uly successful, a man must not
only be a practical enthusiast and a keen theorist; he must also be a
skilful experimentalist: his experiments and their results, if carefully
watched, deduced, recorded, and studied, will serve to guide him for the
future.

APPENDIX.

_On Heating, Ventilating or Aerating, and Covering._

Since the publication of the first edition of this work in 1844, the views
expressed in the second chapter, with reference to structures best adapted
for Cucumber culture in the winter season, have met with much
corroborative support. Respecting the questions of heating, ventilation,
and covering, a few more words may be added.

I have before recommended hot water tanks for supplying bottom heat, with
attached pipes for the circulation of hot water to warm the atmosphere. I
can see no reason for recommending any other arrangement now; for the
experience of successive years goes to show that hot water, applied on
sound principles, is, above all other means of heating, effective in its
operation; and as to the question of expense, raised as an objection to it
by some, it is sufficient to say, that, although one hot water apparatus
may be fitted up in an expensive manner, another may be rendered perfectly
successful in its operation, at the same time that it is extremely simple
in its arrangements, and correspondingly inexpensive in its cost.

A seeming error in the engraving, at p. 18, has been pointed out to me. In
the description of the sketch it is stated that, "a series of pipes
attached to the same boiler [which heats the tank] would supply the
requisite heat to the atmosphere." The sketch itself shows these pipes to
be considerably above the level of the water in the tank, and where they
could not, consistently with the other arrangements, be thus employed.
This may be explained thus:--the sketch was introduced rather for the
purpose of illustrating certain proposed arrangements, as regards bottom
heat and ventilation, than as furnishing an exact and detailed design for
a model structure; and thus it happened that the pipes were merely shown
to be placed at the front part of the house, to indicate that this was
their proper relative position. There would be no practical difficulty in
placing the pipes lower down, and nearly close to the front wall, so as to
admit of the proposed connection; all that would be required to effect
this, being to fix the slab, on which they rest--and which prev