34 



INFRA-RED REFLECTION SPECTRA. 



the rock-salt prism showed only weak maxima at 8 to 10 p.. In a previous 

 study of quartz with a rock-salt prism a narrow, quite intense band was 

 located at 12.5 /*, which had not been recorded by Rubens and Nichols. 

 In the present examination, using grating No. 1, the maximum was found 

 at 2 21' (=12.8//), while with grating No. 2 the maximum was located 

 at 3 20' (=12.5^). In table I are given the maxima of the reflection 

 bands of the minerals studied. 



Table I. Maxima of Reflection Bands. 



Smithsonite, ZnCC>3 



Cerussite, PbC0 3 



Strontianite, SrCOs 



Witherite, BaCOs 



Malachite, CuOC0 2 -H 2 

 Azurite, 3 CuO-2 C0 2 -H 2 . . . 



Dolomite, CaMg (C0 3 ) 2 



Siderite, FeC0 3 



Calcite, CaC0 3 



Aragonite, CaC0 3 



Magnesite, MgC0 3 



Scheelite, CaW0 4 



Zircon, ZrSi0 4 



Wulfenite, PbMo0 4 



Rutile, Ti0 2 



Cyanite, Al 2 3 -Si0 2 



Corundum, A1 2 3 



Topaz (Al-F) 2 Si0 4 : 



Yellow 



White 



Spodumene, LiAl(Si0 3 )2 



Muscovite Mica, H 2 KAl 3 (Si0 4 ) 3 



Cryolite, 3 NaF- A1F 3 



Beryl, Be 3 Al 2 (Si0 3 ) 6 



Quartz: 



Glass 



Crystalline 



6.65 



6.9 



6.68 



6.70 



6.66 



6.65 



6.58 



6.6 



7-05 

 7-25 



6.98 



7-3 

 7-32 

 6-95 

 7-i 



6.4?: 6.5 



7.8? 

 7.8 



6.62 



7.0? 

 6.9 



11. o 

 "75 



10.28 

 i3-5 



10.9 

 11. o 

 10.4 

 10.2 

 6.0 

 9.9 



8.8 



11. 4 



11.6 

 i3-i 



"3 



12.? 



18.4 



i5-i 



10.4 



11. 4 



30.2 



21.25 



16.? 



M 



29.4 



