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DETAILS OF (PADDLE-WHEEL)'

The side elevation represents the eccentricat half stroke, also the sliding quadrant andworking lever. The eccentric has attachedto it a portion termed a counter-balance, theutility of which is that the eccentric—beingloose on the shaft—retains a horizontal orequilibrium position when the rod is discon-nected from the sliding quadrant. For thepurpose of fixing the eccentric at the requisiteangle, for going ahead or astern, stop pins areinserted in the crank shaft, projecting beyondthe periphery. A provision on the boss of theeccentric bears against either pin when the rodis in gear; the direction of the rotative move-ment causing the constant contact of the pinand eccentric boss. On disconnecting theeccentric rod, the eccentric retains the equili-brium position—already alluded to—andremains stationary until the pin comes in con-tact with the provision in question, by therotation of the shaft.

Next, attention must be given to the startinggear. Presuming the engines are to be stopped,the hand lever—level with the top of thestarting wheel—is pushed towards the eccen-tric rod, and the lower end of the lever—beingcranked into a slot in the rod—forces the rodfrom its bearing on the quadrant pin. Thepin then works in the loop secured to thefront side of the rod, and the cranked end ofthe lever prevents the eccentric rod returningto its bearing. When the engines require to bestarted, the hand wheel is used as a preliminarymeans for working the slide valves. Now,assume that the eccentric rod is disengaged asdescribed, the action of the slide valves isindependent of the eccentric. The positionof the starting wheel will be as that seen

in the drawing under notice ; although theeccentric rod is shown connected,—this isonly for the means of representing theapplication of the gear in question. Onreferring to the end elevation, it will benoticed that on the starting wheel shaft apinion is secured, and this gears into a rack, thelatter being secured to the sliding quadrant.Now, on turning the pinion, the rack ascendsor descends, as may be required, and thus amovement is imparted to the slide valvessimilar to that derived from the eccentric.The plan of the starting gear, between theelevations, conveys a ready conception as tothe connection of the several portions of thedetail, and the sectional plan of the workinggear—under the side elevation—depicts theangles requisite for the levers and positionof the quadrant, and means for guiding thesame.

Plaving thus far become acquainted withthe requisitions and the mechanical means toacquire the same, attention devoted to theadvantage of the arrangement will not bemisapplied. Suppose a ship, fitted with oscil-lating paddle engines, and single eccentricmotion and starting gear, as shown, is requiredto be reversed in her way as speedily as pos-sible, the application of the gear in ques-tion will be thus apparent. The eccentricrod is thrown out of gear—as explained—andthe starting pinion pushed in gear with therack, the quadrant imparts the requiredmotion to the slide valves, to cause the steamto enter the cylinders at the opposite ends—the direction of turning the wheel of coursedetermining this latter effect. On the enginestarting, the eccentric rod can be set on the