The latest in the occasional series of history features by Susan Yates, chair of Thurrock Historical Society.

FRESH from recently attending the unveiling of a memorial plaque to a prominent clergyman, Rev John Newton, and writing about his life, Susan Yates has turned her attention to another prominent Reverend gentleman who had a notch on the timeline of history.

Sue writes:- 

While attending Thames Chase recently I heard two gentlemen arguing over who discovered the speed of sound and where it was measured. 

The first man was adamant it was St Laurence Church, Upminster, and the other was convinced it was St Mary Magdalen Church, North Ockendon. This immediately aroused my interest and I made a mental note to find out more about it when I returned home.

My research uncovered the Reverend William Derham who was not just an English clergyman but a philosopher, botanist and scientist too and produced the earliest reasonably accurate measurement of the speed of sound. 

William was born in Stoulton, Worcestershire on 26^th November 1657 the son of Thomas Derham. 

He was educated at Blockley Gloucestershire. His was a poor family but William was very bright and went to Trinity College, Oxford in 1675. He obtained his Batchelor of Arts degree in 1679 and the college's president was so impressed with young William that he introduced him to the Bishop of Salisbury who encouraged him to take holy orders. His first living was at Wargrave, Berkshire in 1682. 

It was on 17th January 1684 that William obtained his marriage licence for his wedding to Isabella Darrell of Kingsclere. 

Sadly, she died in 1695 and was buried on 28^th September 1695 at St. Laurence's Church, Upminster where William was Rector from 31^st August 1689, the living was presented to him by Mrs. Jane Bray, but such was the state of the Rectory at that time that he lived in High House, Corbets Tey Road, which was opposite the church, until his demise in 1735. 

In 1699 he remarried at Upminster. 

His second wife was Anna Scott of Woolston Hall, Chigwell with whom he had three daughters and two sons. 

His son William born in 1702 sadly died at St. John's College, Oxford in July 1757. William was Chaplain to George Prince of Wales and at the age of 59 in 1716 he was created Canon of Windsor and he divided his time between Windsor and Upminster from then on. In 1730 Oxford University conferred on William the honorary degree of Doctor of Divinity by Diploma.

Reverend William Derham

William became famous because in 1709 he discovered a more accurate measure of the speed of sound. 

He calculated that it travelled at 1,072 Parisian feet per second. 

A Parisian foot is an archaic measurement of length equivalent to 1.06575 modern feet or 324.84mm. 

He did this by having a friend fire a shotgun at Woolwich 12 miles away as the crow flies. He used a telescope to watch from a door on the south side of the tower at St Laurence's Church, Upminster.

William Derham Memorial Plaque, St. Laurence's Church Upminster.

He measured the time from when he saw the flash of the gun until he heard the sound of the shot. He carried out the same experiment with gunshots fired from St Mary Magdalen Church, North Ockendon and from Belhus Park. 

This information enabled him to calculate the speed of sound. 

William mixed with many of the greatest minds of the day including John Ray botanist of Black Notley and Sir Isaac Newton

William died on 5^th April 1735 at Upminster and is buried at St. Laurence's Church but the exact location is not known as he did not want any memorial.