The works of the Honourable Robert Boyle, Esq., epitomiz'd by Richard Boulton ... ; illustrated with copper plates.

CHAP. V. An Invention for estimating the Weight of Water in Water, with ordinary Ballances or Weights. Communicated in the Pub. Transact. of Aug. 16. 1669.

A Bubble about the bigness of a Pullet's Egg, with a long Stem turned upo at the end, was heated; and, when the Air was most of it expelled, sealed up; and then being by a con∣venient weight of Lead immersed under Water, it was suspended at the end of a Ballance, and counterpoised; and then the Apex of the Stem being broke off with a Forceps, so much

Water got into the Cavity of the Bubble, as required four drachms and thirty eight grains to reduce the Ballance to an Aequilibrium. Which being done, we drove out the Water by the help of a Flame of a Candle into another Glass, which was counterposed, and we found that it weighed four drachms and thirty grains, which together with what was evaporated and lost, and the weight of the Apex, amounted to the weight first mention'd. So that from hence it appears, that Water weights as much in Water, as it does in the open Air; which according to the best Computation we could make, succeed∣ed a second time in a larger Bubble.

As for the Objections which Mr. George Sin∣clair hath made to this Experiment, since it is the Opinion of our Author, that he only dif∣fers from him in Expressions, I shall wave what he there says, as not at all requisite in this Place; and shall only add what our Author hath said, to explain what he means by Water weigh∣ing in Water, viz. That it gravitates or weighs, in as much as it tends downwards, upon the account of its specifick Weight, tho' it does not preponderate, that is, the Parcel of Water weighed hath but an equal Tendency down∣wards with the Ambient Water, but upon an additional Weight it preponderates as much as the additional weight increases its Tendency towards the Center.