a . e .
HIGH SCHOOL CHEMISTRY
Salt, the Most Useful of Mineral Substances Historic Commodity Plays Vital Role in Foods, Agriculture, and Industry E. R. TUSTIN, .IH. lrurrr s t w
D e r ~ c !PROM .
Salt Company, Ne7r York GI>
LAST
NOTE
UA V I N C I ' S "THE SUPPER." BAGCONTAINING TK A N D O v m r m t N R n S A L T CELLARA T H A N U OX.JUUAS
RAS MOVKS ~
ALT is the most common mineral in existence, hut from spoiling-hence the sacred significance with do you know of any more useful? Since early which salt was endowed. times salt has been assodated with value and worthiWe find that whenever sodium chlxide is named ness, as witness the Biblical statement, "Ye are the in the Bible it is done so in language stamping it as a salt of the earth" (Matthew 5: 13). most important essential. Especially do we notice To primitive people salt represented something this in directions for religious services. When Elisha that was not perishable and that would keep foods sweetened the waters of Jericho he cast salt into them, 503
S
illustrating the purifying properties of salt, for he said, "I have healed these waters" (I1 Kings 11). SALT AS A COVENANT
I n Eastern countries i t is a time-honored custom to place salt before strangers as a token and pledge of friendship and good will. ..
.
-
overturned salt cellar before Judas in the painting, "The Last Supper." Through the ages belief in the sacred properties of salt persisted. I n Scotland salt was in high repute as a charm, and the salt box was the first chattel to be removed to a new dwelling. When Robert Bums, in the year 1789, was about to occupy a new house at Ellisland, he was escorted on his route along the banks of the river Nith by a procession of relatives, and in their midst was carried a bowl of salt resting on the family Bible. Peculiar notions about the magical properties of salt were common among American negroes. In some regions a new tenant would not move into a furnished house until all the objects therein had been thoroughly salted, with aview to the destruction of witch-germs. SALT USED AS MONEY
Roman soldiers received part of their pay in the form of salt, from which comes our modern word "salary" and the expression "worth his salt." Among the old Chinese, salt was considered second in value to gold only, and i t held an important place in the monetary system of the Great Moguls. Marco Polo, in the 13th century, writes of flat cakes of salt, bearing the stamp of the Great Kahn, which were used as money in Tibet. Even today salt takes the place of money in certain parts of Africa, Mexico, and the South Sea Islands. When the hordes of Mussolini invaded Ethiopia, the native hunters refused to accept Italian currency in exchange for skins, but instead, used coinshaped discs of salt. Right here in America, each member of the Onondaga tribe of Indians receives from New York State an annual payment of salt, in accordance with an old treaty, as part compensation for ceding 7300 acres of land in 1813. The antiquity of the practice of using salt in conh a t i o n of an oath is shown in the following passage from an ode of the Greek lyric poet, Archilochus, who flourished 2000 years ago: "Thou hast broken the solemn oath and hast disgraced the salt and the table."
Even a t the present time, Arabian princes are wont to ratify an alliance by sprinkling salt upon bread, exclaiming, "I am the friend of thy friends, and the enemy of thine enemies." During the Indian Mutiny of 1857 a chief motive of self-restraint among the Sepoys was the fact that they had sworn by their salt to be loyal to the English Queen. SALT SUPERSTITIONS
The widespread notion that the spilling of salt produces evil consequences was probably due to the sacred character of salt in early times. Anyone having the misfortune to spill salt was supposed to incur the anger of all good spirits. Leonardo da Vinci evidently had this superstition in mind when he portrayed an
THE SALT CELLAR
The Romans considered salt to be a sacred article of food, and it was a matter of religious principle with them to see that no other dish was placed upon the table before the salt was in position. With the peasant, a shell served as a receptacle for salt, but a t the repast of the wealthy citizen a silver salt cellar, which was usually an heirloom, was placed in the middle of the table, and this custom prevailed in England in early times. Medieval salt cellars were often elaborate pieces of craftsmanship. Until the end of the 17th century, the rank of guests a t a banquet was indicated by their seating with reference to the massive silver salt cellar. At the head of the table "above the salt" sat the host and his more distinguished guests. The less noble sat "below the salt." In the 11th century the laws of King Canute provided that any person sitting a t a banquet above the position to which he was entitled should be "pelted out of his place by bones a t the discretion of the company." Those were the days of meat in abundance.
SALT IN WARPARE
A strategic part has been played by salt in great military engagements. Napoleon's soldiers on the celebrated retreat from Moscow died by thousands as the result of wounds whose failure to heal was attributed to prolonrred deprivation of salt. The same circumstance wasurepo:ed during the Paraguayan War of 1874. In our own country during the Civil War, one of the principal purposes of a Uniou campaign into Virginia was to capture a chief source of salt of the Confederacy located in Saltville. Nowadays salt plays an important new part with the armed forces as well as in civilian industry. Millions of salt tablets are used to replace salt lost through perspiration and thus help ward off fatigue. History is filled with illustrations of the economic pressure exerted on people by lack of salt. It has forced them to make war, build ships, roads, and cities, and enter into commerceon land and sea.
portant component of gastric juice. Upon receiving salt, the stomach changes its chloride component into hydrochloric acid for digestive purposes. The body divides salt into its chemical constituents with the greatest of ease, but it takes elaborate equipment to do the same thing industrially.
HOW SALT IS OBTAINED
Old manuscripts reveal that 5000 years ago in China salt was obtained by boiling and evaporating the ash from sea weeds. In America scarcely 100 years ago Indian tribes, if living near the ocean, evaporated sea water in open trenches. Those inland obtained salt by boiling and evaporating the brine from salt springs to which buffalo and deer were wont to come. Early American settlers, living in the interior, experienced great perils and hardships to obtain salt. As might be imagined, salt was expensive and a t the time of the War of 1812 it cost $5.00 a bushel. Little change was made in the method of salt manufacture through the ages until 1886, when Joseph Duncan, an American, started a salt company a t Silver Springs, New York. He employed a revolutionary new process-the vacuum pan process-in use today. This method produces a uniformly grained salt of very high purity. Wells are bored and water is piped down to salt strata in the earth. The resulting brine is pumped up, liltered, and purified. After evaporation in vacuum operators, usually multiple effect, the salt is drawn off and conveyed to dryers. I t is then screened to separate crystals of different size used for various food and industrial purposes.
Electricity is the key to the composition of the salt crystal. When a strong electric current is passed through molten salt, the hot mass is separated into a silvery white metal, sodium, and the greenish yellow gas, chlorine. Both elements are widely used by the chemical industry. Sodium has been employed for many years in the manufacture of dyes, insecticides, and photographic materials, and more recently in making the tetraethyl lead used in aviation gasoline. Operation of airplanes a t the terrific speeds necessary in this war USES FOR SALT WIDESPREAD is also facilitated by the use of sodium in the valve The more civilization has progressed the more de- stems. By this means, heat from the engine is conmand there has been for salt, and today over 4,000,000 ducted rapidly to the radiating system and danger of tons of evaporated salt are required annually for the overheating is minimized. The wearing parts of tanks, trucks, and planes could home and for a vast number of farm and industrial uses. This amounts to 60 pounds per capita and does not take the terrific punishment to which they are not include the almost equal amount of rock salt subjected if the pinions and gear surfaces had not been "case hardened" in a bath containing molten mined. The human body requires about one-half ounce of sodium cyanide, another member of the salt family. Shortages of copper and brass for shell cases have salt per day, or 12 pounds per year, to enable the various glands to hold the amount of water they need for led to the use of steel, plated with copper or zinc to proper functioning. Salt is also the source of an im- insure a smooth, non-rusting surface. Sodium cyanide
and the cyanides of copper and zinc--all members of the salt family-are required to plate these shells. Likewise from salt comes sodium peroxide, with which millions of yards of cotton fabrics for the armed forces are bleached to permanent whiteness. Chlorine, the other element derived from salt, is equally versatile. Added to drinking water in small quantities, it has saved thousands of lives by destroying bacteria. On the other hand, chlorine is used in making deadly war gases such as phosgene and mustard gas. From hydrochloric acid, another salt derivative, and acetylene gas comes neoprene synthetic rubber, referred to by the Baruch Committee as the "one synthetic material of a quality to be the full equivalent of natural rubber for combat and heavy duty tires." Neoprene is also used to coat fabrics for blimps. Other salt-derived products, the chlorinated hydrocarbons, are required in enormous quantities to clean the metal parts going into tanks, trucks, ships, planes, and guns. And one of these compounds is used in making smoke screens to conceal the movements of United Nations forces. Other chlorine compounds include fire-extinguisher fluids, refrigerants, and anesthetics. In the home, salt solutions have long been used as a gargle and dentifrice, but chemicals from salt are now needed to make the new "sulfa" drugs, vitamins, and other pharmaceuticals. Radioactive salt, made by combining chlorine and sodium bombarded with Tcw V ~ l r wOF QVADKUPI.*: EFFECT\-ACUUM PAN~ ~ Y A P O K A I O X S deuterons, can be accurately traced as it passes through AT REPINERY OP WORCESTER SALTCOMPANY. STEAMBELTS the various parts of the body and accordingly is a new W ~ T ~BOIL I N AND E V A P O R ATTH ~ E BRINE,MA~NTAINED ONDGR IS physiological tool. S u c c m s r v ~HICHKR ~ ~ VACUUMS. ULTIMATEFUELECONOMY Ttrus OBTAINED
