One advantage of the derrick type is that the crane may be placed close to the edge of the quay; in this case the centre is only 7 ft. from the front of the wharf, so that the full load of 120 tons can be dealt with at an effective outreach of 63 ft. from the quay. The maximum radius of the heavy purchase with a load of over 60 tons is 90 ft., and of the light purchase gear, with a load of 10 tons, 98 ft. The minimum radius of the crane is 25 ft. There are four sets of gear: for lifting heavy loads, for raising light weights, for derricking the jib, and for slewing; a separate controller of the enclosed tramway type is provided for each. The main hoisting and derricking motors are of 50 horse-power, and the others of 35 horse-power. The speed of hoisting 120 tons is 5 ft. per minute, while a 10-ton load is raised at the rate of 40 ft. per minute. Automatic brakes are fitted for the slewing motion, and powerful hand-brakes for the hoisting and derricking gears. All motions are controlled by one man in the steelhouse fixed to the mast of the crane 56 ft. above the quay level. There is on the opposite wharf of the dock a 20-ton travelling electric crane, and throughout the Works there are many portable and hydraulic cranes, in addition to the hydraulic and other cranes commanding the machine tools. Reference may here be made to the Company's graving dock, illustrated on Plate XLV., adjoining page 101. The length is 360 ft., and it is largely used for docking ships for repair, as well as for cleaning ships preparatory to trial. Our view shows a torpedo-boat destroyer in the dock. The pumps for the emptying of the dock are electrically driven. We may return now to our narrative of the construction of a ship, and deal with the supplementary departments, including those of joiners, smiths, plumbers, sheet-iron, and other workers.