components
which
then would have been
cancelled
by division).
The galvanometer differs from the tangent galvanometer only
in
its form,
insofar
as
it
uses
many
current coils instead of
a
single
coil and
partly
different
forms
of
damping.
Of
course,
the
relationship
between the
tangents
of deflection and the magnitude of
the current remains the
same.
The relative force of the deflecting
current
can
be relatively increased not only by
increasing
the number
of
coils,
but also by introducing
a
third magnetic
force that
counteracts
the terrestrial
magnetic
force and thus
partly
neutralizes
it.
The tangent
galvanometer
and galvanometer
can
be used for:
1)
detecting
currents
2) measuring currents, since they
are
proportional
to the
deflection tangents,
but
one
current and
its deflection
must be known
beforehand.
3)
measuring electromotive
forces, which is done by
passing
a
shunt current through the apparatus whose total resistance
is
known,
one
gets
then
C =
IW.
4)
measuring
resistance
by
the Wheatstone
bridge.
25.
MATURA
EXAMINATION (E)
NATURAL
HISTORY: "EVIDENCE OF
THE
EARLIER
GLACIATION OF
OUR
COUNTRY"
[21 September 1896,
7-9
A.M.]
Albert Einstein
EVIDENCE
OF THE
EARLIER GLACIATION
OF OUR COUNTRY
In order to derive conclusions about
past glaciation
on
the basis
of effects still
persisting today,
it is
necessary
to
study the
effects
of present-day
glaciers
and to
compare
them with those
remnants of earlier
times.
For that
purpose
we
have
only
to consider the effects of
glaciers
that involve rocks and
formations
because
these
are
the
only lasting
ones.
Two factors
can
be
distinguished:
the effect of the ice
itself,
and the effect of the
glacier
stream
which
is formed by the
meltwater.
The ice rubs against the walls of the glacier valley, and there
leaves behind rock
striations
in the direction of the
glacier,
i.e.,
in the direction of the
valley
floor. Of
course,
this
activity
is also
connected
with loosening
of
large
and small rock
fragments,
which fall
on
the
glacier
and build
a
landform
zone
covered by debris
along
the
edges.
firn mountain firn [Fig.]
glacier glacier
medial
moraine
lateral
moraine
If two
glaciers
unite, the
debris strips
unite
as
well and then
appear
in the middle
(medial
moraines,
as
opposed to lateral
moraines).
If,
as
is usually the
case,
several
glaciers unite, then
a
whole system of
medial
moraines arises,
and these
moraines
turn into
a
uniform
covering layer at the lowest part of the glacier
as
a consequence
of
the
melting
of the ice. The
glacier
now
melts at the bottom and
deposits this layer at the floor. If
this keeps
on
occurring at the
same
spot for
a
long
time,
a row
of hills arises
from
this
debris,
20
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