!

TOGETHER WITH THE

ELEVENTH AND TWELFTH.

The Errors, by which THEON, or others, have long ago Vitiated
these Books, are Corrected,

And fome of EUCLID'S Demonstrations are Restored.

ROBERT SIMSON, M. D.

Emeritus Profeffor of Mathematics in the University

QA 451

56

1762

SION COLLEGE LIBRARY.

SOLD BY ORDER OF THE

PRESIDENT AND GOVERNORS 1938.

TO THE

KING

THIS EDITΙΟΝ

OF THE

PRINCIPAL BOOKS

OF THE

ELEMENTS OF EUCLID

AND OF THE

BOOK OF HIS DATA

IS MOST HUMBLY DEDICATED

BY

HIS MAJESTY'S

MOST DUTIFUL, AND

MOST DEVOTED

SUBJECT AND SERVANT,

ROBERT SIMSON.