In this same year Robert Boyle, then an eager student of eighteen just returned to England from residence abroad, came under the influence of the genial Hartlib. In 1646 he writes his tutor inquiring about books on methods of husbandry and referring to the new philosophical college, which valued no knowledge but as it had a tendency to use. A few months later he was in correspondence with Hartlib in reference to the Invisible College, and had written a third friend that the corner-stones of the invisible, or, as they termed themselves, the philosophical college, did now and then honor him with their company. These philosophers whom Boyle entertained, and whose scientific acumen, breadth of mind, humility, and universal good-will he found so congenial, were the nucleus of the Royal Society of London, of which, on its definite organization in 1662, he was the foremost member. They had begun to meet together in London about 1645, worthy persons inquisitive into natural philosophy--Wilkins, interested in the navigation of the air and of waters below the surface; Wallis, mathematician and grammarian; the many-sided Petty, political economist, and inventor of a double-bottomed boat, who had as a youth of twenty studied with Hobbes in Paris in 1643, and in 1648 was to write his first treatise on industrial education at the suggestion of Hartlib, and finally make a survey of Ireland and acquire large estates; Foster, professor of astronomy at Gresham College; Theodore Haak from the Pfalz; a number of medical men, Dr. Merret, Dr. Ent, a friend of Harvey, Dr. Goddard, who could always be relied upon to undertake an experiment, Dr. Glisson, the physiologist, author in 1654 of a treatise on the liver (_De Hepate_), and others. They met once a week at Goddard's in Wood Street, at the Bull's Head Tavern in Cheapside, and at Gresham College. Dr. Wilkins, the brother-in-law of Cromwell, who is regarded by some as the founder of the Royal Society, removed to Oxford, as Warden of Wadham, in 1649. Here he held meetings and conducted experiments in conjunction with Wallis, Goddard, Petty, Boyle, and others, including Ward (afterwards Bishop of Salisbury) interested in Bulliau's Astronomy; and the celebrated physician and anatomist, Thomas Willis, author of a work on the brain (_Cerebri Anatome_), and another on fevers (_De Febribus_), in which he described epidemic typhoid as it occurred during the Civil War in 1643.