Page:William Petty - Economic Writings (1899) vol 1.djvu/49

Rh vast results that have flowed from his "Estimate of the Degrees of Mortality of Mankind" predispose us to regard as authoritative anything that he may have said as to the work of his predecessors. It should be remembered, however, that Halley was a much younger man than Petty and did not become a member of the Royal Society until five years after Graunt's death. His famous memoir begins with these words:

The contemplation of the mortality of mankind has, besides the moral, its physical and political uses, both which have some time since been most judiciously considered by the curious Sir William Petty, in his moral and political Observations upon the Bills of Mortality of London, owned by Captain John Graunt. And since in a like treatise on the Bills of Mortality of Dublin.... But the deductions from those bills of mortality seemed even to their authors [sic] to be defective.

Bishop Burnet, the fourth of Petty's contemporaries to assert his authorship of the Observations, had no such interest in them as did Halley; indeed his allusion to the subject is merely casual. In the first volume of his "History of his own Time," published in 1723, but probably written before 1705, he makes the charge that Graunt, being a member of the New River Company, stopped the pipes at Islington the night before the London fire, September 2, 1666. Burnetts account of this alleged occurrence begins: "There was one Graunt, a papist, under whose name Sir William Petty published his observations on the bills of mortality."

Such is the direct testimony for Petty. The direct testimony in favour of Graunt comes from five sources. First, from the work whose authorship is in issue. Four editions of the "Observations" published during his lifetime and one published by Petty after Graunt's death, all bear on their title-pages Graunt's name as author. Second, Petty's own testimony in his books and in his private correspondence. In his acknowledged writings he mentions the Observations at least seventeen times. In nine of these instances Graunt's name is mentioned, in seven he is not named, and in the remaining case, the "Political Arithmetick," as printed in 1690, makes Petty speak of "the observators upon the bills of mortality."