GLASS AND GLAZING. 39 
corner (aa, 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 Bin Fig. 27. Itis 
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 Pity sr 
snaps the corners of the panes. A lap of a quarter 9% $@5%-4ar. 
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 20x 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 
“gz 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 14x 
25. Wall, gutter, plates, rafters, . po 4x18 
and sash-bars. inches as about the best size 
