and walk sunk below the level, the back wall of which was built of old floor-boards placed double, and filled in between with sawdust.
A number of minor improvements have been adopted of late years in the construction of plant houses, the effect of which has been to cheapen them considerably, without impairing, and in some instances actually improving, their efficiency. We say nothing now of patented ventilators and such like, for it occurs to us to mention, first of all, that heavy rafters and sliding lights have become almost obsolete. It is found that side ventilators are in many instances sufficient; but where roof ventilation is required in addition it may be obtained in a much cheaper and more simple way than by the adoption of sliding sashes. Separate squares of glass may be hung on hinges, or narrow-hinged lights may be inserted at intervals. The disuse of heavy rafters, in consequence of their being no longer required to carry sliding lights, allows of the use, throughout, of light sash-bars, carrying larger glass than was ever used for the purpose until within the past few years. Thus a more complete flood of light is obtained than was possible in the old-fashioned houses, while the ventilation is more perfect and far less cumbrous. As for the glass, it should be good English, weighing twenty-one ounces to the square foot. The low-priced Belgian glass is quite unfit for a plant house, however well it may be adapted for sheds and workshops; its numerous specks and bubbles act as burning glasses on the leaves beneath them, and the result is brown spots, holes, and other disfigurements.
There will still arise, perhaps, in the mind of the amateur a number of questions as to the particulars of the construction of the house required. The proper angle of the roof may be one of them, and that is by no means a matter of trifling import. For all general purposes the flatter the roof the better, because it will conduce to the short healthy growth of the plants, if they are placed as near the glass as possible; but there are two serious objections to the adoption of a low angle. It incurs a liability to drip, and it provides a playground for cats in a district where those interesting quadrupeds abound. We once suffered in a frightful manner through the breaking of a pane of glass on a low-roofed house when a party of cats were holding an out-door nocturnal demonstration upon it. They fell in and went mad with fright, and committed such
