422 H. Draper—Photographing the 
The experiments were interrupted, in the spring of 1874, by 
going to Washington to superintend the photographic prepara- 
tions for the United States observations on the Transit of 
enus. 
Since that time my experiments have been divided into two 
shes i an work on the spectra of the elements and particu- ’ 
arly the non-metals, and has led to the discovery of oxygen 
in the sun. : 
In 1876, Dr. Huggins published a note in the Proceedings 
of the Royal Society, accompanied by a wood-cut of the spec- 
trum of Vega, with a comparison solar spectrum. Seven lines 
were observed in the spectrum of Vega. In the summer and 
autumn of 1876 I made several photographs of the spectra of 
Vega, a Aquile and Venus, and sent a note concerning them 
to this Journal. 
Since that time Dr. Huggins has pursued the subject actively 
in spite of the London atmosphere, and has attained very fine 
results, which I had the pleasure of seeing at his observatory ’ 
light of stellar — rolonged exposures of the sensitive 
plate are required. 
bag od rciea made by Wratten & Wainwright of London ; 
