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Science Frontiers ONLINE No. 139: Jan-Feb 2002 |
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Confusion That'S Hard To Cut Through
D.A. Stocks in SF#137 described how his Egyptian workers were able to cut through granite with copper saws with the addition of a little abrasive sand. Sure, it was slow, hard work, but it could be done. Stocks' experiments squelched the various speculations about the ancient Egyptians possessing superhard tools or being able to soften stone.However, C. Ginenthal writes that H. Garland and C.O. Bannister attempted to saw through granite back in the 1920s using essentially the same method employed by Stocks -- but without success. Garland and Bannister wrote a book on their experiments, from which Ginenthal has provided the following quotation:
A consideration of the [copper and abrasive cutting] process would seem to give support to the idea that a copper-emery [or other abrasive material] process might have been used by the first Egyptians, but the author [Garland] has proved by experiment the impossibility of cutting granite or diorite by any similar means to these. But the use of emery powder anointed with oil or turpentine, no measurable progress could be made in the stone whilst the edge of the copper blade wore away and was rendered useless, the bottom and sides of the groove being coated with particles of copper.
(Garland, H., and Bannister, C.O.; Ancient Egyptian Metallurgy, London, 1927, p. 95. (Cr. C. Ginenthal.)
Comment. Garland seemed wedded to emery as the abrasive. We wonder if he tried the silica sand that seemed to work for Stocks. Perhaps he did not try hard enough.
In his new book Sticks, Stones, & Shadows, M. Isler mentions Stocks' experiments and adds that successful results were also obtained by R. Hopkinsusing Stocks' method under the auspices of the Nova/ WGBH TV program "Obelisk" circa 1994.
Other Sites of Interest
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