Escaping his family and anything smacking of civilization, he chose a lonely, rocky cliff in Maine overlooking the ocean. There he built himself a studio in which he lived for most of the rest of his life. He liked the sea. He traveled north into Canada and to the tropics in the winter. And he found the perfect medium for his nomadic sojourns--the fledgling art of watercolor. Though he didn't exactly "invent" the medium, he made it so much his own, his name is practically synonymous with this artform. Until Homer adopted it, watercolor had been largely the medium of color sketches--preparatory studies for studio landscapes rather than a medium for finished work. Although a few English artist had used it for years as a means of "coloring" architectural drawings, before Homer, it had largely been considered little more than an artistic novelty for young ladies to "play" with.
Homer often traveled deep into the Canadian wilderness with paid guides whom he astounded by paying them to pose for him--fishing, sleeping, eating, rowing, shooting rapids--all while he sat on the bank and drew them, rapidly, pencil flying, paper strewn all about his feet, dashing off one incomplete drawing after another. These he assembled in his tent on rainy days when he painted, often turning out a dozen or more watercolor sketches at a time, some of which would later be turned into finished oil paintings. It's believed that even Homer didn't originally approach watercolor as a medium for finished works until later in his life when they became popular with local residents in the coastal nooks and crannies where he chose to paint. Whatever the case, he wrote the book that made this medium what it is today.