Transcribed from the Cassell & Co. edition ,
ESSAYS ON MANKIND AND POLITICAL ARITHMETIC
INTRODUCTION.
William Petty, born on the 26th ofMay, 1623, was the son of a clothier at Romsey inHampshire. After education at the Romsey Grammar School, hecontinued his studies at Caen in Normandy. There hesupported himself by a little trade while learning French, andadvancing his knowledge of Greek, Latin, Mathematics, and muchelse that belonged to his idea of a liberal education. Hisidea was large. He came back to England, and had for ashort time a place in the Navy; but at the age of twenty he wentabroad again, and was away three years, studying actively atUtrecht, Leyden, and Amsterdam, and also in Paris. In Parishe assisted Thomas Hobbes in drawing diagrams for his treatise onoptics. At the age of twenty-four Petty took out a patentfor the invention of a copying machine. It was described ina folio pamphlet “On Double Writing.” That wasin 1647, in Civil War time, and although Petty followed Hobbes inhis studies, he did not share the philosopher’s politicalopinions, but held with the Parliament. In 1648 he added tohis former pamphlet a “Declaration concerning the newlyinvented Art of Double Writing.”
Samuel Hartlib, the large-hearted Pole, who in those daysspent his worldly means in England for the advancement ofagriculture and of education, and other aids to the well-being ofa nation, had caused Milton to write his letter on education, ashas been shown in the Introduction to the hundred andtwenty-first volume of this Library, which contains that Lettertogether with Milton’s Areopagitica. YoungPetty’s first published writing was a Letter to Hartlib onEducation, entitled “The Advice of W. P. to Mr. SamuelHartlib for the Advancement of some Particular Parts ofLearning.” This appeared in 1648, when Petty’sage was twenty-five, and its aim was to suggest a wider view ofthe whole field of education than had been possible in the MiddleAges, of which schools and colleges were then preserving thetraditions, as they do still here and there to some extent. This pamphlet has been reprinted in the sixth volume of the“Harleian Miscellany.” William Petty wished thetraining of the young to be in several respects morepractical.
His own activity of mind caused him to settle at Oxford, wherehe taught anatomy and chemistry, which he had been studyingabroad. He had read with Hobbes the writings of Vesalius,the great founder of modern practical anatomy. In 1649William Petty graduated at Oxford as Doctor of Medicine, obtaineda fellowship at Brasenose, and practised. In 1650 hesurprised the public by restoring the action of the lungs in awoman who had been hanged for infanticide, and so restoring herto life.
Dr. Petty now took his place at Oxford among the energetic menof science who had been inspired by the teaching of Francis Baconto seek knowledge by direct experiment, and to value knowledgeabove all things for its power of advancing the welfare ofman. The headquarters of these workers were at Oxford, andin London at Gresham College.
In 1650 Petty was made Professor of Anatomy at Oxford, and itis a characteristic illustration of his great activity of mindthat he was at the same time Professor of Music at GreshamCollege. Music had then a high place in the Seven Sciences,as that use of regulated numbers which expressed the harmonies ofthe created world. The Seven Sciences were divided intothree of the Trivium, and four of the Qu