( Wtf) 
^heeycsof ft veral other Animals, and particularly of Cats> 
whofeeyesthis light appears Wewilbj wfcich {hews, that it pro- 
ccedech from their Chomides which hath much of this Coiourj 
but this Colour, norany other which may be in the chemidesy. 
brings no confufion to the Senfe of Seeing, for the Senfes re- 
eeive no impreffion from their own Organs. 
The reft of this firft Objedtion hath almuft no other foundati- 
on, but an interpretation you give to fome words of my writing 
c ifferent from my fenfe 5 for, when I faid, that dark and opaque 
bodies receive a great deal of impreffion from the light-, I did 
mean dark and opaque bodies both together^ for it had been fuf- 
ficient for me to name dark bodies, fince all dark bodies are o- 
paque; but my thought on this fubjed was, and ftill is^ thac 
tranfparent bodies^ as the Ayre, the Water, and the Retina in a 
living Animal, receive Imle impreflion from light, and that- 
Opaque bodies receive z great deal ^ but that dark bodies re- 
ceive more then all other Opaque bodies, and the Air and the 
Water a little lefs than the Retina. 
Nor do I believe, that darknefs is abfolutely nrcefTary for Vi- 
fion, but only for aftrongvifionj nor that the pidure of ob- 
jedis ought to be exprelTed on the Organ of Vifion 5 for, it fuf- 
liceth,thattherayes of each point of the Objefts be reunited in > 
adiftindandfeparated point, according as they anfwer one an- 
other 5 and you will ealily agree, that as a Convex glafs mak es ; 
the image of the Sun to appear on white paper with a great deal 
©f brightncfs andlightj and on black paper very obfcurely 5 al- 
though black paper (which fooii takes firej receives a great 
deal moreimpreffion than white: So the rayes of illuminated ob- 
jedts do'reuniteon a whitifli Choroeides^znd exprefs there a vifible 
pidure, and on a dark Choroeides^z very obfctire one, and vv' ich 
cannot befeen; but then the impreffion is alfo much ftronger 
in theblack than in the white: And this is the caufe, why Merr;>^ 
and Birds fee better and more diilindly then the greateft part of ' 
other Animals j for their choroeides being black, ^nd by confe»- 
quence very feniibls of lighr^ they contrad much their pnn;i- 
la or fight-hole of the Eye^ which makes the Raye?, thati 
gafs there/rom each ^oii^tof the Objedj to be all very near the 
