54 GREENHOUSE CONSTRUCTION AND HEATING. 
the form shown in Fig. 37. A hole is drilled at a, and a 
screw put in. One of such holdfasts placed every 5ft. or 
6it. will effectually 
prevent the plate from 
shifiing, or if it does 
the wall must go too. 
If the iron is just let 
in to the plate at a, 
a neater appearance 
will be afforded. 
Another way is to 
secure the plate at 
intervals by means of 
a round iron rod 
passing through the 
FIG. 38, plate. and through a 
standard supporting the purline, with a head at one end and 
a thread and nut at the other. If iron standards are used, 
or it is not considered desirable to weaken wooden ones 
by making holes through them, an iron strap or collar may 
be passed round each, and 
tightened up, as well as 
secured to the rod, by 
means of a bolt and nut, 
passing through a hole in 
the rod. This makes a 
very sound and good job. 
If there is no purline or 
standards, the rods may 
be bent down and secured to stout posts sunk in the bed or 
floor of the house, or to the staging if there is any. 
1 
Fie. 39. 
