132 
NATURE 
[Fune 16, 1870 
are the “radiance” and dull prominences shown in the American 
photographs. 
I now return to my observations of the spot. On the 16th, 
the last of the many umbre was close to the limb, and the 
most violent action was indicated occasionally. I was working 
with the C line, and certainly never saw such rapid changes of 
wave-length before. The motion was chiefly horizontal, or 
nearly so, and this was probably the reason why, in spite of the 
greataction, the prominences, three or four of which were shut 
out, never rose very high. 
I append some drawings, made, at my request, by an artist, 
Mr. Holiday, who happened to be with me, and who had never 
seen my instrument or the solar spectrum widely dispersed before. 
I attach great importance to them, as they are the untrained ob- 
servations of a keen judge of form. 
The appearances were at times extraordinary and new to me. 
The hydrogen shot out rapidly, scintillating as it went, and sud- 
denly here and there the bright line, broad and badly defined, 
would be pierced, as it were, by a line of intensely brilliant light 
parallel to the length of the spectrum, and at times the whole 
prominence spectrum was built up of bright lines so arranged, 
indicating that the prominence itself was built up of single dis- 
charges, shot out from the region near the limb with a velocity 
sometimes amounting to 100 miles a second. After this had 
gone on for a time, the prominence mounted, and the cyclonic 
motion became evident; for away from the sun, as shown in 
my sketch, the separate masses were travelling away from the 
eye; then gradually a background of less luminous hydrogen 
was formed, moving with various velocities, and on this back- 
ground the separate ‘‘bombs” appeared (I was working with 
a vertical spectrum) like exquisitely jewelled ear-rings. 
It soon became evident that the region of the chromosphere 
just behind that in which the prominence arose, was being 
driven back with a velocity something like twenty miles a second, 
the back-rush being so local that, with the small image I am 
unfortunately compelled to use, both the moving and rigid por- 
tions were included in the thickness of the slit. I saw the 
two absorption-lines overlap. 
These observations were of great importance to me; for the 
rapid acticn enabled me to put together several phenomena I 
was perfectly familiar with separately, and see their connected 
meaning. 
They may be summarised as follows, and it will be seen that 
they teach us much concerning the nature of prominences. When 
the air is perfectly tranquil in the neighbourhood of a large spot, 
or, indeed, generally in any part of the disc, we see absorption- 
lines running along the whole length of the spectrum, crossing 
the Frauenhofer lines, and they vary in depth of shade and 
breadth according as we have pore, corrugation, or spot under 
the corresponding part of the slit—a pore, in fact, is a spot. 
Here and there, where the spectrum is brightest (where a bright 
point of facula is under the slit) we suddenly see this appearance 
—an interesting bright lozenge of light. This I take to be due 
to bright hydrogen at a greater pressure than ordinary, and this 
then is the reason of the intensely bright points seen in ranges 
of faculze observed near the limb. 
The appearance of this lozenge in the spectroscope, which 
indicates a diminution of pressure round its central portion, is 
the signal for some, and often all, of the following phenomena :— 
1. A thinning and strange variation in the visibility and 
thickness of the hydrogen absorption-line under observation. 
2. The appearance of other lozenges in the same locality. 
3. The more or less decided formation of a bright promi- 
nence on the disk. 
4. If near the limb, this prominence may extend beyond 
it, and its motion-form will then become more easy of obser- 
vation. In such cases the motion is cyclonic in the majority 
of cases, and generally very rapid, and—another feature of a 
solar storm—the photospheric vapours are torn up with the in- 
tensely bright hydrogen, the number of bright lines visible deter- 
mining the depth from which the vapours are torn, and varying 
almost directly with the amount of motion indicated, 
Here, then, we have, I think, the chain that connects the 
prominences with the brighter points of the faculze. 
These lozenge-shaped appearances, which were observed close 
to the spot on the 16th, were accompanied by the ‘‘throbs” of 
the eruption, to which I have before referred ; while Mr. Holi- 
day was with me—a space of two hours—there were two out- 
bursts, separated by a space of almost rest, and each outburst 
consisting of a series of discharges, as I have shown. I subse- 
quently witnessed a third outburst. 
on all three were the same in kind. 
On this day I was so anxious to watch the various motion- 
forms of the hydrogen-lines, that I did not use the tangential slit. 
This I did the next day (the 17th of April) in the same region, 
when similar eruptions were visible, though the spot was no 
longer visible. 
Judge of my surprise and delight, when upon sweeping along 
the spectrum, I found HuNDReEDs of the Frauenhofer lines beauti- 
fully bright at the base of the prominence !!! 
The complication of the chromosphere spectrum was greatest 
in the regions more refrangible than C, from E to long past 4, 
and near F, and high pressure iron vapour was one of the chief 
causes of the phenomenon. 
I have before stated to the Royal Society that I have seen 
the chromosphere full of lines; but the fulness then was as 
emptiness compared with the observation to which I now refer, 
A more convincing proof of the theory of the solar constitu- 
tion, put forward by Dr. Frankland and myself, could scarcely 
have been furnished. ‘This observation not only endorses all my 
former work in this direction, but it tends to show the shallow- 
ness of the region on which many of the more important solar 
phenomena take place, as well as its exact locality. 
‘he appearance of the F line, with a tangential slit at the 
base of the prominence, included two of the lozenge-shaped 
brilliant spots to which I have before referred ; they were more 
elongated than usual—an effect of pressure, I hold, greater 
pressure and therefore greater complication of the chromosphere 
spectrum ; this complication, is almost impossible of observation 
on the disc. 
It is noteworthy that in another prominence, on the same side 
of the sun, although the action was great, the erupted materials 
were simple, 7.¢., only sodium and magnesium, and that a mode- 
rate alteration of wave-length in these vapours was obvious. 
Besides these observations on the 17th, I also availed myself of 
the pureness of the air to examine telescopically the two spots 
on the disc, which the spectroscope reported tranquil as to up 
and down rushes. I saw every cloud-dome in their neighbour- 
hood perfectly, and I saw these domes drawn out, by horizontal 
currents, doubtless, inthe penumbre, while on the floors of the 
spots, here and there, were similar cloud-masses, the distribution 
of which varied from time to time, the spectrum of these masses 
resembling that of their fellows on the general surface of the sun. 
I have before stated that the region of a spot comprised by 
the penumbra appears to be shallower in the spots I have 
observed lately (we are now nearing the maximum period of sun 
spots) ; I have further to remark that I have evidence that the 
chromosphere is also shallower than it was in 1868, 
I am now making special observations on these two points, as 
Leansicer that many important conclusions may be drawn from 
them. 
Zoological Society, May 26.—G. R. Waterhouse, V.P., 
in the chair. <A letter was read from Mr. W. H. Hudson, 
C.M.Z.S., containing remarks on birds observed in and around 
Buenos Ayres, being the fourth communication received from 
this gentleman on the same subject.—Mr. R. B. Sharpe exhibited 
and made remarks on a specimen of a rare Asiatic bird, Podoces 
panderi, from the collection of Lord Lilford.—Professor Owen 
read the sixteenth of a series of memoirs on Dinornis, con- 
taining an account of the trachea and of some other internal 
organs of certain species of this genus, together with a descrip- 
tion of the brain and some nerves and muscles of the head of 
Apteryx australis.—Dr. J. Murie read a paper on the anatomy 
of the Prongbuck (Atilocapra americana), founded on the exami- 
nation of the specimen of this animal which had died in the 
Society’s Gardens in the year 1867.—A communication was read 
from Dr, A. B. Meyer, containing remarks on the poisonous 
glands of the snakes of the genus Caé/ophis, being supple- 
mentary to his paper on the same subject published in the 
Monatsberichte of the Academy of Berlin.—A_ conmunication 
was read from Surgeon Francis Day, F.Z.S., containing notes 
on some fishes from the western coast of India, amongst which 
were several species described as new to science. —Mr. H. Adams 
communicated the descriptions of some new species of Jand and 
fresh-water shells obtained by Mr. E, Bartlett in Eastern 
Peru, and by Mr. R. Swinhoe in China and Formosa. Mr, 
Adams also described two new species of land shells from Africa. 
June 3.—Mr. 
Several papers were read and illus- 
The phenomena observed 
Aeronautical Society, 
F.R.S., in the chair. 
James Glaisher, © 
————o 
