FIRST EDITION, 8vo (162 x 100mm.), woodcut vignette on title, full-page coat-of-arms, illustrations and diagrams, 2 folding plates, contemporary vellum (with modern printed label on spine, slightly spotted, a few side-notes just shaved, lacking ties

"ad usus Gasparii servantii", old inscription on title; sale in these rooms 23 April 1987, lot 186, Quaritch; bought from Bernard Quaritch, London, 1990; Erwin Tomash, booklabel

Tomash & Williams G37; Houzeau & Lancaster 3276 (mentions an edition of 1550, but the instrument was not invented by Gemma Frisius until 1555); USTC 403235

the condition of this lot is as described in the catalogue description
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

This work was unfinished at Gemma Frisius' death in 1555 and was completed by his son Cornelius and published in the following year. Gemma had founded a workshop which produced globes and mathematical instruments and was noted for his skills as an instrument-maker by Tycho Brahe, among others. Here he describes the construction and use of an astrolabe of his own devising and includes sections on eclipses and their observation, sundials and horoscopes.