374 Dr. Herschei/s Description of a 
The lowest bar is a little stouter in its dimensions, but other- 
wise exactly the same. 
The middle bar at the top is strongest about the point of 
suspension, where it is 4 inches broad, and 1 inch thick. In 
this place it is crossed by another bar, which is a segment of 
a circle, and embraces the middle one, and two other bars at 
each side. This crossing bar is 3^- inches broad, and 1 inch 
thick in the centre ; chamfered or sloped at the sides, and 
reduced in thickness towards the ends. It passes over the 
middle bar with a proper offset, and its two ends terminate 
upon the two farthest bars ; but the bars next to the middle, 
on each side, are made to pass over it. The middle bar re- 
ceives a loop, by which the telescope is suspended, the centre 
of which is 3 feet 8 inches from the mouth of the tube. The 
loop is made of iron, 4 inches broad, and 1 inch thick ; 
doubled together, and the ends of it opened again, so as to 
cross the circular bar, and to rest upon the strong middle one, 
to which it is-fastened with four large screw-bolts. These 
pass through the bar into the tube, where they are well se- 
cured with substantial nuts. The long middle bar is reduced 
gradually after the place of the loop, the ends of which ex- 
tend about 18 inches, till it comes at last to the breadth of 2^ 
inches, and thickness -§-. 
All the ten bars are secured with six screw-bolts each, 
which pass through the tube, and through iron hoops, four of 
which are of the same dimensions with those which are used 
about the point of support. The hoop which is under the sus- 
pension is 8 inches broad, and a little thicker than the rest. 
The front hoop is of a different construction : its thickness is 
