Proceedings of the British Association. 549 



cuous in many places, and appears to confirm the view of the separate 

 transmission of concurrent waves presented by Mr. Scott Russell, 

 but that this doctrine is still somewhat meagre ; and though it appears 

 to account for the phenomena in the present case, must be considered 

 as short of absolute certainty. — Mr. Holden observed that we have 

 on the west coast in Lancashire, a mile to the north of Southport, 

 a secondary tide, in fine calm weather. The tide comes to the height, 

 and then retires a good way, and in fifteen minutes returns to the same 

 height again. This secondary tide is that which comes round Treland, 

 and, passing through the Mull of Galloway, comes a little later to 

 our coast. — In reply, Mr. Scott Russell stated, that he perfectly agreed 

 with Mr. Whewell in thinking that it was desirable to have the subject 

 ascertained by a still more extensive series of experiments, and that 

 observations were now actually in progress with that view. — The Rev. 

 Dr. Scoresby had frequently at sea seen several courses of waves, each 

 pursuing its own track undeviatingly, although crossing the track of 

 others at various angles. At the places where the crests of one series of 

 waves crossed the crests of the waves of another series, there knots 

 were formed, and it was this circumstance which the sailor dreaded ; for 

 if the wind blew ever so violent from one fixed quarter, it only raised 

 one series of parallel waves, and these, however lofty, were never 

 dreaded by the sailors; but when the wind, after blowing violently 

 from one point, shifted suddenly a few points, a new series of parallel 

 waves was generated, crossing the former series, and at the knots 

 the waves accumulated the one on the other, while the trough of each 

 deepened the trough of the other between every four knots ; hence the 

 forms of the waves also were so much deranged that the crests top- 

 ped over, and breakers were formed. These cross seas were what 

 the sailor had chiefly to dread. — Mr. Russell said that the waves of 

 which Dr. Scoresby spoke were the oscillating waves of the sea ; these 

 were quite unlike waves of translation, of which alone he had been 

 speaking, both in their structure and in the laws which they observed. — 

 The President remarked, that if Mr. Russell established the fact, which 

 he had now so ably brought before the Section, of the separate indivi- 

 duality, even when they had blended, of different waves of translation, 

 so that they were capable of again separating under their proper condi- 

 tions, he conceived that he had added a new and important fact to 

 those previously established on the subject. 



Mr. Dent reported ' On his Chronometrical experiment to determine 

 the difference of Meridians between Greenwich and Devonport.' — The 

 following are the results : — 



