Such works present us with agreeable and lively pictures of manners. By the vivacity of their descriptions they inflame our natural love of virtue, and increase our abhorrence of vice: by the justness as well as delicacy of their observations they may often help both to correct and to ascertain our natural sentiments with regard to the propriety of conduct, and suggesting many nice and delicate attentions, form us to a more exact justness of behaviour, than what, without such instruction, we should have been apt to think of. In treating of the rules of morality, in this manner, consists the science which is properly called Ethics, a science, which though like criticism, it does not admit of the most accurate precision, is, however, both highly useful and agreeable. It is of all others the most susceptible of the embellishments of eloquence, and by means of them of bestowing, if that be possible, a new importance upon the smallest rules of duty. Its precepts, when thus dressed and adorned, are capable of producing upon the flexibility of youth, the noblest and most lasting impressions, and as they fall in with the natural magnanimity of that generous age, they are able to inspire, for a time at least, the most heroic resolutions, and thus tend both to establish and confirm the best and most useful habits of which the mind of man is susceptible. Whatever precept and exhortation can do to animate us to the practice of virtue, is done by this science delivered in this manner. II. The second set of moralists, among whom we may count all the casuists of the middle and latter ages of the christian church, as well as all those who in this and in the preceding century have treated of what is called natural jurisprudence, do not content themselves with characterizing in this general manner that tenour of conduct which they would recommend to us, but endeavour to lay down exact and precise rules for the direction of every circumstance of our behaviour. As justice is the only virtue with regard to which such exact rules can properly be given; it is this virtue, that has chiefly fallen under the consideration of those two different sets of writers. They treat of it, however, in a very different manner.