By doing farm work and by teaching Burroughs saved enough money to enter an institute not far from his home. He returned from his first visit to New York "with an empty pocket and an empty stomach, but with a bagful of books." All his money had been spent at second-hand book-stalls. For several years he taught school, marrying a pupil, Ursula North, in the meantime. He was twenty-six when, engaged in teaching near West Point, he "chanced upon the works of Audubon" in the library of the Military Academy. He relates, "It was like bringing together fire and powder. I was ripe for the adventure; I had leisure, I was in a good bird country, and I had Audubon to stimulate me. How eagerly and joyously I took up the study! It gave to my walks a new delight; it made me look upon every grove and wood as a new storehouse of possible treasures." His earliest contribution to Nature literature, a paper entitled "The Return of the Birds," was completed when he was a clerk in the office of the Comptroller of the Currency, in Washington. He held this position for ten years. In his spare moments he studied birds and wrote about them, finding that "he had only to unpack the memories of the farm boy to get at the main things about the common ones." The love of the great Nature essayist for his native countryside pervades much that he has given us. "Take the farm boy out of my books, and you have robbed them of something that is vital and fundamental," he avows. From the beginning he liked to write about rustic things--"sugar-making, cows, haying, stone walls." Journeys to England, to the West Indies, to Alaska with the Harriman Expedition, to the Grand Canyon and the Yosemite, which he explored with his friend John Muir, to the Yellowstone (he visited the National Park in 1903 as the chosen companion of President Theodore Roosevelt), widened the sphere of John Burroughs' happy bird and flower hunting-grounds. But he still loves best the scenes of his boyhood, and he often returns in summer to the Catskills to revive memories, and write, and muse on the beauties of the Delaware County hills and vales. His home above the Hudson, at Riverby, West Park, where he has lived for nearly half a century, and Slabsides, his tree-shaded chestnut-barked work cabin on a nearby hill, are places of pilgrimage for children, poets, wise men. "Nature lovers?" said a visitor. "Yes, and John Burroughs lovers, too."