ON WAVES. 



367 



The form under which these waves appear has already been exhibited in 

 Plate LII. figs.9 and 10, and equally in Plate LV. iigs. 1,2, 3, and in Plate LVI. 

 fig.l. 



I have made a series of observations by dragging a body through the water, 

 the results of which are given in the following Table. I first made pre- 

 paratory observations to find whether the form of body or depth of channel 

 made any change on the phsenomenon. I found that larger bodies and higher 

 velocities made higher waves, but that the length and velocity of the wave 

 were unchanged by either the form of body, or tlie depth of the channel, or 

 the height of the wave. I observed that when the waves became high and 

 broke, the elevation above the mean level was 6 inches, and the depression 

 below it 2 inches, making a height total of 8 inches ; this was at a velocity 

 of 6*25 feet per second. Immediately behind the body dragged through the 

 water, the mean level appears to be considerably lowered. 



I examined the motion of oscillation of these waves by means of small 

 floating spherules. Waves of the second order having a total height of half 

 an inch, in water 4 inches deep made by a negative wave, were accom- 

 panied by motion in a circle of half an inch diameter at the surface, and the 

 particles below described also circles which rapidly decreased in diameter 

 and at 3 inches deep ceased to be sensible ; the Avaves were about one foot 

 long. 



Table XIX. 



Observations on the Length and Velocity of Waves of the Second Order. 



Column A the order and number of the experiments. 



Column B the number of seconds in Avhich the waves were transmitted 

 along 100 feet. 



Column C the aggregate length in feet of the number of waves in Column 

 D. 



Column D the number of waves extending to the length in Column C. 



Column E the length in feet of one wave from crest to crest. 



Column F the velocity in feet per second given by experiment. 



These results are the means of many experiments, differing from each 

 other not more than the examples preceding them, which have been given in 

 detail as a fair specimen. 



