Dr. Playfair’s Lecture on the Great Exhibition of 1851. 21 
acid character of the one and the alkaline character of the other 
would wholly disappear in the resultant. Chemistry, therefore, 
in its present state, as Mills has shown, is not so much a deductive 
as an experimental science. Before it could be applied to the 
purposes of Industry, its experience had to accumulate, and its 
teachings to be appreciated and systematized. This accumulation 
of experience has been going on from the time of Tubal-Cain 
until now, and every day, in adding new facts to the stores, ma- 
terially augments its powers. It is not, therefore, surprising that 
it is one of the last of the sciences which, asa branch of sys- 
tematized knowledge, has offered its services to man; yet, during 
its short existence as a separate science, it has increased human 
resources and enjoyments to a greater degree than any of its elder 
sisters. If I can show you this by proofs derived from the Ex- 
hibition, it will naturally follow, that the study of Chemistry is 
essential to those engaged in manufacturing industry. 
he wants of civilization and the effects of competition require 
the effective application of increased power, both with regard to 
economy of labor and of time; and, in the gratification of these 
wants, e is aconstant aim to render objects apparently of 
little value useful and productive. ‘These, the benefits conferred 
upon industry by mechanical science, as shown by Babbage and 
others, are also afforded still more strikingly by her younger sister, 
Chemistry. Examining the various applications of Chemical 
Science to manufactures, they naturally divide themselves into 
the following three heads, which I therefore adopt as the basis of 
my Lecture, 
1. Chemical appliances which have added to human power, 
either by furnishing substitutes for mechanical contrivances, or - 
by affording tools and methods of arriving at results formerly 
impossible, ; 
2. Methods of producing economy of time, generally resulting 
from a constant tendency to simplification. 
ethods of utilizing products apparently worthless, or of 
endowing bodies with properties which render them of i 
ue to industry 
Vulean produced his works more economically than the mere 
mortal Asecmer of his time, by availing himself of the fires 
of Mount Etna for his forges. The possibility to do what pre- 
