Page:Relativity (1931).djvu/165



is satisfied identically. That is to say: If we substitute their expressions in $$x$$, $$y$$, $$z$$, $$t$$, in place of $$x'$$, $$y'$$, $$z'$$, $$t'$$, on the left-hand side, then the lefthand side of (11a) agrees with the right-hand side.