The Viaduct Works' Handbook

00 centre, in 15-feet lengths, scarfed over each trestle, and attached to the lattice girders by bolts; these joists are covered all over with 4-inch planking. The whole is strong enough to carry a load of 1 cwt. per superficial foot, distributed all over its surface. A strong wrought-iron waleing is connected to each trestle at low-water level, and continued on both sides and front; and another at high-water level, which extends along the front and up-stream side. Iron stairs are provided for convenience of passengers landing at any state of tide, and the platform is complete with tram-plates and crane for convenience in landing merchandize. The weight of ironwork in this structure, ex- clusive of tram-plates, is about 10 cwt. per foot run, and taking the price at £16 per ton, f. o. b., would give the cost at £8 per foot run. The cost of timber, fitted and prepared, would, probably, add about £3 per foot run; but this will depend very much upon circumstances special to the locality in which it would be required. The engraving at page 56, of a bridge made at Crumlin, for erection in England, serves to illustrate the principle of cast-iron screw piles applied to jetties. This bridge is about 5000 feet, or nearly a mile in length; is a class of work equally applicable for