402 
MR. J. EVERSHED ON 4VAVE-LENGTH DETERMINATIONS, ETC., 
This result is in satisfactory agreement with the value found by Mr. Fowler 
on the plates obtained by Sir Norman Lockyer. The difference between the two 
measures above is due to the opposite displacement of the line in the photographs 
taken at second and third contacts, the point measured being situated about 
2' above the moon’s limb. This apparent displacement affects all lines of a 
diffuse character where the moon’s limb is not well defined. 
The three corona lines shown on these jolates are therefore— 
1. 3388. 
2. Near H (on less refrangible side). 
3. 5303-3. 
The ultra-violet line is similar to the green line in distribution round the limb, and 
is probably due to the same substance, whilst the line near H differs from the others 
in showing no maxima of intensity, the substance producing it being evenly dis- 
ti’ibuted on the west limb. 
There is no trace whatever of any other coronal line on any of the plates. 
Summary oe Kesults. 
The principal results obtained from the study of these photographs are stated 
briefly in the following joaragraphs :— 
1. Practically every strong dark line in the solar spectrum is j^resent as a bright 
line in the Hash spectrum. 
2. Almost all the flash-spectrum lines (excepting those due to hydrogen and 
helium) coincide with dark lines in the solar spectrum. 
3. The relative intensities of the lines of any one element in the flash spectrum are 
})ractically the same as those of the same element in the solar spectrum. 
4. The relative intensities between groups of lines belonging to different elements 
are widely difterent in the flash and in the solar spectrum. 
5. The apparent intensity of the radiation from any element in the lower chromo- 
s})here is determined by the extent to which that element is diffused above the 
photosphere ; and the real relative intensities between the difterent elements cannot 
be judged in photographs of tlie flash spectrum. 
6. Tlie flash spectrum may be considered to represent the upper more extensively 
diftused portion of a stratum of gas which, by its absorption, gives the Fraunhofer 
dark-line spectrum. 
7. Nearly all of the known metals having atomic weights less than 60 are repre¬ 
sented in these spectra, and no element having a higher atomic weight than 92 is 
certainly represented. 
8. All the strong lines in the flash spectrum can be identified with known elements, 
and the small proi^ortion of unidentified lines are weak lines. 
