Cylinder electrical machine made by E. Palmer, London, after 1838
The object in the portrait of David Wiley is a cylinder electrical machine, a form that originated in the 1740s and remained popular through the first half of the nineteenth century. When the glass cylinder is rotated and rubbed against a cushion of leather, an electrical charge is generated. Title image: Gregorian reflecting telescope made in London by James Short for John Winthrop/Courtesy Collection of Historical Scientific Instruments, Harvard University, Cambridge Massachusetts |