June 1873, Mt. Lyell Studies, Glacier Cañon Erosion Image 31

is visible is bounded by 2 circles drawn upon the earth’s surface, within the aurora-pole for a centre & [radii] of 8 [degrees] & 28 [degrees] measured on the circumference of the globe. It touches only to a limited extent countries inhabited by races of European origin & even in the middle of this [belt] area there is a belt passing over middle Greenland, S. Spitzbergen & Franz Joseph Land, where the common arc forms only a faint, very widely extended luminous veil in the zenith… This belt divides the regions where these luminous arcs are seen principally to the S. from those in wh they mainly appear on the N.rn horizon. In the area next the ar-pole only the smaller, in middle Scandinavia only the larger, more irregularly formed luminous crowns are seen. But in the latter region, as in S.rn British America, ar [aurora] storms & ray & drapery auroras are instead common, & these appear to lie nearer the surface of the earth than the arc aurora most of the Polar Expeditions have wintered so near the ar-pole that the common ar arc there lay under or quite near the horizon, & as the ray ar appears to occur seldom within this circle, the reason is easily explained why the winter night was so seldom illuminated by the Ar at the winter quarters of these expeditions, & why the description of this phenomenon plays so small a part in their sketches of travel. |end|https://scholarlycommons.pacific.edu/jmj-all/1588/thumbnail.jp