

 as already mentioned, it is necessary, even in this case, to boil for days. 

 In this case benzoic acid is reproduced with slow evolution of ammonia. 

 Evidently the sulphur here first separates from the molecule, and is dis- 



