will be given to screw-bolts of soft steel with cold-pressed threads.

All bolts must be practically perfect in every respect, and wherever necessary, they must be provided with nuts and threads of the standard size required for their diameter. The thickness of a nut shall not be less than the diameter of the rod for which it is intended, and the side of a square nut must not be less than twice the diameter of the bolt. The heads of all bolts shall be of the same size as the nuts required for the screw ends. All screw-bolts, drift-bolts, and dowel-pins shill be made truly straight before being driven, and all nuts must be screwed up tight against the washers. All nuts and heads of bolts must have heavy O.G. washers between them and the timber. All washers are to be made of cast iron of good quality, and must he sufficiently large and thick to provide properly for distributing the pressure due to the greatest allowable tension in the bolts over the area of the washers. They must be finished in a neat and workmanlike manner, and must be free from air-holes, cracks, cinders, and other defects. All spacers are to be made of cast iron, unless otherwise specified, and must be of the same quality and finish as specified for the washers.

ERECTION, DEFECTIVE WORK, DIRECTIONS TO CONTRACTOR, CLOSING THOROUGHFARES, RESPONSIBILITY FOR ACCIDENTS, DAMAGES, ALTERATION OF PLANS, STRICTNESS OF INSPECTION, SPIRIT OF THE SPECIFICATIONS, ENGINEER, AND TENDERS.

See Chapter XVIII. [pages 261-264]