Page:Sir William Petty - A Study in English Economic Literature - 1894.djvu/51

52 by laborious conjectures and calculations to deduce the number of people from the births and burials, may be ingenious, but very preposterous." The way to remedy these defects in statistical material he himself pointed out by offering specimen bills which should contain the information he lacked, and he proposed plans for securing more exact information.

It is not necessary to submit Petty's other applications of mathematics to close examination. Among them may be mentioned his estimates of the total wealth in England, of the amount of money necessary to drive the trade of England, of the loss sustained by the Irish rebellion. These and others of like character are of no great scientific value.

A much more interesting matter is Petty's own outline of what the science of statistics should properly include. He is by no means satisfied by mere vital statistics. He makes a strong plea for the collection by the State of exact information on the condition of trade, commerce and agriculture. He was, I believe, the first to recommend the institution of general meteorological observation. As far as possible he tried to remedy the insufficiency of his own information. Aubrey, in his history of Wiltshire, records that at Petty's desire he had collected information on the following heads: Price of corn, rent of land, taxation, poor rates, number of lawyers, fairs and markets.