54

COMPRESSION.

Modulus offrac-ure or height of

Material.

Weight>f a cubicfoot inounces.

bs. avoirdupoisto crush cubesof one and ahalf inch.

i column inchand half squaren section of thematerial equal inweight to thecrushing weight.

Feet.

Chalk - -

2500

1127

461

Brick of a pale red colour

2085

1265

621

Red brick, mean of two trials -Yellow face baked Hammersmith 1

2168

1817

2254

858

paviers, 3 times - -J

1064

Burnt ditto, mean of two trials

3243

1532

Stourbridge or fire brick

3864

1825

Derby grit, aredfriable sand-stone

2316

7070

3126

Ditto, from another quarry

2428

9776

4123

Killaly white freestone, not stra- 1tided - - - j

2423

10264

4338

Portland* - - -

2428

10284

4337

Craig Leith, white freestone

2452

12346

5156

Yorkshire paving, with the strata

2507

12856

5251

Ditto ditto, against the strata

2507

12856

5251

White statuary marble, not veined

2760

13632

5058

Bramly Fall sand-stone, near \Leeds, with strata - J

Ditto, against the strata -Cornish granite

Dundee sand stone or Brescia , 1

2506

2506

2662

2530

13632

13632

14302

14918

5571

5571

5502

6038

two kinds - - /

Craig Leith, with the strata

2452

15560

6498

Devonshire red marble, variegated

16712

6623

Compact limestone

2584

17354

6878

Peterhead granite, hard close 1grained - - - /

18636

7386

Black compact limestone, Limerick

2598

19924

7607

Purbeck - -

2599

20610

8120

Black Brabant marble -

2697

20742

7876

Very hard freestone - -

2528

21254

8610

White Italian veined marble f -

2726

21783

8183

Aberdeen granite, blue kind

2625

24556

9581

* To crush a two-inch cube of Portland required 14918 lbs.f Rondelet’s experiments shew statuary marble to be stronger thanveined marble in the ratio of 8176 to 7455.