( $o86 ) 
tiques ; yet I muft for this as well as other confideratio ds pre 
fcr them in the Theory before Refractions, 
Whether the Parabola be more difBcuk to dcfcribe than the 
Hyperbola or EllipJis^m^Y hQz ^<ere : But I fee noabfolate 
neceflity of endeavouring after any of their defcriptions. For, 
if Metals can be ground truly Spherical, they will bear as great 
Apertures^ as 1 believe men will be well able to communicate 
an polifli to. And for Dioptrique Telefcopes, I tohl 
youj that the difficulcy confifted not io the Figure of the glafs, 
butin theDifformity of Refradions : Which if it did nor, I 
eould tell you a better and more eafie remedy than the ufe 
of the Conic SeSions. 
Thus much concerning the Vra^tiaue 
fJt. ^ ^''^**'^ P^^^ ®^ Optiqucs. 1 fliall now take a view 
cf theConfiderationsonmyTSw/V/. And 
thofe confift fn afcribing an Hypothefs to me,which is not mine* 
in AfTerting ^ri /7j/'fl//'£/Sf>, which, as to the principal parts, is 
not againft me 5 in Granting the greateft part of my difcourfe 
ifexplicatedby thatHy/o/ify{>5 and in Denying fome things, 
the trath of which would have appear d by an experimental 
examination* 
Of thefe Particulars I ftiall difcourfe ia 
l&^C!'''""" order. Aud firft of ihe H^^«.^#. which 
is afcribed to me in thefe words : But grant 
his frfi fuppofttion^ that light is a bedy^ and that as many colours or 
degrees ai there may be^fomany bodies there may be s all which com* 
ponndedtogether would make white ^ &c. This, it feemSj is taken 
fcr my Hypothecs. Ti$ true^ that from my Theory I argue the 
£;<9r/;(?m>)' ofLights but I do it without any abfolute pofitive- 
iiefs, as the word perhaps intimates^-and make it at m.oft but a 
very plaufible confequeme of the DocJlrine, and not a funda- 
mental Suppofitiony nor fo much as any part of it • which was 
wholly comprehended in the precedent Propoficions» And I 
fomewhat wonder, how the Ohjutor could imagine, thatjwhea 
1 had afTerted the Theory with the greateft rigour, I (hould 
be fo forgetful as afterwards to affert the fundamental fuppo^ 
fition itfelfwith no more than a />f r£^^/. Had I intended any 
fuch Hypotbejis^ 1 fhould fomewhere have explained it. But I 
knew^ that the Properties^ which I declared of Lights ^vere in 
fome 
