128 [May 22, 



the air is being withdrawn, the explosion of the mixture of air and 

 vapour in the cylinders of the pump is frequently determined by the 

 rise of temperature consequent upon the depression of the pistons 

 when the rarefaction has become considerable. 



Boric methide is also absorbed by aniline with great avidity. 

 Acids expel the gas from this compound unchanged. 



Terhydride of phosphorus has no action upon boric methide. A 

 mixture of equal volumes of the two gases is spontaneously inflam- 

 mable, burning with a yellowish- white flame, in which the charac- 

 teristic green tinge attending the combustion of boric methide is no 

 longer perceptible. 



Compounds of Boric Methide with Potash, Soda, Lime, and Baryta. 

 Solution of caustic potash absorbs boric methide with great energy. 

 The saturated solution, exposed over sulphuric acid in vacuo, dries 

 down to a gummy mass, which scarcely exhibits signs of crystalliza- 

 tion. The same body may be more conveniently formed by decom- 

 posing ammonia boric methide with alcoholic solution of potash, 

 taking care to employ an excess of the former. On evaporation over 

 sulphuric acid in vacuo, the excess of the ammonia compound vola- 

 tilizes and is decomposed by the sulphuric acid, with the elimination 

 of boric methide ; thus the solution of the potash compound evapo- 

 rates in an atmosphere of boric methide. Nevertheless, even by this 

 method the potash compound could not be obtained in a state of 

 perfect purity, the numbers obtained on analysis indicating only re- 

 motely the formula 



KO+B(C 2 H 3 ) 3 . 



Boric methide is also readily absorbed by solution of neutral car- 

 bonate of potash, bicarbonate of potash and potash boric methide 

 being apparently formed. Although boric methide and potash unite 

 with remarkable energy, they are separated by acids with the greatest 

 readiness ; even carbonic acid in the presence of water can expel boric 

 methide from its potash compound ; thus if an aqueous solution of 

 potash boric methide be passed into carbonic acid standing over mer- 

 cury, the acid gas soon becomes replaced by pure boric methide. 



Soda boric methide, baryta boric methide, and lime boric methide 

 are similar bodies produced by the absorption of boric methide gas 

 by caustic solutions of soda, baryta, and lime j they are all readily 

 soluble in water and react alkaline. 



