340 Van Name — Crystals of Crocoite from Tasmania. 



A typical specimen of the habit above described is repre- 

 sented by figure 1 * The faces present are the prism m (110), 

 the clinodomes_s (Oil) and w (012), the base c (001), and the 

 orthodome h (101). The crystal from which this drawing 

 was made is 64: mm in length and unusually symmetrical. Its 

 diameter across a prism face is l*6 mm . To represent this crystal 



k ,/ 



therefore in its true proportions the figure should be more than 

 seventeen times the length here shown. Still simpler crystals 

 of this type are terminated by the domes z and h alone. 



Figure 2 was drawn from a slightly more complex crystal 

 which shows, in addition to the forms present on the specimen 

 just described, the prisms <#(210) and/' (120), and the pyramid 



*(iii). 



The crystals represented in figures 3 and 4 are unsymmetri- 

 cally developed, and the relative size of the faces has been as 

 far as possible preserved in the drawings. Figure 3 shows the 

 crystal upon which the new clinodome j (032) was observed. 

 It appears on only one side of the crystal, but the face is well 

 defined, gives a good reflection and can be accurately meas- 

 ured. From the measurements to the two z faces, which 



* In this and all the following figures the plan is rotated through an angle 

 of 18° 26', as shown by the arrow, thus preserving the vertical relation 

 between corresponding points in the plan and the clinographic projection 

 below. This mode of representation has been used in a previous article from 

 this laboratory by Robinson (this Journal, xii, 180, 1901), where its object is 

 further explained. 



