ASTKONOMY. 23 



The party under Professor S. Newcomb was stationed at 

 Separation, Wyoming. 



This party observed contacts and exposed a large number 

 of (dry) photographic plates in a photoheliograph. When 

 these plates came to be developed, no image of the sun was 

 seen. The plates were certainly sensitive, and the cause of 

 the failure is unknown. 



Commander W.T. Sampson, U.S.N"., who observed the eclipse 

 at Separation with Professor Newconib, describes briefly his 

 examination of the spectrum of the corona in The American 

 Journal of Science for November. The result he sums up as 

 follows : " The conclusion forces itself upon my mind that 

 the light of the corona is not all reflected light. Several 

 considerations lead to this conclusion. Until this eclipse, no 

 observer has ever seen the dark lines in the spectrum of the 

 corona except M. Janssen, who reported dark lines, notably 

 D, in 1871, but much more difficult to see than the bright 

 lines. Several observers during the recent eclipse failed to 

 see the dark lines, though they looked for them carefully. 

 While I do not question the results of observers who report 

 the presence of dark lines, I think all the observations taken 

 together show that the continuous spectrum of the corona is 

 not the spectrum of the sun. Aside from this, Professor Ar- 

 thur W. Wright made measurements of the polarization of 

 the light of the corona the first time, I think, it has been at- 

 tempted and has found the polarization to be but a small 

 percentage of the whole light emitted. Although all re- 

 flected light does not reach us as polarized light, yet I think 

 the small percentage of polarization, taken with the faint- 

 ness of the dark lines, indicates that the corona is to a 

 considerable extent self-luminous. The meteoric dust not 

 only reflects the sun's light, but it is continually shower- 

 ing upon the sun, and in its passage through its atmosphere 

 is rendered incandescent. No photographs of the spec- 

 trum of the corona can probably throw any light upon the 

 matter." 



A party consisting of Professors S. P. and J. W. Langley 

 occupied the summit of Pike's Peak. They were engaged 

 in photometric determinations of the light of the coronn, 

 etc., and secured valuable drawings ; and Professor S. P. 

 Langley was able to trace the corona for several degrees on 



