ration.

Evaporation does harm in the Spring-time, because it produces cold, just
when we most want heat. How it produces cold, is not so readily
explained. The fact may be made as evident as the existence of sin in
the world, and, possibly, the reason of it may be as unsatisfactory.

The books say, that heat always disappears when a solid body becomes a
liquid; and so it is, that the air always remains cool while the snow
and ice are melting in Spring. Again, it is said that heat always
disappears, when a fluid becomes vapor. These are said to be laws or
principles of nature, and are said to explain other phenomena. To a
practical mind, it is perhaps just as satisfactory to say that
evaporation produces cold, as to state the principle or law in the
language of science.

That the fact is so, may be proved by many illustrations. Stockhardt
gives the following experiment, which is strikingly appropriate:

"Fill a tube half full of water, and fasten securely round the bulb
of it, a piece of cloth. Saturate the cloth with cold water, and
then twirl the tube rapidly between the hands; presently the water
in the tube will become sensibly colder, and the degree of cold may
be accurately determined by the thermometer. Moisten the cloth with
ether, a very volatile liquid, and twirl it again in the same
manner as before; by which means, its contents, even in Summer, may
be converted into ice."

It is very fortunate for us, that our Spring showers are not of ether;
for then, instead of thawing, our land would freeze the harder! The heat
of the blood is about 98 deg.; yet man can endure a heat of many degrees
more, and even labor under a Summer sun, which would raise the
thermometer to 130 deg., without the temperature of his blood being
materially affected, and it is because of perspiration, which absorbs
the surplus heat, or, in other words, creates cold. It is said, too,
that on the same principle, if two saucers, one filled with water warm
enough to give off visible vapor, the other filled with water just from
the well, are exposed in a sharp frosty morning, that filled with the
warm water will exhibit ice soonest. Wine is cooled by evaporation, by
wrapping the bottle in wet flannel, and exposing it to the air.

If, after all this, any one doubts the fact that evaporation tends to
produce cold, let him countenance his skepticism, by wetting his face
with warm water, and going into t