250 
ON THE CONSTRUCTION AND HEATING OP HOT-HOUSES. 
charcoal and cinders, the inconvenience of smoke would be avoided, and sufficient 
draug-ht obtained by a moderate leng-th of stove pipe passing through the roof. 
This plan was adopted, and answered completely. 
Fig. 1. 
Fig. 1 is a vertical longitudinal section : A, B, C, D, the outer cylinder or 
boiler, three feet long and one foot in diameter ; E the fire-place ; F the door, lined 
with a mixture of fire clay and pumice-stone ; G the ash-pit, furnished with a drawer 
of sheet iron. 
The fire-place and ash-pit are contained in the inner cylinder, which is half the 
length of the boiler, and nine inches in diameter. From the back of the fire-place, 
an elliptical flue, H, proceeds nearly to the end of the boiler, then returns again 
towards the front, and passes out at I into the chimney K. L is a cylinder for sup- 
plying the boiler with water, and allowing for its expansion when heated : M M, 
the water-pipes, (shown in section fig. 2,) connected with the boiler by screws or 
flanges at O O. These pipes are elliptical, which shape combines in some measure 
the strength of the circular with the extended surface of the flat form. The pipes 
are only twelve feet long ; but the circulation is so rapid that the boiler would serve 
for a much greater length ; N is an air-pipe. 
Fig. 1. 
This small apparatus has answered so well, and appears to ofl'er so many advan- 
tages over a boiler set in brick-work, that the writer has been led to consider how 
the plan may be improved upon, and applied to heating houses of large dimensions; 
with any sort of fuel. This might probably be accomplished by constructing the? 
apparatus according to one or other of the plans of numbers 3 and 4, where the- 
