Telescope and lenses, 1787.
© Science Museum / Science & Society Picture Library
Circular sliders (Figs 1 & 2); internal tubes of the telescope (Fig 3); the telescope cover (Fig 4); exterior tube of the telescope (Fig 5); mirror (Fig 6); three lenses of different foci (Fig 7); three lenses of different magnifying powers (Fig 8). Illustration from 'Essays on the microscope' by George Adams (1750-1795), published in London in 1787. Adams was instrument maker to King George III.