262 H. Draper— Oxygen in the Sun. 
constitute the physical basis of the universe. We have seen 
that in some of its properties Radiant Matter is as material as 
this table, whilst in other properties it almost assumes the 
character of Radiant Energy. We have actually touched the 
border land where Matter and Force seem to merge into one 
another, the shadowy realm between Known and Unknown 
which for me bas always had peculiar temptations. I venture 
to think that the greatest scientific problems of the future will 
find their solution in this Border Land, and even beyond ; here, 
it seems to me, lie Ultimate Realities, subtle, far-reaching, won- 
erful. 
“ Yet all these were, when no Man did them know, 
Yet have from wisest Ages hidden beene ; 
That nothing is, but that which he hath seene ?” 
Arr. XXXVL—On the Coincidence of the Bright Lines of the 
gen Spectrum with Bright Lines in the Solar Spectrum ; by 
Henry Draper, M.D.* 
I INTEND in this paper to speak of the steps that led to the 
_ In 1857, after the meeting of the British Association at Dub- 
lin, some of the members, by the kindness of the Earl of Rosse, 
Society, June 13th, 1879, and reprinted 
“nia Journal is indebted for the 
ical Society. 
