584 



December 16, 1858. 

 SIR BENJAMIN C. BRODIE, Bart., President, in the Chair. 



In accordance with notice given at the last Meeting, the Right 

 Rev. the Lord Bishop of Ripon was proposed for election and im- 

 mediate ballot. 



The ballot having been taken, his Lordship was declared duly 

 elected. 



The following communications were read : 



I. Extract of a Letter from Professor LAMONT to Major-Gene- 

 ral SABINE, Treas. and V.P.R.S., dated Munich, Dec. 19, 

 1858. Communicated by Professor W. H. MILLER, For. 

 Sec. R.S. 



"My magnetic observations in France, Spain, and Portugal are 

 now published, and a copy for you is on the way. The observations 

 of last summer are under the press. They comprehend about thirty 

 stations in the North of Germany, Belgium, Holland, and Denmark. 

 Next year I am going to Italy, and in 1860 I intend to revisit 

 Spain, in order to observe the total eclipse of the sun, and also 

 to make magnetic observations. 



" I have found that on the Continent the lines of horizontal intensity 

 move from south-west to north-east, making an angle of about 20 with 

 the meridian, that is, in a direction coinciding with the lines of de- 

 clination. The lines of inclination seem to move in the same direc- 

 tion, and the motion of the lines of declination will probably coincide 

 with the lines of horizontal intensity. Calling + AH and At the 

 annual changes of horizontal intensity and inclination of a central 

 station (suppose London), the annual changes for a place situated x 

 degrees in latitude to the north, and y degrees in longitude to the 

 west, will be 



AH O'OOO ISx +0-00008y (absolute measure, French units), 

 -A^ +0'-21a? -0 N 09y. 



" The new survey of the British Islands will offer an opportunity of 

 testing the correctness of these formulae." 



