etween man and man. Take, for example, the Force of public opinion. Of
what is it composed? It is the Resultant of all the forces which act
upon that which is generally designated the 'Social System.' Public
opinion is a compromise between the many elements which make up human
society; and compromise is a purely mechanical affair, based on the
principle of the Parallelogram of Forces. Sometimes disturbing forces
exert their influence upon the action of Public Opinion, causing the
system to swerve from its original course, and precipitating society
into a course of conduct inconsistent with its former behaviour; and it
is the duty of the Governing Body to eliminate as far as possible such
disturbing forces, in order that society may pursue the even tenor of
its way.

Professors, we have one great problem to solve; and all questions
social, political, scientific, or otherwise, are only fragments of that
great problem. All truths are but different aspects of different
applications of one and the same truth; and although they may appear
opposed, they are not really so; and resemble lines which run in
various directions, but lovingly meet in one centre.

Now, let us take for our consideration the secret influence which men
exert upon each other, apart from that produced by the power of speech
(although that would come under the same general law). As
mathematicians, you are aware that the undulatory theory of light and
heat and sound are now accepted by scientific men as the only sure basis
of accurate calculation. We know that the rays of light travel in waves,
and the equation representing the waves is

a 2[pi]
y = --- sin ------ (vt - r),
r [lambda]

where _y_ is the disturbance of the ether, _a_ the initial amplitude,
_r_ the distance from the starting-point, [lambda] the wave-length, and
_v_ the velocity of light. Sound and heat likewise have much the same
form of equation. Now, I maintain that the waves of thought are governed
by the same laws, and can be determined by an equation of the same form.
You are aware that in all these equations a certain quantity denoted by
[lambda] appears, and varies for the different media through which the
sound, or light, or heat passes, and which must be determined by
experiment Now, in my equation for brain waves, the same quantity
[lambda] appears which must be determined by the same method--by
_experiment_. But how is this to be done? After matur