Aurora Borealis and icebergs, Arctic, 1849.

UNSPECIFIED - MAY 21: Plate taken from the �Illustrated London News�. The name given to this phenomenon signifies Northern Daybreak, and is very appropriate, because the Aurora usually appears in the north and gives a light not unlike that of the dawn of day. The cause of the Aurora has never been satisfactorily explained, although it is generally attributed to electricity which, in its passage from the north pole to the equator, is supposed to become visible in this form. The expedition of 1848-1849, involving the ships �Investigator� and �Enterprise� was led by James Clark Ross, one of a series to depart in search of Sir John Franklin (1786-1847), who had disappeared in 1847 whilst in search of the Northwest Passage. (Photo by SSPL/Getty Images)