390 
^IR. J. EVEESHED ON WAVE-LENGTH DETERMINATIONS, ETC. 
inner corona ; it is most intense at position angles 60° to 78° and 95° to 105°. On the 
west side it can be traced at about position angle 250°, but is extremely faint here. 
No trace of any true corona line can be made out in the blue or violet part of the 
spectrum, but there is a fairly distinct impression of a line near the end of the plate 
at X 3388, where faint maxima of intensity are indicated on the east limb at the same 
position angles as the maxima of the green line. 
The chromosphere in this negative is represented by the lines H and K only, which 
form arcs extending over the western limb (P.A. 182°-289°). The prominence C 
gives the princijral hydrogen, helium, and titanium, lines in addition to H and K. 
Spectrum No. 6 (Plate 11, fig. 4).—-The exjjosure in this case was of 10 seconds’ 
duration, beginning about 2 seconds after closing No. 5. 
The chromosphere arcs have reappeared in the hydrogen and helium lines on the 
west limb, and the former can be traced to Htt. The three strongest titanium lines 
are also visible, extending over an arc of 60°. The prominence C shows the streak of 
continuous spectrum starting at \ 3668 and extending as a fine thread far into the 
ultra-violet. 
The green corona line is faintly impressed both on the east and west limbs, but no 
other corona line can be made out with any certainty. There is, however, a doubtful 
impression of a line extending pretty uniformly over the west limb at a point in the 
spectrum a little less refrangible than H (X 398/399). It cannot be traced at all on 
the east limb, at the points where the green line is most intense, and if it is a real 
corona line, the substance producing it is evidently not the same as that which gives 
the green line. 
Spectrum No. 7 (Plate 11, fig. 5).—The exposure of 20 seconds’ duration was 
started immediately after the last and ended only 3 or 4 seconds before the photo¬ 
sphere appeared. 
In the chromospliere spectrum Ha is well shown, and in the ultra-violet the 
hydrogen lines can be clearly traced to Hw. Many of the stronger flash-spectrum 
lines are visible along the central portion of the photograph extending over arcs of 
from 40° to 60°. The wave-lengths deduced from measures of these lines are given 
in Table I., and in the region between X340 and X 360, where the focus is good, the 
results are as accurate as those obtained from No. 3 spectrum. 
A conspicuous feature in this photograph is the shaded band of continuous 
spectrum in which the more refrangible lines of the flash spectrum are immersed. It 
is absent in the region less refrangible than X 3668, and corresponds to the fine 
streak or tail which the prominence C shows in all the pliotographs obtained during 
totality. 
The green corona line is better defined in this photograph than in any of the 
others. The positions of maximum intensity correspond precisely with the bands of 
continuous spectrum due to the Inlghtest regions of the inner corona. The position 
angles measui'ed on tins 2 )late are as follows :— 
