CXLVIII.MADAM,I Thank you for the Cup you sent me, but I cannot Guess whether it be Glass, Metal, or Stone, for it seems too Light to be Metal, too Thin to be Stone, and too Strong to be Glass, but I suppose it is of a Mix'd Nature, as many things are; as for Example, Feathers seem to be betwixt Hair and Wool, for the Quils seem to be somewhat like Soft Souls, being Hollow, and within them a Pith, somewhat like Brains, and the Small Sprigs of Feathers are like as Hair Growing thereupon, and Sprouting thereout, and the Downy part of Feathers which Grow towards the Bottom, or Root of the Quils, are of the Nature and Likeness of Wool; so the Scales of Fishes seem to be betwixt Sinews or Gristles, and Skin, for they are like Gristles in being Tough and Clammy, and like Skin in being Smooth, Slick, and Thinner than Sinews are; Also Horns of Beasts, Hoofs, and Claws, Bills of Fowls, and Nails of Men, are betwixt Bones and Gristles, as to be Harder than Gristles, and Softer than Bones. Also there are many se∣veral Creatures, which seem to be of a Mix'd Kind, as a Bat seems to be betwixt a Beast and a Bird, having a Body like a Mouse, and Wings like a Bird, and an Owl seems somewhat like 0