April 9

You see by the {i}nclosed, written to me by the Iesuite Pardie{s} Proffessr of ye mathematicks in the Colledge of Clermont at Paris how nimble yt sort of men is to animadvert vpon new theories He being a person of some repute there, I doubt not but you will expedite an answer for him \and yt/ in the same language, wherein he writeth.

Besides him, there is Monsieur Hugenius, yt hath also read and considered thesame {sic}, who giueth me this note vpon it in his letter of April 9. st. n; videl.

Pour ce qui est Sela nouvelle Theorie de Monsieur Newton touchant la lumiere et les couleurs, elle me paroit fort ingenieuse; mais il faudra voir, si elle est compatible auec toutes les experiences. Cependant i'ay estè bie{n} {illeg} de trouuer ce qu'il escrit touchant l'effet des verres e{t} miroirs en matiere de Lunettes, ou ie voy qu'il a re{m}{arquè} comme moy, le defaut dela refraction des verres convexes o{bj}{ec}tifs à cause de l'inclinaison de leur deux surfaces.

yr letter of march 30th was read before the R. Soc. on Thursday last, and they commanded me to thank you in their name for it, and for yr care of removing the inconveniences yt may lye agst yr reflecting Telescope. Some tryal will be made, I hope, wth a prismatical Chrystal, in stead of ye smal oval speculum And Mr Cock is at worke for one of 4 feet, \yet wth both ye speculums of med|t|al/; wch we long to see finisht, and yt we may try its performances.

The Transactions of March, wherein much is said of this Telescope of yrs, is now abroad, and I hope, your carrier will call this week \at my house/ for one of you. It would be well, if your answer to Mr Hooks objections could be ready, to be inserted in the Transactions of this present month, wch will goe to the presse about 10 \or 12/ days hence. If it cannot be ready time enough, I shall, if you permit me, put in the \yr/ two letters of march 26 and 30: they {illeg} {m}y {illeg} of good matter, {yt} {illeg} all {illeg} appear in publick, what hath been suggested by yrself concerning ye new T{o}{illeg}{t}s, {illeg} {illeg} {most} {illeg} {fai}thful se{rvan}t


To his honored friend
Mr Isaac Newton Professor
of the Mathematicks in Trinity
Colledge at


© 2020 The Newton Project

Professor Rob Iliffe
Director, AHRC Newton Papers Project

Scott Mandelbrote,
Fellow & Perne librarian, Peterhouse, Cambridge

Faculty of History, George Street, Oxford, OX1 2RL - newtonproject@history.ox.ac.uk

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