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PROF. F. W. DYSON : DETERMINATIONS OF WAVE-LENGTH, ETC. 
DESCRIPTION OF PLATE 9. 
Spectrum of the Corona and higher Chromosphere, obtained at Sfax at 
the Total Eclipse of 1905, August 30. 
The photograph was exposed from about 15 seconds after the beginning of totality to about 15 seconds 
from the end, the slit being nearly tangential to the sun at the point of second contact and passing 
through a large prominence. The plate is made from a copy on glass (enlarged about four times) of 
the original negative. The two corona lines at 5117 and 5563 have been slightly accentuated to 
make them clearly visible on the plate. 
In the above diagram, which is drawn to scale, the line ABCDF gives the breadth of the spectrum 
obtained. The continuous spectrum is shown corresponding to AB and CF, but is strongest in the 
part AP>, which shows two faint lines at 5563 and 5117. The chromospheric lines are shown in the 
part corresponding to CD and end sharply. No chromospheric lines are seen in the part AB. 
j/ L u ** ^ 
