18 ♦introduction. 



tity of wheat in the United States is 91,642,957 bushels an- 

 nually, worth, at one dollar per bushel, $91,642,957; of 

 other grains, oats, rye, corn, etc. 550,299,557 bushels, worth 

 upon an average at least fifty cents per bushel, which would 

 amount to S275, 149,778 ; of potatoes, 113,183,619 bushels, 

 worth, at twenty cents per bushel, $^22,6^.6,'/ 23, giving a to- 

 tal value of cultivated crops of 8389,429,459. But this is 

 but a small part of all the productions. The whole agricul- 

 tural produce of the country, including the domestic animals, 

 must be worth more than twice this amount. A late writer 

 has estimated the total value of the products of the country 

 including manufiictures, at 1200 millions of dollars annually; 

 the manufactured products being less than 200 millions. 

 '' There is no profession," says Liebig, " which can be com- 

 pared in importance with that of agriculture, for to it belongs 

 the production of food for man and animals ; on it depends 

 the welfare and development of the whole human species, 

 the riches of states and all commerce. There is no other 

 profession, in which the application of correct principles is 

 productive of more beneficial effects, or is of greater and more 

 decided influence." Compared then with this interest, all 

 others are of minor importance. 



Such is the incalculable interest involved in the art, that it 

 becomes a question of primary importance, what aid it may 

 derive from the physical sciences. 



It can be shown I think, in very few words, that botany, 

 chemistry, mineralogy and geology, furnish us with many 

 principles which may be applied to this art to render it more 

 perfect, and more productive. The laws of nature are con- 

 stant and unchanging in their action. If we can learn what 

 these laws are, as they stand related to the vegetable kingdom, 

 we may receive important aid from being able to control 

 them, or to bring our efforts to coincide with their agency. 



I. Mineralogy and Geolo(jy afford aid to agriculture 

 chiefly by enabling us to determine, by the inspection of the 



