Gold "Eureka, eureka, I have found it," Archimedes cried as he climbed out of the bathtub. Ever since that eventful day sometime in the third century B.C., the word eureka has come to symbolize scientific discovery. Well, just what earthshaking discovery did Archimedes make? No, he didn't discover the secret of life; he didn't find a new way to clean bathtubs, he didn't even discover the floating soap. He did, however, find a way to determine the purity of gold. King Hiero of Syracuse suspected that his goldsmiths had alloyed the gold he had given them to make a crown with silver. He asked Archimedes, the ranking scientist of the time, to determine if this was true. As Archimedes contemplated the problem in his tub, he came to the realization that a body immersed in water displaces its own volume of water. Therefore, for equal weights, a light metal will displace more water than a heavy one. Since silver is about half as dense as gold, the impure crown would displace more water than a piece of gold of the same weight. Eureka! Gold has always held a special fascination for all who gazed upon its brilliant shine, its lustre, its unique aura. The metal's glow reminded the Romans of the color of the sky at dawn and hence they called it "aurum" after Aurora, the goddess of the dawn. Even though gold is not the most precious metal, nor the rarest, it has always held a position of special importance. Since it is one of the few metals found in the free state, it was well known to the ancients. Its relative softness allowed easy moulding into ornaments, which often took on a divine character. Gold represented wealth and security. When the Israelites feared that Moses would not return from Mount Sinai, they found comfort m the building of the golden calf. The Egyptians, for their part, often buried pharaohs in golden caskets surrounded by gold artifacts to ensure prosperity in the next world. But perhaps it is the story of Jason and the Golden Fleece which best epitomizes man's desires to go to the ends of the earth in search of gold. According to Greek mythology, Jason and the Argonauts braved storms, falling rocks and attacks by harpies to bring the fleece to Greece from the kingdom of Colchis. The story probably was based on the fact that since antiquity, sheepskins have been used in Russian Georgia to collect gold from rivers. The tiny gold nuggets get stuck in the fleece as the water flows over it; when the skin is subsequently burned, the gold is left behind. How did gold get into rivers in the first place? Again, according to legend, King Midas was granted a wish by the god Dionysus. He wished that everything he touched would turn to gold. Midas soon realized his folly, as his water, food and women began to glitter. He begged to be released from this "curse" and was told to go and bathe in a nearby river...which may explain why we still find gold in rivers. Or perhaps, flowing rivers just erode away gold bearing quartz rocks, leaving tiny pellets of the metal in the riverbed. The first gold currency was introduced during the sixth century B.C. by king Croesus of Lydia. This was made possible by the discovery of the "touchstone," a type of rock which proved invaluable in determining the purity of gold. When scratched with solid gold, a yellow mark was left behind, whereas alloys with metals resulted in marks of other distinctive colors. The introduction of currency greatly facilitated trade and further emphasized the importance of gold, probably triggering various futile attempts to convert base metals into the precious substance. The practice of alchemy has of course been associated with these efforts, but in fact; the alchemists were after more than just the wealth that gold represented. To them gold was the substance of ultimate purity, seemingly imperishable and therefore immortal. If a method could be discovered to immortalize base metals like lead, perhaps the same could be done for human life. So they searched for the "philosopher's stone," the mythical substance which would not only convert metals into gold but would also yield the "elixir" of life. A solution of this material, or "aurum potabile," was regarded as the very embodiment of immortality. Needless to say, the alchemists are now dead and lead is still lead. Yet, the mixture of science and nonsense that these early chemists practiced laid the foundations for our modern studies of matter. They worked with acids and bases, with alloys, with sulfur and mercury. In fact, they believed that the latter elements when mixed in the right proportions would yield gold. They discovered that a piece of iron placed into a solution of copper sulphate becomes plated with copper. Because of the resemblance of copper to gold, undoubtedly some alchemists became convinced that with this reaction they really had found a method to make the royal metal. Their continuing search for the key to life resulted in the discovery of some important elements. In 1669, the German alchemist Hennig Brandt came up with the notion that since blood is the essence of life, it must contain the much sought after elixir. Furthermore, since the kidneys convert blood into urine, the substance should also be present in this bodily excretion. He evaporated a sample of urine to dryness, and was amazed when the residue glowed in the dark. He was surely convinced that he had found the philosopher's stone, but what he really discovered was the element phosphorus. The organic matter in the urine was reduced to carbon, which in turn reduced the naturally occurring phosphates to phosphorus. Not gold, but in the long run a much more useful element. In spite of the alchemists' vigorous efforts, the only way to obtain gold remained the time honoured, laborious search by hard. From South America came stories about "El Dorado," the Gilded Man. According to these legends, when a young Indian ruler came of age, he was covered in the finest gold dust and was rowed out to the center of a lake where gold and emeralds were dumped into the water as a sacrifice to the gods. When Europeans got wind of these tales, the first gold rush was on! The Spanish conquistadors never found their El Dorado but did manage to rob the Incas of virtually all their gold. The next great gold rush was also in America, this time in California. When gold was found in a farmer's field, the hopes of the nation were stirred. Young and old alike dreamed of panning for nuggets, hoping to find paydirt. For most, the effort did not pan out, but the forty niners did stay to populate California. They still play there today. In '98 came the word that gold had been found in the Klondike. Men by the thousands squeezed into rickety boats for the journey to the Yukon, where they had to beat conditions that a few months ago most could not even have imagined. They climbed the famed Chilkoot pass and walked for hundreds of miles to Dawson City. Contrary to their expectations the streets here were not paved with gold, but there certainly was gold in the surrounding hills. At least the early Klondikers did find their El Dorado. Today, most of the world's gold is mined in South Africa and the Soviet Union. In the most widely used process, the gold bearing rock is crushed and is then washed over copper plates whose surfaces have been covered with mercury. The mercury amalgamates with the gold, the amalgam is then scraped off and is distilled. The mercury evaporates and the pure gold is left behind. About four tons of rock are needed to eventually yield one ounce of gold. The pure metal is referred to as 24 karat, while 18 karat represents an alloy of 75% gold and 25% other metals. When these metals are nickel, copper and zinc, we have white gold; when silver is used, the product is the familiar yellow gold. The metal can even be given a reddish or greenish tinge by the judicious use of silver, copper and zinc. Gold is extremely unreactive. It dissolves only in "aqua regia," a mixture of hydrochloric and nitric adds. On account of its inertness, gold is ideal for use in dentistry. It is the most malleable of all metals, an ingot the size of a match box can he beaten into a sheet one ten thousandth of a millimeter thick, large enough to cover a tennis court. It is so ductile that an ounce can be drawn into a wire fifty miles long. A thin layer of gold is highly reflective and can be used on windows to save on air conditioning costs. It is such an excellent conductor of electricity that it is used extensively in computer circuits. In fact, a new industry has recently arisen, that of recovering gold from computer scrap. One ton of computer rubble can yield two pounds of gold. Compounds of gold have been found useful in the treatment of certain types of arthritis, with a new oral drug called auranofin showing especially encouraging results. At one time gold compounds were used to treat itchy skin, especially on the hands. Today, an itchy palm is still best treated with gold. If not available, money will do. Even though gold is no longer the basis for currency, it is still an important kern of international commerce. The largest stock is kept in the Federal Reserve Bank of New York. Here the gold of more than seventy nations is stored in vaults 85 feet below Manhattan. Four men work shifts to move the gold from the vault of one nation to those of another according to international dealings. The search for gold seems never-ending and sometimes takes on interesting forms. Some Soviet scientists have found that the microgram quantities of gold found in wine can be related to the gold content of the soil where the grapes used to make the wine were grown. Quite an interesting way of prospecting! It is rather amazing that so much value should be placed on a metal which has little practical significance. Men have spent lifetimes searching for it, attempting to synthesize it, have even died for it. Basically though, gold's only real value is that people want it. We are still alchemists in a certain way, searching for that pot of gold at the end of the rainbow. Somehow it represents the culmination of our hopes and dreams. We would love to have a Rumpelstiltskin to spin straw into gold for us, or a goose that lays golden eggs. But still in the back of our minds, we know that gold's warmth and beauty are superficial and indeed that "all that glistens is not gold,"...but it's still better than the Canadian dollar these days. Source: Fenster, A. E., Harpp, D. N., and Schwarz, J. A. The World of Chemistry Part II. McGill University, 1996 (p. 47-9).