Key points are not available for this paper at this time.
The analogy between gravitation and electromagnetic theory is discussed and used to obtain, for linearized gravitation theory, an analogue of the magnetic monopole. This analogue results in a quantization of mass. If a similar attempt is made to use the analogy between spin and charge it is found that Einstein's theory must be substantially modified to obtain an analogue of a magnetic monopole.
Dowker et al. (Fri,) studied this question.