THE SOLAR ECLIPSE OF 1871. 101 



playing a multitude of bright stripes exactly where the 

 black lines of the ordinary solar spectrum appear. 



Secchi announced that these bright lines were to be seen 

 under favorable circumstances, when, by skillful manage- 

 ment, the rays from the edge of the sun were so caught by 

 the slit of the spectroscope as to exhibit only the spectrum 

 of the superficial layer of the sun's bright surface. This 

 was disputed at the time by Mr. Lockyer, who, I suspect, 

 omitted to consider the atmospheric difficulties under which 

 English astronomers work, and the fact that the atmos- 

 phere of Italy is exceptionally favorable for delicate as- 

 tronomical observation. 



If he had fairly considered this I think he would agree 

 with me in concluding that an observation of this kind, 

 avowedly made with great difficulty and questionable dis- 

 tinctness by so skillful a spectroscopic observer as Father 

 Secchi, could not possibly be seen by any human eyes 

 through a London atmosphere. 



Subsequently Professor Young startled the astronomical 

 world by the announcement that, at the moment when the 

 thinnest perceptible thread of the sun's edge was alone dis- 

 played during the eclipse which he observed, the whole of 

 the dark lines of the solar spectrum flashed out as bright 

 stripes in a most unmistakable manner. This observation 

 is now fully confirmed. The first telegrams from Mr. Pog- 

 son, the Government astronomer of Madras, and from Col- 

 onel Tennant, both announce this most positively, Colonel 

 Tennant's words being, " the reversion of the lines fully 

 confirmed." A similar result was obtained by some, but 

 not by all, of the Ceylon observers. 



To understand this clearly, we must consider the fact 

 that what appears to us as the outline of aflat disc is really 

 that part of the sun which we see by looking horizontally 

 athwart his rotundity, just as we look at the ocean surface 

 of our own earth when we stand upon the shore and see its 

 horizon outline. When the moon obscures all but the last 

 film of this solar edge, we "See only the surface of the sup- 

 posed gaseous orb, just that portion of the blazing gases 

 which are not greatly compressed by those above them, and 

 which accordingly should, if they consist of the vapors or 



