1889.] NATURAL SCIENCES OF PHILADELPHIA. 185 



From these measurements it follows that the crystal belongs to the 

 isometric system ; the combination being O, oo O ». The faces 

 (g and li) belong to a pentagonal dodecahedron, whose symbol is 

 -." ' because g : b = 24° 30' (uncertain owing to the strongly blur- 

 red condition of the weak reflection ; 20 oo requires 26° 30'). This 

 form should occur, however, in symmetrical pah's of faces. It is ob- 

 served here only in single faces. The upper apex is quite perfect 

 and so is the front apex, yet there is no indication in either case of a 

 companion face. A tetartohedral development must therefore be 

 assumed in this instance. 



Specific gravity = 6.8334 at 24° C. B. B. In closed tube it yields 

 a sublimate of* metallic arsenic. On charcoal it does not fuse until 

 a large quantity of arsenic has been volatilized. Heated with a 

 borax head in the 0. H. on charcoal, a blue glass is obtained for 

 some time, then a brown glass. (Cobalt and Nickel.) 

 The analvsis gave : 



0-9421 ) 



0481 J 0-9902 



0-3185) 



0-1087 - 



0-0413 ) 0-4685 



100-40 

 The atomic ratio therefore : 



(As, S) : (Ni, Co, Fe) = 211:1 

 It is further notable that 



Fe : Co : Ni = 1 : 3 : 9 very nearly. 



2. Xicolite. — This species has been observed only in a few small 

 grains in connection with the following species. It is recognized 

 by the peculiar color. 



3. De Saulesite, a zinciferous variety of Garnierite. — Tins species 

 occurs as a crust and as the filling of the cavities in a deeply purple 

 fluorite. It is associated with Chloanthite in such a manner, that 

 the most probable inference to be drawn is, that the arsenide is not 

 the original, but was crystallized either at the same time or later 

 than the silicate. Chloanthite is disseminated in very minute pris- 

 matic crystals all through the green silicate. This latter is built 

 up loosely in grate-like forms, assuming the texture of certain 

 sponges. The linear, intersecting, cylindroid rods are covered with 

 roughly polyhedral excrescences which seem to be crystalloid bodies. 

 Besides this form, which has been reported for the Algerian Gar- 

 nierite, the green mineral appears less frequently in massive, com- 

 pact, bluish-green bands, bordered by Chloanthite. It resembles in 

 this form certain serpentines, from which, however, its softness readily 

 distinguishes it, The color varies from yellowish-green to bright 



