A GREAT SOLAR OUTBURST. 213 



the corona. The erupted hydrogen reached a certain 

 enormous altitude, and there (so far as the extrusion 

 of matter from the sun was concerned) the work of 

 the solar eruption came to an end. But the spectrum 

 of the jet prominences indicates the presence of 

 several other elements amongst others, several metallic 

 elements in the state of vapour. Now, it is highly 

 probable that at a very early stage of the upward 

 motion a large proportion of the metallic vapour would 

 condense into the liquid form ; and if so, such liquid 

 metallic matter would thenceforward meet with far 

 less resistance, and so would travel to a far greater 

 distance than the hydrogen. But without insisting 

 on this point, we may yet feel assured that under 

 similar conditions of temperature and pressure the 

 vapours of the metallic elements far exceed hydrogen 

 in density. Thus they would from the very beginning 

 of their upward course be exposed to a much less 

 effective retarding influence. They would, therefore, 

 retain a much greater proportion of the velocity 

 primarily imparted to the whole body of erupted 

 matter; nor is it by any means an unreasonable or 

 unlikely supposition that at a height of 100,000 miles 

 some of these constituents of the erupted matter would 

 be travelling twice as rapidly upwards as the hydrogen 

 watched by Professor Young. So far, indeed, is this 

 view from being unlikely that it is difficult to entertain 

 any other opinion. Yet, on this view, the matter 

 referred to would be travelling at a rate greatly ex- 

 ceeding 400 miles per second ; and a much smaller 



