for liaising Stones. ' 'MS 
sons, make a small circular hole, about two inches deep, and as 
perpendicular as possible. This chisel should be of such a size 
as to make the hole about a sixteenth part of an inch less in 
diameter than the plug itself, so that a stroke or two of a ham- 
mer may be necessary to drive the iron home. When the lat- 
ter is thus driven an inch, more or less, into the stone, it is at- 
tached to the block, and the ropes are tightened by turning the 
winch. Nothing more is now requisite, than to set as many 
persons as may be required to work the windlass ; and, strange 
as it will seem, with no other fastening than this simple plug, 
the heaviest mass will be torn up through every opposing ob- 
stacle, and lifted into the air. 
I could well pardon incredulity in any one who was, for the 
first time, told of such an effect produced by such means. When 
the fact was mentioned to some distinguished men of science in 
this country, they remained incredulous, and were only convin- 
ced by seeing the engine itself at work ; and I have not heard 
that any of these gentlemen have explained the principle of ac- 
tion of the machine. I understand that the general opinion, 
on first witnessing the experiment, was, that the iron-plug, when 
driven into the stone, was not precisely in the direction of the 
moving power, and that the mass was raised and suspended in 
the manner shown by the plugs A and B, in Fig. 2. This ex- 
planation, I apprehend, cannot be admitted ; and it is to the 
elasticity of the stone, and not to the direction of the moving 
force, that we must attribute the effect produced. The iron is 
forced down by a stroke, and retained in its position by the elas- 
tic power of the stone, in the same manner as a similar pin 
would be held by a block of wood, into which it was forced by 
the same means, with this difference, that the elastic power ex- 
erted upon the iron by the harder stones, would be incompa- 
rably greater than that exerted by the wood. That this is the 
true explanation of the phenomenon, is confirmed by the facts 
of the experiment itself : For, It is found, that the moving 
power may be made to act in the direction of the hole with 
the utmost precision, without varying in the least the result ; 
2d, That when the mass is raised from the earth, it may be mo- 
ved into any position without being detached ; and, 3d, That, 
while hardly any constant force will pull out the plug, a smart 
