16 



M A G X E T I C SURVEY OF P E N X S V h V A N I A . 



Girard College, Philadelphia. — Magnetic observatory, on stand near marble pillar where 

 dip is observed. 



Date. 



Oct. 9 



— P. M. 



— P. M. 



Xo. 1 

 No. -2 



Mean 



Dip. 



71° 57'.9 

 71 58.2 



71 58.0 



Date. 



Needle. Temp. Fahr. No. of series. 



Nov. 1 ,4" 15"' P.M. Cylinder 



" " " | Par 



C3°.5 

 G3.0 



No. of 

 vibrations. 



500 

 400 



Time of 

 10 violations, 



34".86 

 36.92 



Cun'.l. 



34'.854 

 36.907 



Horizontal 

 ■Dtenttity. 



1.0000 



1.0000 



