08 May 2010

Israelite Engineering

Israelite Engineering
By Timothy S. Wilkinson

            In 1 Kings chapter 7, verses 23 through 26 Jeremiah records a truly incredible feat of ancient engineering: “And he [King Hiram of Tyre] proceeded to make the molten sea [a sacred water reservoir] ten cubits (175 inches) from its one brim to its other brim, circular all around; and its height was five cubits (87 ½ inches), and it took a line of thirty cubits (525 inches) to circle all around it. And there were gourd-shaped ornaments down below its brim all around, encircling it, ten in a cubit, enclosing the sea all around, with two rows of the groud-shaped ornaments cast in its casting. It was standing upon twelve bulls, three facing north, and three facing west, and three facing south, and three facing east; and the sea was above them, and all their hind parts were toward the center. And its thickness was a handbreadth (3 inches); and its brim was like the workmanship of the brim of  a cup, a lily blossom. Two thousand bath measures (11,600 gallons) were what it could contain.” (New World Translation of the Holy Scriptures)
            Had the “sea” been filled to its brim, it actually could have held 17,400 gallons. Empty, it would have weighed well over 30 tons. “There can be little doubt that it was one of the greatest engineering works ever undertaken in the Hebrew nation,” says former technical officer at the National Research Council of Canada, Albert Zuidhof, in Biblical Archeologist.
            According to verses 45 and 46 of the same chapter of 1 Kings, Hiram cast the sea “in the clay mold.” Archaeologists believe this to be a variation of the lost wax method. A wax model of the piece was crafted upside-down over a completed core mold. The artisans then built up a mold (probably of clay) over the wax model, completely encapsulating it. When the mold was dry, the whole mass was heated in some way so that the wax would melt and drain out of tubes set in the mold for this purpose. The tubes were blocked up, and liquid bronze was poured into the mold from the top.
            Many researchers have doubted whether or not the ancient Israelites had the technological and engineering skill to make such a casting. Heating, transporting, and pouring 30 tons of molten bronze is no small feat, and probably required some sort of a custom furnace made just for the job. The casting was done all at once, and the pressures generated inside the mold would have been tremendous.
            There is evidence, though, that Iron Age Israelites had developed remarkable engineering abilities. Water systems excavated at Hazor, Gibeon, Megiddo, and Jerusalem all attest to their skill.
            The Siloam tunnel was constructed to bring water from the Gihon spring in the Kidron Valley (outside the wall) into the city of Jerusalem. The tunnel slices through 130 feet of solid rock.
            The so-called “Hezekiah’s tunnel” is even more impressive. By Hezekiah’s day the Gihon spring had become even more unprotected from a besieging army. The king had the spring enclosed in rock to block access (or even visibility) from outside the wall. Then he commissioned the construction of a new tunnel to bring the water into the city. The tunnel remains to this day: 1,749 feet cut straight through the bedrock. Near its center one of the workers inscribed the following:

[…when] (the tunnel) was driven through. And this was the way in which it was cut through: While […] (were) still […] axe(s), each man toward his fellow, and while there were still three cubits to be cut through, [there was heard] the voice of a man calling to his fellow for there was an overlap in the rock on the right [and on the left]. And when the tunnel was driven through, the quarrymen hewed (the rock), each man toward his fellow, axe against axe; and the water flowed from the spring toward the reservoir for 1,200 cubits, and the height of the rock above the head(s) of the quarrymen was 100 cubits. (J. B. Pritchard (ed)., Ancient Near Eastern Texts (Princeton: Princeton University Press, 1969), p. 321).
The project involved the removal of 850 cubic yards of rock. Two teams, digging from opposite sides, met in the middle, only a little less than a foot out of alignment with one another. This would be an impressive feat with modern equipment, let alone Iron Age tools! Some researchers are convinced the builders used tapping sounds from above to guide the diggers, but the truth remains a mystery. What we do know for a fact is that ancient Israelite engineers had skills beyond what we might expect of the time period. We do well not to underestimate their abilities.

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