used in _Virginia_. A Relation of
Persons kill'd with Subterraneous _Damps_. Of the _Mineral_ of _Liege_,
yielding both _Brimstone_, and _Vitriol_, and the way of extracting
them out of it, used at _Liege_. An Account of Mr. _Boyle's_
Experimental _History_ of_ Cold.

* * * * *

_Some Observations and Experiments upon _May-Dew_._

That ingenious and inquisitive Gentleman, Master _Thomas Henshaw_, having
had occasion to make use of a great quantity of _May-dew_, did, by several
casual Essayes on that Subject, make the following Observations and Tryals,
and present them to the _Royal Society_. {34}

That _Dew_ newly gathered and filtred through a clean Linnen cloth, though
it be not very clear, is of a yellowish Colour, somewhat approaching to
that of Urine.

That having endevoured to putrefy it by putting several proportions into
Glass bodies with blind heads, and setting them in several heats, as of
dung, and gentle baths, he quite failed of his intention: for heat, though
never so gentle, did rather clarify, and preserve it sweet, though
continued for two moneths together, then cause any putrefaction or
separation of parts.

That exposing of it to the Sun for a whole Summer in Glasses, that hold
about two Gallons, with narrow mouths, that might be stopp'd with Cork, the
only considerable alteration, he observed to be produced in it, was, that
Store of green stuff (such as is seen in Summer in ditches and standing
waters) floated on the top, and in some places, grew to the sides of the
Glass.

That putting four or five Gallons of it into a half Tub, as they call it,
of Wood, and straining a Canvas over it, to keep out Dust and Insects, and
letting it stand in some shady room for three weeks or a month, it did of
itself putrefy and stink exceedingly, and let fall to the bottom a black
sediment like Mudd.

That, coming often to see, what Alterations appeared in the putrefaction,
He observed, that at the beginning, within twenty four hours, a slimy film
floated on the top of the water, which after a while falling to the bottom,
there came another such film in its place.

That if _Dew_ were put into a long narrow Vessel of Glass, such as formerly
were used for Receivers in distilling of _Aqua Fortis_, the slime would
rise to that height, that He could take it off with a Spoon; and when he
had put a pretty quantity of it into a drinking Glass, and that it had
stood al