His reception encouraged him to proceed immediately with his plans of publication. It was a vast undertaking which it would take probably sixteen years to accomplish, and when his first drawings were delivered to the engraver he had not a single subscriber. His friends pointed out the rashness of the project and urged him to abandon it. "But my heart was nerved," he exclaims, "and my reliance on that Power on whom all must depend brought bright anticipations of success." Leaving his work in the care of his engravers and agents, in the summer of 1828 he visited Paris, and received the homage of the most distinguished men of science in that capital. Humboldt too, whose gigantic intelligence arose above all others in central Europe, became his warm friend, and remained until his death a sympathizing correspondent. The ensuing winter was passed in London, and in April, 1829, he returned to America to explore anew the woods of the middle and southern states. Accompanied by his wife he left New Orleans on the eighth of January, 1830, for New-York, and on the twenty-fifth of April, just a year from the time of his departure, he was again in the Great Metropolis. Before the close of 1830, he had issued his first volume, containing one hundred plates, representing ninety-nine species of birds, every figure of the size and colors of life. The applause with which it was received was enthusiastic and universal. The kings of England and France had placed their names at the head of his subscription list; he was made a fellow of the Royal Societies of London and Edinburgh; a member of the Natural History Society of Paris, and other celebrated institutions; and Cuvier, Swainson, and indeed the great ornithologists of every country, exhausted the words of panegyric in his praise. On the first of August, 1831, Audubon arrived once more in New-York, and having passed a few days with his friends there and in Philadelphia, proceeded to Washington, where the President and other principal officers of the government gave him letters of assistance and protection to be used all along the coasts and inland frontiers where there were collectors of revenue or military or naval forces. He had previously received similar letters from the king's ministers to the authorities of the British colonies.