Dictionary of National Biography, 1885-1900/Digges, Leonard (d.1571?)

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DIGGES, LEONARD (d. 1571?), mathematician, was the son of James Digges of Digges Court, in the parish of Barham, Kent, by Philippa, his second wife, daughter of John Engham of Chart in the same county. The family was an ancient and considerable one. Adomarus Digges was a judge under Edward II; Roger served in three parliaments of Edward III; James Digges was a justice of the peace many years, and sheriff in the second of Henry VIII. He left Digges Court to his eldest son John, and the manor of Brome to Leonard, who sold it, and purchased in 1547 the manor of Wotton, likewise in Kent, where he resided. We hear of an act passed in the fifth year of Elizabeth ‘for the restitution of Leonard Digges,’ but it is not printed among the statutes. He married Bridget, daughter of Thomas Wilford of Hartridge, Kent, and had by her Thomas [q. v.], a distinguished mathematician, and the editor of several of his works. The elder Digges died about 1571. He studied at University College, Oxford, but took no degree, though his ample means and leisure were devoted to scientific pursuits. He became an expert mathematician and land surveyor, and (according to Fuller) ‘was the best architect in that age, for all manner of buildings, for conveniency, pleasure, state, strength, being excellent at fortifications.’ Lest he should seem to have acquired knowledge selfishly, he printed in 1556, for the public benefit, ‘A Booke named Tectonicon, briefly showing the exact measuring, and speedie reckoning all manner of Land, Squares, Timber, Stone, etc. Further, declaring the perfect making and large use of the Carpenter's Ruler, containing a Quadrant geometricall; comprehending also the rare use of the Square.’ The next edition was in 1570, and numerous others followed down to 1692. The author advised artificers desirous to profit by this, or any of his works, to read them thrice, and ‘at the third reading, wittily to practise.’

A treatise, likewise on mensuration, left in manuscript, was completed and published by his son in 1571, with the title, ‘A Geometricall Practise, named Pantometria, divided into Three Bookes, Longimetria, Planimetria, and Stereometria, containing Rules manifolde for Mensuration of all Lines, Superficies, and Solides.’ The first book includes a very early description of the theodolite (chap. xxvii.), and the third book, on Stereometry, is especially commended for its ingenuity by Professor De Morgan. In the dedication to Sir Nicholas Bacon, Thomas Digges speaks of his father's untimely death, which was then apparently a recent event, and of the favour borne to him by the lord keeper. A second revised edition was issued in 1591. The twenty-first chapter of the first book includes a remarkable description of ‘the marvellous conclusions that may be performed by glasses concave and convex, of circular and parabolical forms.’ He practised, we are there informed, the ‘multiplication of beams’ both by refraction and reflection; knew that the paraboloidal shape ‘most perfectly doth unite beams, and most vehemently burneth of all other reflecting glasses,’ and had obtained with great success magnifying effects from a combination of lenses. ‘But of these conclusions,’ he added, ‘I mind not here more to intreat, having at large in a volume by itself opened the miraculous effects of perspective glasses.’ The work in question never was made public. Especially he designed to prosecute, after the example of Archimedes, the study of burning-glasses, and hoped to impart secrets ‘no less serving for the security and defence of our natural country, than surely to be marvelled at of strangers.’ The assertion that Digges anticipated the invention of the telescope is fully justified, as well by the above particulars as by the additional details given by his son in the ‘Preface to the Reader.’ He states elsewhere that his father's proficiency in optics was in part derived from an old written treatise by Friar Bacon, which, ‘by strange adventure, or rather destiny, came to his hands’ (Encycl. Metropolitana, iii. 399, art. ‘Optics’).

‘An Arithmeticall Militare Treatise, named Stratioticos: compendiously teaching the Science of Numbers … and so much of the Rules and Aequations Algebraicall, and Arte of Numbers Cossicall, as are requisite for the Profession of a Soldier,’ was begun by Leonard Digges, but augmented, digested, and published with a dedication to the Earl of Leicester, by Thomas in 1579 (2nd ed. 1590). Digges wrote besides: ‘A Prognostication Everlasting: Contayning Rules to judge the Weather by the Sunne, Moone, Starres, Comets, Rainbows, Thunder Clouds, with other extraordinary Tokens, not omitting the Aspects of the Planets’ (London, 1553, 1555, 1556, &c., corrected by Thomas Digges, 1576, &c.). This little manual of astrological meteorology gives the distances and dimensions of sun, moon, and planets, according to the notions of the time, and includes tables of lucky and unlucky days, of the fittest times for blood-letting, &c., and of the lunar dominion over the various parts of man's body. Digges's writings show an inventive mind, and considerable ingenuity in the application of arithmetical geometry.

[Biog. Brit. (Kippis); Wood's Athenæ Oxon. (Bliss), i. 414; Fuller's Worthies (1662), ‘Kent,’ p. 82; Hasted's Hist. of Kent, iii. 130, 756, 762; Harris's Hist. of Kent, p. 35, &c.; Philipott's Villare Cantianum, p. 60; Stow's Survey of London (1720), iii. 71; Pits, De Angliæ Scriptoribus (1619), i. 751; Bale's Scriptt. Brit. Cat. x. 110; Tanner's Bibl. Brit.; Watt's Bibl. Brit.; Poggendorff's Biog. Lit. Handwörterbuch; Companion to Brit. Almanac, 1837, p. 40, 1839, p. 57, 1840, p. 27 (A. De Morgan); Notes and Queries, 2nd ser. iv. 282, x. 162, 6th ser. x. 368, 515; Brit. Mus. Cat.]

A. M. C.