ECLIPSE OBSERVATIONS. 263 



pressed by observers of the more recent eclipses. But these rela- 

 tions are not always evident as will be shown by extracts from 

 published observations of eminent observers and students of eclipse 

 phenomena. It is probably true that hoods and envelopes over the 

 prominences are generally present but are greatly reduced in in- 

 tensity or may even be absent for a short time near sun-spot minima 

 and it is also probably true that such detail and complex structure in 

 the inner corona are generally conspicuous at times of greater solar 

 activity. 



From an extensive examination and careful study of many 

 photographs of the corona beginning with the eclipse of 1851 and 

 continuing with the later eclipses of i860, 1870, 1871, 1875, 1878, 

 1882, 1883 and 1885, an eminent authority on eclipse photographs 

 writes : " There is no sign of any connection between the coronal 

 rays and the solar prominences." It would seem, however, that the 

 present trend of the interpretation of observational results is that 

 the prominences generally do affect to a marked degree coronal 

 structure in their vicinity. 



The complex coronal structure, arches, etc., of the eclipses of 

 1871, 1883, 1893, 1905 and 1918 occurring at or near times of sun- 

 spot maxima, and the almost complete absence of such intricate and 

 complicated detail of the lower regions of the conona of the eclipses 

 occurring at or near the minima of sun-spot activity in 1878, 1889 

 and 1900 may be mentioned in this connection. The eclipses at the 

 minimum epochs were so fully and so successfully observed that it 

 is difficult to believe that such structure could have been overlooked. 

 The reports for 1900 by Hale, Langley, Newall, Wesley and others 

 are especially complete in this respect as specific mention is made 

 with reference to search for such detail. It also appears from the 

 observational results that the complex detail in question is present 

 in varying degrees for eclipses observed preceding or following 

 minima of solar activity. The eclipses of 1896 and 1898 are good 

 examples of eclipses that fall between a maximum and minimum. 



The question of changes taking place in detail in the corona 

 in the interval between observations made at different stations is 

 one of great interest and we are not aware that a definite answer 



