(694) 
thcn,br wholly overthrow the fame. The Experiments I pitch- 
ed upon for this purpofe, are as follow : 
1. Having frequently obferved , that the form of Objefls 
viewed in the Microfcope (or rather of the Microfcope it felf ) 
confifts almoft in an indivifiblc point, I concluded , two very 
fmall pieces of Silk, the one fcarlec, the other violet colour, 
placed near together, fiiould,according to Mr. Nervtons Theo- 
ry, appear in the Microfcope in a very different degree of 
clarity, in regard their unequal refrangibility rouft caufethe 
fcarlet rays or fpecies to over-reach the Ketim , while placed 
in the due focus of the violet ones, and confequently muft oc- 
. cafion a fenfible confufion in the vifion of the former , one and 
the fame point of the Scarlet objeft affefling feveral nerves in 
the Retina. Yet upon frequent trials I have not been able to 
perceive any inequality in this point. 
2. The fecond Experiment I made in Water* I took a 
brafs Ruler, and fafteniog thereunto feveral pieces of Silk, red, 
yellow, green, blew and violet, I placed it at the bottom of a 
fquare velTel of Water : then I retired from the Vefiel fafar as 
^ not to be able to fee the aforefaid Ruler and coloured Silks 
otherwife than by help of the refrafted Ray. Now, did Mr. 
iVifirWs doftrine hold, I conceiv'd, I fliould not fee all the 
mentioned Colours in a ftreight line with the Ruler , in regard 
the unequal refrangibility of different Rays rouft needs dif- 
place fome more than others* Yet in effeft,upon many Trials, I 
conftantly found them in as ftreight a line as the bare Ruler had 
appeared in. 
3. Toajdvance this Experiment, I adjoyneda fecond refra- 
ftion to the former of the Water, by placing my Prifm fo as to 
receive ferpendkuUrly the refrafled Jpecies of the Silk and 
Ruler 5 whereby only the emergent ^^^/Vi fuffered a fccond 
refraflion. But ftiil with equal fuccefs, as to their appearing in 
altraight line, to the eye placed behind the Prifm. 
4. To ihefe two .Refraftions I further added a third, by 
receiving the coloured fptc\t$Miquelj upon the Prifm 5 w&re- 
by both incident and emergent Jpecies fufFered their re(peftive 
refrafiions. But ftill with the lame fuccefs as formerly, as to the 
ftreight line they appeared in* 
For 
