228 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Jan. 20, 



and even these will be capable of correction by a more careful survey 

 of the facts. For the mathematical doctrine on which they proceed 

 is rigorously true, and does not depend upon any hypothetical view 

 of the structure of the masses which we have to deal with. Mr. Scott 

 Russell tells us that the wave of translation may be regarded as a 

 mechanical agent for the transmission of power, as complete and 

 perfect as the lever or the inclined plane. Assuming this property 

 of the wave of translation as a basis, I shall point out some of the re- 

 sults of its operation in the case now to be considered. 



It has been stated to the Geological Society, that, by supposing the 

 sudden elevation of a submarine district, there is no difficulty in ac- 

 counting for a current of twenty-five or thirty miles an hour at the 

 bottom of the sea, as a consequence of the "wave of translation." 

 In making this assertion, I think it has not been sufficiently considered 

 that what is thus called a " current," is really a transient motion for 

 each point of the bottom of the water. The great wave is solitary : 

 the fluid before and behind it is at rest ; and the particles move only 

 while the wave is passing over them. Therefore the effect of such a 

 wave upon loose materials immersed in the fluid would be only one of 

 two : — either it would carry a single mass along with it, giving to it 

 its own velocity, — or it would give a transient motion to a series of 

 masses in succession, as it passed over each, moving each but a small 

 distance. A single wave of translation cannot explain the situation of a 

 long line of masses each of which is moved through a great distance. 



If indeed we suppose a series of waves of translation each produced 

 by a sudden elevation, or by some other paroxysmal action, we may 

 obtain a greater efl^ect. In the operation of such a battery, each 

 shock would be transmitted through the water by means of the wave, 

 and would do its measured work ; and by accumulating such processes, 

 any amount of result may be mathematically accounted for. 



In whatever manner we frame the hypothesis in order to account for 

 the " Northern Drift," the same mathematical equality, between the 

 work done and the force exerted, will hold, as if the efl^ect had been 

 produced by any other mechanical power : — whether the waves be 

 one or many, great or small. And as the amount of the work done 

 in transporting the northern drift from its parent rocks (supposing 

 their place known) to its present position, may be calculated upon 

 assumed numerical bases, we may test the theory of the wave of trans- 

 lation, by thus calculating the amount of sudden elevation which it 

 necessarily supposes. The numbers which I shall assume may be 

 grossly erroneous ; but the result being attained, can easily be cor- 

 rected by altering it in proportion to the alteration which ought to be 

 made in any of the numerical elements. 



In the * Geology of Russia ' it is stated that the northern drift 

 occupies a space 2000 miles long and 400 to 800 miles wide. If all 

 the materials were derived from one centre, we might, as a general 

 approximate view, suppose the area to be circular, with a radius of 

 800 miles ; or rather, semicircular, the northern half being for the 

 most part cut ofl". But if we suppose this semicircle of 1600 miles 

 diameter to be extended to a length of 2000, by taking the Scandina- 



