consequently in our calculations we have taken no account. We know that every visible planet exercises some influence on the motion of this distant one; for all these we have already made allowance. Can there be another planet beyond all which have been yet discovered, but the existence of which makes itself apparent to us by these unexplained irregularities of that which we have seen and measured? If so, where is it?—what is its size?—which way is it travelling?—and with what velocity?
"These are the questions this young French student has proposed to himself: and he feels that his science will enable him to find an answer to them. By a singular coincidence, the same daring exploit is tried almost at the same time, with some priority indeed, by another young man at Cambridge, Mr. Adams, each ignorant of what the other is doing, and each succeeding by his own independent processes of investigation. But let us return to Paris. I will not endeavor to explain to you the steps of the calculation: you will probably be satisfied by my assuring you that they are most intricate and laborious. But the work is done: the results are beginning to appear, and at last M. Leverrier is able to say, with the confidence of consummate skill, 'Yes: I have found it! There is such a planet. Human eye has never yet looked on it, with the true appreciation of its nature: but it has been walking its appointed round from immemorial time: here is an account of its mass; this is the direction in which it is moving; this is the point where, at this moment, if you will look for it, you will find it.' All this the young astronomer, who himself has not yet seen this new world, except upon the paper of his elaborate calculations, dares to announce to a friend at Berlin, better furnished than himself with the means of making the actual observation. A new celestial atlas is then in course of publication in Prussia; and, by a happy chance, the sheet has just issued from the press which exhibits that portion of the skies in which Leverrier has placed his unseen planet. This is eagerly compared with an old map; and, almost exactly in the spot fixed on by the young Frenchman, a star is marked, not noted in the older map. The telescope is instantly turned to it and the discovery is complete; the planet is there! Surely, it is not without reason that one of our poets has said—
"An undevout astronomer is mad!"
