1864.] CHEMISTRY OF MANURES. 195 



first half of the present century, rises, at two points of time, to 

 sudden and conspicuous eminence. Those significant pinnacle.*! 

 bear date 1829 and 1847. The political catastrophes which 

 followed these two seasons of distress respectively, do not require 

 indication. How far the precursory distress depended on inclement 

 seasons, how far on erroneous husbandry, the reporter is not 

 aware. But he believes that no institutions strike root deeply in 

 a country that is badly farmed. 



Empirical Manures. — From these cursory remarks it will 

 be apparent that manures can only be used with success, when 

 they are applied with judgment and moderation, and with due 

 reference, as well to the nature and condition of the soil to be 

 amended, as to the particular description of the crop to be raised. 

 Empirical mixtures, vaunted as suiting special crops, are likely 

 (even when honestly composed) as often to fail as to succeed, 

 because they are commonly employed, in blind confidence, on all 

 kinds and conditions of soils. So extensively does haphazard pre- 

 vail, as yet, in this matter, that costly ammoniacal salts or composts 

 are often applied, without avail, to fields which a cheap dressing 

 (say with lime or silica) would have fitted to bear a good crop. 

 Nay, in some cases a manure may chance to be efl&cient by the 

 very ingredient employed for its adulteration ; as, for instance, 

 sand-mixed guano by its silica. 



Liebig's Manures. — The hisjtory of Liebig's mineral manure 

 — a mixture of ash-ingredients patented by the illustrious philoso- 

 pher in April 1845,* as the practical embodiment of his theory 

 published five years previously — is too remarkable to be passed 

 in silence here. This manure is stated in the specification of the 

 patent, to be composed of substances " containing the elements of 

 the ashes of the plants to be grown," ground up, and " occasionally 

 mixed with gypsum, calcined bones, silicate of potash, magnesian 

 and ammoniacal phosphates, and common salt " Here appeared, 

 indeed, to be the elements of a restorative, well adapted to renew, 

 in conformity with theory, the fertility of ash-exhausted soils. 

 Nevertheless this manure, which excited the highest anticipations, 

 and was eagerly tried on fields innumerable, occasioned universal 

 disappointment ; and was everywhere abandoned as a failure. 



* This patent (No. 10,616, April 15, 1845) is granted to J. Muspratt, 

 a» "for a communication from Justus Liebig." 



