710 Scientific Proceedings, Royal Dublin Society. 
DESCRIPTION OF PLATES. 
Tur three Plates reproduce the flame spectra of six Meteoric Irons and 
three Siderolites. Along the middle of each flame spectrum is a spark 
spectrum of two alloys, which yield lines of air, cadmium, lead, tin, 
bismuth, and silver, the wave-lengths of which are accurately known. 
The wave-lengths of the lines in the flame spectra are easily deter- 
mined from a curve of wave-lengths drawn from the lines in this spark 
spectrum. 
The principal lines of the elements present cannot be marked 
on every spectrum, but they are indicated by the symbols or names 
of the elements on different plates, thus :— 
On Plate XXII.: sodium, calcium, lead, nickel, rubidium, 
potassium, silver, gallium, and copper. On Plate XXIII.: cobalt 
and iron. On Plate XXIV.: manganese. 
Puats XXII.—Meteoric Irons :— 
Spectrum 1. Virginia (1). 
5 2. Virginia (2). 
os 3. Arva, Hungary. 
Puatz XXIII.—Meteoric Irons :— 
Spectrum 1. Tolucca, Mexico. 
a 2. Cation Diablo, Arizona. 
oy 3. Thunda, Queensland. 
Pratt XXIV.—Siderolites :— 
Spectrum 1. Atacama, Chili. 
3 2. Estherville, Iowa. 
a4 3. Imilac, Chili. 
