GLASS STRUCTURES 115 



Unbleached heavy cotton cloth may be used for this pur- 

 pose, and the material for dressing it should be made of 

 three pints pale linseed oil, one ounce acetate of lead, and 

 four ounces white resin. Grind the acetate in a little oil, and 

 then add the resin and the rest of the oil. Melt in an iron 

 kettle over a gentle fire until well mixed, and apply warm 

 to the cloth. When paper is used it should be what is 

 known as manila wrapping paper. Paste this firmly and 

 tightly on the frame with fresh flour paste. Dry in a warm 

 place. Then wipe the whole of the paper with a damp 

 sponge to cause it to stretch evenly. Dry it again, and 

 apply boiled linseed oil to both sides of it, and dry in a warm 

 place. Use linseed oil that is free from cotton-seed oil. 



Shading the Glass. In the hot weather of late spring 

 or summer the sunlight is too warm for many plants in the 

 greenhouse, and it is customary to shade them. The 

 amount of shade necessary will depend somewhat on 

 circumstances. This shade may consist of lath screens 

 laid on the roof, but more commonly it is given by sprink- 

 ling the glass on the outside with a wash made of white 

 lead and gasoline, put on with a spray pump or syringe. 

 This is easily and cheaply done. It will generally come off 

 by autumn or may be rubbed off with a coarse rag or brush. 

 Whitewash is sometimes used for this purpose but it is too 

 easily washed off by heavy rains to be desirable. 



SOME THINGS TO REMEMBER IN CONNECTION WITH 

 BUILDING GLASS HOUSES FOR PLANTS 



(1) All joints should be made tight and so far as 

 possible so placed that water will not lodge in them. 



(2) There should be just as much room in the beds 

 and as little in the paths as possible. 



