PART III.
Description of the Instruments and Operations of Chemistry.
INTRODUCTION.
In the two former parts of this work I designedly avoided being
particular in describing the manual operations of chemistry, because I
had found from experience, that, in a work appropriated to reasoning,
minute descriptions of processes and of plates interrupt the chain of
ideas, and render the attention necessary both difficult and tedious to
the reader. On the other hand, if I had confined myself to the summary
descriptions hitherto given, beginners could have only acquired very
vague conceptions of practical chemistry from my work, and must have
wanted both confidence and interest in operations they could neither
repeat nor thoroughly comprehend. This want could not have been
supplied from books; for, besides that there are not any which describe
the modern instruments and experiments sufficiently at large, any work
that could have been consulted would have presented these things under a
very different order of arrangement, and in a different chemical
language, which must greatly tend to injure the main object of my
performance.
Influenced by these motives, I determined to reserve, for a third part
of my work, a summary description of all the instruments and
manipulations relative to elementary chemistry. I considered it as
better placed at the end, rather than at the beginning of the book,
because I must have been obliged to suppose the reader acquainted with
circumstances which a beginner cannot know, and must therefore have read
the elementary part to become acquainted with. The whole of this third
part may therefore be considered as resembling the explanations of
plates which are usually placed at the end of academic memoirs, that
they may not interrupt the connection of the text by lengthened
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