% INCLINATION AND DECLINATION 



Memorandum of Observations made at the Observatory/, Surveyor GeneraVs 

 Office, Chowrmghee, Calcutta, to determine the Magnetic Declination between 

 the 3d Februaiy and 24th February, 1828. 



" The Declination instrument is made by Gilbert ; the azimuth circle 

 is of eight inches diameter, and divided to 30' subdividing to single minutes ; 

 the divisions are read by three verniers, at equal distances, and each 

 observation below noted is the result of twelve readings ; i. e., three with 

 the face of the altitude circle to the east, and three to the west, from the 

 north end of the needle, and of as many from the south end. The telescope 

 is of llf inches focal length, and If inch aperture, and carries cross wires. 



The instrument being placed on a stone pillar at a convenient dis- 

 tance from the transit instrument in the Observatory, out of the influence 

 of iron, and duly adjusted, was correctly laid on the distant meridian 

 mark by causing its centre wire to cover the distant meridian mark, and 

 also the centre wires in the transit telescope, the wiie of the declination 

 instrument being reciprocally viewed and covered by the meridian wire 

 of the transit telescope." 



The result derived from three Needles, are as follow : 



TABLE II. 



Date. 

 1828, 



Time. 



Barometer 

 by 



Troughton. 



o 



"5 § 

 H 



Detached 

 Thermometer. 



Declination 

 East of tlie 

 North end of 

 the Needle. 



Declination 

 West of tlie 

 Soutli end of 

 the Needle. 



Mean Declination East. 



February 



3 



H. M. 



40 p. M. 

 05 30 p. M. 



Inches. 







2° 35' 50" 

 2 22 00 



2° 27' 30" 

 2 23 50 







4 



09 20 A. M. 



29-960 



67° 



70° 



2 25 40 



2 28 50 









00 35 p. M. 



29930 



78 



79 



2 24 00 



2 26 20 









5 15 P. M. 



29'864 



80 



82 



2 22 10 



2 21 20 







5 



8 55 A. M. 



299C2 



69 



70 



2 27 50 



2 28 30 









25 p. M. 



29-954 



77-7 



80 



2 24 50 



2 23 40 









5 25 P. M. 



29-888 



80 



82 



2 22 00 



2 28 30 





