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THE SEAS
order to prepare it for market this living tissue must be
removed, for it is only' the skeleton which we use.
The
fresh spohges are laid on deck and stamped upon or beaten ;
they are then strung together and hungr over the side of
the ship to macerate for a day.
They are once more taken
on deck and stamped upon, washed in tubs of sea water,
and hung up to dry.
At the end of the week they are taken
ashore and
spread on the sand to bake in the sun,
after which they are packed _up in sacks ready for sale
(Platerzô).
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SALT_Ÿ= _;_
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In many parts of the world salt is obtained from the sea.
A thin layer of sea water is allowed to evaporate in the sun
and crystals of sea salt are déposi‘ted. In orderthat this
may be a commercial propoSitio‘n it is necessary that the
summer should belong and sunny and the climate warm
and free from rain,
This manufacture of sea salt
or
“solar salt,” is therefore conned to countries like Italy,
Spain, and the coasts of California.
The sea Water'is run
into each-of a series of shallow ponds in turn.
The cry—,
_
staization of thesalts present is not uniform, and as the
density-- of the __water changes under evaporation the
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composition of the salt deposited varies. By tunning the
,
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Water through a series of evaP0ratig pools some of the
impurities are thus removed, and certain iron salts and
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calcium carbonate and sulphate have been deposited before
the :water passes intothe
in Which most of the
sodium chloride will_ crystallize… The nished product
however still contains impurities and may be __rened by
r_‘eerysta1zaüon in»fresh Water.
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Sea salt contains a certain propOrtion of calcium and
»
magnesium chlorides which are very hygroscopic- and
__
readin absorb moisture from the atmosphere. - For table
,