Five locks besides the guard lock will be required : If these extend each 70 feet, and the projections beyond each 50 feet more the whole extent will be 720 feet But as all tlie work must be double on each side, the whole length will be 2880 feet : If tlie timber be 12 inches squares, and the sides 10 feet high, it will require 28,800 cubic feet. For bottom sills, one to every 3 feet, is 180 of 30 feet long, equal to 5400 cubic feet.-- 360 posts, 10 feet long, is 3600 cubic feet. Braces to cross Irom the interior to the exterior side -- one for

INLAND LOCK-NAVIGATION. 1105

every four feet is 180 for a side, or SCO for both sides, multiplied by 10 in height, is 3600, and by 10 in length is 36000 ; but as these require to be only 5 by 7 inches, the cubic feet will be about 9000. -- For gates about 3000 cubic feet, is in all 46200 cubic feet, at 30s. per

hundred is 693

Filling in witli earth, raming the same, about 72000

feet at 100 feet per day for one man at 4s. is 144

500 Plank of 3 inches thick, for tlie bottom, at 4s. is 100

250 Plank of 3 inches thick, for the gates, at 4

shillings is , 50

Spikes, iron work, &c 200

Framing, 30 carpenters, 100 days at 9s 1350

House fur the officer to attend the locks and receive