300 



ON THE CULTURE 



a bearing on two sides only, small squares must 

 consequently be the strongest, and therefore the 

 less liable to be broken. 



In this place I must not omit taking notice of 

 the common erroneous method of putting in the 

 squares of glass, which is to let them lap over each 

 other at least an inch, and in some hot-houses an 

 inch and a quarter, whereas S-8thsof an inch is found 

 quite sufficient to keep out the rain that falls on 

 the house, which will not only make a saving in 

 glass, but is better in other respects ; for the ca- 

 vity between the squares soon gets filled with dirt ; 

 and so broad a space between each square being 

 darkened, contributes to give the house a gloomy 

 appearance. Besides, the water that lodges be- 

 tween the squares in the winter is apt to freeze, in 

 which case it expands, and thereby frequently 

 causes the squares to break. 



As glass is now become the principal object, in 

 point of expense, in the building of a hot-house, 

 I flatter myself that what I have advanced on this 

 head will not be esteemed an unnecessary digres- 

 sion. 



Many small hot-houses have for their covering 

 a large sheet of canvass, which, by the help of a 

 roller and pullies, is moved up and down with 

 great ease. This is an expeditious method of 

 covering, and may be of great use on the approach 

 of a large hail-storm, though instances of damage 

 done this way rarely occur. 



But where hot-houses are large, this mode of 



