ON SHIP WA VES. 477 



trade by want of water, drought having reduced 

 the depth from 12 to 5 feet. It was now found 

 that the motion of the light boats was rendered 

 more easy than before ; the cause is obvious. The 

 velocity of the wave was so much reduced by the 

 diminished depth, that, instead of remaining behind 

 the wave, the vessels rode on its summit." He also 

 makes this interesting statement : " I am also 

 informed by Mr. Smith of Philadelphia, that he 

 'distinctly recollects the circumstance of having 

 travelled on the Pennsylvania Canal in 1833, when 

 one of the levels was not fully supplied with water, 

 the works having been recently executed, and not 

 being yet perfectly finished. This canal was 

 intended for 5 feet of water, but near Silversford 

 the depth did not exceed 2 feet ; and Mr. Smith 

 distinctly recollects having observed to his astonish- 

 ment, that, on entering this portion, the vessel 

 ceased to ground at the stern, and was drawn 

 along with much greater apparent ease than on 

 the deeper portions of the canal." 



Even if one regretted the introduction of rail- 

 ways, do not imagine that it can be set forth on 



