428 SEVENTH REPORT—1837. 
First Series of Observations. 
Experiments on Waves in Artificial Reservoirs.—As this 
portion of the experiments was made in continuation of a series 
of experiments in which Mr. Russell had been previously en- 
gaged, and of which he from time to time announced the results 
to the British Association at Dublin and at Bristol, and as these 
notices were omitted in the last volume of the Report, but pro- 
mised by the Secretary to be included in the present one, it will 
be proper to state what had been brought to light in those ex- 
periments on waves previous to the appointment of this Com- 
mittee. 
At the Dublin meeting of the Association Mr. Russell stated 
that he had been induced to make a series of experiments on 
waves in certain circumstances, from having found that the re- 
sistance of fluids to the motion of floating bodies was very much 
affected by the phenomena of the waves generated in the fluid 
by the motion of these bodies; and that many of the imper- 
fections of that part of hydrodynamical science which treats of 
the resistance of fluids, would be removed by an acquaintance 
with the laws of the motion of waves. One of the great in~ 
stances of deficiency in our theoretical knowledge, when ap- 
plied to practical uses, occurred in the question of the force re- 
quired to give motion to a vessel in a confined channel, a canal, 
or a small river; in these cases a vessel at certain points of her 
progress encountered extreme resistance, and at other, still 
higher velocities, experienced diminutions of resistance equally 
extraordinary and anomalous. These facts had set at defiance 
all previous theory ; but it was found that a knowledge of the 
laws of the generation and propagation of waves in a fluid was 
all that was required to solve these difficulties and to remove 
these anomalies. For this purpose he had undertaken a series 
of experiments on waves carried on during the years 1834 and 
1835. 
The WAVE which had been thus found to form so important 
an element in the resistance of fluids, was found to be a phe- 
nomenon of a very different nature from those waves which had 
previously occupied the attention of the physical investigator. 
This phenomenon presents itself as a Sotirary ProGreEssivE 
ELevation of the surface of a quiescent fluid, neither preceded 
nor followed by any secondary or successive phenomena, to- 
tally distinct from the oscillatory waves, and from such waves as 
the ripple on the surface of a lake agitated by the wind, and the 
concentric circular oscillations of a calm sheet of water into 
which a stone has been dropped, and from the waves which are 
