432 Proceedings of the British Association. 



ences caused the tides ; but still we had not traced through all the de- 

 tails of mechanical causation the mode in which these influences produce 

 the various phenomena these tides presented. Laplace, the greatest ma- 

 thematician of his age, had been unequal to the task of these complicated 

 calculations. He could not avoid mentioning, in connexion with this 

 subject, the paper read by Mr Russell, in the Physical section. Mr Rus- 

 sell had successfully investigated the laws regulating the propagation of 

 waves, and had shewn the relation between the velocity with which the 

 wave travels along, and the depth of the water, no matter how long the 

 canal, even were it as long as the Atlantic. Thus, could we ascertain 

 the depth of the Atlantic, w r e should know the rate of the tide. But 

 might we not reverse the process, and ascertain the depth from the tide ? 

 Here there was another instance of the relation of all the sciences, and 

 geology would be indebted for this important knowledge to mathematical 

 and physical investigation ; nay more (continued the learned Professor), 

 when the British Association shall meet, 200 years hence, perhaps in this 

 very room — for meet at that period I am convinced it will — the individual 

 who shall then occupy the position which I do now shall turn to the 

 geologist, and telling him the rate of the tide — a rate, perhaps, very dif- 

 ferent from that at which it travels now — will calculate for him the depths 

 of the ocean ; and thus the geologist shall know, with accuracy, the se- 

 crets of those depths where no plummet ever sounded, and no line was 

 ever cast, explored by the power of this liquid lever, which the investi- 

 gations of physical science had placed in his hand ; and when they look 

 back to our proceedings at this period, they will, I hope, in returning to 

 next year's meeting, be able to calculate the depths of the ocean back for 

 two hundred years, and thus ascertain for that period the geological 

 changes in the fathomless caverns of the great deep. 



Thursday. — An elegant dejeune was given by the College of 

 Physicians. In the afternoon the Lord Lieutenant entertained 

 at dinner a select party of distinguished scientific individuals. 

 In the evening, in the Rot undo, there was a gay and interest- 

 ing promenade, with delightful music, and all the other agree- 

 able excitements of meetings without formality and without 

 pretension. This deviation from the usual practice of the 

 British Association was universally applauded. Indeed, we 

 cannot help thinking that it would be an improvement, if there 



was less lecturing and more amusement after the sectional busi- 

 es 



ness. 



Friday. — This morning a splendid dejeune was given at the 

 Botanic Gardens at Grlasnevin. In the Rotundo, in the even- 

 ing, the Presidents of the different Sections gave an account 

 of tlie various papers read during Thursday and Friday's meet- 

 ings — Professor Babbage then offered some suggestions as to 

 determining the age of peat-mosses by the annular layers of 

 the trees found in them. If, for instance, there be two broad 

 rings separated by a narrow one, it would shew that at some 

 period two years of favourable growth had been divided by 



