sinuous
striae, stretching from one end to the other of the axis. Its texture
is extremely compact, this being precisely that which permits it to
take a perÂfect polish, and gives it a great part of its value. But
this texture is not homogeneous; on the contrary, it is perfectly
organized. To be convinced of this we have but to break or cut a branch
of coral perÂpendicularly to the axis, and to submit the part left bare
to the action of an acid. The different parts will be unequally
attacked, and a radiated texture becomes at once apparent.
Coral
exists probably in all the seas of warm and temperate regions, but the
Mediterranean furnishes .to commerce the greater part of this product.
To gather it there has been for a long time used a sort of dredge called salabre, formed
of two pieces of wood or iron, disposed in the form of a St. Andrew's
cross, upon the extremities of which nets are fastened to receive the
coral detached by the reiterated blows of the instrument.
There
are also, as in the search for pearls, divers who plunge to a
considerable depth to gather this beautiful production. But already the
modern appliances for exploring the sea-depths have been employed with
complete success to the gathering of coral.
There enters into the composition of coral 88 to 100 parts carbonate of lime, a little magnesia,
