Page:Life of Sir William Petty 1623 – 1687.djvu/247

 will be divided into as many parts as possible, whereby the work of each artizan will be simple and easie; as for example in the making of a watch, if one man shall make the wheels, another the spring, another shall engrave the Dial plate, and another shall make the case, then the watch will be better and cheaper than if the whole work be put upon any one man. And we also see that in towns and in the streets of a great town, where all the inhabitants are almost of one trade, the commodity peculiar in those places is made better and cheaper than elsewhere.' He distinguishes between productive and unproductive labour, contrasting two classes of men: the first who produce material objects, or things of real use and value, or, in other words, which increase 'the gold, silver and jewels of the country by trade and arms;' the other who 'do nothing at all but eat, drink, sing, play and dance,' to whom he maliciously adds 'such as study the metaphysicks or other needless speculation.' The Essays also show that he understood, at least partially, the principles underlying the laws of supply and demand in their effect on value. Distinguishing between what he terms 'intrinsic' and 'extrinsic' value in a dialogue on the price of diamonds, 'I will first take notice,' he says, '1. that the dearness and cheapness of diamonds depends upon two causes; the one intrinsic which lies within the stone itself, and the other extrinsic and contingent, such as are the prohibitions to seek for them in countries from whence they come.2. When merchants can lay out their money in India to more profit upon other commodities, and therefore do not bring them.3. When they are brought, upon fear of wars, to be a subsistence for exiled and obnoxious persons.4. They are dear near the marriage of some great person when great numbers of persons are to put themselves in splendid appearance. For any of these causes, if they be very strong upon any part of the world, they operate on the whole. For if the price of diamonds should rise in Persia, it shall also perceptibly