168 Chacornac on the Volcanoes of the Sun. 



with tlie narrow orifice downwards, and the forms of streams 

 and ripples (sillons) of flocculent matter always indicate a 

 descent of the upper layers into the regions below. 



When a funnel-shaped gulf is formed by the sinking down 

 of the atmospheric strata, there is a disturbance in the equili- 

 brium of the flocculent masses, precipitation of adjacent layers 

 into the orifice, and accumulation of vaporous matter at this 

 part of the atmosphere, as is shown by the faculae heaped up 

 in the vicinity of a dark cavity. It seems as if this affluence 

 of a vaporous fluid gave rise to a heaping up (bourrelet) of 

 atmospheric masses round a dark spot. At the base of these 

 mountains a fusion takes place, and when the changes are 

 very rapid, lines of dislocation are observed, circumscribing 

 the annular mountains, and rendering them top-heavy, so that 

 they fall and give rise to a penumbra. 



M. Chacornac describes a case in which a small spot ap- 

 proached a large one and fell into its penumbra, without 

 lessening it or occasioning any other change than making a 

 new orifice in its perimeter; and he likens the currents of 

 photospheric matter to the cascades of Niagara, in which the 

 form is preserved. After the examination of this fact, he affirms 

 it to be impossible to regard the spots as occurring in a liquid 

 medium, for he says we should ask how such masses of liquid 

 could be volatilized without occasioning an immense confla- 

 gration when they were converted into gas ? Immense photo- 

 spheric clouds dissolve in a few hours, though their volume 

 may be greater than that of the earth. 



M. Chacornac considers that the hypothesis of solar vol- 

 canoes arising in a liquid medium cannot be maintained, as 

 the phenomena can only be explained on the supposition of 

 rapid currents occasioned by the formation of a vacuum. A 

 central body in a liquid state would not, he thinks, be in con- 

 tradiction to the general phenomena exhibited by the sun. It 

 would be the source from which emanates that cloudy mass 

 which constitutes the solar atmosphere of which the limiting 

 layer is in a state of lively incandescence. According to this 

 hypothesis the temperature decreases from the circumference 

 to the centre, as the law of densities augmenting in the same 

 direction demands. Varying degrees of heat and density in 

 different strata, and the effect of the sun's rotation, would 

 give rise to currents such as are seen in the trade winds, in 

 the belts of Jupiter, and in the motions of sun spots, provided 

 that the atmosphere is situated upon a solid body. 



M. Chacornac thinks that the sun may consist of a 

 central liquid covered with a solid pellicle, and surrounded by 

 an atmosphere composed of several layers, which in their 

 normal condition appear in contact and united. The pellicle, 



