72 
_ the firefhould have 
MicrRoGRAPHIA., 
And this I find generally in moft 4etalline colours, that though they 
confift of parts fo exceedingly fmall,yet are they very deeply ting d,they 
being fo ponderous, and having fuch a multitude of terreftrial particles 
throng’d into a little room; fo that ‘tis difficult to find any particle tran 
parent or refembling a pretious ftone, though not impoflible; for Ihave 
obferv’d divers fuch fhining and refplendent colours intermixt with the 
particles of Ciznaber, both natural and artificial, before it hath been 
ground and broken or flaw'd into Vermiliex « As Ihave alfo in Orpiment, 
Red-lead, and Bife, which makes me fuppofe, that thofe metalline colours 
are by grinding, not onely broken and feparated actually into {maller 
pieces, but that they are alfo flaw'd and brufed ,whence they, for the 
moft part.become opacous,like flaw’d Cryftal or Glafs,cc. But for Saalts 
and verditures, Uhave been able witha AGicrofcope to perceive their par- 
ticles very many of them tranfparent. = 
_. Now, that the others alfo may be tranfparent, though they do not ap- 
pear fo to the Aéicrofcope,may be made probable by this Experiment : that 
if you take ammel that is almoft opacous, and grind it very well on 
a Porphyry, or Serpentine, the {mall particles will by reafon of their flaws, 
appear perfectly opacous; and that ‘tis the flaws that produce this opa- 
coufref., may be argued from this, that particles of the fame 4zzel much 
thicker if ehaee il appear fomewhat tranfparent evento the eye; 
id from this alfo, that the moft tranfparent and clear Cryftal, ST oe 
in the fire, andthen fuddenly quenched, fo that it be all over flaw'd, 
will-appear opacous and white, “ | 
And that the particles of Aetal/ine colours are tran{parent,may be argus 
ed yet further from this,that the Cryftals,or Vitriols of all Metals,are tranf 
parent, which fince they confift of metalline as well as falize particl 
thofe metalline ones ze be tranfparent, which is yet further joa i> 
from this, that they have for she mot part, app ropriate colours; fo the 
vitriol of Gold is Yellow ; of Copper.Blue, times Green; of Iron, 
green 5 of Tinn and Lead, a pale White; of Silver,a paleBlue,@c. 
And next,the Selytiox of all Metals into wenftruums are much the fame 
* with the Vitriols, or Cryftals, It feems therefore very probable, that — 
thofé colours which are made by the precipitation of thole particles out 
of the zenftrunmas by tranfparent precipitating liquors fhould be tranfpa+ 
aL 
rent alfo. Thus Gold precipitates with ol of Tartar, or {pirit of Uriuein= 
toa brown Yellow, Copper with na of Urize bes abies bkue, 
which retains its tranfparency. A 
or the Vitriol of Lead 
suinium whichis a kind 
- Athird Argument, 
being :calcin d,,and 
