of observing contacts at the Sun’s limb. 377 
lines in it, was also visible, evidently due to the corona. Its 
light, tested by a tourmaline applied next the eye, proved to 
e very strongly polarized in a plane passing through the cen- 
ter of the sun, J am not sure, however, but that this polariza- 
tion, as suggested by Prof. Pickering, may have been produced 
by the successive refractions through the prisms. This expla- 
nation at once removes the difficulty otherwise arising from the 
K 1350 and K 1474, These coincidences are certainly very re- 
markable, especially the last. The positions of the faint lines 
(K 1250 and 1350) being only estimations, very little weight 
can of course be given them. But as to the position of 1474 
In the corona spectrum there cannot be the least doubt. It 
