MISCELLANEOUS COMPOUNDS. 



59 



(From Parker Shaft, Franklin, New Jersey. Semi-transparent; f = o.o8 mm. 



Curve c, fig. 45.) 



The sample was a mixture of calcite and willemite. The section 

 examined was quite pure willemite. The curve shows a depression at 

 2.9 /A and bands at 5.9 and 6.75 p.. 



50/ c 



O 



2 3 4 S 6 



FIG. 45. Garnet (a); Monazite (d) ; Willemite. 



a 



COLLODIUM (C,H T O 2 (ONO a )). 



(f = o.oi mm. Curve a, fig. 46.) 



The film of this compound was made by painting a layer of the com- 

 mercial "collodion" over a rectangular hole, 4 by 10 mm., in a piece of 

 cardboard. After the volatile solvent had evaporated the film was 

 dried over P 2 O 5 for a week. 



The constitution of this compound is unknown. It will be noticed 

 that the transmission curve is entirely different from those rich in CH 2 

 or CH 3 groups or from those found for the benzine derivatives. 



There are absorption bands at 1.65, 2.9, 3.5, 6.05, 7.3, 7.85, 8.7, 9.2, 

 9.5, 10.0, 10.8, 11.7, 12.3, 12.7, and 13.6^. 



AMMONIUM CHLORIDE (NH 4 C1). 

 (Translucent; t = o.6 mm. Curve b, fig. 46.) 



Section made from a lump of the commercial material. It is very 

 opaque, with bands at 1.65, 2.2, and 2.95 /x, the latter being in the region 

 where NH 2 compounds and NH 3 have a band. Porter (loc. cit.) found 

 a reflection band at 344/*. 



