408 SCIENTIFIC WRITINGS. 



solar potential admissible. The objection of the astro- 

 nomers that interplanetary space cannot contain the 

 smallest quantity of matter, because then the period 

 of the planets would be increased, I sought to refute 

 by the consideration that the matter itself, expelled 

 from the sun, must rotate round the sun with plane- 

 tary velocity, that it could not therefore impede the 

 course of the planets. I also supported my brother's 

 view that the solar light arises from the burning solar 



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mass in its ascension, although I could only to a cer- 

 tain extent assent to his view that the combustible 

 atmosphere resting on a fluid or solid solar surface, 

 which is flung off in the burnt state and then again 

 dissociated by the sunlight in space, and in this state 

 again attracted by the sun, was the cause of the solar 

 rays. I could only assent to it so far as the participation 

 of the whole gaseous mass of the sun in the combustion 

 was concerned, and could assign to the flung-off mass 

 only a secondary importance in the thermal economy 

 of the sun, but on the other hand considered it decisive 

 as regards the question of its electrical charge. 



Ritter's admirable and still insufficiently appreciated 

 works remove all doubts as to the sun's gaseous state, 

 with which the existence of a special solar atmosphere 

 is incompatible. We must therefore assume that the 

 whole solar mass is undergoing a continuous process 

 of combustion, but which can only actually take place 

 in the outermost layer of the body of the sun, where 

 the solar gas is already so far cooled by expansion 

 that chemical combinations can be formed. These 



