es on the score of economy, which will prevent their
total supercedure until some equally cheap and effective method shall be
found, to take their place. It cannot be questioned that houses of
moderate extent can be heated at much less expense for the original cost
of apparatus by the flue system than by any other now before the public.
Flues have the advantage over steam or hot water in their power to
generate heat and supply it to the green or hot house in a very short
space of time, and with this apparatus, the fires may be allowed to go
out on mild and bright days in winter, with the certainty that heat can
be easily and quickly commanded at nightfall. Steam cannot be generated
quickly, and the hot water apparatus requires considerable time to get
into full operation, with the usual amount of fuel.

Among the serious objections to the use of flues, is the unequal
distribution of heat throughout the house; the parts near the furnace
being overheated, while at the chimney it is scarcely warm. This
difficulty can be partially obviated by the use of materials in the
construction of the flues, of different thicknesses,--being made thick
and heavy at the furnace, and gradually becoming thinner and lighter as
it extends towards the chimney. Again, flues generally require more fuel
than a hot water apparatus, and moreover, they are unsightly in an
ornamental house, and with the best care in their construction and
management, they do not give entirely satisfactory results.

Earthenware drain-pipe is frequently employed for flues, and when care
is taken to prevent their cracking by the excessive heat near the
furnace, they answer the purpose very well. When properly secured at
their joints they prevent the escape of gaseous matter more perfectly
than brick flues.

Flues should be elevated a few inches above the floor, and supported by
bricks, to allow all the radiating surface to act upon the atmosphere of
the house, and should have, in order to secure sufficient draft, a
gradual rise through their whole length from the furnace to the entrance
into the chimney.

The furnace should be built inside the house at one end, with the fire
and ash-pit doors opening into a shed outside, to prevent any escape of
gas into the house while replenishing the fire. It will be necessary to
place the furnace low enough to allow a proper rise to the flue. If the
flue be made to rise immediately from the furnace about one foot, it may
then b