AMERICAN 



JOURNAL OF SCIENCE AND ARTS. 



[THIRD SERIES.] 



) the Variation of the Magnetic Decli- 

 with the Aurora of October 14, 1870. 

 With remarhs on the physical connection between changes in 

 area of disturbed solar surface and magnetic perturbations ; by 

 Alfred M. Mayer, PLD. 



The aurora of October 14th was first observed by me at 6i» 

 SO" p. M. as a ruddy glow in the N.N.E., reaching to about 40° 

 above the horizon. The magnetic observations were commenced 

 at eb B5^. In the following table the first column contains the 

 times of observation in Bethlehem mean time (long. E. Washing- 

 ton e-n 42^ lat N. 40° 36' 24"), while in the second are given the 

 declinations, + indicating a W. and — an E. movement of the 

 N. end of the magnet in reference to the line of mean declina- 

 tion of the day, taken as the mean of the maximum E. elonga- 

 tion at 8^ SO'^ and the maximum W. elongation at 13*" 17"". 

 This line of mean declination we will call 0°. 



50 +1 

 56 +1, 



