Forty-feet Refecting Telescope. 359 
bolts, ef as expressed in fig. 10. The poles being drawn up, 
the loops were put upon the centre pins < k, fig. 7. and keyed 
on ; while the lower ends of the poles were lifted into their 
places, on the cross foundation beam I I, fig. 3. and fitted 
upon the elliptical marks at the ends of them at 1, 2. 
Before the ladders and side braces were fixed down, a line 
with an hundred weight at the end, immersed in a tub of 
water, was hung upon the centre at 9 ; and being viewed from 
a considerable distance, was made to range with the flat side 
$ 9 of the ladder. The bottom of every end of the bracing 
poles and ladders being finally adjusted by this plumb-line, 
they were all screwed down by strap-bolts, as delineated in 
fig. 11. The top centre cross-beam was now also screwed to 
the loops on the ends of the ladders, which, as we have men- 
tioned before, see fig. 8. had been already prepared. 
The most essential part of the stand being now erected, 
we proceeded to brace and support it finally. Four small lad- 
ders, but without rounds, 22 feet 9 inches long, having been 
made, were erected to support the large ones half way. They 
consist of three half-poles each, placed at the same distance 
from one another as the large ones, and have their faces 
turned like them. These meet the former at the 10th flat 
with their upper ends ; while the lower parts of them rest 
upon the middle foundation beam in fig. 3. at 7, 8, 9, 10, 11, 
12 ; 13, 14, 15, 16, 17, 18. They are screwed both at the top 
and bottom with flat corner-irons as in fig. 12. and their situa- 
tion may be seen in fig. 1. 
In the next place four less poles were now added to support 
the ladders sideways. They stand upon the beams H H, K K, 
at 3 > 4, 5, 6 ; and are fastened against the ladders at the 10th 
3 a 2 
