The herald., 1897-08-22

restraint, DIS by contracting nozzle, Ol
as in the case of steam under pressure
in its closed generator, is capable of ex-
erting mechanical effort to unlimited
billions of horses power.
The transmutations of matter in the
forms of mercury and water either by
pressure or restraint, or by accretion oil
withdrawal of thermal energy are al
ways accompanied with another change
that of density-and this fact very
strongly suggests the probability thai
if We could alter the density by applying
energy to mercury or water in some form
other than that of heat, say static pres
sure of great intensity, we should CORE
spondingly produce the same several
states of both-and the accretion or ex-
pulsion of heat accordingly.
With density then appearing on the
Threshold of this disquisition as so sig
nigficant a factor in the corelatiopships
of some kinds of matter, we are led to
consider what effects are likely to be
produced in the case of matter in other
forms, wherein their several states do
not differ so widely ror in normal condi-
tions are 80 numerous, as in the in
stances of mercury and water, for exam
pie, the case of the pure metals which re-
main more or less solid through a De
cidedly varying but comparatively wide
range of temperature.
By exertinsg continued static pressure,
or momentary pressure, percussion, on
most substances they are found to be
more or less compressible, with few
exceptions, and change of pressure has
been proved to produce some change of
physical state, probably a change in
density or an atomic rearrangement of
the mass and color, too, in one substance
at least.
My friend, the late Professor James
Thomson, F. R. s.. in 1S49, as the out
come of his application of the reason
ing of Sadi Carnot, predicted that be-
cause water expands in the act of freez-
ing, the melting point of ice must be
lowered by pressure. Shortly after
wards his brother, the present Lord Kel-
win, verified this by direct experiment
and found that for each 2000 pounds of
pressure per square inch the melting
point of ice is lowered one degree cent?
grade. From this eXperimeDtally prov
ed fact we deduce that as the pressure
tended to prevent change of density
or atomic rearrangement in the ice, 50
it could not so readily undergo the mo-
lecular change of contraction which the
matter of water does undergo in its
tran sformatio from the solid into the
LIQUID state Whence, too, the further
Inference, that if the water is enclosed
in strong enough vessel and under d
static pressure great enough to insure
lo oy,1a al Is 70
sci, 80 that 1t cannot be expanded by n
change in its molecular condition by
being lowered in temperature to the
freezing point of water, then just as it
cannot in such restrained condition be
expanded, so cannot its density be re-
duced, and therefore by just SO much
can water so enclosed under like pres
sure not be frozen. Prima facie it would
appear that in all probability such an
experiment could, not be made with wa
ter, when we reason from Bacon's eX
periments with water contained in a
closed lead sphere or upon the expert
ments of the Academic del Cimento at
Florence of about fifty years later, when
similar test was made, but with a
sphere of silver instead. of a sphere of
lead.
In both cases it was found (Bacon
using percussion and the academy static
pressure) that the particles of water
oozed through the pores of the metal.
The same thipg is found today in the
case of the thick cylinders of hydraulic
rams.
Suppose we did enclose water in an
ever, so thick vessel of denser and hard
er metal say of steel, and applied suf-
ficient pressure, it is probable that this
oozing might not occur, and that on SUBJ
mitting the thick vessel containing tha
water under pressure to the low temper
ature now obtainabl with the apparat- =
us designed. by Professor Dewar, and
bearing in mind the enormous rendins
power of water by its expansion or con-
version into ice, it is probable that no
material exists which would Withstand
the concentration of energy tending to
rupture the closed vessel containing the
water 80 soon as the temperature is low
enough. BY the expapsior' of water in
freezing it is known that some of the
loftiest Swiss mountains are shivered
and riven from top to bottom. This is
notably the case with the Matterhorn
as Tyndall pointed out. Boussingault
has, however, made a closely analogous
experiment OF which I did not kpow
when writing the foregoing. quote the
account of this from the fascinating
work of Tyndall entitled, THE Forms OF
Water in Clouds and Rivers, Ice and
Glaciers" Am. edition, PIP. 40, III
Another beautiful experiment bear
ipg upon this point has been made by NJ
Boussingault. He filed hollow stee
cylinder with water and chilledit.
The strong cylinder resisted the expan-
sion, the water in consequence remained
| liquid. at temperature of more than 81
| degrees Fair. below the freezing point
A bullet within the cylinder rattleC
about at this temperature, showing tha
the water was still liquid. On opening
the top the liquid, relieved of the pres
sure, was instantly converted into ice. ;
The same fact in respect to pressure AMI
density was proved by very ingeniou!
experiment, devised and, carried out by
j. I. Bottomley, in the physical labora
| tory of the Glasgow university, by con
centrating pressure upon a small SIR
face of ice in the following manner
Bottomley took rectangular prism o
ice ten inches long, four inches deep ant
three inches wide. This he supported
upon two blocks of wood, and over tn
center OF the prism thus supported, a
| bridge, he placed a loop of small coppe
| wire. Connecting the two ends of tn
| wire fopether he sIISne r6.ad fro,, ~