4-2 APPENDIX. 



of the cranks with a moveable boss, which revolves upon the fixed centre A. One of these 

 arms is fixed to the boss, and is termed the dividing arm. 



It will thus be seen, that in consequence of the point A being situated out of the centre, the 

 paddles will assume different positions during the revolution of the wheel, which positions 

 can be so arranged as to differ very little from the vertical wheel, while passing the lower part 

 of the revolution, or that part where the action of the paddle takes place. 



In the year 1837, Messrs. Seawards fitted a vertically acting wheel to the ' Levant' steam 

 boat, in which the positions of the paddles are similar to the above, but are brought about by 

 a different arrangement of machinery. This wheel formed the subject of a charge of piracy, 

 on the grounds of being a colourable evasion of the patent of Elijah Galloway. The Vice- 

 Chancellor having given judgment against granting an injunction, the parties tried an action 

 at law, in which they were also unsuccessful ; and Messrs. Seawards have now the privilege of 

 making these wheels. 



Fig. 3. and 4. is a representation of Seawards' wheels. A A is the shaft of the engine, 

 to which the two frames or polygons B B, C C are attached. D D D D are the paddles, 

 which revolve in bearing in the two frames. E E is an enlarged axle fixed to the side of 

 the vessel excentrically with the shaft, and answers the same purpose in giving the requisite 

 positions to the paddles as the cranked axis A in Morgan's wheel. F F is a rim of iron, 

 which is caused to revolve on the enlarged axle by an arm G attached to the inner polygon of 

 the wheel : from this rim proceed arms or rods H H H, to the bent cranks III, attached to 

 the paddle boards. 



It will here be seen, that the paddles will in like manner, by the motion of the wheel, take 

 up positions similar to those of Morgan's, entering and leaving the water nearly in a vertical 

 position. The main difference in the construction of the two is the excentric, which by 

 being fixed at the side of the vessel, instead of in the centre of the wheel, is less adapted to 

 giving motion to the paddles, from acting at one end of them, but has the advantage of 

 allowing the shafts to be continued through the wheel, which certainly adds to its strength. 



EXPERIMENTS ON PADDLE WHEELS. 



For the purpose of instituting a comparison and explaining the action of these wheels, I 

 have given the following set of experiments on her Majesty's vessels, fitted out at Woolwich, 

 some of which are provided with Morgan's wheels, and others with the radiating wheel. 

 Each vessel is submitted to accurate experiment, sometimes when light, and sometimes laden. 

 The exact amounts of their cargoes are known, their registered and actual tonnage, area of 

 paddle, and every other particular which can serve as a guide to such an inquiry. 



