252 
PHENOMENA OF WINTER. 
coming into contact with the red-hot mass, Mr. London suggested this method 
of economising coals many years ago. 
A second method is to introduce a small tube with a fan-like orifice, through 
which a volume of the waste steam of a boiler might be impelled upon the gene- 
rated smoke. On this principle the locomotive steam-engines are constructed; and 
by the decomposition of watery vapour, oxygen and hydrogen gases are liberated 3 
and come in aid of the fire ; the one acting as a supporter or exciter of combustion, 
the other as an actual combustible. 
Wheresoever we can conveniently apply such true principles of Chemistry, and 
bring them to bear on practice, we do the utmost service to Science and Art, by 
justifying the former in removing the blind prejudices of its opponents, and 
establishing the latter upon a base far more satisfactory than that of empirical 
routine. 
The operation of hot water in warming houses by means of a tank and water- 
channels becomes daily more satisfactory, and for the following reasons : — • 
1. The heat produced is more natural, in so far as it approaches to the moist 
exhalations produced by solar power upon damp soil in hot countries. 
2. It is entirely free from sulphurous gas and vapour of carbon diffused from 
the common brick flue, and — 
3. It is more equable, and maintains a corresponding temperature in every 
part of an erection. 
At the same time, it should appear, that, as a medium of bottom-heat, it can 
by no means compete with that produced by dung, tan, or leaves, in fruit-growing ; 
though it may answer perfectly well in the propagation-house. 
There are those who adhere to the old brick flue ; and certainly there is a 
method of building by which every purpose may be effected, combining great and 
efficient power with considerable equability of radiation and diffusion of heat. 
This we shall attempt to describe from inspection of a house wherein there is one 
that was erected a* few months since. 
A common oven-furnace was built outside of, and close to, one corner of the 
back wall : if this oven were of cast iron, as once before recommended in a former 
article, it would never require rebuilding or repair. From the furnace the flue 
enters by a neck, which takes a diagonal direction for about a yard-and-a-half ; 
it then turns short to the right or left, nearly two yards within the wall of one end, 
running in a corresponding direction with it. The entire flue is shown in the 
following ground plan, where F is the furnace and its steps, (en) is the diagonal 
entering flue, with its neck ; the bent arrows indicate the course of the flue 
throughout its four courses — -the last terminating in a diagonal length, which enters 
the chimney built over the furnace ; this course (ex) is parallel with that of the 
entrance. The space within the flue courses is divided by a flue also, governable 
by three dampers, that drop in at the three places marked, o, and are raised by 
