112 



HOW CROPS FEED. 



We might give in the same style formulpe for all the 

 minerals noticed in these pages, but for our purposes tJiis 

 is unnecessary, 



Amphibole is an abundant mineral often met with in 

 distinct crystals or crystalline and fibrous masses, varying 

 in color from pure white or gray {tretnoHte, asbestifs), light 

 green {actinolite), grayish or brownish green {anthophyl- 

 lite), to dark green and black {hornblende), according as 

 it contains more or less oxides of iron and manganese. 

 It is a silicate of magnesia and lime, or of magnesia and 

 protoxide of iron, with more or less alkal'ies. 



White. Gray. Ash-gray. Black. 



Gouverneur, Lanark, Cuminington, Brevig, 

 N. Y. Canada. Mass. Norway. 



Rammelsberg. T. S. Hunt. Smith & Brash. Plantamour. 



57.40 

 a4.69 

 13.89 



0.40 



55.30 

 22.50 

 13.36 



6.30 



trace 



0.40 

 0.80 

 0.25 

 0.30 



50.74 

 10.31 

 trace 



as. 14 



1.77 



0.54 

 trace 

 3.04 



46.57 

 5.88 

 5.91 



24.38 

 2.07 



3.41 

 7.79 

 2.96 



Leekgreen. 

 Waldheim, 



Saxony. 



Kuop. 



58.71 



10.01 



11.53 



Silica, 

 Magnesia, 

 Lime, 

 Protoxide of 



iron, 

 Protoxide of 



manganese, 

 Alumina, 

 Soda, 

 Potash, 

 Water, 



Pyroxene is of very common occurrence, and consider- 

 ably resembles hornblende in colors and in composition. 



Green. Black. Black. 



Lake Orange Co., Wetterau, 



Cliamplain. N. Y. 



Seybert. Smith & Brush. Gmelin. 



1.52 

 12.38 



0.50 



White. Gray- White. 

 Ottawa, Batliurst, 

 Canada. Canada. 

 T. S. Hunt. T. S. Hunt. 



