( 5087 ) 
fome meafure capable of being explicated not only by thits 
bat by many other Mechanical Hypotbefes^ And therefore I 
chofe to decline them ali^ and to fpeak of Light in general 
terms, confidering itabftradly^ as fomething or other propa« 
gated evvry way in ftreight lines from luminous bodie^j with- 
out determining, what that Thing is» whether a confufed 
Mixture of difform qualities, or Modes of bodies^ or of Bos, 
biesthemielveSj or of any Virtues^ Powers, or Beings what^ 
foever* And for the fame reafon I chofe to fpeak of Colours 
according to the information of our Senfes^ as if they were 
QuaUties of Light without, u%. Whereas by ths^t Hypuhefs I 
muft have cpnfidered them rather as Modes of Senfation^ exi 
cited in the mind by various motions, figures, or fizes of the 
corpufcles of Light, making various Mechanical impreflions 
on the Organ of Sen(e 5 as I expreiled icin thac place, where I 
fpake of the Cprporeity.of Light. 
Boifuppofing I had propoifnded thzt Hypothecs, L uoder- 
fland not, why thy Objedtor lliould fo much endeavour to op- 
pofe ir* For certainly it has a much greater affinity with his 
own Hypothjis^ . than he feems to be aware of ^ the Vibrations 
of the ^ther being as ufeful and nec^ffary in this^ as in hisJPoti 
aflTuming the Rays of Light to he fmall bodies^ emitted every 
way from Shining fubftanceSj thofe, when chcy in^pinge on 
any Refra6ting or PvefledSing fuperficieSj muft as nec^fl^rily 
excite Vibrations in the cether^ as Stones do in water when 
thrown into \u And fuppofing thefe Vibrations to be of fe= 
veral depths or thicknelTeSg accordingly as they arq excited by 
the liiid corpulcular rays of various fizes and veIociriesu>f what 
ufe they will be for explicating the manner of Refledion and 
Refraction, the production ofHeat by the Sun^beams, theE^ 
miffion of Light frpm burning putrifying, or other fubftaRCe^j 
whofe parts are vehemently, agitated^ the Ph'/senometm of tbio 
t4:aQfparent Plates and BubleSs and of all Natural bodieSj the 
Manner of VifioUj, and die Difference of Colorsg as alio theif 
Harmony asd Difcord^ i fhall leave to their confideration , 
viho may think it worth their endeavor to apply this fffpothcfir 
to ih^ folu^lonQ^ ph^mmetm^. 
