First, in that it had a very little solid substance, in comparison of the empty cavity that was contain’d between, as does more manifestly appear by the Figure A and B of the XI. _Scheme_, for the _Interstitia_, or walls (as I may so call them) or partitions of those pores were neer as thin in proportion to their pores, as those thin films of Wax in a Honey-comb (which enclose and constitute the _sexangular celts_) are to theirs. Next, in that these pores, or cells, were not very deep, but consisted of a great many little Boxes, separated out of one continued long pore, by certain _Diaphragms_, as is visible by the Figure B, which represents a sight of those pores split the long-ways. I no sooner discern’d these (which were indeed the first _microscopical_ pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this) but me thought I had with the discovery of them, presently hinted to me the true and intelligible reason of all the _Phænomena_ of Cork; As, First, if I enquir’d why it was so exceeding light a body? my _Microscope_ could presently inform me that here was the same reason evident that there is found for the lightness of froth, an empty Honey-comb, Wool, a Spunge, a Pumice-stone, or the like; namely, a very small quantity of a solid body, extended into exceeding large dimensions. Next, it seem’d nothing more difficult to give an intelligible reason, why Cork is a body so very unapt to suck and drink in Water, and consequently preserves it self, floating on the top of Water, though left on it never so long: and why it is able to stop and hold air in a Bottle, though it be there very much condens’d and consequently presses very strongly to get a passage out, without suffering the least bubble to pass through its substance. For, as to the first, since our _Microscope_ informs us that the substance of Cork is altogether fill’d with Air, and that that Air is perfectly enclosed in little Boxes or Cells distinct from one another. It seems very plain, why neither the Water, nor any other Air can easily insinuate it self into them, since there is already within them an _intus existens_, and consequently, why the pieces of Cork become so good floats for Nets, and stopples for Viols, or other close Vessels.