A TREATISE

ON THE

PRINCIPAL

MATHEMATICAL INSTRUMENTS

EMPLOYED IN

SURVEYING, LEVELLING, & ASTRONOMY,

&c. &c.

FREDERICK W. SIMMS,

SURVEYOR & CIVIL ENGINEER,

LATE OF THE ROYAL OBSERVATORY, GREENWICH, AND FORMERLY
EMPLOYED ON THE ORDNANCE SURVEY.

London:

SOLD, FOR THE AUTHOR,

BY MESSRS. TROUGHTON AND SIMMS, 136, FLEET STREET;

J. WEALE, ARCHITECTURAL LIBRARY, 59, HIGH HOLBORN;

AND

J. SOUTER, 73, ST. PAUL'S CHURCH-YARD.