THE PRACTICAL GARDENER. 



by any shaking of the sash ; nor yet too narrow, which would 

 admit the water to enter into the house ; and that it be well 

 bedded in good old putty, so as to lie solid, and therefore sus- 

 tain a greater pressure. A great fault in the glazing of hot- 

 houses is allowing too much overlap, that is, one pane project- 

 ing over the other too much ; and it is difficult to get trades- 

 men to attend to this very important point. The broader the 

 lap is, the more liable is the glass to be broken, as it contains 

 a greater body of water, conveyed into it by capillary attrac- 

 tion ; and when such water becomes frozen, the expansion is 

 so great, as not only to break the glass, but it soon fills up 

 with earthy matter, forming an opaque space, which are both 

 injurious, by excluding a large portion of light, and also dis- 

 agreeable to the sight. The accidental filling up of such 

 spaces with filth, probably first gave the idea of filling the laps 

 up with putty of various colors, principally black, and was an 

 important improvement in hot-house glazing; soon after fol- 

 lowed the adoption of narrower laps, either puttied or left 

 open. 



Laps of less than a quarter of an inch, in either rectanguJar 

 or curvilinear formed panes, may be puttied without having a 

 bad effect, and will materially aid in preventing the glass from 

 being broken. The expansion of water by frost, which lodges 

 between the laps, breaks more glass than any other natural 

 cause whatever. This mode of closing the lap, either for the 

 exclusion of cold or wet, is more durable, and less troublesome 

 in repairing, than any other. The smaller the laps are, so 

 that they cover the joint perfectly, the neater will they look, 

 and the less liable will they be to be broken. 



Putty of the best quality should only be used for hot-house 

 glazing, and that called soft 'puity, being formed of well 

 wrought paste of flour of whitening and raw linseed oil, is 

 the best and most durable, because it forms an oleaginous coat 

 on the surface, and requires longer time to dry. Other sorts 

 have been used and recommended, but the difficulty of getting 

 it out in repairing is so difficult that it is found advisable to 

 use only the soft piittij. Of the various forms of glazing, 

 may be mentioned the following: the rectangular; the frag- 



