32 THE PROGRESS AND SPIRIT OP 



circular and elliptic polarisation have still further confirmed 

 and defined the analogy in question. 



The evidences connecting electricity and magnetism, as 

 forces, with the Sun and other bodies of our system, are dif- 

 ferent and inferior to those which establish the relations of 

 light. Yet are they now continually becoming more nume- 

 rous and significant. Whoever has seen the star of pure 

 and intense light which bursts forth on the approach of the 

 charcoal points completing the circle of a voltaic battery, 

 or the flood of light thence poured by reflection over wide and 

 distant spaces, cannot but suspect that the new 6 fountain ' 

 thus opened to the eyes of men (and certainly not destined 

 to remain an idle and valueless gift of science) may be the 

 same in source and qualities as that higher fountain which 

 diffuses light and heat over the whole planetary system. Sir 

 J. Herschel, who ever makes his highest speculations sub- 

 ordinate to cautious induction, has assigned strong reasons 

 for believing the Sun to be in a constantly excited electrical 

 state. The singular phenomena of the tails of comets, he 

 considers as only to be explained by supposing a repulsive 

 force acting from the central body, which force electricity 

 alone could furnish. ' The sun electrically charged would 

 induce opposite states in the two hemispheres of day and night 

 on the earth,' is the expression he applies to the effect of such 

 solar condition upon our own globe.* And if we suppose, as 

 may fairly be done, variations in the intensity of this elec- 

 trical state, we acquire a probable cause for many periodical 

 or secular variations which have hitherto embarrassed science. 

 We allude here especially to changes in the intensity, decli- 

 nation, and inclination of the magnetic force that extraor- 



* These passages will be found in Sir J. Herschel' s volume on the ' Nebulae 

 and Double Stars of the Southern Hemisphere;' a volume in which the 

 tabular results of his vast labours of observation are intermingled with some of 

 the highest speculations to which the human mind has yet legitimately reached. 



