perpendicular column of rarefied particles are propelled forward with inconceivable rapidity, and the whole line of pipe attains a high degree of temperature in a few minutes, and, in less than an hour, arrives at its maximum of heat. The action is so powerful that the atmosphere in the building is speedily warmed to any temperature required, and should it be too hot, the circulation can be instantly stopped by means of the valves, and the temperature lowered to any point required.

This mode of heating is also applicable to dwelling-houses, any floor of which may be warmed by a boiler being placed in a remote corner of the basement story of the building, the pipes above in each floor being concealed behind the skirting, where the heat would escape through an open iron ornamental fret work, or foliage ornament, placed along the top of the skirting or place of the moulding, which produces a very beautiful and pleasing finish.

The superior advantage of this apparatus appears to consist chiefly in the boiler, an original invention of Mr. Coldridge's. It is customary with many manufacturers to use boilers of small dimensions, which are capable of absorbing but a very small part of the heat generated in the combustion of the fuel; consequently the greater part of the heat is carried up the chimney and expended to no purpose. To set this in a clear point of view, it may be necessary to observe, that as an equal quantity of cooled particles will be brought back by the returning pipe, as there were hot particles set in motion by the leading pipe; it follows, that in a boiler of very small dimensions, these cooled particles would occupy nearly the whole external surface, and would require to be re-heated at every successive circulation; whereas in the cylinder boiler, above described, these particles would occupy but a small space at the bottom, while the water above, being already heated, the circulation would proceed with greater rapidity. In other words, if the boiler be large, the particles of water would be heated with more rapidity than they could possibly circulate through the area of the pipe, and the result would be, that a surplus quantity of heated water would be retained in the boiler until the whole quantity in the boiler had attained a high degree of temperature, in which case the quantity of cooled particles brought back by the returning pipe would have but little effect in lowering the temperature of the whole mass, whilst the hot particles at the upper surface of the boiler would keep up the circulation without interruption, and the contrast of the temperatures between the leading and returning pipes, (on which the action depends,) would be consequently greater, or in the ratio of the difference between the proportions of a small boiler and a large one.

Some boilers have one pipe only, others two, for the ascending steam, which latter is the most consistent. We have seen some with three, and those of the most enormous and unnecessary size, seeming to have been made without any calculation as to the quantity of heat the pipes would convey. Note. Each steam-apparatus contains but one descending or condensing water-pipe, which enters at or near the bottom of the boiler, while the steam-pipes are always at the top.-(Author.)

ILLUSTRATIONS.

THE

ELEMENTARY DIAGRAMS OF DESIGN,

AND EXEMPLARS OF

THE VARIOUS STYLES OF DOMESTIC ARCHITECTURE

DISPLAYED AND DEFINED;

INCLUDING

THE APPROPRIATE FURNITURE,

GARDEN,

AND LANDSCAPE SCENERY OF EACH.