Thursday, May 20, 2010

Alchemy in Ancient Egypt


Alchemists pioneered one technique that laid the foundations for much of modern chemistry: they experimented. The mystical-religious thinking surrounding alchemy also played a significant role, giving rise to beliefs that were later to become precepts of modern chemistry: conservation of matter, phase changes, and energy transfer. Alchemic mysticism connected the transformation of solid substances into liquids and vapors with the transformation of the human body into the soul. Sublimation, in which a solid converts directly into a vapor, in particular seemed analogous to the spirit leaving the body, and the magical recrystallizations out of a melt or vapor were connected with ideas of reincarnation and rebirth.

Alchemy was philosophy. Alternatively called hermeticism, alchemy had as its primary intention the regeneration of the human soul from its present sensory-dominated state into its original divine condition. It was about raising the life essence of things—metals in particular—to a nobler form.

It's unclear where alchemy originated; some scholars say it began in Egypt and was filtered to China; others say it began in China. Alchemic ideas are seen in Hindu writings from 1000 B.C. in the Arthava Veda. In any case, alchemic ideas were seen far earlier in India, Egypt, and China than in Greece.

The Greeks thought of Egypt as the source of earliest alchemy, and they admired the ancient Egyptian skill in "enameling, glass-tinting, the extraction of plant oils, and dyeing—all dependent on chemical knowledge," according to John Read. "For such reasons, Egypt, or Khem, the country of dark soil. . . has often been pictured as the motherland of chemistry," he writes. The word chemeia, Greek for a "preparation of silver and gold," may have roots in Khem. Other sources claim that chemyia has origins in word meaning to pour, while scholar Bruce Bynum says that Kem, and al-kemit (as in "alchemy") referred not to Egypt's soil but to the earliest people of the upper Nile who established the Nubian, or Kemetic, civilization. They were black Africans. Hence, to the Greeks Kem came to mean "land of the blacks." Other researchers believe that the Egyptian ideas came from Persian, Chaldean, and Hebrew sources.

Third-century A.D. papyri from Thebes, copied from even earlier texts, may be the earliest records of alchemic schemes for turning base metals into silver and gold. The papyri contained little theory but much practical information on the alloys going into different metals. Alchemy was, however, related to Egyptian philosophical and religious views, and, in a sense, to mummification, according to Eduard Farber:

Egypt, the land of the black earth, was devoted to the cult of the dead. The god Osiris is revived from death after he has been ritually wrapped in bandages. To the Egyptian's mind, this indicated a valid analogy to the fact that minerals are bandaged and entombed in black lye to revive them into metals.

Priests presided over this "embalming" of metals, which came from the dark earth to be transformed (they hoped) into gold. The Egyptian practice of embalming the dead was a logical extension of this belief and, according to Farber, an indication of how matter acted powerfully on the human spirit and life. Life, spirit, and physical elements were interconnected in ancient Egyptians' minds.

This concept of material transformation must have fascinated early Egyptians as they watched metals change color and form after heating or undergoing other processes. The later Alexandrian alchemists (fourth through seventh centuries A.D.) emphasized a color progression in making gold: black was the first stage, from fusing "base metals" such as lead, tin, copper, and iron, or lead and copper with sulfur; bleaching was next, accomplished by firing the black compound with arsenic, silver, mercury, antimony, or tin. Next the substance was yellowed using gold or a lime-sulfur mixture. Finally the color violet prevailed. Violet-colored gold seems odd (and less than authentic) to us, but to the Egyptians this was a kind of heightened gold, the essence of gold, something that was seen as so powerful that it acted like "a yeast" to transform the metal into a spiritual substance. The concept of yeast was seminal in ancient thinking, signifying something very tiny that causes huge changes. In a sense yeast is a precursor to chemical ideas of catalysts or enzymes and is related to the Chinese and later Arabic elixirs of life.

Keeping in mind the Egyptian connection of physical matter with spirit, the vapor of distillation during these processes was associated with spirit, while the remaining "base" material was the body, the corpse. This clearly relates to the chemical process of sublimation, in which solid matter directly turns to gas. The transformation of substances is an early way of thinking about the phase changes of matter from solid to liquid to gas.

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Embalming was the first step to take the human spirit from its dead body to reincarnation. The Greek Herodotus (fifth century B.c.) describes the process:

First they draw out the brains through the nostrils with an iron hook, raking part of it out in this manner, the rest by the infusion of drugs. Then with a sharp stone they make an incision in the side, and take out all the bowels; and having cleansed the abdomen and rinsed it with palm wine, they next sprinkle it with pounded perfume. Then, having filled the belly with pure myrrh, cassia and other perfumes, they sew it up again; . . . they steep it in natron, leaving it under for seventy days. . . . At the expiration of seventy days they wash the corpse, and wrap the whole body in bandages of waxen cloth, smearing it with gum, which the Egyptians commonly use instead of glue.

The natron in which the body is steeped occurs naturally in Egyptian lakes. Chemists debate what natron was; some label it a sodium carbonate and bicarbonate precipitant, others a sodium aluminum silicon oxygen salt. It is now believed that the steeping in natron killed bacteria and dehydrated cells, while wrapping the corpse and sealing it in a tomb kept it from moisture and air. "All in all," write Cathy Cobb and Harold Goldwhite in their book Creations of Fire: Chemistry's Lively History from Alchemy to the Atomic Age, "the process was not much more mysterious than salting pork." (The Hawaiians also preserved bodies by gutting and filling them with salt obtained from evaporated seawater. A body treated in this manner was termed ia loa, long fish.)

As much as gold was revered in ancient Egypt, the occupation of goldsmith was not appealing to everyone. An ancient instruction book tells how Dua-Khety, a man living in the Middle Kingdom in Sile, wished to place his son Pepy in writing school rather than have him seek a profession as a goldsmith. "I have seen a smith at work before his furnace door, his fingers like [the claws of] crocodiles. He stinks more than fish roe." The smell refers perhaps to the fumes resulting from the many chemical procedures done to gold, the curled fingers perhaps a symptom of heavy-metal poisoning. Still, this did not deter others from falling prey to the allure of gold.

The desired end product of alchemy, gold, is found pure in nature and dates from the Stone Age of Egypt. However, the earliest Egyptians could not separate gold from silver. Sometimes Egyptian gold was so rich in silver it seemed a different metal, variously dubbed white gold, asem, or electrum. The nineteenth-century French chemist Marcelin Berthelot analyzed artifacts from the Twelfth Dynasty (ca. 2000 B.C.) and found the metal to contain around 85 percent gold and 15 percent silver. Later (circa 1300 B.C.) methods of separation involved heating the gold-silver alloy repeatedly with common salt, which eventually transformed the silver into silver chloride that would pour off into the slag.

The two papyri of alchemic recipes found at Thebes were first translated into Greek and then into Latin, the version Berthelot analyzed. The papyri are a collection of chemical recipes for making metallic alloys; producing imitations of gold, silver, or electrum; dyeing; and other related arts. The formulas are unabashed about their intended deception, so as to whether Egyptians saw no contradiction between "real" and "fake" gold, or whether the writer(s) were of a more practical nature than the priests, we can only speculate. Berthelot explains:

The parts dealing with the metals are largely concerned with producing passable imitations of gold, silver or electrum from cheaper materials, or with giving an external or superficial color of gold or silver to cheaper metal. . . . There are often claims that the product will answer the usual tests for genuine products, or that they will deceive even the artisans.

Here is a recipe for fake silver (amalgamated tin) :

Tin, 12 drachmas [3.411 grams]; quicksilver, 4 drachmas; earth of Chios [white clay], 2 drachmas. To the melted tin add the powdered earth, then add the mercury, stir with an iron, and put it into use"

To make artificial pearls:

Mordant [fix] or roughen crystal in the urine of a young boy and powdered alum, then dip it in "quicksilver" and woman's milk.

"Crystal," in this case, probably refers to softer, absorbent, transparent stones rather than to quartz, which would not soak up the solution. "Quicksilver" is probably fake mercury, made perhaps of mica or fish scales. Today, of course, it is more problematic obtaining young boys' urine and woman's milk. Urine, an alkali, was mixed with alum (potassium aluminum sulfate) to fix colors. We're not sure of the purpose of woman's milk.

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The making of skin creams and perfumed oils was highly developed in Egypt, as well as in Mesopotamia. Salves, ointments, oils, eye shadow, and nail paint protected the skin from the desert environment and had religious significance. In 2450 B.C., the sage Ptah-Hotep wrote, "If thou art a man of standing, thou shouldst found thy household and love thy wife at home as is fitting. Fill her belly; clothe her back. Ointment is the prescription of her body."

Animal fat or vegetable oils from castor, colocynth, lettuce, linseed, olive, and safflower served as the base to which aromatic oils were added. Oil from anise, cedar, cinnamon, citron, mimosa, peppermint, rose, and rosemary were popular. The method of extracting the oils is uncertain but could have involved boiling mashed herbs in a pot covered with fat impregnated cloth, the fat then soaking up the scent, a method still used by peoples along the Nile. Other methods include steeping flowers in fat until the odor was taken up by the fat, and dipping flowers in hot oils and straining off the liquid. Egyptians most likely expressed the oil by squeezing the ingredients in a cloth bag using wooden sticks. R. J. Forbes, a historian of technology, indicates that "milk, honey, salts and such aromatic gun-resins and oleo-resins" were included in beauty products, some of which probably fixed the volatile nature of the oils.

Cosmetic recipes were set down in a sixteenth-century B.C. text, the Edwin Smith Surgical Papyrus, which apparently was a copy of a much earlier document. Its begins by stating, "Beginning of the Book of Transforming an Old Man into a Youth," a sentiment close to modern people's use of cosmetics.

Recipe for transforming the skin: Honey 1, red natron 1, northern salt 1. Triturate [pulverize] together and anoint therewith.

Honey and milk were common bases for cosmetics in Egypt and Mesopotamia. Forbes compares this recipe to modern skin lotions that include "alcohol, glycerin, lactic acid (85 percent), water and perfume." The Egyptians also practiced dandruff control, using potions composed of ground and roasted barley, bran powder, and soft grease, topped off with applications offish oil and hippopotamus fat. Given shortages of hippo fat, modern dandruff shampoos rely on soft greases such as beeswax, lanolin, petrolatum, olive oil, or liquid petrolatum to dissolve the dry cuticle. The Egyptians also used powdered antimony and green malachite for eye shadow.

Natron was used both as a bleach for linen and as a kind of soap mixed with clay. The importance of soap is demonstrated by the fact that natron and other soaps made from soda and castor oil were overseen by the Egyptian authorities, who taxed the launderers' use of these materials. Wool was cleaned with ashes (which would provide alkaline carbonates as reagents) and clay-water, which would work together as an abrasive substance.

The Egyptians concocted a wide range of dyes, including purple, red, rose, yellow, green, and blue, made from safflower, orseille, woad, mulberry juice, pomegranate blossoms, cinnabar, and iron oxide. The prize of the Egyptians was kermès, the dried pulverized bodies of female scale insects they used to make red and purple dyes. Of course, kermes's history predates its Egyptian use. Pre-eighteenth-century B.C. Persians dyed their rugs with kermès, which is the root of the words "crimson" and "carmine." Blue dye was also popular, but we won't go into the details of its fabrication here. Suffice it to say that, once again, it involves urine. Also pivotal to Egyptian dyeing was something called the Phrygian stone, which, according to Pliny (writing in the first century A.D.), was a pumice-like stone soaked in wine and then heated three times. When wool was boiled with the Phrygian stone, mixed with algae, and washed in seawater, it would turn purple.

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