The truth is, that neither the seamanship of Columbus nor the invention of the compass or the astrolabe made his first voyage successful. Probably any one of the thousands of contemporary Italian sailors could have found the West Indies as easily as Columbus found them, provided the hypothetical sailor had possessed sufficient resolution to sail westward until the land should stop his way. What we should properly be called upon to admire in Columbus as a navigator of unknown seas is the obstinacy with which he adhered to his purpose of sailing due west until land should be found, no matter if it should take all summer. It was an obstinacy akin to that with which our great Union General fought his last campaign. Such obstinacy will sometimes accomplish greater results than the most skilful navigator or the profoundest strategist could accomplish. Had the man who discovered our country or the man who saved it been less obstinate, American history would have been widely different from what it has been. As the astrolabe has been mentioned several times in the course of this narrative, it may be well to describe it, especially as it is now obsolete. It was an instrument of considerable size, made of some convenient material--usually either metal or wood, or both--and fitted with various contrivances for the purpose of observing the heavenly bodies. When a navigator took an observation with the astrolabe he immediately went below and “worked it up” with the help of a slate and pencil, and in accordance with the rules of arithmetic and algebra. The result was a series of figures which greatly surprised him, and which he interpreted according to the humor in which he happened to find himself. A skilful navigator who could guess his latitude with comparative accuracy generally found that an observation taken with the astrolabe would give him a result not differing more than eighty or ninety degrees from the latitude in which he had previously imagined his ship to be, and if he was an ingenious man he could often find some way of reconciling his observation with his guesses. Thus the astrolabe gave him employment and exercised his imagination, and was a great blessing to the lonesome and careworn mariner.