South Bend news-times. (South Bend, Ind.) 1913-1938, 1918-12-07
What the World
Is Made Up of
BY GARRETT p. sERyIss.

"ii aIIcie on atoms. molecules.
electrons and ions" These names
appear so frequently now in news
papers. magazines and books that
everybody ought 20 have an elemen-
tary knowledge Of the things for
which they stand Some OF them
were never heard Of in schools which
people now in middle life attended.
Atom IS an old word conveying an
old idea, viz. that Of the existence
II ultimate. indivisible particles Of
which all things are composed. II
IS easy 20 see how the notion of
atoms arose. You ind that every
thing can be divided and split I'D in
/ 10 smaller and smaller particles. The
finest particles OF dust into which
a rock might be divided may be
separately invisible without a micro
scope. But both experience and rea-
son indicate that that is not the end
OF the division but that the dividing
process may be continued almost
without limit.
The question then arises. is there
actually a limit? Can matter be re-
/ duced 10 particles so small that fur
Their division is impossible? Even
the ancient Greek philosophers con
cluded that there was such a limit,
and they called the final. indivisible
particles atoms" l. e., things that
cannot be cut. but without under
taking to say just how small they
were.
This idea lived through the ages,
springing up again after every tenn
pOrary recession of man into bar
/ barism and ignorance, and at last il
became one Of the corner stones of
modern science. The late Lord Kel-
I win made a celebrated calculation Of
| the probable size of an atom. He, so
to speak. put it on the viewing stage
| Of the microscope Of the imagination
by means of graphic comparison.
Imagine" he said. "a raindrop
or a globe Of glass as large as a pea
TO be magni1ed up 10 the size OF the
earth. each constituent atom Che
used the word r1olecule, but we may
substitute atom for our present
purpose) being magnified in the same
proportion. The magnified structure
would be more coarse grained than
/ less coarse grained than a heap of
cricket balls" More recent calcula-
! tons given the diameter of the
smallest atom as about one-three-
/ hundred millionth Of an inch. The
] largest kind may have many times
that
With the atom it was until re-
! Gently supposed that subdivision
! ceased il was adopted as the chem
/ lists unit" and pra ctically remains
so still, although, as we shall see.
the theory of it's indivisibility has
proved to be erroneous. The great
! service that the conception Of ulti-
mate atoms has rendered TO chem
istry is in making clear the differ
ence between elementary and COM
pound substances. and rendering il
possible TO study the laws of chemi-
cal action.
Every substance made up OF only
one kind Of atoms is an element"
About S3 chemical elements are now
| known; consequently there are So
different kinds Of atoms.
! Molecules are groups Of atoms. so
that a moleCule is larger than an
atom of the same kind of substan nee
There are two sorts Of molecules.
] viz. those which consist Of only one
kind, or species, of atoms. and those
which consist Of atoms Of different
kinds united together. The first sort
Of molecules is found only i'm ele-
mentary substances, and the second
only i'm compound substances, l. e..
substances made up OF two or more
| chemical elements.
For the sake Of clearness il is
best, for ordinary purposes, 10 think
Of molecules only as the constituent
particles of compound substances.
/ Being composed of atoms Of differ
ent kinds. when such molecules are
broken up the compound substance
formed of them loses its identity,
land the separated atoms go back
into their elements
Water. for instance. is a com
pound substance, each OF whose
molecules consists Of one atom Of
the element oxygen combined with
1.-TWO atoms OF the element hydrogen.
When water is chemically decom-
posed. its individual molecules are
broken up and from each Of them
lis released one atom of oxygen and
two atoms OF hydrogen, but there
the ordinary process OF decomposi-
ton ceases and we cannot make an
other division by breaking up the
atoms.
Within quite recent times, how
ever. il has been discovered that the
apparently indivisible and unbreak-
liable atom really consist OF much
smaller particles revolving around
a center. or nucleus. and these
smaller particles which make up the
atom are called electrons. The aver
age diameter Of these excessively
minute things has been calculated as
labout one one hundred thOUsandth
of the diameter OF an atom! Elec-
irons carry. or consist Of, charges OF
negative electricity. and they are
believed to revolve, with immense
lepeed around nucleus charged with
positive electricity.
The revolving electrons together
with their nucleus constitute the
atom. An atom may be destroyed, or
rrere,ad IL, character hv the esca be