geometric pen or ellipsograph
Date: circa 1813
Inventory Number: DW0470
Classification: Ellipsograph
Subject:
Maker: W. & S. Jones (fl. 1791 - 1859)
Inventor: Count Giambattista Suardi (1711 - 1767)
Cultural Region:
Place of Origin:
Dimensions:
ellipsograph: 21 × 25 × 25 cm (8 1/4 × 9 13/16 × 9 13/16 in.)
case: 7 × 20 × 24 cm (2 3/4 × 7 7/8 × 9 7/16 in.)
Accessories: crank; gears (14); pencil arm; thumbtacks (5); stub pencils (5); pencil holder; flat mahogany case
Description:
The frame of this drawing instrument is made of three curved legs, contrived to fold within one another for convenience of packaging. Under the center point is a vertical axis supporting a fixed pinion and shaft handle. To the lower part of the axis, any of the gear wheels can be adapted.
From the lower part of the central axis an arm is fixed and contrived to turn around the main axis. On that arm are two sliding attachments, on which any gear wheel can be attached. At the end of that arm, another one is fixed that carries the pencil. It can slide backwards and forwards to vary the distance of the pencil to its supporting attachment.
The great number of wheels produce hundreds (even thousands) of different geometrical curves. The number of teeth on each wheel is engraved on them. Everything is stored is a small mahogany box.
To understand how this instrument works, take a look at the attached video.
From the lower part of the central axis an arm is fixed and contrived to turn around the main axis. On that arm are two sliding attachments, on which any gear wheel can be attached. At the end of that arm, another one is fixed that carries the pencil. It can slide backwards and forwards to vary the distance of the pencil to its supporting attachment.
The great number of wheels produce hundreds (even thousands) of different geometrical curves. The number of teeth on each wheel is engraved on them. Everything is stored is a small mahogany box.
To understand how this instrument works, take a look at the attached video.
Signedin box, trade label: W, & S, JONES, / Opticians, &c / No. 30 Lower Holborn, / London.
on the pencil arm, italics: W & S. Jones 30 Holborn, London.
on the pencil arm, italics: W & S. Jones 30 Holborn, London.
Primary SourcesGiovan Battista Suardi, Nuovi istromenti per la descrizione di diverse curve antiche e moderne e di molte altre, che servir possono alla speculazione de’ Geometrici, ed all’uso de’ Practici (Brescia, 1752).
George Adams, Geometrical & Graphical Essays, Containing a General Description of the Mathematical Instruments used in Geometry, Civil and Military Surveying, Levelling, and Perspective; with new Practical Problems, illustrated by Thirty-Four Copper Plates. By the Late George Adams, Mathematical Instrument Maker to her Majesty, Corrected and enlarged by W. & S. Jones, 4th ed. (London, 1813).
[For the online version of this book, referring especially to the ellipsograph, see Google books.]
George Adams, Geometrical & Graphical Essays, Containing a General Description of the Mathematical Instruments used in Geometry, Civil and Military Surveying, Levelling, and Perspective; with new Practical Problems, illustrated by Thirty-Four Copper Plates. By the Late George Adams, Mathematical Instrument Maker to her Majesty, Corrected and enlarged by W. & S. Jones, 4th ed. (London, 1813).
[For the online version of this book, referring especially to the ellipsograph, see Google books.]