o make the Trials with _Mediums_ of two great
thickness: where it is made to appear, that Cold is able to operate through
Metalline Vessels, which is confirmed by a very pretty Experiment of making
_Icy Cups_ to drink in, whereof the way is accurately set down. Then are
related the Trials, whether, or how, Cold will be diffused through a
_Medium_, that _some_ would think a _Vacuum_, and which to _others_ would
seem much less disposed to assist the diffusion of Cold, than Common Air it
self. After which follows a curious Experiment, shewing whether a Cold Body
can operate through {51} a _Medium_ actually hot, and having its heat
continually renewed by a fountain of heat.

12, How to estimate the solidity of the Body of Ice, or how strong is the
mutual adhesion of its parts? and whether differing Degrees of Cold may not
vary the Degree of the compactness of Ice. And our Author having proceeded
as far as he was able towards the bringing the strength of Ice to some
Estimate by several experiments, he communicateth the information, he could
get about this matter among the Descriptions that are given us of cold
Regions: and then he relateth out of Sea-mens _Journals_, their
Observations touching the insipidness of resolved Ice made of Sea-water;
and the prodigious bigness of it, extending even to the height of two
hundred and forty Foot above water, and the length of above eight Leagues.
To which he adds some promiscuous, but very notable Observations concerning
Ice, not so readily reducible to the foregoing Heads: _videlicet_, Of the
blew colour of Rocky pieces of Ice; and the horrid noise made by the
breaking of Ice, like that of Thunder and Earthquakes, together with a
Consideration of the cause, whence those loud Ruptures may proceed.

13, How Ice and Snow may be made to last long; and what Liquor dissolves
Ice sooner than others, and in what proportion of quickness the Solutions
in the several Liquors are made, where occasion is offered to the Author,
to examine, whether Motion will impart a heat to Ice? After which he
relates an Experiment of _Heating_ a _Cold_ Liquor with Ice, made by
himself in the presence of a great and Learned Nobleman, and his Lady, who
found the Glass wherein the Liquor was, so hot that they could not endure
to hold it in their Hands. Next it is examined, whether the effects of Cold
do continually depend upon the actual presence and influence of the
manifest Efficient causes, as the Light of the A