No. 3-] ATOMS AND MOLECULES. 573 
The heavy-lined circle represents the atom, which is certainly 
an elastic body, whatever may be its dimensions; and if it be . 
subjected to pressure or impact, will yield like 
the prong of a tuning-fork or the mouth of a 
bell; and if spherical or circular, will assume 
an elliptical outline; and if free to move, will 
execute a series of elliptical phases at right 
angles to each other, as represented by the dot- 
ted lines in the figure. This change of form 
is a mechanical necessity when bodies are elastic, and that 
quite independent of what the form of the body may be. The 
evidence for the statement that this is the real character of the 
motion that constitutes what is called heat comes from Spec- 
troscopy, especially that of heated gases, where molecules have 
time to execute vibrations between impacts, in which case they 
give out radiations of definite wave lengths, and in harmonic 
series, which of course must be derived from the harmonic 
vibrations of the particles of matter that are heated. It has 
been demonstrated that the ultimate particles of matter, atoms, 
cannot be spherical in shape; and to-day the only theory of the 
constitution of matter we have is the Vortex Ring Theory of Sir 
William Thomson. One must either adopt that or be without 
any ; but evidence for its being a true theory is fast accumu- 
lating, and there has as yet no serious objection been offered to 
it from either physics, chemistry, or mathematics. 
It will be adopted for the purposes of this paper, and hence 
the diagram, Fig. 1, may be considered as a vortex ring capable 
of changing its form and vibrating with an amplitude determined 
by its size, thickness of ring, etc. Such an atom has a definite 
fundamental rate of vibration, and a series of harmonic rates 
which are 2, 3, 4... # times the fundamental rate, which is the 
one represented. It is to be noted that where such vibrations 
are taking place there are certain places upon the vibrating body 
where the motion is at a maximum, called the /oops, and also 
intermediate places where the motion is least, called xodes. 
In the diagram there are four of each. If the body has a series 
of harmonic vibrations, there will then be 2, 3, 4, and so on, 
number of times the nodes of the fundamental. The number 
of times such vibrations can occur among the atoms of matter 
is determined by dividing the velocity of light by the wave 
