First, That all kind of _fiery burning Bodies_ have their parts in motion, I think, will be very easily granted me. That the _spark_ struck from a Flint and Steel is in a rapid agitation, I have elsewhere made probable. And that the Parts of _rotten Wood_, _rotten Fish_ and the like, are also in motion, I think, will as easily be conceded by those, who consider, that those parts never begin to shine till the Bodies be in a state of putrefaction; and that is now generally granted by all, to be caused by the motion of the parts of putrifying bodies. That the _Bononian stone_ shines no longer then it is either warmed by the Sun-beams, or by the flame of a Fire or of a Candle, is the general report of those that write of it, and of others that have seen it. And that heat argues a motion of the internal parts is (as I said before) generally granted. But there is one Instance more, which was first shewn to the _Royal Society_ by Mr. _Clayton_ a worthy Member thereof, which does make this Assertion more evident then all the rest: And that is, That a _Diamond_ being _rub’d_, _struck_ or _heated_ in the dark, shines for a pretty while after, so long as that motion, which is imparted by any of those Agents, remains (in the same manner as a Glass, rubb’d, struck, or (by a means which I shall elsewhere mention) heated, yields a sound which lasts as long as the vibrating motion of that _sonorous_ body) several Experiments made on which Stone, are since published in a Discourse of Colours, by the truly honourable Mr. _Boyle_. What may be said of those _Ignes fatui_ that appear in the night, I cannot so well affirm, having never had the opportunity to examine them my self, nor to be inform’d by any others that had observ’d them: And the relations of them in Authors are so imperfect, that nothing can be built on them. But I hope I shall be able in another place to make it at least very probable, that there is even in those also a Motion which causes this effect. That the shining of _Sea-water_ proceeds from the same cause, may be argued from this, That it shines not till either it be beaten against a Rock, or be some other wayes broken or agitated by Storms, or Oars, or other _percussing_ bodies. And that the Animal _Energies_ or Spirituous _agil_ parts are very active in _Cats eyes_ when they shine, seems evident enough, because their eyes never shine but when they look very intensly either to find their prey, or being hunted in a dark room, when they seek after their adversary, or to find a way to escape. And the like may be said of the shining _Bellies of Gloworms_; since ’tis evident they can at pleasure either increase or extinguish that Radiation.