1862.] 127 



crystalline compound. The latter is also formed when boric methide 

 is passed into solution of ammonia. The colourless liquid stratum 

 which forms upon the surface soon solidifies when it is placed over 

 sulphuric acid in vacua. A quantity of the compound obtained by 

 this latter process was purified by solution in ether and subsequent 

 recrystallization : on being submitted to analysis, it yielded numbers 

 corresponding to the formula 



NH 3 + B(C 2 H 3 ) 3 . 



Ammonia boric methide is deposited from its ethereal solution in 

 magnificent arborescent crystals, which rapidly volatilize without re- 

 sidue when exposed to the air. They possess a caustic and bitter 

 taste and a very peculiar odour, in which both the smell of ammonia 

 and that of boric methide can be recognized. Ammonia boric me- 

 thide fuses at 56 Cent., and boils at about 1 10 Cent. In a current 

 of air, or better of carbonic acid, it sublimes at a very gentle heat 

 and condenses in arborescent crystals. Several determinations of 

 the specific gravity of the vapour of ammonia boric methide gave 

 the mean number 1*253, which indicates that the vapour of 

 ammonia boric methide consists of equal volumes of boric methide 

 and ammonia united without condensation. Thus the formula of 

 ammonia boric methide is a four-volume formula* a state of con- 

 densation which is usually considered to be abnormal, and which, 

 where it occurs, is generally explained by the assumption of a de- 

 composition of the body at the moment of conversion into vapour. 

 The proof of the disunion or integrity of the vaporous molecule of 

 ammonia boric methide would be interesting in connexion with these 

 so-called anomalous vapour-densities, but the author regrets his in- 

 ability to offer any sufficiently decisive solution of this problem ; for 

 although fused chloride of copper absorbs ammonia from the vapour, 

 yet it does so under circumstances which admit of the assumption 

 that the vapour of ammonia boric methide is decomposed by the 

 chloride of copper. 



Ammonia boric methide scarcely absorbs a perceptible amount of 

 oxygen at ordinary temperatures, even after several days' exposure to 

 the gas; but it takes fire below 100 Cent, when heated in contact 

 with the air. Its vapour is also very inflammable ; thus when am- 

 monia boric methide is placed under the receiver of an air-pump, and 



