J. C. F. Zillner on a new Spectroscope. 65 
protuberance and the superposed spectrum may be permitted to 
stand out as strongly as-possible to the perception. 
Led by these conclusions, I have sought, with the aid of ter- 
restrial sources of light, to realize the conditions under which 
the protuberances are visible, in order, in this way, to test both 
methods and to convince myself of their practicability, For 
atmospheric light, depends essentially upon the cireumstance, 
that this light is composed of rays of all d 
€ superposition of an unhomogeneous mass of = upon 
a ti shining with homogeneous light and limited 
ing way. The wick of an alcohol flame was impregnated with 
chlorid of sodium and chlorid of lithium. At a distance of 18 
feet before this flame, a piece of plate glass was so set, at an 
angle of 45° to the direction of the observation, that the reflected 
Image of a petroleum flame at one side covered the faintly shin- 
ing alcohol flame, and, by reason of its much greater preseer 
rendered it completely invisible. About one foot before th 
Teflecting plate of glass, was situated a small lens of six inches’ 
focus, which directed a small image of the alcohol flame to the 
slit of the spectroscope. The latter was fastened to the end of 
& spring ten inches long, by means of which it could be put in 
tion of sufficient magnitude for about five minutes by 
* Photometrische Untersuchungen, ete., p. 105, fol., Leipsic, 1865. 
Am. Jour. Scr:—Szconp Series, Vou. XLIX, No. 145.—Jan., 1870. 
5 
