Two New Instruments for Drawing in Perspective

ART. ARCHITECTURE. PERSPECTIVE. Gargiolli, Guglielmo (d. 1664)

Iride celeste de Guglielmo Gargiolli […] Strumento con il quale con facilita si puo disegnare qualsivoglia veduta, e sapere la sua giusta altezza, larghezza, e lontanaza dal luog'ove si sta a disegnarla.

Florence: Giovanni Antonio Bonardi, 1655


Quarto: 20.3 x 14.7 cm. 93 pp. A-M4 (H1 is a cancel, -L4), π1. With an added portrait-frontispiece of the author, 1 folding table, and 5 folding plates.


A fine copy in contemporary vellum, slightly loose, with minor faults: two small holes in the portrait, touching the image only very slightly. The third plate with two similar holes, not affecting the image. Second plate lightly toned. Small natural paper flaw in M2. As in all copies, the illustrations on pages 74-75 were corrected in the printing shop by attaching new separately printed diagrams. H1 is a cancel. L4 excised (as in all copies examined; pagination is continuous.) The engraved portrait-frontispiece of the author, while not signed, is attributed to Stefano della Bella (See De Vesme, p. 95). Rare: 4 copies in North America: Columbia, Harvard, Wisconsin, Morgan.

Very rare first edition of this treatise on perspective by Guglielmo Gargiolli, the renowned mathematician of the Medici courts of Siena and Florence, and a correspondent of Galileo. The work is dedicated to Ferdinand II, Grand Duke of Tuscany. The illustration includes many woodcut diagrams in the text and 5 folding plates showing the instruments and their applications in landscapes, urban settings, rendering letterforms.

Gargiolli gives the description of two instrument of his own invention, the Iride Celeste (“Celestial Iris”) and the Croce Travaliata which enable one to draw proportionally accurate perspective views, as well as to estimate, from a distance, the dimensions of an object and its distance from the observer. 

The work begins with essential lessons in geometry (how to calculate the dimensions and volumes of complex geometric solids, for instance.) In the second book, Gargiolli explains how to use his instruments to determine the height, depth, width and distance of an object without having to reposition the instrument or having to use multiple instruments. One special feature of the Iride described by Gargiolli is that it allows the observer to reduce or enlarge his image when drawing (a mathematical analogue to Scheiner’s mechanical pantograph.)

It is in the third and longest book, “Scenografia, o Prospettiva”, that Gargiolli demonstrates the application of the matter learned in the previous two books to making art. He begins with a discussion of certain precepts regarding the nature of vision, the interpretive action of the mind in making sense of what it sees, and the intellectual understanding of how geometry governs perspective. Gargiolli then gives lessons on how to draw using everything that has been learned up to this point. The examples become increasingly more complex as the book progresses, allowing the student to cope with more complex compositions. The book ends with instructions on how to render a shadow cast from a suspended body.

The plates:

The first plate, really a paper instrument, is a precise rendering of the Iride Celeste. At the upper corners of the engraving are two scenes of people using the instrument. The second shows the other instrument, the Croce Travaliata, and a city street with measurements applied to it. The third plate shows the Croce being used for other feats of mensuration (establishing the height of a tower, etc.). The fourth shows two more complicated city views; the fifth plate shows perspective projections of a solid letter “I” seen from various angles.

Riccardi, VII, p. 40, «è de noverarsi fra i primi tentativi di distanziometria», Riccardi mistakenly records an earlier edition of 1619 relying on Targioni, Atti, I, p. 334, but the date is obviously incorrect in respect of Gargiolli’s rather obscure biography. See ‘Le opere dei discepoli di G. Galilei, Carteggio (1642–48)’, vol. I, a cura di P. Galluzzi e M. Torrini, Firenze 1975, no. 11