ce of the air on the pendulum.
Or, again, we have the example of a water-wheel: first the water in the
reservoir, being higher than the wheel, has an amount of potential
energy. This is converted into kinetic energy in striking against the
paddles, and after this we have potential energy again produced by the
action of the fly-wheel.

By the principle of conservation of energy, if we consider the whole
universe, not our planet alone (for its heat and energy are continually
diminished to some slight degree), we find that _no energy is lost_.

Force is recognised as acting in two ways: in _Statics_, so as to compel
rest, or to prevent change of motion; and in _Kinetics_, so as to
produce or to change motion; and the whole science which investigates
the action of force is called _Dynamics_.

All this is of course pure mathematics, and I have made these elementary
observations for the benefit of my younger hearers, the students of this
University. My grave and reverend seniors will pardon, I am sure, the
repetition of facts well known to them for the sake of those who are
less informed than themselves.

Now before I proceed further, I will endeavour to point out that these
elementary truths of physical science hold good in our social system.
Each individual is a mass, acted on by numerous forces, capable of
'doing work,' which work can be measured and his velocity calculated.
Some individuals have a vast _potential energy_; that is to say, from
their position and station in the social system, they have a power which
is capable of producing work which a less exalted individual has not.
Like the weights in an eight-day clock, or the water in a reservoir,
they have a capacity for doing work, owing to the position to which
they have been raised. How vast the influence of a Primate or a Premier,
a General or a King! And yet their power is chiefly potential energy,
arising from the position they occupy, not from the individuals
themselves. Schiller has described this in poetical language, which,
strange to say, is mathematically correct:

'Yes, there's a patent of nobility
Above the meanness of our common state;
With what they _do_ the vulgar natures buy
Their titles; and with what they _are_, the _great_.'

Other forces may have raised these men to their exalted positions; but
their influence is due to their height, their potential energy. Placed
on a lower level, they would cease to have that power. Ho