As a **geometer** he is classed by Eudemus, the greatest ancient authority, among those who "have enriched the science with original theorems, and given it a really sound arrangement."

He wrote to the great **geometer** a letter on the principles of mechanics, which evoked an immediate and enthusiastic response.

LORENZO MASCHERONI (1750-1800), Italian **geometer**, was professor of mathematics at the university of Pavia, and published a variety of mathematical works, the best known of which is his Geometria del compasso (Pavia, 1797), a collection of geometrical constructions in which the use of the circle alone is postulated.

HERO OF ALEXANDRIA, Greek **geometer** and writer on mechanical and physical subjects, probably flourished in the second half of the 1st century.

Dinostratus, a Greek **geometer** and disciple of Plato, discussed the curve, and showed how it effected a mechanical solution of squaring the circle.

The lectures attracted hearers so eminent as Humboldt the cosmologist, Poinsot the **geometer** and Blainville the physiologist.

APOLLONIUS OF PERGA [PERGAEUS], Greek **geometer** of the Alexandrian school, was probably born some twenty-five years later than Archimedes, i.e.

His treatise on Conics gained him the title of The Great **Geometer**, and is that by which his fame has been transmitted to modern times.

PAPPUS OF ALEXANDRIA, Greek **geometer**, flourished about the end of the 3rd century A.D.

Secondly, his theory of inference contains the admission that we infer beyond sensations: he remarks that the space of the **geometer** is beyond space-sensations, and the time of the physicist does not coincide with time-sensations, because it uses measurements such as the rotation of the earth and the vibrations of the pendulum.

Die **Geometer** vor Euklides (Leipzig, 1870); H.

Claude Mydorge (1585-1647), a French **geometer** and friend of Descartes, published a work De sectionibus conicis in which he greatly simplified the cumbrous proofs of Apollonius, whose method of treatment he followed.

He further became member of the Institute in 1812, examiner at the military school at St Cyr in 1815, leaving examiner at the Ecole Polytechnique in 1816, councillor of the university in 1820, and **geometer** to the Bureau des Longitudes in succession to P. S.

De Maupertuis as associate **geometer** of the Academie des Sciences.