INTRODUCTORY LECTURE. 
655 
and of exhibiting all the freshness of youth. Now, however 
much we may feel inclined to ridicule the notions and objects 
of the alchemists, we cannot, at the same time, fail to admire 
them for the indefatigable energy and perseverance Avhich 
they brought to bear on their undertakings—qualities which 
it would be well for us of the present age to emulate. The 
labours of the followers of alchemy were not attended by 
such futile results as one might at first sight imagine. It is 
true they utterly failed, in spite of numerous assertions to 
the contrary, in accomplishing their principal object, but we 
rhust not forget that they discovered many substances Avhich 
to this hour are, and probably ever will be, invaluable, in 
consequence of their utility. Thus, among other bodies, the 
alchemists discovered a number of acids; these they caused 
to act on metallic and other substances, and so produced 
various compounds which became, and still are, valuable as 
medicines. 
You will, perhaps, better comprehend the truth of this 
assertion Avhcn I inform 3 mu that we are indebted to the 
alchemists for the common mineral acids, calomel, corrosive 
sublimate, some of the preparations of antimony, as Avell as a 
host of other important remedial agents. Although the 
alchemists discovered a great many substances and facts, 
the advances which they made were fitful and slow, in con¬ 
sequence of their being unacquainted with the laws regulating 
the phenomena they observed. 
It was only after Priestly and Scheele, nearly a century 
ago, had discovered oxygen, that Lavoisier and certain other 
French chemists, as well as our own countryman, Dalton, 
laid the foundation of modern or scientific chemistry, by 
investigating and establishing the beautiful laws Avhich we 
now know governs the combination and decomposition of all 
the materials out of which Nature has constructed her three 
kingdoms. So long as the older chemists had no fixed prin¬ 
ciples to guide them in their practice, their labours were 
followed by irregular and uncertain results, and the progress 
which they made was extremely tardy; but so soon as 
the “laws of combination^’ were established, chemical dis¬ 
coveries began to accumulate rapidl^q and man)" of these 
discoveries have received such important, various, and general 
applications, that chemistry stands unrivalled among the 
departments of human knoAvledge, as an example of the 
immense stimulus which may be given to an art by knowing 
and applying the principles governing its practice ; in short, 
as an example of the wisdom of not relying upon empiricism 
alone, but of bringing to bear on a calling a judicious admix- 
