476 
MK. J. EVEESHED ON THE SOLvVK ECLIPSE OF 1900, MAY 28. 
Avj^rage Intensity of the Principal Enhanced Lines of Fe and Ti. 
Ti (23 lines). 
Fe (14 lines). 
In latitude - 74°/75° (fro™ No. 9 and 13 spectra)*. . . 
,, -41° (from No. 11 spectrum). 
16-3 
18-6 
18-4 
14-6 
It will be seen from this that while the Ti lines appear to be slightly weaker in 
bigli latitudes than in mid-latitndes, the Fe lines give just the opposite result; so 
that by taking both elements together there is found to be practically no difference 
at all. The small differences indicated for the lines of each element alone, may safely 
be put down to the uncertainties of the original estimates of intensity. 
It is to be inferied, tlierefore, that the enhanced lines are of the same intensity in 
all latitudes, and that the general character of the flash spectrum remains unaltered 
in passing from the equator to the poles. This does not, however, preclude the 
possiljility that the flash stratum is shallower in the ])olar regions than near the 
equator. 
An interesting subject for future inquiry would be as to whether the flash 
spectrum undergoes any modifications such as an increase or decrease of depth of the 
layer or changes in the intensity of the enhanced lines at different epochs in the sun¬ 
spot period. If the chromos|)here is really of an eruptive character one might 
expect, at times of maximum spot activity, when also the metallic eruptions are most 
frequent, that the flash spectrum region would extend to greater altitudes in the 
chromosphere and that the enhanced lines would be relatively brighter than during 
the quiet periods of minimum. 
The evidence so far obtained is, it is true, against any marked changes occurring, 
I have compared the spectrum obtained by Shackleton in 1896 with those herein 
discussed and with others olflained in 1898 and 1901, but without detecting any 
certain changes in the intensities of the lines. The flash appears, in fact, to be of as 
constant and unchanging a character as is the Fraunhofer spectrum, which is only 
what would naturally be expected, seeing that it ap|)ears to be in the main the 
reversal of that spectrum. 
Suiiiinarij of Conclusions. 
In a general way the conclusions arrived at from the discussion of the spectra 
obtained in 1898 are amply confirmed and extended by the present results. 
It is now shown that every strong dark line of the solar spectrum exceeding 
Howland’s intensity 7 is found in these spectra as a bright line; and the great 
* The observed intensities of the high latitude spectra have been multiplied by the factor 1‘81, this 
numl)er representing tlie l atio of intensities between these two spectra taken together and No. 11 spectrum, 
when all the lines between A 39 and A 50 arc compared. 
