POLITICAL ARITHMETIC is the art of reasoning by figures upon matters relating to government; such as the revenues, number of people, extent and value of land, taxes, trade, &c. in any nation. These calculations are generally made with a view to ascertain the comparative strength, prosperity, and resources of any two or more nations. With this view, Sir William Petty, in his Political Arithmetic, entered into a variety of calculations concerning the different countries of Europe. With these calculations Dr Davenant was dissatisfied; and, therefore, from the observations of Mr Gregory King, he advanced others of his own. (See his Essay on Trade.) The advancement of society has entirely superseded the calculations of these writers; but their works are deserving of notice, as marking the progress of knowledge in this branch of political science. See the articles INSURANCE, MORTALITY, and STATISTICS.