Salinity

“ The salt of the ocean varies considerably in different parts. Near the equator, the great heat carries up a larger proportion of water by evaporation than in the more temperate regions; and thus, as salt is not removed by evaporation, the ocean in the torrid zone is salter than in the temperate or frigid zones.
The salts of the sea, and other substances contained in it, are conveyed thither by the fresh-water streams that pour into it from all the continents of the world. Maury, in his delightful work, “The Physical Geography of the Sea,” tells us that “water is Nature’s great carrier. ”

“ At Paraetonium, and on the road to Ammon, and at Casius in Egypt there are marshy lakes which are so salt that they have a crust of salt on the surface. In many other places there are springs and rivers and lakes which are necessarily rendered salt because they run through salt pits.
8. Others flow through such greasy veins of soil that they are overspread with oil when they burst out as springs: for example, at Soli, a town in Cilicia, the river named Liparis, in which swimmers or bathers get anointed merely by the water. ”

“ For instance: when we come to an arm of the sea, as the Red Sea (§ 238) , upon which it never rains, and from which the atmosphere is continually abstracting, by evaporation, fresh water from the salt, we may naturally expect to find a greater proportion of salt in the sea water that remains than we do near the mouth of some great river, as the Amazon, or in the regions of constant precipitation, or other parts where it rains more than it evaporates. ”

“ The necessary conditions for the formation of extensive salt beds include arid climate and bodies of water which are essentially enclosed—either as lakes, as lagoons, or as arms of the sea with restricted outlets,—where evaporation exceeds the contributions of fresh water from rivers, and where circulation from the sea is insufficient to dilute the water and keep it at the same composition as the sea water. ”

“ For all this, in that pure, clear water, there is a continual process of production,—not only from the soil at the bottom of the sea, but the salt-water itself contains the germs of material substances, that sustain life, or become, themselves, living things, by what appears, to our ignorant eyes, spontaneous production. ”

“ But the salt water, which has lost so much of its freshness by evaporation, becomes salter, and therefore heavier. The lighter water at the Straits can not balance the heavier water at the Isthmus, and the colder and salter, and therefore heavier water, must either run out as an under current, or it must deposit its surplus salt in the shape of crystals, and thus gradually make the bottom of the Red Sea a salt-bed, or it must abstract all the salt from the ocean to make the Red Sea brine — and we know that neither the one process nor the other is going on. ”

“ No doubt saltness is a characteristic which would naturally give a name to a river. So it does in the case of the "Salt River" in the U.S., and of the Salza in the Salzkammergut. But I can [76] hardly think that all the many rivers called the Saale are salt, and I am inclined to go deeper for the meaning. The Sansc. has sal, to move, whence salan, water. The first meaning then seems to be water—applied to the sea as the water—and then to salt as derived from the sea. So that when the Gr. άλς, the Old Norse salt, and the Gael. ”

“ In many lakes, and in the ocean, the quantity of saline matter is so great as to render it unfit for diluent purposes; but, when sea-water freezes, the saline impregnations are deposited; and the ice affords fresh water. In the state in which water is generally employed as a diluent, its impregnations are in small quantity, and not usually sufficient either to dim its transparency, or to give it color, smell, or taste, and consequently to render it unfit for the ordinary purposes of life. ”

“ More than half of them were full—full to the very bung.
But what were they full? That was the serious question. Of fresh-water? No. The appalling discovery that had been made was, that the water within them was salt! in fact, water out of the sea itself, salt as brine!
This was indeed a fearful discovery; but it was easily explained. It was known from the beginning that these butts had been filled with salt-water—to serve as ballast on the out voyage from England; and the intention had been to empty them all into the African river and substitute fresh-water instead. ”

“ The saline substances are brought down by rain, which washes the soil and percolates through the rocky ledges, and by the rivers, which are generally estimated to contain from ten to one hundred grains of salt per gallon, [3] and here probably more, owing to the abundance of soda. The evaporation is, of course, nearly pure, containing but very minute traces of salts.
It has been generally stated that the water is fatal to organic life. The fish brought down the rivers perish at once in the concentrated brine ”

“ River-water is in general purer than spring-water; as the neutral salts washed down from the earth decompose each other, except perhaps the marine salt; and the earths, with which spring-water frequently abounds, is precipitated; yet it is not improbable, that the calcareous earth dissolved in the water of many springs may contribute to our nourishment, as the water from springs, which contain earth, is said to conduce to enrich those lands, which are flooded with it, more than river water. ”

“ This is a noteworthy point, because if we assume that the presence of salt is the main factor which has prevented the land plants from spreading downwards, we are faced with the fact that the soil of the salt-marsh, where many such plants occur, may by evaporation of water become much more highly charged with salt than the sea itself. ”

“ The amount of SALT in the ocean is a circumstance which geologists have not, I think, sufficiently considered. This salt, if precipitated, would, it is believed, yield a solid range of mountains equal to that of the entire Himalaya. Now, mighty rivers run into the sea, as those of La Plata, Amazons, Mississippi, St. Lawrence, Orinoko, and many others; but none of these rivers are salt; they are enormous bodies of fresh water. How, then, does the ocean maintain everywhere its saline character unimpaired? ”

“ Doubtless, however, the chief purpose which they serve is that of removing from the sea the excess of soluble salts washed into it by the rivers, and if we call to mind that an increase in the saltness of the sea would, by diminishing the amount of evaporation from its surface, cause a corresponding diminution in the total amount of rain which falls upon the surface of the earth, we shall see that it is scarcely possible to overrate the importance of the work performed by these apparently insignificant plants. ”

“ Many ships are now regularly supplied with apparatus for distilling sea water; and on the African coasts and other unhealthy stations, where water is bad, the men of our navy drink no other water than that which is distilled from the sea.
The salts of the ocean have something to do with the creating of oceanic currents; which, in their turn, have a powerful influence on climates. They also retard evaporation to some extent, and have some effect in giving to the sea its beautiful blue colour. ”

“ We are not dependent upon neutralization for the enormous quantities of salt used in the home and in commerce. It is from the active, restless seas of the present, and from [228] the dead seas of the prehistoric past that our vast stores of salt come. The waters of the Mediterranean and of our own Great Salt Lake are led into shallow basins, where, after evaporation by the heat of the sun, they leave a residue of salt. By far the largest quantity of salt, however, comes from the seas which no longer exist, but which in far remote ages dried up and left behind them their burden of salt. ”

“ For, River-water hath the advantage of running through various sorts of Earth, by which it sucks into it self a fat, oylie, and saline Quality, which the Surface of the Earth does plentifully afford; which also is the cause of all Vegitation, and the lovely Green Colour which all Vegitables are cloth'd with, does arise from this Saline Quality. For these Reasons, River-water will Brew, Boil, and Wash, and it is more profitable in all Uses in Houswifery, than Spring or Pump-water, and far wholesomer for Men and Beasts to drink. ”

“ To the stranger looking out for characteristics, the Salt Works are the most prominent among them. The sheds stretch along like enormous stock-yards at one end of the city, but looking into them one discovers great vats and troughs filled with salt in every stage of evaporation. ”

“ Let us watch a herd startled by our approach. Away they spring, leaping into the air, turning their heads in every direction to ascertain the cause of their alarm, and then rush off at full speed; but in a short time, if they are not followed, we may see them return, especially as night draws on, and crouch down in their accustomed sleeping-places. Should a salt lake be near, they will come in vast numbers to lick up with their tongues the saline particles adhering to the surrounding stones, where the salt has crystallised from the evaporation of the water. ”

“ Each summer it is flooded with salt water when the sea is brought in by strong southwesterly monsoon winds, and the climate during the remainder of the year is hot and dry. By the evaporation of sea water the soil is thus left so salty that no vegetation can grow upon it, and in places beds of salt several feet in thickness have accumulated. Under like conditions salt beds of great thickness have been formed in the past and are now found buried among the deposits of ancient deltas. ”

“ The salt rock in the earth beneath impregnates the springs with such an intensity of brine that eighty per cent. of fresh water has to be added before the saline mixture can be medicinally employed as a bath. If you take a glass of the water as it proceeds from the spring, and put a little salt in it, the salt will not dissolve, the water is already saturated. ”

“ The cultivation of saline deserts, by washing down the saline matter, exhibits the opposite action of water in restoring fertility, and it is by no means essential that the water should contain organic, matter to insure the full effect, as the soil of deserts generally contains all the organic matter of many years’ accumulation.
An interesting inquiry naturally presents itself to the traveller while crossing this peculiar desert. By what means was the salt deposited? Two theories have been advanced by gentlemen who have visited the travesia, both to account for its presence. ”

“ From the great number of freshwater forms which we see at this present day acclimatised in, gradually acclimatising themselves in, or periodically or sporadically migrating into, the sea, we must conclude that, under certain circumstances, salt water may cease to be an impassable barrier at some period of the existence of freshwater species, and that many of them have passed from one river through salt water into another. ”

“ The customs of each tribe depend partly on which district of this large country they live in. Those who live near the salt sea eat sea-fish, and get salt by boiling the sea-water in their cooking-pots until the pot is quite dry, and then the salt is left behind after the water has gone. It was clever of those people to find out they could get salt that way. Others, who live near the great rivers, make canoes out of the tree-trunks with the inside hollowed out. ”

“ Sea-water is deficient in its proper proportion of salt at the mouths of great rivers, where the volume of fresh water displaces that which properly belongs to the sea, and therefore a river does not obtain much saline matter from that source. ”

“ I am told that the mountains are full of salt—how wonderful are the works of the Lord! In pursuit of this mineral Man has penetrated deep into the bowels of the earth by means of shafts and tunnels, and brings forth the bitter marrow of the hills into the light of the sun. The salt I have myself seen in red, brown and yellow crystals. The works give employment to our peasants and their sons, with a few foreign labourers, all under the command of an overseer, who is known as the Saltmaster. ”

“ Almost everyone is acquainted with the saltness while many bathers have noticed the superior buoyancy of salt water as compared with the fresh water of our rivers and lakes. The dissolved salts contained in sea water give it a greater density than that of pure water; and, since all floating bodies displace their own weight of the liquid in which they float, it is clear that they will not sink so far in the denser water of the sea as they would in fresh water. ”

“ Considering that the salt rivers are themselves salted by passing through salt regions, or being fed by saline springs, all of which derive their saltness from deposits laid down long ago by evaporation from earlier seas or lake basins, this explanation savours somewhat of circularity. It amounts in effect to saying that the sea is salt because of the large amount of saline matter which it holds in solution. Cheese is also a caseous preparation of milk; the duties of an archdeacon are to perform archidiaconal functions; and opium puts one to sleep because it possesses a soporific virtue. ”

“ At one time almost the whole of the salt in commerce was produced from the evaporation of sea water, and indeed salt so made still forms a staple commodity in many countries possessing a seaboard, especially those where the climate is dry and the summer of long duration. ”

“ None of the springs are very bold, but the water is strong, and sufficiently abundant for extensive works.
There have been several Salines, or mines (if we may so term them) of pure salt, discovered in different parts of the Prairies. The most northern I have heard of, is [p244] fifty or sixty miles west of the Missouri river, and thirty or forty south of the Platte, near a tributary called the Saline; where the Otoes and other Indians procure salt. It is described as resembling the salinas of New Mexico, and the quantity of salt as inexhaustible. ”