The following tables and formulae are given for the benefit of those readers who may not have at hand a special work treating of the subject. They are in all cases based upon the formulas and unit strains given in the author's Architects' and Builders* Pocket Book and a portion of the tables are copied direct:

Table I. Properties Of Timber, Stones, Iron And Steel

Weight per cubic foot in pounds.

Average.

Weight per foot,

B. M. in pounds.

Average.

Safe Tensile Strength, lbs. per square inch.

Safe Crushing

Strength in pounds per square inch.

Safe Centre Load, lbs.

for Beam 1 inch square and 1 foot long.*

Safe Shearing Strength with the - Grain, pounds per square inch.

Safe Crushing Strength across the

Grain, pounds per square inch.

Chestnut ......................

40

3.3

1,500

530

60]

..

• « • •

Hemlock ........................

30

2.5

1,200

450

55

70

200

Oak, white ......................

52

4.3

2,000

750

75

150

600

Pine, Georgia yellow.

43

3.6

2,000

1,000

100

120

500

Pine, Oregon ...................

36

3

1,800

800

90

100

400

Pine, Norway...............

36

3

1,600

700

70

90

400

Pine, white Western .

30

2 5

1,500

625

65

80

200

Redwood ....................

30

2.5

800

600

60

70

175

Spruce .......................

36

3

1,800

700

70

90

250

Whitewood ......................

35

3

1,200

500

65

. •

200

Slate .............................

174

• • • •

• • • •

40

.

Bluestone flagging...

• • •

• • ■ •

• • • •

25

. •

Granite ........................

167

• • • •

850

18

.

Limestone (Ind) ...................

158

• • • •

550

18

. .

Marble ................................

170

• • • •

550

18

• • • •

Sandstone .........................

139

■ • • •

45o

12

....

Cast iron ......................

450

2,600

13,500

222

7,000

Wrought iron ....................

480

10,000

10,000

666

7,500

12,000

Steel, medium ....................

490

12,500

13.000

888

7,500

12,000

" pins...

• • •

■ • • •

• • • ■

• •

7,500

12,000

" rivets..

• • •

• • • •

• • • •

• •

7.500

15,000

* One-eighteenth of the "fibre strain or safe "Modulus of Rupture."

† For full permanent loads, such as brick walls, etc., use only four-fifths of these values.

Table II. Strength Of Round Rods Of Iron And Steel

Diameter in inches.

Not Upset.

Upset.

Allowed strain per sq. in.*

Allowed strain per sq. in.*

10,000 lbs.

12,500 lbs.

15,000 lbs.

10,000 lbs.

12,500 lbs.

15,000 lbs.

1,256

1,570

1,884

I.963

2,453

2,944

5/8

1,963

2,453

2,944

3,068

3,835

4.600

3,000

3,750

4,500

4,418

5,520

6,627

7/8

4,200

5,25O

6,300

6,013

7,516

9,020

1

5.430

6,780

8,140

7,854

9,815

11,780

1 1/8

6,860

8,57o

10,290

9.940

12,425

14.900

1

8,850

11,060

13.270

12,270

15, 330

18,400

1 3/8

10,700

13.370

16,050

14,840

18,550

22,260

1

12,870

16,080

19,300

17,670

22,080

26,500

1 5/8

15,000

18,750

22,500

20,730

25,910

31.090

1

17,600

23,000

26,400

24,050

30,060

36,070

1 7/8

20,200

25,250

30,300

27,610

34,500

41,400

2

22,800

28,500

34.200

31,420

39,270

47,130

2 1/8

26,400

33.000

39,600

35.460

44.320

53,190

2

30,000

37,500

45,000

39,760

49,700

59.68o

2 3/8

33,500

41,870

50,250

44.300

55,370

66,450

2

37,200

46,500

55,800

49,080

61,350

73.620

2

46,400

58,000

69,800

59.390

74,230

89,080

3

54,000

67,500

81,000

70,680

88,350

106,000

3

65,000

81,250

97,500

82,950

103,690

124,400

3

75,400

94,250

113,100

96,210

120,260

144,300

3

85,600

107,000

128,400

110,450

138,060

165,600

4

99,000

123,750

148,500

125,660

157.ooo

188,490

4

113,400

141,700

170,100

141,800

177,250

212,700

4

126,000

157,500

189,000

159,000

198,750

238,500

4

141,800

177,250

212,700

177,200

221,500

265,800

5

157,600

197,000

236,400

196,300

245.370

298,400

5

175,900

219,870

263,850

216,400

270,500

324,000

5

192,600

240,750

288,900

237,500

296,800

356,000

5

212,300

265,370

318,400

259,600

324,500

389,000

6

231,000

288,750

346,500

282,700

353.300

424,000

* For first-class work and material xa.500 lbs. may be allowed for iron and 15,000 lbs. for steel. If the rods are to be welded or are made by an ordinary blacksmith, use 10,000 lbs. for iron and 12,500 lbs. for steel.