The red dust we found off the Cape de Verds assists us in certain degrees. We know some of the agents--the diurnal motion of the earth, and the sun's heating rays. There are certain counteracting or disturbing causes from which the surface-winds deviate from the courses I have described. Some lands are covered with forests, others with marshes, others with sand. All these may be disturbing causes--so are lofty mountains. From these causes, and the more powerful effect of the sun's rays in one place than in another, hurricanes and typhoons occur, and the monsoons are made to blow--the harmattan on the west coast of Africa; the simoon, with its deadly breath, in Arabia; the oppressive sirocco in the Mediterranean. What I have said will explain that beautiful passage in Ecclesiastes, 1st chapter, 6th verse, which shows the exactness of the sacred writers whenever they do introduce scientific subjects: `The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits.' Who gave Solomon this information? I doubt if any of his sages possessed that scientific knowledge which has only been attained by philosophers of late years. Perhaps I may still more clearly explain to you the cause of the circulation of the atmosphere. I told you that there were two agents at work--diurnal motion, and the heat of the sun; but to these may be added the cold of the poles, which contracts the air. Suppose the globe at rest, and covered with one uniform stagnant mass of atmosphere; suddenly heat, cold, and the diurnal motion commence their operations. The air about the equator would expand, that about the poles contract. Thus two systems of winds would commence to blow--one above, from the equator towards the poles; and as thus a vacuum would be left below, a current would come from the poles to supply its place. The diurnal motion prevents these currents running in straight lines. That coming from the poles will appear to have easting in them, and those going towards the poles westing. Not only, however, is the level of the atmosphere changed by the heating rays of the sun, but its specific gravity. Thus the heated current moves more easily and rapidly than the colder; and the latter, consequently, turns back a portion of what was going towards the poles, and adjusts the equilibrium of the atmosphere. I have already shown you the great importance of the circulation of the air in the economy of nature; and how, among the many offices of the atmosphere, it distributes moisture over the surface of the earth, making the barren places fruitful, and tempering the climates of different latitudes, fitting them as the abode of civilised man. But I will not pursue the subject further just now. You must do that for yourselves. Try and remember what I have said, and think about it whenever you have an opportunity." Jerry and I thanked the captain for