MANURES. 133 



under -water, as a fertilizer of the soil — so that the use of peat 

 and mud from swamps and ponds is no new discovery. He 

 also recommends the growing of and the ploughing in of green, 

 leguminous crops as a manure, remarking, that they " enrich the 

 soil as much as dung." 



Virgil, -who lived from seventy to nineteen years before Christ, 

 -wrote concerning the advantages to be gained by a rotation of 

 crops ; recommended nitrum,not saltpetre, as many translate, but 

 the carbonate of soda, or of potash, mixed with the dregs of oil, 

 as a preparation for swelling seed grain before planting ; sug- 

 gesting the advantage of scattering ashes over exhausted soils 

 — thus indicating no slight knowledge of the methods of arti- 

 ficial fertilization then known ; speaking not only of ordinary 

 manure, but of special manures, such as pumice stone, shells, 

 Arc. Pliny, who "wrote about one hundred years later, says, 

 " There are many kinds of manure, and the thing itself is very 

 ancient." Varro, one of the most learned men of Some, who 

 lived about one hundred years before Christ, was so minute in 

 his enumeration of animal manures as to mention the dung of 

 blackbirds, thrushes, and other birds kept in aviaries. Cato, 

 Theophrastus, and Columella display a knowledge of compost 

 manures that would be creditable to American farmers of the 

 eighteenth century — occasionally .throwing out suggestions that 

 would do credit to a Massachusetts or New York farmer even, 

 of the present day. 



The Greeks and Romans very generally, at the commence- 

 ment of the Christian era, associated the ideas of successful 

 husbandry with the careful accumulation of manures and their 

 liberal use. They considered the application of manure as 

 one of the principal operations of agriculture, and placed it 

 next to ploughing. They were so sensible of the advantages 

 arising from the manuring of their fields that they were very 

 careful in finding out and collecting all such things as were 

 found proper for the purpose. They carefully gathered the 

 dung of their cattle — littered them with straw or stubble, which 

 they mixed with the droppings of the animals — collected all 

 kinds of ashes — different kinds of earth — burned trees, shrubs 

 and stubble in their fields for the ashes — and frequently sowed 

 pulse — not cereal grains — to plough in as a green manure. " You 



