Engineering Wonders of the World
Volume III

368 ENGINEERING WONDERS OF THE WORLD. Fig. 19.—MODERN DY- NAMOMETER GEAR. ing-back machinery is usually provided on large vessels intended for cable - laying in deep water. This is placed between the cable tanks and the Fig. 20.—bright’s holding-back gear. brake drum. It is sometimes constituted by several flanged wheels, each surrounded by a jockey pulley, thereby also providing a certain amount of tension before the cable reaches the drum. Another and perhaps preferable form of auxiliary gear consists (as depicted in Fig. 20) of a double row of semicircular cast-iron pieces, placed on a solidly constructed table. One row is fixed, and the other row arranged so that each segment piece is opposite a vacant space in the fixed row. The former can be moved to and fro across the table by a system of bevelled wheels and threaded spindles. The interval between the rows may thus be increased or diminished at will, thereby providing for a varying degree of friction imparted to the cable and a corre- sponding variation in the speed of paying out. This friction-table apparatus may be seen in position in Fig. 21. The same view also shows a double cylinder steam-engine fitted to the paying-out machine for the purposes already named. In the forward part of a telegraph ship stronger gear (in duplicate for each bow) is fitted, similar to that which has been de- scribed aft, but more powerful. It is furnished with toothed wheels and brakes, which latter are controlled direct from the machine itself, the dynamometer apparatus in this case only serving the purpose of measuring the strain. The machine is actuated by a powerful two- cylinde’ horizontal engine, and has already been referred to and partly illustrated in the earlier article, with reference to the recovery of the second Atlantic cable. The entire picking-up ap- paratus is shown in the general view of the Great Eastern (Fig. 14), including Fig. 21.—FRICTION TABLE ON T.S. “ DACIA.” the bow-baulks and sheaves over which a cable is picked up. Small repairing-ships only have, as a rule, forward gear, their