A direct comparison of this relation with experiment is not possible
at the present time (1920; see\footnotemark\ Note, p. 48), owing to the fact that
-the changes in energy E[0] to which we can Subject a system are not
+the changes in energy $E_0$ to which we can Subject a system are not
large enough to make themselves perceptible as a change in the
inertial mass of the system.
$$ds^2 = g_{11}dx_1^2 + 2g_{12}dx_1dx_2 . . . . g_{44}dx_4^2$$
-\noindent where the magnitudes g[11], etc., have values which vary with the
+\noindent where the magnitudes $g_{11}$, etc., have values which vary with the
position in the continuum. Only when the continuum is a Euclidean one
is it possible to associate the co-ordinates $x_1 \ldots x_4$. with the
points of the continuum so that we have simply