gg CALCAREOUS MANURES-- PRACTICE. 



wood ashes, or lime— though the two last have other qualities Ijesides the 

 calcareous. During the short time that lime can remain quick or caustic, 

 after being applied as manure, it exerts (as before stated) a solvent power, 

 sometimes beneficial and at others hurtful, which has no connexion with its 

 subsequent and permanent action as calcareous earth. 



These natural deposites of fossil shells arc commonly, but very impro- 

 perly, called marl. This misapplied term is particularly ol)jectionable, be- 

 cause it induces erroneous views of this manure. Other earthy manures 

 have long been used in England under the name of marl, and numerous 

 publications have described their general effects, and recommended their 

 use. When the same name is given here to a different manure, many per- 

 sons will consider both operations as similar, and i^erhaps may refer to 

 English authorities for the purpose of testing the truth of my opinions, and 

 the results of my practice. But no two operations called by the same 

 name can well differ more. The process which it is my object to recom- 

 mend, is simply ^/ie a2Jplication of calcareous earth in any forimvhatever, 

 to soils tuanting that ingredient, and generally being quite destitute of it ; 

 and the propriety of the application depends entirely on the knowing that 

 the manure contains calcareous earth, and what proportion, and that the 

 soil contains none. In England, the most scientific agriculturists apply the 

 term mcirl correctly to a calcareous clay of peculiar texture; but most 

 authors, as well as mere cultivators, have used it for any smooth soapy 

 clay, which may or may not have contained, so far as they knew, any pro- 

 portion whatever of calcareous matter. Indeed, in most cases, they seem 

 unconscious of the presence as well as of the importance of that ingre- 

 dient, by their not alluding to it when attempting most carefully to point out 

 the characters by which marl may be known. Still less do they inquire into 

 the deficiency of calcareous earth in soils proposed to be marled— but 

 apply any earth which either science or ignorance may have called marl, 

 to any soils within a convenient distance— and rely upon the subsequent 

 effects to direct whether the operation shall be continued or abandoned. 

 Authors of the highest character, (as Sinclair and Young, for example,) 

 when telling of the practical use and valuable effects of marl, omit giving 

 the strength of the manure, and generally even its nature— and in no in- 

 stance have I found the ingredients of the soil stated, so that the reader 

 might learn what kind of operation really was described, or be enabled to 

 form a judgment of its propriety. From all this, it follows that though 

 what is called marling in England may sometimes (though very rarely, as 

 I infer,) be the same chemical operation on the soil that I am recommending, 

 yet it may also be either applying clay to sand, or clay to chalk, or true 

 marl to either of those soils ; and the reader will generally be left to guess, 

 in every separate case, which of all these operations is meant by the term 

 marling. For these reasons, the practical knowledge to be gathered from 

 all this mass of written instruction on marling will be far less abundant 

 than the inevitable errors and mistakes. The recommendations of marl 

 by English authors, induced me very early to look to what was here called 

 by the same name, as a means for improvement. But their descriptions of 

 the manure convinced me that our marl was nothing like theirs, and thus 

 actually deterred me from using it, until other and more correct views in- 

 structed me that its value did not depend on its having " a soapy feel," or 

 on any admixture of clay whatever. 



Nevertheless, much valuable information may be obtained from these 

 same works, on calcareous manure, or on marl, (in the sense that term is 

 used among us) — but under a different head, viz., lime. This manure is gene- 

 rally treated of^ with as little clearness or correctness, as is done with marl ; 



