90 Mr. Davy's Lecture on some nezv analytical Researches 
this substance ; but I am inclined to consider it as a compound 
of the olive coloured oxide of boracium, and an oxide of the 
fluoric basis. 
In examining the dry fluoric acid gas, procured in a process 
similar to that which has been just described, it gave very 
evident marks of the presence of boracic acid. 
As the chocolate coloured substance is permanent in water, 
it occurred to me that it might possibly be producible from 
concentrated liquid fluoric acid at the negative surface in the 
Voltaic circuit. 
I m,ade the experiment with platina surfaces, from a battery 
of two hundred and fifty plates of six inches, on fluoric acid 
the densest that could be obtained by the distillation of fluor 
spar and concentrated sulphuric acid of commerce, in vessels 
of lead. Oxygene and hydrogene were evolved, and a dark 
brown matter separated at the deoxydating surface; but the 
result of an operation conducted for many hours, merely 
enabled me to ascertain that it was combustible, and produced 
acid matter in combustion ; but I cannot venture to draw the 
conclusion that this acid was fluoric acid, as it was not impos- 
sible that some sulphureous, or sulphuric add might likewise 
exist in the solution. 
I heated the olive coloured inflammable substance, obtained 
from the boracic acid, in common fluoric acid gas in a plate 
glass retort ; the temperature was raised till the glass began 
to fuse ; but no change, indicating a decomposition, took 
place. 
I heated six grains of potassium with four grains of pow- 
dered fluor spar in a green glass tube filled with hydrogene ; 
there was a slight ignition, a minute quantity of hydrogene 
