EARLY AGRICULTURAL WRITERS. 47 



greatest abundance, as ammonia and nitric acid. Prior to 

 his researches, it was known that nitrogen was not absorbed 

 free and uncombined from the air ; but much confusion ex- 

 isted as to the exact sources from which it was obtained, and 

 the methods of its appropriation by plants. 



The earthy or inorganic substances in plants were detected 

 by the early chemists ; but as regards their importance and 

 office, or how they were derived, were matters very imper- 

 fectly understood. It was supposed for a long time that 

 lime, silica, iron, &c., were accidental constituents of plants, 

 and that the atoms were carried into the structure by the 

 ascending sap, and that the plants would be better without 

 them. It was impossiljle for these zealous investigators, 

 working in imperfect light and with rude apparatus, to com- 

 prehend the great truth that the inorganic constituents of 

 plants are absokitely essential to their development, and 

 that growth is retarded in their absence. 



In the last century and in the first part of the present, 

 numerous writers upon agriculture appeared, not only in 

 England, France, and Germany, but also in our own 

 country. The great struggle which occupied the time and 

 thoughts of our forefathers was that of subduing the rocky, 

 forest-covered lands of New England, and they had little 

 time to devote to what are now called " crop experiments," 

 or " fancy farming." The clergy seem to have been about 

 the onl}^ class who had leisure to think or read much, and 

 they had topics enough for study in the new world in which 

 they were located. The great problem, how to increase the 

 productiveness of the new fields laid open to the sunlight 

 by the axe did not escape their attention ; and sermons and 

 essays were written and delivered, bearing upon agriculture, 

 some of which exhibit a large degree of intelligence and 

 sagacity. The best among them was a New-England clergy- 

 man, the Rev. Jared Eliot, M.A. His little volume, " Es- 

 says upon Field-Husbandry," was printed in Boston in 1760, 

 and is distinguished for most excellent good sense and a 

 knowledge of the practical duties of the husbandman. He 

 is not pretentious, and lays no claim to knowledge other 

 than what he has obtained by experience : consequently the 

 reader is not troubled with many absurd speculations, such 

 as characterize most of those who wrote upon agriculture 



