:

Ч

A

COMPLEAT SYSTEM

O F

OPTICKS

In Four BOOKS, viz.

A Popular, a Mathematical, a Mechanical, and
a Philofophical Treatife.

To which are added

REMARKS upon the Whole.

BY

ROBERT SMITH LL.D.

Profeffor of Aftronomy and Experimental Philofophy at CAMBRIDGE,
and Master of Mechanicks to his MAJESTY.

Quid tam mirabile, quam particulam corporis quandam ita fabricatam esse, ut ejus opera animal
fentiat procul pofitorum corporum figuram, pofitum, motum quemlibet, diftantiam; idque etiam
cum colorum varietate, quo diftinctius ea dignofceret? Nihil eft, in quo manifeftius Geometria
artem Deus exercuerit. Hugenii Cofimotheoros. p. 40.

CAMBRIDGE,

Printed for the AUTHOR, and fold there by Cornelius Crownfield, and at London
by Stephen Auften at the Angel and Bible in St. Paul's Church-yard, and
Robert Dodfley at Tully's Head in Pall-Mall. MDCCXXXVIII,

то

THE RIGHT HONOURABLE

EDWARD WALPOLE Efq;

Principal Secretary to his GRACE the DUKE of DEVONSHIRE as Lord-Lieutenant of IRELAND, and one of His MAJESTY'S most Honourable Privy-Council for that Kingdom.

SIR,

OF

F all the incidents in my life there is none I reflect upon with greater pleasure, than the happiness of falling into your acquaintance at CAMBRIDGE. There, among the many agreeable hours I had the honour of paffing in your company, you may remember the converfation fometimes turned upon Opticks, a Science you knew I had taken fome pains in: And the curiofity you then discovered, in relation to some