C 5oS4 ) 
ifaac Newtons Anfwer to fime Confderationi upon bis Do, 
Bme pf Light and Golors ; wbicb DoUrine was printed in 
Nnmb.Bo.ofthefetraSs. 
1 J^, I have already told you^ that at the perufal of the con- 
^fideratioDSj you feiat me, on my Letter conceroiog Refrac 
tions and Colors^ I fouod nothing, thai, as 1 conceived^tBi'ghc 
not without dilScolty be anfwer'd. And though I find the 
Confiderer fomewhat more concern'd for an Hypothefis^ than I 
expeded yet I doubt not, but we have one common defign ^ 
I mean, a lincere endeavour after knowledge^ without valuing 
uncertain fpeculatious for their fubtleties, or defpifing cer- 
tainties for their plainnefs : And on confidence of this it is, 
that I make this return to his difcourre."^ 
' The/r/?thin2 that offers it felf 
n^diep to he here printed at length, IS lelb agreeable to niej and I begio 
kecaufe in the body of this j^nfwer With it beCaufe It IS fo. The CCnii- 
are to h met vjith the chief particff Ac^^^^f t-^ L j 
i.rf, Mn the AriimL was ^^^f plealed to reprehend me 
£OHftrn*d. tor laying afide the thoughts of im- 
f « a- r ^ provino; Optiques by RefraBiom 
I. Ofths FraBfqut part of Op* \^ . . ^ , V t-^ i v ^ (^uwfis, 
tiiueu If he had obliged me by a private 
Letter on this o^calion^ 1 would 
have acquainted him Vith my fucceffes on the Tryals I have 
made of that kind^ which I (hall now fay have been lefs than 
I fometimes expeitedj and perhaps than he at prefent hopes 
for. But fince he is pleafed to take it for granted, that I have 
let this fubjeapafs without due examination, I fliallreferhim 
^ Printed in Numb. 8o. of thefi ^^Y f^^^^r Letter, * by which 
rra^s. that conjecrure wiH appear to be 
un-grounded/ For, what I faid 
there, was inrefpeft of Telefcopes of the ordinary conftrudi' 
on, hgnifying,that their improvement is not to be expected 
from the well.figurwg o£ Glaffes, as Opticians have imagin'd 5 
but 1 defpaired not of their improvement by other conftru- 
a:ions 3 which made me cautious to infert nothing that might 
intimate the contrary* For, although fucceffive refradioDS 
that are all made the fame way, do neceffarily more and more 
augment the errors of the firft refradfon 5 yet ft feem'd not 
impoffible f or r(?«/rjry refraaions fo to correa each others 
inequalities, as to make their diiFereuce regular 5 and^ if that 
could 
