SECRETS
OF
SCIENCE.
241
ness,
it ceases
to contract
and
suddenly begins
to
expand
;
and
on
freezing,
is
found to
expand considerably.
3.
Cohesion
is
a
law
of
nature,
but
in
gases
one finds
expulsion
when
cohesion
ought
to take
place.
4.
In
the
downward
pressure
of solids and
fluids forca
is
always
in
proportion
to
weight,
but
in
the
hydraulic
paradox,
the
weight
of one
gallon
of water
can
be
made
to act with
the
pressure
of a thousand tons.
This is
strange.
5.
One
line
continuously approaching
another must
eventually
meet
that
other,
but
in
the
parabola
the
asymptote
continually
approaches
the
curve,
and
yet
Bcience
proves
plainly
that
it
never
will touch the
curved
line.
6.
Every
child
is
aware,
just
as well as if
he were a
member
of the
fire
brigade
in
a
large city,
that
water
quenches
fire
;
that there is
a
destructive
war
ever
being
waged
between the
elements
of water and
fire,
so
that,
water in sufficient amount
destroys
fire
;
in
a
word,
that
water and
flame
cannot
exist
together
in
the
same
place
;
yet,
it
is
a
fact,
that
oxy-hydrogen
light
will
blaze in
the
midst
of water
;
further
still,
water
reduced to
its
original
elements of
oxygen gas
and
hydrogen, produces
light
the
most brilliant and heat the most
intense,
by
igniting
the
gases
just
in
the
same
ratio of
combining
elements,
that
are
required
in
the
production
of
water from
the
union
of
oxygen
and
hydrogen gases.
7.
A
ray
of
light
viewed as
coming
from a
luminous
centre is
simple,
yet
by
means
of
a
solar
spectrum
it
is
resolved
into
those elements which
produce
the
primary
colours,
and
each
colour
or
subdivision of a
ray
of
light
is
itself
the
product
of a
number of
lines,
or of
undula-
tions.
The
length
of the
waves which
causes,
for
in-
stance,
the
red
ray
is
such,
that
it
would
take
thirty