Repository: UIHistories Project: Board of Trustees Minutes - 1871 [PAGE 157]

EXTRACTED TEXT FROM PAGE:

149 sometimes called the counter-trade winds, thread through and flow on *n the higher regions of the air, over the same lines, toward the northeast in our latitude, producing on each side of the equator a zone about twenty degrees or some twelve hundred miles wide of regular trade winds and periodical rains, and, descending, to wheel into line again, for a new advance toward the equator, producing a wide belt or zone of variable rain storms, under which we live, that swings toward the north or the south as the sun advances or recedes, with some little degree of regularity, giving us what we call our equinoxial and other storms—all this is well known to all. The manner in which this return current or counter-trade wind, blowing toward the northeast, high up over our heads, and bringing us all our greatest rain or snow storm, continues to bear along its watery clouds, and steadfastly refuses, for whole days or weeks in succession, to mingle with the lower currents, from whatever quarter they may blow, carrying their own burden of lower clouds, may be seen by any one who will lie down on his back and watch as they pass these two different and often directly opposite currents of winds and clouds, though the reason why such currents refuse so obstinately to mingle together cannot be fully explained by any one, no more than we can explain why the waters of the Gulf Stream refuse to mingle with that of the surrounding ocean, in despite of the awful force of all possible storms, winds, waves and tides. It may be that they are in a state of constant electrical repulsion, like the redoubling rings of smoke blown from the bowl of a pipe. These are perhaps the principal geological and astronomical causes of changes of climate to any extent known to us. I have made no account of the well-known fact that the temperature of the earth seems to increase in a regular ratio as we descend into it, because, to my apprehension, that fact has as yet taught us nothing but the bare fact itself. It may proceed simply from the different ratios of the absorption and radiation of heat from the surface, or from the centrifugal force and force of gravity co-operating with the force of the heat derived from the sun, to augment the heat in a spherical plane at a small distance below the surface of the earth, as Dr. James seems to have supposed ; or it may arise from a thousand unknown causes, which would limit the phenomena wholly to the surface, or near the surface of the earth, without implying that there is heat, or indeed anything else but air or gas, it may be, at the center of the globe. Certainly, it is no proof that there is now or ever was in that center any heat, not constantly generated by its natural and constant actions and forces, from simple causes above described. If the gadflies in boring into an ele-