Such as are desirous of learning any Part of Practical or Theoretical Mathematics may be taught by Isaac Greenwood, A.M. &c. in Clark's Square, near the North Meeting House, where Attendance will be given between the Hours of 9 and 12 in the Forenoon, and 2 and 5 in the Afternoons. N.B. Instructions may also be had in any Branch of Natural Philosophy, when there is a sufficient Number to attend.[33] John Bailey II (1752-1823) of Hanover and Lynn, Massachusetts worked as a clockmaker from about 1770. His father, John Bailey I, and his brothers Calvin and Lebbeus also were clockmakers. Bailey married Mary Hall of Berwick, Maine, and settled in Hanover where he made scientific instruments and clocks. A brass surveying compass in the collection of the New York Historical Society is inscribed "J. BAILEY HANOVER 1804."[34] Undoubtedly the best known instrument maker in Massachusetts was Joseph Pope (1750-1826), of Boston, who was described by contemporaries as the "local mathematician, watch-maker and mechanical genius." In 1787 he completed the construction of a gear-driven orrery displaying the motions of the solar system in a horizontal plane with eccentric and inclined orbits. At each of the twelve corners were mounted cast bronze figures, claimed to have been carved in wood by Simeon Skillin and cast in bronze by Paul Revere. Although the instrument was made for Harvard, the university lacked funds for its purchase. Accordingly, it held a public lottery which realized a substantial sum in excess of the L450.3.0 paid to Pope, and the orrery was delivered in December 1788.[35] The orrery (fig. 18) has survived and is part of the collection of historical scientific instruments at Harvard University. According to a statement in the _Boston Gazette_ for February 16, 1789, an apparatus for displaying planets in their proper orbits by means of wires was made and exhibited in Boston by Bartholomew Burges. Mention must also be made of several members of the Folger family of Nantucket, Massachusetts. Peter Folger (1617-1690), founder of the American branch of the family, emigrated from Norfolk, England, in 1635 and occupied himself in Nantucket as blacksmith, schoolmaster, watchmaker, and surveyor. He was a grandfather of Benjamin Franklin. Another notable descendant was Maria Mitchell (1818-1889), professor of astronomy and director of the observatory at Vassar College.