Dictionary of National Biography, 1885-1900/Arnold, John
ARNOLD, JOHN (1736?–1799), an eminent mechanician and one of the first makers of chronometers in this country, was born at Bodmin in 1736, and not in 1744, as is generally given; his tombstone in Chislehurst churchyard positively states that he died in 1799, ætat. 63. He was apprenticed to his father, a watchmaker in Bodmin, but a quarrel with him led to his going to Holland. In that country he is said not only to have acquired most of his knowledge of watchmaking, but to have learned German, a language which was afterwards of much use to him at court. Leaving the Hague, he came to England, and appears to have made a scanty living as an itinerant mechanic. By the help of a gentleman who was struck with, his mechanical powers, he was enabled to set up in business in Devereux Court, Strand, whence he afterwards removed to the Adelphi. He was introduced at court, and received assistance from King George III towards the cost of his experiment. Afterwards he presented the king with a very curious and very small watch, set in a ring. A full account of this ingenious toy is given in Wood's 'Curiosities of Clocks and Watches,' p. 327. The chronometer of Harrison had not long before Arnold's establishment in London been perfected, and had received the reward offered by parliament for a method of ascertaining the longitude at sea; Arnold took up the manufacture of chronometers (first so named by him), and, besides introducing certain improvements in them, he so systematised the arrangements for their production that he was able to reduce very considerably their originally high price. He made chronometers not only for the government, but also for the East India Company, then a still better customer than the government. Without going into technicalities, it would be impossible to describe Arnold's improvements in the chronometer; they are, however, set out very fully in the article on the chronometer in Rees's 'Encyclopaedia.' The chief improvements with which he is credited are the expansion balance, the detached escapement, and the cylindrical balance spring. All these, however, have been claimed for Earnshaw, and how much of the credit is due to each of the two rivals cannot be said. After Arnold's death the Board of Longitude, which had granted various sums to him during his life, awarded to his son, J. R. Arnold, and to Earnshaw amounts which, with the former grants, made up 3,000l. apiece to each inventor.
[There is a very full account of Arnold in the Biographical Dictionary commenced by the Useful Knowledge Society; a short account of him, with a full list of authorities, is given in Boase and Courtney's Bibliotheca Cornubiensis, iii. 1034; for his improvements in the chronometer see Rees's Cyclopædia, s.v.; Frodsham on the Marine Chronometer; also Arnold's own Works and his two Patent Specifications (No. 1113. A.D. 1775, and No. 1328, A.D. 1782).]