THE PHILOSOPHY OF THE RADIOMETER. 63 



around the sun would be broken up, sifted, and sorted into 

 different orbits, according to their diameters, if this super- 

 ficial repulsion operated against gravitation without any 

 compensating agency. Gravitation would be opposed in 

 various degrees, neutralized, and, in the case of cosmic dust, 

 even reversed. Comets presenting so large a surface in 

 proportion to their mass would either be driven away alto- 

 gether or forced to move in orbits utterly disobedient to 

 present calculations. This would occur if the inter-planet- 

 ary spaces were as nearly vacuous as the torsion instrument 

 with which Mr. Crookes made his measurements. 



Kegarding the properties of our atmosphere only in the 

 light of experimental data, irrespective of imaginary mole- 

 cules, and their supposed gyrations or oscillations, we see 

 at once that an inter-planetary or inter-stellar vacuum must 

 act like a Sprengel pump upon our atmosphere, upon the 

 atmosphere of other planets, and upon those of the sun 

 and the stars, and would continue such action until an 

 equilibrium between the repulsive energy of the gas and the 

 gravitation of the solid orbs had been established. Atmos- 

 pheric matter would thus be universally diffused, with 

 special accumlations around solid orbs, varying in quantity 

 with their respective gravitating energy. Such a universal 

 atmosphere would accelerate orbital motion, and this ac- 

 celeration would vary with the surface of bodies. Its action 

 being thus exactly opposed to that of radiant repulsion, it 

 must, at a certain density, exactly neutralize it. That it 

 does this is evident from the obedience of all the elements 

 of the solar system to the calculated action of gravitation; 

 and thus Mr. Crookes'qgjesearches not only confirm the idea 

 of universal atmospheric diffusion, but they afford a means 

 by which we may ultimately measure the actual density of 

 the universal atmosphere. If, as I have endeavored to show 

 in my essay on "The Fuel of the Sun," the initial radiant 

 energy of every star depends upon its mass, and its conse- 

 quent condensation of atmospheric matter, the density of 

 inter-planetary atmosphere sufficient to neutralize the radi- 

 ant mechanical energy of our sun may be the same as is 

 demanded to perform the same function for all the stars of 



