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177
The Story of Alchemy and the Beginnings of Chemistry
·
M. M. Pattison Muir
17
The
atomic
theory
was
used
by
the
great
physicists
of
the
later
Renaissance,
by
Galileo,
Gassendi,
Newton
and
others.
Our
own
countryman,
John
Dalton,
while
trying
(in
the
early
years
of
the
19th
century)
to
form
a
mental
presentation
of
the
atmosphere
in
terms
of
the
theory
of
atoms,
rediscovered
the
possibility
of
differences
between
the
sizes
of
atoms,
applied
this
idea
to
the
facts
concerning
the
quantitative
compositions
of
compounds
which
had
been
established
by
others,
developed
a
method
for
determining
the
relative
weights
of
atoms
of
different
kinds,
and
started
chemistry
on
the
course
which
it
has
followed
so
successfully.
Instead
of
blaming
the
Greek
philosophers
for
lack
of
quantitatively
accurate
experimental
inquiry,
we
should
rather
be
full
of
admiring
wonder
at
the
extraordinary
acuteness
of
their
mental
vision,
and
the
soundness
of
their
scientific
spirit.
The
ancient
atomists
distinguished
the
essential
properties
of
things
from
their
accidental
features.
The
former
cannot
be
removed,
Lucretius
said,
without
"utter
destruction
accompanying
the
severance";
the
latter
may
be
altered
"while
the
nature
of
the
thing
remains
unharmed."
As
examples
of
essential
properties,
Lucretius
mentions
"the
weight
of
a
stone,
the
heat
of
fire,
the
fluidity
of
water."
Such
things
as
liberty,
war,
slavery,
riches,
poverty,
and
the
like,
were
accounted
accidents.
Time
also
was
said
to
be
an
accident:
it
"exists
not
by
itself;
but
simply
from
the
things
which
happen,
the
sense
apprehends
what
has
been
done
in
time
past,
as
well
as
what
is
present,
and
what
is
to
follow
after."
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