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#Mon Aug 09 11:59:44 CEST 2010
Text__wgw10KOcEd-WfYQ0GneCwQ_text=It follows from the theory of relativity that an electron's mass depends on its velocity.  Other theories also predict such a change in mass, although the change is not the  same size.  Walter Kaufmann deflects electrons in a tube with a magnet. He can  calculate an electron's mass from the curve of its path. His initial test results seem to  contradict Einstein's theory.   
Text__wgw10KOcEd-WfYQ0GneCwQ_title=Part of an Experimental Setup by Walter Kaufmann