158 ACIDIFIABLE COMBUSTIBLES. 



Boron ] 

 Oxygen 1-7368 



The mean of these two experiments gives us the 



composition of boracic acid as follows : 







Boron 1 



Oxygen 2-128 



Now, I am persuaded that this comes nearer the 

 truth than any other analytical results which 

 have bee,n given to the public. 



The statement of Gay-Lussac and Thenard, 

 that boron, when converted into boracic acid, 

 only absorbs half its weight of oxygen, is most 

 certainly extremely inaccurate. Davy's result, 

 I believe to be about th part below the truth -, 

 but the result of the French chemists cannot be 

 much less than fths below the truth. 



In the second volume of the second series of 

 the Annals of Philosophy, I published a set of 

 experiments on boracic acid, from which I de- 

 duced 2*7,5 as the probable atomic weight of that 

 acid. But my experiments, which consisted in 

 the analysis of borax, were not quite conclusive, 

 owing to the difficulty of collecting and weighing 

 the whole of the boracic acid. I had not at that 

 time examined jluoboric acid gas with the re- 

 quisite attention. I have since found, that this 

 curious combination furnishes us with the means 

 of determining the atomic weight of boracic 

 acid with rigid accuracy. 



