162 



HEATING AS APPLIED IN HORTICULTURE. 



is left open for the admission of cold 

 air, which, being heated in passing the 

 sides of the furnace, flows into the flue, 

 increasing the draught, and carrying in 

 a considerable quantity of heat. Two 

 bricks are left movable over the door 

 frame b b, for the purpose of taking 

 out the soot. Fig. 177 shows section 



Fig. 177. 



of the ash-pit a a; fire-place bb; and 

 boiler c c. This boiler presents a very 

 considerable surface to the fire, the lower 

 part being exposed on all sides excepting 

 the end next the furnace door, and the 

 upper part of it along its bottom and one 

 end. The whole of the upper surface of 

 the boiler, by being uncovered, excepting 

 where the 4-inch side of the flue rests, is 

 giving out its heat to the house. 



Cruikshanks' mode of heating by hot 

 water. — Mr Cruikshanks has detailed his 



method at length, accompanied with the 

 necessary illustrations, in "The Horticul- 

 tural Society's Transactions," vol. i. p. 

 513, new series. A condensed account 

 of it appears in " Paxton's Magazine," 

 vol. ii. p. 249, from which we make the 

 following extract : — " The writer suggested 

 the mode of heating the water to a friend 

 in France, who had built a small green- 

 house in front of his dining-room, where 

 there was no convenient place to erect 

 the brickworkfor a common boiler, nor any 

 chimney into which a flue could be turned. 

 It occurred to him that, by having a small 

 cylinder boiler constructed like those ori- 

 ginally employed in the high-pressure 

 steam-engine, containing the furnace in a 

 smaller cylinder within the first, and sur- 

 rounded by the water, no brickwork 

 would be required; and that by burning 

 a mixture of charcoal and cinders, the 

 inconvenience of smoke would be avoided, 

 and sufficient draught obtained by a 

 moderate length of stove pipe passing 

 through the roof. This plan was adopted, 

 and answered completely. 



Fig. 178 is a vertical longitudinal sec- 

 tion ; a b c d the outer cylinder or boiler, 

 3 feet long and 1 foot in diameter ; e the 



m 



m 



fire-place ; / the door, lined with a mix- 

 ture of fire-clay and pumice-stone ; g the 

 ash-pit, furnished with a drawer of sheet- 

 iron. The fire-place and ash-pit are con- 

 tained in the inner cylinder, which is half 

 the length of the boiler, and 9 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: I is 

 a cylinder for supplying the boiler with 

 water, and allowing for its expansion 

 when heated ; m m the water pipes, con- 

 nected with the boiler by screws or 

 at o o. The pipes are elliptical, 



which shape combines in some measure 

 the strength of the circular with the ex- 

 tended surface of the flat form. The pipes 

 are only 12 feet long, but the circulation 

 is so rapid that the boiler would serve 

 for a much greater length ; n is an air- 

 pipe. 



" This small apparatus has answered so 

 well, and appears to offer so many advan- 

 tages over a boiler set in brickwork, that 

 the author has been led to consider how 

 the plan might be improved upon, and 

 applied to heating houses of larger 

 dimensions with any sort of fuel. This 

 might probably be accomplished by con- 

 structing the apparatus according to one 



