52 FRAGMENTS OF SCIENCE. 
burned, and refractory ones were raised to a white heat, by 
the concentrated invisible rays. Thus, by exalting their 
refrangibility, the invisible rays of the electric light were 
rendered visible, and all the colors of the solar spectrum 
were extracted from utter darkness. The extreme rich- 
ness of the electric light in invisible rays of low refrangi- 
bility was demonstrated, one-eighth only of its radiation 
consisting of luminous rays. The dead ness of the optic 
nerve to those invisible rays was proved, and experiments 
were then added to show that the bright and the dark rays 
of a solid body, raised gradually to incandescence, are 
strengthened together; intense dark heat being an invari- 
ble accompaniment of intense white heat. A sun could 
not be formed, or a meteorite rendered luminous, on any 
other condition. The light-giving rays constituting only 
a small fraction of the total radiation, their unspeakable 
importance to us is due to the fact that their periods are 
attuned to the special requirements of the eye. 
Among the vapors of volatile liquids vast differences 
were also found to exist, as regards their powers of absorp- 
tion. We followed various molecules from a state of 
liquid to a state of gas, and found, in both states of aggre- 
gation, the power of the individual molecules equally 
asserted. The position of a vapor as an absorber of 
radiant heat was shown to be determined by that of the 
liquid from which it is derived. Eeversing our conceptions, 
and regarding the molecules of gases and vapors not as the 
recipients but as the originators of wave-motion; not as 
absorbers but as radiators; it was proved that the powers 
of absorption and radiation went hand in hand, the self- 
same chemical act which rendered a body competent to 
intercept the waves of ether rendering it competent, in the 
same degree, to generate them. Perfumes were next sub- 
jected to examination, and, notwithstanding their extra- 
ordinary tenuity, they were found vastly superior, in point 
of absorptive power, to the body of the air in which they 
were diffused. We were led thus slowly up to the exami- 
nation of the most widely diffused and most important of 
all vapors the aqueous vapor of our atmosphere, and we 
found in it a potent absorber of the purely calorific rays. 
The power of this substance to influence climate, and its 
general influence on the temperature of the earth, were 
