they have always agreed with the Sun. As to the Printing of 
the Figure of my New Watch , I (hall defer that yet a while : but 
it (hall in time appear with all the Demonflrations thereof togc- 
ther with a Ireatife of Pendulums, written by me fome days fince 3 
which is of a very fubtile Speculation. 
fbe Char after, lately pblifbed beyond tbeSeas,of an Eminent 
Perfon, not long fince dead at Tholoufe , vcbere be was a 
Councellor of Parliament. 
It is the defervedly famous Monjieur de Fermat 0 who was 3 
( faith the Author of the Letter) one of the moft Excellent 
Men of this Age, a Genius fo univerfal, and of favaft an ex- 
tent ? that if very knowing and learned Men had not given 
teftimony of his extraordinary merit, what with truth can be 
faid of him, would hardly be believed. He entertained a con- 
ftant correfpondence with many of the molt illuftrious Mathe- 
maticians of Europe , and did excel in all the parts of Mathema- 
tical Science i a Xeftimony whereof he hath left behind him in 
the following Books. 
A Method for the Quadrature of P ar ahold s of all degrees. 
A Book De Maxi mis & Minimis , which ferveth not only for 
the determination of Problems of Plains and Solids 5 but alfo 
for the invention of ‘Tangents and Curve Lines 3 and ot the Centres 
of Gravity in Solids 5 and likewife for Numerical Quelfions. _ 
An Introdudion to the Dottrine of Plains and Solids^ which 
is an Analytical Treatile , concerning thefolution of Plains and 
Solids , which had been leen (as the Advertiler affirms J before 
MonfieurDe-r Carteshad publifh’d anything upon thisSubjeft. 
ATreatife De Contattibus Spbevricis , where he hath demon- 
ftrated in Solids, what Mr. Viet , Mailer of Rcquefts, had but 
demonflrated in Plains. 
Another Treatife, wherein he eftablifheth and demonftrateth 
the two Books of Apollonius Pergeeus, of Plains. 
And a General Method for the dimenlion of Curve Lines } &c . 
Befides , having a perfeft knowledge in Antiquity, he was con- 
fulted from all parts upon the difficulties that did emerge there- 
in ; he hath explained abundance of ob (cure places ^ that are 
found 
