W. A. Norton on the Corona in .Eclipses of the Sun. 7 



sist if we allow that tlie spots are merely the natural result of 

 the supposed discharges of the solar matter, prevailing for a 

 time at certain points of the photosphere ; or indeed if we grant 

 that they are in any way the result of these discharges visible 



(3.) In the wave propagation of the impulsive actions on tlie 

 ether of space, of the electric discharges to which we may ascribe 

 the material emanations from the photosphere, and in the elec- 

 tric and magnetic phenomena attendant upon the reception and 

 accumulation of the solar auroral matter in our atmosphere, we 

 have a plausible general explanation of the periodic and irregu- 

 lar disturbances of the magnetic condition of the earth, and of 

 their known physical relations to the sun's spots. This theory 

 of the origin of the diverse perturbations of terrestrial magnet- 

 ism I have elaborated, and followed out into a detailed discus- 

 sion of the variations of the different magnetic elements in 

 former Nos. of this Journal (viz : for March and July, 1855). 



We may add that it derives additional support from the gene- 

 ral result arrived at by Prof Chambers, in his discussion of the 

 " Nature of the Sun's Magnetic Action," viz : that "the mode in 

 which forces originating in the sun, influence the magnetic con- 

 dition of the earth, is not analogous to the action of a magnet 

 upon a mass of soft iron placed at a great distance from it, but 

 that these forces proceed from the sun in a form difierent from 

 that of magnetic force, and are converted into this latter foim 

 of force probably by their action upon the matter of the earth 

 or its atmosphere." " If this be admitted then we must conclude 

 that the perturbations of the earth's magnetic condition, as 

 evinced by the variations of the position and directive force 

 of the magnetic needle, must result either from some action 

 direct or indirect on the earth or its atmosphere, of some form 

 of matter emitted from the sun, or from a wave-action propa- 

 gated from the sun, or from both of these operative causes 

 combined. 



(4.) The streamers of the corona should have at different 

 points of the sun's photospheric surface different directions, 

 parallel to the diverse directions of the magnetic force of the 

 sun at this surface. These directions should be variously m- 

 cHned, in different heliographic latitudes, to the honzontal lines 

 at the points of the surface, and also to the plane of the sun's 

 equator ; like the dipping needle on the earth and the streamers 

 of a terrestrial aurora. In low latitudes the angles of inclina- 

 tion to the plane of the equator should be large, and the streamers 

 proceeding from corresponding points in the two hemispheres, 

 should converge and intersect in the plane of the equator, in 

 proportion as these correspondmg streamers proceed from 

 points more remote from the sun's equator, they will intersect 



