20,000 pounds wrought iron bolts, straps and spikes, at 12 cents - - $2,400 Pin timber and treenails 250 Carpenter and other work, framing, sinking, and securing frame - 30,000 Driving 2,000 feet lineal of sheet piling, at $2 4,000 Driving 320 round piles at $3 cubic earth filling and embanking coffer, at 40 cents - 380,000 yards 15,200 Estimated cost of pumps, steam engines, and working, (very uncertain) 30,000 Removing frame, piling, earth of dam from the channel estimated 15,000 133,610 1,800 cubic yards brick masonry, at $18 - 32,400 8,000 cubic yards stone masonry and concrete, in abutments and tunnel, at $10 - 80,000 460 cubic yards coping and side facing of tunnel, at $30 - 13,800 2 entrance houses on abutments - 2,000 128,200 6,500 cubic yards stone embankment in river, between abutments and shores, at $2 - 13,000 3,000 cubic yards foundation and protection wall, at $2 50 - 7,500 20,500 700 tons iron pipes, delivered, at $75 - - 52,500 Lead, yarn, tallow, and work putting down 3,100 feet, at $4 - 12,400 13,000 cubic yards earth covering, at 20 cents - - 2,600 2 pipe chambers, as per detailed estimate of December, 1837 - 15,642 Waste cocks and man hole plates - 7,500 90,642

$424,492 Add for contingencies, 50 per cent. 212,246

$636,738 Aggregate estimate for bridge, - - $836,613 00 Aggregate estimate for tunnel, 636,738 00

Difference in favor of tunnel, $199,875 00

The items of which the estimate for the bridge is made, are for the greatest part of a character that give confidence in its being a fair approximation to the actual cost. The hydraulic foundations are the principal exception. In relation to the tunnel, the greatest part is peculiarly uncertain ; and it would not be surprising if unforseen difficulties should occur in its construction, that would materially reduce the difference that appears in the estimates.