APPENDIX. 207 
are, and to diminish the time of a given number of vibrations. 
The influence of the sun’s rays on a magnet oscillating in a 
void, is to increase the time of a given number of vibrations ; 
whilst the are, if the retardation of the rate of vibration be 
small, is not materially affected.” Nearly the same pheno- 
mena occur when bars of copper are vibrated in like manner. 
Mettonr. “Observations et Expériences relatives 4 la théorie 
et 4 Pidentité des agents qui produisent la lumieére et la cha- 
leur rayonnante,” in Journ. des Sc. Phys. de M. Julia de Fon- 
tanelle, t. iv. p. 161. (1836.) In this remarkable paper, which 
was, I think, presented to the Academy of Sciences of Paris, 
the author, after proving that radiant light and heat have two 
distinct causes, or are two distinct effects of one cause, endea- 
vours to separate light completely from heat. His experiments 
succeeded admirably. Absorbing all the heat either of the 
solar rays or an artificial fire, by making the rays pass through 
a system of diaphanous bodies, such as water or blue glass, he 
sueceeded in obtaining pure light. “This pure light,” says 
Melloni, ‘‘ emerging from this system, contains much yellow, 
and possesses moreover a bluish-green tint. It has no action 
whatever on the most delicate thermometer, even when con- 
densed by a lens until it is as brilliant as the direct rays of the 
sun.” This pure light has therefore all the properties hitherto 
recognized in ordinary phosphoric light, such as that of the 
glowworm, the Bologna-stone, etc. 
Sturtray. ‘“ Recherches sur la cause ordinaire de la Phosphores- 
cence Marine.” —Wag. de Zoologie de Guérin, 1836. 
BECQUEREL (Ed.). On Phosphorescence after Insolation ; many 
papers in dun. de Chim. Paris. Compare also MORREN, in 
Comptes-Rendus, 1861 and 1862, on the Phosphorescence of 
Gases. 
BEcQUEREL (Pére). Traité d Electricité, t. vi. 
Moreno. Repert. d Optique Moderne. (Paris, 1842.) 
These two authors have quoted several facts relating to Phos- 
phorescence in their large works. 
Araao. “ Notice sur le Tonnerre,” etc., in his @uvres Completes. 
