Meanwhile, Urbain Le Verrier, on 10 November 1845, presented to the "Académie des sciences" in Paris a memoir on Uranus, showing that the preexisting theory failed to account for its motion. On reading Le Verrier's memoir, Airy was struck by the coincidence and initiated a desperate race for English priority in discovery of the planet. The search was begun by a laborious method on 29 July. Only after the discovery of Neptune on 23 September 1846 had been announced in Paris did it become apparent that Neptune had been observed on 8 and 12 August but because Challis lacked an up-to-date star-map it was not recognized as a planet.