Analysis of geomagnetic effect of previous 5 solar eclipses occurring in China during past 50 years

In this paper results and analysis of geomagnetic observations during previous 5 solar eclipses occurred in China are summarized. They are solar eclipses: No. 1, on 19 June 1936 in Heilongjiang of NE China; No. 2, on 21 September 1941 in Fujian; No. 3, on 19 April 1958 in Hainandao; No. 4, on 22 September 1968 in Xinjiang; and No. 5, on 16 February 1980 in Yunnan of SW China. The authors took part in the last 2 expeditions and joint programmes in the track of totality.The methods of evaluation for eclipse effects on the geomagnetic field are briefly described both for the quiet and disturbed days. The discussion of these data is made with reference to Chapman's theoretical consideration on optical eclipse effect, together with the quiet-day overhead current systems in the upper atmosphere. We conclude that optical eclipse effects are easily observable under favourable conditions, and further observations are essential to establish the yet unknown effects due to corpuscular eclipses.