448 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK iv. 



Great is the interval to-day between Fulton's and Bell's steamers 

 and the grand transatlantic steamships which regularly cross from 

 the old to the new world. The progress of steam navigation in the 

 last sixty-five years has been immense, but we must not forget 

 the share which belongs to each of those inventors who without 

 being discouraged have worked for this end, from the modest Papin 

 up to Fulton and Bell. 



II. PADDLE STEAMERS. 



When the power of steam was discovered, the idea had long been 

 conceived and even tried of replacing the oars by wheels to be turned 

 by the muscular action of men or animals. The Eomans and Car- 

 thaginians had long before used boats which were moved by paddle- 

 wheels, ancient medals represented the liburnce (the ships employed 

 by the Eomans at Actium) with three oars of paddle-wheels along 

 the sides turned by three pairs of bullocks. We read that l "in 

 China, where they have been used from time immemorial, are 

 to be seen juriks with four wheels, moved by an ingenious crank 

 worked by men." In 1472, Yalturius de Eimini described a 

 wheel the shaft of which was moved by men by means of bent 

 cranks, and in which paddles replaced oars. A similar propeller was 

 proposed in 1699, by Du Quet to the Academy of Sciences in Paris. 

 When Papin, a few years earlier, proposed to apply steam to ships, he 

 mentioned the rowing wheel of Prince Palatine Eupert's sloop, which 

 he had seen in England in 1678. These wheels were moved by 

 horses yoked to a beam. 



This method of propulsion could not be seriously adopted till 

 after the discovery and application of a powerful motor, and we have 

 just seen that this motor is steam. It is only therefore since Fulton's 

 and Bell's time that rivers, lakes, and seas, have been furrowed by 

 ships and boats provided with paddle-wheels that is, the well-known 

 arrangement by which a kind of water-wheel on each side the ship 

 is set in motion. 



The paddle-boards, which radiate all round the axis, and are 



1 Ribliotheque des Men-cities. 



