MicroGRAPHia. 
_ Thus, if you takea piece of tranfparent Glafs that is well colour’d, and 
by heating it, and then quenching it in Water, you flaw it allover; 
it will become opacous, and will exhibit the fame colour with which the: 
piece is ting d, but fainter and whiter. ah 
Or, if you take a Pipe of this tranfparent Glafs, and inthe flame of a 
Lamp melt it, and then blowit into very thin bubbles, then break thofe 
bubbles, and collect a good parcel of thofe’ amine together in aPaper, 
you fhall find that a {mall thicknefs of thofe Plates will conftitute an opa- 
cous body, and that you may fee through the mafs of Glafs before it be 
thus /aminated, above four times the thicknefs:, And befides, they will 
now afford.a colour by reflection as other opacous (as they are ‘call’d) 
colours will, but much fainter and whiter than that of the Lump or Pipe 
out of which they were made. | ; | 
Thus alfo,if you take Putty, and melt it with any tranfparent colour'd 
Glafs,it will make it become an opacous colour'd lump, and to yield a pa- 
ler and whiter colour than the lump by refleCtion.. lice 
_ The famething may be done by a preparation of Avtimony, ashas been 
fhewn by the Learned Phyficzax, ID" Cc. Az, in his Excellent Obfervations 
and Notes on Nery's drt of Gla/s; and by this means all tranfparent co« 
lours become opacous, or avzmels. And though by being ground they lofe 
very much of their colour, growing much whiter by reafon of the multi- 
tude of fingle reflections from their outward furface, as I fhew’d afore, 
yet the fire that in the nealing or melting re-unites them, and fo re- 
news thofe fpurious reflections, removes alfo thofe whitenings of the co- 
Jour that proceed from them. az 116 maBel Ya etdear ar 
_ As for the other colours which Painters ufe, which are tranfparent,and 
usd to’ varnifh over all other paintintings, ‘tis well enough known that 
the laying on of them thinner or thicker,does very much déluteor deepen 
their colour. y 
’ Painters Colours therefore confifting moft of them of folid particles, 
fo fmall that they cannot be either re-united. into thicker. particles by 
any Art yet known,and confequently. cannot bedeepned 5,or divided in- 
to particlés fo {mall as the flaw’d particles that exhibit that colour, much 
JefS into {maller, and confequently cannot be diluted ; It is neceflary that 
they whichare to imitate all kinds of colours, fhould have asmany de- - 
grees of each colour as can be procur'd. eifito 
- And to this purpofe, both Limners and Painters have avery great va- 
riety both of Yellows and Blues, befides feveral other colour'd bodies 
that exhibit very compounded colours, fuch asGreensand Purples; and 
others that are compounded of feveral degrees of Yellow, or feveral de- 
grees of Blue, fometimes unmixt, and fometimes compounded with fe= 
veral other colour’d bodies. | rt ns od aii 
The Yellows,’ fromthe paleft to ithe deepeft Red or Scarlet, which 
‘has no intermixture.of Blue, are pale and deep Mafticut, Orpament, 
Englifh Oker, bromn Oker, Red Lead, and Vermilion, burnt Englfh Oker, 
and burnt brown Oker,, which laft have a mixture of darks or dirty parts 
eh thera, Orrin vad Slone Oe: slog a 
ets 7 ; Theix 
17 
