A beautiful vintage Parallel Rule for navigational use from the 1930s. This piece is stunning, and in good condition. A lot of his instruments are now found in many museums: W H Harling - Mathematical Instrument Maker since 1851. In 1851 Harling founded the firm at 47 Finsbury Pavement, London.
They specialised in making drawing instruments, with a factory at Grosvenor Works, Hackney, London EC.
W: 41 x D: 10 x H: 4.5cm