  Da Rocha and Rodigues (RR) claim (i) that in classical electrodynamics in
vector calculus the distinction between polar and axial vectors and in exterior
calculus between twisted and untwisted forms is inappropriate and superfluous,
and (ii) that they can derive the Lorentz force equation from Maxwell's
equations. As to (i), we point out that the distinction of polar/axial and
twisted/untwisted derives from the property of the electric charge of being a
pure scalar, that is, not carrying any screw sense. Therefore, the mentioned
distinctions are necessary ingredients in any fundamental theory of
electrodynamics. If one restricted the allowed coordinate transformations to
those with positive Jacobian determinants (or prescribed an equivalent
constraint), then the RR scheme could be accommodated; however, such a
restriction is illegal since electrodynamics is, in fact, also covariant under
transformations with negative Jacobians. As to (ii), the "derivation" of the
Lorentz force from Maxwell's equations, we point out that RR forgot to give the
symbol F (the field strength) in Maxwell's equations an operational meaning in
the first place. Thus, their proof is empty. Summing up: the approach of RR
does not bring in any new insight into the structure of electrodynamics.
