The central Presbyterian. [volume] (Richmond, Va.) 1856-1908, 1881-02-23
The Atomic Theory.

The following extract from Wurtz's
The Atomic Theory give as clear and
succlnct an account as we are acquainted
with of the vortex theory of atoms, which
now is gaining adherents:
In these later times a theory has
arisen which seems to give mathema-
tical demonstration, and even an expert
mental illustration, of the indivisibility,
or rather of the peculiar and eternal in
dlvlduallty OF atoms. | refer to the vor-
tex atoms of Sir William Thomson.
Chemists can form an idea of this
vortex motion by recalling to mind the
rings which rise in still air whenever a
bubble ofphosphoretted hydrogen bursts
upon the surface OF water, and the rings
which certain smokers are able to make
are familiar to all. An apparatus has
been constructed by which they may be
produced at will 1t is wooden box,
one side of which is furnished with a
circular opening and the other formed of
a tightly-stretched cloth. In the interior
OF the box fumes of salammoniac are pro-
duced, which are driven out by a sharp
blow on the elastic side. A ring of
smoke is then seen to issue from the open
ing and to move freely through the room.
In this ring all is motion; and, indepen-
IDENTIFY of the motion of translation the
smoke particles roll over each other and
execute rotatory motion in every sec
ton of the ring. These motions take
place from the interior toward the ex-
terror of the ring, in the direction of the
motion of translation, so that the entire
mass of air, or the smoke which forms the
ring, revolves continually round a cir
cular axis, which forms, as it were, the
nucleus of the ring. There is this re-
markable fact in this rotatory motion
that all the particles which are situated
upon one of the curves which can be
drawn in each section of the ring are in
dissolubly tied down to their circular
paths and can never quit them; SO that
the whole mass q the vortex ring will
be always formed of the same particles.
This theorem was proved by Helmholtz,
in 1858. This eminent physicist has
analysed the vortex motions which would
exist In perfect fluid free from all fric-
ton. He has proved that in such a me-
dunn vortex rings, bounded by a system
of vortex lines, are formed of an invari-
able quantity of the same liquid mole
cules, so that the rings can move, and
even change their form, without the con-
nection of their constituent parts even
being broken. They will continue to
revolve, and nothing will be able to
separate them, divide them, or destroy
them. Those existing in the liquid will
exist there forever, and new ones can
only be excited in it by creative act.
"The smoke-rings Of which we have
spoken above would give perfect repre-
sentation Of these liquid vortex rings if
they were formed and moved in per-
feet fluid. They are not so; but such as
can be formed can serve for the demon
stration Of some properties of matter in
vertex motion. They are endowed with
elasticity and can change their form.
The circle is their position of equih-
brium; and when their form is altered
they oscillate round this position and
finally reassume the circular form. But,
if we try to cut them, they recede before
the knife, or bend around it, without al
lowing themselves to be injured. They
give, therefore, a material representation
of something which would be indivisible.
And when two rings meet each other,
they behave like two solid elastic bodies
After the impact, they vibrate energeti-
cally. 1t is singular fact that when
two rings are moving in the same direc-
ton, so that their centres are situated
upon the same line and their planes per-
pendicular to this line, the hinder ring
contracts continually, whilst its velocity
increases; the ring in advance, on the
contrary, expands, and its velocity de-