A physician of La Rochelle, France, Elié Richard was a man of science, and a considerable celebrity in his day. He had built, in 1690, a dirigible vehicle that he used to travel about in on his professional work. The carriage was propelled by mechanism operated by a man-servant by means of a treadle. The operator was placed on the rear of the carriage, and the occupant, seated in front, steered by a winch attached to a small wheel. This construction was frequently referred to by contemporaries of Richard, and even later on, and was copied by others during the following hundred years or so. GOTTFRIED WILHELM VON LEIBNITZ Born at Leipsic, Germany, July 6, 1646. Died at Hanover, November 14, 1716. Leibnitz, in addition to his work as a philosopher and mathematician, was also interested in mechanics. He gave some attention to the study of the possibility of making improvements in common road vehicles, and he endeavored to encourage, though without results, his contemporary, Denis Papin. HUMPHREY MACKWORTH Born in 1647. Died in 1727. A celebrated English politician and capitalist, Sir Humphrey Mackworth matriculated at Magdalene College, Oxford, December 11, 1674. He was entered at the Middle Temple, in June, 1675, and called to the bar in 1682. In 1695 he was engaged in developing collieries and copper and smelting works at Melencryddan, near Neath, Wales, and the improvements introduced by him there were of the greatest value. Among other improvements he constructed a wagon-way from the mines, and propelled his coal-carrying cars by sails. DENIS PAPIN Born at Bloys, France, August 22, 1647. Died in England, 1712. Papin was a son and nephew of a physician. He studied medicine in Paris and practiced for some time, attaining distinction in his profession. A passion for the sciences, mathematics and physics drew him away from medical practice and he became skillful in other lines. He followed assiduously the footsteps of Huygens and in some respects became a rival of his master in original thought and experimenting and in professional attainments.