In proportion as the human race grew more numerous, men's cares increased. The difference of soils, climates and seasons, must have introduced some differences into their manner of living. Barren years, long and sharp winters, scorching summers which parched the fruits of the earth, must have demanded a new industry. On the sea-shore and the banks of rivers, they invented the hook and line, and became fishermen and eaters of fish. In the forests they made bows and arrows, and became huntsmen and warriors. In cold countries they clothed themselves with the skins of the beasts they had slain. The lightning, a volcano, or some lucky chance acquainted them with fire, a new resource against the rigours of winter: they next learned how to preserve this element, then how to reproduce it, and finally how to prepare with it the flesh of animals which before they had eaten raw. This repeated relevance of various beings to himself, and one to another, would naturally give rise in the human mind to the perceptions of certain relations between them. Thus the relations which we denote by the terms, great, small, strong, weak, swift, slow, fearful, bold, and the like, almost insensibly compared at need, must have at length produced in him a kind of reflection, or rather a mechanical prudence, which would indicate to him the precautions most necessary to his security. The new intelligence which resulted from this development increased his superiority over other animals, by making him sensible of it. He would now endeavour, therefore, to ensnare them, would play them a thousand tricks, and though many of them might surpass him in swiftness or in strength, would in time become the master of some and the scourge of others. Thus, the first time he looked into himself, he felt the first emotion of pride; and, at a time when he scarce knew how to distinguish the different orders of beings, by looking upon his species as of the highest order, he prepared the way for assuming pre-eminence as an individual. Other men, it is true, were not then to him what they now are to us, and he had no greater intercourse with them than with other animals; yet they were not neglected in his observations. The conformities, which he would in time discover between them, and between himself and his female, led him to judge of others which were not then perceptible; and finding that they all behaved as he himself would have done in like circumstances, he naturally inferred that their manner of thinking and acting was altogether in conformity with his own. This important truth, once deeply impressed on his mind, must have induced him, from an intuitive feeling more certain and much more rapid than any kind of reasoning, to pursue the rules of conduct, which he had best observe towards them, for his own security and advantage.