The Garden Under Glass

354 THE GARDEN UNDER GLASS remedy matters. The third cause can only be cured by search-ing for the pest, but usually by that time the plant is beyon recovery. Flaky.—A term applied to leaf-soil before it has become thoroughly decayed and when it possesses flakes of leaves. Flaky leaf-soil is best obtained before the leaves have been stacked a year. When the soil has to last for a considerable time, flaky leaf-soil is preferable to leaf-mould. Flow—The flowpipe in the heatingapparatusis that which is attached to the top of the boiler and which gradually rises until it reaches the extreme end of the house. At this point the air-tap or air-pipe is fixed and the water is then carried back to the boiler by means of the return pipe. Flues.—The spaces through which the smoke and heat from a greenhouse fire travel until they reach the chimney are called flues. These must be kept clear from soot if the fire is to draw up well. Especially is this the case where ordinary house coal is used. The old-fashioned idea of having flues carried right through the house for the purpose of heating was a serviceable one before the use of the hot-water system was in vogue. The practice is now well-nigh obsolete, and cannot be recom-mended, for boilers and pipes are now so cheap and so effective as to bring them within the power of everyone’s purse. . Forcing.—To bring a plant into growth by artificial heat and close and humid conditions of atmosphere before its natural time. To bring fruit to earlier maturity is also called forcing. Remarks on the subject will be found on pages 121, 146, 174, 193 and 200. Fore-right.—A fore-right shoot is one which grows out from the front of a branch instead of from the sides. As they are difficult to train in the case of a Iruit-tree trained against a wall they are usually pinched out when but a few inches long. Fumigate.—To fi.ll a house with the fumes of somc sub-stance (usually containing nicotine) for the purpose of killing