m 
with water, and expefed to the cold Air, do burft 5 and where 
aifo the weight is exprefled, that will be removed by the expan* 
five force of Freezing? Wherennto an Inquiry is fubjoined, 
whence the prodigious force, obferved in water, expanded by 
Glaciation, fhould proceed ? And whether this Phenomenon 
may be folved , either by the Cartefian , or Epicurean Hypo- 
thefis ? 
11, What is the Sphere of ABivity of Cold, or the Space, to- 
whofe extremities every way the Atftion of a cold Body is able 
to reach : where the difficulty of determining thefe limits, to- 
gether with the eaufes thereof, being with much circumfpcfti- 
on mentioned, it is obferved, that the Sphere of ABivity of 
Cold is exceeding narrow, not onely in comparifon of that of 
Heat in Fire, but in comparifon of, as it were, the Atmofphere 
©f many odorous Bodies ; and even in comparifon of the 
Sphere of ABivity of the more vigorous Loadftones , infomuch, 
that the Author hath doubted, whether the Senfe could difcern 
a Cold Body, otherwife then by immediate Contract. Where 
feveral Experiments are delivered for the examining of this 
, matter, together with a curious relation of the way ufed in Per - 
fia, though a very hot Climate, to fnrnifh their Confervatories 
with folid pieces of Ice of a confiderable thicknefs : To which 
is added an Obfervation, how far in Earth and Water the Froft 
will pierce downwards, and upon what accounts the deepnefs 
of the Froft may vary . After which, the care is inculcated, 
that mu ft be had, in examining, whether Cold may be diffufed 
through all Mediums indefinitly, not to make the Trials with 
Mediums of two great thicknefs : where it is made to appear, 
that Cold is able to operate through Metalline Veffels, which is 
confirmed by a very pretty Experiment of making Icy Cups to 
drink in ; whereof the way is accurately fet down. Then are re- 
lated the Trials, whether, or how. Cold will be diffufed through 
a Medium , that fume would think a Vacuum , and which to others 
would feem much lefs difpofed to affift the diffufion of Cold , 
than Common Air it felf. After which follows a curious Ex- 
periment, fhewing whether a Cold Body can operate through 
a 
