162 Mr Buchanan on the Strength (^Materials, 
suaded it would form an extremely convenient and accurate 
measurer of such intense strains. 
Experiments.— O n Bars of Memel fr^ sup'ported at each end^ 
and loaded in the middle. Distance between the supports 
5 Jeet. 
1. A bar 2 inches square, with 170 lb. bent half an inch, 
with 357 lb. bent 1 inch, and the pressure being removed, the 
bar rose again in the middle, and returned to a straight line, 
shewing that the strain had not been sufficient to give it any 
new set, and that it may therefore be applied to it safely for a 
short time ; witli 442 lb. the bar bent 1 J inch, but in being re- 
lieved of this pressure, it only returned to |th of an inch of a 
straight line, shewing that it had now become overloaded, and 
was beginning to give way, — with 510 lb. it bent l/o^^ inch, 
and with 595 lb. it broke. 
2. Another bar, 2 inches square, with 170 lb. bent | inch ; 
with 344, bent 1 inch, and load being removed, rose to a straight 
line; with 450 lb. bent Ig inch, and with pressure removed, 
returned to |th inch of a straight line ; with 510 broke. 
3. A bar 3 inches broad, and 2 inches deep, laid on its side, 
with 255 lb. bent § inch ; with 527 lb. bent 1 inch ; with 680 lb. 
began to crack or cripple on the under side ; with 850 lb. broke. 
4. Another bar, 3 inches by 2, but now laid on its edge, with 
357 lb. bent | inch ; with 722 lb. bent 1 inch, and on pressure 
being removed, returned to a straight line ; with 1045 lb. bent 
1 J inch, and pressure let off, rose to 3 -^ 3 ^ th inch of a straight line ; 
with 1190 lb. bent 2 inches, and broke. 
5. Bar 4 inches by 2, with 340 lb. bent | inch, with 654 lb. 
bent 1 inch ; with 1037 lb. bent 1 J inch, and broke. , 
6. Bar 2 inches by 3, with 1020 lb. broke. 
On Bars of Cast Iron. Distance between supports 32 inches. 
1. A bar 1 inch square, with 357 lb. bent | inch ; with 765 
bent I inch, and pressure being let off, returned to ^^^th of an 
inch of a straight line ; with 770 lb. broke. 
8. A bar 2 inches by 1, laid on its side, with 714 1b. bent 
ith inch ; Avith 1062 lb., bent 0.37 inches, and returned to 
inch; with 1530 lb. broke. 
These experiments prove several important particulars relative 
