883 Abstract of 'Mr Faraday’s Experiments on trie 
a long tube perfectly dry, and closed at one end, being exhausted, was filled! 
with it ; more sulphurous acid was then thrown in by a condensing syringe, 
till there were three or four atmospheres ; the tube remained perfectly clear 
and dry, but oh cooling one end to 0°, the fluid sulphurous acid condensed, and 
in all its characters was Hke that prepared by the former process. 
“ Sulphurous acid vapour exerts a pressure of about two atmospheres at 
45° F. Its specific gravity was nearly 1.42. 
“ Sulphuretted Hydrogen .- — A tube being bent, and sealed at the shorter end, 
strong muriatic acid was poured in through a small funnel, so as nearly to fill 
the short leg without soiling the long one. A piece of platinum foil was then 
crumpled up and pushed in, and upon that were put fragments of sulphuret 
of iron, until the tube was nearly full. In this way action was prevented un- 
til the tube was sealed. If it once commences, it is almost impossible to close 
the tube in a manner sufficiently strong, because of the pressing out of the 
gas. When closed, the muriatic acid was made to run on to the sulphuret of 
iron, and then left for a day or two. At the end of that time, much proto- 
muriate of iron had formed, and on placing the clean end of the tube in a mix- 
ture of ice and salt, warming the other end, if necessary, by a little water, 
sulphuretted hydrogen in the liquid state distilled over. 
“ The liquid sulphuretted hydrogen was colourless, limpid, and excessively 
fluid. It did not mix with the rest of the fluid in the tube, which was no 
doubt saturated, but remained standing on it. When a tube containing it was 
opened, the liquid immediately rushed into vapour ; and this being done un- 
der water, and the vapour collected and examined, it proved to be sulphuret- 
ted hydrogen gas. As the temperature of a tube containing some of it rose 
from 0® to 45°, part of the fluid rose in vapour, and its bulk diminished ; but 
there was no other change : it did not seem more adhesive at 0° than at 45°. Its 
refractive power appeared to be rather greater than that of water : it decidedly 
surpassed that of sulphurous acid. The pressure of its vapour was nearly 
equal to 17 atmospheres at the temperature of 50°. 
u The specific gravity of sulphuretted hydrogen appeared to be 0.9. 
“ Carbonic Acid . — The materials used in the production of carbonic acid, 
were carbonate of ammonia and concentrated sulphuric acid ; the manipulation 
was like that described for sulphuretted hydrogen. Much stronger tubes are 
however required for carbonic acid than for any of the former substances, and 
there is none which has produced so many or more powerful explosions. Tubes 
which have held fluid carbonic acid well for two or three weeks together, have, 
upon some increase in the warmth of the weather, spontaneously exploded 
with great violence ; and the precautions of glass masks, goggles, &c. which 
are at all times necessary in pursuing these experiments, are particularly so 
with carbonic acid. 
« Carbonic acid is a limpid colourless body, extremely fluid, and floating 
upon the other contents of the tube. It distils readily and rapidly at the dif- 
ference of temperature between 32° and 0°. Its refractive power is much less 
than that of water. No diminution of temperature to which I have been able 
to submit it, has altered its appearance. In endeavouring to open the tubes 
at one end, they have uniformly burst into fragments, with powerful explosions. 
« Its vapour exerted a pressure of. thirty -six atmospheres, at a temperature 
of 32®. 
