tree instruments making perspective drawings, 1814. farey s invention pictured in middle in fig. 4 , 5.
the necessity of accomplishing drawings accuracy in limited time led farey invent in 1807 instrument making perspective drawings, received silver medal society of arts in 1814. in accompanying letter printed in transactions, farey explained in general:
with receive instrument of invention drawing lines converging distant point. have found extremely useful in making perspective drawings, gives artist means of making drawing upon a. board or table of moderate dimensions though vanishing points fall @ ever great distance; instrument quite general in proper ties, being capable of drawing parallel lines, may therefore considered converging point @ infinite distance, or may in moment altered draw point within few inches distance. shall obliged communicate society.
the first instrument of kind, made in year 1807, , have had in constant use ever since, applies advantage every perspective drawing; l have been induced present society, @ request of several members...
an additional 4 page long explanation of farey s instrument drawing lines inaccessible center in plate 2 (see image fig. 4, 5.) started explaining:
this instrument acts upon drawing board, or table, on paper fastened, facility , little attention t square does, when drawing parallel lines, , found extremely useful draw buildings, etc. in perspective, points lines such drawings should converge, fall @ distance of i2 , 15 feet picture, render impracticable employ rulers of sufficient length reach points, , there is, except instrument , mr. nicholson’s lately invented, no other practicable method of drawing such lines.
the instrument consists of 3 rulers, b , d, figs 4, united common centre-screw a, , have thumb screw d, fixes them fast @ angle @ may placed...etc, etc.
farey s elliptograph, 1825
in 1813 farey constructed machine drawing ellipses, so-called ellipsograph. device became popular, 6th edition of encyclopædia britannica (1824) included article it, started with:
elliptograph in encyclopædia britannica, 1824
elliptograph, instrument drawing ellipses. trammel instrument has long been known , used describing ellipses. on principle of trammel, mr farey constructed elliptograph in form more commodious drawing. mr farey s elliptograph represented @ fig. 5. plate lxxix. circle slides between 2 parallel rulers d e. circle 13 slides between 2 parallel rulers fg, @ right angles former. in way, if line, joining centres of circles, made revolve, m, extremity of line, describe ellipse in same manner, extremity e of line c d e, fig. 1, in trammel. elliptograph may considered trammel, in pins c , d, rig. 1, enlarged circles , b, fig. 5...etc, etc.
the drawing device described in many other publications in days, example in smith s mechanic; or, compendium of practical inventions, 1825 (see image), , described in edinburgh encyclopædia (1832) along 4 other devices farey. invention gold medal of same society awarded hun.
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