450 



BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



on the one-circle goniometer, 

 observed : 



On these the following forms were 



Of these two forms (910) and (0.1.14) are new. The angles measured 

 for them on the 1-circle goniometer compare as follows with the 

 calculated angles: 



Calculated Measured 



o / o / 



0.1.14: 0.1.14 10 38 10 36 



910: 910 9 58 9 40 



More recently a few crystals from the locality have been measured 

 on the 2-circle goniometer. Thedrawings, Figures 155-156, have been 

 made from these measurements. The average angles obtained are 

 given in the following table : 



Measurements of anglesite from the Hypotheek mine 



LEADHILLITE (734) 



Monoclinic. 



Sulphate-carbonate of lead, 4PbO.S0 3 . 

 2C0 2 .H 2 0. 



Leadhillite has been identified in small amount in specimens from 

 two mines in Shoshone County. It is probably present more fre- 

 quently in the ores but has been overlooked because of its resemblance 

 to cerusite. 



