a Fs r ; = So ad res 4 Car 
576 NATURE ~* [ April 20, 1882 
which I allude. If these early forms really exist at the | and reappearance of the sun, but perhaps even for two or 
present moment in the hottest portions of the Sun, the 
spectrum of which is marvellously like that of Sirius, we 
ought not to expect these early forms to be confined to 
one of our earthly constituents. But what are the facts? 
The facts are very precise indeed. On this map we 
have the result of all the individual observations of the 
spots and the flames to which I refer. What we find is, 
that to every prominent line in the spots and in the 
storms, although these two have no line in common, 
there is a line common with our present instrumental 
appliances to iron, vanadium, and chromium, another 
common to iron and titanium and so forth ; and 
the lines shown by Angstrém and Thalén, as common to 
two or more elements, are precisely those lines which are 
thickened in spots or are brightened in storms, so that the 
view we have here of early forms of matter is absolutely 
justified by this massing of lines here and there. We 
have been able to increase the number of ‘basic’ lines 
over this region by observing the lines constantly thick- 
ened in the spots. This does away at once with the idea 
that all these basic lines arise from the fact of the lines 
being double. For if they are to be doubled there is no 
reason why the 60 per cent. of lines neglected by the spots 
and the storms should not have been double lines. But 
neither Angstrém, nor Thalén, nor myself have picked up 
one of these basic lines when we passed from the atmo- 
sphere of the spots or the special atmosphere of the flames. 
Now, there is a moral to this, if you will allow me to en- 
force it. There is an eclipse of the Sun next year, lasting 
only, I am sorry to say, a minute and a very few seconds ; 
but there is to be another the year after, lasting nearly six 
minutes, but it happens to be in a part of the world where 
it is always afternoon. In the observations of the future we 
must pay attention to these lines which have been picked 
out by nature herself in these spots and prominences. If 
I observed either of these eclipses, I should be content to 
fix my instrument on three iron lines between 4900 and 5000 
ten millionths of a millimetre, because, of these three lines 
which are in the Fraunhofer spectrum, two have always 
been seen in spots without the third, and the third has 
always been seen in the prominences without the other 
two. If, then, the spectrum of the flames represents 
the lowest part of the atmosphere, and the spectrum 
of the spots represents the atmosphere above the flames 
and below the corona, than we ought to see these lines 
different in the corona, and in the corona we ought to see 
the lines which are dropped in these two regions. Of the 
twelve lines between 4,900 and 4,957, only one is picked 
out by Thalén for intensification, and that particular line 
is the line seen alone in the region of the prominences. 
There are eleven lines which are absolutely untouched by 
Thalén, showing, that absorption must be proceeding 
somewhere ; and itis most interesting to determine where 
it is goingon. In the Indian eclipse, in 1871, I saw these 
lines reversed before totality. I saw as it were hundreds 
of lines; but if I had confined my attention to the three 
lines I should have got a better idea of what the magnifi- 
cent flashing out of those lines meant. It has been called 
the reversing layer; but I do not now believe it is the 
reversing layer for a moment ; for, when it comes to be 
examined, we shall probably find that scarcely any of the 
Fraunhofer lines owe their origin to it, and we shall have a 
spectrum which is not a counterpart of the Solar spectrum.” 
As further thought led me to believe that this method of 
observation was one of the most important that could be 
employed next May, I laid great stress upon it in a 
memorandum which I subsequently submitted to the 
Government Committee on Solar Physics, and I pointed 
out to them at the same time that from what Captain 
Maclear and myself observed in India in 1871, there was 
a great probability, that on this question facts might be 
collected, not only at the exact moments of disappearance 
three minutes both before and after totality, by keeping 
the slit of the spectroscope very carefully on a point 
where the cusps were narrowest. 
The memorandum to which I have referred runs as 
follows :— 
“The total eclipse of the sun which takes place in May 
next year will be visible in such an accessible region, that 
it is to be hoped that the precedents of 1860, 1870, 1871, 
and 1875 will be followed, and steps taken to secure 
observations, the more especially as the eclipse will hap- 
pen somewhat near to the period of maximum sun-spots, 
and will allow of a comparison being made with the 
results obtained in India in 1871. 
“ There is one new point (it isnot necessary now to refer 
to the importance of registering the ordinary phenomena) 
to which I beg to invite the attention of the Committee. 
“The discussion of the sun-spot spectra recently ob- 
served at Kensington, and of the prominence spectra 
observed at Palermo by Tacchini, since 1872, throws 
some doubt upon the validity of some of the conclusions 
based upon the results obtained by the English and 
American Government Eclipse Expeditions in 1870. 
“Tn that year, at the moment of the disappearance of 
the sun, a large number of bright lines was seen to flash 
out, and it was supposed that these lines composed the 
spectrum of a thin layer near the sun, and were those 
the reversal of which produced the lines of Fraunhofer. 
“Hence this layer has been termed, and generally 
accepted to be, the reversing layer. The conclusion 
seemed to be in harmony with the results obtained by 
Dr. Frankland and myself, who gave reasons for showing 
that the region in which the absorption of the elementary 
bodies of greater atomic weight than hydrogen, magne- 
sium, and sodium must be below the chromosphere. This 
view was put forward at a time when the elementary 
nature of the so-called elements was never questioned, 
and before any of the recent results had been obtained. 
‘The observations made by the Government Eclipse 
Expedition which went to India in 1871, showed that this 
flashing out of lines was a real phenomenon; but as the 
observation was a general one, and as during the eclipse 
the Fraunhoferic lines were invisible, there was no abso- 
lute demonstration of the identity of the two spectra. 
“The facts, now beyond question, that gud the same 
element, the spectra of spots and flames differ, and that 
the spectra differ widely among themselves, throw great 
doubt upon the conclusion to which reference has been 
made. 
“ First they seem to indicate that some of the absorp- 
tion takes place at a higher level than that occupied by 
the so-called reversing layer. 
“Secondly they seem to indicate that many of the 
brightest lines seen during the flash to which reference 
has been made may be those seen thickened in spots or 
intensified in the prominences, although they do not 
occur except as excessively faint lines among the Fraun- 
hoferic lines. 
“In short, in 1870, the fact that the spot and 
prominence spectra are so widely different from the 
ordinary solar spectrum, had not received the attention it 
must receive in the light of the most recent inquiries, and it 
was taken for granted that because a large number of 
lines was seen, that therefore they occupied the same 
positions as the large number of lines which compose the 
ordinary solar spectrum. | 
“The recent work seems to show that the complete. 
absorption spectrum of any one element is produced, not 
at one level, but at various levels, the absorption of all 
the levels being added together to give us the complete 
result. . 
“Tf this be so, the lines seen in the flash will not all be 
Fraunhoferic lines with the ordinary intensities. ] 
