Automatic pan balance, 1964.
© Science Museum / Science & Society Picture Library
This oertling pan balance can give the weight in grammes down to the third decimal place. A graticule attached to the balance arm is magnified by an optical system and projected on a scale, the displacement of the graticule from zero when the balance comes to rest gives the fourth decimal place. Ludwig oertling, who designed this type of balance, settled in London in the early 1850s and his firm became the leading manufacturer of balances in Britain.