Evening Meeting, 349 



feet above the sea level ; and this valley could not have been scooped 



out Dr Buckland was of opinion that the land must have been 



dry before the action of the water that had transported these blocks. 

 There was a great number of organic remains mixed with the 

 gravel, derived from animals existing on dry land ; and this was 

 not only true in England, but confirmed by observations made on 

 the continent of Europe. 



In the Statistical Section Dr Lai'dner delivered a lecture on Steam 

 Communication with India. 



In the Section of Mechanical Science, Mr Whewell gave a short 

 account of the present state of the science of the Tides. Though 

 there can be no doubt, that the tides are to be reckoned among the 

 results of the great law of universal gravitation, they differ from all 

 the other results of that law in this respect, that the facts have not, 

 in their detailsj been reduced to an accordance with the theory ; and 

 the peculiar interest of the subject at the present moment arises 

 from this, that the researches now going on appear to be tending 

 to an accordance of theory and observation ; although much in the 

 way of calculation and observation remains to be still effected before 

 this accordance reaches its ultimate state of completeness. With 

 regard to observation, the port of Bristol offers peculiar ad- 

 vantages ; for, in consequence of the great magnitude of the tides 

 there, almost all the peculiarities of the phenomena are m«igni- 

 fied, and may be studied as if under a microscope. With regard to 

 the theory, one point mainly was dwelt upon. By the theory, the 

 tides follow the moon's southings at a certain interval of time, (the 

 lunitidal interval,) and this mean interval will undergo changes, so 

 as to leave less than the mean when the moon passes three hours 

 after the sun, equal to the mean when the moon passes six hours 

 after the sun, and greater than the mean when the moon passes nine 

 hours after the sun ; and the quantity by which the lunitidal interval 

 is less than the mean when the moon is three hours after the sun, is 

 exactly equal to the quantity by which the lunitidal interval is 

 greater than the mean when the moon passes nine hours after the 

 sun. And this equality of the defect and excess of the interval at 

 three hours and at nine hours of the moon's transit, is still true 

 where the moon's force alters by the alteration of her parallax or 

 declination. Now we are to inquire whether this equality of ex- 

 cess and defect of the interval in all changes of declination, &c is 

 exhibited by observation. It appears at first sight, that the equality 

 does not exist ; that is, if we obtain the lunitidal interval by com* 



VOL, XXI. NO. Xm. — OCTOBER 1836. A a 



