The electric characterization of days at the Huancayo Magnetic Observatory for the 12 years 1925–1936

Abstract

Observations of the atmospheric potential‐gradient were begun by the Carnegie Institution of Washington at the Huancayo Magnetic Observatory, in Peru, in 1924. A photographically‐recording apparatus was installed at that time and has been in practically continuous operation up to the present. The data thus accumulated are now being tabulated for publication and will appear shortly, together with complete descriptions of the apparatus, its location, and particulars of the surrounding countryside.At the inauguration of the observing‐program it was decided that the electric characterization of days as used by the British Meteorological Office at Kew Observatory should be adopted. This system has recently been described in detail by F. J. W. Whipple1 and need be mentioned only briefly here. There are three character‐figures, 0, 1, and 2. “0” denotes the absence of negative potential in any 24‐hour period beginning at midnight, “1” indicates the existence of negative potential at one or more times during the 24‐hour period but with a total duration of less than three hours, and “2” indicates the existence of negative potential for a total duration of three hours or more.