The poet in Whitman developed late and slowly while his early writings came only from the surface of his mind. But when he was scarcely in his teens he was publishing bits in Brooklyn papers and presently in George P. Morris's New York Mirror. At twelve he became an apprentice printer, the first occupation of a dozen writers who were more or less of Whitman's time. Whitman retained the interest in printing that he had acquired as a little boy standing on type-cases to reach the boxes. In old age he always knew "the easiest way out of printers' puzzles," as his disciple Horace Traubel said, and he watched his proofs with anxious eye, ready to add or omit a line in cases where a page struck him as too loose or crowded. He did not love his line "enough to let them spoil the page" he said, and once sacrificed nine for a blank space. He would send silver dollars with thanks to the proof takers for giving him clean dark proofs on paper that he liked. But while, in his boyhood, Whitman was a printer who was also beginning to write, his real occupation was absorbing impressions, historical impressions, among the rest, that attached him deeply from the first to the past and evolution of the country.