On the influence of the moon on the magnetic direction at Toronto, St. Helena,and Hobarton

Having noticed the inference drawn by M. Kreil from the magnetic observations at Milan and Prague, that the moon exercises an influence on the magnetic direction at the surface of our globe, cognisable by a variation in the declination depending on the moon’s hour-angle and completing its period in a lunar day, the author proceeds in this paper to state the results of an examination, analogous to that pursued by M. Kreil, into the influence of the moon on the magnetic declination at the three stations of Toronto, St. Helena, and Hobarton. The observations employed in this investigation consisted of six years of hourly observation at Toronto, five years at St. Helena, and five years at Hobarton, forming, exclusive of observations omitted on account of excessive disturbance, a total of 105,747 observations.