The same put under water for a night, and somewhat more, became transparent, and the superficies being wiped dry, weighed 6³⁄₂₅₆ _Grains_.
The difference between these two weights, 0⁵⁰⁄₂₅₆ of a _Grain_.
The same Stone kept out of water one Day and becoming cloudy again weighed, 5²²⁵⁄₂₅₆ _Graines_.
Which was more then the first weight, 0¹⁶⁄₂₅₆ of a _Grain_.
The same being kept two Days longer weighed, 5²⁰²⁄₂₅₆ _Graines_.
Which was less then at first, 0⁷⁄₂₅₆ a _Grain_.
Being kept dry something longer it did not grow sensibly lighter.
Being put under water for a night and becoming again transparent and wiped dry, the weight was, _6³⁄₂₅₆ Grains_, the same with the first after putting in water, and more then the last weight after keeping of it dry, 0⁵⁷⁄₂₅₆ of a _Grain_.
Another Stone of the same kind being variegated with milky _white_ and _gray_ like some sorts of _Agates_, while it lay under water, was alwaies invironed with little Bubbles, such as appear in water a little before boyling, next the sides of the Vessel.
There were also some the like Bubbles on the Surface of the water just over it, as if either some exhalations came out of it, or that it did excite some fermentation in the parts of the water contiguous to it.
There was little sensible difference in the transparency of this Stone, before the putting under water, and after: To be sure the milky-_white_ parts continued as before, but more difference in weight then in the former. For whereas before the putting into the water the weight was 18⁹⁷⁄₁₂₈ _Graines_. After it had lyen in about four and twenty hours the weight was 20²⁷⁄₁₂₈ _Graines_, so the difference was, 1⁵⁸⁄₁₂₈ _Graines_.
The same Stone was infused in the water scalding hot, and so continued for a while after it was cold, but got no more weight then upon infusing in the cold, neither was there any sensible Difference in the weight both times.
In which Experiment, there are three Observables that seem very manifestly to prove the porousness of these seemingly close bodies: the first is their acquiring a transparency, and losing their whiteness after steeping in water, which will seem the more strongly to argue it, if what I have already said about the making transparent, or clarifying of some bodies, as the white powder of beaten Glass, and the froth of some glutinous transparent liquor be well consider’d; for thereby it will seem rational to think that this transparency arises from the insinuation of the water (which has much the same refraction with such stony particles, as may be discover’d by Sand view’d with a _Microscope_) into those pores which were formerly repleat with air (that has a very differing refraction, and consequently is very reflective) which seems to be confirm’d by the second Observable, namely, the increase of weight after keeping, and decrease upon drying. And thirdly, seem’d yet more sensibly confirm’d by the multitude of bubbles in the last Experiment.