Length in feet.

Breadth in inches.

Thickness in inches.

Deflection in inches.

Weight producing the deflection in lbs.

Duration of the experiments in hours.

Weight that broke the piece in lbs.

2.125

2.126

2.126

.0787

7,856

4

15,631

.03937

13,525

6

21,296

.1181

14,119

18

19,993

.03937

11,750

8

21,060

4.25

2.126

2.126

.0787

6,298

21

11,844

.1574

6,298

27

12,225

.1574

6,298

..

13,565

.1574

6,298

6

12,458

6.375

2.126

2.126

.1574

3,277

6

7,244

.1574

2,860

..

7,484

.2361

2,750

5

8,492

.1574

2,750

..

7,878

2.125

3.18

3.18

.0787

34,599

27

50,958

.03937

45,168

24

50,958

4.25

3.18

3.18

.1574

20,317

29

43,639

.1574

18,647

5

36,865

.19685

20,578

9

36,205

.27559

21,819

17

28,182

6.375

318

3.18

.1574

9,121

7

26,939

.19685

9,713

19

28,987

.0787

11,000

4

23,929

.2361

10,142

18

33,048

.1574

12,746

6

36,902

2.125

4.25

4.25

.0787

61,883

11

95,262

.03937

56,691

8

66,112

.03937

56,693

23

105,826

.0787

67,467

28

94,476

.03937

57,780

30

88,442

4.25

4.25

4.25

.03937

63,066

8

100,755

.0787

29,695

5

85,998

.0787

50,525

19

73,238

.03937

45,201

19

96.368

6.375

4.25

4.25

.1574

21,586

7

64,090

.2361

17,331

5

59,373

.1574

18,517

22

54,062

.2361

27,599

22

65,608

* Gauthey's . Construction des Pouts,' torn, ii., p. 48.

139. Table XVII. - Experiments On The Resistance Of Oak When Pressed In The Direction Of Its Length. (Girard.*)

Specific gravity.

Length in feet.

Breadth in inches.

Thickness in inches.

Deflection in inches.

Weight producing the deflection in lbs.

Duration of the experiments in hours.

Weight that broke the piece in pounds, or

Remarks.

1

1.038

8.52

6.22

5.06

0.268

38,105

0.83

Recovered its first form.

3

1.010

8.52

6.22

4.00

0.09

26,381

0.83

Retained a slight flexure.

4

1.000

8.52

5.24

3.9

0.445

26,384

6.66

Idem.

5

.923

8.52

5.15

4.17

0.665

26,392

6.66

50,448

7

.973

7.46

6.22

5.06

Not sensible

138,098

0.83

. .

. .

...

...

. .

0.157

50,454

2.08

Recovered its first form.

8

.972

7.46

613

4.09

0.244

38,104

12.08

72,865

9

.925

7.46

6.22

4.00

0.267

38,106

12.08

62,977

10

1.038

7.46

4.97

4.00

0.312

26,397

10.00

Retained a slight flexure.

11

1.102

6.39

6.13

5.24

0.177

38,107

7.08

Idem.

13

.987

6.39

6.22

4.00

0.177

38,106

2.08

Recovered its first form.

15

1.032

6.39

5.24

4.17

0.22

38,048

10.00

Idem.

17

.920

7.46

6.22

4.25

0114

26,396

10.00

Idem.

19

1.038

8.52

6.22

5.06

0.177

26,392

10.00

20

.914

8.52

737

6.22

0.09

26,394

10.00

Recovered its first form.

21

.842

8.52

7.46

6.22

0.09

26,396

10.00

The numbers in the first column correspond with those of the experiments selected from M. Girard's work. The pillars rested upon a flat surface at the bottom, but turned.with a joint at the top, or were movable there in the direction of the length of the lever. Many of his experiments were made with defective specimens, which are not included, because such pieces should not be employed where they are exposed to much strain. By description and plates representing the most defective specimens, he has rendered it easy to ascertain the cause of many of the irregularities in his experiments. The least deflection only, with the weight that produced it, is given for each piece in the above Table; several other deflections were observed, but the first is the only one that is of use for the purpose of determining the strength of posts or columns. Most of the specimens bent in the direction of the diagonal, consequently they were curved both in the direction of the breadth and thickness. The deflection given above is that in the direction of the thickness, except in one case, which is Experiment 19; where the force cannot have been applied exactly in the direction of the axis. Some of the pieces were broken; in which case the weight that broke them is given. It is to be observed that the weight which broke the specimen, both in Girard's and Lamande's experiments, was about twice that which produced the first deflection. But this is to be attributed more to the method of measurement than to any absolute law, as it has not been found to hold good in the more recent experiments of Hodgkinson and others.

* 'Traite' Analytique de la Resistance des Solides,' Table I.

M. Girard has not described the state of the wood when his trials were made, but it appears from a remark he makes on the 8th experiment, that it had been cut about fifteen months;* consequently it would not be very dry, as might be inferred from the weight of the cube foot given in the third column

* 'Traite Analytique de la Resistance des Solides,' Art. 235.