ts temperature above that point.

In illustration of the power which our bodies have to resist the effects
of external heat, Sir Charles Blagden, with some other gentlemen, made
several very curious experiments. He remained for some time in an oven
heated to a temperature not much inferior to that of boiling water,
without suffering any other inconvenience than a profuse perspiration,
which he supported by drinking plentifully.

EMILY.

He could scarcely consider the perspiration as an inconvenience, since
it saved him from being baked by giving vent to the excess of caloric.

CAROLINE.

I always thought, I confess, that it was from the heat of the
perspiration that we suffered in summer.

MRS. B.

You now find that you are quite mistaken. Whenever evaporation takes
place, cold, you know, is produced in consequence of a quantity of
caloric being carried off in a latent state; this is the case with
perspiration, and it is in this way that it affords relief. It is on
that account also that we are so apt to _catch cold_, when in a state of
profuse perspiration. It is for the same reason that tea is often
refreshing in summer, though it appears to heat you at the moment you
drink it.

EMILY.

And in winter, on the contrary, tea is pleasant on account of its heat.

MRS. B.

Yes; for we have then rather to guard against a deficiency than an
excess of caloric, and you do not find that tea will excite perspiration
in winter, unless after dancing, or any other violent exercise.

CAROLINE.

What is the reason that it is dangerous to eat ice after dancing, or to
drink any thing cold when one is very hot?

MRS. B.

Because the loss of heat arising from the perspiration, conjointly with
the chill occasioned by the cold draught, produce more cold than can be
borne with safety, unless you continue to use the same exercise after
drinking that you did before; for the heat occasioned by the exercise
will counteract the effects of the cold drink, and the danger will be
removed. You may, however, contrary to the common notion, consider it as
a rule, that cold liquids may, at all times, be drunk with perfect
safety, however hot you may feel, provided you are not at the moment in
a state of great perspiration, and on condition that you keep yourself
in gentle exercise afterwards.

EMILY.

But since we are furnished with such resources against the extremes of
heat or cold, I should have thought that all climates would