Lab
Library
Journal
Shop
Sign in
to keep
Share image
1
177
The Story of Alchemy and the Beginnings of Chemistry
·
M. M. Pattison Muir
153
In
the
year
1896,
the
French
chemist
Becquerel
discovered
the
fact
that
salts
of
the
metal
uranium,
the
atomic
weight
of
which
is
240,
and
is
greater
than
that
of
any
other
element,
emit
rays
which
cause
electrified
bodies
to
lose
their
electric
charges,
and
act
on
photographic
plates
that
are
wrapped
in
sheets
of
black
paper,
or
in
thin
sheets
of
other
substances
which
stop
rays
of
light.
The
radio-activity
of
salts
of
uranium
was
proved
not
to
be
increased
or
diminished
when
these
salts
had
been
shielded
for
five
years
from
the
action
of
light
by
keeping
them
in
leaden
boxes.
Shortly
after
Becquerel's
discovery,
experiments
proved
that
salts
of
the
rare
metal
thorium
are
radio-active.
This
discovery
was
followed
by
Madame
Curie's
demonstration
of
the
fact
that
certain
specimens
of
pitchblende,
a
mineral
which
contains
compounds
of
uranium
and
of
many
other
metals,
are
extremely
radio-active,
and
by
the
separation
from
pitchblende,
by
Monsieur
and
Madame
Curie,
of
new
substances
much
more
radio-active
than
compounds
of
uranium
or
of
thorium.
The
new
substances
were
proved
to
be
compounds
chemically
very
similar
to
salts
of
barium.
Their
compositions
were
determined
on
the
supposition
that
they
were
salts
of
an
unknown
metal
closely
allied
to
barium.
Because
of
the
great
radio-activity
of
the
compounds,
the
hypothetical
metal
of
them
was
named
Radium.
At
a
later
time,
radium
was
isolated
by
Madame
Curie.
It
is
described
by
her
as
a
white,
hard,
metal-like
solid,
which
reacts
with
water
at
the
ordinary
temperature,
as
barium
does.
Marker
Marker
Fine marker
White-out
Fine white-out
Circle
Paint
Unmarker
Hand
Scalpel
Dice
Sieve
Purify
Undo
Redo
Start over
