scurff

Growing Trees also, and any kinds of Woods, Stones, Bones, &c. that have been long expos'd to the Air and Rain, will be all over cover'd with a greenish scurff, which will very much foul and green any kind of cloaths that are rubb'd against it; viewing this, I could not certainly perceive in many parts of it any determinate form, though in many I could perceive a

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