Highs travel somewhat more slowly; about 540 miles a day is the average in this country.

In summer a succession of these highs causes the frequent droughts of weeks which harass the West and New England.

It will be recalled that the trade-wind lowlands and the extra-tropical belt of highs are the great desert belts at present.

The belt of highs is arid because there, too, air is being warmed, but in this case by descending from aloft.