GLAZING. 11 



other purpose it is not necessary, for, by frequent applica- 

 tions of the syringe, and by pouring water upon the tables 

 and floors, a sufficiently moist atmosphere can be maintained, 

 without risk of any kind. 



GLAZING. 



VEBY few words upon this subject will suffice. 

 The kind of glass we use is 21-oz. English sheet 

 glass, and we find it the most serviceable, as it is 

 not easily broken, either by cleaning or by any ordinary usage. 

 Nothing is gained by having the squares very small, but 

 at the same time we dislike very large ones, as they are 

 extremely liable to be broken in frosty weather. If the 

 panes are about two feet six inches in length, and nine 

 inches in breadth, they will have a very good appearance, 

 the same width being used for the upright side sashes as 

 for those on the roof. Care should be taken in selecting the 

 glass free from blisters, as these are very destructive to the 

 plants, causing burns or scalds on the leaves. 



VENTILATION. 



j|OOD ventilation is of the highest importance, for 

 a constant renewal of air in plant houses is 

 essential to the well-being of the occupants ; 

 indeed, where the necessary temperature can be maintained, 

 we would never quite close the houses, day or night, except 

 in severe weather. Let us, however, be properly understood 

 upon this subject. By good ventilation, we mean always to 

 avoid draughts and currents of cold air, these being most 



