Besides these, there are a lesser sort; which, by the help of a _Microscope_, also appear, if not to be fill’d up with a _Pith_, yet to contain certain light and filmy parts, more or fewer, of a _Pithy_ nature within them. And these are all the Pores the best Glasses, which, (when upon these Enquiries) we had at hand, would shew us. But the Learned and most Ingenious Naturalist Mr. _Hook_ sheweth us moreover, besides these, a third, and yet smaller sort; the description whereof I find he hath given us amongst his _Microscopical Observations_. Of these Pores (as a confirmation of what, in the Second Chapter, I have said of the Pores of the _Lignous Body_ in general) he also demonstrates; that they are all continuous and prolonged by the length of the _Trunk_; as are the greater ones; the Experiment whereof he imparteth to be, by filling up, suppose in a piece of _Char-coal_, all the said Pores with _Mercury_; which appears to pass quite through them, in that by a very good Glass it is visible in their Orifices at both ends; and without a Glass, by the weight of the Coal alone, is also manifest. Upon farther Enquiry, I likewise find, that the Pores of the _Lignous Body_ in the _Trunk_ of Plants, which at first only supposed, by the help of good Glasses are very fairly visible; each Fibre being perforated by 30, 50, 100, or hundreds of Pores. Or what I think is the truest notion of them, that each Fibre, though it seem to the bare eye to be but one, yet is indeed a great number of Fibres together; every Pore being not meerly a space betwixt the several pores of the Wood, but the Concave of a Fiber: So that if it be asked, what all that part of a Vegetable, either Plant or Tree, which is properly call’d the woody part; what all that is, I suppose, that is nothing else but a Cluster of innumerable and most extraordinary small Vessels or concave Fibres. See _Fig. 15_. Next the Insertions of the _Cortical Body_, which in the _Trunk_ of a Tree saw’d athwart, are plainly discerned as they run from the Circumference toward the Center; the whole Body of the Tree being visibly compounded of two distinct Substances, that of the several Rings, and that of the Insertions, running cross; shewing that in some resemblance in a Plain, which the Lines of Latitude and of the Meridian do in a Globe. See _Fig. 16_. These Insertions are likewise very conspicuous in Sawing of Trees length-wayes into Boards, and those plain’d, and wrought into Leaves for Tables, Wainscot, Trenchers, and the like. In all which, as in course Trenchers made of _Beech_, and Tables of Oak, there are many parts which have a greater smoothness than the rest; and are so many inserted pieces of the _Cortical Body_; which by reason of those of the _Lignous_, seem to be discontinuous; although in the _Trunk_ they are extended throughout its Breadth.