366 



Hints for Experiments. 



manner already strongly recommended, (p. 167.) Many small green-houses 

 and conservatories about .London, which are at present without flues or 

 fire-places, and, consequently, without good and healthy plants, might be 

 most economically and elegantly heated in this way. If the ponds and 

 tanks formed in kitchen-gardens for the supply of the watering-pot in the 

 warm season, were of suitable shapes and sizes to be covered with frames 

 and sashes, the water might be heated by immersed lamps or jets of burning 

 gas ; a floor of planks, flag-stones, or slates, on iron rafters, or of cast-iron 

 plates, might be formed over the water, on which to place the pots of 

 plants to be preserved, or the mould in which to grow cucumbers or 

 melons, or to force fruits or culinary vegetables. With the heat supplied 

 in this way, and retained by ample coverings of thatch or reeds, much 

 might be done. It is easy to conceive^the idea of a whole system of pits, 

 and what are called hot-beds,"built of brickwork, and heated by tanks of 

 water, instead of beds of dung. The lower parts of the walls of the pit, 

 and the bottom, or pavement, would require to be set in Roman cement, 

 and the mould for the plants must be supported by an arch thrown across 

 the pit, or on flag-stones supported on piers, or by iron rafters. The water 

 might be heated either by the perpetual burning of jets of gas immersed in 

 it, or communicating with it by small Gordon, or spiral-tubed kettles, outside 

 the pit; or by a boiler on the common circulating principle (p. 186.); or 

 by steam from a boiler placed at any distance, somewhat in Earl Powis's 

 manner, (p. 576.) If pits might be heated in this way from below, hot- 

 houses of any size might be heated from stone or iron cisterns of water, 

 not occupying greater space than the present smoke flues, and, certainly, 

 nothing could be easier than to substitute water for tan in growing pine- 

 apples. 



One of the cheapest modes of heating a Hot-house by Hot Water /at least 

 so it appears to us in the present state of our knowledge on this subject, 

 would be to employ earthen pipes 

 (p. 375.\ slate cisterns, formed in 

 Mr. Atkinson's manner (Gard. Mag., 

 vol. ii. p. 451.), and a tin or copper 

 spiral kettle of 9 or 10 in. in diameter, 

 and 20 or 24 in. high. This kettle 

 {Jig. 129.) should be connected with 

 the earthen pipes (a a) in the hot- 

 house by two small pipes (b b) carried 

 across the wall of the house, from the 

 top and bottom of the spiral kettle (c). 

 Instead of a jet of gas (d), or when the 

 gas could not be obtained, or in addi- 

 tion to the gas in very cold weather, 

 a common lamp, with a floating tin 

 burner, or any other common lamp, 

 might be used as a substitute, or to 

 increase the heat. 



If water coidd be heated by the con- 

 centration of the sun's rays, and we 

 see no difficulty in the thing but the expense, it would be an easy matter, 

 not only to heat hot-houses, but to raise the temperature of an entire gar- 

 den, or even of an entire country. Sink wells or cisterns, at regular dis- 

 tances, all over a garden or country, and place over each a concentrating 

 apparatus (p. 101.), so contrived as to operate upon a ball. ( Jig. 150. a) 

 llus ball being connected with a pipe (b), the change of temperature of 

 the water in the ball would cause the water to ascend in successive portions, 



129 



