CnAP. II.] INERTION. 23 



enters, and it will consequently have a tendency to 

 change its meridian westwards. 



In the former case, that which changes its latitude 

 rushes on in advance of the latitude entered ; and 

 in the latter case, the latitude entered rushes on in 

 advance of that which enters it. The former may be 

 called a tendency to run eastwards, and the latter 

 a tendency to fall westwards. 



The change eastwards is in fact a tendency of the 

 water to part from, or run on in advance of, a surface 

 of less velocity ; and the change westwards, a fiilling 

 of the water against a surface of greater velocity with 

 which the change of latitude brings it into contact.^ 



^ It is greatly to be regretted that it has become customary to 

 use terms, in reference to the direction of ocean currents, in exactly 

 the opposite sense to that in which the same terms are used in re- 

 ference to the winds. This custom is so firmly established that, 

 as the advantages to be gained by altering it are not perhaps 

 sufficient to repay the temporary confusion consequent on a change 

 in the use of terms, the idea of changing the custom cannot perhaps 

 be entertained; though a judicious use of terms has more to do 

 with the progress of any science, than is perhaps generally supposed. 

 In speaking of the wind, the terms used denote the direction from 

 which the wind blows ; whereas, in speaking of ocean currents, the 

 terms used denote, not the direction /j-om which the current runs, 

 but that towards which it runs. Thus an easterly wind denotes a 

 wind running from east to west, but in the ocean an easterly current 

 denotes a current running from west to east. In order, in some 

 measure, to obviate the confusion which this injudicious use of 

 terms tends to cause, I have invariably used the termination ' ward ' 

 instead of ' ly,' in reference to ocean currents, so that as an easterly 

 loind denotes a wind running from the east, an east-ward current 

 denotes a current running towards the east. The ordinary use of 

 these terms has been so confused, and their relative meanings so 



