338 
CAPTATX L. DARWIX, DR. A. SCHUSTER, AHD MR. E. W. MAUXDER 
If we compare together the measurements taken during different eclipses, we find 
that the agreements are good, especially those taken with Spectroscope II. in 1886 
compared with those taken in 1883. The resolving powers in the two cases were about 
equal, and double that used in 1882. Nearly all lines found in 1883 have a repre¬ 
sentation of intensity (3), or above in 1886. Our data as yet are insufficient to judge 
whether there is any great difference in the spectra during different eclipses. The slit in 
1883 was radial; that in 1886 was placed tangential to the Sun’s limb, and this would 
account for some difference in the relative intensities of lines, for some of the lines in 
the radial spectroscope fade undoubtedly more rapidly as we go outwards in the 
corona than others. A number of lines are wide in those parts of the corona which 
show the continuous spectrum, strongly thinning out where that spectrum is weak. 
Nevertheless, I cannot help thinking that, if the line 4232’8 had been as strongly 
marked in previous eclipses as it has been in this, it would have attracted special 
notice. On the other hand, a line 4015, which was marked strong in 1882, and 
which was present in 1883, does not appear in our photographs. There is, therefore, 
some ground to believe that the spectrum of the corona differs much on different 
occasions, although we want further evidence to settle the point definitely. 
I have collected in the following Table the most persistent lines in the spectrum of 
the corona; that is to say, those which appear in all three eclipses. 
1886. 
1883. 
1882. 
4056-7 
4057 
4056 
4084-2 
4085 
4085 
4169-7 
4169 
4168 
4195-0 
4195 
4192 
4211-8 
4213 
4212 
4232-8 
4227 
4224 
4253-6 
4255 
4252 
4372-2 
4370 
4370 
4402-2 
4401 
4400 
4474-4 
4473 
4473 
4498-5 I 
4505-4/ 
4501 
4501 (double) 
4725 
4718 
4721 
It seems curious that the discrepancy is greatest for our strongest corona line. 
The line 4227 in 1883 may have been the calcium line. That our corona line is less 
refrangible is proved not only by the measurements which are given above in detail, 
but can be shown by simply placing the corona spectrum film to film against the 
reference spectrum. If the H lines are made to coincide, the corona line is shown 
distinctly to be by the side of and not above the Fraunhofer line belonging to 
calcium. 
For the greater part of these lines the agreement is as good as can be expected. 
