  The charges of magnetic monopoles are constrained to a multiple of $2\pi$
times the inverse of the elementary unit electric charge. In the standard
model, quarks have fractional charge, raising the question of whether the basic
magnetic monople unit is a multiple of $2 \pi/e$ or three times that. A simple
lattice construction shows how a magnetic monopole of the lower strength is
possible if it interacts with gluonic fields as well. Such a monopole is thus a
hadron. This is consistent with the construction of magnetic monopoles in grand
unified theories.
