AMERICAN JOURNAL OF SCIENCE. 
[THIRD SERIES.] 
Art. XX.—On the Phosphorograph of a Solar Spectrum, and 
on the Lines of tts Infra-red Region;* by JOHN WILLIAM 
Draper, M.D., Professor of Chemistry in the University of 
New York. 
I Propose in this communication to consider: 1. The pecu- 
liarities of a phosphorograph of the solar spectrum as compared 
with a photograph of the same object; 2. The antagonization 
of effect of rays of higher by those of lower refrangibility. 
There is a striking resemblance between a photograph of 
that spectrum taken on iodide of silver and a phosphorograph 
taken on luminous paint, and other phosphorescent prepara- 
tions. There are also differences. 
I. Description oF THE PHOTOGRAPHIC SPECTRUM. 
In 1842, I obtained some very fine impressions of the first 
kind (on iodide of silver), and described them in the “ Philo. 
sophical Magazine” (November, 1842), and again in February, 
ne of these was made the subject of an elaborate 
three regions, 1. A middle one extending from the boundary 
of the blue and green to a little beyond the violet; in this 
Tegion the argentic iodide is blackened. 2. Below this, and 
*From the Proceedings of the American Academy of Arts and Sciences, 
Am. Jour. —— apr Vou, XXI, No, 123.—Marou, 1881, 
