286 HerscheWs Telescope . 
Description of HerscheWs Forty-foot Reflecting Telescope , , 
Accompanied with an Engraving. 
THE Telescope is placed in a situation due north and 
south, and the plate delineates the whole apparatus as seen 
by a person placed at a convenient distance from it towards 
the south-west. F rom this view the structure is sufficient- 
ly understood ; and, with very little attention, the mode 
of pointing this immense body to any part of the heavens 
will be clearly seen. We shall treat of the chief parts in 
their order ; and first, of the tube itself. 
The tube is made of rolled or sheet iron joined toge- 
ther without rivets, by a similar seaming to that which is 
used for iron funnels for stoves ; the thickness of the sheets 
is somewhat less than a 36th part of an inch, or it may be 
found more accurately by taking a square foot of it at the 
weight of fourteen pounds. Great care was taken in so 
joining the plates of which the tube is composed together, 
that the cylindrical form should be secured, and then the 
whole was coated over three or four times with paint, in- 
side and outside, to secure it against the damp. The 
tube was formed at a short distance from its present place, 
and removed with great ease by twenty-four men, divid- 
ed into six sets ; so that two men on each side with a pole 
of five feet long in their hands, to which was affixed a piece 
of coarse cloth, seven feet long, going under the tube, 
and joined to a pole of five feet long, in the hands of two 
other men, assisted in carrying the tube. The length of 
the tube is 39 feet 4 inches, the diameter 4 feet 10 inches ; 
and, upon a moderate computation, it is supposed that a 
wooden tube for the same purpose would have exceeded 
this in weight by at least 3000 pounds. The length of 
the iron plate forming the tube, and composed of smaller 
ones 3 feet 10 inches long and 23 1-2 inches broad, is 
nearly 40 feet, and the breadth 15 feet 4 inches. 
