ON THE TOTAL SOLAR ECLIPSE OF AUGUST 29, 1886. 
341 
Summary of Results. 
1 . The continuous spectrum of the corona has the maximum of actinic intensity 
displaced considerably towards the red, when compared with the spectrum of Sun 
light. This proves that it can only in small part be due to light scattered by small 
particles. 
2 . While on the two previous occasions on which photographs of the spectrum 
were obtained lines showed themselves outside the limits of the corona, this was not 
the case on this occasion. Hence there must have been less light, due to the 
scattering in our atmosphere. 
3 . Calcium and hydrogen do not form part of the normal spectrum of the corona. 
The hydrogen lines are visible only in the parts overlying strong prominences ; the 
H and K lines of calcium, though visible everywhere, are stronger on that side of the 
corona which has many prominences at its base. 
4. The strongest corona line on the present occasion was at X= 4232’8; this is 
probably the same line as 4233'0 often observed by Young in the chromosphere. 
5 . Of the other strong lines, the positions of the following seem pretty well estab¬ 
lished — 
40567 , 4084 - 2 , 4089-.3, 4169 - 7 , 41950 , 4211 - 8 , 
4280-6, 4365-4, 4372 2 , 4378-1, 4485-6, 4627-9. 
The lines printed in thicker type have been observed also at the Caroline Island and 
Egyptian Eclipses. 
6 . A comparison between the lines of the corona and the lines of terrestrial elements 
has led to negative results. 
Suggestions concerning the Spectroscogiic Arrangements in future Eclipses. 
1 . In order to distinguish better any difference in the spectra between different 
parts of the corona, a larger image should be thrown on the slit. A lens of 4 or even 
5 feet focal length might be employed with advantage. The aperture of the lens need 
not be larger than that required to fill the collimator with light, 
2 . The width of slit should be equal to yX/R, where II is the useful aperture of 
the collimator lens, X the wave-length, and f the focal length of the collimator. In 
order to prevent difficulties, due to dark lines, &c.,y should be about 4 or 5 feet. 
3. A resolving power of about 12 in the yellow, if full use is made of it, seems 
sufficient. This can be obtained either by one large prism or two small ones. 
