NATURE 
[Fuly 22, 1886 
THE SUN AND STARS‘ 
IX, 
L>tT us consider the case, then, on the supposition of small 
masses of matter. Where are we to find them? The 
answer is easy ;—in those small meteoric masses which an ever- 
increasing mass of evidence tends to show occupy all the realms 
of space. 
In connection with this, perhaps I may be permitted to quote 
the following from one of my ‘‘ Manchester Lectures ” :— 
‘There is one point to which I think I may be permitted to 
draw your attention, although at present it rests merely upon an 
unindorsed observation of my own. I thought it would be 
worth while to try what would happen if I inclosed specimens of 
meteorites, taken at random, in a tube from which I subse- 
quently exhausted the air by a pump. After the pumping had 
gone on for some considerable time, of course we got an 
approach to a vacuum ; and arrangements were made by means 
of which an electric spark could pass along this apparent 
vacuum, and give us the spectra of the gases evolved from the 
meteorites. Taking those precautions which are generally sup- 
posed to give us a spark of low temperature, and passing the 
current, we got a luminous effect which, on being analysed by 
the spectroscope, gave us that same spectrum of hydrocarbon 
which Mr, Huggins, Donati, and others have made us perfectly 
familiar with as the spectrum of the head of a comet. ‘There, 
then, we get the atmosphere of meteorites, not necessarily car- 
bonaceous meteorites, but meteorites taken at random ; and this 
atmosphere is exactly what we get in the head of a comet. 
‘* Now let me go one step further ; and to take that step with 
advantage, allow me to refer to another point, . . . that whereas 
Schiaparelli has connected meteorites and falling stars with 
comets, Profs. Tait and Thomson, on the other hand, have con- 
nected comets with nebulz, both of them being, according to 
tho:e physicists, clouds of stones. Now how has one to carry 
these spectroscopic observations into the region of the nébule ? 
A Leyden jar was included in the circuit, and we had what is 
generally supposed to be an electric current giving us a very 
much higher temperature than we had before. What, then, was 
the spectrum? The spectrum, so far as the known lines were 
concerned, was the spectrum which we get from the nebulz ; 
for the hydrocarbon * spectrum, which we get from the atmo- 
spheric meteorites at a low temperature, was replaced by the 
spectrum of hydrogen; the spectrum of hydrogen coming, of 
course, from the decomposition of the hydrocarbon, with the 
curious, but at present unexplained, fact that we got the spec- 
trum indications of hydrogen without indications of carbon. In 
my laboratory work I have come across other curious cases in 
which compound vapours, when dissociated, only gave us one 
spectrum at a time—by which I mean that in a vapour consist- 
ing of two well-known substances, under one condition we only 
get the spectrum of one substance, and under another condition 
we get the spectrum of the other substance alone ; so in others, 
again, of both combined. The evidence seems, therefore— 
though I do not profess to speak with certainty—entirely in 
favour of the ideas of Sir William Thomson and Prof, Tait on 
the one hand, and of Schiaparelli on the other,” 
I have given the above extract to show that a mass of meteor- 
ites at a temperature higher than that found to exist in a comet's 
head could give us the hydrogen spectrum which was discovered 
with such richness in the Mova, which is represented in the 
spectra of most nebula, and which remained in the spectra of the 
Nova after all the other lines had gone. { 
These considerations enhance the interest of the ova to the 
spectroscopist if we accept the bright line observed in the star by 
Dr. Copeland and others to be veritably the chief nebula line. 
This line brightened relatively with each decrease in the 
brilliancy of the hydrogen lines. On December 8, 1876, it was 
much fainter than F, while by March 2, 1877, F was a mere 
ghost by the side of it. On any probable supposition the tem- 
perature must have been higher at the former date. 
Now it is well known that within certain limits the lines in 
the spectrum of a compound body get brighter with decrease of 
temperature, because at the higher one the compound almost 
entirely ceases to exist as such, and we get the lines of its con- 
stituents. It is a fair theory then to suggest that the famous 
* A Course of Lectures to Working Men delivered by J. Norman Lockyer, 
F.R.S., at the Museum of Practical Geology. Revised from shorthand 
notes. Continued from p. 230. 
* The Lectures from which I am quoting were delivered many years ago, 
before the spectrum was recognised to belong to carbon. 
nebula line may belong to acompound. Nay the fact as it stands 
alone further points to the possibility that the compound in 
question contains hydrogen as one of its constituents. 
At present we know very little indeed about these new stars. 
The star which appeared last year in the nebula in Andromeda 
is, 1f possible, still more difficult to understand, because, although 
it was so near the centre of the nebula in apparent position, we 
do not know that it was near the nebula locally, or whether it 
was simply in the line of sight. Therefore the views with regard 
to that star are much complicated by the fact that it is uncertain 
whether it was associated with a nebula. It may have had nothing 
to do with it. I have received this morning from Paris a photo- 
graph taken by the Brothers Henry, who are working now at the 
Paris Observatory, recording the very interesting discovery that 
apparently growing out of the side of one of the stars of the 
Pleiades is a real nebula. Those of you who remember the 
photographs of the corona during different eclipses will imagine 
that there may be some connection between this star and the 
surrounding nebula. Now it seems certain that there is some 
connection between this star and the nebula, and it may be that, 
in fact, what we call nebula in this case is a very considerable 
expansion of the star’s coronal atmosphere. So obvious is that 
suggestion, that I spent last night in trying to observe its spec- 
trum. The fog was too much for me, but still, although there was 
very little light, it did look very much as if there were some bright 
lines in the bright part of the spectrum of the star. And if that 
is so, it will not only show you the possible connection of the 
nebula in Andromeda with the new star in Andromeda, but it 
also shows you the importance of the question of area which I 
brought before you in the previous part of the lecture, if the 
bright lines we got are due, not to the star itself, but to the 
incandescent area which surrounds it. 
Finally, then, with regard to the new stars generally. That 
they are stars in our sense is, I think, quite impossible. Some 
of them, you know, lose their brilliancy in a very few weeks. 
Now we know that any body like the star which we are most 
familiar with—our sun—if ever it got to a sufficient degree of 
temperature to increase its light ten or twenty times, would not 
lose its temperature in ten or twenty days, or ten or twenty years, 
or ten or twenty thousand years, so that the more rapidly any of 
these bodies cool down, the less likely is it that the bodies which 
cool down haye any considerable mass. 
So obvious was that that on the appearance of the star in 1866 
I made the suggestion, as I have said, that the body which 
gave us this light might be quite close to us. Well that was 
negatived. It was found that it was not—that it was at a stellar 
distance—that it was no more possible to tell its distance than 
it was that of an ordinary star. 
We are driven then to the conclusion that, as we must account 
for a tremendous increase of light, and we know that this light 
was produced at a very great distance, and that one very large 
mass cannot be in question, we must distribute the light among 
a great many masses—the idea of a collision between two stars 
must give way to the idea of some action of a meteor-swarm in 
the case of a star already existing, like T Coronz, and of a 
collision between two meteor-swarms in the case of a new one 
like that of 1876; that seems a possible explanation of a great 
many of these ‘‘stars””—the components of meteor-streams driven 
to incandescence supplying that light in consequence of the in- 
numerable multitude of their components, the light dying out 
very quickly because these innumerable components are small 
and far apart. 
The next order of variable stars to which I shall refer you is 
very well represented by 8 Lyre. The curious point about this 
star is that it has a double minimum. Another star, » Argus, 
with a bright line spectrum, is also remarkable from the fact 
that its maximum varies in the same sort of way. 
In this star we get a number of differences. If you start from 
the maximum of the star you find it of three-and-a-quarter mag- 
nitude. It then in three-and-a-half days goes down to four-and- 
a-quarter. It then goes up so that in about six days it gets 
back again to its original brilliancy. It then goes down again, 
but does not stop where it did before, but goes half a magnitude 
lower, and then at last it ends the sequence of phenomena by 
getting up to its original brightness in thirteen days. 
Now, although we cannot explain how it is, we have the fact that 
a curve of that kind is associated with a bright line spectrum. In 
n Argiis, one of the most remarkable stars in the heavens, we have 
very much the same conditions. This star is in the southern hemi- 
