MAGNETICAL OBSERVATIONS IN SCOTLAND. 



109 



dip, and corrected for the variations of temperature inserted in 

 the preceding columns. In the first of the final columns the 

 ratios are expressed to unity in Dvihlin. In the last column the 

 ratios are expressed to unity in London, and are the numbers in 

 the preceding column multiplied by 1*0208, which has been 

 ascertained by Mr. Lloyd to express the value of the intensity in 

 Dublin, that at London being unity. {Trans. R. I. Academy, 

 1836.) 



Table IV. 



Intensity, Needle S (2). 



If now we make/= the most probable value of the intensity 

 at the same central geographical position that was assumed in 

 the calculation of the dip observations, viz. lat. 56° 27', long. 

 4° 25' west ; u = the angle which the isodynamic line pass- 

 ing thi'ough the central position makes with the meridian ; 



