( ) 
Experiment II. 
Inftead of the red or blue Paper at rr (Fit. i, z, and 
ha f £ a L, ^R A r- PlCCe R ’ 3 Pa P erhap ' red, and 
fore Pzr ’f !. R n — 4 ;) then over the Hole in the 
re t art of the Box reprefented by e g (Fig. z.) I fi xec l 
iguare P ate « d (Fig. 4 .) iitlf an fblojig Hole 
one In I / nches i ° ng , m its HorJzontal Pofition, and 
one Inch deep, through which one might fee the parti- 
coloured Paper, as if it was only of the Bignef S P and 
thTrifl tb ‘h . A P ertlare ’ and ftrongly enlighten’d by 
the Candles hid in the Box; the reft of the Room 
being very dark N. B. I made this T reparation, be- 
aufe Rizzetti objebls to Sir Ifaac Newton’s fir!} Expe 
riment of the firft Book, that the black Cloth beyond 
the parts- co loured Taper, was not colourlefs, J and 
therefore the Experiment was not decijive as parti, 
cularly relating to the Taper. J * m 
R R J:, ^< ? ',^‘ sthePa P ercontrafl ed in Length and 
Breadth by the Aperture of the Plate, which" Paper 
being looked at, at the Diftance of five Foot, by the 
Pnfm i, appeared as drawn at r b. The Prifm beintr 
removed to x, at the Diftance of ten Foot, Ihewed 
the Paper as at : r b. And when it was kt 3 (ft 
he Diftance of fifteen Foot) the Paper appeared as i f 
In thefe three Cafes the blue b, b, and /3 appeared 
lower than the red r, r ? , the refrafting Angle of the 
Pnfm being downwards. When the refraffL Ande 
was held upwards, as at y, then the Blue°B was 
rafted higher than the red R ; but if due Care be not 
taken,in turning the Prifm,aRefledionmay bemiftaken 
-or a Refrafhon, as at 4; and then indeed the Red 
Mm mm ' and 
