36 The Colorado Experiment Station. 
5, 6 and 7, showing photographs of silo building. The exact ar¬ 
rangement is shown in drawing No. 1. 
A center 2x4 is first set a few inches in the ground and made 
plumb by temporary braces. Quarter posts (2x4) are then set at 
right angles to this center post about eight inches from the silo wall. 
These are held perpendicular to the silo wall by overhead cross arms 
(2x4), joining them to the center post, and they are prevented from 
leaning by side braces. These four cross arms are used for attach¬ 
ing the pulleys that raise both the inside and the outside forms and 
they should extend a few inches over the outside of the silo wall. 
Pulleys are shown hanging to these cross arms in the cuts 6 and 7. 
In silos fourteen feet in diameter or smaller, one 2x4 is set be¬ 
tween each quarter post, making eight outside scaffolding posts in, 
all around the center post, each one being set plumb and 8 inches 
from the silo wall. Each of these outside posts are joined to the 
center post by overhead cross-arms just as the quarter posts are. 
They will not be required to support weight and i-inch material may 
be used. Short boards should join the outside posts together as 
shown in cut 6. 
In silos over fourteen feet in diameter, two posts are set be¬ 
tween each of the quarter posts, making a total of twelve around 
the center post. After the scaffolding has been cross-braced so that 
it cannot twist under the weight of the forms, the forms may then 
be raised. 
Raising the Inside Forms .—The first step in raising the inside 
form is to draw it in, by using the adjusting bolts, so'that the sheet 
iron will be free from the concrete wall at all places. The ropes 
from the pulleys hanging from the quarter arms may then be at¬ 
tached to short boards nailed across two studs of the inside form. 
One man should manipulate each pulley rope from inside the silo. 
