19S Experiments on Muriatic Acid Gas, 
when the heat is applied, the hydrogen gas produced is expelled, 
with any muriatic acid gas not ‘acted on. 
In the principal experiment I employed, zine filings were used 
in preference to iron, from the consideration, that muriate of 
zinc is less volatile than muriate of iron, and therefore would ad- 
mit of a higher heat being applied to expel «ny water. One 
hundred grains of clean and dry zing filings were introduced, 
while warm, into the retort; the air was expelled, and muriatie 
acid gas was admitted liter the jar. Ou applying heat to the 
zinc, the retort, which was before perfectly dry, was bedimmed 
with moisture at its curvature, and small spherules collected at 
the top of the neck. ‘These inereased in size, and extended 
further as the experiment advanced. After a certain time, part 
of this disappeared in the interval of cooling, being absorbed by 
the deliquescent product ; but when the heat was again applied, 
it was renewed, and this in increased quantity, until at length, 
at the end of four days, during which heat had been frequently 
applied, the whole tube ‘ofthe retort, seven inches in length, was 
studded with small globules of fluid. When the heat had been 
raised high, a beautiful arborescent crystallization appeared in a 
thin film on the body of the retort, but no part of this reached 
the neck. ‘The retort was now detached; the gas it contained 
was withdrawn by a caoutchoue bottle; a small receiver was 
adapted ; and a slight heat having been applied, to expel a little 
of the air, the joining was made close by cement. The receiver 
was surrounded with a freezing mixture, and heat was applied 
by a choffer to the retort, as far as could be done without raising 
dense vapours. Globules of liquid, perfectly limpid, collected 
pretty copiously towards the middle and lower part of the neck, 
and the receiver, on being removed from the freezing mixture, 
was covered internally with a film of moisture. “The glo- 
bules in the neck of the retort were absorbed by a slip of bibu- 
lous paper, and the quantity was found to amount to 1-2 gr. 
The receiver being dried carefully, and weighed, lost by the dis- 
sipation of the moisture within, 0-4 grain. Distilled water, in 
whieh the bibulous paper was penecbadly was quite acid; it gave 
no sensible turbidness on the addition of ammonia, or of carbo- 
nate of soda, and held dissolved, therefore, merely pure muria- 
tic acid. The mass in the retort was of a gray colour, with 
mnetallic lustre, in loosely aggregated lamine, somewhat flexible. 
It weighed 114°8 grains, “Adding to this inerease of weight, 
which the zine had gained, the weight of the water and the hy- 
drogen gas expelled, it gives a consumption of muriatic acid gas 
of about 16°S grains, equivalent to about 43 cubic inches. Sup- 
posing the weight of water to be doubled, or nearly so, by sa- 
turation with muriatie acid, this gives che: product “of water in 
the 
