Vol. 69.] ANNIVERSARY ADDRESS 01' THE PRESIDENT. lxxxiii 



In these brief remarks on a wide subject I have been able to 

 mention only a few of the investigations on gravity which have 

 been made. My object has been to show that in tbe best-mapped 

 country in the world a great work remains to be done. The plat- 

 form which we bave had under consideration not only presents 

 undulations, but is composed of a variety of rocks varying in 

 specific gravity, for it includes ancient sediments, some lying hori- 

 zontally, some highly inclined, in parts cleaved, with metamorphic 

 and igneous masses in places. Haviug regard also to the insular 

 character of Great Britain and its situation upon the margin of 

 the Europeau Continent, we seem to be confronted with a region in 

 which a Gravity Survey is pre-eminently desirable. 



