Secclii and Fay e on the Sun. — Observations by Chacornac. 273 



lateral tractions and currents in opposite directions arise. 

 ce When we examine the structure of the body below the pho- 

 tosphere, we find that its appearance of being pierced with 

 orifices, through which vapours are discharged, will account 

 for the shapes usually taken by spots and by simple pores. If 

 we follow the changes of the photospheric crystals deposited 

 or situated on the sloping branches of bridges, like those of 

 the 6th March spot, which plunge down into the dark cavity, 

 we observe the following facts. When, by reason of the move- 

 ments which transport large bodies into the depths of the 

 crater, they (the photospheric crystals) are carried into the 

 dark cavity — into the region of dissociation, if we may employ 

 the term — they seem to evaporate and dissipate, after they have 

 passed a certain limit, just as dappled atmospheric clouds behave 

 under the influence of a warm current/' 



From the preceding passages, which we have given as 

 literally as possible from M. Chacornac' s paper, the reader will 

 be prepared to learn that he regards the stratum below the 

 photosphere as pierced with innumerable little craters, or vent- 

 holes, through which vapours escape, and tear the luminous 

 envelope to a greater or less extent. He considers that the 

 region of most intense light does not extend beyond the 

 faculse ; that below them is a less luminous region — that of the 

 penumbras — in which the same actions take place, but with 

 less intensity. 



Speaking of the appearance of " lines of dislocation," 

 M. Chacornac observes, that at the beginning of the spots 

 which form the chief subject of his remarks, " all the vent- 

 holes (soupiraux) of the margin opened simultaneously, and 

 arranged themselves in an arc of a great circle. Some hours 

 later, some of these orifices were almost shut, and others con- 

 siderably enlarged ; but all were displaced so that the chain 

 of them presented a sinuous line, as if the entire mass sup- 

 porting the pasty outer layer (ecorce jodteux) was influenced 

 by currents varying in velocity according to their heliocen- 

 tric latitude. Thus, in spite of relative displacement, the 

 eruptive centres sensibly preserved their forms. Is not this 

 a proof that the orifice of the crater is pierced through a 

 medium of a certain consistence, and that the entire mass is 

 displaced V 



In another passage, M. Chacornac speaks of having con- 

 tinuously watched spots which joined to others of larger 

 dimensions by traversing a space of 1 7" in three hours, while 

 for three consecutive days he has seen a small spot remain 

 without change of form on the margin of a large opening. 

 There are thus periods during which the sun's outer layer 

 (ecorce) seems to be fused with a rapidity that manifests the 



