stone call'd _Oculus Mundi_, as I find it preserv'd in the Records of that
Honourable Society.

A small stone of the kind, call'd by some Authours, _Oculus Mundi_,
being dry and cloudy, weigh'd 5-209/256 _Grains_.

The same put under water for a night, and somewhat more, became
transparent, and the superficies being wiped dry, weighed 6-3/256
_Grains_.

The difference between these two weights, 0-50/256 of a _Grain_.

The same Stone kept out of water one Day and becoming cloudy again
weighed, 5-225/256 _Graines_.

Which was more then the first weight, 0-16/256 of a _Grain_.

The same being kept two Days longer weighed, 5-202/256 _Graines_.

Which was less then at first, 0-7/256 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, _6-3/256 Grains_, the same with the first
after putting in water, and more then the last weight after keeping of
it dry, 0-57/256 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