INFRA-RED REFLECTION SPECTRA. 



and is no doubt to be attributed to the variable composition of the 

 mineral. 



DEWEYUTE (H4Mg*(SiOO+4H a O). 



(Curve a, fig. 69.) 



This mineral has a complex region of selective reflection extending 

 from 9.5 to 1 1 /A. There are maxima at 9.65 and 10.5 /*. 



o ^0 



IO 



CL, 



56 789/0 



FIG. 69. Deweylite(a); Apophyllite. 



APOPHYLLITE 



(Cleavage parallel to c, fig. 69.) 



There is the usual region of reflection common to the silicates. There 

 are maxima at 9.15 and 



SODIUM METAPHOSPHATE (NaPO 3 ). 

 (Curve a, fig. 70.) 



There is a single band at 8.0 ^ which is harmonic with the band at 4 /*. 

 In other regions the reflection compares with glass and the vitreous sub- 

 stances examined. 



6 733 IO // 



FIG. 70. Sodium metaphosphate (a); Tourmaline. 



TOURMALINE 



(Curve b, fig. 70.) 



The reflection was formed from a natural crystal face. There are 

 maxima at 7.5, 8.0, 9.2, 9.7, 10.2, and 10.7 //,. 



