Had you followed Captain Ahab down into his cabin after the squall that took place on the night succeeding that wild ratification of his purpose with his crew, you would have seen him go to a locker in the transom, and bringing out a large wrinkled roll of yellowish sea charts, spread them before him on his screwed-down table. Then seating himself before it, you would have seen him intently study the various lines and shadings which there met his eye; and with slow but steady pencil trace additional courses over spaces that before were blank. At intervals, he would refer to piles of old log-books beside him, wherein were set down the seasons and places in which, on various former voyages of various ships, sperm whales had been captured or seen.

While thus employed, the heavy pewter lamp suspended in chains over his head, continually rocked with the motion of the ship, and for ever threw shifting gleams and shadows of lines upon his wrinkled brow, till it almost seemed that while he himself was marking out lines and courses on the wrinkled charts, some invisible pencil was also tracing lines and courses upon the deeply marked chart of his forehead.

But it was not this night in particular that, in the solitude of his cabin, Ahab thus pondered over his charts. Almost every night they were brought out; almost every night some pencil marks were effaced, and others were substituted. For with the charts of all four oceans before him, Ahab was threading a maze of currents and eddies, with a view to the more certain accomplishment of that monomaniac thought of his soul.

Now, to any one not fully acquainted with the ways of the leviathans, it might seem an absurdly hopeless task thus to seek out one solitary creature in the unhooped oceans of this planet. But not so did it seem to Ahab, who knew the sets of all tides and currents; and thereby calculating the driftings of the sperm whale's food; and, also calling to mind the regular, ascertained seasons for hunting him in particular latitudes; could arrive at reasonable surmises, almost approaching to certainties, concerning the timeliest day to be upon this or that ground in search of his prey.

So assured, indeed, is the fact concerning the periodicalness of the sperm whale's resorting to given waters, that many hunters believe that, could he be closely observed and studied throughout the world; were the logs for one voyage of the entire whale fleet carefully collated, then the migrations of the sperm whale would be found to correspond in invariability to those of the herring-shoals or the flights of swallows. On this hint, attempts have been made to construct elaborate migratory charts of the sperm whale.*

*Since the above was written, the statement is happily borne out by an official circular, issued by Lieutenant Maury, of the National Observatory, Washington, April 16th, 1851. By that circular, it appears that precisely such a chart is in course of completion; and portions of it are presented in the circular. "This chart divides the ocean into districts of five degrees of latitude by five degrees of longitude; perpendicularly through each of which districts are twelve columns for the twelve months; and horizontally through each of which districts are three lines; one to show the number of days that have been spent in each month in every district, and the two others to show the number of days in which whales, sperm or right, have been seen."

Besides, when making a passage from one feeding-ground to another, the sperm whales, guided by some infallible instinct--say, rather, secret intelligence from the Deity--mostly swim in veins, as they are called; continuing their way along a given ocean-line with such undeviating exactitude, that no ship ever sailed her course, by any chart, with one tithe of such marvellous precision. Though, in these cases, the direction taken by any one whale be straight as a surveyor's parallel, and though the line of advance be strictly confined to its own unavoidable, straight wake, yet the arbitrary vein in which at these times he is said to swim, generally embraces some few miles in width (more or less, as the vein is presumed to expand or contract); but never exceeds the visual sweep from the whale-ship's mast-heads, when circumspectly gliding along this magic zone. The sum is, that at particular seasons within that breadth and along that path, migrating whales may with great confidence be looked for.

And hence not only at substantiated times, upon well known separate feeding-grounds, could Ahab hope to encounter his prey; but in crossing the widest expanses of water between those grounds he could, by his art, so place and time himself on his way, as even then not to be wholly without prospect of a meeting.

There was a circumstance which at first sight seemed to entangle his delirious but still methodical scheme. But not so in the reality, perhaps. Though the gregarious sperm whales have their regular seasons for particular grounds, yet in general you cannot conclude that the herds which haunted such and such a latitude or longitude this year, say, will turn out to be identically the same with those that were found there the preceding season; though there are peculiar and unquestionable instances where the contrary of this has proved true. In general, the same remark, only within a less wide limit, applies to the solitaries and hermits among the matured, aged sperm whales. So that though Moby Dick had in a former year been seen, for example, on what is called the Seychelle ground in the Indian ocean, or Volcano Bay on the Japanese Coast; yet it did not follow that were the Pequod to visit either of those spots at any subsequent corresponding season, she would infallibly encounter him there. So, too, with some other feeding-grounds, where he had at times revealed himself. But all these seemed only his casual stopping-places and ocean-inns, so to speak, not his places............