125. On this kind of strength the experiments are most numerous, and some of the most important are collected in the following Table: -

* This was first demonstrated by M. Parent in the ' Memoires de l'Acadcmie,' Paris, for 1708.

Table XIV. - Experiments On The Strength Of Woods

Kind of Wood.

Specific gravity.

Length in feet.

Breadth in inches.

Depth in inches.

Defiec.; tion at the time of fracture in inches.

Weight that broke the piece in lbs.

Values of the constant c.

Authorities.

Oak, English, young tree.....................

.863

2

1

1

1.87

482

964

Tredgold.

Oak, English, old ship timber.....................

.872

2.5

1

1

1.5

264

660

"

Oak, English, from old tree..............................

.625

2

1

1

1.38

218

436

"

Oak, English, medium quality......

.748

2.5

1

1

..

284.

710

Ebbels.

Cak, English, green

.763

2.5

1

1

...

219

547

Tredgold.

Oak, from Riga ............

.688

2

1

1

1.25

357

714

"

" green .. ..

1.063

11.75

8.5

8.5

3.2

25812

595

Buffon.

" Canada, mean oft four experiments ..

.802

4.0

3

3

..

3863

572

Fincham.

Oak, Dantzic ..

.704

4

3

3

...

4450

622

"

Beech, medium quality

.690

2.5

1

1

...

271

677

Ebbels.

Alder........

.555

2.5

1

1

..

212

530

"

Plane-tree......................

.648

2.5

1

1

...

243

607

Sycamore....................

.590

2.5

1

1

...

214

535

"

Chestnut, green ........

.875

2.5

1

1

...

180

450

"

Ash, from young tree

.811

2.5

1

1

2.5

324

810

Tredgold.

" medium quality

.690

2.5

1

1

...

254

635

Ebbels.

" ...........................

.753

2.5

1

1

2.38

314

785

Tredgold.

Elm, common ..........

.544

2.5

1

1

. .

216

540

Ebbels.

" wych, green ..

.763

2.5

1

1

. .

192

480

"

Acacia, green .............

.820

2.5

1

1

...

249

622

"

Mahogany, Spanish, seasoned .. ..

.852

2.5

1

1

...

170

425

Tredgold.

Mahogany, Honduras, seasoned .. ..

.560

2.5

1

1

. .

255

637

"

Mahogany, New South Wales......

1.382

4

3

3

...

119

610

Fincham.

Walnut, green ...........

.920

2.5

1

1

..

195

487

Ebbels.

Poplar, Lombardy ..

.374

2.5

1

1

..

131

327

"

" abele...............

.511

2.5

1

1

1.5

228

570

Tredgold.

Teak........

.744

7

2

2

4.00

820

717

Barlow

" Malabar ..............

.724

4

3

3

...

4897

722

Fincham.

" Moulmein ..........

.909

4

3

3

...

3841

569

"

" Jahore .................

1.120

3

1 1/2

1 1/2

...

1213

1438

Mayne.

Willow.......................

.405

2.5

1

1

3

146

365

Tredgold.

Birch........

.720

2.5

1

1

..

207

517

Ebbels.

Cedur of Libanus, dry

.486

2.5

1

1

2.75

165

412

Tredgold

" Bermuda ............

.932

4

3

3

...

4119

610

Fincham.

" Cuba ................

.524

4

3

3

..

2727

404

"

Table XIV. - continued.

Kind of Wood

Specific gravity.

Length in feet

Breadth in inches.

Depth in inches.

Deflection at the time of fracture.

Weight that broke the piece in lbs.

Values of the constant c

Authorities.

Cedar, N. S. Wales ..

.555

4

3

3

..

3179

471

Fincham.

,, Jahore

.648

3

1 1/2

1 1/2

616

547

Mayne.

Riga fir..............

.480

2.5

1

1

1.3

212

530

Tredgold.

Dantzic fir

.708

4

3

3

. .

4124

611

Fincham.

Memel fir.............

.553

2.5

1

1

115

218

515

Tredgold

Norway fir, from Longsound .. ..

.639

2

1

1

1.125

396

792

,,

Mar Forest fir ..

.715

7

2

2

5.5

360

315

Barlow.

Scotch fir, English growth...........

.529

2.5

1

1

1.75

233

582

Tredgold.

,, ...........

.460

2.5

1

1

157

392

Ebbels.

Christiana white deal

.512

2

1

1

.937

343

686

Tredgold.

American white spruce

.465

2

1

1

1.312

285

570

,,

Spruce fir, British growth...............

.555

2.5

1

1

,,

186

465

Ebbels.

American pine, Wey muth................

.460

2

1

1

1.125

329

658

Tredgold.

Red pine, N. America

.512

4

3

3

...

3259

483

Fincham.

Yellow pine ,,

.437

4

3

3

...

2845

414

...

Pitch pine ,,

.682

4

3

3

3339

495

"

Larch, choice specimen

.640

2.5

1

1

3

253

632

Tredgold.

,, medium quality

.622

2.5

1

1

...

223

557

"

very young wood ......

.396

2.5

1

1

1.75

129

322

"

,, Hackmetack..

.708

4

3

3

...

4243

628

Fincham.

Kowrie...........

.614

4

3

3

...

3732

553

"

Saul........

.880

...

...

...

...

881

Skinner.

Water gum, N.S. Wales

1.001

1

1 3/4

1 3/4

.43

4408

823

Fowke.

Blue gum ,,

.843

1

1 3/4

1 3/4

.19

4482

838

"

Striugy bark ,,

.864

1

1 7/8

1 7/8

...

3078

467

"

Bastard box ,,

1.115

1

1 1/4

1 1/2

.23

5892

1716

"

Mora, British Guiana

.922

1

2

2

.19

9697

1212

"

Greenheart, yellow,

Guiana............

1.052

.79

2

2

. .

14528

1434

"

Cedar, white, Berbice

.771

1

2

2

.37

7163

895

"

Locust, British Guiana

.707

1

2

2

...

6171

771

"

Boxwood, Jamaica ..

.690

1

2

2

...

5511

689

,,

Lancewcod ,,

.675

1

2

2

...

7714

964

"

Cedar ,,

.576

1

2

2

..

3196

399

"

Lignum viba ,,

1.170

1

2

2

..

5069

633

"

Bullet.tree ,,

1.016

1

2

2

.30

9920

1240

"

West Indian ebony,

Jamaica.................

1.193

1

1 3/4

1 3/4

..

8185

1583

"

126, In these Tables, as in all the others, the author has endeavoured to collect experiments of such various kinds as would best show the strength of wood under different circumstances. He considers this preferable to taking mean results; and it will convey much more useful information to the reader. It will be seen that the specimens from aged trees are inferior in strength to those of mean age; and that the strength of green timber differs materially from that of seasoned or dry. Also, that the strength is greater in those specimens which are the most heavy; but the increase of strength is not exactly proportional to the increase of specific gravity.