Abstract
The vector-diagrams illustrating the change in the disturbance forces during the whole course of geomagnetic bays, show the same characteristics everywhere in the middle latitude regions; namely the disturbance force vector rotates clockwise with time in the forenoon and counter-clockwise in the afternoon, and the above characteristic corresponds to broadening of the positive bay area over the earth's surface during the course of bay. It is also noticed that the average current system of bay disturbance tends to shift eastward on the whole during its development and decay processes.
In the disturbance force of bays observed at Sitka, the influence of the auroral zone current is clearly seen. On the other hand, the disturbance force at Honolulu is so small in its magnitude that the bays' character is less systematic there compared with those in the middle latitude regions.
