50 lines
7.5 KiB
TeX
50 lines
7.5 KiB
TeX
\section{Egypt}
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Man-made glass apparently originated in the pre-history of Eastern Mediterranean countries, perhaps Egypt. Mesopotamia seems to have had a flourishing glass industry around 2000 BCE, manufacturing non-transparent beads and other simple objects in fairly large quantities, with the occasional finely molded piece for the royal customer. \footnote{Phillips, Ency of Glass, p.20}
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During the reign of Tuthmosis III (1501\EnDash{}1447 BCE) Egypt invaded and conquered part of western Asia. Egypt's first glass factory was found dating from that period, suggesting that one of the spoils of war might have been skilled glass craftsmen. In any event, Egypt was a synonym for luxury and culture in the ancient world, and although Mesopotamian glass making continued to flourish, it was the Egyptians who required and paid for the finest skills and materials, making Egypt the glass making capitol of the time. In fact, the earliest glass vessels that can be dated with some certainty are three turquoise blue vases with the cartouche of King Thothmosis III.\footnote{One in the British Museum, another in the Munich Antiquarium, and the third at the Metropolitan Museum of Art in New York. Phillips, p.11}
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Similar specimens from this period indicate glass-making reached high standards of efficiency. Egyptian vessels of colored glass found ready markets in the Middle East countries. This naturally led to the spread of glass-making knowledge, practiced in other countries bordering the Mediterranean.
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Then in the fourth century BCE, Alexander the Great conquered the known world, and founded Alexandria in 331 BCE. Alexandria became a center of ancient world, and glass making 'followed the money'. Alexandrian glass products quickly captured export markets long been enjoyed by Egypt, and those exports reached as far as England and Scandinavia. \footnote{Phillips, p. 11} Apparently, Alexandrian glassmakers introduced their craft to Rome about the beginning of the Christian era.
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It was about this time that we meet another of our Extraordinary People: an unknown crack-pot who had the crazy idea of taking a metal pipe, dipping one end of it into a pot of molten glass, and blowing. Mind you, glassblowing requires much hotter furnaces than other glass-working techniques. Furthermore, metal pipes were difficult to make and thus rare and expensive in ancient times. So our Extraordinary Person got their glass considerably hotter than was the norm, took their expensive metal pipe, stuck one end into the molten glass and blew a bubble. And humanity was forever transformed.
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This technique was almost certainly invented in Syria in the first century of the Christian era. There is no way of knowing how this invention came about\EmDash{}this method is quite unlike any method employed before in glass\EmDash{}or in any other material then or since (for example: there is no such thing as 'bronze-blowing'). Glassblowing allowed the skilled artisan to create a far greater variety of glass objects in far less time than casting or other glass-making techniques. This unprecedented idea\EmDash{}blowing a bubble of molten glass\EmDash{}must easily qualify as one of humanity's Truly Great Inventions.
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The nature of the ancient glassblowing pipe itself is an interesting question. The pipe needs to be able to not only stand the heat, but also the heat differential\EmDash{}at one end will be molten glass, the other end will be at room temperature. The pipe also has to be about 1.5 meters long (5 feet)\EmDash{}shorter than that and the glassblower will be burnt trying to get the end into the molten glass; longer than that and the pipe is unwieldy, especially with a big blob of heavy molten glass on one end. (You have to start with more glass on the end of the pipe than will end up in the finished piece.) Thus the pipe also has to be rather strong, both physically and thermally-it almost has to be metal to meet all these requirements.
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Although glass melts at about 650C (1200F), it needs to be considerably hotter than barely-melted to be 'blow-able'. Furnaces in modern glassblowing shops (with natural gas or propane fueled furnaces) currently keep the molten glass at about 1300C (2300F); ancient glassblowing shops (with wood-fueled furnaces) likely made do with lower temperatures.
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The Egyptians around 2500 BCE were making copper pipes to a diameter a little under 2'' by taking a flat piece of copper, rolling it into a pipe shape, and hammering the seam closed.\footnote{Sahura, Plumbing \& Mechanical, July 1989. The earliest cast iron pipe appeared around 1500 (Koeble, F. \& Hogan, W., Cast Iron Soil Pipe and Fittings Handbook, Cast Iron Soil Pipe Institute, 1994). Commonly used metals of ancient times include: lead which melts at 330C, brass at 925C, copper at 1100C, iron at 1150C (and glass at 650C), the melting point of alloys is considerably more complex. Modern pipe making received its big impetus from the making of gun barrels.} Thus it's clear that in ancient times they were capable of making, for example, a copper pipe that could have worked as a glassblowing pipe. Even in modern times, because molten glass is not only hot, but also corrosive, modern glassblowing pipes are expensive tools incorporating significant modern technology.
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Curiously, although glass was known in India, China and Japan, they did virtually nothing to develop it. Glass technology has been a peculiarly Western pursuit until modern times. \footnote{Macfarlane, A. \& Martin, G., ``A World of Glass'', Science Vol. 305, Sept. 3, 2004, p.1407\EnDash{}8}
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\EmDash{}
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Glass Factoid: The first mention of glass in western literature (with the possible exception of the Bible, depending on whether you classify the Hebrew Scriptures prior to the Christian era as 'Western literature') is in a speech by Cicero in 54 BCE in defense of Gaius Postumus at his trial:
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\begin{quotation}
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`Postumus' ships were berthed in Puteoli and merchandise was talked about and seen. In reality, those goods were nothing more than cheap imitations made from paper, linen, and glass; and, although many ships were loaded with these, the whole lot together could not equal the debt.'' \footnote{Pro Rabirio Posthumo XIV.40}
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\end{quotation}
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\EmDash{}
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Glass Factoid: Glass is mentioned in the (King James) Bible in eight places:
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Job 37:18 Hast thou with Him spread out the sky, which is strong, and as a molten looking glass?
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Is. 3:23 (v. 18: In that day the Lord will take away the bravery of their tinkling ornaments about their feet\ldots, and) the glasses, and the fine linen, and the hoods, and the vails.
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I Cor. 13:12 For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
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II Cor. 3:18 But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
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Rev. 4:6 And before the throne there was a sea of glass like unto crystal; and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.
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Rev. 15:2 And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God.
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Rev. 21:18 And the building of the wall of it was of jasper: and the city was pure gold, like unto clear glass.
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Rev. 21:21 And the twelve gates were twelve pearls; every several gate was of one pearl: and the street of the city was pure gold, as it were transparent glass.
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