ASTRONOMY. 19 



may be were in such quantity and condition, and rose so 

 high above the solar surface that their lines were conspicu- 

 ous in the coronal spectrum, and attracted the attention of 

 observers far more forcibly than the feeble continuous spec- 

 trum of the light emitted from, and reflected by, the minute 

 solid or liquid particles which also constitute an essential 

 element of the corona. At present the condition is reversed. 

 The gases are either too small in quantity or too cool to be 

 conspicuous. The lesson, and it is an important one, is sim- 

 ply, as has been said, that, to a certain extent, the corona 

 sympathizes with the sun-spots. 



" It certainly looks probable, also, that while the gaseous 

 elements of the corona are strictly solar, the non -gaseous 

 matter the coronal dust or haze is of extraneous and very 

 likely meteoric origin. At any rate, the extent of the corona 

 was certainly not less than on former occasions, whatever 

 may have been the case with its brightness. In fact, it has 

 never been traced quite so far from the sun before, as this 

 time by Langley and Newcomb, who followed it out for 6 

 along the ecliptic, a success partly, of course, due to the 

 clearness of the air at their elevated stations. Now, this is 

 quite consistent with the theory that meteor streams furnish 

 the hazy matter of the coronal envelope, since, so far as we 

 can judge, they have nothing to do with sun-spots. 



" A very interesting problem relates to the effect of solar 

 forces upon this meteoric matter, if such it really be, and the 

 material for the study is furnished in rich abundance by the 

 numerous drawings made by Langley, Abbe, Penrose, Boss, 

 and others, and by the photographs, which in excellence and 

 number excel those obtained on any previous occasion. 

 Among; the best which we have seen are the mao*nificent se- 

 ries made by Rogers at La Junta, those of Draper at Raw- 

 lins, and those of the Princeton party at Denver; undoubt- 

 edly there are others of at least equal excellence. 



"To sum up: the eclipse of 1878 has probably added a 

 new planet to the system, and has rendered it likely that the 

 unknown cause, whatever it may be, which produces the pe- 

 riodical sun-spots at intervals of about eleven years, also af- 

 fects the coronal atmosphere of the sun. 



"The result of the late eclipse goes to show such a peri- 

 odical change in the state of the solar atmosphere as might 



