40 



FARMERS' REGISTER, 



[No. 1. 



careons marl proper,) and therefore is manifestly 

 not necessary to be sought for in such marl. 

 Then as to the main and all-important ingredient 

 of marl, the calcareous earth, or carbonate of lime, 

 an unnecessary obscurity is thrown over it by 

 stating its amount in its two component parts of 

 lime and carbonic acid, in separate columns. 

 There is no reason for this, as these constituents 

 always combine in certain and invariable propor- 

 tions, to form carbonate of lime. But this is not 

 known to every reader, and therefore the arrange- 

 ment adopted keeps many entirely in the dark as 

 to the strength of marl, and is even somewhat em- 

 barrassing and troublesome to the inspection of 

 those who well know the proportions in which the 

 constituents of carbonate of lime combine. If, for 

 example, the marl marked 6 in the table, (p. 61,) 

 had been staled to contain 38 parts of carbo- 

 nate of lime, or shelly matter, in the 100, it would 

 have been plain to every one: but as it is there 

 stated to contain 21.25 of lime, and 16.15 of car- 

 bonic acid, it may be well doubted whether the in- 

 formation contained is not hidden from most of those 

 interested in the report, and lor whose benefit it 

 was specially designed. Indeed, the constituent 

 parts are improperly stated chemically, as well as 

 ior common and practical purposes. Neither 

 "lime," nor "carbonic acid," ever exists in marl — 

 but a third substance formed of these two. If it 

 were proper to name the separate constituent 

 parts of a body, though never found except in com- 

 bination, instead of the compound itself— then the 

 author ought to have gone back a step farther, 

 and stated these ingredients in the more remote 

 elements, which constitute by their combination 

 the lime and carbonic acid — dividing the first into 

 calcium and oxygen, and the latter into carbon and 

 oxygen. Yet we have known nearly a dozen dif- 

 ferent men and boys, who, without knowing the 

 meaning of either of these terms, or even in what 

 proportions carbonic acid and lime combined to 

 form the carbonate of lime, could analyze marl 

 with so much ease and correctness, that their re- 

 sults might be received with confidence. To sep- 

 arate correclly and ascertain the proportion of the 

 calcareous ingredients of marl, may be learned 

 and practised more easily than either of the house- 

 hold jobs of making a pot of soap, or a loaf of 

 good bread — both of which are also chemical 

 operations. The process is so mechanical, that it 

 has occurred to our mind that the business of 

 marl proving was one that might be carried on ad- 

 vantageously for the undertaker, and still more so 

 for his employers or customers. Any intelligent 

 youth, or female, might learn the processes in a 

 fnw days, and then, if receiving sufficient employ- 

 ment, might analyze any specimens of marl fur- 

 nished, for a very small compensation, and yet 

 make good profits. The indolence or negligence 

 of most marling farmers will always prevent their 

 performing this necessary operation for themselves 

 — and perhaps many who even understand the 

 process, would prefer to pay 50 or 100 cents for 

 each trial, to any competent person who would 

 undertake the trouble. 



But besides the making a mysterious and diffi- 

 cult business of a very simple and easily practica- 

 ble operation, there are strong objections to the re- 

 sults of the author, even though obtained by so 

 much superfluous skill and care. In the general 

 remarks on the table, he says — 



"The owners of the marl-beds from which these 

 specimens were taken, are informed that the opera- 

 tions tor analysis have been conducted on small quan- 

 tities of the marl (generally the friable portions of it) 

 the larger fragments of fossil shells having been cast 

 aside; so that when applied in considerable quantities, 

 these shells will by their disintegration, furnish an ad- 

 ditional proportion of carbonate of lime and conse- 

 quently enhance the value of the marl. It was deemed 

 more advantageous to operate in the manner just indi- 

 cated, in order to ascertain more accurately the respec- 

 tive proportions of the diiferent ingredients." 



It is very true that this disintegration will go 

 on, and consequently enhance the value of the 

 marl; and the practical marler knows that this 

 process generally proceeds so rapidly, that to ex- 

 clude all the larger fragments of shells from the 

 analysis, is equivalent to destroying its pretensions 

 to accuracy. There are certainly objections to in- 

 cluding the most indestructible shells, without any 

 separate notice, and counting all the parts asalike: 

 but of the two, this mode w r ould be more correct, 

 agriculturally as well as chemically, than the one 

 adopted. The farmer knows, or will soon learn, that 

 the fossil oyster, and scallop shells are very slow 

 in coming to pieces, and that therefore they are of 

 but little value. But the white shells seem to be 

 dissolved by combining with the soil, (if in a soil 

 much needing calcareous manure,) and however 

 solid when applied, will mostly disappear in a lew 

 years. 



So much as to the analysis itself. But even if 

 that process is perfectly accurate, and altogether 

 unobjectionable as to each particular specimen of 

 marl, the manner of selecting the specimens may 

 have been such that the results of analysis may 

 be of little value for showing the average strenglh 

 of even one body of marl — and of far less, as evi- 

 dences of the average quality of the marls of a 

 neighborhood generally. The geologist does not 

 always say how his specimens were oblained: but 

 as it is almost impossible that he could have se- 

 lected many himself, it may be inferred that most 

 of the specimens were selected by other persons. 

 Then the chemist is not responsible for the speci- 

 mens showing anything like fair averages of qua- 

 lity, and there are several reasons for believing 

 that without a proper and careful selection of spe- 

 cimens, the most correct analysis is of no vdue, 

 except as showing the constitution of the particu- 

 lar specimen examined — or (in some rare cases,) 

 some new ingredient, (as green sand, for exam- 

 ple,) and of course suggesting the probability of 

 the presence of that ingredient through an exten- 

 sive region. When the author describes the 

 marls of a particular farm, and even generally of 

 a neighborhood, he refers, in most cases, (as is 

 seen in the foregoing extracts,) to one or two spe- 

 cimens only, in his table, to show the quality. Now 

 we have rarely, if ever, seen a single bed of marl 

 dug into eight feet, that did not present different 

 layers of various degrees of strength in shelly 

 matter. Sometimes one layer lying within a foot 

 of another, above or below, is of double the 

 strength — and sometimes a bed which in part con- 

 tains 60 or 70 per cent, of carbonate of lime, will 

 in another part be below 20, and not worth using. 

 The diversity is greater, in different beds on the 

 same farm, and still greater through a neighbor- 

 hood of some extent. Of course, one or two spe- 

 cimens, and especially without particularly de- 



