VI INTRODUCTION. 



the chapters contained in them, have also been enlarged, amended, 

 and improved. 



In short, the author desires here to state to the friends and 

 students of this beautiful and elevating science, that it is pro- 

 gressive — that occupying with regard to it somewhat the relation 

 of a pioneer, his object has been, is, and shall be, truth. 



The primary object of the researches connected with " the 

 Wind and Current Charts," out of which has grown this 

 Treatise, 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 

 currents daily encountered during the voyage, it was plain that 

 navigators hereafter, by consulting such a Record, 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 

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

 chart for reference. It would spread out before him the tracts 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 experience 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, theiefore, set 

 out upon his first voj^age with as much confidence in his know- 

 ledge, as to the winds and currents he might expect to encounter, 

 as though he himself had already been that way a thousand times 

 before. 



Such a chart could not fail to commend itself to intelligent 

 ship masters, and such a chart was constructed for them. They 



