J.M.W. Turner: Sketchbooks, Drawings and Watercolours

ISBN 978-1-84976-386-8

Joseph Mallord William Turner Lecture Diagram: Two Equilateral Triangles c.1817-28

Joseph Mallord William Turner 1775–1851
Lecture Diagram: Two Equilateral Triangles circa 1817–28
Turner Bequest CXCV 26a
Pencil and watercolour on white wove paper, 492 x 687 mm
Watermarked ‘J WHATMAN | TURKEY MILLS | 1817’
Inscribed by Turner in red watercolour ‘1’ top left and ‘2’ top right
Inscribed by John Ruskin in red ink ‘26a’ bottom right
Accepted by the nation as part of the Turner Bequest 1856
Made in connection with Turner’s lectures as Professor of Perspective at the Royal Academy, this diagram of two equilateral triangles is related to sketches in his notes, which suggests that he used it, along with another diagram of triangles numbered ‘3’, ‘4’, and ‘5’(Tate D16998), in later lectures on geometry.1
Turner, ‘Royal Academy Lectures’, circa 1807–38, Department of Western Manuscripts, British Library, London, ADD MS 46151 W folios 2, 4.
Technical notes:
Peter Bower (unpublished notes)1 writes that the sheet is Super Royal size Whatman paper made by Finch and Thomas Robert Hollingworth, at Turkey Mill, Maidstone, Kent.
Notes in Tate catalogue files.
Blank, save for an inscription by an unknown hand in pencil ‘6’ bottom left

Andrea Fredericksen
January 2004

Supported by The Samuel H. Kress Foundation

Revised by David Blayney Brown
January 2012

How to cite

Andrea Fredericksen, ‘Lecture Diagram: Two Equilateral Triangles c.1817–28 by Joseph Mallord William Turner’, catalogue entry, January 2004, revised by David Blayney Brown, January 2012, in David Blayney Brown (ed.), J.M.W. Turner: Sketchbooks, Drawings and Watercolours, Tate Research Publication, December 2012, https://www.tate.org.uk/art/research-publications/jmw-turner/joseph-mallord-william-turner-lecture-diagram-two-equilateral-triangles-r1136778, accessed 27 September 2021.