MAGNETIC DECLINATION NEAR THE MAGNETIC EQUATOR. 



681 



which the law changes with the latitude in each month of the year. For this 

 purpose it will be preferable to reduce the movements of the horizontal needle to 

 those of the needle freely suspended in the direction of the magnetic inclination, 

 since the latter become greatly exaggerated in high latitudes when observed in 

 the more commodious suspension of the horizontal needle. 



Stations. 

 Ten stations have been chosen for this investigation. The following table 

 contains the facts required concerning them : — 



Table III. — Data relating to the Stations and Observations of Magnetic Declination 



considered in this Paper. 



Station. 





















Latitude. 



Longitude. 



Height 



above Sea. 



Magnetic 

 Inclination. 



Tears of 

 Observation. 



Directors of the 

 Observatories. 







No. 



Name. 

























. 



h m 



Feet. 



c 









1 



Makerstoun, 



55 



35 N. 



10W. 



213 



71 



30'N. 



1843-46. 



r 



Mr J. A. Broun. 

 Lieutenant Riddell,RA., 



2 



Toronto, . 



43 



40 N. 



5 17 W. 





75 



15 N. 



1842-48.) 



1 



{ 



Lieutenant Lefroy, 

 R.A., and Lieutenant 

 Younghusband, R.A. 



3 



Simla, . 



31 



6N. 



5 9 E. 



8000? 



41 



40 N. 



1842-44. 



Major-General Boileau. 



4 



Bombay, . 



18 



56 N. 



4 51 E. 



A few feet. 



18 



44 N. 



(1851-55. j 

 (1857-61. 1 



( 



Captains Montriou and 

 Eerguson of the Indian 

 Navy. 



MrT. G.Taylor, Colonel 



5 



Madras, . 



13 



4N. 



5 21 E. 



A few feet. 



7 



40 N. 



1846-50. -j 



Worster, and Captain 

 Jacob. 



6 



Trevandrum, 



8 



31 N. 



5 8 E. 



200 



2 



30 S. 



1853-64. 



Mr J. A. Broun. 



7 



Singapore, 



1 



19 N. 



6 56 E. 



A few feet. 



12 



40 S. 



1841-45. 

 [ 



Captain C. M. Elliot. 

 Lieutenant Lefroy, R. A., 



8 



St Helena, 



15 



57 S. 



23 W. 



1760 



22 



s. 



1842-47. 



and Lieutenant 

 Smythe, R.A. 



9 



(Cape of Good) 

 ( Hope, . ) 



33 



56 S. 



1 14 E. 



A few feet. 



53 



20 S. 



1841-46.1 



Lieutenant EardleyWil- 

 mot, R.A. 



10 



Hobarton, 



42 



53 S. 



9 50 E. 



105 70 



20 S. 



1843-48. 



Commander Kay, R.N. 



1. Transactions of the Royal Society of Edinburgh, Vols. XVII. XVIII. XIX. 



2. 8, 9, 10. Observations at the Colonial Observatoi'ies, published under the superintendence of 

 Major General Sabine. 



3. Simla Observations. Copy of Abstracts issued from the Simla Observatory. 



4. Bombay Observations, printed at" Bombay by order of Government. 



5. Madras Observations, printed at Madras by order of Government. 



6. Observations, unpublished. 



7. Singapore Observations, printed by order of Government. 



It will be perceived that five of the stations have north magnetic latitude, 

 and five south magnetic latitude, while their distribution varies in longitude 

 betwixt 5 h 17 m W. and 9 h 50 m E. The means are not derived from observations 

 in the same years, nor from the same number of years' observations, and they 

 are not therefore strictly comparable. It is conceived, however, that in each 



VOL. XXIV. PART III. 8 Y 



