“It is found during the breaking of these wires that the wire becomes alternately more yielding and less yielding to stress applied. Thus from weights applied gradually between 28 lbs. and 31 lbs. or 32 lbs., there is very little yielding, and very little elongation of the wire. For equal additions of weight between 33 lbs. and about 37 lbs. the elongation is very great. After 37 lbs. have been put on, the wire seems to get stiff again, till a weight of about 40 lbs. has been applied. Then there is a rapid running down till 45 lbs. has been reached. The wire then becomes stiff again, and often remains so till it breaks. It is evident that this subject requires careful investigation.”

TABLES SHOWING THE BREAKING OF
SOFT IRON WIRES AT DIFFERENT SPEEDS.

I.—Wire Quickly Broken.
Rate of adding weight.Breaking
weight in
pounds.		Per cent. of
elongation on
original
length.
Dark Wire.[29]
01⁄4 lb. per minute45 25.4
1„5 minutes451⁄425.9
„5„451⁄424.9
„4„441⁄424.58
„3„441⁄424.88
„3„451⁄429.58
„5„441⁄427.78
Bright Wire.[29]
1 lb. per 5 minutes441⁄428.5
„5„441⁄427.0
„4„441⁄427.1

[29] The wire used was all of the same quality and gauge, but the “dark” and “bright” wire had gone through slightly different processes for the purpose of annealing.

II.—Wire Slowly Broken.
Weight added and
number of
experiment.		Breaking
weight in
pounds.		Per cent. of
elongation on
original length.
1. 1 lb. per day48 7.58
2. „„46 8.13
3. „„47 7.05
4. „„47 6.51
5. „„47 8.62
6. „„47 5.17
7. „„46 5.50
8. „„47 6.92 bright wire
1. 3⁄4 lb. per day49 8.50
2. „„481⁄48.81
3. „„Broken by accident.
4. „„46 7.55
5. „„46 6.41
6. „„451⁄26.62
1. 1⁄2 lb. per day48 8.26
2. „„50 8.42
3. „„49 7.18
4. „„47 4.79} bright wires
5. „„461⁄26.00

The American Standard diameters of solid drawn or seamless brass and copper tube are as in the following table.

Outside
diameter.		Thickness
Stubs’s
wire-gauge.		Weight per
running foot.
Brass tubes.		Weight per
running foot.
Copper tubes.
5⁄818 3⁄8 3⁄8
3⁄417 1⁄2 1⁄2
13⁄1617 9⁄16 9⁄16
7⁄817 5⁄8 5⁄8
15⁄1616 11⁄16 11⁄16
1 16 3⁄4 3⁄4
11⁄816 7⁄8 7⁄8
11⁄412 and 1411⁄411⁄4
13⁄812„1413⁄813⁄8
11⁄212„1411⁄216⁄10
15⁄812„1415⁄817⁄10
13⁄412„1413⁄418⁄10
113⁄1612„14113⁄1619⁄10
17⁄812„1417⁄8115⁄16
115⁄1612„142 21⁄10
2 12„1421⁄821⁄4
21⁄812„1421⁄423⁄8
21⁄412„1423⁄821⁄3
23⁄812„1421⁄222⁄3
21⁄211„1323⁄43
25⁄811„133 31⁄8
23⁄411„1331⁄831⁄4
27⁄811„1331⁄433⁄8
3 11„1333⁄831⁄2
31⁄811„1331⁄233⁄4
31⁄411„1337⁄841⁄8
33⁄811„1341⁄841⁄4
31⁄211„1341⁄443⁄8
4 11„135 51⁄4
41⁄411„136 61⁄2
5 10„127 8
6 10„129 10