Note 10 — V THE SOLAR DUST IN THE ATMOSPHERE—POLAR LIGHTS AND THE VARIATIONS OF TERRESTRIAL MAGNETISM

The very highest strata of our atmosphere (at levels of from 20 to 80 km., 15 to 50 miles) may perhaps form an exception. The luminous clouds which were observed in the years 1883-1892 at Berlin (after the eruption of Krakatoa), and which were floating at a very high level, showed a drift with regard to the surface of the earth opposite to the drift of the cirrus clouds, which are directed eastward.