The San Francisco call., 1896-11-01
What Is an Atom :?


1t is strange that great scientists should
allow little thing like an atom to bother
them, but they do. A recent writer has
given it as his opinion that there IS no
other department of scientific research
which shows SO strikingly mans tremen-
dous ignorance of nature as this bit OF in
finite minutia
It is freely admitted that the most pro-
found and diligent research has failed to
develop anything like adequate knowledge
as to what the little atom really is.
What he does is another matter. Long
and learned disquisitions have been writ
ten about that-how it is his tremendous
activity under the influence OF heat that
moves the engine, the little atom beating
against the piston and so driving 1t for
ward.
The atom, however, is not dependent
upon heat for its activity, for it keeps up
most exciting game of tag, even in the
more constrained limits of a cold piece of
iron. To be sure, our dull senses are un-
able to discover the fact. Neither our sight
nor our touch reveals it.
But if our organs were several million
times more acute they would be able to
distinguish a constant upheaval in what
otherwise appears to US a solid, immova-
BILE substance.
The individual molecule, however, has
/ large room for exercise in the small spaces
away down beyond our sense of touch.
Lord Kelvin says the atom is quite
measure ble-is not too small TO be capable
Of having its exact dimensions flxed by
| figures. And by way OF illustrating what
his figures mean he says that if drop of
water were magniied into the size of this
globe of ours and the atoms that compose
it were magnifed of course in proportion
the atom would appear somewhere be-
tween the size of a shot and the size of
a cricket bali.
-Four lines of argument" he says,
founded on observation, have led to the
conclusion that atoms, or molecules, are
not inconceivably. not immeasurably
small. use the words 'inconceivably'
and immeasura bly, advisedly. That
which is measurable is not inconceiv.
able, and therefore the two words consti-
tute tautology. We leave inconceiya-
bleness, in fact, to ometaphysicians. ~ =
The general results of the four lines of
reasoning to which I have referred,
founded respectively on the unduIatory
theory of light, on the phenomena of con-
tact electricity, on capillary attraction
and on the kinetic theory of gases, agree
in showing that the atoms or molecules of
ordinary matter must be something like
the 10000, 600 or from the 1-1O000 900 to
the 1-1O0, 900 of a centimeter in di-
ameter."
And here is Lord Kelvin's confession
concerning the atom:
'The chemists do not know what is TO
be the atom; for instance, whether hydro
gen gas is to consist of two pieces of mat
ter IN union constituting one molecuIe,
and these molecules flying about, or
whether single molecules, each indi-
visible, or at all events undivided,
IN chemical action, constitute the struc-
ture. L shall not go into any such ques-
tons at all, but merely take the broad
view that matter, although we may con-
ceive it to be infinitely divisible, is not in
finitely divislble without decom position"
Whether we can divide pieces of glass
into pieces smaller than the hundred
thousandth of a centimeter in diam eter
and so on without breaking 1t up, and
make it cease to have the properties of
glass, just as a brick has not the property
of brick wall, is a very practical oues-
ton.
Absolute continuity distinguishes mat
ter and space as it distinguishes time.
Moments, the atoms of time, can be
divided infinitely. so, also, he says, space
may be, but molecules of matter, he thinks.
reach point in their division where thew
lose their quality.
Butscientists have been discovering new