The Portland daily press., 1897-02-11
FACTS FROM AN OLD MAP
Remarkable Showing of Topographic
Changes in Two Centuries.

Changes in Two Centuries.
1t is we'll known that our Appalachian
than tbs Rocky Mountains of today and
that the reason why they are nowcom-
paratively low mountains is simply Tat
they are very old and have been worn
down by denuaasion. The same defruc-
tive influences are still degrading item,
very slowly as we measure ordinarytime
to lower levels. We know that chlnges
are constantly going on in the physical
condition of the earth's crust, but ihese
changes are SO slowly accomplished thai
they can scarcely be observed, In many
cases. in an ordinary lifetime. In the
coming ages students of physioglaphy
will have great adv antage over th'ss OF
today; for the art of accurately delneat-
ing the surface of the earth by means Of
contoursd maps is "a comparatively re-
cent invention. Hundreds Of yearsfrom
now the photographers Will be aide to
learn from the maps We are making now
exactly what the surface features OF large
areas were in our time, and it will be
easy to make instructive comparisons
with the same features rs they find them
Professor Edward Bruokner has recent
| IL described in Pstsrmann' S MitteiltnRsn
the very interesting results OF COMPARE
tive study of remarkable map o. the
seventeenth century and one of the Swiss
survey MAPS of today. In 1857 Mr.. j. G..
Gyger completed his map of part Of the
Alpine region extending from the Rhine
on the north to the Reuss on the south
| ana including phe whole of the canton OF
| Zurich, in switzerland. The map was on
on unusually large scale for that time,
| TIE scale was 1872, 900, or one inch on the
map for about half mile in nature H.
worked compass in hand, paced his dis
tances, and was verysscareful and hbor1-
GUS in his survey. He gave great deal
of time for thirty-seyen years to his map.
| He was the hrst TO use lights and
shadows to indicate and contrast noun
tain slopes Two copies. of ibis map, both
signed by him, are extant, and they still
excite tie admiration OF cartographers
| for tie wonerfa1 accuracy with which
they depict topography. Until thii cen
tury the Gyger map was regarded a. the
hest photographic delineation OF the
Zurich canton. Small parts Of lit have
been published with corresponding Sec
tious of the present surveys to show the
high standard Of accuracy Mr.. GyRer at
| tanned.
Mr. II. Walser has carried out. in the
! q Geographical Institute of the Univeriity
of Bernie. the comparison between the
Gyqer map and that Of the present day.
| Mr. Gyger carefully showed, every lase.
large and small, in the canton, and
sharply distinguished the lakes from the
swanps. His map showed 149 lakes III
| the canton. OF these no less than seventy
three are not found on the present maps.
These lakes. as Mr.. Walser points ont,
one by one have become extinct. They
were all small, most of thsm having an
area of less than twenty-five acrsg. The
area of sixteen other lakes is now much
reduced, and twenty others are some
what smaller than In the seventeenth
centur Forty lakes have undergone no
| important change.
! Mr.. Walser has ascertained by obseYva-
tfop the causes of the shrinkaRe sor dis
appearance of Fifty -four OF these lakes.
| This farmers in their efforts ito secure
more meadow land, have played An i'm
portant role. They have drained quite a
mum her of the lakes and turned their
| beds into hay farms or pastur lands.
| OF course, in geological time, all lakes
are drained by the natural cutting down
| of their OIL tlets, but, on acco unit OF the
unimportant slope OF tbs outlet channels
of there particular lakes, the deepening
of the channels WAS very slow. and this
| form of lake placement seems to have
cut no figure.
Tbe effects Of two other natural causes,
however. are very evident. One was the
filing up of the lakes by the deposit OF
sediment, and the other. and more i'm
| portant, the gradual encroaohment OF
pia7:t life in the lakes, which finally
completely filed them, the dscny Of
yegitation forming soil, and thus the
lakes were gradually extinguished. Some
of t:e lakes are still undergoing thii
nrocees. the carpet of plants extending
all around the shores. while little water
surface is still visible in the center. Ths
| doposition of sediment and the growth OF
plants which finally obliterhtsd these
! little lakes were. OF course, supple
mentsd. as Mr.. Walser says, bv the
human activities that, in the past cen
| tury. largely cut off the water supply
| that NJ ade and fed them,
Mr.. Gyger very carefully showed the
| forests on his map, and the comparison
that has now been made between tho ares
uf forests in the canton two centuries age
| and at the present dag is very iRteIesiEa
| in view of the statement, often heard
| that Europe Is gradually unoeIRolHB uo
| forestation. Proof is afforded that, al
lenst in this district, the forests have jus.
about held their own. Two hundred ane
| forty years ago, according to the GyRel
man. there were 1872, 500 acres of forests II
the Zurich canton. There are now 12O, O0l
acres of woodlands, or, in other words
the forest nrea has been depleted onlI
about tan per cent sincs Mr.. Gygsr mad'
his map. The sleeper slopes are sill
wooded as they were except here ane
| there whore woods have given place t.
vineyards. The forests have increased OF
the food plains of the rivers, ami also OF
the hill slopes near the Rhine: they hav'
held their own in the northwest part
and In the region of the Lower Toss
while the wooded area has been reduced
a fourth in the iona district.
MIR. Gyger also delineated on his NAL
the areas given to wine cultule. fYon
which it appears that the increase In th'
amount Of land devoted to this iDdustr!
at the present tins Is about rs per cont
Asa rule wine culture is not ATTEMPTED
new on shaded slopes and at high alti
tude to 40 great an extent as 1t was wv
centuries ago.
A very noteworthy recession of the Lax
area very little change in the extent o
the forests. and an important increase II