GLASS STRUCTURES 117 



(11) In the framing of greenhouses, for instance, for 

 purlins and posts gas pipe can be used to good advantage. 

 It is cheap and durable. 



(12) All joints should be painted before being put 

 together; all wood and iron work should be kept well 

 painted. 



(13) If putty is used in glazing the glass it should be 

 bedded in it and nailed in, in this way: paint the sash bars, 

 and then run a thin coat of putty along them ; bed the glass 

 in it, commencing at the bottom of the sash and lapping 

 the glass one-fourth of an inch, on the same plan that 

 shingles are laid on a roof. Fasten the glass with round 

 three-quarter inch brads, using four to each glass ; put more 

 liquid putty along the glass next to the sash bars and 

 smooth it off with a knife even with the glass. 



(14) Liquid putty is made by mixing one-third boiled 

 linseed oil, one- third white lead, and one- third common 

 putty. If too thick, as may be the case in cold weather, 

 add a little turpentine or benzine. It may be applied with 

 a brush, but the best way is to put it on with a bulb bought 

 for the purpose ; or a bulb may be made with leather, having 

 a large quill through which to squeeze the putty. In the 

 latter case there must be a hole in the side or end by which 

 the bulb is filled and which may be drawn together by a 

 string. 



(15) Perhaps the most popular way of setting glass in 

 greenhouses at present is by using square glass and butting 

 the ends together. To do this to best advantage, no nails 

 or putty are used and a special wooden cap is put on the 

 sash bar which holds the glass in place. If desired to have 

 the glass tight, the abutting edges may be just touched 

 with white lead before being put together. This makes a 

 very satisfactory roof. 



