124 [May 22, 



Another, but far less probable, view of the reaction presents itself 

 in the supposition that the three atoms of ethyl in boric ethide were 

 already present in the boracic ether, the action of the zincethyl being 

 simply to remove the whole of the oxygen from the boracic ether. 

 Kekule has, in fact, unreservedly adopted this latter view of the re- 

 action. 



So long as the organic radical of the zinc compound and that of 

 the boracic ether are identical, it is impossible to prove whether the 

 three individual atoms of ethyl in boric ethide were originally present 

 in the boracic ether, or have been derived from the zincethyl. In- 

 dicating by an asterisk the atoms of ethyl which finally become 

 part of the boric ethide, it is impossible to prove conclusively whether 

 the reaction takes place according to the first or second of the fol- 

 lowing equations : 



f C 4 H g O 2 f P TT * f Ql Hg* p TT 1 



(1) 2B J C 4 H 5 2 + 3Zn 2 ] |V=2B 4 C 4 H 5 * + 6 C ^ O 2 . 



[C 4 H S 2 I *"' (C 4 H 5 * 



fC 4 H 5 *0 2 fC 4 H s * p , 



(2) 2B \ C 4 H 5 *0 2 + 3Zn 2 j g=2B \ C 4 H 5 * + 6 C ^ O 2 . 



(C 4 H 5 *0 2 **** IC 4 H 5 * 



Although we cannot thus label, as it were, the atoms taking 

 part in the reaction, we can unerringly trace the movements of the 

 alcohol radicals, if we secure their identification by varying their 

 composition in the two compounds used in the reaction. The study 

 of the action of zincmethyl upon boracic ether would obviously thus 

 decide between these views. If boric ethide were produced from 

 these materials, Kekule' s hypothesis would be established ; but if, 

 on the other hand, boric methide were the result of the reaction, 

 then the correctness of the view originally taken by Mr. Duppa and 

 the author would be proved to be correct. The following results 

 were obtained in pursuing this inquiry : 



Boric Methide. 



When a strong ethereal solution of zincmethyl is added to boracic 

 ether, an elevation of temperature to the extent of 8 or 10 Cent, is 

 observed, whilst at the same time a most intensely pungent odour is 

 developed ; this odour, although it resembles that of boric ethide, is 

 far more powerful and more persistently irritating to the mucous 



