ADDRESS. xlvii 



subjects connected in some measure with those which I have just mentioned. 

 One is from Prof. Stokes, ' On our knowledge of the Theory of vibratory 

 Motions of Bodies in general,' — the other from Prof. Willis, ' On Acoustics.' 



Our volume of Reports lately published contains a very complete account, 

 by Mr. Hunt, of the present state of our knowledge in regard to the chemical 

 effects of solar radiation. 



In the subject of Chemistry, I am not aware that any gi-eat step has been 

 made ; although there have been numerous small advances in establishing 

 chemical relations and in inventing chemical processes. 



The subject of Geology has always excited much interest in this Associa- 

 tion. It is a matter of congratulation that the Museum of Economic Geo- 

 logy is now established in a habitation as well as in a form which guarantee 

 its permanent and useful existence. Among subjects bordering on Practical 

 Geology, I may allude to the late inquiries respecting the supply of water 

 from the chalk and Bagshot sand districts as likely to give valuable information. 

 In Speculative Geology, the labours of European as well as American geo- 

 logists have been continued with their usual ardour, and there are now com- 

 paratively few parts of the world which have not been in some degree geolo- 

 gically examined. Far be it from me to pretend to assign with exactness 

 specific discoveries (in observation or in inference) to specific persons ; to 

 say precisely what has been done by Sedgwick, what by Murchison, what by 

 Lyeli, what by Verneuil, — or even to state with accuracy what discoveries in 

 the aggregate have been made by all. So far, however, as I can gather, the 

 principal step made (not in the last year but in the last few years) has been 

 of this kind. The line between the chalk group and the lowest tertiary or 

 Eocene group has been drawn principally by Sir R. Murchison with great 

 distinctness ; and this has been done rather by palaeontological criteria than 

 by reasonings from order of superposition, &c. A very great step has been 

 made in the classification of the geology of Asia Minor, with the aid of this 

 new light, by a foreign geologist, M. Tchihatchef, now present. In the 

 course of these investigations, attention has been drawn to the magnitude of 

 the disturbances exhibited in these comparatively modern beds, — and the 

 question has again been raised in the minds of geologists, whether these 

 disturbances can be referred to causes now in action. It would be wrong, 

 however, even in this hasty glance, to omit to notice the discovery of traces 

 of the tortoise in beds so low as the lowest Silurian rocks, affording (appa- 

 rently) evidence of the existence of this animal at a much earlier time than 

 had usually been ascribed to it. I should be sorry also to make no reference 

 to Sir C. Lyell's calculation of the time of formation of the delta of the Mis- 

 sissippi — or to Prof. J. Forbes's paper on the modern extinct volcanos of the 



