— r S093 ) 
dilate a Linear ray into a Superficial, the Crofs refraaions ot 
thzt/econd Priftne ought by further fplitting to dilate and draw 
that Superficial ray into a PyramidaHolid. But, upon tryai, 
I found it otherwile 5 the Image being as regularly Ob- 
long as before, and inclia'd to both the Prifmes at an angle of 
4 5» degrees. 
1 tryed aUo all other Pofitions of the fecond Prifnae, by tur- 
ning the Ends about its middle part; and in no cafe could cb^ 
lerve any (uch Irregularity. The Image was ever alike incli- 
ned toboth Prifmes, its Breadth anfwering to the Suns Dia« 
meter, and its length being greater or lefs accordingly as the 
Refraftions more or left agreed , or contradidled one ano- 
iher^ ^ , ^ , ^ 
And by thefe Obfervations, fince the Breadth of the Image 
was not augmented by the Crofs refradion of the fecondPxiimc^ 
that refraftion muft have been performed mthout any fplitting 
or dilating of the ray j and therefore at leaft the Light inci- 
dent on that Prifme muft be granted an Aggregatof Rays un- 
equaHj refrangible in my kofe. And fioce the Image was c- 
qually inclio'd to both Prifmes, and confequently the Refra- 
ftions alike in both, it arguesjthat they were perform'd accor- 
ding^^ome Conflant Law without any irregularity, 
^o determine the Quae- ^ . . , . 
X 1 ^ ^ r c 9» That there art m&n than WoOmi- 
rejthe Ammadverfor ret errs to an aiors. 
Experiment made with two 
Wedge-like boxes, recited in the M/Vr^^gr^:^^ of the Ingenious 
Mr* Ho^^^ Obferv. lo* pag. 75. the defign of which was to 
produce all Colours out of a mixture of tipo^ But there is, I 
Conceivej a double defeA in this inftance» For, it appears 
not, that by this Experiment all colours can be produced out 
of two 5 and, if they could^ yet the Inference would not fol- 
low- 
That^// Colours cannot by that Experiment be produced 
out of two^ Will appear by confideriog, that the Tindiarc of 
^/w, which afforded one of thofe Colours, was not all over 
of one uniform colour, but appear'd ^'^//^^n? near the edge of 
the Box,and red at other pi aces where it was thicker: ^Sotd'wg 
all variety of colours (romzpale yellm to a deep red orScarler, 
according to the various thicknefs of the liquor. And fa the 
Lllill 2 Iblutio}^ 
