356 Mr. J. Davy’s Account of some Experiments 
silicated fluoric acid gas by water, and which, on account of 
the separation that occurs of part of the silex, may, with 
greater propriety, be called subsilicated fluoric acid. For this 
purpose, 43.21 cubic inches, barom. 30.4, therm. 50, or 44 
cubic inches at common temperature and pressure, were suc- 
cessively added, two cubic inches at a time, to one cubic inch 
of distilled water in a small jar over mercury. The whole of 
this, the gas being pure, was readily condensed. The tem- 
perature was somewhat raised. The silex precipitated, formed 
a gelatinous mass of a blueish colour, which had absorbed all 
the water like a sponge, so that none appeared fluid. This 
gelatinous mass was carefully transferred to a filter, and 
washed w ; ith distilled water till it w 7 as rendered insipid and inca- 
pable of reddening litmus paper. It retained its blueish hue only 
whilst moist. When dried and ignited, it was in thin lamellae, 
and of a snow r -white colour, and surprisingly bulky. It weigh- 
ed 7.33 grains, and was found to be pure silex. Thus it 
appears that the subsilicated fluoric acid formed by the decom- 
position of 44 cubic inches of silicated fluoric acid gas contains 
7.33 grains of silex less than the gas itself. Consequently 
independent of w^ater, which no doubt is essential to this acid, 
100 parts of it seem to consist of 
54.36 silex 
45.44 acid 
100.00 
I have endeavoured to ascertain what quantity of silicated 
fluoric acid gas a given quantity of water will condense. In 
one instance T *- 9 - of a cubic inch of distilled water absorbed 51 
cubic inches, barom. 30.5, therm. 60. The gas was added to 
