Glass-Cases are of various kinds. One is formed of glazed wooden frames, fitting together, to protect espaliers, wall-trees, or shrubs too large to be covered with a hand-glass.

Another glass-case is made for protecting a single branch. It is thus described by Mr. Maund, the author of that most useful periodical the Botanic Garden: -

"Although my experiment is not yet completed, I cannot omit mentioning to you its success. Grapes grown on open walls in the midland counties are rarely well - ripened; therefore this year I provided a small glazed frame, a sort of narrow hand-glass, of the shape shown in the annexed outline, to fix against the wall, and inclose one branch of the vine with its fruit and foliage. "The open part, which rests against the wall, is thirteen inches wide, and may be of any length required to take in the fruit. The sides are formed of single panes of glass, seven inches wide, and meet on a bar which may represent the ridge of a roof, the ends inclosed by triangular boards, and having a notch to admit the branch. This was fixed on the branch a month be- fore the vine came into flower. The consequence was, the protected branches flowered a week earlier than the exposed. The frame was not fitted closely to the wall, but in some places may have been a quarter of an inch from it. The lateral branches being shortened before it was fixed, it did not require removal even for pruning, because I adopt the long-rod mode of training, which is peculiarly adapted to my partial protection system.

The temperature within the frame is always higher than without, sometimes at midday even from 20° to 30°.

"By this simple protection I find grapes may be ripened from three weeks to a month earlier than when wholly exposed, and this saving of time will, I believe, not only secure their ripening well every year in the midland counties, but also that such advantage will be available in the north of England, where grapes never ripen on the open walls".

Fig. 56.

Lastly, there is the Wardian-case to cover plants growing in rooms, preserving to them uniform moisture and excluding dust. To prevent the dew which is occasionally deposited inside the glass, it is only necessary to open the case frequently, for a few minutes, to render the temperature within similar to that outside. They are not intended to exclude the air, and are now made very ornamental.

Fig. 57.

Fig. 58.

Fig. 59.