48 



COLORADO FEBBEEITE AND THE WOLFRAMITE SERIES. 



On crystal 23, the new form, R, lies between 1(210} and <2{S30} as 

 a very narrow face, giving a distinct signal. The faces measured in 

 one-half the prism zone are (010), (110), (210), (810), (100); (010), 

 (TlO), (210), (T5.7.0), (830), (TOO). 



On crystal 31, three faces lying very close together gave good 

 signals, and the measurements showed the presence of the three forms 

 Z{210}, #{15.7.0}, and {940}. 



On crystal 18 a part of the prism zone (see description of {940}, 

 crystal 18) showed the forms #{830}, {940}, #{15.7.0}, and Z{210}. 



In all the three occurrences of R{ 15.7.0} the form is associated with 

 Z{210} and in two of them it lies between Z{210} and {940}. From 

 these facts, as well as the close agreement in measured and calculated 

 values, the form is considered as definite and well established. 



Measurements of * C{ 940 } . 



On crystal 18 the form was one of three faces lying close to Z{210} 

 and between it and a{ 100} . They form alternating narrow faces, but 

 the signals they gave were clear and distinct. The faces were not 

 striated. The prism zone is incomplete, the piece measured being 

 only a fragment of a crystal. The other three forms present in the 

 zone are Q{830}, #{15.7.0}, and Z{210}. 



On crystal 31 the three forms Z{210}, #{15.7.0}, and {940} lie 

 close together and form alternating nonstriated faces similar to those 

 observed on crystal 18. The other parts of the prism zone are not 

 measurable, so that the presence on this crystal of other faces of the 

 last two forms could not be confirmed. 



On crystal 1 the form was noted once as a line face between a(100) 

 and a cleavage face of &(OTO). On other parts of the crystal the 

 form was absent. 



Measurements of *F{ 520 } . 



