iro 



thor of the most important discoveries or series of investigations 

 sufficiently established or completed to the satisfaction of the Council 

 within the last five years, and for which no honorary reward had 

 been previously received. The Council of the Royal Society, pre- 

 mising that they decline to express any opinion on the controverted 

 positions contained in Mr.Lyell's work, entitled " Principles of Geo- 

 logy," state the following as the grounds of their award. 



1. The comprehensive view which the author has taken of his 

 subject, and the philosophical spirit and dignity with which he has 

 treated it. 



2. The important service he has rendered to science by especially 

 directing the attention of geologists to effects produced by existing 

 causes. 



3. His admirable description of many tertiary deposits, several 

 of these descriptions being drawn from original observations. 



Lastly, The new mode of investigating tertiary deposits, which his 

 labours have greatly contributed to introduce; namely, that of de- 

 termining the relative proportions of extinct and still existing spe- 

 cies, with a view to discover the relative ages of distant and uncon- 

 nected tertiary deposits. 



Of the Work so honoured by the Royal Society, the third edition 

 has been lately published : in this edition some opinions formerly 

 expressed have been modified or renounced, and much new matter 

 has been introduced ; the phaenomena of springs and Artesian wells 

 have been more fully treated ; the theory of elevation has been en- 

 tered into more at large, the author still controverting that theory. 

 A chapter, almost entirely new, points out the probable causes of 

 volcanic heat ; objections are advanced against the doctrine of the 

 central fluidity of the earth, and especially the intense heat attri- 

 buted by some writers to the internal nucleus, Mr. Lyell considers 

 how far chemical processes in the interior of the earth may generate 

 volcanic heat, and what may be the effect exerted by currents of 

 electricity. Sir Humphry Davy's theory of an unoxidated metal- 

 lic nucleus is considered, and it is suggested that compounds re- 

 sulting from the action of water upon metallic bases may be again 

 deoxidated by the hydrogen set free in that process. The author 

 has also given a more complete view of his opinions respecting the 

 origin of caverns, and the manner in which they have been filled 

 with breccia and the bones of animals. In illustrating this sub- 

 ject, he refers particularly to the recent discoveries of MM. Virlet 

 and Boblaye in the Morea. His sketch of the principal secondary 

 formations is also considerably enlarged. 



Two other publications have issued from the press during the 

 last year, which are eminently deserving of your attention. The 

 first of these, entitled " A Treatise on Primary Geology," originated 

 in great measure from a discussion that took place at a Meeting of 

 the Geological Section of the British Association at Cambridge, and 

 was drawn up with a view to the further consideration of the chief 

 questions which it embraces, at the subsequent Meeting of the same 

 body at Edinburgh. 



