Micrographia - Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon by Robert Hooke
page 159 of 465 (34%)
page 159 of 465 (34%)
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that unless there be found some way of comminuting them into less bulks
then the liquor does dissolve them into, all the Rays that pass through them must necessarily receive a tincture so deep, as their appropriate refractions and bulks compar'd with the proprieties of the dissolving liquor must necessarily dispose them to empress, which may perhaps be a pretty deep Yellow, or pale Red. And that this is not _gratis dictum_, I shall add one instance of this kind, wherein the thing is most manifest. If you take Blue _Smalt_, you shall find, that to afford the deepest Blue, which _cæteris paribus_ has the greatest particles or sands; and if you further divide, or grind those particles on a Grindstone, or _porphyry_ stone, you may by _comminuting_ the sands of it, _dilute_ the Blue into as pale a one as you please, which you cannot do by laying the colour thin; for wheresoever any single particle is, it exhibits as deep a Blue as the whole mass. Now, there are other Blues, which though never so much ground, will not be _diluted_ by grinding, because consisting of very small particles, very deeply ting'd, they cannot by grinding be actually separated into smaller particles then the operation of the fire, or some other dissolving _menstruum_, reduc'd them to already. Thus all kind of _Metalline_ colours, whether _precipitated_, _sublim'd_, _calcin'd_, or otherwise prepar'd, are hardly chang'd by grinding, as _ultra marine_ is not more _diluted_; nor is _Vermilion_ or _Red-lead_ made of a more faint colour by grinding; for the smallest particles of these which I have view'd with my greatest Magnifying-Glass, if they be well enlightned, appear very deeply ting'd with their peculiar colours; nor, though I have magnified and enlightned the particles exceedingly, could I in many of them, perceive them to be transparent, or to be whole particles, |
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