MINEKALOGY. ^59 



to the already long catalogue for the two species, aud others that are 

 lot certain. He also distinguishes between the charactenst.c orrns ot 

 pvraroynte and pH)nstite, not often atten.pted before, and develops 

 the hemimorpliic nature of the two species. 



A study of some specimens of polianite from Flatten, Bohemia,^ has 

 led to the interesting conclusion that the anhydrous MnO, crysiallizes in 

 the tetraoonal system and is isomorphons with rutile (TiO,) cassiterite 

 (SnO.) and zircon (SiO., ZrO.). The fact that the hard, gray n.anganese 

 ore, polianite, was distinct from the soft pyrolusite was long ago insisted 

 upon by Breithaupt, and his view is thus fully sustained. Flint has 

 extended his ea.iier crystallographic studies and has given valuable 

 contributions on scolecite, braunite, hausmannite and otli.r spec.es 

 from Sweden. The crystals of rutile,^ apatite, and beryl, .> Alexand. 

 dounty, North Carolina, are described by Hidden and W as nn,ton .nd 

 shown to have a number of interesting features. Some of the species ot 

 the chrysolite group have been studied by Bauer^ and the relation be- 

 tween their forms and composition brought out. The species especially 

 considered are chrysolite, hyalosiderite, and the magnesium silicate 

 forsterite. Crvstals of kaolinite,^ rarely obtained in n form allowing o 

 study, have been described by Allan Dick and their form measured and 

 figured by H. Miers. A monoclinic parameter is assigned to them, viz : 



a:h : e :=0.5748 : 1 : 4.7267; /i=8io H' 



The kaolinite from Colorado"^ was recently referred to the tricliuic 

 system of Reusch on the basis of an optical examination. The subject 

 of the <;rystallization of ullmannite has been reviewed by Klein and it 

 is shown that both kinds crystallizing in the pyritohedral and tetrahe- 

 dral divisions of the isometric system are identical in composition, as 

 proved by analyses by Jannasch. An inaugural address by Herschenz 

 gives an account of the Harz barite, with a number of new forms Du- 

 sing^ adds many other new planes for crystals of various ocalities ; 

 many of them siem to be vicinal planes. The inexhaustib e species 

 epidote has been taken up anew, the Swedish mineral oy Fhnk « tha 

 from the Austrian Alps by Granzer,^ and again by Zimanyi," and that 

 from Elba" by Artini. The result of these memoirs is to add a number 

 of new forms to the already very long list. The absorption phenomena ot 

 epidote have been studied by Eamsay.'^ Becke^^ continues a former line 

 of investigation in describing the etching figures on pyrite, sphalerites, 



>Amer. Jouru. Sci., 1888, vol. xxxv, ' «Bib. Sveusk.Vet. Ak. Hamll.. vol. xii, 



243, 



^- , -f,. ^Mcin. Accad. Liucic, IrfST, vol. iv, 



^lUd., l«8T,vo . xxxni p. oOl. ^^^^^^^^^ ^^ 



^Jabrb. Mm., 188., vol. i, 1. ^.^. ; ^^^ .,^51. 



- f ri'"^-' 'Zt/n ^cT' " Faiat^lni K..l.n;, vol. xvxu. 443. 



' » ; iro""' '"''•'"'•"'''• .^Zeitschr. Kryst.. vol. xni, 97. 

 'Zeitschr. Kryst., vol. Xl\ , 4&l. t 



