The sun. [volume] (New York [N.Y.]) 1833-1916, 1903-07-12
Imtratomic Energy Unmeasura-
BILE Force OF Illuminate Nature.

ole FOrCe OF hnamhmaVc N@tuTc.
Perhaps no scientific discovery Of re-
cent times has awakened such general
interest as that Of spontaneous radiation.
When BECoUEREL showed that the sub
stance uranium was capable Of evolving
energy continuously without supply
Of any kind, the fundamental law Of the
conservation Of energy seemed seriously
shaken. Er nihilo nihil fit had become
an accepted dictum of science, alike for
matter and for energy; and to bring
either Of these into existence from moth
ing, seemed OF necessity to involve the
exercise of creative power.
Meanwhile investigations went on.
New substances were discovered, hith-
erto unknown to chemistry, possessing
this new property Of emitting energy
uninterruptedly and without any as
signable cause, to an extent a million
times greater than uranium could do.
Radium was found to emit excessively
minute corpuscles with such immense
velocity that the energy Of single mil
ligram Of them represents about three
and a half million foot tons! Actual
measurements have shown that this new
radio-element sends out every twenty
four hours thirty times az much energy
in the form Of heat as an equal weight OF
oxygen and hydrogen evolve when they
combine to form water; an amount
greater than is produced in any other
chemical reaction. The energy Of the
changes accompanying radio-activity,
therefore, must be enormous. RUTH
ERFoRD tells US that it is at least twenty
thousand times, and it may be million
times, as great as that of the most
intense molecular changes known; such,
for example, as that set free by modern
explosives
But since the carriers Of this energy
are moving particles, it was natural to
inquire whether this emission Of energy
must not necessarily result in CORE
spending loss of matter. So BECoURREL
calculated what this loss would be; and
he finds that single square centimstre
of radioactive surface will radiate into
space only single gram Of matter in q
billion years. To detect the infinitesimal
trace of matter thus emitted during the
time of an ordinary experiment would
seem entirely hopeless. And yet so
wonderfully has the delicacy of modern
instruments of research been increased
that, as we are told, if 900 grams of
thorium produced the thousandth part
af 80 ~
years, the amount from one gram in one
second could still be, as it actually 10,
easily detected by the electrometer.
This instrument, therefore, will detect
in one minute an amount of matter
which must accumulate for two million
years before it becomes sufficient to be
recognized by the chemical balance.
Inasmuch as the term rsdio.activity
represents simply the property which
certain bodies possess of emitting rays,
it is evident that the three radioactive
elements, uranium, thorium and radium,
are so called because they emit their
energy in this form. These rays consist
of material particles projected with
high velocity We are told that practi-
cally all the energy of radioactive sub
stance is emitted by two sorts Of rays,
one OF which consists Of negatively
charged particles, each having mass of
only one-thousandth of that of the atom
of hydrogen and moving with nearly the
speed OF light the other, which is by far
the more important, since it constitutes
about 80 per cent. of the total radiation,
consists Of positively charged particles,
whose mass is approximately that Of the
entire hydrogen atom whose speed is
less than one-tenth of the above value.
THOMSON has given the name corpus
Giles, which he considers to be electrons
or masses of electricity.
Since radio-activity is specific prop
erty of the chemical element itself which
exhibits it, and since during the process
this element is continually losing parti-
cles of it's substance, the changing system
involved must necessarily be the atom.
In any radioactive changes, therefore,
it must be the chemical atom which
undergoes disintegration. The system
which remains after the expulsion of
these heavy charged particles from it
must be lighter than before and must
possess different physical and chemical
properties from the original substance.
But rays may be again expelled from the
new body and so second new system
may result, and so on.
RUTHERFORD has shown us, for eX-
ample, that the emission of rays from
thorium is the accompaniment OF a con-
tinuous change of this element into new
kinds Of matter. The first product Of
this radioactive change he calls thorium
X. It has well-defned chemical proper
ties of its own, quite unlike those of
thorium. The expulsion of rays from
thorium X accompanies the production
OF a gaseous element, the so-called tho
rum emanation. This il a radioactive
gas capable Of liquefaction at 40 c..
remarkably inert chemically and resem-
bling the monatomic gases argon and
helum. Another loss of particles takes
place with the production of third
new substance, the so-called excited
activity, capable Of being volatilized at
hyed high temperature, and Of being
NAK bal - l.