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working constantly in oil, is placed in the center foundation. The connection between the pillar and the bearing is such, that, should the foundation set- tle in a one-sided manner, no detri- mental consequences would follow. The bearing is protected' against dirt 'or moisture by means of an oil+box cover- ing. At the upper part of the support- Feq. 186420 - "HAE Marine. REVIEW which transmit the movement through pinion to spur-wheels, which act upon the driving-rack fitted to the pressure ring: This driving-rack is made of steel angle-bars, the teeth consisting of turned steel bolts, which, in case of wear, can, without trouble, be replaced. by new ones. The two lifting-gears are placed on 1 DE + pulley. "The aring -- ietenen the drums is actuate: entirely by put wheels.. The coupling of the two | ing gears is effected by means of a wheel in a simple manner. In order t hold : the load a the Bilibe easily on 'ball vedere. 5 Figéi 150-TON HAMMER DERRICKING CRANE AT BIRKENHEAD. oe ing structure the tipping forces are taken by a roller-anchor bearing, as may be seen in.the general views, and in Figs. 4 to 8. From these it will be seen that around the vertical pillar are placed six pressure rollers, which on a ring-shaped rail fastened to the inside of the pressure ring. The turning gear. consists of two equal driving gears, each driven by a separate motor; these motors work on two worm gears with quick threads, run the main platform, and are driven by a motor alternately, the 50-ton lifting gear being placed behind the other. For this load six strands of steel rope are used, of which two are simultaneously wound on two drums of large diameter, ; placed alongside each other, as shown . in Figs. 4 and 5. The lifting-gear for the 150-ton load is placed forward, and has two rope-drums, situated one be- hind the other. Each of these drums winds up one rope of the 10-rope-ply Leaving the lifting-gear, we come next to the derricking-gear, which is placed on the top staging. The luffing is performed by means of two heavy steel spindles, which are screwed into ie nuts of manganese-bronze, fixed to the jib in such a manner. that, when the spindles rotate, the jib may thereby be raised or lowered. The nuts, as well as the ends of the spindles, rest on cross-bearings which pivot round horizontal axes. The two *