New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1914-02-15
Abbott Thayer Tells Why
IcebergS Are Invisi-
bic at Night.
A STEALTHY PERIL
HALF DEFIED
How Shipping May Be Protected
by Attention to a Simple
Matter Of Vision.
To the Editor Of The Tribcne.


Sir: How many more years are we to
lave Of CHANGING u ~ sea, as 10 another
Titanic disaster. before the world realizes
its doathly error i'm the universal notion
that .cobergs AZ night are visible because
they are ichucg Il is precisely when they
ere purest white that they are at night In
visible (and white is OF course. their
typical color. although they sometimes
carry earth staiusb. u should be the duty
Of Tie governments summer iceberg pa
troll steamers 20 lie to By icebergs and
discover this terrible fact. one observa-
ton Of this phenomenon published by
them would convince the world that what
is now supposed to be an artists visionary
Theory Is a fact-a fact that. spread at
once through all marine channels. would
instantly revoutionize the handling OF
shipping in the vicinity of ice
The snowy roofs that stand all about
tine homes Of your readers in the country
furnish them. II they only realized it. the
whole truth as To- how visible is the aver
age iceberg at night And any one who
wishes 10 help destroy an error which is
a frightful menace 20 the lives OF those
who go 10 sea has only TO notice these
roofs and tell what he notices. BY day
and by night their absolutely white sur
faces have the exact color Of similarly
situated clouds ana Of icebergs. The
clouds material is Of exactly the same
pure white. and so is the disintegrated
ice Of the average berg. All three OF
these substances. cloud. snow and the dis
Of If
same snowy white, and under external
illumination are practically identical in
color.
Anywhere in the country. away from
artificial lights $50 far away that the
whole sky is unaffected by them). look at
your snowy roofs at night, especially In
a clear starry night lathoush both
cloudy and also moonlight nights have
each their especial power TO work SINH
lar effect. and as often as YOU find one
totally indistinguishable say 10 yourself
Just so fatally invisible would that white
surface be il il were the roof of an ice
berg and l the officer on the bridge and
three thousand human lives In that ship
within thirty seconds Of another Titanic
disaster"
You will soon learn that, in fact such
roof. and therefore such berg, never
at night ranges into greater visibility than
TO resemble a cloud. so that practically no
white berg is recognizable at all at night
until YOU are absolutely upon it, because
its TOP outline is sure to be wholly miss
ing. and all that remains resembles at
most fog bank The only exceptions
would he either a berg that jutted for
ward clear up to a knife-edge top-pre-
senting so darkly Swallowed a side, clear
10 10 its top edge as 10 show a dark sill
houetto-or else a berg in some angles OF
moonlight. All this shows why the Ar
Zona'c watch. years ago, could not see the
berg they struck. and why the same thing
happened to the Titanic. CFor scientific
accuracy it must be stated that clouds
inferior density limits, a very little its
light-and-shade range. as compared to
that Of snow. or the exactly snow-colored
disinteCrated ice Of the tops Of berss).
If any one wishes to learn how hopeless
" far from detection such a white surface
Is out under the night sky let him study
such roofs i'm broad daylight whenever
the daylight is uniform. as 1t averages on
a
Of the time. even in this daylight illumina-
ton. either quite indistinguishable or very
near IT, Now. the brightest starry night
is only about one. three or four thou
sandths Of the brightness Of daylight. and
differences already hard TO detect by day
are just so many thousand times further
from detection al night. Shut off gradu-
ally the illumination Of your room, ana
one by one its fainter details viii be-
come indstinguishable. while the objects
that present the strongest contrasts of
light and dark will be the last to disap-
pear.
The watch on the ship is Hochore near
being able 10 detect such a berg, and 60
ing ahead at all at night where there are
signs of ice is pure crime.
When announced all this in THE
Boston Post all | got for il was their
quoting a brilliant minded sea captain,
who said that he had been long at sea.
but had never seen at night berg that
was the color Of the sky In other words,
he had never seen an invisible iceberg. To
Judge by his name. if I remember It, he
was not Irish. either Theodore Roosevelt.
too. is doing his utmost TO keep alive this
fatal error. about supposed intrinsic
tower Of white TO be always conspicuous.
In this case. where thousands OF lives are
menaced. his habitual cocksureness is
grave matter in view OF his extraordinary
mower 10 influence others Colonel Roose-
Welt. speaking of my writing that
sllnIfs white top and forehead match the
sky and become. Of course. invisible when
seen against 1t by small animals that look
I'd at il from the turf, puts himself down
as totally unable to grasp an optical prlh-
ciple or perceive that there can be no sRch
,hing os INTRINSIC conspicHorSneSS'
since things show or don't show wholly
according to whether you look AT thsh
against n contrasting background or one
that they match. The THAMES survivors
in the nfeboats saw 1.-THE dark form OF the
ship outlined in black against the SKY
1.-TWO miles on. while they saw none OF
the white berss against whose feet they
actually heard the wash OF the sea.
4 black thing shows against the Hght
and a white one shows against the dark
and there IS the whole thing. Try 70
make n white mark on white paper or
black mark on black. Roosevelt says o,
me: "IIe explicitly states that skunks
are nocturnal. and il does seem incred-
/ ibe that he should believe that white Is
inconspicuous at night This is one OF the
elementary facts as to which ii is impos-
sible to argue. 1t is only possible to state