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The Intentional Use of Antimony and Manganese in Ancient Glasses
Title and Abstract in English, French and German, while paper is in English. The use of manganese as a colorant in ancient glasses has long been recognized and the recent X-ray diffraction measurements of Turner and Rooksby have established that compounds of antimony were used extensively as opacifiers in such glasses. The analysis at Brookhaven National Laboratory of some three hundred ancient western glasses of the second millennium B.C. through the first millennium A.D., of which more than two hundred contained either or both of these elements in sufficiently great concentrations to indicate deliberate additions, not only has provided confirmation of these observation but also evidence that both of these elements were used extensively to counteract discoloration due to iron in glasses intended to be clear and colorless. As is well known in the case of manganese the different behavior of antimony in different glasses appears to depend upon its chemical valence. The technique of decolorizing glass by means of antimony was introduced at about the seventh century B.C. and the similar use of manganese became widespread during the first century A.D. In the following period through the fourth century the alternate or combined use of these decolorants forms an interesting and complex pattern correlating with chronological and geographic origins. After the fourth century the use of antimony as a decolorant essentially seems to have ceased.
A New Determination of the Ratio of the Electromagnetic to the Electrostatic Unit of Electricity [Part 1]
Report issued by the Bureau of Standards over new determinations made in regard to units of electricity. Methods and equipment used are discussed. This report includes tables, illustrations, and photographs. Part 1 includes sections I through VI.
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