A bridge across the Bosphorus, with a span of 2,550 feet, to unite European and Asiatic Turkey.

A bridge across the English Channel, about 24 or 25 miles in length.

LEAD MEMORANDA.

For roofs and gutters use 7-pound lead.

For ships and ridges use 6-pound lead.

For flashings use 4-pound lead.

Gutters should have a fall of at least one inch in 10 feet.

No sheet of lead should be laid in greater length than ten or twelve feet without a drip to allow of expansion.

A pig of lead is about three feet long, and weighs from a hundred-weight and a fourth to a hundred-weight and a half.

Spanish pigs are about a hundred-weight.

Joints to lead pipes require a pound of solder for every inch in diameter.

WEIGHT OF WROUGHT-IRON AND STEEL.

General Rules for determining the Weight of any Piece of Wrought-Iron.

Thus it appears that the weight of any piece of wrought-iron in pounds per yard is equal to ten times its area in square inches.

EXAMPLE. The area of a bar 4 inches x 1 inch

inches, and its weight is 40 lbs. per yard.

= 4 square

For round iron, the weight per foot may be found by taking the diameter in quarter-inches, squaring it, and dividing by 6.

EXAMPLE.-What is the weight of 2-inch round iron ? 2 inches 8 quarter-inches. 82 = 64.

EXAMPLE.

6103 lbs. per foot of 2-inch round.

-What is the weight of 3-inch round iron?
3-inch 3 quarter-inches. 3o 9.

1 lbs. per foot of 3-inch round.

The above rules are very convenient, and enable mental calculations of weight to be quickly obtained with accuracy.

Steel. To find the weight of a steel bar, first determine what the weight would be if of wrought-iron, and then add 2 per cent.

WEIGHT PER FOOT OF FLAT, SQUARE, AND 'ROUND

WEIGHT PER FOOT OF FLAT, SQUARE, AND ROUND WROUGHT-IRON (Continued).

WEIGHT PER FOOT OF FLAT, SQUARE, AND ROUND WROUGHT-IRON (Concluded).

WEIGHT, PER FOOT, OF FLAT IRON.

For steel add 2 per cent.

7.29 7.55 7.81 8.07

8.75 10.21 11.67 13.13 14.58 16.04 9.06 10.57 12.08 13.59 15.10 16.61 9.38 10.94 12.50 14.06 15.63 17.19 9.69 11.30 12.92 14.53 16.15 17.76

1.560 3.130 4.690 6.250 1.610 3.230 4.840 6.460 8 1.670 3.330 5.000 6.670 8.33 10.00 11.67 13.33 15.00 16.67 18.33 1.720 3.440 5.160 6.880 8.59 10.31 12.03 13.75 15.47 17.19 18.91 1.770 3.540 5.310 7.080 8.85 10.63 12.40 14.17 15.94 17.71 19.48 1.820 3.650 5.470 7.290 9.11 10.94 12.76 14.58 16.41 18.23 20.05 13.13 15.00 16.88 18.75 20.63 13.49 15.42 17.34 19.27 21.20 13.85 15.83 17.81 19.79 21.77 14.22 16.25 18.28 20.31 22.34

6666

9/1/2

93

1.88) 3.750 5.630 7.500 9.38 11.25
1.930 3.850 | 5.780 7.710 9.64 11.56
1.980 3.960 5.940 7.920 9.99 11.88
2.030 4.060 6.090 8.130 10.16 12.19

11

11;

10 2.080 4.170 6.250 8.330 10.12 12.50 14.58 16.67 18.75 20.83 22.92 101 2.140 4.270 6.410 8.540 10.68 12.81 14.95 17.08 19.22 21.35 23.49 10/1/ 2.190 4.380 6.560, 8.750 10.91 13.13 15.31 17.50 19.69 21.88 24.06 103 2.240 4.480 6.720 8.960 11.20 13.44 15.68 11 2.290 4.580 6.880 9.170 11.46 13.75 16.04 111 2.340 4.690 7.030 9.380 11.72 14.06 16.41 18.75 21.09 23.44 25.78 2.400 4.790 7.190 9.580 11.98 14.38 16.77 19.17 21.56 23.96 26.35 2.450 4.900 7.340 9.790 12.24 14.69 17.14 19.58 22.03 24.48 26.93

17.92 20.16 22.40 24.64

18.33 20.63 22.92 25.21

12

2.500 5.000 7.500 10.000 12.50 15.00 17.50 20.00 22.50 25.00 27.50