286 
PROFESSOR OSBORNE REYNOLDS AND MR. J. H. SMITH ON A 
stress measured. The mean for these three tests was 25'81 tons per square inch ; 
the yield-stress and extensions could not be conveniently measured. 
During the preliminary tests (described on p. 281), it had been noticed that the 
reversals for rupture for any given range of stress diminished as the rapidity of 
reversals increased, and the author decided to carry out a number of tests to 
investigate this point. He decided to carry out six sets of tests with the standard 
form of specimen (fig. 4). 
In each set of tests, specimens from every one of the six bars were used; the load 
supported by the specimen was kept constant and the speed varied. The load was 
changed from set to set so that there might be six tests for any given range of stress, 
each carried out at a different speed. The first test of each set was, as a rule, done 
at the highest speed at which the machine could be run. The range of stress was 
varied for the subsequent tests in the set by reducing the speed. It was decided to 
limit, in general, the experiments to tests taking not more than two million reversals 
for rupture. The results of these tests are given in Table III. 
Table III. 
Set A. 
Annealed Mild Steel. 
Oscillatory weight, 12'42 lbs. 
Diameter of Specimens, ‘245 inch to '247 inch. 
Number. 
Revolutions per 
minute. 
Maximum 
stress. 
Minimum 
stress. 
Range of 
stress. 
Reversals for 
rupture. 
1 
2380 
10-00 
S'95 
18-95 
28,090 
2 
2306 
9-43 
8-43 
17-86 
22,100 
o 
o 
2240 
9-01 
8-05 
17-06 
80,700 
4 
2191 
8-59 
7-66 
16-25 
136,000 
5 
2126 
7-99 
7-11 
15-10 
248,700 
6 
2047 
7-51 
6-67 
14-18 
416,000 
hr 
t 
1956 
6 • 81 
6-02 
12-83 
334,000 
8 
1054 
6 • 87 
6" 08 
12-95 
682,000 
9 
1909 
6-51 
5-74 
12-25 
1,138,000 
10 
1888 
6-26 
5-50 
11-76 
1,787,000 
(Not broken.) 
Unannealed Mild Steel. 
Diameter of Specimens, '24 inch to '25o inch. 
11 
2492 
11-83 
10-65 
22-48 
43,000 
12 
2438 
11-17 
10-03 
21-20 
34,100 
13 
2382 
10-54 
9-46 
20-00 
66,700 
14 
2356 
10-09 
9-02 
19-11 
59,000 
15 
2346 
9-91 
8-87 
18-78 
61,000 
16 
2238 
9-03 
8-07 
17-10 
73,800 
17 
2190 
8 - 33 
7-44 
15-77 
66,000 
18 
2122 
8-03 
7-17 
15-20 
226,500 
19 
2071 
7-34 
6 -54 
13 ■ 88 
162,700 
20 
2015 
6-72 
5-96 
12-68 
2,025,000 
(Not broken.) 
