of Metal Rods with rounded ends. 
285 
It was found that the difference between the values on loading 
and unloading was attributable to gradual creeping, and the 
experiment was therefore tried of running the full load on 
suddenly, and then after running past it and back to it again, so 
as to exclude the friction effect of the machine, suddenly unload- 
ing. The values on loading and unloading then became equal, 
and both slightly less than before. The readings are as follows : — 
Load (lbs.) 
Reading 
Difference 
Mean 
0 
1200 
4-14 
8-71 
4-57 
4-570 
1200 
0 
8-71 
417 
4-54 
0 
1200 
4-19 
8-77 
4-58 
1200 
0 
8-79 
4-20 
4-59 
Using this value we get 
8 x 966 x 1200 x 4 
4'57 x 7r x (•.509)“ 
9,972,000 lbs. per sq. in., 
whence 
972,000 x 32-18 x 144 
168T 
16,580 ft. per sec. 
It is this value of v which is used in comparison with the 
dynamic method. 
It is just possible that, by similar treatment, the copper 
specimen might also have yielded a slightly higher value. 
