ON WAVES. 445 
other; the wave on entering the channel at A was observed ; 
its height was again taken at B, when it had advanced half 
the length of the channel, and had been diminished one half 
in breadth ; and at C, after having passed along three-fourths of 
the length of the. channel, the height was again observed. 
The wave was observed breaking invariably at the height of 
about 3°6 inches above the level of the fluid; and the distance 
from D, the end of the channel, when it broke, is given with 
the sign minus prefixed. On entering the channel the wave 
was low, but gradually increased as it reached the narrower 
parts of the channel, becoming acuminated ; and at last having 
gained the cusped cycloidal form, broke at the crest, and passed 
into the centre angle of the wedge, when it rose suddenly 
over the sides of the channel in a sharp vertical jet d’eau. A 
table of these experiments is given at the end, comprehending 
Waves XCIV.—CVI. 
The sloping channel, Plate II. fig. 6, was formed to imitate 
a sloping sea beach ; its slope rose 1 in 51. The wave entered 
the deep end at a given height, then gradually became more acu- 
minated, formed a cycloidal cusp, and broke. Its height on 
entering, its height when breaking, and the place at which it 
broke were observed and are given in the observations at the end 
from Wave CVII. to CX XXII. The numbers in the last column 
are the depths corresponding to the place of breaking observed 
in the preceding column, and this table shows that the depth at 
breaking corresponds with remarkable accuracy to the height of 
the wave. _ 
A considerable number of observations were made upon the 
translation of the particles of the fluid during the transit of a 
wave, but the results are not of a numerical character, being 
all comprehended in the general expression that the translation 
of the particles takes place wholly in the direction of the motion 
of the wave; that it is of equal extent from the surface to the 
bottom of the channel, that it is permanent, that the particles 
which were in the same vertical plane previous to translation 
are still so after translation. This is not the case in other 
species of waves ; the particles oscillate in opposite directions 
with an alternating motion. 
Experiments were also made on waves formed by the removal 
of a solid body from a quiescent fluid ; these are called negative 
waves, but the investigation of them has not yet been completed. 
Second Series of Observations. 
On the Waves of the Sea.—Are the waves on the surface of 
the sea, when it is agitated by the wind, of the same nature with 
the waves which have already been examined by experiment ? 
