ot last one half as long as
though dry wood from a wood-house were used. 3. It is impossible to
preserve an even temperature. Sometimes it is too cold, and at other
times it is too warm; and this, with such means of warming, is
unavoidable. Scores of teachers have informed me that, in order to keep
their fires from going out, it was necessary to have their stoves
constantly full of wood, and even to lay wood upon the stove, that a
portion of it might be seasoning while the rest was burning. Aside from
the inconvenience of a fluctuating temperature, this is an unseemly and
filthy practice, and one that generates very offensive and injurious
gases.

Again: I have frequently heard the following and similar remarks: "The
use of stoves in our school-houses is a great evil;" "Stoves are
unhealthy in our school-houses, or in any other houses," etc. This idea
being somewhat prevalent, and stoves being generally used in our
school-houses, their influence upon health becomes a proper subject for
consideration.

Combustion, whether in a stove or fire-place, consists in a chemical
union of the _oxygen gas_ of the atmosphere with _carbon_, the
combustible part of the wood or coal used for fuel. Carbonic acid, the
vitiating product of combustion, does not, however, ordinarily
deteriorate the atmosphere of the room, but, mingling with the smoke,
escapes through the stove-pipe or chimney.

The stove, in point of economy, is far superior to the open fire-place
as ordinarily constructed. When the latter is used, it has been
estimated that nine tenths of the heat evolved ascends the chimney, and
only one tenth, or, according to Rumford and Franklin, only one
fifteenth, is radiated from the front of the fire into the room.
Four-fold more fuel is required to warm a room by a fire-place than when
a stove is used. Oxygen is, of course, consumed in a like proportion,
and hence, when the open fire-place is used, there is necessarily a
four-fold greater ingress of cold air to supply combustion than where a
stove is employed.

And, what is of still greater importance, when a fire-place is used, it
is impossible to preserve so uniform a temperature throughout the room
as when a stove is employed. When a fire-place is used, the cold air is
constantly rushing through every crevice at one end of the room to
supply combustion at the other end. Hence the scholars in one part of
the room suffer from cold, while those in the opposite part are
oppre