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perfe& whites not in fpeciy OJ C?lCUs bLlt oil-<br />
$7’ in degree of ILuminoufnels, 1:. is lnanifeit<br />
r$at there is nothing more rcqLufltc to maBe<br />
whites, and differ from them only in the qwn-<br />
(that which was compounded of Orpiment, Purment<br />
;.\, and by it, in the fhadow, 1 laid a piece<br />
of white Paper of the fame bi~nei:. Then going<br />
To afl?ga the Proportions accurately may be<br />
difficult, by reafon of the difkrent good&s of<br />
pounders of the Same kind. Accmdiqgly as the<br />
C&L~~ of ally Powder is more or 14s f~111 anti<br />
IL~~~.~J,oL~s, it ought to be ufcd in a lefs or greater<br />
proportion.<br />
~4~0~7 confidering thk thek grey and dun Co-<br />
IOLII-s Inay be alfo produced by mixi.ng whites<br />
alld b]&s, and by confe‘egue,we d.ifkr from<br />
t]lem perfeAly white than to increafc their L&t<br />
SLr@icicntly ; and, on the contrary., if by increafing<br />
thei.r J+ight they can be broLight to perk8<br />
whitciiefs, it will thence alfo follow, that they<br />
are ‘of the faixe fpccies of \CO~OLU: with the heft<br />
tity of Light. And this I tried as follows. T to&<br />
the third of the abovemention’d .groy Mixtures<br />
plq Bifc, and ?%ide .&iris) arid r,ctbbcd<br />
ly upon the Floor of my Chamber,<br />
,Sun fhone upon it throu~li the opened<br />
it thickwhere<br />
the<br />
Cafefrom<br />
them to the diitance of ~2 OY I 211Jcet , fo<br />
that I could noi difcern the ~~nc;~fwmfs of the<br />
Surface ‘of the Powder, nor the iittk Sl~dm<br />
let fall from the gritty Particlcs tlrcruof; the<br />
Powder appeared intenfely whi tc, i0 as to<br />
fcend even the Paper it felf,in whitcncf~,<br />
cially if the Paper were a I.ittle ~~NGxI fi~~n<br />
trane@e-<br />
thd<br />
J$ght of the Clouds, and the13 the
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