THE WISCONSIN FARMER.     75



where it is always ten times colder than ti
coldest day you ever saw in the coldest wintei
Well, it is there where icebergs are former
The word means ice-mountains, and is true I
the reality.
             How THEY ARE MADE.
   Icebergs are formed in various ways: somi
 times by the sliding down into the water of th
 polar seas vast accumulations of ice from th
 tops of high mountains on the coast, just a
 the glaciers we saw last summer, in the Allp
 are gradually sliding down into the valleys be
 low: there being only this difference-that th
 giaciers melt when they get down into th
 warm valleys below and run off in little streamu
 while the polar glaciers slide down into th
 cold, deep ocean of the frozen zone, and ar
 broken off almost entire.
   Again, it sometimes happens that great ic:
 cliffs, which overhang the water, as the bluff
 or rock in places overhang the Mississippi, b'
 the wearing away of the ice below, are plung
 ed into the water with a fearful splash and thez
 float away.
   And, finally, it once in a while occurs thai
the vast sheets of ice that cover the Arctic anc
Antarctic oceans is broken up into fragments,
eaoh of which is thenceforth, until melted, at
iceberg.
        WHY THEY FLOAT SOUTHWARD.
  Were there no currents in the sea, there
would, of course. be no motion of these moun-
tains of ice. But we have seen [by article in
last number] that there are such currents and
that the direction of the great polar current is
from Spitzbergen and Iceland southwesterly
towards the eastern coast of North America.
This is why the icebergs seen in the Atlantic
ocean are always floating towards the equator.
       DIFFERENT KINDS OF ICEBERos.
  In saying "different kinds,?' we simply re-
fer to extent and form. When occurring in
one vast sheet, so large that it cannot be bound-
ed by the eye, it takes the name of field; if
definable from the mast-head of a ship, it is
called a floe. Several floes crowded in togeth-
er are called a pack.
  It sometimes happens that floes in jamming



into one another force great masses up upon
the surface, so that they stand out like hills.
These elevations are known as hummocks.
           SIZE OF BONE ICEnasos.
  Fielde are not unfrequently miles in extent
and very high. Capts. Parry and Ross and
Dr. Kane, Arctic explorers, often found them
two and three hundred feet high, and so deep
that they were aground in water over a quar-
ter of a mile deep! Let us see if this could
be true: *It is found by experiment that ice
left to float in water will present one-eighth of
its thickness above the surface. If, then, you
have an iceberg the height of which above
water is three hundred feet, its whole thick-
ness must be eight times three hundred feet,
or twenty-four hundred feet. So the portion
of such a berg below Lhe surface must be two
thousand and one hundred feet, or two-fifths
of a mile!
  Can you think of anything grander than the
spectacle of a group of such monsters floating
in all their majesty out of the realms of the
frozen zone into the burning tropics ?
But they can never reach the equator. In-
deed they are never seen below the 40th paral-
.el of latitude; for as soon as they get into the
warm Gulf Stream and under the warmer sun
of the Temperate zone they rapidly melt away
tnd disappear.
     EFFECT OF ICEBERsS ON CLIMATE.
 It is strange how far the influence of even
one iceberg will extend. When crossing the
Atlantic, we felt a change in the weather when
no nearer than fifty miles. What then should
re expect of a pack, such as Dr. Kane once
got into the midst of, consisting of two hun-
[red and eighty icebergs and extending in eve-
y direction for many miles?
It has occurred sometimes that quantities of
tese ice-mountains have floated into Hudson's
Bay, and diffused very intense cold all over
De northern portion of this continent. And
,hen it is known that they are capable of so
Doling the water in which they float, as to
iake a difference of twenty degrees by the
hermometer all around them for fifty miles,
e should expect the climate on the eastern



II



I



J



I



11



I into one another force great masses up upon-11     r



I