dissolved; the Linnean Society, instituted under the
presidency of the learned Dr. Benjamin Smith Barton; the
Columbian Chemical Society, founded in 1811; the Academy of
Natural Science--all show the zeal for useful knowledge and
philosophical inquiry.... For the introduction of popular
chemistry, the citizens of Philadelphia are also indebted to
Doctors Rogers and Jones, and to Benjamin Tucker, who have
taught Chemistry with much zeal and talents."

Many attractions are found in the Philosophy of Experimental
Chemistry. The first discussion is that on Chemical Affinity. Two
experiments are introduced. In the first it is stated

"If equal parts, by weight, of sulphur and mercury be
introduced into a crucible, and in this situation exposed to
a sufficient heat; a compound will be formed, called
sulphuret of mercury."

In the second experiment the student is advised to

"Mix together sulphur and potash, and throw them into water;
the sulphur will separate. If the same articles be put into a
crucible and melted, and then thrown into water, the sulphur
as well as the potash will be dissolved."

And next comes the

"_Rationale._ In the first experiment there is an instance of
chemical action, as well as of single affinity, for the
sulphur and mercury would remain separate if heat was not
applied. In consequence of this agent, they unite into an
uniform whole, totally inseparable by mechanical means, and
possessing characters distinct from either of its constituent
parts.

"In the second experiment, the union of sulphur with potash
is effected by heat; for if a sulphuret was not formed, no
solution of the sulphur would take place. Hence it is that
chemical action is the consequence of a power, without which
it could never ensue, and with which it always acts in
unison. This power is affinity."

Then it is remarked:

"Chemistry is a science, which has for its object to discover
the constituent properties of bodies, the result of the
various combinations, and the laws by which those
combinations are effected. Its operations being either
analytical or synthetical, consist of composition, or
decomposition. The laws which govern chemical changes have
been resolved into those of attraction or affinity. Affinity
of composition of chemical affinity differs from that of
agg