the plants soon recover from it when the growing days of spring return. A merely common gas-flame is, however, not to be tolerated in a plant house, except in the way of a few small jets to afford light, and these are always allowable, the minuteness of the combustion exercising so minute an influence as to be practically of no consequence whatever.
The best form of apparatus is that which consists of boiler and circulating pipes, and it is always advisable to place the boiler in a separate apartment, even if a portion of the plant house has to be screened off by means of glass for the purpose. However careful we may be to provide ready exit for the products of combustion, a gas-flame of sufficient power to afford the amount of heat required must prove prejudicial to plants when in close proximity to them. It commonly happens, however, that the house best adapted for gas-heating occupies a position adjacent to an entrance-hall or some other 
apartment, in which the boiler can be placed for both use and ornament. It must not be forgotten either that a boiler adapted for the purpose can be placed, as well beneath as beside the conservatory to be heated, for the pipes in which the water circulates may range vertically or horizontally at discretion, provided the work is well done. In many cases a gas apparatus might be adapted to heat a bath-room and a plant house, and afford the additional convenience of management within doors, without any occasion for exposure to the night air in the winter season.
A simple and effective form of gas-stove is that known as Trotman’s. which is manufactured by Mr. Trotman, of Isleworth. The stove stands about thirty inches to the top of the lid; the diameter nine inches. The centre to within six inches
