200 On Manures. 



joining farm-yard, with the addition of an occasional bag of 

 lime. These ponds, to which they give the name of * Pre- 

 6 sidents,' furnish a most valuable manure. 



On a Mixture of Soils. It may be proper to conclude 

 this branch of the subject, with some hints on the advantages 

 derived from a mixture of soils, by which their texture may 

 be greatly improved, and the manures applied to them, may 

 be rendered much more useful. By a proper mixture of 

 light earth, sand, or other coarse and incoherent substances, 

 stiff soils, which water can hardly penetrate, may be so open- 

 ed and subdivided, as to admit freely a quantity of moisture, 

 and other nutritive matters, sufficient for the nourishment 

 of plants ; while light soils, on the other hand, by being in- 

 corporated with clay, are rendered more retentive both of 

 moisture and of manures, and the vegetables produced by 

 them, are enabled to take such a hold of the soil, from 

 their superior tenacity, that they attain much greater perfec- 

 tion. In the most fertile soils, however, sand is the most 

 essential ingredient, to the extent of from 50 to even 60 per 

 cent. The great fertilizing virtue of sand, arises from its 

 allowing both air and water to penetrate to and reach the 

 roots of vegetables, of which they form such essential in- 

 gredients. 



In discussing the subject of manures, attempts have been 

 made by various authors, to arrange these substances in a 

 philosophic manner, and to explain their properties on che- 

 mical principles. In this work, restricted to practical infor- 

 mation, it is proposed to classify them under the general 

 heads of Putrescent ; Calcareous ; Earthy ; Vegetable ; 

 Miscellaneous ; and those mixtures of various substances, 

 known under the name of Composts. 



1. Putrescent Manures ( l65 ). 



These unquestionably are the most important of the 

 classes above enumerated. They not only supply the soil 

 directly with the principal sources of fertility ; but having 

 a tendency to produce a strong germination early, plants 

 have thence a better chance of reaching maturity. Putres- 

 cent substances, being of a nature susceptible of decompo- 

 sition, are ultimately exhausted, when the soil has yielded 

 crops for any course of time. It is necessary therefore to 

 replace them ; and the articles which may be employed for 



