This leads me to speak of my watchmate for nine months,—­ and, taking him all in all, the most remarkable man I had ever seen,—­ Tom Harris.  An hour, every night, while lying in port, Harris and I had the deck to ourselves, and walking fore and aft, night after night, for months, I learned his character and history, and more about foreign nations, the habits of different people, and especially the secrets of sailors’ lives and hardships, and also of practical seamanship (in which he was abundantly capable of instructing me), than I could ever have learned elsewhere.  His memory was perfect, seeming to form a regular chain, reaching from his earliest childhood up to the time I knew him, without a link wanting.  His power of calculation, too, was extraordinary.  I called myself pretty quick at figures, and had been through a course of mathematical studies; but, working by my head, I was unable to keep within sight of this man, who had never been beyond his arithmetic.  He carried in his head, not only a log-book of the voyage, which was complete and accurate, and from which no one thought of appealing, but also an accurate registry of the cargo, knowing where each thing was stowed, and how many hides we took in at each port.

One night he made a rough calculation of the number of hides that could be stowed in the lower hold, between the fore and main masts, taking the depth of hold and breadth of beam (for he knew the dimensions of every part of a ship before he had been long on board), and the average area and thickness of a hide; and he came surprisingly near the number, as it afterwards turned out.  The mate frequently came to him to know the capacity of different parts of the vessel, and he could tell the sailmaker very nearly the amount of canvas he would want for each sail in the ship; for he knew the hoist of every mast, and spread of each sail, on the head and foot, in feet and inches.  When we were at sea, he kept a running account, in his head, of the ship’s way,—­ the number of knots and the courses; and, if the courses did not vary much during the twenty-four hours, by taking the whole progress and allowing so many eights southing or northing, to so many easting or westing, he would make up his reckoning just before the captain took the sun at noon, and often came very near the mark.  He had, in his chest, several volumes giving accounts of inventions in mechanics, which he read with great pleasure, and made himself master of.  I doubt if he forgot anything that he read.  The only thing in the way of poetry that he ever read was Falconer’s Shipwreck, which he was charmed with, and pages of which he could repeat.  He said he could recall the name of every sailor that had ever been his shipmate, and also of every vessel, captain, and officer, and the principal dates of each voyage; and a sailor whom we afterwards fell in with, who had been in a ship with Harris nearly twelve years before, was much surprised at having Harris tell him