-------------------------------+-------------+-------------+ | Four Sets. | Six Sets. | | 37/10 | 37/10 | -------------------------------+-------------+-------------+ Area, square inches | 2·0 | 3·0 | Area, square millimetres | 1290 | 1935 | Weight per 100 yards run lb. | 4612 | 6918 | Cost of copper at 7¾_d._ | 149 0 0 | 224 0 0 | Cost of insulation | 283 0 0 | 424 0 0 | +-------------+-------------+ Total cost of Cables | 432 0 0 | 648 0 0 | Casing, bitumen, and cement | 40 0 0 | 55 0 0 | Labour, Laying | 35 0 0 | 50 0 0 | Trenching and repairing | 30 0 0 | 35 0 0 | Surface boxes and connection | 10 0 0 | 10 0 0 | Engineer and superintendent | 20 0 0 | 25 0 0 | +-------------+-------------+ Total | 567 0 0 | 823 0 0 | Add extra if copper, at | | | 9½_d._ | 34 0 0 | 51 0 0 | +-------------+-------------+ | 601 0 0 | 874 0 0 | Cost of copper per lb., | | | laid complete | 0 2 7¼ | 0 2 6¼ | Current in ampères | 720 | 1,080 | Cost per ampère | 0 16 8 | 0 16 1 | -------------------------------+-------------+-------------+ TABLE II. _Cost of Laying 100 Yards of Double Conductor of Bare Copper carried on Insulators in a Culvert._