on a luminous Arch. 105 
in one place are different from thofe which form it to one at a 
diftant place, and confequently that no conclufion as to its 
height can be drawn from obfervations of it in different places. 
Attempts, however, have been made to determine the height 
of the aurora from fuch obfervations, and even from thofe of 
the Corona*; though the latter method muff; fu rely be per- 
fectly fallacious, and moft likely the former is fo too. 
Bergman. Opufc. Vol. V. 
Vol. LXXX. 
P 
