give
an
lated.
substances
which
differ
in
chemical
properties
of
radio-activity,
and
welds
the
time,
the
in the
in radio-active
.e uranium.
known
that
actinium,
like
radium,
gives
rise
polonium
that
lead,
polonium
is
produced
at
only
a
rays,
and
has
apparently
a
very
slow
period
of
transformation.
Commercial
preparations
of
undergo
spontaneous
transformation
and
are
to
be
regarded
untransformed
after
a
time
T,
the current-
this
view,
the
process
of
ionisation
by
rays,
was
small
If
n
ions
are
liberated
per
extremely rapid.
It is
positive
and
negative
ions
in
most
cases
have
velocity
of
the
is
given
by
\og
e
-r
dr
7 .
W
dt
the
electrodes,
and
thus
disappear
from
the
gas.
a
strong
uniform
electric
field.
The
small
number
of
drops
produced
without
the
the
conductivity
of
the
gas
before
and
after
passage
through
the
tubes.
In
this
way,
correcting
if
necessary
for
the
force
dpjdx
is
unity.
If
now
an
of
}\y
1
of
the
gas
mass
breaks
up
into
a
positive
and
negative
charge,
each
of
which
of
a
gas
at
standard
temperature
and
pressure
is
for a
approach
were
an
electrical
charge
atom
of
matter,
electrical
mass
due
to
its
motion
is,
in
general,
small
compared
with
of
an
in a
10
4
equal
to
velocity
round
the
ring,
the
radiation
of
energy
is
much
work.
The
general
arrangement
is
clearly
seen
in
Fig.
12.
The
observed
either
by
the
telescope
advisable
to
oscillated
irregularly
about
a
mean
position.
of
radia-
tion.
Such
a
standard
can
be
readily
prepared
by
a
method
first
used
by
McCoy*.
Some
uranium
Fig.
21.
Fig.
21.
Some
large
radius,
but
they
are
rapidly
absorbed
after
traversing
a
distance
material,
the
a
rays
must
consist
of
a
photographic
plate
placed
at
a
small
angle
with
the
more
intense
4
electrostatic
units
in
a
strong
electric
field.
This
quantity
of
electricity
is
small,
a
throw
of
obser-
vation.
measure
accurately
the
between CA
and B
always
numerically
tube
in
the
open
air.
seen
later
that
Bragg
more
accurately
range
and
the effect of
of
placing
a
thin
interpret
such
photographic
results
with
great
caution.
66.
Absorption
appreciable
current
was
observed
radium
itself,
the
a
particles
entered the
range
in
traversing
the
active
matter
itself.
The
shape
of
curve
diminution
in
the
number
of
a
particles
near
the
end
of
their
path
offers
a
reasonable
explanation
of
the
rapid
decline
in
the
ionisation
thick
layer
of
radio-active
matter,
but
the
expression
film of
a few
standard
pressure.
The
latter
number
for
different
pressures.
Some
of
his
results
are
given
in
the
following
table
50
8
particles
7
cms.
per
second.
removal of
were
concentrated
on
the
negative
plate
showing
that
they
spheric
pressure
was
about
1/10
mm.
Hahn*
and
magnetic
field
the amount of
zinc
sulphide
screen
S
interval between
successive a
a
particles
follows
a
1
1
average
life
of
about
1/5
second.
This
7
rays
is
usually
small
compared
cathode
rays
carry
with
them
a
negative
charge,
while
Lenard
an
exhausted
space,
it
gains
a
about
a
number
of
ft
particles
It is
10
10
ft
particles
were
expelled
per
second
dotted
line
average
ionisation
produced
by
a
cathode
'
energy
are,
on
an
average,
small
compared
high
atomic
weight
scatters
back
a
much
larger
proportion
of
the
particles
43*5
thickness
of
gold
0002
cm.
It
must
be
borne
in
ft
rays
which
approach
to
the
constituent
electrons
or
measure of the
greater
than
that
observed
x 10
approximately
homogeneous
beams,
the
rays
deduced
from
the
change
rays depends
velocity
for
swift
13
rays.
It
is
of
in
velocity
corresponds
to
a
marked
change
in
the
energy
and
penetrating
power
of
the
trans-
mitted
particles.
For
example,
the
rays
of
velocity
ionisation
10
mms.
a
change
to
/A
mms.
The
relative
values
of
/A
compared
incidence
ciHetyeiica
radiation.
Preliminary
experiments
were
for
the
most
part
be
expected
if
the
ft
rays
are
emitted
equally
at
each
point
radiation
was
found
to
increase
data,
quantity
and
quality
of
the
secondary
7
more
marked
than
for
7
rays.
characteristic radiation
when X
emergence.
103.
E which
was in
generally
observed
for
7
rays,
but
we
have
seen
that
Gray
has
or
7
rays
and
the
/3
rays.
It
suggests
why
the
/3
particle
excited
by
a
7
ray
travels
theories. The
the
ionisation
produced
by
them
is
subject
that
certain
substances
can
emit
several
types
question
whether
X
rays
and
7
rays
rays
glass
tubes
in
which
radium
is
kept
are
rapidly
coloured.
On
heating
the
tube,
a
strong
luminosity
is
observed,
and
the
colour-
ation
to
a
large
extent
disappears.
The
peculiarity
of
many
of
these
bodies
its
composition.
Other
kinds
of
glass
are
coloured
brown
or
yellow.
in X
as much colouration
rays,
when
exposed
to
light
the
colour
fades
away
the rod. In
of
radiation
was
produced
by
naked
drops,
the
opalescence
a
rays
gases
solution and
and then
large quantity
results.
The
experiments
are
Willows
and
PeckJ
elements. Since
and
water
present
photographically
very
active
solution
and
precipitating
the
longer
active,
sight
products
which
have
been
separated
it.
The
activity
of
a
rays
added
strong
confirmation
to
the
hypothesis
of
atomic
weight
less
than
that
of
the
parent
atom.
These
new
itself,
a
process
of
transformation,
very
similar
correctness
by
that the radiations
decay
with
the
greatest
possible
accuracy.
The
methods
adopted
to
determine
the
decay
may
be
conveniently
small
gasometer
over
mercury.
At
various
intervals,
a
definite
volume
of
compared
two
a
particles
at
nearly
the
amount
of
the
compound
in
a
extent
by
increasing
the
expose
a
large
surface
for
the
emanation
to
escape.
fairly large
temperature
of
the
spiral,
and,
in
consequence,
the
l
observed
for
the emana-
one-
the
number
d?N
for each
Loschmidtf
in
1871,
in
his
investigations
mixed.
Diffusion
emanations
varied
greatly
in
various
liquids.
The
liquid
was
contained
of
very
to
second.
Actinium
A
to
be
independent
of
the
pressure.
With
still
further
lowering
of
the
pressure,
the
activity
on
the
cathode
steadily
diminished,
and
at
a
pressure
of
1/10
pass
through
the
gas
before
their
velocity
carriers,
the
writerf
determined
their
velocity
deposit
was
prepared
by
dissolving
the
mass
the
equations
(5)
and
(6).
The
relative
numbers
of
[CH.
The
complete
T
products
emit
a
rays.
Since
the
periods
of
transformation
there is
[CH.
conditions,
the
energy
making
a
particle
was
roughly
proportional
to
its
range.
The
range
of
the
a
particles
at
standard
pressure
and
15
C.
latter must
For
example,
thorium
and
ionium,
radium
are
chemically
inseparable.
171.
experimentally
that
detail
by
Berry
J.
absorption
formation
between
uranium
and
radium,
further
used
by
Boltwood
does
not
involve
uranium
and
If
this
were
the
case,
escape
into
the
air.
I
gives
the
total
amount
of
emanation
in
arbitrary
units
in
one
gram
of
the
mineral,
corrected
10 ~
7
gram.
This
is
expressed
in
that
for
Joachimsthal
pitchblende.
Marckwald
minerals,
the
evidence
as
a
whole
strongly
supports
unaltered
minerals,
*
the
radium
atom.
Assuming
the
correctness
6
constant
which
depends
to
pump
the
gases
It to of
emana-
tion,
supposed
monatomic,
would
be
expected
considering
the
uncertainty
the standard
employed by
of
five
determinations
giving
values
227,
226,
225,
220,
218.
The
agree-
of
emanation
available
occupied
about
3
cms.
length
193.
Analysis
to
be
slightly
from
the
practical
case
where
the
body
is
exposed
to
a
In
this
case,
the
average
a
particle
from
short
ex-
posure,
that
the
experimental
and
calculated
values
exposure
is
consequently
proportional
to
k\.
2
Q
10
minutes,
while
the
amount
of
radium
C
reaches
a
maximum
in
35
minutes.
absorbing
screens
is
shown
in
Fig.
111.
The
maximum
ft
aluminium.
of a
equilibrium
off from
shown
to
consist
being
added
D
present
after
atoms
with
actinium.
not same
some
extent
by
fractional
crystallisations
of
the
double
nitrate
of
the
rare
earths
and
magnesium,
lanthanum.
not to
derived
from
radium
C
2
branch
product,
radium
formed
per
second
in
a
mineral,
can
be
approximately
calculated
Later
Meyer
and
v.
Schweidlerf
showed
formation of
D was
of the
Meyer
rise of
absorbed
are
not
very
different.
Barratt
by
the
scintillation
method
found
the
ranges
of
the
a
particles
from
respectively.
Geiger
and
Nuttall
by
the
emanation
under
ordinary
conditions
is
due
to
equal
to
be
737
days.
Later
observations
have
shown
in
equi-
librium
in
the
mineral.
On
the
other
hand,
the
activity
of
the
elapsed
for
1895.
Shortly
after
the
discovery
of
argon
antiquity,
it
was
reason-
able
to
suppose
of
hydrogen
from
millimetres,
and
229.
Production
OP
HEAT
561
purpose
radium
and
flask,
the
difference
in
pressure
was
reversed.
In
order
to
keep
the
apparatus
at
a
constant
temperature,
the
two
flasks
were
immersed
Experiments
gram
calories
per
hour,
OF HEAT
of
radium
can
be
accounted
for
by
taking
into
consideration
the
energy
the
energy
of
the
ft
rays
have
been
uncertain
magnitude
to
be
expected
from
preparation
of
polonium
were
made
by
Duane
measure
of
the
difference
of
pressure
between
A
of
potassium
the other
the
release
of
a
small
quantity
of
radium
emanation
into
the
experi-
activity.
Suppose,
however,
the
product
of
the
uranium
from
the
amount
of
lead,
but
varied
widely
in
different
minerals.
This
variation
is
to
be
expected
product
of
208*5.
supported by
product
by
precipitating
barium
as
sulphate
in
the
solution
or
active matter
absorb
completely
the
minute
quantity
of
the
product.
For
example,
mesothorium
2
is
separated
from
rneso-
thorium
by
precipitating
all
series.
-22V
Logarithm
particles
of
short
range.
It
is
that found
by Geiger
complexity,
for
three
times
greater.
It
is
a
region
times
compared
in a
small fraction of
effect on
[OH.
radium
or
thorium
emanation.
This
was
the
amount
of
active
matter
present
in
the
atmo-
sphere.
land
areas,
but
progressively
diminish
with
height
above
snow.
amount
of
emanation
per
cubic
in
at
a
height
of
100
metres,
the
intensity
should
be
only
potential
gradient
of
one
volt
per
cm.
Ions
of
this
type
are
present
of
positive
to
negative
was
emanation.
of the
of
Salins-Moutiers.
Curie
and
Laborde
the
soil,
so
important
factor
in
considerations
by
Struttf,
who
determined
the
quantity
of
radium
present
in
a
number
of
representative
rocks.
For
this
purpose,
definite
interval,
the
solution
rocks
and
sea-water.
The
results
of
Strutt
have
been
confirmed
by
the
experiments
of
Eve
and
borne
out
by
the
observations
of
Joly
6
cals.
per
year.
years
the
radium
were
uniformly
distributed
throughout
the
whole
volume
of
active
matter
which
would
give
rise
final
temperature
0,
however,
is
increased
by
Stormer.
Later
Vegard||
suggested
lead
plates
comparing
quantities
of
radium,
completely expelled
from
the
leak,
when
of
cases the
show two
of,
224
range
of
a
particle,
165
scattering
of
ft
rays,
213
absorption
of
ft