280 Chronicles of Science. [April, 



arrived at with the induction spark. Carbonic acid is completely de- 

 composed by the induction spark when a piece of phosphorus is 

 placed on the surface of the mercury in the eudiometer tube to absorb 

 the oxygen set free. After passing the sparks for twenty-four hours, 

 only an equal volume of carbonic oxide was left. 



Deville also points out that although a volume of ammonia is 

 doubled by the action of the sparks, the decomposition is never com- 

 plete. Notwithstanding that no absorption is shown when water is 

 introduced into the eudiometer, a few bubbles of hydrocloric acid 

 passed in, determine the deposition of chloride of ammonium, and the 

 mercury instantly rises. 



Messrs. Buckton and Odling have made an important discovery in 

 some organo-compounds of aluminium.* They have formed alumi- 

 nium ethide and methide. Apart from the importance of these 

 compounds in determining the atomic weight of aluminium, they pos- 

 sess great interest in themselves. They are both colourless, mobile 

 liquids, which take fire spontaneously in the air, burning with a smoky 

 flame, which, along with the carbon, produces abundant flocculi of 

 alumina. In water the ethide decomposes with explosive violence. 

 The determinations of the vapour densities of these bodies have led 

 the authors to the adoption of the formulae Al Et 3 and Al Me 3 , which 

 agrees with the high atomic weight required by the specific heat of 

 aluminium. It must be added that the vapour density of aluminium 

 methide, like that of aluminic chloride, appears to be anomalous. 



Professor Williamson, in a communication to the Eoyal Society, f 

 has since shown strong reasons for still adhering to the low atomic 

 weight of aluminium. 



In connection with organic chemistry, we may mention that Dr. 

 Hofmann has contributed J further researches on the colouring-matters 

 derived from coal-tar, which we must now cease to speak of as aniline 

 colours since the author and Mr. Nicholson have shown that toluidine 

 is an essential constituent. These researches, while conclusive 

 against the views of M. Schiff, still leave the exact constitution of the 

 colours a matter of conjecture. 



In advanced organic chemistry we need hardly say that incessant 

 and rapid progress continues to be made, the discovery of new bodies 

 almost exceeding the ingenuity of the discoverers to find names for 

 them. From these discoveries we gain daily a clearer insight into the 

 constitution of chemical compounds ; but at present it is impossible 

 to convey to general readers an idea of the facts revealed. 



Plants containing theine have been so universally adopted as articles 

 of diet, that man would seem to have been guided to their use by a 

 sort of instinct. Physiologists may dispute about the use and the evils 

 or benefits which result from it, but it is a fact that everywhere man, 

 civilized and uncivilized, seems to exhibit a craving for substances that 

 contain it. The medicinal effects of pure theine have as yet been but 

 imperfectly ascertained, and we may regard it as fortunate that a new 



* ' Transactions of Eoyal Society,' v. xiv. p. 19. 

 t 'Transactions of Eoyal Society,' xiv. p. 74. 

 t ' Transactions of Eoyal Society,' v. xiii. p. 485. 



