Richard Delamain

Richard Delamaine or Delamain, known as the elder (before 1629- before 1645), was an English mathematician, known for works on the circular slide rule and sundials.

His earliest published work Grammelogia was dedicated to Charles I. It was attacked in William Oughtred's Circles of Proportion (1631), on grounds of plagiarism: Oughtred had taught Delamaine, and considered that the work simply reproduced his mathematical instruments without any serious understanding of the theory on which they depended. Subsequently Delamaine enjoyed royal favour and the appointment of tutor to the king in mathematics, and quartermaster-general. His widow described him in those terms, in 1645, when she petitioned the House of Lords. He left ten children, one of whom bore his name, who is tentatively identified with the mathematician Richard Delamaine the younger.

Charles I, just before his death, sent to his son James, Duke of York a silver ring-sundial made on the plan here described by Delamaine.

He wrote:

 This article incorporates text from a publication now in the public domain: "". Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900. 

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