AS RELATED TOWEALTH. 97 



rations do not produce their best results at all times 

 in the discovery of minerals. It is to this that at- 

 tention is most directed, and success in this is gen- 

 erally the criterion by which they are judged. 

 Other objects receive attention. They point out 

 general characteristics of soil as derived from cer- 

 tain classes of rocks, discover fertilizers, and thus 

 give important aid to agriculture. They point out 

 proper building materials by the discovery of quar- 

 ries, and clays, cements and paints. Such exam- 

 inations in many cases give important hints in en- 

 gineering, the draining of land, the sinking of Ar- 

 tesian wells, and consequently bear upon the health- 

 fulness and habitableness of large tracts of land. 

 In all these incidental methods, Natural History 

 bestows wealth, without receiving credit from those 

 benefited. 



States have generally shown their wisdom when 

 ordering geological surveys, by connecting with 

 them surveys in every other department of Natural 

 History. The plants, the birds, the fishes, the 

 quadrupeds, and insects have each been deemed 

 worthy of study. Many have sneered at the idea of 



