to be preferred.[15]

FOOTNOTES:

[13] In cerebro-spinal meningitis, tuberculosis, and pneumonia, fresh
air is curative. Any person, sick or well, cannot have too much fresh
air. The windows of sleeping rooms should always be kept open at
night.--EDITOR.

[14] These outlets may be placed close to a chimney or heating pipes.
Warm air rises and thus will be forced out, allowing cool fresh air to
enter at the inlets.--EDITOR.

[15] The ordinary dwelling house needs no artificial methods of
ventilation. The opening and closing of windows will supply all
necessary regulation in this regard. The temperature of living rooms
should be kept, in general, at 70 deg. F. Almost all rooms for the sick
are unfortunately overheated. Cool, fresh air is one of the most
potent means of curing disease. Overheated rooms are a menace to
health.--EDITOR.

CHAPTER III

=Warming=

=Ventilation and Heating.=--The subject of the heating of our rooms
and houses is very closely allied to that of ventilation, not only
because both are a special necessity at the same time of the year, but
also because we cannot heat a room without at the same time having to
ventilate it by providing an egress for the products of combustion and
introducing fresh air to replace the vitiated.

=Need of Heating.=--In a large part of the country, and during the
greater period of the year, some mode of artificial heating of rooms
is absolutely necessary for our comfort and health. The temperature of
the body is 98 deg. to 99 deg. F., and there is a constant radiation of heat
due to the cooling of the body surface. If the external temperature is
very much below that of the body, and if the low temperature is
prolonged, the radiation of heat from the body is too rapid, and
colds, pneumonia, etc., result. The temperature essential for the
individual varies according to age, constitution, health, environment,
occupation, etc. A child, a sick person, or one at rest requires a
relatively higher temperature than a healthy adult at work. The mean
temperature of a room most conducive to the health of the average
person is from 65 deg. to 75 deg. F.

=The Three Methods of Heating.=--The heating of a room can be
accomplished either _directly_ by the rays of the sun or processes of
combustion. We thus receive _radiant_ heat, exemplified by that of
open fires and grates.

Or, the heating of places can be accomplished by the heat of
combustion being conducted th