344 EXPERIMENTS ON THE RELATION 
sphere blown in its middle, and its other extremity iia 
into pure water, in a glass pneumatic cistern. 
When the part ar the green glass tube where the turnings 
Jay, was brought to ignition very visible in day-light, it was 
moved forward with its supporting semi-cylinder of iron, by 
imperceptible degrees. Thus the salt was exhaled from the 
bottom, so slowly, that its vapour, in traversing the numerous 
convolutions of the iron laminz, was almost entirely decompo- 
sed into its constituent gases. The muriatic acid gas was (as 
formerly stated) partly condensed into muriate of iron, partly 
into liquid acid in the bulb, and partly into the water in the 
glass cistern. 
Of permanent gaseous matter 106 cubic inches were collec- 
ted, after the whole salt had been sublimed from the bottom of 
the tube. One hundred cubic inches of these were found by 
explosion with oxygen in my eudiometer, to consist of 77 hy- 
drogen + 23 azote. Hence the total product of 106 cubic 
inches was composed of 81.62 hydrogen, and 24.38 azote. 
Now 20 grains of sal ammoniac contain 9.66 gr. of ammo- 
nia. And since 18.178 gr. of this alkaline gas occupy the vo- 
lume of 100 cubic inches, but are resolvable into double that 
volume, or 200 cubic inches of constituent gases; therefore 
9.66 gr. of ammonia will give by their entire decomposition 
106.28 cubic inches of gaseous products. Of these, one-fourth 
according to M. Gay Lussac’s theory of volumes, is azote, and 
three-fourths hydrogen ; or 26.57 of the former, and 79.71 of 
the latter. 
Hence we see that the total bulk of evolved gases, coincides 
very nearly with the quantity known to exist in the ammonia. 
The azote, therefore, is not concerned in the production of the 
water. The deficiency of about two cubic inches of this gas, 
may be fairly ascribed to a small portion of the salt having 
escaped 
