Observ. 14.  Of frozen Figure.

The Figures of hoar Frost, and the Vortices on windows:  several Observations on the branched Figures of Urine:  the Figures of Regulus Martis stellatus_, and of Fern.  Of the Figures of Snow.  Of frozen water._

Observ. 15.  Of Kettering Stone.

A description of the Figure of the Particles, and of the Pores, and of the Contexture.  Several Observations and Considerations thereupon:  some Conjectures about the medium_ and propagation of light, and the constitution of fluid and transparent Bodies.  Several Experiments to prove the porousness of Marble, and some other Stones.  An account of some Experiments to this purpose made on an Oculus Mundi:  some other Considerations and Experiments about the porousness of Bodies:  some other Considerations about the propagation of light and refraction._

Observ. 16.  Of Charcoal.

Of two sort of Pores to be found in all Woods and Vegetables; the shape of them; the number, thickness, manner and use of these Pores.  An explication of the Phaenomena_ of Coals.  The manner of charring Wood, or any other body.  What part of Wood is combustible.  An Hypothesis of fire explicated in twelve particulars, wherein the Action of the Air, as a Menstruum in the dissolution of all sulphureous bodies, is very particularly explicated, and some other Considerations about the Air proposed:  the examination of a piece of Lignum fossile sent from Rome, and some Conclusions thence deduc’d._

Observ. 17.  Of Wood, and other Bodies, petrified.

Several Observations of divers kinds of these substances.  A more particular examination and explication of one very notable piece of petrified Wood; and some Conjectures about the cause of those productions:  several Observations made on other petrified Bodies, as shells, &c.  And some probable Conclusions thence deduc’d, about the original cause of those Bodies.

Observ. 18.  Of the Pores of Cork, and other Bodies.

Several Observations and Considerations about the nature of Cork:  the number of Pores in a cubical Inch, and several considerations about Pores.  Several Experiments and Observations about the nature of Cork:  the Texture and Pores of the Pith of an Elder, and several other Trees:  of the Stales of Burdocks, Teasels, Daisies, Carret, Fennel, Ferne, Reeds, &c. of the frothy texture of the Pith of a Feather:  some Conjectures about the probability of values in these Pores.  Argued also from the Phaenomena_ of sensible and humble Plant:  some Observations on which are inserted._

Observ. 19.  Of a Vegetable growing on blighted Leaves.

Several Observations and Examinations made of them:  several Considerations about spontaneous generation arising from the putrefaction of Bodies.

Observ. 20.  Of Blew Mould and Mushromes.