304 BOARD OF AGRICULTURE. 



rect or superficial experiment and observation, and must, it 

 seems to me, be abandoned. Experiment and observation 

 have convinced me that nitric acid and ammonia are essential 

 and natural constituents of the atmosphere, and of so much 

 importance, and so considerable in amount, that by no means 

 can they be made to take a secondary place in any estimate 

 of the sources of nitrogen in soils. 



Quite early in my farm experiments, before science had 

 shed so great light upon the chemistry and physiology of 

 plant-growth, I was perplexed to understand how it hap- 

 pened that the quantity of nitrogen removed in a series of 

 crops was much greater than that contained in the manures 

 employed, and this, too, when percolating rains and drainage 

 were carrying away no inconsiderable quantity. Analysis 

 proved that nitrogen was present in large quantities in some 

 uncultivated, or virgin, soils on my farm ; and also it was 

 found in considerable amounts in the swamp-muck contigu- 

 ous to my uplands, — areas which had never been cultivated, 

 or received a particle of manure from any source. It became 

 not only evident that nature has hidden sources of supply, 

 but that in some way a remarkable equilibrium is main- 

 tained between want and supply, without the husbandman's 

 intervention. 



Experiments upon fields, cropping without supplying nitro- 

 genous manures, carried on over a period of fifteen years, gave 

 crops of the cereals in diminished amounts. The soil at 

 the end of that period afforded, upon analysis, evidence of the 

 presence of nitrogen, although the quantity removed in the 

 crops was much greater than was contained in the soil at 

 the commencement of the experiments. This proved that 

 somehow, from somewhere, nitrogen was spontaneously fur- 

 nished in the ordinary processes of nature. 



The amount of nitrogen returned to the soil in the hus- 

 bandry of the early settlers in this country was really very 

 small. The manures they produced from their animals were 

 so slovenly cared for (being exposed to rains and snows, and 

 allowed to drain away into marshes and ditches), that they 

 were of small nitrogenous value when used in the field. They 

 could not, indeed, be of high value when well protected, as 

 the grasses upon which the animals were fed were of a low 

 order and of inferior quality. The virgin soils, when well 



