SS 
automatic spectroscope having the dispersive power of 
13 prisms. The instrument was loaned for the occasion 
by the trustees of the College, who, for the good of 
science, have never hesitated to send their most valuable 
apparatus to any portion of the earth; and thus far, I 
am happy to say, have met with no. loss in so doing. 
Our observatories, one for the transit instrument, one 
for the meteorological apparatus, and one for the equato- 
rial, were “shanties” of rough boards, placed upon the 
summit of a slight elevation, some 150 yards S.E. of the 
railway station, and some 40 or 5oft. above the track. 
The altitude of the observatory was about (3:30 ft. above 
the sea; the approximate eae was 44° 7’; the longi- 
tude about rh, 53°20 14m, 
west of Greenwic! s, the 
accurate reducti not yet, 
completed. ah 
To the east the chatizon was eet eh i hills of no 
great apparent elevation, nor was there anything in the 
general aspect of the nearer ‘landscape to remind the care- 
less observer of his altitude, To the north, at a distance 
of about three miles, but seeming not more than half a 
mile away, rose some picturesque piles of granite several 
hundreds of feet in height ; t to the north-west lay the so- 
called Laramie hills; and from the north-west to the 
south, across the. broad green Laramie plains, toward the 
mountains, many of them capped with perpetual snow. 
In the south were Long’s and Gray’s 
away ; nearly west lay somewhat nearer ‘the great mass 
of Medicine Bow; and between them, over the lower 
ridges, rose some of the high mountains of the Colorado 
parks. None of these snow-capped peaks have an eleva- 
tion of less than 13,000: ft., and several exceed 14,000. 
Our principal object was to ascertain what advantage 
would accrue to astronomical, and especially to spectro- 
scropic, work, by placing the instrument. at a great eleva-— 
tion. Theory declares that the gain ought to be great, 
since it is certain that our atmosphere, by its continual 
currents, its impurities, and its reflectivé power, is a most 
serious hindrance to telescopic work, and at the height of 
8,000 f;,—more than a fourth of the whole is left below. 
The experiment of Prof. Piazzi Smyth, in 1856, on the 
Peak of Teneriffe, had already given a practical demon- 
stration of the fact, so far as relates to ordinary telescopic 
work ; but that was before the day of spectroscopy. 
Although, on account of unfavourable weather, the 
amount of work accomplished was to some extent dimi- 
nished, the results obtained were of considerable interest 
and value. 
In the first place, the geographical co-ordinates of the 
station were completely determined ; so that henceforth 
it will be a reference point and base for all the numerous 
surveys, geological and others, which are going on in 
that part of the country. 
Then a complete hourly meteorological record was 
obtained for nearly the whole of the months of June, July, 
and August, a record which, from the exceptional charac- 
ter of the station, on the very back-bone of the continent, 
must possess the highest value, unless the fact that the 
season was also an exceptional one should prevent us from 
applying confidently to other years the conclusions it would 
indicate. 
If we may credit the residents of the country, especially 
an old trapper who had lived among the mountains for 
nearly twenty years, the amount of cloudy and rainy 
weather during the summer was most unusual. Deduct- 
ing a single week, during which every night and the 
greater part of every day was fine, clear nights were very 
rare, and clear days only a little less so. “Indeed during 
our whole stay there were but two afternoons during which 
work upon the sun could be kept up uninterruptedly from 
noon to sunset, though during the same time there were 
more than twenty mornings. 
Undoubtedly the explanation of this state of things is 
NATURE 
| to stellar observation, I 
aks, some 60 miles 
[ Dec. 12, 187: 
to be found in the enormous quantity of snow which fe 
last winter, and was:still, in the middle of July, lying 8 fi 
deep on the platean at the base of the Medicine Boy 
mount, 
Whenever the sky was unclouded the air was usually of - 
most exquisite transparency. At night multitudes of stars, 
invisible at lower elevations, were easily seen ; so that it — 
was estimated that nearly all the stars of the seventh 
magnitude were fairly within reach of the naked eye. For | 
instance, in the quadrilateral which forms the bowl of he 
“ Dipper” I could see distinctly nine stars, with glimpse 
of one or two more, while at home I can only percei e 
the three brightest of them. 
The power of the telescope. was correspondingly | in- 
creased. Without being able to rot é a great deal of time 
é hat, with my 9 #5 
rything could be fairly seen 
in ‘the reach of a 12-inch 
inches of aperture, nea’ 
which, at the sea-level, is w 
object-glass. 
‘Some most exquisite views of Satiien will always be 
remembered, in which, notwithstanding the planet’s near- 
ness to the horizon, the i inne e ‘and the details 
and markings of the rin ally a dark stripe upon 
the outer ring, about a thea its th from the outer 
edge, were clearly sho wn under powers ra 
to 1,200, © 
But in the e of the spectroscope “the: advantage was: 
even greater. At Hanover I had been abl ble to make out a 
list of 103, brigh lines 3 in the spectrum. f the chroma 
sphere; at SI an the number was extended to 2733 
and at moments of unusual solar disturbance there were 
glimpses of at least as many more. 1 
Sulphur, strontium, and cerium are pretty conclusively 
shown to be constituents of the solar atmosphere. Zinc, 
erbium, did ium, and iridium are also! indicated, but 
not so certa =e 
At the very base of the chromosphere, and to a dis- 
tance of perhaps 1" or 15" from the edge of the photo- 
sphere, it was found that those dark lines which are not 
actually reversed lose their intensity, and vanish more or 
less completely: This is substantially a confirmation 
an old and somewhat disputed observation of Secchi’s, 
who reports at the edge of the sun a layer giving a con- 
tinuous spectrum. 
This is not strictly correct, however, since when the 
transparency of the air is so much increased as to cause 
the most persistent of the dark lines to vanish, a multi- 
tude of the others appear reversed. There can be little 
doubt that were the effect of our own atmosphere entirely 
removed, this lowest portion of the solar atmosphere would 
give the same spectrum of bright lines which is seen at 
the beginning and end of totality during an eclipse. 
It is noteworthy that of the 170 new lines found in the 
chromosphere spectrum, not a single one lies below C, 
and that for no want of careful examination. The only 
new lines of much importance are the two Hs at the ex , 
treme violet end of the spectrum. These were found 
almost constantly reversed, probably quite so, but the 
observation was so difficult that we could not be perfectly " 
sure of it on every occasion. 
What is still more remarkable, it was found that these 
two lines (not the hydrogen lines, as has been erroneously 
reported) are also usually, and Iam pretty confident always, 
reversed in the spectrum of sun-spots, not so clearly, more- 
over, in the nucleus as in the penumbra, and over a some 
what extensive region surrounding it. This reversal of 
the H lines does not involve at all the disappearance of 
the dark shade, but a bright streak rather than a line 
makes its appearance in the centre of the shade, whi ‘ 
itself is, if anything, a little intensified. he 
The spectra of several different spots were carefully 4 
studied, and a catalogue was drawn up of 155 lines wh 
are more or less affected, usually by being greatly widened, 
but in some cases by a ’ weakening or reversal, Several 
ee 
5a 
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