ETTER I

My dear Sir,

The influence which the science of chemistry exercises upon human
industry, agriculture, and commerce; upon physiology, medicine, and
other sciences, is now so interesting a topic of conversation
everywhere, that it may be no unacceptable present to you if I trace
in a few familiar letters some of the relations it bears to these
various sciences, and exhibit for you its actual effect upon the
present social condition of mankind.

In speaking of the present state of chemistry, its rise and
progress, I shall need no apology if, as a preliminary step, I call
your attention to the implements which the chemist employs--the
means which are indispensable to his labours and to his success.

These consist, generally, of materials furnished to us by nature,
endowed with many most remarkable properties fitting them for our
purposes; if one of them is a production of art, yet its adaptation
to the use of mankind,--the qualities which render it available to
us,--must be referred to the same source as those derived
immediately from nature.

Cork, Platinum, Glass, and Caoutchouc, are the substances to which I
allude, and which minister so essentially to modern chemical
investigations. Without them, indeed, we might have made some
progress, but it would have been slow; we might have accomplished
much, but it would have been far less than has been done with their
aid. Some persons, by the employment of expensive substances, might
have successfully pursued the science; but incalculably fewer minds
would have been engaged in its advancement. These materials have
only been duly appreciated and fully adopted within a very recent
period. In the time of Lavoisier, the rich alone could make chemical
researches; the necessary apparatus could only be procured at a very
great expense.

And first, of Glass: every one is familiar with most of the
properties of this curious substance; its transparency, hardness,
destitution of colour, and stability under ordinary circumstances:
to these obvious qualities we may add those which especially adapt
it to the use of the chemist, namely, that it is unaffected by most
acids or other fluids contained within it. At certain temperatures
it becomes more ductile and plastic than wax, and may be made to
assume in our hands, before the flame of a common lamp, the form of
every vessel we need to contain our materials, and of every
apparatus required to pursue our experiments.

Th