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 progressive—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, therefore, set out upon his first voyage with as much confidence in his knowledge, 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
