VI INTRODUCTION. 



and not to be foimd in any of its predecessors. Most, if not all the 

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

 improved. 



In short, the author deshes 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 Y\^ind 

 and Cm^rent Charts," out of which has gTown this Treatise, was to 

 collect the experience of every navigator as to the winds and 

 ciuTcnts of the ocean, to discuss his observations upon them, and 

 then to present the world Vfith the results on charts for the im- 

 provement 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 dm^ing 

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

 rents daily encountered dui^ing the voyage, it was plain that navi- 

 gators hereafter, by consultmg 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 na^sdgator to the 

 given port, when his own personal experience of the mnds to be 

 expected, the currents to be encountered by the way, would itself be 

 blank. If so, there would be the wind and cmTcnt chart for refer- 

 ence. 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 cm-rents 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 groj)ing his way along until the lights of experience 

 should come to him by the slow teacliings of the dearest of all 

 schools, would here find, at once, that he had already the experi- 

 ence of a thousand navigators to guide him on his voyage. He 

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

 dence in liis knowledge as to the viinds 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 took it 



