238 



On the Application of Manures. 



far serendum, unde lupimim, aut vicia, aut faba, sublata sunt, et quae 

 terram faciant Isetiorem." 



He also says in another place that a crop of beans enriches the 

 ground like manure^ 



" Solum, in quo sata est, Isetificat, stercoris vice." 



Whatever, therefore^ may be the comparative merits of the 

 ancient and modern systems of husbandry in other respects, it 

 vv^ould seem that in this one at least a vast step has been gained 

 since the days of Virgil and Columella. Nor are we less in ad- 

 vance of these writers in the article of manures, which, no longer 

 limited, as with them, to animal and vegetable matters in a state 

 of decomposition, or to lime and certain kinds of marl, compre- 

 hends at present a great variety of mineral substances with which 

 the ancients were wholly unacquainted. 



Amongst these we may enumerate, 1. phosphate of lime or 

 bone-dust, so useful in the turnip, potato, and grass land of this 

 country; 2. the nitrates of potass and of soda, which are said to 

 increase our crops of wheat and other cereal grasses in a remark- 

 able manner ; 3. barilla, or kelp, which has also been employed 

 with success for corn-crops ; 4. common salt, which is considered 

 beneficial to the same on light soils ; and 5. gypsum, the efficacy 

 of which is admitted in leguminous crops, and will probably be 

 found to extend to others also. 



None of the above manures, it is probable, were known by the 

 ancients, though Virgil recommends nitrum* (which appears to 

 have been carbonate of soda or potass, and not, as commonly 

 translated, saltpetre) mixed with the dregs of oil, as a steep to 

 make the seed-grain swell : 



" Semina vidi equidem multos medicare serenles, 

 Et nitro prius et nigra perfundere amurca, 

 Grandior ut fetus siliquis fallacibus esset," 



and suggests our scattering over the exhausted land ashes, wliich 

 probably derived their fertilizing property in great measure from 

 the gypsum they contain, 



" . neve 



EfFetos cinerem immundum jactare per agros." 



The great advance indeed which has been made within two 

 centuries only in the art of husbandry, may be calculated from 

 this one fact alone, namely, that the population of England in the 

 time of Queen Elizabeth amounted, according to the estimate of 



■* See Beckman's History of Inventions. 



