434? DOMAIN V. CALCAREOUS. 



with this material ; which, as already mentioned, 

 seems the lapis Troicus of the ancients. The 

 Egyptian konite, which forms a whole chain of 

 mountains, extending from Cairo and the front 

 of the pyramids, far to the south, is sometimes 

 Simple, and sometimes contains shells, chiefly 

 nummulites, which, when cut across, resemble 

 grains of wheat or barley; whence the fable of 

 the ancients, that the workmen employed re- 

 ceived such vast quantities of grain, that much 

 of it was left and petrified. Some of the most 

 ancient edifices of Persia, Greece, and Italy, 

 are also built with konite; but the ruins of Poes- 

 tum, and the temple of Agrigentum, are of cal- 

 careous tufa. 



In general, writers on mineralogy, while they 

 are often occupied with laborious trifles, seem 

 strangers to the chief object, which is the utility 

 of the substances. Brongniart, the director of 

 the porcelain manufacture at Sevres, and accus- 

 tomed to consider objects as adapted to the pur- 

 poses of human life and manners, has sometimes 

 deviated into utility; and his account of the 

 konite thus becomes interesting. 

 Brongniart's This substance is the chaux carbonatfc 



account. 



grossiere of Haiiy, and is commonly called pierrc 

 a bdtir, pierre de taille, and moellon. The tex- 

 ture is often loose, and the grain coarse. 



