3*6 THE IMPROVEMENT OF 



(v) Drilling for Bolts. Tin- cost of drilling for bolts in the masonry, and of setting 

 them, shall be covered by the contractor's price for " Bolt-holes in Masonry." 



SILLS, CRIBS, AND LOCK-GATES. 



45. Classification. Timber in the lock-gates, in the miter-and coffer-sills, in the 

 cribs, and in the sheet piling of the wing-walls (and in the foundations), will be classi- 

 fied as " Timber in Permanent Construction." 



46. Quality. All timber in permanent construction shall be sawed, and shall be 

 of the full dimensions given, out of wind, free from large or loose knots, wind shakes, 

 splits, wane, dote, or any defect tending to impair its strength or durability. All 

 except that in the cribs and sheet-piling of the wing-walls must be dressed on all faces, 



and be of the full dimensions given after dressing; and shall be of , except that 



sills must be of first quality white oak. All dressed timber must receive one coat of 

 pure linseed oil on all sides and ends, as soon as dressed. 



The timber may be inspected on arrival at the work, and rejected at that time if 

 found to be defective; but this inspection will be only preliminary, and the final accept- 

 ance will not be made until the timber has been placed in the work. 



47. Miter-sills. The timbers for the miter-sills shall be selected sticks, neatly 

 fitted in place and set and grouted where needed with neat cement, to make water-tight 

 joints. They shall be secured with bolts as shown on the drawings and shall be set in 

 perfectly true line and position. The faces of the sills against which the gates rest 

 must be planed in place if necessary, so as to give a smooth and true fit. 



48. Cribs. There will be cribs, of dimensions and position shown on 



the drawings. They shall be built of io"Xio" timbers and filled with riprap. 



All timbers in these cribs shall be fastened at each intersection and at each end 

 with one drift-bolt, f inch square and generally 17 inches long. Stringers shall be 



feet long, placed to break joints vertically and horizontally; all those in the chamber 



faces of cribs shall break joint over a tie, with square sawed ends; the intermediate 

 and rear ones may break joint over a tie or midway between two ties ; in the latter case 

 a block 24 inches long shall be inserted under the joint, and two 28-inch drift-bolts 

 driven through the top stringer and the block into the stringer below. 



There shall be made and placed fastenings for rafts, of design shown on draw- 

 ing, all as directed by the Engineer. All drift-bolts shall have wedge points and 

 countersunk heads, and the contractor shall submit a sample for approval before order- 

 ing them ; they may be of either iron or steel. Holes shall be bored with |-inch augers. 



49. Ladders. Each crib shall have a recess cut for a ladder, and this ladder shall 

 be securely spiked to the crib with 40 wire nails. The ladder shall be of 2 by 4 inch 

 white oak or yellow pine, with round rungs of i-inch iron placed. . . .inches apart; the 



width of the ladder inside shall be 14 inches and the length for the lower crib feet, 



and for the upper crib feet, measured from the top of the crib. The stringers shall 



