The Evolution of the Sciences 



in one direction, at least at the same time and in 

 the same region. Elsewhere it towers above 

 the general level in monstrous heaps called 

 protuberances. 



These protuberances take the most diverse 

 forms, and an . attempt has been made to dis- 

 tinguish them by the names of heaps, jets, and 

 plumes ; but what strikes the observer most 

 forcibly is the ceaseless agitation stirring the 

 entire gaseous mass and projecting it, during 

 movements of violent eruption, to a height of 

 several hundred thousand kilometres, at speeds 

 reaching, and even exceeding, two hundred kilo- 

 metres per second. 



The following observation of Secchi may 

 serve as an example: 



" On October the i6th 1871, at ten minutes 

 past nine o'clock, the western part of the sun 

 did not present any remarkable feature. At 

 9.30 a very intense conical flame became visible 

 towards the west at 85 from the pole; near by, 

 at a distance of about 5, was a large and diffuse 

 cumulus; at 9.36 the height and width of the 

 flame had doubled, and this cumulus appeared 



to have been absorbed by it. At 9.43 all had 



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