The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1897-03-13
CORAL REEFS.
Trying to Find out How They Are Made
But the Problem Is Still Unsolved.

An extremely interesting article in re
spect to coral reefs occurs in the LondoF
Standard, which says: A coral reef j
always delight to a naturalist but it il
also very often perplexity. 1t is vel
known that the coral polyps can only
flourish In ssa water and under certain
conditions In regard to its purity and III
temperature. To explain the origin and
development of the masses which skltt
coasts and are known as fringing reefs is
to account for the larger masses, rising
from compare lively deep water, not sell
dom several miles from land and extend
ing at times for long distances, which go
by the name of brier reefs. But tie
chief difficulty is to ascertain the origin
and development of the masses called
atollss which are more or less riHk .
shaped, though they do not Invariably
rise in all parts above the level of the
sea. This question has been for many
years subject of Keen discussion among
naturalists.
An explanation proposed rather Ii Q
than half century ago by Charles Dlsl-
win, after his return FROM the voyage Ct
the Beagle, obtained for some years very
general acceptance; but disgentients
gradually appeared, and after the return
of the Challenger, nearly 90 years ago.
the controversy was reyiyed-largey by
the writings of DR.. John Murray, VIII
had been one Of the scientific staff CT
that vessel-and ever since 1t has beeu
brisk enough. Much depended, for reas-
ons presently to be stated, upon tie
actual structure of the atoll; as to
whether it consisted OF a mass Of coral
approaching, perhaps, 1000 feet in thick
ness, OF whether 1t was mere skin, net
deeper at most than about leo feet, rest
ing upon rock of different nature.
That of course could only be settled By
boring into an atoll and examining
samples of the rock to something like tie
first named depth. Twenty or 10 years
ago this would have been a slow, ardu-
Gus, perhaps impossible task, but such
Improvements have been made in the
machinery for boring and the process
has been 80 facilitated, especially by en-
ploying the mineral called carbonado,
variety of the diamond, in arming the
drill, that there WAS good hope OF succts'
full result. This question of making the
experiment was raised before The British
association by Prof Sollas or Dublin
and after some years of discussion was
brought before the Royal society as one
to which portion of the grant annually
made to it by the government for the
furtherance of science might properly be
devoted A committee was appointed by
that body, and application was then
made to the lords of the admiralty to be
allowed the services of one of their sur
veying ships. Tbe general plan of opera
tioions had teen all eady determined; the
project had also been cord tally espoused
by men Of science in Sydney, and it had
been decided after a conference with
them, that on the whole Funauti, one of
the Ellice group, lying north of the Fiji
islands. would lie, under the existing
circumstances, the hest place for making
the attempt A favorable reply was re-
ceived from the admiralty stating that
her majesty's ship Penguin, under the
command Of Capt. Field, which was then
engaged in making surveys in the south. 1
ern seas would convey the party and
their plant for boring from Sydney to-
Funauti, render them all possible aid
during theirsstay, and meanwhile make
a thorough survey of the vicinity OF the
atnll.
OF the rival theories between which it
was hoped that experim ent would decide.
the following had attracted NEST atten-
ton. Darwin had regarded atolls as the
effects of subsistence. This was his sup
position: First, fringing reef forms
round an island, then the latter gradual
ly sinks; the coral poiyps, which 1t is
believed cannot flourish at a greater depth
than rs fathoms, keep growing upward,
but those at tae edge, being better nour
ished, increase faster than those on the
inner side of the reef, SO that gradually
it ceases to be continuous with what is
left of the island Subsistence goes on
ii II the latter has finally disappeared;
then ring-like atoll is left, which rests
on, the foundation Of an ancient frinaing
reef Thus Darwin regarded an atoll as
n monument erected by nature to the
memory of drowned island. But DR..
Murray repudiated the idea of subsistence
altogether, and proposed o very different
explanation.
We may take this hypothesis as repre-
sentative Of Darwin opponents, though
they differ considerably among them
selves. He postulated the existence of a
submarine volcano. If this did not come
polyps to grow on it's top, it was height
ened by the accumulation Of marine Or
galiisms; finally, when it came within
soundings of about $50 feet oorals began
to formI the reef. But a reef thus made
would generally be rather a small one.
SO DR.. Murray supposed that both atoll
and lagoon could be enlarged. The
former was extended in this way: The
waves broke brano hes off the outer edge
of the reef, which accumulated n talus at
it's foot, and this made foundation ON
which fresh coral could grow. But
within the lagoon the condition of the
water would be unfavorable to the life of
polyps Most of thegcoral would besdead.
This, he supposed, would be dissolved by
the; sea water and CARED away by the
tide Thus the lagoon would be enlarged
by corrosive process, and the atoll, as
a whole, would spread instheIocean like
fairy ring" in q meadow.
Both these hypothesis, and, indeed,
most of ssthe disputants, admitted that
the life of reef-building polyps was linn
tied by depth of rs, OF, at most, of 80
fathoms. Ii, then, coral ROCKS could be
pierced continuously for greater depth
than this, or, indeed. n true reef could
he struck below that limit, Darwin's ex-
PLANTATION alone was applicable 10 the
atoll. In regard to other matters, ths