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 deadness 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 ftrom 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. Reversing 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 



