Take at look at Einstein's famous little book, The Meaning of Relativity,
and you will see that he uses the modern notation regarding E and m and the
like, and clearly DOES NOT use m for some sort of "relativistic mass."
Sometimes with the convention that c=1 he writes expressions like
E sub 0 = m c^2 and E = mc^2/sqrt(1 - (v/c)^2)
and even E = mc^2 + 0.5 mv^2 + (3/8)mc^2 x (v/c)^4 + ...
but NOT E = mc^2.
Laurent Hodges, Professor of Physics
12 Physics Hall, Iowa State University, Ames, IA 50011-3160
lhodges@iastate.edu http://www.public.iastate.edu/~lhodges