666 TEE POPULAR SCIENCE MONTHLY. 



very unlike those through which the earth herself passes. The meteor 

 systems required by the theory must be much denser and much more 

 brightly illuminated than the August and November systems. To say 

 they must be much more brightly illuminated is equivalent to saying 

 that they must be much nearer the sun. And in this we see an escape 

 from another difficulty. Meteor systems very near the sun would be 

 far more likely to appear as streamers extending radially from him 

 than systems at a great distance from him. A distant system might, 

 by a mere chance, so appear. For instance, if a total eclipse of the 

 sun had occurred on or about May 10, 1865, the November meteor sys- 

 tem (whose richest part was then crossing the earth's track at the 

 point she occupies on November 13th) would have appeared, if dis- 

 cernible at all, as a streak athwart the sun's place in the sky, and there- 

 fore forming two rays on opposite sides of him, somewhat like 2 and 5 

 in our figure. Sixteen years or so earlier or later the November system 

 would present a similar appearance, only very much fainter, on account 

 of greatly increased distance, during a total eclipse occurring on or 

 about November 13th. At no other time in the year except November 

 13th and May 10th, or about these dates, could the November system 

 present such an appearance. But a sj'stem traveling close to the sun, 

 and not far from the plane near which all the planets travel, Avould 

 present at all times nearly the appearance of a pair of rays like 2 and 

 5 of our figure. On this account, therefore, as well as on account of 

 the greater brightness with which such meteor systems would be illu- 

 minated, we must prefer the theory that the systems to which the 

 coronal rays are due travel near to the sun. 



Yet, even as thus presented, the meteor theory alone seems inade- 

 quate to explain the coronal streamers. There is an enormous mass of 

 evidence showing that meteor systems are most richly strewed through- 

 out a region around the sun, extending nearly to the distance of the 

 planet Mercury ; but there is also abundant reason for believing that 

 these multitudinous systems would present an appearance very different 

 from that depicted in Professor Abbe's view of the coronal streamers. 

 We want something quite distinct from the theory of a mere aggrega- 

 tion of meteors to account for these rays, whether pointed or fan-shaped, 

 extending directly from the sun. The aggregation of meteors might 

 present the appearance of a luminous cloud around the place of the 

 eclipsed sun. This cloud might be to some degree radiated, because 

 each meteor system would have a course carrying it either directly 

 athwart the sun's place on the sky, or nearly so. But there would be 

 nothing like those sharply defined streamers extending separately from 

 the sun to distances of ten or twelve sun-breadths. Sir George Airy, 

 describing the appearance of the corona during the eclipse of 1851, pic- 

 tures just such a cloud as we should expect to result from the aggrega- 

 tion of meteors. " Its color," he said, " was white, or resembling that 

 of Venus ; there was no flickering or unsteadiness ; it was not separated 



