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Rh even still, some outstanding errors which are to be accounted for, but they are so small, that any further approximation would practically be of no service to the mariner.

Every time the sailor takes a lunar with his sextant, he has a practical illustration of the triumphs of astronomy, in assigning the exact place of the moon at any moment in the heavens. Still, every mind must feel the more startling effect produced, when, in an eclipse of the sun, the first impact of the moon coincides with the very beat of the clock predicted by the astronomer; and predicted, too, not as an empirical deduction from previously observed regularity but as the result of the all-pervading force of gravitation, which not only produces the most bewildering inequalities, but furnishes, by its simple law, a key by which they may be all reduced to the most wonderful symmetry and order.

We have, however, on the present occasion, taken up the subject of eclipses, not so much with the view of illustrating the accuracy of astronomical calculations, as of turning the attention of our readers to the physical aspects of the total eclipse on the 18th of July 1860. No total eclipse has been witnessed in these islands for several generations. The last observed at Greenwich, was in 1715; and there was an interval of 375 years between this and the previous one. The chance of a person ever witnessing in his lifetime a total eclipse in any given spot of the earth's