in 1686, that a preliminary essay ‘On the Growth and Encrease and Multiplication of Mankind’ (to which reference is made) was not to be found; but he prefixes a syllabus or ‘extract’ of the work, as supplied by a correspondent of the author. Distinct from both these essays were ‘Two Essays in Political Arithmetick, concerning the People, Housing, Hospitals, &c., of London and Paris … tending to prove that London hath more people than Paris and Rouen put together,’ which appeared, simultaneously with a French translation, in 1686. Various objections raised to the conclusions here arrived at were answered by Petty, in the following year, in his ‘Five Essays in Political Arithmetick,’ a brief pamphlet, printed in French and English on opposite pages (London, twice 48 pp. 8vo). About the same time appeared ‘Observations upon the Cities of London and Rome’ (London, 1687, 8vo). This group of essays is completed by ‘Political Arithmetick, or a Discourse concerning the extent and value of Lands, People, Buildings; Husbandry, Manufacture, Commerce, Fishery, Artizans, Seamen, Soldiers; Public Revenues, Interest, Taxes …’ (London, 1690, 8vo), dedicated to William III by the author's son ‘Shelborne.’ This work, written by Petty as early as 1676 or 1677, but refused a license as likely to give offence in France, had nevertheless been printed, doubtless without Petty's consent, in 1683. It then appeared in the form of an appendix to J. S.'s ‘Fourth Part of the Present State of England,’ 1683 (a spurious continuation of Chamberlayne), under the separate title ‘England's Guide to Industry; or, Improvement of Trade for the Good of all People in General … by a person of quality’ (The only perfect copy known of this unauthorised edition is in the Bodleian Library.).
All these works may be said to belong to what, in modern days, has been called the inductive school of political economy, though they contain some instances of purely deductive reasoning, e.g. a speculation on ‘a par of land and labour,’ which occurs in the ‘Treatise of Taxes’ (ch. iv.). In the reign of Charles II the whole system of administration and finance was passing through a period of transition. The old ‘prohibitory’ school, the ideas of which were aimed against the export of the precious metals, was dying, and the ‘mercantile’ system was struggling into its place. This system sought to develop trade, but to regulate it with a view to encourage the import of the precious metals into the country. Petty saw clearly the folly of the prohibitory system, and his acute mind having analysed the sources of wealth as being labour and land, and not the mere possession of the precious metals, he went very near to arriving at a correct theory of trade. On the one hand, he had before him the example of Holland, which approached more nearly to being a free port than any other country, levying its taxation by a general excise on all articles of consumption; and, on the other, the example of France, which, under Colbert, was beginning the commercial legislation which was soon to involve Europe in a prolonged war of tariffs. Petty decided in favour of the example of Holland. But he nevertheless still believed that there was some inherent superiority in the precious metals over other articles of wealth, and seems to contemplate that, under possible circumstances, it might be necessary to check the importations exceeding the exportations, in order to prevent the precious metals from leaving the country. On the other hand, he condemned elsewhere attempts ‘to persuade water to rise of itself above the natural spring’ (Treatise on Taxes, ch. vi.; Pol. Arith. ch. i. 224, ii. 235), and many similar expressions condemnatory of interference with the natural course of exchange.
Besides his correct analysis in the ‘Treatise of Taxes’ of the origin of wealth, which is one of Petty's principal titles to fame, passages in his various works show that he had clearly grasped the importance of the division of labour, and of the multiplication of wealth proceeding pari passu with the increase of population; that he understood the folly of laws against usury; the nature of exchange; and the reasons why the precious metals are the best measure of value, though he involved himself in a hopeless attempt to find a ‘par of value’ for the precious metals as well as for other commodities. The ‘Political Anatomy of Ireland’ is an able description of the land and people of the country, and analyses the best means of developing its resources. The hostile commercial policy of the English parliament made Petty a strong partisan of a union between the two countries as the only means of preventing the natural industries of the smaller island being struck down by her jealous and selfish neighbour, and thus confirmed the natural leaning of his mind in the direction of unrestricted trade. He was a strong partisan of religious freedom, and here again found reasons in support of a union, as he believed that only by this means could the Roman catholics of Ireland, if admitted to power, be prevented from persecuting the protestants; while, on the other hand, he thought it desirable to strengthen the Roman catholic interest in
