New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1862-02-04
THE CORiL REEFS.
ppor .GASsJzS THIRD LECTURE.


The Graham Institute il . bequesr Of $1,000, the
interest # which il applied, according to the oondi-
tons Of the legacy. 20 detry tie expenses OF conrse
Of leciures. every two yesrs, upon the " Vision
and Power of God ~ displayed in His Works %
The come. Of SO was BY Df. Huntington OF Hair
ward. IN ISl1 rs DIR. S,orrs OF Brooklyn, and this
wear by Prof Agassz. Tie lectures are delivered
on sunday evenings aud the third Of the present
eonrre Was attended at the Brooklyn Academy OF
Music on the I'd inst. That beautiful editce was
crowded TO its utmost capacity, and the Professor,
inspired. az he wei might be-, by the presence Of an
audience 50 Numerous and intelligent, displayed his
usal mastery on his subject 10 the best adv antage
Prof. Agassl speaks entirely without notes, desk,
or table and Is exceedingly pefspcuous IN his style.
liis lecture was Illus,rated by frequent diagrams,
which he made With chalk with admirable accuracy
and Iapidty, explaining as he does, with an ease
and s.f-vossession only attainabe BY long usage.
The rubect of the lecture was tie age oi The pres
.nt physical world az derived from ancient coins,
animal remains Of species sli extant, ana parlcu-
larry from the coral reefs Inc lecture was manly
devoted Ia the latter point IN illustration Of which
the simctasc Of the florida Keys and shore were
infinitely described. Tie popular notion that coral
. the work Of an insect was shown Ia Dc entirely err
roneos The reefs coneiet CT the organic remains of
c,sr of radiaes, similar 10 The sea anemones, but
comprising many varieties, "hi,h ne i"",s"''
Inv the different kinds of coral. The abdom-
inal cavity OF these little creatures, which Is
divided into ceeular radlations from the
center where the food Is received IL Al rst soft and
flexible but becomes rigid by the continual deposits
of ny particles until hardens INTO what Is called
coral-preseryiug not only its external shape but
the delicate cellular divisions, in the bony or she'll
like texture which chsracterizes that substance
The coras begin their work at depth OF u iahom'
never lower--and WORK upward, preterring the
seaward exposure; 40 that the coral reel II hlwayt
very steep on the outside and very gradual on the
inner shore side. The reei Ioilneu, Vi course
by the continually added adhesion OF the corsls, OF
which the finer varieties are found the req expo
sure and the baser sorts inland.
From observations made BY Prof. Agassiz az the
buiLIlnc of the Florida coast forts, and resumed IL
Years after he was enabled TO determine the rate NJ
which coral reefs grow. The Florida reels are tne
finest n the world and the best adapted to scientiii,
observations In the period Of Ia years, the growth
of coral about the foundations OF these forts Wal
found by accurate observation 10 be about one inch
which would make about seven inches In century
To be- very safe, however, nearly twice that rat
was assumed, and one foot allowed TO century
Now. IA TO the growth OF the Florida reels. Al
ontline of the peninsula was drawn, showing che
long row of islands at itr southern extremity, Gale,
the K.ys. Outside OF the Keys, and about as ta
from the KEYS "a tho Keys are from the shore, 10
second row OF smaller islands These last are found
be nothing nore nor lebs than the points OF cora
reef just emerging Their foundation is % feet be
low the surface; and taking the computation jus
assumed, this reef--the youngest on the tlorid
banks-is consequently, at least, 5000 years old
But. ON examination, the Keys are also found to D
founded upon similar reef, which, rising from "a
same depth, was formed before the outer one
This fact adds 5000 years more to the ~
Of the banks. But. landing Cd ne ,d inas'
land, the marshy hnnting-grounds walcn ;d. o'a ar
49,. sh..PA an
fond TO lie upon third reef Of precisely .imlia
character and the fact adds third 6voo years
,bs entomology Of the shore. Blu, The inyesilss,o
is not concluded; for the hnmmhcks, wnsn =. ,on,
Of the hunting grounds, are snpPor.eu jill ~
aud -till older coral reel the eXr'cnoJ durn~ ,h;c
sas .ocses.ye "ecreic1s made Positive
,rsIG cease at ibis point; but nom me s'rn
,ure Of the country further mlsno' 1t J" almost &c
,ain Thai tbe whole prouon!ory has oeV' found apN