ON PADDLE WHEELS. 41 



at right angles to each other : the revolution of the floats or paddles in the water creates a 

 resistance upon them, and the corresponding reaction on the main shafts produces the force 

 by which the vessel is propelled. 



It is evident, that in this construction of wheel two kinds of lost power must exist : first, by 

 the action of the paddle being oblique, or at an angle with the horizontal direction of the vessel 

 in every position except the vertical one, by which of course only a portion of the power 

 exerted on the paddle becomes effective ; and secondly, by -the receding of the wheel in the 

 water necessary to create a resistance equal to the force applied by the engine. This may 

 perhaps be best illustrated by the case of a locomotive engine : if the friction between the 

 wheel and the rail be such that the former does not slip, the motion of the carriage will be the 

 same as that of the circumference of the wheel ; the whole power of the engine is employed 

 in propelling the carriage, and consequently there is no lost power : but if the friction be not 

 sufficient, the wheel will slip back some quantity ; the same steam will be consumed in the 

 revolution of the wheel, but the carriage will not be advanced as before, and there will be a 

 loss of power proportional to the skidding or receding of the wheel : so also in a steam 

 vessel all that the centre of pressure actually goes back in the water, or all that its circum- 

 ferential velocity exceeds that of the vessel, is comparatively lost power ; the expense of the 

 steam being proportional to the former, and the effect to the latter. 



This source of lost power must of course exist in all paddle wheels, whatever their con- 

 struction, from the resistance being created in a fluid ; but that kind first described being 

 owing entirely to the radiation of the paddles, a great number of inventions have been pro- 

 posed to remedy the evil, by causing them to keep a vertical position by the aid of machinery 

 during their progress through the water. These wheels, although they possess much supe- 

 riority over the ordinary construction in a sea, or where the wheel is deeply immersed, by 

 obviating the loss of power from the obliquity of action and back water, are subject to evils of 

 another description ; and it is a question of doubt, whether the common radiating wheel does 

 not admit of a construction, which, in average of weather and circumstances attending a sea 

 voyage, might lead to as little loss of power as the vertical wheel, and at the same time 

 possess the advantage of less liability to derangement. 



The first vertically acting wheel which has been employed to any extent in this country is 

 that commonly known as Morgan's Wheel. The original patent for this construction was 

 granted to Elijah Galloway, and sold by him to Mr. William Morgan ; but has since that 

 time undergone considerable improvements in its structure and arrangement, and is now 

 extensively adopted by Government in the Admiralty steamers. 



Fig. 1. and 2. are a plan and elevation of the improved wheel : a a a a are paddles, which 

 turn upon spindles having a bearing on the framework, c c c, and of the wheel, which is of a 

 polygonal figure, having as many sides as it is required to have paddles. The inside frame or 

 polygon is alone attached to the shaft of the engine, which does not continue beyond the side 

 of the vessel ; and the outer one has an independent bearing on a centre attached to the paddle 

 box, so that it derives its motion entirely from the arms or angles of the polygon ; the space be- 

 tween the two frames of the wheels being left quite free. A is a crank fixed to the paddle box, 

 upon which the outer polygon revolves ; it projects in an inclined direction in the open space 

 between the sides of the wheel, but to a point considerably excentric with it. Each paddle 

 has a crank attached to it at an angle of about 70, and arms a a, 8tc. connect the extremity 



