tion of dust-particles in the air, on the Continent as well as i

inch of the air: whereas in the following year he counted 250,000. He observed, however, that where the

e wind was blowing from the mountains; but increased to

on his second visit, he counted no less than 166,000. This was accounted for by a thick haze, which rendered the lower Alps scarcely visible. The upper

were registered; but in the middle of the storm he counted only 13,000. There was a heavy fall of hail at this time, and he

0 in a cubic inch. On looking about, he found that the direction of the wind had changed, bringing down the purer upper air t

he mountain southerly, south-easterly, and easterly winds were more impregnated with dust-particles, sometimes containing 133,000 per cubic inch. Northerly winds brought pure air. The observations at sea-leve

tances; (3) dust rises to the tops of mountains during the day; (4) with much dust there is much haze; (5) high humidity causes great thickness of the atmosphere, if accompanied by a great amount of dust,