on the Nature of certain Bodies. 47 
oxygene, was to the indestructible elastic fluid, as 2.5 
to 1. 
In this process, the heat applied approached to the dull red 
heat. The mercury, in the thermometer, stood at 62° Fahren- 
heit, and that in the barometer at 30.3 inches. 
In various experiments on different quantities of the fu- 
sible substance, in some of which the heat was applied to 
the tray in the green glass retort, and in others, after it had 
been introduced into the iron tube ; and in which the temper- 
ature was sometimes raised slowly and sometimes quickly, 
the comparative results were so near these that I have de- 
tailed, as to render any statement of them superfluous. 
A little more ammonia, and rather a larger proportion of 
inflammable gas,* were in all instances evolved when the iron 
tube was used, which I am inclined to attribute to the follow- 
ing circumstances. When the tray was brought through the 
atmosphere to be introduced into the iron tube, the fusible 
substance absorbed a small quantity of moisture from the air, 
which is connected with the production of ammonia. And in 
the process of heating in the retort, the green glass was black- 
ened, and I found that it contained a very small quantity of 
the oxides of lead and iron, which must have caused the dis- 
appearance of a small quantity of hydrogene. 
M. M.Gay Lussac and Thenard, it appears from the state- 
ment, had brought the fusible substance in contact with mer- 
cury, which must have given to it some moisture ; and when 
ever this is the case, it furnishes by heat variable quantities 
* The average of six experiments made in a tube of iron, is 2,4 of inflammable 
gas to 1 of uninflammable. The average of three made in green glass retorts, is 
2.3 to 1. 
