EXPEKIMENT STATION. 63 



tained, which is reported to have nearly equaled stable manure in 

 fertilizing effect. On the other hand, when the wash into the 

 swamp is scanty and from coarse, poor soil, when the vegetation 

 is mere moss or a spare growth of sedge, and when large volumes 

 of water flow through it and leach out its soluble matters, then it 

 would be strange if the muck had any considerable active fertiliz- 

 ing quality. It may, nevertheless, even then, be very serviceable 

 for amending poor, coarse, sandy or gravelly soils, but the amend- 

 ing must be followed up by real "manure" of the appropriate 

 kind. 



Mr, Perkins says further : " Our muck beds are from two to ten 

 feet deep. At the bottom of them we find stone that are quite 

 white and remain so for many years. I can point out in our walls 

 every stone that came from the muck." This interesting state- 

 ment illustrates one of the modes in which swamp muck, as well 

 as stable manure, green crops ploughed under and decaying vege- 

 table matter, generally operate as indirect fertilizers. The white 

 stones observed by Mr. Perkins, differ from those taken out of the 

 arable land or those that originally strewed the surface of much 

 of the higher land simply in one respect. The stones long weath- 

 ered on or m the soil, are colored yellow or brown by compounds of 

 iron, which are constant ingredients of nearly all our rocks. The 

 stones dug out of the muck are white because these iron com- 

 pounds have been dissolved away by the action of the acids 

 which are develojDed in the decay of vegetable matter, and which 

 are essential ingredients of SwamjD Muck. 



The productiveness of unraanured land is kept up by natural 

 processes which libei'ate potash, phosphoric acid, lime, etc., from 

 the stony matter or rock-dust of the soil. Living roots attack 

 this rock-dust by the vegetable acids (oxalic acid) which they 

 contain. Stable manure and swamp muck attack it by the humic 

 acids which they contain and by the carbonic acid of which in their 

 decay they are the constant and abundant sources. These and 

 similar applications, which consist largely of humus or decaying 

 vegetable matters, thus prepare for crops the nutriment of which 

 the soil is the great storehouse, and manure the land by making 

 its own supplies available. 



Mr. Perkins also states in his letter: "I think it remarkable 

 that we can raise the nicest and largest potato crops on our black- 

 est, most mucky soil, and they never rot," 



Since low damp situations are commonly favorable to the potato 



