And since we find that the great reason of the _Phænomena_ of this pretty _petrifaction_, are to be reduc’d from the gravity of a fluid and pretty volatil body impregnated with stony particles, why may not the _Phænomena_ of Ebullition or Germination be in part possibly enough deduc’d from the levity of an impregnated liquor, which therefore perpendicularly ascending by degrees, evaporates and leaves the more solid and fix’d parts behind in the form of a Mushrom, which is yet further diversify’d and specificated by the forms of the parts that impregnated the liquor, and compose or help to constitute the Mushrom. That the foremention’d Figures of growing Salts, and the Silver Tree, are from this principle, I could very easily manifest, but that I have not now a convenient opportunity of following it, nor have I made a sufficient number of Experiments and Observations to propound, explicate, and prove so usefull a _Theory_ as this of Mushroms: for, though the contrary principle to that of _petrify’d_ Iceicles may be in part a cause, yet I cannot but think, that there is somewhat a more complicated cause, though yet Mechanical, and possible to be explain’d. We therefore have further to enquire of it, what makes it to be such a liquor, and to ascend, whether the heat of the Sun and Air, or whether that _firmentiation_ and _putrifaction_, or both together; as also whether there be not a third or fourth; whether a Saline principle be not a considerable agent in this business also as well as heat; whether also a fixation, precipitation or settling of certain parts out of the aerial menstruum may not be also a considerable coadjutor in the business. Since we find that many pretty beards or _stiriæ_ of the particles of Silver may be precipitated upon a piece of Brass put into a _solution_ of Silver very much diluted with fair water, which look not unlike a kind of mould or hoar upon that piece of metal; and the hoar frost looks like a kind of mould; and whether there may not be several others that do concurr to the production of a Mushrom, having not yet had sufficient time to prosecute according to my desires, I must refer this to a better opportunity of my own, or leave and recommend it to the more diligent enquiry and examination of such as can be masters both of leisure and conveniencies for such an Enquiry.