PROCEEDINGS OF THE MEETING. XY 



in the law which regulates the time of high water, agreements 

 both with each other and with theory ; and has at the same 

 time brought into view some anomalies which will give a strong 

 impulse to the curiosity with which we shall examine the re- 

 cords of future observations at some of these places and at 

 many others. I may perhaps here take the hberty of mention- 

 ing my own attempts since our last Meeting, to contribute 

 something bearing on this department. It appeared to me that 

 our knowledge of one particular branch of this subject, the 

 motion of the tide-wave in all parts of the ocean, was in such a 

 condition, that by collecting and arranging our existing mate- 

 rials, we should probably be enabled to procure abundant and 

 valuable additions to them. This, therefore, I attempted to 

 do ; and I have embodied the result of this attempt in an 

 ' Essay towards a First Approximation to a Map of Cotidal 

 Lines,' which is now just printed in the Philosophical TransaC' 

 tions of the Royal Societtj. If the time of the Meeting allows, 

 I would willingly place before you the views at which we have 

 now arrived, and the direction of our labours which these 

 suggest. 



** In the case of the science of Tides, we have no doubt about 

 the general theory to which the phaenomena are to be referi-ed, 

 the law of universal gravitation ; though we still desiderate a 

 clear application of the theory to the details. In another sub- 

 ject which comes under our review, the science of Light, the 

 prominent point of interest is the selection of the general 

 theory. Sir David Brewster, the author of our Report on this 

 subject, has spoken of ' the two rival theories of light,' which 

 are, as you are aware, that which makes light to consist in 

 material particles emitted by a luminous body, and that which 

 makes it to consist in undulations propagated through a sta- 

 tionary ether. The rivalry of these theories, so far as they 

 can now be said to be rivals, has been by no means barren of 

 interest and instruction during the year which is just elapsed. 

 The discussions on the undulatory theory in our scientific 

 journals have been animated, and cannot, I think, be considered 

 as having left the subject where they found it. The claims of 

 the undulatory theory, it will be recollected, do not depend 

 only on its explaining the facts which it was originally intended 

 to explain ; but on this ; — that the suppositions adopted in 

 order to account for one set of facts, fall in most wonderfully 

 with the suppositions requisite to explain a class of facts en- 

 tirely different ; in the same manner as in the doctrine of gra- 

 vitation, the law of force which is derived from the revolutions 

 of the planets m their orbits, accounts for the apparently re- 



