t 695 ) 
For further aflbrance in this Experiment ^ left prepofleli. 
on, occafioncd from previous knowledge of the Silks fcicua- 
tioninaftreight line, might poffibly prejudice the judgment 
of tbeeyeCasfomeiimes I have obferved to happen to the 
jadgmentthe Eye paflTeth upon the diftance of ObjedsJ I cal» 
led into the room fome unconcerned perfoniSj wholly ignorant 
what the Experiment aiiiied at ^ and demanding whether they 
fa w not the coloured Si! ks and Ruier in a crooked line ? t hey 
anfwered in the negative. 
5. The next Experiment I made in ancompounded Co- 
Jour5 (as Mr. iVVwr(?;^ terms them, Prop $ & 13.] as follows. 
Having caft tv/o coloured Images upon the Wall, fo as the 
Scarlet colour of theonedidfall in a ftreight line (parallel to 
the Horizon) with the Violet of the other 1 I then looked up- 
on both throughanother Prifnijand found them ftill appear in 
aftreighc line parallel to the Horizon, as they had fbrmerly 
done to the naked eye. Now according to Mr. Newtop^'s AC* 
fertion of different refi-angibility in different Rays, I con- 
ceive the Violet rays ftiould fuffer a greater refraftion in the 
Prifm at the eye^ than the Scarlet ones, and confequently both 
-colours lliould not appear in aft reight line parallel to the Ho- 
rizon. 
6. Another EKperiment I made in order to fome further 
difcovery of that furprizing PhmofHemn of the coloured 
Image, which occafioned Mt.Nemom ingenious Theory of 
Li^htdX\d Colours ^ as alfo his excellent invention of the re- 
flefling telefcope and Microfiope. Having then fometimes fuf- 
pefled,that not only thedireft Sun-beams, but alfo other ex« 
trafteous light might pofiibly influence the coloured SpeBrum^ 
I hoped to difcover the truth of this fufpicion by means of 
the Sun-fpots, made to appear in the coloured Image by placing 
a Telefcope behind the Prifm. But my endeavours proving 
jneffefiual hereinby reafon of fome intervening difficulties , I 
thought at length of more feafible method in order to the 
defigned difcovery, as in the following Experiment. 
J fattened a very white Paper .Circle (about an inch in dia- 
Titeter) upon my Window-^lhut^ \ and beholding it through m^ 
IPrifm, I found a Coloured image painted thereby upon my 
Rttim^ anfwerabtein almoft all refpefis to the former of the 
Yyyy Sun 
