therefore possess a perpetuum mobile--a mechanism like a watch which
runs out and winds itself up--a force which is never
exhausted--competent to produce effects of the most powerful kind,
and self-renewed ad infinitum.

Many phenomena, formerly inexplicable, are satisfactorily explained
by these recently discovered properties of porous bodies. The
metamorphosis of alcohol into acetic acid, by the process known as
the quick vinegar manufacture, depends upon principles, at a
knowledge of which we have arrived by a careful study of these
properties.






LETTER III





My dear Sir,

The manufacture of soda from common culinary salt, may be regarded
as the foundation of all our modern improvements in the domestic
arts; and we may take it as affording an excellent illustration of
the dependence of the various branches of human industry and
commerce upon each other, and their relation to chemistry.