420 SEVENTH REPORT—1837. 
read on the 7th March, 1837. He observes, “‘ I cannot con- 
clude this paper without again pointing out that a great number 
of curious facts in fluid motion are established by these tide re- 
searches, of which it may be hoped that the theory of hydro- 
dynamics will one day be able to render a reason.” It was, 
therefore, necessary to investigate the subject of the terrestrial 
mechanism of the tides, that is, to determine the nature of the 
mechanism by which this tide wave is transferred from one 
part of the waters of a given channel to another. At the 
meeting of the Association at Bristol, Mr. Whewell had ex- 
pressed his opinion that the great primary wave of Mr. Russell 
and the tidal wave would be identified. 
The effect of wind upon the propagation of the tide wave 
was also a subject of importance. The magnitude of the tide 
is admitted generally to be affected by it in some way, but it is 
matter of doubt, whether the time of the tide, or rather the 
velocity of the tide wave, is at all affected. M.Daussy denies the 
existence of such an effect in the French observations, while it 
has been found by Mr. Lubbock in the London tides. It was 
necessary to determine this point with great accuracy. 
Besides their direct and theoretical use, there was another 
point of some importance in these researches concerning the 
tide wave, viz., that if the tide wave should be found to obey 
the law of the great primary wave of fluid, we should be put in 
possession of the principles on which the improvement of tidal 
rivers might be effected. 
Method of Inquiry.—The following order was adopted. by 
the Committee in the means by which they endeavoured to 
carry on the inquiry with which they were entrusted : 
The observations on the nature of the tide wave were those 
which it was important to obtain in the first place, as they 
required peculiar facilities which were not likely to be readily 
found. 
Fortunately it occurred to one of the Committee that the 
river Dee in Cheshire was peculiarly suitable to their purpose. 
It was their object to determine whether the same law which 
regulated the propagation of the wave previously examined by 
Mr. Russell in experimental canals, was followed by the tide 
wave in its propagation, or whether the velocity of the tide 
wave were proportional to a certain depth in a certain form of 
channel. It was necessary for this purpose that a channel of 
uniform dimensions should be obtained which could be easily 
measured, and which should possess a tidal wave capable of 
being easily observed. Now it happened that the river Dee is, 
