PHYSIOGRAPHY. 109 



Calcareous Spar. 



in the caves of Virginia and Kentucky. Most of the varieties are so 

 common as to render the mention of their localities unnecessary. 



5. Several varieties of Calcareous Spar are usually employed for vari- 

 ous purposes, partly depending upon their mechanical, partly upon their 

 chemical composition. Those used in sculpture, and in ornamental arch- 

 itecture, are called marble; the more common or coarse varieties are 

 used for the common purpose of building. A peculiar variety of very 

 fine grained, compact limestone, is used for plates in lithography. The 

 best sort is found near Pappenheim and Sohlenhofen in Bavaria. Quick 

 lime is obtained from the calcination of this species. Carbonic acid for 

 chemical purposes, as well as for the impregnation of artificial mineral 

 waters, is obtained from chalk and from marble powder. Chalk is allo 

 used for writing and for whitewashing. Calcareous Spar is likewise a 

 valuable addition in several processes of melting ores, and in producing 

 certain kinds of glass. 



APPENDIX TO CALCAREOUS SPAR. 

 i. Jlrchigonal Carbon- Spar. BREITHAUPT. 



Pon P = 105 0'. 



Cleavage parallel to the primary rhomboid, perfect. 



Hardness (scale of BREITHAUPT) = 4-0 . . . 4-25. 



Sp.gr. = 2.7348, a cleavable fragment from Neue Hoffhung 



Gottes at Bi aunsdorf, west of Freiberg. 

 2-7362, a similar variety, but less cleavable. 

 2-7426, cleavage forms, from Hirnmelsftlrst inFreiberg. 

 2-7485, cleavage forms, very clear and beautiful, from 



the Tuuge hohe Birke in Freiberg. 

 2-7500, dull crystalline fragments, from HimmelsfQrst. 

 Other localities of the Archigonal Carbon-Spar at Freiberg, are the 

 Beschert GlQck and Himmelfahrt mines. Besides, it occurs at Johann 

 Georgenstadt, at Schneeberg in the Erzgebirge, and at Przibram in Bo- 

 hemia; and on the whole is a frequently occurring species. 



ii. Kouphone Carbon- Spar. BREITHAUPT. 



p on P = 105 2' 30". 



Cleavage parallel to the primary rhomboid, perfect. 

 Hardness (scale of BREITHAUPT) =3-75. 

 gp. gr. = 2-6788, cleavage forms, from Kornial-Hole at Trieste, 

 in mountain limestone. 



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