BT WHICH THEOK, OR OTHERS, HAVE LONG AGO VITIATED THESE BOOKS, ARE COR-
RECTED, AND SOME OP EUCLID'S DEMONSTRATIONS ARE RESTORED.

BY ROBERT SIMSON, M. D.

Emeritus Professor of Mathematics in the University of Glasgow.

TO THIS EDITION ARE ALSO ANNEXED,

ELEMENTS OFPLJUtEAXO SPHERICAL TRIGONOMETRY.
PHILADELPHIA:

PUBLISHED BY

ROBERT DESILVER, No. 110, WALNUT STREET,

AND

THOMAS DESILVER, No. 253, MARKET STREET.

J. Maxwell, Printer.

1821.