NICHOLS. 



THE VISIBLE RADIATION FROM CARBON. 



107 



the acetylene flame. A noteworthy fact exhibited by means of these 

 curves is the relatively rapid increase of intensity in the middle of the 

 spectrum. In passing from 930° to 1055° the brightness of wave 

 length .76//, increases 5.3 times; that of .70^, 7.2 times ; that of .60 /i, 

 13.5 times, and that of .50 ^ only 9 times. We have here the beginnings 

 of a process which becomes more marked in its effects as higher temper- 



7^A 



■(,0, 



'A 





lOOo" /lOO" /iOO" /iOO' 



Figure 19. 



atures are attained. From 1100° upwards it was found much more 

 difficult to obtain satisfactory readings. The carbon rods which I had 

 brought from Paris for this investigation would not stand prolonged 

 heating and it was necessary to replace them frequently. 



