The sketch of Wren’s activities at Wadham (in Chapter II) shows the variousness of his mind, but clearly his many inventions, though they make an astonishing list, were _juvenilia_. His contemporary Hooke said of him, “Since the time of Archimedes there scarce ever met in one man in so great perfection such a mechanical hand and so philosophical a mind”; and he describes a method of determining the parallax of comets “invented by that incomparable mathematician Dr. Christopher Wren.” In estimating the value of such an opinion, one of very many, I am bound to rely on the judgment of scientific friends who have generously helped me with this chapter, because I can only repeat Professor Lethaby’s comment on the same text: “These things are beyond my knowledge, but I know that they represent wonderful powers.” We shall only understand the part played by Wren in the development of natural science if we see that development as the work of a team rather than of individuals. Wilkins, Boyle, Lawrence Rooke, Hooke, Seth Ward, Wallis, Scarborough, Oughtred, Wren and many another shared a common enthusiasm for the advancement of knowledge which showed itself in common effort. Wren was the man to whom his associates turned for help in solving their individual problems, because of his extraordinary ingenuity in inventing apparatus which would establish or dispel the truth of some scientific idea, and still more because of his ready kindness and modesty. During the early days of the Royal Society he was not only in an especial manner the cement which kept together the whole fabric, but the inspirer of much work which was carried to fruition by others. In 1645, the year when Wren invented, as a boy of thirteen, a new astronomical instrument, the first meetings took place at which was sown the seed from which the Royal Society sprang. Dr. Wallis, the mathematician, Dr. Goddard, Wilkins, later Warden of Wadham, and Sir Christopher’s father, Dr. Wren, were amongst the attendants at weekly gatherings, when philosophy and especially natural science were discussed. When Wallis, Wilkins, and Goddard went to Oxford in 1648-49, the London meetings continued, but new meetings were held also at Oxford, first in Dr. Petty’s rooms and afterwards at the apartments of Wilkins at Wadham. When Wilkins went to Trinity, Cambridge, the Oxford men enjoyed the hospitality of Robert Boyle.