quiring World to take notice, that
this subject, as it hath hitherto bin almost totally neglected, so it is
now, by this Excellent Author, in such a manner handled, and improved by
near _Two hundred_ choice _Experiments_ and _Observations_, that certainly
the _Curious_ and _Intelligent_ Reader will in the perusal thereof find
cause to admire both the Fertility of a Subject, seemingly so barren, and
the Author's Abilities of improving the same to so high a Degree.

But to take a short view of some of the particulars of this _History_, and
thereby to give occasion to _Philosophical_ men, to take this Subject more
into their consideration, than hitherto hath been done; the Ingenious
Readers will here see,

1, That not only all sorts of _Acid_ and _Alcalizate_ Salts, and Spirits,
even Spirit of Wine, but also Sugar, and Sugar of Lead mixed with Snow, are
capable of freezing other Bodies, and upon what account they are so.

2, That among the Substances capable of being frozen, there are not only
all gross sorts of Saline Bodies, but such also as are freed from their
grosser parts, not excepting Spirit of Urine, the _Lixivium_ of Pot-ashes,
nor Oyl of Tartar, _per deliquium_, it self.

3, That many very spiritous liquors, freed from their aqueous parts, cannot
be brought to freeze, neither naturally, nor artificially: And here is
occasionally mentioned a way of keeping _Moats_ unpassable in very cold
Countries, recorded by _Olaus Magnus_.

4, What are the ways proper to estimate the greater or lesser Coldness of
Bodies; and by what means we can measure the intensness of Cold produced by
Art, beyond that, which Nature needs to employ for the freezing of Water;
as also, in what proportion water of a moderate degree of Coldness will
{48} be made to _shrink_ by Snow and Salt, before it begin by Congelation
to _expand_ it self; and then, how to measure by the differing Weight and
Density of the same portion of Water, what change was produced in it,
betwixt the hottest time of Summer, and first glaciating degree of Cold,
and then the highest, which our Author could produce by _Art_: Where an
Inquiry is annex'd, whether the making of these kind of Tryals with the
waters of the particular Rivers and Seas, men are to sail on, may afford
any useful estimate, whether or not, and how much, ships may on those
waters be safely loaden more in Winter, than in Summer. To which is added
the way of making exact Discoveries of the differing d