Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 1.djvu/78

12 season being scarcely over, I was glad to leave as soon as possible. A few days were sufficient to complete our observations, and procure a supply of live stock, fresh fruit, vegetables, and water; all of which, except water, are of excellent quality and moderate price.

We sailed from Port Praya on the morning of the 20th, and on that day the hourly register of the height of the barometer, and the temperature of the air and surface of the ocean, was substituted for the three-hourly observations hitherto recorded, chiefly for the purpose of marking the progress of barometric depression in approaching, and reascension in receding from, the equator, a phenomenon represented as being of the greatest and most universal influence, as it is in fact no other than a direct measure of the moving force by which the great currents of the trade winds are produced; so that the measure of its amount and the laws of its geographical distribution lie at the root of the theory of these winds.

In lat. 8° N., and long. 26° W., we entered the Variables, as the space between the N.E. and S.E. trades is called: here violent gusts of wind and torrents of rain alternate with calms and light baffling breezes, which, with the suffocating heat of the electrically-charged atmosphere, render this part of the voyage both disagreeable and unhealthy, especially in a flush-decked vessel, where the necessity of keeping the hatchways covered prevents the free circulation of air.