1S36.] 



F A R ftl E R S ' REGISTER. 



285 



ry small portion of the carbonate of lime; its effi- 

 cacy tiierefore cannot be solely attributable to that 

 cause*, and it must possess some otlier property 

 (i-om which its influence upon the land is partly de- 

 rived. This may consist either in the chani^e 

 which its application produces in the texture of the 

 p;round throui^h the mere increase of its bulK', 

 which, by i(s dense and unctuous quality, also adds 

 to the consistence and value of all lio-ht soils; or, 

 by the more perfect combination of the particles of 

 which it is formed, by which its powers are brought 

 into full action, and lime, sand, and clay are each 

 made to bear against each other, and thus aid its 

 mechanical operation on the land. All marl, ex- 

 cept those species which are combined with large 

 portions of iron, sulphur, or deleterious mineral 

 substances, also of ilself affords nourishment to 

 corn and veaetablcs; it must, therefore, be consid- 

 ered as a soil, and when laid upon the land, this 

 addition must necessarily yield a more abundant 

 support to succeeding crops. 



If this view of the subject be correct, it may be 

 assumed, that all kinds of marl which abound in 

 calcareous matter may be considered applicable to 

 every soil to which lime is beneficial; subject, how- 

 ever, to the efiecl which may be also produced by 

 the other portions of their substance when applied 

 to land of a peculiar nature. Thus — as we have 

 already more fially stated in the preceding part of 

 our observations — on light, sandy, and gravelly 

 soils, an advantage is gained by the largequanti- 

 ty of clay which the marl appropriate to such land 

 tisually contains, by rendering ihefti more stiffand 

 impervious to the rain, and therelbre stronger: on 

 wet and heavy lands, on the contrary, as it renders 

 the soil more retentive, unless very great care be 

 bestowed on their drainage, it may occasion per- 

 manent injury; but shell and stone-marl occasion 

 it to become loose and friable. Attention should 

 therefore be paid, not only to the nature of the marl, 

 but to that also of the soil to which it is to be ap- 

 plied; and when a choice of marl can be procur- 

 ed, its earthy portion should differ as widely as 

 possible fiom tliat of the ground upon which it is 

 intended to be laid. 



In fine, marl may be considered as an improver 

 of the soil under so many different circumstances, 

 that it can hardly be recommended m too sfrono- 

 terms; for if it be used with judgment, it adds sta- 

 ple to the soil, improves its quality, and renders the 

 application of [lutrescent manure more effectual. 

 The use which some farmers make of it, however, 

 deserves the highest censure, — ' many of them ta- 

 king repeated crops of crats in the interval of one 

 summer-fiillowfor wheat, by way of cleansino; the 

 land; after which, barley and oafs a^ain, as long 

 as the land will produce anvthinir, until it is at last 

 laid down with ^veeds and conch-cjrass. Such is 

 the view taken of their conduct by the surveyor of 

 Lancashire, where it is very extensively employed, 

 and in which opinion he is b}^ no means singular. 



* Out of twelve specimen? of marl submitted to the 

 inspection of Sir Humphry Davy, eleven were found 

 to contain calcareous earth in various proportions; but 

 the result of many other trials of marls, procured from 

 diflferent parts of the country, and found by farmers to 

 produce an amelioratinf^ effect upon the land, yet 

 proves them to be, in many instances, wliolly deficient 

 in that substance. See the section on 'Marl,' in Hol- 

 land's Survey of Cheshire. 



Vol. IV— 34 



The rotation which he recommends — with refer- 

 ence, of course, to land that is not too strong — is 

 to take one crop ot oafs the spring subsequent to 

 marling; plough the stubble immediately, in order 

 to expose the marl again to the iuHucnce of the 

 frost; fallow, with manure, for turnips — a crop 

 which, under this management, is never known to 

 tail; then barley, clover, wheat, turnips led ofl' 

 with sheep, and barley again, with well-dressed 

 hay seeds, and white clover and trefoil (or a peren- 

 nial ley, or at least lor some years*. Under which 

 manaiiement, poor land may, when properly tilled 

 and duly supplied with putrescent manure, he ren- 

 dered highly exuberant without being in the least 

 degree harassed. 



Jlaalysis of Marl. 



The value of marl, as a manure, must of course*, 

 be referable to the nature of the different kinds 

 employed. It is, indeed, evident that, being in- 

 tended to correct or improve the soil, its constitu- 

 ent parts should be known, and their qualities ex- 

 plained, before any use can be rationally made of 

 it; and, therefore, the more accurately its proper- 

 ties are ascertained, the more confidently may the 

 propriety of its application be determined. Farm- 

 ers, indeed, cannot be expected to be suflicienfly 

 acquainted with chemistry to be able to analyze if, 

 though the most calcareous sorts may be known 

 by means of acids, as applied to lime; or, the 

 common earthy kind, when put into water, will fall 

 to pieces, allowing a considerable portion of sand 

 tofiill to the bottom of the vessel: bj'' which sim- 

 ple tests, they might often derive considerable ad- 

 vantage. Its qualities are, however, more gener- 

 ally taken, by mere practical men, more upon trust 

 derived from the experience of their neighbors 

 than from any actual knowledge of its properties; 

 but although, when thus guided, thcj' cannot go 

 far wrong, yet they may be misled by circumstan- 

 ces of slight a])parcnt diflerence, and, in cases ot 

 new pits being opened, no certain estimate of its 

 eflect can be formed until a complete analysis has 

 been made. This should, indeed, be done in all 

 such instances; for it costs but a trifle, is easily per- 

 formed, and without liaving recourse for the pur- 

 pose to a regular scientific chemist, the object may 

 be attained by application to any intelligent aj^otli- 

 ecary, by furnishing him with the following account 

 of the modes of procedure: — 



The ingredient of marls, on which their fitness 

 for agricultural purposes depends, is the carbonate 

 of lime. It is owing to the presence of this earth 

 that marls effervesce on the addition of acids, 

 which is one of their distinguishing characters: to 

 ascertain which — 



' Let the marl l-.e put into a glass partly fiilled 

 with water, which will expel a portion of air con- 

 tained mechanically in the marl, and thus obviate 

 one source of fiillacy. Wlicii the marl is thor- 

 oughly penetrated by the water, add a little muri- 

 atic acid, or spirit of salt. If a discharge of air 

 should ensue, the-marly nature ol" the earth will 

 be sufficiently established.' 



Then, to find their composition — 



' Pour a few ounces of diluted muriatic acid in- 

 to a Florence flask, place them in a scale, and let 

 them be balanced. Then red i]ce a few ounces of 

 dried marl into powder, and let this powder be 



* Dickson's Lancashire, Stevenson's edit., p. 491. 



