OF THE MAGNETIC NEEDLE. 



11 



As upwards of a year had elapsed since the preceding result had 

 been obtained, I thought it would be interesting to determine again this 

 element, in order to judge what might be the amount, and what the direc- 

 tion of the annual variation if any — -Table IV. contains the results of 

 this series of Observations, continued from the 23d May to the 9th June. 

 The Observations were made by the same person, with the same precau- 

 tions, and using the same instrument as in the preceding year ; and 

 therefore we may, I think, receive with every confidence the amount of 

 the variation which for fifteen months appears to be 17' Q" west, the 

 declination itself being east, and amounting to 2° 41' 16" for 1828, and 

 2** 24' 10" for 1829. If this rate should continue, we may soon expect the 

 needle to point due north at Calcutta, after which, I suppose, it will con- 

 tinue to move westward, so us to occasion a westerly declination. 



Observations of the Magnetic Declination made at the Observatory, Surveyor 



GeneraVs Office, Calcutta. 



TABLE IV. 



Date. 



Hour. 



Barometer. 



Attached 

 Thermometer. 



Detached 

 Tlierraoiueter. 



North End of 

 Needle. 



South End of 

 Needle. 



Mean. 



1829. 



H. 



M. 







Inches. 







o 















o 



1 



II 



May 23d 







25 



P. 



M. 



29-220 



95-8 



96-0 



2° 



07' 



40" 



2° 



08' 



30" 



2 



08 



05-0 





4 



43 







•708 



85-5 



85-0 



2 



08 



25 



2 



10 



15 



2 



09 



200 



24th 



9 



15 



A. 



M. 



•862 



88-8 



88-8 



2 



08 



40 



2 



12 



40 



2 



10 



40-0 









15 



P. 



M. 



•780 



92-8 



94-5 



2 



04 



25 



2 



11 



15 



2 



07 



500 



25th 



9 



25 



A. 



M. 



•770 



90 



90-6 



2 



oc 



40 



2 



10 



40 



2 



08 



40-0 









15 



P. 



M. 



•738 



93-8 



95-0 



2 



10 



05 



2 



10 



50 



2 



10 



27-5 





4 



30 







•C50 



950 



940 



2 



07 



40 



2 



12 



10 



2 



09 



55-0 



26th 



9 



05 



A. 



M. 



•740 



89-7 



90-3 



2 



12 



25 



2 



14 



45 



2 



13 



35-0 









30 



P. 



M. 



•G8G 



95-0 



96 



2 



07 



05 



2 



10 



45 



2 



03 



55-0 





4 



18 







•604 



935 



93-5 



2 



09 



30 



2 



14 



40 



2 



12 



05-0 



27th 



9 



35 



A. 



M. 



•704 



900 



90-0 



2 



11 



35 



2 



13 



25 



2 



12 



300 









25 



P. 



M. 



•636 



93-7 



94-0 



2 



07 



30 



2 



11 



15 



2 



09 



22-5 





4 



20 







•56'J 



94^4 



93-4 



2 



10 



10 



2 



13 



00 



2 



11 



35-0 



28th 



9 



14 



A. 



M. 



•592 



86-0 



87-0 



2 



09 



25 



2 



13 



20 



2 



ii 



22-5 









30 



P. 



M. 



•548 



97^0 



97-5 



2 



07 



10 



2 



08 



20 



2 



07 



45-0 





4 



05 







•530 



900 



900 



2 



11 



40 



2 



16 



10 



2 



13 



55-0 



