Middleton Life: Profile of scientist William Gascoigne

William Gascoigne
Gascoigne's micrometer, as drawn by Robert Hooke
Leeds writer Mick McCann writes about one of South Leeds’ most important sons Middleton scientist William Gascoigne for the Middleton Life local history project, which encourages local people to become community history reporters. Mick wrote How Leeds Changed the World, among others…

Gascoigne (1612–1644) was one of the founding fathers of British research astronomy and intellectual heir of Galileo and Kepler whose work he improved upon.

It appears that he died in his early thirties (although earlier accounts make his life much shorter) or who knows what else he would have achieved.

His formal education was limited but he was an astronomer, inventor, mathematician and designer/maker of scientific instruments from Middleton who invented the micrometer (1641), telescopic sextant, and the telescopic sight.

The relatively newly invented telescope was hugely improved and astronomy leaped forward with Gascoigne’s micrometer which allowed angular distances to be accurately measured and was central to astronomical measurement up until the twentieth century.

Adding this to a sextant allowed the measurement of the distance between astronomical bodies. His introduction of crosshairs allowed the telescope to be pointed even more accurately and the fact that they were moveable across the lens gave unprecedented accuracy to the measurement of the size of astronomical bodies – using the pitch of the screw and the focal length of the lens. He was the first man to be able to accurately calculate the size of planets.


His invention of the crosshairs (telescopic sight) happened by pure chance. He was recreating one of Kepler’s optical set-ups when a thread of spider’s web became caught between the two lenses. By chance, it fell precisely at the combined optical focal points of the two lenses and Gascoigne, seeing the web sharp and clear through the lenses (as well as the object being looked at) realised that the accuracy of the telescope was greatly increased by the use of the web as a guide. He increased the accuracy even further by introducing the other line of the cross meaning that the focal point could be centred on an object thus creating the telescopic sight.

He was one of “nos Keplari” a group of astronomers in the north of England who followed the astronomy of Johannes Kepler which included Jeremiah Horrocks and William Crabtree.  

Crabtree and Horrocks were amazed by and giddy with anticipation at Gascoigne’s inventions. Unfortunately Horrocks never got to use them. This hugely influential and impressive trio compiled, for themselves and probably intended for future publication, a series of ground breaking papers which they entitled De re Astronomica, which were passed onto the Townleys family, who chronicled much of their work and then to William Derham who produced the earliest, reasonably accurate, estimate of the speed of sound.

Many of Gascoigne’s papers and correspondence were lost during the English Civil War and then the Great Fire of London, but most of what is known to remain is kept in the Bodleian Library at the Universityof Oxford. John Flamsteed (the first Astronomer Royal) saw Horrocks, Crabtree and Gascoigne as the founding fathers of British research astronomy.

Gascoigne fought for King Charles I (see Red Hall) against the Parliamentarians and died in the Battle of Marston Moor.

At the time of his death he had at his father’s residence, New Hall, Middleton, ‘a whole barn full of instruments,’ constructed by him, to carry out ideas which, unfortunately, died with him.

Accepting the mid-nineteenth century correction to Gascoigne’s age at the time of his death, (raising it from early 20s to around 31/2 years old – unlike Galileo and Kepler, who lived until around 60 and 77 respectively) this still early death leaves me wondering what the barn full of instruments were designed for, what else he would have discovered and invented and how else he would have changed our knowledge of the world and universe and our interaction with it.

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