Page:Philosophical Transactions - Volume 004.djvu/115

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he hath gratified the Ingenious abroad. And it will doubtless be the more welcome; for as much as no body, we know of, hath so much as attempted to determine, How much Water may weigh in Water; and possibly if such a Problem had been propos'd , it would have been Iudged impracticable.

The Method or Expedient, he made use of to perform it as near as he could, may be easily learned by the ensuing accompt of a Tryall or two, he made for that purpose, which among his Notes he caused to be registred in the following words.

A Glass-butle of about the bigness of a pullets-egg was purposely blown at the flame of a Lamp, with a somewhat long stem turn'd up at the end, that it might the more conveniently be broken off. This Buble being well heated to rarify the Air, and thereby drive out a good part of it, was nimbly sealed at the end, and by the help of the figure of the stem was by a convenient Weight of Lead depressed under water, the Lead and Glass being tyed by a string to one Scale of a good Ballance, in whose other there was put so much weight, as sufficed to counterpoise the Buble, as it hung freely in the midst of the water. Then with a long Iron forceps I carefully broke off the seal'd end of the Buble under water, so as no Buble of Air appear'd to emerge or escape through the water; but the liquor by the weight of the Atmosphere sprung into the un-replenisht part of the Glass-buble, and fill'd the whole cavity about half full; and presently, as I foretold the Buble subsided and made the Scale, 'twas fastned to, preponderate so much, that there needed 4. drachms and 38. graines no reduce the Ballance to an Æquilibrium. Then taking out the Buble with the water in't, we did, by the help of rite Hame of a candle, warily apply'd, drive out the water (which otherwise is not easily excluded at a very narrow stem) into a Glass counterpoised before; and we found it. as we expected, to weigh about 4. dramchs and 30 graines, besides some little that remained in the Egg, and some small matter that may have been rarified into vapors, which added to the piece of Glass that was broken off under water and lost there, might very well amount to 7. or 8. graines. By which it appears not only, that water hath some weight in water, but thatit