CALCAREOUS MANURES— PRACIICE. 69 



but the reader at least cannot be mistaken in this, that the ultimate effect 

 of every application of lime must be to make the soil more calcareous ; 

 and to thatpause solely are to be imputed all the long-continued beneficial 

 consequences, and great profits, which have been derived from liming. 

 But excepting this one point, in which we cannot be misled by ignorance 

 or want of precision, the mass of writings on lime, as well as on calcareous 

 manures in general, will need mucii sifting to yield instruction. The opi- 

 nions published on the operation of lime are so many, so various, and so con- 

 tradictory, that it seems as if each author had hazarded a guess, and added 

 it to a compilation of those of all who had preceded him. For a reader of 

 these publications to be able to reject all that is erroneous in reasoning, and 

 in statements of facts— or inapplicable, on account of difference of soil, or 

 other circumstances— and thus obtain only what is true, and useful— it 

 would be necessary for him first to understand the subject better than 

 most of those whose opinions he was studying. Indeed it was not possible 

 for them to be correct, when treating (as most do) of liwe as one kind of 

 manure, and every different form of the carbonate of lime as so many 

 others. Only one distinction of this kind (as to operation and effects) 

 should be made, and never lost sight of— and that is one of substance, still 

 more than of name. Pure or quick-lime, and carbonate of lime are ma- 

 nures entirely different in their powers and effects. But it should be re- 

 membered that the substance that was pure lime when just burned, often 

 becomes carbonate of lime before it is used, (by absorbing carbonic acid 

 from the atmosphere,) — still more frequently before a crop is planted — and 

 probably always before the first crop ripens. Thus, it should be borne in 

 mind that the manure spoken of as liine is often at first, and always at a 

 later period, neither more nor less than calcareous earth ; that lime, which 

 at different periods is two distinct kinds of manure, is considered in agri- 

 cultural treatises as only one; and to calcareous earth are given as many 

 different names, all considered to have different values and effects, as there 

 are different forms and mixtures of the substance presented by nature. 



But, however incorrect and inconvenient the term mai'l may be, custom 

 has too strongly fixed its application for any proposed change to be adopt- 

 ed. Therefore, I must submit to use the word marl to mean beds oi fossil 

 shells, notwithstanding my protest against the propriety of its being so ap- 

 plied. 



The following experiments are reported, either on account of having 

 been accurately made and carefully observed, or as presenting such results 

 as have been generally obtained on similar soils, from applications of fossil 

 shells to nearly six hundred acres of Coggins Point farm (made before 

 1830.) It had been my habit to make written memoranda of such things ; 

 and the material circumstances of these experiments were put in writing 

 at the time they occurred, or not long after. Some of the experiments 

 were, from their commencement, designed to be permanent, and their re- 

 sults to be measured as long as circumstances might permit. These were 

 made with the utmost care. But generally, when precise amounts are not 

 stated, the experiments were less carefully made, and their results reported 

 by guess. Every measurement stated, of land or of crop, was made in 

 my presence. The average strength of the different marls used was ascer- 

 tained by a sufiicient number of analyses; and the quantity applied was 

 known by measuring some of the loads, and having them dropped at regular 

 distances. At the risk of being tedious, I shall state every circumstance sup- 

 posed to affect the results of the experiments ; and the manner of descrip- 

 tion, and of reference, necessary to use, will require a degree of attention 

 that few readers may be disposed to give, to enable them to derive the full 



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