Fan. 19, 1871] 
of rapidly recording the position of the lines noted in the 
Spectroscope, devised by Professor Winlock, proved of 
too essential service to be left unnoticed. Each spectro- 
scope was provided before leaving America with this 
attachment, which enabled the observer to record the 
position of the lines as fast as he could point on them, 
and with a precision that compared favourably with 
micrometrical measurement. 
I pass to the work done by each observer. 
The Spectroscope used by Prof. Young was the one 
recently described in your pages ; and through this he was 
enabled to watch the occultation of the protuberances of 
the photosphere, and announce the approach of the moon, 
some fifteen seconds before “ first contact.” At this time 
the sky about the sun was nearly clear, and numerous 
successive photographs were taken, with the accompany- 
ing chronographic record of the instant of exposure. 
Heavy clouds then obscured the sun, at intervals, till 
totality was very near, when a happy fortune gave us a 
few minutes of almost clear sky while it lasted. 
It is important to explain that, though the sky was so 
little obscured that the Corona was visible during the 
whole of totality, there was during most of this time 
a very slight haze. I recall a short view of sky, dis- 
tinctly blue in spite of the darkness ; and the structure of 
the protuberances was continuously visible through the 
telescope ; nevertheless, the presence of this partial haze 
should be remembered, as having a possible bearing on 
some of the conclusions to be drawn from what follows. 
I give as nearly as I briefly can the principal results of 
each observer, as regards the corona only. 
Professor J. Winlock, using a spectroscope of two prisms 
on a five-and-a-half-inch achromatic (directed by Mr. A. 
Clark as the finder) found a faint continuous spectrum, 
without dark lines. 
Of the bright lines, the most conspicuous was 1474. 
Kirchhoff, which was followed all around the sun to at least 
20’ from the disc. It may be here remarked that all the 
spectroscopes showed this as much the most conspicuous 
coronal line. A number of other lines were also noted, and 
their position recorded by the apparatus just referred to. 
Professor Young’s observations of this line were similar ; 
he estimates its least extension at one half the solar 
diameter. With the slit of his spectroscope placed tangen- 
tially at the moment of obscuration, and for one or two 
seconds later, the field of the instrument was ///ed with 
bright lines. As far as could be judged, during this brief 
interval every non-atmospheric line of the visible spec- 
trum showed bright ; an interesting observation, con- 
firmed by Mr. Pye, a young gentleman whose voluntary 
aid proved of much service. The observation of Mr. Pye 
was made with a spectroscope of one prism, before which 
was placed a small telescope arranged at Prof. Young’s 
suggestion, not to give, as usual, a definite image on 
the slit, but to supply light from all portions of the corona 
and neighbouring sky with more intensity than would be 
furnished by directing the instrument toward the sun 
without it. From the concurrence of these quite indepen- 
dent observations, we seem to be justified in assuming the 
probable existence of an envelope surrounding the Photo- 
sphere, and beneath the Chromosphere usually so called, 
whose thickness must be limited to two or three seconds 
of arc, and which gives a discontinuous spectrum consist- 
ing of all, or nearly all, the ordinary lines, showing them, 
that is to say, drigh¢ on a dark field. 
Mr. Abbay, of Wadham College, Oxford, assisted with 
a Spectroscope prepared by Prof. Young for collateral 
observations to his own, and obtained results which have 
already been made public. 
The Polariscope was used by Prof. Pickering at a 
station half a mile distant from the rest of the party. 
Using successively an Arago Polariscope, one of the form 
employed by Prazmowski, and a Savart, he is understood 
to have obtained with all three, results pointing to a radial 

NATURE 
| which differ in some degree from each other. 

229 

polarisation of the Corona, The light covering the moon’s 
disc he observed to be polarised throughout in the same 
plane, and the observations showed that the Arago and 
other Polariscopes dependent on colour were sufficiently 
delicate to determine this plane with accuracy. 
_ At the same time Mr. Ross, his assistant, using the 
instrument employed by Prof. Pickering in the last 
eclipse, obtained the same results as were then found. 
Mr. Ross used a modification of the Bunsen photo- 
meter, and obtained several concordant measurements, 
showing that the light was equal to that of a standard candle 
at two feet. 
The writer used a Savart’s polariscope attached to a small 
telescope of 14 inches aperture, and havinga field of about 2°. 
The observations with the Savart’s polariscope being 
subject to ready misconception, the preparation for ob- 
servation and the appearance during it are here given 
with some minuteness. 
Before the eclipse the Savart was so adjusted that the 
bands were most distinct when vertical, viewing the meri- 
dian sun reflected from water. None were visible when 
the sun was directly scrutinised before or after totality. 
During totality the appearance which presented itself 
was unexpected. 
The bands were distinctly seen on the corona, and were 
brightest where normal to the limb and where tangential 
to it. As the polariscope was slowly rotated, no marked 
diminution of their brightness was seen, and when it had 
been turned through 45° they were as bright as before ; 
distinctly visible even in colour, and they so remained, 
the rotation being continued for greater security through 
a whole revolution, during the whole time they presented 
the appearance described, and characteristic of radial 
polarisation. They were not noticed on the disc of the 
moon, but this may well have been from the observer’s 
attention being so exclusively directed to verifying their 
persistency on the corona. 
The writer also employed a good achromatic, of four 
inches aperture, with a power of about 150, in the direct 
study of the coronal structure with negative results. 
On the closest scrutiny of the part nearest the sun, 
nothing was seen but a nearly uniform diffuse light, ex- 
cept that one “dark ray” in the field was noticed to be 
absolutely straight and nearly radial. The outline of the 
Corona was roughly quadrangular, and a heavy field bar 
provided for the purpose being carefully set during totality 
in the direction of the longer diagonal, was found on sub- 
sequent estimation to make an angle of as nearly as pos- 
sible 45° with the vertical. 
The “red flames” were beautiful objects, as incidentally 
noticed during the telescopic scrutiny of the Corona, but 
not, I may add, more distinctly or more in detail than I 
had viewed them the day before through the Spectroscope 
of Professor Young. 
The coronal structure is well shown on a photograph 
obtained by Mr. Willard during totality ; a very interesting 
drawing of it was also taken by Mr. Gordon, a gentleman 
resident in the vicinity; and all the observers have 
descriptions to give of its appearance to the naked eye, 
If I com- 
pare my impressions with those of others, or even with 
my own of last year, I find difference enough to suggest 
the probability of considerable “ personality” in all such 
statements. In some well-marked features all agree, in 
| other minor ones such difference exists that one might 
almost say each sawa different Corona, The observations 
with the Spectroscope and Polariscope are happily more 
removed from uncertainty. 
The conclusions reached with both are not perhaps as 
absolute as they would have been with the cloudless sky 
of last year’s Eclipse, they are still such as to fully justify, 
we may hope, the cost of labour and time in obtaining 
them, and which none of those present can regret. 
S, P, LANGLEY 
