1868.] 



President's Address. 



143 



land has increased to 137, of which 46, or exactly one-third, belong to it 

 in common with the* Miocene deposits of Europe. 



Four of these are found in our own Bovey Tracey beds, which have 

 been already described by Prof. Heer in the ' Philosophical Transactions.' 

 Among these is Sequoia Couttsice, the commonest tree in the British 

 locality. Accordingly the age of the Greenland deposits has been fixed 

 beyond a doubt as Lower Miocene. 



The collection itself is expected to arrive in London shortly, when a 

 complete series of the specimens will be deposited in the British Museum, 

 in accordance with the terms prescribed by the British Association and the 

 Government- Grant Committee of the Eoyal Society. 



The redaction of the great scientific work, the Magnetic Survey of the 

 South Polar Begions — commenced in 1839, under the auspices and at the 

 expense of Her Majesty's Government — has been completed in the present 

 year by the presentation to the Royal Society, and the publication in the 

 Philosophical Transactions, of Maps of the three Magnetic Elements in 

 Southern Parallels, commencing in 30° south, and extending far beyond 

 the limits of ordinary navigation. These Maps are accompanied by Tables 

 containing the numerical coefficients to be employed in a revision of 

 ' Gauss's General Theory,' at the intersection of every fifth degree of lati- 

 tude and every tenth degree of longitude, between 30° south latitude and 

 the south terrestrial pole. The magnetical determinations of the Survey 

 correspond to the epoch 1842^. Similar Maps for the corresponding 

 latitudes of the Northern Hemisphere, from 30° north latitude to the north 

 terrestrial pole, are in preparation, founded on a coordination of results 

 obtained by magneticians of all countries in the fifteen years preceding 

 and the fifteen years following the same mean epoch of 1842|, and reduced 

 to it. It is hoped that these Maps, with an accompanying Memoir, will 

 be presented to the Eoyal Society before the close of the present session. 

 There will then remain for subsequent completion the filling up (still for 

 the same epoch) of the space between the parallels of 30° north and 30° 

 south latitude, for which much preparation has been made in the assem- 

 blage of materials, requiring only, for their coordination, the allotment of 

 the time needed for the due examination and treatment of so large a body 

 of materials. Should I be so happy as to be able to complete this task also, 

 (my occupation in Terrestrial Magnetism has now extended, more or less, 

 over half a century,) I venture to express a hope that the great work of 

 which the foundation will thus have been laid, viz. " the Revision of the 

 Gaussian Theory, corresponding to a definite epoch in the great cycle of 

 terrestrial magnetism," may, when a suitable time shall appear to have 

 arrived, be taken up and completed under the auspices of the Royal 

 Society. 



Whilst on the subject of Terrestrial Magnetism, I may remark that, in 

 a recent number of his ' Wochenberichte,' Dr. Lamont has called the 



