10 
APPLICATION OF HEAT. 
among exotics, — beautiful China roses, the Cydonia Japonica covered with blossom, 
Berberis aquifolia protruding bloom-buds, and horse-shoe Pelargoniums scarcely touched 
by frost. What a contrast to the parched and lifeless blank of December, 1844 ! 
Yet, with all this charming opening beauty, the new year may bring with it a 
repetition of the more than Siberian asperity of 1838, when, after a Christmas sea- 
son mild as May, the frost set in on the 4th of January, and continued to advance 
till it reduced the mercury from two to four degrees ; and, as some stated, eight or more 
degrees below zero ! Frost has now, in fact, commenced, though mildly ; and with 
this remark, which may be proved of some consequence ere this paper meets the 
reader's eye, we come at once to the subject that claims particular notice at the 
approaching season of the year : — 
Occasions have offered themselves wherein the operations of forcing and protection 
have been dwelt on with some interest. The modes of heating have always appeared 
more or less objectionable, whether on the ground of wastefulness and want of power 
in the fuel, or of irregularity in the irradiation and distribution of heat. At length, 
however, a furnace has been discovered which appears to combine every appliance 
and advantage contended for. It is not exactly new, neither is it secured or 
restricted by patent, yet it does not appear to be much known at present. 
From the form of the apparatus it has been called the Saddle boiler ; and, so far 
as we may judge from repeated observation during the erection of a new propagation- 
house, it appears to possess every required quality for the radiation and perpetuation 
of heat. It consists of a double casing of cast-iron, eighteen or twenty inches long, 
and a foot deep from the roof, or arch, at top, to the fire-bars, both in the clear. It 
is of the figure of a good arched draining tile, and rests firmly upon the frame and cast- 
iron fire-bars, in front of which, and true to their level, is a strong iron plate, adapted 
so as to receive a charge of coals in front of the main body of fire. These coals be- 
come heated. The inflammable coal-gas being rarefied, expands, and passes off over 
the ignited red mass, in the condition of intensely heated flame ; thus consuming 
smoke, and heating the water with extreme rapidity. 
The furnace door is double, as is also the ash-pit door beneath it ; this latter 
being furnished with a revolving valve, to admit greater or less portions of air, 
or to exclude it entirely, supersedes the chimney register. 
The figure No. 1 exhibits the saddle boiler, b b, which (being of the dimensions 
referred to) is presumed to contain about seven gallons of water. Its appendages are, 
d d, the fire door and ash-pit door, set in brick work, and elevated a foot, or more, 
above the surface of the ground-level ; ex shows the upright exit, or flow pipe ; r r, 
the right and left return pipes ; and F, the oven,or fire furnace. This last is one 
with the boiler, forming its internal case, and therefore in immediate contact, 
throughout its inner surface, with the ignited materials. The fire runs the whole 
length of the oven, turns over the end, round the sides, and finally passes off in front 
of ex, which it heats, entering the chimney at a point above F, and in front of the 
tube ex. 
