"During our stay on the summit, we took much pleasure and interest in watching the various movements of the clouds; this day in particular, they attracted our attention; the whole island beneath us was covered with a dense white mass, in the center of which was the cloud of the volcano rising like an immense dome. All was motionless until the hour arrived when the sea-breeze set in from the different sides of the island; a motion was then seen in the clouds, at the opposite extremities, both of which seemed apparently moving toward the same center, in undulations, until they became quite compact, and so contracted in space as to enable us to see a well defined horizon; at the same time there was a wind from the mountain, at right angles, that was affecting the mass, and drawing it asunder in the opposite direction. The play of these masses was at times in circular orbits, as they became influenced alternately by the different forces, until the whole was passing to and from the center in every direction, assuming every variety of form, shape and motion. "On other days clouds would approach us from the S. W. when we had a strong N. E. trade-wind blowing, coming up with cumulus front, reaching the height of about eight thousand feet, spreading horizontally, and then dissipating. At times they would be seen lying over the island in large horizontal sheets as white as the purest snow, with a sky above of the deepest azure blue that fancy can depict. I saw nothing in it approaching to blackness at any time." (Exploring Expedition, vol iv. p. 155). Here, in the last paragraph, we have the whole truth disclosed. The N. E. trade was blowing on Mauna Loa, 13,000 feet above the sea, and the sea-breeze blew in on the _leeward side_, its moisture condensing over the volcanic island, but without rising _up the mountain_, or _through the surface-trade_, or _above 8,000 feet_. So, too, the celebrated aeronaut, Mr. Wise, in the course of more than a hundred ascensions, some during high wind, and others during rain storms, never met with an ascending current, except in a single instance, in the body of a hail-cloud, and then there were descending currents also, the usual intestine motion of hail-cloud with its opposite polarities. I copy a description of his passage through the clouds of a rain-storm, and his floating a long period above them; and there was no ascending current which disturbed their horizontal repose or progression. The double layer is not uncommon--condensation taking place at the connection of the upper and lower portions of the trades, with the surrounding atmosphere; or in the trade, and by _induction in the surface atmosphere_ at the same time. Such instances are frequently visible, and if his ascensions had been undertaken at other times in stormy weather he would have seen more of them.