MAGNETIC SURVEY OF PENNSYLVANIA. 



(INCLUDING PART OF OHIO AND NEW YORK.) 



SECOND MAGNETIC TOUR OF 1841. 



Date. 



April 26 



Abstract of Relative Intensity and Dip at '20 Stations. 



Girard College, Philadelphia. 



Sky covered, light fleecy, cirro-stratus, and cirrus. 



Time. 



4'' P. M. 



Needle. 



X". 1 

 No. 3 



Dip. 



72° oo'. 4 



7 2 00.4 



Temp. Fain-. 



G8° 



68 



Dip when loaded. 



18° 06'.7 

 13 55.9' 



Dip reduced. 



72° 01'. 1 

 72 10.1 



Relative total 



iuteuMty. 



Mean 



71 01.1 1.1778 



N. B. Needle No. 1, new or pin weight in last hole of end B. 



" No. 3, " " hole nearest to end B. 



1.1778 

 1.111.") 



July 20 



Philadelphia. 



Needle. 



C\ Under 

 Bar 



Temp. Fahr. 



75°.8 

 70.1 



No. of 

 vibrations. 



Time of 

 }u vibrations. 



500 

 500 



.",1 7 70 

 36.1118 



Corr'd. 



34". 741 

 36.836 



Clear. 



Horizontal 

 intensity. 



L.0000 



1.0000 



' This observation is defective, should he about 20O. The reeord says L. Needle, No. 2, but no buoIi Lloyd 

 needle is used elsewhere. 



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