The limit of four years is not an absolute limit.

Death is a limit.

A 'conditional limitation,' as the lawyers call it, is imposed on his tenure of office.

And when the President dies his term of four years, for which he was elected and during which he was to hold provided he should so long live, terminates and the office devolves upon the Vice-President.

For what period of time?
_For the remainder of the term for which the Vice-President was elected_.