By Phil and Nancy Seff

      The use of window glass is generally considered to be a modern invention, and for centuries oiled paper or isinglass (thin sheets of mica) were used to bring sunlight indoors. Glass windows, however, have been found in the ruins of Pompeii. The rarity of such windows implies that glass must have been a luxury used only in the finer homes and buildings of that time.
      Glass is manufactured from silica, one of the most important and widespread elements in the earth's crust. In its mineral form silica is called quartz. A typical sandstone is usually composed of tiny grains of quartz held together by some material acting as a cement; often the cementing agent is also silica.
      Sand particles are formed from the weathering and erosion of a parent rock, usually igneous (rocks formed from a molten state). Logically, then, in its early stages, the sand will have particles of many other kinds of minerals mixed with the quartz grains, depending on the mineralogic content of the parent rock. Sand grains that lie along shores are subjected to the endless washing of waves and often become remarkably pure in quartz content. The water dissolves or carries away the softer minerals, leaving behind the harder quartz grains. Sandstone made solely of quartz grains is used regularly in the manufacture of glass.
      How the glass-making process originated has been lost in antiquity, but the Roman naturalist Pliny the Elder stated that glass was discovered accidentally by some Phoenician merchants. A great admirer of the Phoenicians, he credited them with many discoveries, including the invention of trade. Although Pliny was not adverse to exaggerating, scholars do accept his evidence that Phoenicians were the first traveling salesmen. Because they needed an efficient method of keeping records, they invented an alphabet from which every alphabet of the Western world has descended. Along with an alphabet came the equipment for using it: pen, ink and, of course, papyrus, parchment and finally paper.
      From their original home in the eastern desert, the Phoenician nomads crossed Asia Minor and settled in towns on the Syrian coast. With an unlimited supply of cedar to build ships, they became skilled and clever navigators. They traveled along the northern and southern rims of the Mediterranean Sea, establishing colonies, trading posts, harbors for their ships and sheds for their goods. They made many short-haul commercial trips, usually sailing by day and always within sight of land. The desert nomads had become the Bedouins of the sea.
      The Phoenicians not only traded their own products but also trafficked in tin from Spain, copper ore from Cyprus, and whatever else was available and of some value. Their travels also included the coastal area of West Africa. Upon landing, they spread their wares on the beach, whereupon they returned to their boats and raised a signal. Natives came out and laid gold beside the Phoenician goods as a barter price after which they retired. The mutual comings and goings went on until both sides were satisfied with the products and their cost. The Phoenicians would then sail away with the traded goods. Both Pliny and Herodotus reported that each dealer felt satisfied he had not been cheated.
      What particularly impressed the ancient world about the Phoenicians was their skill at long, daring sea trips. During the 7th century B.C., the Egyptian Pharaoh Necho, searching for a viable connection between the Mediterranean and the Red Sea, and having no notion of the size of Africa, sent some Phoenicians south of the Red Sea. For the next three years they circumnavigated Africa — a feat that would not be repeated for nearly 2,000 years, until the time of Vasco de Gama.
      The Phoenicians did stop each year at seed time to plant and harvest; then they continued their journey. When forced to sail at night, they navigated by a bright star in the constellation Ursa Minor. Then known as the "Phoenician Star," it is now called Polaris or, more commonly, the North Star.
      The intrepid explorers were unable to find a passage from the Mediterranean to the Red Sea. They did discover that there was none, and that such a passage would be useful. This was corrected in 1869 with the building of the Suez Canal.
      According to Pliny, on a long-forgotten evening after landing on the coast of Palestine near the mouth of the Belus River, the Phoenicians set about the task of preparing their evening meal. Being unable to find proper rocks on which to set their pots, they obtained some cakes of saltpeter from their ship's cargo and placed their cooking vessels on them before lighting a fire. The heat from the flames caused the saltpeter and quartz sand on the shore to melt. These combined into streams of an unknown fluid, which hardened into a translucent substance later known as glass.

Copyright © 1999, Deseret News Publishing Corp.
Phil and Nancy Seff are the authors of several science books, including "Our Fascinating Earth." Their column runs regularly in the Deseret News Science/Technology section.