MAGNETIC DIP IN THE UNITED STATES. 



301 



Magnetic Dip at St. Louis, Missouri. Latitude 38° 38' N.; Longitude 90° 4' W. 

 Place of observation one mile west of the city. 



Date. 



Hour. 





Needle. 



No. 



Readings. 





Dip. 



, Sept. 29, 



9—11, A. 



M. 



No. 1, 





40 



69^ 



' 31'.5 





(( 





No. 1, poles reversed, 





40 





20.8 





(< 





Mean of No. 1, 





80 





26.1 





(( 





No. 2, 





40 





16.5 





(( 





No. 2, poles reversed, 





40 





33,2 





C( 





Mean of No. 2, 





80 





24.9 





(< 





Mean of both needles. 





160 



69 



25.5 



Magnetic Dip at Vincennes, Indiana. Latitude 38° 43' iV.; Longitude 87° 29' TV. 



Place of observation a half mile above the lower ferry, near the bank of the 

 river. 



Date. 



Hour. 



Needle. 



No. 



Readings. 



Dip. 



1841, Oct. 1, 



10—12, M. 



No. 1, 





40 



69° 45'.9 



«( 



(( 



No. 1, poles reversed, 





40 



55.0 



i( 



<( 



Mean of No. 1, 





80 



50.4 



(C 



(C 



No. 2, 





40 



63.1 



« 



(( 



No. 2, poles reversed. 





40 



43.4 



i( 



i( 



Mean of No. 2, 





80 



53.3 



<( 



(( 



Mean of both needles. 





160 



69 51 .9 





Observations repeated three rods north-east of the last Station. 





Date. 



Hour. 



Needle. 



No 



. Readings. 



Dip. 



1841, Oct. 1, 



1—3, P. M. 



No. 1, 





40 



69° 55'.6 



<( 



t( 



No. 1, poles reversed, 





40 



47.1 



<( 



(( 



Mean of No. 1, 





80 



51 .3 



(( 



(( 



No. 2, 





40 



43.7 



(( 



(C 



No. 2, poles reversed. 





40 



68.5 



<( 



(( 



Mean of No. 2, 





80 



56.1 



(( 



(( 



Mean of both needles. 





160 



69 53.7 



Mean of 320 i 



•eadings of both needles, 



• • • • 



, 



. 



69 52.8 



Magnetic Dip at Cincinnati, Ohio. Latitude 39° 6' N.; Longitude 84° 27' TV. 

 Place of observation, Mr. Longworth's garden, on the east side of the city. 



Date. 



Hour. 



Needle. 



No. Read 



ngs. 



Dip. 



, Oct. 5, 



10—12, M. 



No. 1, 



40 





70° 19'.2 



<( 



(( 



No. 1, poles reversed, 



40 





35.9 



(( 



(C 



Mean of No. 1, 



80 





27.5 



