258 Count Rumford's Experiments to determine 
reduced to such a size as was necessary, in order to their being 
pulled asunder in my machine for measuring the strength of 
bodies. In t is machine the body to be pulled asunder is held 
fast by two strong vices, the one fastened to the floor, and the 
other suspended to the short arm of a Roman balance, or com- 
mon steel-yard ; and in order that the bodies so suspended may 
not be injured by the jaws of the vices, so as to be weakened 
and to vitiate the experiments, they are not made cylindrical, 
but they are made larger at their two ends where they are held 
by the vices, and from thence their diameters were gradually 
diminished towards the middle of their lengths, where their 
measures were taken, and where they never failed to break. 
As I had found by the results of many experiments which I 
had before made upon the strength of the various metals, that 
iron, as well as all other metals, is rendered much stronger by 
hammering, I caused those pieces of the barrel which were 
prepared for these experiments to be separated from the solid 
block of metal, and reduced to their proper sizes, by sawing, 
filing, and turning, and without ever receiving a single blow 
of a hammer; so that there is every reason to believe that the 
strength of the iron, as determined by the experiments, may 
safely be depended on. The results of the experiments were 
as follows : 
