FIRST EUROPEAN TOUR CONTINUED—LEVERRIER AND THE PARIS OBSERVATORY—ROME—HARRIET HOSMER—OBSERVATORY OF THE COLLEGIO ROMANO—SECCHI
At this time, the feeling between astronomers of Great Britain and those of the United States was not very cordial. It was the time when Adams and Leverrier were contending to which of them belonged the honor of the discovery of the planet Neptune, and each side had its strong partisans.
Among Miss Mitchell's papers we find the following with reference to this subject:
"… Adams, a graduate of Cambridge, made the calculations which showed how an unseen body must exist whose influences were felt by Uranus. It was a problem of great difficulty, for he had some half-dozen quantities touching Uranus which were not accurately known, and as many wholly unknown concerning the unseen planet. We think it a difficult question which involves three or four unknown quantities with too few circumstances, but this problem involved twelve or thirteen, so that x, y, z reached pretty high up into the alphabet. But Adams, having worked the problem, carried his work to Airy, the Astronomer Royal of England, and awaited his comments. A little later Leverrier, the French astronomer, completed the same problem, and waiting for no authority beyond his own, flung his discovery out to the world with the self-confidence of a Frenchman….
"… When the news of the discovery of Neptune reached this country, I happened to be visiting at the observatory in Cambridge, Mass. Professor Bond (the elder) had looked for the planet the night before I arrived at his house, and he looked again the evening that I came.
"His observatory was then a small, round building, and in it was a small telescope; he had drawn a map of a group of stars, one of which he supposed was not a star, but the planet. He set the telescope to this group, and asking his son to count the seconds, he allowed the stars to pass by the motion of the earth across the field. If they kept the relative distance of the night before, they were all stars; if any one had approached or receded from the others, it was a planet; and when the father looked at his son's record he said, 'One of those has moved, and it is the one which I thought last night was the planet.' He looked again at the group, and the son said, 'Father, do give me a look at the new planet—you are the only man in America that can do it!' And then we both looked; it looked precisely like a small star, and George and I both asked, 'What made you think last night that it was the new planet?' Mr. Bond could only say, 'I don't know, it looked different from the others.'
"It is always so—you cannot get a man of genius to explain steps, he leaps.
"After the discovery of this planet, Professor Peirce, in our own country, declared that it was not the planet of the theory, and therefore its discovery was a happy accident. But it seemed to me that it was the planet of the theory, just as much if it varied a good deal from its prescribed place as if it varied a little. So you might have said that Uranus was not the Uranus of the theory.
"Sir John Herschel said, 'Its movements have been felt trembling along the far-reaching line of our analysis, with a certainty hardly inferior to ocular demonstration.' I consider it was superior to ocular demonstration, as the action of the mind is above that of the senses. Adams, in his study at Cambridge, England, and Leverrier in his closet at Paris, poring over their logarithms, knew better the locus of that outside planet than all the practical astronomers of the world put together….
"Of course in Paris I went to the Imperial Observatory, to visit Leverrier. I carried letters from Professor Airy, who also sent a letter in advance by post. Leverrier called at my hotel, and left cards; then came a note, and I went to tea.