SPIRIT OF DISCOVERY.


* * * * *

_Heating with Hot Water._

Mr. A.M. Perkins has communicated to the _Gardeners' Magazine_ the
details of his plan for heating hot-houses by the circulation of hot
water in hermetically sealed tubes of small diameter. Upon the economy
of the plan, Mr. Loudon observes:--"With respect to the power of the
one-inch tubes, it has been demonstrated by a mathematician and chemist
of the very first authority, that as much will be effected by one of Mr.
Perkins's one-inch tubes, heated to 300° as by one of the three-inch
tubes, employed in any of the ordinary modes of heating by hot water
when heated to 180°." A second advantage of Mr. Perkins's mode for
hot-houses, is the small space which the pipes occupy. A third advantage
is, that the water may be circulated without regard to whether the tubes
are below or above the level of the fire-place. "But, however favourable
this plan may be for heating hot-houses, the advantage for that class of
structures are as nothing compared to those which it offers for heating
_dwelling-houses_ and all kinds of _manufactories_. This will be
understood at once, when it is stated that the water may be circulated
under ordinary circumstances of attention to the fire, at from 300° to
600°; and, with extraordinary strength of pipe, and application of fuel
to a still higher degree. It is found that 400° will roast meat. The
workmen in the bank-note printing-office of Messrs. Perkins and Bacon