260 On the Transverse Strain, 
of the fibres, and here we have done it to pre- 
vent their extension, in order that we might 
have their compression alone. 
For this purpose we took two pieces of 
iron of the same general breadth and. thick- 
ness as before, and whose form is that of 
figure 7th. 
These irons were firmly nailed or screwed 
to the piece of wood intended to be operated 
on as before, omitting the nails between B 
and C, and leaving the irons at the joint AB 
a small distance asunder, and held at that 
distance by two links A and B sliding upon 
the ends of the irons. The wood, with the 
iron under it, was then laid between two 
props, and a weight hung at its middle C to 
make the irons move as much as_ possible. 
The weight was then taken off, and the irons 
rendered very tight by means of the two links: 
This done, the irons being considered per- 
fectly firm, we nailed the part between B 
and C, and commenced the experiments. 
But before we give an account of these, it 
may be well to state that, at the point C, 
which was equidistant from the ends of the 
wood, the iron was flattened and drawn out 
to nearly double the breadth, and only half 
the thickness, so as to increase its flexibility 
without diminishing its strength. 
