"The first teacher of chemistry was Dr. Benjamin Rush ... who may justly be styled the father of chemistry in America. He commenced a course of lectures on this science in the then College of Philadelphia; and although chemistry at that day (1768) may be said to have been in its infancy, yet the Doctor did honour to the chair, the school, and his country. We now speak of him only as a chemist.... The advancement of chemistry in our city ... is also indebted to other institutions. The American Philosophical Society, the College of Physicians, instituted in 1787, the Medical Society, formed in 1771; the Chemical Society under the patronage of Doctors Woodhouse and Seybert, which has since been 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: