( 5o87 ) 
fome meafure capable of being explieated not only by that^ 
bat by many other Mechanical Hypothefes^ And therefore I 
chofe to deGlinc them all^ and to fpeak of Ligl4 in gemral 
terms, confidering itabftradHy, as fomething or other propa. 
gated every way in ftreight lines from luminous bodieSj with, 
out determining, what that Thing is; whether a confufed 
Mixture of difForm qualities, or Modes of bodies^ orofBo^; 
biesthemlclvesj or of any Virtues^ Powers, or Beings what- 
foever* And for the lame reafon 1 chofe to fpeak of Colours 
accordingto the information of our Seufes, as if they were 
Qualities of Ligjit 2p/Vio/^^ us. Whereas by that Hypetbejis I 
muft have confidered them rather as Modes oi SenfatioOj e:^*. 
cited in the mind by various motions, figures, or fizes of the 
CQrpufcles of L'ght, making various Mechanical imprefBons 
on ttie Organ ofSenfe^ as 1 expreffed it in that place, where I 
ipake of the Corporeity of Light. 
Butfuppofibg I' had propopnded ihzt Hy path fis, r uader* 
ftand not, why the Objecftpr fllould fo much endeavour to op^ 
pole it* For certainly it has . g much greater affinity with his 
own tfypothefis^ than he leemskt be aware of ; the Vibrations 
of the JEther being as ufeful andne^^efTary in this^ as in ^i/.For^ 
afluEning the Rays of Light to be fmall bodies, emitted every 
way from Shining lubftances^ thofc, when they impinge 00 
any Refra£ting orflefle<Sting fuperficieSj.muft as neccflarily 
excite Vibrations in the (Bther^ as Stones do in water when 
thrown into iu And fuppoling tbefe Vibrations to be of le^ 
veral depths or thicl^aeffes^ accordingly as they are ex-c^ted by 
the laid corpulcular rays of various fizes and velocities^of what 
ufe they will be for explicating the manner of Rtflecftioo and 
Refraction, the productionof Heat by the Sun^beams, theE ^ 
miffipn of Light from burning putrifyingj or other fubftances^ 
whofe parts are vehemently, agitated^ the- Vlmmmena of thin 
traolparent Plates and Bubles. and-of all Namral bodiesj the 
Manner pfVifioUj and the DifFerenQc of Colors^, as alio their 
Harmony and Difcord ; i lhall leave to their confid^ration ^ 
who may think it worth their endeavpr to apply this HypHhiftf 
to the foiution of phsjionum^ 
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