M. Liais, having had the opportunity of applying a method, which he had
devised for measuring the height of aurorae boreales, to an aurora seen
at Cherbourg Oct. 31, 1853, found that the arc of the aurora was about
two and a half miles above the ground, at its lower edge.
Various observations made by Professor Olmsted, in conjunction with
Professor Twining, of New Haven, led him, on the contrary, to fix the
elevation on different occasions at forty-two, one hundred, and one
hundred and sixty miles. He claims that it is rarely less than seventy
miles from the earth, and never more than one hundred and sixty. He
also claims that its origin is cosmical,--or, in other words, that the
earth, in revolving in its orbit, at certain periods passes through a
nebulous body, which evolves this strange light in more or less
brilliancy, as the body is larger or smaller. To support this theory,
he attempted to establish that there were fixed epochs for its display
in the highest degree of brilliancy. The length of these periods was
from sixty to seventy years, and the next appearance was to be in 1890.
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