STRENGTH OF RAILS.

167

EXPERIMENT II.

Weight

in -cwts.

Deflexionin inches.

28

.06

56

.11

84

.2

112

.35

126

.47

28

.11

126

.47

131-5

.57

56

.115

126

.48

140

.63

154

.92

REMARKS.

On (lie weight being removed it immediatelyresumed its original form; and to ascertain if any' injury had taken place, the following experiments, were made.

When the weights were taken off, the bar again’returned to its original form; the weights were■then replaced, and the successive deflexions cor-responded with the respective weights as in the'former experiment.

When unloaded it came back to its original form.

The weights were again applied, and the respective deflections found as described ; the weightswere allowed to remain on for some time, and, onbeing removed, a permanent deflexion had taken1 place of .0035 inclies.

On the weights being again added, the deflex-lions were nearly similar to those previously ob-served. When loaded with 154 cwt. the deflexion> was found as staled ; the weights were then re-moved, and it was found that the bar had acquir-ed a permanent bend of .24 inches. The rail did' not appear otherwise injured.

EXPERIMENT III.

Rail, three feet long, merely laid upon the supports,without being fastened.

Was loaded with 112 cwt., and, on the weights beingremoved, it returned to its original form. The weightswere again laid on, and, also, an additional quantity,amounting to 127f cwts. which, when taken off, the baragain came to its original shape. It was then loadedwith 140 cwt. which, on being removed, was found tohave given a permanent deflexion of .25 inches.