4 ABBE — THE ALTITUDE OF THE AURORA. [Jan. 7, 



Treasurer. 



Horace Jayne. 



Councillors for three years. 



Henry C. Baird, Isaac J. Wistar, Jacob M. DaCosta. 



Councillor for one year^ to fill an unexpired term. 



Georsje F. Edmunds. 



Dr. I. Minis Hajs was nominated for Librarian for tlie 



ensuing year. 



Prof. Cleveland Abbe read a paper on " The Accepted 

 Altitude of the Aurora Borealis." 



Mr. Sachse and Mr. Cook offered some remarks in dis- 

 cussion. 



Dr. T. J. J. See presented a paper for the Transactions on 

 " The Evolution of the Stellar Systems," which was dis- 

 cussed by Prof. Doolittle, Prof. Sn3^der, Dr. See and Prof. 

 Abbe. 



The Society was adjourned by the presiding member. 



THE ALTITUDE OF THE AURORA ABOVE THE 



EARTH'S SURFACE. 



BY CLEVELAND ABBE. 



(Mead January 7, 1S9S. ) 



During the past three centuries numerous observers and physicists, 

 astronomers and magneticians have endeavored to contribute to our 

 knowledge of the altitude of the region whence the auroral light 

 proceeds, and still the greatest diversity of opinion seems to prevail 

 on this subject. Some observers have seen the light in such posi- 

 tions between themselves and neighboring objects as to demonstrate 

 that the aurora, like the lightning, descends to the very surface of 

 the earth and may even be entirely confined to the lowest stratum : 

 prominent among these are Captain Parry, Sir James Clark Ross 

 and Sir John Ross, his uncle. Dr. Walker and Prof. J. P. Lesley. 



Others, such as Dr. Richardson, Sir John Franklin, Silbermann, 

 have seen it so located among the clouds that its origin must be placed 

 at or below their level and, therefore, within a few thousand feet 

 of the earth's surface. On the other hand, those who have calcu- 



