ON CHEMISTRY. 
293 
Now, as steam aiul vapor are lighter than air, as clouds formed in 
the atmosphere Jloat in that medium, what can have prevented the 
air from becoming lighter by its admixture with the never ceasing 
accumulation of watery vapor, during a period of six weeks ? We 
see by facts of frequent occurrence that, drought, or evaporation do 
not depend altogether upon heat. A parching east wind will at 
times dry the ground much more effectually than the rays of a hot 
sun: hay will “make” much quicker on some occasions under a 
cloudy sky, than in bright sunshine. In showery weather the eva¬ 
poration (with a temperature of perhaps 50 to 60) will be vastly 
more rapid than during a clear sun and great thermometric heat. In 
October, I have seen the instrument at 70—73 degs.—the barometer 
at 30 inches, the heavens cloudless; and with all these requisites of 
perfectly fine weather, the evaporation has been trilling, the dews 
have been intense and durable, and every stone of a pavement has 
been covered with water! I shall not now insist upon other facts; 
sufficient have been alluded to—I trust—to induce thought and re¬ 
flection. Without asserting any thing, I venture again, and ur¬ 
gently, to suggest that, the watery vapors must either render the at¬ 
mosphere specifically lighter, in proportion to the quantity in which 
they are present; or that they enter into union, and become one with 
it, by a peculiar electric action. If my view be correct, then, in 
proportion as vapor is converted into air, the weight of that air must 
be increased, because its bulk is enlarged. I believe that this bulk 
is perpetually subject to changes; and that these alterations are at 
all times produced by the decomposition and reformation of the va¬ 
pors of the atmosphere. The agency, its mode of operation, and the 
proximate cause, are hidden secrets: we see not the machinery, and 
can only draw inferences from the observation of effects. 
Upon Heat, and its connection with the Phenomena of 
the Dew _Of Heat, its nature, substantiality, or immateriality, it 
must be acknowledged that, we ready know little or nothing. We 
may define terms, and conjecture with Lavoisier (as he stated in his 
memoir in 1777) that it is a material substance— for after atten¬ 
tively considering the phsenomena of attraction and repulsion, he 
conceived it “ difficult to comprehend these phaenomena without ad¬ 
mitting them as the effects of a real material substance, or very sub¬ 
tile fluid, which, insinuating itself between the particles of bodies, 
separates them from each other.” To this substance, the renowned 
father of modern chemistry applied the name of igneous fluid, (from 
ignis —latin for fire;) and the matter of heat. Subsequently, in 
