374 



Observations of the Magnetic 



[May, 



VI. — Observations of the Magnetic Dip and Intensity at Madras. By 

 T. G. Taylor, Esq. H. C. Astronomer. 



Notwithstanding- the value which has of late years been attached to 

 observations of the Magnetic Dip and Intensity, 1 may, I believe, safely 

 state, that the whole of British India has failed to put on record a 

 single good set of experiments to this end. With a view to supply 

 this deficiency for Madras, I have availed myself of the loan of a very 

 excellent dipping needle, the property of Captain Drinkwater, of 

 His Majesty's ship Conway ,• and of two magnetic intensity needles 

 which were brought out by the same officer, and are the property of 

 Captain James Clarke Ross, R. N. The dipping needle, which was 

 constructed on purpose for the Conioay, differs, I believe, in no respect 

 from the ordinary construction, save that it is one of the best instru- 

 ments I have met with, and, as far as I can see, absolutely faultless. 

 The observations for Dip are as follows. 



Observations for Dip made at the Madras Observatory, situated in Long. 

 5h. 21m. 7s. 8 East of Greenwich, and Lat. 13° 4' 8". 8 N. on the 

 26th April, 1837. 



With Needle marked No. 1. 



Face of Instrument E 2st. 

 No. A. B. No. 



1 7° 26' 7° 28' 2 



3 7 6 7 4 4 



5 Inverted the axis, 7 24 7 17 6 



7 7 30 7 24 8 



9 

 11 

 13 

 15 



Reversed the Poles. 

 7 28 7 22 10 



7 12 7 7 12 



7 16 7 24 14 



7 26 7 23 91 



A. 



6» 16' 

 6 12 

 6 4 

 6 16 



6 34 

 6 16 



B. 



6° 14' 

 6 8 

 6 8 

 6 



24 



27 



22 



6 38 



6 21 



6 28 



6 33 



Mean, 7" 21' 0" 7° 18' 37" 



Needle marked No. 2. 

 1 7 31 7 20 2 



3 7 31 7 42 4 



5 Inverted the axis, 7 42 7 25 6 



7 7 50 7 30 8 



Reversed the Poles. 

 24 7 6 2 



26 7 4 4 



34 6 44 6 



6° 18' 37" 6° 21' 30" 



9 

 11 

 13 

 15 



7 

 7 

 6 

 6 34 6 43 



8 



2 



8 



55 



45 





 10 

 15 

 23 



38 

 58 

 14 

 55 



21 



28 







4 



Mean, 7 19 7 11 45 6 34 45 



And taking the general mean, we get the true Dip 



with Needle No. 1 6 49 56 No. 



ditto ditto „ 2 6 55 4 



6 34 45 



Mean, 6 52 30 



