BAUER— THE COMPASS IN AERONAUTICS. 257 



observations to date do not possess, however, the requisite refine- 

 ment, and it is hoped that some day a non-magnetic airship and the 

 necessary instrumental appHances will be available for conducting 

 a magnetic survey of the aerial regions in the same manner as that 

 employed in the ocean-magnetic survey of the non-magnetic ship, 

 the Carnegie. 



Referring to the possible scientific work for airships, it will be of 

 interest to recall that the first scientific aerological observations in a 

 balloon were made in 1784 by an American physician. Dr. John 

 Jeffries, a graduate of Harvard College, residing at the time in 

 London. Dr. Jeffries presented a printed copy of the extremely in- 

 teresting narrative on his two aerial voyages- to Benjamin Franklin, 

 as also a manuscript copy ; both are now in the possession of the 

 American Philosophical Society. Other aeronautical papers and 

 letters of historical interest will be found among the magnificent col- 

 lection of " Frankliniana," belonging to the Society. 



2 In the second of these voyages, made on January 7, 1785, the English 

 Channel was successfully crossed for the first time by aerial flight. 



PROC. AMER. PHIL. SOC. , VOL. LVI, R, JUNE 21, I917. 



