This Observation seems to afford us the true reason of several Phaenomena of Coals; as

First, why they look black; and for this we need go no further then the Scheme, for certainly, a body that has so many pores in it as this is discover’d to have, from each of which no light is reflected, must necessarily look black, especially, when the pores are somewhat bigger in proportion to the intervals then they are cut in the Scheme, black being nothing else but a privation of Light, or a want of reflection; and wheresover this reflecting quality is deficient, there does that part look black, whether it be from a porousness of the body, as in this Instance, or in a deadning and dulling quality, such as I have observ’d in the Scoria of Lead, Tin, Silver, Copper, &c.

Next, we may also as plainly see the reason of its shining quality, and that is from the even breaking off of the stick, the solid interstitia having a regular termination or surface, and having a pretty strong reflecting quality, the many small reflections become united to the naked eye, and make a very pretty shining surface.

Thirdly, the reason of its hardness and brittleness seems evident, for since all the watery or liquid substance that moistn’d and toughn’d those Interstitia of the more solid parts, are evaporated and remov’d, that which is left behind becomes of the nature almost of a stone, which will not at all, or very little, bend without a divulsion or solution of its continuity.

It is not my design at present, to examine the use and Mechanisme of these parts of Wood, that being more proper to another Enquiry; but rather to hint, that from this Experiment we may learn,

First, what is the cause of the blackness of many burnt bodies, which we may find to be nothing else but this; that the heat of the fire agitating and rarifying the waterish, transparent, and volatile water that is contain’d in them, by the continuation of that action, does so totally expel and drive away all that which before fill’d the pores, and was dispers’d also through the solid mass of it, and thereby caus’d an universal kind of transparency, that it not onely leaves all the pores empty, but all the Interstitia also so dry and opacous, and perhaps also yet further perforated, that that light onely is reflected back which falls upon the very outward edges of the pores, all they that enter into the pores of the body, never returning, but being lost in it.

Now, that the Charring or coaling of a body is nothing else, may be easily believ’d by one that shall consider the means of its production, which may be done after this, or any such manner.  The body to be charr’d or coal’d, may be put into a Crucible, Pot, or any other Vessel that will endure to be made red-hot in the fire without breaking, and then cover’d over with Sand, so as no part of it be suffer’d to be open to the Air, then