uilibrium
of the air and sets that in motion.

Certain physicists deny that evaporation has anything to do with
atmospheric electricity. They tell us that it is caused by the arrest of
the energy of the sunbeam by the clouds and vapor in the upper
atmosphere. We admit that a part of the energy is so arrested, and is
stored, for the time, in moisture globules by a process of cloud
evaporation to transparent vapor again. Yet this does not hinder the
same process from going on at the surface of the earth wherever there is
water or moisture. But they tell us that the electroscope does not show
any signs of electrification in the evaporated moisture. Of course it
does not. The electroscope is not made to detect the presence of energy
except when set free as electricity.

A wound-up spring does not seem to be electrified, but if it is released
the energy stored in it will be transformed into electricity if the
conditions are right. Just so, the energy required to put the moisture
spherule into a state of strain is latent until some power releases it,
when it reappears as active energy of some form.

We have now followed the relation of heat to water from a point 10
degrees below freezing up to where it was forced into its original
gases, oxygen and hydrogen. These gases have stored in them a wonderful
amount of potential energy. When one pound of hydrogen and eight pounds
of oxygen unite to form water the mechanical value of the energy given
up at that time in the form of heat is represented by 47,000,000 pounds
raised to one foot in height. And this is the measure of the energy that
was put into nine pounds of water to force it from a state of vapor into
its constituent gases. After the combination of the gases into a state
of vapor the temperature sinks to that of boiling water. The amount of
energy given up in condensing the nine pounds of vapor into nine pounds
of water is equal to 6,720,000 foot-pounds. If this nine pounds of water
is now cooled from the boiling point to 32 degrees Fahrenheit we come to
the final fall, where the potential energy that is stored in the
operation of melting ice is given up suddenly at the moment of freezing,
which in nine pounds of water is 993,546 foot pounds.

Professor Tyndall, in speaking of the amount of energy that is given up
between the points where the constituent gases unite to form nine pounds
of water and the point where it congeals as ice, says: "Our nine pounds
of water, a