MAGNETIC DIPS IN THE UNITED STATES. 



107 



Magnetic Dip at Worcester, Massachusetts. Latitude 42° 16' N.; Longitude ih. 47m. W. 

 Place of observation a few rods west of Worcester House. 



Date. 





Hour. 



Needle. 



No 



Readings. 





Dip. 



1839, Sept. 



16th, 



4—6, P. M. 



No. 1, 





40 





74c 



' 19'. 6 









No. 1, poles reversed, 





40 







26.0 









Mean of No. 1, 





80 







22.8 









No. 2, 





40 







11 .1 









No. 2, poles reversed. 





40 







25.5 









Mean of No. 2, 





80 







18 .3 









Mean of both needles, 





160 





74 



20 .6 



Magnetic Dip at Cambridge, Massachusetts. Latitude 42° 22' N.; Longitude 4h. iim. W. 

 Place of observation a few rods south-west of the colleges. 



Date. 





Hour. 



Needle. 



No 



Read 



ngs. 





Dip. 



1839, Sept. 



17th, 



3—5, P. M. 



No. 1, 





40 





74 



= 19'.2 



ii t( 







No. 1, poles reversed, 





40 







18.9 



(( (( 







Mean of No. 1, 





80 







19.1 



U (( 







No. 2, 





40 







19.4 



ii £C 







No. 2, poles reversed, 





40 







22.7 



(( ii 







Mean of No. 2, 





80 







21 .0 



(( U 







Mean of both needles, 





160 





74 



20.1 



Magnetic Dip at Providence, Rhode Island. Latitude 41° 50' N.; Longitude 4h. 46m. W. 

 Place of observation near the steam-boat landing. 



Date. Hour. Needle. No. Readings. Dip. 



1839, Sept. 19th, 111, A.M.— 1, P.M. No. 1, 40 ° 73° 57'.0 



No. 1, poles reversed, 40 60 .6 



Mean of No. 1, 80 58 .8 



No. 2, 40 62 .8 



No. 2, poles reversed, 40 57 .9 



Mean of No. 2, 80 60 .3 



Mean of both needles, 160 73 59.6 





