In August, 1843, in his twenty-first year, he became a student at Pembroke Academy. The term of ten weeks seemed ever afterwards in his memory one of the golden periods of his life. The teacher, Charles G. M. Burnham, was enthusiastic and magnetic, having few rules, and placing his pupils upon their honor. It was not so much what Carleton learned from books, as association with the one hundred and sixty young men and women of his own age, which here so stimulated him. From the academy he advanced to be teacher of the district school on Corser Hill, in West Boscawen, but after three weeks of pedagogy was obliged to leave on account of sickness. He passed the remainder of the winter in lumbering, rising at 4 A. M. to feed his team of horses. While breakfast was preparing he studied books, ate the meal by candle-light, and then was off with his lunch of cold meat, bread, and apple pie. From the woods to the bank of the Merrimac the distance was three miles, and three or four trips were made daily in drawing the long and heavy logs to the water. Returning home after dark, he ate supper by candle-light, fed his horses, and gave an hour to study before bedtime. The summer of 1844 was one of hard toil on the farm. In July he became of age, and during the autumn worked on his brother-in-law's farm, rising at five and frequently finishing about 9 P. M. It is no wonder that all through his life Mr. Coffin showed a deep sympathy, born of personal experience, with men who are bound down to physical toil. Nevertheless, the fine arts were not neglected. He had already learned to play the "seraphine," the instrument which has been developed into the reed organ. He started the project, in 1842, of getting one for the church. By great efforts sixty dollars were raised and an instrument purchased in Concord. Mr. Coffin became the "organist," and also taught singing in the schoolhouse. Three of his nieces, excellent singers, assisted him. The time had now come for the young man to strike out in the world for himself. Like most New England youth, his eyes were on Boston. With a recommendation from his friend, the minister, he took the stage to Concord. The next day he was in Boston, then a city of 75,000 people, with the water dashing against the embankment of Charles Street, opposite the Common, and with only one road leading out to Roxbury. Sloops and schooners, loaded with coal and timber, sailed over the spot where afterwards stood his house, at No. 81 Dartmouth Street. In a word, the "Back Bay" and "South End" were then unknown. Boston city, shaped like a pond lily laid flat, had its long stem reaching to the solid land southward on the Dorchester and Roxbury hills.