458 
Proceedings of the Royal Society 
Hydrogen — by induction-coil. 
(Here refer again to Talbot’s paper, presently to be read.) 
Spectroscopes. — Swan’s paper, in Edinburgh Transactions — Intro- 
duction of Collimator — estimation of the exces- 
sively minute amount of sodium required to give 
the D line. 
Universal Prevalence of Sodium, Lithium, &c. 
Discovery of New Metals. — Bunsen — Rubidium, Caesium. 
Crookes and Lamy — Thallium. 
Reich and Richter — Indium. 
Discoveries in Astronomy and Meteorology. 
Lightning. 
Aurora. 
Solar prominences and corona. 
Nebulae. 
Comets. 
Zodiacal light. 
Temporary stars. 
Huggins, Janssen, Lockyer, Secchi, &c. 
III. Absorption by glowing gases, from otherwise continuous spectra. 
Fraunhofer’s lines (Wollaston). 
Reversal of sodium line (exhibit). 
Hence atmospheres of sun, stars, &c. 
Brewster (in Edinburgh Transactions). 
Nitric peroxide — effects of heat and pressure. 
Atmospheric lines. 
Foucault. — Spectrum of incandescent carbon points, seen (by reflec- 
tion) through the voltaic arc (which itself gives them bright) 
shows the D lines reversed. 
Stokes — about 1850, gave, in consequence of W. H. Miller’s very 
accurate verification that the double bright line of sodium 
exactly corresponds in refrangibility with the double dark line 
D, the correct mechanical explanation of the phenomenon, 
with the mechanical illustrations still very often employed. 
Given, with general theory of solar and stellar chemistry, ever 
since (annually) by Thomson in his lectures. Give it. 
Angstrom — 1853. — “ Un gaz a l’etat d’incandescence emet des 
rayons lumineux de la meme refrangibilite que ceux qu’il peut 
absorber.” 
B. Stewart (Edinburgh Transactions, 1858-9). 
Extension of the Theory of Exchanges — The radiating power 
of a body is equal to its absorbing power, and that for every 
ray. Based on experimental facts. 
Heated pottery ware, with marked pattern, looked at in the 
dark. 
