272 



Terrestrial Maqncdc Forcr in SouiJicrn India. 



[AriUL 



we get fioni cylinder No. 3 \ ; // = 2.1/4 

 and No. 3 //' =z 2.225— 



whereas, from the somewhat probable miinbers we have just assumed, 



cylinder No. 3 X gives h, = 2.268 

 No. 3 _ // — 2.2G4 



The latter numbers, if admitted, now remain to be diminished in the 

 proportion of 1.0098 to 1.0000 for the local influence at Madras; when, 

 with reference to the formula at p;>ge 2G9, we get 



Horizontal Intensity. Total Intensity. 



in London. 1 1 



Magnetic Equator ^ 2.259 

 Longitude /9" E. \ 



,80G5 



In conclusion, I cannot but feel regret that I have devoted so much 

 space to the discussion of observations, which in the end have furnished 

 results of but comparatively little importance; but, viewing these ob- 

 servations as a part only of a series, which will probably ere long be ex- 

 tended to the most northern limits of India, and perhaps some parts of 

 Persia, it becomes a question, whether, on the whole, they are not just 

 what could be desired. ^ 



Madras Observatory,) 

 9th March, 1839. S 



