Dr. Franklin was annually elected president of the society, Dr. Thomas Cadwalader officiating during his residence abroad. Brissot de Warville, coming to Philadelphia in 1788, exclaims, with devoutness rare in a Frenchman, “Thanks be to God, he still exists! This great man, for so many years the preceptor of the Americans, who so gloriously contributed to their independence; death had threatened his days, but our fears are dissipated, and his health is restored.” Two years later the same chronicler records, “Franklin has enjoyed this year the blessing of death, for which he waited so long a time.” As president of the Philosophical Society, he was succeeded, in 1791, by Dr. Rittenhouse, the greatest American astronomer, of whom Jefferson said, “We have supposed Rittenhouse second to no astronomer living; in genius he must be first, because he is self-taught.” It was he who contributed to the society the first purely scientific paper in its series of Transactions, a calculation on the transit of Venus. He also described a wonderful orrery, which represented the revolution of the heavenly bodies more completely than it had ever been done before, and which he had himself constructed at the age of twenty-three. In June, 1769, he made observations on the transit of Venus. “The whole horizon was without a cloud,” says Rittenhouse, in his report of this event; and so greatly excited was the young astronomer that, in the instant of one of the contacts of the planet with the sun, he actually fainted with emotion. Rittenhouse’s interesting report on this phenomenon, which had never been seen but twice before by any inhabitant of the earth, was received with satisfaction by learned and scientific men everywhere. Those who visit the hall of the society to-day may look out upon the State-House yard from the same window through which Rittenhouse made his observations, and note the passing hours upon the face of a clock constructed by his hands, which, the curator says, “still keeps good time.”