ous gases, sometimes escaping from flues,
and the substantial character and enduring qualities of the apparatus,
are important considerations in favor of this method of heating which
are not to be overlooked or underrated.

It is true that a house of a given size cannot as soon be brought to the
required temperature after the fire is first lighted, as by other modes
of heating, but when once in full operation greater regularity is
maintained, and if the fire should by any neglect go out, heat is still
radiated, often for several hours, before the pipes become entirely
cold.

For heating ornamental houses of glass, pipes are also to be
recommended on account of the little room they occupy and the neatness
of their appearance compared with the unsightly flues or tank. If
properly put up, the pipes never leak at the joints, as is the case
frequently with tanks, and scarcely need any repairs for years. The
first cost of apparatus for heating by hot water pipes exceeds that of
the other methods which we have named, but when we take into account its
great durability, economy of fuel, and the satisfactory results produced
in the growth of plants in houses heated in this manner, it must be
evident that this method is the cheapest in the end.

It is generally supposed that the heat obtained from steam or hot water
pipes necessarily contains moisture. For those who have had any
experience in the use of these methods of heating, it is needless to say
that such is not the case. To obtain moisture evaporation of water in
some manner in the atmosphere must be effected. This is provided for by
attaching to the pipes evaporating pans filled with water, by which the
moisture can be perfectly regulated and controlled. The capacity of the
boiler and the length of the pipes should be in proportion to the size
of the house to be heated, bearing in mind that it is better to have a
reserve of heating power for extraordinary occasions. In such cases
economy in fuel will be secured, as the fires will not be required to
be kept constantly burning brightly.

Fault is sometimes found with the apparatus when it lies entirely with
the proprietor of the establishment, who in his short-sighted economy,
has restricted the builder in the amount of pipe put into the apparatus.

CONSTRUCTION, &c.

The general plan of Horticultural structures may be as perfect as
possible, but if the details are not well carried out, and especially if
the workmans