A Grain Of Table Salt

The salt in the kitchen or on the dining room table seems a very common place thing. Yet, in each grain of salt there lies a story full of romance and wonder, a story which few of us know.

Many millions of years ago much of the world's present land surface lay under vast salt seas. Gradually the water of these seas dried up and left their salt behind them. During the ages that followed, the salt of the ancient seas became buried under many feet of earth, clay, and rock. Today a large part of the world's table salt supply comes from the great veins or beds of almost pure salt formed by this burying process.

The other great source of salt is the water from salt springs, salt lakes, or, still more important, the seas. The Dead Sea, in Palestine, and Great Salt Lake, Utah, are so saturated with salt that one cannot sink in the water. The Dead Sea is so salty that no life can exist in it.

Since the earliest times, man has been conscious of the necessity for salt in his daily life as an article of food. All human tissue requires salt, and blood can be replaced to a certain extent by a solution of common salt. Salt helps in making hydrochloric acid, which helps us to digest our food.

An animal or a man with insufficient salt in his food will grow feeble, and with no salt at all may die. Yet at the same time, too much salt in your diet can cause serious health issues too. Wild animals instinctively seek out salt pools or salt rock "salt lick," often traveling great distances to reach them. Man too, has gone great distances and undergone much hardship to secure a bountiful supply of it.

The Phoenicians, the great traders of the early world, established a regular commerce in salt. Salt from the great mines of India was carried to Mediterranean markets by camel caravans more than two thousand years ago. Some of the caravans routes of today originated as salt roads ages ago, long before they were silk roads.

The Via Salaria, which means Salt Road in Latin, is an Italian road which was used in ancient times to carry salt from the salt pans of Ostia, the port of Rome, into the neighboring country of Sabines.

The word "salary" shows the great value ancient man placed on salt. The term is derived from salt and in its original sense it indicated that money was given to buy salt. In other words, a Roman soldier's salt money was his salary. Until not so very many years ago, natives of Sierra Leone in Africa valued salt so highly that they were will to sell their wives and children for it.

A tax on salt has been levied in many countries. Back around the turn of the last century the British government in India attempted to increase the salt tax. Rebellion was threatened and the extra tax was removed the following year because of all the problems it caused. We've even had a salt war, here in the United States, yet few Americans will remember it being discussed in history classes.

We no longer pay salaries in salt, but we still recognize its great importance. However, nowadays it is such a cheap and common thing that we are included to give little thought to its origin and history, or to the methods by which it is obtained.

Common salt, or sodium chloride, is composed of the elements sodium and chlorine. Sodium is a curious soft metal which can be cut with a knife and is very difficult to keep pure. chlorine by itself is a deadly gas, and it seems strange that it should form a basic part of a compound so vitally essential to human and animal life.

Slat and other compounds of sodium are to be found everywhere, and wherever salt or any compound of sodium exists, and is made hot, it gives forth a special kind of yellow light.

By passing any light through a prism we can clearly detect the bright yellow lines that mark the presence of salt, or rather of the sodium in the salt. It is only natural, then, to turn our attention to the light that reaches us from the sun and the stars. No sooner do we do so than we find that the material which is in our bodies, which abounds in the sea, and which also forms a sort of rock upon the earth, is also abundant in the sun and in many of the stars.

The salt found in the seas is the accumulation of millions of years. Rivers flowing into the seas carry with them a certain amount of salt which has been washed from the earth through which the rivers pass. The amount of salt contained in the oceans is enormous. It has been calculated that there is enough to cover the whole surface of the earth to the depth of almost four hundred feet. This would be something like fourteens times all the solid land of Europe above sea level.

Much of the salt we use today comes from the great veins or deposits of rock salt which are buried deep under the ground.

As we have seen, these deposits were formed by the drying up of ancient seas, which left their salt behind to be buried under layers of earth as time went on. Such salt beds are common. Often many beds or veins lie one above the other, separated by layers of rock.

In New York and Kansas there are solid slat beds over three hundred feet thick, and one at Sperenberg, Germany, is known to be over three thousand feet in thickness. The largest salt mine in the world is that at Wieliczka, in Poland. It is almost one thousand feet deep and extends three hundred feet below sea level. Over twenty-five miles of railroad were laid in this mine, all meeting at a central station carved out of gleaming white salt which reflects the light.

Other places on earth with great salt mines are:

• Kilroot, Ireland
• Khewra, Pakistan
• Tuzla, Bosnia
• Bochnia, Poland
• Hallstatt, Austria
• Salzkammergut, Austria
• Rheinberg, Germany
• Slanic, Romania
• Provadiya, Bulgaria
• Avery Island, Louisiana
• Cheshire, England
• Worcestershire, England
• Detroit, Michigan
• Goderich, Ontario, Canada

Those are just the more notable ones. The largest salt mine in North America is at Retsoft, New York. Its miles and miles of underground passes cover an area almost as large as New York City.
The thickest vein of salt ever discovered is still at Avery Island, Louiaiana. The oldest vein of salt in the western world is here.
Michigan, New York, Ohio, Kansas, Louisiana, Texas and California are all salt producing states. Salt is also taken from the Great Salt Lake, Utah.

The five biggest producers of salt today are:

• China
• United States
• Germany
• India
• Canada

When we think of all these great mines, we should wonder where all the salt can go. Millions of tons a year are consumed as food. Other millions of tons are used fro a vast variety of purposes, for salt plays an important part in industry, agriculture, chemistry and medicine, as well as in the homes of all of us.

There are two principal methods used today to obtain the tremendous quantities of salt we consume. The evaporation method of salt brine, or a mixture of salt and water I've already discussed above, however, the other method is by mining rock salt from the underground beds or veins. This latter process is quite similar to that used in mining coal.

The salt brine used in the evaporation process is either surface brine coming from sea water or salt lakes, or brine from wells. Brine from wells may be natural or it may be made artificially by pumping water into wells drilled from the surface of the earth into the underground deposits of rock salt.

Today large scale salt producing companies make use of the two evaporating methods -- the vacuum method and the grainer method. A third method, the Alberger process, is used in one of the large salt refineries in the Untied States.

Salt produced by vacuum-evaporation process is known as "granulated salt," the most familiar form of which is table salt. There are many other important uses for granulated salt, however. Many branches of modern industry require a wide variety of types and grades of salt.

Vacuum-evaporated salt is produced in cast iron vessels that are called vacuum pans. The brine is fed into these pans, heated by steam, and kept in motion to bring it in constant contact with the heating arrangement. When the brine begins to boil, salt crystals form and drop through the bottom of the vacuum pan into the salt catcher.

They are removed from this catcher from time to time. The evaporation process carries on continually. From the vacuum pan the salt is pumped to filters which removed the excess moisture.

The rotary dryers, to which the salt is next carried, give to the grains, the dryness of the desert sands. After it leaves these rotary dryers the salt is conveyed to the automatic weighing and packing machines.

Grainier salt, which used to be commonly known as "flake slat," is produced by allowing brine to flow into tremendous pans, over one hundred feet in length, and between ten and twenty feet in width.

It is then heated by means of steam. When the crystals of salt form, they float on the surface of the brine, for in the grainier process the brine is not agitated as it is in the vacuum-evaporation process. When still other crystals form, they gather on the first one to form "hoppers" or flakes.

As a crystal, or flake grows, it becomes heavier and skinks to the bottom of the grainer pan. The flakes are then removed and put through a drying and grading process.

Grainier salt, a salt more coarsely grained than that formed in the vacuum pans, is widely used in the production of many food products, such as salted fish, cured meats, and butter.

Mining rock salt is the other great process by which we obtain our salt supply. Rock salt also plays in important role in food industries. It is used as a refrigerant in making and storing such things as ice cream and in making ice itself. The chemical, paper and textile industries use great quantities of rock salt.

It is also used as an economical way to melt ice, and we often spread it on icy streets and pavements to prevent people and vehicles from slipping and skidding.

Men descent into the rock salt mines just as they do in a coal mine, the great difference being that the walls are white instead of being black. Machines cut into the salt and loosen it from the tunnel walls. Charges of dynamite break it free.

Then the gleaming salt chunks are loaded into mine railroad cars and taken to giant crushers, where the large lumps are crushed into smaller sizes before salt is carried to the surface. Above ground, it is further crushed, screened, and graded to the required commercial sizes.

It is then packed in bags and is ready for shipping to the markets of the world. The containers you see on grocery shelves are produced by machines that fill each container with exactly the right amount of salt -- all without the touch of human hand.