He was not to be a poet--that was too definitely bound up with the past which he wanted to forget, and with conventionalities which he wished to shake off; not to be an artist, strugging with the rest to please a public which he felt himself called upon to teach; not a man of science, for his botany and geology were to be the means, and not the ends, of his teaching; but the mission was laid upon him to tell the world that Art, no less than other spheres of life, had its Heroes; that the mainspring of their energy was Sincerity, and the burden of their utterance, Truth..