Richard Delamain

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Richard Delamain , also Delamaine, (* around 1600 in London ; † 1644/1645 ) was an English engineer , inventor and author .

biography

Very little is known about Delamain's life. He was probably born into a low-class family. In the 1620s he married Sarah, who lived on the upper end of Chancery Lane in London and with whom they had at least eleven children, ten of whom survived their father, including the clergyman Richard Delamaine the Younger (baptized 1627, died 1657). To distinguish it from his son, the father is also called Richard Delamain the Elder.

Delamain was initially a carpenter. However, he attended lectures on mathematics at Gresham College and studied there with Edmund Gunter (1581-1626), the inventor of the so-called Gunters scale, a forerunner of the modern slide rule.

During his time as a student at Gresham College, he worked as a teacher of mathematics and as an inventor of mathematical instruments. Two of these instruments are known through publications: the Grammelogia, a circular slide rule, and the Quadrant.

On May 20, 1633, Delamain was appointed to the Board of Ordnance as an engineer . There he was responsible for building fortresses and building war machines. In 1642, when the Civil War broke out, he took the side of Oliver Cromwell and served in the Parliamentary Army. During this time he was responsible for building fortresses in Northampton, Newport (in Wales) and Abingdon.

In 1645 his widow Delamain applied for support from the House of Lords on the grounds that several children were sick and the funds had been used up. On October 23, 1645, the House of Lords agreed to a boarding house for Sarah, Delamain's widow. Delamain therefore probably died between the summer of 1644 and the spring of 1645.

plant

In January 1631 according to the modern era, contemporary in January 1630, he published his book Grammelogia - or the mathematical ring and a corresponding circular slide rule. This consisted of a fixed disk and a movable ring with logarithmic scales on both, making it the first logarithmic slide rule in the world to be described. Shortly before Christmas 1630 he sent the book to King Charles I with the slide rule, whereupon the king gave him a ten-year monopoly over the instrument. A book on the so-called quadrant was Delamain's second work. For a third book, namely about the fortification, Delamain received on August 4, 1643 the printing permission from the House of Lords. No further information exists about this last book.

The argument with Oughtred

William Oughtred (1574-1660) and his co-author William Forster published the Circles of Proportion in 1632 , in which a circular calculating disk is described that is used with the help of two pointers, similar to the Gunter's scale with compasses. In that book and other writings, Oughtred and Forster claimed that Delamain stole Oughtred's invention of the slide rule. Delamain always denied this. In these letters, Oughtred also provided many details about Delamain's life, making Oughtred the most important primary source on Delaimai's early career alongside Delamain's books.

After several studies, Florian Cajori came to the conviction that the development of Delamain's slide rule was very likely independent of Oughtred and that Delamain must at least be given priority of publication: "We incline to the opinion that the hypothesis of independent invention is the most plausible. At any rate, Delamain figures in the history of the slide rule as the publisher of the earliest book thereon and as an enthusiastic and skillful designer of slide rules. " .

Oughtred's accusation that he had also stolen the quadrant was countered by Delamain with reference to the work of his teacher Gunter and explained how he developed the quadrant on its basis.

The dispute with Oughtred, through which Delamain's academic reputation was massively damaged by Oughtred accusing him of plagiarism, is likely to have been the reason why Delamain mainly worked for the army from 1633 onwards.

literature

  • Florian Cajori : On the History of Gunter's Scale and the Slide Rule during the Seventeenth Century , 1920.
  • EGR Taylor : The mathematical practitioners of Tudor and Stuart England , Cambridge 1954, p. 201
  • HK Higton: Delamain, Richard, the elder (d. 1644?) , Oxford Dictionary of National Biography
  • JF Scott: Delamain, Richard , Dictionary of Scientific Biography , Volume 4, p. 13
  • AJ Turner: William Oughtred, Richard Delamain and the Horizontal Instrument in 17th-Century England , Annali dell'Istituto e Museo di Storia della Scienza di Firenze, Volume 6, 1981, pp. 99-125.

Web links

Individual evidence

  1. ^ Biographical dates according to John J. O'Connor, Edmund F. Robertson: Richard Delamain. In: MacTutor History of Mathematics archive. In the Dictionary of Scientific Biography no exact dates of life are listed, also in the article by Higton in the Dictionary of National Biography only the year of death 1644 with a question mark.
  2. ^ "Master Gunter, Professor of Astronomy in Gresham College (my worthy tutor)" in Delamain: "Grammelogia or the mathematical ring", 1630, To the reader.
  3. ↑ Delamaine's Ordinance. House of Lords, October 23, 1645, accessed May 16, 2020 .
  4. ↑ Richard Delamain: "The making, description and use of a small portable instrument of the pocket called a horizontal Quadrant", London 1632
  5. ^ Delamaine to print a Book of Fortification. House of Lords, August 4, 1643, accessed May 16, 2020 .
  6. ^ Willam Oughtred and William Forster: Circles of Proportions 1632.
  7. ↑ Florian Cajori: On the History of Gunter's Scale and the Slide Rule during the Seventeenth Century, 1920:
personal data
SURNAME Delamain, Richard
ALTERNATIVE NAMES Delamaine, Richard
BRIEF DESCRIPTION English engineer, inventor and author
DATE OF BIRTH around 1600
PLACE OF BIRTH London
DATE OF DEATH 1644