Charles Boys' parents were Caroline Goodrich Dobbie and the Rev Charles Boys who was the vicar at Wing. Charles was one of a large family, being his parents' eighth child, and he was brought up in the vicarage at Wing. He was educated at Marlborough, and in the dedication of his book on Soap bubbles he expressed his gratitude to Mr G F Rodwell, the first science master appointed at that school. From there Boys went to the Royal School of Mines where he was taught physics by Frederick Guthrie. He graduated in mining and metallurgy. The school had no mathematics department so Boys learnt mathematics from books including Todhunter's Integral Calculus. He always claimed, perhaps because of this lack of mathematical education, that he was not a mathematician. Others, including his pupils, certainly did not agree with this as he showed a wide knowledge of geometrical methods.
Boys is famed as a physicist and inventor of instruments. While still at the Royal School of Mines he invented an integraph, a machine for drawing the antiderivative of a function. He published a description of this instrument in the Philosophical Magazine in 1881. After graduating in mining it was natural for Boys to seek employment at a colliery, which he did. After a short time in this employment, Guthrie offered him employment as a demonstrator in physics. He accepted this post and began his academic career.
It was his invention of a fused quartz fibre suspension that brought him great fame, and his applications of quartz fibres are described in  in the following way:-
One application he made of [quartz fibres] was to the suspension of the moving system of his radiomicrometer for the measurement of radiant heat, an instrument so sensitive that, aided by a reflecting telescope to bring the heat to a focus, it could detect the differences in radiation from different parts of the moon's disc and would respond to the heat of a candle at a distance of more than a mile ... He also made use of quartz fibres in his repetition of Cavendish's famous experiment for the determination of the gravitational constant.
It was by using a quartz fibre suspension in Cavendish type experiments that Boys was able to improve the value obtained for the gravitational constant. He used quartz fibres to suspend a short (less than one inch long) beam with spheres at each end. He was then able to use attracting masses much larger in proportion than Cavendish had been able to use, thus enabling him to make accurate measurements of the small forces involved. His work on gravitation is certainly his most important contribution and shows the precision which he could achieve in his experiments. However there were many problems which he had to overcome, such as the vibrations in the earth caused by traffic. To avoid these problems he conducted his experiments in Oxford, rather than London, but he still had to make his measurements at times when no shunting was going on in the railway yards more than a mile from his laboratory. His remarkably accurate results were published in the Philosophical Transactions of the Royal Society in 1895.
Further contributions which Boys made to other areas are also described in :-
Another subject to which he devoted a great deal of attention was the photography of lightning flashes and of rapidly moving objects, such as bullets, and soap films provided him with a study in which his powers of delicate manipulation found full scope, his book on "Soap bubbles, their colours, and the forces which mould them" being a classic in its way.
In 1888 Boys was elected a Fellow of the Royal Society. The following year he became assistant professor at the Royal College of Science, South Kensington, a post he held until 1897. While holding this post he supplemented his income examining for the University of London. He married Marion Amelia Pollock in 1892, and we comment below about how this marriage ended in divorce. They had one daughter and one son.
In 1887 Boys took up an applied science post of Metropolitan Gas Referee and he held this post until the Referees were abolished in 1939. Even then, his services were retained in an advisory capacity until 1943. It was in this role that he worked for many years to improve the instruments used to measure the calorific value of gas. This enabled gas to be priced in terms of its calorific value rather than in terms of its volume.
His (alleged) ill-treatment of his wife led to her having an affair with Forsyth and a scandal at Cambridge resulted. Boys divorced his wife in 1910 after 18 years of marriage. From 1913 onwards he lived in rooms in Westminster, going every weekend to the country where he had a workshop.
After 1939 he retired permanently to his country house where he became interested in growing weeds. He published Weeds, weeds, weeds in 1937.
Boys received many honours in addition to election to the fellowship of the Royal Society which we mentioned above. He received the Royal Medal from the Royal Society in 1896 and from the same Society he received its Rumford Medal in 1924. He was also awarded the Duddell Medal of the Physical Society in 1925, and the Elliot Cresson Medal of the Franklin Institute of Philadelphia in 1939. He was elected to the New York Academy of Sciences and the Physical Society of Moscow. He was knighted in 1935.
Other honours included election to the presidency of the Röntgen Society in 1906-07, of the Mathematics and Physics Section of the British Association in 1903, and of the Physical Society in 1916-17. The University of Edinburgh awarded Boys an honorary degree in 1932.
Article by: J J O'Connor and E F Robertson