72 



Dr. Hofmann on Homologues and Analogues [Recess, 



perties of which I have lately described to the Royal Society *, yields like- 

 wise a mustard-oil, if it be successively treated with bisulphide of carbon 

 and mercuric chloride. I have not, however, more minutely examined this 

 compound. 



All the mustard-oils here mentioned exhibit, more especially with refer- 

 ence to ammonia and its derivatives, the same reactive power which belongs 

 to ethylic mustard-oil, more minutely described in my former communica- 

 tion, and by which the mustard-oil par excellence, the well-known allyl- 

 compound, has long fixed the interest of chemists. Of the legion of urea- 

 like bodies which are here possible, I have prepared but few. It may be 

 stated that the sulphuretted methylic and amylic ureas, and also the sulphu- 

 retted methylamylic and amyltolylic ureas vie with each other as to beauty 

 and facility of crystallization. I have not, however, examined more minutely 

 these ammonia compounds, their study promising but very little scientific 

 gain. On the other hand, I have investigated with some care the metamor- 

 phoses of the mustard-oils, since their comparison with the corresponding 

 transformations of the sulphocyanic ethers promised to elucidate the dif- 

 ferent construction of the two groups of bodies. 



The results of these inquiries unequivocally confirm the view suggested 

 by the formation of the two classes of compounds. It is indeed only neces- 

 sary to trace their origin in order to understand the nature of this difference. 

 We could not select better illustrations than the isomeric terms of the 

 methyl-series. Both bodies, methylic mustard-oil and sulphocyanide of 

 methyl, are in the last instance derived from exactly the same compounds, 

 viz. methylic alcohol, bisulphide of carbon, and ammonia. Let the mole- 

 cules of these three compounds unite with separation of 1 molecule of water 

 and 1 molecule of sulphuretted hydrogen, and a body will be formed pos- 

 sessing the composition of both methylic mustard-oil and sulphocyanide of 

 methyl. 



CH 4 + CS 2 + H 3 N = H 2 + H 2 S + C 2 H 3 NS. 



Accordingly the nature of the body produced must depend upon the 

 conditions (it might be almost said upon the order) in which the molecules 

 of water and sulphuretted hydrogen are separated from the aggregate of 

 atoms. 



Conceived in its simplest form, the first step of the generation of methylic 

 mustard-oil consists in the action of ammonia upon methylic alcohol, when 

 methylamine is produced with separation of water. 



CH 4 0-fH 3 N=H 2 + CH 5 IS T . 



In a second phase of the process, methylamine is acted upon by bisul- 

 phide of carbon, the products being methylic mustard-oil and sulphuretted 

 hydrogen. 



C H. N + C S 2 = H 2 8 + C 2 H 3 N S. 



* Proceedings, vol. xvi. p. 445. 



