Fuly 15, 1886] 
NALORE 3258 
1st 
‘hundred 
| 
| 
hundred 
ard 
4th 
5th 
6th 
TABLE D.—Unknown Widened Lines observed at Kensington 
7th 
hundred hundred hundred|hundred/hundred 
| 
~~. 
13 
i | 
mt 
Se 
30. | 
33 
eZee 
aN: 
nN 
© PS Ooet = 
Ne 
~w Gm: 
PnP NOBUS GS 
hb: 
ni: 
7 Oa + 
+ Go ¢ 
N= 
i 
None 
NNe 
N Wwe p : 
NN AOO —Wu: 
=~: 
ow: 
Noo: 
17 
27 
19 
It 
20 
27 
nN: 
mu Nn: 
20 
Ist | 2nd | 3rd 4th sth 6th 7th 
hundred hundred | hundred) hundredjhundred) hundred |hundred 
5143 °2 #3 2 : 
5144°2 I 3 A | 
5144°5 4 He Wf one 
5145'5 296 Fowles. ; oer 
5145 haeegse ae 46 12 | 
51465 | 5 : eee Es soo if, 
Gi Sn ee |e Ae ee I 
5148'S ze = || ee Pe (ect |e 
SI4Qe 3) 2 32 31 36 4 35 
Sage) |: oe | if \_ 3 
RRit1@) Sp a ect | 3 
5149°3 | 8 2 | 8 8 x 
ate, $56 poo ff, Sac I | 
S51 Si ie ae 5 it 
5153'S lee nae 20 si ve 
5154 | [ 
ich Ya ee Se. til See > IP we 
5156 I 12) | 3i7 Tt | 82 91 95 
noe | | | |e a] - 
5159 gee | | § 13 It 4t 
5159°5 | | au hago | So | 86 | 57 
5160 Be I 4 | Oe 
5160°4 | 5 es 4 
5162 9 7 ny a Co 
5162°2 I 23 49 2 30} | eres 
5175 I!" “cee eco 208 se |e 3 
vations the lines recorded as most widened near the maximum 
haye not been recorded amongst metallic lines by either 
Angstrom or Thalén, and that many of them are not among 
the mapped Fraunhofer lines, though some of them may exist 
as faint lines in the solar spectrum when the observing con- 
ditions are best. 
The reduction of the latitudes of the spots is not yet 
completed. 
The result of these observations may be thus briefly stated. 
As we pass from minimum to maximum, the lines of the 
chemical elements gradually disappear from among those most 
widened, their places being taken by lines of which at present 
we have no terrestrial representatives. Or, to put the result 
another way—at the minimum period of sunspots when we know 
the solar atmosphere is quietest and coolest, vapours containing 
the lines of some of our terrestrial elements are present in sun- 
spots. The vapours, however, which produce the phenomena 
of sunspots at the sunspot maximum are entirely unfamiliar 
to us. 
The disappearance of the lines of iron, nickel, and titanium, 
and the appearance of unknown lines as the maximum is reached, 
is shown by curves in Fig. 1. 
The results, in my opinion, amply justify the working hypo- 
thesis as to the construction of the solar atmosphere which I 
published some years ago (Proc. Roy. Soc., 1882, p. 291). In 
the region of the spectrum comprised between 4860 and 5160, I 
find in the case of ir n, to take an instance, that sixty lines were 
distributed unequally among the spots in 1879 and 1880, many 
iron lines being visible in every spot. In the last observations, 
about the maximum, only three iron lines in all are seen among 
the most widened lines. These three lines also have been visible 
in four spots only out of the last hundred. The same thing 
happens with titanium and nickel, and with all the substances 
for which the reductions are finished. 
Iam quite content, therefore, to believe that iron, titanium, 
nickel, and the other substances very nearly as complex as we 
know them here, descend to the surface of the photosphere, in 
the downrush that forms a spot at the period of minimum, but 
that at the maximum, on the contrary, only their finest con- 
stituent atoms canreach it. It may also be remarked that these 
particles which survive the dissociating energies of the lower 
strata are not the same particles among the constituents of the 
chemical elements named which give the chromospheric lines 
recorded by Tacchini, Ricco, and myself. 
Having thus found the working hypothesis to which I have 
referred stand the severe test which the sunspot observations 
apply to it, I have gone further, and have endeavoured to extenc| 
it in two directions. 
