101 
on the Nature of certain Bodies. 
not redden vegetable blues, might be ascribed to a species of 
neutralization, by the oxide or inflammable body; but the 
same reasoning will not apply to the dry compounds which 
contain acid matter only, and which are precisely similar as to 
this quality. Let a piece of dry and warm litmus paper be 
moistened with the compound of muriatic and phosphorous 
acid, it perfectly retains its colour. Let it then be placed upon 
a piece of moistened litmus paper, it instantly becomes of a 
bright red, heats and devellopes muriatic acid gas. 
All the fluid acids that contain water are excellent conduc- 
tors of electricity, in the class called that of imperfect con- 
ductors ; but the compounds to which I have just alluded, are 
non-conductors in the same degree as oils, with which they 
are perfectly miscible. When I first examined muriatic acid, 
in its combinations free from moisture, I had great hopes of 
decomposing them by electricity ; but there was no action with- 
out contact of the wires, and the spark seemed to separate no 
one of their constituents, but only to render them gaseous. 
The circumstance likewise applies to the boracic acid, which is 
a good conductor as long as it contains water; but which, 
when freed from water and made fluid by heat, is then a non- 
conductor. 
The alkalies and the earthy compounds, and the oxides, as 
dry as we can obtain them, though non-conductors when solid, 
are, on the contrary, all conductors when rendered fluid by 
heat. 
When muriatic acid, existing in combination with phospho- 
rous or phosphoric acid, is rendered gaseous by the action of 
water, the quantity of this fluid that disappears, at least equals 
from one third to two fifths of the weight of the acid gas 
