[From Templeton's Workshop Companion.]

Materials of construction are liable to four different kinds of strain; viz., stretching, crushing, transverse action, and torsion or twisting: the first of which depends upon the body's tenacity alone; the second, on its resistance to compression; the third, on its tenacity and compression combined • and the fourth, on that property by which it opposes any acting force tending to change from a straight line, to that of a spiral direction, the fibres of which the body is composed.

In bodies, the powvcr of tenacity and resistance to compression, in the direction of their length, is as the cross section of their area multiplied by the results of experiments on similar bodies, as exhibited in the following tables.

Table showing the Tenacities, Resistances to Compression, and other Properties of the common Materials of Construction.

Names of Bodies.

Absolute.

Compared with Cast Iron.

Tenacity in lbs. per sq. inch.

Resistance to compression in lbs. persq. inch.

Its strength is

Its extensibility is

Its stiffness is

Ash,

14130

0.23

2.6

0.089

Beech, .

12225

8548

0.15

2.1

0.073

Brass,

17968

10304

0.435

0.9

0.49

Brick, .

275

562

Cast Iron,

13434

86397

1.000

1.0

1.000

Copper (wrought), .

33000

Elm,

9720

1033

0.21

2.9

0.073

Fir, or Pine, white,

12346

2028

0.23

24

0.1

" " Red, .

11800

5375

0.3

2.4

0.1

" " Yellow,

11835

5445

0.25

2.9

0.087

Granite (Aberdeen),

10910

Gun-metal (copper 8, and tin 1), .

35838

0.65

1.25

0.535

Malleable Iron,

56000

1.12

0.86

1.3

Larch,

12240

5568

0.136

2.3

0.0585

Lead,

1824

0.096

25

0.038

Mahogany, Honduras,

11475

8000

0 24

2.9

0.487

Marble, .

551

6060

Oak,

11880

9504

0.25

2.8

0.093

Rope (1 in. in circum.)

200

Steel,

128000

Stone, Rath, .

478

" Craieleith, ,

772

5490

" Dundee,

2661

6680

" Portland,

857

3729

Tin (cast)

47.36

0 182

0.75

0 25

Zinc ( sheet) .

9120

0 365

0 5

0.76