Therefore twelfthly, it seems reasonable to think that there is no such thing as an Element of Fire that should attract or draw up the flame, or towards which the flame should endeavour to ascend out of a desire or appetite of uniting with that as its _Homogeneal_ primitive and generating Element; but that that shining transient body which we call _Flame_, is nothing else but a mixture of Air, and volatil sulphureous parts of dissoluble or combustible bodies, which are acting upon each other whilst they ascend, that is, flame seems to be a mixture of Air, and the combustible volatil parts of any body, which parts the encompassing Air does dissolve or work upon, which action, as it does intend the heat of the _aerial_ parts of the dissolvent, so does it thereby further rarifie those parts that are acting, or that are very neer them, whereby they growing much lighter then the heavie parts of that _Menstruum_ that are more remote, are thereby protruded and driven upward; and this may be easily observ’d also in dissolutions made by any other _menstruum_, especially such as either create heat or bubbles. Now, this action of the _Menstruum_, or _Air_, on the dissoluble parts, is made with such violence, or is such, that it imparts such a motion or pulse to the _diaphanous_ parts of the Air, as I have elsewhere shewn is requisite to produce light. This _Hypothesis_ I have endeavoured to raise from an Infinite of Observations and Experiments, the process of which would be much too long to be here inserted, and will perhaps another time afford matter copious enough for a much larger Discourse, the Air being a Subject which (though all the world has hitherto liv’d and breath’d in, and been unconversant about) has yet been so little truly examin’d or explain’d, that a diligent enquirer will be able to find but very little information from what has been (till of late) written of it: But being once well understood, it will, I doubt not, inable a man to render an intelligible, nay probable, if not the true reason of all the _Phænomena_ of Fire, which, as it has been found by Writers and Philosophers of all Ages a matter of no small difficulty, as may be sufficiently understood by their strange _Hypotheses_, and unintelligible Solutions of some few _Phænomena_ of it; so will it prove a matter of no small concern and use in humane affairs, as I shall elsewhere endeavour to manifest when I come to shew the use of the Air in respiration, and for the preservation of the life, nay, for the conservation and restauration of the health and natural constitution of mankind as well as all other aereal _animals_, as also the uses of this principle or propriety of the Air in chymical, mechanical, and other operations. In this place I have onely time to hint an _Hypothesis_, which, if God permit me life and opportunity, I may elsewhere prosecute, improve and publish. In the mean time, before I finish this Discourse, I must not