54 



COLORADO FERBERITE AND THE WOLFRAMITE SERIES. 



f{ 1.0.11}, the only negative dome observed on any of these crystals, 

 was first noted by Groth and Arzruni and is verified by finding it 

 on three of these crystals. The reflections were, however, very poor, 

 owing to the rounded and striated character of the faces. For com- 

 parison the original measurement of Groth and Arzruni is added to the 

 table below. The p angle, as here given, is equal to (001 AT.0.11) 

 (90-/?)[ = 28']. The calculated values of p for {T.0.10} and 

 {T.0.12} are also added, and though my own measurements would 

 agree better with these two forms, it is preferable, on account of the 

 poor quality of the reflections, to assign them to the known form 



Measurements o 



As measured by Groth and Arzruni, p=4 59J'. 

 p calculated for {1.0.10}=5 32'. 

 p calculated for {1.0.12}=4 32'. 



The form ^{T.O.ll} is illustrated in figures 23 and 24 (p. 66). 



p {2 14} was first described by Moses on a crystal from Boulder 

 County, Colo. It was also noticed by me as narrow faces on crystals 

 19, 29, and 30 (see figs. 19 and 29, pp. 64, 67), lying in the zone c(001) : 

 Z(210). The faces gave poor reflections. The angles measured by 

 Moses are also shown in the table below. 



The form was measured on crystal 19 with the following result: 



Measurements of p {214}. 



In addition to the measurements of p{214} given above, the form 

 was identified on crystals 29 and 30. These crystals, however, were 

 so incompletely developed that they could not be well placed in 

 polar position. The angle between p(214) and Z(210) was therefore 

 measured, with the following results: 



Measurements of angle p(214): 1(210). 



Crystal 29 58 39 



Crystal 30 60 05 



Calculated.. -.60 05 



