296 Geological Society. 



positions have been confirmed in a manner which the inventor could 

 not have foreseen. 



The most striking modern support of these correcter views, is due 

 to Von Buch and Humboldt, and to the facts and inferences derived 

 by Dr. MacCulloch from the country which gave birth to Hutton, 

 and to his illustrator, Mr. Playfair, and in which were made the expe- 

 riments of Sir James Hall. More recently, a series of facts observed 

 by Professor Henslow, in the Isle of Anglesea*, has proved, in the most 

 satisfactory manner, the connection of veins of trap with very high tem- 

 perature 5 since the change produced upon the strata, through which 

 the substances now occupying the veins were injected, has approached 

 so nearly to fluidity, as to admit of their crystallization, in forms differ- 

 ent from any which the components of the rocks, if they had not been 

 thus acted on, would have afforded. Sir Humphry Davy's experiments 

 on the fluids contained within cavities in crystals f, are another strik- 

 ing and unexpected confirmation of Hutton's views : and our own 

 Transactions, besides various incidental pieces of evidence derived 

 from this country, supply the testimony of an unprejudiced witness to 

 an earthquake on the coast of Chili J, which brings almost before the 

 eyes of the reader, the movement and permanent elevation of the land. 



Having alluded to Mr. Playfair's support of the volcanic theory, it 

 would be unjust to the memory of that distinguished man, not to 

 mention, that his geological writings have had, indirectly, an effect in 

 accelerating the progress of our subject, the benefit of which we expe- 

 rience at this moment, and probably shall long continue to feel j and 

 which, perhaps, outweighs in value the partial success of the specula- 

 tions for which he so strenuously contended. He clothed our sub- 

 ject with the dignity of an eloquence most happily adapted to phi- 

 losophic inquiry, and redeemed the geologist from association with 

 that class of naturalists who lose sight of general laws, and are 

 occupied incessantly with details j — placing him, where he ought 

 to stand, beside the mathematician, the astronomer, and the che- 

 mist -, and permanently raising our science into an elevated depart- 

 ment of inductive inquiry. His mild and tolerant character threw an 

 assuaging influence upon the waves of a controversy, which in his 

 time considerations entirely foreign to science had exasperated into 

 unusual violence : and if, fortunately, there is no longer any trace of 

 this asperity, the change must, in a great degree, be ascribed to the 

 tone of Mr. Playfair's writings, enforced by the manly and consistent 

 tenour of his blameless life. 



I cannot, for your sake, regret that the presence of some of those 

 who have had a large share in the foundation of this Institution, pro- 

 hibits my alluding to their continued and unremitting efforts in sup- 

 port of it. — And the same cause prevents my dwelling on the effects 

 produced, at both our Universities, by the geological instructions de- 

 livered there ; which have given to the subject an impulse perhaps 



* Transactions of the Cambridge Philosophical Society, vol. i. page 406. 



f Philosophical Transactions, 1822, page 367, &c. 



j Geological Transactions, second series, vol. i. page 413. 



without 



