Henry Gellibrand was born, in London. He ' was of Trinity College in Oxford. Dr Potter and Dr William Hobbes knew him. Dr Hannibal Potter was his tutor, and preached his funeral sermon in London. They told me that he was good for little a great while, till at last it happened accidentally that he heard a geometry lecture. He was so taken with it that he immediately fell to studying it, and quickly made great progress in it. The fine sundial over the College Library is of his own doing. He was astronomy professor in Gresharn College, London. He being one time in the country showed the tricks of drawing what card you touched, which was by combination with his confederate, who had a string that was tied to, his leg, and the leg of the other, by which his confederate gave him notice by the touch; but by this trick he was reported to be a conjuror.
See Canterbury's Doom about Protestant martyrs, inserted in the almanac: he held prayer-meetings in Gresham College.
From John Aubrey's Brief Lives. (Edited by R Barber, Boydell Press, 1982)