Most of the arts and professions in a state,' says by far the most illustrious philosopher and historian of the present age, 'are of such a nature, that, while they promote the interests of the society, they are also useful or agreeable to some individuals; and, in that case, the constant rule of the magistrate, except, perhaps, on the first introduction of any art, is, to leave the profession to itself, and trust its encouragement to the individuals who reap the benefit of it.