S82 Mr Low's Descriptmi of a Machine 
are three holes ah for the reception of the strong iron 
pin, DE, upon which is made to slide the curved iron- 
bar CG. The pin is so thrust through the holes in the 
posts already mentioned, that the post C of Fig. 1. shall be 
next to the thick end of the pin E ; the post B in the 
middle at 5, within the bend of the crooked bar CG, and 
the post A next to the pin at D, which is thrust through 
the other to keep the apparatus together. The holes ahc be- 
ing of such a size as to allow a little play to the posts, these 
last may be stretched out like the legs of the common theodolite, 
in the manner represented in Fig. 1 . To the curved iron-bar 
are then attached the fixed block M, containing four or more 
pulleys, and the moveable block N, containing ihe like number 
of pulleys. Each of these blocks must be hooped with a very 
strong bar of iron, and the pulleys must be of a size to admit of 
a thick rope passing over them. To the lower block N is to be 
hooked the iron plug P, consisting of a ring, a flat part, and a 
cylinder. The cylindrical part may be 7-8ths of an inch in dia- 
meter at the point, gradually increasing to about the 16th part 
of an inch more in diameter at the neck, and being about 2 inches 
in length. The end of the rope O, in Fig. 1. passing over the 
fixed pulleys, is attached to the windlass FH, which may be 6 feet 
or more in length, and which is fixed by its axis to the posts A 
and C. At each end of this windlass is a winch T and U, for the 
purpose of saving time, by tightening the ropes previous to the 
windlass being worked. The windlass is worked in the usual 
manner, by levers, for the reception of which are mortises, as 
shown in the figure. At one end of the windlass is fixed the 
ratchet wheel VY, (the catch X being fixed to the post A,) for 
the purpose of preventing the weight from falling back when 
the moving power is withdrawn. The two posts A and C should 
be connected by a cross bar, to keep them steady in their place. 
The machine thus described is easily managed. It is placed 
over the stone to be raised, by extending the posts on each side, 
and then the windlass is attached. Of the stone to be thus rai- 
sed, however large it be, it is enough to see the smallest part ap- 
pear above the surface of the ground. At this part let a work- 
man, with a mallet, and the common steel-boring chisel of ma- 
