ZIRCONIUM OXIDE. 



109 



which remains superposed upon the continuous background even at a 

 bright yellow heat, corresponding to a temperature of about 1400 . 



2 3 4 5 6 



Fig. 77. Zirconium oxide. 



This series of energy curves is one of the best illustrations yet recorded 

 of the gradual shift of the maximum of intensity of emission toward the 

 short wave-lengths with rise in temperature. On an energy consumption 



