Page:Physical Geography of the Sea and its Meteorology.djvu/300

274 place from the New Observatory in England, it has been ascertained that there the cloud region is from 2000 to 6500 feet high, with a thickness varying from 2000 to 3000 feet, and that its temperature at the top is not lower than it is at the bottom of the cloud, notwithstanding its thickness. We are also indebted to Piazzi Smyth for interesting observations on the cloud region in the belt of north-east trades and of the upper counter current there. They were made from the Peak of Teneriife, at the height of 12,200 feet, during the months of August and September, 1856. The cloud region of the trades was between 3000 and 5000 feet high; of the upper or south-west current, it was above the mountain. Islands only a few hundred feet high are generally cloud-capped in the trade-wind regions at sea; another indication that, with a given amount of moisture in the wind, the cloud region is higher at sea than it is over the land. For most of the time during his sojourn on the Peak, the sea was concealed from view by the cloud stratum below, though the sky was clear overhead. Farther to the north, in the Atlantic, however, as in the fog region about the meeting of the cool and warm currents near the Grand Banks, the look-out at the mast-head often finds himself above the fog or cloud in which the lower parts of the ship are enveloped. Going still farther towards the north and reaching the ice, the cloud region would again, for obvious reasons, mount up until you reached the open sea there, when again it would touch the earth with its smoke.

510. Fogs in the harbour of Callao.—In the harbour of Callao, in Peru, which is filled with the cool waters of Humboldt's current, I have seen the bay covered with a fog only a few inches high. I have seen fogs there so dense, and with outlines so sharp, as to conceal from view the row-boats approaching the ship's side. These fogs, especially early in the morning, will conceal from view not only the boat, but the persons of the crew up to the neck, so as to leave nothing visible but two rows of trunkless heads nodding catenaries at the oars, apparently skimming through the air and dancing on the fog in a manner at once both magical and fantastic. At other times the cloud stratum is thicker and higher. Then may be seen three masts coming into port with topgallant-sails and royals set, but no ship. These sails, nicely trimmed and swelling to the breeze in the sky swim along over the clouds, and seem like things in a fairy scene. However,