THE CORALS AS BUILDERS. 213 
by making it a law of their existence not merely that they shall 
be constantly under water which is clear and of a temperature of 
not less than 68° Fahr., but that the water shall be erated; the 
ceaseless dashing of the waves against the rocks and reefs on the 
windward side saturates them with air, as the foaming breakers 
and sparkling spray clearly indicate; and hence it is that here, © 
in the ever seething, boiling, foaming waters, these silent, unob- 
trusive and seemingly unimportant creatures, with a lineage | 
reaching back to ‘‘ chaos and old night,” are found in the great- 
est numbers, reach their highest development, and accomplish 
the best results Thus do the ocean depths below us, where by 
an alchemy far surpassing the skill and genius of man, the little 
corals secrete from the occan waves the limestone foundations for 
islands and continents that are yet to be, equally with the depths 
above where suns and systems of worlds revolve, forever reveal 
to the observing eye and inquiring mind the perfect and profound 
wisdom of their common Creator. 
We have spoken of the corals as builders, and in practical re- 
sults, such they pre-eminently are, but, as Prof. Dana has shown, ° 
they do not labor like the bird in constructing its nest or the 
beaver in making its dam, but, by a law of their nature, they se- 
crete the corallum or coral as man makes his own bones or the’ 
oyster its shell, and the vast coral formations found upon the © 
Jand and in the ocean are composed of the ania: which vey 
have left behind them. : 
No costly sarcophagus of deceased royalty—no mausoleum 
which human skill and ingenuity has ever erected—no Egyptian 
pyramid rising grandly out of the shadows of four thousand de-_ 
parted years, can even in a remote degree rival in beauty and 
sublimity the vast and varied tumuli of these little dwellers in 
tropical and semi-tropical seas. 
The corals and corallum in extensive beds abound in the Ba- 
