Feb. 1900. New Mineral Occurrences — Farrington. 225 



crystals which occur on a piece of the quartz gangue common at 

 the mine. With the caledonite crystals are associated crystallized 

 cerrusite, massive galena, linarite, and wulfenite. One of the crys- 

 tals of caledonite is of good size, being 5 mm. in length in the 

 direction of the vertical axis, and 3 mm. in length in the direction 

 of the macrodiagonal axis. The other crystals are smaller. All 

 are developed prismatically in the direction of the brachydiagonal 

 axis, and are attached by its extremity. The crystals are of a deep 

 bluish-green color and transparent. They are penetrated to some 

 extent by cerrusite, which shows as darker spots when seen under 

 a lens. These portions also turn brown when fragments of the 

 mineral are heated in the closed tube. Other pyrognostic charac- 

 ters of the mineral, noted by the writer, which may be added to 

 those given by Dana, are: In the closed tube it decrepitates, becomes 

 black and opaque, and gives off water. Fuses easily B. B. with 

 intumescence to a black globule. 



The crystals were fairly well suited for goniometric measure- 

 ment, and the following forms were found, the position and letter- 

 ing being that given by Dana: 



b (010) x (201) s (223) 



c (001) / (012) t (221) 



m (no) e (on) 



The development of the different crystals was found to be qifite 

 constant, the prominent forms being c, b, m and s. The most per- 

 fect crystal was considerably striated parallel with the direction of the 

 brachydomes, also in the direction of the zone of the pyramids and 

 prism. Owing to these striations but few really accurate measure- 

 ments could be obtained, but a few were secured which are of inter- 

 est as supporting the correctness of the ratios obtained by Busz* 

 from a study of the caledonite of Leadhills. The following are the 

 measurements which it was possible to make with accuracy, and 

 for comparison are given the values as calculated by Busz: 



Measured. Calculated. 



d:m = (oio):(iio) 47° 26' 47 2.5' 30' 



W.;;/"'=(lI0):(lI0) 85° 12' 85° 9' 



s:s'" =(223): (22$ 66° 35' 66° 30' 34* 



^/jr=(ooi):(2oi) 71 52' 71° 53' 



X :x'=(20\)\ (201) 36 15' 36 14' 



The crystals were carefully studied also in the hope that some 

 measurements might be found which would throw some light on the 



*Neues Jahrbuch fur Min. Geol. u. Pal. iSqs, Band I, />. in. 



