miRODUGTION TO THE FIRST EDITIOK-1855. 



The primary object of " The Wind and Current Charts," out 

 of which has grown this Treatise on the Physical Geography of 

 the Sea, was to collect the experience of every navigator as to the 

 winds and currents of the ocean, to discuss his observations upon 

 them, and then to present the world with the results on charts for 

 the improvement of commerce and navigation. 



By putting down on a chart the tracks of many vessels on the 

 same voyage, but at different times, in different years, and during 

 all seasons, and by projecting along each track the winds and cur- 

 rents daily encountered, it was plain that navigators hereafter, by 

 consulting this chart, would have for their guide the results of the 

 combined experience of all whose tracks were thus pointed out. 



Perhaps it might be the first voyage of a young navigator to 

 the given port, when his own personal experience of the winds to 

 be expected, the currents to be encountered by the way, would it- 

 self be blank. If so, there would be the wind and current chart. 

 It would spread out before him the tracks of a thousand vessels 

 that had preceded him on the same voyage, wherever it might be, 

 and that, too, at the same season of the year. Such a chart, it 

 was held, would show him not only the tracks of the vessels, but 

 the experience also of each master as to the winds and currents 

 by the way, the temperature of the ocean, and the variation of the 

 needle. All this could be taken in at a glance, and thus the young 

 mariner, instead of groping his way along until the lights of expe- 

 rience should come to him by the slow teachings of the dearest 

 of all schools, would here find, at once, that he had already the 

 experience of a thousand navigators to guide him on his voyage. 

 He might, therefore, set out upon his first voyage with as much 

 confidence in his knowledge as to the winds and currents he might 

 expect to meet with, as though he himself had already been that 

 way a thousand times before. 



Such a chart could not fail to commend itself to intelligent 



