page_title: John Farey Jr.
section_title: Instruments for drawing
hierarchical_section_title: John Farey Jr. / Work / Instruments for drawing
caption_attribution_description: English: Elliptograph in Encyclopædia Britannica, 1824
context_page_description: John Farey Jr. was an English mechanical engineering, consulting engineer and patent agent, known for his pioneering contributions in the field mechanical engineering.
  As consulting engineer Farey worked for many well-known inventors of the later Industrial Revolution, and was a witness to a number of parliamentary enquiries, inquests and court cases, and on occasion acted as an arbitrator. He was polymathic in his interests and contributed text and drawings to a number of periodicals and encyclopaedias.
  Farey is also remembered as the first English inventor of the ellipsograph, an instrument used by draughtsmen to inscribe ellipses.
context_section_description: The necessity of accomplishing drawings with accuracy in a limited time led Farey to invent in 1807 an instrument for making perspective drawings, for which he received a silver medal from the Society of Arts in 1814. In an accompanying letter printed in the Transactions, Farey explained in general:
  WITH this you will receive an instrument of my invention for drawing lines converging to a distant point. This I have found extremely useful in making perspective drawings, as it gives an artist the means of making a drawing upon a. board or table of moderate dimensions though the vanishing points fall at ever so great a distance; for the instrument is quite general in its proper ties, being capable of drawing parallel lines, which may therefore be considered as converging to a point at an infinite distance, or it may in a moment be altered to draw to a point within a few inches distance. I shall be obliged to you to communicate this to the Society.
  The first instrument of this kind, I made in the year 1807, and I have had it in constant use ever since, as it applies with advantage to almost every perspective drawing; l have been induced to present it to the Society, at the request of several members...
  An additional four page long explanation of Farey's "Instrument for drawing Lines to an inaccessible center" in Plate 2 (see image fig. 4, 5.) started explaining:
  This instrument acts upon the drawing board, or table, on which the paper is fastened, with as much facility and as little attention as a T square does, when drawing parallel lines, and will be found extremely useful to those who draw buildings, etc. in perspective, as the points to which the lines for such drawings should converge, will often fall at a distance of I2 and 15 feet from the picture, so as to render it impracticable to employ rulers of sufficient length to reach the points, and there is, except this instrument and Mr. Nicholson’s lately invented, no other practicable method of drawing such lines.
  The instrument consists of three rulers, A B and D, figs 4, which are united by a common centre-screw a, and have a thumb screw d, which fixes them fast at any angle at which they may be placed...etc, etc.
   
  In 1813 Farey also constructed a machine for drawing ellipses, the so-called ellipsograph. The device became so popular, that the 6th edition of the Encyclopædia Britannica (1824) included an article about it, which started with:
   
  ELLIPTOGRAPH, an instrument for drawing ellipses. The trammel is an instrument that has long been known and used for describing ellipses. On the principle of the trammel, Mr Farey constructed his elliptograph in a form much more commodious for drawing. Mr Farey's elliptograph is represented at fig. 5. Plate LXXIX. The circle A slides between the two parallel rulers D E. The circle 13 slides between two parallel rulers FG, at right angles to the former. In this way, if a line, joining the centres of the circles, is made to revolve, M, the extremity of that line, will describe an ellipse in the same manner, as the extremity E of the line C D E, fig. 1, does in the trammel. The elliptograph may be considered as a trammel, in which the pins C and D, rig. 1, are enlarged into the circles A and B, fig. 5...etc, etc.
  The drawing device was described in many other publications in his days, for example in Smith's The Mechanic; Or, Compendium of Practical Inventions, 1825 (see image), and it was described in the Edinburgh Encyclopædia (1832) along with four other devices by Farey. For this invention the gold medal of the same society was awarded hun.
caption: Elliptograph in Encyclopædia Britannica, 1824
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