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-⢠67 - Removal of the d i e l e c t r i c from the metal involves the breakage of chemicaJ bonds. Depending on the composition - the surface of glasses i s formed bj' negative- l y charged 0 ~ and OH" groups - metal ions may be removed from the mecal and re- tained by the glass svirface. Such a transfer of ions from the metal to the glass i s one of the elementary processes causing f r i c t i o n e l e c t r i c i t y . Recent work on the surface chemistry of glass makes i t possible to explain the e l e c t r i c charges observed i f pieces of glass of i d e n t i c a l composition but d i f f e r e n t heat treatment are rubbed together. F r i c t i o n between glass and ice crystals may lead to strong e l e c t r o s t a t i c charges because of the formation and breakage of hydrogen bonds be- tween the glass surface and the water molecules. I n connection w i t h f r i c t i o n e l e c t r i c i t y of glasses i t i s of i n t e r e s t to learn that heavy metal ions i n the glass surface decrease the e l e c t r i c a l charge on rubbing. THE STATUS OF SYNTHETIC MICA M. D. Heyman Integrated Mica Corporation Woodmere, N. Y. The purpose of t h i s paper i s to evaluate the following? 1. The German discovery. Although there i s a record of the Westinghouse Company having applied f o r a patent, and possibly having made some t i n y flakes of synthetic mica, the f i r s t sizable pieces were made by the Germans. Several pieces were produced that measured over four square inches. However, t h i s appears to have been a rare occurrence, and the Germans never got out of the early experimental stages, and did not produce the mica commercially; i n f a c t , no stock of such mic'a was ever found i n Germany, and the fabricators of that product did not know anything about i t . 2. The American development work since 19^6. The f a c t that 90^ of our mica supply comes from India, and that a conclu- sive search during the l a s t war has proven that the United States cannot look forward to a home mica industry, due to lack of m a t e r i a l and high labor costs, has prompted our Government, c h i e f l y the Bureau of Naval Research and the Army Signal Corps, to attempt to develop synthetic mica. This was largely done through contracts w i t h certain concerns. Although more than two years have gone by since t h i s program started, technical information has not been generally availableo A new fiirnace i s being b u i l t at Norris, Tenn. from which good results are expected; but so f a r i t i s not known what size crystals can be produced, or what the cost of the mica w i l l be. At the present time, block mica that i s too smell to cut a seven-eighths inch diameter disk i s not considered as having commercial value.
