268 GEOLOGICAL SURVEY 
Fig. A. 
Fig, A, is the side view in perspective. 
i, i. The base, consisting of 3 pieces of scantling, each 12 feet long, and 11 inches by 5, notched 
on to each other, about 6 inches from the end, so as to be flush on top, forming an equilateral triangle. 
e. The principal post, 8 feet, 8 by 6 inches, secured to the base, and braced by the braces f. Near 
the top of this post 2 iron sheeves or pulleys are placed, one on each side, and secured by pieces 
spiked over them. 'The chains pass over these pulleys. 
f. 2 braces 11 feet long, 4 inches by 6. 
h, h. Two uprights, in which the gudgeons of the wheel turn; they are bolted to the base, and 
connected at top by the piece g, 10 feet, 6 inches long, 43 by 6 inches, which also serves as a hand 
rail for the men to steady by when working on the wheel. These uprights are further secured by 
cross pieces connected with the braces, and bearing in front and rear of the wheel two steps, on 
which the men stand as they go on or off the wheel. 
w. The wheel, 4 feet in diameter, the steps 3} feet long 8 inches wide, made of 14 inch plank. 
The ends of the wheels are formed of two thicknesses of inch plank placed crosswise, the inside 
being grooved to receive the steps, which are placed about 8 inches apart. The axle of the wheel 
is 10 feet 6 inches long and 8 inches in diameter; the portion around which the chain winds is en- 
larged, so as to suit the force employed on the wheel, or the weight to be raised, by nailing on strips 
of plank, over which a few turns of old rope may be placed, to prevent the slipping of the chain. 
To prevent confusion, only one crane (or arm) is represented in this figure. 
The crane post, represented as turning on two iron pivots in pieces s s, one bolted to the principal 
post e, and the other spiked to the base. 'The crane post is 6 inches square. 
a. The crane jib, 7 feet 6 inches long, 6 by 7 inches. 
b. The strut to the jib, 8 feet 6 inches long, 4 by 6 inches. Near the extremity of the jib an iron 
sheeve is fixed, over which the chain passes. 
c. Is a three quarter inch rod of iron, secured to a by means of a staple, and having a hook at the 
other extremity, which drops into a staple at i. This rod serves the double purpose ofa stay and a 
guide, by which (when unhooked) the arm is drawn to one side, for the purpose of landing the box. 
When fixed, as represented in the drawing, it serves to retain the crane in its proper position. When 
the box is raised, the rod is unhooked, and by means of it the box is landed. 
