(i-2 



APPENDIX. 



practicable, the best remedy is the use of the vertically acting or cycloidal wheel, and keeping 

 the diameter as large as possible, by increasing the length of the stroke of the engine, so 

 that more or less immersion will make comparatively less difference in the action of the 

 wheel ; the larger the vessel the less will be the loss, because the diameter of the wheel 

 increases in a greater ratio than the degree of immersion. In the Victoria, which is fitted 

 with the cycloidal wheels, it is proposed to remove the outer paddles before starting, and 

 to replace them during the voyage when the vessel is sufficiently light, which, if it can be 

 effected, will be attended with considerable advantage ; but much less than if a ready 

 method of reefing could be devised, so that the surface of the paddle-board should be at the 

 constant command of the engineer. 



EXPERIMENTS TO ASCERTAIN THE RATIO OF THE SPEED OF A STEAM BOAT 



TO THE POWER. 



By the preceding investigations we learn, that the speed of a vessel varies theoretically as the 

 cube root of the power effectively developed. In vessels destined for long voyages, where a 

 great number of miles has to be travelled before a fresh supply of coals can be taken on 

 board, it becomes of importance to ascertain by experiment how far this law is consistent with 

 practice. The attention of Professor Barlow, as one of the Commissioners appointed by 

 Government to report upon the communication to America by steam boats from Valentia, 

 was directed to this subject, and he obtained the permission of the Admiralty to make some 

 experiments on her Majesty's ships Echo and Lightning, the results of which, with the 

 reports accompanying them, are as follows. 



TABLE VI. Experiments on her Majesty's ship Lightning, to ascertain the dif- 

 ference of speed due to different amounts of steam power ; taken in successive 

 hours by Massey's Patent Logs, between 8 h. A. M. and 3 P. M., November 15th, 

 1836. 



