THE GULF STREAM. 3^ 



the effects pro<^iaced upon the di'ift matter of the stream by the 

 dim'iial rotation of the earth. 



113. Take, for iUustration, a railroad that lies north and south 

 Illustration. in OUT hemisphere. It is weU known to engineers 

 that when the cars are going north on such a road, their tendency 

 is to run off on the east side ; but when the train is going south, 

 their tendency is to run off on the west side of the track — i. e., 

 always on the right-hand side. Y/hether the road be one mile or 

 one hundi^d 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 inertife and velocity being taken into the accomit, 

 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 Iiiver, 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 diift matter of the Gulf Stream 

 fi-om going off in obedience to this force. The slightest impulse 

 tending to tm^n aside bodies moving li'eely in water is inmiediately 

 felt and implicitly obeyed. 



114. It is in consequence of this dim-nal rotation that drift-wood 

 Drift-wood on the coming dowu the Mississippi is so very apt to be cast 

 Mississippi. 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. The effect of diurnal rotation upon the winds and upon the 

 Effect of diurnal ro- curreuts of the sca is admitted by all — the trade-vvinds 

 tation upon. dcrivo their easting from it — it must, therefore, ex- 

 tend to all the matter which these cmTcnts 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 diui-nal rotation upon di'iit will be frequently alluded 

 to in the pages of this w^ork. 



116. In its com^se to the north, the Gulf Stream gradually trends 

 Formation of the moro and more to the eastward, until it arrives off 



Orand Banks. 



