Adams thought the matter trivial, and did not reply. Airy, therefore, took no interest in the investigations, and no steps were taken to search for the unseen planet. Meanwhile the Rev. W. R. Dawes happened to see Adams’ papers lying at Greenwich, and wrote to his friend, the well-known astronomer Lassell, who was in possession of a very fine reflector, erected at his residence near Liverpool, asking him to search for the planet. But Lassell was suffering from a sprained ankle, and Dawes’ letter was accidentally destroyed by a housemaid. So Adams’ theory remained in obscurity. The question now came under the notice of _François Jean Dominique Arago_ (1786-1853), the director of the Paris Observatory. He recognised in a young friend of his a rising genius, who was competent to solve the problem. Urban Jean Joseph Le Verrier, born at Saint Lo, in Normandy, in 1811, became in 1837 astronomical teacher in the École Polytechnique, and in 1853 director of the Paris Observatory. In consequence of differences with his staff he was obliged, in 1870, to resign from this position, but two years later was restored to the post, which he held till his death on September 23, 1877. In 1845, ignorant of the fact that Adams had already solved the problem, Le Verrier began his investigations of the irregular motions of Uranus. In a memoir communicated to the Academy of Sciences in November of that year, he demonstrated that no known causes could produce these disturbances. In a second memoir, dated June 1, 1846, he announced that an exterior planet alone could produce these effects. But Le Verrier had now before him the difficult task of assigning an approximate position to the unseen body, so that it might be telescopically discovered. After much calculation Le Verrier, in his third memoir (August 31, 1846), assigned to the planet a position in the constellation Aquarius. Meanwhile one of Le Verrier’s papers happened to reach Airy. Seeing its resemblance to Adams’ papers, which had been lying on his desk for months, his scepticism vanished, and he suggested to Challis that the planet should be searched for with the Cambridge equatorial. In July 1846 the search was commenced. The planet was actually observed on August 4 and 12, but, owing to the absence of star maps, it was not recognised. “After four days of observing,” he wrote to Airy, “the planet was in my grasp if I had only examined or mapped the observations.”