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silver was driven up again, and consequently, the Air above it was restored to its former density; upon which, the rotten Wood also recover'd its light. What the greatest Expansion of this Air was, we could not certainly determine, because the Expansion raised the external Quicksilver so high, as to hinder us to see and measure it. But we guessed, that the Air reached to about a foot or more from the top of the Pipe to the surface of the Quicksilver near the bottom of it. But when that ratified Air was impell'd into its former dimensions, we measured it, and found, that' the upper part of the Tube, unpossest by the Quicksilver, was about three inches; and the Wood being about an inch long, there remained two inches or somewhat better for the Air. But this Experiment is to be repeated, when exacter Instruments can be procured.
Experiment X.
Thinking it fit to try, as well, Whether stinking Fish that shines be of the same nature, as to Luminousness, with rotten Wood that shines too; as, whether the withdrawing of the Air will extinguish or eclipse the Light of a considerable bulk of luminous matter, as in the Experiments hitherto made, we found it would do to a small one: We took a Fish that we had kept, and caused to be watched 'till 't was almost all over Luminous, though much more in the Belly, and some parts of the Head, than elsewhere: And having suspended him in a conveniently shaped Receiver, we found him to give so great a light, that we suspected beforehand, that the withdrawing of the Air would. hardly have its full operation upon a Body, whole bulk was considerable, as well as its light very vivid, and which had many luminous parts retired to a pretty distance from the Air. Accordingly having exhausted the Receiver as much as we were wont, it appeared indeed, especially towards the latter end of the operation, that the absence of the Air did considerably lessen, and in some places eclipse the light of those parts that shone less strongly. But the Belly appeared not much less luminous than before: Wherefore supposing, that upon the turning of the Stop-cock, the Air coming in much more hastily than it could be drawn out, we should have the bell advantage to discern, what interest it had in the Lumi-
