accuracy of part of his own reasoning, or thought it prudent to dispel error by covert insinuation of the truth, rather than by an open attack on the front of the hostile position, and to leave some loophole to his antagonists, and some means of retreat to himself. Unlike his brother physician and economist in the following century, Quesnay, with whom a comparison suggests itself, his mind was essentially practical. He would probably have preferred the relaxation of the fetters of Irish trade, even of a partial character, to any amount of proclamations of abstract economic truth. Quesnay, sheltered by the silence and security of a royal palace, elaborated a deductive system, and pushed it, with the pitiless logic characteristic of his countrymen, to the most extreme conclusions, and then left it there to blossom or to wither as might happen. Sir William Petty wrote in order to influence the political conduct of the men amongst whom he lived and moved; he expressed himself 'in terms of number, weight, and measure;' he used only 'arguments of sense, and such as rested on visible foundations.'[1] He had to battle with principalities and powers; to be closeted with politicians ignorant of the very elements of commercial policy, but able at any moment to silence him; and to persuade kings more open to flattery than to argument,
qui sciret regibus uti
Fastidiret olus,
is the maxim which, with almost cynical frankness, he placed at the head of one of his essays on Political Arithmetick;[2] and at no time would he probably have thought it worth his while to press for more than there was an actual chance of obtaining, or to injure his own case by indiscreet advocacy. 'Men of great office in England,' he said, 'are so mutable and slippery, as that they spend their whole time and thought in securing themselves, and dare not employ others than creatures and confederates under themselves.'[3]
