290 R. Meldola— Bright Lines in the Solar Spectrum. 
original appropriation of the Green ‘Trustees, it was not found 
necessary to draw upon this fund, though we are none the less 
chemicals and the manipulations is evident from the splendid 
success of Mr. Calley’s pictures of the corona. In twenty-five 
seconds he obtained a far more extensive and better photograph 
than the same instrument gave in 1870 at Jerez with an exposure 
lasting through the whole totality, more than two minutes. 
I ought not to close without a word of recognition of the 
courtesy and helpful kindness of our Denver friends. I do not 
know what they could have done that they did not, to aid us 
in our work and make our stay among them pleasant. 
Princeton, September 6, 1878. 
ArT. XXXIU.—On a Cause for the Appearance of Bright Lines 
in the Solar Spectrum; by RapHarL Me.po.a, F.R.A.S., 
F.C.8., &e.* 
paper is the well-known “line spectrum” seen when power” 
* From Phil. Mag. for July, 1878. + Nature, xvi, 364, August 30, 1877. 
The oxygen spectrum referred to in the above-mentioned 
u 
