On the Small Amplitude of Magnetic Secular Change in the Pacific Area.
It has been suggested that toroidal fields in the earth's fluid metallic core are brought to the surface to provide changes with time in the geomagnetic field. The centers of secular change thereby produced then drift slowly westward. If there is a downflow of fluid, the secular change pattern may then be reduced in intensity relative to those regions experiencing an upflow. Data on the geomagnetic field (1912-1955) are used to show that such a downflow is probable in the Pacific region, and that this explains the small amplitude of secular change observed in that area. 11 pp. Bibliog.