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.