"The Einstein Theory of Relativity" is the short version (587 m) of the lost American long version (1219 m) of Hanns Walter Kornblum's original German feature "Die Grundlagen der Einsteinschen Relativitäts-Theorie" from 1922 that is also lost.
The Einstein Theory of Relativity (1923) is currently not available on any services.
Dave Fleischer
Out of the Inkwell Films
Justice League: Crisis on Infinite Earths Part Two
Justice League: Crisis on Infinite Earths Part One