GLASS AND GLAZING. 



39 



corner (a a, Fig. 27, page 41 ), and are held firmly to the bar 

 by glaziers' points (ee, Fig 27). The panes are 

 seen edgwise. in cross-section, at B in Fig. 27. It is 

 important, to avoid breakage, that no nail or point 

 be placed on the middle of the pane. No putty 

 is placed over the glass, for, in the nearly hori- 

 zontal or inclined position in which the panes lie, 

 the water would collect underneath any such putty 

 and would crack it off by freezing. If the panes 

 are well bedded, and if the bars and the edges of 

 the glass are given a coat of paint, the job will 

 be perfectly tight. It is imperative that the lap on 

 the panes should be very short. A long lap col- 

 lects dirt and thereby obstructs the light, and it 

 also holds so much water that the freezing of it Yer.and raster 

 snaps the corners of the panes. A lap of a quarter and *"*-* 

 of an inch, or at most of three-eighths inch, is ample. In this 

 narrow lap the water of condensation collects and makes a 

 warm joint. 



There has been a tendency in recent years towards the 

 use of very large glass. Panes as large as 20 x 36 inches 

 have been used. These seem to be too wide for economy, 

 and they impose severe strains upon the sash-bars, and 



weaken the 

 rigidity of the 

 house. The 

 glass bears too 

 great a pro- 

 portion to the 

 structural 



frame of the roof. It is 

 doubtful if it is wise to use 

 glass above 14 or 16 inches 

 wide, and, through inquiry 

 and experience, the writer 



has now settled upon 14 x 18 

 35. Wall, gutter, plates, rafters, . , , , , . 



and sash-fart. inches as about the best size 



