Posted by: Footler PJ24 NOV 2011
John Dollond was born in London in 1706, the son of a Huguenot silk weaver. He followed his father’s trade initially but in 1752 joined his son Peter in making optical instruments. His name is often linked with the discovery of the achromatic lens to reduce chromatic aberration (colour defects). However, although he was the first to patent the device he did not discover how to make an achromatic lens.
The problem of chromatic aberration had been debated since the first telescope was made around 1608. Sir Isaac Newton (1642–1727) believed that achromatic lenses were impossible, since he thought that light consisted of distinct particles of different sizes with immutable refractive properties.
However, Chester More Hall (1703–71), a barrister and amateur mathematician, believed that if the eye itself acted as an achromatic lens it should be possible to make one. He experimented with different types of glass until in 1730 he had the correct combination of flint and crown lenses.
Although Hall later appeared unconcerned by priority claims, he did try to keep his discovery secret by using two different firms to make his lenses. Unfortunately for him, they both subcontracted to the same lens maker, George Bass, who realised its significance.
It is thought that Dollond learned the secret of making achromatic lenses from Bass and after patenting the design himself made his fortune with its commercial production. His patent was contested, but his rights were upheld as the court decided that he had developed the idea and brought the product to market. Later, he received a medal from the Royal Society and was appointed optician to King George III and the Duke of York.
John Dollond died 250 years ago on 30 November 1761. In 1927 Dollond & Co merged with Aitchison & Co to become Dollond & Aitchison, which in turn was merged into Boots Opticians in May 2009.