304 LINN^US. 



Class I. Petr^ or Stones, or, as modern geologists 

 would say, Rocks. 



Steril stones, originating from an earthy principle by 

 cohesion ; simple, as being destitute of salt, sulphur, or 

 mercury ; fixed, as not being intimately soluble ; similar, 

 as consisting of particles united at random. 



Order I. Humos^e. Deposited from vegetable earth, 

 combustible and burning to cinders, their powder harsh 

 and light ; as roofing-slate. 



Order II. Calcari^. Originating from animal earth ; 

 penetrable by fire, and becoming more porous, their pow- 

 der mealy ; and when burnt, they fall into a fine powder ; 

 as limestone, marble, gypsum. 



Order III. Argillace^. Originating from the vis- 

 cid sediment of the sea, becoming harder and stifFer in 

 the fire, their powder unctuous before exposure to fire ; 

 as serpentine, asbestus, mica. 



Order IV. Arenat^. Originating from precipitation 

 caused by rain-water, when struck with steel emitting 

 sparks, very hard, their powder rough and angular like 

 bits of glass ; as quartz, jasper, flint. 



Order V. Aggregate. Originating from a mixture 

 of the foregoing, and therefore participating their consti- 

 tuent particles; their powder differing accordingly; as 

 granite, puddingstone. 



Class II. MiNERiE, Minerals. 



Fertile stones, originating from a saline principle by 

 crystallization; compound, as produced from a stony 

 substance (of the preceding class), impregnated by salt, 

 sulphur, or mercury, intimately soluble in an appropriate 

 menstruum, and crystalline. 



Order I. Salia, Salts. To be distinguished by the 

 taste, soluble in water ; as rock-salt, alum, borax. 



Order II. Sulfhura, Sulphureous Minerals, Dis- 

 tinguishable by smell, emitting an odour and flaming under 

 the action of fire, soluble in oil ; as amber, naphtha, 

 pyrites. 



