PRINCIPIA. OPTICS 35 



errors of the press, the longitude may be found by land and sea, 

 either night or day, when the moon is visible, and in proper 

 weather, within very few miles of certainty. 1728. 4to. [172 



Young, Robert. Examination of the third and fourth definitions of 

 the first book of the Principia, and of the three Axioms or Laws 

 of Motion. 1787. 4to. [173 



III. OPTICS 



Opticks: | or, a | Treatise | of the | Reflexions, Refractions, | In- 

 flexions, and Colours | of | Light. | Also | Two Treatises | of the | 

 Species and Magnitude | of | Curvilinear Figures. | 

 London, | Printed for Sam. Smith, and Benj. Walford, | Printers to 

 the Royal Society, at the Prince's Arms in | St. Paul's Church- 

 yard. MDCCIV. | 4to. [174 



Collation : Title and Advertisement, 2 11. + Book I. of Optics, pp. [i] [144] 

 + Books II. and III., pp. [i] [137] + i blank : + Title : Enumeratio 

 Linearum Tertii Ordinis [138] + i blank -f [139] [162] : Tractatus 

 de Quadratura Curvarum, [163] [211] -\- i If. of Errata. Sigs. Title 

 and Advertisement, 2 11, and A S, Aa, Bb, Dd Ss 4 -f- i If. inserted 

 between Tt i and 2 -f Tt Ddd 4 , Eee 2 , 19 Plates: Book I. part i, 

 plates i v after p. 80 j Book I. part 2, plates i iv after p. 144; 

 Book II. plates i, n after p. 48 ; Book III. plate i after p. 137 ; Enu- 

 meratio, plates i vi after p. 162 ; Tractatus, plate i after p. 211. 



Title-page printed in red and black. It will be noticed that Newton did not attach his 

 name to the work, only the initials * I. N.' at the end of the Advertisement. 



The Two Treatises added to this edition are : 



1. Enumeratio Linearum Tertii Ordinis. 



2. Tractatus de Quadratura Curvarum. 



Newton says in the Advertisement : ' Part of the ensuing Discourse about Light was 

 written at the desire of some gentlemen of the Royal Society, in the year 1675 an d read 

 at their meetings, and the rest was added about Twelve Years after to complete the Theory ; 

 except the Third Book and the last Proposition of the Second, which were since put together 

 out of scattered Papers. To avoid being engaged in Disputes about these Matters, I have 



