1829.

106 STEAM NAVIGATION.

be always directed to the centre O, but are so placed that they arecapable of turning on axles which are always horizontal, so that theycan take any angle with respect to the water which may be given tothem. From the centres, or the line joining the pivots on which thesepaddle-boards turn, there proceed short arms K, firmly fixed to thepaddle-boards at an angle of about 120°. On a motion given to thisarm K, it will therefore give a corresponding angular motion to thepaddle-board, so as to make it turn on its pivots. At the extremitiesof the several arms marked K is a pin or pivot, to which the extre-mities of the radial arms L are severally attached, so that the angle

between each radial arm L and the short paddle-arm K is capable ofbeing changed by any motion imparted to L: the radial arms areconnected at the other end with a centre, round which they are ca-pable of revolving.