opacousness

_Porphyry_, or _Serpentine_, the small particles will by reason of their flaws, appear perfectly _opacous_; and that 'tis the flaws that produce this _opacousness_, may be argued from this, that particles of the same

Micrographia Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon Robert Hooke 1669

_opacousness_, as I said before, proceeding from the particles, being very much flaw'd, unless we were able to joyn and re-unite those flaw'd particles again into one piece, we shall not be able to deepen the colour, which since we are unable to do with most of the colours which are by

Micrographia Some Physiological Descriptions of Minute Bodies Made by Magnifying Glasses with Observations and Inquiries Thereupon Robert Hooke 1669