500 Mr. D. Vaughan on Luminous Meteors 



less lucid. I have already shown elsewhere how considerable 

 the effect of the absorbing power of the solar atmosphere is upon 

 the heat. By having recourse to a partition of the light into 

 two equal portions by means of a double-refracting prism, with 

 which a projection of the solar disc is thrown steadily on to white 

 paper, I have arrived at the following results : — 



1st. That the faculfe when near the edge are noways more bril- 

 liant than the centre of tbe disc, but that they appear to be so 

 only when contrasted with the lesser degree of brilliancy that the 

 disc has towards its margin, in consequeuce of the projection of 

 their summits above the lower portion of the absorbent atmo- 

 sphere. I saw, a few days prior to the eclipse in March last, 

 one of these faculfe of an enormous size, its length near the edge 

 being not less than 30°, with a breadth of 30". 



2nd. That the penumbra of a spot near the centre of the disc, 

 when observed with a low power, is not at all darker than the 

 parts close to the edge itself of the solar disc, and that its light 

 is about equal to half that of the lucid central portion. 



From this it appears evident that the influence of the lower 

 strata of the transparent atmosphere of the sun must exercise an 

 enormous power of absorption, and produce a great diminution 

 of light in the interior of the cavities of the photosphere. 



LVII. On Luminous Meteors and Temporary Stars. 

 By Daniel Vaughan, Esq. * 



IN my communications published in the Philosophical Maga- 

 zine for May and August 1858, I endeavoured to show that 

 several peculiai'ities of the variable stars and of the solar spots 

 give evident indications of the great office which a widely diffused 

 sether performs in maintaining the effulgence of all self-luminous 

 orbs. A study of the phaenomena of meteoric light furnishes 

 somewhat more satisfactory evidence on this subject. In obe- 

 dience to the power of gravity, the jetherial fluid of space must 

 be accumulated and condensed about the sun, while it also forms 

 less dense and extensive atmospheres for the planets. If (as 

 my theory supposes, or as we might infer from the principles of 

 chemistry) this subtle fluid requires a certain density or a definite 

 amount of compression to induce the chemical action which deve- 

 lopes heat and light, it can exhibit incessant heating and illumi- 

 nating energy only about the surface of immense spheres like 

 the sun. On the planets it must remain inactive, except in 

 places where it receives an extraordinary pressure from falling 

 meteorites; and accordingly, when these wandering masses 



* Communicated by the Author. 



