398 THE DEPTHS OF THE SEA. [CHAP. vm. 



the red stream widening out and becoming paler 

 over the general surface of the water till it reaches 

 the opposite edge, and very shortly the rapidly 

 heightening colour of a hand along the opposite 

 wall indicates an accumulation of the coloured water 

 where its current is arrested. If we now dip the 

 hand into the water of the centre of the hath, a warm 

 bracelet merely encircles the wrist ; while at the end 

 of the bath opposite the warm influx, the hot water, 

 though considerably mixed, envelopes the whole hand. 



The North Atlantic forms a basin closed to the 

 northward. Into the corner of this basin, as into a 

 bath, with a north-easterly direction given to it by 

 its initial velocity, as if the supply pipe of the bath 

 were turned so as to give the hot water a definite 

 impulse, this enormous flood is poured, day and 

 night, winter and summer. When the basin is full 

 and not till then overcoming its northern impulse, 

 the surplus water turns southwards in a southern 

 eddy, so that there is a certain tendency for the 

 hot water to accumulate in the northern basin, 

 to ' bank down' l along the north-eastern coasts. 



It is scarcely necessary to say that for every unit 

 of water which enters the basin of the North 

 Atlantic, and which is not evaporated, an equivalent 

 must return. As cold w^ater can gravitate into the 

 deeper parts of the ocean from all directions, it is 

 only under peculiar circumstances that any move- 

 ment having the character of a current is induced; 



1 Ocean Currents. An Address delivered to the Eoyal United 

 Service Institution June 15th, 1871. By J. K. Laughton, M.A., 

 Naval Instructor at the Eoyal Naval College. (From the Journal of 

 the Institution, vol. xv.) 



