Evening star. [volume] (Washington, D.C.) 1854-1972, 1913-07-19

A
The greatest distance we observed Ice
was eighteen miles. The day was clear,
with light easterly winds and q tendency
to mirage. It seemed to suddenly jump
into view and could be plainly seen from
the bridge as soon as from the crows
nest On ordinary clear days the average
berg can be seen twelve or fifteen miles
from the bridge, about mile farther
from the crows nest, and a mile still
| farther from the signal yard. On cloudy
day with good visibility deduct about
two miles from the foregoing. In clear
| weather with hazy horizon we have seer
| q big berg IL miles, its top being visible
well above the horizon; In light fog,
miles: dense fog, 200 yards; drizzling rain
! 21a miles. In bright moonlight, with
naked eye. 21a miles: moon shining
through thin nackerel clouds. 2 miles
starlight, / mile, with naked eye, . miles
with glasses; overcast and dark. but with
horizon visible. Il mile with glasses. In
the last case the berg looms up dark: in
the other cases its effulgence shows light
er than the surrounding space. With the
searchlight we were able to see a berg
about three miles on dimly moonlight
night and two miles after the moon set
Using the Searchlight.
I'm using the searchlight We found
that an observer standing behind or un-
der the beam could see practically moth
ing, but that fifteen feet away to one side
he could see readily. With the beam
turned on berg abreast the ship and
two miles away. i could see it as plainly
as an illuminated store front from the
quarterback. about 100 feet abaft the
light Another point to be noted is that
the beam must be drawn to fine focus.
flaring beam blinds the observer Ow-
ing to the binding effect of a searchlight
on the observer. / should not recommend
Its general use for a vessel under way.
[<,.l ,,xvl@ til
vessel in the vicinity of bergs should slow
so as to be able to maneuver within the
limit of visibility.
"A berg may or may not give an echo.
IL Its sides are steep or perpendicular an
echo will probably be heard from some
directions. but not from others. accord
ing as the face presented to the ship is
normal or slanting. Any slanting face
will reflect sound away. We were not
successful in getting echo farther than
half mile.
About 80 per cent of our attempts
were without result. The existence of
an echo indicates an obstruction, but its
absence proves nothing. In one case we
were between a berg and growler; the
GROWER gave an echo. but the berg
none.
Sudden changes of temperature mean
nothing, so far as bergs are concerned.
The sea water is streaky as a rule and
where its temperature is constant we
found no change up to a ships length of
berg. The coolest water we found was
81 degrees, on the tail of the bank in
April, about 100 miles from the nearest
ice. Surface temperatures are about =
degrees higher than the injection. Close
to a berg the water at surface falls from
. to degrees. With maximum and
minimum thermometer we found no
change from temperature of injection
down as far as twenty fathOms. Al
thirty fathoms the pressure broke the
bulb of the thermometer.
Detecting a Berg.
I'm light, low fog an observer can
see a berg from aloft sooner than from
deck. but in a dense fog we found that
the lookout was best kept from the spar
deck, as the first sight Of the berg was
the tapping Of the water on its base.
Speaking about lookouts, it occurs to
me that on a very large ship. with decks
some twenty feet higher and lookout
posted higher up still. the lookout might
well be higher than the top of q small
berg, and hence on a dark night he would
have an unobstructed view Of the horizon
over a berg half a mile or a mile away.
In that case he might easily miss seeing
the obstruction until too late to avoid it.
las rule we found little or no change
in temperature of the air near berg.
THE presence of GROWERS or small
49,
ward.
The roar Of breakers on a berg and the
rumbling of breaking ice can be heard as
far as mile on calm day. =.
so far as our observations went, the
bergs drifted with the surface currents.
Where two currents meet, the dominant
one eventually takes charge.
DIsfnregratIon OF Bergs.
"Disintegration of bergs takes place
| slowly in water of "a degrees or below
At SO degrees melting and erosion are
quite noticeable, and at 90 degrees the
changes can be noticed from hour tc
hour. We had under observation for sew.
eral days two bergs as they approached
the gulf stream. Both turned over the
day they entered the warm water. show
ing that melting of the underwater body
was going on more rapidly than above
] estimated the daily diminution at 5 pei
! cent in water of temperature so degrees
Melting above water is going on slowly
all the time, the water trickling down the
declivitieS in small streams.
'One large berg had a small waterfall
on one side under which II would have
been practicable to hold a boat for the
purpose of watering ship. The tempera
ture of the air was As degrees. As l have
stated in a previous report, erosion take.
place by water dashing up on slantins
| sides of bergs and by scoring out th'
| water line of steep sides. In the frs
| case the ice is dsintegrated by sloughins
| and in the second. by calving. Large ifs
! sures may be seen at times in the sides O
bergs. and as these increase in size grea
| chunks are likely to fall Off in the form
| of GROWERS.
AT the rate OF 5 per cent disintegratiol
| a day a berg would last only abou
| twenty days in the gulf stream, but tn,
| larger the berg the slower it seems t
| melt, and 1 have no doubt some of tn,
| largest would last two months
Observations of the natural history OF
| the waters over which he Travelled are
described as follows:
LAS to birds. make little claim to ex
] pert knowledge of ORTHODOXY, but to the
| best of my Judgment these are all the
| birds we have seen in the ice regions
One putin and three mallard ducks, fly
/ ing and not near any berg; hagdon gull:
| in large numbers sirgly and in flocks
/ some around bergs. but more likely Il
be near some fishing vessel; arctic full
! mar, plentiful. singly or in small s1ocks
| cruising about everywhere, irrespective
| of bergs; petrol. TWO varieties in small
numbers. following ships or resting OF
/ bergs; Jaeger, few, usually near some