Magnetic declination at kew observatory, 1890-1900

The paper deals with the phenomena exhibited by the magnetic declination at Kew from 1890 to 1900. The magnetograph curves have been measured on every day of this period, whether disturbed or undisturbed, and the data from days of the different species are contrasted. Diurnal inequalities are got out for ordinary days, excluding those of large disturbance, and separately for the highly disturbed days, and the differences between these, and the points wherein they differ from the corresponding inequalities fromquiet days, are investigated. The disturbed days show a well-marked regular diurnal variation, which differs in many notable respects from that observed on ordinary days.