Page:Physical Geography of the Sea and its Meteorology.djvu/67

 Rh one mile or one hundred miles in length, the effect of diurnal rotation is the same; and, whether the road be long or short, the tendency to run off, as you cross a given parallel at a stated rate of speed, is the same; for the tendency to fly off the track is in proportion to the speed of the train, and not at all in proportion to the length of the road. Now, vis inertæ and velocity being taken into the account, the tendency to obey the force of this diurnal rotation, and to trend to the right, is proportionably as great in the case of a patch of sea-weed as it drifts along the Gulf Stream, as it is in the case of the train of cars as they speed to the north along the iron track of the Hudson River, or the North-Western railway, or any other railway that lies nearly north and south. The rails restrain the cars and prevent them from flying off; but there are no rails to restrain the sea-weed, and nothing to prevent the drift matter of the Gulf Stream from going off in obedience to this force. The slightest impulse tending to turn aside bodies moving freely in water is immediately felt and implicitly obeyed.

114. Drift-wood on the Mississippi.—It is in consequence of this diurnal rotation that drift-wood coming down the Mississippi is so very apt to be cast upon the west or right bank. This is the reverse of what obtains upon the Gulf Stream, for it flows to the north; it therefore sloughs off (§ 111) to the east.

115. Effect of diurnal rotation upon.—The effect of diurnal rotation upon the winds and upon the currents of the sea is admitted by all—the trade-winds derive their easting from it—it must, therefore, extend to all the matter which these currents bear with them, to the largest iceberg as well as to the smallest spire of grass that floats upon the waters, or the minutest organism that the most powerful microscope can detect among the impalpable particles of sea-dust. This effect of diurnal rotation upon drift will be frequently alluded to in the pages of this work.

116. Formation of the Grand Banks.—In its course to the north, the Gulf Stream gradually tends more and more to the eastward, until it arrives off the Banks of Newfoundland, where its course becomes nearly due east. These banks, it has been thought, deflect it from its proper course, and cause it to take this turn. Examination will prove, I think, that they are an effect, certainly not the cause. It is here that the frigid current already spoken of (§ 85), and its icebergs from the north, are met and melted by the warm waters of the Gulf. Of course the loads of earth,