# Samuel Molyneux

### Quick Info

Born
18 July 1689
Chester, Cheshire, England
Died
13 April 1728
Kew, Surrey, England

Summary
Samuel Molyneux was an English astronomer who produced some new telescope designs.

### Biography

Samuel Molyneux's father was William Molyneux, a notable Irish astronomer and politician, and his mother was Lucy Domville, the youngest daughter of Sir William Domville, the attorney-general for Ireland. William and Lucy had married on 19 September 1678 but Lucy had been struck down by an illness two months after the marriage and she became blind living in pain for the rest of her life. Samuel was born in Chester in England since his parents had left Dublin in January 1689 anticipating the political problems which arose in Ireland after the Roman Catholic James II, King of the United Kingdom, was deposed. The Molyneux family were Protestants and they remained in Chester until James, who had led an army in Ireland, was defeated at the Battle of the Boyne in 1690. Samuel never knew his mother for, after she returned to Dublin with him in January 1691, she only lived until May of that year.

Samuel's father, William Molyneux, began to correspond with the English philosopher John Locke beginning in 1692. Locke had written Some thought concerning education (1693) which was based on a series of letters he had written to Edward Clarke from Holland (where he had been in exile) advising him on how to bring up his son. This, of course, was now a topic of great interest to William Molyneux and he enthusiastically followed Locke's ideas in bringing up Samuel. However, William died in 1698 when Samuel was only nine years old, and from that time on he was brought up by his uncle Thomas Molyneux. When he was sixteen years old, Samuel Molyneux matriculated at Trinity College, Dublin and there he became friendly with George Berkeley who was four years his elder. Berkeley clearly had great respect for Molyneux, both as a man and as a scientist, and dedicated Miscellanea mathematica (1707) to his friend who was still an undergraduate at this time. He graduated with a B.A. in 1708 and, two years later, received his M.A. from Trinity College.

On the death of his father, Molyneux had inherited an estate at Castle Dillon in County Armagh in Ireland which brought in a good income and, after leaving Trinity College, he spent two years making improvements to the estate. In 1712 he visited England and in that year was elected to the Royal Society of London. He continued his travels going next to Antwerp where he spent the winter of 1712-13. There he met the Duke and Duchess of Marlborough who asked him to undertake a diplomatic mission to the court of Hanover. He carried out this mission and was at the court of Hanover when the Electress Sophia died on 8 June 1714 making her son Georg Ludwig, elector of Hanover, heir to the throne of the United Kingdom. Queen Anne died on 1 August 1714 and Georg Ludwig became King George I of the United Kingdom. Molyneux accompanied the new king and his family back to London where he was made secretary to George's son, the Prince of Wales. This was a position which Molyneux retained until the Prince became King George II, on the death of George I, on 11 June 1727.

They purchased a George Graham zenith sector, strongly built of soldered tin plate, with a radius of twenty-four feet, an arc of 25 arc minutes, and a vernier scale that showed arc seconds. It was mounted in November 1725 at Molyneux's home on Kew Green, by boring holes through the ceiling and roof. A zenith sector swivels at the objective end, and an iron frame was attached to the chimney to mount the objective and suspend the tube. The eyepiece was $3\large\frac{1}{2}\normalsize$ feet above the floor. The position of Gamma Draconis was observed over four nights between December 3 and 12, without any measurable change in position.
In fact they showed that Hooke was wrong and, having failed to measure the parallax of Gamma Draconis, they at least had shown that Hooke's value for the parallax was incorrect. In fact it would be more than 100 years later before Wilhelm Bessel made the first successful measurement of the parallax of a star.

On his death Molyneux had around 700 instruments, mostly for astronomical use. Some of these had been inherited from his father William Molyneux.

### References (show)

1. Biography by A M Clerke, rev. Anita McConnell, in Dictionary of National Biography (Oxford, 2004). See THIS LINK.
2. Biography in Encyclopaedia Britannica. http://www.britannica.com/biography/Samuel-Molyneux
3. P Abrahams, When an Eye is armed with a Telescope: The Dioptrics of William and Samuel Molyneux. http://www.europa.com/~telscope/molyneux.txt
4. C Molyneux, An account of the family and descendants of Sir Thomas Molyneux (1820), 32-40.
5. R H Scott, History of the Kew Observatory, Proc. Roy. Soc. London 39 (1885), 37-86.

### Additional Resources (show)

Other pages about Samuel Molyneux:

Other websites about Samuel Molyneux:

Written by J J O'Connor and E F Robertson
Last Update December 2008