MEMBER OF THE INSTITUTE, AND OF THE LEGION OF HONOUR, AND

OF THE ROYAL SOCIETIES OF LONDON AND EDINBURGH, &c,

EDITED BY

- DAVID BREWSTER, LL. D.
FELLOW OF THE ROYAL SOCIETY OF LONDON, AND SECRETARY

TO THE ROYAL SOCIETY OF EDINBURGH, &c. &c.

WITH NOTES AND ADDITIONS, AND AN INTRODUCTORY

CHAPTER ON PROPORTION.

است اما ۱۰ نما:تر

EDINBURGH,

PUBLISHED BY

OLIVER & BOYD, HIGH STREET;

AND

G. & W. B. WHITTAKER, AVE-MARIA-LANE, LONDON.

1822.

ОКЕ

WILLIAM WALLACE, Esq. F. R. S. E. &c.

AND

Professor of Mathematics

IN THE

UNIVERSITY OF EDINBURGH,

THIS TRANSLATION OF

LEGENDRE'S ELEMENTS OF GEOMETRY

IS INSCRIBED,

IN TESTIMONY OF THE RESPECT AND ESTEEM

OF

THE EDITOR.

PREFACE OF THE EDITOR.

THE “ Elements of Geometry and Trigonometry,” by M. Le Chevalier Legendre, are so well known, and have been so highly esteemed in every part of Europe, that no apology can be required for presenting a translation of them to the English reader. The original work has undergone no fewer than eleven large impressions, and its distinguished author is at present occupied in preparing the twelfth edition for the press.

Upon announcing to M. Legendre my intention of superintending an English translation of his Elements of Geometry, and requesting his sanction and assistance, he kindly transmitted to me the following materials, with which the present edition has been enriched.

I. A new demonstration of the solidity of the pyramid, discovered by M. Queret of St Malo, which is substituted in place of the former demonstration, and forms Prop. XVII. and XVIII. of Book VI.*

M. Queret has been anticipated in this demonstration by the late Professor Playfair.