TOTAL SOLAE ECLIPSE OE JULY 18, 1860. 355 
The occultation of the largest solar spot, which I call c, h m sec. 
occurred at 2h. 10 m. 125 beats =2 10 50 
Deducting the difference between the pocket rrodsham| 
and Frodsham 3094 | 
It gives 2 2 39 
as the time by Frodsham 3094. This agrees within 0-5 second of the time noted by 
Mr. Becklet when a photograph of the phenomenon was taken in accordance with my 
signal, namely, 2 h. 2 m. 3 9 ’5 secs. Attention is called to the very exact accordance of 
the times recorded by myself and by Mr. Becklet, because I shall hereafter have to draw 
attention to certain conclusions which I have deduced, the soundness of which is depen- 
dent in part upon the epochs of the photographs having been accurately registered by 
Mr. Becklet. * 
After the occultation of the spot c, nothing worthy of record occurred until about 
2 h. 12 m., when a cluster of clouds formed very rapidly and unexpectedly in the imme- 
diate neighbourhood of the sun, and completely put a stop to both optical and photo- 
graphic observations. The clouds melted away about six minutes after they had formed, 
and thenceforward until the end of the eclipse all went on without interruption. 
I had never before witnessed so great an obscuration of the sun as that presented by 
this eclipse many minutes even before the totality occurred, and I was particularly 
struck by the change of colour in the sky, which had been gradually losing its azure 
blue and assuming an indigo tint, while at the same time I remarked that the sur- 
rounding landscape was becoming tinged with a bronze hue, which to my mind sug- 
gested the idea that the light of the sun near the periphery is not only less intense than, 
but possibly different in quality from, that of the centre*. Spectrum experiments at 
future great eclipses, when the sun’s crescent is reduced to an extremely narrow line, 
would set this question at rest, and might also have an important bearing on the line of 
investigations so ably inaugurated by Kikchhoef and Bunsen, into the composition of 
the sun’s atmosphere. Another phenomenon could not fail to attract attention. When 
the sun’s visible disk was reduced to a very narrow crescent, the shadows of all near 
objects became extremely black and sharply defined, whilst the lights, by contrast, 
assumed a peculiarly vivid intensity, the aspect of nature strongly recalling to mind the 
effects produced by the illumination of the electric light. Several minutes before the 
totality, the whole contour of the brown-looking lunar disk could be distinctly seen in 
the heavens. 
Only a few brief seconds, unfortunately, could be spared from the telescope after the 
totality had actually commenced ; but when I had once turned my eyes on the moon 
encircled by the glorious corona, then on the novel and grand spectacle presented by 
the surrounding landscape, and had taken a hurried look at the wonderful appearance 
* In connexion with this remark, compare Sir John Heeschel on the Chemical Eays of the Spectrum. 
Philosophical Transactions, 1840, Art. 82. 
