ON WAVES. 429 
presented on the surface of an agitated sea. This wave presents 
simply the phenomenon of an elevation of fluid transferred 
from place to place of the fluid, finding the fluid perfectly at 
rest, and leaving it in an equally perfect state of equilibrium. 
Many philosophers have examined the theory of waves, but 
they all appear to have considered only the oscillatory, success- 
ive, and gregarious waves. Newron considered them as re- 
presented by the oscillations of a column of fluid in a bent tube, 
and assigned to them laws analogous to those of the pendu- 
lum; GRANESAUDE followed the theory of Newton; D’ALEmM- 
BERT adopted Newton’s theory, and pursued this investigation 
considerably further ; and LaGRancE improved it by removing 
some former limitations inconsistent with the phenomena ; 
LapuaceE formed a new theory, in which the oscillatory waves 
are supposed to be formed by immersing a solid of a given form 
in the fluid and suddenly withdrawing it; GEeRsTNER gives a 
very beautiful theory of waves, in which the observed phenomena 
of oscillatory waves of the larger class are very accurately re- 
presented; Poisson, Caucny, and Fourier have discussed 
the mathematico-physical question of very minute oscillatory 
waves with so much success, as to represent some of the phe- 
nomena with considerable accuracy; and the results of these 
theoretical views have been examined very carefully in the ex- 
periments of BREMoNTIER, FLAUGERGUES, Bipong, and the 
Wesers. But in none of these inquiries has the phenomenon 
of the solitary wave attracted any attention; and, indeed, so 
far from having been satisfactorily examined, its very existence 
does not appear ever to have been distinctly recognised. 
This solitary progressive elevation appears to be the wave of 
the first order, and has been called by Mr. Russell the Great 
Primary Wave of the fluid. And its phenomena are of that 
invariable and decided character, which claim for it such a di- 
stinction. 
The great primary wave was first observed by Mr. Russell in 
1834. By the impulse of a vessel drawn by horses a consider- 
able portion of fluid was raised above the level of the rest 
of the fluid in a channel of limited breadth and depth. The 
elevation thus formed was observed to assume a peculiar and 
regular shape extending across the whole breadth of the 
channel, and to propagate itself along the surface of the quies- 
cent fluid with a velocity of nearly eight miles an hour; which 
velocity and form appeared to continue unchanged, although 
followed for about the distance of a mile. 
The following experiments were made for the purpose of 
determining whether the velocity of this wave were not affected 
