The practical draughtsman's book of industrial design, and machinist's and engineer's drawing companion: forming a complete course of mechanical, engineering, and architectural drawing (1854)
Armengaud, aîné (Jacques-Eugène), 1810-1891, Armengaud, Charles A., 1813-1893, Amouroux, Jules, Cory, William Johnson, 1823-1892 · New York, Stringer & Townsend · leaf 313
ctions. One of the most economically useful instruments of thedraughtsman is the Pentagraph; but it is one which requiressuch extreme accuracy and truthfulness in its construction, thatits consequent cost puts it out of the reach ef the majority ofthose who need it. By means of it, drawings may be… … r>- ■, ■!*£■ pencil by the angular movements of a series of levers oscillatingupon a fixed centre. If one arm of a lever is twice as long as theother, the arc described by its extremity will be twice as great,whatever be the extent of the movement. In this case, however,the radii of the arcs…
Decorative arts · Drawing
Internet Archive · Clark Art Institute Library · Public Domain Mark 1.0. Free to use for anything.
