24 



INFRA-RED REFLECTION SPECTRA. 



Strontianite (SrC0 3 ). 

 (Curve a, fig. 17.) 



The band at 6.68 /* is not resolved even with the large dispersion of 

 fluorite. The band is symmetrical, as previously found in fig. 2. 



Witherite (BaC0 3 ). 

 (Curve b, fig. 17.) 



The pair of bands is somewhat better resolved, with maxima at 6.7 

 and 6.97 //, respectively, the same as was found in the previous examination 

 of this same specimen (see fig. 2). The reflecting power is slightly lower 



4-d 



30 



(J 



0)20 



CC 



10 



2 .4 -6 .8 7 .2 



Fig. 17. Strontianite (u); Witherite. 



7.4/U 



but that is to be attributed to the difference in the adjustment, i.e., the faces 

 of the comparison mirror and of the substance may not have been in the 

 same plane. As a result they would not reflect the same part of the image 

 of the glower upon the spectrometer slit. This is of minor importance 

 since we are not concerned with the absolute reflecting power. 



On a subsequent page it is shown that an emission band of Adularia 

 occurring at 2.9 p. is shifted to 3.2 fi in the absorption spectrum of the crys- 

 talline material. Using polarized energy, the reflection bands of the car- 

 bonates depend upon the direction of vibration of the incident energy. 

 The author therefore hopes to investigate water solutions to learn the be- 

 havior of these reflection bands, using polarized radiation. 



