CONNECTING ROD OF SCREW ENGINES OF GREAT EASTERN STEAMER.

BY BOULTON, WATT, AND CO.

PISTON OF SCREW ENGINES OF GREAT EASTERN STEAMER, BY BOULTON, WATT, AND CO. Section and Plan.

Figs. 385 and 386 are side and edge views of the connecting rod. The cylinders upon the one side of the vessel have each one conecting rod of this kind, and the cylinders upon the other side of the essel have each two connecting rods of the same description but of

The large end of the connecting rod is the crank end; the small end being that which is affixed to the cross-head.

The brasses of the connecting rod it will be seen are furnished both above and below the bearing with a plate of wrought iron, through which the bolts constituting the connecting rod also pass, to the end that if the brasses should heat and crack at any time the connecting rod will not nevertheless be disabled. This is a provision which ought to be introduced into all bearings of this character. Owing to the large size of the crank-pin consequent on its forming an integral part of the shaft, the crank-pin brass is necessarily very large, and the rods composing the connecting rod are therefore thrown wider apart at the crank-pin end than at the cross-head end. They have consequently to be bent slightly at the neck where they enter each brass, and this bend is a disadvantage. The combination, therefore, does not work in so well as in the case of the connecting rod of the Barwon, where the cross-head and crank-pin being of about the same diameter the rods are straight. In engines of this class it does not appear to us that a simpler species of connecting rod than this could be made, and its action in practice is found to be perfectly satisfactory.

The Great Eastern, it is well known, is propelled both by paddles at the sides and by a screw at the stern, an arrangement which presents various advantages, no doubt, in adding to the efficiency of the vessel.* But it is one which adds to the complication of the machinery, and upon the whole a better arrangement of the machinery than what actually exists in that vessel could no doubt be effected. In our judgment, it would have been preferable to have made the screw

I believe that the suggestion of the combined use of the screw and paddles was first made by myself. It was published in my treatise on the Screw Propeller in 1851, but several years before that I recommended the Peninsular and Oriental Steam Company to accelerate their slow paddle vessels by adding a screw in the stern, which screw was to be driven by a high pressure engine-the steam proceeding from which was to drive the low pressure paddle engines previously in use. - J. B.

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