Q. E. D. | Page 5

violent
external force that makes the inside burst open, as it were, we seem to
be able to make pieces fly off from the atoms, these pieces being then
projected into space with enormous force and velocity. There are
theories galore of the structure of the atom; but as Prof. E.P. Lewis has
said, most of these theories are so impossible as to be absurd, or so
speculative that "they suggest no experimental tests for their
validity."[2] Just at present Rutherford's theory of the structure of the
atom is quite popular. This postulates a nucleus composed of a group of
positive units and electrons, with an excess of the positive charges
equal to half the atomic weight, with an equal number of electrons
circulating about this nucleus in rings. Bohr's theory, which is not very

different from this, has perhaps even more friends, and it is supported
by the remarkable discoveries of the lamented Moseley. But we must
not take such theories too seriously. As Kayser has said, any true theory
of the make-up of the atoms must assume an absolutely full and perfect
knowledge of all electrical and optical processes, and is therefore
beyond our dreams. Or as Professor Planck said in his Columbia
lectures, we are not entitled to hope that we shall ever be able to
represent truly through any physical formulæ the internal structure of
the atom.
[Footnote 2: _Nature_, April 5, 1917.]
III
2. We must now take up the second phase of our subject, the problem
of the origin of matter.
Before we knew anything of radioactivity we could have dismissed
such a subject briefly by quoting the law of the conservation of matter,
which says that matter can neither be created nor destroyed by any
means known to science. By our knowledge of radioactivity we can
make our answer a little more learned, a little less abrupt, but none the
less discouraging to the advocate of the development hypothesis. We
can tell how the elements of high atomic weight, such as uranium and
thorium, are constantly giving off particles and are thus by loss or
decomposition being changed over into other elements, such as radium,
niton, polonium and lead. But our new knowledge compels us
ultimately to give the same answer as before, namely, that _we still do
not know how matter ever could have originated_, except that "in the
beginning" it was called into existence by the fiat of Him whom we
Christians worship as our God, the Creator. Thus we reach the
conception of the universe as that of a great clock gradually running
down, which is certainly the antithesis of that picture so long held
before us by the advocates of the development theory.
Uranium is a rather rare element, though known for over a hundred
years, and has an atomic weight of 238.5. In decomposing it gives off
first a helium atom, weight 4; and after this action has been repeated
three times the substance left is radium, atomic weight about 226.4.
Thus radium is simply uranium after it has lost three helium atoms.
Radium in its disintegration gives off three kinds of particles, namely,
helium atoms (positively electrified), [Greek: b]-rays or electrons, and

[Greek: g]-rays, the latter being identical with the X-rays, and having
penetrating power sufficient to carry them through six inches of lead or
a foot of solid iron. The final stage in this process of disintegration is
the ordinary element lead, in which condition the atoms seem to have
reached relative stability. Whether or not our stock of lead, with our
other common elements that are not radioactive, was originally
produced by the disintegration of these other elements, is merely a
matter of conjecture. We know nothing at all about it.
The length of time it takes for half the atoms of an element to change is
called its "life" or period. The periods of most of the radioactive
substances have been calculated, that of uranium being very long. The
calculated period of radium is 2,500 years, while that of polonium is
only 202 days, and that of niton 5.6 days. These unquestioned facts,
together with the enormous amount of heat evolved by the
disintegration of these substances (that from radium being about
250,000 times the heat evolved by the combustion of carbon), have
thrown a great deal of doubt upon the older estimates of the age of the
earth.
The discussion of the details of these theories would be unprofitable.
But through the mists of all these conflicting theories and probabilities
two facts of tremendous importance for our modern world emerge in
clear relief, namely, that the grand law of the conservation of matter
still holds true, and hence that the matter of our world must have had
an origin at some time in the past