64,850 1,300 cubic yards of parapet walls, at $12 15,600 520 cubic yards of brick walls and wells, at $12 6,240 250 cubic yards of coping on parapets, at $30 7,500

29,340 4,400 cubic yards of foundation walls at ends, at $2 8,800 400 cubic yards of side wall on do. at $6 - 2,400

11,200

166 MEMOIR OF THE 6,500 cubic yards of earth filling over pipes, at 40 cents - 2,600 350 superficial yards turfing, at 30 cents - 105

2,705 1,000,000 ft. board measure, pine timber arid plank for centering and - scaffolding, at $35 35,000 300,000 ft. board measure, oak timber and plank for centering and - scaffolding, at $45 13,500

48,500 580 tons cast iron pipe, at $75 43,500 Lead, yarn, tallow, and laying down, estimated 9,000 2 pipe chambers, as per estimate detailed in report December, 1837, - 15,642 Waste cocks, as per report December, 1837, - 2,500

70,642

$760,557 Add for contingencies 10 per cent. 76,056

$836,613

Tunnel under the Channel of the River.

By the Act before mentioned, it is required that the top of the work put down for the tunnel, shall not be above the bed of the river in the channel ; and it is understood as requiring the tunnel to extend entirely across the channel, which at the line of aqueduct is 300 feet wide. The bed of the river is about 18 feet below common high water mark. The channel is not this depth for its whole width, but slopes very flat on the sides. The outline of the plan, is to make a tunnel of masonry, of sufficient dimensions to allow four iron pipes, each three feet diameter to be laid within it. The tunnel to be made of two sections, or of two arched vaults, laid close to each other, and each sufficient for two pipes.