New-York tribune., 1897-01-03

TWO RECENT CATAsTRoPHEs DUE TO
SOMEWHAT SIMILAR CAUSES.

THE cLouDsuRsr AT ST MICHAEL IN rHF
AZORES, AND THE LANpsLIps IN KILLARNEY
SOME RECENT EARTHQUAKES.
Two curious catastrophes which were reported
almost simultaneously last week from places widel,
separated appear to have been due to somewhat
similar causes. The deluge in the Azores. whereby
thousands OF human habitations were suddenly
swept away. was the result Of waterspout or a
cloudburst; whereas the landslide in Killarney
though occurring with equal abruptness. was the
sequel of more prolonged and therefore less phe-
nomenal precipitation of rainfall.
The Azores. like the neghboring archipelago the
Canaries. the product of volcanic action which
can hardly be said to have ceased entirely yet
They have hot springs. boiling mud lakes and
miniature snowstorms OF sulphur on their regular
bill Of fare. while for an occasional treat Dame
Nature gives them an earthquake that engulfs a
whole village at mouthfu. eruption that
thrusts islet out of the Just as likely
this latter piece OF generosity is quickly
GREETED. and the gift is abruptly withdrawn after a
short time. These sensational manifestations. how
ever. not equally frequent in all parts Of the
group. Fayal. for instance. enjoys rather serene
existence. while st. Michael is afflicted just often
enough to keep her inhabitants almost constantly
on the alert. When not engaged In discussing these
interesting episodes. and comparing their violence
with that of previous upheavals. the dweller in St.
Michael raises grapes. makes little wine grows
rather abstemous about navigation, however. not
having any very good harbors. The shores with
which he Is familiar usually rocky cliffs that
rise straight up out Of the water TO height OF
hundred feet more. and go straight downward
anywhere from ten to fifty times far without
stopping to take breath That sort of thing is
peculiarly convenient for love-lorn maidens who
wish TO quench their sorrows with one swift plunge;
but 1t bothers the skipper of forty-ton sloop who
seeks refuge from humming souwester SO the
skipper usually euchres the souwester by never
embarking at all. and by combining himself TO agrl-
cultural pursuits.
MOUNTAINS AND RAINFALL.
But the rock-bound coast is nothing in point Of
altitude. to the ridges and peaks in the Interior
OF course the other Azores do not rise 80 high as
Pico. which stands about 1900 feet above the sea;
and Pico is dwarf compared with Teneri1c.
in the Canary group. which has an elevation OF
1900 feet. The modest mountain range which forms
the backbone of ST. Michael seldom rises more than
900 feet. although 1t develops individual uplifts
from 1900 to $500 feet high. But this Is enough TO
exercise perceptibe influence on the rainfall. 1t
is well-established principle of meteorology that
II vapor-aden breeze encounters such barrier
the moving air mass is thrown upward, Is expanded
becomes chilled and discharges its burden OF moist
ure copiousy than il its horizontal progress
had not been interrupted. The furrowed mountain
slopes of ST. Michael are steep enough moreover.
make the streams thereon exceedingly i'm
petuous. even II temporary and intermittent.
But II was ordinary downpour that wrought
the damage just announced from that interesting
island. 1t exceptional. cataclysmal. and no
doubt belonged to that class Of phenomena known
as "cloudbursts." These, like the tornado and
waterspout, are local storms. composed of funnel
shaped cloud and rotating column Of dust or
water. The tornado belongs to the land. and the
waterspout to the Ordinarily the former Is
much more destructive than the latter. The winds
of the tornado are far more furious. But now and
then tornado. like waterspout will sustain
aloft a remarkable accumulation of condensed
moisture Whether It be merely the rotation Of the
slender air tube some other force which holds
up the watery mass 1t is not easy to say. But
Greely. Ferrel and Davis (among the best Ameri |
authorities in such matters) agree in emphasiz
ing the fact that the volume Of liquid thus borne
along Is often enormous Then, either gradually
all at once. the vortex relaxes Its grasp. and
the burden falls to the earth. Collision with
mountain side Is almost to cause a sudden
collapse Of the revolving column, and consequently
10 precipitate deluge. and II the occurrence is in
region inhabited by human beings the effects are
likely TO prove disastrous While II Is not easy to
cite individual instances 1t is probable that both
the Azores and Canaries have experienced a num- |
ber of floods in past centuries from this same |
cause; but in the extent Of the havoc wrought the
recent deluge appears TO have been without local |
precedent.
CAUSES OF LANDSLIPS.
Landslips like that which occurred last week IN |
ireland due primarily to the fact that large |
masses Of earth often rest layers Of rock which
lie santingly instead OF In a horizontal position
Friction between the adjacent and perhaps irregu-
lar surfaces goes great way toward overcoming |
the tendency of the uppermost deposit to slide along
the lower Cohesion with an adjacent mass. or |
the buttressng effect Of accumulations at the foot
of the SLOPE also serves at times to counterac the
force of gravitation. But cohesion may be impaired
by an unusual soaking: the buttresses may be re- |
moved by excavations for railroads or other en- |
gneering works. and an accumulation OF water or |
a softenng Of some intermediate pasty layer may |
reduce the friction between the two slices Of this
terrestrial sandwich
One Of the most famous Of recent landslips was |
that which occurred on the English side of the |
Straits of Dover In the night of March 49, 1s93 The
little OF Sandgate built in terrace down to
the edge of a low cliff. and reached back there
from several hundred feet. while it stretched along
the Channel for mile or more Without premo-
milton the residents discovered that their houses
shaking as IL an earthquake were in progress.
Loud rumbling attended the disturbance. Windows
burst. doors thrown out of shape walls parted
eassSs d"IS through
breakage Of the street mains There was no one
came It vas found that the. whole town had slid
s" Sut the % layer Of sand on which sandsate was
Su ~9 about 10 sars the In ssy
nothing Of barns. conservatories and other build
damage estimated at $4,000.
Long continued rains had prevailed for several
weeks Immediately previous to this occurrence, and
it believed that they rendered layer of
blue clay which intervened between the sand and |
the rock exceptionally soft and slippery. The under
mining. influence Of the waves may also have con- |
tributed to the general result At any rate, Sand
gate less fortunate than the village Of Rocca-
brunna near Nice. on the shores OF the Medi-
terranean. where some years ago a castle, a num- |
her OF more humble dwellings and lot Of orange |
and lemon groves moved considerable distance |
down the mountain side without receiving any In
jury whatever.
County Kerry. the scene of the recent disaster
In Ireland is a rugged mountainous region, with |
rich loan everything limestone rock which is not
always perfectly level. There must be a number |
OF places in that neighborhood which predis-
posed to landsdes. The soil near Baltimore was |
more less boggy, and. OF course unstable The
damming Of the adjacent river by avalanche
Of earth from the sides OF Boy Hill reminds one
- iln isanld Ia .saI.>.