66 
POPULAR SCIElsTCE NEWS. 
[May, 1891. 
The recent or quarternary period includes the 
various superficial deposits in which all the mol- 
lusca are of still living species. It is usually sub- 
divided into two series : (1.) Tlie older group of 
deposits in which many of the mammals are of ex- 
tinct species. To tliis group the name Post Plio- 
cene or Diluvial has been given. (2.) A later 
series, wherein the mammals are of still living 
species, to wliich the name Recent or Alluvial 
has been given. These sub-divisions are, how- 
ever, confessedly very artificial, and it is often ex- 
ceedingly diflicult to draw a line between them 
with exactness. 
In Xorth America and Europe a tolerably sharp 
demarcation can usually be made between the 
Pliocene formation and those to be described as 
mentioned above. The crag deposits of the soutli- 
east part of England show traces of a gradual 
lowering of temperature during the late Pliocene 
times. This change of climate continued until 
thoroughly Arctic conditions prevailed, under 
which the oldest of the Post Pliocene deposits 
had accumulated. 
■ ♦♦» 
[American Journal of Science. J 
EFFECTS OF PRESSURE ON ICE. 
Bt K. W. WOOD, Jll. 
Certain theories regarding the movements of 
the great glaciers of the ice epoch, depending on 
the pressure-melting of ice, a number of experi- 
ments were performed by the writer, to determine 
the eftect of great pressures on ice masses at 
various temperatures. The experiments were 
tried with a hydrostatic press capable of yielding 
a pressure of one hundred tons on its 6^ inch 
ram, the first one l)eing made to determine at what 
pressure ice could be made to flow through a tube 
of small diameter. 
A block of iron was cast measuring 6X4X4 
inches, and drilled to the depth of four inches 
with a 1% inch hole, to which was fitted a solid 
steel piston, turned with such accuracy that, 
when oiled, it worked air-tight except under con- 
siderable pressure, when a few bubbles oozed 
through. Into the side of the block a l-12th inch 
hole was drilled, which communicated with the 
bottom of the cylindrical cavity precisely like the 
vent of a cannon. The cavity was nearly filled 
with ice at the melting point, and the steel piston 
inserted. The apparatus was then put under 
pressure ; for a minute or two water flowed from 
the hole, with occasional air bubbles which effer- 
vesced with a white foam on emerging. The index 
of the guage showed that the ram was exerting a 
pressure of about six tons ( three tons to the inch, 
the piston being two square inches in cross sec- 
tion) when the ice began to rise through the small 
hole. It rose slowly and steadily at first, as a 
cylinder of clear ice, which broke oft" when six or 
eight inches in height, then faster as the pressure 
increased, until the guage indicated a pressure of 
nine tons, when it seemed fairly to spurt from the 
orifice, pieces two or three inches long being pro- 
jected to a height of a foot or more into the air. 
It flowed with an irregular motion, which did not 
correspond with the strokes of the pump, but 
seemed to indicate that the ice was in a viscous 
condition, seeming to stick for a second or two 
and then yield suddenly. On reversing the presg, 
and removing the piston, what was left of the ice 
was found moulded into a clear transparent block. 
The next experiment was to test at what 
pressure ice at the melting point would become 
fluid as a mass. An iron block similar to the one 
used in the previous experiment, except that it 
was without the small hole, was filled with ice in 
which were imbedded several small bullets, the 
positions of which were carefully noted. The 
piston was fitted and the mass subjected to pres- 
sure. The index showed a tension of fourteen 
tons, above which point it was difficult to force it, 
since the ice melted rapidly, and the water oozed 
out around the piston in spite of its perfect fit. 
On releasing the apparatus and removing the 
piston, the bullets were found in the same posi- 
tion ; they had not dropped to the bottom of the 
cavity as they would have done had the mass been 
reduced to a liquid state, thus proving that under 
a pressure of seven tons to the inch ( 933 atmos- 
pheres) the ice had remained solid or viscous to 
such an extent that it could easily support the 
lead. 
These same experiments were repeated under 
conditions of greater cold : the blocks, after being 
filled with ice, were exposed to a temperature of 
about — 5° Centigrade until thoroughly chilled, 
and were then carried to the press. This obviated 
the difficulty of the rapid melting caused by the 
heat of the iron. The results obtained, though 
practically the same, were more marked than in 
the first experiments. The ice cylinders came out 
with more violence than before, some fragments 
being projected to a height of ten or fifteen feet 
into the air. They were of clear, transparent ice, 
and several inches in length. Small jets of water, 
in finely divided spray occasionally spurted out 
around the ice cylinders as they rose from the 
tube; this spray congealed on falling back upon 
the block, showing that the iron was below the 
freezing point. 
ITie experiment with the bullets was repeated 
with the apparatus chilled below 0° C. A pressure 
of twenty-four tons was reached before the index 
of the guage stopped ; water spurted out in a 
spray around the piston, and instantly froze on 
the surface of the block as it ran down; ice, too, 
oozed out in thin sheets. On removing the appa- 
ratus it was found that the bullets had not 
dropped, showing that a pressure of twelve tons 
to the inch was insufficient to reduce the ice to a 
liquid state. One bullet which lay close to the 
wall of the cylinder had been ground bet^^•een the 
piston and the wall, and a portion of it was spread 
out in a thin film over the iron. As a final test, a 
piece of oiled leather was inserted between the 
piston and the ice, which ett'ectually prevented all. 
leakage. The index hand moved slowly along 
until it reached a point indicating forty tons, 
when suddenly the air was filled with fine jets of 
spriiy which spurted in ali directions from the 
block. The water had actually permeated the iron, 
forcing its way through the pores of the metal or 
breaking minute paths for its exit, and emerged 
in covintless jets from the surface. 
This of course put a stop to fui'ther experiments, 
the limit of resistance of the iron having been 
reached. A calculation will show that in the last 
experiment the pressure was sufficient to liquefy 
exactly one-fourth of the ice, being that producetl 
by a column of ice twenty miles high. Even under 
this enormous pressure the ice was found to have 
had sufficient viscosity to support the weiglit of 
the shot. 
The maximum depth of the ice in the glacial 
epoch never exceeded two miles, and such a mass 
would yield a pressure of about two tons to the 
inch, or two hundred and sixty-six ( 266 ) atmos- 
pheres. Sir William Tiiomson's experiments show- 
that the melting point of ice is lowered .0075° C. 
for every atmosphere of pressure-, that is to say, a 
mass of ice subjected to pressure has its tempera- 
ture lowered .0075° C. for every additional fifteen 
pounds to the inch. Let us now consider exactly 
what the eftect of a pressure of 266 atmospheres 
will be ; the reduction of temperatue will of course 
be .0075° X 266, or — two degrees Centigr.ade (more 
exactly 1.955° C). Starting with water at 0° we 
shall then have a mass of ice and water at a 
temperature of — two degrees Centigrade. To 
determine the amount of ice melted or reduced to 
a state of pressure-molten water, we make use of 
the well-known formula, 
temperature (in — degrees) 
79.25 
X being a fractional quantity representing the 
proportion of ice liquefied, and the constant quan- 
tity 79.25 being the latent heat of fusion for ice. 
The result is 1-40, this being the exact amount 
of ice that will be liquefied by a pressure of 266 
atmospheres. The condition of a lower layer of a 
mass of ice two miles thick will be as follows : 
The temperature will be — 2° Centigrade, and a 
certain portion, namely 1-40, will be in the state 
of pressure-molten water, which, being diffused 
through the mass of the ice, will not sensibly 
diminish its rigidity. 
It will be seen that the pressure of such a mass 
of ice was considerably less than that required to 
cause ice at the melting point to flow easily and 
rapidly through a small orifice. It may be argued 
that the time element has not been considered. 
Time has nothing to do with the result, except as 
heat is fed to the bottom layer from the earth. 
Insulate the mass from all sources of heat, and 
the equilibrium will remain unchanged until the 
end of time. The law of conservation of energy 
decrees that this must be so. 
It is true that glacial ice was not thus insulated ; 
that it received heat from the earth we all admit, 
but let us consider exactly what the effect of this 
heat supply was. We have at the beginning a 
temperature of ^2° C, and one-fortieth of the ice 
in a liquid state. Heat is fed from the earth, which 
tends to raise the temperature, but the constant 
pressure keeps this uniform, and the heat is 
expended in melting more ice. After a lapse of 
time we shall have a considerable portion of the 
ice in a liquid state, but by considering carefully 
the conditions, we shall see that it Is thermo- 
molten and not pressure-molten. The temperature 
remaining^onstant, as it is bound to do under ;i 
constant pressure, we shall have a mass of water 
at — 2° C. underlying a mass of ice of enormous 
weight. This water has not the properties neces- 
sary to prevent its escaping from beneath the ice, 
for it the pressure be relieved at a crack or break, 
only 1-40 of the mass will congeal, which will 
scarcely be sufficient to seal the means of escape. 
In other words, as fast as water formed beneath 
the glacier, it would be squeezed out by the pres- 
sure of the ice. The results of these experiments 
appear to render tiuestionable any theory account- 
ing for peculiar motions of glacial ice by supposing 
the existence of a layer of pressure-molten water 
beneath the mass. 
[Original In PoPHi^R Science Hews.] 
A WONDERFUL ARTIST. 
BY ANNA HINRICHS. 
The fluent autograph of Adam Siepen, here 
reproduced, is far from suggestive of tlie curious 
fact that it is a specimen, not of hand but of foot 
writing. This at once awakens interest, which 
intensifies with the knowledge that the writer of 
the original is an artist of renown, whose artistic 
creations are the work of his feH. 
Adam Siepen is the son of a well-to-<lo fanner in 
Dflren, Germany. In 1851, he was ushered into 
