46 LIGHT SCIENCE FOR LEISURE HOURS. 



half times that obtained by means of Parker's great 

 lens, which melted such refractory substances as corne- 

 lian, agate, and rock-crystal. Meteors so close as this 

 to the sun would be so intensely heated that their in- 

 herent light would be even more brilliant than that 

 which they would be capable of reflecting. Many 

 would even be vaporised as they rushed past the point 

 of their nearest approach to the solar orb. We see then 

 that, quite apart from the information which a solar 

 eclipse affords us, we really have just reason for pro- 

 nouncing with considerable confidence that something 

 very like what the corona appears to be must exist in 

 the sun's neighbourhood. 



Now it is well worth noticing that if we suppose 

 the corona really to be caused by the illuminated 

 meteoric systems, we get rid at once of that difficulty 

 which spectroscopic analysis opposed to the theory that 

 the corona is a solar atmosphere. These swiftly rushing 

 meteors would no more tend to increase the pressure 

 at the base of the solar atmosphere than the moon, 

 circling as she does round the earth, tends to increase 

 our own atmospheric pressure. 



It happens, too, that such evidence as has hitherto 

 been given by the spectroscope respecting the actual 

 constitution of the corona corresponds very satisfactorily 

 with the conclusions above deduced. I do not enter 

 here into a very particular account of that evidence 

 first, because the observations made by different astro- 

 nomers have not yet been brought into complete 

 accordance ; and secondly, because it is confidently 



