OF SPECTRA AT THE SOLAR ECLIPSE OF JANUARY 22, 1898. 
403 
9. The wave-lengths of the hydrogen lines in the ultra-violet agree closely with 
those derived from Balmer’s formula. 
10. The prominences and lower chromosphere emit a strong continuous spectrum 
in the ultra-violet, beginning near the limit of the hydrogen lines and extending 
indefinitely in the more refrangible region. 
11. The ultra-violet hydrogen lines increase in intensity towards the photosphere, 
but remain narrow lines in the flash-spectrum layer. 
12. Some of the helium lines decrease in intensity towards the photosphere, others 
increase. 
In conclusion, I have to acknowledge my indebtedness to Dr. Bambaut for much 
valuable help and advice in the preparation of this paper, and lor the kind interest he 
has taken in the work throughout. 
I have also to acknowledge the great assistance rendered to me by Mr. L. E. 
Jewell, of the Johns Hopkins University, who made a careful and exhaustive study 
of some positive copies of my plates. 
In identifying the lines given in the tables, I have been guided almost entirely by 
his results; and I am also indebted to him for supplying me with revised values of 
many of the solar lines given in the last column of each table. 
Table I.— Flash Spectrum Wave-lengths compared with the Dark Lines of the Solar 
Spectrum. 
In this table the wave-lengths deduced from the measures of No. 3 and No. 7 
sjDectra are entered in the first two columns. The third column gives the photographic 
intensities for No. 3 spectrum. These were estimated on a scale ranging from 1 to 10 ; 
1 representing very weak lines, and 10 representing the strongest lines in the spectrum. 
Very faint traces of lines difficult to measure are designated 0 in this column. 
In column 5 the wave-lengths of the solar lines are given with which the bright 
lines have been identified with a greater or less degree of probability. The intensi¬ 
ties as given by Howland are entered in column 6, and the element corresponding 
to the solar line in the last column. The wave-lengths of the helium lines are ^^laced 
within brackets ; they are taken from the tables of Bun C4E and Paschen. 
The columns 5, 6, and 7 are taken from Bowland’s tables of solar lines 
published in the ‘ Astro-Physical Journal ’ for 1895, 1896, and 1897, and supplemented 
by more recent determinations supplied to me by Mr. J ewell. In a few instances the 
identifications and intensities will be found to differ from those given in the tables. 
In column 4 an (S) means a sharply defined line, well identified, and suitable to be 
taken as a standard line in wavedength determinations. A (?) in this column 
indicates that the identification with the solar line is extremely doubtful. 
In the last column a ? means that the element in question has not been identified 
with certainty with the solar line. 
3 E 2 
