510 Kraus and Goldsberry — Chemical Composition of 



as shown in fig. 1, indicates the symmetry of the hexocta- 

 hedral (holohedral) class of the cubic system. The lower por- 

 tion of this crystal was subsequently sacrificed for the chemical 

 analysis. 



Specimen 2. — The following forms were noted : (100), (211), 

 (322), (133), (522), and (533). The faces were not nearly as 

 well developed as on specimen 1. Due to an oscillatory 

 development of the various forms, tetragonal pyramids were 

 built up on the faces of the cube, whereas trigonal pyramids 



Fig. l. 



were formed on the corners of the same. The cube faces are 

 the largest on the crystal, the others being usually quite small. 

 The faces of the cube were dull and gave rather poor reflec- 

 tions. The signals obtained from the faces of the other forms 

 were, however, sufficiently good to establish their identity. 

 Some of the faces of the tetragonal trisoctahedrons were 

 striated as shown in fig. 1. 



Specimen 3. — This is a small crystal aggregate about l*25 cm 

 in length. The individual crystals showed the following- 

 forms: (100), (211), (322), (433), (522), and (533). Of the 

 various forms, which were developed, those of the cube are the 

 largest. 



Specimen Jp. — This was a crystal aggregate measuring several 

 centimeters in length and made up of small, well developed 

 cubes. The entire specimen was sacrificed for the chemical 

 investigation. 



In general there was a close agreement between the averages 

 of the observed readings and the calculated values for the dif- 

 ferent angles, as is shown in the following table : 



