Aurora Borealis Small 320×310 Medium 640×621 Large 1024×993 Download Tiff Original 2400×2327 | (4.2 MB) Description Auroras are caused by the passage of electricity through the rare air of the upper regions. Keywords electricity, northern lights, weather Galleries Astronomy Source: Edwin J. Houston, The Elements of Physical Geography, for the use of Schools, Academies, and Colleges. (Philadelphia: Eldredge & Brother, 1891) 112
