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177
The Story of Alchemy and the Beginnings of Chemistry
·
M. M. Pattison Muir
116
In
addition
to
these
advantages,
the
phlogistic
theory
was
based
on
experiments,
and
led
to
experiments,
the
results
of
which
proved
that
the
capacity
to
undergo
combustion
might
be
conveyed
to
an
incombustible
substance,
by
causing
it
to
react
with
some
other
substance,
itself
combustible,
under
definite
conditions.
The
theory
thus
prepared
the
way
for
the
representation
of
a
chemical
change
as
an
interaction
between
definite
kinds
of
substances,
marked
by
precise
alterations
both
of
properties
and
composition.
The
great
fault
of
the
theory
of
phlogiston,
considered
as
a
general
conception
which
brings
many
facts
into
one
point
of
view,
and
leads
the
way
to
new
and
exact
knowledge,
was
its
looseness,
its
flexibility.
It
was
very
easy
to
make
use
of
the
theory
in
a
broad
and
general
way;
by
stretching
it
here,
and
modifying
it
there,
it
seemed
to
cover
all
the
facts
concerning
combustion
and
calcination
which
were
discovered
during
two
generations
after
the
publication
of
Stahl's
books.
But
many
of
the
subsidiary
hypotheses
which
were
required
to
make
the
theory
cover
the
new
facts
were
contradictory,
or
at
any
rate
seemed
to
be
contradictory,
of
the
primary
assumptions
of
the
theory.
The
addition
of
this
ancillary
machinery
burdened
the
mechanism
of
the
theory,
threw
it
out
of
order,
and
finally
made
it
unworkable.
The
phlogistic
theory
was
destroyed
by
its
own
cumbersomeness.
A
scientific
theory
never
lasts
long
if
its
fundamental
assumptions
are
stated
so
loosely
that
they
may
be
easily
modified,
expanded,
contracted,
and
adjusted
to
meet
the
requirements
of
newly
discovered
facts.
It
is
true
that
the
theories
which
have
been
of
the
greatest
service
in
science,
as
summaries
of
the
relations
between
established
facts,
and
suggestions
of
lines
of
investigation,
have
been
stated
in
terms
whose
full
meaning
has
gradually
unfolded
itself.
But
the
foundations
of
these
theories
have
been
at
once
so
rigidly
defined
and
clearly
stated
as
to
be
incapable
of
essential
modification,
and
so
full
of
meaning
and
widely
applicable
as
to
cover
large
classes
of
facts
which
were
unknown
when
the
theories
were
constructed.
Of
the
founders
of
the
lasting
and
expansible
theories
of
natural
science,
it
may
be
said,
that
"thoughts
beyond
their
thoughts
to
those
high
bards
were
given."
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