1839.] 



Observations on the direction^ ^S. 



221 



li. — Observations on the Direction and Intensity of the Terrestrial Mag- 

 netic Force in Southern India, made hij Thomas Glanville Taylor, 

 Esq. Astronomer to the Honourable East India Company, and John 

 Caldecott, Esq. Director of the Trivandruni Observatory. — Communi- 

 cated by the former Gentlema?i. 



As far back as the year 1831, at the suggestion of Professor KuptFer, 

 I had projected making a series of observations upon the magnetic dip 

 and intensity in India ; but having failed in procuring the necessary ap- 

 paratus here, and having been equally unfortunate in an application in 

 England, I was necessarily compelled, pro temp, to give up my inten- 

 tion. In the year 1837, having been favoured by Captain Moresby, of 

 the Indian Navy, with the loan of a dipping needle, which had been sup- 

 plied to him by the Geographical Society of Bombay, for the express 

 purpose of making observations upon the coast of India;* and having, 

 through the kindness of Captain Drinkwater Bethune, R. N., been 

 favoured with the temporary loan of two of the intensity needles, which 

 had been employed in the magnetic survey of Ireland ; I determined to 

 employ the former, and to construct some needles of the latter descrip- 

 tion, wherewith to undertake for India, a series of observations similar 

 to that so ably accomplished in Ireland. 



With regard to the plan of observation ; the lines of equal dip and in- 

 tensity in India being nearly parallels of latitude, it was evident that 

 the observations should be made in a line at right angles to these, or 

 along the coast ; accordingly I resolved on commencing at Ongole, in 

 lat, 15° 12' N., and proceeding at intervals of 20 or 30 miles along the 

 coast to Cape Comorin (the southern extremity of the Peninsula) ; and 

 from thence along the western coast to Goa. 



To have performed the whole of this by myself, would have taken up 

 more time than could be conveniently spared consistently with the pro- 

 secution of my astronomical duties; which determined me to invite the 

 assistance of individuals resident in India, to take a part in the observa- 

 tions. My application was not long in meeting with attention from 

 many in various parts of India ; but the aid of only one of these (J. Cal- 

 decott, Esq. of the Trivandrum Observatoryt) was available to an extent 

 which promised to be useful. Accordingly I lost no time in making 



* The Geographical Society of Bombay were pleased, subsequently, to allow me to re- 

 tain the needles so long as I found occasion for them. 



+ The Observatory at Trivandrum, having been very lately established, is perhaps at 

 present but little known, but the excellence of its arrangements, and the superiority of 

 the instruments which have been ordered, added to the indefatigable zeal of its superin- 

 tendent, cannot fail soon to render it an establishment of importance. 



