"Water," answered Captain Frankland.  "Remember those dense fogs, like wet blankets, which so continually rise in those calm regions to the south of us; they are caused by vapours rising from the sea, and leaving its salt behind.  This vapour must go somewhere, and it certainly does not fall in any place near the region where it is drawn up.  See the beautiful provision of Nature to supply with fertilising moisture the many districts of the earth!  This damp vapour, of which we shall by-and-by have a specimen, rises into the upper regions of the air, and is there wafted steadily on till it reaches the northern portion of the globe.  It is raised by the powerful rays of the sun during the southern summer, and with it a considerable amount of heat is carried off which remains latent.  When it reaches the far colder atmosphere of the north, it is formed into clouds, and condensed, and then precipitated in rain. In the southern hemisphere there is, as you know, a larger proportion of sea than in that of the north; and thus it serves as a reservoir to supply those spots which would otherwise be arid deserts, with an abundant supply of the chief necessary of life.  The whole of nature is full of similar beautiful arrangements for making the globe a convenient habitation for man, clearly to be perceived if men would but open their eyes to behold them."