Physical Observations during a Total Solar Eclipse

Before the discovery of specfroscopy the programme was limited to the observation of the gradual progress of the moon across the sun's disc with the aid of telescope (with the usu41 darkening devices). [...] The observation of the corona the chromosphere and the prominences formed the chief items in the older eclipse programmes. [...] The slit is unnecessary because at the moment or totality the source of light is the An crescent-like part of the solar chromosphere intercepten by the moon's diso. [...] The predicted deflection js 1'14 -1-i7 seconds' of arc where r " is the serail-diameter of the sun R is the angular distance of the star from the centre of the sun. [...] Hydrogen gives four lines in the visible spectrum the red line A = 6583 corresponding to the C-line of Fraunhofer ; the green line A = 4861 the F-line of Fraunhofer the blue line A = 4340 f of Fraunhofer the viqjet line A = 41011 the h of Fraunhofer.