An essay on calcareous manures; by Edmund Ruffin

Front matter

NORTH CAROLINA STATE UNIVERSITY LIBRARIES

QniQQCono r>

14^\

Preface To The Edition Of 1832

The object of this Essay is to investigate the peculiar features and qualities of the soils of our tide-water district, to show the causes of their general unproductiveness, and to point out means, as yet but little used, for their effectual and profitable improvement. My observations are particularly addressed to the cultivators of that part of Virginia which lies between the sea coast and the falls of the rivers, and are generally intended to be applied only within those limits. By thus confining the application of the opinions which will be maintained, it is not intended to deny the propriety of their being farther extended. On the contrary, I do not doubt that they may correctly apply to all similar soils, under similar circumstances ; for the operations of Nature are directed by uniform laws, and like causes must everywhere produce like effects. But as I shall rely for proofs on such facts as are either sufficiently well known already, or may easily be tested by any inquirer, I do not choose to extend my ground bo far as to be opposed by the assertion of other facts, the truth of which can neither be established nor overthrown by any available or sufficient testimony.

The peculiar qualities of our soils have been little noticed, and the causes of those peculiarities have never been sought ; and though new and valuable truths may await the first explorers of this opening for agricultural research, yet they can scarcely avoid mistakes sufficiently numerous to moderate the triumph of success. I am not blind to the difficulties of the investigation, nor to my own unfitness to overcome them ; nor should I have hazarded the attempt, but for the belief that such an investigation is all-important for the improvement of our soil and agriculture, and that it was in vain to hope that it would be undertaken by those who were better qualified to do justice to the subject. I ask a deliberate hearing, and a strict scrutiny of my opinions, from those most interested in their troth. If a change, in most of our lands, from hopeless sterility to a high state of productiveness, is a vain fancy, it will be easy to discover and expose the fallacy of my views ; but if these views are well founded, none deserve better the attention of farmers, and nothing can more seriously affect tho future agricultural prosperity of our country. No where ought such improvements to be more highly valued, or more eagerly sought, than among us, where so many causes have concurred to reduce our products, and the prices of our lands, to the lowest state, and are yearly extending want, and its consequence, ignorance, among the cultivators and proprietors.

In pursuing this inquiry, it will be necessary to show the truth of various facts and opinions which as yet are unsupported by authority, and most of which have scarcely been noticed by agricultural writers, unless to be denied. The number of proofs that will be required, and the discursive course through which they must be reached, may probably render more

TREFACE TO THE EDITION OF 1832. vii

obscure the reasoning of an unpractised writer. Treatises on agriculture ought to be so written as to be clearly understood, though it should be at the expense of some other requisites of good writing ; and, in this respect, I shall be satisfied if I succeed in making my opinions intelligible to every reader, though many might well dispense with such particular explanations. Agricultural works are seldom considered as requiring very close attention; and therefore, to be made useful, they should be put in a shape suited to cursory and irregular reading. A truth may be clearly established — but if its important consequences cannot be regularly deduced for many pages afterwards, the premises will then probably have been forgotten, so that a very particular reference to them may be required. These considerations must serve as my apology for some repetitions — and for minute explanations and details, which some readers may deem unnecessary.

The theoretical opinions supported in this Essay, together witli my earliest experiments with calcareous manures, were published in the "American Farmer" (vol.'iii. page 318), in 1821. No reason has since induced me to retract any of the important positions then assumed. But the many imperfections in that publication, which grew out of my want of experience, made it my duty, at some future time, to correct its errors, and supply the deficiencies of proof, from the fruits of subsequent practice and observation. With these views, this Essay was commenced and finished in 1826. But the work had so grown on my hands, that instead of being of a size suitable for insertion in an agricultural journal, it would have tilled a volume. The unwillingness to assume so conspicuous a position as the publication in that form would have required, and the fear that my work would be more likely to meet with neglect or censure than applause, induced me to lay it aside; and to give up all intention of publication. Since that time, the use of fossil shells as manure has greatly increased, in my own neighbourhood and elsewhere, and has been attended generally with all the improvement and profit that was expected. But from paying no regard to the theory of the operation of this mauure, and from not taking warning from the errors and losses of myself as well as others, most persons have operated injudiciously, and have damaged more or less of their lands. So many disasters of this kind seemed likely to restrain the use of this valuable manure, and even to destroy its reputation, just as it was beginning rapidly to be extended. This additional consideration has at last induced me to risk the publication of this Essay. The experience of five more, years, 6ince it was written, has not contradicted any of the opinions then advanced— and no change has been made in the work, except iu form, and by continuing the reports of experiments to the present time.

It should be remembered that my attempt to convey instruction is confined to a single means of improving our lauds, and increasing our profits ; and though many other operations are, from necessity, incidentally noticed, my opinions or practices on such subjects are not referred to as furnishing rules for good husbandry. In using calcareous manure for the improvement of poor soils, my labours have been highly successful ; but that success is not necessarily accompanied by general good management and economy. To those who know me intimately, it would be unnecessary to confess the small pretensions that I have to the character of a good farmer ; but to others it may be required, for the purpose of explaining why other improvements and practices of good husbandry have not more aided, and kept pace with, the effects of my use of calcareous manures. E. R

1'rince George county, Virginia, January 20tk, 1832.

Tiii PREFACE TO THE EDITION OF 1835. '

EXTRACTS FROM THE PREFACE TO THE EDITION OF 1835.

Whb> the preceding ' edition of this Essay -was published, it-met with a'reception far more favourable, and a demand from purchasers much greater, than the author's anticipations had reached: and it is merely in accordance ■with the concurrent testimony of the many agriculturists who have since expressed and published opinions on the subject, to say that the publication baa already had great and valuable effects in directing attention, and inducing successful effbrte, t<< the improvement of land by calcareous mamires. Experimental knowledge on this head has probably been more than doubled within the last two years: and the narrow limits of the region within which marling had previously been confined, have been enlarged to perhaps ten-fold their former extent. Still, the circumstances now existing, however changed for the better, present a mere beginning of the immense and valuable improvements of soil, and increase of profits, that must hereafter grow out of the use of calcareous manures, if tluir operation is properly understood by those who apply them. But if used without that knowledge, their great value will certainly not be found: and indeed, they will often cause more loss than profit. It is therefore not so important to the farmers of our country at large to be convinced of the general and great value of calcareous manures — and to those in the great Atlantic tide-water bo know the newly established truth, that their beds of fossil shells furnish the best and cheapest of manures — as it is, that all should know in what manner, and by what general laws, these manures operate — how they produce benefit, and when they may be either worthless or injurious. And this more important end, the author regrets to believe has as yet scarcely been even partially attained, by the dissemination and proper understanding of correct views of the subject. Of course it is not to be supposed that this Essay has been read (if even heard of) by one in ten of the many who have been prompted by verbal information to attempt the practice it recommends : and of those who have real, and who have even expressed warm approbation of the work, it has seldom been found that their praise was discriminating, or founded upon a thorough examination of its reasoning and theoretical views, on which principally rests whatever value it may possess. For all persons who are so easily convinced, it may truly be said, that the volume embraced nothing more, and was worth no more, than would be stated in these few words — "the application of calcareous manures will be found highly improving and profitable." It is not therefore at all strange that the attentive reading of a volume, to obtain this truth, was generally deemed unnecessary.

Though the previous edition of this work has been nearly exhausted, the circulation has as yet been almost confined to that small portion of the state of Virginia alone in which the mode of improvement recommended had previously been successfully commenced, or had at least attracted much attention. But this district is not better fitted to be thus improved than the remainder of the great tide-water region stretching from Long Island to Mobile — and to a great part of which calcareous manures may be cheaply applied. It is only in parts of Maryland ana Virginia that many extensive and highly profitable applications of fossil shells, or marl, have been yet ■nade. In North Carolina the value of the manure has been but lately tried ; in South Carolina and Georgia, no notice of it has yet been taken, or at least has yet been made known: and in Florida and Alabama [parts of which are peculiarly suited to receive these benefits), it is most erron thought that such improvements are only profitable for long settled and impoverished countries. * * * * * *

Preface To The Edition Oe 1842. IX

P>ut {hough the circulation of this work will be most useful through the great tide-water region, which is so generally supplied with underlying beds of fossil shells, and so much of the soil of which especially needs such manure, still the assertion may be ventured that there is no part of the country where the views presented, if true, are not important to be known ; and, if known, would not be highly useful to aid the improvement of soils. It is to the general theory of the constitution of fertile and barren soils, that the attention and severe scrutiny of both scientific and practical agriculturists arc invited ; and to the several minor points them presented, which are either altogether new, or not established by authority— such as the doctrine of acidity in soils — of the incapacity of poor and acid soils to be enriched — and of the entire absence of carbonate of lime in most of the soils of this country.

EXTRACTS FROM THE PREFACE TO THE EDITION OF 1842.

In the few years which have passed since the issue of the preceding edition, it is believed that the use of marl and lime, in lower Virginia, has been extended over thrice as much land as had been previously thus improved ; and the previous clear income of the farmers thus fertilizing their lands has probably been already thereby increased in amount by several hundreds of thousands of dollars, and the intrinsic value of the lands raised by as many millions. These great augmentations of annual profits and of the true value of landed capital, from this single source, if* they could be accurately estimated, would be seen to have produced an important item of additional revenue to the treasury of the commonwealth. And these additions of wealth to individuals and to the state, would be obvious as well as real, but for the existence of other circumstances which have operated to counteract or to disguise the proper results. The most important of such influences will be merely referred to here iu the cursory manner only that the occasion permits.

In the first place — besides the deservedly very low appreciation of all lands in Virginia, founded on the smallness of their products, the market prices were formerly still more reduced by the almost universal urgent deeire of proprietors to sell, that they might be enabled then to emigrate to the new and rich lands of the west. The impossibility of selling, even at the lowest valuation price, was the only thing which prevented the actual flood of emigration being so much more swelled as to leave half our lands unoccupied and waste. If purchasers had but presented themselves, fully half the farms in Prince George county (and it is presumed of many other counties) might have been bought up at a considerable deduction from the lowest estimated value ; and all the sellers would have removed, with all their capital, to the western wilderness. To the then actual and regular flow of emigration from the now marling district, an effectual barrier has been opposed by the introduction of that mode of improvement. All emigration has ceased wherever by trial of this means the cultivators of the land found their labours to be richly repaid. Thus, in estimating the gains of individuals and of the state, on this score, the comparison should be made, not with the value of property and population which remained twenty years ago, but with what would have remained now, if the then existing inducements to emigration had continued to go on and to increase, as they would have done, with time.

Next — the actual increase of intrinsic value of marled lands is far from being even yet fully appreciated, because of the generally prevailing and

X PREFACE TO THE EDITION OF 1842.

very erroneous mode of estimating the values of the increase of permanent net income from land, (as will be made manifest in a part of this Essay — ) and but few even of those persons who have obtained such values by marling; their lands, would estimate them at one-fourth of their true amount. The source of any permanent net increase of only $6 of annual income from land, adds $100 to the intrinsic value of the land. And this proposition is not the less true, and to the full extent asserted, even though the estimate of private purchasers and sellers, and of public assessors of lands, may all count for the market price but a small proportion Of the increased real value.

Next — even whatever of new appreciation the foregoing influences might have permitted to be exhibited in the increased market price of lands, and Etill more their new real value, have been disguised, or altogether concealed, by the great and frequent fluctuations of all market prices of property, and by the general misdirections of capital and industry, all caused by the universal individual and national gambling (whether voluntary or compulsory), at the maddening and ruinous game of paper-money banking — to which system of delusion and fraud this otherwise most blessed country and fortunate people are indebted for so much of disaster, loss, and, still worse, of wide-spread corruption of habits and morals. The enormous apparent and illusory profits promised by this system, and by the stockjobbers who alone have fattened upon the facilities it offered for fraud and plunder, served powerfully to depress the market price of lands, and to discourage agricultural investments and pursuits. For, whatever actual profits the improvement and cultivation of the soil might offer to reward the care and labour of the proprietor, the stocks of various corporations, falsely appreciated by means of a bloated paper currency, and by the arts of stockjobbers, premised much higher profits, without requiring either care, labour, or risk. Thus, the higher that fictitious dividends of profits or the false values of stocks rose, and the stronger became the inducements to make stock investments, the more the prices of lands sank (comparatively) below their true value, because of the general disposition to convert landed capital to stock capital. But the real and solid increase of income and of wealth to individuals and to the commonwealth, caused by the permanent improvement of the soil, is not the less certain, or the less profitable, because fictitious appreciations of values, caused by the fraudulent banking system, and the consequent speculations and madness of its votaries and victims, have been both so much higher and lower, at different times, as to make the amount of actual improved values appear small in comparison, even if they were not thereby entirely concealed. But these delusive and ruinous causes of fluctuating prices and values are now fast showing their emptiness, and vanishing from view : and whenever the fraudulent paper system shall be completely exposed and entirely exploded, then both lands and the paper-money system will be estimated at their true value. May the consummation be speedy, complete, and final !

But even though, if properly and accurately estimated, the true valuo of the lands already marled and limed in Virginia has been increased to the amount of millions of dollars, the gain is very small compared to that which yet remains ready to be obtained. Marling has not yet been extended over the hundredth part of the surface to which it may be profitably applied ; and liming, not to the ten-thousandth part of the lands of the state to which lime may be brought. And elsewhere, with the exception of a small part of Maryland, the beginnings of marling only have as yet been made. Nevertheless, these beginnings are the widelyscattered seeds which will spring up and spread, and hereafter yield abundant harvests.

December, 1842.

Preface to earlier editions vi

Chapter I. — Introductory. General description of agricultural earths and soils. Physical and chemical constituents of soils.

Difficulties of defining earths and soils, 17, IS. Chemists' definitions unsuitable for agriculture, IS. Agricultural earths, 19. Siliceous earth, 19. Aluminous, 20. Calcareous, 20; different definitions thereof by authors, 22. Chalk, 23. Magnesiau earth, 24. Humus, 25. toils aud sub-soils, 25. Constituents of soils, 26, and of sub-soils, 27. Physical and chemical constituents, 28, 29, 30. Nomenclature and definitions of soils, 31, 32, 33.

Chap. II. — On the soils and state of agricidture of the Tide-ivater District of Virginia

General features of the district and its soils, 34, 36. Ridges, 35. Slopes, 35, 36. River margins and alluvial lands, 36. Exhausting tillage and small products, 36. Decreasing population, 3S. Hopeless of improvement under existing circumstances, 39.

Chap. III. — The dijferent capacities of soils for improvement

Five principal propositions stated for discussion, 39. Natural fertility defined, 40. Permanency of either fertile or sterile character of different countries and soils, 41. Land naturally poor not capable of being enriched by putrescent manures, 41, 42. Opposing opinions and authorities, 43, 45. Facts in support, 44. The degree of original fertility tho limit of profitable improvement by putrescent manures, 46, 47.

Chap. IV. — Effects of the presence of calcareous earth

Calcareous earth not found in our poor soils, 48. Its presence indicating great fertility, 48. Natural growths on shelly and on poor soils, 49. All authority supports the general presence of carbonate of lime in soils, 50 to 53. Soils rarely calcareous in Virginia, 54. Recent confirming testimony (note),' 54, 55.

Chap. V. — Results of chemical examinations of various soils

Methods for testing the presence or absence of carbonate of lime in soils, 58 to 59. Various soils tested — calcareous, 59 to 61. All known calcareous soils rich, and no poor soil calcareous, 61.

Chap. VI. — Chemical examination of rich soils containing no calcareous

earth.

Rich river lands, C2 — and also mountain lime-stone soils, 63 to 65. Trairie soils of Alabama generally highly calcareous, or super-calcareous, 66, 67.

Chap. VII. — Proofs oftlie existence of acid and neutral soils

lime in some form present in every soil, 68. Acid not considered an ingredient of soil by any writers of authority, and denied by others, 69, 70. Proofs of acidity in soil, 70. Growth of acid plants. 71. Nourished best by dead acid plants, 71, 72. By other putrescent manures, 72. Acid poisonous to cultivated plants. 73. Disappearance of carbonate of lime in cultivated soils, 75 to SO. Wood ashes contain lime, 81, 82. Scientific confirmation of add in soil, 82 to 88. Discovery of humic acid, 83 ; its properties, 86. Successive natural changes of chemical character in soils, S8, 89, 90. Testimony of Loudon of originality of doctrine (note), 91.

Chap. VIII. — The mode of operation by which calcareous earth increases tJie fertility and productiveness of soils.

SBicioua and aluminous earths have no chemical power to retain putrescent manure, 92, 93, 94. Calcareous earth, has such power, and how, 94, 95. Examples of combining operations, 95. Power of fixing fertilizing matters in soils. 96. Power of neutralizing injurious acids, 97, 93. Power of altering and improving texture of both sandy and clayey soils, 98,

TO

Xii CONTENTS.

99, and of lc-.soning evils of too much dryness and moisture, 99. Lime a necessary food for plants, but only within narrow iiniita'tion, 100, lol. Proportions of lime in ashes of various plants, 102. __

Chap. IX. — Action of caustic time as manure

Davy's theory of liming stated, lU.X Applied to practice, 104. Action of caustic lime generally to 1 e avoided, 104. Lime acts generally as carbonate, 105. form of classification of manures, 10(3.

Chap. X. — Introductory and general observations on marl and lime

Fossil shells, improperly called marl, 107. Incorrect use of terms in England. 10S-9. Different and general misapplications of the name of ••marl" (note), 109, and of "marling" (note), 110. "Liming," in practice, equivalent to marling. 110 to 113. Preliminary remarks on experiments, 114. Oldest applications of marl in Virginia, 114.

Chap. XI. — Experiments with, and effects of, calcareous manures on acid sandy soils, newly cleared.

Experiments stated, and earliest and later results on light and acid loam, recently brought \iuder cultivation, 116 to 122. Errors in the mod.e of experimenting stated, 122-4.

Chap. XII. — Effects of calcareous manures on acid clay (or stiff) soils recently cleared

Description of the peculiar soil operated on, 124. Experiments and results stated, 125 to 129. Pomarkable effects on clover and grain crops, 127 to 129.

Chap. XIII. — The effects of calcareous manures on acid soils reduced by

cidtivalion.

Marling always effective on such soils, 130. Experiments stated, and early good results. 130 to 136. Diseased crops of grain caused by excessive mailing, 133. Effects of marl with putrescent manure, 137, 138.

Chap. XIV. — Effects of calcareous manures on "free light land."

Character of such soil, 139. Experiments, 139, 140.

Chap. XV. — Effects of calcareous manures on exhausted acid soils, under their second growth of trees.

Experiments of this kind, 141, 142.

Chap. XVI. — Effects of calcareous manures alone, or witli gypsum, on calcareous and neutral soils.

Inefficiency of marl on such soils, 143. Gypseous marl, 144. Experiments, 145 to 147.

Chap. XVII. — Digression to the theory of the action of gypsum as manure. Supposed cause of its want of power and value on acid soils.

General inefficiency of gypsum on Atlantic coast, and mistaken views as to the cause, 147. Exceptions on neutral soils, 148. And the true cause of usual inefficiency, 149. Theory of this inefficiency, and its removal, 151 to 154.

Chap. XVIII. — The damage caused by too heavy dressings of calcareous manure, and. the remedy.

Earliest effects observed, and symptoms described, 155. Means for preventing or of curing the injur}', 156-7. The disease found ouly on soils naturally acid. I"i7: and not caused merely by excess of calcareous earth, 15S, and probably by huraate of lime. 159.

Chap. XIX. — Recapitulation and more full statements of the effects of calcareous manures.

The results of marling have conformed to previous theoretical views, 159. Exceptions above the granite range, and causes, 161. Hazel loam, 161. Effects of calcareous manure proportioned to the organic matter in soil, 162. Marl on " galls," 163. Prevents the washing effects by rain-, ami the moving of sandy soils by winds, 104. Quantities of marl to be applied, 166. Effects in preserving vegetable matter from waste, 167. -'Free light land," and its speedy exhaustion* 168. Marling deepens soils, 109. Gives peculiar value to sandy sub-soils, 170. Hastens maturing of orops — cotton — wheat, 170. Strengthens straw of wheat, 171. Peculiar benefits to leguminous plants, and especially to clover, 172. and to some bad weeds, 17 S. Failures of clover on marled lands, 173. Effect of cabling in eradicating acid plants, 174-5.

CONTENTS. X1H

Chap. XX.— Directions for the use of marl in connexion with other farm ing operations.

Usual difficulties of beginners without reason. 170. The labours to *J&*£^<%jg£.

ous 170. Necessity for intermixing marl regularly With the soil, 176-7. Mam ci ot drop ,, -ml sproadin- heaps, 177. Organic manure an essentia! aCMmpanlment, 177, 178, S%Sd I by ^getahle growth of ttottdf, 178. Orainary farm-made manures, 1.9; other materials, 180.

Chap. XXI.— Actual improvements and restdts of marling. Pecidiar value of sandy soils.

Causes of defective results of earliest marling labours, 181-2. Actual results on CoggtaS

i'uint f ,rm t, 184J, 1S3. Crops from 1813 to 1851,181. Remarks and notes on same,

*'" CuUire and crops on Marlbourne, 187-8. Causes of neglect of marling and small

effects, is"! Value of sandy soils, 190. Poor soils of lower Virgin* alflO very shallow, 191.

Rates of Increase of products from marling, on different lands, 192.

Ch\p. XXII.— The extent of duration of the effects of calcareous manures.

Duration of effects known by experience, 192-4. ?»^^^^^^L^^ of duration of calxing, 190. Practice and opinions in Britain, 10-, 198. Alleged reasons for waste of lime in so Is, and answers thereto, 199 to 211. Sinking of lime in so. 211,

?-l- 1 le t f organic .or putrescent) manures made permanent by combinat.on w. h cal- ;,-Wu= 214 to210. Apparent exceptions, 217. Actual duration of effects, 21S Antic- ,"ted progress of improvement, and tixing of organic matter by calxing, 219-and of sterility caused, under reverse circumstances, 220.

Chap. XXIIL— General observations on the valuations of lands and their " improvements, and the expenses and profits of marling.

Tibial estimates aUo<*ether erroneous, 221. True mode of estimating values, 222 to 225. Supply Zl demand regulate selling prices of lands, 227. Injudicious marling labours, 228. General profits, 229.

Chap. XXIV.— Other fertilizing potcers and effects of calcareous earth.

Soils of ancient alluvial formation (or latter drift), 230. Effects of calxing thereon, 231 to 933 Action of calx bv solvent power, 231. Sterility, when caused by ca x.ng. and low, 235' to 237 T Benefit of lenient cropping, 237, and supplying .vegetable inn tor, «. Erroneous practice in South Carolina, 239 to 241. Organic matter « #8*^ 242 ;] ^WCOB*l. tuted 243. Proportions of carbon, hydrogen, oxygen, and azote in plants, 244. Whence derived, 240 to 248. Supply of carbon from the atmosphere increased on calcareous so 1 218 to 250. Dr. Wight's experiments thereupon, 250 to 25 L Otter proofe^ *^££ supplied from the atmosphere through leguminous plants, 253 to 257. then peculiar ma n rin' efforts thus caused, 258. Residue of roots of clover, Ac... 259. Value of the southern firtd pea (or bean), 201. Recapitulation, 202. Effect of lime in soils and compost lTeaps to produce nitrates. 203. This explains some practical results before not understood •'on' 207 Effect of lime in promoting the healthy constitution and vigorous growth of plants, 207, 208, and the better quality of products, 208.

Chap. XXV. The use of calcareous earth recommended to preserve

' putrescent manures, and to promote cleanliness and health.

Effects of calcareous earth in preventing waste of products of animal matter 209, 278. Cases for use of this power 271 to 274. Unfitness of quick-lime for this purpose, 274. Benefit in PlUenti f d srease 275 270. How the burning of towns benefit, health 277. Benefits to health of calcareous soil in Alabama, 278-in Virginia, 279 to 281-m 1 ranee, 281, 2S3- in England, 283.

Chap. XXVI.— The excavation of marl-pits, and carrying out and applying marl.

,,.,,. , oqi Wot marl in hillv lands, 285. Method of opening and work-

"KrttaSSS? Z r ' SStem Draining the excavation, 289, 290. Deep pitting 290. mg pits ot sum man, _ >■/ Makimx roads. 295. Implements and carts for

££?»! ftSSfiS^wS tables^estiniates, 299Pto 302. Importance of marling labours being continuous, 303.

Cn vp XXVII —Directions for the searching for and testing of marl.

S^tnL^TSJL S ^SSSS 310 to 313! Distant transportation of marl, 313

O

XIV CONTENTS.

Cn.vr. XXVIII. — Est!, nates ofilie cost of labour applied to marling.

The pi -. 3T*. Cost of the lal-our of a negro man? 319 — r.f l*rr,

. rse and mu' . f carta ar.<l implements,

321. - as of margin.-. --

Chat. XXIX. — Details of actual and extensive marling labours.

A . low-lying and wet marl, 327. Marl and accompanying leds described,

n in sniaD perpendicular pits. 329. Horizontal plan 330-31.

Beginning and pro; . - mole, --A .

ma: ■ w.irk. and remarks, 336 to 341. marl in large graduated

■ 350. ^aTii:_- - • various dis-

tances, and rule : . I of large excavations,. 354. Quantity of marl

remove

Chap. XXX. — The progress of marling in Virginia. Usual obstacles to the progress of all new improvers en inning

an i ; . in Virginia, and general c 2). •. liming,