J.2 THE AMATEUR S GREENHOUSE 



Gas-heating. — The heating of houses by means of gas is a 

 modificationof the hot-water system above described, and should, 

 as far as possible, be conducted on precisely the same principles, 

 the fuel being gas instead of wood, coal, coke, or charcoal. 

 There are several kinds of gas apparatus in use, and there is 

 now no difficulty in heating a plant house in an efficient 

 manner, provided only that the proprietor is prepared to em- 

 ploy experienced engineers and pay the extra cost of fuel, for 

 gas is the most expensive of materials employed for the pur- 

 pose of heating, though it is the cheapest for the purpose of 

 lighting. 



The principal advantage of gas-heating is that stoking is 

 dispensed with, and, if the pressure in the pipes is pretty con- 

 stant, the apparatus may be left for many hours without 

 attention, as the heat given off will be constant, and to a great 

 extent determinable beforehand. It must not be concealed, 

 however, that to manage a gas-heating apparatus requires some 

 amount of experience, and those who would succeed "must 

 habituate themselves to observation, not only of the action of 

 the apparatus, but of its influence on the temperature of the 

 house at different hours and in different states of the weather. 

 A body of flame sufficing only to keep out frost on a frosty 

 night with a clear sky might suffice to raise the temperature 

 of the house to 70° or 80° on a mild night with a cloudy sky, 

 and, as a matter of course, alternations so great and sudden 

 would seriously injure the plants the apparatus was intended 

 to preserve. Granting, then, that the adoption of a system of 

 gas-heating will not absolve the amateur from responsibility to 

 attend to its management, the nest question is, what form of 

 apparatus is the most to be desired ? 



The simplest form of gas-heating apparatus consists of a 

 ring of jets turning hlue, through wire-gauze, under a small 

 vessel tilled with water, over which is placed a vertical pipe, 

 the mouth of which expands like a hood over the whole aftair, 

 to catch and carry into the air without all the products of com- 

 bustion. This has the advantage of extreme simplicity, and 

 the disadvantage that it is slightly injurious to nearly all kinds 

 of plants, but especially so to camellias, oranges, and other 

 winter-flowering subjects. But for preserving bedding plants 

 and ferns, and other quick-growing subjects, it answers very 

 well ; for, being in use only when severe frost compels the 

 temporary employment of heat, the injury done is trifling, and 



