the british physicist p.m.s. blackett provided a major impetus to paleomagnetism by inventing a sensitive astatic magnetometer in 1956. his intent was to test his theory that the geomagnetic field was related to the earth's rotation, a theory that he ultimately rejected; but the astatic magnetometer became the basic tool of paleomagnetism and led to a revival of the theory of continental drift. alfred wegener first proposed in 1915 that continents had once been joined together and had since moved apart. although he produced an abundance of circumstantial evidence, his theory met with little acceptance for two reasons: (1) no mechanism for continental drift was known, and (2) there was no way to reconstruct the movements of the continents over time.