MicroGRaPaTA, 6 
\  fhall be @enerated feveral confecutions of colours, whofe order from thé 
thin end towards the thick, fhall be YeHom, Red Purpley Blue,Green's Telow; 
Red,Purple,Blue,Green 5 Tellow,Red,Purple,Blie;Greens rellow,&cland thefe 
fo often repeated, as the weaker pullfe does Jofe’ paces with its Primary, 
or firft pulfe, and is coincident with a fecond, third; fourth, fifth fixth iG. 
pulfe behind the firft. And this, as it is cormcident}or follows fiom the 
firft Hypothefis 1 took of colours,fo upon exeriment have'l found it in‘ mule 
titudes of inftances that feem to prove it. One thing which feems of the 
greateft concern in this cg is to determine the. greateft or leaft 
thicknefs requifite for thefe effects, which; though Thave not beet want- 
ing in attempting, yet fo exceeding thin are thefe coloured Plates, and {0 
imperfect our Atzcrofcope,that Ihave not been hitherto fuecefsfull,though 
if my endeavours fhall anfwer my expeCtations,] fhall hope to gratifie the 
curious Reader with fome things more remov'd-beyond our teach 
hitherto. ie galas: eaten lt 
_ . Thus have I,with as much brevity as I was able, endeavoured to expli- 
cate (Hypothetically at léatt) the caufes of the Phenowens 1 formerly rex 
cited, on the confideration of which I have been'the mote particular. 
Firft, becaufe I think thefe I have newly given are’capable of expli- 
cating all the Phenomena of colours, not onely of thofe appearing'in the 
Prifme, Water-drop, or Rainbow, and in laminated or plated bodies, but 
of all that are in the world, whether they be fluid or folid bodies, whe 
ther in thick or thin, whether tranfparent, of feemingly op cous, a9 I 
fhall in the next: Obfervation further endeavour to fhew. And fecondhy eb 
becaufe this being one of the two ornaments of all bodies difcov le 
by the fight, whether looked on with, ‘or:without a AGerofeope, "it feem’d 
to deferve (fomewhere in this Tract; which contains a‘ defcription of the 
Figure and Colour of fome minute bodies) to be fomewhat the more in- 
timately enquir'd into. . 
Aving inthe former Difcourfe, fromthe Fundamental caufe of Co# 
t J lour, made it probable, that thereare but two Colours, and {hewnj | 
that the Phamtafm of Colour is caus'd by'the fenfation of the oblique'or 
uneven pulfe of Light which is capable of no more varieties than two 
that arife from the two fidesof the oblique pulle, though each of thofe 
be capable of infinite gradations or degrees (each of them beginning 
from White, and ending the one inthe deepeft Scarletor tellow, the other 
inthe deepeft' B/ne) 1 thall in this Sedion fet down tome Obfervations 
whichI have made of other colours, fuch as Jsetaline powders 
or colour'd. bodies and feveral kinds. of tin@tures or ting’d liquors, all 
which, together with thofe [treated of in the former: Obfervation will, 
Tfuppofe; comprife the feveral fubjedts in: which. colour isobferv'd ‘to 
beinherent, ahd the fevetal manners by se is _— ‘ 
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