dy eee tee se 4 oprah N Ss N N ic on ee Re Pos ee c a ro } % ee “ a “oe & re we a 6 SN ea I He NN ELEMENTS OF. Agricultural Chemistry, - IN A COURSE OF LECTURES : viet THE BOARD OF AGRICULTURE. BY Sir Humphry Davy, Ub. D. FOR. 2 LOS Re Va PSR. MEMBER OF THE BOARD OF AGRICULTURE, OF THE ROYAL IRISH ACADEMY, OF THE ACADEMIES OF ST. PETERSBURGH, STOCKHOLM, BERLIN, PHILADELPHIA, &e., AND HONORARY PROFESSOR OF CHEMISTRY TO THE ROYAL INSTITUTION, TO WHICH IS ADDED, A TREATISE ON SOILS AND MANURES, AS t FOUNDED ON ACTUAL EXPERIENCE, AS COMBINED WITH THE LEADING PRINCIPLES OF AGRICULTURE: IN WHICH THE ‘GHEORY AND DOCTRINES OF SIR HUMPHRY DAVY, AND OTHER AGRICULTURAL CHEMISTS, ARE RENDERED FAMILIAR TO THE EXPERIENCED FARMER, BY A PRACTICAL AGRICULTURIST. ee ee ee PHILADELPHIA: PUBLISHED BY E. WARNER, M. Caney & SON, AND BENNETT & WALTON: AND IN BALTIMORE, BY F. LUCAS JR., JOSEPH CUSHING, AND EDWARD J. COALE, ‘4824 “ar os TO THE PRESIDENT AND MEMBERS THE BOARD OF AGRICULTURE FOR THE YEAR 1812, THBSE LACTURBS, PUBLISHED AT THEIR REQUEST, ARE INSCRIBED AS A TESTIMONY OF THE RESPECT OF THE AUTHOR, AND OF HIS GRATITUDE FOR THE ATTENTION WITH WHICH THEY HAVE BEEN RECEIVED. ADVIARTTSE MON Hs ~ DURING ten years, since 1802, I have had the honour; every Session, of delivering Courses of Lectures before the Board of Agriculture. I have endeavoured, at all times, to follow in them the progress of chemical discovery ; they have therefore varied every year: and such is the rapidity with which Chemistry is extending, that some alterations and im- provements were rendered necessary at the time they were preparing for the press. — The Duke of Bedford has enabled me to stamp a value upon this Work, by permitting me to add to it the results of the experiments instituted by His Grace upon the quantity of produce afforded by the different grasses. I am indebted for much useful information to many mem- bers of the Board; of which acknowledgements will be found in the body of the Work. If there are any omis- ; sions on this head, I trust they will be attributed to defect of recollection, and not to any want of candour or of gra- titude. Where I have derived any specific statements from books, I have always quoted the authors; but I have not always made references to such doctrines as are become current, the authors of which are well known ; and which may be almost considered as the property of all enlightened minds. Amongst books to which [ have not referred for any par- ticular facts, but which contain much useful general informa- tion, I shall mention the Earl of Dundonald’s ‘Treatise on 4 hy Vi ADVERTISEMENT. the Connection of Chemistry wich Agriculture ; Dr. Rennie’s Dissertations on Peat; and the General Report of the Agri- culture of Scotland, This last work did not come into my hands till the concluding sheets of these Lectures were print-' ing {iad it been in circulation before, I should have profit- ed by many statements given in it, particularly those of the opinions of the enlightened Professor of Agriculture in the University of Edinburgh: and I should have dwelt with satisfaction on the importance given to some chemical doc- trines by his experience. | Berkeley Square, March 21, 1813. CONTENTS. LECTURE I. Paces INTRODUCTION. General* Views of the Objects of the Course, and of the Order in which they are to be discussed, 9 LECTURE I. Of the general Powers of Matter which influence Vegetation ; of Gravitation, of Cohesion, of Chemical Attraction, of Heat, of Light, of Electricity, ponderable Substances, Elements of Matter, particularly those found in Vegetables, Laws of their Combinations and Arrangements, - - - - - 27 LECTURE IIL. Gn the Organization of Plants. Of the Roots, Trunk, and Branches ; of their Structure. Of the Epidermis. Of the cortical and alburnous Parts of Leaves, Flowers and Seeds. Of the chemical Constitution of the Organs of Plants, and the Substances found in them. Of mucilaginous, saccharine, extractive, resinous, and oily Substances, and other vegetable Compounds, their Arrangements in the Organs of Plants, their Composition, Changes, and Uses, - - ve - 43. LECTURE IV. On Soils; their constituent Parts. On the Analysis of Soils. Of the Uses of the Soil. Of the Rocks and Strata found beneath Soils. Of the Improvement of Soils, - - 109 LECTURE VY. On the Nature and Constitution of the Atmosphere, and its In- fluence on Vegetables. Of the Germination of Seeds. Of the Functions of Plants in their different Stages of Growth; with a general View of the Progress of Vegetation, - 143 Vill. > CONTENTS. LECTURE VI. — ah ; \, Pace, - Of Manures of vegetable and animal Origin. Of the Mange sy in which they become the Nourishment of the Plant. Of — Fermentation and Putrefaction. Of the different Species of Manures of Vegetable origin; of the different Species of animal Origin, Of mixed Manures. General Principles with respect to the Use and Application of such Manures 184 LECTURE VII. Of Manures of Mineral Origin, or fossile Manures : their Pre- paration, and the Manner in which they act. Of Lime in its different States; Operation of Lime as a Manure and a Ce- ment; different Combinations of Lime. ' Of Gypsum ; Ideas respecting its Use. Of other Neutro-saline Compounds, employed as Manures. Of Alkalies and alkaline Salts; of common Salt, - - - - - - - =~ re F3 LECTURE VII. On the Improvement of Lands by burning; chemical Princi- ples of this Operation. On Irrigation and its Effects. On Fallowing ; its Disadvantages and Uses. On the convertible ~ Husbandry founded on regular Rotations of different Crops. On Pasture. On various Agricultural Objects connected with Chemistry. Conclusion, - - - - + \ APPENDIX. An Account of the Results of Experiments on the Produce and Nutritive Qualities of different Grasses, and other Plants, nsed as the Food of Animals. - : - o (fella: MRIS to ive) iv] A GOURSE OF WACTURDS, se. LECTURE I. Introduction. General Views of the Objects of the Course, and of the Order in which they are to be dis- cussed. Lv is with great pleasure that I receive the permission to address so distinguished and enlightened an Au- dience on the subject of Agricultural Chemistry. That any thing which [ am able to bring forward, should be thought worthy the attention of the Board of Agriculture, I consider as an honour; and I shall en-> deavour to prove my gratitude, by employing every ex- ertion to illustrate this department of knewledge, and to point out its uses. ’ In attempting these objects, the peculiar state of the inquiry presents many difficulties to a Lecturer. Agri- cultural Chemistry has not yet received a regular and systematic form. It has been pursued by competent experimenters for a short time only ; the doctrines have not as yet been collected into any elementary treatise; - and on an occasion when [ am obliged to trust so much to my own arrangements, and to my own limited in- formation, I cannot but feel diffident as to the interest that may be excited, and doubtful of the success of the © undertaking. 1 know, however, that your candour will induce you not to expect any thing like a finished work upon a science as yet in its infancy; and L am sure you will receive with indulgence the first attempt made to illustrate it, in a distinct course of public lectures. Agricultural Chemistry has for its objects all those changes in the arrangements of matter connected with the growth and nourishment of plants; the compara- B 10 tive values of their produce as food; the constitution of soils; the manner in which lands are enriched by manure, or rendered fertile by the different processes of cultivation. Inquiries of such a nature cannot but be interesting and important, both to the theoretical agri- culturist, and to the practical farmer. ‘'I'o the first, they are necessary in supplying most of the fundamen- tal principles on which the theory of the art depends. To the second, they are useful in affording simple and easy experiments for directing his labours, and for en- abling him to pursue a certain and systematic plan of improvement. It is scarcely possible to enter upon any investiga- tion in agriculture without finding it connected, more or less, with doctrines or eludications derived from che- mistry. If land be unprodué¢tive, and a system of ameliora- ting it is to be attempted, the sure method of obtaining the object is by determining the cause of its sterility, which must necessarily depend upon some defect in the constitution of the soil, which may be easily discovered by chemical analysis. } Some lands of good apparent texture are yet sterile in a high degree; and common observation and com- mon practice afford no means of ascertaining the cause, or of removing the effect. The application of chemi- cal tests in such cases is obvious; for the soil must contain some noxious principle which may be easily discovered, and probably easily destroyed. Are any of the salts of iron present? they may be decomposed by lime. Is there an excess of siliceous sand? the system of improvement must depend on the application of clay and calcareous matter. Is there a defect of calcareous matter? the remedy is obvious. Is an excess of vegetable matter indicated? it may be removed by liming, paring, and burning. Is there a deficiency of vegetable matter? it is to be supplied by manure. A question concerning the different kinds of lime- stone to be employed in cultivation often occurs. To determine this fully in the common way of experience, would demand a considerable time, perhaps some years, 11 and trials which might be injurious to crops; but by simple chemical tests the nature of a limestone is dis- covered in a few minutes; and the fitness of its appli- cation, Whether as a manure for different soils, or as a cement, determined. Peat earth of a certain consistence and composition is an excellent manure; but there are some varieties of - peats which contain so large a quantity of ferruginous matter as to be absolutely poisonous to plants. No- thing can be more simple than the chemical operation for determining the nature, and the probable uses of a substance of this kind. There has been no question on hi more difference of opinion has existed, than that of the state in which manure ought to be ploughed into the land; whether recent, or when it has gone through the process of fer- mentation? and this question is still a subject of dis- cussion; but whoever will refer to the simplest princi- ples of chemistry, cannot entertain a doubt on the sub- ject. As soon as dung begins to decompose, it throws off its volatile parts, which are the most valuable and most efficient. Dung which has fermented, so as to be- come a mere soft cohesive mass, has generally lost from one third to one half of its most useful constituent ele- ments. It evidently should be applied as soon as fer- mentation begins, that it may exert its full action upon the plant, and lose none of its nutritive powers. It would be easy to adduce a multitude of other in- stances of the same kind; but sufficient L trust has been said to prove, that ¢he connexion of Chemistry with Agriculture is not founded on mere vague speculation, but that it offers principles which ought to be under- stood and followed, and which in their progression and ultimate results, can hardly fail to be highly beneficial to the community. A view of the objects in this Course of Lectures, and of the manner in which they are to be treated, will not, I hope, be considered as an improper introduction. It will inform you what you are to expect; it will afford a general idea of the connexion of the different parts of the subject, and of their relative importance; it will _ enable me to give some historical details of the progress 12 of this branch of knowledge, and to reason from what has been ascertained, concerning what remains to be in- vestigated and discovered. The phenomena of vegetation must be iandbccd as an important branch of the science of organized nature 5 but though exalted above inorganic maiter, vegetables are yet in a great measure dependent for their exist- ence upon its laws. ‘They receive their nourishment from the external elements ; they assimilate it by means of peculiar organs: and it is by examining their physi- cal and chemical constitution, and the substances and powers which act upon them, and the modifications which they undergo, that the scientific principles of Agricultural Chemistry are obtained. According to these ideas, it is evident that the study ought to be commenced by some general inquiries into the composition and nature of Heil bodies, and the laws of their changes. ‘The surface of the earth, the atmosphere, and the water deposited from it, must either together or separately afford all the pr inciples concerned in vegetation ; and it is only by examining the chemical nature of these principles, that we are capable of dis- covering what is the food of plants, and the manner in which this food is supplied and prepared for their nou- rishment. ‘The principles of the constitution of bodies, consequently, will form the first subject for our consi- deration. By methods of analysis dependent upon chemical and electrical instruments discovered in late times, it has been ascertained that all the varieties of material sub- stances may be resolved into a comparatively small number of bodies, which, as they are not capable of being decompounded, are considered in the present state of chemical knowledge as elements. The bodies im- capable of decomposition at present known are forty- seven. Of these, thirty-eight are metals; six are in- flammable bodies; and three substances which unite with metal and inflammable bodies, and form with them acids, alkalies, earths, or other analogous com- pounds. ‘The chemical elements acted upon by attrac- tive powers combine in different aggregates. In their simpler combinations, they produce various crystalline 13 substances, distinguished by the regularity of theirforms. In more complicated arrangements they constitute the varieties of vegetable and animal substances, bear the higher character of organization, and are rendered sub- -servient to the purposes of life. And by the influence of heat, light, and electrical powers, there is a constant series of changes; matter assumes new forms, the de- struction of one order of beings tends to the conserva- tion of another, solution and consolidation, decay and renovation, are connected, and whilst the parts of the system continue in a state of fluctuation and change, the order and. harmony of the whole remain unalterable. After a general view has been taken of the nature of the elements, and of the principles of chemical changes, the next object will be the structure and constitution of plants. In all plants there exists a system of tubes or vessels, which in one extremity terminate in roots, and at the other in leaves. It is by the capillary action of the roots that fluid matter is taken up from the soil. The sap in passing upwards becomes denser, and more fitted to deposit solid matter : it is modified by exposure to heat, light, and air in the leaves; descends through the bark, in its progress produces new organized mat- ter; and is thus in its vernal and autumnal flow, the cause of the formation of new parts, and of the more perfect evolution of parts already formed. In this part of the inquiry [ shall endeavour to con- nect tegether into a general view, the observation of the most enlightened philosopkers who have studied the physiology of vegetation. ‘Those of Grew, Malpighi, Sennebier, Darwin, and, above all, of Mr. Knight. He is the latest i inquirer into these interesting subjects, and his labours have tended most to illustrate this part of the economy of nature. The chemical composition of plants has within the last ten years, been elucidated by the experiments of a number of chemical philosophers, both in this, and in other countries; and it forms a beautiful part of gene- ral chemistry; it is too extensive to be treated of mi- nutely ; but it will be necessary to dwell upon such parts of it, as afford practical inferences. Tf the organs of plants be submitted to chemical ana- 14 lysis, it is found that their almost infinite diversity of form, depends upon different arrangements and combi- nations of a very few of the elements; seldom more than seven or eight belong to them, and three constitute the greatest part of their organized matter ; and accord- ing to the manner in which these elements are disposed, arise the different properties of the products of vegeta- tion, whether employed as food, or for other purposes and wants of life. The value and uses of every species of agricultural produce, are most correctly estimated and applied, when practical knowledge is assisted by principles derived from chemistry. ‘The compounds in vega- tables really nutritive as the food of animals, are very few; farina or the pure matter of starch, gluten, sugar, vegetable jelly, oil, and extract. Of these the most nutritive is gluten, which approaches nearest in its na- ture to animal matter, and which is the substance that gives to wheat its superiority over other grain. The next in order as to nourishing power is oil, then sugar, then farina; and last of all gelatinous and extractive matters. Simple tests of the relative nourishing pow- ers of the different species of food, are the relative quantities of these substances that they afford by ana- lysis; and though taste and appearance must influence the consumption of all articles in years of plenty, yet they are less attended to in times of scarcity, and on such occasions this kind of knowledge may be of the greatest importance. Sugar and farina or starch, are very similar in composition, and are capable uf being > converted into each other by simple chemical processes. In the discussion of their relations, I shall detail to you the results of some recent experiments, which will be found possessed of applications both to the economy of vegetation, and to some important processes of manu- facture. . All the varieties of substances found in plants, are produced from the sap, and the sap of plants is de- rived from water, or from the fluids in the soil, and it is altered by, or combined with principles derived from the atmosphere. The influence of the soil, of water, and of air, will therefore be the next subject of consid- 15 eration. Soils in all cases consist of a mixture of dif- ferent finely divided earthy matters; with animal or vegetable substances in a state of decomposition, and certain saline ingredients. ‘The earthy matters are the true basis of the soil; the other parts, whether na- tural, or artificially introduced, operate in the same manner as manures. Four earths generally abound in soils, the aluminous, the siliceous, the calcareous, and the magnesian. These earths, as I have discovered, consist of highly inflammable metals united to pure air or oxygene; and they are not, as far as we know, de- composed or altered in vegetation. The great use of the soil is to afford support to the plant, to enable, it to fix its roots, and to derive nourish- ment by its tubes slowly and gradually, from the solu- ble and dissolved substance mixed with the earths. That a particular mixture of the earths is connected with fertility, cannot be doubted: and almost all ste- rile soils are capable of being improved, by a modifica- tion of their earthy constituent parts. I shall describe the simplest method as yet discovered of analysing soils, and of ascertaining the constitution and chemical ingre- dients which appear to be connected with fertility ; and on this subject many of the former difficulties of inves- tigation will be found to be removed by recent inquiries. The necessity of water to vegetation, and the luxu- riancy of the growth of plants connected with the pre- sence of moisture in the southern countries of the old continent, led to the opinion so prevalent in the early schools of philosophy, that water was the great produc- tive element, the substance from which all things were capable of being composed, and into which they were finally resolved. "The & agicrev wev idue” of the poet, «< water is the noblest,”’ seems to have been an expres- sion of this opinion, adopted by the Greeks from the Egyptians, taught by Thales, and revived by the al- chemists in late times. Van Helmont in 1610, con- ceived that he had proved by a decisive experiment, that all the products of vegetables were capable of be- _ ing generated from water. His results were shewn to be fallacious by Woodward in 1691; but the true use 16 of water in vegetation was unknown till 1785; when Mr. Cavendish made the grand discovery, that it was composed of two elastic fluids or gases, inflammable gas or hydrogene, and vital gas or oxygene. ie Air, like water, was regarded as a pure element by most of the ancient philosophers: a few of the chemi- cal inquirers in the sixteenth and seventeenth centuries, formed some happy conjectures respecting its real na- ture. Sir Kenelm Digby in 1660, supposed that it con- tained some saline matter, which was an essential food of plants. Boyle, Hooke, and Mayow, between 1665 and 1680, stated, that a small part of it only was con- sumed in the respiration of animals, and in the combus- tion of inflammable bodies ; but the true statistical ana- . lysis of the atmosphere is comparatively a recent la- bour, acheived towards the end of the last century by Scheele, Priestley, and Lavoisier. ‘These celebrated men shewed that its principal elements are two gases, oxygene and azote, of which the first is essential to flame, and to the life of animals, and that it likewise contains small quantities of aqueous vapour, and of car- bonic acid gas; and Lavoisier proved that this last body is itself a compound elastic fluid, consisting of charcoal dissolved in oxygene. Jethro Tull, in his treatise on Horse-hoeing, publish- ed in 1733, advanced the opinion that minute earthy particles supplied the whole nourishment of the vege- table world; that air and water were chiefly useful in producing these particles from the land; and that ma- nures acted in no other way than in ameliorating the texture of the soil, in short, that their agency was me- chanical. This ingenious author of the new system of agriculture having observed the excellent effects pro- duced in farming by a minute division of the soil, and the pulverisation of it by exposure to dew and air, was misled by carrying his principles too far. Duhamel, in a work printed in 1754, adopted the opinion of Tull, and. stated that by finely dividing the soil, any number of crops might be raised in succession from the same land. He attempted also to prove, by direct experi- ments, that vegetables of every kind were capable of 17 being raised without manure. ‘This celebrated horti- culturist lived, however, sufficiently long to alter his opinion. The results of his later and most refined ob- servations led him to the conclusion, that no single ma- terial afforded the food of plants. ‘The general expe- rience of farmers had long before convinced the unpre- judiced of the truth of the same opinion, and that ma- nures were absolutely consumed in the process of vege- tation. The exhaustion of soils by carrying off corn crops from them, and the effects of feeding cattle on lands, and of preserving their manure, offer familiar il- lustrations of the principles; and several philosophical inquirers, particularly Hassenfratz and Saussure, have shewn by satisfactory experiments, that animal and ve- getable matters deposited in soils are absorbed by plants, and become a part of their organized matter. But though neither water, nor air, nor earth, supplies the whole of the food of plants, yet they all operate in the process of vegetation. The soil is the laboratory in which the food is prepared. No manure can be taken up by roots ‘of plants unless water is present; and water or its ele- ments exist in all the products of vegetation. The ger- mination of seeds does not take place without the pre- sence of air of oxygene gas; and in the sunshine vegetables decompose the carbonic acid gas of the at- mosphere, the carbon of which is absorbed, and be- comes a part of their organized matter, and the oxygene gas, the other constituent, is given off; and in conse- quence of a variety of agencies, the economy of vege- tation is made subservient to the general order of the system of nature. It is shewn by various researches, that the constitu- tion of the atmosphere has been always the same since the time that it was first accurately analysed ; and this . must in a great measure depend upon the powers of -plants to absorb or decompose the putrifying or decay- ing remains of animals and vegetables, and the gaseous effluvia which they are constantly emitting. Carbonic acid gas is formed in a variety of processes of ferment- ation and combustion, and in the respiration of animals, and as yet no other process is known in nature by which it can be consumed, except vegetation. Animals pro- ( Vv 18 duce a substance which appears to be a necessary food of vegetables; vegetables evolve a principle necessary to the existence of animals; and these different classes of beings seem to be thus connected together in the ex- ercise of their living functions, and to a certain extent made to depend upon each other for their existence. Water is raised from the ocean, diffused through the air, and poured down upon the soil, so as to be applied to the purposes of life. ‘The different parts of the atmos- phere are mingled together by winds or changes of tem- perature, and successively brought in contact with the surface of the earth, so as to exert their fertilizing in- fluence. ‘The modifications of the soil, and the appli- cation of manures are placed within the power of man, as if for the purpose of awakening his industry and of calling forth his powers. The theory of the general operation of the more com- pound manures may be rendered very obvious by sim- ple chemical principles; but there is still much to be discovered with regard to the best methods of render- ing animal and vegetable substances soluble ; with re- spect to the processes of decomposition, how they may be accelerated or retarded, and the means of producing the greatest effects from the materials employed ; these subjects will be attended to in the Lecture on Manures. Plants are found by analysis to consist principally of charcoal and aeriform matter. ‘They give out by dis- tillation volatile compounds, the elements of which are pure air, inflammable air, coally matter, and azote, or that elastic substance which forms a great part of the atmosphere, and which is incapable of supporting com- bustion. These elements they gain either by their Jeaves from the air, or by their roots from the soil. All manures from organized substances contain the princi- ples of vegetable matter, which during putrefaction are rendered either soluble in water or aeriform—and in these states they are capable of being assimilated to the vegetable organs. No one principle affords the pabu- lum of vegetable life; it is neither charcoal nor hydro- gene, nor azote nor oxygene alone; but all of them to- gether in various states and various combinations. Or- ganic substances as soon as they are deprived of vitality, 19 begin to pass through a series of changes which ends in their complete destruction, in the entire separation and dissipation of the parts. Animal matters are the soonest destroyed by the operation of air, heat, and light. Vegetable substances yield more slowly, but finally obey the same laws. The periods of the appli- cation of manures from decomposing animal and vege- table substances depend upon the knowledge of these principles, and I shall be able to produce some new and important facts founded upon them, which I trust willremove all doubt from this part of agricultural theory. The chemistry of the more simple manures ; the ma- nures which act in very small quantities, such as gyp- sum, alkalies, and various saline substances, has hither- to been exceedingly obscure. It has been generally supposed that these materials act in the vegetable econo- my in the same manner as condiments or stimulants in the animal economy, and that they render the common food more nutritive. It seems, however, a much more probable idea, that they are actually a part of the true food of plants, and that they supply that kind of mat- ter to the vegetable fibre, which is analogous to the bony matter in animal structures. The operation of gypsum, it is well known, is ex- tremely capricious in this country, and no certain data have hitherto been offered for its application. There is, however, good ground for supposing that the subject will be fully elucidated by chemical inquiry. Those plants which seem most benefited by its appli- cation, are plants which always afford it on analysis. Clover, and most of the artificial grasses, contain it, but it exists in very minute quantity only in barley, wheat, and turnips. Many peat ashes which are sold at a considerable price, consist in great part of gypsum, with a little iron, and the first séems to be their most active ingredient. I have examined several of the soils to which these ashes are successfully applied, and I have found in them no sensible quantity of gypsum. In general, cultivated soils contain sufficient of this substance for the use of the grasses: in such cases, its application cannot be advantageous. For plants re- 20 quire only a certain quantity of manure; an excess may be detrimental, and cannot be useful. _ The theory of the operation of alkaline substances, is one of the parts of the chemistry of agriculture, most simple and distinct. ‘They are found in all plants, and therefore may bé regarded as amongst their essential ingredients. From their powers of combination like- wise, they may be useful in introducing various princi- ples into the sap of vegetables, which may be subservient to their nourishment. The fixed alkalies which were formerly regarded as elementary bodies, it has been my good fortune to de- compose. They consist of pure air, united to highly inflammable metallic substances ; but there is no reason to suppose that they are reduced into their elements in any of the processes of vegetation. In this part of the Course I shall dwell at considera- ble length on the important subject of Lime, and I shall be able to offer some novel views. Slacked lime was used by the Romans for manuring the soil in which fruit trees grew. This we are inform- ed by Pliny. Marle had been employed by the Bri- tons and the Gauls from the earliest times, as a top dressing for land. But the precise period in which burnt lime first came into general use in the cultivation of land, is, 1 believe, unknown. The origin of the ap- plication from the early practices is sufficiently obvious; a substance which has been used with success in gar- dening, must have been soon tried in farming; and in countries where marle was not to be found, calcined limestone would be naturally employed as a substitute. The elder writers on agriculture had no correct no- tions of the nature of lime, limestone and marle, or of their effects; and this was the necessary consequence of the imperfection of the chemistry of the age. Cal- careous matter was considered by the alchemists as a peculiar earth, which in the fire became combined with inflammable acid; and Evelyn and Hartlib, and, still later, Lisle, in their works on husbandry, have charac- terized it merely as a hot manure of use in cold lands. It is to Dr. Black of Edinburgh that our first distinct 2 rudiments of knowledge on the subject, are owing. About the year 1755, this celebrated professor proved, by the most decisive experiments, that limestone and all its modifications, marbles, chalks, and marles, con- sist principally of a peculiar earth united to an aerial acid: that the acid is given out in burning, occasioning a loss of more than 40 per cent., and that the lime in consequence becomes caustic. These important facts immediately applied with equal certainty to the explanation of the uses of lime, both as a cement and as a manure. As a cement, lime applied. in its caustic state acquires its hardness and durability, by absorbing the aerial (or as it has been since called carbonic) acid, which always exists in small quantities in the atmosphere, it becomes as it were again limestone. Chalks, calcareous marles, or powdered limestone, act merely by forming a useful earthy ingredient of the soil, and their efficacy is proportioned to the deficiency - of calcareous matter, which in larger or smaller quanti- ties seems to be an essential ingredient of all fertile soils; necessary perhaps to their proper texture, and as an ingredient in the organs of plants. Burnt lime, in its first effect, acts as a decomposing agent upon animal or vegetable matter, and seems to bring it into a state on which it becomes more rapidly a vegetable nourishment; gradually, however, the lime is neutralized by carbonic acid, and converted into a substance analogous to chalk; but in this case it more perfectly mixes with the other ingredients of the soil, is more generally diffused and finely divided : and it is probably more useful to land than any calcareous sub- stance in its natural state. The most considerable fact made known with regard to limestone within the last few years, is owing to Mr. Tennant. It had been long known that a particular species of limestone found in different parts of the North of England, when applied in its burnt and slack- ed state to land in considerable quantities, occasioned sterility, or considerably injured the crops for many years. Mr. Tennant in 1800, by a chemical examina- tion of this species .of limestone, ascertained, that it differed from common limestones by containing magne- 38 sian earth; and by several experiments he proved that this earth was prejudicial to vegetation, when applied in large quantities in its caustic state. Under common circumstances the lime from the magnesian limestone is, however, used in moderate quantities upon fertile soils in Leicestershire, Derbyshire, and Yorkshire, with good effect; and it may be applied in greater quantities to soils containing very large proportions of vegetable matter. Magnesia when combined with carbonic acid gas, seems not to be prejudicial to vegetation, and in soils rich in manure, it is speedily supplied with this principle from the decomposition of the manure. After this nature and operation of manures have been discussed, the next and the last subject for our conside- - ration, will be some of the operations of husbandry capable of elucidation by chemical principles. The chemical theory of fallowing is very simple. Fallowing affords no new source of “riches to the soil. It merely tends to produce an accumulation of decom- posing matter, which in the common course of crops would be employed as it is formed, and it is scarcely possible to imagine a single instance of a cultivated soil, which can be supposed to remain fallow for a year with advantage to the farmer. ‘The only cases where this practice is beneficial seems to be in the destruction of weeds, and for cleansing foul soils. The chemical theory of paring and burning, I shall discuss fully in this part of the Course. It is obvious that in all cases it must destroy a certain quantity of vegetable matter, and must be principally useful in cases in which there is an excess of this mat- ter in soils. Burning, likewise renders clays less co- herent, and in this way greatly improves their texture, and causes them to be less permable to water. The instances in which it must be obviously prejudi- cial, are those of sandy dry siliceous soils, containing little animal or vegetable matter. Here it can only be destructive, for it decomposes that on which the soil de- pends for its productiveness. The advantages of irrigation, though so lately a sub- ject of much attention, were well known to the ancients ; and more than two centuries ago the practice was re- Sind 4 23 commended to the farmers of our country by Lord Ba- con; “ meadow-watering,”’ according to the statements of this illustrious personage, (given in his Natural His- tory, in the article Vegetation,) acts not only by sup- plying useful moisture to the grass; but likewise the water carries nourishment dissolved in it, and defends the rovts from the effects of cold. No general principles can be laid down respecting .the comparative merit of the different systems of culti- vation, and the different systems of crops adopted in different districts, unless the chemical nature of the soil, and the physical circumstances to which it is exposed are fully known. Stiff coherent soils are those most benefited by minute division and aeration, and in the drill system of husbandry, these effects are produced to the greatest extent; but still the labour and expense connected with its application in certain districts, may not be compensated for by the advantages produced. Moist climates are best fitted for raising the artificial grasses, oats, and broad-leaved crops; stiff aluminous soils, in general, are most adapted for wheat crops, and calcareous soils produce excellent sain-foin and clover. Nothing is more wanting in agriculture, than experi- _ ments in which all the circumstances are minutely and | scientifically detailed. ‘This art will advance with ra- pidity in proportion as it becomes exact in its methods. As in physical researches all the causes should be con- sidered ; a difference in the results may be produced, even by the fall of a half an inch of rain more or less in the course of a season, or a few degrees of tempera- ture, or even by a slight difference in the sub-soil, or in the inclination of the land. Information collected after views of distinct inquiry, would necessarily be more accurate, and more capable of being connected with the general principles of science ; and a few histories of the results of truly phi- losophical experiments in agricultural chemistry, would be of more value in enlightening and benefiting the far- mer, than the greatest possible accumulation of imper- _ fect trials conducted merely in the empirical spirit. It is no unusual occurrence for persons who argue in fa- vour of practice and experience, to condemn generally 24 all attempts to improve agriculture by philosophical in- quiries and chemical methods. ‘That much vague spe- culation may be found in the works of those who haye lightly taken up agricultural chemistry, it is impossible to deny. It is not uncommon to find a number of chan- ges rung upon a string of technical terms, such as oxy- gene, hydrogene, carbon, and azote, as if the science de- pended upon words, rather than upon things. But this is in fact an argument for the necessity of the establish- ment of just principles of chemistry on the subject. Whoever reasons upon agriculture, is obliged to recur to this science. He feels that it is scarcely possible to advance a step without it: and if he is satisfied with insufficient views, it is not because he prefers them to . accurate knowledge, but generally because they are more current. If a person journeying in the night wishes to avoid being led astray by the ignis fatuus, the most secure method is to carry a lamp in his own hand. It has been said, and undoubtedly with great truth, that a philosophical chemist would most probably make a very unprofitable business of farming; and this cer- tainly would be the case, if he were a mere philosophical chemist; and unless he had served his apprenticeship to the practice of the art,-as well as the theory. But there is reason to believe, that he would be a more suc- cessful agriculturist than a person equally uninitiated in farming, but ignorant of chemistry altogether ; his science, as far as it went, would be usefultohim. But chemistry is not the only kind of knowledge required, it forms a small part of the philosophical basis of agri- culture; but it is an important part, and whenever ap- plied in a proper manner must produce advantages. In proportion as science advances all the principles become less complicated, and consequently more useful. And it is then that their application is most advanta- geously made to the arts. The common labourer can never be enlightened by the general doctrines of phi- losophy, but he will not refuse to adopt any practice, ef - the utility of which he is fully convinced, because it has been founded upon these principles. The mariner _ can trust to the compass, though he may be wholly un- 25 acquainted with the discoveries of Gilbert on magnet- ism, or the refined principles of that science developed by the genius of Zpinus. The dyer will use his bleach- ‘Ing liquor, even though he is perhaps ignorant not only of the constitution, but even of the name of the sub- stance on which its powers depend. ‘The great pur- pose of chemical investigation in Agriculture, ought un- doubtedly to be the discovery of improved methods of cultivation. But to this end, general scientific princi- ples and practical knowledge, are alike necessary. The germs of discovery are often found in rational specula- tions ; and industry is never so efficacious as when as- sisted by science. It is from the higher classes of the community, from the proprietors of land; those who are fitted by their education to form enlightened plans, and by their for- tunes to carry such plans into execution; it is from these that the principles of improvement must flow to the la- bouring classes of the community ; and in all cases the benefit is mutual; for the interest of the tenantry must be always likewise the interest of the proprietors of the soil. The attention of the labourer will be more minute, and he will exert himself more for improve- ment when he is certain he cannot deceive his employ- er, and has a conviction of the extent of his knowledge. Ignorance in the possessor of an estate of the manner in which it ought to be treated, generally leads either to inattention or injudious practices in the tenant or the bailiff. “ Agrum pessimum mulctari cujus Dominus non docet sed. audit villicum.”’ There is no idea more unfounded than that a sreat devotion of time, and a minute knowledge of ceneral chemistry is necessary for pursuing experiments on the nature of soils or the properties of manures. Nothing can be more easy than to discover whether a soil effer- yesces, or changes colour by the action of an acid, or whether it burns when heated ; or what weight it loses by heat: and yet these simple indications may be of great importance in a system of cultivation. The ex- pense connected with chemical inquiries is extremely trifling ; a small closet is sufficient for containing all the materials required. 'The most important experiments may be made by means of a small portable apparatus ; DY 26 a few phials, a few acids, a lamp and a crucible are all that are necessary, as I shall endeavour to prove to you, in. the course of these lectures. It undoubtedly happens in agricultural chemical ex- periments conducted after the most refined theoretical views, that there are many instances of failure, for one of success; and this is inevitable from the capricious and uncertain nature of the causes that operate, and from the impossibility of calculating on all the circum- stances that may interfere; but this is far from proving the inatility of such trials; one happy result which can generally improve the methods of cultivation is worth the labour of a whole life; and an unsuccessful expertiment well observed, must establish some truth, or tend to re- move some prejudice. Even considered merely as a philosophical science, this department of knowledge is highly worthy of cul- tivation. For what can be more delightful than to trace the forms of living beings and their adaptations and pe- culiar purposes; to examine the progress of inorganic matter in its different processes of change, till it attain its ultimate and highest destination ; its subserviency to the purposes of man. Many of the sciences are ardently pursued, and con- sidered as proper objects of study for all refined minds, merely on account of the intellectual pleasure they af-— ford ; merely because they enlarge our views of nature, and enable us to think more correctly with respect to the beings and objects surrounding us. How much more then is this department of inquiry worthy of at- tention, in which the pleasure resulting from the love of truth and of knowledge is as great as in any other branch of philosophy, and in which it is likewise con- nected with much greater practical benefits and advan- tages. “Nihil est melius, nihil uberius, nihil homine libero dignius.”’ Discoveries made in the cultivation of the earth, are not merely for the time and country in which they are developed, but they may be considered as extending to future ages, and as ultimately tending to benefit the whole human race: as affording subsistence for genera- tions yet to come; as multiplying life, and not only multiplying life, but likewise providing for its enjoyment. ee LECTURE I. Of the general Powers-of Matter which influence Ve- getation. Of Gravitation, of Cohesion, of Chemical Attraction, of Heat, of Light, of Electricity, ponder- able Substances, Elements of Matter, particularly those found in Vegetables, Laws of their Combina- tions and Arrangements. THE great operations of the farmer are directed to- wards the production or improvement of certain classes of vegetables ; they are either mechanical or chemical, and are, consequently, dependent upon the laws which govern common matter. Plants themselves are, to a certain extent, submitted to these laws; and it is neces- sary to study their effects, both in considering the phe- nomena of vegetation, and the cultivation of the vege- table kindom. ‘One of the most important properties belonging to matter is gravitation, or the power by which masses of matter are attracted towards each other. It is in con- sequence of gravitation that bodies thrown into the at- mosphere fall to the surface of the earth, and that the different parts of the globe are preserved in their pro- per positions. Gravity is exerted in proportion to the quantity of matter. Hence all bodies placed above the surface of the earth fall to it in right lines, which if produced would pass through its centre; and a body falling near a high mountain, is a little bent out of the perpendicular direction by the attraction of the moun- tain, as has been shewn by the experiments of Dr. Mas- kelyne on Schehallien. Gravitation has a very important influence on the growth of plants; and it is rendered probable, by the experiments of Mr. Knight, that they owe the peculiar direction of their roots and branches almost entirely to this force. That gentleman fixed some seeds of the garden bean 28 on the circumference of a wheel, which in one instance was placed vertically, and in the other horizontally, and made to revolve, by means of another wheel work- ed by water, in such a manner, that the number of the revolutions could be regulated ; the beans were supplied with moisture, and were placed under circumstances fa- vourable to germination. ‘The greatest velocity of mo- tion given to the wheel was such, that it performed two hundred and fifty revolutions in a minute. It was found that in all cases the beans grew, and that the direction of the roots and stems was influenced by the motion of the wheel. When the centrifugal force was made su- perior to the force of gravitation, which was supposed to be done when the vertical wheel performed 450 re- volutions in a minute, all the radicles, in whatever way they were protruded from the position of the seeds, turned their points outwards from the circumference of the wheel, and in their subsequent growth receded near- ly at right angles from its axis; the germens, on the contrary took the opposite direction, and in a few days their points all met in the centre of the wheel. When the centrifugal force was made merely to mo- dify the force of gravitation in the horizontal wheel, where the greatest velocity of revolution was given, the radicles pointed downwards about ten degrees below, © and the germens as many degrees above the horizontal line of the wheel’s motion ; and the deviation from the perpendicular was less in proportion, as the motion was less rapid.* These facts afford a rational solution of this curious problem, respecting which different philosophers have given such different opinions ; some referring it to the nature of the sap, as De la Hire, others, as Darwin, to the living powers of the plant, and the stimulus of air upon the leaves, and of moisture upon the roots. The effect is now shewn to be connected with mechanical causes; and there seems no other power in nature to which it can with propriety be referred but gravity, *Fig.\1, represents the form of the experiment when the horizon- tal wheel was made to perform 250 revolutions in a minute. Fig. 2, represents the case in which the vertical wheel performed 150 revolutions. 29 which acis universally, and which must tend to dispose the parts to take a uniform direction. If plants in general owe their perpendicular direction to gravity, it is evident that the number of plants upon a given part of the earth’s circumference, cannot be in- creased by making the surface irregular, as some per- sons have supposed. Nor can more stalks rise on a — hill than on a spot equel to its base; for the slight ef- fect of the attraction of the bill, would be only to make the plants deviate a:very little from the perpendicular. Where horizontal layers are pushed forth, as in certain grasses, particularly such as the fiorin, lately brought into notice by Dr. Richardson, more food may, however, be produced upon an irregular surface ; but the princi- ple seems to apply strictly to corn crops. The direction of the radicles and germens is such, that both are supplied with food, and acted upon by those external agents which are necessary for their de- velopment and growth. The roots come in contact with the fluids in the ground; the leaves are exposed to light and air; and the same grand law which preserves the planets in their orbits, is thus essential to the func- tions of vegetable life. When two pieces of polished glass are pressed to- gether they adhere to each other, ‘and it requires some force to separate them. ‘This is said to depend upon the attraction of cohesion. 'The same attraction gives the globular form to drops of water, and enables fluids to rise in capillary tubes; and hence it is sometimes called capillary attraction. 'This attraction, like gravi- tation, seems common to all matter, and may be a mo- dification of the same general force; like gravitation, it is of great importance in vegetation. It preserves the forms of aggregation of the parts of plants, and it seems to be a principal cause of the absorptions of fluids by their roots. If some pure magnesia, the calcined magnesia of druggists, be thrown into distilled vinegar, it sadually dissolves. This is said to be owing to chemical attrac- _tion, the power by which different species of matter tend to unite into one compound. Various kinds of matter unite with different degrees of force: thus sul- 30 “ge phuric acid and magnesia unite with more readiness than distilled vinegar and magnesia; and if sulphuric acid be poured into a mixture of vinegar and magnesia, in which the acid properties of the vinegar have been destroyed by the magnesia, the vinegar will be set free, and the sulphuric acid will take its place. This chemi- cal attraction is likewise called chemical affinity. Vt is active in most of the phenomena of vegetation. ‘The sap consists of a number of ingredients, dissolved in | water by chemical attraction; and it appears to be in consequence of the operation of this power, that certain principles derived from the sap are united to the vege- table organs. By the laws of chemical attraction, dif- ferent products of vegetation are changed, and assume’ new forms; the food of plants is prepared in the soil ; vegetable and animal remains are changed by the ac- tion of air and water, and made fluid or aeriform ; rocks are broken down and converted into soils; and soils are more finely divided and fitted as receptacles for the roots of plants. The different powers of attraction tend to preserve the arrangements of matter, or to unite them in new forms. If there were no opposing powers, there would soon be a state of perfect quiescence in nature, a kind of eternal sleep in the physical world. Gravitation is continually counteracted by mechanical agencies, by projectile. motion, or the, centrifugal force; and their joint agencies occasion the motion of the heavenly bodies. Cohesion and chemical attraction are opposed by the repulsive energy of heat, and the harmonious cycle of terrestrial changes is produced by their mutual operations. Heat is capable of being communicated from one body to other bodies; and its common effect is to expand them, to enlarge them in all their dimensions. This is easily exemplified. A solid cylinder of metal after be- ing heated will not pass through a ring barely sufficient to receive it when cold. When water is heated in a globe of glass having a long’slender neck, it rises in the neck ; and if heat be applied to air confined in such a vessel inverted aboye water, it makes its escape from the ves- sel and passes through the water. Thermometers are — instrnments for measuring degrees of heat by the ex- ° 4 * eh NRRL HET 3h pansion of fluids in narrow tubes. Mercury is general- ly used, of which 100,000 parts at the freezing point of water become 101,835 parts at the boiling point, and on Fahrenhvit’s scale these parts are divided into 180 de- grees. Solids, by a certain increase of heat, become fluids, and fluids gases, or elastic fluids. Thus ice is converted by heat into water, and by still more heat it becomes steam : and heat disappears, or, as it is called, is rendered Jatent during the conversion of solids into fluids, or fluids into gases, and re-appears or becomes sensible when gases become fluids, or fluids solids : hence cold is produced during evaporation, and heat during the condensation of steam. There are few exceptions to the law of expansion of bodies by heat, which seem to depend either upon some change in their chemical constitution, or on their be- coming ‘crystallized. Clay contracts by heat, which seems to be owing to its giving off water. Cast iron and antimony, when melted, crystallize in cooling and ex- pand. Iceis much lighter than water. Water expands _a little even before it freezes, and it is of the greatest density at about 41° or 42°, the freezing point being 32°; and this circumstance is of considerable importance in the general economy of nature. The influence of the changes of seasons and of the position of the sun on the phenomena of vegetation, demonstrates the effects of heat on the functions of plants. The matter absorbed from the soil must be in a fluid state to pass into their roots, and when the surface is frozen they can derive no nou- Tishment from it. The activity of chemical changes like- wise is increased by a certain increase of temperature, and even the rapidity of the ascent of fluids by capilla- ry attraction. This last fact is easily shewn by placing in each of two wine glasses a similar hollow stalk of grass, so bent as to discharge any fluid in the glasses slowly by capil- lary attraction ; if hot water be in one glass, and cold water in the other, the hot water will be discharged much more rapidly than the cold water. The fermen- _ tation and decomposition of animal and vegetable sub- _ stances require a certain degree of heat, which is conse- quently necessary for the preparation of the food of a2. i plants; and as evaporation is more rapid in proportion as the temperature is higher, the superfluous parts of the sap are most readily carried off at the time its ascent is quickest. ! Two opinions are current respecting the nature of heat. By some philosophers it is conceived to be a pe- culiar subtle fluid, of which the particles repel each other, but have a strong attraction for the particles of other matter. By others itis considered as a motion or vibra- tion of the particles of matter, which is supposed to dif- fer in velocity in different cases, and thus to produce the different degrees of temperature. Whatever decision be ultimately made respecting these opinions, it is certain that there is matter moving in the space between us and the heavenly bodies capable of communicating heat; the motions of which are rectilineal: thus the solar rays pro- duce heat in acting on the surface of the earth. The beautiful experiments of Dr. Herschel have shewn that there are rays transmitted from the sun which do not il+ _ luminate ; and which yet produce more heat than the vi- sible rays; and Mr. Ritter and Dr. Wollaston have shewn that there are other invisible rays distinguished by their chemical effects. The different influence of the different solar rays on vegetation have not yet been studied; but it is certain that the rays exercise an influence independent of the heat they produce. Thus plants kept in the dark in a hot-house grow luxuriantly, but they never gain their natural colours; their leaves are white or pale, and their juices watery and peculiarly saccharine. When a piece of sealing-wax is rubbed by a woollen cloth, it gains the power of attracting light bodies, such as feathers or ashes. In this state it is said to be elec- trical; and if a metallic cylinder, placed upon a rod of glass, is brought in contact with the sealing- wax, it like- wise gains the momentary power of attracting light bo- dies, so that electricity, like heat, is communicable. When two light bodies receive the same electrical in- fluence, or are electrified by the same body, they repel each other. When one of them is acted on by sealing- wax, and the other by glass that has been rubbed by woollen, they attract each other; hence it is said, that 33 bodies similarly electrified repel each other, and bodies dissimilarly electrified attract each other: and the elec- tricity of glass is called vitreous or positive electricity; and that of sealing-wax resinous or negative electri- city. When of two bodies made to rub each other one is found positively electrified, the other is always found negatively electrified, and, as in the common electrical machine, these states are capable of being communica- _ted to metals placed upon rods or pillars of glass. Elec- tricity is produced likewise by the contact of bodies; thus a piece of zinc and of silver give a slight electri- cal shock when they are made to touch each other, and to touch the tongue: and when a number of plates of copper and zinc, 100 for instance, are arranged ina pile ~ with cloths moistened in salt and water, in the order of zinc, copper, moistened cloth, zinc, copper, moistened ° cloth, and so on, they form an electrical battery which will give strong shocks and sparks, and which is possessed of remarkable chemical powers. ‘The luminous pheno- mena produced by common electricity are well known. It would be improper to dwell upon them in this place. They are the most impressive effects occasioned by this agent; and they offer illustrations of lightning and thunder. Electrical changes are constantly taking place in na- ture, on the surface of the earth, and in the atmosphere ; but as yet the effects of this power in vegetation have not been correctly estimated. It has been shewn by ex- periments made by means of the Voltaic battery (the in- struments composed of zinc, copper, and water) that com- pound bodies in general are capable of being decompo- sed by electrical powers, and it is probable, that the va- rious electrical phenomena occurring in our system, must influence both the germination -of seeds and the growth of plants. I found that corn sprouted. much more rapidly in water positively electrified by the Vol-: taic instrument, than in water negatively electrified ; and experiments made upon the atmosphere shew that clouds _are usually negative; and as when acloud is in one state - of electricity, the surface of the earth beneath is brought into the opposite state, it is probable that in common cases the surface of the earth is positive. E * 34 Different opinions are entertained amongst scientific men respecting the nature of electricity ; by some, the phznomena are conceived to depend upon a single sub- tile fluid in excess in the bodies, said to be positively electrified, in deficiency in the bodies said to be nega- tively electrified. A second class suppose the effects to be produced by two different fluids, called by them the vitreous fluid and the resinous fluid; and others regard them as affections or motions of matter, or an exhibition of attractive powers, similar to those which produce che- mical combination and decomposition ; but usually ex- erting their action on masses. The different powers that have been thus generally described, continually act upon common matter, so as to change its form, and produce arrangements fitted for the purposes of life. Bodies are either simple or compound. A body is said to be simple, when it is incapable of be- ing resolved into any other forms of matter. ‘Thus gold, or silver, though they may be melted by heat, or dissol- ved in corrosive menstrua, yet are recovered unchanged in their properties, and they are said to be simple bodies. A body is considered as compound, when two or more distinct substances are capable of being produced from it; thus marble is a compound body, for by a strong heat, it is converted into lime, and an elastic fluid is dis- engaged in the process : and the proof of our knowledge of the true composition of a body is, that it is capable of being reproduced by the same substances as those into which is had been decomposed; thus by exposing lime for a long while to the elastic fluid, disengaged during its calcination, it becomes. converted into a substance si- mnilar to powdered marble. ‘The term element has the — same meaning as simple or undecompounded body; but it is applied merely with reference to the present state of chemical knowledge. It is probable, that as yet we are not acquainted with any of the true elements of mat- ter; many substances, formerly supposed to be simple, have been lately decompounded, and the chemical ar- rangement of bodies must be considered as a mere ex- pression of facts, the results of accurate statical experi- ments. Vegetable substances in general are of a very com- | 35 pound nature, and consist of a great a a of elements, _ most of which belong likewise to the other kingdoms of nature, and are found in various forms. Their more complicated arrangements are best understocd after their simpler forms of combination have been examin- ed. The number of bodies which I shall consider as at present undecomposed, are, as was stated in the intro- ductory lecture, three acidifying and solvent substances, six inflammable bodies, and thirty-eight metals. In most of the inorganic compounds, the nature of which is well known, into which these elements enter, they are combined in definite proportions ; so that if the elements be represented by numbers, the proportions in which they combine are expressed either by those num- bers, or by some simple multiples of them. I shall mention, in a few words, the characteristic properties of the most important simple substances, and the numbers representing the proportions in which they combine in those cases, where they have been accurate- ly ascertained. 4. Oxygene forms about one-fifth of the air of our at- mosphere. It is an elastic fluid, at all known tempera- tures. Its specific gravity is to that of air as 10967 to 40000. It supports combustion with much more vivid- ness than common air; so that if a small steel wire, or a watch-spring, having a bit of inflamed wood attached to it, be introduced into a bottle filled with the gas, it burns with great splendour. It is respirable. It is very slightly soluble in water. ‘The number represent- ing the proportion in which it combines is 15. It may be made by heating a mixture of the mineral called man- ganese, and sulphuric acid together, in a proper vessel, or by heating strongly red lead, or red precipitate of mercury. _ 2. Chlorine, or oxymuriatic gas, is, like oxygene, a permanent elastic fluid. Its colour is yellowish green; its smell is very disagreeable ; it is not respirable ; it supports the combustion of all the common inflammable bodies except charcoal ; its specific gravity is to that of air as 24677 to 10000; it is soluble in about half its vo- lume of water, and its solution in water destroys vege- 36 table colours. Many of the metals (such as arsenic or copper) take fire spontaneously when introduced into a jar or bottle filled with the gas. Chlorine may be,pro- cured by heating together a mixture of spirits of salt or muriatic acid, and manganese. The number represent- | ing the proportion in which this gas enters into combi- nation is 67. 3. Fluorine, ox the fluoric principle. This substance has such strong tendencies of combination, that as yet, no vessels have been found capable of containing it in its pure form. It may be obtained combined. with hy- drogene, by applying heat to a mixture of fluor or Der- byshire spar, and sulphuric acid, and in this state it is an intensely acid compound, a little heavier than water, and which becomes still denser by combining with wa- ter. , 4. Hydrogene, or inflammable air, is the lightest known substance ; its specific gravity is to that of air as 732 to 10000. It burns by the action of an inflamed taper, when in contact with the atmosphere. The pro- portion in which it combines is represented by unity, or 4. It is procured by the action of diluted oil of vi- troil, or hydro-sulphuric acid on filings of zinc or iron. it is the substance employed for filling air balloons. 5. Azote is a gaseous substance, not capable of bemg condensed by any known degree of cold: its specific gravity is to that of common air as 9516 to 10000. It does not enter into combustion under common circum- stances, but may be made to unite with oxygene by the agency of electrical fire. It forms nearly four-fifths of the air of the atmosphere; and may be procured by burning phosphorous in a confined portion of air. The number representing the proportion in which it combines is 26. | 6. Carbon is considered as the pure matter of char- coal, and it may be procured by passing spirits of wine through a tube heated red. It has not yet been fused; but rises in vapour at an intense heat. Its specific gra- vity cannot be easily ascertained ; but that of the dia- mond, which cannot chemically be distinguished from pure carbon, is to that of water as 3500 to 1000. Char- coal has the remarkable property of absobing several 37 times its volume of different elastic fluids, which are ca- pable of being expelled from it by heat. ‘he number representing it is 14.4. : 7. Sulphur is the pure substance so well known by that name: its specific gravity is to that of water as _ 4990 to 1000. It fuses at about 220° Fahrenheit; and — at between 500° and 600° takes fire, if in contact with the air, and burns with a pale blue flame. In this pro- cess it dissolves in the oxygene of the air, and produces a peculiar acid elastic fluid. ‘The number representing ‘itis 30. 8. Phosphorus is a solid of a pale red colour, of spe- cific gravity 1770. It fuses at 90°, and boils at 550°. It is luminous in the air at common temperatures, and burns with great violence at 150°, so that it must be handled with great caution. The number represent- ing it is 20. It is procured by digesting together bone ashes and oil of vitroil, and strongly heating the fluid substance so produced with powdered charcoal. 9. Boron is a solid of a dark olive colour, infusible at any known temperature. It is a substance very late- ly discovered, and procured from boracic acid. It burns with brilliant sparks, when heated in oxygene, but not in chlorine. Its specific gravity and the number repre- senting it, are not yet accurately known. 10. Platinum is one of the noble metals, of rather a duller white than silver, and the heaviest body in na- ture ; its specific gravity being 21500. It is not acted upon by any acid menstrua except such as contain chlorine: it requires an intense degree of heat for its fu- sion. 11. he properties of gold are well known. Its spe- cific gravity is 19277. It bears the same relation to acid menstrua as platinum: it is one of the characteris- tics of both these bodies, that they are very difficultly acted upon by sulphur. 12. Silver is of specific gravity 10400, it burns more readily than platinum or gold, which require the intense heat of electricity. Lt readily unites to sulphur. The number representing it is 205. 13. Mercury is the only known metal fluid at the common temperature of the atmosphere ; it boils at 660°. 38 and freezes at 39 below 0. Its specific gravity is 13560- The number representing it is 380... | 44. Copper is of specific gravity 8890. It burns when strongly heated with red flame tinged with green. The number representing it is 120. | 45. Cobalt is of specific gravity 7700. Its point of fusion is very high, nearly equal to that of iron. In its calcined or oxidated state, it is employed for giving a blue colour to glass. 46. Nickel is of a white colour: its specific gravity is 8820. This metal and cobalt agree with iron, it be- ing attractible by the magnet. ‘The number representing | nickel is 114. : | 17. fron is of specific gravity 7700. Its other pro- perties are well known. 'The number representing it is 103. 48. Tin is of specific gravity 7291 ; it is a very fusi- ble metal, and burns when ignited in the air: the num- ber representing the proportion in which it combines is 110. 49. Zinc is one of the most combustible of the com- mon metals. Its specific gravity is about 7210. It is a brittle metal under common circumstances; but when heated may be hammered or rolled into thin leaves, and after this operation is malleable. The number repre- senting it is 66. | 20. Lead is of specific gravity 11352; it fuses at a temperature rather higher than tin. ‘The number re- presenting it is 398. ; 21. Bismuth is a brittle metal of specific gravity 9822. It is nearly as fusible as tin; when cooled slow- | ly it crystallizes in cubes. The number representing — it is 135. 22. Antimony is a metal capable of being volatilized by a strong heat. Its specific gravity is 6800. It burns when ignited with a faizt white light. ‘The number re- presenting it is 470. 23. rsenic is of a bluish white colour, of specific gravity 8310. It may be procured by heating the pow- der of common white arsenic of the shops strongly in a Florence flask with oil. The metal rises in vapour, and condenses in the neck of the flask. The number representing it is 90. 39 24. Manganesum may be procured from the mineral called manganese, by intensely igniting it in a forge mixed with charcoal powder. It is a metal very diffi- cult of fusion, and very combustible ; its specific gravi- ty is 6850. The number representing it is 177. 25. Potassium is the lightest known metal, being only of specific gravity 850. It fuses at about 150°, and rises in vapour at a heat a little below redness. ii is a highly combustible substance, takes fire when thrown upon water, burns with great brilliancy, and . the product of its combustion dissolves in the water, The number representing it is 75. It may be made by passing fused caustic vegetable alkali, the pure kali of druggists, through iron turnings strongly ignited in a gun barrel, or by the electrization of potash by a strong Voltaic batter y- 26. Sodium may be made in a similar manner to po- tassium. Soda, or the mineral alkali, being substituted for the vegetable alkali. It is of specific gravity 940. It is very combustible. When thrown upon water, it swims on its surface, hisses violently, and dissolves, but does not inflame. The number represeuting it is 88. 27. Barium has as yet been procured only by elec- trical powers and in very minute quantities, so that its properties have not been accurately examined. ‘The number representing it appears to be 130. Strontium the 28, Calcium the 29th, Magnesium the 30th, Silicum the 31st, Aluminum the 32d, Zirco- num the 33d, Glucinum the 34th, and Ittrium the 35th of the undecompounded bodies, like barium, have either not been procured absolutely pure, or only in such mi- nute quantities that their properties are little known; they are formed either by electrical powers, or by the agency of potassium, from the different earths whose names they bear, with the change of the termination in um; and the numbers representing them are believed to be 90 strontium, 40 calcium, 38 magnesium, 31 sili- cum, 33 aluminum, 70 zirconum, 39 glucinum, 4111 it- trium. Of the remaining simple bodies, twelve are metals, most of which, like those just mentioned, can only be procured with very great difftculty; and the substances in 40 general from which they are procured are very rare in nature. They are Palladium, Rhodium, Osmium, Iri- dium, Columbium, Chromium, Molybdenum, Cerium, Tellurium, Tungstenum, Titanium, Uranium. The numbers representing these last bodies have not yet been determined with sufficient accuracy to render a refer- ence to them of any utility. The undecompounded substances unite with each other, and the most remarkable compounds are formed _by the combinations of oxygene and chlorine with in- flammable bodies and metals; and these combinations usually take place with much energy, and are associated with fire. Combustion in fact, in common cases, is the process of the solution of a body in oxygene, as happens when sulphur or charcoal is burnt; or the fixation of oxygene by the combustible body in a solid form, which takes place when most metals are burnt, or when phosphorus inflames ; or the production of a fluid from both bodies, as when hydrogene and oxygene unite to form water. When considerable quantities of oxygene or of chlo- rine unite to metals or inflammable bodies, they often produce acids: thus sulphureous, phosphoric, and bo- racic acids are formed by a union of considerable quan- tities of oxygene with sulphur, phosphorus, and boron : and muriatic acid gas is formed by the union of chlorine and hydrogene. When smaller quantities of oxygene or chlorine unite ° with inflammable bodies or metals, they form substances not acid, and more or less soluble in water; and the metallic oxides, the fixed alkalies, and the earths, all bodies connected by analogies, are produced by the union of metals with oxygene. The composition of any compounds, the nature of which is well known, may be easily learnt from the numbers representing their elements; all that is neces- sary, is to know how many proportions enter into union. Thus potassa, or the pure caustic vegetable alkali, con-_ sists of one proportion of potassium and one of oxygene, and its constitution is consequently 75 potassium, 15 oxygene. Carbonic acid is composed of two proportions of oxy- gene 30, and one of carbon 41.4. chi Again, lime consists of one proportion of calcium and one of oxygene, and it is composed of 40 of cal- cium and 15 of oxygene. And corbonate of lime, or pure chalk, consists of one proportion of carbonic acid 41.4, and one of lime 55. Water consists of two proportions of hydrogene 2, and one of oxygene 15; and when water unites to other bodies in definite proportions, the quantity is 47, or some multiple of 17, 7. e. 34 or 54, or 68, &c. Soda, or the mineral alkali, contains two proportions of oxygene to one of sodium. Ammonia, or the volatile alkali, is composed of six proportions of hydrogene and one of azote. Amongst the earths, Silica, or the earth of flints, pro- bably consists of two proportions of oxygene to one of silicum; and Magnesia, Strontia, Baryta or Barytes, Alumina, Zircona, Glucina, and Ittria, of one propor- tien of metal and one of oxygene. The metallic oxides in general consist of the metals united to from one to four proportions of oxygene ; and. there are, in some cases, many different oxides of the same matal; thus there are three oxides of lead; the yellow oxide, or massicot, contains two proportions of oxygene ; the red oxide, or minium, three ; and the puce coloured oxide four proportions. Again there are two oxides of copper, the black and the orange; the black contains two proportions of oxygene, the orange one. For pursuing such experiments on the composition of bodies as are connected with agricultural chemistry, a few only of the undecompounded substances are ne- _cessary ; and amongst the compounded hodies, the com- mon acids, the alkalies, and the earths, are the most es- sential substances. ‘I'he elements found in vegetables, as has been stated in the introductory lecture, are-very few. Oxygene, hydrogene, and carbon, constitute the greatest part of their organized matter. Azote, phos- phorus, sulphur, manganesum, iron, silicum, calcium, aluminum, and magnesium likewise, in different ar- rangements, enter into their composition, or are found in the agents to which they are exposed ; and these twelve undecompounded substances are the elements, the study F 42 of which is of the most importance to the agricultural chemist. The doctrine of definite tbrin thine oes as will be shewn in the following lectures, will assist us in gaining just views respecting the composition of plants, and the economy of the vegetable kingdom; but the same ac- curacy of weight and measure, the same statistical re- sults which depend upon the uniformity of the laws that govern dead matter, cannot be expected in operations where the powers of life are cencerned, and where a diversity of organs and of functions exists. ‘The class- es of definite inorganic bodies, even if we include all. the crystalline arrangements of the mineral kingdom, are few, compared with the forms and substances be- longing to animated nature. Life gives a peculiar char- acter to all its productions ; the power of attraction and repulsion, combination and decomposition, are subser- vient to it; a few elements, by the diversity of their arrangement, are made to form the most different sub- stances; and similar substances are produced from compounds, which, when superficially examined, ap- pear entirely different. LECTURE IIL On the Organization of Plants. Of the Roots, Trunk, and Branches. Of their Structure. Of the Epider- mis. Of the cortical and alburnous Parts of Leaves, Flowers, and Seeds. Of the chemical Constitution of the Organs of Plants, and the Substances found in them. Of mucilaginous, saccharine, extractive, resinous, and oily Substances, and other vegetable Compounds, their Arrangements in the Organs of Plants, their Composition, Changes, and Uses. VARIETY characterises the vegetable kingdom, yet . there is an analogy between the forms and the functions of all the different classes of plants, and on this analo- sy the scientific principles relating to their organization depend. Vegetables are living structures distinguished from animals by exhibiting no signs of perception, or of yo- luntary motion; and their organs are either organs of nourishment or of reproduction; organs for the preser- vation and increase of the individual, or for the multi- plication of the species. In the living vegetable system there are to be consi- dered, the exterior form, and the interior, constitution. Every plant examined as to external structure, dis- plays at least four systems of organs, or some analo- gous parts. Wirst, the Root ; secondly, the Trunk and Branches, or Stem ; thirdly, the Leaves ; and fourthly, _ the Flowers or Seeds. The root is that part of the vegetable which least impresses the eye; but it is absolutely necessary. It attaches the plant to the surface, is its organ of nourish- ment, and the apparatus by which it imbibes food from the soil. The roots of plants, in their anatomical di- vision, are very similar to the trunk and branches. The root may indeed be said to be a continuation of the trunk terminating in minute ramifications and filaments, and 44 not in leaves: and by burying the branches of certain trees in the soil, and elevating the roots in the atmos- phere, there is, as it were, an inversion of the functions, the roots produce buds and leaves, and the’ brances shoot out into radical fibres andtubes. This experiment was made by Woodward on the willow, and has been repeated by a number af physiologists. When the branch or the root of a tree is cut trans- vetsely, it usually exhibits three distinct bodies: the bark, the wood, and the pith; and these again are in- dividually susceptible of a new division. The bark when perfectly formed, is covered by a thi cuticle or epidermis, which may be easily separated. ‘It is generally composed of a number of lamine or scales, which in old trees are usually in a loose and de- caying state. ‘The epidermis is not vascular, and it merely defends the interior -parts from injury. In fo- rest trees, and in the larger shrubs, the bodies of which are firm, and of strong texture, it is a part of little im- portance; but in the reeds, the grasses, canes, and the plants having hollow stalks, it is of great use, and is exceedingly strong, and in the microscope seems com- posed of a kind of glassy net-work, which is princi- pally siliceous earth. This is the case in wheat, in the oat, in different spe- cies of equisetum, and above all, in the rattan, the epi-— dermis of which contains a sufficient quantity of flint to give light when struck by steel; or two pieces rub- bed together produce sparks. his fact first occurred to me in 1798, and it led to experiments, by which I ascertained that siliceous earth existed generally in the epidermis of the hollow plants. The siliceous epidermis serves as a support, protects the bark from the action of insects, and seems to per- form a part in the economy of these feeble vegetable tribes, similar to that performed in the animal kingdom, by the shell of the crustaceous insects. Immediately beneath the epidermis is the parenchy- ma. It is a soft substance consisting of cells filled with fluid, having almost always a greenish tint. ‘The cells in the parenchymatous part, when examined by the mi- croscope, appear hexagonal. ‘L'his form, indeed, is that usually affected by the cellular membranes in vegeta- 45 bles, and it seems to be the result of the general re-ac- tion of the solid parts, similar to that which takes place in the honey-comb. This arrangement, which has — usually been ascribed to the skill and artifice of the bee, seems as Dr. Wollaston has observed, to be merely the result of the mechanical laws which influence the pres- sure of cylinders composed of soft materials, the nests of solitary bees being uniformly circular. The innermost part of the bark is constituted by the cortical layers, and their numbers vary with the age of the tree. On cutting the bark of a tree of several years standing, the productions of different periods may be distinctly seen, though the layer of every particular year can seldom be accurately defined. The cortical layers are composed of fibrous parts which appear interwoven, and which are transverse and longitudinal. ‘The transverse are membraneous and porous, and the longitudinal are generally composed of tubes. The functions of the parenchymatous and cortical parts of the bark are of great importance. ‘The tubes of the fibrious parts appear to be the organs that receive the sap; the cells seem destined for the elaboration of its parts, and for the exposure of them to the action of the atmosphere, and the new matter is annually produ- ced in the spring, immediately on the inner surface of the cortical layer of the last year. It has been shewn by the experiments of Mr. Knight, and those made by other physiologists, that the sap de- scending through the bark after being modified in the leaves, is the principal cause of the growth of the tree ; thus, if the bark is wounded, the principal formation of new bark is on the upper edge of the wound; and when the wood has been removed, the formation of new wood takes place immediately beneath the bark : yet it would appear from the late observations of M. Palisot de Beauvois, that the sap may be transferred to the bark, so as to exert its nutritive functions, indepen- dent of any general system of circulation. That gentle- man separated different portions of bark from the rest of the bark in several trees, and found that in most in- _ stances the separated bark grew in the same manner as the bark in its natural state. The experiment was tri- 46 ed with most success on the lime-tree, the maple, and the lilac; the layers of bark were removed in August 1810, and in the spring of the next year, in the case of the maple and the lilac, small annual shoots were pro- duced in the parts where the bark was insulated.* The wood of trees is composed of an external or li- ving part, called alburnum, or sap-wood, and of an in- ternal or dead part, the heart-wood. The alburnum is white, and full of moisture, and in young trees and an- nual shoots it reaches even to the pith. "he alburnum is the great vascular system of the vegetable through which the sap rises, and the vessels in it extend from the leaves to the minutest filaments in the roots. There is inthe alburnuma membranous substance com- posed of cells, which are constantly filled with the sap of the plant, and there are in the vascular system seve- ral different kind of tubes; Mirbel has distinguished four species, the simple tubes, the porous tubes, the tra- chee, and the false trachew.t The tubes, which he has called simple tubes, seem to contain the resinous or oily fluids peculiar to differ- ent plants. The porous tubes likewise contain these fluids; and their use is probably that of conveying them into the sap for the production of new arrangements. The trachee contain fluid matter, which is always thin, watery, and pellucid, and these organs, as well as the false tracheex, probably carry off water from the denser juices, which are thus enabled to consolidate for the production of new wood. In the arrangement of the fibres of the wood, there are two distinct appearances. There are series of white and shining lamine which shoot from the centre towards the circumference, and these constitute what is called the silver grain of the wood. There are likewise numerous series of concentric lay- ers which -are usually called the spurious grain, and their number denotes the age of the tree.t * Fig. 3, represents the result of the experiment on the maple. Journal de Physique, Septemher 1811, page 210. t+ Fig. 4, 5, 6, and 7, represent Mirbel’s idea of the simple tubes, the porous tubes, the trachez, and the false trachez. } Fig. 8, represents the section of an elm branch, which exhibits A7 The silver grain is elastic and contractile, and it has been supposed by Mr. Knight, that the change of volume produced in it by change of temperature is one of the principal causes of the ascent of the sap. The fibres of it seem always to expand in the morning, and contract at night; and the ascent of the juices, as was stated in the last Lecture, depends principally on the agency of heat. The silver grain is most distinct in forest trees; but even annual shrubs have a system of fibres similar to it. The analogy of nature is constant and uniform, and si- milar effects are usually produced by similar organs. The pith occupies the centre of the wood; its texture is membranous ; it is composed of cells, which are cir- cular towards the extremity, and hexagonal in the cen- tre of the substance. In the first infancy of the vegeta- ble, the pith occupies but a small space. It gradually dilates, and, in annual shoots and young trees offers a considerable diameter. In the more advanced age of the tree, acted on by the heart-wood, pressed by the new layers of the alburnum, it begans to diminish, and in very old forest trees disappears altogether. Many different opinions have prevailed with regard to the use of the pith. Dr. Hales supposed, that it was the great cause of the expansion and developement of the other parts of the plant; that being the most interi- or, it was likewise the most acted upon of all the or- gans, and that from its re-action the phenomena of their developement and growth resulted. Linneus, whose lively imagination was continually employed in endeavours to discover analogies between the animal and vegetable systems, conceived “that the pith performed for the plant the same functions as the brain and nerves in animated beings.”” He considered it as the organ of irritability and the seat of life. The latest discoveries have proved that these two opinions are equally erroneous. Mr. Knight has remo- ved the pith in several young trees, and they continued to live and to increase. ; _ the tubular structure and the silver and spurious grain. Fig. 9, re- _ presents the section of part of the branch of an oak. Fig. 10, that of the branch of an ash, 48 lt is evidently then only an organ ef secondary im- portance. In early shoots, in vigorous growth, it is fill- ed with moisture, and it is a reservoir, perhaps, of fluid nourishment at the time itis most wanted. As the heart- wood forms, it is more and more separated from the li- ving part, the alburnum; its functions become exstinct, it diminishes, dies, and at last disappears. The tendrils, the spines, and other similar parts of plants, are analogious in their organization to the branch- es, and offer a similar corticle and alburnous organiza- tion. It has been shewn, by the late observations of Mr. Knight, that the directions of tendrils, and the spi- ral form they assume, depend upon the unequal action of light upon them, and a similar reason has been -as- signed by M. Decandolle to account for the turning of the parts of plants towards the sun; that ingenious phy- siologist supposes that the fibres are shortened by the chemical agency of the solar rays upon them, and that, consequently, the parts will move towards the light. The leaves, the great sources of the permanent beau- ty of vegetation, though infinately diversified in their - forms, are in all cases similar in interior organization, and perform the same functions. ‘The alburnum spreads itself from the foot-stalks into the very extremity of the leaf; it retains a vascular sys- tem and its living powers ; and its peculiar tubes, par-- ticularly the trachee, may be distinctly seen in the leaf.* The green membranous substance may be considered as an extension of the parenchyma, and the fine and thin covering as the epidermis. Thus the organization of the roots and branches may be traced into the leaves, — which present, however, a more perfect, réfined, and minute structure. One great use of the leaves is, for the exposure of the — sap to the influence of the air, heat, and light. ‘Their surface is extensive, the tubes and cells very delicate, and their texture porous and transparent. -- Jn the leaves much of the water of the sap is evapo- * Fig. li, represents part of a leaf of a vine magnified and cut, so | _as to exhibit the trachez ; it is copied, as are also the preceding fig~ ures, from Grew’s Anatomy of Plants. oe se Oey | ge ee 49 | rated ; it is combined with new principles, and fitted for its organizing functions, and probably passes, in its pre- pared state, from the extreme tubes of the alburnum in-- to the ramifications of the cortical tubes, and then de- scends through the bark. On the upper surface of leaves, which is exposed to the sun, the epidermis is thick but transparent, and is composed of matter possessed of little organization, which is either principally earthy, or consists of some homogenous chemical substance. In the grasses it is i) . e e e =) e _ partly siliceous, in the laurel resinous, and in the ma- ple and thorn, it is principally constituted by a substance analogious to wax. By these arrangements any evaporation, except from the appropriated tubes, is prevented. On the lower surface the epidermis is a thin transpa- rent membrane full of cavities, and it is probably alto- gether by this surface that moisture and the principles - of the atmosphere necessary to vegetation are absorb- ed. | | If a leaf be turned, so as to present its lower surface to the sun, its fibres will twist so as to bring it as much as possible into its original position; and all leaves ele- vate themselves on the foot-stalk during their exposure to the solar light, and as it were move towards the sun. This effect seems in a great measure dependent upon the mechanical and chemical agency of. light and heat. Bonnet made artificial leaves, which, when a moist sponge was held under the lower sarface, and a heated iron above the upper surface, turned exactly in the same man- ner as the natural leaves. This however can be consider- ed only as a very rude imitation of the natural process. What Linneus has called the sleep of the leaves, ap- pears to depend wholly upon the defect of the action of light and heat, and the excess of the operation of mois- ture. This singular but constant phenomenon, had never been scientifically observed, till the attention of the bo- tanist of Upsal was fortunately directed to it. He was examining particularly a species of lotus, in which four _ flowers had appeared during the day, and he missed two in the evening; by accurate inspection, he soon discoyer- G 50 ed that these two were hidden by the leaves which had closed round them. Such a circumstance could not be lost upon so acute an observer. He immediately took a lantern, went into his garden, and witnessed a series of curious facts before unknown. All the simple leaves of © the plants he examined, had an arrangement totally dif- ferent from their arrangement in the day : and the greater number of them were seen closed or folded together. The sleep of leaves is, in some cases, capable of be- ing produced artificially. Decandolle made this experi- ment on the sensitive plant. By confining it in a dark place in the day time, the leaves soon closed ; but onil- © luminating the chamber with many lamps, they again ex- anded. So sensible were they to the effects of light and radiant heat. | In the greater number of plants the leaves annually decay, and are repruduced; their decay takes place ei- ther at the conclusion of the summer, as in very hot cli- © mates, when they are no longer supplied with sap, in consequence of the dryness of the soil, and the evapo- rating powers of heat; or in the autumn, as in the north- ern climates at the commencement of the frosts. The leaves preserve their functions in common cases no long- er than there is acirculation of fluids through them. In the decay of the leaf, the colour assumed seems to de- pend upon the nature of the chemical change, and as acids are generally developed, it is usually either red- dish brown or yellow; yet there are great varieties. Thus in the oak, it is a bright brown; in the beech, orange; in the elm, yellow; in the vine, red; in the sy- - camore, dark brown; in the cornel tree, purple; and in the woodbine, blue. _ The cause of the preservation of the leaves of ever- greens through the winter is not accurately known. From the experiments of Hales, it appears that the force of the sap is much less in plants of this species, and pro- bably there is a certain degree of circulation throughout the winter; their juices are less watery than those of other plants, and probably less liable to be congealed by cold, and-they are defended by stronger coatings from the action of the elements. ‘The production of the other parts of the plant takes 4 / i “| 54 piace at the time the leaves are most vigorously perform- ing their functions. If the leaves are stripped off from a tree in spring, it uniformly dies, and when many of the leaves of forest trees are injured by blasts, the trees al- ways become stag-headed and unhealthy. _ ‘The leaves are necessary for the existence of the in- dividual tree, the flowers for the continuance of the spe- cies. Of all the parts of plants they are the most refi- ned, the most beautiful in their structure, and appear as the master-work of nature in the vegetable kingdom. -The elegance of their tints, the variety of their forms, the delicacy of their organization, and the adaptation of their parts are all calculated to awaken our curiosity, and excite our admiration. In the flower there are to be observed, 1st, the calyx, or the green membranous part forming the support for the coloured floral leaves. This is vascular, and agrees with the common leaf in its texture and organization ; it defends, supports, and nourishes the more perfect parts. 2d. The corolla, which consists either of a sin- gle piece, when it is,called monopetalous, or of many pieces, when it is called polypetalous. It is usually very vivid in its colours, is filled with an almost infinite variety of small tubes of the porous kind; it encloses and defends the essential parts in the interior, and sup- plies the juices of the sap to them. ‘These parts are, 3d, the stamens and the pistils. ‘he essential part of the stamens are the summits or anthers, which are usually circular and of a highly vas- cular texture, and covered with a fine dust called the allen. The pistil is cylindrical, and surmounted by the style ; the top of which is generally round and protuberant.* In the pistil, when it is examined by the microscope, congeries of spherical forms may usually be perceived, which seem to be the basis of the future seeds. It is upon the arrangement of the stamens and the pis- tils that the Linnzan classification is founded. The numbers of the stamens and pistils in the same flower, their arrangements, or their division in different flowers, * Fig. 12, represents the common lily, a, the corolla, 64564, the anthers, c, the pistil. 52 ave the circumstances which guided the Swedish philo- sopher, and enabled him to form a system admirably - adapted to assist the memory, and render botany of easy acquisition: and which, though it does not always as- sociate together the plants most analogous to each in their general characters, is yet so ingeniously contrived - as to denote a!l the analogies of their most essential parts. The pistil is the organ which contains the rudiments of the seed; but the seed is never formed as a repro- ductive germ, without the influence of the pollen, or dust on the anthers. This mysterious impressicn is necessary to the con- tinued succession of the different vegetable tribes. It is a feature which extends the resemblances of the dif- ferent orders of beings, and establishes, on a great scale, the beautiful analogy of nature. The ancients had observed, that different date trees bore different flowers, and that those trees producing flowers which contained pistils bore no fruit, unless in the immediate vicinity of such trees as produced flow- ers containing stamens. This long established fact strongly impressed the mind of Malpighi, who ascer- tained several analogous facts with regard to other ve- getables. Grew, however, was the first person who at- tempted to generalize upon them, and much just rea- soning on the subject may be found in his works. | Lin- neus gave a scientific and distinct form to that which Grew had only generally observed, and has the glory of establishing what has beencalled the sexual system, upon the basis of minute observations and accurate experiments. The seed, the last production of vigorous vegetation, is wonderfully diversified in form. Being of the high- est importance to the resources of nature, it is defend- ed above all other parts of the plant; by soft pulpy sub- stances, as in the esculent fruits, by thick membranes, as in the leguminous vegetables, and by hard shells, or a thick epidermis, as in the palms and grasses. In every seed there is to be distinguished, 4, the or- gan of nourishment ; 2, the nascent plant, or the plume ; 3, the nascent root, or the radicle. In the common garden bean, the organ of nourish- ment is divided into two lobes called cotyledons ; the ——— a ae > _——S is a Py ig the = 2 elem oF 53 plume is the small white point between the upper part of the lobes; and the radicle is the small curved cone at their base.* In wheat, and in many of the grasses, the organ of nourishment is a single part, and these plants are call- ed monocotyledonous: In other cases it consists of more than two parts, when the plants are called polycotyledo- nous. In the greater number of instances it is, how- ever, simply divided into two, and is sleigh The matter of the seed, when examined in its com- mon state, appears dead and imert; it exhibits neijher the forms nor the functions of life. But let it be acted upon by moisture, heat, and air, and its organized pow- ers are soon distintly developed. ‘The cotyledons ex- pand, the membranes burst, the radicle acquires new matter, descends into the soil, and the plume rises to- wards the free air. By degrees, the organs of nourish- ment of dicotyledonous plants become vascular, and are converted into seed leaves, and. the perfect plant ap- pears above the soil. Nature has provided the elements of germinations on every part of the surface ; water and pure air and heat are universally active, and the means for the preservation, and multiplication of life, are at once simple and grand. To enter into. more minute details on the vegetable physiology would be incompatable with the objects of these Lectures. I have attempted only to give such ge- neral ideas on the subject, as may enable “the philoso- phical agriculturist to understand the functions of plants ; those who wish to study the anatomy of vegetables, as a distinct science, will find abundant materials in the works of the authors [ have quoted, page, 13, and like- wise in the writings of Linnzus, Desfontaines, Decan- dolle, de Saussure, Bonnet, and Smith. The history of the peculiarities of structure in the different vegetable classes, rather belongs to botanical than agricultural knowledge. As [ mentioned in the commencement of this Lecture, their organs are pos- sessed of the most distinct analogies, and are governed * Fig. 13, represents the garden bean, aa, the cotyledons, 4, the plume, c, the radicle. UR eo a4 by the same jaws. In the orasses and palms, the cor- | tical layers are larger in proportion than the other parts ; but their uses seem to be the same as in forest trees. Jn bulbous roots, the alburnous substance forms the largest part of the vegetable; but in all cases it seems to contain the sap, or solid materials deposited from the _ sap. and the cedar perform the same functions as the lar ee and juicy leaves of the fig-tree or the walnut. — , Even in the cryptogamia, where no flowers are dis- tinct, still there is every reason to believe that the pro- — duction of the seed is effected in the same way as in the more perfect plants. ‘The mosses and lichens, ‘which belong to this family, have no distinct leaves or roots, but they are furnished with filaments which perform the same functions ; and even in the fungus and the mushroom there is a system for the absorption and aeration of the sap. i was stated in the last Lecture, that all the different parts of the plants are capable of being decomposed into a few elements. ‘heir uses as food, or for the purpo- ses of the arts, depend upon compound arrangements of . those elements which are capable of being produced ei- ther from their organized parts, or from the juices they contain; and the examination of the nature of these sub- stances, is an essential part of Agricultural Chemis- try. Oils are expressed from the fruits of many plants; resinous fluids exude from the wood; saccharine mat- ters are afforded by the sap; and dyeing materials are furnished by leaves, or the petals of flowers: but par- ticular processes are necessary to separate the different compound vegetable substances from each other, such as maceration, infusion or digestion in water, or in spirits of wine: but the application and the natare of these pro- cesses will be better understood when the chemical na- -ture of the substances is known; the consideration of ‘them will therefore be reserved for another place in this Lecture. The compound substances found in vegetables are, 4, gum, or mucilage, and its different modifications: 2, The slender and comparatively dry leaves of the a i, Wit aa Me em 5d starch; 3, sugar; 4, albumen; 5, gluten; 6, gum elas- tic; 7, extract; 8, tannin ; 9, indigo; 10, narcotic princi- ple; 14, bitter principle ; 12, Wax3 13, resins ; 44, cam- phor; 15, fixed oils; 16, volatile oils; 17, woody fibres 18, acids ; 19, ik sling earths; miekaltn oxides, and saline compounds. I shall describe generally the properties and compo- sition of these bodies, and the manner in which they are . procured. 1. Gum is a substance which exudes from certain trees ; it appears in the form of a thick fluid, but soon . hardens in the air, and becomes solid; when it is white; or yellowish white, more or less transparent, and some- what brittle; its specific gravity varies from 1300 to 1490. There is a great variety of gums, but the best known are gum arabic, gum senegal, gum tragacanth, and the gum of the plum or cherry tree. Gum is soluble in wa- ter, but not soluble in spirits of wine. If a solution of gum be made in water, and spirits of wine or alcohol be added to it, the gum separates in the form of white flakes. Gum can be made to inflame only with difficul- ty; much moisture is given off in the process, which takes place with a dark smoke and feeble blue flame, and a coal remains. The characteristic properties of gum are its easy so- lubility in water, and its insolubility in alcohol. Dif- ferent chemical substances have been proposed for as- certaining the presence of gum, but there is reason to believe that few of them afford accurate results; and most of them (particularly the metallic salts,) which pro- duce changes in solutions of gum, may be conceived to act rather upon some saline compounds existing in the gum, than upon the pure vegetable principle. Dr. Thomson has proposed an aqueous solution of silica in potassa, as a test of the presence of gum in solutions he states that the gum and silica are “precipitated toge- ther—this test, however, cannot be applied with cor- rect results in cases when acids are present. Mucilage must be considered as a variety of gum; it agrees with it in its most important properties, but seems to ltave less attraction for water.—According to enti stadt, when gum and mucilage are disealvadt together i1 hy ei De 56 water, the mucilage may be separated by means of sul- phuric acid—mucilage may be procured from linseed, from the bulbs of the hyacinth, from the leaves of the marshmallows ; from several ef the lichens, and from many other vegetable substances. From the analysis of M. M. Gay Lussac and The- nard, it appears that gum arabic contains in 100 parts: of carbon - - 42,23 —oxygene 4 “ 50,84 -—hydrogene— - - 6,93 with earthy matter a small quantity of saline and. or of carbon - - 42,23 oxygene and hydrogene in the proportions ne-$ 57,77 cessary to form ne This estimation agrees very nearly with the definite proportions of 14 of carbon, 10 of oxygene, and 20 of hydrogene. All the varieties of gum and. mucilage are nutritious as food. They either partially or wholly lose their so- lubility in water by being exposed to a heat of 500° or 600° Fahrenheit, but their nutritive powers are not de- stroyed unless they are decomposed. Gum and muci- lage are employed in some of the arts, particularly in calico-printing: till lately, in this country, the calico- printers used gum arabic; but many of them, at the sug- gestion of Lord Dundonald, now employ the mucilage from lichens. 2. Starch is procured from different vegetables, but particularly from wheat or from potatoes. ‘To make starch from wheat, the grain is steeped in cold water till it becomes soft, and yields a milky juice by pressure ; it is then put into sacks of linen, and pressed in a vat filled with water : as long as any milky juice exudes the pressure is continued ; the fluid gradually becomes clear, and a white powder subsides which is starch. Starch is soluble in boiling water, but not in cold wa- ter, nor in spirits of wine. According to Dr. ‘Thomson, — it is a characteristic property of starch to be: soluble in — a. warin infusion of nutgalls, and to form a precipitate when the infusion cools. Starch is more readily combustible than gum; when — hy ! \ ’ v PM k's ke aeRO OMT CECE Ue Ye cy 0 te han, naan sai h N , ANN He \ xs ty hilt Wi Me 1) Bn BO RM? TN mms ra AY remy pele: UN ca le ie Warm ; a (lt il sm said ae i Pa ha Pious OMEN Pete RM Neat ste SS Ca Pah Pe The. pele EPA ores rs FP RL oe a PF, Ms ae, INT ; 57 thrown upon red hot iron, it burns with a kind of ex- plosion, and scarcely any residuum remains. Accord- ing to Mr. Gay Lussac and Thenard, 100 parts of starch are composed of Carbon, with a small quan- ; tity of saline and earthy > 43,55 matter - : = Oxygene : - - 49,68 Hydrogene Wainy. - 6,77 or, Carbon - - - - 43,55 Oxygene and hydrogene in the proportions necessary > 56,45 to form water - - Supposing this estimation correct, starch may be con- ceived to be constituted by 15 proportions of carbon, 43 of oxygene, and 26 of hydrogene. Starch forms a principal part of a number of escu- lent vegetable substances. Sowans, cassava, salop, sa- go, all of them owe their nutritive powers principally to the starch they contain. Starch has been found in the following plants : Burdock (Arctium Lappa,) Deadly Nightshade (./4é- ropa Belladonna,) Bistort (Polygonum Bistorta,) White Bryony (Bryonia alba,) Meadow Saffron (Colchicum autumnale,) Dropwort (Spirwa Filipendula,) Buttercup (Ranunculus bulbosus,) Figwort (Scrophularia nodosa, ) Dwarf Elder (Sambucus Ebulus,) Common Elder (Sambucus nigra,) Kool-stones (Orchis Morio,) Alex- anders (Imperatoria Ostruthium,) Henbane (Hyoscya- mus niger,) Broad-leaved Dock (Rumex obtustfolius,) Sharp-pointed Dock (Rumex acutus,) Water Dock (Rumex aquaticus,) Wake Robin (rum maculaium,) Salep (Orchis mascula,) Flower de luce or Water flag (Iris Pseudacorus) Stinking Gladwyn (Iris feetidissi- ma,) Karthnut (Bunium Bulbocastanum.) 3. Sugar in its purest state is prepared from the ex- pressed juice of the Saccharum officinarum, or sugar cane; the acid in this juice is neutralized by lime, and the sugar is crystallized by the evaporation of the aque- H 58 ous parts of the juice, and slow-cooling: it is rendered — white by the gradual filtration of water through‘it. In the common process of manufacture, the whitening or refining of sugar is only effected in a great length of time; the water being gradually suffered to percolate through a stratum of clay above the sugar. As the co- louring matter of sugar is soluble in a saturated solu- tion of sugar, or syrup, it appears that refining may be much more rapidly and ceconomically performed by the action of syrup on coloured sugar.* The sensible pro- perties of sugar are well known. Its specific gravity, according to Fahrenheit, is about 4.6. It is soluble in its own weight of water at 50°; it is likewise soluble in alcohol, but in smaller proportions. Lavoisier concluded from his experiments, that sugar consists in 400 parts of } 28 carbon, 8 hydrogene, 64 oxygene. Dr. Thompson considers 100 parts of sugar as com- posed of 27,5 carbon, 7,8 hydrogene, 64,7 oxygene. According to the recent experiments of Gay Lussac and Thenard, sugar consists of 42,47 of carbon, and 57,53 of water or its elements. Lavoisier’s and Dr. Thomson’s analysis agree very nearly with the proportions of 3 of carbon, 4 of oxygene, and 8 of hydrogene. * A French gentleman lately in this country, stated to the West India planters, that he was in possession of a very expeditous and eco- nomical method of purifying and refining sugar, which he was willing to communicate to them for a very great pecuniary compensation. His terms were too high to be acceded to. Conversing on the sub-, ject with-Sir Joseph Banks, I mentioned to him, that I thought it probable that raw sugar might be easily purified by passing syrup through it, which would dissolve the colouring matter. The same idea seems to have occurred about the same time, or before, to Ed- ward Howard, Esq. who has since proved its efficacy experimentally, and has published an account of his process. 59 Gay Lussac’s and Thenard’s estimation gives the same elements as in gum; 44 of carbon, 10 of oxygene. 20 of hydrogene. It appears from the experiments of Proust, Achard, Goettling, and Parmentier, that there are many differ- ent species of sugar ready formed in the vegetable king- dom. The sugar which most nearly resembles that of the cane is extracted from the sap of the American ma- ple, Acer Saccharinum. ‘This sugar is used by the North American farmers, who procure it by a kind of domestic manufacture. ‘The trunk of the tree is bored early in spring, to the depth of about two inches: a wooden spout is introduced into the hole ; the juice flows for about five or six weeks. A common sized tree, that is, a tree from two to three feet in diameter, will yield about 200 pints of sap, and every 40 pints of sap afford about a pound of sugar. The sap is neutralized by lime, and deposits crystals of sugar by evaporation. The sugar of grapes has been lately employed in France as a substitute for colonial sugar. It is procur- ed from the juice of ripe grapes by evaporation, and the action of potashes ; it is less sweet than common sugar, and its taste is peculiar: it produces a sensation of cold while dissolving in the mouth; and it is probable con- tains a larger proportion of water or its elements. The roots of the beet (Beta vulgaris and cicla,) af- ford a peculiar sugar, by boiling, and evaporation of the extract: it agrees in its general properties with the su- gar of grapes, but has a slightly bitter taste. Manna, a substance which exudes from various trees, particularly from the Fraxinus Ornus, a species of ash, which grows abundantly in Sicily and Calabria, may be regarded as a variety of sugar, very analogous to the sugar of grapes. A substance analogous to manna has been extracted by Fourcroy and Vauquelin, from the juice of the common onion (Allium Cepa.) Besides the crystallized and solid sugars, there ap- pears to be a sugar which cannot be separated from wa- ter, and which exists only in a fluid form; it constitutes a principal part of molasses or treacle; and it is found in a variety of fruits: and it is more soluble in alcohol than solid sugar. i ; / ¢ Wenyy ATU yh Sole a) GR 60 ‘The simplest mode of detecting sugar is that recom- mended by Margraaf. The vegetable is to be boiled — in a small quantity of alcohol; solid sugar, if any exist, will separate during the cooling of the solution. Sugar has been extracted from the following vegeta- ble supstances : The sap of the Birch (Betula alba,) of the Sycamore (Acer Pseudoplatanus,) of the Bamboo (.4rundo Bam- — bos.) of the Maize (4ea mays,) of the Cow Parsnip — (Heracleum Sphondylium,) of the Cocoa-nut tree (Co- cos nucifera,) of the Walnut tree (Juglans alba,) of the American Aloe (Agave mericana,) of the Dulse (Fucus palmatus,) of the Common Parsnip (Pastinica sativa,) of St. John’s Bread (Ceratonia Siliqua,) the fruit of the Common Arbutus (Arbutos Unedo,) and other sweet tasted fruits; the roots of the turnip (Brassica Rapa,} of the Carrot (Daucus Carota,) of Parsley (Apium pet- roselinum,) the flower of the Euxine Rhododendron (Rhododendron ponticum,) and from the nectarium of most other flowers. ‘The nutritive properties of sugar are well known. Since the British market has been over-stocked with this article from the West India islands, proposals have been made for applying it as the food of cattle ; experi- ments have been made, which prove that they may be fattened by it; but difficulties connected with the duties laid on sugar, have hitherto prevented the plan from beind tried to any extent. 4. Albumen is a substance which has only lately been. discovered in the vegetable kingdom. It abounds in” the juice of the papaw-tree (Caryca Papaya:) when this juice is boiled, the albumen falls down in a coagu- lated state. It is likewise found in mushrooms, and in different species of funguses. Hi Albumen in its pure form, is a thick, glairy, tasteless fluid ; precisely the same as the white of the egg 5 it is soluble in cold water ; its solution, when not too diluted, is coagulated by boiling, and the albumen separates in the form of thin flakes. Albumen is likewise coagula- ted by acids and by alcohol: a solution of albumen gives a precipitate when mixed with a cold solution of — nut-galls. Albumen, when burnt, produces a smell of — 6L volatile alkali, and affords carbonic acid and water; it is therefore eyidently principally composed of carbo hydrogene, oxygene, and azote. According to the experiments of Gay Lidaaee and Thenard, 100 parts of albumen from the white of the egg are composed of Carbon a Vis OL - 52,883 Oxygene - 5 - 23,872 Hydrogene - - 7,540 Azote - - - 45,705 This estimation would authorise the supposition, that albumen is composed of 2 proportions of azote, 5 oxy- gene, 9 carbon, 22 hydrogene. The principal part of the almond, and of the kernels of many other nuts, appears from the experiments of Proust, to be a substance analogous to coagulated al: bumen. The juice of the fruit of the ochra (Hibiscus oscil tus,) according to Dr. Clarke, contains a liquid albu- men in such quantities, that it is employed in Domini- ca as a substitute for the white of eggs in clarifying the juice of the sugar-cane. Albumen may be distinguished from other substances by its property of coagulating by the action of heat or acids, when dissolved in water. According to Dr. Bos- tock, when the solution contains only one grain of albu- men to 1000 grains of water, it becomes cloudy by be- ing heated. Albumen is a substance common to the animal as well as to the vegetable kingdom, and much more abundant in the former. 5. Gluten may be obtained from wheaten flour by the following process: the flour is to be made into a paste, which is to be cautiously washed, by kneading it under a small stream of water, till the water has carried off from it all the starch; what remains is gluten. Itis a tenacious, ductile, elastic substance. It has no taste. By exposure to air it becomes of a brown colour. It is very slightly soluble in water; but not soluble in alco- hol. When a solution of it in water is heated, the glu- ten separates in the form of yellow flakes; in this res- pect it agrees with albumen, but differs from it in being ‘infinitely less soluble in water. ‘The solution of albu- 62 men does not coagulate when it contains much less — than 1000 parts of albumen; but it appears that gluten requires more than 1000 parts of cold water for its so- lution. Gluten, when burnt, affords similar products to albu- men, and probably differs very little from it in composi- tion. Gluten is found in a great number of plants; Proust discovered it in acorns, chesnuts, horse-chesnuts, apples, and quinces ; barley, rye, peas, and beans; likewise in the leaves of rue, cabbage, cresses, hemlock, borage, saf- fron, in the berries of the elder, and in the grape. Glu- ten appears to be one of the most nutritive of the vege- table substances ; and wheat seems to owe its superiori- ty to other grain, from the circumstance of its contain- ing it in larger quantities. 6. Gum elastic, or Caoutchouc, is procured from the juice of a tree which grows in the Brazils, called He- vea. When the tree is punctured, a milky juice exudes from it, which gradually deposits a solid substance, and this is gum elasic. Gum elastic is pliable and soft like leather, and be- comes softer when heated. In its pure state it is white ; its specific gravity is 9335. Itis combustible, and burns with a white flame, throwing off a dense smoke, with a very disagreeable smell. It is insoluble in water, and in alcohol; it is soluble in ether, volatile oils, and in petroleum, and may be procured from ether in an unal- tered state by evaporating its solution in that liquid. Gum elastic seems to exist in a great variety of plants : amongst them are, Jatropha elastica, Ficus indica, Ar- tocarpus integrifolia, and Urceola elastica. Bird-lime, a substance which may be procured from the holly, is very analogious to gum elastic in its pro- perties. Species of gum elastic may be obtained from the misletoe, from gum-mastic, opium, and from the ber- ries of the Smilaw caduca, in which last plant it has been lately discovered by Dr. Barton. Gum elastic when distilled, affords volatile alkali, water hydrogene, and carbon in different combinations. It therefore consists principally of azote, hydrogene, oxygene, and carbon; but the proportions in which they are combined have not yet been ascertained. Gum elas- a 63 tic is an indigestible substance, not fitted for the food of animals; its uses in the arts are well known. 7. Extract, or the extractive principle, exists in al- most all plants. It may be procured in a state of tole- rable purity from saffron, by merely infusing it in water, and evaporating the solution. It may likewise be ob- tained from catechu, or Terra japonica, a substance brought from India. This substance consists principal- ly of astringent matter, and extract; by the action of wa- ter upon it, the astringent matter is first dissolved, and may be separated from the extract. Extract is always more or less coloured; it is soluble in alcohol and water, but not soluble in ether. It unites with alumina when that earth is boiled in a solution of extract; and it is precipitated by the salts of alumina, and by many me- tallic solutions, particularly the solution of muriate of tin. . From the products of its distillation, it seems to be composed principally of hydrogene, oxygene, carbon, and a little azote. There appears to be almost as many varieties of ex- tract as there are species of plants. The difference of their properties probably, in many cases, depends upon their being combined with small quantities of other ve- getable principles, or to their containing different saline, alkaline, acid, or earthy ingredients. Many dyeing sub- stances seem to be of the nature of extractive principle, such as the red colouring matter of madder, and the yel- low dye, procured from weld. Extract has a strong attraction for the fibres of cotton or linen, and combines with these substances when they are boiled in a solution of it. The combination is made stronger by the intervention of mordants, which are earthy or metallic combinations that unite to the cloth, and enable the colouring matter to adhere more strongly to its fibres. | Extract in its pure form cannot be used as an article of food, but it is probably nutritive when united to starch, mucilage or sugar. 8. Tannin, or the tanning principle, may be procured by the action of a small quantity of cold water on bruised grape-seeds, or pounded gall-nuts; and by the evapora- 64 tion of the solution to dryness. It appears as a yellow 5 _ substance, possessed of a highly astringent taste. It is difficult of combustion. [Et is very soluble both in wa- ter and alcohol, but insoluble im ether. When a solu- tion of glue, or isinglass (gelatine,) is mixed with an . aqueous solution of tannin, the two substances, 1. e. the animal and vegetable matters fall down in combination, and form an insoluble precipitate. When tannin is distilled in close vessels, the princi- pal products are charcoal, carbonic acid, and inflamma- ble gases, with a minute quantity of volatile alkali. Hence its elements seem the same as those of extract, but probably in different proportions. The characteris- tic property of tannin is its action upon solutions of isin- glass or jelly; this particularly distinguishes it from ex- tract, with which it agrees in most other chemical qua-. lities. _ There are many varieties of tannin, which probably owe the difference of their properties to combinations with other principles, especially extract, from which it — | is not easy to free tannin. ‘The purest species of tannin is that obtained from the seeds of the grape; this forms a white precipitate, with solution of isinglass. ‘The tan- nin from gall-nuts resembles it in its properties. That from sumach affords a yellow precipitate ; that from ki- no a rose coloured; that from catechu a fawn coloured one. The colouring matter of Brazil wood, which M. Chevreul considers as a peculiar principle, and which he has called Hematine, differs from other species of tan- nin, in affording a precipitate with gelatine, which is so- luble in abundance of hot water. Its taste is much sweeter than that of the other varieties of tannin, and if may, perhaps, be regarded as a substance intermediate between tannin and extract. Tannin is not a nutritive substance, but is of great im- portance in its application to the art of tanning. Skin consists almost entirely of jelly or gelatine, in an organi- zed state, and is soluble by the long continued action of boiling water. When skin is exposed to solutions con- taining tannin, it slowly combines with that principle ; its fibrous texture and coherence are preserved; it is rendered perfectly insoluble in water, and is no longer — . | : ry 6A en ve cortiagih) ist ahontty Ce Serb) ( a ) ep MR A ee Pe i) oe We hae dee | : 65 liable to putrefaction: in short, it becomes a substance in chemical composition precisely analogous to that _ furnished by the solution of jelly and the solution of tannin. In general, in this country, the bark of the oak is used for affording tannin in the manufacture of leather ; but the barks of some other trees, particularly the Spanish » chesnut, have lately come into use. The following ta- ble will give a general idea of the relative value of dif- ferent species of barks. It is founded on the result of experiments made by myself. Table of Numbers exhibiting the quantity of Tannin afforded by 480lbs. of different Barks, which express nearly their relative Values. r ——— Average of entire bark of middle-sized Oak, cut in ! spring - - | of Spanish Chesnut - of Leicester Willow, large size o - of Common Willow, large of Ash - - - of Beech - - of Horse Chesnut : of Sycamore - b of Lombardy Poplar ——$ —_ —____—__——_ of Birch - - of Hazel - - of Black Thorn of Coppice Oak of Oak cut in autumn of Larch cut in autumn White interior cortical layers of Oak Bark — - The quantity of the tanning principle in barks dif- fers in different seasons ; when the spring has been very _ cold the quantity is smallest. On an average, four or five pounds of good oak bark are required to form one _ pound of leather. The inner cortical layers in all barks _ contain the largest quantity of tannin. Barks contain I 66 8 the greatest proportion of tannin at the time the buds begin to open—the smallest quantity in winter. The extractive or colouring matters found in barks, — or in substances used in tanning, influence the quality — of leather. ‘Thus skin tanned with gall-nuts is much paler than skin tanned with oak bark, which contains a brown extractive matter. Leather made from catechu is of a reddish tint. It is probable that in the process of tanning, the matter of skin, and the tanning princi- ple first enter into union, and that the leather at the mo- ment of its formation unites to the extractive matter. In general, skins in being converted into leather in- crease in weight about one third ;* and the operation is most perfect when they are tanned slowly. When skins are introduced into very strong infusions of tannin, the ~ exterior parts immediately combine with that principle, and defend the interior parts from the action of the so- lution: such leather is liable to crack and to decay by the action of water. The precipitates obtained from infusions containing tannin by isinglass, when dried, contain at a medium rate about 40 per cent. of vegetable matter. It is easy to obtain the comparative value of different substances for the use of the tanner, by comparing the quantities of precipitate afforded by infusions of given weights mixed with solutions of glue or isinglass. To make experiments of this kind, an ounce or 480 grains of the vegetable substance in coarse powder, should be acted upon by half a pint of boiling water. se ge ee aor ae SS The mixture should be frequently stirred, and suffered _ to stand 24 hours; the fluid should then be passed through ‘a fine linen cloth and mixed with an equal quantity of solution of, gelatine, made by dissolving glue, jelly, or isinglass in hot water, in the proportion of a drachm of glue or isinglass, or six table spoonfuls of jelly, to a pint of water. ‘The precipitate should be collected by. passing the mixture of the solution and infusion through folds of blotting paper; and the paper exposed to the air till its contents are quite dry. If pieces of paper * This estimation must be considered as applying to dry skin and dry leather. ver 67 of equal weights are used, in cases in which diiferent vegetable substances are employed, the difference of the weights of the papers when dried, will indicate with tolerable accuracy, the quantities of tannin contained by the substances, and their relative value, for the purposes of manufacture. Four tenths of the increase of weight, in grains, must be taken, which will be in relation to the weights in the table. Besides the barks already mentioned, there are a num- ber of others which contain the tanning principle. Few barks indeed are entirely free from it. It is likewise found in the wood and leaves of a number of trees and shrubs, and is one of the most generally diffused of the vegetable principles. A substance very similar to tannin has been formed by Mr. Hatchett, by the action of heated diluted nitric acid on charcoal, and evaporation of the mixture to dryness. From 100 grains of charcoal Mr. Hatchett obtained 120 grains of artificial tannin, which, like na- tural tannin, possessed the property cf rendering skin insoluble in water. _ Both natural and artificial tannin form compounds with the alkalies and the alkaline earths; and these compounds are not decomposable by skin. ‘The attempts that have been made to render oak bark more efficient as a tanning material by infusion in lime water, are con- sequently founded on erroneous principles. Lime forms with tannin, a compound not soluble in water. The acids unite to tannin, and produce compounds that are more or less soluble in water. It is probable that in some vegetable substances tannin exists, combi- ned with alkaline or earthy matter; and such substan- ces will be rendered more efficacious for the use of the tanner, by the action of diluted acids. 9. Indigo may be procured from woad (Isatis tincto- ria,) by digesting alcohol on it, and evaporating the so- lution. White crystalline grains are obtained, which ~ gradually become blue by the action of the atmosphere : these grains are the substance in question. The indigo of commerce is principally brought from America. It is procured from the Indigofera argentea, or wild indigo, the Indigofera disperma, or Gantimala + : al ys “ : ches ie er res) indigo, and the Indigofera tinctoria, or French indigo. | lt is prepared by fermenting the leaves of those trees in water. Indigo in its common form appears as a fine, deep blue powder. It is insoluble in water, and but slightly soluble in alcohol: its true solvent is sulphuric acid: eight parts of sulphuric acid dissolve one part of indigo; and the solution diluted with water forms a very fine blue dye. Indigo, by its distillation, affords carbonic acid gas, water, charcoal, ammonia, and some oily and acid mat- ter: the charcoal is in very large proportion. Pure in- digo therefore most probably consists of carbon, hydro- gene, oxygene, and azote. Indigo owes its blue colour to combination with oxy- gene. “For the uses of the dyers it is partly deprived of oxygene, by digesting it with orpiment and lime wa- ter, aca it becomes soluble in the lime water, and of a greenish colour. Cloths steeped in this solution com- | bine with the indigo ; they are green when taken out of the liquor, but become blue by absorbing oxygene when exposed to air. Indigo is one of the most valuable and most extensive- ly used of the dyeing materials. 10. The narcotic principle is found abundantly in opium, which is obtained from the juice of the white pop- py (Papaver album.) To procure the nar cotic principle, water is digested upon opium: the solution obtained is evaporated till it becomes of the consistence of a syrup. By the addition of cold water to this syrup a precipitate is obtained. Alcohol is boiled on this precipitate ; du- ring the cooling of the alcohol crystals fall down. These crystals are to be again dissolved in alcohol, and again precipitated by cooling: and the process is to be repeat- ed till their colour is white; they are crystals of narco- tic principle. The narcotic principle has no taste nor smell. It is soluble in about 400 parts of boiling water ; it is insolu- ble in cold water: it is soluble in 24 parts of boiling alcohol, and in 100 parts of cold alcohol. 4tis very soluble in all acid menstrua. It has been shewn by De Rosne, that the action of opium on the animal economy depends on this principle. : cot ne. Many other substances besides the juice of the poppy, _ possess narcotic properties ; but they have not yet been examined with much attention. ‘The Lactuta sativa, or garden lettuce, and most of the other lactucas yield a milky juice, which when inspissated has the charac- ters of opium, and probably contains the same narcolic principle. 41. The bitter principle is very extensively diffused in the vegetable kingdom ; it is found abundantly in the hop (Humilus lupilus,) in the common broom (Spartium scoparium,) in the chamomile (4nthemis nobilis,) and in quassia, amara and excelsa. It is obtained from those substances by the action of water or alcohol, and eva- poration. It is usually of pale yellow colour; its taste is intensely bitter. It is very soluble, both in water and alcohol; and has little or no action on alkaline, acid, saline, or metallic solution. An artificial substance, similar to the bitter principle, has been obtained by digesting diluted nitric acid, on silk, indigo, and the wood of the white willow. This substance has the property of dyeing cloth of a bright yellow colour ; it differs from the natural bitter princi- ple in its power of combining with the alkalies: in union with the fixed alkalies it constitutes crystallized bodies, which haye the property of detonating by heat or percussion. The natural bitter principle is of great importance in the art of brewing; it checks fermentation, and pre- serves fermented liquors; it is likewise used in medicine. The bitter principle, like the narcotic principle, ap- pears to consist principally of carbon, hydrogene and oxygene, with a little azote. 42. Was is found in a number of vegetables; it is procured in abundance from the berries of the wax myr- tle (Myrica cerifera-:) it may be likewise obtained from the leaves of many trees; in its pure state it is white. Its specific gravity is 9,662; it melts at £55 degrees ; it is dissolved by boiling alcohol; but it is not acted upon by cold alcohol; it is insoluble in water; its properties a a combustible body are well known. : The wax of the vegetable kingdom seems to be pre- cisely of the same nature as that afforded by the hee. i ae i" eC ae _ From the experiments of M. M. Gay Lusgac and The- _nard, it appears that 100 parts of wax consist of . Gerben -) e : - 81,784 Oxygene - LB - 5,544 Hydrogene - - - 12,672 Or otherwise, Carbon - - 81,784 Oxygene and bids ogene in the proportions necessary to form 6,300 water - - “ tude Hydrogene - - - 11,916 which agrees very nearly with 37 proportions of hydro- gene, 21 of charcoal, one of oxygene. 43. Resin is very common in the vegetable kingdom. One of the most usual species is that afforded by the dif- ferent kinds of fir. When a portion of the bark is re- moved from a fir tree in spring, a matter exudes, which is called turpentine ; by heating this turpentine gently, a volatile oil rises from it, and ¢ a more fixed substance remains, this substance is resin. The resin of the fir is the substance commonly known by the name of rosin; its properties are well known. Its specific gravity is 1072. It melts readily, burns | with a yellow light, throwing off much smoke. Resin is insoluble in water, either hot or cold; but very solu- ble in alcohol. When a solution of resin in alcohol is mixed with water, the solution becomes milky ; the re- sin is deposited by the stronger attraction of the a for the alcohol. Resins-are obtained from many other species of ides WMastich, from the Pistachia lentiscus, Elemi from the “myris elemifera, Copal from the Rhus copallinum, San- darach from the common juniper. Of these resins copal — is the most peculiar. It is the most difficultly dissolved in alcohol; and for this purpose must be exposed to that substance in vapour; or the alcohol employed must hold camphor in solution. According to Gay Lussac and Thenard, 400 parts of common resin contain ~ Carbon =e des - . 75,944 Oxygene - - aM: 13,337 Hydrogene > - : 10,719 or of ‘ r PARDON 9 oy ess - 75,944 _ Oxygene and hydrogene in cm proportions necessary to form> 415,156 water aah - Hydrogene in excess - 8,900 . consist of Carbon - - - - 76,814 Oxygene - - ; ~ 10,606 Hydrogene - - - 12,583 or, Carbon - - - - 76,814 Water or its elements - 12,052 Hydrogene > - - 11,137 From these results if resin be a definite compound, it may be supposed to consist of eight proportions of car- bon, twelve of hydrogene, and one of oxygene. Resins are used for a variety of purposes. "Var and pitch principally consist of resin, in a partially decom- posed state. ‘lar is made by the slow combustion of the fir; and pitch by the evaporation of the more volatile parts of tar. Resins are employed as varnish, and for these purposes are dissolved in alcohol or oils. Copal forms one of the finest. It may be made by boiling it ‘in powder with oil of rosemary, and then adding alco- hol to the solution. 14. Camphor is procured by distilling the wood of the camphor tree (Laurus camphora,) which grows in Ja- pan. It isa very volatile body, and may be purified by distillation. Camphor is a white, brittle, semitrans- parent substance, having a peculiar odour, and a strong acrid taste. It is very slightly soluble in water; more than 100,000 parts of water are required to dissolve one part of camphor. It is very soluble in alcohol ; and by adding water in small quantities at a time to the solu- tion of camphor in alcohol, the camphor separates in a Atte | SB According to the same chemists, 100 parts of copal = . | t iv ae crystallized form. It is soluble in nitric acid, and is se- _ parated from it by water. Camphor is very inflammable ; it burns with a bright flame, and throws off a great quantity of carbonaceous matter. It forms in combustion water, carbonic acid, and a peculiar acid called camphoric acid. No accur rate analysis has been made of camphor, but it seems to approach to the resins in its composition ; and consists of carbon, hydrogene, and oxygene. Camphor exists in other plants besides the Laurus camphora. tis procured from species of the laurus growing in Sumatra, Borneo, and other of the East Indian isles. It has been obtained from thyme (Thy- mus serpillum,( marjorum (Origanum majorana,) Gin- ger tree (dmomum Zingiber,) Sage (Salvia officina- lis.) Many volatile oils yield camphor by being mere- ly exposed to the air. An artificial substance very similar to camphor has been formed by M. Kind, by saturating oil of turpen- tine with muriatic acid gas (the gaseous substance pro- cured from common salt by the action of sulphuric acid.) ‘he camphor procured in well conducted ex- periments amounts to half of the oil of turpentine used. tt agrees with common camphor in most of its sensible properties ; but differs materially in its chemical quali- ties and composition. It is not soluble without decom- position in nitric acid. From the experiments of Geh- len, it appears to consist of the elements of oil of tur- pentine, carbon, hydrogene and oxygene, united to the elements of muriatic gas, chlorine and hydrogene. From the analogy of artificial to natural campher, it does not appear improbable, that natural camphor may be a secondary vegetable compound, consisting of cam- phoric acid and volatile oil. Camphor is used medici- nally, but it has no other application. 15. Fived oil is obtained by expression from seeds and fruits; the olive, the almond, linseed and rape-seed. afford the most common vegetable fixed oils. The pro- perties of fixed oils are well known. Their specific gravity is less than that of water; that of olive and of ‘ape-seed oil is 913; that of linseed and almond oil 932; that of palm oil 968 ; that of walnut and beech mast oil bee! * ] mo my m 13 923, Many of the fixed oils congeal at a lower tempe-— rature than that at which water freezes. They all require for their evaporation a higher temperature than that at which water boils. ‘The products of the combustion of oil are water, and carbonic acid gas. From the experiments of Gay Lussac and Thenard, it appears that olive oil contains in 100 parts, Carbon - 4 717,213 Oxygene - - 9,427 Hydrogene - : 13,360 This estimation is a near aproximation to 11 propor- tions of carbon, 20 hydrogene, and one oxygene. The following is a list of fixed oils, and of the trees _ that afford them. Olive oil, from the Olive tree (Olea Europea,) Lin- seed oil, from the common and Perennial Flax (Linum usitatissimum et perenne,) Nut oil, from the Hazel nut (Coryllus avellana,) Walnut, (Juglans regia,) Hemp oil, from the Hemp (Cannabis sativa,) Almond oil from the sweet Almond, (Amygdalus communis,) Beech oil, from the common Beech (Fagus sylvatica,) Rape-seed. oil, from the Rapes (Brassica napus et campestris,) Pop- py oil, from the Poppy (Papaver somniferum,) oil of Sesamum, from the Sesamum (Sesamum orientale,) Cucumber oil, from the Gourds (Cucurbita pepo et ma- leppo,) oil of Mustard, from the Mustard (Sinapis ni- gra et arvensis,) oil of Sunflower, from the annual and perennial Sunflower, (Helianthus annuus et perennis,) Castor Oil, from the Palma Christi (Ricinus commu- nis,) 'Tobacco-seed oil, from the Tobacco (Nicotiana tabacum et rustica,) Plum kernel oil, from the Plum tree (Prunus domestica,) Grape-seed oil, from the Vine (Vitis vinifera,) Butter of cacoa, from the Cacoa tree ( Theobroma cacao,) Laurel oil, from the sweet Bay tree (Laurus nobilis.) The fixed oils are very nutritive substances; they are of great importance in their applications to the purposes of life. Fixed oil, in combination with soda, forms the finest kind of hard soap. ‘he fixed oils are used ex- teusively in the mechanical arts, and for the preparation of pigments and varnishes. 46. Volotile vil, likewise called essential oil, differs K carbon, hydrogene, and oxygene; but no accurate jex- : from fixed oil, in being capable of | evaporation by amuch lower degree of heat; in being soluble in alcohol, and _ in possessing a very slight degree of solubility in’wa- each species; the volatile oils inflame with more facility — than the fixed oils, and afford by their combustion dif- : ap ch ter. ine, There is a great number of volatile oils, distinguish- ed by their smell, their taste, their specific gravity, and other sensible qualities. A strong and peculiar odour may however be considered as the great characteristic of ferent proportions of the same substances, water, car- bonic acid, and carbon. | The following specific gravities of different volatile oils were ascertained by Dr. Lewis. Oil of Sassafras - - - 41094 Cinnamon - - - 4035 —— Cloves - - 1034 —— Fennel - - - 997 —— Dill - - - - 994 —— Penny Royal - - 978 : —- Cummin =the - oe OSes 4 —— Mint - : - : 975 —— Nutmegs - - - 948 : —— 'lansy - : - 946 i —— Carraway - - . 940 ee —— Origanum - - - 940 : —— Spike - : - ies 936 ; Rosemary — - : - 934 i —— Juniper - : > 914 ; —— Oranges - - : 888 : —— Turpentine - - = - > 792 . The peculiar odours of plants seem, in almost all ca- ses, to depend upon the peculiar volatile oils they con- tain. All the perfumed distilled waters owe their pe- 4 culiar properties to the volatile oils they hold in solu- tion. By collecting the aromatic oils, the fragrance of . flowers, so fugitive in the common course of nature, is as it were embodied and made permanent. ‘ It cannot be doubted that the volatile oils consist of — ae ‘19 periments have as yet been made on the proportions in which these elements are combined. The volatile oils have never been used as articles of food; many of them are employed in the arts, in the - manufacture of pigments and varnishes ; but their most extensive application is as perfumes. 17. Woody fibre is procured from the wood, bark, leaves, or flowers of trees, by exposing them to the re- peated action of boiling water and boiling alcohol. It is the insoluble matter that remains, and is the basis of the solid organized parts of plants. ‘There are as ma- ny varieties of woody fibre as there are plants and or- gans of plants; but they are all distinguished by their fibrous. texture, and their insolubility. Woody fibre burns with a yellow flame, and produces. water and carbonic acid in burning. When it is distil- led in close vessels, it yields a considerable risiduum of charcoal. Itis from woody fibre, indeed, that charcoal is procured for the purposes of life. The following table contains the results of experi- ments made by Mr. Mushet, on the quantity of charcoal afforded by different wood. 400 parts of Lignum Vite ~~ - 26,8 of charcoal _ Mahogany - 25,4 Laburnum - 24,5 — Chesnut - - 23,2 Oak - : - 22,6 American black Beech - : 21,4 Walnut - ; 20,6 Holly - = 19,9 Beech - - 19,9 —————— American Maple 19,9 ————— Elm. - : 19,5 Norway Pine - 19,2 — Sallow - - 18,4 ——--——. Ash - - 17,9 — Birch: - : 17,4 a Scottish Fir - , 16,4 M. Gay Lussac and Thenard haye concluded from ca 76 their experiments on the wood of the oak and the beech, that 1400 parts of the first contain : Of Carbon . 52,53 — Oxygene - 41,78 — Hydrogene 5,69 and 100 parts of the second : Of Carbon - 51,45 — Oxygene - 42, — Hydrogene 5,82 Supposing woody fibre to be a definite compound, these estimations lead to the conclusion, that it consists of five proportions of carbon, three of oxygene, and six of hydrogene ; or 57 carbon, 45 oxygene, and six hy- drogene. ~ It will be unnecessary to speak of the applications of woody fibre. The different uses of the woods, cotton, linen, the barks of trees are sufficiently known. Woody Bore. Bapecore to be an indigestible substance. . The acids found in ” the vegetable kingdom are numerous ; the true vegetable acids which axial ready formed in the j juices or organs of plants, are the oxalic, citric, tartaric, benzoic, acetic, malic, gallic, and prus- sic acid. All these acids, except the acetic, malic, and prussic acids, are white crystallized bodies. The acetic, malic, and prussic acids have been obtained only in the fluid state; they are all more or less soluble in water; all have a sour taste except the gallic and prussic acids ; of which the first has an astringent taste, and the latter a taste like that of bitter almonds. The oxalic acids exists, uncombined, in the liquor which exudes from the Chich pea (Cicer arietinum.) and may be procured from wood sorrel ( Owalis acetosel- la,) common sorrel, and other species of Rumex ; and from the Geranium acidum. Oxalic acid is easily dis- covered and distinguished from other acids by its pro- perty of decomposing all calcareous salts, and forming with lime a salt insoluble in water; and by its crystal- he lizing in four-sided prisms. V7 The citric acid is the peculiar acid existing in the juice of lemons and oranges. It may likwise be obtain- ed from the cranbery, whortleberry, and hip. Citric acid is distinguished by its forming a salt inso- - luble in water with lime; but decomposable by the mi- neral acids. The tartaric acid may be obtained from the juice of _ mulberries and grapes; and likewise from the pulp of the tamarind. It is characterised by its property of forming a difficultly soluble salt with potassa, and an insoluble salt decomposable by the mineral acids with lime. Benzoic acid may be procured from several resinous substances by distillation; from benzoin, storax, and balsam of olu. It is distinguished from the other acids by its aromatic odour, and by its extreme vola- tility. Malic acid may be obtained from the juice of apples, barberries, plums, elderberries, currants, strawberries, and raspberries. It forms a soluble salt with lime; and is easily distinguished by this test from the acids alrea- dy named. Acetic acid, or vinegar, may be obtained from the sap of different trees. It is distinguished from malic acid by its peculiar odour; and from the other vegeta- ble acids by forming soluble salts with the alkalies. and earths. Gallic acid may be obtained by gently and gradually heating powdered gall-nuts, and receiving the volatile matter in a cool vessel. A number of white crystals will appear, which are distinguished by their property of rendering solutions of iron, deep purple. The vegetable prussic acid is procured by distilling laurel leaves, or the kernels of the peach, and cherry, or bitter almonds. It is characterized by its property of forming a blueish green precipitate, when a little al- kali is added to it, and it is poured into solutions con- taining iron. It is very analogous in its properties to _ the prassic acid obtained from animal substances; or by passing ammonia over heated charcoal; but this last , * body forms, with the red oxide of iron, the deep, bright — blue substance, called Prussian, blue. Two other vegetable acids haye been found in the products of plants; the morolyxic acid in a saline exu-- dation from the white mulberry tree, and the kinic acid in a salt afforded by Peruvian bark; but these two bodies have as yet been discovered in no other cases. ~ The phosphoric acid is found free in the onion; and the ~ phosphoric, sulphuric, muriatic, and nitric acids, exist ~ in many saline compounds in the vegetable kingdom; — but they cannot with propriety be considered as vegata- ble products. Other acids are produced during the com- — bustion of vegetable compounds, or by the action of ni- — tric acid upon them; they are the camphoric acid, the mucous or saclactic acid, and the suberic acid; the first of which is procured from camphor ;' the second from — gum or mucilage; and the third from cork,by the action — of nitric acid. From the experiments that have been made upon the vegetable acids, it appears that all of them, except the — prussic acid, are constituted by different proportions of — carbon, hydr ogene, and oxygene ; the prussic acid con- sists of carbon, azote, and hydrogene, with a little oxy- gene. The gallic acid contains more carbon than any of the other vegetable acids. The following estimates of the composition of some of the vegetable acids have been made by Gay Lussac and Thenard. 4 400 parts of oxalic acid contain : Carbon - - 26,566 Hydrogene - 2,745 - Oxygene - - 70,689 Ditto of Tartaric acid: Carbon - - 24,050 Hydrogene - 6,629 Oxygene - - 69,324 Ditto citric acid: Carbon - - 33,814 Hydrogene - 6,330 Oxygene- - 59,859 Ditto acetic acid : st Carbon - - 50,224 Hydrogene - 5,629 Oxygene- - 44,147 79) . 400 parts: ot mucous or saclactic acid: Carbon - - 33,69 Hydrogene - - 3,62 Oxygene - - 62,69 ' These estimations agreemearly with the following de- finite proportions. In oxalic acid 7 proportions of car- bon, 8 of hydrogene, and 15 of oxygene ;* in citric acid, 8 carbon, 28 hydrogene, 18 oxygene; in acetic acid, 3 carbon, 6 hydrogene, 4 oxygene; in acetic acid,. 48 carbon, 22 hydrogene, 12 oxygene; in mucous acid, 6 corbon, 7 hydrogene, 8 oxygene. | The applications of the vegetable acids are well known. The acetic and citric acids are extensively used. The agreeable taste and wholesomeness of various ve- getable substances used as food, materially depend up- on the vegetable acid they contain. 49. Fixed alkali may be obtained in acqueous solu- _ tion from most plants by burning them, and treating the ashes with quick lime and water. The vegetable alkali, or potassa, is the common alkali in the vegetable king- dom. ‘This substance in its pure state is white, and semi-transparent, requiring a strong heat for its fusion, and possessed of a highly caustic taste. In the matter usually called pure potassa by chemists, it exists com- bined with water, and in that commonly called pearl ashes, or potashes in commerce, it is combined with a small quantity of carbonic acid. Potassa in its uncom- bined state, as has been mentioned, page 39, consists of the highly inflammable metal potassium, and oxygene, one proportion of each. Soda,. or the mineral alkali, is found in some plants that grow near the sea; and is obtained combined with water, or carbonic acid, in the same manner as potassa 5 and consists, as has been stated, page 39, of one pro- portion of sodium, and two proportions of oxygene. In its properties it is very similar to potassa: but may be easily distinguished from it by this character: it forms a hard soap with oil: potassa forms a soft soap. _ * According to Dr. Thomson’s experiments, oxalic acid consists of 3 proportions of carbon, 4 of oxygene, and 4 of hydrogene, a result very different indeed from that of the French chemists. BO es Waar ie : Pear] ashes, and barilla and kelp, or the impure soda obtained from the ashes of marine plants, are very va- _ luable in commerce, principally on account of their uses in the manufacture of glass and soap. Glass is © made from fixed alkali, flint, and certain metallic sub- — stances. a To know whether a vegetable yields alkali, it should — be burnt, and the ashes washed with a small quantity — of water. If the water, after being for some time ex- posed to the air, reddens paper tinged with turmeric ; or renders vegetable blues, green, it contains alkali. To ascertain the relative quantities of pot-ashes af- — forded by different plants, equal weights of them should — be burnt: the ashes washed in twice their volume of — water; the washings should be passed through blotting paper and evaporated to dryness: the relative weights — of the salt obtained will indicate very nearly the rela- — tive quantities of alkali they contain. The value of marine plants in producing soda, may — be estimated in the same manner, with sufficient correct- _ ness for all commercial purposes. Herbs, in general, furnish four or five times, and shrubs two or three times as much pot-ashes as trees. The leaves produce more than the branches, and the branches more than the trunk. Vegetables burnt in a green state produce more ashes than in a dry state. The following table* contains a statement of the quan- tity of pot-ashes afforded by some common trees and ~ plants. | 10,000 parts of Oak - - - 45 —_—_— of Elm- - - 39 —_—_-—_—— of Beech: - - 42 ——_——— of Vine - - 55 ————— of Poplar - - 7 —_——— of Thistle - - 53 ————— of Fern- - - 62 ——-——— of Cow Thistle 196 -————. of Wormwood 730 of Vetches - - 275 *Tt is founded upon the experiments of Kirwan, Vauquelin, and ~ Pertuis. r ol SL r shiv 10,000 paris of Beans - - 200 —— of Fumitory - 790 _. The earths found in plants are four: silica or the earth of filints, alumina or pure clay, lime, and magne- sia. They are procured by incineration. ‘The lime is usually combined with carbonic acid. This substance and silica are much more common in the vegetable king- dom than magnesia, and magnesia more common than alumina. The earths form a principal part of the mat-— ter insoluble in water, afforded by the ashes of plants. The silica is known by not being dissolved by acids ; the calcareous earth, unless the ashes have been very intensely ignited, dissolves with effervescence in muria- tic acid. Magnesia forms a soluble and crystallizable salt, and lime, a difficultly soluble one with sulphuric acid. Alumina is distinguished from the other earths, by being acted upon very slowly by acids ; and in form- ing salts very soluble in water, and difficult of crystalii- zation with them. The earths appear to be compounds of the peculiar metals mentioned page 40, and oxygene, one proportion of each. The earths afforded by plants, are applied to no uses of common life; and there are few cases in which the knowledge of their nature can be of importance, or af- ford interest to the farmer. The only metallic oxides found in plants are those of iron and manganesum : they are detected in the ashes of plants; but in very minute quantities only. When the ashes of plants are reddish brown, they abound in oxides of iron. When black or purple, in oxide of mangane- sum; when these colours are mixed, they contain both substances. The saline compounds contained in plants, or afford- ed by their incineration, are very various. ‘The sul- a - a \f i j uf _ phuric acid combined with potassa, or sulphate of po- tassa, is one of the most usual. Common salt is like- _ wise very often found im the ashes of plants; likewise _ phosphate of lime, which is insoluble in water, but solu- _ ble in muriatic acid. Compounds of the nitric, muria- tic, sulphuric, and phosphoric acids, with alkalies and ! Ly earths,» cist in thewayror taney ants, or a by ‘their evaporation and incineration. “ The salt _ tassa are distinguished from those of soda, by their ducing .a precipitate in solutions of platina: those _ lime are characterized by the cloudiness they occasio in solutions containing oxalic acid ; those of magnesi by being rendered cloudy by solutions of ammoni Sulphuric acid is detected in salts by the dense whi precipitate it forms in solutions of baryta. Muriatic acid by the cloudiness it communicates to solution of nitrat of silver; and when salts contain nitric acid, they produce scintillations by being thrown upon burn- ing coals. 7 As no applications have been made of any of the 4 neutral salts, or analogous compounds found in piaiitaa@ in a separate state, it will be useless to describe thems individually. The following tables are given from Th. de Saussure’s Researches on vegetation, and contain ‘results obtained by that philosopher. ‘They exhibit hea quantities of soluble salts, metallic oxides, and earths: 4 afforded by the ashes of different plants. — : a My ia. » 1 4 Sa SPOR a i i ) WIN ¥ 7 w. byhra(s > A 4 ty * tse ¥ t , vi ) 10 ELL fy > aN MY os A) "Se aoe nse AE 0 AN Sb Heth: ApH) , 4 wy NAMES OF PLANTS. Leaves of oak (quercus robur) May 10 ----- Ditto. Sept. 27 ------ ood of a young oak, May 10 --------- Bark of ditto -------- Entire wood of oak - - - - Alburnum of ditto - - - - Bark of ditto-------- Cortical layers of ditto - - Extract of wood of ditto - : Soil from wood of ditto - — | Conon or 11| Extract from ditto ---- 12| Leaves of the poplar (po- pulus nigra) May 26 - 13| Ditto, Sept.12 ------- 14} Wood of ditto, Sept. 12 - 15| Bark of ditto-----.--- 16} Leaves of hazel (corylus avellana) May 1 -- - - 17} Do. washed in cold water 18} Leaves of ditto, June 22 19| Ditto, Sept. 20 ---.--- 20} Wood of ditto, May 1 - - 21| Bark of ditto---.---- 22| Entire wood of mulberry, (morus nigra) Novem. 23| Alburnum of ditto ---- 24) Bark of ditto-------- 25 | Cortical layers of ditto - - 26 | Entire wood of hornbeam, (carpinus betulus,) Novy. 27| Alburnum of ditto - - - - 28| Bark of ditto-------- 29| Wood of horse chesnut, (esculus hyppocastanum) May10----------- 30 | Leaves of ditto, May 10 - 31] Leaves of ditto, July 23 - 32| Ditto, Sept. 27------- 33| Flowers of ditto, May 10 34,| Fruit of ditto, Oct. 5 - -- 35| Plants of peas (piswm sa- tivum, ) in flower - - - - $6| Plants of peas (fisum sa- tivum,) in flower, ripe 37} Plants of vetches, (vicia faba,) before flowering, May 23---------- 38 | Ditto in flower, June 23 - 39 | Ditto ripe, July 23 - - - - 40 | Ditto, seeds separated - - 41 |Seeds of ditto-----.- 42 | Ditto in flower, raised in distilled water ----- Constituents of 100 Parts of the Ashes. { Sac) iba | 25 2|3 -loPl] 3 = es IS il 2] 4 =| ag 3 Sa ° Siac?) eset s | a P| os = g e= 3 on oe SfPeols| 2) 2 | s3/ 3/2] 2 : | 4 60 2 60. 73 61 41 111 7 (36 |11,5 8 16,75}27 | 3,3 72 5,3 60 4. 23,3 |22 | 2,5 5 19,5 |44,1 | + é 14 |g9 {11,3 12 136 22 35 | 8 | 0,25 62 5,6 |54 0,25 7 13 89 88 67|Leaves of rhododendron Jferrugineum, raised on Jura, a limestone moun- tain, June 20 Leaves of rhododendron ferrugineum, raised on Breven, a granitic moun- tain, June 27----.--- Branches of ditto, June Spikes of ditto, June 27 - Leaves of tir (pinus abies) raised on Jura, June 20 72} Ditto, raised on Breven, June 27 73] Branches of pine, June 20 74) Whortleberry (vaccinium myriillus,) raised on Ju- ra, Aug. 29 75| Ditto, raised on Breven - 68 LAN! A) rug Nine Waa ONG sy Sia Wi Pa iy Vi / My ie Ahy fe : Constituents of 100 Parts of i ) the Ashes. © ¥))) ee Seen Lae a AIRE or ot ne Terie Leek el Bal |é- a a 5 so pg & a etl -iobl S| 8/8 2 x Sh pieh/ 2) 2/8) |e reloe]@le1e2leloly NAMES OF PLANTS. Je #/ s{8=])/ 2/5 15 | = | 2° 8 suis lem oe a hag = SelAlfell sp F ioe wes Hf oS] wm - 171 a LS Comt Te Ge o 3 a be i) ie iS) ren] nl 43) Solydago vulgaris, before flowering, May 1----|— | 92) — 5 110,75} 1,5 | 1,5 | 0,75}18,25 44|Ditto, just in flower, July 0 MARRS OH RO Se at aka fy | 59 | 1,5 | 1,5 | 075/21 45|Ditto, seeds ripe, Sept. 20} — | 50) — 12 {17,25} 355 |) 1,5 [18,75 4} Plants of turnsol (Aedian- ’ thus annuus,) a month before flowering, June A aE SR TS se 8 A — {147} — 67 {11,56} 1,5 | 0,12)16,67 47|Ditto in flower, July 23 - | 13 [137/87 6 12,5 | 1,5 | 0,12/18,78 48]Ditto, bearing ripe seeds, Sept. 20 --------- 25 | 931753 4 3,75) 0,5 |17,75 49} Wheat (¢riticum sativum) .] in flower ------.-- —-fy— 12,75} 0,25|32 0,5 {12,25 50] Ditto, seeds ripe - - - - - - —|j-— 15 0,25/54 1 418,75 §1/Ditto, a month before flowering --------- — | 79) — 11,5 | 0,25/12,5 | 0,25)15,5 §2] Ditto, in flower, June 14- | 16 | 54/699 10,75] 0,25/26 0,5 121,5 §3|Ditto, seeds ripe «---- | — | 33) — 11,75} 0,25/51 0,75|23 54|Straw of wheat - - - - - - — | 43) — 2 55|Seeds of ditto - ------ | — | 13} — 56| Bran - ----------+-- mm | 52) — 57| Plants of maize (zea mays) a month before flower- ing, June 23 - ----- - | — [122] — |i69 | 5,75} 0,25] 7,5 | 0,25]17,25 58] Ditto, in flower, July 23 - | — | 81] — {169 6 0,25] 7,5 | 0,25|17 59| Ditto, seeds ripe - - - - - - — | 46 60|Stalks of ditto ------- — | 84) — 172,45] 5 1 {18 0,5 | 3,05 61|Spikes of ditto - - = - - --|— | 16 62|Seeds of ditto ------- — | 10) — |62 136 ee 0,12} 0,88 635|Chaff of barley (hordeum wulgare)------- -- | — | 42) — jleo | 7,75/12,5 [57 | 0,5 | 2,25 64]Seeds of ditto ------- — | 18] — |29 92.5 — {55,5 | 0,25} 2,8 REG aie aie wie wionciaors — }22 1922 — |21 0,12 29,88 Ata ial | Bd veh 24 |— |60 | 0,25]14,75 69 70 71 30] — |/@6 |14 |43,25] 0,75] 3,25]15,63 25] — |\21,1 |16,75|16,75| 2 | 5,77/91,52 10 11,5 5,4, ll 22,48 24,5 39 0,5 29. | 1 29} — |16 |12,27143,5 | 2,5 | 1,6 24,13 29) — |i15 12 foo |t9 | 5,5 [19,5 15) — |'15 26] — |it7 [18 [42 | 0,5 | 3,12119,38] 2 {22 19,5 17,5 | 85 Besides the principles, the nature of which has been just discussed, others have been described by chemi sts as belonging to the vegetable kingdom: thus a substance, somewhat analogous to the muscular fibre of animals, has been detected by Vauquelin in the papaw; and a matter similar to animal gelatine by Braconnot in the mushroom; but in this place it would be improper to dwell upon peculiarities ; my object being to offer such general views of the constitution of vegetables as may be of use to the agriculturist. Some distinctions have been adopted by systematical authors which I have not entered into, because they do not appear to me essential to this inquiry. Dr. Thomson, in his elaborate and learned system of chemistry, has described six vegeta- ble substances, which he calls mucus, jelly, sarcocol, asparagin, inulin, and ulmin. He states that mucus ex- ists in its purest form in linseed; but Vauquelin has lately shewn, that the mucilage of linseed is, in its es- sential characters, analogous to gum; but that it is com- bined with a substance similar to animal mucus: vege- table jelly, Dr. Thomson himself considers as a modifi- cation of gum. It is probable, from the taste of sarco- col, that it is gum combined with a little sugar. Inulin is so analogous to starch, that it is probably. a variety of that principle: ulmin has been lately shewn by Mr. Smithson to be a compound of a peculiar extractive mat= ter and potasssa; and asparagin is probably a similar combination. If slight differences in chemical and phy- sical properties be considered as sufficient to establish a difference in the species of vegetable substances, the catalogue of them might be enlarged to almost any ex- tent. No two compounds procured from different vege- tables are precisely alike ; and there are even differences in the qualities of the same compound, according to the time in which it has been collected, and the manner in which it has been prepared: the great use of classifica- tion in science is to assist the memory; and it ought to be founded upon the similarity of properties which are distinct, characteristic and invariable. The analysis of any substance containing mixtures of the different vegetable principles, may be made in such a manner as is necessary for the views of the agricultu- rist with facility. A given quantity, say 200 grains, of the substance should be powdered, made into a paste or mass, with a small quantity of water, and kneaded in the hands, or rubbed in a mortar for some time under cold water ; if it contain much gluten, that principle will separate in a coherent mass. After this process, whe- ther it has afforded gluten or not, it should be kept in contact with half a pint of cold water for three or four hours, being occasionally rubbed or agitated : the solid matter should be separated from the fluid by means of blotting paper : the fluid should be gradually heated ; if any flakes appear, they are to be separated by the same means as the solid matter in the last process, i. e. by filtration. The fluid is then to be evaporated to dry- ness. ‘The matter obtained is to be examined by ap- plying moist paper, tinged with red cabbage juice, or violet juice to it; if the paper become red, it contains acid matter; if it become green, alkaline matter; and the nature of the acid or alkaline matter may be known by applying the tests described page 77, 78, 79. If the solid matter be sweet to the taste, it must be supposed to contain sugar; if bitterish, bitter principle, or extract; if astringent, tannin: and if it be nearly insipid, it must be principally gum or mucilage. ‘To separate gum or mucilage from the other principles, alcohol must be boil- ed upon the solid matter, which will dissolve the sugar and the extract, and leave the mucilage; the weight of which may be ascertained. To separate sugar and extract, the alcohol must be evaporated till crystals begin to fall down, which are su- gar; but they will generally be coloured by some ex- tract, and can only be purified by repeated solutions in alcohol. Extract may be separated from sugar by dis- _ solving the solid, obtained by evaporation from alcohol, in a small quantity of. water, and boiling it for a long while in contact with the air. The extract will gradu- ally fall down in the form of an insoluble powder, and — the sugar will remain in solution. : If tannin exist in the first solution made by cold wa- ter, its separation is easily effected by the process de- — scribed page 66. The solution of isinglass must be gradually added, to prevent the existence of an excess 87 of animal jelly in the solution, which might be mistaken for mucilage. When the vegetable substance, the subject of experi- ment, will afford no more principles to cold water, it must be exposed to boiling water. This will unite to starch if there be any, and may likewise take up more sugar, extract, and tannin, provided they be intimately combined with the other principles of the compound. The mode of separating starch is similar to that of se- parating mucilage. If after the action of hot water any thing remain, the action of boiling alcohol is then to be tried. This will dissolve resinous matter; the quantity of which may be known by evaporating the alcohol: The last agent that may be applied is ether, which dissolves elastic gum, though the application is scarce- ly ever necessary ; for if this principle be present, it may be easily detected by its peculiar qualities. If any fixed oil or wax exist in the vegetable substance, it will separate during the process of boiling in water, and may be collected. Any substance not acted upon by water, alcohol, or ether, must be regarded as woody fibre. If volatile oils exist in any vegetable substances, it is evident they may be procured, and their quantity ascer- tained, by distillation. When the quantity of fixed saline, alkaline, metallic, or earthy matter in any vegetable compound is to be as- certained, the compound must be decomposed by heat, by exposing it, if a fixed substance, in a crucible, toa long, cotitinned red heat; and if a volatile substance, by passing it through an ignited porcelain tabe. ‘The na- ture of the matter so produced, may be lear at by apply- _ ing the tests mentioned in page 81. The only analyses in which the agricultural chemist can often wish to occupy himself, are those of substan- ces containing principally starch, srs gluten, oils, mu- cilage, albumen, and tannin. The two following statements will afford an idea of the manner in which the results of experiments may be arranged. The first is a statement of the composition of ripe peas. deduced from experiments made by Einhof ; the second are of the products afforded by oak bark, deduced from experiments conducted by myself. Parts. 3840 parts of ripe peas afford, of starch . 1265 Fibrous matter analogous to starch, with the coats of} 840 the peas : - 3840 parts of a substance analogous to gluten 550 Mucilage - - - - 249 Saccharine matter - - 84 Albumen . - - 66 Volatile matter - - - 40 Earthy i dase ah a 11 Loss - - r 229 4000 parts of dry oak bark, from a small tree depri- ved of epidermis, contain, Of woody fibre - 7 - - 876 —tannin - - - - - 57 —extract - - - - - 34 — mucilage - - - sass, evaporation, probably a mixture of albumen and extract - — loss, partly saline matter - - 30 — matter rendered insoluble vue | ai To ascertain the primary elements of the different ve- getable principles, and the proportions in which they are combined, different methods of analysis have been adopted. The most simple are their decomposition by heat, or their formation into new products by combus- tion. When any vegetable principle is acted on by a strong red heat, its elements become newly arranged. Such of them as are volatile are expelled in the gaseous form ; — and are either condensed as fluids, or remain permanent- _lyelastic. The fixed remainder is either carbonaceous, earthy, saline, alkaline, or metallic matter. To make correct experiments on the decomposition of vegetable substances by heat, requires a complica ap- 89 paratus, much time and labour, and all the resources of the philosophical chemist: but such results as are useful to the agriculturist may be easily obtained. The apparatus necessary is a green glass retort, attached by cement to a receiver, connected with a tube passing un- der an inverted jar of known capacity, filled with wa- ter.* - 17,26} Ale - . - » 8,88 Red Champagne | 11,30 || Brandy - - - | 53,39 White Champagne] 12,80 |} Rum. - - - 53.68 Burgundy - - | 14,53 |) Hollands - - - | 51,60 Ditto - - -. | 11,95 a 97 The spirits distilled from different fermented liquors _ differ in their flavour: for peculiar odorous matter, or - yolatile oils, rise in most cases with the alcohol. "The spirit from malt usually has an empyreumatic taste like that of oil, formed by the distillation of vegetable sub- stances. ‘he best brandies seem to owe their flavour to a peculiar oily matter, formed probably by the action of the tartaric acid on alcohol; and rum derives its char- acteristic taste from a principle i in the sugar cane. All the common spirits may, I find, be deprived of their pe- culiar flavour by repeatedly digesting them with a mix- ture of well burnt charcoal and [quicktime ; they then af- ford pure alcohol by distillation. "The cogniac brandies, I find, contain vegetable prussic acid, and their flavour may be imitated by adding to a solution of alcohol in water of the same strength, a few drops of the ethereal _ oil of wine produced during the formation of ether,* and. a similar quantity of vegetable prussic acid procured from laurel leaves or any bitter kernels. . I have mentioned ether in the course of this Lecture; this substance is procured from alcohol by distilling a mixture of equal parts of alcohol and sulphuric acid. It is the lightest known liquid substance, being of a spe- cific gravity 632 at 60°. It is very volatile, and rises in vapour even by the heat of the body. It is highly in- flammable. In the formation of ether it is most proba- ble that carbon and the elements of water are separated — from the alcohol, and that ether differs from alcohol in containing less oxygene and carbon; but its composi- tion has not yet been accurately ascertained. Like al- ‘cohol it possesses intoxicating powers. A number of the changes taking place in the veaetas ble principles depend upon the separation of oxygene and hydrogene as water from the compound ; but there is one of very great importance, in which a new combi- nation of the elements of water is the principal opera- tion. This is in the manufacture of bread. When any kind of flour, which consists principally of starch, is * In the process of the distillation of alcohol! and Siiphiwne acid af- ‘ter the ether is procured; by a higher degree of heat, a yellow fluid ‘ is produced, which is the substance in question. It has a flagrant _ smell and an agreeable taste. } { i a made into a paste with Tater. and immediately and gra dually heated to about 440°, ‘it increases in weight, and — is found entirely altered in ity properties ; it has lost its — solubility in water, and its power of being converted — into sugar. In this state it is unleavened bread. . When the flour of corn or the starch of potatoes, mix- ed with boiled potatoes, is made into a paste with water, kept warm, and suffered to remain 30 or 40 hours, it ferments, carbonic acid gas is disengaged from it, and it becomes filled with globules of elastic fluid. In this state it is raised dough, and affords by baking, leavened _ bread; but this bread is sour and disagreeable to the taste ; and leavened bread for use is made by mixing a little dough, that has fermented, with new dough, and kneading them together, or by kneading the bread with a small quantity of yeast. In the formation of wheaten bread more than 2 of the elements of water combine with the flour; more water is consolidated in the formation of bread from barley, and still more in that from oats; but the gluten in wheat, be- ing in much larger quantity than in other grain, seems to form a combination with the starch and w ater, which renders wheaten bread more digestible than the other species of bread. The arrangement of many of the vegetable principles in the different parts of plants has been incidentally mentioned in this Lecture; but a more particular state-— ment is required to afford just views of the relation be- tween their organization and chemical constitution, which ~ is an object of great importance. ‘The tubes and hex- agonal cells in the vascular system of plants are compo- sed of w oody fibre; and when they are not filled with fluid matter they contain some of the solid materials — which formed a constituent part of the fluids belonging — to them. In the roots, trunk, and branches, the bark, albur- num, and heartwood, the leaves and flowers; the great — basis of the solid parts is woody fibre. It forms by far the greatest part of the heartwood and bark; there is — less in the alburnum, and still less in the leaves and ~ flowers. ‘The alburnum of the birch contains so much — sugar and mucilage, that it is sometimes used in the 99 4 4 Norih of Europe as a substitute for bread. ‘The leaves ( of the cabbage, broccoli, and seacale, contain much mu- cilage, a little saccharine matter, and a little albumen. From 1000 parts of the leaves of common cabbage I obtained 44 parts of mucilage, 24 of sugar, and 8 of al- buminous matter. In bulbous roots, and sometimes in common roots, a large quantity of starch, albumen, and mucilage, are | often found deposited in the vessels; and they are most abundant after the sap has ceased to flow ; and afford a nourishment for the early shoots made in spring. ‘The- potato is the bulb that contains the largest quantity of soluble matter in its cells and vessels; and it is of most importance in its application as food. Potatoés in ge-- neral afford from one-fifth to one-seventh their weight of dry starch. From 100 parts of the common kidney potato, Dr. Pearson obtained from 32 to 28 parts of meal, which contained from 23 to 20 of starch and mucilage : and 400 parts of the Apple potato in various experiments, afford me from 18 to 20 parts of pure starch. From five pounds of the variety of the potato called Captain hart, Mr. Skrimshire, jun. obtained 12 oz. of starch, from the same quantity of the Rough red potato 103 oz., from the Moulton white 113, from the Vorkshire Ieidney 103 oz. from Hundred eyes 9 0z., from Purple red 83, from Ox noble 81. he other soluble substances in the potato are albumen and mucilage. From the analysis of Einhoff it appears that 7680 parts of potatoes afford Of Starch - ’ - - - 1153 — Fibrous matter analogous to starch 540 — Albumen - - - = aay, — Mucilage in the state of a satura-2 gj ted solution - - ‘ —. 2112 _ So that a fourth part of the weight of the potato at least may be considered as nutritive matter. The turnip, carrot, and parsnip, afford principally saccharine, mucilaginous, and extractive matter. Lob-— tained from 4000 parts of common turnips seven parts +. of mucilage, 34 of saccharine matter, and nearly one he part of albumen. 1000 parts of carrots furnished 95 parts of sugar, three parts of mucilage, and one-half of extracts 1000 parts of parsnip afforded 90 parts of sac- charine matter, and nine parts of mucilage. ‘The Wal- cheran or white carrot, gave in 1000 parts, 98 parts of a sugar, two parts of mucilage, and one of extract. Fruits, in the organization of their soft parts, approach to the nature of bulbs. They contain a certain quanti- ty of nourishment laid up in their cells for the use of the embryon plant; mucilage, sugar, starch, are found — in many of them often combined with vegetable acids. Most of the fruit trees common in Britain have been na- turalized on account of the saccharine matter they con- tain, which, united to the vegetable acids and mucilage, renders them at once agreeable to the taste and nutri- tive. The value of fruits for the manufacture of fermented liquors may be judged of from the specific gravity of their expressed juices. The best cider and perry are made from those apples and pears that afford the densest juices; and a comparison between different fruits may be made with tolerable accuracy by plunging them together into— a saturated solution of salt, or a strong solution of sugar: those that sink deepest will afford the richest juice. Starch or coagulated mucilage forms the greatest part of the seeds and grains used for food ; and they are ge- nerally combined with gluten, oil, or albuminous mat- ter. In corn, with gluten, in peas and beans, with al- buminous matter; and in rape-seed, hemp-seed, linseed, and the kernels of most nuts with oils. I found 100 parts of good full grained wheat sown in autumn to afford Of starch = - - 77 — Gluten - - 49 400 parts of wheat sown in spring, Of starch - : 70 — Gluten - - 24 400 parts of Barbary wheat, Of starch” - - 74 — Gluten - - 23 400 parts of Sicilian wheat, Se See ee lee Se ee AY eR ee ee ee ae ee ee eee ee Of starch = - it 75 — Gluten - - 24 1 have examined different specimens of North Ameri- can wheat, all of them have contained rather more glu- ten than the British. In general the wheat of warm cli- mates abounds more in gluten, and in insoluble parts ; and it is of ‘greater specific gravity, harder, and more difficult to grind. The wheat of the south of Europe, in consequence of the larger quantity of gluten it contains, is peculiarly fit- ted for making macaroni, and other preparations of flow- er in which a glutinous quality is considered as an ex- ceHlence. In some experiments made on barley, I obtained from 400 parts of full and fair Norfolk barley, Of Starch - - - 79 — Gluten t - - 6 — Husk - - - 8 The remaining seven parts saccharine matter. The su- gar in barley is probably the chief cause why it is more proper for malting than any other species of grain. HKinhoff has published a minute analysis of barley meal, He found in 3840 parts, Of volatile matter = - . 360 — Albumen - - - 44 — Saccharine matter - 200 — Mucilage - - - 176 — Phosphate of lime, with some ‘albumen - - - 9 — Gluten - - - 135 — Husk, with some gluten and starch - - - 260 — Starch not quite free from STUER 35. = - - 2580 — Loss - - - - 78 Rye afforded to Einhoff, in 3840 parts; 2520 meal, 930 husk, and 390 moisture ; and the same quantity of meal analyzed gave, Of Starch - =. nae) eas — Albumen - - - 126 ‘ian oo — Mucilage - - - 436 a — Saccharine matter - 426 — Gluten not dried - 364 Remainder husk and loss. I obtained from 1000 parts of rye, grown in Suffolk, "4 641 parts of starch, and five parts of gluten. 100 parts of oats, from Sussex, afforded me 59 parts of starch, six of gluten and two of saccharine matter. 1000 parts of peas, grown in Norfolk, afforded me 501 parts of starch, 22 parts of saccharine matter, 35 parts of albuminous matter, and 16 parts of extract, which become insoluble during evaporation of the sac- charine fluid. From 3840 parts of marsh beans (Vicia faba,) Ein- hoff obtained, Of Starch - - - - 1312 — Albumen - - - - 31 — Other matters which may be } conceived nutritive; such as 1204 gummy, starchy, fibrous mat- es ter analogous to animal matter _ The same quantity of kidney beans (Phaseolus vul- _ garis,) afforded, Of matter analagous to starch - 1805. — Albumen and matter ap- proaching to animal mat- 851 ter in its nature - y — Mucilage - : 799 From 3840 parts of lentiles he obtained 1260 parts of starch, and 1433 of a matter analogous to animal mat- ter. The matter analogous to animal matter is described by Einhoff; as a glutinous substance insoluble in wa- ter; soluble in alcohol when dry, having the appearance of glue; probably a peculiar modification of gluten. ag ao : Le es | . q { 4 | | | 103 | From 16 parts of hemp-seeds Bucholz obtained three parts of oil, three and a half parts of albumen, about _ one and three quarters of saccharine and gummy matter. _ The insoluble husks and coats of the seeds weighed six .and one-eighth parts. The different parts of flowers contain different sub- stances: the pollen, or impregnating dust of the date, has been found by Fourcroy and Vauquelin to contain a matter analogous to gluten, and a soluble extract abounding in malic acid. Link found in the pollen of the hazel-tree, much tannin and gluten. Saccharine matter is found in the nectarium of flow- ers, or the receptacles within the corolla, and by tempt- ing the larger insects into the flowers, it renders the work of impregnation more secure; for the pollen is often by their means applied to the stigma; and this is particu- | larly the case when the male and female organs are in different flowers or different plants. It has been stated that the fragrance of flowers de- pends upon the volatile oils they contain ; and these oils, by their constant evaporation, surround the flower with a kind of odorous atmosphere; which, at the same time that it entices larger insects, may probably preserve the parts of fructification from the ravages of smaller ones. Volatile oils, or odorous substances, seem particularly destructive to these minute insects and animalcules which feed on the substance of vegetables; thousands . of aphides may be usually seen in the stalk and leaves of the rose but none of them are ever observed in the flower. Camphor is used to preserve the collections of naturalists. ‘The woods that contain aromatic oils are remarked for their indestructibility ; and for their ex- emption from the attacks of ‘insects : this is particularly _ the case with the cedar, rose-wood, and cypress. ‘The gates of Constantinople, which were made of this last wood, stood entire from the time of Constantine, their founder, to that of Pope Eugene LV. a period of 1100 ears. The petals of many flowers afford saccharine and - Inucilaginous matter. The white lily yields mucilage abundantly : and the orange lily a mixture of mucilage and sugar; the petals of the convolvulus afford sugar, mucilage, and albuminous matter. The chemical nature of the colouring matters of flow- ers has not as yet been subject to any very accurate ob- servation. ‘These colouring matters, in general, are very transient, particularly the blues and reds; alkalies change the colours of most flowers to green, and acids to red. An imitation of the colouring matter may be made by digesting solutions of gall-nuts with chalk: a green fluid is obtained, which becomes red by the ac- tion of an acid; and has its green colour restored by means of alkalies. ‘a - The yellow colouring matters of flowers are the most permanent; the carthamus contains a red anda yellow colouring matter; the yellow colouring matter is easily dissolved by water, and from the red, rouge is prepared by a process which is kept secret. The same substances as exist in the solid parts of plants are found in their fluids, with the exception of woody fibre. Fixed and volatile oils containing resin or camphor, or analogous substances ‘in solution exist in the cylindrical tubes belonging to a number of plants. Different species of Euphorbia emit a milky juice, which when exposed to air deposit ‘a substance analogous to starch, and another similar to gluten. Opium, gum elastic, gamboge, the poisons of the Upas Antiar and Tiute, and other substances that exude from | plants, may be considered as peculiar juices belonging to appropriate vessels. The sap of plants, in general, is very compound in its nature: and contains most saccharine, mucilaginous, © and albuminous matter in the alburnum; and most tan- nin and extract in the bark. ‘The cambium, which is the mucilaginous fluid found in trees between the wood and the bark, and which is essential to the formation of new parts, seems to be derived from these two kinds of sap; and probably is a combination of the mucilaginous and albuminous matter of one, with the astringent mat- ter of the other, in a state fitted to become organized by the separation of its watery parts. . The alburnous saps of some trees have been chemi- cally examined by Vauquelin. He found in those of the elm, beech, yoke elm, hornbeam and birch, extractive and mucilaginous matter, acetic acid combined with po-— tassa or lime. The solid matter afforded by their eya~ 405 poration yielded an ammoniacal smell, probably owing to albumen: the sap of the birch afforded saccharine matter. Deyeux in the sap of the vine and the yoke elm has’ detected a matter analogous to the curd of milk. 1 found a substance similar to albumen in the sap of the walnut tree. I found the juice which exudes from the vessels of the marshmallow when cut, to be a solution of mucilage. - The fluids contained in the sap vessels of wheat and barley, afforded in some experiments which I made on them, mucilage, sugar, and a matter which coagulated by heat; which last was most abundant in wheat. The following table contains a statement of the quan- tity of soluble or nutritive matters contained in varieties of the different substances that have been mentioned, and of some others which are used as articles of food, either for man or cattle. ‘The analyses are my own; and were conducted with a view to a knowledge of the general nature and quantity of the products, and not of their intimate chemical composition. The soluble mat- ters afforded by the grasses, except that from the fiorin in winter, were obtained by Mr. Sinclair, gardener to the Duke of Bedford, from given weights of the grasses cut when the seeds were ripe; they were sent to me by his Grace’s desire for chemical examination; and form part of the results of an important and extensive series of experiments on grasses, made by direction of the Duke, at Woburn Abbey, the full details of which I shall hereafter have the pleasure of stating. a ea een 106 . Table of the Quantities of soluble or nutritive Mat- a ters afforded by 1000 Parts of different vegetable Substances. a n ee B | € laone =26 2 o. e js eee CEO |] we S5 ® |lopanze Hays VSM shi. te i] 55.0 st 4 4 Ae rie Me een irs = Rs Se tal | Vegetables or vegeta} E22 ag ile Bo yo G ble Substance. ect =o Be =i a = aaa " gts | > Css E< g as aii ety | ery Lunt 8 ‘ ofS | Middlesex wheat, 765 eas 190 average crop - - Spring wheat - - - - - - 700 rr 240 Mildewed wheat of 1806 178 ae 32 Blighted wheat of 1804 520 ati Yes bs ‘ ' 119 i may be considered as siliceous; and it must be separa- ted and its weight ascertained, after washing and dry- ing in the usual manner. "The alumina and the oxide of iron and manganesum, if any exist, are all dissolved by the sulphuric acid 5 they may be separated by succinate of ammonia, added to excess ; which throws down the oxide of iron, and by soap lye, which will dissolve the alumina, but not the oxide of manganesum: the weights of the oxides as- certained after they have been heated to redness will de- note their quantities. Should any magnesia and lime have escaped solution in the muriatic acid, they will be found in the sulphuric acid: this, however, is rarely the case; but the process for detecting them, and ascertaining their quantities, is the same in both instances. The method of analysis by sulphuric acid, is suffi- ciently precise for all, usual experiments ; but if very great accuracy be an object, dry carbonate of potassa must be employed as the agent, and the residuum of the incineration (6) must be heated red for a half hour, with four times its weight of this substance, in a crucible of silver, or of well baked porcelain. ‘The mass obtained must be dissolved in muriatic acid, and the solution evaporated till it is nearly solid; distilled water must then be added, by which the oxide of iron and all the earths, except silica, will be dissolved in combination as muriates. ‘The silica, after the usual process of lixi- viation, must be heated red; the other substances may be separated in the same manner as from the muriate and sulphuric solutions. This process is the one usually employed by chemi- cal lire ale for the analysis of stones. - If any saline matter, or soluble vegetable or ani- dant matter is suspected in the soil, it will be found in the water of lixiviation used for separating the sand. This water must be evaporated to dryress in a pro- per dish, at a heat below its boiling point. If the solid matter obtained is of a brown colour and inflammable, it may be considered as partly vegetable extract. If its smell, when exposed to heat, be like that of burnt feathers, it contains animal or albutinons iN 420)" Vii | matter; if it be white, mk not destructible by heat, it may be considered as principally saline mat- ter; the nature of which may be known by the tests described page St. 9. Should sulphate or phosphate of lime be suspect- ed in the entire soil, the detection of them requires a particular process upon it. A given weight of it, for in- stance, four hundred grains, must be heated red for half an hour in a crucible, mixed with one-third of powder- ed charcoal. ‘The mixture must be boiled for a quarter of an hour, in a half pint of water, and the fluid col- lected through the filtre, and exposed for some days to the aimosphere in an open vessel. Lf any notable quan- tity of sulphate of lime (gypsum) existed in the soil, a white precipitate will gradually form in the fluid, and the weight of it will indicate the proportion. Phosphate of lime, if any exist, may be separated from the soil after the process for gypsum. Muriatic acid must be digested upon the soil, in quantity more than sufficient to saturate the soluble earths ; the solution must be evaporated, and water poured upon the solid matter. This fluid will dissolve the compounds of earths with the muriatic acid, and leave the phosphate of lime un- touched. It would not fall within the limits assigned to this Lecture, to detail any processes for the detect tion of sub- stances which may be accidentally mixed with the mat- ters of soils. Other earths and metallic oxides are now and then found in them, but in quantities too minute to bear any relation to fertility or barrenness, and the search for them would make the analysis much more complica- ted without rendering it more useful. 10. When the examination of a soil is completed, the produc ts should be numerically arranged, and their quantities added together, and if they nearly equal the original quantity of soil, the analysis may be consider- ed as accurate. It must, however, be noticed, that when phosphate or sulphate of lime are discovered by the in- dependent process just described, (9,) a correction must be made for the general process, by subtracting a sum ae to their weight from the quantity of carbonate of lime, obtained by precipitation from the muriatic acid. 421. Tn arranging the products, the form should be in the order of the experiments by which they were procured. Thus, I obtained from 400 grains of a good siliceous sandy soil from a hop garden near ‘Tunbridge, Kent, Grains. Of water of absorption - - - : 19 Of loose stones and gravel principally siliceous 53 Of undecompounded vegetable fibres - - 14. Of fine siliceous sand - - - - - 2A2 Of minutely divided matter separated by agitation and filtration, and consisting of Carbonate of lime - - - . . 19 Carbonate of magnesia - - 3 Matter destructible by “ge principally ve ve ope sta- ble - - 15 Silica - - - - - . - 24 Alumina ~ - - : . - - 13 Oxide of iron - - - - - - 5 Soluble matter, principally common salt and vege- table extract - - - - : 3 Gypsum : : . - - - : 2 Amount of all the products’ 379 Loss’ - - - . 21 The loss in this analysis is not more than usually oc- curs, and it depetids upon the impossibility of collect- ing the whole quantities of the different precipitates ; and upon the presence of more moisture than is account- ed for in the water of absorption, and which is lost in the different processes. When the experimenter is become ac quainted with the use of the different instruments, the properties of the reagents, and the relations between ‘the external and chemical qualities of soils, he will seldom find it neces- sary to perform, in any one case, all the processes that have been described. When his soil, for instance, con- tains no notable proportion of calcareous matter, the ac- _ tion of the muriatic acid (7) may be omitted. In exam- — ——— ining peat soils, he will principally have to attend to the operation by fire and air (8;) and in the analysis of — Q i s- 422), ea chalks and loams, he will often be able to omit the ex _ periment. by sulphuric acid (9.) In the first trials that are made by persons unacquaint- ed with chemisiry, they must not expect much precision of result. Many difficulties will be met with: but in overcoming them, the most useful kind of practical know- ledge will | be obtained ; and nothing is so instructive in experimental science, as the detection of mistakes. The correct analyst ought to be well grounded in general chemical information ; but perhaps there is no better mode of gaining it, than that of attempting original in- vestigations. in pursuing his experiments he will be continually obliged to learn the properties of the sub- stances he is employing or acting upon; and his theo- retical ideas will be more valuable in being connected with practical operations, and acquired for the purpose of discovery. | Plants being possessed of no locomotive powers, can grow only in places where they are supplied with food ; and the soil is necessary to their existence, both as af- fording them nourishment, and enabling them to fix them- selves in such a manner as to obey those mechanical laws by which their radicles are kept below the surface, and their leaves exposed to the free atmosphere. As the systems of roots, branches and leaves are very dif- ferent in different vegetables, so they flourish most in different soils, the plants that have bulbous roots require a looser and a lighter soil than such as have fibrous roots; and the plants possessing only short fibrous radi- cles demand a firmer soil than such as have tap roots, _ or extensive lateral roots. A good turnip soil from Holkham, Norfolk, afforded me eight parts out of nine silicious sand; and the fine- ly divided matter consisted Of Carbonate of lime - - 638 — Silica - - - - 45: — Alumina - - - 4 44 — Oxide of iron - - - 3 — Vegetable and saline matter 5 — Weoibture ah ae . 3 re 123 I found the soil taken from a field at Sheffield-place in Sussex, remarkable for producing flourishing oaks, to consist of six parts of sand, and one part of clay and finely divided matter. And one hundred parts of the entire soil submitted to analysis, produced - Parts. Silica - - - - 54 Alumina - - - - 28 Carbonate of lime - - 3 Oxide of iron - + - - 5 Decomposing vegetable matter 4 Moisture and loss - - 3 An excellent wheat soil from the neighbourhood of West Drayton, Middlesex, gavé three parts in five of silicious sand; and the finely divided matter consist- ed of Carbonate of lime - - - 28 Silica - - - - - 32 Alumina - - : : 29 Animal or vegetable matter ak i moisture - - - Of these soils the last was by far the most, and the first the least, coherent in texture. In all cases the con- stituent parts of the soil which give tenacity and cohe- rence are the finely divided matters; and they possess the power of giving those qualities in the highest degree when they contain much alumina. of the weight of the plant consumed. If they be considered as necessary to the vegetable, it is as giving hardness and firmness to its organization. Thus, it has been mentioned that wheat, oats, and ma- ny of the hollow grasses, have an epidermis principally | of siliceous earth; the use of which seems to be to 125 strengthen them, and defend them from the attacks of . of insects and parasitical plants, Many soils are popularly distinguished as cold; and the distinction, though at first view it may appear to be founded on prejudice, is really just. Some soils are much more heated by the rays of the sun, all other circumstances being equal, than others ; and soils brought to the same degree of heat cool in dif- ferent times, i. e. some cool much faster than others. This property has been very little attended to in a philosophical point of view ; yet it is of the highest im- portance in agriculture. In general, soils that consist principally of a stiff white clay are difficultly heated ; ‘and being usually very moist, they retain their heat on- ly for a short time. Chalks are similar in one respect, that they are difficultly heated ; but being drier they re- tain their heat longer, less being consumed in causing the evaporation of their moisture. A black soil, containing much soft vegetable matter, is most heated by the sun and air; and the coloured soils, and the soils containing much carbonaceous mat- ter, or ferruginous matter, exposed under equal circum- stances to sun, acquire a much higher temperature than pale-coloured soils. When soils are perfectly dry, those that most readi- ly become heated by the solar rays likewise cool most rapidly ; but I have ascertained by experiment, that the darkest coloured dry soil (that which contains abun- dance of animal or vegetable matter ; substances which most facilitate the diminution of temperature, ) when heat- ed to the same degree, provided it be within the common limits of the effect of solar heat, will cool more slowly than a wet pale soil, entirely composed of earthy matter. I found that a rich black mould, which contained near- ly 1 of vegetable matter, had its temperature increased in an hour from 65° to 88° by exposure to sunshine ; whilst a chalk soil was heated only to 69° under the same circumstances. But the mould removed into the shade, where the temperature was 62°, lost, in half an hour, 15°; whereas the chalk, under the same circum- stances, had lost only 4°. A brown fertile soil, and a cold barren clay were each » ey, R gi ‘\eapls Ye oe hay ‘ AP ste UA et : 1 Ani V 4! 126 my Ui ts ihe artificially heated to 88°, having been previously dried: they were then exposed in a temperature of 57°; in half % an hour the dark soil was-found to have lost 9° of heat; the clay had lost only 6°. An equal portion of the clay containing moisture, after being heated to 88°, was ex- posed in a temperature of 55°; in less than a quarter of an hour it was found to have gained the temperature of the room. The soils in all these experiments were pla- ced in small tin plate trays two inches square, and half an inch in depth; and the temperature ascertained by a delicate thermometer. Nothing can be more evident, than that the genial heat of the soil, particularly in spring, must be of the highest impor tance to the rising plant. And when the leaves are fully developed, the ground is shaded; and any injurious influence, which in the summer might be expected from too great a heat, entirely prevented : so that the temperature of the surface, when bare and exposed to the rays of the sun, affords at least one indi- cation of the degrees of its fertility; and the thermo- meter may be sometimes a useful instrument to the pur- chaser or improyer of lands. The moisture in the soil influences its temperature ; and the manner in which it is distributed through, or combined with, the earthy materials, is of great impor- tance in relation to the nutriment of the plant. If wa- ter is too strongly attracted by the earths, it will not be absorbed by the roots of the plants : if it is in too great quantity, or too loosely united to them, it tends to in- | jure or destroy the fibrous parts of the roots. ) There are two states in which water seems to exist y in the earths, and in animal and vegetable substances: in the first state it is united by chemical, in the other by cohesive, attraction. If pure solution of ammonia or potassa be poured into a solution of alum, alumina falls down combined with water: and the powder dried by exposure to air will afford more than half its weight of water by distilla- tion; in this instance the water is united by chemical -attraction. The moisture which wood, or muscular fibre, or gum, that have been heated to 212°, afford by distillation at a red heat, is likewise water, the elements hee 127 of which were united in the substance by chemical com- bination. When pipe-clay dried in the temperature of the at- mosphere is brought in contact with water, the fluid is rapidly absorbed ; this is owing to cohesive attraction. Soils in general, vegetable, and animal substances, that have been dried at a heat below that of boiling water, increase in weight by exposure to air, owing to their ab- sorbing water existing in the state of vapour in the air, in consequence of cohesive attraction. ; The water chemically combined amongst the elements of soils, unless in the case of the decomposition of ani- mal or vegetable substances, cannot be absorbed by the roots of plants; but that adhering to the parts of the soil is in constant use in vegetation. Indeed there are few mixtures of the earths found in soils, that contain any chemically combined water; water is expelled from the earths by most substances that combine with them. Thus, if a combination of lime and water be exposed to carbonic acid, the carbonic acid takes the place of water; and compounds of alumina and silica, or other compounds of the earths, do not chemically unite with water : and soils, as it has been stated, are formed either by earthy carbonate’, or compounds of the pure earths and metallic oxides. When saline substances exist in soils, they may be united to water both chemically and mechanically ; but they are always in too small a quantity to influence ma- terially the relations of the soil to water. The power of the soil to absorb water by cohesive attraction, depends in great measure upon the state of division of its parts; the more divided they are, the greater is their absorbent power. The different con- stituent parts of soils likewise appear to act, even by cohesive attraction, with different degrees of energy. Thus vegetable substances seem to be more absorbent than animal substances ; animal substances more so than compounds of alumina and silica; and compounds of alumina and silica more absorbent than carbonates of lime and magnesia: these differences may, however, possibly depend upon the differences in theirstate of di- vision, and upon the surface exposed. 128 The power of soils to absorb water from air, is much connected with fertility. When this power is great, the plant is supplied with moisture in dry seasons; and the effect of evaporation in the day is counteracted by the absorption of aqueous vapour from the atmosphere, by the interior parts of the soil during the day, and by both the exterior and interior during night. The stiff clays approaching to pipe-clays in their na- ture, which take up the greatest quantity of water when it is poured upon them in a fluid form, are not the soils which absorb most moisture from the atmosphere in dry weather. ‘They cake, and present only a small surface to the air; and the vegetation on them is generally burnt up almost as readily as on sands. The soils that are most efficient in supplying the plant with water by atmospheric absorption, are those in which there is a due mixture of sand, finely divided clay, and carbonate of lime, with some animal or vegetable mat- ter: and which are so loose and light as to be freely permeable to the atmosphere. With respect to this quality, carbonate of lime and animal and vegetable matter are of great use in soils; they give absorbent power to the soil without giving & likewise tenacity : sand, which also destroys tenacity, on the contrary, ' gives little absorbent power. I have compared the absorbent powers of many soils with respect to atmospheric moisture, and I have always found it greatest in the most fertile soils ; so that it af- fords one method of judging of the productiveness of land. 1000 parts of a celebrated soil from Ormiston, in Kast Lothian, which contained more than half its weight of finely divided matter, of which 14 parts were car- bonate of lime, and nine parts vegetable matter, when dried at 212°, gained in an hour by exposure to air sa- turated with moisture, at temperature 62°, 18 grains. 1000. parts of a very fertile soil from the banks of the river Parret, in Somersetshire, under the same circum- stances, gained 16 grains. 4000 parts of a ‘eattt from Mersea, 1 in Kssex, worth 45 shillings an acre, gained 43 grains. 429 4000 grains of a fine sand from Essex, worth 28 shil- lings an Pacre, gained 14 grains. 1000 of a coarse sand worth 45 shillings an acre, gained only eight grains. 1000 of the soil of Bagshot-heath gained only three grains. Water, and the decomposing animal and vegetable matter existing in the soil, constitute the true nourish- ment of plants ; ; and as the earthy parts of the soil are useful in retaining water, so as to supply it in the proper proportions to the roots of the vegetables, so they are likewise efficacious in producing the proper distribution of the animal or vegetable matter ; when equally mixed with it they prevent it from decomposing too rapidly 5 and by their means the soluble parts are supplied 1 in proper proportions. Besides this agency, which may be considered as me- chanical, there is another agency between soils and or- ganizable matters, which may be regarded as chemical, in its nature. The earths, and even the earthy carbo- nates, have a certain degree of chemical attraction for many of the principles of vegetable and animal substan- ces. ‘This is easily exemplified in the instance of alu- mina and oil; if an acid solution of alumina be mixed with a solution of soap, which consists of oily matter and potassa; the oil and the alumina will unite and form a white powder, which will sink to the bottom of the fluid. The extract from decomposing vegetable canis when boiled with pipe-clay or chalk, forms a combination by which the vegetable matter is rendered more difficult of decomposition and of solution. Pure silica and sili- -ceous sands have little action of this kind; and the soils which contain the most alumina and carbonate of lime are, these which act with the greatest chemical energy in pre- serving manures. Such soils merit the appellation which is commonly g ziven to them of rich soils; for the vegeta- ble nourishment is long preserved in them, unless taken up by the organs of plants. Siliceous sands, on the contrary, deserve the term hungry, which is commonly applied to them; for the vegetable and animal matters they contain not being attracted by the PArEnY, constitu- R 480° - eh parts of the soil, are more liable to be decomposed by the action of the atmosphere, or carried off from them by water. In most of the black and brown rich vegetable moulds, the earths seem to be in combination with a peculiar ex- tractive matter, afforded during the decomposition of ve- getables: this is slowly taken up, or attracted from the earths by water, and appears to constitute a prime cause of the fertility of the soil. The standard of fertility of soils for different plants must vary with the climate; and mast be ate influenced by the quantity of rain. ‘The power of soils to absorb moisture ought to be | much greater in warm or dry counties, than in cold and moist ones; and the quantity of clay, or vegetable or | animal matter they contain greater. Soils algo on de- : clivities ought to be more absorbent than in plains or in the bottom of vallies. ‘Their productiveness likewise is influenced by the nature of the subsoil or the stratum on which they rest. . When soils are immediately situated upon a bed of rock or stone, they are much sooner rendered dry by evaporation, than where the subsoil is of clay or marle; | and a prime cause of the great fertility of the land in the moist climate of Ireland, is the proximity of the rocky strata to the soil. A clayey subsoil will sometimes be of material advan- tage to a sandy soil; and in this case it will retain mois- ture in such a manner as to be capable of supplying that lost by the earth above, in consequence of evaporation, or the consumption of it by plants. A sandy, or gravelly subsoil, often corrects the im- pertections of too great a degree of absorbent power in the true soil. ‘In calcareous countries, where the surface is a spe- cies of marle, the soil is often found only a few inches above the limestone; and its fertility is not impaired by the proximity of the rock ; though in a less absorbent soil, this situation would occasion barrenness ; and the sandstone and limestone hills in Derbyshire and North Wales, may be easily distinguished at a distance im summer by the different. tints “of the vegetation. ‘The ws 7 OS ay eee ee ee er ae ee : 131. grass on the sandstone hills usually appears brown and burnt up; that on the limestone hills flourishing and green. In devoting the different parts of an estate to the ne- cessary crops, it is perfectly evident from what has been said, that no general principle can be laid down, except when all the circumstances of the nature, composition, and situation of the soil and subsoil are known. The methods of cultivation likewise must be differ- ent for different soils. ‘The same practice which will be excellent in one case may be destructive in ano- ther. Deep ploughing may be a very profitable practice in a rich thick soil; and in a fertile shallow soil, situated upon cold clay or sandy subsoil, it may be extremely prejudicial. In a moist climate where the quantity of rain that falls annually equals from 40 to 60 inches, as in Lanca- shire, Cornwall, and some parts of Lreland, a siliceous sandy soil is much more productive than in dry districts ; and in such situations, wheat.and beans will require a less coherent and absorbent soil than in drier situations 5 and plants having bulbous roots, will flourish in a soil containing as much as 14 parts out of 15 of sand. Even the exhausting powers of crops will be influen- ced by like circumstances. In cases where plants can- not absorb sufficient moisture, they must take up more manure. And in Ireland, Cornwall, and the western Highlands of Scotland, corn will exhaust less than in dry inland situations. Oats, particularly in dry climates, are impoverishing in a much higher degree than in moist ones. Soils appear to have been originally produced in con- sequence of the decomposition of rocks and strata. It often happens that soils are found in an unaltered state upon the rocks from which they were derived. It is easy to form an idea of the manner in which rocks are converted into soils, by referring to the instance of soft granite, or porcelain granite. ‘This substance consists of three ingredients, quartz, feldspar, and mica. The quartz is almost pure silicious earth, in a crystalline form. The feldspar and mica are yery compounded sub- stances: both contain silica, alumina, and oxide ofi iron; in the feldspar there is usually lime and potassa: in the: mica, lime and magnesia. Whena granitic rock of this kind has been rot ex- posed to the influence of air and water, the lime and the potassa contained in its constituent parts are acted upon by water or carbonic acid; and the oxide of iron, which is almost always in its least oxided state, tends to com- bine with more oxygene; the consequence is, that the feldspar decomposes, and likewise the mica; but the first the most rapidly. The feldspar, which is as it were the cement of the stone, forms a tine clay: the mica partial- ly decomposed mixes with it as sand; and the undecom- posed quartz appears as gravel, or sand of different de- grees of fineness. As soon as the smallest layer of earth i is formed on the surface of a rock, the seeds of lichens, mosses, and other imperfect vegetables which are constantly floating in the atmosphere, and which have made it their rest- ing place, begin to vegetate; their death, decomposition, and decay, afford a certain quantity of organizable mat- ter, which mixes with the earthy materials of the rock ; in this improved soil more perfect plants are capable of subsisting ; these in their turn absorb nourishment from water and the atmosphere; and after perishing, afford new materials to those already provided: the decomposi- tion of the rock still continues ; and at length by such slow and gradual processes, a soil is formed in which even forest trees can fix their roots, and which is fitted to re- ward the labours of the cultivator. In instances where successive generations of yegeta- bles have grown upon a soil, unless part of their pro- duce has been carried off by man, or consumed by ani- mals, the vegetable matter increases in such a propor- tion, that the soil approaches to a peat in its nature ; and if in a situation where it can receive water from a higher district, it becomes spongy, and permeated with that fluid, and is gradually rendered incapable of sup- porting the nobler classes of vegetables. Many peat-mosses seem to have been formed by the destruction of forests, in consequence of the imprudent — use of the hatchet by the early cultivators of the coun- — 133 4 ae in which Mey exist: when the trees are felled in the out-skirts of a wood, those in the interior exposed to the influence of the winds ; ; and having been accustomed to shelter, become unhealthy, and die in their new situa- tion; and their leaves and branches gradually decom- | posing, produce a stratum of vegetable matter. In ma- ny of the great bogs in Lreland and Scotland, the larger trees iat: are found 3 in the out-skirts of thea: bear the marks of having been felled. In the interior few en- tire trees are found ; and the cause is, probably, that they fell by gradual decay; and that the fermentation and decomposition of the vegetable matter was most ra- pid where it was in the greatest quantity. Lakes and pools of water are sometimes filled up by the accumulation of the remains of aquatic plants; and in this case a sort of spurious peat is formed. The fer- mentation in these cases, however, seems to be of a dif- ferent kind. Much more gaseous matter is evolved ; and the neighbourhood. of morasses in which aquatic ve- getables decompose, is usually aguish and unhealthy ; whilst that of the true peat, or peat formed on soils ori- ginally dry, is always salubrious. The earthy matter of peats is uniformly analogous to that of the stratum on which they repose; the plants which have formed them must have derived the earths that they contained from this stratum. ‘Thus in Wilt- shire and Berkshire, where the stratum below the peat is chalk, calcareous earth abounds in the ashes, and ve-. ry little alumina or silica. They likewise contain much oxide of iron and gypsum, both of which may be deri- ved from the decomposition of the pyrites, so abundant in chalk. Different specimens of peat that I have burnt from the granitic and schistose soils of different parts of these islands, have always given ashes principally siliceous and aluminous; and a specimen of peat from the coun- ty of Antrim, gave ashes which afforded very nearly the same constituents as the great basaltic stratum of the county. Poor and hungry soils, such as are produced frém the decomposition’ of granitic and sandstone rocks, remain very often for ages with only a thin covering of vegeta- 134 tion. Soils from the decomposition of limestone, chalks, and basalts, are often clothed by nature with the peren- nial grasses ; and afford, when ploughed up, a rich bed of vegetation for every species of cultivated plant. Rocks and strata from which soils have been derived, and those which compose the more interior solid parts | of the globe, are arranged in a certain order; and asit often happens that strata very different in their nature are associated together, and that the strata immediately beneath the soil contain materials which may be of use for improving it, a general view of the nature and posi- tion of rocks aud strata in nature, will not, I trust, be unacceptable to the scientific farmer. Rocks are generally divided by geologists into two grand divisions, distinguished by the names of primary , and secondary. The primary rocks are composed of pure crystalline matter, and contain no fragments of other rocks. | The secondary rocks, or strata, consist only partly of crystalline matter; contain fragments of other rocks or strata; often abound in the remains of vegetables and marine animals; and sometimes contain the remains of land animals. The primary rocks are generally arranged in large masses, or in layers vertical, or more or less inclined to the horizon. The secondary ska are usually disposed in strata or layers, parallel, or nearly parallel to the horizon. The number of primary rocks which are commonly observed in nature are eight. | First, granite, which as s has been mentioned, is compo- ; sed of quartz, feldspar, and mica; when these ‘bodies are arranged in regular layers in the ‘vock, it is called gneis. Second, micaceous schistus, which is composed of quartz and mica arranged in layers, which are usually curvilineal. E Third, sienite, which consists of the substance called hornblende and feldspar. a Fourth, serpentine, which is constituted by feldspar and a hody named resplendent hornblende; and their separate crystals are mg so small as to give the stone © ax ine PO 4 95 ~ Fifth, porphyry, which consists of crystals of feldspar embedded in the same material, but usually of a differ- ent colour. Sixth, granular marble, which consists entirely of crystals of carbonate of lime; and which, when its co- lour is white, and texture fine, is the substance used by statuaries. Seventh, chlorite schist, which consists of chlorite, a green oi gray substance somewhat analogous to mica and feldspar. Eight, guartzose rock, which is composed of quartz in a granular form sometimes united to small quantities of the crystalline elements, which have been mentioned as belonging to the other rocks. The secondary rocks are more numerous than the pri- mary; but twelve varieties include all that are usually, found in these islands. First, grawwacke, which consists of fragments of quartz, or chlorite schist, embedded in a cement, prin- cipally composed of feldspar. Second, siliceous sandstone, which is composed of fine quartz or sand, united by a siliceous cement. Third, limestone, consisting of carbonate of lime, more compact in its texture than in the granular mar- ble ; and often abounding in marine exuvia. Fourth, aluminous schist or shale, consisting of the decomposed materials of different rocks cemented by a small quantity of ferruginous or siliceous matter; and often containing the impressions of vegetables. _ Fifth, calcareous sandstone, which is calcareous sand, cemented by calcareous matter. Sixth, zron stone, formed of nearly the same mate- rials as aluminous schist, or shale; but containing a much larger quantity of oxide of iron. Seventh, basalt or whinstone, which consists of feld- spar and hornblende, with materials derived from the decomposition of the primary rocks; the crystals are generally so small as to give the rock a homogeneous’ appearance ; and it is often disposed in very regular - columns, having usually five or six sides. Kighth, bituminous or common coal. Ninth, gypsum; the substance so well known by that name, which si sulphate of lime; and ‘often contains sand. i Tenth, rock salt. Hy Eleventh, chalk, which usually abounds in remains of marine animals, and contains horizontal layers of flints. Twellth plum-pudding stone, consisting of pebbles cemented by a ferruginous or siliceous cement. To describe more particularly the constituent parts of the different rocks and strata will be unnecessary : at any time, indeed, details on this subject are useless, un- less the specimens are examined by thefeye; and a close inspection and comparison of the different species, will, in a short time, enable the most common observer to dis- tinguish them. The highest mountains in these islands, and indeed in the whole of the old continent, are constituted by granite; and this rock has likewise been found at the greatest depths to which the industry of man has as yet been able to penetrate ; micaceous schist is often found immediately upon granite; serpentine or marble upon micaceous schist: but the order in which the primary rocks are grouped together is various. Marble and serpentine are usually found uppermost; but granite, though it seems to form the foundation of the rocky strata of the globe, is yet sometimes discovered above micaceous schist. The secondary rocks are always incumbent on the primary; the lowest of them is usually grauwacke : upon this, limestone or sandstone is often found; coal generally occurs between sandstone or shale ; basalt of- ten exists above sandstone and limestone ; rock salt al- most always occurs associated with red sandstone and gypsum. Coal,’ basalt, sandstone and limestone, are often arranged in different alternate layers, of no con- siderable thickness, so as to form a great extent of coun- try. In a depth of less than 500 yards, 80 of these different alternate strata have been counted. ) The veins which afford metallic substances, are fis-— sures more or less vertical, filled with a material differ-_ ent from the rock in which they exist. This material is almost always crystalline; and usually consists of calcareous spar, fluor spar, quartz, or heavy spar either” “4 y f , : : 137 separate or together. ‘I'he metallic substances a¥e ge- nerally dispersed through, or confusedly mixed with these crystalline bodies. ‘The veins in hard granite sel- dom afford much useful metal; but in the veins in soft granite, and in gneis, tin, copper, and lead are found. Copper and iron are the only metals usually found in the veins in serpentine. Micaceous schist, sienite, and granular‘marble, are seldom metalliferous rocks. Lead, tin, copper, iron, and many other metals are found in the veins in chlorite schist. _Grauwacke, when it con- tains few fragments and exists in large masses, is often a metalliferous rock. The precious metals, likewise iron, lead, and antimony, are found in it; and sometimes it contains veins or masses of stone coal, or coal free from bitumen. Limestone is the great metalliferous rock of the secondary family; and lead and copper are the metals most usually found in it. No metallic veins have ever been found in shale, chalk or calcareous sand- stone; and they are very rare in basalt and silicious sandstone.* In cases where veins in rocks are exposed to the at- mosphere, indications of the metals they contain may be often gained from their superficial appearance. When- ever fluor’ spar is found in a vein, there is always strong reason to suspect that it is associated with metallic sub- stances. A brown powder at the surface of a vein al- ways indicates-iron, and often tin; a pale yellow pow- der lead ; and a green colour in a vein denotes the pre- sence of copper. It may not be improper to give a general description of the geological constitution of Great Britain and Ivre- land. Granite forms the great ridge of hills extending from Land’s End through Dartmoor into Devonshire. The highest rocky strata in Somersetshire are grau- wacke and limestone. ‘The Malvern hills are compo- — sed of granite sienate and porphyry. The highest moun- tains in Wales are chlorite schist, or grauwacke. Gra- nite occurs at Mount Sorrel in Leicestershire. The great range of the mountains in Cumberland and West- * Tig. 16, will give a general idea of the appearance and arrange- ment of rocks and veins. s Lo Bo ih cL VS MY Ae, ‘ : ‘ We * ¥ DL 138° woreland, are porphyry, chlorite, schist, and grauwackes but granite is found at the western boundary. Through- out Scotland the most elevated rocks are granite, sienite, and micaceous schistus. No true secondary formations are found in South Britain, west of Dartmoor; and no basalt south of the Severn. The chalk district extends from the western part of Dorsetshire, to the eastern coast of Norfolk. The coal formations abound in the district between Glamorganshire and Derbyshire; and likewise in the secondary strata of Yorkshire, Durham, West- moreland, and Northumberland.* Serpentine is found only in three places in Great Britain; near Cape Li- zard in Cornwall, Portsoy in Aberdeenshire, and in Ayrshire. Black and gray granular marble is found near Padstow in Cornwall; and other coloured prima- ry marbles exist in the neighbourhood of Plymouth. Coloured primary marbles are abundant in Scotland ; and white granular marble is found in the Isle of Sky, in Assynt, and on the banks of Loch Shin in Suther- land: the principal coal formations in Scotland, are in Dumbartonshire, Ayrshire, Fifeshire, and on the banks of the Brora in Sutherland. Secondary limestone and sandstone are found in most of the low countries north of the Mendip hills. In Ireland there are five great associations of prima- ry mountains ; the mountains of Morne in the county of Down; the mountains of Donegal; those of Mayo and Galway, those of Wicklow, and those of Kerry. The rocks composing the four first of these mountain chains are principally granite, gneis, sienite, micaceous schist, and porphyry. The mountains of Kerry are chiefly constituted by granular quartz, and chlorite schist. Co- loured marble is found near Killarney; and white mar- ble on the western coast of Donegal. Limestone and Sandstone are the common secondary rocks found south of Dublin. In Sligo, Roscommon, and Leitrim, limestone, sandstone, shale, iron stone, and bituminous coal are found. The secondary hills in these counties are of considerable elevation ; and many of them have basaltic summits. ‘The northern coast of Ireland is principally basalt; this rock commonly reposes upon — a white limestone, containing layers of flint, and the same fossils as chalk ; but it is considerably harder than \) 4! 4139 that rock. There are some instances, in this district, ~ in which columnar basalt is found above sandstone and ~ shale, alternating with coal. ‘The stone coal of Ireland is principally found in Kilkenny, associated with lime- stone and grauwacke. It is evident from what has been said concerning the production of soils from rocks, that there must be at least as many varieties of soils as there are species of rocks exposed at the surface of the earth; in fact there are many more. Independent of the changes produced by cultivation and the exertions of human labour, the ma- terials of strata have been mixed together and transport- ed from place to place by various ‘great alterations that have taken place in the system of our globe, and by the constant operation of water. To attempt to clas8 soils with scientificaccuracy would « be a vain labour; the distinctions adopted by farmers are sufficient for the purposes of agriculture ; particularly if some degree of precision be adopted in the application of terms. The term sandy, for instance, should never be applied to any soil that does not contain at least se- ven-eighths of sand; sandy soils that effervesce with acids should be distinguished by the name of calcareous — sandy soil, to distinguish them from those that are sili- ceous. The term clayey soil should not be applied to any land which contains less than one-sixth of impalpa- ble earthy matter, not considerably effervescing with acids; the word loam should be limited to soils, contain- ing at least one-third of impalpable earthy matter, copi- ously effervescing with acids. A soil to be considered as peaty, ought to contain at least one-half of vegetable matter. In cases where the earthy part of a soil evidently con- sists of the decomposed matter of one particular rock, a name derived from the rock may with propriety be ap- plied to it. Thus, if a fine red earth be found imme- diately above decomposing basalt, it may be denomina- ted basaltic soil. If fragments of quartz and mica be found abundant in the materials of the soil, which is often the case, it may be denominated granitic soil; and the same principles may be applied to other like in- stances. In general, the soils, the materials of which are the Ne 440 most various and heterogeneous, are those called alluyi- al, or which have been formed from the depositions of » rivers ; many of them are extremely fertile. I have ex- amined some productive alluvial soils, which have been very different in their composition. The soil which has been mentioned page 128, as very productive, from the banks of the river Parret in Somersetshire, afforded me eight parts of finely divided earthy matter, and one part of siliceous sand; and an analysis of the finely divided matter gave the following results. 360 parts of carbonate of lime. 25 — alumina. 20) silica. 8 ——— oxide of iron. «* : 149 --—-—. vegetable, animal, and saline mat- ter. "A rich soil from the neighbourhood of the Avon in the valley of Evesham in Worcestershire, afforded me three- fifths of fine sand, and two-fifths of impalpable matter 5 the impalpable matter consisted of 35 Alumina. 41 Silica. 44 Carbonate of lime. 3 Oxide of iron. 7 Vegetable, animal, and saline matter. A specimen of good soil from 'Tiviot-dale, afforded five-sixths of fine siliceous sand, and one-sixth of im- palpable matter which consisted of 4{ Alumina. 42 Silica. 4 Carbonate of lime. 5 Oxide of iron. 8 Vegetable, animal, and saline matter. A soil yielding excellent pasture from the valley of the Avon, near Salisbury, afforded one-eleventh of coarse siliceous sand; and the finely divided matter consisted of a AS == ~ 2 eee Se ee : 44h 7 Alumina. 44 Silica. 63 Carbonate of lime. 2 Oxide of iron. . 44 Vegetable, animal, and saline matter. In all these instances the fertility seems to depend upon the state of division, and mixture of the earthy materials and the vegetable and animal matter; and may be easily explained on the principles which 1 have endeavoured to elucidate in the preceding part of this Lecture. In ascertaining the composition of sterile soils with a .yiew to their improvement, any particular ingredient which is the cause of their unproductiveness, should be particularly attended to; if possible, they should’ be compared with fertile soils in the same neighbourhood, and in similar situations, as the difference of the com- position may, in many cases, indicate the most proper methods of improvement. If on washa sterile soil it is found to contain the salts of iron, or any acid matter, it may be ameliorated by the application of quick lime. A soil of good apparent texture from Lincolnshire, was put into my hands by Sir Joseph Banks as remarkable for sterility: on examining it, I found that it contained sulphate of iron; and I offer- ed the obvious remedy of top dressing with lime, which converts the sulphate into a manure. If there be an excess of calcareous matter in the soil, it may be im- proved by the application of sand, or clay. Soils too abundant in sand are benefited by the use of clay, or marle, or vegetable matter. A field belonging to Sir Robert Vaughan at Nannau, Merionethshire, the soil of which was a light sand, was much burnt up in the sum- mer of 1805; I recommended to that gentleman the ap- plication of peat as a top dressirig. The experiment was attended with immediate good effects ; and Sir Ro- bert last year informed me, that the benefit was perma- nent. A deficiency of vegetable or animal matter must be supplied by manure. An excess of vegetable mat- ter is to be removed by burning, or to be remedied by the application of earthy materials. The improvement 442 ol peais, or bogs, or marsh lands, must be preceded by draining ; stagnant water being injurious to all the nu- tritive classes of plants. Soft black peats, when drain- ed, are often made productive by the mere application of sand or clay as a top dressing. When peats are acid, or contain ferruginous salts, calcareous matter is absolutuely necessary in bringing them into cultivation. When they abound in the branches and roots of trees, or when their surface entirely consists of living vegeta- bles, the wood or the vegetables must either be carried off, or be destroyed by burning. In the last case their ashes afford earthy ingredients, fitted to improve the tex- ture of the peat. The best natural soils are those of wbich the materi- als have been derived from different strata ; which have been minutely divided by air and water, and are inti- mately blended together : and in improving soils artifi- cially, the farmer cannot do better than imitate the pro- cesses of nature. The materials necessary for the purpose are seldom far distant: coarse sand is often found immediately on chalk; and beds of sand and gravel are common below clay. The labour of improving the texture or constitu- tion of the soil, is repaid by a great permanent advan- tage ; less manure is required, and its fertility insured : and capital laid out in this way secures for ever, the pro- ductiveness, and consequently the value of the land. LECTURE V. » On the Nature and Constitution of the Atmosphere ; and its Influence on Vegetables. Of the Germination of Seeds. Of the Functions of Plants in their differ- ent Stages of Growth ; with a general View of the Progress of Vegetation. Tue constitution of the atmosphere has been already generally referred to in the preceding Lectures. Water, carbonic acid gas, oxygene, and azote, have been men- tioned as the principal substances composing it; but more minute inquiries respecting their nature and agencies are, necessary to afford correct views of the uses of the at- mosphere in vegetation. On these inquiries I now propose to enter; the pur- suit of them, I hope, will offer some objects of practical use in farming; and present some philosophical illustra- tions of the manner in which plants are nourished; their organs unfolded, and their functions developed. If some of the salt called muriate of lime that has been just heated red be exposed to the air, even in the driest and coldest weather, it will increase in weight and become moist; and in a certain time will be con- verted into a fluid. If put into a retort and heated, it will yield pure water; will gradually recover its pris- tine state ; and, if heated red, its former weight : so that it is evident, that the water united to it was derived from the air. And that it existed in the air in an invisible and elastic form, is proved by the circumstance, that if a given quantity of air be exposed to the salt, its volume and weight will diminish, provided the experiment be correctly made. The quantity of water which exists in air, as vapour, varies with the temperature. In proportion as the wea- ther is hotter, the quantity is greater. At 50° of Fah- renheit air contains about one fiftieth of its volume of vapour; and as the specific gravity of vapour is to that i \ pete bi 144 of air ae as 40 to 45, this is about one- seventy- -fifth of its weight. At 100°, supposing that there is a free commuhica- tion with water, it contains about one fourteenth parts in volume, or one-twenty-first in weight. It is the con- densation of vapour by diminution of the temperature of the atmosphere, which is probably the principal cause of the formation of clouds, and of the deposition of dew, mist, snow, or hail. ' The power of different substances to absorb aqueous vapour from the atmosphere by cohesive attraction was discussed in the last Lecture. The leaves of living plants appear to act upon the vapour likewise in its elas- tic form, and to absorb it. Some vegetables increase in weight from this cause, when suspended in the atmos- phere and unconnected with the soil ; such are the house- leek, and different species of the aloe. In very intense heats, and when the soil is dry, the life of plants seems to be preserved by the absorbent power of their leaves : and it is a beautiful circum$tance in the economy of na- ture, that aqueous vapour is most abundant in the at- mosphere when it is most needed for the purposes of life ; and that when other sources of its supply are cut off, this is most copious. The compound nature of water has been referred to. It may be proper to mention the experimental proofs of its decomposition into, and composition from, oxygene and hydrogene. If the metal called potassium be exposed in a glass tube to a small quantity of water, it will act upon it with great violence; elastic fluid will be disengaged, which will be found to be hydrogene ; and the same ef- fects will be produced upon the potassium, as if it had absorbed a small quantity of oxygene ; and the hydro- gene disengaged, and the oxygene added to the potas- sium are in r weight as two to 15; and if two in volume of hydrogene, and one in volume of oxygene, which have the weights of two and 45, be introduced into a close vessel, and an electrical spark passed through them, they will inflame and condense into 47 parts of pure water. It is evident from the statements given in the third 145 Lecture, that water forms by far the greatest part of the sap of plants; and that this substance, or its elements, enters largely into the constitution of their organs and solid productions. Water is absolutely necessary to the economy of ve- getation in its elastic and fluid state; and it is not de- void of use even in its solid form. Snow and ice are ‘bad. conductors of heat; and when the ground is cover- ed with snow, or the surface of the soil or of water is frozen, the roots or bulbs of the plants beneath are pro- tected by the congealed water from the influence of the atmosphere, the temperature of which in northern win- ters is usually very much below the freezing point ; and this water becomes the first nourishment of the plant in early spring. ‘The expansion of water during its con-. gelation, at which time its volume increases one-twelfth, and its contraction of bulk during a thaw, tend to pul- verise the soil; to separate its parts from each other, and to made it more permeable to the influence of the air. If a solution of lime in water be exposed to the air, a pellicle will speedily form upon it, and a solid matter will gradually fall to the bottom of the water, and in a certain time the water will become tasteless ; this is ow- ing to the combination of the lime, which was dissol- ved in the water, with carbonic acid gas which existed in the atmosphere, as may be proved by collecting the film and the solid matter, and igniting them strongly in a little tube of platina or iron; they will give off car- bonic acid gas, and will become quicklime, which add- ed to the same water, will again bring it to the state of lime water. Vhe quantity of carbonic acid gas in the atmosphere is very small. It is not easy to determine it with pre- cision, and it must differ in different situations ; but where there is a free circulation of air, it is probably never more than one-five hundredth, nor less than one- eight hundredth of the volume of air. Carbonic acid gas is nearly one-third heavier than the other elastic parts of the atmosphere in their mixed state: hence at first view it might be supposed that it would be most abundant in the lower regions of the atmosphere ; but unless it has been immediately produced at the surface be i 14 ana of the earth in some chemical process, this ieee not if seem to be the case: elastic fluids of different specific sravities. have a tendency to equable mixture by a Spe- cies of attraction, and the different parts of the atmos- phere are constantly agitated and blended together by winds or other causes. De Saussure found lime water precipitated on Mount Blanc, the highest point of land in Europe; and carbonic acid gas has been ‘always found, apparently in due proportion, in the air brought down from great heights in the atmosphere by aerostatic adventurers. The experimental proofs of the composition of car- bonic acid gas are very simple. If 43 grains of well burnt charcoal be inflamed by a burning-glass in 100 cubical inches of oxygene gas, the charcoal will entirely disappear: and provided the experiment be correctly made, all the oxygene except a few cubical inches, will be found converted into carbonic acid ; and what is very remarkable, the volume of the gas is mk changed. On this last circumstance it is easy to found a correct esti- mation of the quantity of pure charcoal and oxygene in carbonic acid gas: the weight of 100 cubical inches is to that of 100 cubical inches of oxygene gas, as 47 to 34: so that 47 parts in weight of carbonic acid gas, must be composed of 34 parts of oxygeue and, 13 of charcoal, which correspond with the numbers given in the second Lecture. Carbonic acid is easily decomposed by heating potas- sium in it; the metal combines with the oxygene, and the charcoal is deposited in the form of a black powder. The principal consumption of the carbonic acid in the atmosphere, seems to be in affording nourishment to plants ; and some of them appear to be supplied with carbon chiefly from this source. Carbonic acid gas is formed during fermentation, com- bustion, putrefaction, respiration, and a number of ope- rations taking place upon the surface of the earth; and there is no other process known in nature by which it can be destroyed but by vegetation. After a given portion of air has been deprived of aqueous vapour and carbonic acid gas, it appears little altered in its properties; it supports combustion and, ani- * | f Hye) AAT mal life. ‘There are many modes of separating its prin- cipal constituents, oxygene and azote, from each other, A simple one is by burning phosphorus in a confined volume of air: this absorbs the oxygene and leaves the azote; and 100 parts in volume of air, in which phos- phorus has been burnt, yield 79 parts of azote: and by mixing this azote with 21 parts of fresh oxygene gas artificially procured, a substance having the original characters of air is produced. ‘lo procure pure oxy- gene from air, quicksilver may be kept heated in it, at about 600°, till it becomes a red powder; this powder, when ignited, will be restored to the state of quicksilver by giving off oxygene. Oxygene is necessary to some functions of vegeta- bles ; but its great importance in nature is in its relation to the economy of animals. It is absolutely necessary to their life. Atmospheric air taken into the lungs of animals, or passed in solution in water through the gills of fishes, loses oxygene; and for the oxygene lost, about an equal volume of carbonic acid appears. The effects of azote in vegetation are not distinctly known. As it is found in some of the products of ve- getation, it may be absorbed by certain plants from the atmosphere. It prevents the action of oxygene from being too energetic, and serves as a medium in which the more essential parts of the air act; nor is this cir- cumstance unconformable to the analogy of nature; for the elements most abundant on the solid surface of the globe, are not those which are the most essential to the existence of the living beings belonging to it. The action of the atmosphere on plants differs at dif-_ ferent periods of their growth, and varies with the va- rious stages of the development and decay of their or- gans ; some general idea of its influence may have been gained from circumstances already mentioned ; I shall now refer to it more particularly, and endeavour to connect it with a general view of the progress of vege- tation. . : If a healthy seed be moistened and exposed to air at a temperature not below 45°, it soon germinates; it shoots forth a plume which rises upwards, and a radi- cle which descends. ) 148 Tf the air be confined, it is found that in the process of. germination the oxygene, or a part of it is absorbed. The azote remains unaltered; no carbonic acid is ta- ken away from the air, on the ‘contrary some is added. x Seeds are incapable of germinating, except when oxy- . gene is present. In the exhausted receiver of the air- pump, in pure azote, in pure carbonic acid, when mois- tened they swell, but do not vegetate : and if kept in these gases, lose their living powers and undergo putre- faction. If a seed be examined before germination, it will be found more or less insipid, at least not sweet; but af- ter germination it is always sweet. Its coagulated mu- cilage, or starch, is converted into sugar in the process 5 a substance difficult of solution is changed into one easily soluble : and the sugar carried through the cells or ves- sels of the cotyledons, is the nourishment of the infant plant. It is easy to understand the nature of the change, by referring to the facts mentioned in the third Lecture ; and the production of carbonic acid renders probable the idea, that the principal chemical difference between sugar and mucilage depends upon a slight difference in the proportions of their carbon. The absorption of oxygene by the seed in germina- tion, has. been compared to its absorption in producing the evolution of fetal life in the egg: but this analogy is only remote. All animals, from the most to the least perfect classes, require a supply of oxygene.* From * The impregnated eggs of insects, and even fishes. do not pro- duce young ones, unless they are supplied with air, that is, unless the foetus can respire. I have found that the eggs of moths did not produce larve when confined in pure carbonic acid ; and when they were exposed in common air, the oxygene partly disappeared, and » carbonic acid was formed. The fish in the egg or spawn, gains its oxygene from the air dissolved in water; and those fishes that spawn in spring and summer in still water, such as the pike, carp, perch, and bream, deposit their eggs upon subaquatic vegetables, the leaves of which, in performing their healthy functions, supply oxygene to the water. The fish that spawn in winter, such as the salmon and trout, seek spots where there is a constant supply of fresh water, as near the sources of streams as possible, and in the most rapid cur- rents, where all stagnation is prevented, and where the water is satu- rated with air,to which it has been exposed during its deposition from clouds. It is the instinct leading these fish to seck a supply of Giim \ Ul eS ee ae CL (oe iA sha a hs ‘ 149 ‘the moment the heart begins to pulsaie till it ceases to beat, the aeration of the blood is constant, and the func- tion of respiration invariable ; carbonic acid is given off in the process, but the chemical change produced in the blood is unknown; nor is the reany reason to suppose the formation of any substance similar to sugar. In the, production of a plant from a seed, some reservoir of nourishment is needed before the root can supply sap: and this reservoir is the cotyledon in which it is stored up in an insoluble form, and protected if necessary du- ring the winter, and rendered soluble by agents which are constantly present on the surface. ‘The change of starch into sugar, connected with the absorption of oxy- gene, may be rather compared to a process of fermenta- tion than to that of respiration; it is a change effected upon unorganized matter, and can be artificially imita- ted ; and in most of the chemical changes that occur when vegetable compounds are exposed to air, oxygene is absorbed, and carbonic acid formed or evolved. It is evident, that in all cases of tillage the seeds should be sown so as to be fully exposed to the influence of the air. And one cause of the unproductiveness of cold clayey adhesive soils is, that the seed is coated with matter impermeable to air. In sandy soils the earth is always sufficiently pene- trable by the atmosphere ; but in clayey soils there can scarcely be too great a mechanical division of parts in the process of tillage. Any seed not fully supplied with air, always produces a weak and diseased plant. The process of malting which has been already refer- red to, is merely a process in which germination is ar- tificially produced; and in which the starch of the coty- Jedon is changed into sugar; which sugar is afterwards, by fermentation, converted into spirit. It is very evident from the chemical principles of ger- mination, that the process of malting should be carried on no farther than to produce the sprouting of the radi- cle, and should be checked as soon as this has made its distinct appearance. If it is pushed to such a degree as air for their eggs which carries them from seas, or lakes into the mountain country; which induces them to move against the stream, and to endeavour to overleap weirs, mill-dams, and cataracts. 150 to occasion the perfect developement of the radiate and. 4 the plume, a considerable quantity of saccharine matter i will have been consumed in producing their expansion, and there will be less spirit formed in fermentation, or produced in distillation. As this circumstance is of some importance, I made in October 1806, an experiment relating toit. TL ascer- tained by the action of alcohol, the relative proportions of saccharine matter in two equal quantities of the same barley; in one of which the germination had proceeded so far as to occasion protrusion of the radicle to nearly a quarter of an inch beyond the grain in most of the specimens, and in the other of which it had been check- ed before the radicle was a line in length; the quantity of sugar afforded by the last was to that in the first near- ly as six to five. The saccharine matter in the cotyledons at the time ’ of their change into seed-leaves, renders them exceed- ingly liable to y the attacks of insects : this principle is at once a nourishment of plants and animals, and the great- est ravages are committed upon crops in this first stage of their growth. The turnip fly, an insect of the colyoptera génus, fixes itself upon the seed-leaves of the turnip at the time that they are beginning to perform their functions: and when the rough leaves of the plume are thrown forth, it is in- capable of injuring the plant to any extent. Several methods have been proposed for destroying the turnip fly, or for preventing it from injuring thé crop. It has been proposed to sow radish-seed with the tur- nip-seed, on the idea that the insect is fonder of the seed leaves of the radish than those of the turnip ; it is said that this plan has not been successful, and that the ~ fly feeds indiscriminately on both. There are several chemical menstrua which render the process of germination much more rapid, when the seeds have been steeped in them. As in these cases the seed- leaves are. quickly produced, and more speedily perform their functions, I proposed it as a subject of experiment to examine whether such menstrua might not be useful — in raising the turnip more speedily to that state in — which it would be secure from the fly; but the renally tg 151 ib proved that the practice was inadmissible; for seeds so treated, though they germinated much quicker, did not produce healthy plants, and often died soon after sprout- ing. I steeped radish seeds in September 1807, for twelve hours, in a solution of chlorine, and similar seeds in ve- ry diluted nitric acid, in very diluted sulphuric acid, in _ weak solution of oxysulphate of iron, and some in com- mon water. ‘The seeds in solutions of chlorine and oxysulphate of iron, threw out the germ in two days ; those in nitric acid in three days, in sulphuric acid in five, and those in water in seven days. But in the cases of premature germination, though the plume was very vigorous for a short time, yet it became at the end of a fortnight weak and sickly; and at that period less Vigorous in its growth than the sprouts which had been naturally developed, so that there can be scarcely any useful application of these experiments. ‘T'oo rapid growth and premature decay seem invariably connected in organized structures ; and it is only by following the slow operations of natural causes, that we are capable of making improvements. There is a number ef chemical substances which are very offensive and even deadly to insects, which do not injure, and some of which even assist vegetation. Se- veral of these mixtures have been tried with various suc- cess; a mixture of sulphur and lime, which is very de- structive to slugs, does not prevent the ravages of the fly on the young turnip crop. His Grace the Duke of ‘Bedford, at my suggestion, was so good as to order the experiment to be tried on a considerable scale at Wo- burn farm: the mixture of lime and sulphur was strew- ed over one part of the field sown with turnips; nothing was applied to the other part, but both were attacked nearly in the same manner by the fly. Mixtures of soot and quicklime, and urine and quick- lime, will probably be more efficacious. The volatile alkali given off by these mixtures is offensive to insects ; and they afford nourishment to the plant: Mr. T. A. Knight* informs me, that he has tried the method by * Mr. Knight has been so good as fo furnish me with the follow- ing note on this subject. - mind ammoniacal fumes with success butmore extensive iv il are necessary to establish its general efficacy. however, be safely adopted, for if it should me in ri stroying ‘the fly, it would at least be a useful manure to the land. | After the roots and leaves of the infant plant are form- ed, the cells and tubes throughout its structure become filled with fluid, which is usually supplied from the soil, and the function of nourishment is performed by the ac- tion of its organs upon the external elements. The con- stituent parts of the air are subservient to this process ; but, as it might be expected, they act differently under different circumstances. When a growing plant, the roots of which are sup- «“ The experiment which I tried the year before last, and last year, to preserve turnips from the fly, has not been sufficiently often re- peated to enable me to speak with any degree of decision; and last year all my turnips succeeded perfectly well. In consequence of your suggestion, when I had the pleasure to meet you some years ago at Holkham, that lime slacked with urine might possibly be found to kill, or drive off, the insects from a turnip crop, I tried that preparation in mixture with three parts of soot, which was put into a small barrel, with gimblet holes round it, to permit a certain quan- tity of the composition, about four bushels to an acre, tu pass out, and to fall into the drills with the turnip seeds. Whether it was by affording highly stimulating food to the plant, or giving some flavour which the flies did not like, I cannot tell; but in the year 1811, the adjoining rows were eaten away, and those to which the composition was applied, as above described, were scarcely at all touched. It is my intention in future to drill my crop in, first, with the composition on the top of the ridge; and then to sow at least a pound of seed, broad-cast over the whole ground. The expense of this will be ve- ry trifling, not more than 2s. per acre ; and the horse-hoe will instant- ly sweep away all the supernumeraries between the rows, should those escape the flies, to which however they will be chiefly attract- . ed; because it will always be found that these insects prefer turnips growing in poor, to those in rich ground. One advantage seems ta be the acceleration given to the growth of the plants, by the highly stimulative effects of the food they instantly receive as soon as their growth commences, and long before their radicles have reached the dung. The directions above given apply only to turnips sowed upon ridges, with the manure immediately under them; and I am quite certain, that in all soils turnips should be thus cultivated. The close vicinity of the manure, and the consequent short time required to carry the food into the leaf, and return the organizable matter to the — roots, are, in my hypothesis, points of vast importance; and the re- sults in practice are correspondent.” j 153 plied with a proper nourishment, is exposed in the pre- sence of solar light to a given quantity of atmospherical air, containing its due proportion of carbonic acid, the carbonic acid after a certain time is destroyed, and a certain quantity of oxygene is found in its place. If - new quantities of carbonic acid gas be supplied, the same result occurs; so that carbon is added to plants from the air by the process of vegetation in sunshine ; - and oxygene is added to the atmosphere. This circumstance is proved by a number of experi- ments made by Drs. Priestly, Ingenhouz and Wood- house, and M. 'T. de Saussure; many of which I have re- peated with similar results. I'he absorption of carbonic acid gas, and the production of oxygene are performed by the leaf; and leaves recently separated from the tree effect the change, when confined in portions of air con- taining carbonic acid; and absorb carbonic acid and produce oxygene, even when immersed in water hold- ing carbonic acid in solution. The carbonic acid is probably absorbed by the fluids in the cells of the green or parenchymatous part of the leaf; and it is from this part that oxygene gas is produ- ced during the presence of light. M. Sennebier found that the leaf, from which the epidermis was stripped off, continued to produce oxygene when placed in water, containing carbonic acid gas, and the globules of air rose from the denuded parenchyma; and it is shewn both from the experiments of Sennebier and Wood- house, that the leaves most abundant in parenchymatous parts produce most oxygene in water impregnated with carbonic acid. Some few plants* will vegetate in an artificial atmo- sphere, consisting principaily of carbonic acid, and ma- ny will grow for some time in air, containing from one- half to one-third ; but they are not so healthy as when supplied with smaller quantities of this elastic sub- stance. Plants exposed to light have been found to produce oxygene gas in an elastic medium and in water, con- * I found the Arenaria tenuifolia to produce oxygene in carbonic acid, which was nearly pure. 3 hie coe ne 154 taining vo carbonic acid gas; but in quantities much smaller than when carbonic acid gas was present. | In the dark no oxygene gas is produced by plants, whatever be the elastic medium to which they are expo- sed; and no carbonic acid absorbed. In most cases, on the contrary, oxygene gas, if it be present, is absorbed, and carbonic acid gas is produced. In the changes that take place in the composition of the organized parts, it is probable that saccharine com- pounds are principally formed during the absence of light; gum, woody fibre, oils, and resins during its pre- sence; and the evolution of carbonic acid gas, or its formation during the night, may be necessary to give greater solubility to certain ‘compounds i in the plant. I once suspected that all the carbonic acid gas produced by plants in the night, or in shade, might be owing to the decay of some part of the leaf, or epidermis; but the recent experiments of Mr. D. Ellis are opposed to this idea; and I found that a perfectly healthy plant of cele- _ ry, placed in a given portion of air for a few hours on- ly, occasioned a production of carbonic acid gas, and an absorption of oxygene. Some persons have supposed that plants exposed in the free atmosphere to the vicissitudes of sunshine and shade, light and darkness, consume more oxygene than they produce, and that their permanent agency upon air is similar to that of animals; and this opinion is espou- sed by the writer on the subject L have just quoted, in his ingenious researches on vegetation. But all expe- riments brought forwards in favour of this idea, and _ particularly his experiments, have been made under cir- cumstances unfavourable to accuracy of result. The plants have been confined and supplied with food in an unnatural manner; and the influence of light upon them has been very much diminished by the nature of the me- dia through which it passed. Plants confined in limit- ed portions of atmospheric air soon become diseased 5 their leaves decay, and by their decomposition they ra- pidly destroy the oxygene of the air. In some of the early experiments of Dr. Priestly before he was ac- quainted with the agency of light upon leaves, air that had supported combustion and. a epiration, was found 155 puritied by the growth of plants when they were expo- sed in it for successive days and nights; and his expe- riments are the more unexceptionable, as the plants, in many of them, grew in their natural states ; and shoots, or branches from them, only were introduced through water in the confined atmosphere. I have made some few researches on this subject, and I shall describe their results. On the 12th of July, 1800, I placed a turf four inches square, clothed with grass, principally meadow fox-tail, and white clover, in a porcelain dish, standing in a shallow tray filled with water; i then covered it with a jar of flint glass, con- taining 380 cubical inches of common air in its natural state. It was exposed in a garden, so as to be liable to the same changes with respect to light as in the common air. On the 20th of July the results were examined. There was an increase of the volume of the gas, amount- ing to fifteen cubical inches; but the temperature had changed from 64° to 71°; and the pressure of the at- mosphere, which on the 12th had been equal to the sup- port, of 30.4 inches of mercury, was now equal to that of 30.2. Some of the leaves of the white clover, and of the fox-tail were yellow, and the whole appearance of the grass less healthy than when it was first introdu- ced. A cubical inch of the gas, agitated in lime-wa- ter, gave a slight turbidness to the water; and the ab- sorption was not quite one-one hundred and fiftieth of its volume. 100 parts of the residual gas exposed to a solution of green sulphate of iron, impregnated with ni- irous gas, a substance which rapidly absorbs oxygene from air, occasioned a diminution to 80 parts. 100 parts of the air of the garden occasioned a diminution to 79 arts. - 2 If tbe results of this experiment be calculated upon it, it will appear that the air had been slightly deterio- rated by the action of the grasses. But the weather was unusually cloudy during the progress of the experiment; the plants had not been supplied in a natural manner with carbonic acid gas; and the quantity formed during the night, and by the action of the faded leaves, must have been partly dissolved by the water; and that this was actually the case, I proved by pouring lime-water 156 into the water, when an immediate precipitation Was 0c- casioned. The increase of azote I am inclined to attri- bute to common air disengaged from the water. The following experiment I consider as conducted under circumstances more analogous to those existing in nature. ment on this subject. ¢ 1 took an equal weight, 400 grains, of the leaves of two plants of endive, one bright green, which had grown fully exposed to light, and the other almost white, which had been secluded from light by being covered with a box; after being both acted upon for some time by boil- ing water, in the state of pulp, the undissolved matter was dried, and exposed to the action of warm alcohol. Whe matter from the green leaves gave it a tinge of olive; that from the pale leaves did not alterits colour. Scarcely any solid matter was produced by evaporation of the alcohol that had been digested on the pale leaves : where- as by the evaporation of that from the green leaves, a considerable residuum was obtained: five grains of which were separated from the vessel in which the evaporation was carried on; they burnt with flame, and appeared partly matter analogous to resin. 53 grains of woody fibre were obtained from the green leaves, and only 31 from the pale leaves. It has been mentioned in the Third Lecture, that the sap probably, in common cases, descends from the leaves into the bark; the bark is usually so loose in its texture, that the atmosphere may possibly act upon it in the cor- tical layers ; but the changes taking place in the leaves, appear sufficient to explain the difference between the products obtained from the bark and from the alburnum ; the first of which contains more carbonaceous matter than the last. When the similarity of the elements of different ve- getable products is considered, according to the views given in the Third Lecture, it is easy to conceive how the different organized parts may be formed from the same sap, according to the manner in which it is acted — on by heat, light and air. By the abstraction of oxy- gene, the different inflammable products, fixed and yvola- tile oils, resins, camphor, woody fibre, &c. may be pro- duced from saccharine or mucilaginous fluids ; and by the abstraction of carbon and hydrogene, starch, sugar, the different vegetable acids and substances soluble i in water, may be formed from highly combustible and in- convey the fragrance of the flower, consist of different proportions of the same essential elements, as the dense _ woody fibre; and both are formed by different changes in the same organs, from the same materials, and at the same time. M. Vauquelin has lately attempted to estimate the _ chemical changes taking place in vegetation, by analy- _ sing some of the organized parts of the horse-chesnut in their different stages of growth. He found in the buds collected, March 7, 1812, tanning principle, and _albuminous matter capable of being obtained separately, but when obtained, combining with each other. In the scales surrounding the buds, he found the tanning prin- ciple, a little saccharine matter, resin and a fixed oil. In the leaves fully developed; he discovered the same prin- ciples as in the buds; and in addition, a peculiar green resinous matter. The petals of the flower yielded a yellowish resin, saccharine matter, albuminous matter, and a little wax: the stamina afforded sugar, resin, and tannin. The young chesnuts examined immediately after their formation, afforded a large quantity of a matter which appeared to be a combination of albuminous matter and tannin. All the parts of the plant afforded saline com- Dinations of the acetic and phosphoric acids. M. Vauquelin could not obtain a sufficient quantity of the sap of the horse-chesnut for examination ; a cir- cumstance much to be regretted; and he has not stated the relative quantities of the different substances in the buds, leaves, flowers, and seeds. It is probable, how- ever, from his unfinished details, that the quantity of resinous matter is increased in the leaf, and that the white fibrous pulp of the chesnut is formed by the mu- tual action of albuminous and astringent matter, which probably are supplied by different cells or vessels. I have already mentioned* that the cambinm, from which the new parts in the trunk and branches appear to be formed, probably owes its powers of consolidation to _ the mixture of two different kinds of sap ; one of which 4 ae adie tala = cS. eae te. eee a : . *P, 104. soluble substances. Even the limpid volatile ails which | flows upwards from the roots; and other of wiitle pro- By bably descends from the leaves. I attempted, in May 4804, at the time the cambium was forming in the oak, to ascertain the nature of the action of the sap of the alburnum upon the juices of the bark. By perforating the alburnum in a young oak, and applying an exhaust- ing syringe to the aperture, I easily drew out a small quantity of sap. I could not, however, in the same way obtain sap from the bark. I was obliged to recur te the solution of its principles in water, by infusing a small quantity of fresh bark in warm water; the liquid obtain- ed in this wa y was highly coloured and astringent; and produced an immediate precipitate in the alburnous sap, the taste of which was sweetish, and slightly astringent, and which was colourless. ‘The increase of trees and plants must depend upon the quantity of sap which passes into their organs ; upon the quality of this sap; and on this modification by the principles of the atmosphere. Water, as it is the vehi- cle of the nourishment of the plant, is the substance ~ principally given off by the leaves. Dr. Hales found, that a sunflower, in one day of twelve hours, transpired by its leaves one pound fourteen ounces of water, all of which must have been imbibed by its roots. The powers which cause the ascent of the sap have been slightly touched upon in the Second and Third Lectures. ‘The roots imbibe fluids from the soil by ca- pillary attraction ; but this power alone is insufficient to— account for the rapid elevation of the sap into the leaves. This is fully proved by the following fact detailed by Dr. Hales, Vol. I. of the Vegetable Statics, page 114. A vine branch of four or five years old was cut through, “and a glass tube carefully attached to it; this tube was bent as a siphon, and filled with quicksilver; so that the force of the ascending sap could be measured by its ef- fect in elevating the quicksilver. In a few days it was found, that the sap had been propelled forwards with so much force, as to raise the quicksilver to 38 inches, which is a force considerably superior to that of the usual pressure of the atmosphere. Capillary attraction can only be exerted by the surfaces of small vessels, and can never raise a fluid into tubes above the vessels peg selves. ah me Gs _ Mr. Knight’s opinion, that the contractions and expan- sions of the silver grain in the alburnum, are the most efficient cause of the ascent of the fluids contained in its pores and vessels. ‘The views of this excellent phy- siologist are rendered extremely probable by the facts he has brought forward in support of them. Mr. Knight found that a very small increase of temperature was suf- ficient to cause the fibres of the silver grain to separate from each other, and that a very slight diminution of heat produced their contraction. ‘The sap rises most vigorously in spring and autumn, at the time the tempe- rature is variable; and if it be supposed, that in expand- ing and contracting, the elastic fibres of the silver grain exercise a pressure upon the cells and tubes containing the fluid absorbed by the capillary attraction of the roots, this fluid must constantly move upwards towards the points where a supply is needed. The experiments of Montgolfier, the celebrated in- ventor of the balloon, have shewn that water may be raised almost to an indefinite height by a very small force, provided its pressure be taken off by continued divisions in the column of fluid. This principle, there is great reason to suppose, must operate in assisting the ascent of the sap in the cells and vessels of plants which have no rectilineal communication, and which every: where oppose obstacles to the perpendicular pressure of the sap. The changes taking place in the leaves and buds, and the degree of their power of transpiration, must be in- _ timately connected likewise with the motion of the sap upwards. This is shewn by several experiments of Dr. Hales. A branch from an apple tree was separated and in- troduced into water, and connected with a mercurial gage. When the leaves were upon it, it raised the mer- cury by the force of the ascending juices to four inches ; but a similar branch, from which the leaves were remo- ved, scarcely raised it a quarter of an inch. Those trees, likewise, whose leaves are soft and of a spongy texture, and porous at their upper surfaces, dis- played by far the greatest powers with regard to the ele- vation of the sap. | Phsby I ; ' 4 Men sed 1 4 ms Oy / fi aN i with sae “4 i v C ve ea Whey bias 166 Se ae abd Sh ‘The same accurate philosopher whom I have just quoted, found that the pear, quince, cherry, walnut, peach, gooseberry, water-elder, and sycamore, which have all soft and unvarnished leaves, raised the mercu- ry under favourable circumstances from three to six inches. Whereas the elm, oak, chesnut, hazel, sallow, and ash, which have firmer and more glossy leaves, raised the mercury only from one to two inches. And the evergreens and trees bearing varnished leaves, scarcely at all affected it; particularly the laurel and the lauristinus. It will be proper to mention the facts which shew, that in many cases fluids descend through the bark; they are not of the same unequivocal nature’as those which de- monstrate the ascent of the sap through the alburnum; yet many of them are satisfactory. M. Baisse placed branches of different trees in an in- fusion of madder, and kept them there for a long time. He found in all cases, that the wood became red before the bark ; and that the bark began to receive no tinge till the whole of the wood was coloured, and till the leaves were affected ; and that the colouring matter first appeared above, in the bark immediately in contact with the leaves. Similar experiments were made by M. Bonnet, and with analogous results, though not so perfectly distinct as those of M. Baisse. Du Hamel found, that in different species of the pine and other trees, when strips of bark were removed, the upper part of the wound only emitted fluid, whilst the lower part remained dry. This may likewise be observed in the summer in fruit- . trees, when the bark is wounded, the alburnum remain- ing untouched. I have mentioned in the Third Lecture, that when new bark is formed to supply the place of a ring that has been stripped off, it first makes its appearance upon the upper edge of the wound, and spreads slowly down- wards ; and no new matter appears from below rising up- wards, if the experiment has been carefully performed. I say carefully performed ; because, if any of the inte- rior cortical layer be suffered to remain communicating with the upper edge, new bark covered with epidermis 167 “will form below this, and appear as if protruded upon the naked alburnum, and formed within the wound; and such a circumstance would give rise to erroneous con- clusions. In the summer of 1804, I examined some elms at Ken- sington. “The bark of many of them had been very much injured, and, in some cases, more than a square foot had been stripped off. In most of the wounds the for- mation of the new cortical layers was from above, and | gradually extending downwards round the aperture ; but in two instances there had been very distinctly a for- mation of bark towards the lower edge. I was, at first, very much surprised at this appearance, so contradicto- — ry to the general opinion; but, on passing the point of a pen-knife along the surface of the alburnum, from below upwards, [ found that a part of the cortical layer, which was of the colour of the alburnum, had remained com-: municating with the upper edge of the wound, and that the new bark had formed from this layer. I have had no opportunity of looking at the trees lately; but I doubt not that the phenomenon may still be observed; for some years must elapse before the new formations will be complete. In accounting for the experiment of M. Palisot de Beauvois, mentioned in the Third Lecture, it may be supposed that the cortical fluid flowed down the albur- num upon the insulated bark, and thus occasioned its increase; or it may be conceived that the bark itself contained sufficient cortical fluid at the time of its sepa- ration to form new parts by its action upon the albur- nous fluid. . The motion of the sap through the bark seems prin- cipally te depend upon gravitation. When the watery particles have been considerably dissipated by the tran-_ spiring functions of the leaves, and the mucilaginous, inflammable, and astringent constituents, increased by the agency of heat, light, and air, the continued impulse upwards from the alburnum, forces the remaining in- spissated fluid into the cortical vessels, which receive no other supply. In these, from its weight, its natural tendency must be to descend; and the rapidity of the descent must depend upon the general consumption of the fluids of the bark in the living processes of vegeta- tion; for there is every reason to believe, that no fluid — passes into the soil through the roots ; and it is impos- sible to conceive a free lateral communication between the absorbent vessels of the alburnum in the roots, and the transporting or carrying vessels of the bark ; for if such a communication existed, there is no reason why the sap should notrise through the bark as well as through the alburnum ; for the same physical powers would then operate upon both. Some authors have supposed that the sap rises in the alburnum, and descends through the bark in consequence of a power similar to that which produces the circula- tion of the blood in animals; a force analogous to the muscular force in the sides of the vessels. Dr. Thomson in his System of Chemistry, has stated a fact which he considers as demonstrating the irratibi- lity of living vegetable systems. When astork of spurge (Euphorbia peplis) is separated by two incisions from its leaves and roots, the milky fluid flows through both sections. Now, says the ingenious author, it is impos- sible that this could happen without the living action of the vessels, for they cannot have been more than full ; and their diameter is so small, that if it were to conti- nue unaltered, the capillary attraction would be more than sufficient to contain their contents, and, consequent- ly, not a drop would flow out. Since, therefore, the li- quid escapes, it must be driven out by a force different from a common physical force. To this reasoning it may be answered, that the sides of all the vessels are soft, and capable of collapsing by gravitation, as veins do in animal systems long after they have lost all their vitality ; which is an effect to- tally different from vital or irritable action; and the phenomenon may be compared to that of puncturing a vessel of elastic gum filled with fluid, both above and below ; the fluid will make its way through the aper- tures, though in much larger quantity from the lowest, “which I have found is likewise the: case with the spurge. Dr. Barton has stated, that plants grow more vigor- ously in water in which a little camphor has been infu- 169 sed. This has been brought forward as a fact in favour of the irritability of the vegetable tubular system. It is said, that camphor can only be conceived to actas a stimulus, by increasing the living powers of the vessels,. and causing them to contract with more energy. But this kind of speculation is very unsatisfactory. Cam- phor, we know, has a disagreeable pungent taste, and powerful smell; but physicians are far from being agreed whether it is a stimulant or sedative, even in its operation upon the human bedy. We should have no right whatever, even supposing the irritability of ve- getables proved, to conclude, that because camphor as- sisted the growth of plants, it acted on their living pow- ers; and it is not right to infer the existence of a pro- perty proved in no other way, from the operation of an- certain qualities. That camphor may assist the growth of plants it is easy to conceive ; and why should we not consider its efficacy as similar to the efficacy of saccharine and mu- cilaginous matter, and particularly of oils, to which it is nearly allied in composition; and which afford food to the plant, and not stimulus; which are materials of as- similation, and not of excitement ? The arguments in favour of a contraction similar to muscular action have not then much weight; and besides, there are direct facts which render the opinion highly improbable. When a single branch of a vine or other tree is intro- duced in winter into a hot-house, the trunk anc the other branches remaining exposed to the cold atmosphere, the sap will soon begin to move towards the buds in the heated branch; these buds will gradually unfold them- selves, and begin to transpire; and at length open into leaves. Now if any peculiar contractions of the sap ves- sels or cells were necessary for the ascent of the sap in the vessels, it is not possible that the application of heat to a single branch should occasion irritable action to take place in a trunk many feet removed from it, or in roots fixed in the cold soil: but allowing that the energy of heat raises the fluid merely by diminishing its gravity, increasing the facility of capillary action, and by produ- cing an expansion of the fibres of the silver grain, the 4 . “4170 phenomenon i is in perfect unison with the views advan- ced in the preceding part of this Lecture. we The ilex, or evergreen oak, preserves its leaves theta the winter, even w hen grafted upon the common oak; and in consequence of the ‘operation of the leaves, there is a certain motion of the sap towards the ilex, which, as in the last case, seems to be inconsistent with the theo- ry of irritable action. It is impossible to peruse any considerable part of the Vegetable Statics of Hales, without receiving a deep impression of the dependence of the motion of the sap upon common physical agencies. In the same tree this sagacious person observed, that in a cold cloudy morn- ing when no sap ascended, a sudden change was pro- duced by a gleam of sunshine, of half an hour; and a vigorous motion of the fluid. The alteration of the wind from south to the north immediately checked the effect. On the coming on of a cold afternoon after a hot day, the sap that had been rising began to fall. A warm shower and a sleet storm produced opposite effects. Many of his observations likewise shew, that the dif- ferent powers which act on the adult tree, produce dif- ferent effects at different seasons. | ‘Thus, in the early spring, before the buds expand, the variations of the: temperature, and changes of the state of the atmosphere with regard to moisture and dry- ness, exert their great effects upon the expansions and contractions of the vessels; and then the tree is in what is called by gardeners its bleeding season. When the leaves are fully expanded, the great deter- mination of the sap is to these new organs. And hence a tree which emits sap copiously from a wound whilst the buds are opening, will no longer emit it in summer when the leaves are perfect; but in the variable wea- ther, towards the end of autumn, when the leaves are falling, it will again possess the power of bleeding in a very slight degree in the warmest days; but at no other times. In all these civcumstances there is nothing analogous to the irritable action of animal systems. In animal systems the heart and arteries are in con- stant pulsation. Their functions are unceasingly per~ 174 formed in all climates, and in all seasons 5 in winter, as well as in spring; upon the arctic snows, and under the tropical suns. ‘They neither cease in the periodical noc- turnal sleep, common to most animals ; 3 nor in the long sleep of winter, peculiar to a few species. The power is connected wake animation, is limited to beings pos- sessing the means of voluntary locomation ; it co-exists with the first appearance of vitality; it disappears only with the last spark of life. Vegetables may be truly said to be living systems, in this sense, that they possess the means of converting the elements of common matter into organized structures, both by assimilation and reproduction ; but we must not suffer ourselves to be deluded by the very extensive ap- plication of the word life, to conceive in the life of plants, any power similar to that producing the life of animals. In calling forth the vegetable functions, common physi- cal agents alone seem to operate; but in the animal sys- tem these agents are made subservient to a superior principle. To give the argument in plainer language, there are few philosophers “who would be inclined to as- sert the existence of any thing above common matter, any thing immaterial in the vegetable economy. Such a doctrine is worthy only of a poetic form. The imagi- nation may easily give Dryads to our trees, and Sylphs to our flowers ; but neither Dryads nor Sylphs can be admitted in vegetable physiology; and for reasons near- ly as strong, irritability and animation ought to be ex- cluded. As the operation of the different physical agents upon the sap vessels of plants ceases, and the fluid becomes quiescent, the materials dissolved in it by heat, are de- posited upon the sides of the tubes now considerably diminished in their diameter ; and in consequence of this deposition, a nutritive matter is provided for the first wants of the plant in early spring, to assist the opening of their buds, and their expansion, when the motion from the want of leaves is as yet feeble. This beautiful principle in the vegetable economy was first pointed out by Dr. Darwin; and Mr. Knight has given a number of experimental elucidations of it. “Mr. Knight made numerous incisions into the albur- num of the sycamore and the birch, at different heights ;_ and in examining the sap that flowed from them, he found it more sweet and mucilaginous in proportion as the aperture from which it flowed was elevated 5; which he could ascribe to no other cause than to its having dissolved sugar and mucilage, which had been stored up— through the winter. He examined the alburnum in different poles of oak in the same forest; of which some had been felled in winter, and others in summer; and he always found most soluble matter in the wood felled in winter, and its specific gravity was likewise greater. In all perennial trees this circumstance takes place 3 and likewise in grasses and shrubs. The joints of the perennial grasses contain more saccharine and mucila- sinous matter in winter than at any other season; and this is the reason why the fiorin or Agrostis alba, which abounds in these joints, affords so useful a winter food. — | The roots of shrubs contain the largest quantity of nourishing matter in the depth of winter; and the bulb in all plants possessing it, isthe recepticle in which nou- rishment is hoarded up during winter. In annual plants the sap seems to be fully exhausted of all its nutritive matter by the production of flowers and seeds, and no system exists by which it can be pre- served. When perennial grasses are cropped very close by feeding cattle late in autumn, it has been often observed by farmers, that they never rise vigorously in the spring; and this is owing to the removal of that part of the stalk which would have afforded them concrete sap, their first nourishment. | Ship builders prefer for their purposes that kind of oak timber afforded by trees that have had their bark stripped off in spring, and which have been cut in the autumn or winter following. ‘The reason of the supe- riority of this timber is, that the concrete sap is expend- ed in the spring in the sprouting of the leaf; and the circulation being destroyed, it is not formed anew; and ay Eo iwood having its pores free from saccharine matter, ! is less liable to undergo fermentation from the action of moisture and air. In perennial trees a new alburnum, and consequently a new system of vessels, is annually produced, and the nutriment for the next year deposited in them; so that the new buds like the plume of the seed, are supplied with a reservoir of matter essential to their first de- velopment. The old alburnum is gradually converted into heart- wood, and being constantly pressed upon by the expan- ‘sive force of the new fibres, becomes harder, denser, and at length loses altogether its vascular structure ; and. in a certain time obeys the common laws of dead mat- ter, decays, decomposes, and is converted into aeriform and carbonic elements; into those principles from which it was originally formed. The decay of the heart-wood seems to constitute the great limit to the age and size of trees. And in young branches from old trees, it is much more liable to de- compose than in similar branches from seedlings. This is likewise the case with grafts. The graft is only nou- rished by the sap of the tree to which it is transferred ; its properties are not changed by it: the leaves, blos- soms and fruits are of the same kind as if it had vege- tated upon its parent.stock. ‘The only advantage to be gained in this way, is the affording to a graft from an old tree a more plentiful and healthy food than it could have procured in its natural state; it is rendered for a time more vigorous, and produces fairer blossoms and richer fruits. But it partakes not merely of the obvi- ous properties, but likewise of the infirmities and dis- positions to old age and decay, of the tree whence it sprung. This seems to be distinctly shewn by the observations and experiments of Mr. Knight. He has, in a number of instances, transferred the young scions and healthy shoots from old esteemed fruit-bearing trees to young seedlings. ‘They flourished for two or three years; but they soon became diseased and sickly like their parent trees. | It is from this cause that so many of the apples for ao “merly celebrated for their taste and their . foes uses in the — manufacture of cider are gradually deteriorating, and many will soon disappear. The golden pippin, the red _ streak, and the moil, so excellent in the beginning of the last century, are now in the extremest stage of their de- cay; and however carefully they are ingrafted, they merely tend to multiply a sickly and exhausted variety. The trees possessing the firmest and the least porous heart-wood are the longest in duration. In general, the quantity of charcoal afforded by woods, offers a tolerably accurate indication of their durability : those most abundant in charcoal and earthy matter are most permanent; and those that contain the largest pro- portion of gaseous elements are the most destructible. Amongst our own trees, the chesnut and the oak are pre-eminent as to durability; and the chesnut affords rather more carbonaceous matter than the oak. In old gothic buildings these woods have been some- times mistaken one for the other; but they may be easily known by this circumstance, that the pores in the albur- num of the oak are much larger and more thickly set, and are easily distinguished; whilst the pores in the chesnut require glasses to be seen distinctly. In consequence of the slow decay of the heart-wood of the oak and chesnut, these trees under favourable cir- cumstances attain an age which cannot be much short of 4000 years. The beech, the ash, and the sycamore, most likely never live half as long. The duration of the apple tree is not, probably, much more than 200 years; but the pear tree, according to Mr. Knight, lives through double this period ; most of our best apples are supposed to have been introduced into Britain by a fruiterer of Hen- ry the Kighth, and they are now in a state of old age. The oak and chesnut decay much sooner in a moist situation, than in a dry and sandy soil; and their tim- ber is less firm. The sap vessels in such cases are more expanded, though less nourishing matter is carried into them ; and the general texture of the formations of wood necessarily less firm. Such wood splits more easily, and is more liable to be affected by variations in the state of the atmosphere. } P77 F! Kearny $2. L Granite 2 Gneis 3 Micaceous Shis Stenite as ent putts of animals: or which ane Moana in their : at ood, their secretions, or their excrements, are gelatine, fil ne; | mucus, fatty, or oily matter, albumen, urea, uric acid, and different acid, saline, and earthy matters. Ste a Of these gelatine is the substance which when com- bined with water forms jelly. It is very liable to pu-— trefaction. According to M. M. Gay Lussac and The- — nard, it is composed of 47.88 of carbon. 27.207 — oxygene. 7.914 —hydrogene. 16.998 These proportions cannot be considered as definite, for they do not bear to each other the ratios of any sim- ple multiples of the number representing the elements; the case seems to be the same with other animal com- pounds : and even in vegetable substances, in general, as appears from the statements given in the Third Lec- ture, the proportions are far from having the same sim- ple relations as in the binary compounds capable of be- ing made artificially, such as acids, alkalies, oxides, and in salts. Fibrine constitutes the basis of the muscular fibre of animals, and a similar substance may be obtained from recent fluid blood; by stirring it with a stick the fibrine will adhere to the stick. It is not solublein water; but by the action of acids, as Mr. Hatchett has shewn, it be- comes soluble, and analogous to gelatine. It is less disposed to putrefy than gelatine. According to M. M. Gay Lussac and Thenard, 100 parts of fibrine contain Of Carbon” - 53.360 Oxygene’ - 19.685 Hydrogene 7.024 Azote - 19.954 Mucus is very analogous to vegetable gum in its cha- racters ; and as Dr. Bostock has stated, it may be ob- tained by evaporating saliva. No experiments have been made upon its analysis 3 but it is probably similar to gum incomposition. It is capable of undergoing pu- trefaction, but less rapidly than fibrine. Animal fat and oils have not been accurately analy- zed; but there is great reason to suppose that their com- Mi ye i : 7 7 | - 189 id position is analogous to that of similar substances froux the vegetable kingdom. Albumen has been already referred to, and its analy- — sis stated in the Third Lecture. Urea may be obtained by the evaporation of human -urine, till it is of the consistence of a syrup; and the ac- — tion of alcohol on the crystalline substance which forms — when the evaporated matter cools. In this way a solu-’ tion of urea in alcohol is procured, and the alcohol may be separated from the urea by heat. Urea is very solu- ble in water, and is precipitated from water by diluted nitric acid in the form of bright pearl-coloured crystals ; this property distinguishes it from all other animal sub- stances. According to Fourcroy and Vauquelin, 100 parts of urea when distilled yield 92.027 parts of carbonate of ammonia. 4.608 carburetted hydrogene gas. 3.225 of charcoal. Urea, particularly when mixed with albumen or gela- tine, readily undergoes putrefaction. Uric acid, as has been shewn by Dr. Egan, may be obtained from human urine by pouring an acid into it; rh and it often falls down from urine in the form of brick-- coloured crystals. It consists of carbon, hydrogene, oxygene, and azote : but their proportions have not yet been determined. Uric acid is one of the animal sub- stances least liable to undergo the process of putrefac- tion. According to the different proportions of these princi- ples in animal compounds, so are the changes they un- dergo different. When there is much saline or earthy matter mixed or combined with them, the progress of their decomposition is less rapid than when they are principally composed of fibrine, albumen, gelatine, or urea. The ammonia given off from animal compounds in putrefaction may be conceived to be formed at the time of their decomposition by the combination of hydrogene and azote; except this matter, the other products of pu- trefaction are analogous to those afforded by the fer- ' mentation of vegetable substances; and the soluble sub- stances formed ‘abound in the elements, which are the Ny m consuident parts of vegetables, in iste hydrogene, Me and oxygene. “Whenever manures consist principally of matter solu- ble i in water, it is evident that their fermentation or pu- trefaction should be prevented as much as possible ; and the only cases in which these processes can be useful, ) _ are when the manure consists principally of vegetable or animal fibre. ‘The circumstances necessary for the pu- trefaction of animal substances are similar to those re- quired for the fermentation of vegetable substances; a temperature above the freezing point, the presence of water, and the presence of oxygene, at least in the first stage of the process. To prevent manures from decomposing, they should — be preserved dry, defended from the contact of air, and kept as cool as possible. Salt and alcohol appear to owe their powers of pre- serving animal and vegetable substances to their attrac-. tion for water, by which they prevent its decomposing action, and likewise to their excluding air. 'The use of ice in preserving animal substances is owing to its keep- ing their temperature low. The efficacy of M. Appert’s method of preserving animal and vegetable substances, an account of which has been lately published, entirely depends upon the exclusion of air. ‘This method is by filling’ a vessel of tin plate or glass with the meat or ve- getables; soldering or cementing the top so as to render the vessel air tight ; and then keeping it half immersed in a vessel of boiling water for a sufficient time to ren- der the meat or vegetables proper for food. In this last process it is probable that the small quantity of oxygene remaining in the vessel is absorbed; for on opening a tinned iron canister which had been ‘filled with raw beef and exposed to hot water the day before, I found that the minute quantity of elastic fluid which could be pro- cured from it, was a mixture of carbonic acid gas and azote. Where meat or vegetable food is to be preserved on a large ‘scale, for the use of the navy or army for in-- stance, I am inclined to believe, that by forcibly throw- ing a quantity of carbonic acid, hydrogene, or azote, into the vessel, by means of a compressing pump, similar to that used for making artificial Seltzer water, any change " igh" NWA A 494 nis in + the substance would be more effectually prevented. No elastic fluid in this case would have room to form by the decomposition of the meat; and the tightness and strength of the vessel would be ‘proved by the pro- cess. No putrefaction or fermentation can go on with- out the generation of elastic fluid; and pressure would probably act with as much efficacy as cold in the preser- vation of animal or vegetable food. As different manures contain different proportions of the elements necessary to vegetation, so they require a different treatment to enable them to produce their full effects in agriculture. 1 shall therefore describe in de- tail the properties and nature of the manures in common use, and give some general views respecting the best modes of preserving and applying them. All green succulent plants contain saccharine or mu- cilaginous matter, with woody fibre, and readily ferment. They cannot, therefore, if intended for manure, be used too soon after their death. When green crops are to be employed for enriching a soil, they should be ploughed in, if it be possible, when in flower, or at the time the flower is beginning to appear, for it is at this period that they contain the largest quantity of easily soluble matter, and that their leaves are most active in forming nutritive matter. Green crops, pond weeds, the paring of hedges or ditches, or any kind of fresh vegetable matter, requires no pre- paration to fit them for manure. ‘The decomposition slowly proceeds beneath the soil ; the soluble matters are gradually dissolved, and the slight fermentation that goes on checked by the want of a free communication of air, tends to render the woody fibre soluble without occasion- ing the rapid glissipation of elastic matter. When old pastures are broken up and made arable, not only has the soil been enriched- by the death and slow decay of the plants-which have left soluble matters in the’soil; but the leaves and roots of the grasses liv- ing at the time and occupying so large a part of the _ surface, afford saccharine, mucilaginous, and extractive _ matters, which become immediately the food of the crop, and the gradual decomposition affords a supply for suc- cessive years. Re er 192 Rape cake, which is used with great success as a ma- nure, contains a large quantity of mucilage, some albu- minous matter, and a small quantity of oil. This ma- nure should be used recent, and kept as dry-as possible before it is applied. It forms an excellent dressing for turnip crops ; and is most ceconomically applied by be- ing thrown into the soil’ at the same time with the seed. Whoever wishes to see this practice in its highest de- sree of perfection, should attend Mr. Coke’s annual sheep-shearing at Holkham. Malt dust consists chiefly of the infant radicle sepa- rated from the grain. I have never made any experi- ment upon this manure ; but there is great reason to sup- pose it must contain saccharine matter, and this will ac- count for its powerful effects. Like rape cake it should be used as dry as possible, and its fermentation prevented. Linseed cake is too valuable as a food for cattle to be much employed as a manure; the analysis of linseed was referred to in the Third Lecture. The water in which flav and hemp are steeped for the purpose of ob- taining the pure vegetable fibre, has considerable ferti- lizing powers. It appears to contain a substance ana- logous to albumen, and likewise much vegetable extrac- tive matter. It putrefies very readily. A certain de- sree of fermentation is absolutely necessary to obtain the flax and hemp in a proper state ; the water to which they have been exposed should therefore be used as a manure as soon as the vegetable fibre is removed from it. Sea weeds, consisting of different species of fuci, al- gx, and conferve, are much used as a manure on the sea coasts of Britain and Ireland. By digesting the common fucus, which is the sea weed usually most abun- dant on the coast, in boiling water, I obtainéd from it one-eighth of a gelatinous substance which had charac- ters similar to mucilage. A quantity distilled gave — nearly four-fifths of its weight of water, but no ammo- — nia; the water had an empyreumatic and slightly sour taste; the ashes contained sea salt, carbonate of soda, and carbonaceous matter. The gaseous matter afforded was small in quantity, principally carbonic acid and gas- _ cous oxide of carbon, with a little hydro-carbonate. This manure is transient in its effects, and does not last 198 Pibifor more than a single crop, which is easily accounted for from the large quantity of water, or the elements of water, it contains. It decays without producing heat when exposed to the atmosphere, and seems, as it were, to melt down and dissolve away. I have seen a large heap entirely destroyed in less than two years, nothing remaining but a little black fibrous matter. I suffered some of the firmest part of a fucus to remain in a close jar, containing atmospheric air, for a fortnight: in this time it had become very much shrivelled; the sides of the jar were lined with dew. ‘The air examined was found to have lost oxygene, and contained carbonic acid gas, Sea weed is sometimes suffered to ferment before it is used; but this process seems wholly unnecessary, for there is no fibrous matter rendered soluble in the pro- cess, and a part of the manure is lost. The best farmers in the west of England use it as fresh as it can be procured; and the practical results of this mode of applying it are exactly conformable to the theory of its operation. ‘Che carbonic acid formed by its incipient fermentation must be partly dissolved by the water set free in the same process; and thus be- come capable of absorption by the roots of plants. The effects of the sea weed, as manure, must princi- pally depend upon this carbonic acid, and upon the so- Juble mucilage the weed contains ; and 1 found that some fucus which had fermented so as ‘to have lost about half its weight, afforded less than one-twelfth of mucilaginous matter ; from which it may be fairly concluded that some of this substance is destroyed in fermentation.’ . _ Dry straw of wheat, oats, barley, beans, and peas, and spoiled hay, or any other similar kind of dry vege- table matter, is, in all cases, useful manure. In gene- ral, such substances are made to ferment before they are employed, though it may be doubted whether the prac- tice should be indiscriminately adopted. From 400 grains of dry barley straw f obtained eight grains of matter soluble in water, which had a brown colour, and tasted like mucilage. » From 400 grains of wheaten straw I obtained five grains of a similar sub- stance. Bh ‘Vhere can be no doubt that the straw of different crops immediately ploughed into the ground affords nourish- ment to plants; but there is an objection to this method of using straw from the difficulty of burying long straw, and from its rendering the husbandry foul. When straw is made to ferment, it becomes a more. manageable manure; but there is likewise, on the whole, a great loss of nutritive matter. More manure is per- haps supplied for a single crop; but the land is less im- proved than it would be, supposing the whole of the ve- getable matter could be finely divided and mixed with the soil. It is usual to carry straw that can be employed for no other purpose to the dunghill, to ferment, and decom- pose ; but it is worth experiment, whether it may not be more economically applied when chopped small by a proper machine, and kept dry till it is ploughed in for the use of a crop. In this case, though it would decom- pose much more slowly, and produce less effect at first, yet its influence would be much more lasting. Mere woody fibre seems to be the only vegetable mat- ter that requires fermentation to render it nutritive to plants. ‘Tanners’ spent bark is a substance of this kind. Mr. Young, in his excellent Essay on Manures, which gained him the Bedfordian medal of the Bath Agricul- tural Society, states, that spent bark seemed rather to injure than assist vegetation 3’? which he attributes to the astringent matier that itcontains. But, in fact, it is freed from all soluble substances, by the operation of water in the tan-pit; and if injurious to vegetation, the effect is probably owing to its agency upon water, or to its mechanical effects. Lt is a substance very absorbent and retentive of moisture, and yet not penetrable by the roots of plants. Inert peaty matter is a substance of the same kind. It remains for years exposed to water and air without un- dergoing change, and in this state yields little or no nou- rishment to plants. Woody fibre will not ferment unless some substances ave mixed with it, which act the same part as the muci- lage, sugar, and extractive or albuminous matters, with which it is usually associated in herbs and succulent ve- ‘ 495 Betab last Lord Meadowbank has, judiciously recom. mended a mixture of common farm-yard dung for the purpose of bringing peats into fermentation; any putres- -cible or fermentable substance will answer the end; and the more a substance heats, and the more readily it fer- ments, the better will it be fitted for the purpose. Lord Meadowbank states, that one part of dung is sufficient to bring three or four parts of peat into a state in which it is fitted to be applied to land ; but of course the quantity must vary according to the nature of the dung and of the peat. In cases in which some living vegetables are mixed with the peat, the fermentation will be more readily effected. Tanners’ spent bark, shavings of wood and saw- dust, will probably require as much “dung to bring ee into fermentation as the worst kind of peat. Woody fibre may be likewise prepared so as to be- come a manure, by the action of lime. This subject I shall discuss in the next Lecture, as it follows natural- ly another series of facts, relating to the effects of lime in the soil. It is evident from the analysis of woody fibre by M. M. Gay Lussac and Thenard, (which shews that it con- sists principally of the elements of water and carbon, the - carbon being in larger quantities than in the other vege- table compounds) that any process which tends to ab- stract carbonaceous matter from it, must bring it nearer in composition to the soluble principles; and this is done in fermentation by the absorption of oxygene, and pro- duction of carbonic acid; and a similar effect, it will be shewn, is produced by lime. Wood-ashes, imperfectly formed, that is, wood-ashes containing much charcoal, are said to have been used with success as a manure. A part of their effects may be owing to the slow and gradual consumption of the charcoal, which seems capable, under other circum- stances than those of actual combustion, of absorbing oxygene so as to become carbonic acid. In April, 1803, I enclosed some well-burnt charcoal in a tube half filled with pure water, and half with com- mon air; the tube was her metically sealed. 1 opened the tube. under pure water, in the spring of 1804, at a were eee the samie as ah the Gonna eeement of periment. Some water rushed in; and on expelling a little air by heat from the tube, and analyzing it, it was found to contain only seven per cent. of oxygene. The water in the tube, when mixed with lime-water, produ- ced a copious precipitate; so that carbonic acid had evi- dently been formed and dissolved by the water. Manures from animal substances, in general, require no chemical preparation to fit them for the soil. The great object of the farmer is to blend them with the earthy constituents in a proper state of division, and‘to prevent their too rapid decomposition. The entire parts of the muscles of land animals are not commonly used as manure, though there are many cases in which such an application might be easily made. Horses, dogs, sheep, deer, and other quadrupeds that have died accidentally, or of disease, after their skins are separated, are often suffered to remain exposed to the air, or immersed in water, till they are destroyed by birds or beasts of prey, or entirely decomposed ; and in this case, most of their organizable matter is lost for the land in which they lie, anda considerable portion of it employed in giving off noxious gases to the atmo- sphere. By covering dead animals with five or six times their bulk of soil, mixed with one part of lime, and suffering them to remain for a few months; their decomposition would impregnate the soil with soluble matters, so as to render it an excellent manure; and by mixing a little fresh quick lime with it at the ‘time of its remove al, the disagreeable effluvia will be ina great measure destroy- ed; and it might be applied in the same way as any other manure to crops. Fish forms a powerful manure, in whatever state it is applied; but it cannot be ploughed in two fresh, though the quantity should be limited. Mr. Young records an experiment, in which herrings spread over a field, and ploughed in for wheat, produced so rank a crop, that it was entirely laid before haryest. The refuse pilchards in Cornwall are used throughout — the county as a manure, with excellent effects. They Me are usually mixed with sand or soil, and sometimes with sea weed, to prevent them from raising too luxuriant a crop. The effects are perceived for several years. In the fens of Lincolnshire, Cambridgeshire, and Norfolk, the little fishes called sticklebacks, are caught in the shallow waters in such quantities, that they form a great article of manure in the land bordering on the fens. It is easy to explain the operation of fish as a manure. The skin is principally gelatine ; which from its slight state of cohesion, is readily soluble in water: fat or oil is always found in fishes, either under the skin or in some of the viscera; and their fibrous matter contains all the essential elements of vegetable substances. Amongst oily substances, blubber has been employed as amanure. It is most useful when mixed with clay, sand, or any common soil, so as to expose a large sur- face to the air, the oxygene of which produces soluble matter from it. Lord Somerville used blubber with great success at his farm in Surrey. It was made into a heap with soil, and retained its powers of fertilizing for several successive years. The carbon and hydrogene abounding in oily sub- stances, fully account for their effects; and their dura- bility is easily explained from the gradual manner in which they change by the action of air and water. Bones are much used as a manure in the neighbour- hood of London. After being broken, and boiled for grease, they are sold to the farmer. ‘The more divided they are, the more powerful are their effects. The ex- pense of grinding them in a mill would probably be re- paid by the increase of their fertilizing powers; and in the state of powder they might be used in the drill hus- bandry, and delivered with the seed, in the same man- ner as rape cake. Bone dust, and bone shavings, the refuse of the turn- ing manufacture, may be advantageously employed in the same way. The basis of Bone is constituted by earthy salts, prin- cipally phosphate of lime, with some carbonate of lime and phosphate of magnesia; the easily decomposable substances in bone are fat, gelatine, and cartilage, which seems of the same nature as coagulated albumen, 498 According to the analysis of K ourcroy and Vauquelin, Ox bones are composed %: Of decomposable animal matter = - 51m — phosphate of lime - - - 37.7 — carbonate of lime - “ - 10:5 — phosphate of Magnesia - - 1.3 400 M. Merat Guillot has given the following estimate of the composition of the bones of different animals. Bone of Calf -_ Horse Sheep Elk Hog Hare Pullet Pike Carp Horses’ teeth The remaining parts of the 100 must be considered as decomposable animal matter. Horn is a still more powerful manure than bone, as it contains a larger quantity of decomposable animal matter. From 500 grains of ox horn, Mr. Hatchett ob- tained only 1.5 grains of earthy residuum, and not quite half of this was phosphate of lime. ‘The shavings or turnings of horn form an excellent manure, though they are not sufficiently abundant to be in commonuse. The animal matter in them seems to be of the nature of co- agulated albumen, and it is slowly rendered soluble by the action of water. The earthy matter in horn, and still more that in bones, prevents the too rapid decom- position of the animal matter, and renders it very dura- ble in its effects. Harr, woollen rags, and feathers are all analogous in composition, and principally consist of a substance simi- Sera , 199 lar to albumen, united to gelatine. 'I'his is shewn by the ingenious researches of Mr. Hatchett. The theory of their operation is similar to that of bone and horn _ shavings. 5; The refuse of the different manufactures of skin and _ leather form very useful manures ; such as the shavings of the currier, furriers’ clippings, and the offals of the tan-yard, and of the glue-maker. The gelatine con- tained in every kind of skin is in a state fitted for its gradual solution or decomposition ; and when buried in the soil, it lasts for a considerble time, and constantly affords a supply of nutritive matter to the plants in its _ neighbourhood. | Blood contains certain quantities of all the principles found in other animal substances, and is consequently a very good manure. It has been already stated that it contains fibrine; it likewise contains albumen: the red particles in it which have been supposed by many fo- reign chemists to be coloured by iron in a particular state of combination with oxygene and acid matter, Mr. Brande considers as formed of a peculiar animal sub- stance, containing very little iron. The scum taken from the boilers of the sugar bakers, and which is used as manure, principally consists of - bullock’s blood, which has been employed for the pur- pose of separating the impurities of common brown su- gar, by means of the coagulation of its albuminous mat- ter by the heat of the boiler. | Vhe different species of corals, coralines, and sponges, must be considered as substances of animal origin. . From the analysis of Mr. Hatchett, it appears that all these substances contain considerable quantities of a matter analogous to coagulated albumen; the sponges afford likewise gelatine. »According to Merat Guillot, white coral contains equal parts of animal matter and carbonate of lime; red coral 46.5 of animal matter, and 53.5 of carbonate of lime ; articulated coraline 51 of animal matter, and 49 of carbonate of lime. These substances are, I believe, never used as ma- _ nure in this country, except in cases when they are ac- _ cidently mixed with sea weed; but it is probable that. ; ‘ my | fata Na (hey) iy 4 taaieoralings might be advantageously employed, as the -are found in considerable quantity on the rocks, and bot- — toms of the rocky pools on many parts of our coast, __ where the land gradually declines towards the sea; and — they might be detached by hoes, and collected without much trouble. bi, Amongst excrementations, animal substances used as manures, wrine is the one upon which the greatest num- ber of chemical experiments have been made, and the nature of which is best understood. \ ‘The urine of the cow contains, according to the ex- periments of Mr. Brande, : Water - - - - - 65 yy: 7 . Phosphate of lime - - “ 3 a Muriates of potassa and ammonia = 45 | Sulphate of potassa - +) mn Carbonates, potassa, and ammonia 4 i Urea - - . - - 4. i The urine of the horse, according to Fourcroy and r Vauquelin, contains, Of Carbonate of lime - . 44 Be) — Carbonate of soda - - 9 Be —~ Benzoate of soda - . 24 Mg — Muriate of potassa . . 9 Bol — Urea - - - - 4) ty — Waiter and mucilage - - 940 In addition to these substances, Mr. Brande found in it phosphate of lime. | The urine of the ass, the camel, the rabbit, and do- — mestic fowls have been submitted to different experi- — - ments, and their constitution have been found similar. — In the urine of the rabbit, in addition to most of the in- — Mi gredients above mentioned, Vanquelin detected gelatine; — vi and the same chemist discovered uric acid in the urine ~ os of domestic fowls. i, BY 3 Human urine contains a greater variety of constituents — it than any other species examined. a Urea, uric acid, and another acid similar to it in na-— {ure called rosacic acid, acetic acid, albumen, ‘gelatine, a resinous matter, and various salts are found in it. BY the’state of the body, and the nature of the food and - drink made use of. In many cases of disease there is a - much larger quantity of gelatine and albumen than usual in the urine; and in diabetes it contains sugar. It is probable that the urine of the same animal must likewise differ according to the different nature of the food and drink used ; and this will account for discordan- cies in some of the analyses that have been published on _ the subject. Urine is very liable to change and to undergo the pu- trefactive process; and that of carnivorous animals more rapidly than that of graminivorous animals. In proper-. tion as there is more gelatine and albumen in urine, so in proportion does it putrefy more quickly. ‘The species of urine that contain most albumen, ge- latine, and urea, are the best as manures; and all urine contains the essential elements of vegetables in a state of solution. During the putrefaction of urine the greatest part of the soluble animal matter that it contains is destroyed 5 it should consequently be used as fresh as possible ; but if not mixed with solid matter, it should be diluted with water, as when pure it contains too large a quantity of animal matter to form a proper fluid nourishment for ab- sorption by the roots of plants. Putrid urine abounds in ammoniacal salts ; and thou gh _ less active than fresh urine, is a very powerful manure, According to a recent analysis published by Berzeli- us, 1000 par rts of urine are composed of Water - - - - ~ 933 Urea - - - : - = 80.4 Uric acid . - . : 4 Muriate of ammonia, free lactic acid, lactate of ammonia and 17.44 animal matter - 3 The remainder different salts, phosphates, sulphates, and muriates. _ Amongst excrementitious solid substances used as ma- nures, one of the most powerful is the dung of birds that feed on animal food, particularly the dung of sea birds. The guano, which is used to a great extent in Seuth cc ee; oe hori i nS eye aha reed MY Weiter DG, mm hg wey il WS Pah a ‘f - America, and which is the manure which fertilizes the sterile plains of Peru, is a production of this kind, It exists abundantly, as we are informed by M. Humbr on the small islands in the South Sea, at Chinche, Ho, Iza, and Arica. 50 vessels are laden with it annually at Chinche, each of which carries from 1500 to 2000 cu- bical feet. It is used as a manure only in very smalh quantities 5 and particularly for crops of maize. I made some experiments on specimens of guano sent from South America to the Board of Agriculture in 1805. It ap- peared as a fine brown powder; it blackened by heat, and gave off strong ammoniacal fumes ; treated with ni- tric acid it afforded uric acid. In 1806 M. M. Four- croy and Vauquelin published an elaborate analysis of guano. ‘They state that it contains a fourth part of its weight of uric acid, partly saturated with ammonia, and partly with potassa; some phosphoric acid combined with the basis, and likewise with lime. Small quanti- ties of sulphate and muriate of potassa, a little fatty matter, and some quartzose sand. It is easy to explain its fertilizing properties: from its composition it might be supposed to be a very pow- erful manure. It requires water for the solution of its soluble matter to enable it to produce its full beneficial effect on crops. ; _ The dung of sea birds has, I believe, never been used asa manure in this country; but jt is probable, that even the soil of the small islands on our coast much frequent- ed by them, would fertilize. Some dung of sea birds _ brought from a rock on the coast of Merionethshire, produced a powerful but transient effect on grass. It was tried, at my request, by Sir Robert Vaughan at Nannau. ! The rains in our climate must tend very much to in- jure this species of manure, where it is exposed to them, soon after its deposition; but it may probably be found in great perfection in caverns or clefts in rocks, haunt- ed by cormorants and gulls. I examined ‘some recent cormorant’s dung which I found on a rock near Cape Li- gard in Cornwall. It had not at all the appearance of the guano; was of a grayish white colour; had a very fo- tid smelt like that of putrid animal matter : when acted on by quicklime it gave abundance of ammonia treated 4 ies nitric acid it yielded uric acid. _ Night soil, it is well known, is a very powerful ma- nure, and very liable to decompose. It differs in com- position; but always abounds in substances composed of carbon, hydrogene, azote, and oxygene. From the — analysis of Borzelius, it appears that a part of it is al- ways soluble in water; and in whatever state it is used, whether recent or fermented, it supplies abundance of food to plants. The disagreeable smell of night soil may be destroy- ed by mixing it with quicklime; and if exposed to the | atmosphere in thin layers strewed over with quicklime in fine weather, it speedily dries, is easily pulverised, and in this state may-be used in the same manner as rape cake, and delivered into the furrow with the seed. The Chinese, who have more practical knowledge of the use and application of manures than any other f peo- ple existing, mix their night soil with one-third of its weight of a fat marle, make it into cakes, and dry it by exposure to the sun. ‘These cakes, we are informed by the French missionaries, have no disagreeable smell, and form a common article of commerce of the em- ire. The earth, by its absorbent powers, probably prevents, to a certain extent, the action of moisture upon the dung, and likewise defends it from the effects of air. After night soil, pigeons’ dung comes next in order, as to fertilizing power. I digested 100 grains of pi-. geons’ dung, in hot water for some hours, and obtained _ from it 23 grains of soluble matter; which afforded abun- dance of carbonate of ammonia by distillation; and left carbonaceous matter, saline matter principally common salt, and carbonate of lime as a residuum. Pigeons’ dung when moist readily ferments, and after a fermenta- tion contains less soluble matter than before: from 100 parts of fermented pigeons’ dung, I obtained only eight parts of soluble matter, which gave proportionally less” carbonate of ammonia in distillation than recent pigeons’ dung. It is evident that this manure should be applied as — new as possible ; and when dry, it may be employed in ALE lan Ve Se 1) OA ae TOMY Ub ihe nA ht the same maiuer as the other manures capable of bei * pulverised. ‘Wari cally examined by M. M. Hinhof and Thaer. They The soil ia woods where great flocks of wood-pigeons- roost, is often highly impregnated with their dung, and it cannot be doubted, would form a valuable manure. Z have found such soil yield ammonia when distilled with lime. In the winter likewise it usually contains — abundance of vegetable matter, the remains of decayed ° leaves; and the dung tends to bring the vegetable mat- ‘ter into a state of solution. The dung of domestic fowls approaches very nearly in its nature to pigeons’ dung. Uric acid has been found in it. It gives carbonate of ammonia by distillation, and immediately yields soluble matter to water. Itis very liable to ferment. The dung of fowls is employed in common with that of pigeons by tanners to bring on a slight degree of pu- trefaction in skins that are to be used for making soft Jeather; for this purpose the dung is diffused through - water. In this state it rapidly undergoes putrefaction, © and brings on a similar change in the skin. ‘The ex- crements of dogs are employed by the tanner with simi- lar effects. In all cases, the contents of the grainer, as the pit is called in which soft skins are prepar ed by dung, | mnust form a very useful manure. Rabbits’ dung has never been analysed. It is used with great success ag a manure by Mr. Fane, who finds it profitable to keep rabbits in such a manner as to pre- serve their dung. It is laid on as fresh as possible, and is found better the less it has fermented. Vhe dung of cattle, owen, and cows, has been chemi- found that it contained matter soluble in water; and that it gave in fermentation nearly the same products as ve- getable substances, absorbing oxygene and producing Eighonic acid gas. * The recent dung of sheep, and of deer, afford, when a Jong boiled in water, soluble matters, which equal from two to three per cent. of their weight. I have examin- ed these soluble substances procured: by solution and evaporation; they contain a very small quantity of mat- . ter analogous to animal mucus; and are prince com- ¢: oN ia y, VA 1 | osed of a bitier extract, soluble both in water and in we | alcohol. ‘They give ammoniacal fumes by distillation; — and appear very little in composition. I watered some blades of grass for several successive days with a solution of these extracts ; they evidently be-_ came greener in consequence, and grew more vigorously thangrass in other respects, under the same circumstances. The part of the dung of cattle, sheep, and deer, not soluble in water, appears to be mere woody fibre, and precisely analogous to the residuum of those vegetables that form their food after they have been deprived of all their soluble materials. The dung of horses gives a brown fluid, which when evaporated, yields a bitter extract, which affords ammo- niacal fumes more copiously than that from the dung of oxen. If the pure dung of cattle is to be used as manure, like the other species of dung which have been men- tioned, there seems no reason why it should be made to ferment except in the soil; or if suffered to ferment, it should be only in a very slight degree. The grass in the neighbourhood of recently voided dung, is always coarse and dark green ; some persons have attributed this to a noxious quality in unfermenting dung; but it seems to be rather the result of an excess of food furnished to the plants. The question of the proper mode of the application of the dung of horses and cattle, however, properly be-— longs to the subject of composite manures, for it is usually mixed in the farm-yard with straw, offal, chaff, and various kind of litter; and itself contains a large proportion of fibrous vegetable matter. A slight incipient fermentation is undoubtedly of use in the dunghill; for by means of it a disposition is brought on in the woody fibre to decay and dissolve, when it is carried to the land, or ploughed into the soil ; and woody fibre is always in great excess in the refuse of the farm. Too great a degree of fermentation is, however, very prejudicial to the composite manure in the dunghill; it is better that there should be no fermentation at all be-. fore the manure is used, than that it should be carried too far. This must be obvious from what ha Dm a Sh i hy Masnete Oe OT ANA a Le ANID aR iv ashale GON Mea CORE ” a t a ) +3 1s Mn * - ready stated in this Lecture. ‘The excess of fermenta- 3 tion tends to the destruction and dissipation of the most useful part of the manure; and the ultimate results of this process are like those of combustion. It is a common practice amongst farmers to suffer the farm-yard dung to ferment till the fibrous texture of the vegetable matter is entirely broken down; and till the manure becomes perfectly cold, and so soft as to be easily cut by the spade. Independent of the general theoretical views unfa- vourable to this practice, founded upon the nature and composition of vegetable substances, there are many ar- guments and facts which shew that it is prejudicial to the interests of the farmer. var During the violent fermentation which is necessary for reducing farm-yard manure to the state in which it is called short muck, not only a large quantity of fluid, but likewise of gaseous matter, is lost; so much so, that the dung is reduced one half, or two thirds in weight ; and the principal elastic matter disengaged, in carbonic acid with some ammonia; and both these, if retained by the moisture in the soil, as has been stated before, are capable of becoming a useful nourishment of plants. — In October, 1808, I filled a large retort capable of containing three pints of water, with some hot ferment- ing manure, consisting principally of the litter and dung of cattle; I adapted - a small receiver to the retort, and connected the whole with a mercurial pneumatic appa- ratus, so as to collect the condensible and elastic fluids which might rise from the dung. The receiver soon became lined with dew, and drops began in a few hours to trickle down the sides of it. Elastic fluid likewise was generated ; in three days thirty-five cubical inches had been formed, which, when analyzed, were found to contain twenty-one cubical inches of carbonic acid, the remainder was hydrocarbonate mixed with some azote, probably no more than existed in the common air in the receiver. "The fluid matter collected in the receiver at the same time amounted to nearly half an — ounce. It had a saline taste, and a disagreeable smell, — and contained some acetate and carbonate of ammonia. — y?. * ' Finding such products given off from fermenting lit- ter, I introduced the beak of another retort filled with similar dung very hot at the time, in the soil amongst the roots of some grass in the border of a garden; in ‘Jess than a week ‘a very distinct effect was produced on the grass ; upon the spot exposed to the influence of the matter disengaged in fermentation, it grew with much more luxuriance than the grass in any other part of the garden. Besides the dissipation of gaseous matter when fer- mentation is pushed to the extreme, there is another dis- advantage in the loss of heat, which, if excited in the soil, is useful in promoting the germination of the seed, and in assisting the plant in the first stage of its growth, © when it is most feeble and most liable to disease: and the fermentation of manure in the soil must be particu- larly favourable to the wheat crop in preserving a genial temperature beneath the surface late in autumn, and du- ring winter. Again, it is a general principle in chemistry, that in all cases of decomposition, substances combine much more readily at the moment of their disengagement, than after they have been perfectly formed. And in fermentation beneath the soil the fluid matter produced is applied instantly, even whilst it is warm, to the or- gans of the plant, and consequently is more likely to be efficient, than in manure that has gone through the pro- cess; and of which all the principles have entered inte new combinations. In the writings of scientific agriculturists, a great mass — of facts may be found in favour of the application of farm-yard dung in a recent state. Mr. Young, in the Essay on Manures, which I have already quoted, ad- duces a number of excellent authorities in support of the plan. Many, who doubted, have been lately con- vinced ; and perhaps there is no subject of investigation in which there is such a union of theoretical and prac- ‘tical evidence. I have myself, within the last ten years, witnessed a number of distinct proofs on the subject. I shall content myself with quoting that which ought to have, and which I am sure will have, the greatest weight ' amongst agriculturists, Within the last seven years Mr. i ” Coke has entirely. given up the ma a forms me, that his crops have been since as g00 as the ae on his farm, of applying fermented dung; ever were, and that his manure goes nearly twice as far. A great objection against slightly fer mented dung is, that weeds spring up more luxuriantly where it is applied. If there are seeds carried out in the dung they cee will germinate; but it is seldom that this can be the case to any extent ; and if the land is not cleansed of weeds, any kind of manure fermented or unfermented will occasion their rapid growth.: If slightly fermented farm-yard dung is used as a top dressing for pastures, the long straws and unfermented vegetable matter re- maining on the surface should be removed as soon as the grass begins to rise vigorously, by raking, and carried - back to the dunghill: in this case no manure will be lost, and the husbandry will be at once clean and eco- nomical. In cases when farm-yard dung cannot be immediate- ly applied to crops, the destructive fermentation of if should be prevented as much as possible; the principles on which this may be effected have been already allu- ded to. | The surface should be defended as much as possible from the oxygene of the atmosphere ; a compact marle, or a tenacious clay, offers the best protection against the air; and before the dung is covered over, or, as it were, sealed up, it should be dried as much as possible. If the dung is found at any time to heat strongly, it should be tur ned over, and cooled by exposure to air. Watering dunghills is sometimes recommended . for checking the progress of fermentation ; but this practice is inconsistent with just chemical views. It may cool the dung for a short time; but moisture, as I have be- fore stated, is a principal agent in all processes of de- Composition. Dry fibrous matter will never ferment. Water is as necessary as air to the process; and to sup- _ ply it to fermenting dung, is to supply an agent which will hasten its decay. In ail cases when dung is fermenting, there are sim- ple tests by which the rapidity of the procesé, and con-, sequently the injury done, may be discovered. ee My We vs ro pie If a thermometer plunged into the dung does not rise ~ _ to above 100 degrees of Fahrenheit, there is little dan- ger of much aer ‘iform matter flying off. If the tempe- _rature is higher, the dung should be immediately spread - abroad. When a piece of paper moistened in muriatic acid held over the steams arising from a dunghill gives dense fumes, it is a certain test that the decomposition is go- ing too far, for this indicates that volatile alkali is dis- engaged. When dung is to be preserved for any time, the si- tuation in which it is kept is of importance. It should, if possible, be defended from the sun. To preserve it under sheds would be of great use; or to make the site of a dunghill on the north side of a wall. The floor on which the dung is heaped, should if possible, be pa- ved with flat stones; and there should be a little incli- nation from each side towards the centre, in which there should be drains connected with a small well, furnished - with a pump, by which any fluid matter may be col- lected for the use of the land. It too often happens that a dense mucilaginous and extractive fluid is suffer- ed to drain away from the dunghill, so as to be entirely lost to the farm. Street and road dung, and the sweepings of houses, may be all regarded as composite manures : the consti- tution of them is necessarily various, as they are deri- ved from a number of different substances. These ma- nures are usually applied in a proper manner, without being fermented. Soot, which is principally formed from the combus- tion of pit-coal or coal, generally contains likewise sub- stances derived from animal matters. This is a very powerful manure. It affords ammoniacal salts by dis- tillation, and yields a brown extract to hot water, of a bitter taste. It likewise contains an-empyreumatic oil. Its great basis is charcoal, in a state in which it is ca- pable of being rendered soluble by the action of oxy- gene and water. This manure is well fitted to be used in the dry state, thrown into the ground with the seed, and requires no preparation. od Aes hie ys Yi Hi) my Wi sah bah LO dae YM Hy " ” hatte ; AL i r 210 ing The doctrine of the proper application of manures from organised substances, offers an illustration of an important part of the osconomy of nature, and of the happy order in which it is arranged. The death and decay of animal substances tend to resolve organised forms into chemical constituents ; and the pernicious effluvia disengaged in the process seem to point out the propriety of burying them in the soil, Where they are fitted to become the food of vegetables. The fermentation and putrefaction of organised sub- stances in the free atmosphere are noxious processes ; beneath the surface of the ground they are salutary operations. In this case the food of plants is prepared where it can be used 5 and that which would offend the senses and injure the health, if exposed, is converted by gradual processes into forms of beauty and of use- fulness ; the foctid gas is rendered a constituent of the aroma of the flower, and what might be poison, becomes nourishment to animals and to man. LECTURE VIL. iW On Manures of mineral Origin, or fossile Manures 5 their Preparation, and the Manner in which they Act. Of Lime in its different States ; Operation of Lime as a Manure and a Cement ; different Combi- nations of Lime. Of Gypsum ; Ideas respecting its Use. Of other Neutro-saline Compounds, employed as Manures. Of Alkalies and alkaline Salts ; of Common Salt. THe whole tenor of the preceding Lectures shews, that a great variety of substances contributes to the growth of plants, and supplies the materials of their nourishment. "The conversion of matter that has be- longed to living structures into organised forms is a pro- cess that can be easily understood ; but it is more dif- ficult to follow those operations by which earthy and saline matters are consolidated in the fibre of plants, and by which they are made subservient to their func- tions. Some inquirers adopting that sublime generali- zation of the ancient philosophers, that matter is the same in essence, and that the different substances con- sidered as elements by chemists, are merely different arrangements of the same indestructible particles, have endeavoured to prove, that all the varieties of the prin- ciples found in plants, may be formed from the substan- ces in the atmosphere ; and that vegetable life is a pro- cess in which bodies that the analytical philosopher is unable to change or to form, are constantly composed and decomposed. ‘These opinions have not been ad- vanced merely as hypotheses; attempts have been made to support them by experiments. M. Schrader and Mr. Braconnet, from a series of distinct investigations, have arrived at the same conclusions. They state that different seeds sown in fine sand, sulphur, and metallic oxides, and supplied only with atmospherical air and water, produced healthy plants, which by analysis yielded various earthy and saline matiers, which either were not contained in the seeds, or the material in which they grew; or which were contained only in much smaller quantities in the seeds: and hence they conclude that they must have been formed from air or water, in consequence of the agencies of the living organs of the plant. A The researches of these two gentlemen were conduct- ed with much ingenuity and address; but there were cir- cumstances which interfered with their results, which they could not have known, as at the time their labours were published they had not been investigated. T have found that common distilled water is far from: being free from saline impregnations. In analysing it by Voltaic electricity, I procured from it alkalies and earths; and many of the combinations of metals with chlorine are extremely volatile substances. When dis- tilled water is supplied in an unlimited manner to plants, it may furnish to them a number of different substances, which though in quantities scarcely perceptible in the water, may accumulate in the plant, which probably per- spires only absolutely pure water. | In 1801, I made an experiment on the growth of oats, supplied with a limited quantity of distilled water ina soil composed of pure carbonate of lime. The soiland the water were placed in a vessel of iron, which was in- cluded in a large jar, connected with the free atmosphere by a tube, so curved as to prevent the possibility of any dust, or fluid, or solid matter from entering into the jar. My object was to ascertain whether any siliceous earth would be formed in the process of Vegetation; but the oats grew very feebly, and began to be yellow before any flowers formed : the entire plants were burnt, and their ashes compared with those from an equal number of grains of oats. Less silicious earth was given by the plants than by the grains; but their ashes yielded much more carbonate of lime. ‘That there was less siliceous earth I attribute to the circumstance of the husk of the oat being thrown off in germination; and this is the part which most abounds in silica. Healthy green oats taken from a growing crop, in a field of which the soil was a ' fine sand, yielded siliceous earth in a much greater pro- 218 portion than an equal weight of the corn artificially raised. ae The general results of this experiment are very much opposed to the idea of the composition of the earths, by _ plants, from any of the elements found in the atmo- sphere, or in water; and there are other facts contra- dictory to the idea. Jacquin states that the ashes of glass wort (Salsola soda,) when it grows in inland situations, afford the vegetable alkali; when it grows on the sea shore, where compounds which afford the fossile or ma- rine alkali are more abundant, it yields that substance. Du Hamel found, that plants which usually grow on the sea shore, made small progress when planted in soils containing little common salt. The sunflower, when growing in lands containing no nitre, does not afford _ that substance; though when watered by a solution of nitre, it yields nitre abundantly. The tables of de Saus- sure, referred to in the Third Lecture, shew that the ashes of plants are similar in constitution to the soils in which they have vegetated. De Saussure made plants grow in solutions of differ- ent salis, and he ascertained, that in all cases, certain portions of the salts were absorbed by the plant, and found unaltered in their organs. Even animals do not appear to possess the power of forming the alkaline and earthy substances. Dr. For- dyce found, that when canary birds, at the time they were laying eggs, were deprived of access to carbonate of lime, their eggs had soft shells; and if there is any process for which nature may be conceived most likely to supply resources of this kind, it is that connected with the reproduction of the species. As the evidence on the subject now stands, it seems fair to conclude, that the different earths and saline sub- stances found in the organs of plants are supplied by the soils in which they grow; and in no cases composed by new arrangements of the elements in air or water. What may be our ultimate view of the laws of chemis- try, or how far our ideas of elementary principles may be simplified, it is impossible to say. Wecan only rea- son from facts. We cannot imitate the powers of com- position belonging to vegetable structures; but at least 244 we can understand them: and as far as our researches have gone, it appears, that in vegetation compound forms are uniformly produced from simpler ones; and the elements in the soil, the atmosphere, and the earth absorbed and made parts of beautiful and diversified structures. ' The views which have been just developed lead to correct ideas of the operation of these manures which are not necessarily the result of decayed organised bo- dies, and which are not composed of different propor- tions of carbon, hydrogene, oxygene, and azote.—They must produce their effect, either by becoming a constitu- ent part of the plant, or by acting upon its more essen- tial food, so as to render it more fitted for the purposes of vegetable life. Vhe only substances which can with propriety be called fossile manures, and which are found unmixed with the remains of any organised beings, are certain alkaline earths or alkalies, and their combinations. The only alkaline earths which have been hitherto applied in this way, are lime and magnesia. Potassa _ and soda, the two fixed alkalies, are both used in certain of their chemical compounds. I shall state in succession such facts as have come to my knowledge respecting each of these bodies in their applications to the purposes of agriculture; but I shall enlarge most upon the sub- ject of lime; and if I should enter into some details which may be tedious and minute, I trust, my excuse will be found in the importance of the inquiry; and it is one which has been greatly elucidated by late disco- veries. The most common form in which lime is found on ‘the surface of the earth, is in a state of combination with carbonic acid or fixed air. Uf a piece of lime- stone, or chalk, be thrown into a fluid acid, there will be an effervescence. This is owing to the escape of the carbonic acid gas. The lime becomes dissolved in the liquor. When limestone is strongly heated, the carbonic acid gas is expelled, and then nothing remains but the pure alkaline: earth; in this case there i is a loss of weight; and if the fire has been very high, it approaches to one- 215 half the weight of the stone; but in common cases, lime- stones, if well dried before burning, do not lose much more than from 35 to 40 per cent., or from seven “" eo parts out of twenty. I mentioned, in discussing the agencies of the atmo- sphere upon vegetables, in the beginning of the Fifth Lecture, that air always contains carbonic acid gas, and that lime is precipitated from water by this substance. When burnt lime is exposed to the atmosphere, in a cer- tain time it becomes mild, and is the same substance as that precipitated from lime water ; it is combined with carbonic acid gas. Quicklime, when first made, is caustic and burning to the tongue, renders vegetable blues green, and is soluble in water; but when combined with carbonic acid it looses all these properties, its solubili- ty and its taste: it regains its power of effervescing, and. becomes the same chemical substance as chalk, or lime- stone. Very few limestones, or chalks, consist entirely of lime and carbonic acid. The statuary marbles, or cer- tain of the rhomboidal spars, are almost the only pure species ; and the different properties of limestones, both as manures and cements, depend upon the nature of the ingredients mixed in the limestone ; for the true calca- reous element, the carbonate of lime, is uniformly the same in nature, properties, and effects, and consists of one proportion of carbonic acid 44.4, and one of lime When a limestone does not copiously effervesce in acids, and is sufficiently hard to scratch glass, it contains siliceous, and probably aluminous earth. When it is deep brown, or red, or strongly coloured of any of the shades of brown or yellow, it contains oxide of iron. When it is not sufficiently hard to scratch glass, but ef- fervesces slowly, and makes the acid in which it effer- -vesces milky, it contains magnesia. And when it is black, and emits a foetid smell if rubbed, if contains coaly or bituminous matter. The analysis of limestones is not a difficult matter ; and the proportions of their constituent parts may be ea- sily ascertained, by the processes described in the Lec- ture on the Analysis of Soils; and usually with suffi- 216 cient accuracy for all the purposes of the farmer, by the fifth process. | *. Before any opinion can be formed of the manner in which the different ingredients in limestone modify their properties, it will be necessary to consider the operation of the pure calcareous element as a manure, and as a cement. _ Quicklime in its pure state, whether in powder, or dissolved in water, is injurious to plants.—I have in se- veral instances killed grass by watering it with lime wa- ter.—But lime, in its state of combination with carbonic acid, as is evident from the analyses given in the Fourth Lecture, is a useful ingredient in soils. Calcareous earth is found in the ashes of the greater number of plants; and exposed to the air, lime cannot long conti- nue caustic, for the reasons that were just now assign- ed, but soon becomes united to carbonic acid. When newly burnt lime is exposed to air, it soon falls into powder; in this case it is called slacked lime; and the same effect is immediately produced by throwing, wa- ter upon it, when it heats violently, and the water dis- appears. Slacked lime is merely a combination of lime, with about one third of its weight of water; i. e. fifty-five parts of lime absorb seventeen parts of water; and in this case it is composed of a definite proportion of wa- ter, and is called by chemists hydrate of lime ; and when hydrate of lime becomes carbonate of lime by long ex- posure to air, the water is expelled, and the carbonic acid gas takes its place. When lime, whether freshly burnt or slacked, is mix- ed with any moist fibrous vegetable matter, there is a strong action between the lime and the vegetable mat- ter, and they form a kind of compost together of which a part is usually soluble in water. By this kind of operation, lime renders matter which was before comparatively inert, nutritive; and as char- coal and oxygene abound in all vegetable matters, it becomes at the same time converted into carbonate of lime. jh nty Mild lime, powdered limestone, marles, or chalks, have no action of this kind upon vegetable matter; by 247 their action they prevent the too rapid decomposition of substances already dissolved ; but they have no tenden- _ ey to form soluble matters. It is obvious from these circumstances, that the ope- ration of quicklime, and marle or chalk, depends upon principles altogether different.—Quicklime in being ap- plied to land, tends to bring any hard vegetable matter’ that it contains into a state of more rapid decomposition and solution, so as to render it a proper food for plants. —Chalk and marle, or carbonate of lime, will only im- prove the texture of the soil, or its relation to absorp- tion ; it acts merely as one of its earthy ingredients.— Quicklime, when it becomes mild, operates in the same manner as chalk; but in the act of becoming mild, it prepares soluble out of insoluble matter. It is upon this circumstance that the operation of lime in the preparation of wheat crops depends; and its ef- ficacy in fertilizing peats, and in bringing into a state of cultivation all soils abounding in hard roots or dry fibres, or inert vegetable matter. The solution of the question whether quicklime ought to be applied to a soil, depends upon the quantity of in- ert vegetable matter that it contains. ‘The solution of the question, whether marle, mild lime, or powdered limestone, ought to be applied, depends upon the quan- tity of calcareous matter already in the soil. All soils are improved by mild lime, and ultimately by quicklime, which deo not effervesce with acids; and sands more than clays. When a soil deficient in calcareous matter contains much soluble vegetable manure, the application of quick- lime should always be avoided, as it either tends to de- compose the soluble matters by uniting to their carbon and oxygene so as to become mild lime, er it combines with the soluble matters, and forms compounds having less attraction for water than the pure vegetable sub- stance. The case is the same with respect to most animal manures; but the operation of the lime is different in different cases, and depends upon the nature of the ani- mal matter. Lime forms a kind of insoluble soap with oily matters, and then gradually decomposes them by EE a separating from them oxygene and carbon. It combines likewise with the animal acids, and probably assists their decomposition by abstracting carbonaceous matter from them combined with oxygene ; and, consequently, it must render them less nutritive. It tends to diminish likewise the nutritive powers of albumen from the same causes; and always destroys, to a certain extent, the efficacy of animal manures, either by combining with certain of their elements, or by giving to them new ar- rangements. Lime should never be applied with ani- mal manures, unless they are too rich, or for the pur- pose of preventing noxious effluvia, as in certain cases mentioned in the last Lecture. It is injurious when mix- ed with any common dung, and tends to render the ex- tractive matter insoluble. I made an experiment on this subject: I mixed a quantity of brown soluble extract, which was procured from sheeps’ dung with five times its weight of quick- lime. J then moistened them with water; the mixture heated very much; it was suffered to remain for four- teen hours, and was then acted on by six or seven times its bulk of pure water: the water, after being passed - through a filtre, was evaporated to dryness; the solid matter obtained was scarcely coloured, and was lime mixed with a little saline matter. In those cases in which fermentation is useful to pro- duce nutriment from vegetable substances, lime is always efficacious. I mixed some moist tanner’s spent bark with one-fifth of its weight of quicklime, and suffered them to remain together in a close vessel for three months ; the lime had become coloured, and was effervescent : when water was boiled upon the mixture, it gained a tint of fawn colour, and by evaporation furnished a fawn- coloured powder, which must have consisted of lime united to vegetable matter, for it burnt when strongly heated, and left a residuum of mild lime. The limestones containing alumina and silica are less fitted for the purposes of manure than pure limestones ; but the lime formed from them has no noxious quality. Such stones are less efficacious, merely because they fur- nish a smaller quantity of quicklime. | I mentioned bituminous limestones. ‘There is very ” 219 seldom any considerable portion of coaly matter in these stones ; never as much as five parts in 100; but such limestones make very good lime. The carbonaceous matter can do no injury to the land, and may, under certain circumstances, become a food of the plant, as is evident from what was stated in the last Lecture. The subject of the application of the magnesian lime- stone is one of great interest. It had been long known to farmers in the neighbour- hood of Doncaster, that lime made from a certain lime- stone applied to the land, often injured the crops con- siderably, as I mentioned in the introductory Lecture. Mr. ‘Tennant, in making a series of experiments upon this peculiar calcareous substance, found that it contain- ed magnesia; and on mixing some calcined magnesia with soil, in ‘which he sowed different seeds, he found that they either died, or vegetated in a very imperfect manner, and the plants were never healthy. And with great justice and ingenuity he referred the bad effects of the peculiar limestone to the magnesian earth it con- tains. found that there were cases in which this magnesian limestone was used with good effect. Amongst some specimens of limestone which Lord Somerville put into my hands, two marked as peculiar- ly good proved to be magnesian limestones. And lime made from the Breedon limestone is used in Leicester- shire, where it is called hot lime; and £ have been in- formed by farmers in the neighbourhood of the quarry, that they employ it advantageously in small quantities, seldom more than 25 or 30 bushels to the acre. And that they find it may be used with good effect in larger quantities, upon rich land. A minute chemical consideration of this question will lead to its solution. Magnesia has a much weaker attraction for carbonic acid than lime, and will remain in the state of caustic or calcined magnesia for many months, though exposed to the air. And as long as any caustic lime remains, the magnesia cannot be combined with carbonic acid, for lime instantly attracts carbonic acid from magnesia. In making some inquiries concerning this subject, I When a magnesian limestone is burni, the magnesia is deprived of carbonic acid much sooner than the lime ; and if there is not much vegetable or animal matter in the soil to supply by its decomposition carbonic acid, the magnesia will remain for a long time in the caustic state; and in this state acts as a poison to certain vege- tables. And that more magnesian lime may be used upon rich soils, seems to be owing to the circumstance, that the decomposition of the manure in them supplies carbonic acid. And magnesia in its mild state, 1. e. fully combined with carbonic acid, seems to be always a useful constituent of soils. I have thrown carbon- ate of magnesia (procured by boiling the solution of mag- nesia in super-carbonate of potassa) upon grass, and upon growing wheat and barley, so as to render the sur- face white; but the vegetation was not injured in the slightest degree. And one of the most fertile parts of Cornwall, the Lizard, is a district in which the soil con- tains mild magnesian earth. Vhe Lizard Downs bear a short and green grass, which feeds sheep producing excellent mutton; and the cultivated parts are amongst the best corn lands in the county. That the theory which I have ventured to give of the | operation of magnesian lime is not unfounded, is shewn by an experiment which I made expressly for the pur- pose of détermining the true nature of the operation of this substance. I took four portions of the same soil : with one Ll mixed <5 of its weight of caustic magnesia, with another I mixed the same quantity of magnesia and a proportion of a fat decomposing peat equal to one- fourth of the weight of the soil. One portion of soil re- mained in its natural state; and another was mixed with peat without magnesia. ‘The mixtures were made in De- cember 1806; and in April 1807, barley was sown in all of them. It grew very well in the pure soil, but bet- ter in the soil containing the magnesia and peat; and nearly as well in the soil containing peat alone: but in the soil containing the magnesia alone, it rose very feeble, and looked yellow and sickly. I repeated this experiment in the summer of 4840 with similar results; and I found that tbe magnesia in the 221 soil mixed with peat became strongly effervescent, whilst the portion in the unmixed soil gave carbonic ~ acid in much smaller quantities. In the one case the magnesia had assisted in the formation of a manure, and had become mild; in the other case it had acted as a poison. Itis obvious, from what has been said, that lime from the magnesian limestone may be applied in large quan- tities to peats ; and that where lands have been injured by the application of too large a quantity of magnesian lime, peat will be a proper and efficient remedy. IT mentioned that magnesian limestones effervesced little when plunged into an acid. A simple test of mag- nesia in a limestone is this circumstance, and its render- ing diluted nitric acid or aqua fortis milky. Frem the analysis of Mr. Tennant, it appears that the magnesian limestones contain from 20.3 to 22.5 magnesia. 29.5 to 31.7 lime. 47.2 carbonic acid. 0.8 clay and oxide of iron. Magnesian limestones are usually coloured brown or _ pale yellow. They are found in Somersetshire, Lei- cestershire, Derbyshire, Shropshire, Durham, and York- shire. I have never met with any in other counties in England; but they abound in many parts of Ireland, particularly near Belfast. The use of lime as a cement, is not a proper subject for extensive discussion in a course of Lectures on the chemistry of agriculture; yet as the theory of the opera- tion of lime in this way is not fully stated in any elemen- tary book that I have perused, I shall say a very few ’ words on the applications of this part of chemical know- ledge. T here are two modes in which lime acts as a cement; in its combination with water, and in its combination with carbonic acid. The hydrate of lime has been already mentioned. When quicklime is rapidly made into a paste with wa- ter, it soon loses its softness, and the water and the lime 222 form together a solid coherent mass, which consists, as has been stated before, of 17 parts of water to 55. parts of lime. When hydrate of lime whilst it is con- solidating, is mixed with red oxide of iron, alumina, or silica, the mixture becomes harder and more cohe- rent than when lime alone is used: and it appears that this is owing to a certain degree of chemical attraction between hydrate of lime and these bodies; and they render it less liable to decompose by the action of the carbonic acid in the air, and less soluble in water. The basis of all cements that are used for works which are to be covered with water must be formed from hydrate of lime; and the lime made from impure lime- stones answers this purpose very well. Puzzolana is composed principally of silica, alumina, and oxide of iron; and it is used mixed with lime to form cements intended to be employed under water. Mr. Smeaton, in the construction of the Eddystone lighthouse, used a cement composed of equal parts by weight of slacked lime and puzzolana. Puzzolana is a decomposed lava. Tarras, which was formerly imported in considerable quantities from Holland, is a mere decomposed basalt : two parts of slacked lime and one part of tarras forms the principal part of the mortar used in the great dykes of Holland. Substances which will answer all the ends of puzzolana and tarras are abundant in the Bri- tish islands. An excellent red tarras may be procured in any quantities from the Giant’s Causeway, in the north of Ireland: and decomposing basalt is abundant in many parts of Scotland, and in the northern districts of England in which coal is found. Parker’s cement, and cements of the same kind made at the alum works of Lord Dundas and Lord Mulgrave, are mixtures of calcined ferruginous, siliceous, and alu- minous matter, with hydrate of lime. The cements which act by combining with carbonic acid, or the common mortars, are made by mixing to- gether slacked lime and sand. These mortars, at first solidify as hydrates, and are slowly converted into car- bonate of lime by the action of the carbonic acid of the air, Mr. Tennant found that a mortar of this kind in three years and a quarter had regained 63 per cent. of ann ty S.8, Pate ¥ oh a ww) 223 the quantity of carbonic acid gas which constitutes the definite proportion in carbonate of lime. The rubbish of mortar from houses owes its power to benefit lands principally to the carbonate of lime it contains, and the - sand in it; and its state of cohesion renders it particu- larly fitted to improve clayey soils. The hardness of the mortar in very old buildings de- pends upon the perfect conversion of all its parts into carbonate of lime. The purest limestones are the best adapted for making this kind of mortar; the magnesian limestones make excellent water cements, but act with too little energy upon carbonic acid gas to make good common mortar. The Romans according to Pliny, made their best mortar a year before it was used: so that it was par- tially cembined with carbonic acid gas before it was employed. In burning lime there are some particular precautions required for the different kinds of limestones. In ge- neral, one bushel of coal is sufficient to make four or five bushels of lime. The magnesian limestone re- quires less fuel than the common limestone. In all cases in which a limestone contatning much aluminous or siliceous earth is burnt, great care should be taken to prevent the fire from becoming too intense ; for such lime easily vitrifies, in consequence of the affinity of lime for silica and alumina. And as in some places there are no other limestones than such as contain other earths, it is important to attend to this circumstance. A moderately good lime may be made at a low red heat; but it will melt into a glass at a white heat. In limekilns for burning such lime, there should be always _ adamper. In general, when limestones are not magnesian their purity will be indicated by their loss of weight in burn- ing; the more they lose, the larger is the quantity of calcareous matter they contain. ‘The magnesian lime- stones contain more carbonic acid than the common lime- stones; and I have found all of them lose more than half their weight by calcination. Besides being used in the forms of lime and carbon- ate of lime, calcareous matter is applied for the pur- poses of agriculture in other combinations. One of these oe) Se ag a . 294 bodies is gypsum or sulphate of lime. ‘This substance consists of sulphuric acid (the same body that exists combined with water in oil of vitriol) and lime; and when dry it is composed of 55 parts of lime and 75 parts of sulphuric acid. Common gypsum or selenite, such as that found at Shotover Hill, near Oxford, con- tains, besides sulphuric acid and lime, a considerable quantity of water ; and its composition may be thus ex- pressed : Sulphuric acid, one proportion - 75 Lime, one proportion - . 55 Waiter, two proportions —- - 34 The nature of gypsum is easily demonstrated ; if oil of vitriol be added to quicklime, there is a violent heat produced ; when the mixture is ignited, water is given off, and gypsum alone is the result, if the acid has been used in sufficient quantity; and gypsum mixed with quicklime, if the quantity has been deficient. Gypsum, free from water, is sometimes found in nature, when if is called anhydrous solenite. It is distinguished from common gypsum by giving off no water when heated. When gypsum, free from water, or deprived of wa- ter by heat, is made into a paste with waiter, it rapidly sets by combining with that fluid. Plaster of Paris is powdered dry gypsum, and its property as a cement, and in its use in making casts, depends upon its solidi- fying a certain quantity of water, and making with it a coherent mass. Gypsum is soluble in about 500 times its weight of cold water, and is more soluble in hot wa- — ter ; so that when water has been boiled in contact with gypsum, crystals of this substance are deposited as the water cools. Gypsum is easily distinguished by its properties of affording precipitates to solutions of oxa- lates and of barytic salts. Great difference of opinion has prevailed amongst agriculturists with respect to the uses of gypsum. It has been advantageously used in Kent, and various tes- timonies in favour of its efficacy have been laid before the Board of Agriculture of Mr. Smith. In America it is imployed with signal success; but in most coun- ties of England it has failed, though tried in various ways, and upon different crops. Very discordant notions have been formed as to the — 2 okie aye eh 5h 225 mode of operation of gypsum. It has been supposed by some persons to act by its power of attracting mois- ture from the air; but this agency must be compara- _ tively insignificant. When combined with water, it re- tains that fluid too powerfully to yield it to the roots of the plant, and its adhesive attraction for moisture is inconsiderable; the small quantity in which it is used likewise is a circumstance hostile to this idea. It has been said that gypsum assists the putrefaction of animal substances, and the decomposition of manure. I have tried some experiments on this subject which are contradictory to the notion. I mixed some minced veal with about one-one hundredth part of its weight of gyp- sum, and exposed some veal without gypsum under the same circumstances; there was no difference in the time in which they began to putrify, and the process seem- ed to me most rapid in the case in which there was no sypsum present. I made other similar mixtures, em- ploying in some cases larger, and in some cases smaller quantities of gypsum; and I used pigeons’ dung in one instance instead of flesh, and with precisely similar re- sults. it certainly in no case increased the rapidity of putrefaction. Though it is not generally known, yet a series of ex- periments has been carried on for a great length of time in this country upon the operation of gypsum as a ma- nure. The Berkshire and the Wiltshire peat-ashes con- tain a considerable portion of this substance. In the Newbury peat-ashes I have found from one-fourth to one-third of gypsum, and a: larger quantity in some peat-ashes from the neighbourhood of Stockbridge: the other constituents of these ashes are calcareous, alumi- “nous, and siliceous earth, with variable quantities of sulphate of potassa, a little common salt and sometimes fade of iron. ‘The red ashes contain most of this last substance. ; These peat-ashes are used as a top dressing for cul- ’ tivated grasses, particularly sainfoin and clover. In ex- ainining the ashes of sainfoin, clover, and rye grass, I found that they afforded considerable quantities of gyp- sum; and this substance, probably, is intimately com- bined as a necessary part of their woody fibre. Tf this Ff 226 be allowed, it is easy to explain the reason ‘whyit 0 ope- rates in such small quantities; for the whole of aclover crop, or sainfoin crop, on an acre, according to my es- timation, would afford by incineration only three or four bushels of gypsum. In examining the soil in a field near Newbury, which was taken from below a foot-path near the gate, where gypsum could not have been arti- ficialiy furnished, I could not detect any of this substance in it; and at the very time I collected the soil, the peat- ashes were applied to the clover inthe field. ‘The rea- son why gypsum is not generally efficacious, is probably because most cultivated soils contain it in sufficient quantities for the use of the grasses. In the common course of cultivation gypsum is furnished in the manure 5 for it is contained in stable dung, and in the dung of all cattle fed on grass; and it is not taken up in corn crops, or crops of peas and beans, and in very small quanti- ties in turnip crops; but where lands are exclusive- ly devoted to pasturage and hay, it will be continually consumed. I have examined four different soils culti- vated by a series of common courses of crops, for gyp- sum. One was a light sand from Norfolk; another a ‘clay, bearing a good wheat, from Middlesex ; the third — a sand, from Sussex ; the fourth a clay, from Essex. I found gypsum in all of them; and in the Middlesex soil it amounted nearly to one per cent. Lord Dundas in- forms me, that having tried gypsum without any benefit on two of his estates | in Yorkshire, he was induced to have the soil examined for gypsum, according to the process described in the Fourth Lecture, and this sub- stance was found in both the soils. Should these statements be confirmed by future i inqui- ries, a practical inference of some value may be derived from them. It is possible that lands which have ceased to bear good crops of clover, or artificial grasses, may be restored by being manured with gypsum. I have mentioned that this substance is found in Oxfordshire ; it is likewise abundant in many other parts of Eng eland; in Gloucestershire, Somersetshire, Derbyshire, York- shire, &c. and requires only pulverization for its prepa- ration. Some very interesting documents upon the use of sul- t \ CS eo ‘a . re pe . . phate of iron or green yitriol, which is a salt produced trom peat in Bedfordshire, have been laid before the Board by Dr. Pearson; and I have witnessed the fer- tilizing effects of a ferruginous water used for irrigating — a grass meadow made by the Duke of Manchester at Priestly Bog, near Woburn, an account of the produce of which has been published by the Board of Agrical- ture. I have no doubt that the peat salt and the vi- triolic water acted chiefly by producing gypsum. The soils on which both are efficacious are calcare- ous; and sulphate of iron is decomposed by the carbon- ate of lime in such soils. ‘The sulphate of iron con- sists of sulphuric acid and oxide of iron, and is an acid and a very soluble salt; when a solation of it is mixed with carbonate of lime, the sulphuric acid quits the ox- ide of iron to unite to the lime, and the compounds pro- duced are insipid and comparatively insoluble. I collected some of the decomposition from the ferrugi- - nous water on the soil in Priestley meadow. IL found it consisted of gypsum, carbonate of iron, and insoluble sulphate of iron. The principal grasses in Priestley meadow are, meadow fox-tail, cock’s foot, meadow fes- cue, fiorin, and sweet scented vernal grass. I have ex- amined the ashes of three of these grasses, meadow fox- tail, cock’s foot, and fiorin. They contained a consi- derable proportion of gypsum. . Vitriolic impregnations in soils where there is no cal- careous matter, as in a soil from Lincolnshire, to which I referred in the Fourth Lecture, are injurious; but it is probably in consequence of their supplying an excess of ferruginous matter to the sap. Oxide of iron in small quantities forms a useful part of soils; and, as is evi- dent from the details in the Third Lecture, it is found in the ashes of plants, and probably is hurtful only in its acid combinations. I have just mentioned certain peats, the ashes of which afford gypsum; but it must not be inferred from this that all peats agree with them. I have examined vari- ous peat-ashes from Scotland, Ireland, Wales, and the northern and western parts of England, ‘which contain- ed no quantity that could be useful; and these ashes 2 228, abounded in silicious, aluminous earths, and oxide of iron. Lord Charleville found in some peat-ashes from The land sulphate of potassa, i. e. the sulphuric acid combi- ned with potassa. Vitriolic matter is usually formed in peats 5 and if the soil or substratum is calcareous, the ultimate result is the production of gypsum. In general, when a recent foi ash emits a strong smell resembling that of rotten eges when acted upon “by vinegar, it will furnish gyp- sum. Phosphate of lime is a combination of phosphoric acid and lime, one proportion of each. It is a compound in- soluble in pure water, but soluble in water containing any acid matter. It forms the greatest part of calcined bones. It exists in most excrementitious substances, and is found both in the straw and grain of wheat, bar- ley, oats, and rye, and likewise in beans, peas and tares. It exists in some places in these islands native, but only in very small quantities. Phosphate of lime is generally conveyed to the land in the composition of other manure, and it is probably necessary to corn crops and other white crops. Bone ashes ground to powder will probably be found useful on arable lands containing much vegetable mat- ter, and may perhaps enable “soft peats. to produce wheat; but the powdered bone in an uncalcined state is much to be preferred in all cases when it can be pro- cured. The saline compounds of magnesia will require very little discussion as to their uses as manures. ‘The most important relations of this subject to agriculture have been considered in the former part of this Lecture, when the application of the magnesian limestone was exam- ined. In combination with sulphuric acid magnesia forms a soluble salt, This substance, it is stated by some inquirers, has been found of use asa manure; but it is not found in nature in sufficient abundance, nor is it capable of being made artificially sufficiently cheap to be of useful application in the common course of hus- bandry. 4 y 229° Wood ashes consist principally of the vegetable alkali united to carbonic acid ; and as this alkali is found in al- most all plants, it is not difficult to conceive that it may form an essential part of their organs. The general _tendency of the alkalies is to give solubility to vegetable matters; and in this way they may render carbonace- ous and other substances capable of being taken up by the tubes in the radical fibres of plants. The vegeta- ble alkali likewise has a strong attraction for water, and even in small quantities may tend to give a due de- sree of moisture to the soil, or to other manures; though this operation from the small quantities used, or exist- ing in the soil, can be only of a secondary kind. The mineral alkali, or soda, is found in the ashes of sea-weed, and may be procured by certain chemical agencies from common salt. Common salt consists of the metal named sodium, combined with chlorine ; and pure soda consists of the same metal united to oxy- gene. When water is present, which can afford oxy- gene to the sodium, soda may be obtained in several modes from salt. The same reasoning will apply to the operation of the pure mineral alkali, or the carbonated alkali, as to that of the vegetable alkali; and when common salts acts as @ manure, it is probably by entering into the composition of the plant in the same manner as gypsum, phosphate of lime, and the alkalies. Sir John Pringle has stated, that salt in small quantities assists the de- composition of animal and vegetable matter. This cir- cumstance may render it useful in certain soils. Com- mon salt likewise is offensive to insects.—That in small quantities it is sometimes a useful manure, I believe it fully proved; and it is probable that its efficacy depends upon many combined causes. Some persons have argued against the employment of salt; because when used in large quantities, it either does uo good, or renders the ground sterile; but this is a very unfair mode of reasoning. That salt in large quantities rendered lands barren, was known long be- fore any records of agricultural science existed. We read in the Scriptures, that Abimelech took the city of Shechem, “ and beat down the city and sowed it with pe) 4 gil reprobates a salt soil; and Pliny, though he recom: , mends giving salt to cattle, yet affirms, that when strew- ‘ed over land it renders it barren. But these are not ar- guments against a proper application of it. Refuse salt in Cornwall, which, however, likewise contains some of the oil and exuview' of fish, has long been known as an admirable manure. And the Cheshire farmers con- tend for the benefit of the peculiar. produce’ of their: country. . It is not unlikely, that the same causes influence the effects of salt, as those which act in modifying the ope- ration of gypsum. Most lands in this island, particu- larly those near the sea, probably contain a sufficient quantity of salt for all the purposes of vegetation ; and in such cases the supply of it to the soil will not only be useless, but may be injurious. In great storms the spray of the sea has been carried more than 50 miles from the shore; so that from this source salt must be often supplied to the soil. I have found salt in all the sandstone rocks that I have examined, and it must ex- ist in the soil derived from these rocks. Itis a constitu- ent likewise of almost every kind of animal and vegeta- ble manure. Besides these compounds of the alkaline earths and alkalies, many others have been recommended for the purposes of increasing vegetation; such are nitre, or the nitrous acid combined with potassa. Sir Kenelm Digby states, that he made barley grow very luxuriantly by watering it with a very weak solution of nitre; but he is to speculative a writer to awaken confidence in his results. ‘This substance consists of one proportion of azote, six of oxygene, and one of potassium; and it is not unlikely that it may furnish azote to form albumen, or gluten, in those plants that contain them; but the nitrous salts are too valuable for other purposes to be used as manures. Dr. Home. states, that sulphate of potassa, which as 1 just now mentioned, is found in the ashes of some peats, is a useful manure. But Mr. Naismith* ques- * Elements of Agriculture, p. 78. i galt;?? that the soil might be for ever untruitfu \M Wir- : 231 rae tions his results ; and quotes experimenis hostile to his opinion, and, as he conceives, unfavourable to he effi- cacy of any species of saline manure. Much of the discordance of the evidence relating: to ‘the efficacy of saline substances depends upon the cir- cumstance of their having been used in different pro- portions, and in general, in quantities much too large. I made a number of experiments in May and June, 4807, on the effects of different saline substances on bar- ley and on grass growing in the same garden, the soil of which was a light sand, of which 100 parts were composed of 60 parts of siliceous sand, and 24 parts finely divided matter, consisting of seven parts carbon- ate of lime, 12 parts alumina and silica, less than one part saline matter, principally common salt, with a irace of gypsum and sulphate of magnesia: the remain- ing 16 parts were vegetable matter. The solutions of “the saline substances were used twice a week, in the quantity of two ounces, on spots of grass and corn, sufficiently remote from each other to prevent any interference of results. U'he substances tried were super-carbonate, sulphate, acetate, nitrate, -and muriate of potassa; sulphate of soda, sulphate, nitrate, muriate, and carbonate of ammonia. 1 found, that in all cases when the quantity of the salt equalled one-thirtieth part of the weight of the water, the effects Were injurious ; but least so in the instances of the car- bonate, sulphate and muriate of ammonia. When the quantities of the salts were one-three hundredth part of the solution the effects were different. The plants wa- tered with the solutions of the sulphates grew just in the same manner as similar plants watered with rain water. ‘Those acted on by the solution of nitre, acetate, and super-carbonate of potassa, and muriate of ammo- nia, grew rather better. ‘Those treated with the solu- tion of carbonate of ammonia grew most luxuriantly of all. This last result is what might be expected, for carbonate of ammonia cousists of carbon, hydrogene, azote, and oxygene. ‘l'here was, however, another re. sult which I had not anticipated; the plants watered with solution of nitrate of ammonia did not grow better than those watered with rain water. ‘The : solution red- Myditie ait \ Wait wine, AN | 232 3 ‘ dened litmus paper; and probably the free acid ex- erted a prejudicial effect, and interfered with the re- sult. Soot doubtless owes part of its efficacy to the ammo- niacal salt that it contains. ‘The liquor produced by the distillation of coal contains carbonate and acetate of am- monia, and is said to be a very good manure. In 1808, I found the growth of wheat in a field at Roehampton assisted by a very weak solution of acetate of ammonia. Soapers’ waste has been recommended as a manure, and it has been supposed that its efficacy depended upon the different saline matters it contains ; but their quan- tity is very minute indeed, and its principal ingredients are mild lime and quicklime. In the soapers’ waste from the best manufactories, there is scarcely a trace of alkali. Lime moistened with sea water affords more of this substance, and is said to have been used in some cases with more benefit than common lime. It is unnecessary to discuss to any greater extent the effects of saline substances on vegetation; except the ammoniacal compounds, or the compounds containing nitric, acetic, and carbonic acid; none of them can af- > ford by their decomposition any of the common princi- ples of vegetation, carbon, hydrogene, and oxygene. The alkaline sulphates and the earthy muriates are so seldom found in plants, or are found in such minute quantities, that it can never be an object to apply them to the soil. It was stated in the beginning of this Lec- ture, that the earthy and alkaline substances seem ne- ver to be formed in vegetation ; and there is every rea- son, likewise, to believe, that they are never decompo- sed 5; for after being absorbed they are found in their ashes. The metallic bases of them cannot exist in contact with aqueous fluids ; and these metallic bases, like other metals, have not as yet been resolved into any other forms of matter by artificial processes; they combine readily with other elements; but they remain undes- tructible, and can be traced undiminished in quantity, through their diversified combinations. / LECTURE VIIt. - On the Improvement of Lands by Burning ; chemical Principles of this Operation. On Irrigation and its Effects. On Fallowing ; its Disadvantages and Uses. On the convertible Husbandry founded on re- gular Rotations of different Crops. On Pasture ; Views connected with its Application. On various Agricultural Objects connected with Chemistry. Con- clusion. Tue Heravement of sterile lands by burning, was known to the Romans. It is mentioned by Virgil in the first book of the Georgics: “ Sepe etiam steriles incendere profuitagros.”’ [tis a practice still much in use in many parts of these Islands; the theory of its opera- tion has-occasioned much discussion, both amongst sci- entific men and farmers. It rests entirely upon chemi- cal doctrines; and I trust [ shall be able to offer you satisfactory elucidations on the subject. _ The basis of all common soils as f stated in the Fourth Lecture, are mixtures of the primitive earths and oxide of iron; and these earths have a certain degree of at- traction for each other. ‘To regard this attraction’ in its) “proper point of view, it is only necessary to consider the composition of any common siliceous stone. Feldspar, for instance, contains sjliceous, aluminous, calcareous earths, fixed alkali, and oxide of iron, which exist in one compound, in consequence of their chemical attrac- tions for cach other. Let this stone be ground into im- palpable powder, it then becomes a substance like clay: if the powder be heated very strongly it fuses, and on cooling forms a coherent mass similar to the original stone; the parts separated by mechanical division ad- here again in consequence of chemical attraction. If the powder is heated less strongly the particles only su- perficially combine with each other, and form a gritty. Gs OM ‘ } nuit 234 mass, which, when broken into pieces, has the charac- ters of sand. oe If the power of the powdered feldspar to absorb wa- ter from the atmosphere before, and after the applica- tion of the heat, be compared, it is found much less in the last case. The same effect takes place when the powder of other siliceous or aluminous stones is made the subject of ex- periment. I found that two equal portions of basalt ground into impalpable powder, of which one had been strongly ig- nited, and the other exposed only to a temperature equal to that of boiling water, gained very different weights in the same time when exposed to air. In four hours the one had gained only two grains, whilst the other had gained seven grains. When clay or tenacious soils are burnt, the effect is of the same kind ; they are brought nearer to a state analogous to that of ‘sands. In the manufacture of bricks the general principle is well illustrated ; if a piece of dry brick earth be appli- ed to the tongue it will adhere to it very strongly, in consequence of its power to absorb water; but after it has been burnt there will be scarcely a sensible adhe- sion. The process of burning renders the soil less com- pact, less tenacious and retentive of moisture; and ” when properly applied, may convert a matter that was stiff, damp, and in consequence cold, into one pow- dery, dry, and warm; and much more proper as a bed for vegetable life. The great objection made by speculative chemists to paring and burning, is, that it destroys vegetable and animal matter, or the manure in the soil ; buts in cases in which the texture of its earthy ingredients is perma- nently improved, there is more than a compensation for this temporary disadvantage. And in some soils where there is an excess of inert vegetable matter, the de- struction of it must be beneficial; and the carbonace- ous matter remaining in the ashes may be more useful to the crop than the vegetable fibre, from which it was produced. 235 IT have examined by a chemical analysis three spe- cimens of ashes from different lands that had under-. gone paring and burning. ‘I'be first was a quantity sent _ to the Board by M. Boys of Bellhanger, in Kent, whose treatise on paring and burning has been pub- lished. They were from a chalk soil, and 200 grains contained 80 Carbonate of lime. 14 Gypsum. 4 9 Charcoal 45 Oxide of iron. 3 Saline matter. Sulphate of potash. Muriate of magnesia, witha minute quan- tity of vegetable alkali. The remainder alumina and silica, Mr. Boys estimates that 2660 bushels are the com- mon produce of an acre of ground, which, according to his calculation would give 172900 lbs. containing Carbonate of lime 69160 lbs. Gypsum - - 9509.5 Oxide of iron 42967.5 Saline matter - 2593.5 Charcoal - - 7780.5 In this instance there was undoubtedly a very consi- derable quantity of matter capable of being active as manure produced in the operation of burning. The charcoal was very finely divided; and exposed on a large surface on the field, must have been gradually converted into carbonic acid. And gypsum and oxide of iron, as I mentioned in the last Lecture, seem to produce the very best effects when applied to lands con- taining an excess of carbonate of lime. The second specimen was from a soil near Coleor- ton, in Leicestershire, containing only four per cent. of | carbonate of lime, and cotisisting of three-fourths light siliceous sand, and about one-fourth clay. This had 236 * been turf patute! burning, and 100 parts of th ashes ee ave. "gs al 6 parts charcoal 3 Muriate of soda and sulphate of pouen, with a trace of vegetable alkali. 9 Oxide of iron, And the remainder the earths. In this instance, as in the other, finely divided char- coal was found; the solubility of which would be in- creased by the presence of the alkali. The third instance was, that of a stiff clay, from Mount’s Bay, Cornwall. This land had been brought into cultivation from a heath by burning about ten years before ; but having been neglected, furze was spring- ing up in different parts of it, which gave rise to the se- cond paring and burning. 100 parts of the ashes con- tained 8 parts of charcoal. 2 of saline matter principally common salt, with a little vegetable alkali. 7 Oxide of iron. 2 Carbonate of lime. Remainder alumina and silica. Here the quantity of charcoal was greater than in the other instances. ‘The salt, | suspect, was owing to the vicinity of the sea, it being but two miles off. In this land there was certainly an excess of dead vegeta- ble fibre, as well as an unprofitable living vegetable matter; and I have since heard that a great improve- ment took place. | Many obscure causes have been referred to for the purpose of explaining the effects of paring and burning; but I believe they may be referred entirely to the dimi- nution of the coherence and tenacity of clays, and to the destruction of inert, and useless vegetable matter, and its conversion into a manure. Dr. Darwin, in his Phytologia, has supposed, that _ Or Ai ‘ ‘1 a clay during torrefaction, may absorb some nutritive prin- ciples from the atmosphere that afterwards may be sup- plied to plants ; but the earths are pure metallic oxides, _ saturated with oxygene; and the tendency of burning is — _ to expel any other volatile principles that they may con- tain in combination. If the oxide of iron in soils is not saturated with oxygene, torrefaction tends to produce its further union with this principle; and hence in burn- ing, the colour of clays changes to red. The oxide of iron containing its full proportion of oxygene has less attraction for acids than the other oxide, and is conse- quently less likely to be dissolved by any fluid acids in the soil; and it appears in this state to act in the same manner as the earths. A very ingenious author, whom I quoted at the end of the last Lecture, supposes that the oxide of iron when combined with carbonic acid is poisonous to plants; and that one use of torrefaction is to expel: the carbonic acid from it; but the carbonate of iron is not soluble in water, and is a very inert substance; and I have raised a luxuriant crop of cresses in a soil composed of one-fifth carbonate of iron, and four-fifths carbonate of lime. Carbonate of iron abounds in some of the most fertile soils in England, particularly the red hop soil. And there is no theoretical ground for sup- posing, that carbonic acid, which is an essential food of plants, should in any of its combinations be poisonous to, them; and it is known that lime and magnesia are both noxious to vegetation, unless combined with this principle. All soils that contain too much dead. vegetable fibre, and which consequently lose from one-third to one-half of their weight by incineration, and all such as contain their earthy constituents in an impalpable state of divi-. sion, i. e. the stiff clays and marles, are improved by burning; but in coarse sands, or rich soils containing a just mixture of the earths; and in all cases in which the texture is already sufficiently loose, or the organizable matter sufficiently soluble, the process of torrefaction cannot be useful. All poor siliceous sands must be injured by it; and here practice is found to accord with theory. Mr. Young, in his Essay on Manures, states, “ that he found ! 238 & burning injure sand ;”’ and the operation is never per- formed by good agriculturists upon siliceous sandy _ Soils, after they have once been brought into cultiva- ~ tion. An intelligent farmer in Mount’s Bay told me, that he had pared and burned a small field several years ago, which he had not been able to bring again into good con- dition. I examined the spot, the grass was very poor and scanty, and the soil an arid siliceous sand. Irrigation or watering land, is a practice, which at first view appears the reverse of torrefaction ; and in ge- neral, in nature the operation of water is to bring earthy substances into an extreme state of division. Butin the artificial watering of meadows, the beneficial effects de- pend upon many different causes, some chemical, some mechanical. Water is absolutely essential to vegetation; and when land has been covered with water in the winter, or in _ the beginning of spring, the moisture that has penetra- ted deep into the soil, and even the subsoil, becomes a source of nourishment to the roots of the plant in the summer, and prevents those bad effects that often hap- pen in lands in their natural state, from a long continu- ance of dry weather. When the water used in irrigation has flowed over a calcareous country, it is generally found impregnated with carbonate of lime; and in this state it tends, in many instances, to ameliorate the soil. Common river water also generally contains a certain portion of organizable matter, which is much greater after rains, than at other times; and which exists in the largest quantity when the stream rises in a cultiva- ted country. Eyen in cases when the water used for flooding is pure and free from animal or vegetable substances, it acts by causing the more equable diffusion of nutritive matter existing in the land ; and in very cold seasons it preserves the tender roots and leaves of the grass from being affected by frost. Waiter is of greater specific gravity at 42° Fahren- heit, than at 32°, the freezing point; and hence in a - meadow irrigated in winter, the water immediately in ite, Meee, 4 A PEE | Pane ’ by Bie! one 939 Ww contact with the grass is rarely below 40°; a degree of — temperature not at all prejudicial to the living organs of |” plants. 5 in 1804, in the month of March, lexamined thetem- perature in a water meadow near Hungerford, in Berk-_ shire, by a very delicate thermometer. The tempera- ture of the air at seven in the morning was 29°. The water was frozen above the grass. The temperature of the soil below the water in which the roots of the grass were fixed, was 43°. In general those waters which breed the best fish are the best fitted for watering meadows; but most of the benefits of irrigation may be derived from any kind of water. It is, however, a general principle, that waters containing ferruginous impregnations, though possess- ed of fertilizing effects, when applied to a calcareous soil, are injurious on soils that do not effervesce with acids; and that calcareous waters which are known by the earthy deposit they afford when boiled, are of most use on siliceous soils, or other soils containing no re- markable quantity of carbonate of lime. The most important processes for improving land, are those which have been already discussed, and that are founded upon the circumstance of removing certain con- stituents from the soil, or adding others or changing their nature; but there is an operation of very ancient practice still much employed, in which the soil is expo- sed to the air, and submitted to processes which are purely mechanical, namely, fallowing. The benefits arising from fallows have been much over-rated. A summer fallow, or a clean fallow, may be sometimes necessary in lands overgrown with weeds, particularly if they are sands which cannot be pared and burnt with advantage; but is certainly unprofitable as part of a general system in husbandry. It has been supposed by some writers, that certain principles necessary to fertility are derived from the at- mosphere, which are exhausted by a succession of crops, and that these are again supplied during the repose of the land, and the exposure of the pulverized soil to the influence of the air; but this in truth is not the case. The earths commonly found in soils cannot be combined it / , eA aty ne 240. with more oxygene ; none of them unite to azote; and such of them as are capable of attracting carbonic acid, are always saturated with it in those soils on which the practice of fallowing is adopted. The vague ancient opinion of the use of nitre, and of nitrous salts in ve- getation, seems to have been one of the principal spe- culative reasons for the defence of summer fallows. Nitrous salts are produced during the exposure of soils containing vegetable and animal remains, and in greatest abundance in hot weather; but it is probably by the combination of azote from these remains with oxygene in the atmosphere that the acid is formed; and at the expense of an element, which otherwise would have formed ammonia; the compounds of which, as is evi- dent from what was stated in the last Lecture, are much more efficacious than the nitrous compounds in assisting vegetation. When weeds are buried in the soil, by their gradual decomposition they furnish a certain quantity of soluble matter; but it may be doubted whether there is as much useful manure in the land at the end of a clean fallow, as at the time the vegetables clothing the sur- face were first ploughed in. Carbonic acid gas is form- ed during the whole time by the action of the vegeta- ble matter upon the oxygene of the air, and the greater part of it is lost te the soil in which it was formed, and dissipated in the atmosphere. The action of the sun upon the surface of the soil tends to disengage the gaseous and the volatile fluid matters that it contains ; and heat increases the rapidity of fermentation: and in the summer fallow, nourish- ment is rapidly produced, at a time when no vegetables” are present capable of absorbing it. Land, when it is not employed in preparing food for animals, should be applied to the purpose of the pre- paration of manure for plants; and this is effected by means of green crops, in consequence of the absorption of carbonaceous matter in the carbonic acid of the at- mosphere. In a summer’s fallow a period is always lost in which vegetables may be raised, either as food for animals, or as nourishment for the next crop; and the texture of the soil is not so much improved by ils Bi Wiha, 241 exposure as in winter, when the expansive powers of ice, the gradual dissolution of snows, and the alterna- tions from wet to dry, tend to pulverize it, and to mix its different parts together. In the drill husbandry the land is preserved clean by the extirpation of the weeds by hand, and by raising the crops in rows, which renders the destruction of the weeds much more easy. Manure is supplied either by the green crops themselves, or from the dung of the cat- tle fed upon them; and the plants having large sys- tems of leaves, are made to alternate with those bear- ing grain. It is a great advantage in the convertible system of cultivation, that the whole of the manure is employed ; and that those parts of it which are not fitted for one crop, remain as nourishment for another. Thus, in Mr. Coke’s course of crops, the turnip is the first in the or- der of succession ; and this crop is manured with recent dung, which immediately affords sufficient soluble mat- ter for its nourishment; and the heat produced in fer- mentation assists the germination of the seed and the growth of the plant. After turnips, barley with grass seeds is sown; and the land having been little exhaust- ed by the turnip crop, affords the soluble parts of the — decomposing manure to the grain. The grasses, rye grass, and clover remain, which derive a small part only of their organized matter from the soil, and proba- bly consume the gypsum in the manure which would be useless to other crops: these plants likewise by their large systems of leaves, absorb a considerable quantity of nourishment from the atmosphere; and when plough- ed in at the end of two years, the decay of their roots: and leaves affords manure for the wheat crop; and at this period of the course, the woody fibre of the farm- yard manure which contains the phosphate of lime and the other difficultly soluble parts, is broken down ; and. as soon as the most exhausting crop is taken, recent ma- nure is again applied. Mr. Gregg, :whose very enlightened system of culti- vation has been published by the Board of Agriculture, and who has the merit of first adopting a plan similar to Mr. Coke’s upon strong clays, suffers the ground af- ub ab aa gba s) 242 ter barley to remain at rest for two years in grass; sows’ — ; peas and beans on the leys; ploughs in the pea ¢ bean — ‘stubble for wheat; and in some instances, follows his wheat crops by acourse of winter tares and winter bar- - ley, which is eat off in the spring, before the land is sowed for turnips. Peas and beans, in all instances, seem well adapted | to prepare the ground for wheat; and in some rich lands, as in the alluvial soil of the Parret, mentioned in the Fourth Lecture, and at the foot of the South Downs in Sussex, they are raised in alternate crops for years together. Peas and beans contain, as appears from the analysis in the Third Lecture, a small quan- tity of a matter analogous to albumen; but it seems that the azote which forms a constituent part of this matter, is derived from the atmosphere. The dry bean leaf, when burnt, yields a smell approaching to that of de- composing animal matter; and in its decay in the soil, may furnish principles capable of becoming a part of the gluten in wheat. ‘Though the general composition of plants is very an- alogous, yet the specific difference in the products of many of them, and the facts stated in the last Lecture, prove that they must derive different materials from the soil; and though the vegetables having the smallest systems of leaves will proportionably most exhaust the soil of common nutritive matter, yet particular vegeta- bles when their produce is carried off, will require pe- culiar principles to be supplied to the land i in which they grow. Strawberries and potatoes at first produce lux- uriantly i in virgin mould, recently turned up from pas- tufe; but in a few years they degenerate, and require a fresh soil; and the organization of these plants is such, as to be constantly producing the migration of their lay- ers : thus the strawberry, by its long sheots, is constant- ly endeavouring to occupy a new soil; and the fibrous. radicles of the potato produce bulbs at a considerable distance from the parent plant. Lands, im a course of years, often cease to aflord good cultivated grasses 5 they become (as it is popularly said) tired of them; and one of the probable reasons for this was stated im the last Lecture. | i \ 245 ~The most remarkable instance of the powers of ve- ae to exhaust the soil of certain principles neces- sary to their growth is found in certain funguses. Mush- rooms are said never to rise in two successive seasons on the same spot; and the production of the phenome- na called fairy rings has been ascribed by Dr. Wollas- ton to the power of the peculiar fungus which forms it, to exhaust the soil of the nutriment necessary for the growth of the species. ‘The consequence is, that the ring annually extends; for no seeds will grow where their parents grew before them ; and the interior part of the circle has been exhausted by preceding crops; but where the fungus has died, nourishment is supplied for srass, which usually rises within the circle, coarse, and -of a dark green colour. When cattle are fed upon land not benefited by their manure, the effect is always an exhaustion of the soil ; this is particularly the case where carrying horses are kept on estates; they consume the pasture during the night, and drop the greatest part of their manure in the day during their labour in the daytime. The exportation of grain from a country, unless some articles capable of becoming manure are introduced in compensation, must ultimately tend to exhaust the soil. Some of the spots, now desart sands in northern Afri- ca, and Asia Minor, were anciently fertile. Sicily was the granary of Italy ; and the quantity of corn carried off from it by the Romans, is probably a chief cause of its present sterility. In this island, our commercial system at present has the effect of affording substances, which in their use and decomposition must enrich the land. Corn, sugar, tallow, oil, skins, furs, wine, silk, cotton, &c. are imported, and fish are supplied from the sea. Amongst our numerous exports woollen, and linen, and leather goods, are almost the only substances which contain any nutritive materials derived from the soil. In all courses of crops it is necessary that every part of the soil should be made as useful as possible to the different plants ; but the depth of the furrow in plous rh- ing must depend apon the nature of the soil, and of the > 244, subsoil. In rich clayey soils the furrow can scarcely be too deep; and even in sands, unless the subsoil’con- tains some principles noxious to vegetables, the same practice should be adopted. When the roots are deep, they are less liable to be injured, either by excess of rain, or drought; the layers shoot forth their radicles into every part of the soil; and the space from which the nourishment is derived is more considerable, than when the seed is superficially inserted in the soil. There has been much difference of opinion with re- spect to permanent pasture; but the advantages or dis- advantages can only be reasoned upon according to the circumstances of situation and climate. Under the cir- cumstances of irrigation, lands are extremely produc- tive, with comparatively little labour; and in climates where great quantities of rain falls, the natural irriga- tion produces the same effects as artificial. When hay is in great demand, as sometimes happens in the neigh- bourhood of the metropolis, where manure can be easily procured, the application of it to pasture is repaid for by the increase of crop; but top-dressing grass land with animal or vegetable manure, cannot be recommend- ed as a general system. Dr. Coventry very justly ob- serves, that there is a greater waste of the manure in this case, than when it is ploughed into the soil for seed crops. The loss by exposure to the air, and the sun- shine, offer reasons in addition to those that have been already quoted in the Sixth Lecture, for the application of manure even in this case, in a state of incipient, and not completed fermentation. Very little attention has been paid to the nature of the grasses best adapted for permanent pasture. The chief circumstance which gives value to a grass,-is the quantity of nutritive matter that the whole crop will af- ford ; but the time and duration of its produce are like- wise points of great importance; and a grass that sup- plies green nutriment throughout the whole of the year, may be more valuable than a grass which yields its pro- _ duce only in summer, though the whole quantity of food - supplied by it should be much less. The grasses that propagate themselves by layers, the = i all a arth 245 different species of Agrostis, supply pasiure throughout the year; and, as it has been mentioned on a former occasion, the concrete sap stored up in their joints, ren- ders them a good food even in winter. IL saw four square yards of fiorin grass cut in the end of January, this year, in a meadow exclusively appropriated to the cultivation of fiorin, by the Countess of Hardwicke, the soil of which is a damp stiff clay. ‘They afforded 28 pounds of fodder; of which 1000 parts afforded, 64 parts of nutritive matter, consisting nearly of one-sixth of sugar, and five-sixths of mucilage, with a little extractive mat- ter. In another experiment, four square yards gave 27 pounds of grass. he quality of this grass is inferior to that of the fiorin referred to in the Table, in the lat- ter part of the Third Lecture, which was cultivated by Sir Joseph Banks in Middlesex, in a much richer soil, and cut in December. The fiorin grass, to be in perfection, requires a moist climate or a wet soil, and it grows luxariantly in cold clays unfitted for other grasses. In light sands, and in dry situations, its produce is much inferior as to quan- tity and quality. The common grasses, properly so called, that afford most nutritive matter in early spring, are the vernal mea- dow grass, and meadow fox-tail grass; but their pro- duce at the time of flowering and ripening the seed are inferior to that of a great number of other grasses; their latter-math, is, however, abundant. Tall fescue grass stands highest, according to the ex- periments of the Duke of Bedford, of any grass, proper- ly so called, as to the quantity of nutritive matter afford- ed by the whole crop when cut at the time of flowering ; and meadow cat’s-tail grass affords most food when cut at the time the seed is ripe; the highest latter-math pro- duce of the grasses examined in the Duke of Bedford’s experiments is from the sea meadow grass. Nature has provided in all permanent pastures a mix- ture of various grasses, the produce of which differs at different seasons. Where pastures are to be made ar- tificially, such a mixture ought to be imitated; and, per- haps, pastures superior to the natural ones may be made 246. by selecting due proportions of those species of grasses fitted for the soil, which afford respectively the greatest quantities of spring, summer, latter-math, and winter produce ; areference to the details in the Appendix will shew that such a plan of cultivation is very practica- ble. In all lands, whether arable or pasture, weeds of every description should be rooted out before the seed is ripe ; and if they are suffered to remain in hedge rows, they should be cut when in flower, or before, and made into heaps for manure; in this case they will furnish more nutritive matter in their decomposition; and their in- crease by the dispersion of seeds will be prevented. The farmer, who suffers weeds to remain till their ripe seeds are shed, and scattered by the winds, is not only hostile to his own interests, but is likewise an enemy to the public: a few thistles neglected will soon stock a farm ; and by the light down which is attached to their seeds, they may be distributed over a whole country. Nature has provided such ample resources for the con- tinuance of even the meanest vegetable tribes, that it is very difficult to ensure the destruction of such as are hostile to the agriculturist, even with every precaution. Seeds excluded from the air, will remain for years in- active in the soil,* and yet germinate under favourable. circumstances; and the different plants, the seeds of which, like those of the thistle and dandelion, are fur- nished with beards or wings, may be brought from an immense distance. The fleabane of Canada has only lately been found in Europe; and Linnzus supposes -that it has been transported from America, by the very light downy plumes with which the seed is provided. * The appearance of seeds in places where their parent plantsare not found may be easily accounted for from this circumstance and other circumstances. Many seeds are carried from island to island by cur- rents in the sea, and are defended by their hard coats from the im- mediate action of the water. West Indian seeds (of this description) are often found on our coasts, and readily germinate: their ps voy- age having been barely sufficient to afford the cotyledon its die pro- portion of moisture. Other seeds are carried indigested in the sto- mach of birds, and supplied with food at the moment of their depo- sition, The light seeds of the mosses and lichens probably float in every part of the atmosphere, and abound on the surface of the sea. 247 _ ain feeding cattle with green food, there are many ad- vantages in soiling, or supplying them with food, where their manure is preserved, out of the field; the plants are less injured when cut, than when torn or jagged by the teeth of the cattle, and no food is wasted by being trodden down. They are likewise obliged to feed with- out making selection; and in consequence the whole food is consumed: the attachment, or dislike to a par- ticular kind of food exhibited by animals, offers no proof of its nutritive powers. Cattle at first refuse linseed cake, one of the most nutritive substances on which they can be fed.* * For the following observations on the selection of different kinds of common food by sheep and cattle I am obliged to Mr. George Sinclair. “ Lolium perenne, rye grass. Sheep eat this grass when it is in the early stage of its growth, in preference to most others; but af- ter the seed approaches towards perfection, they leave it for almost any other kind. A field in the Park at Woburn was laid down in two equal parts, one part with rye grass and white clover, and the other part with cock’s-foot and red clover : from the spring till mid- summer the sheep kept almost constantly on the rye grass; but after that time>they left it, and adhered with equal constancy to the cock’s- foot during the remainder of the season. Dactylis glomerata, cock’s-foot. Oxen, horses, and sheep, eat this grass readily. The oxen continue to eat the straws and flowers from the time of flowering till the time of perfecting the seed; this was exemplified in a striking manner in the field before alluded to. The oxen generally kept to the cock’s-foot and red clover, and the sheep. to the rye-grass and white clover. In the experiments published in the Ameenitates Academicz, by the pupils of Linnzus, it is asserted that this grass is rejected by oxen; the above fact, however, is in _ contradiction of it. Alopecurus pratensis, meadow fox-tail. Sheep and horses seem to have a greater relish for this grass than oxen. It delights ina soil of intermediate quality as to moisture or dryness, and is very produc- tive. In the water-meadow at Priestley, it constitutes a considerabic part of the produce of that excellent meadow. It there keeps inva- riably possession of the top of the ridges, extending generally about six feet from each side of the watercourse ; the space below that, to where the ridge ends, is stocked with cock’s foot, rough stalked mea- dow grass, Festuca pratensis, Festuca duriuscula, Agrostis stolonife- va Agrostis falustris, and sweet-scented vernal grass, with a small admixture of some other kinds. Phleum pratense, meadow cat’s-tail. This grass is eaten withous reserve, by oxen, sheep, and horses. Dr. Pulteney says, that it is dis- liked by sheep; but in pastures where it abounds, it does not appear to be rejected by these animals; but eaten in common with such When food artificially composed is to be gi en tore cattle, it should be brought as nearly as possible to the state of natural food. ‘Thus, when sugar is given to others as are growing with it. Hares are remarkably fond of it. The Phieum nodosum, Phleum alpinum, Poa fertilis, and Poa compressa, were left untouched, although they were closely adjoining to it. It seems to attain the greatest perfection in a deep rich loam. Agrostis stolonifera, fiorin. In the Experiments detailed in the Ameenitates Academicz, it is said, that horses, sheep, and oxen, eat this grass readily. On the Duke of Bedford’s farm at Maulden, fio- rin hay was placed in the racks before horses in small distinct quan- tities ; alternately with common hay ; but no decided preference for either was manifested by the horses in this trial. But that cows and horses prefer it to hay, when in a green state, seems fully proved by Dr. Richardson, in his several publications on Fiorin ; and of its pro- ductive powers in England (which has been doubted by some,) there are satisfactory proofs. Lady Hardwicke has given an account of a trial of this grass, wherein twenty-three milch cows, and one young horse, besides a number of pigs, were kept a fortnight on the pro- duce of one acre. Poa trivialis, rough-stalked meadow. Oxen, horses, and sheep, eat this grass with avidity. Hares also eat it; but they give a de- cided preference to the smooth-stalked meadow-grass, to which it is, in many respects nearly allied. Poa pratensis, smooth-stalked meadow grass. Oxen and horses are observed to eat this grass in common with others; but sheep rather prefer the hard fescue, and sheeps’ fescue, which affect a si- milar soil. This species exhausts the soil in a greater degree than almost any other species of grass; the roots being numerous, and powerfully creeping, become in two or three years completely matted together; the produce diminishes as this takes place. It grows common in some meadows, dry banks, and even on walls. Cynosurus cristatus, crested dog’s-tail grass. The South Down sheep, and deer, appear to be remarkably fond of this grass: in some parts of Woburn Park this grass forms the principal part of the herbage on which these animals chiefly browse: while another part of the Park, that contains the Agrostis capilaris, Agrostis, fiu- milis, Festuca ovina, Festuca duriuscula, and Festuca cambrica, is seldom touched by them; but the Welch breed of sheep almost constantly browse upon these, and neglect the Cynosurus cristatus, Lolium perenne, and Poa trivialis. Agrostis vulgaris (capillaris, Linn.,) fine bent; common bent. This is a very common grass on all poor dry sandy soils. It is not palatable to cattle, as they never eat it readily, if any other kinds be within their reach. The Welch sheep, however, prefer it as ] be- fore observed ; and it is singular, that those sheep being bred in the park, when some of the best grasses are equally within their reach, should still prefer those grasses which naturally grow on the Welch mountains ; it seems to argue that such a preference is the effect of some other cause, than that of habit. Festuca ovina, sheeps’ fescue. All kinds of cattle relish this — 249 them, some dry fibrous matter should be mixed with it, such as chopped straw, or dry withered grass, in order that the functions of the stomach and bowels may be grass ; but it appears from the trial that has been made with it on clayey soils, that it continues but a short tiie in possession of such, being soon overpowered by the most luxuriant kinds. On dey shal- low soils that are incapable of producing the larger sorts, this should form the principal crop, or rather the whole; for it is seldom or never, in its natural state, found intimately mixed with others; but by itself. Festuca duriuscula, hard fescue grass. . This is certainly one of the best of the dwarf sorts of grasses. It is grateful to all kinds of cattle ; hares are very fond of it: they cropped it close to the roots, and neglected the Fustuca ovina, and Fustuca rubra, which were contiguous to it. Itis present in most good meadows and pastures. Festuca pratensis, meadow fescue. Tiis grass is seldom absent from rich meadows and pastures; it is observed to be highly grate- ful to oxen, sheep, and horses, particularly the former. It appears to grow most luxuriantly when combined with the hard fescue, and Poa trivialis. Avena eliator, tall oat-grass. This is a very productive grass, fre- quent in meadows and pastures, but is disliked by cattle, particularly by horses; this, perfectly, agrees with the small portion of nutritive matter which it affords. It seems to thrive best on a strong tena- cious clay. Avena fiavescens, yellow oat-grass, This grass seems partial to dry soils, and meadows, and appears to be eaten by sheep and oxen, equally with the meadow barley, crested dog’s tail and sweet-scented vernal grasses, which naturally grow in company with it. It nearly doubles the quantity of its produce by the application of calcareous manure. Holcus lanatus, meadow soft grass. This is a very common grass, and grows on all soils, from the richest to the poorest. It affords an abundance of seed, which is light, and easily dispersed by the wind. It appears to be generally disliked by all sorts of cattle. ‘he pro- duce is not so great as a view of it in fields would indicate ; but being left almost entirely untouched by cattle, it appears as the most productive part of the herbage. The hay which is made of it, from the number of downy hairs which cover the surface of the leaves, is soft and spongy, and disliked by cattle in general. Anthoxanthum odoratum, sweet-scented vernal grass. Horses, oxen, and sheep, eat this grass; though in pastures where it is com- bined with the meadow fox-tail, and white clover, cock’s-foot, rough- stalked meadow, it is left untouched, from which it would seem un- palatabie to cattle. Mr. Grant, of Leighton, laid down one half a field of a considerable extent with this grass, combined with white clover. The other half of the field with foxtail and red clover. The sheep would not touch the sweet-scented vernal, but kept con- stantly upori the fox-tail. The writer of this, saw the field when the grasses were in the highest state of perfection ; and hardly any tng 3 es 250 performed in a natural manner. The principle is the same as that of the practice alluded to in the’Third Lecture, of giving chopped straw with barley. In washing sheep, the use of water containing car- bonate of lime should be avoided ; for this substance de- composes the yolk of the wool, which is an animal soap, the natural defence of the wool ; and wool often washed in calcareous water, becomes roug gh and more brittle. The finest wool, such as that of the Spanish and Saxon sheep, is most abundant in yolk. M. Vauquelin has analysed several different species of yolk, and has found the principal part of all of them a soap, with a basis of potassa, (i. e. a compound of oily matter and potassa,) with a little oily matter in excess. He has found in them, likewise, a notable quantity of acetate of potassa, and minute quantities of carbonate of potassa and mu- riate of potassa, and a peculiar odorous animal matter. M. Vauquelin states, that he found some specimens of wool lose as much as 45 per cent. in being deprived of their yolk; and the smallest loss in his experiments was 35 per cent. The yolk is most useful to the wool on the back of the sheep in cold and wet seasons; probably the appli- cation of a little soap of potassa, with excess of grease to the sheep brought from warmer climates in our win- ter, that is increasing their yolk artificially, might be useful in cases where the fineness of the wool is of great importance. A mixture of this kind is more conforma- ble to nature, than that ingeniously adopted by Mr. Blakewell; but at the time his labours commenced, the chemical nature of the yolk was unknown. could be more satisfactory. Equal quantities of the seeds of white clover, were sown With each of the grasses; but from the dwarf na- ture of the sweet-scented vernal grass, the clover mixed with it had attained to greater luxuriance, than that mixed with the meadow foxtail.”’ SS Lee ee Wy 2. cy I have now exhausted all the subjects of discussion, which my experience or information has been able to supply on the connexion of chemistry with agriculture. i venture to hope, that some of the views brought forward, may contribute to the improvement of the most important and useful of the arts. I trust that the inquiry will be pursued by others ; and that in proportion as chemical philosophy advances _ towards perfection, it will afford new aids to agriculture. There are sufficient motives connected both with pleasure and profit, to encourage ingenious men to pur- sue this new path of investigation. Science cannot long be despised by any persons as the mere specula- tion of theorists; but must soon be considered by all ranks of men in its true point of view, as the refine- ment of common sense, guided by experience, gradually substituting sound and rational principles, for vague popular prejudices. The soil offers inexhaustible resources, which, when properly appreciated and employed, must increase our wealth, our population, and our physical strength. We possess advantages in the use of machinery, and the division of labour, belonging to no other nation. And the same energy of character, the same extent of resources which have always distinguished the people of the British Islands, and made them excel in arms, commerce, letters, and philosophy, apply with the hap- piest effect to the improvement of the cultivation of the earth. Nothing is impossible to labour, aided by in- genuity. The true objects of the agriculturist are like- wise, those of the patriot. Men value most what they have gained with effort ; a just confidence in their own: powers results from success; they love their country better, because they have seen it improved by their own talents and industry; and they indentify with their in- terests, the existence of those institutions which have afforded them security, independence. and the multiplied enjoyments of civilized life, APPENDIX. ACCOUNT OF THE RESULTS OF EXPERIMENTS ON THE PRODUCE AND NUTRITIVE QUALI- TIES OF DIFFERENT GRASSES, AND OTHER PLANTS, USED AS THE FOOD OF ANIMALS. INSCITUTED BY JOHN, DUKE OF BEDFORD. INTRODUCTION BY THE EDITOR. Or the 245 proper grasses which are capable of being cultivated in this climate two only have been employed to any extent for making artificial pastures, rye grass and cock’s-foot grass; and their application for this pur- pose seems to have been rather the result of accident, than of any proofs of their superiority over other grasses. A knowledge of the comparative merits and value of all the different species and varieties of grasses cannot fail to be of the highest importance in practical agricul- ture. ‘The hope of obtaining this knowledge was the motive that induced the Duke of Bedford to institute this series of experiments. Spots of ground, each containing four square feet, in the garden at Woburn Abbey, were enclosed by boards in such a manner that there was no lateral communica- tion between the earth included by the boards, and that of the garden. ‘lhe soil was removed in these enclo- sures, and new soils supplied ; or mixture of soils were made in them, to furnish as far as possible to the differ- ent grasses those soils which seem most favourable to their growth; a few varieties being adopted for the pur- pose of ascertaining the effect of “different soils in the same plant. The grasses were either planted or sown, and their produce cut and collected and dried, at the proper sea- sons, in summer and autumn, by Mr.. Sinclair, his Grace’s gardener. For the purpose of determining as far as possible the nutritive powers of the different spe- cles, equal weights of the dry grasses or vegetable sub- stances were acted upon by hot water till all their solu- ble parts were dissolved; the solution was then eyapa- 256 rated to dryness by a gentle heat in a proper stove, and the matter obtained carefully weighed. ‘This part of the process was likewise conducted with much address and intelligence by Mr. Sinclair, by whom all the fol- lowing details and calculations are furnished. The dry extracts supposed to contain the nutritive matter of the grasses, were sent to me for chemical ex- amination. ‘The composition of some of them is stated in the table, page 106; I shall offer a few chemical ob- servations on others at the end of this Appendix. It will be found from the general conclusions that the mode of determining the nutritive power of the grasses, by the quantity of matter they contain soluble in water, is suffi- ciently accurate for all the purposes of agricultural in- vestigation. | BOOKS QUOTED IN THE FOLLOWING PAGES. Curt. Lond.—Flora Londinensis. By William Curtis, 2 vols. London 1798, fol. Fl. Dan.—Flora Danica, or Icones Plantarum sponte nascentium in Regnis Daniz et Norvegiz, edite a Ge. Ader. Hafniz 1761, fol. Engl. Bot.—English Botany, by J. E. Smith, M. D.; the Figures by J. Sower- by, London 1790, 8vo, W. B.—Botanical arrangements By Dr. Withering. London 1801, 4 vol. Huds.—Hudsoni Flora Anglica, 1778, vol. ii. Host. G. A—Nic. Vhomz Host Icones et Descriptiones Graminum Austria- corum, vol. i.—ill. Vindobone, 1801, fol. Hort. Kew.—Hortus Kewensis. By W. J. Aiton, vol. i. London 1810. ty rer pas, Ae * Ay Details of experiments on Grasses, By Gronex Stnctarn, Gardener to his Grace _ the Duxz of Beprorp, and Corresponding Member of the Horticultural Society of Edinburgh. I. Anthoxanthum odoratum, Engl, Bot. 647.—Curt. Lond. Sweet-scented ver- nal grass. Nat. of Brit. . At the time of flowering, the produce from the space of an acre equal to ,000091827364 of a brown sandy loam with manure, is OZ. or Ibs per acre Grass 11 oz. 8 dr.* The produce peracre - 125235 0 = 7827 2 80 dr. of grass weigh when dry 213 dr. The produce of the space, ditto 49.153 g 33656 0 = 2103 8 0 The weight lost by the produce of one acre in a poyine is iy a - y - : 5723 10 0 dr. of gras. afford of nutritive matter 1 dr. The produce of the space, ditto - 2375 é 1956 12 > 122 412 At the time the seed is ripe the produce is Grass, 98010 0 — 6125 10 9 oz. The produce peracre - - : 0 80 dr. of grass weight when dry 24 dr s _The produce of the space ditto - 4St¢ 29403 0 = 1837 11 0 The weight lost by the produce of oneacrein drying = 4287 15 0 64 dr. of grass afford of nutritive matter 3.1 dr. , The produce of the space, ditto - 7.13 dr. 4977 10 = SIL) det The weight of nutritive matter which is lost by taking the crop at the time the grass is in flower, exceeding halfits value - = - 188 12 4 The proportional value which the grass at the time of flowering bears to that at the time the seed is ripe, is as 4 to 13. The latter-math produce is Grass, 10 oz. The produce per acre - - 1u8900 0 = 6806 4 0 64 dr. of grass afford nutritive matter, 2.1 dr. 3828 8 = 239 4 8 The proportional value which the grass of the latter-math bears to that, at the time the seed is ripe, is nearly as 9 to 13. The smallness of the produce of this grass renders it improper for the pir- pose of hay ; but its early growth, and the superior quantity of nutritive mat- ter which the latter-math affords, compared with the quantity afforded by the grass at the time of flowering, causes it to rank high as a pasture grass, on such soils as are well fitted for its growth; such are peat-bogs, and lands that are deep and moist. Il. Holcus odoratus. Host. G. A. Growing in woods. Sweet-scented soft grass. Nat of Germany. Flo Ger.—H borealis. Growing in moist meadows. At the time of flowering, the produce from a rich and sandy loam is or lbs, per acre. ‘ OZ. Grass, 14 oz. The produce peracre - - - 152460 0 — 952812 0 80 dr. of grass weigh whendry ~~ 20.2 dr, a The produce of the space, ditto - 57.15 g 39067 did! 2441 The weight lost by the produce ofoneacreindrying - - 7087 0 2 * The weight is avoirdupois; dbs. pounds, oz. ounces, dr. drachms. The weights not named are, quarters of drachms, and fractions of drachms; thus 7.34 means. 7 drachms 1 quarter of a drachm and # of a quarter. —, { HS anu 4s lon) veAt Hg ® * ta] it yy wl ’ o ¥ 12 | ® i . i; APPENDIX. © 259.) C phi ford of ae Nees or ths, per acre As _ G4 dr. of grass afford of nutritive matter 4.1 dr. i “ The produce of the space, ditto 14.33 L024 LoNeqrieh' 15 VS At the-time the seed is ripe the produce is Grass, 40 0z. The produce peracre - - 435600 0—927225 0 @ _ (64 dr of grass, weigh when dry - 28 dr. ; : ub ‘ The produce of the space, ditto ~ 224 dr. 152460 0 = 9528 12 @ The weight lost by the produce of one acre in drying 17696 4 @ 64 dr. of grass afford nutritive matter 5.1 dr. The produce of the space, ditto - 52.2 dr. The weight of nutritive matter which is lost by taking the crop at the time the grass is in flower, being more than half of its value - - - - - 1600 8 16 The proportional value which the grass at the time of flowering bears to that at the time the seed is ripe is as 17 to 21. The produce of laiter-math is Grass, 25 oz. The i produce per acre - - - - - - 272250 0 = 17015 10 Q 64 dr. of grass afford of nutritive matter 4.1 dr. 18079 1 — 112915 1 The grass of the latter-math crop, and of the crop at the time of flowering, taking the whole quantity, anc their relative proportions of nutritive matter, are in value nearly as 6 to iV; the value of the grass at the time the seed is ripe, exceeds that of the latter-math, in proportion as 21 to 17. Though this is one of the earliest of the flowering grasses, it is tender, and the produce in the spring is inconsiderable. If however, the quantity of nu- tritive matter which it affords, be compared with that of any of those species which flower nearly at the same time, it will be found greatly superior, It sends forth but a small number of flower stalks, which are of a slender structure compared to the size of the leaves. This will account in a great measure for the equal quantities of nutritive matter afforded by the grass at the time of flowering, and the latter-math. 35732 13 = 2233 413 @ Il. Cynosurus cerulous. Engl Bot. 1613. Host. G. A. 2. t. 98. Blue more-grass. Nat.of Britain. Sesleria cerulea. At the time the seed is ripe the produce from a light sandy soil is OZ. r. lbs. per acres Grass, 10 oz. The produce per acre - - 108900 0 — 6306 4 0 64 dr. of grass afford of nutritive matter 3.3 dr. 638013 — 398 12 13 é The produce of this grass is greater than its appearance would denote ; the leaves seldom attain to more than four or five inches in length, and the flower stalks seldom arise to more. Its growth is not rapid after being cropped, nor does it seem to withstand the effects of frost, which if it happen to be © severe and_early in the spring, checks it so much as to prevent it from flower- ing for that season; otherwise the quantity of nutritive matter which the grass affords (for the straws are very inconsiderable,) would rank it as a va- luable grass for permanent pasture. LV. Alopecurus pratensis. Curt. Lond. Alo. myosuroides, Meadow fox-tail- grsas. Nat. of Britain. Eng. Bot. 848. At the time of flowering, the produce from the clayey loam is oz. or /bs: per acre Grass, 30 oz. The produce peracre- - - 326700 0'= 20418 12 0 80 dr. of grass weigh when dry - 24 dr. The produce of the space, ditto - 336 ae 98010 (OQ) 1256 Chine The weig't lost by the produce of one acre in drying 14293 2 0 64 dr, of grass afford of nutritive matter 1 2 dr, | The produce of the space ditto - 11.1 pu 7657 Oe 478.99 The produce from a sandy loam is Grass, ie oz 8dr. The produce per aore - 136125 0 = 8597 13 0 80 dr. of grass weigh when dry 24 dr. 2 _ OS The produce of the space, ditto 60 en 40857 9 2552 5 8 60 dr. of grass afford of nutritive matter 1 dr. 29 * The produce of the space, ditto 3.03 212615 o- 1a es red" id APPENDIN. ee At the time ihe seed is ripe, the produce from the clayey loamis ' ba haa i oz. or lbs. per acre be 19 oz. The produce peracre - - 206910 0 = 1293114 0 dr. of grass weigh when dry 36 dr. a Dai aur The produce of the space, ditto 136.34 é 93109 8 = S819 3 2 The weight lost by the produce of one acre in drying 7lll 8 14 64 dr. of grass afford of nutritive matter 2.1 dr. ey * ‘he produce of the space, ditto 9.975 é 84> hae The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being one twenty-fifth part of its value - ~~ - 2 a eT The proportional value-which the grass, at the time of flowering, bears to - that at the time the seed is ripe, is as 6 to 9. The latter-math produce, from the clay loam is : Grass, 12 oz. ‘he produce per acre - = 130680 0 = 8167 8 0 64 dr. of grass afford of nutaitive matter 2 dr. 5 The produce of the space, ditto 6 dr. 4083 12 =. a9 312 The proportional value which the whole of the jatter-math crop bears to that at the time the seed is ripe, is as 5 to 9, and to that at the time of flowering, proportionably as 13 to 24. The above statement clearly shews that there is nearly three-fourths of pro- duce greater from a clayey loam than from a sandy soil, and the grass from the latter is comparatively of less value, in proportion as 4to 6. The straws produced by the sandy soil are deficient in number, and in every respect less than those from the clayey loam : which will account for the unequal quantities of nutritive matter afforded by them; but the proportional value in which the grass of the latter-math exceeds that of the crop at the time of flowering, is as 4 to 3: a difference which appears extraordinary, when the quantity of flower-stalks which are in the grass at the time of flowering is considered. In the Anthoxanthum odoratum the proportional difference between the grass of these crops is still greater, nearly as 4 to 9; in the poa pratensis they are equal; but in all the latter flowering grasses experimented upon, the flower- ing straws of which resemble those of the Alopecurus pratensis or Anthoxranthum odoratum, the greater proportional value is always on the contrary found in the grass of the flowering crop. Whatever the cause may be, it is evident. that the loss sustained by taking the crops of these grasses at the time of flowering is considerable. V. Alopecurus alpinus. Engl. Bot. 1126. Alpine fox-tail grass. Nat. of Scotland. At the time of flowering, the produce from a sandy loam with a small por- tion of manure, is oz. or /6s. per acre Grass, 8 oz. The produce per acre - - 87120 0 = 5445 5 0 60 dr. of grass weigh when dry 16 dr. 39: ne The produce of the space, ditto Binh § cig ee 1478) 048 The weight lost by the produce of one acre indrying 3993.) 5” OM 64 dr. of grass afford of nutritive matter 1 dr. Q The produce of the space, ditto 2 as W614) =) ae VI. Poa alpina. Engl. Bot. 1003. Flo. Dan. 107, Alpine meadow grass, Nat. of Scotland. At the time of flowering, the produce from a light sandy loam, is 4 oz. or lés. per acre Grass, 8 oz. The produce per acre 87120 0 = 5445 0 6 64 dr. of grass afford of nutritive matter 1.2 dr. 204114 = 127 9 14 VIL Avena pubescens. F.ngl. Bot. 1640. Host. G. A. Bit oO; . r Downy oat grass. Nat. of Britain. De WAIT AN bo he RAT PR it ERA ey tie ae Oa, 94 i) |) MARE Ota y 7 f ie eM) vt " iN 4 oh | OS. SS aly, / ' em, [ : APPENDIX. ; ‘ “At the time of flowering, the produce from a rich sandy soil is — j oz. lbs. per acre ae 23 oz. The produce per acre HA - 250470 0 =15654 6 0. 0 dr. of grass weigh when dry - 0 dr. f A The produce of the space, ditto - 158 ae 93926 0 = 5870 6 4. The weight lost by the produce of one acre in EM Sas ek cus in 12 t dr. of grass afford of nutritive matter 1.2 4” 2 ! The produce of the space, ditto - 8.2 izsS 5870 0 = 366 14 6 At the time the seed is ripe, the produce is Grass, 100z. The produce peracre - - 108900. 0 = 6806 4 0 _ 80 dr. of grass weigh when dry ji ly ere é The produce of the space, ditto S82 ar.§ 2000, 0 = 286th ae The weight lost by the produce of one acre in drying mii pes) h).a1s em ae nr en ce 64 dr. of grass afford of nutritive matter 2 dr. 9 The produce of the space, ditto 5 sol $403 2 = 21211 0 The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being more than half of its value - 154 6 38 The proportional value which the grass, at the time of flowering, bears to that at the time the seed is ripe, is as 6 to 8. The produce of latter-math is Grass, 10 oz. The produce per acre - + 108900 0 = 6806 4 0 64 dr. of grass afford of nutritive matter 2 dr. 3403 2=—= 21211 0 The proportional value which the grass, at the time of flowering, bears to that of the latter-math, is as 6 to 8. The grass of the seed-crop, and that of the latter-math, are of equal value. The downy hairs which cover the surface of the leaves of this grass, when growing on poor light soils, almost entirely disappear when it is cultiva- ted on a richer soil. It possesses several good qualities which recommend it to particular notice ; it is hardy, early, and more productive than many others which affect similar soils and situations. Its growth, after being cropped, is tolerably rapid, although it does not attain to # great length if left growing; like the Poa pratensis, it sends forth flower stalks but once in a season, and it appears well calculated for permanent pasture on rich light soils. VUI. Poa pratensis. Curt. Lond. Engl. Bot. 1073. Smooth stalked meadow grass. — Nat. of Britain. At the time of flowering, the produce from a mixture of bog-earth and clay, is oz. or /és. per acre ores , oz. The produce per acre = 1 fe 163350 0 = 10209 6 oO 0 dr. of grass weigh whendry_ - 22:2 dr. ie The produce of the space, ditto - 67.2 dr. 4042 3) == Bal) Oe The weight lost by the produce of one acre in drying PPA Ae yt Amy Rirhes fii tn onic ihe mls i cr 64 dr. of grass afford of nutritive matter 1.3 dr, 4466 9 9 The produce of the space, ditto - 62 is " ea ae At the time the seed is ripe the produce is are, ag Oz. Siar! ita per acre Mg 136825. 0 = 8507 13 0 r. of grass weigh when dry : 32 dr. ate The produce of the space, ditto - 980 . Sa) Core ae aia The weight lost by the produce of one acre in drying : 5104 11 0 64 dr. of grass afford of nutri'ive matter 1.2 47 ; The produce of the space, ditto - 4,2 7% ‘ St 8 ae) 1 Ae i The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being nearly one fourth of its yalue - 79.129 -— oy BD ' RIAN Mf Vie e) - " Pea aah? 262 _ APPBNDIX. _ ia: The produce of latter-math is oz. or lbs per acre Grass, 6 oz. The produce per acre 65340 0 — 4083 12 0 64 dr. of grass afford of nutritive matter 1,3 dr, 1786 10 lll 10.0 The proportional value in which the grass of the latter-math exceeds that of the flowering crop, is as6 to 7, The grass of the seed crop and that of the latter-math are of equai value This grass is therefore of ieast value at the time the seed is ripe; a loss of more than one-fourth of the value of the whole crop is sustained if it is not cut till that period: the straws are then dry, and the root leaves in a sick] decaying state ; those of the laiter-math, on the contrary, are luxuriant and healthy. This species sends forth flower-staikks but once in a season, and these aie the most valuable part of the plant for the purpose of hay; it will, from this circumstance, aid the superior value of the grass of the latter- math, compared to that of the seed crop, appear well adapted for permanent pasture. IX. Poa cerulea.—Var. Poa pratensis. Engl. Bot. 1004. Poa subczxrulea. Short blueish meadow grass. Nat. of Britain. H. Kew. 1—155. Poa humilis. At the time of flowering, the produce from a soil of the like nature as the preceding, is oz. or /és. per acre Grass, 11 oz. The produce per acre Soethis 11970 O =— 7486 14 0 64 dr. of grass afford of nutritive matter 2 dr. ; 9 The produce of the space, ditto 5.2 dn $743 7 = 233 18 80 dr. of grass weigh when dry 24 ar. Reng ‘ The produce of the space, ditto $2.3 is ¢ 35037 0 = 2246 1°10 The weight lost by the produce of one acre in drying - =e oon ls we Pe OY 6 Si ee If the produce of this variety be compared with that of the preceding one, it will be found less; nor does it seem to possess any superior excellence. The superior nutritive power does not make up for the deficiency of produce by 80 lds. of nutritive matter per acre. X. Festuca hordiformis. Poa hordiformis. H, Cant. Barley-like fescue grass. Nat. of Hungary. At the time of flowering, the produce from a sandy soil, with manure is oz or /ds, per acre Grass, 20 0z The produce peracre - - 217800 0 13612 8 O 80 dr. of grass weigh when dry - 224 dr. 2 J The produce of the space, ditto - 96dr.§ 65340 0 — 408 ae The weight lost by the produce of one acre in i drying iin eal on eh a - .- 9528 12° 0 64 dr. of grass afford of nutritive matter 2.1 dr. A The produce of the space, ditto ala tei! ii 7657 0 mm Ge ee This is rather an early grass, though later than any of the preceding spe- ( cies; its foliage is very fine, resembling the #. duriuscula, to which it seems nearly allied, differing only in the lengtlr of the awns, and the glaucous colour of the whole plant The considerable produce it affords, and the nutritive powers it appears to possess, joined to its ‘early growth, are qualities which strongly recommend it to further trial. XI. Poa trivialis. Curt. Lond. Engl, Bot. 1072. Host. G. A, 2. t, 62. Roughish meadow grass, Nat. of Britain. , 4 ; ae ead) fe) oe Ld y ~n”6 (dV oe it Ai ‘ J ‘ ‘] pair's “TON tan : ‘or, ArH , a Dat Vangie Beit) APPENDIX. | . 263 BY!) + At the time of flowering, the produce from a light brown loam, with ma- ott. i» nure, is *° ‘yi oz. or lbs. per acre (a Se oz. The produce Pini acre - - 119790 0 — 7486 14 0 i) dr, of grass weigh when dry - 24 dr. _ |The produce of the space, ditto - 54 33 $5987" 0 2246 _ | The weight lost by the produce of one acre in 2 avying - - : - - - - - . - 5240 13 0 4 dr, of grass afford of nutritive matter 2 dr. The produce of the space, ditto . 5.2 ns STAG 7 me's 285 MAN At the time the seed is ripe the produce is Grass, 11.8 oz, The produce per acre - 125235 0 = 7827 3S 0 80 dr, of grass weigh when dry - 936 dr The produce of the space, ditto - 99.32, 5635512 + 3520°"3) 44 The weight lost by the produce of one acre in i drying slike, fe. me etn la eee ee) fal tte he cc 4 dr. of grass afford of nutritive matter 2.54" 3 rn ‘ The produce of the space, ditto - 7.3% 5381 3 <=) 38649 The weight of nutritive matter which is lost by taking the crop at the time of flowering, exceeding one fourth of its value - 102°, 5 12 The proportional value in which the grass of the seed crop exceeds that at the time of flowering is as 8 to 11. The produce of latter math is Grass, 7 oz. The produce per acre - + 76230 0 = 4764 6 64 dr. of grass afford of nutritive matter 3 dr. 3573 4 = 223 § a 4, The proportional value by which the grass of the latter-math exceeds that of the flowering crop is as 8 to 12, and that of the seed crop as 11 to 12. Here then is a satisfactory proof of the superior value of the crop at the time the seed is ripe, and of the consequent loss sustained by taking it when in flower; the produce of each crop being nearly equal. The deficiency of hay in the flowering crop, in proportion to that of the seed crop, is very stri- king. Its superior produce, the highly nutritive powers which the grass seems to possess, and the season in which it arrives at perfection, are merits which distinguish it as one of the most valuable of those grasses, which affect moist rich soils, and sheltered situatious; but on dry exposed situations it is altoge- ther inconsiderable ; it yearly diminishes, and ultimately dies off, not unfre- quently in the space of four or five years. XI, Festuca glauca. Curtis. f Glaucous fescue grass. Nat. of Britain oz. or lbs. per acre uh 14 oz, The produce per ae 2 Fae 152460 0 = 9528 12 0 0 dr, of grass weigh when dry dr: 2 The nies of t \~ space, ditto 89.2 this's 5 60984 0 = 3811 8 0 The weight lost by the produce of one acre in dryin = 4 t bs ~ = . - - 5717 0 64 dr. of grass afford of nutritive matter 1.2dr.2 9573 4 — 293 5 & The produce of the space, ditto 5.1 dr.§ At the time of flowering the produce is Grass, - oz. The Ae Aes per acre - ic . 152460 0 — 952812 0 80 dr. of grass weigh when dr - Q dr. ¢ The Misaice of the space, ditto - 89.2 60984 O— 4811 8° 0 The weight lost by the produce8 one acre in rying Be o) | lee RRRIR Re mo mys oie 5717 4 0 64 dr of grass afford of nutritive matter 3dr? 7446 9 _. 44610 9 The produce of the space, ditto - 10.2 dr. The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being half of the value of the crop - 223 5 as | Me) en ‘rhe proportional value by which the grass, at the time of flowering exceeds that at the time the seed is ripe, is as 6fo 12. er The proportional difference in the value of the flowering and sced crops of this grass is directly the reverse of that of the preceding species, and affords another strong proof of the value of the straws in grass which is intended for hay. The straws, at the time of flowering, are of a very succulent nature ; but from that period till the seed be perfected, they gradually become dry and wiry. Nor does the root leaves sensibly increase in number or in size, but a total suspension of increase appears in every part of the plant, the roots and seed vessels excepted. The straws of the Poa trivialis are, on the contrary, at the time of flowering, weak and tender; but as they advance towards the period of ripening the seed, they become firm and succulent ; after that peri- od, however, they rapidly dry up and appear little better than a mere dead substance. XII. Festuca glabra. Wither. B. 2. P. 154. Smooth fescue grass. Nat. of Scotland. At the time of flowering, the produce from a clayey loam with manure is oz, or /és. per acre Grass, 21 oz. The produce per acre - 228690 0 —14293 0 0 80 dr. of grass weigh when dry 32 dr. The produce of the space, ditto 134.1 33,$ SESS 0) == oF The weight lost by the produce of one acre in drying = ele ols gisele Pe eh 9 es ha 64 dr. of grass afford of nutritive matter 2 dr. 3 The produce of the space, ditto 10.2 an 7140) 0 <= 420 TOG At the time the seed is ripe the produce is ; Grass, 14 oz The produce per acre SR 152460 O — 9521 12 80 dr. of grass weigh whendry - 32 scat 60984 0 = 3811 8 0 =) The produce of the space, ditto 89.2 The weight lost by the produce of one acre in eth was ‘ : Oe aa Biase eo ST ae dr. of grass afford of nutritive matter Ne ” ° The Shaiiibe of the space, ditto - 4.ly¢ 2977 LS Teo The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, exceeding half of its value - - 260 9 O The proportional value which the grass at the time the seed is ripe, hears to that of the crop at the time of flowering, is as 5 to 8. oz. or /és. per acre The produce of latter-math is ‘Grass, 9 oz. The produce per acre - «+ 98010 0 = 6125 10 6 64 dr. of grass afford of nutritive matter 2 gr ‘” The produce of the space, ditto : Logan § 765 11 = ay ae The proportional value which the grass of the latter-math bears to that of the crop at the time of flowering, is as 2 to 8, and to that of the crop, at the time the seed is ripe, is as 2 to 5. . The general appearance of this grass is very similar to that of the Festuca duriuscula : it is however, specifically different, and infcrior in many respects, which will be manifest on comparing their several produce with each other; but if it be compared with some others, now under genera! cultivation, the re- sult is much in its favour, the soil which it affects being duly attended to. The Anthoxunthum odoratum being taken as an example, it appears that u yy los. per acre Festuca glabra, affords of nutritive matter From the crop at the time of flowering - Sh fi 446.2 639 4d ths =P thie pA { RE RS = At the time the seed is rine, ditto : iN heh 186. § A ME eS fl | ad 7 "AS gays Loi} t EST 4p f dy _ Anthoxanthum odoratum, bd ee } lbs. per acre _ At the timeof flowering, ditto-- - - - - reat 433. ___At the time the seed is ripe, ditto - =. OLN , The weight of nutritive matter, which is afforded by the produce ~ * of one acre of the Festuca glabra exceeding that of the Anthox- nt anthum odoratum, in proportion nearlyas6to9, - - + 199, XIV. estuca rubra. Wither. B. 2. P. 153. Purple fescue grass.Nat. of Britain. At the time of flowering, the produce from alight sandy soil, is 02. or /bs. per acre Grass, 15 oz. The produce peracre’ += - 163350 0 —10209 6 G 80 dr. of grass weigh when dry - 34dr. oe The produce of the space, ditto - 102dr. 36928 12 aaa The weight lost by the produce of one acre in drying - - - 6651 11 0 64 dr. of grass afford of nutritive matter. 1.2 dr. f The produce of the space, ditto - 228. § 3828) 8 = ae At the time the seed is ripe the produce is _ Grass, 16 oz, The produce peracre -~— - 174240 0 —10890 0 0 80 dr. of grass weigh when dry Ba ite P! ee ae The produce of the space, ditto 1153,an§ 78408 0 = 4900 ‘The weight lost by the produce of one acre in drying : - 5 = - - - - - « 5989 64 dr. of grass afford of nutritive matter 2 sige AAS 0 340 The produce of the space, ditto MOET ALE Sent The weight of nutritive matter which is lost by taking the crop when the grass is in flower, being nearly one-third part of its value - - - = - - whe RRNA ft 101 0 8 The proportional value which the grass, at the time of flowering, bears to that at the time the seed is ripe, is as 6 to 8. This species is smaller in every respect than the preceding. The leaves » are seldom more than from three to four inches in length ; it affects a soil si- milar to that favourable to the growth of the Festuca ovina, for which it would be a profitable substitute, as will clearly appear on a comparison of their pro- duce with each other The produce of latter-math is Grass, 5 oz. The produce peracre. - - 54450 0 = 3403 2 0 “64 dr. of grass afford of nutritive matter 1.2 dr. 1276 2—= 7912 6 _ The proportional value which the grass of the latter-math bears to that at the time the seed is ripe is as 6 to 8, and is of equal value with the grass at the time of flowering. XV. Festuca ovina. Engl.fBot. 585. Wither. B. 2. P. 152. Sheep’s fescue grass. Nat. of Britain. At the time the seed is ripe the produce is Oz. or /bs. per acre > id ae produce per acre -* + 87120 0 =-5445 0 0 dr. of grass afford of nutritive matter 1.2 dr. The produce of the space, ditto “Web aich ok 2031 1d oy Fae The produce of latter-math is Grass, 5 oz. The produce per acre . - 54450 0 = 3408 2 0 64 dr. of grass afford of nutritive matter 1.1 dr. 1063 7 =. 67 7 of the produce renders it entirely unfit for hay. If the nutritive powers of this Sa be compared with those of the preceding, the inferiority will appear Us : LJ APPENDIX. (265 The dry weight of this species was not ascertained, because the smallness 4 266 APPENDIX. Festuca ovina, (as above) affords of nutritive matter 1.2 23 Ditto ditto. - ditto 11¢ pe es Festuca rubra ditto ditto 2 w» 32 Ditto ditto ditto 1.2 ¢ y The comparative degree of nourishment which the grass of the Festuea ru- aa ee exceeds therefore that afforded by the F, ovina, in proportion as. to 14. _ From the trial that is here detailed, it does not seem to possess the nutti- tive powers generally ascribed to it ; it has the advantage of a fine foliage, and may, therefore, very probably be better adapted to the masticating organs of sheep, than the larger grasses, whose nutritive powers are shewn to be great- er: hence on situations where it naturally grows, and as pasture for sheep, it may be inferior to few others. It possesses natural characters very distinct from F. rubra. XVI. Briza media. Engl. Bot. 340, Host. G. A. 2. t. 29. Common quacking-grass, Nat. of Britain. At the time of flowering, the produce from a rich brown loam, is oz. _ or lbs. peracre Grass, 14 oz. The produce peracre -_ - 152460 0 — 952812 0 80 dr. of grass weigh when dry - 26 dr. 2 The produce of the space, ditto 72.2,3,dr.§ 49549) 8 Sea At the time the seed is ripe the produce is Grass, 75 oz. The produce per acre - - - 816750 0 —51046 14 0 80 dr. of grass weigh when dry 19 dr. ace The produce of the space, ditto 283 dr. g 193978 2 1203 ae The weight lost by the produce of one acre in drying - - 38923 4 0 64 dr. of grass afford of nutritive matter 5 dr. . ; The produce of the space, ditto - 56.1 dr. ¢ 56285 2 == 2992 ia The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being nearly one third part of its value S/T ve 42a, i— a oikes 1435 11 2 The proportional value which the grass of the time the seed is ripe, bears to that, at the time of flowering, is as 12 to 18, This grass, as has already been remarked, produces a fine early foliage in the spring. The produce is very great, and its nutritive powers are considerable, It appears, from the above particulars, to be best adapted for hay. A very sin- gular disease attacks, and sometimes nearly destroys the seed of this grass: the cause of this disease seems to be unknown; it is denominated Clavus, by some ; it appears by the seed swelling to three times its usual size in length and thickness, and the want of the carcle. Dr. Willdenow describes two dis-— tinct species of it: Ist, the simple clavus, whichis mealy and of a dark colour, without any smell or taste ; 2d, the malignant clavus, which is violet blue, or blackish, and internally too has a bluish colour, a fetid smell, and a sharp pun- gent taste. Bread made from grain affected with this last species, is of a bluish colour; when eaten, produces cramps and giddiness. XXXIX. Bromus littoreus. Host. G. A. P. 7, t. 8. Sea-side brome grass. Nat. of Germany, grows on the banks of the Da- nube and other rivers. At the time of flowering, the produce from a clayey loam is or /bs. per acre ONE hoz, Grass, 61 oz. The produce peracre - - ~ 664290 0 =41518 2 4 * 276 APPENDIX.» 80 dr. of grass weigh whendry = 41.dr. The produce of the space, ditto - 5008-5 § 340448 10 = 21278 0 10. The weight lost by the produce ofoneacreindrying .« 2 90540 1 64 dr. of grass afford of nutritive matter 1.2 dr, 4 {a The produce of the space, ditto 22.34 ¢ 15567 4 = 973 1 At the time the seed is ripe, the produce is’ ' hg 56 oz. The produce per acre - - 69840 0 =38115 0 0 dr of grass weigh when dry 32 dr. a ace wi The produce of the space, ditto 358% g 243086 01 The weight lost by the produce of one acre in drying - 22869 0 64 dr. of grass afford of nutritive matter 3.2-dr. | 29 The produce, of the space, ditto 196 dr. ¢ $3350: 0 == 2008 0a The weight of nutritive matter which is lost by taking the crop at the time of flowering, exceeding one half of its value - - - = - LLL) SG The proportional value which the grass at the time of flowering bears to that at the time the seed is ripe, is as 6 to 14. Tiis species greatly resembles the preceding in habit and manner of growth ; but is inferiof to it in value, which is evident from the deficiency of its produce, and of the nutritive matter afforded by it. The whole plant is likewise coarser and of greater bulk in proportion to its weight. The seed is affected with the same disease which destroys that of the former spe- cies. : XL. Festuca eliator. Engl. Bot. 1593. Host. G. A. 2, t.:79. Tall fescue grass, Nat, of Brivain. At the time of flowering, the produce from a’black rich loam, is Oz, or /bs. per acre Grass, 75 oz. Ths produce per acre io ; 816750 0 —51046 14 0 Reo nrcigh weeny | - 282 ances. 9 area Bete crring if leat py ‘ge Reais m ane 33180 7 8. eer ot maciite mation 52 tos gia At the time the seed is ripe the produce is Grass, 75 oz. The produce per acre — - - 816750 0 =51046 4 0 80 dr. of grass weigh whendry — - 2 dr.2 . wis f The produce of the space, ditto 4.20 dr i 285862 8 =17866 6 0 The weight lost by the produce of one acre in drying PO Aa MON SET aN Wd i aD NL gE NN Di - 33180 7 8 64 dr. of grass afford of nutritive matter 3 dr. 3 gs , The produce of the space, ditto — - 56.1 gages Se 2302 tae The weight of nutritive matter which is lost by jeaving the crop , till the seed be ripe, exceeding one-third part of its value 1595. 3 7 The proportional value which the grass at the time the seed is ripe, bears to that at the time of flowering, is as 12 to 20, The produce of latter-math is Grass, 23 oz. The produce per acre - - 950470 0 =15654 6 0 64 dr. of grass afford nutritive matter 4dr. - 15654 6 = 978 6 6 The proportional value which the grass of the latter-math bears to that of (the crop, is as 16 to 20; and to that at the time the seed is ripe, as 12 to 16, in- verse, 'Vhis species of fescue is closely allied to the Festuca pratensis, from which it diilers in little, except that it is larger in every respect. The produce is nearly three times that of the F. pratensis, and the nutritive powers of the grass are superior in direct proportion, as 6 to 8. oz. or lbs: per acre coo & nan APPENDIX. | 277 — XLE. WMardus stricta. Eng. Bot. 290. Host. G. A. 2, t. 4. “ae Upright mat-grass. Nat. of Britain. — At the time the seed is ripe the produce is . oz. or /bs. per acre Grass, 9 oz. The produce per acre -~ - 98010 0 = 6125 10 O 80 dr. of grass weigh when dry — - 32 dire ag: 5 The produce of the space, ditto - 57 23 : 59204 0 = 2490) The weight lost by the produce of one acre in drying 3675 6 0 64 dr. of grass afford of nutritive matter 9.1 _¢r. The produce of the space, ditto - 5.0% S445 10 ==) 215 9719 XLII. Triticum, Sp. Wheat-grass, At the time of flowering, the produce from a rich sandy loam is oz. or /bs. per acre Grass, 18 oz. The produce per acre oe 196020 0 =12251 4 O 80 dr. of grass weigh when dry - 32 ar. he produce of the space, ditto - 115¢ ¢ 78408 0 = 4900 8 0 The weight lost by the produce of one acre in drying - 7350 12 0 64 dr. of grass afford of nutritive matter 2.2 dr. The produce of the space, ditto - 11.1 mt 7657.0 me 478 9m XL. Festuca fuitans. Curt. Lond. Engl. Bot. 1520. Poa fluitans, Floating fescue grass. Nat. of Britain. At the time of flowering, the produce from a strong tenacious clay, is «OZ. or /bs. per acre Grass, 20 oz, The produce per acre - - 217800 0 —13612 -8 0 80 dr. of grass weigh when dry - - 24 dr.? Q, ; The produce of the space, ditto - - 96 ae 65340 0 — 4083 12 0 The weight lost by the produce of one acre in drying - - 9528 12 0 64 dr. of grass afford of nutritive matter 1.3 ave i The produce of the space, ditto - 8.3 dr. 5955 0s. 302 The above produce was taken from grass that had occupied the ground for four years, during which time it had increased every year; it therefore ap- pears contrary to what some have supposed to be capable of being cultivated in perennial pastures. XLIV. Holcus lunatus. Curt. Lond. FI. Dan, 1181, Meadow soft grass. Yorkshire grass. Nat. of Britain. At the time of flowering, the produce from a strong clayey loam is oz. or /bs, per acre Grass, 28 oz. The produce per acre - - 504920 0 —19057 8 0 80 dr. of grass weigh when dry - 26 a: c The produce of the space, ditto - 157.23 106585 14 = 6601 /9ite The weight lost by the produce of one acre in drying - - 12395 14 2 64 dr, of grass afford of nutritive matter 4 dr. The produce of the space, ditto - 28 ie 19057 | Bone 1 19t e At the time the seed is ripe, the produce is Grass, 28 oz. The produce peracre - - 304920 0 =19057 8 0 80 dr. of grass weigh when dry - 16 dr. The produce of the space, ditto - 89.2% g 60984 0 = 3811 8 0 The weight lost by the produce of one are in drying - - 15246 0 0 64 dr. of grass afford of nutritive matter 2.3 on} 13102 0 = 818 148 The produce of the space, ditto - 19.1 dr. sn \P VSihie aro} : * 4 ey 2) hy as ' r The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, exceeding one-third part of its value - $72. The proportional value which the grass at the time the seed is ripe, to that at the time of flowering, is as 11 to 12. f eee XLY. Festuca dumetorum. Flo. Dan. 700. Pubescent fescue grass. Nat. of Britain. At the time of flowering, the produce from a black sandy loam, is Mae | oz. or dbs. per acre os ; bb +h, ni 16 oz. The produce peracre - - 174240 0 =10890 0 0 © eke 0 dr. of grass weigh when dry , - - 40 dr. ‘ ee __ ._The produce of the space, ditto - 120 a 87120 0 = i iy ee ey The weight lost by the produce of one acre in : tat pi drying - -/ ~ - - - - - - - 5445 0 0 «64 dr. of grass afford of nutritive matter 1 dr. ‘ The produce of the space, ditto - - 4 ant 2722 8 XLVI. Poa fertilis Host. G. A. Fertilis meadow grass. Nat. of Germany. At the time of flowering the produce from a clayey loam, is r oz. or lbs. per acre Grass, 22 or. The produce peracre -~ - 239580 0 —14973 12 0 Me 80 dr. of grass weigh when dry - - 42 47-2 jong g — 7861 3 8 The produce of the space, ditto - 184? The weight lost by the produce of one acre in ; ing wm i a 64 dr. of grass afford of nutritive matter 4.2 dr. = 1052 13 Sem The produce of the space'ditto —- 24.3 dr. iets, - c If the nutritive powers and produce of this species, be compared with any other of the same family, or such as resemble it in habit and the soil which it ~ affects, a superiority will be found, which ranks this as one of the most valuable grasses ; next to the Poa angustifolia, it produces the greatest abundance of early foliage, of the best quality, which fully compensates for the eomparative lateness of flowering. XLVII. Jrundo colorata. Hort. Kew. 1. P. 174. Engl. Bot. 402. Phalaris Nteet: arundinacea. : shea eae Striped-leaved reed grass. Nat. of Britain. At the time of flowering, the produce from a black sandy loam is a oz. or lbs. peracre me Grass, 40 0z. The produce per acre - - 435600 0 =27225 0 oO. 80 dr. of grass weigh when dry 36 dr. wey The produce of the space, ditto - 28.8 dr. 196020 0 —12aahe Or 64 dr. of grass afford of nutritive matter. 4 dr ae aa ag The produce of the space, ditto - 40 nes a(225 0 ae ; bie a The strong nutritive powers which this grass possesses recommend it to the notice of occupiers of strong clayey lands, which cannot be drained. Its produce is great, and the foliage will not be denominated coarse, if compared with those which afford a produce equal in quantity. eS XLVI. Trifolium pratense. W. Bot. 3, P. 137. Broad-leaved cultivai ed clover. Nat of Britain. At the time the seed is ripe flower, the produce from a rich clayey loam is en oz. or /bs. per acre — per acre Grass, 72 oz, The produce peracre - - 784080 0 =49005 — 0 6B AG pres APPENDIX. ie 279° ’ oz. or /bs. per acre 80 dr. of grass weigh when dry = - 20dr. f __ The produce of the space, ditto - 288 in 19602059 sapeeol ¥ __ The weight lost by the produce of one acre in a drying - A - : - 3 - a lied - 3675 4 0 ‘64 dr. of grass afford of nutritive matter 2.2 dr. “ ee __. The produce of the space, ditto - 45 es 30628 2 = 1914 4 2 If the weight which is lost by the produce of this species of clover, in drying, be compared with that of many of the natural grasses, its inferior va- lue for the purpose of hay, compared to its value for green food, or pasture, will appear ; for it is certain that the difficulty of making good hay increases in proportion with the quantity of superfluous moisture which the grass may contain. Its value for green food, or pasture, may further be seen by com- paring its nutritive powers, with those manifested by other plants generally esteemed best for this purpose. Trifolium pratense (as above) affords of nutritive matter - 22d. XLIX. Trifolium ripens (white clover) from an equal quantity of — prass -- - = - - hci ob : - - 2.0 dr. L. Ditto, variety, with brown leaves, ditto - - 4 - 2.2 dr. The grass of the 7’. pratense, therefore, exceeds in value that of the 7. repens, by a proportion as 8 to 10; but it is of equal proportional value with the brown variety. , LI. Burnit (Poterium sanguisorba) affords of nutritive matter - 9.2 dp. LI. Bunias orientalis (a newly introduced plant,) ditto - » =. 2.2 dr. _The proportional value of these two last, and of the T. pratense, and the brown-leaved variety of J. repens, are equal ; they exceed the 7’, repens as $ to 10. The comparative produce of these four last-mentioned species, per acre, has not been ascertained. LIU. Trifolium macrorhizum. Long-rooted clover. Nat. of Hungary. At the time the seed, is ripe, the produce from a rich clayey loam is oz. or /és. per acre - Grass, 144 oz. The produce peracre - - 1568160 0 —98010 9 9 80 dr. of grass weigh when dry - 34 a id The produce of the space, ditto - 9794 666468 0 —41654 4 0 The weight lost by the produce of one acre in Ah! “a - ; ©) layed bie ms a -, += + 56355 12 0 dr. of grass afford of nutritive matter 2.5 dr. ‘ Bh; The produce of the space, ditto - +99 an 67381 14) = 4aT ae The root of this species of clover is biennial : it penetrates to a great depth in the ground, and is in consequence little affected by the extremes of wet or dry weather. It requires good shelter, and a deep soil. The produce, when compared to that of others that are allied to it in habit, and place of growth, proves greatly superior. The following particulars, some of which refer to results stated in the next two pages, will make this manifest : [yifolium pratense ; pace per acre, ae : f : lbs, Be : Broad leaved clover _Affords do. of nutritive matter - - 1914 Medicago sativa. Produces per acre, Grass - ~ = - 70785 * Gucern. From a soil of the < Ditto, Hay, - = - 28314 Iikenature - - Afferds ef nutritive matter - - = 1659 ’ 280 G6) APPENDS ae Hedysarum onobrychis Saintfoin Suey Ditto, Banish oi!) )s> Produces per acre, Grass - = Affords of nutritive matter - - The weight of nutritive matter afforded by the produce of the 7. macrorhizum, exceeding that of the JZ. pratense, in proportion, nearly as7tol5 - - NN Ito Ne ae - scala - 2297 The proportional value of the grass. of J’. pratense to that of 7’. macrerhizum, is 1U to 11, The weight of nutritive matter afforded by the J’ macrorhizum, ex- ceeding that of the Medicago sativa, n proportion nearly as 13 mm ew fe maniac am tl oe ek The proportional value of the grass is as 11 to 6. The weight of nutritive matter which is aiforded by the produce of the 7°. macrorhizum, exceeding thet of the Hedysarum onebryciis in proportion nearlyas Sto 67 - + = 2 The proportional value of the grass, like that of the 7. pratense, is as 11 to 10. - ‘ ' The produce of each of the above-mentioned species was taken from a similar soil, and in the same situation, the conchusions must theretore be con« sidered positive, with respect to such soils only, It is evident that more than twice the quantity of nutritive matter is aflorded by the produce of one acre of the 7, macrorhizum, than from the produce of an equal space covered by _the 7° pratense. Its short duration in the soil (for it sown early in the au- tumn, on a rich light soil, it is only an annual plant) renders it fit only for green food or hay; this in some measure lessens its value, when compared with the 7°. pratense. It possesses the essential property of affording abun= dance of good seed ; and if the ground be kept clear of weeds, it sows itself, vegetates, and grows rapidly, without covering-in, or any operation whatever. For four years it has propagated itself in this manner, on the space of ground which it now occupies, and from which ths statement of its comparative va- lue is made. The produce of lucern in grass, comes nearer to this species in quantity, but is greatly deficient in nutritive matter, as much as 13 to 33, The long contmuance of lucern in the soil is therefore the only merit which it possesses above the two last-mentioned species ; and when that is the object of the cultivator, it will of necessity have the preference. The value of the grass of saintfoin is equal to thet of the T. pratense; and proportionally less than that of the @rifolium macrorhizum, as 10 to 11. The quantity of grass is very small, and on soils of the nature above described, it is doubtless inferior. _ However, from the superior value of the grass, on dry hilly situations or chalky soils it may in such situations possibly be their supe- rior in every respect. LIV. Medicago Sativa. Wither. B. 3, P. 643. Lucern. Nat. of Britain. At the time the seed is ripe, the produce from arich clayer loam is oz or /és. per acre Grass, 104 oz. 'The produce per acre - - 1132560 0 =7078 0 O 80 dr. of grass weigh when dry - ~ 22 dr. S ' The produce of the space, ditto - 665.2% g 453024" 0 See The weight lost by the produce of one acre in drying e e - ‘e - . - e = La 42471 0 0 Me 64 dr. of grass afford of nutritive matter 1.2 dr. 9 The produce of the space, ditto —- 39 dn 20S) Cle LV. Hedysarum onodrychis. Wither. 3. P. 628. , Saintfoin. Nat. of Britain. At the time the seed is ripe; the produce from a rich clayey loam is az. or lbs, per acre Grass, 13 0z, The produce peracre + + 141570 0 — 8848 2 0 eo oe ee er ot a ——— — APPENDIX. ‘ 281 oz. or (bs. per acre 80 dr. of grass weigh when dry . 32 dr. Mites _ ‘Yhe produce of the space, ditto - 834 g Shc Y seaaosD Aine The weight lost by the produce of one acre in ; cat ee SOR een ‘t drying 7 - = asl: \= : 64 dr. of grass afford of nutritive matter 2.2 dr. 55301 = 34510 1 "The produce of the space, ditto - 8.04 LVI. Hordewm pratense.. Engl. Bot. 409. Host. G. A. 1. t. 33. Meadow barley-grass. Nat. of Britain. At the time of flowering, the produce from a brown loam, with manure, is Oz. lbs. per acre Grass, 12 oz. The produce per acre - - 1380680 0 = 8167 8 0 80 dr. of grass, weigh when dry - 32 dr. ! m The produce of the space, ditto Si Or wk i 52272) 0 =) 3300 ag The weight lost by the produce of one acre in , drying - ih ts : - - - - 4900 8 0 64 dr. of grass afford of nutritive matter 3.3dr. 2 The produce of the space, ditto - Ihld.S 7657") 0 = 478 ie LVI. Poa compressa. Engl. Bot. 365. Flat-stalked Meadow-grass. Nat. of Britain. At the time of flowering, the produce from a gravelly soil, with manure, is oz. or /és, per acre Grass, 5 oz. The produce per acre - 54450 0 = 3403 2 0 80 dr. of grass weigh when dry - 34 dr. : The produce of the space, ditto - 34 sks 23141 4 = 1446 9 4 The weight lost by the produce of one acre in Bane : eAtieley hy elaine mA iO * - - 1956 12 12 dr. of grass afford of nutritive matter - 5 dr, oly ‘ i The ie iioe of the space, ditto - 6.1 ¢ 4253 14 = (269 a i The specific characters of this species are much the same as those of the Poa fertilis, differing in the compressed figure of the straws and creeping root only. If the produce was of magnitude, it would be one of the most valuable grasses ; for it produces foliage early in the spring, and possesses strong nutritive powers. LVIM. Poa aquatica. Curt. Lond. Engl. Bot. 1315, Reed Meadow-grass. Nat. of Britain. At the time of flowering, the produce from a strong tenacious clay, is Oz, or (bs, per acre Grass, 186 Oz. The ppoance per acre L - 20225540 —126596 4 0 ifs 94) C mw ha eae “a lr. | a eee weak i Be eeea rate speck dito. r7eg23,$. 1218324. 7AGeaU Iain Yhe weight lost by the produce of one acre in i 1 drying inch uk ee a Oe - ti auidartnl s,s (ihe - 50638 8 0 64 dr. of grass afford of nutritive matter 2.2 ae 79192 -. 4945 2 10 The produce of the space, ditto - 116.1 dr, LIX. Aira aquatica. Curt. Lond. Engl. Bot. 1537. Water hair grass. Nat. of Britain. At the time of flowering, the produce from water, is oz. or lds. per acré Grass, 16 oz. ‘The produce per acre Si daa 1742400 -— 10890 0 0 N tt 282 APPENDIX. oz. or lbs. per-acre 80 dr. of grass weigh when dry - aay di. The produce of the space, ditto - 76.3 Fi 52272. 0 — 3268050 The weight lost By: the Lis of one acre in crying -! = 7623 °00Re 64 dr grass Afford of nutritive matter 2. 1 dr, B , The produce of the space, ditto = - 9 dr. ¢ “e125 10 =:/36 LX. Bromus cristatus. Triticum cristatum, H. G. A. 2, t. 24. Secale prostratum, Jacquin. Nat. of Germany. At the time of flowering, the produce from a clayey loam, is oz. or /és. per acre Grass, 13 oz. The produce peracre -_ - 141570 0'= 8848 O 0 80 dr. of grass weigh when dr - - 36dr. e The prance of the space, ditto - 83.1 dr. 56628 0 == 39305 ane The weight lost by the prodge of one acre in drying - - . - - 5308 14 0 64 dr. of grass Agord of nutritive matter 2, 2 oe The produce of the space, ditto = - 8,02, i 5530, 1 —) se LXI. Elymus Sidiricus. Hort. K. 1, P. 176, Cult. 1758, by William P, aio Siberian lyme grass. Nat. of Siberia. At the time of flowering, the produce from a sandy loam, with manure, is oz. or /bs. per acre Grass, 240z. The produce peracre © - - 261360 0 =16335 0 0 80 dr. of grass weigh when dry - = 28 dr ; The produce of the space, ditto - 134. 17 91476. 0 = olan The weight lost by the peor of one acre in drying - mith oe yal c= Sah ETO Ga ane 64 dr. of grass acd of nutritive matter 2.1 dr. ee The produce of the space ditto - 13.2 dr. cds oA aie DEXII. Jira cespitosa. Host. G. A. 2. t.42. Engl. Bot. 1557. Turty hair grass. Nat. of Britain. At the time the seed is ripe, the produce from a strong tenacious clay is oz. or dbs. per acre Grass, 15 oz. The produce peracre -_ - 163350 6 —10209 6 0 80 dr. of grass weigh when dry - - 26 dr. ¢ Bis The produce of the space, ditto - 135} 53088 12 — 330s The weight lost by the prosuce of one dere in drying - Boel aa bi 6891 5 4 64 dr. of grass afford of nutritive ater we 104.11 2 The produce of the space, ditto - 7.2 dr. i S19 ae LX. Hordeum murinum. Curt. Lond. Engl. Bot. 1971. Wall barley grass. Way Bennet. Nat. of Britain. At the time of flowering, the produce from a clayey loam, is oz. or /bs. per acre Grass, 18 oz. The produce peracre - - 196020 0 —12251 4 0 80 dr. of grass weigh when dry - 28 dr. : tee hy The produce of the space, ditto 100.54 at 4287 dae The weight lost. by the piadare of one acre in drying 2 - - - = jaliee =. (963 RoE 64 dr of grass “eee of nutritive matter 3 were 1 The produce of the space, ditto - 3.33, a679\ 15) EY 2 aPR POE Ren pee eee . APPENDIX. 283 EXIV. Avena fluvescens Curt. Lond. Engl. Bot. 952. Yellow oat grass. Nat. of Britain. At the time of flowering, the produce from a clayey loam, is Oz. or /ésgper acre Grass, 12 0z. The produce peracre = - 130680 “0 — 8167 & 0 80 dr. of grass weigh when dry - 28 dr. es 1G So ORan Ee The produce of the space, ditto - 67.1 dr. 49758 0) = 26 The weight lest by the produce of one acre in drying iby Sm i meh este hy aU ot eh iNet oe la 64 dr of grass afford of nutritive matter 3.3 at The produce of the space, ditto i1.1 dr. 7657. 0 = AG) Ne At the time the seed is ripe the produce is Grass, 18 oz. The produce peracre - - 196020 0 =12251 4 0 80 dr. of grass weigh when dry - 32 an ie 0 The produce of the space, ditto - 115.03 78408 0 20 The weight lost by the produce of one acre in drying - - aie - - - - - 735002 64 dr. of grass afford of nutritive matter 2.1 dr. = 480° ties The produce of the space, ditto - 10.03 pe? en 3 The weight of nutritive matter which is lost if the crop be left till ? the seed be ripe, exceeding one-tenth part of its value - 471311 The proportional value which the grass, at the time the seed is ripe, bears to that at the time of flowering is as 9 to 15. The produce of latter-math is Grass, 6 oz. The produce per acre - - 65340 0 = 4803 12 0 64 dr, of grass afford of nutritive matter 1.1 dr. 1276 2=—= 791272 The proportional value which the grass of the latter-math bears to that at the time of flowering, is as 5 to 15; and to that at the time the seed is ripe, as 5 to 9. This species is pretty generally cultivated in many parts of this kingdom ; and it appears from the above details to be a valuable grass, though inferior to many others. LXV. Bromus sterilis. Engl. Bot. 1030. Host. G. A. 1. t. 16. Barren brome grass, Nat. of Britain. At the time of flowering, the produce from a sandy soil, is Oz. or /bs. per acre Grass, 44 0z. The produce per acre 479160 0 —29947 38 O 80 dr. of grass weigh when dry - 45 dr. The produce of the space, ditto 396 ant 269527 8 —16845 7 8 The weight lost by the produce of one acre in drying - - - - aie = - : - - 13102 0 8 64 dr. of grass afford of nutritive matter Sdr.2 4 The produce of the space, ditto Se Hh ae 37434 6 ios 64 dr. of the flowers afford of nutritive matter 2.2 dr. The nutritive powers of the straws and leaves are, therefore, more than twice as great as those of the flowers. This species, being strictiy annual, is of comparatively little va- jue. The above particulars shew that it has very considerable nutritive pow- ers, more than its name would imply, if taken at the time of flowering ; but if left till the seed be ripe, it is, like all other annuals, comparatively of no value. LXVI. Holcus mollis. Curt. Lond. Wither. B. 2, P. 154. Creeping soft grass. Nat. of Britain. » 284 i APPENDIX. At the time of flowering, the produce from a sandy soil, is oz. or /bs. per acre Grass, 50 oz. The produce peracre .- - 544500 0 —34031 4 0 80 dr of grass weigh when dry - $2 dr. 7 Bi The proguce of the space, ditto 320 dr. ¢ 217800 0.13612 8 0 The weight lost by the produce of one acre in te i - - - - - - - - 20418 12 0 dr. of grass afford of nutritive matter 4.2 dr. ie K The produce of the space, ditto 56.1 nk 58285 2 = 2392 13 2 At the time the seed is ripe the produce is Grass, 31. oz. Vhe produce per acre - - 337590 0 =21099 6 Q 80 dr. of grass weigh when dry - 32 dr. 2KNQ rt The produce of the space, ditto /’ 198.13 g 133036 0 =, 6403 Te The weight lost by the produce of one acre in drying - & f a y - - : - 12659 10 0 64 dr. of grass afford of nutritive matter 3.2 dr. 1 ay 2 The produce of the space, ditto 27.02 ¢ 1846115) 7 ee The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, being nearly one-half of its value - 1238 15'3 64 dr, of the roots afford of nutritive matter 5.2 dr. ‘ The proportional value which the grass, at the time the seed is ripe, bears to that at the time of flowering, is as 14 to 18. The above details prove this grass to have merits, which, if compared with those of other species, rank it with some of the best grasses. The small loss ’ of weight which it sustains in drying might be expected from’ the nature of — ' the substance of the grass; and the loss of weight at each period is equal. ’ The grass affords the greatest quantity of nutritive matter when in flower, which makes it rank as one of those best adapted for hay. LXVIL Poa fertilis. Var. B. Host. G. A. The species, Fertile meadow grass. Variety 1. Nat. of Germany. At the time of flowering, the produce from a brown sandy loam, is Oz. or dbs. per acre Grass, 23 oz. The produce per acre - - 250470 0 =15654 6 0 80 dr. of grass weigh when dry - 54 dr. f The produce of the space, ditto 1562 106448 0) 660s ae The weight lost by the produce of one acre in drying it hi s L a mh hase ~ 9000 14 0 64 dr. of grass afford of nutritive matter 3 dr. 9 yaa nak The produce of the space, ditto - 17.1 ies 11740 12 At the time the seed is ripe, the produce is . Grass, 22 oz. The produce per acre - - 239580 0 —14973 120 80 dr. of grass weigh when dry - 44. dr, 2 ay The produce of the snace, ditto 193.2 ia 151769 0 = 8235 9 0 The weight lost by the produce of one acre in 0) ie es we RI ee a 64 dr. of grass afford of nutritive matter = 5dr. a3 4 B The produce of the space, ditto 22 as 18717 3 = 1169 13 3 The weight of nutritive matter which is lost by taking the crop at the time of flowering, exceeding one-third part of its value is 436 1 3 The proportional value which the grass, at the time of flowering, bears to that at the time the seed is ripe, is as 12 to 20. | The produce of, latter-math is Grass, 7 oz. The produce per acre - +. 1 °-762380' 0, = 4764056 0 64 dr. of grass afford of nutritive matter 1.2 dr. 1786 10 = 111 10 10 : ts 4 APPENDIX. N 285 _ The proportional value which the grass of the latter-math bears to that at the time of flowering, is as 6 to 12, and to that at the time the seed is ripe, as 6 to 20. LXVI. Cynosurus eruceformis. Beckmannia eruceformis. Host. G, A. 3, t. 6. bi - Linear spiked dog’s-tail grass. Nat. of Germany. At the time the seed is ripe the produce is oz. or dbs. per acre Grass, 15 oz. The produce per acre - - 196020 0 =12251 4 © 80 dr. of grass weigh when dry . 36 dr. 2 egqnc pean The produce of the space, ditto 129.2% § 88209. 0 f $513 10 The weight lost by the produce of one acre in drying 4 : z i 7 a ae - = |) 6738 5a 64 dr. of grass afford of nutritive matter‘ 3.1.4 2 Ole 9 The produce of the space, ditto 14.25 § 9954 2— 622 2 2 LXIX. Phleum nodosum. W. B. 2. P.118. Bulbous stalked cat’s-tail grass. Nat. of Britain. At the time of flowering, the produce from a clayey loam, is oz - or /bs. per acre Grass, 18 oz. The produce per acre - - 196020 0 =—12251 4 6G 80 dr. of -grass weigh when dry - 38a a The produce of the space, ditto 1365 g 95109 8, — 3819 -5.)8 The weight lost by the produce of one acre in drying SRR aay Sts ay sk hel Neem lay lary ion - - 6438114 8 64 dr. of grass afford of nutritive matter 2.2 dr. The produce of the space, ditto nfs Leak nll 7657 0 == (478 7S This grass is inferior in many respects to the Phleum pratense. It is sparing- ty found in meadows. From the number of bulbs which grow out of the straws, a greater portion of nutritive matter might have been expected. This seems to prove, that these bulbs do not form so valuable a part of the plant as the joints,. which are so conspicuous in the Phlewm pratense, the nutritive powers of which exceed those of the P. nodosum, as 8 to 28. LXX. Phleum pratense. Wither. 2. P. 117. Meadow cat’s-tail grass Nat. of Britain, At the time of flowering, the produce from a clayey loam, is ; oz. or /bs. per acre Grass, 60 oz. The produce per acre - - 653400 0 =40837 8 0 80 dr. of grass weigh when dry - 34 ate eee The produce of the space, ditto - 408 dr. 27095). 0 ae The weight lost by the produce of one acre in drying - 4 - - -- 234819 0 64 dr. of grass afford of nutritive matter 2.2 dr. 2 25593 7 = 1595 3 0 he produce of the space, ditto 37.2 dr. § The weight of nutritive matter which is lost by leaving the crop till the seed be ripe, exceeding one-half of its value Sih) POR oy ae At the time the seed is ripe the produce is Grass, 60 oz. The produce peracre_ - . 643400 0 =40837 8 80 dr. of grass weigh when dry =), 38 dr. The produce of the space, ditto 456 ane 310363 1/0 = 19397 13410 The weight lost by the produce of one acre in : ME eta oF) oA. ae ae LAO 286 . APPENDIX. cea nei _ oz. or (bs. per acre dr of grass afford of nutritive matter 5.3 dr ¥ The produce of the space, ditto « 86.1 BLY 58703 14 = 3068 15 14 The produce of latter math is Grass, 14 oz The produce per acre - - 152460 0 — 9528 12 0 64 dr. of grass afford of nutritive matter 2 dr 4764 6 = 297 12 6 64 dr. of the straws afford of nutritive matter 7 dr. The nutritive powers of the straws simply, therefore, exceed those of the leaves, in proportion as 28 to 8; and the grass at the time of flowering, to tiat at the time the seed is ripe, as 10 to 23; and the latter-math to the grass of the flowering crop, as 8 to 10, The compar ative merits of this grass will appear, from the above par ‘uculars, to bé very great; to which may be added the abundance of fine foliage that it produces early in the spring. In this respect it is inferior to the Poa Jfevtilis, and Poa angustifolia only. The value of the straws at the time the seed is ripe, exceeds that of the grass at the time of flowering, as 28 to 10; a cireum- stance which increases its value above many others; for, by this property, its valuable early foliage may be cropped, to an advanced period of the season, without injury to the crop of bay, which, in other grasses which send forth their flowering straws early in the season, would cause a loss of nearly one-half of the value of the crop, as is clearly proved by former examples; and ‘his property of the straws, makes the plant peculiarly valuable for the purpose of hay. \ LXXI. Phileum pratense. Var. minor. Wither. B. 2,118. Var. 1. Meadow cat’s-tail grass. Var. Smaller. Nat. of Britain. At the time of ripening the seed, the produce from a clayey loam, is ‘ oz. or /ds. per acre Grass, 40 oz. The produce peracre - - 435600 0 —27225 0 0 80 dr of grass weigh when dry - 34 ns 185130 0 —11570 10 0 The produce of the space, ditto 272 di The weight lost by the Reedice of one acre in drying - - oe = ee TSGS A Grae 64 dr. of grass < afford af: nutritive matter 2.3 dr. ive The produce of the space, ditto 272 dr. ¢ 1817 = 1169 13 3. The produce of latter-math is, Grass, 14 oz. The produce per acre - - 152460 0 = 95298 12 0 64 dr. of grass afford of nutritive matter 1.2 dr. 3573 4= 223 5 4 LXXII. Elymus arenarius. Engl. Bot. 1672. Upright sea lyme grass. Nat. of Britain At the time the seed is ripe, the produce from a clayey loam, is Oz. or dbs. peracre Grass, 64.0z. The produce per acre - - 696960 0 =43560 0 0 80 dr. of grass weigh when dry = ieeeaolcdes 2: He The produce of the space, ditto - 576dr.§ 392040 0 728002 eae The weight lost by the Beodace of one acre in drying : - - 18957 8 .0. 64 dr. of grass sft of tee matter fo dr. The produce of the space, ditto - 80 dr a 544500 — SiS en \ LXXUI. Elymus menicidatue. Pendulous lyme grass. Engl. Bot. 1586. Pendulous sea lyme grass. Nat. of England. APPENDIX. 287 At the time of flowering, the produce from a sandy soil, is Oz. or lbs, peracre Grass, 30 oz. The produce per acre - - 326700 0 —20418 12 0 80 dr of grass weigh when dry Sal ars The produce of the space, ditto 192 on 159680 | 0. ==) Ahiaaa ne The weight lost by the produce of one acre in RVR im ee a ee 1925 64 dr. of grass afford of nutritive matter 3.1 dr. e404 Q The produce of the space, ditto 24.14 g 16220 ee LXXIV. Bromus inermis. Host. G. A. 1, t. 9. Awnless brome-grass. Nat. of Germany. Introduced by Mr. Hun- neman in 1794. At the time the seed is ripe, the produce from a black sandy soil, is ! oz. or /bs. per acre Grass, 18 oz. The produce per acre - - 196020 0 —12251 4 0 80 dr. of grass weigh when dry 35 dr. The produce of the space, ditto 126 ae 85758 12 — 5359 14 12 The weight lost by the produce of one acre in : drying ieag ee . ated Che att a 6891 5 4 4 dr. of grass afford of nutritive matter 4.1 dr. The produce of the space, ditto 19.03 $ 19016 15.-— 313))5eee The produce of Jatter-math is Grass, 13 oz. The produce per acre me) tm 141570 0 = 8848 2 0 64 dr. of grass afford of nutritive matter 1.1 dr. 2765 0 = 17213 O LXXYV. Agrostis vulgaris. Wither. Bot. 2, 132. Hud. A. capilaris, Dr. Smith, A. arenaria. Fine bent grass. Nat. of, Britain. At the time the seed is ripe, the produce from a sandy soil, is : oz. or /bs per acre Grass, 14 oz. The produce per acre - - 152460 0 = 9528 12 0 80 dr. of grass weigh when dry - 40 dr. era ‘ The produce of the space, ditto 112 ik 76230, 0 — 47o4qGiam The weight lost by the produce of one acre in drying x x eh ae - - : - - - = 4764 6 O 64 dr. of grass afford of nutritive matter eek 4019 15 = 251 3415 The produce of the space, ditto 5.1). This is one of the most common of the bents, likewise the earliest; in these respects, it is superior to all others of the same family, but inferior to several of them in produce, and the quantity of nutritive matter it affords. As the species of this family are generally rejected by the cultivator, on account of the lateness of their flowering ; and this circumstance, as has already been obser- ved, does not always imply a proportional lateness of foliage, their compara- tive merits in this respect may be better seen, by bringing them into one view, as to the value of their early foliage. ‘The apparent difference Their nutritive of time. powers. Agrostis vulgaris Middle of April - 1.23 palustris One week later > 2:0 stolonifera Two, ditto - - 3.2 canina Ditto, ditto - - LS stricta Pitto, ditto - - 1.2 yy 288 | APPENDIX. The Nah difference Their nuteitive of time. powers. mivea Three weeks, ditto 2 Y hittoralis Ditto, ditto 3 m repens Ditto, ditto RSV mexicana Ditto, ditto 2 Jfascicularis Ditto, ditto 2 LXXVI. Agrostis palustris. Wither. Bot. 2, P. 129. Var. 2, alba. Engl. Bot: 1189. A. alba. Marsh bent grass, At the time of flowering, the produce from a bog-earth, is oz. or /bs. per acre Grass, 15 oz. The produce per acre wets 163350 6 =—10209 6 @ 80 dr. of grass weigh when dry 36 dr, ‘ Ain a The produce of the space ditto - 108 dr. 0 The weight lost by the produce of one acre in drying - - - - - - : - - - 5615 2 8 64dr. of grass afford of nutritive matter 2.3 dr. Sa The produce of the space, ditto - 10.13 018 1S = ee At the time the seed is ripe the produce is Grass, 20 oz. ‘The produce per acre - - - 217800 0 =13612 8 0. 80 dr. of grass weigh when dry 32 dr. te The produce of the space, ditto 128 ans 87120 0) ee The weight lost by the produce of one acre in drying - - - - - : 4 = = - 8167 8 0 64 dr. of grass afford of nutritive matter 2.3 dr. 2 ey The produce of the space, ditto 133 dr. § 9358) 9 = eed The weight of nutritive matter which is lost by taking the crop at the time of flowering, being one-fourth part of its value - 146 3 10 The proportional value of grass, in each crop is equal. EXXVIL. Panicum dactylum. Eng. Bot. 850. Host. G. A. 2, t. 18. Creeping Panic grass. Nat. of Britain, At the time of flowering, the produce from a sandy loam, with manure, is f Oz. or lbs. per acre Grass 46 oz. The produce per acre - - 500940 0 =—S1308 12 50 dr, of grass weigh when dry 36 dr. } 90K A9¢ be The produce of the space, ditto 331.0% 2251230 Ce The weight lost by the produce of one acre in _drying - - - - - - - - - - 17219 13.0 64 dr. of grass afford of nutritive matter 2 re 15654 6 =97866 6 0 The produce of the space, ditto - 23 dr. / LXXVUI. Agrostis stolonifera. Engl. Bot. 1532. Wither. Bot. 2, 181. (Fiorin, Dr. Richardson.) Creeping bent. Nat. of Britain. At the time of flowering, the produce from a bog soil, is oz. or /bs. per acre Grass, 26 oz. The produce per acre - - 283140 0 =17696 4 0 80 dr. of grass weigh when dry - 35 dr. Pati The produce of the space, ditto ~ | 182 dr, §), 329873 12 — cree Ae The weight lost by the produce of one acre rn Leer) > APPENDIX. 289 z or dbs. per acre a + Qi. _ 64 dr. of grass afford of nutritive matter 3.2 a 15484 3 = 967 12 3 The produce of the space, ditto 22.3 dr. At the time the seed is ripe the produce is Grass, 28 oz. The produce per acre - - §04920 0 =19057 8 0 80 dr. of grass weigh whendry~ - 36 dr. ¢ 9 a The produce of the space, ditto 201.2 ISB) YS The weight lost by the produce of one acre in drying - A Ne - : = HG ie - - 10481 10 0 64 dr. of grass afford of nutritive matter 3.2 dr.2 i 6675 — 1042 3 ¢ The produce of the space, ditto 24.2 dr.§ Nae Oe Cine The weight of nutritive matter which is lost by taking the crop at the time of flowering, being nearly one-fourteenth of its value, 74.7% 2 LXXIX. Agrostis stolonifera. War. angustifolia. A Creeping bent, with narrow leaves, Nat. of Britain. At the time the seed is ripe, the produce from a bog soil, is ‘ ox. or /bs. per acre Grass, 24 oz. ‘The produce per acre’ - - 261360 0 —16335 0 0 80 dr. of grass weigh when dry 36 dr. ¢ 1 o veel Vir The produce of the space, ditto 172.33 11612) OS ae The weight lost by the produce of one acre in drying a - : « 2 2 - 4 2 8984 4 @O 64 dr. of grass afford of nutritive matter 3 dr. a ~ ~ The produce of the space, ditto 18 ant becocteih, giana: rae The weight of nutritive matter afforded by the produce of one acre of the Agrostis stolonifera, exceeding that of the variety in proportion, is6to8~ - - - - - - - 216) Sik The above details will assist the farmer in deciding on the comparative va- lue of this grass. From a careful examination it will doubtless appear to pos- sess merits well worthy of attention, though perhaps not so great as has been supposed, if the natural place of its growth and habits be impartially taken into the account. From the couchant nature of this grass, it is denominated couch-grass, by practical men, and from the length of time that it retains the ag power, after being taken out of the soil, is called squitch, quick, full of ife, Kc. EXXX. Agrostis canina. Engl. Bot. 1856. Brown bent. Nat. of Britain. At the time of flowering, the produce from a brown sandy loam, is ' Oz. or /bs. per acre Grass, 9 oz. The produce per acre - = 9810 0 = 6125 10 0 80 dr. of grass weigh when dry 34 dr. ud The produce of the space, ditto = OSE a 43013 0) ora ae The weight lost by the produce of one acre in Ry eM ue, a ea a US ar Ral _ 64 dr. of grass afford of nutritive matter 2.2 dr. é The produce of the space, ditto - 5.213 3828) 8 oe ane LXXXI. Agrostis canina. Var. mutice. Awnless brown bent. Nat. of Britain. At the time the seed is ripe, the produce from a sandy soil, is oz. or /bs: per acre _ Grass, 21 oz. The produce per acre - - 228690 0 =—14293 2 0 Q0 290 APPENDIX. Sal Oz. or bs. per acre 80 dr. of grass weigh when dry = - 24 dr. The produce of the space, ditto 100.3% I 4287 15 0 The weight lost by the ipreee of one acre in drying - - - = 10005 3 0 64 dr. of grass afford of riley matter 13 3 dr. 9 The produce of the space, ditto - 9.03 g 6253 3 = Oe The weight of nutritive matter which the produce of one acre of the awnless variety, exceeds that of the last mentioned species 151 8 11 LXXXII. Agrostis stricta. Curt. A. rubra. Upright bent grass. Nat. of Britain. At the time the seed is ripe the produce from a bog soil, is Grass, 11 oz. The produce per acre - = 119790 0 = 7486 14 @ 80 dr. of grass weigh when dry - 29 dr. pe The produce of the space, ditto - 634 dr, Sars - aris ie The weight lost by the prepuce of one acre in drying “ " - - - .- 477215 0 64 dr. of grass a ord of nutritive matter 1.2 ge ; The produce of the space, ditto - 4.0 -5 ss 2807 9 = LXXXI. Agrostis nivea. Snowy bent grass. Nat. of Britain. At the time the seed is ripe, the produce from a sandy soil, is oz. or lbs. per acre Grass, 7 oz. The produce per acre - - 76230 0 = 4764 6 0 80 dy of grass weigh when dry - 22dr. 9 The produce of the space, ditto - 30.34 § 20068 «4a The weight lost by the bipduee of one acre in dryiig - i - - = 3454 3 0 64 dr. of grass afford of ieee erutter 2 dr. an9 pat 2 The produce of the space, ditto - Bi 2382...3 aes ie LXXXIV. Agrostis fascicularis. Wuds. Var. canina. Curt. Tufted leaved bent. Nat. of Britain. At the time of A venng, the produce from a light sandy soil, is oz. or dbs. per acre Grass, 4 oz. The produce per acre - - 43560 0 = 2722 8 0 80 dr. of grass weigh when dry . 20 dr. (a) The produce of the space, ditto - 16 dr. 10890 0 = The weight lost by the produce of one acre in Brce ‘s a ‘ - - - - - 2041 14 0 64 dr. of grass afford of nutritive matter 2 dr. 4 The produce of the space, ditto mee a 361, 4 as LXXXV. Festuca pinnata. Bromus pinnatus. Eng]. Bot. 730. Spiked fescue. Nat. of Britain. At the time the seed is ripe, the aati from a light sandy soil, with ma- ‘nure, is or dbs. per acre Grass x oz. The eae per acre 326700 0 20418 12 @ 80 dr. of grass weigh when dry — - 32 dr. The produce of the space, ditto - 192dr. % 130680 | 0) = ea Se CS 4 ‘ The produce of the space, ditto - 7.2dr,§ APPENDIX. 291 Of. or Js. per acre The weight lost by the produce of one acre in Crying.) 20" - a Re - 6 HA2251, 4,56 64 dr. of grass afford of nutritive matter 1.1 dr. oN The produce of the space, ditto - 9.1 2 é 6380 13 398 12 13 » LXXXVI. Panicum viride. Curt. Lond. Engl. Bot. 875. Green Panic grass. Nat. of Britain. At the time the seed is ripe, the produce from a light sandy soil, is Grass, 8 oz. The produce per acre = - 87120 0 = 5445 0 80 dr. of grass weigh when dry > 32 ic a ae . The produce of the space, ditto - 512 agi bs ¢ 2116 ae The weight lost by the produce of one acre in =) drying, - - : - - : - . - - 3267 0°90 64 dr, of grass afford of nutritive matter 1.2 dr. e" The produce of the space, ditto ey oie 2041 14 = 197 9 14 LXXXVIL. Panicum sanguinale. Curt. Lond. Engl. Bot, 849. Blood coloured panic grass. Nat. of Britain, At the time the seed is ripe, the produce from a sandy soil, is Grass, 10 oz. The produce per acre - - 108900 0.= 6806 4 0 64 dr. of grass afford nutritive matter 1.02. 1914 4=-11910 4 This and the preceding species are strictly annual, and from the results of this trial their nutritive powers appear to be very inconsiderable. The seed of this species, Mr. Schreber describes (in Beschreibung der Graser) as the manna grass. In Poland, Lithuania, &c. it is collected in great abundance, when after being thoroughly separated from the husks, it is fit for use. When boil. ed with milk, or wine, it forms an extremely palatable food, and is most com- “onan made use of whole, in the manner of sago, to which it is in general pre+ erred. LXXXVIII. Agrostis lobata. Curtis, lobata carenaria. Lobed bent grass. At the time of flowering, the produce from a sandy soil, is oz, or Ms. per acte Grass, 10 oz. The produce per acre - - 108900 0 = 6806 4 0 80 dr. of grass weigh when dry ~— - - 40 dr. é : The produce of the space, ditto - - 80d». 54450 0 = 3403 2 0 The weight lost by the produce of one acre in drying - 2) took - - : - 3403 2 0 64 dr. of grass afford of nutritive matter 3 dr. ll 5104 11 = 3519 0 Th LXXXIX. Agrostis repens. Whither. Bot. A. nigra. Creeping rooted bent, black bent. Nat. of Britain. At the time of flowering the produce from a claycy loam, is oz. > /és. per acre Grass, 9 oz. The'produce per acre - - 98010 0 6125 10 Q 80 dr.of grass weigh when dry == ~—~ 35 dr.2 . The produce of the space, ditto - - 63dr.§ 42879 6 == 2679 15 6 The weight lost by the produce of one acre in : Z Te ne “fer aio Pavia Seabee 5 3445 10 10 4 dr. of grass afford of nutritive matter dr. 2 x The produce of the space, ditto - 63dr. $ 4594 287 2°38 ie L9 I 292 eae APPENDIX. XC. Agrostis Mexicana, Hort. Kew. 1. P. 150. | Pata Mexican bent grass. Nat. of S. America, Introduced, 1780, by M. G. Alexander, & 4 At the time of flowering, the produce from a black sandy soil, is | oz. or lbs. per acre Grass, 28 oz. The produce per acre - - 304920 0 —19057 8 0 80 dr. of grass weigh when dry _ - 28 dr. P The produce of the space, ditto - 156.35 ¢ 106722 0 = 670 2 0 The weight lost by the produce of one acre in drying = INN ae i - + ° SO eee eo ena 64 dr. of grass afford of nutritive matter 2 dr. Ze ‘The produce of the space, ditto - - 14dr ¢ 9528 12 595 8 12 XCI. Stipa pennata. Eng. Bot. 1356. ~ Long-awned feather grass. Nat. of Britain. At the time of flowering, the produce from a heath soil is oz. or /bs. per acre Grass, 14 oz. The produce per acre - = 152460 0 = 9528 1200 80 dr. of grass weigh when dry - ‘- 29 d The produce of the space, ditto < 81 } 55266 12 — a ee The weight lost by the produce of one acre in drying : - - - - - 6074 9 4 64 dr. of grass afford of nutritive matter 2.3 dr. The produce of the space, ditto - 9.23 63510) 408 ae XCIL. Triticum repens. Engl. Bot. 909. Creeping rooted wheat grass. Nat. of Britain. At the time of flowering, the produce from a light clayey loam is oz. or dbs. per acre Grass, 18 oz. The produce peracre -~ - 196020 0 =122951 4 0 80 dr. of grass weigh when dry - 32_dr. Oh The produce of the space, ditto mie Ws 78408 0 — 4800 ae The weight lost by the produce of one acre in ; drying -, ee Tiel ele Wiis tt aR b= hie July 18 Aug. 6 Hedysarum onobrychis - July 18 Aug. 8) 10) PROTA OA AEE ARE AT ie a RE NRE ERR APPENDIX. 295 Names. Time of flowering. Time of Orman the —flordeum pratense - - pratense - - July 20 Aug. ~ SAGBEBi oe | Poa compressa - - * July 20 Aug. 8 Poa aquatica - - ° July 20 Aug. 8 | Bromus cristatus - - F July 24 Aug. 10 Elymus sibiricus - - July 24 _ Aug. 10 Aira cespitosa = - - July 24 Aug. 10 Avena flavescens : - July 24 Aug. 15 | Bromus sterilis - - July 24 Aug. 20 | Holcus mollis - : - July 2 Aug. 20 Bromus inermis - - July 24 Aug. 20 Agrostis vulgaris - - July 24 Aug. 20 Agrostis palustris - July 28 Aug. 28 } Panicum dactylon = = - July 28 Aug. 28 Agrostis stolonifera - July 28 Aug. 28 Agrostis stolonifera (var. } July 28 Aug. 28 Agrostis canica - - July 23 Aug. 28 " Agrostis stricta - . July 28 Aug. 30 if Festuca pennata - “ July 28 Aug. 30 Panicum viride - - Aug. 2 Aug. 15 Panicum sanguinale - . Aug. 6 Aug. 20 | Agrostis lobata - - Aug. 6 Aug. 20 Agrostis repens - - Aug. 8 Aug. 25 Agrostis fascicularis - Aug. 10 Aug, 30 Agrostis nivea - - : Aug. 10 Aug. 30 Triticum repens - - Aug. 10 Aug. 30 Alopecurus agrestis © - - Aug 10 Sept. 8 Bromus asper : - Aug. 10 Sept, 10 Agrostis mexicana - Aug. 15 Sept. 25 Stipa pennata - - . Aug. 15 Sept. 25 Melica cerulea - - Aug. 20 Sept. 30 Phalaris cananiensis_ - als Aug. 50 Sept. 30 Dactylus cynosuroides* ~- | Aug. 30 Oct. 20 * In the experiments made on the quantity of nutritive matter in the Cea cut at the time the seed was ripe, the seeds were always separa- and the calculations for nutritive matter, as is evident from the de- {sts made for grass and not hay. —— ee ee ODOE el Of the different Soils referred to in the Appendix. Iy books on agriculture and gardening much uncertainty and confusion arises from the want of regular definitions of the various soils, to distinguish them specifically by the names generally used: thus the term bog-earth, is almost constantly confounded with peat-moss, and heath-soil ; also the term ‘light loam,’ ‘ heavy soil,’ &c. are given, without distinguishing whether that be § light’ from sand, or this ¢ heavy’ from clay. In minute experiments, it is doubtless of consequence to be as explicit as possible in those particulars. The following short descriptions of such soils as are mentioned in the details of the experiment are here given for the above purpose. Ist. By ‘loam’ is meant any of the earths. combined with decayed animal, or vegetable mattter. 2nd. ‘Clayey-loam,’ when the greatest proportion is clay. Srd. ‘ Sandy-loam’ when the greatest proportion is sand. 4th. ‘ Brown-loam’ when the greatest proportion consists of decayed vege- table matter. 5th, ‘ Rich-black loam,’ when sand, clay, animal and vegetable matters are grea i ' ded eas vegetable matter in the greatest. » ‘light brown loam,’ &c. are varieties he terms ‘light sandy soil €, as expressed. \ Perae: i.” ! ee Observations on the chemical Compositions of the nutritive Matter afforded by he in Grasses in their different States. By the Editor. eh HAVE made experiments on most of the soluble products supposed to con- tain the nutritive matter of the grasses, obtained by Mr. Sinclair; andl have analysed a few of them. Minute details on this subject would be little inter- esting to the agriculturist, and would occupy a considerable space; 1 shall _ therefore content myself with mentioning some particular facts, and some ge- neral conclusions, which may tend to elucidate the inquiry respecting the fit- ness of the different grasses for permanent pasture, or for alternation, as green crops with grain. \ __ The only substances which I have detected in the soluble matters procured _ from the grasses, are mucilage, sugar, bitter extract, a substance analogous to albumen, and different saline matters. Some of the products from the after- — math crops gave feeble indications of the tanning principle. rae The order in which these are nutritive has been mentioned in the First _ Lecture ; the albumen, sugar, and mucilage, probably when cattle feed on grass or hay, are for the most part retained in the body of the animal; andthe bitter principle, extract, saline matter, and tannin, when any exist, probably for the most part voided in the excrement, with the woody fibre. The ex- tractive matter obtained by boiling the fresh dung of cows, is extremely similar _ _ inchemical characters to that existing in the soluble products from the grasses. And some extract, obtained by Mr. Sinclair, from the dung of sheep and of — __. deer, which had been feeding upon the Lolium perenne, Dactylis glomerata, and Trifolium repens, had qualities so analogous to those of the extractive matters obtained from the leaves of the grasses, that they might be mistaken for each other. The extract of the dung, after being kept for some weeks, had still the odour of hay. Suspecting that some undigested grass might have re- mained in the dung, which might have furnished mucilage and sugar, as well as bitter extract, 1 examined the soluble matter very carefully for these sub- _ ‘stances. It did not yield an atom of sugar, and scarcely a sensible quantity of A - mucilage. * Ry OF _ Mr. Sinclair, in comparing the quantities of soluble matter afforded by the mixed leaves of the Lolium perenne, Dactylis glomerata, and Trifolium repens, _ and that obtained from the dung of cattle fed upon them, found their relative ~ proportions as 50 to 13 Ey It appears probable from these facts, that the bitter extract, though soluble in a large quantity of water, is very little nutritive ; but probably it serves the = purpose of preventing’, to a certain extent, the fermentation of the other ve- getable matters, or in modifying or assisting the function of digestion, and may — thus be of considerable use in forming a constituent part of the food of cattle. _ A-small quantity of bitter extract and saline matter is probably all that isneed- ed, and beyond this quantity the soluble matters must be more nutritive in __ proportion as they contain more albumen, sugar, and mucilage, and less nutri- — _ tive in proportion as they contain other substances. 7 ae __ In comparing the composition of the soluble products afforded by different crops from the same grass, I found, in all the trials I made, the largest quanti- ty of truly nutritive matter, in the crop cut when the seed was ripe, and least bitter extract and saline matter; most extract and saline matter in the autumn- al crop ; and most saccharine matter, in proportion to the other ingredients, in the crop cut at the time of flowering. I shall give one instance: . 100 parts of the soluble matter obtained from the Dactylis glomerata, cut in — flower, afforded, e Ofsugar = = Of mucilage - APPENDIX. ' Of coloured extract, and saline matters, 2 i with some matter rendered insoluble “, by evaporation oI alae abi 8 100 parts of the soluble matter from the seed crop, afforded, Sugar - aire ie : 9 parts Mucilage —- - - - A 85 Extract, insoluble, and saline matter 6 100 parts of soluble matter from the after-math crop, give, Of sugar - mM my ie 11 parts Of mucilage - - - - 59 Of extract, insoluble, and saline mat- ters. - - - - - 30 The greater proportion of leaves in the spring, and particularly in the late autumnal crop, accounts for the difference in the quantity of extract ; and the inferiority of the comparative quantity of sugar in the summer crop, probably depends upon the agency of light, which tends always in plants to convert sac- charine matter into mucilage or,starch. Amongst the soluble matters afforded by the different grasses, that of the Elymus arenarius was remarkable for the quantity of saccharine matter it con- tained, amounting to more than one-third of its weight. The soluble matters om the different species of Festuca, in general afforded more bitter extractive matter than those from the different species of Poa. The nutritive matter trom. the seed crop of the Poa compressa was almost pure mucilage. The soluble matter of the seed crop of Phleum pratense, or meadow cat’s tail, afforded. more sugar than any of the Poa or Festuca species. The.soluble parts of the seed crop of the Holcus mollis and Holcus Janatus, contained no bitter extract, and consisted entirely of mucilage and sugar. Those of the Holcus odoratus afforded bitter extract, and a peculiar substance having an acrid taste, more soluble in alcohol than in water. All the soluble extracts of those grasses that are most liked by cattle, have either a saline or subacid taste ; that of the Holcus Janatus is similar in taste to gum arabic. Pro- bably the Holcus lanatus, which is so common a grass in meadows, might be made palatable to cattle by being sprinkled over with salt. I have found no differences in the nutritive produce of the crops of the dif- ferent grasses cut at the same season, which would render it possible to esta« blish a scale of their nutritive powers ; but probably the soluble matters of the after-math crop are always from one-sixth to one-third less nutritive than those from the flower or seed crop. In the after-math the extractive and saline mat- ters are certainly usually in excess ; but the after-math hay mixed with sum. mer hay, particularly that in which the fox-tail and soft grasses are abundant, would produce an excellent food. Of the clovers, the soluble matter from the Dutch clover contains mpst muci- lage, and most matter analogous to albumen: all the clovers contain more bitter extract and saline matter than the common proper grasses. When pure cloyer is to be mixed as fodder, it should be avith summer hay, yather than after-nrath: ay. La | } t wire uh Ra IN WG Xo . Acids, account of those found in vegetables . Age of trees, by what limited - = Alcohol, theory of its formation - : z Alburnum, uses of - - - a Alkalies, method of ascertaining their presence in plants effects produced by, in vegetation - Animal substances, their composition, &c a _——___—- decomposition of > haa Atmosphere, nature and constitution of - - - Animal matter, mode of ascertaining its existence in soils Bark, its office and uses’ - - - - - Barks, their relative value for tanning skin - Blight in Corn, its cause - = - - Bread, its manufacture, theory of its production Burning, its use inimproving soils - + = Canker in trees, probable mode of curing - Carbonic acid, a part of the atmosphere -~ - necessary to vegetation - - Cements, on those obtained from limestone __ - Chemistry, its application to agriculture - - importance in agricultural Bone Combustibles, simple, referred to = 2 Combustion, supporters of, mentioned way hl Courses of crops, particular ones recommended Corn, its tillering, theory of this operation . Diseases of Plants, their causes discussed Earths, on those found in plants - - - Electricity, its influence on vegetation -~ - Elements chemical, of bodies - - ~ laws of their combinations Excrements, use of as manures - = ° Fairy rings, theircauses - - - - Fallowing, theory of WDM me a Fermentation, phenomenaof - -~ - Fly-turnip, plan for destroying or percnene Flowers, their parts and office - - ee¢ @y @ Geology, referred to as teaching the nature of rocks Grafting, general views on this process - - ie) te Y Leh Fon LS EG | at Pee es ea ar 5 ‘ 1 ' . t 5 ‘ ' ? ' a t e ' t = io) J es et Sy eit pee | oe oo t>,t-—1....5 9 as so ' pat [e.2} oO Na ie tert | oo PS 300 . INDEX. : Shaan, on those fit for pasture oa RTS oa Fea Gravitation, its effects on plants - « ‘ . & Y Green crops recommended : Ee 9 INDEX TO THE APPENDIX. Alerostis canina, brown bent == “ . - canina var. mutica, awnless brown bent ——— fascicularis, tufted-leaved bent - - lobata, lobed bent grass mehr Woasaes 1h fi hee mexicana, mexican bent grass - - ———._ nivea, snowy bent grass - mL is ——— palustris, March bent grass - - ——— repens, creeping rooted bent - ~ stricta, upright bent grass - - - stolonifera, fiorin creeping bent - = - (eas ——— stolonifera var. angustifolia, creeping bent narrow leayes — vulgaris, fine bent grass mad oS Sean Aira aquatica, water hair grass - e cespitosa, turfy hair grass - = — flexuosa, waved mountain hair grass - Alopecurus agrostis, slender fox-tail grass - — alpinys, alpine fox-tail grass - - — pratensis, meadow fox-tail grass - Anthoxanthum odoratum, sweet scented vernal grass Arundo colorata, striped-leaved reed grass - Avena elatior, talloat grass - = - - ——-— flavescens, yellow oat grass. - - - pratensis, meadow oat grass - - - pubescens, downy oat grass e - “ Briza media, quaking grass - - - - Bromus asper - = ~ - - - cristatus = = = - - - diundrus - = ms - ~ - —— erectus, upright perennial brome grass —— inermis, awnless brome grass - - ——— litioreus, sea-side brome grass ae ier ——— multiflorus, many-flowering brome grass ———— tectorum, nodding pannicled brome grass sterilis, barren brome grass - - Bunias orientalis - - - - - Cynosurus ceruleus, blue moor grass - - ————~ cristatus, crested dog”’s-tail grass - ——— eruceformis, linear spiked dog’s-tail grass Dactylis cynosursides, American cock’s-foot grass glomerata, round-headed cock’s-foot grass Elymus arenarius, upright sea lyme grass “ geniculatus, pendulous sea lyme grass sibericus, Siberian lyme grass 304 } INDEX, 4 ae Festuca calamaria, veed-like fescue grass - + = © (= «@ ——$——._ cambrica - - « - = - - = ~ 2 duriuscula, hard fescue grass - - - - - = dumetorum, pubescent fescue grass 8 SMe, Senna —— elatior, tall fescue grass Bae estat en Cs «a - —— fluitans, floating fescue grass, = tLe omeane US aie glabra, smooth fescue grass - - - ° - - —— glauca, glaucous fescue grass - ° - - 3 LN Sas —— hordiformis, barley-like fescue grass - - - - - -—— loliacea, spiked fescue grass - - - = - + —— myurus, wall fescue grass - - - - = Tae -——— ovina, sheep’s fescue grass - - - ~ 25 - - pennata, spiked fescue grass wi) Easel a Ret hel Ae el ae —— pratensis, meadow fescue grass | - - - - < rubra, purple fescue grass = af Ny. - - - “ Hedysarum onobrychis, sainfoin - : ah Ws Lh “ys - 980 Hordeum bulbosum, bulbous barley grass = - - - - fi 275 — murinum, wallbarley grass - , - - - mip RS 282 pratense, meadow barley grass - -~ = - . mera: { Holcus lanatus, meadow soft grass: - - = “ uy ° i 977. mollis, creeping soft yrass + ~ i a it a s 283. ~——- odoratus, sweet scented soft grass = = - - - a 258 Loliwm perenne, perennial rye grass - - - - - - : 971 Medicago sativa, lucerne - s 2 3 ez 2 = S A 580 , WMelica cerulea, purple malic grass - Sear Ee - - ‘ 293 Milium effusum, common millet grass 2 . = ° < - 970 Vardus stricta, upright mat grass - - 2 - . - a 277 Panicum dactylum, creeping panic grass = = _ 2 - - 288 — sanguinale, blood coloured panic grass = A oe . 2914 — viride, green panic grass - - ~ 2 - - = 291 Phalaris cananiensis, common canary grass mie : - : 295 Phileum nodosum, bulbous-stalked cat’s-tail grass - - - - 285 pratense, meadow cat’s-tail grass —- - - - = “ 985 ——~ var. minor, meadow cat’s-tail grass, var. smaller . 985 Poa alpina, alpine meadow grass = - z * - . = 260 angustifolia, narrow-meadow grass - - - ee - - 268 aquatica, reed meadow grass = 3 “ : = - 281 — cerulea, v. p. pratense, short bluish meadow grass - " - 262 ~ compressa, flat-stalked meadow grass = “ . - 281 ——— cristata, crested meadow grass - - = - = - - 274, ~-—— elatior, tall meadow grass = . + a : : “ . 269 feriilis, fertile meadow grass “ - a - “ oI “ 278 " var. 6. fertile meadow grass, var. 1. . - » - 284. —— maritima, sea meadow grass : : : “ . = 272 ~—— pratensis, smooth-stalked meadow grass - - - - - 261 -— trivialis, roughish meadow grass ee Potirium sanguisorba, burnet —- . ~ 3 Z = a 3 279 Stipa pennata, long armed feather grass - - - - - - 29% Trifolium microrhizum, long-rooted clover - - : ante os Ae —— pratense, broad-leaved cultivated clover —- - - - 278 Pepens, White clover - = - < - - - - 279 Triticum repens, creeping rooted wheat grass - - - > - 292 ~————-— sh. Wheat grass - - . : = : - - . DY dope a TREATISE ON SOULS AND MANUIRIES, AS FOUNDED ON ACTUAL EXPERIENCE, AND AS COMBINED WITH THE LEADING PRINCIPLES OF AGRICULTURE: IN WHICH THE THEORY AND DOCTRINES OF SIR HUMPHRY DAYY, AND OTHER AGRICULTURAL CHEMISTS, ARE RENDERED FAMILIAR TO THE EXPERIENCED FARMER, - BY A PRACTICAL AGRICULTURIST. PHILADELPHIA: PUBLISHED BY B. WARNER, 171, HIGH STREL'). 1824 ‘Wil PREFACE. THEORY would always coincide with practice, if the speculator could hold to the mind’s eye a complete model of the subject discussed ; could see all the parts in action together, as a machine is surveyed; and mear sure excitements and obstructions precisely as they ope- _ rate. But, in treating of arts which depend for their success on natural operations, the most difficult part of the task is, to assign the proper degree of influence to the many causes and qualities which act invisibly, and cannot be controlled by man. Hence, the philosopher who exercises the strongest intellect on previous systems of vigriculture, and on the knowledge accumulating — from the progress of practical experience and scientific discovery, cannot be certain that some latent interme- diate impulse in the machine of vegetation, has not elu- ded his anxious inquiry, or that he is aware of all the causes which exist, and of their conducing to a general effect. Amidst these difficulties, the T'heorist cannot advance any considerable way beyond the track of eaperience, in the pursuit of materials for a new system, without be- ing liable to move on a line which subsequent experience may be compelled to abandon. Meanwhile, an in- dependent and equally specious hypothesis may uphold the reasonableness'of séme branch of established prac- fice impeached by the: new system, and vindicate from iv PREFACE, the name of prejudice that slow and circumspect transi- tion from tried courses to alleged improvements, which prevents a whole country from being involved in the speculations and risks of an experimental farm. The views of Sir Humeury Davy in regard to Soils and Manures may, on many fundamental points, be re- ceived without dispute, as no less sound and practical than they are original and ingenious: but he has advan- ced some new doctrines, and become the advocate of some recent partial practices, which do not accord with the general experience of Gardeners and Agriculturists. Nevertheless, by the connection with the subtile princi- ples and problems of Chemistry under which these are given, the Practical Farmer who may feel dissatisfied with a particular part of the professor’s theory, because it is at variance with his own maxims derived from ex- perience, is perplexed and silenced by the reasoning, being unable to enter with perspicuity inte the grounds of argument drawn from the depths of philosophy: thus he is ashamed to question a train of deductions by which he is conducted to a doctrine in which he does not confide. But when theory is opposed to theory, the practical man is disembarrassed, and raised to the situation of an arbiter. . It may be added, that some few points among the difficulties of Chemistry, treated by Sir Humphry Davy as fundamental principles, are not yet considered as es- tablished by all the great Chemists; consequently, the speculative deductions from these must stand over for approval, until the assumed principle be exploded or confirmed. PREFACE. re ¥, In the following Treatise, the leading doctrines of this illustrious Contributor to the formation of an en- lightened system of Agriculture are brought under re- view; in order that such as are obviously well founded, or tenable against superficial objections, may be recom- mended to general practice ; as well by corroborating facts and observations, as by the connected order and simplified form in which they are presented s—and that such as are open to considerable objection, either on prac- tical grounds, or by collision with a contrary hypothe- sis, may be exhibited at the tribunal of reason, and sub- jected to the test of experience, in so plain a shape as shall bring them within the grasp of the Practical Ag- riculturist who may have formed no previous acquaint- ance with Chemical Science. GONTENTS. Sate seater Use or Tue Sor * a - = & = . - r On THE Basis of Soirs - - - s : - Pa - Tenms ror Soins Derinep - ° - - ” . . On THE ImrrovemeNT or Sorts: I, By the Admixture of Earths, to si Shad the Texture of the Soil Tests of Soils - - - - - - - ° Correctives of ill-constituted Soils : 1. Iron in its Acid Combinations - - - - 2, Excess of pure Calcareous Matter - - - = ~ 3. Excess of Carbonate of Lime - ” - - - 4. Redundant Sand - - ” - - - - a. Excess of Vegetable Matter. - - °- @ 6. Redundancy of Clay Date a Tl. By Draining - - - . - S z I. By Paring and Burning . - IV. By Turning-in Green re as Manure - V. By Fallowing . ~ ps 3 Vi. By Irrigation - - . - - - VIL. By applying Earths as Manures + 1, Lime as a Solvent Nh lime) - - =» - 2. Mild Lime - - - - . - * Time of laying on Lime - PO he ONGNY by 3, Magnesia - af ER 4 yer Oh WE, Wo 4. Phosphate of Lime - rae ek .) - 5. Gypsum - -_ - - . - - 6. Burnt Clay - - - . - - - Considered as the Food OF HABTIES 2) in ies. de VIU. By introducing Mineral or Saline Sesrarerinete as Manures : 1. Common Salt - - - - ° so 2. Comparative Effect of different Salts +) =a ve - 1X. By Manuring with Refuse Substances not excrementitious : 1. Street and Road Dirt, and the PReepings of siyier 2. Soot - - - - - 3. Coal ashes - - A. Coal-water - . 5. Wood-ashes - - 6, Carbonate of Ammonia 7 8 9 . Coal-tar - = . . Bones - - - . Horn - 10. Hair, Feathers, and Woollen Rags 11. Refuse of Skin and Leather - - 12, Bleacher’s Waste ~~ . - . ew Cok Bet Tet wee ' z= 8 ‘ ‘ : : : oS See Es eee | : ' ' Pend t ] ‘ ' s t \) est) 6 8 Re 8 ee 38, Vili CONTENTS, Pace 13, Soaper’s Waste, = - 3 Ue 60 14, Fluids of dissolved Animal Substine’s TMK, 60 Blood .-- = CA met ean ha «le 60 Sugar-baker’s oir wy ee lee CAN ttt N= 0 tee an 60 Graves . = | Ss 61 Oily Sulistanced brain Oil and Blubber - > 9 ie 61 Oil-cake - - - = 4 : - 3 “, 62 15. Refuse Fish - - - - - - - - - 62 16 Carrion - - - - “ Ss ° - 62 17. Rape-seed Cake - 21 (fot im 8) he) 63 18. Malt Dust - - - - ~ - . - . 63 19. Sea-weed - - - - - s 63 20. Dry Straw, bad Spoiled Hay PN a) feat eg 63 21. Vegetable Mould - SM tral Wyn - - - - 64, 22. Woody Fibre: - - - - - - - Be 64 Tanner’s Spent Bark - - - . . . - 64 Inert Peaty Matter - - - ° - - 64 Shavings of Wood and Saw-dust - - - : . 65 | The Fibre and Grain of Wood + -— - = Die 65 23. Ashes of Vegetables not Noon - =) = 0h Sil 65 Burnt Straw ~ . - . - - - 65 Peat-ashes_ - - - oem - . Sier ch S 65 %&. By Excrementitions Substances applied as Manure : a.) Dune of Sea-birds: 2) 0 ls) /e |) oh ina) fh 66. 2. Night-soil ET Sa anes Need RN wl Se 66 3. Pigeon’s Dung wijlknd 4. )-ite pn lath Dt gh) Ae 67 4. The Dung of Domestic Fowls ° oy! Ao she 67 5. Rabbit’s-Dung - ee em Me te 68 6. The Dung of Cattle Se en a 68 7. Hog-dung wei mE me CAN nm a fan 70 S,, Urine) 4-04) - ° L . é ‘. Z 4 70 JManagement of Manure From the Homestead : Professor Davy’s Theory of Composite Kapaa - . . 71 Objection noticed by the Professor —- ©) ii ie 72 His own Practical Application of the above Thea : 72 Free Remarks on the T econye and on ne Poles) ‘Application 72 Copel aoeess - B ~ ss b 83 Additional Notes, &e. - * - 0 * . e 85 ‘TREATISE ON SOILS AND, MANURES. USE OF THE SOIL. 4 ORRECT views of the ‘office of the soil disclose the ration- ale of approved modes of tillage ; if one mode is found supe- rior to another, they lay open the cause of it; and proceeding from courses which are experienced to be beneficial, a principle is thus obtained for extending their application. One great use of the soil, is to afford a bed for the plant, _ and a cover for its roots from the sun and from the wind ; while the roots, by taking hold of the ground, act as stays and supports for the trunk of the plant. A second important office is that both of a depository and a channel of nutriment : In these rela- tions, the soil ought to contain a certain proportion of common vegetable basis, and of peculiar substances found in plants on analysis ; it ought again to be easily permeable to air; also po- rous, for the percolation of water and passage of fluid manures ; well fitted for allowing a plants by the fine tubes within its-roots, to derive sustenance slowly and gradually from the dissolved and soluble substances mixed with the earths. As the systems of roots, branches, and leaves, are very dif- ferent in different vegetables, so specific plants have a a preference for peculiar soils in which they flourish most. ‘The plants that have bulbous roots require a looser and lighter soil than such as ‘have fibrous roots: and those of the latter, which have short and slender fibrous radicles, demand a firme? soil than such as have tap roots or extensive lateral roots. Hence, when succes- sive crops of the same plant have drawn out from a soil the pe- culiar properties most adapted to its individual nature, the bed of earth becomes less fit for the same plant, until it has been rested and recruited: while it may be fitter for some other plant of a different constitution than it originally was; though ex- hausted in regard to the crop which it has long borne, it may be fresh for a new sort of vegetable. In short, the principles laid down in the “ Practical Gardener,” (Introduction to the Kir CHEN GARDEN, under the head Rotation of Crops,) are more or fess applicable to all the branches of Gardening and Agriculture. B Wwe 10 BASIS OF SOILS. its ) Sir Humphrey Davy, an illustrious ornamant of the English school of Chemistry, is not more distinguished by his discoveries in philosophy, than by seeking, with true ambition, to make pro- found knowledge subservient to the common arts by which the common wants of mankind are supplied; he has contributed largely to the service of agriculture, by publishing his scientific researches into the composition of earths, and the true food of plants. With the object of founding a course of agricultural improvement on fixed principles, he has communicated, in the Elements of Agricultural Chemistry,* some very important re- sults from a systematic train of experiments. We propose to lay before the Reader the substance of his leading conclusions, divested, as much as possible, of chemical terms; and to re- view the peculiarities of his system with candour and indepen- dence ; concentrating, for unity of method, scattered articles belonging to the same branch of rural economy. In the extensive field of his inquiry, he touches on the prin- ciples of many other arts; it therefore becomes necessary, in sketching an outline after him, which shall embrace only the _ department of agriculture, to connect the extracts by details and observations for which Sir H. Davy is not responsible. * Soils, in all cases, consist of, either a mixture of finely di- vided earthy matter,}—or of earthy matters not reduced to pow- der, such as gravel and other stones; more or less combined with decomposed animal or vegetable substances ; saline ingre- dients, also, frequently lodge in a soil; and the earthy matters are frequently accompanied with the oxides of minerals, parti- cularly the oxide of iron.t The earthy matters form the true basis of the soil; the other parts, whether naturally present, or artificially introduced, operate in the same manner as manures. Four Earrus generally abound in soils :§ 1. The aluminous, i. e Clay, including alum; 2. The sz/iceous, 2. e. Flint, in va- rious stages of decomposition, including flinty sand; 3. The calcareous, i. e. Limestone, under various modifications, including marle, chalk, and chalky sand; 4. The magneszan, i. e. Magne- sia, a stone sometimes mistaken for common limestone, but when burnt and applied to land it is much longer in passing from a caustic to a mild state, and under most circumstances is highly pernicious to vegetation. The small proportion in * This work, which will be frequently referred to, is entitled, Elements of Agricultural Chemistry, in a Course of Lectures for the Board of Agriculture. By Sir Humphry Davy, LL.D. F.R.S. &c. &c. Sve. American, 1820. fIbid.p.15. + Ibid. pp. 111, 123. § Ibid. p. 15. TERMS FOR SOILS. 44 which it may be sometimes beneficial, will be afterwards ex- plained. ; The above are the only earths which have been hitherto found in plants. Other primitive earths sometimes enter into soils by the pul- verization of rocky materials. TERMS FOR SOILS DEFINED. The popular terms for soils are seldom applied with precision. What one man calls a marle, another will call a clay ; and so on. But if a general circulation and acceptance could be obtained for the principles of definition judiciously laid down by Profes- sor Davy—according to which a soil is to be styled a clay, sand, or chalk; a marle, loam or peat; or a compound of these—the eharacteristic terms would be every where intelligible. In framing a system of definitions, a soil is to take a particular denominationfrom a particular kind of earth, not exactly in pro- portion as that earth may preponderate, or not, over others in form- ing the basis of the soil, but rather in proportion to the influence which a particular kind of earth, forming part of the staple, has on tillage and vegetation, Thus, as clay is a substance of which a comparative small quantity will give a cold and stubborn cha- racter to a soil, the name clayey is often properly bestowed, where the quantity of pure clay to be collected from a given piece of land, is but as 8 to 42, compared with the quantity of sand which another field may contain, and yet barely deserve the denomination of sandy. “The term cLAYEY should not be given to a soil which con~ tains less than one-sixth of aluminous matter ;’’ because less than that will not be attended with the common effects which govern the culture, and limit the crops, for a clayey soil. The epithet sanpy is not an appropriate distinction for any soil that does not contain at least seven-eight parts of sand ; and sandy soils are to be distinguished into s7/zceous sandy or flinty sand, and calcareous sandy or chalky sand. The word catcareous, or any denomination implying the presence of mild lime or chalk, is not properly applied unless a specimen of the soil is found strongly to effervesce with acids, or unless water having a channel in the soil affords a white earthy deposit when boiled. A MARLE consists of mild lime with a small proportion of clay, and sometimes of peat, with a mixture of marine sand and animal remains; the lime having originated, for the most part, from the decomposition of sea-shells. ' A soil may be treated as MAGNrstan, where but a small 142 i IMPROVEMENT OF SOILS. comparative quantity of magnesian stone is present ; as will be explained in treating of Magnesia as a manure. * The combination of animal or vegetable matter in an inferior proportion with earthy matter, but not lower than one-sixth, makes a Loam: the word /oam should be limited to soils con- taining at least one-third of impalpable earthy matter (distin- guishable by the touch from sand, chalk, or clay,) combined with decayed animal or vegetable substances not exceeding half the weight of the mere earth; the earthy matters may compre- hend aluminous, siliceous, or calcareous ingredients, and in some cases be mixed with mineral oxides: according to the pro- portions of which, the soil may be red loam, brown loam, or black loam ; and in regard to the basis, a clayey loam, a sandy, or a chalky loam. A superior proportion of vegetable matter, that is to say, an excess of this above half the bulk of the earthy basis, makes a PEAT. ‘To bring this kind of soil into successful cultivation, the quantity of vegetable matter must, in most cases, either be reduced or counterbalanced by the admixture of some of the simple earths. Where a slight tincture of any particular mineral substance has a strong effect on vegetation, this quality should be indica- ted by a corresponding word prefixed to the principal name for the soil. Thus the presence of either salts of iron, or sulphate of iron, ought to be marked by prefixing the term rERRUGINOUS to the denomination taken from the basis, to remind the culti- vator that the effect on vegetation will be pernicious, unless he has recourse to an effective remedy. If on the contrary, oxzde . of iron be found in the soil, there is seldom any occasion to no- tice it in the name: in small quantities, it forms a useful part of soils, and has been found to constitute from a 15th to a 10th part of several highly fertile fields: it is found in the ashes of plants. To persons unacquainted with chemistry it may be use- “ful to add, that salt of zron exhibits the crystals obtained from iron by the action of an acid fluid. Sulphate of iron is Cop- peras, a native kind of which is produced in some soils by the effect of the springs and earths on each other. Black oxide of tron is the substance that flies off from red-hot iron when Jt 1s hammered. Iron appears to be only hurtful to vegetation in its acid combinations. See Tests of Soils. - IMPROVEMENT OF SOILS. Almost all the expedicnts for improving, enriching, or cor recting a soil, known to agriculturists, may be comprehended under one of the following heads: IMPROVEMENT OF SOILS. 7 43> 1. The admixture of Earths to improve the Texture of the Soil. 2. Draining. 3. Paring and burning. 4, Turning in Green Crops as Manure. 5. Fallowing. 6. Irrigation. 7. Applying Earths as Manures. 8. Introducing Mineral or Saline Elements as Manures, 9. Manuring with Refuse Substances not excrementitious: 10. Manuring with Excrementitious, Substances. I. By the Admixture of Earths, to improve the Texture of the Sozl. This is a distinct thing from applying Earths as a manure. It is of avail in proportion as the smallness of the tract, or the value of the plant, to be cultivated, allows the free introduction of new earths, until the staple of the land is composed as desired. Almost all sterile soils are capable of being thus improved ; and sometimes the latent pernicious quality which destroys the va- lue of an extensive tract of land, can be corrected without much expense. The best constitution of a soil, is that in which the earthy materials are properly balanced, so as to combine as many ad- vantages of different ingredients as are compatable, and so as to obviate the defects attending any single kind of earth. | The ground, or basis of the soil, should be well adapted for the admission of air, and for the percolation of moisture, with-. out retaining it in winter. ‘A well-tempered aptness in the soil to absorb water frot air, and to retain it in a latent form, is clearly connected with fer- tility. The power to absorb water by attraction, and to hold moisture without being wet, depends on the mechanical struc- ture of the particles of earth, and the balancing effect of diffe- rent earth, ‘Thus sand will attract moisture, but will not keep it long under the influence of heat. Clay will long retain wa- ter which has fallen upon it, and always keep moist under a hu- mid atmosphere: but in continued dry weather, with summer heats, the surface of it, being baked into an almost impenetrable erust, is little capable of absorbing moisture. Hence crude clays form equally bad lands in extremely wet or extremely dry seasons, Chalk is of a middle nature, in this respect. [t re- sults, that the soils best adapted for supplying the plant with moisture by atmospheric exhaustion are compositions* of sané * Elements of Agricultural Chemistry, p. 141. ’ 44 IMPROVEMENT OF SOILS. aes ea _ finely divided clay, and pulverized chalk, with a proportion of animal or vegetable matter.* wif) There is besides, in particular earths, an agency subservient to vegetation, which depends on chemical affinities, in those earths, for elementary substances floating in the air, or deposited in the soil. Thus, both pure clay and carbonate of lime have an attraction for volatile oils and solutions of oil and sapona- ceous matters, and for much of the pulpy stuff first disengaged from organic remains. Hence a limited proportion of these earths contributes to form a rich and generous soil; because they long preserve in their pores the prepared nourishment of vege- tables, parting with it gradually as itis drawn by growing plants, and refusing it to the fainter action of air or water. The properties of a soil may be aggravated or tempered by _the nature of the Sussort. When the upper layer rests upon a bed of stone, or of flinty gravel, it is much sooner rendered dry by evaporation; an effect which is beneficial, or otherwise, as the climate is moist in excess, or inclined to aridity. A clayey foundation counteracts the readiness of flinty sand to part with moisture to a drier climate; so does a bed of chalk in a less degree. A soil is neither fit for tillage nor pasture, if it consist en- tirely of impalpable matters,t or of pure clay, pure silica, or . pure chalk. Sand may abound in a higher proportion than the more tenaceous earths, without causing absolute barrenness. Thus a tolerable crop of turnips has been raised on a soil of which eleven parts in twelve were sand. A good turnip soil from Holkham was found to contain $ parts of siliceous sand. If the quantity of impalpable earth and finely divided organic matter be a little increased beyond what a sand plant requires, it will suffice for good returns of barley. Although wheat de- pends more on a rich staple, happily the constituents of land fit for it are combined with very great diversity. An excellent wheat soil, from Middlesex, afforded % of sand; the rest was chalk, silica, and clay, pretty equally distributed, with a propor- tion of organic matter so surprisingly small (only 22 parts in 500) that it may be apprehended some considerable substance, convertible into food for a growing plant, might be included in the chalk. Chalk may in the next degree form the prepondera- ting earth of good soil. A large portion of England is chalk; * The compound of earth, which seems every where most favourable ta vegetation, is that which consists of one-third of chalk, half of sand, and a fifth of clay: from a Paper on the Chemical Analysis of Soils, translated from the Italian of Fabbroni, by Arthur Young, Esq. (Annals of Agriculture, vol. viii. 173.)—* A fifth of clay :” this proportion is too large ; independent of consumable or cropping manure ; by which the clay should be reduced to one- sixth or lower, } Elements of Agricultural Chemistry, p. 133. TESTS OF SOILS. _. 45 and many of the districts where it is the staple earth, liberally repay cultivation.* The Warp-land (alluvial soil) in the East Riding of York- shire, is a strong clayey loam, the fertility of which can hardly be equalled. The sediment gradually adding to the depth of this warp-land, being brought from the higher country by the numerous rivers and streams which open into this common es- tuary, is composed of a variety of substances. Decomposed vegetable and animal matter should be from one-eighth toa fourth of the bulk of the earthy substances, according to the dependence of the expected crop on the nutritive power of the soil. Many soils (observes Sir H. Davy) are in popular language distinguished as cold; and the distinction, though at first view it may appear to be founded on prejudice, is as just on philoso- phical principles as it is consonant to the experience of the farmer. Some soils are constituted for imbibing a much greater degree of heat from the rays of the sun; and of soils, brought to the same degree of heat, some cool much faster than others. Soils that consist chiefly of a Srirr WHITE CLAY, take heat slowly; and being usually very moist, they retain their heat only for a short time. CuaAtxs are similar in be- ing slowly heated: but being drier, they retain heat longer. A BLAck soIL CONTAINING MUCH SOFT VEGETABLE MATTER, if the site and aspect dispose it to dryness, is most heated by the sun and air: all the coLouRED soiLs, especially those containing much carbonaceous matter (charcoal,) or ferru- ginous matter (iron,) are disposed for acquiring a much higher temperature than PALE-coLourReD soils. When soils are per- fectly dry, those that most readily become heated by the solar rays, likewise cool most rapidly. Moisture without fermenta- tion retards the accession of heat, and accelerates its escape. The faculty of absorbing and retaining moisture has been al- ready brought under notice. The method of detecting the pre- sence of some ingredient in the soil which the eye cannot per- ceive, and which escapes the touch when a portion of mould is rubbed between the fingers, is by having a specimen of the earth of such cubical dimensions as may be thought proper, dug out ; and finding the materials of it by various chemical tests. TESTS OF SOILS. For the common purposes of agriculture, the natural consti- * Mr. Strickland states the remarkable fact, that the great vein of chalk ter- minates in the East Riding of Yorkshire ; and beyond it northward, no chalk is found in the island. See also a Map Delineating the Strata of England and Wales, with part of Scotland, by W. Smith, 1815. ey iar i a 7 t \ 5 16 TESTS OF SOILS, | ; tution of a virgin soil, or the state of improvement which land under tillage has acquired from artificial causes, can, in the great majority of cases, be sufficiently determined by taking up portions of earth in different parts of a field, regard- ing the soil as a separate layer from the subsoil, or strata un- disturbed by cultivation ; and examining these by the common lights which persons employed in agriculture have derived from experience. But when the nature of a virgin soil is entirely unknown, no previous trials of its powers having been made ; or when a cultivated field unaccountably baffles the ordinary course of skilful husbandry, while lands constituted apparently like it make good returns under similar treatment; it is proper to have recourse to the aid which modern chemistry offers to agriculture, for a full and accurate knowledge of the grounds on which success may be expected, or the causes of failure exs plained and rectified. The instruments required for the analysis of soils are few, and of small cost:—a pair of scales, large enough to weigh a quarter of a pound of common earth, and so delicately exact as to turn when loaded with a grain ; a set of weights, correspond- ing with the same limits; a wire sieve, just coarse enough te pass mustard-seed ; a common kettle, or small boiler ; an Ar- gand lamp and stand; two or three Wedgwood crucibles 5 eva- porating basins; a pestle and mortar; a bone knife; some fil- ters, made of half a sheet of blotting-paper, folded so as to con- tain a pint of liquid, and greased at the edges. The principal tests, or chemical re-agents for separating the constituents of the soil, are: Muriatic acid (spirits of salts ;) sulphuric acid (oil of vitriol;) pure volatile alkali, dissolved in water; solution of prussiate of potassa; solution of potassa (soap ley ;) solution of neutral carbonate of potassa; succinate of ammonia; nitrate of ammonia; solution of carbonate of am- monia; solution of muriate of ammonia. Dry carbonate of potassa is sometimes wanted in fusing earths. The quantity of soil conveniently adapted for a perfect ana- lysis is from 200 to 400 grains. It should be collected in dry weather, and exposed to the atmosphere till it becomes dry te the touch. Independently of regular analysis, the specific gravity of a soil assists to indicate the quantity of animal and vegetable mat- ter it contains ; because the atoms of either are lighter than the atoms of clay, of sand, or of lime. In proportion as a soil is light, it may be presumed to be rich. Before a soil is analysed, the other physical properties of it should also be examined ; be- cause they denote, in a sensible degree, the sorts of earth in its composition, and serve to guide the order in which the chemi- cal tests are applied. Sz/zceous soils are generally rough to the touch, and scratch glass, when rubbed upon it; calcareous soils (besides effervescing with acids, a trial to be afterwards descri- ‘ ee a ee Se TESTS OF SOILS. ba Ao -bed,) when in the shape of sand, do not scratch glass ; and clay, while it is generally distinguishable by the touch, neither — scratches glass nor effervesces with acids ; ferrugznous soils are, — for the most part, of a red or yellow colour, or rusty-brown, 1. Measure or AxpsorBENT Power BY THE DIssIPATION or Latent Water.—After soils have been dried by continu- ed exposure to the air, they still contain a considerable propor- tion of water which adheres to the earths, and to the animal and _ vegetable rudiments, .in such obstinate combination, that it can only be driven off by a high degree of heat. To free a spe- cimen of soil from as much of this water as may be, without otherwise affecting its constitution, let it be heated for ten or twelve minutes over an Argand’s lamp, till its temperature at- tain 300° of Fahrenheit. If a thermometer be not used,* the proper maximum of heat may be measured by keeping a piece of wood in contact with the bottom of the dish: While the co- lour of the wood remains unaltered, the heat is not excessive: as soon as the wood begins to be charred, discontinue the pro- cess. If a higher heat were applied, the vegetable or animal matter would be decomposed, and all the following train of ex- periment be rendered illusory. _ The loss of weight in the soil thus dried should be noted, as indicating the absorbent power of the soil. Supposing the spe- cimen to have previously weighed 400 grains, the loss of fifty (or an eigth part) denotes a soil absorbent and retentive of wa- ter in the greatest degree: such a soil will generally be found to contain either much vegetable or animal matter, or a large pro- portion of aluminous earth, in which two respects this indica- ticn is equivocal; but the tests to follow will decide. When the oss is only from a twentieth to a fortieth part of the whole, the soil is but slightly. absorbent, and siliceous earth probably forms the greatest part of it. 2. SEPARATION or Gross FRaGMENTs.—Loose stones, gra- vel, and vegetable fibres, are carefully kept in the specimen un- til after the water is dissipated; for they participate, in different degrees, in that power of absorbing moisture which affects the ertility of land. After the process of heating, detach these ; by bruising the soil gently in a mortar, and passing it through the sieve. Take separate minutes of the weights of the vegeta- » bie fragments, and of the gravel and stones ; distinguishing the nature of the latter. If calcareous, they will effervesce with acids ; if siliceous, they will scratch glass; and if aluminous, _they will be easily cut with a knife, and will refuse the tests_of lime and flint. 3. SEPARATION OF THE Sanp,—The greater number of soils contain varying proportions of sand more or less granulated. It * Blements of Agricultural Chemistry, p. 112. C yay iN ee A OO asta wert, 5 ‘is necessary to scparate the sand from the impalp finely divided matters; such as clay, loam, marle, vegetable and animal atoms. To do this, boil the sifted mass in four times its weight of water: when the texture of the soil is broken, and the water cooled, alternately shake the sediment in the vessel, and suffer it to settle ; for in subsiding, the different parts will be ¥ M distributed in layers. ‘Thus treated, the coarse sand will gene- rally separate in a minute, and the finer in two or three minutes, while the infinitely small earthy, animal, or vegetable matters, will continue in state of mechanical suspension: so that by pour- ing the water from the vessel after three minutes, the sand wiil be found divided from the other substances. The other sub- . stances, with the water containing them, must be deposited in a filter, to be analysed as under 4. Meanwhile the sand is to be examined, and its quantity registered. It is either calcareous or siliceous ; and its nature may mostly be detected as that of stones and gravel, without a minute analysis. If it consist whol- ly of carbonate of lime, it will rapidly dissolve in muriatic acid, with effervescence ; but if it consist partly of this, and partly of siliceous sand, the latter will be found unchanged after the acid dissolving the lime has ceased to effervesce. This residuum must be washed, dried, and heated strongly in a crucible. Its weight is then ascertained by the balance ; and that, deducted from the weight of the whole, indicates the quantity of calcare- ous sand dissolved. 4. ANALYsIS OF THE FinELY-pivipED Matters.—The water passing through the filtre is to be preserved; for if any saline particles or soluble animal and vegetable elements exist- ed in the soil, it will be, found to containthem. Meanwhile the fine solid matter left on the filter must be collected, and dried. This is usually a compound exceedingly multifarious; it some- times contains all the four primitive earths, as well as animal and vegetable matter. To ascertain the proportions of these with tolerable accuracy, is the most difficult part of the assay. 1 Test or Lime in a Sorip State.—Of muriatic acid take twice the weight of the promiscuous soil; and dilute the acid with double the measure of water. Let the mixture remain for an hour and a half, stirring it frequently. By this time, if any carbonate of lime or of magnesia existed in the soil, they will have been dissolved in the acid; which sometimes takes up likewise a little oxide of iron, but very seldom any alumina. ML) The fluid should be passed through the filter. Then let the solid matter be collected, washed with rain water, dried under a moderate heat, and weighed. The loss denotes the quantity of solid matter taken up. i1. Test oF Inon.—Add the washings to the solution, which, if not sour to the taste, must be made so by the addition of fresh — gk’) Ca WR) LS Lis ee a a I ye aw 4/0Ou A! ae aay Ditech as eee ; (4) i yi } Hea | our) , y PA F = TESTS OF SOILS, a eG acid. The test now to be added to the whole, is some triple so- _ lution of prussiate of potassa and iron. If a blue precipitate oc- curs, it indicates the presence of oxide of iron; and more of the triple solution must be dropped in till this effect ceases. In or- der to weigh the precipitate, it must be collected and heated red. The result is oxide of iron, with perhaps a little oxide of mane ganesum. 111. Test or Lime sUsPENDED In A FLurp:—ALso or Mac- NEstA.—Having taken out ail the mineral oxide, next pour into the fluid a solution of neutralized carbonate of potassa, continu- ing to do so until it will effervesce no longer, and: till both the taste and smell of the mixture indicate an excess of alkaline salt. | The precipitate that falls down is carbonate of lime: it must be collected on the filter, and dried at a heat below that of red- ness. The remaining fluid must be boiled for a quarter of an hour; when the magnesia, if any exist, will be thrown down, combined with carbonic acid. To bring it into a state for being weighed, treat it as the carbonate of lime.* — 3 | iv. Test of ALUMINA INCIDENTALLY DISSOLVED AND PRE- €IPITATED.—If any minute proportion of alumina should have been dissolved by the acid employed in the first test, it will be found with the carbonate of lime in the precipitate obtained by the third. To separate it from the carbonate of lime, boil it for afew minutes with as much soap lye, or solution of caustic so- da, as will cover the solid matter. Soap lye thus applied dis- solves alumina without acting upon carbonate of lime. v. Measure or THE MATTER DESTRUCTIBLE BY RED- unat.—After the finely-divided promiscuous soil has been act- _ed upon by muriatic acid, the next step is to ascertain the quan- tity of insoluble animal and vegetable matter which the residue um contains. Set it in a crucible over a common fire ; and let it be ignited till no blackness remains in the mass ; stirring it often with a metallic rod so as to expose new surfaces successively to the air. The loss of weight ultimately caused, shews the quantity of sub- stance destructible by fire and air. When the smell emitted during the incineration resembles that of burnt feathers, it is a certain indication either of animal _* In case the soil be sufficiently calcareous to effervesce very strongly with acids, Professor Davy gives us a method of measuring the quantity of carbon- ate of lime, by collecting the carbonic gas expelled by the acid in a pneumatic ' apparatus described verbally in the Lectures, p. 116. This gas is to be either measured or weighed ; and it will bear the proportion of 43 to 100 to the ori- _ ginal weight of the carbonate of lime. This may be a very simpie process to an expert chemist; but it is neither so easy to describe, nor so cheap to practice in occasional experiments, as that above. In an outline like this, for popular use, it is therefore sufficient to notice it. ‘ CV et Lape K ty 26 - matter or of some substance analogous to it: on the other hand, re a copious blue flame uniformly denotes a corresponding propor= tion of vegetable rudiment. It will accelerate the destruction — of matter decomposable by ignition, to throw gradually upon the heated mass some nitrate of ammonia, in the proportion of one-fifth to the weight of the residual soil. . VI. SEPARATION OF THE PARTS INDESTRUCTIBLE BY HEAT. —The remaining parts are generally minute atoms of earthy matter, comprehending alumina and silica, combined with oxide of iron, or of manganesum. To separate these, boil them in little more than their weight of sulphuric acid, diluted with four times its weight of wa- ATEN. ' The substance keeping a solid form after this treatment, may be considered as siliceous. Let it be collected on the filter, washed, dried, and weighed. If the residuum contained any oxide of ‘iron, or of mangane- sum, they will have been dissolved by the sulphuric acid. To throw down the oxide of iron, add in excess succinate of am- monia. When this has been done, introduce soap lye, to dis-~ solve the alumina, and to precipitate the oxide of manganesum, Heat the oxides to redness, and then .eigh them. Should any magnesia and lime have escaped solution by the first test, that of muriatic acid, (which is rarely the case,) they will be found ia the sulphuric acid. Their quantities are ascer- tained by a similar process to that above. (CouRSE SOMETIMES SUBSTITUTED For “v. and vr.”—If very zreat accuracy be the object, dry carbonate of potassa must be employed as the agent; of which four times the weight of the subject must be put with it into the crucible, and heated red for half an hour. The mass indestructible by heat must then be dissolved in muriatic acid, and the solution evaporated till it is nearly solid. In this state, add to it distilled water, by which the oxide of iron, and all the earths, except silica, will be dis-~ solved in combination as muriates. The silica, after filtration, must be heated red. The other substances‘are separated as from the muriatic and sulphuric solutions above. Where'the soil to be analysed contains stones of doubtful composition, this pro- cess is well fitted to determine their character.) Sj vil. EvAPpoRATIoN or THE Dicestinc WatTer.—The wa- _ ter first used for boiling the earth as under L 3. (and which was directed to be kept for a separate trial) will contain whatever sa-_ line matter, or soluble vegetable and animal rudiments, existed — in the soil. } 4 This water must be evaporated to dryness at a heat below boiling. he If the solid matter obtained be brown in colour and inflam- — mable, it may be regarded as vegetable extract, unless in com- . rf OT LEL Wr wi 4 y TESTS OF SOILS. __ . 4 24 _ bastion it emit a smell like tiat of burnt feathers, which indi- cates animal or albuminous matter. If any portion be white, - crystalline, and not destructible by heat, it may be considered as saline im its properties. The saline matter altogether bears a _Tinute proportion to the other constituents; and as most of itis _ generally common salt, the following tests need seldom be re-, sorted to. Salts of potassa are thrown down by a solution of -platina. Sulphuric acid combined with any salt is detected ina solution of baryta by a dense white precipitate.» Salts of lime assume a cloudy appearance in a solution containing oxalic acid. Salts of magnesia cause a similar cloudiness in a solution of am- monia. Muriatic acid is discovered by forming clouds in a so- lution of nitrate of silver. Salts consort nitric acid sparkle when thrown on burning coals. ville PROCESS FOR DETECTING LARA hs oF LIME, anD PuospHate or Lrme.—Sulphate of Lime (Gypsum) is to be detected by another independent process ; on which is engrafted a method of getting at Phosphate of Lime in a separate state. First, put the residuum, with one-third of its weight of powder- ed charcoal, into a crucible: and heat the mixture red for half an hour. The mass is afterwards to be boiled in water, (half a pint to 400 grains,) for a quarter of an hour. Filter the whole : expose the collected fluid for some days to the atmosphere ; and so much gypsum as the soil comprised will be gradually depo- sited as a white precipitate. Then to separate the Phosphate of Lime from the solid resi- duum, digest upon it muriatic acid more than sufficient to satu- rate the soluble earths, Evaporate the solution, and pour wa- ter upon the remains. The result will dissolve the earthy com- pounds, and leave the phosphate of lime untouched. When Sulphate of Lime and Phosphate of Lime have been thus disengaged in a solid form, it is sometimes necessary to de- duct a sum equal to their weight from the amount of the Car- bonate of Lime; but that is only when the latter has been cal- culated by the loss sustained in solid matter, part of which en- ters into the new compounds from which the Sulphate and Phos- phate have been recovered. Ix. FoRMULA FOR REGAPITULATING THE RESULTS.— When the analysis of a soil is finished, add the quantities together ; and if they nearly equal the original portion of soil,* the assay may be confided in as accurate. Four hundred grains of a good siliceous sandy soil from a hop garden near Tunbridge, Kent, gave these results ;— Grains Water of absorption . ao! Dal ATM aa, ema noose stones and gravel, chiefly flinty BN Es iy CM Carried over, 2° 9") = 0 2 * Elements of Agricultural Chemistry, p. 120. ’ fri LNA 4 aT iv y DRA enn rl Fae --- SORRECTIVES OF SOILS. | ft Brought forward, Wy) Undecomposed ves ealy Abres ie se Wale (14, Fine siliceous sand SRSA ONE eta er ye a21y $2 (Carbonate of lime ye eT Te ee 22 & Carbonate of magnesia be eS 3) Be Matter \ dibeieng by peat chiefly vegetable - - - 15 2. 3) Silica - «|. «0a a 3*3 \ Alumina wae A ey i pm cl be ON Ua a) er 23 J Oxide of iron Ws oan 5 28 Soluble matter, principally eo common salt and 'vepetabile extract” , 3 Zo \ Gypsum PC Te ad iy hy - - - 2 Loss ° . 21 ———os 400 x. PoruLAR APPLICATION OF DETACHED STEPS IN THE PRo- crss.—The assay may be very much simplified, when the inqui- ry is confined to one leading object. Thus, if it be merely wish- ed to know, whether a soil contain already so much lime as to make it inexpedient to bring on lime as a manure, it will be enough to put the specimen into a dish, and to pour upon it a quantity of muriatic acid : indeed when no other experiment is to be grounded on this trial, good white-wine vinegar may be employed. If the soil immersed in acid effervesces strongly, it is sufficiently charged, or perhaps overcharged, with lime. In a similar way, one or two essential questions may be Sometimes - solved by resorting to any of the other tests, either alone, or two or three connectedly, in a different order from that which has ‘been set down. CORRECTIVES OF ILL-CONSTITUTED SOILS. The following are simple and efficacious correctives of some bad ingredients in soils, or the excess of some good constituent}; the presence of which frequently disappoints even the skilful cultivator, when either the true cause is not suspected, or an ap- propriate remedy is not known. 1. A farmer witha great portion of common skill is often baf- fled by Iron in 117s actp comBinaTions. If on washing the specimen of a sterile soil, it is found to contain the SALTs oF YRON, SULPHATE OF IRON, or any AcID MATTER, it may be ameliorated by a top-dressing of quick lime; which converts the sulphate of iron (copperas) into a manure. 2. If there be an Excess oF PURE CALCAREOUS MATTER (CHALK OF Lime) in a soil, its constitution may be improved by turning in, in a green state, some of those vegetables which pos- sess the greatest quantity of acid; also by the application of sand or of clay, witha small ep ag of oxide of iron (blacksmith’s sweepings) not exceeding J, part. The same object may be ob- tained by irrigating with ine calybeate water (water containing tte CORRECTIVES OF SOILS. ss) - iron,) or by the addition of peat containing vitriolic (i. e- sul- - pharic) salts ; both which are calculated to turn lime or chalk - into gypsum.* See under VII. 5. why gypsum is sometimes beneficial and sometimes not. a _ 8. When an Excess oF CARBONATE OF LIME (charcoal uni-. ‘ted to lime) requires the quality of the soil to be modified, gyp- sum applied as a manure, also oxide of iron applied as a cor- rective, seems to produce the very best effects. Carbonate of lime is mild lime in combination with charcoal absorbed from decay- ed vegetable or animal matter. The diversified effects of lime as a manure are explained under VII, 1. 4, Soils REDUNDANT IN SAND are benefited by a top dressing of peat or other vegetable matter, or of decayed animal matter, or by a mixture of clay. Also, if the sand be not calcareous, by marle. _ 5. An Excess oF VEGETABLE MATTER is to be removed ei- ther by burning, (See III. Paring and Burning,) or by the ap- plication of earthy materials. The fundamental step in the im- provement of peat land, or a bog or marsh, is draining. Sort BLACK PEATS, after being drained, are often made productive by the mere application of sand or clay, as a top dressing : sand is greatly to be preferred. When Peats are Acib, or contain FERRUGINOUS SALTS, calcareous matter is absolutely necessary in bringing them into cultivation. When they asounD IN THE ROOTS AND BRANCHES OF TREES, the wood must either be grub- bed up and carried off, or destroyed by burning ; so when the face of peat is incumbered by living plants conTAINING MUCH woopy Figre, and therefore not proper to be ploughed in the ground, the field must be cleared by one of the same methods.}+ 6. Where there is a REDUNDANCY or cLay ina soil, (and if the quantity of clay exceed one-sixth of the general mass, it is desirable to reducé the proportion,) one of the best dressings which can be applied is a mixture of sand and mild lime; the rubbish of mortar containing both these materials, is an excel- lent thing to improve the texture of a clayey soil. Clay appears to receive no improvement from lime alone. Sea-sand may be used alone with good effect. It would be also highly beneficial ‘to introduce as much fermented dung or decayed vegetable mat- ter as would entitle the land to the denomination of a loam, II. By Draining. No perennial crops, and but few annual plants, can be successfully cultivated where the land is exposed to winter floods, or where the subsoil is rendered wet by under- springs, or by heavy leakage from neighbouring pieces of water lying higher and imperfectly banked off. The importance of * Elements of Agricultura! Chemistry, p. 141, 226. + Ibid. p. 142. ; draining peat land has been adverted to under L. be “Where open drains would be unsightly or inconvenient, as in the inte- rior of a domestic garden, or ornamented ground, a paved brick drain is in the end cheaper than a rubble drain, because the latter is liable to be soon choked by the roots ot trees. | Ill. By Paring and Burning. It is obvious, that in all ca- ses the process of BuRNING must destroy a certain quantity of vegetable matter; and it must principally be useful where an excess of this matter renders the soil too rank. It must be of eminent service in reducing to charcoal, or wood ashes, a great accumulation of woody fibre already overrunning the field ; for woody fibre is very slowly reduced to the state of vegetable mould, if left to the process of a natural dissolution: nor is it very rapidly reduced by lime or other solvents artificially ap- plied. Burning likewise renders clays less coherent; and in this way greatly improves their texture, and causes them to be more permeable to water,* and consequently. less retentive of it in stagnant masses. Another cause of the unproductiveness of cold clayey adhesive soils, is, that the seed is coated with mat- ter impenetrable to air.t When clayey or tenacious soils are burnt, their power or tendency to absorb water from the atmos- phere i is diminished in the proportion of 7 to 2; and they are brought nearer to a state analagous to that of sands; the parti- cles are less adhesive, and the mass less retentive of moisture. Thus the process of burning, properly applied may convert a matter that was stiff, damp, and in consequence cold, into one powdery, dry, and warm; altogether more fitly constituted as a bed for vegetable life. The great objection made by specu- lative Chemists to paring and burning is, that the animal and vegetable matter in the soil is diminished :—But where the tex- ture of the earthy ingredients is permanently improved, theré is more than a compensation. ‘T'o meet the objection still more directly, where an excess of inert vegetable matter is present, the destruction of a part of it must be beneficial ; and the car- bonaceous matter in the ashes may be more useful to the crop, than the unreduced vegetable fibre, of which it is the remains,$ could have been. The most speedy way of bringing under tillage a meadow overrun with rushes is; first to drain it, and then to pare off a thick turf and burn it. The cases in which burning must incontestably be prejudi- cial, are those of sandy dry flinty soils containing little ani- mal or vegetable matter: here it can only be destructive ; for * Elements of Agricultural Chemistry, p. 22. t Ibid. p. 149. + Thid. p. 234. hw Re! t decomposes that constituent which is already below the mini- mum proportion, and on the presence of which, in a limited de-- _ + gree, the productiveness of a soil depends.* - in cA _% Burning without fire.’ A new method has lately been discovered of substituting quick lime for fire ; and experiments thade upon it before the Workington Agricultural Society gave general satisfaction. The lime in its most cacstic state, fresh from the kiln, is laid upon the vegetable surface to be consumed ; _ and before it is weakened by exposure to the air, water, just in sufficient quantity to put it powerfully into action, is applied, This fierce compound will not only consume the vegetable co- vering, but affects the clay, or other upper stratum, as if it had been in contact with fire. It supersedes the trouble which has hitherto attended burning; and in respect to poor soils which would be improved by the two distinct operations of burning and liming in the common mode, it bids fair to bring them sooner on 2 par with those of superior quality. it IV.. By Turning-in Green Crops as Manure.—This is di- rectly opposed to Burning Turf, in regard to intention and ef- fect ; and is particularly serviceable where the basis of vegeta- ble mould is to be augmented, being an extension of the prin- eiple on which Paring Turf without Burning is resorted to.— When Green Crops are turned into the clod, besides enriching the staple with nutritive matter, they promote the fermentation and decomposition of woody fibre buried near the surface ; and which is a useless incumbrance in an undecayed state. “When GREEN crops are to be employed for enriching a soil, they should be ploughed in, if possible, when in flower, or at the time when the flower is opening ; for in this stage, they contain the largest quantity of soluble matter. Green Crops, pond-weeds, the paring of hedges or ditches, or any kind of fresh vegetable matter not. woody, require no preparation} to be fitted for manure. When op pastuRgs are broken up for til- lage, not only is the soil enriched by the death and slow decay of the plants which have previously deposited soluble matters in the clod; but the leaves and roots of the grasses (vegetating just before the change of culture) afford saccharine, mucilagin= ous, and extractive matters, which become immediatelu the food of the crop ; also the gradual decomposition of the grasses af- fords a supply of vegetable mould for several years.” _ After giving the substance of Sir H. Davy’s theory on any specific subject in agriculture, it will not be often necessary to incur the hazard of questioning some incidental deduction from the system ; .because the principal branches of his theory are so ‘consonant with experience, that they incontestibly contribute sound and intelligible principles for applying more extensively, * Elements of Agricultural Chemistry, p. 22, 4 Ybid, 197. D “Ny aN Pees f the practical farmer had arrived, by the empirical course of laying different ingredients on land without knowing their precise operation, were previously few and limited, or their utility doubtful. But in regard to the efiect of VEGETABLE MATTERS as ‘ma- ’ nures, there is a vein of doctrine pervading the theory of this great chemist, which seems to be taken up independently of ex- paxience, and without calculating all the principal relations be- lotfging to the subject :—w hich doctrime ist that to bury vegeta- ble manure without’ fermenting, and leave it gradually to de- compose in the soil, will prolong its fertilizing power for several seasons. So it will :—but what will be the intermedi- ate state of the soil? Surely the capacity of the land for grow- infy healthy plants cannot be equal to that of a clean soil where Ne manure Is not applied till it is ready to afford nutriment. This part of the theory is in opposition to the practice of Doig turf before it is turned into the soil, or of waiting till it has become rotted before a new crop is introduced. ‘There will be several occasions of adverting to this principle again; and of viewing every side of it as it may catch different lights in different positions, particularly under Sect. V. By Fallow- ing, and the head ManaGement or MAnvRE FROM THE HomnsTrap. V. By Failowing.—Sir Humphry Davy seems to under-rate the utility of fallowing, and to be disposed to recommend the non-fallowing system. The following is the substance of the observations occurring in different parts of his Work on this subject. (1st.) “ The chemical theory of fallowing is very simple. Fallowing affords no new source of riches to the soil. It merely tends to pro- and with more eereaitl effect, entire cfakaes of eae By. comimand of the cultivator where the resources to which. duce an accumulation of decomposing matter, which in the com-— mon course of crops would be employed as it is formed; and it is scarcely possible to imagine a single instance in which a culti- vated soil can lie fallow for an entire vear with advantage to the farmer. The only cases where this practice is beneficial seems to be in the destruction of weeds, and for cleansing foul soils. * “ The benefits arising from fallows have been much over- rated. A summer fallow, or a clean fallow, may be sometimes necessary in lands overgrown with weeds, ‘particularly if they are sands,—which cannot be pared ‘and burnt with advantage : but it is certainly unprofitable as part of a general system of | husbandry.”’} (2dly.) “ It has been supposed by some writers, that certam * Elements of Agricultural Chemisty, p, 22. t Ibid, 239, . FALLOWING. Principles necessary to fertility are derived from the atmos- phere, which are exhausted by a succession of crops, and that i these are again supplied during the repose of the land, and the , exposure of the pulverized soil to the influence of the air: but this, in truth, is not the case. The earths commonly found in ‘soils cannot be combined with more oxygen; none of them will unite to azote ; and such of them as are capable of pile carbonic acid, are always saturated with it on those soils . which the practice of fallowing is adopted: ‘The vague Tice ; opinion of the use of nitre, and of nitrous salts in vegetation, seems to have been one of the principal speculative reasons for the defence of summer fallows. Nitrous salts are produced during the exposure of soils containing animal and vegetable remains, and in GREATEST ABUNDANCE IN HOT WEATHER: but it is PROBABLY by the combination of azote, escaping from those remains, with oxygen in the atmosphere that the acid is formed ; and at the expense of an element which would other- wise have been converted into ammonia; the compounds of which, as is evident from what is stated under VIII. 2, are much more efficacious than the nitrous compounds in assisting vegetation.” * (3dly.) “* When weeds are buried in the soil, by their gra- dual decomposition they furnish a certain quantity of soluble matter: but it may be puuBTED, whether there is as much use- ful manure in the land at the end of a clean fallow, as at the _ time the vegetables clothing the surface were first ploughed in. Carbonic acid gas is formed during the whole time by the action of the vegetable matter upon the oxygen of the air ; and the greater part of it is lost to the soil in which rt was formed, and ( dissipated in the atmosphere. *“ The action of the sun upon the surface of the soil tends to disengage the gaseous and the volatile fluid matters contained in it; and heat increases the rapidity of fermentation: and in the summer fallow, nutriment is rapidly produced at a time when no vegetables are present capable of absorbing teh oapae (4thly.) “ Land when it is not employed in preparing food for animals, should be applied to the preparation of manure for plants ; and this is effected by means of GREEN CROPS, in con- sequence of the absorption of carbonaceous matter from the carbonic acid of the atmosphere. In a summer’s fallow, a pe- riod is always lost in which vegetables may be raised, either as food for aninals, or as nourishment for the next crop ; and the texture of the soil is not so much improved by its exposure as in winter, when the expansive powers of ice, the gradual dis- solution of snows, and the alternations from wet to dry, tend to pulverize it, and to mix its different parts together.”’ * Elements of ARE ona Chemistry, p. 240. + Thid. thid. 28 iF PALLOWING, The Reader has now before him the arguments divente by Sir H. Davy against the practice of fallowing, as part of a ge neral system of husbandry. But cannot some of the above objections to the giving of a. periodical rest to land after an exhausting crop be obviated ?_ and are not the benefits of a summer fallow, when admitted te be necessary, in some respects undervalued ? ? In the first place, this eminent philosopher observes, that fal. lowing “* MERELY tends to produce an accumulation of decom- posing matter, which in the common course of crops would be. employed as it is formed.” “But this accumulation of decom- posing matter is alone a great acquisition ; it is in many cases the precise restorative wanted to keep up the proportion of ve- getable mould necessary to fertility, Supposing the milder course of crops to employ the decomposing matter as it is formed,—how are plants which depend still more on the nutri- ment lodged i in the soil, to be grown in full crops, where the quantity of manure is ‘limited by local circumstances, unless the elements of vegetation are allowed to accumulate for a sea- son, at periods adjudged proper by a manager acquainted with the power of the soil and the course of crops? Secondly, in opposition to the idea that certain principles ne= cessary to ‘fertility are derived from the atmosphere, Sir Hum- phty enters on a speculative train of reasoning,—against which it would be presumptuous to appeal, had he offered a positive conclusion as a great chemical authority ; but some of the as- sumed data—such as that the “ earths commonly found in soils caunot be combined with more oxygen’’—seem to skirmish with the conciusion [“ Nitrous salts”... to the end of the para- graph ;|—nor has the “ vague ancient opinion of the use of nitre and of nitrous salts in vegetation” been subverted or discoun- tenanced by the experiments of modern physiologists, many of whom have found that plants will grow in nitre alone, which is more than the ancient opinion requires in its support. And as to the final inference,—‘ but it is PRopaBLy by the combina-_ tion,” &c. the uncertainty disclosed in the word “ pr obably,” deprives the argument of all decisive effect in a practical point of view for although the Professor is acquainted with the ope- ration of gases as Far perhaps as experiment will ever trace it, the manner in which nitrous salts are produced in soils contain- ing animal and vegetable remains, is but guessed at by him, and not explained to us with the authori ity of certain knowledge. Thirdly, this distinguished Chemist, after virtually admit- ting, that the weeds which were overrunning the land must en- rich it by being buried in its bosom, further observes :-—“* But it may be pousrep, whether there is as much useful manure in the land at the end of a clean fallow, as at the time the vegeta-_ bles clothing the spr were first ploughed i 1s’. Jos OCGe eae | fe, , ” * 5 | » ‘ } i U , i le, , FALLOWING. 29. To this speculative objection the answer must necessarily fake a speculative turn. : If there be less manure in the land at the close of a fallow, the quantity lost must have escaped in the shape of vapour, and been dispersed in the atmosphere. It may be worth while to “inquire how far this is to be estimated as a loss ¢ In opposition to the theory of Sir Humphry Davy on this point, it is quite consistent with good logic to suppose, that whatever escapes from the dissolving mass of a dead plant in the form of vapour, and does not fall down to the earth by con- densation, is easily and most naturally taken up by a new grow. ing plant from the atmosphere, through the leaves; that is to gay, whatever has a tendency to fly off into the air is to be re- “covered by communication with the air. On this subject the theory of the author of these remarks is as follows ;— . To form the bulk of a growing plant,—certain SussTANcEs comprehended under some of the descriptions of matter com- mon to vegetables, and which appear on analysis to be combined differently in different species, are taken up by the roots from the soil, and by the leaves from the air, through the medium of congenial fluids: in succulent plants a greater proportion of food is received by the leaves than by the roots, so that even the bulk of the plant, or the basis of the sap, is in such kinds increased chiefly by derivations from the air. To imbue a common insipid basis with those distinguishing peculiarities which make different species growing in the same soil differ in scent, flavour, and the qualities which are salutary or pernicious in food and medicine,—certain Spectric Essen- ces, or volatile aériform atoms, invisible either from being co- lourless or minutely divided, are taken up entirely by the leaves ’ from the air; the character of the plant having been originally fixed by a portion of the peculiar essence being lodged in the seed so as to attract to it only volatile particles of its own na- ture.* Hence in mixed masses of manure, the manure may be con- sidered better adapted for general purposes, when the volatile properties peculiar to specific plants and to animal bodies have escaped, and when the residuum is nothing more than the mat- ter common to vegetable and animal bodies. It may seem to be a loss, that the gaseous essence, escaping into the atmosphere, is dispersed over an immeasurable region of air, and carried by winds over the face of the earth, instead of being retained for the enrichment of a particular field. To * This theory will go a considerable way towards affording a solution why the blossoms and fruit of a graft should preserve their distinguishing peculiari- 4ies, unaltered by connexion with the stock, rn 80 | 3 FALLOWING, | Sie 7% : me , mA . By -. this it may be answered, that the gases of which the air is con- stitued—oxygen, azote, and carbonic acid gas—though differing in their specific gravity ar rather levity, are found to be com- bined in any cubical quantity of air in a proportion which ne- ver materially varies ;* and it is quite reasonable to suppose, that the volatile salts or spirits, or aromatic principles, which constitute the essences of plants, are distributed equally over the atmosphere by the same law. The quantity of volatile essence floating within reach of the attraction of an individual plant must, ‘indeed, be allowed to be evanescent even to the confines of no- thingness, when the transparency of the air is considered, and the multiplicity of different essences of which infinitely small divi- sions are supposed to be floating in it. But if,on the other hand, we advert to the elastic nature, of the air, and the property which it is found to have of always preserving its natural equi- librium, the most scanty provisions of volatile food in the vici- nity of a plant is abundance. Thus, suppose a plant to take up carbonic acid gas with great avidity ; although the proportion of carbonic acid gas is extremely small, yet the plant cannot drink up the quantity in immediate contact so fast, but the same quan- tity will be constantly, preserved in the air surrounding it; for gas of the same nature is incessantly pressing into the temporary void where the interchange of natural air is unrestricted. The supply of a peculiar essence to plants, by the medium of the common air, may be rendered sufficiently ample by obedience to the same law. It may therefore be one of the benefits of a fallow, to lose every thing which can escape by a free exposure of the putrefy- ing remains which promiscuously accumulate in a soil. On the hypothesis which has just been sketched, the objec- tion of Sir H. Davy, that “* the action of the sun upon the sur- face of the soil tends to disengage the gaseous and the volatile fluid matter that it contains, and heat increases the rapidity of fermentation,”—may be enlisted among the arguments in favour of a summer fallow. In cases where a restorative course is de- sirable, the objector also becomes an ally who urges, that “ in — the summer fallow nutriment is rapidly produced at a time when no vegetables are present capable of absorbing, it.” _ Fourthly, with regard to the superior utility of ploughing in Green Crops, as recommended in the Elements of Agricultu- ral Chemistry, instead of a fallow :—There can be no difference of opinion where the land is poor, or exhausted, without being foul; that is to say, when it wants recruiting with manure, but not cleaning of root-weeds to the full depth of the soil. Plants which — quickly decompose, such as the lettuce, are most conducive to — * Ina given volume of air, their proportions are usually found to be : Oxygen Ziv. » } } 1 y : Fos? azote =48, ; carbonic acid gas 4. max. -i, min. Bee: } FALLOWING. | 34 the object of exciting a fermentation in fibrous woody remains as well as enriching the land. This subject has been already touched under Sect. IV. To return tothe question of fallowing. It is merely to dis-. _ embarrass the practical manager, that so much has been said by way of theory against an hypothesis on non-fallowing, which is made to depend on assumptions from chemical principles too little capable of proof trom experiment to be safely adopted in this branch of agriculture. Some of the incidental statements, in the above abstract from the Professor’s Lectures, are decidedly adverse to practical maxims in which most farmers, and the majority of writers on husbandry, including the Reports from Agricultural Societies, concur ;—the statements, for example, that ‘ sands are benefited by a summer fallow more than clays ;’ and that the ‘ land is not richer at the end of such a fallow than it was before.” On the contrary, the conclusion to which the registered courses of pro= fitable husbandry lead, is very much like the following sum- mary. i diana is uniformly recruited during a fallow : this is pro- ved by the circumstance, that, in all soils, @ much less quantity of dung is necessary after a summer fallow ; and on some lands none is wanted; nay, the experienced Cally is of opinion, that dunging naked fallows is in many cases better dispensed with, and has often, in tolerable loams, made the crop to fail. 2. Clays are unfit for green crops, the substitute for a sum~ mer fallow ; and hence are necessitated to adopt the latter, in rotation with white crops.* A winter fallow merely is, indeed, an excellent thing in light grounds, and as a preparation for spring wheat; but it will not do with clays, which require a thorough drying and pulverizing, before they can profit by the falling juices, which would only render the earth more hard and ‘compact. A summer fallow is, therefore, more proper for this soil.+ 3. Light soils only can dispense with fallows. The ques- tion therefore is narrowed to this compass : Whether the benefit _of a summer fallow, on a sandy or other light soil fit for green ‘crops, is equal to the loss of a year’s rent, or to the difference between the profit of a green crop and the rent for one year _ paid on a naked fallow? The general conclusion is,—that it is not; and that a summer fallow for light soils is teo costly. By a rotation of crops, every ingredient in the manure ap- plied is successively turned to profit; for those parts of i¢ which are not fitted for one crop remain as nourishment for another. : ; f eter by the President of the Workington Agricultural Society, dated Noy. 0, 1814. + Philosophical Magazine for Jan. 1815. No. 1, p. 12. . in AYN 02 FALLOWING« ¥ > ‘* ‘ Different soils require a different rotation, and the practice of one district afford no absolute rule for another. Local cireum- stances will always influence the course of crops; yet a survey of some of the rotations, which after long trial are found to be repeatedly beneficjal on the principal sorts of land, tends to en- large the resources of farming ; and if brought from a distant part of the island, the chance of a beneficial exchange of inifor- mation, in some respects new, is increased. ‘The following communications are gathered from a voluminous work, entitled General Report of the Agriculture of Scotland, published under the superintendance of Sir John Sinclair, Benerit or Green Crops.—* The introduction of Turnips and Clover has been the means of rendering productive those inferior soils which it was impossible to cultivate under the old system of successive corn crops. Even on land of a better quality, the crops which succeed these are so much more abun- dant, that it is probable as many bushels of corn now grow on the half of a given extent of ground as were formerly raised: on the whole. In this view alone, almost the whole value of the turnips and clover may be said to be a clear gain. allow has been banished from all dry soils by turnips ; and where land is laid down to pasture, one acre of clover and rye-grass will fatten more cattle than could barely exist on ten acres left full of weeds to be casually sown, after several years, with natural prasses. 7 “« When turnips were first introduced on farms, and for some time after, the most common application of them was to the fattening of cattle. Sheep did not then form any important part of the stock of arable land: but on light soils the full be- nefit of this crop was not obtained, until it had become the practice to consume the greater part of the crop on the ground by sheep. The poorest sandy soils seldom fail to yield an abun- dant crop of corn after turnips thus consumed on the ground, ‘They are thus at once manured and strengthened in the sta le. “ On dry loams, the best practice is a medium between the old and the new; and the crop is divided between the sheep: and the fold-yard, by drawing off and leaving a few ridglets- alternately. A) “The vast addition made both to the quantity and the qua- lity of the dunghill, by the consumption of green clover and turnips, powerfully recommends them ; and turnips accordingly are cultivated for this very purpose, on soils but little adapted to their growth as an edible root. When grown on clayey soils, the wholg crop is still carried to the fold-yard, for the object of converting the haulm into manure. } «So the best mode of consuming clover and rye-grass is te pasture it, especially on thin dry soils; compared with whick = the mode of reserving the entire crop for hay is very unprofita- or oats. —4. Clover and rye-grass; one moiety of the farm be ble. “ On lands less fit for pasturing, deep loams and clays, soi/- _ing is resorted to. A considerable portion of the grass is cut } pee for horses and milch cows; and in some instances, both ) r rearing and fattening of cattle. This economical use of the grass in the homestead augments and enriches the dunghill.” ROTATION WITHOUT A SUMMER FALLOW. neh, ‘ “ The most common rotation on the best dry soils is one of a four years. 1. Wheat or oats (assuming the previous crop to have been an artificial grass.)—2. Turnips.—3. Wheat, baricy, —— ing under green crops, and the other under white crops. But on siliceous sandy soils (flinty sand being the abounding ingre- dient) it is necessary to retain the clover and rye-grass division ‘for some years in pasture, unless more manure is applied to such land than can be returned from its own produce.” ROTATIONS WITH A FALLOW. “ On clayey loams the rotations are more varied. On ome clays, beans is the best relieving succession crop; and althoug it cannot be proposed as a perpetual substitute for a summer fallow, in alteration with wheat or any other exhausting culmi- ferous crop,—yet when drilled, and hand and horse-hoed, beans supersede the necessity of fallowing oftener than once in a rotation of six or eight years. Wheat and beans have been taken alternately for a series of years, even as many as eight, on the best soils; but the most frequent courses are of four and six years. The four years’ course is renewed in this order: 1. Fallow; 2. Wheat; 3. Clover; 4. Oats. The six years’ course revolves, with nice adaption to every crop, thus: 1. Fallow; 2. Wheat; 3. Clover and Rye-grass; 4. Oats; 5. Beans; 6. Wheat. Or the six years’ rotation is some- times varied thus: 1. Fallow; 2. Wheat; 3. Beans; 4. Bar- ley or Oats; 5. Clover and Rye-grass; 6. Oats: but by this arrangement the land is neither so clean, nor so well pulverized, as it should be in preparation for clovers. On clayey soils a gomplete fallow is considered as the basis of every profitable ro- tation crop by the most judicious farmers of Scotland; and a a according to their concurring experience, on wet cohesive soils, however good the course of tillage, no trials, made upon a large scale, to postpone a fallow for more than eight years, have hi- - therto been successful in that part of the island.” Some of the Papers in the above-mentioned General Report, which record this result, allude to the climate as being wet. E FALLOWING. 1a 4 eae ; , ; i ! Mie ia _and humid for a greater portion of the year than in most parts — of England; and in some degree attribute the failure, with — them, of the non-fallowing system to that cause. But having no system to manufacture for universal and perpetual applica- tion, without regard to the quality of the land, or the local re- sources for manure,—comprehensive views, a candid indepen- dence of theory, and an exact balance of the adventure, and returns under both methods, may have a greater share than the climate in their decision. ; Indeed it would be easy to multiply quotations from intelli- gent writers on this side the Tweed, the tenor of which agrees with the above, both in the inclination to dispense with fallow- ing, as far as it can be done with profit, and in the admis- sion that on certain lands a periodical fallow conduces to eventual gain. Very striking circumstances are connected with the Letters on Agriculture, from which we are going to borrow almost the counterpart of the above. First, these Letters are not behind the intelligence of the present day, though written five-and- twenty years ago; for rejecting some of the speculative notions which were then in fashion, the writer took at once the tenable ground to which experimental agriculturists have in general reverted. Secondly, they are attributed to the pen of His Majesty George the Third ;—a king who, though placed by afflictions beyond the reach of flattery, is still praised and revered by his people.* t / Extracts relating to RovaTions wiTHouT FaLtow. «The dispute which has lately arisen on the subject of sum~- mer fallows has made me secretly wish that Mr. Ducket, the able cultivator, of Petersham in Surrey, would have communi- cated his thoughts not only on that subject, but would have be- ’ nefited the public by a full explanation of that course of hus- bandry which has rendered his farm at Petersham, which has been now above nineteen years in his hands, so flourishing, though his three predecessors had failed in it.” ‘“‘ His course of husbandry seems to be the employing clover, — ‘turnipsg and rye, as ‘fallow crops, and as intermediate ones be- tween wheat, barley, oats, and rye; changing them according to the nature and quality of the land.”—Letter dated 1st Jan. 1787. _ * He would in general reject the practice of FALLOWING on light soils; as feeding-crops are better,—from the cattle, while * Mr. Young had the honour of giving them to the public in his Annals of Agricultue. 7th vol., to whom they were sent with all the exterior marks of an ordinary correspondent : they were subscribed “ Razea Rosinson,” and dated from Windsor. FALLOWING. : ih OD" _.gonsuming the crop, treading the soil, and rendering it more _ compact and firm, which a light soil requires... . Besides, this __ enabies the farmer to keep a larger stock of cattle, which increases — his quantity of manure.” __ * Phus his land, although never dormant, is continually re- plenished with a variety of manures, and thus unites the system of continued pasture with cultivation.” —Letter dated 5th March, we 1787. Extract relating to WintER Fatiows. It is to be premised that the texture of some lands gives them a middle nature between light and heavy; or else from local causes: there is no dependence that they can be kept sufficiently __ dry in winter for a feeding-crop. “ Many soils may be impro- / ved by winter fallows. This may be practiced by ploughing immediately after the grain crop is off in a dry season; and by being well water-furrowed during the winter ; and by proper dressings in the spring: but Mr. Ducket does not think this method equal to a feeding-crop of rye, turnips, or tares.”—Let- *** ter dated 5th March, 1787. ¥ Extract relating to SUMMER F aLtows. The joint effect of this and the preceding passage is the more remarkable, because the Editor of the Annals of Agriculture appended to the first Letter the Note which is exhibited below.* The note bespeaks the echo of a preconceived opinion: but his Correspondent had a mind independent of that system which would invert, instead of modifying and augmenting, the “ ga- ; thered wisdom” of a hundred generations. This reply is a pointed correction of the mistake in regard to Mr. Ducket. “© He thinks fallows necessary for sTRronc soils, as the clods of the earth cannot be well broken to pieces without being some- - time exposed to the air.”—Letter dated 5th March, 1785. As in gardens the land can be kept clean by the hoe, and the renovation by manure is more under the power of the cultiva- tor, a winter fallow is in most cases sufficient, VI. By Irrigation.—hrrigation is often found to be beneficial under two different kinds of circumstances; being resorted to with different intentions : *«__This in- sulated observation is certainly not enough to support the prin-_ ciple laid down by the Professor. As the water is reduced in depth, in the course of its subsiding and evaporating, there must happen many occasions on which the grass would lie al- ternately in shallow water, and alternately in thin ice, partly covered and partly exposed, and ready to dissolve as soon as any heat acts upon the moisture. {It concerns the practical farmer who has meadows which he can either float, or keep dry, to decide by close personal exami- nation, in what manner grasses not aquatic are affected bv lying~ under water during the frosts and other vicissitudes of winter: of this the state of the grass at the subsiding of the water in spring, and the weight of the crop, is the proper criterion.} The Professor says in another place ; ‘“* When land has been covered by water in the winter, or in the beginning of spring, the moisture that has penetrated deep into the soil, and even the subsoil, becomes a source of nourishment to the roots of the plant in summer; and prevents those bad effects that often happen to lands in their natural state from a long continuance of dry weather.”{ The alluvial matters which the water may have diffused through the veins of the land is undoubtedly be- neficial: but, were the water which has conveyed them to stag- nate in the subsoil, it would be more pernicious to most plants than the droughts of summer. We now come to some other communications by this distin- guished Chemist ; the substance of which may be given with- out protest or comment as principles consistent with experience —although they are placed on an original foundation, which enlarges the sphere in which irrigation may be safely applied, “ When the water used in irrigation has flowed over a calca- reous bed, it is generally found impregnated with carbonate of lime; and such water tends, in that respect, to ameliorate a soil in proportion as any of the modifications of lime and charcoal | were deficient: but where these are already in excess, water charged with a limy sediment should be withheld ; while wa- * Elements of Agricultural Chemistry, p. 259. + “ Should the frost set in when the water is on the land, so that some spots _ should be covered with ice for some days, the spot so covered with ice will be of a darker green, and appear more healthy in the spring than the rest of the field. But when they come to mow the hay, the crop will be considerably less than that on the other parts of the field that were not covered with ice.’ On Watering Meadows in Brecknockshire. Report by Mr, John Clark to tlie Board of Agriculture, 1794. $ Elements of Agricultural neni p. 238, ~ 38 APPLYING EARTHS AS MANURES. shales . ve Aaa ‘ter impregated with sand, clay, gypsum, or particles of iron, would be beneficial. ae ey « Common river water generally contains a certain portion of the constituents of vegetables and animal bodies; and after rains this portion is greater than at other times: it is habitual- ly largest when the source of the stream is in a cultivated country.* _ “ In general, those waters which breed the best fish are the best fitted for watering meadows ; but most.of the benefits of irrigation may be derived from any kind of water—provided the soil be not already overcharged with the prevailing ingredi- ent in the deposit left by the water ; and provided, on the other hand, that the matter of the soil and the matter of the depo- sit are not pernicious when combined. ‘These are general prin- ciples: 1. That waters containing ferruginous impregnations (particles of iron) tend to fertilize a calcareous soil. 2. #er- ruginous waters are injurious on a soil that does not efferyesce with acids, which is one of the tests of the presence of lime. 3. Calcareous waters, which are known by the earthy deposit they afford when boiled, are of most use on siliceous soils, or other soils containing no considerable proportion of carbonate of lime. Supposing the farmer to have a complete command over con- tiguous water containing a suitable alluvial deposit, he may render a cultivated level, which requires rest and a cheap ma- nure, extremely productive with comparatively little labour, by irrigating on the above principles. VII. By applying Earths as Manures.—When any decom- posed mass of stone or earth is laid upon or turned into the - ‘cultivated clod, with the object—either of furnishing a soLVENT to the remains of animal or vegetable matter which encumber the soil by their slow decay, or of enriching the land with some substance which is apparently taken up by specific plants as Foop ; then the earthy matter is applied as manure. ‘This is a distinct province from that of merely applying earths to mend the texture of the soils as under I. But sometimes the two designs will coincide. Closely connected with the theory of ~ manures is the inquiry, What is the true food of plants? “‘ The chemistry of the more simple manures, the manures which act in very small quantities—such as gypsum, the alka- ‘ lies (which include potash and soda,) and various saline sub- ystances—has hitherto been exceedingly obscure. It has been generally supposed, that these materials act in’ the vegetable _ economy in the same manner as stimulants in the animal econ- omy, or perhaps in some relations as solvents; but that in ei- ther case they merely render the common food more nutritive. * Elements of Agricultural Chemistry, p. 238. tT dbid, 239. ON THE FOOD OF PLANTS. 39 _ It seems, however, a much more probable idea, that they are actually a part of the TRUE Foop of plants, and that they supply that kind of matter to the vegetable fibre which is anala- gous to the bony matter in animal structures.”’* The probability: that Sir H. Davy has assigned to these substances their true office in vegetation, is much heightened by the earthy matters afforded by. different plants on analysis. On a similar principle, the benefit of a small proportion of shell marl, in the compost for the pine apple, is accounted for in Abercrombie’s “ Practi- cal Gardener.” } The epidermis of the rattan is stated to contain a sufficient quantity of flint, to give light when struck by steel; and some small proportion of minutely pulverized flint exists generally in the epidermis of hollow stalked plants, where it is of great use in serving as a support, and seems to perform an office in the feeble vegetable tribes analagous to that of the fine thin shell by which many insects are defended. As a prelude to a survey of the effects of different earths as manures, it may be serviceable to glance at those constituents in the kingdom of nature, which appear to be the chief agents in vegetation. Before the true constitution of Water was known, some phi- losophers and speculative horticulturists had supposed, that all the products of vegetation might be generated from water; an opinion which practical experiments have shown to be falla- ‘cious. This ancient error, and the revival of it by several eminent physiologists in the 17th and 18th centuries,t was founded on correct observations, in regard to the following points :—1. The presence of moisture is necessary to germina- ‘tion, 2. Water is the vehicle of various particles of nourish- ment derived both from the air and from the soil; and no ma- nure can be taken up by the roots of plants unless it is present. 3. Various vegetables, a greater number than can be easily na- med, have been found to grow vigorously with the roots in con- tact with water without earth. In the same manner, the existence of air-plants,—the misin- terpretation of various phenomena observed in experiments on * Elements of Agricultural Chemistry, p. 19. ¢ Hor-nouse, Pinery, p. 601. _ The first edition of the “ Practical Garden- er,” was published before the Elements of Agricultural Chemistry appeared. + Van Helmont, Boyle, Bonnet, Duhamel, Tillet, and Lord Kames, zealously , endeavoured to establish the theory of water being the only food of plants; and Braconnot quite recently, by experiments with distilled water. Margraf, Bergman, Kirwan, Hassenfratz, Saussure, San Martino, and Davy, have expo- sed the fallacies of this theory. Every pound of rain water contains one grain of earth, besides other impregnations. Plants raised from pure water will ‘ vegetate only a certain time, and never perfect their seeds. Bulbous roots, which are made to grow in water, if not planted in earth every other year, refuse at last to flower, and even to yegetate. 1 ik 40 ON THE FOOD OF PLANTS. the atmosphere, and the repeated demonstrations that | the presence of air, or of oxygen gas, neither the germination i) of sceds can commence, nor the offices of vegetation proceed, —have led many inventors of' new hypotheses on thes growth and food of plants, to attribute to the agency of Air greater effects than is consistent with the daily evidence that many other things are equally indispensable. _ So the productive power of mere Earth has been exagge- rated. Jethro Tull, the imgenious author of the system of horse-hoeing, and after him Duhamel, having observed the excellent effects produced in tillage by a minute dix vision of the soil, and by the pulverization of the broken clod by exposure to dew and air, were misled by carrying these principles too far. Supposing earth to be the only food of plants, they contended, that by finely dividing the soil, any number of crops might be raised in succession from the same land, so as to render periodical fallows unnecessary. Duhamel attempted to prove that vegetables of every kind could be raised without manure: but he lived long enough to alter this opin- ion; his subsequent trials led to the mature conclusion, that no single material constituted the food of plants. The general experience of farmers had long before convinced unprejudiced theorists of that as a fundamental principle; and also that ma-~ . nures were absolutely consumed in the growth of plants. The principles of Sir Humphry Davy are nearly, but not im- plicitly adopted in the following recapitulation and synthesis. Water, and air, and earth (as the chief depository of solid — organic materials,) all operate in the process of vegetation. — ’ No one principle affords the pabulum of plants; it is neither water, which may form the basis of their fluids, for it exists in all the products of vegetation; nor-air, of which they give out various forms on distillation, such as oxygen, and azote, and inflammable gas ; nor charcoal, which is found on analy- sis to be a principal constituent of plants; nor the particles of flint, and of gypsum, at other times of lime, found in the stems of most vegetables. In all cases, the ashes of plants contain some of the earths of the soil in which the plant grew; but the earthy particles never exceed ,1 in weight of the vegeta- ble burnt. The soil is the great laboratory in which the main part of the food for common plants, or that which conduces to their gross bulk, is lodged and prepared. In proportion as some kinds of vegetables are found not to exhaust a soil, they must be supposed to derive organic materials from the air, as well as from the rain or other water with which their vessels” may come in contact; further, some contributions to the sub- — stantial juices of all plants may float among the constituents of airs To all kinds of leaves and fruit, the atmosphere may pos- Nike ON THE FOOD OP PLANTS. vat _ $ibly be the medium of the suBTILE AND VOLATILE PARTI- “LES WHICH CONSTITUTE FLAVOUR AND AROMATIC ESSENCE.* The colour of plants, in regard to the constant repetition of habitual tints, may depend greatly on their free communication with light: but the colour of the foliage, flowers, and fruit, is also affected by accidents in the soil and climate. The princi- ples of vegetable matter which escape from putrefying plants, are either soluble in water or 2ériform: in the one state, they form the most useful part of manure ; in the other, they swim in the atmosphere; in both states, they are capable of being as- similated by the organs of contiguous vegetables: for plants take up the elements found in their composition, either by their roots from the soil, or by their leaves from the air. The substances found in plants on analysis. may be divided into—1. Those which constitute the hard matter or frame of the plant. 2. Those which are eminently, if not solely, the nutritive materials, whether in the form of dry solids, soft pulp, or juice. 3. Those which serve as condiments, and con- tribute to diversify the scent, flavour, colour, and medical properties. The first class includes the simple earths, the earthy bases of compound substances, metallic oxides, and the basis of woody and vegetable fibre, great part of which is carbon.- It has been already mentioned that the earthy matter never exceeds one fiftieth part in weight of the whole plant, and it is commonly much less ; lime and flint are found the most frequently ; mag- nesia more rarely; and clay most seldom of all. No other ‘metallic oxides occur than those of iron and manganesum.— Charcoal is a principal constituent in all plants. The second class comprehends several substances which are common to the animal as well as the vegetable kingdom, and therefore may be regarded as directly nutritive to animals; along with a great number not generally present in vegetables to any sensible degree, although abundant in particular plants : these are, farina, or the basis of starch; gluten, or paste ; gum, or mucilage; gelatine, or the matter of jelly; (these three are not always distinguishable ;) albumen, resembling the white of an egg; sugar; water; wax; resin; fixed oils; fungin,a prin- ciple detected in the cucumber, abundant in mushrooms; and extract an indefinable substance, changing with the plant ana- lysed. The third class consists of acids, alkalies, and soluble salts ; —of these the most usual is sulphuric acid, combined with sul- phate of potassa ; likewise common salt, and phosphate of lime. The following seem to belong to this class, though sometimes * That is, such as are proper to the plant; for a rank soil may deteriorate the flavour of edible produce by conveying through the roots some remaining juices of a foreign substance. F 4a CAUSTIC LIME AS A MANURE. in intimate combination with substances under the first or second :—tannin, or the matter tanning leather ; indigo, and the various colouring matters ; camphor; the bitter principle; the narcotic principle, or opiate ; volatile oils. yp ‘ In addition to all the elementary parts actually found, some — aroma, or fugitive essence, which would belong to the third class if it could be detained, may go off in a form thinner than air, too subtile to be weighed or measured. The accumulation in a plant of the first class of things in a due and healthy proportion, may depend principally upon the soil, as. a mixture of earth; of the second, upon the manure ; of the third, in a slight degree upon the local climate, but emi-_ nently upon the power natural to the plant for attracting pecu- har particles in the earth and air. After these introductory remarks on the chief agents in ve- getation, it will be more easy to explain the operation of the different earths, or species of decomposed stone, which are laid upon lands as manure. P 1. LIME As A SOLVENT. (QuicKLimE.)—Lime, when first burnt, has a caustic property, speedily decomposes vegetable and animal fibre, and is soluble in water. After burnt lime has been exposed to the atmosphere a determinate time, it be- comes mild, by taking up carbonic acid ; loses its solubility ; and becomes chalk, or carbonate of lime. When newly burnt lime-is exposed to the air, it soon falls into powder; in this case it is called Slaked Lime. The same effect is at once produced by pouring water upon it, when it heats violently, and the water disappears. Slaked lime was used by the ancient Romans for manuring the soil in which fruit-trees grew. Nevertheless caustic lime is pernicious to vegetation, as far as it comes in contact with a growing plant. Where acid vegetable mould—a radical bane in some marshes, moors, and peat-lands—requires correction, proceed as under I. 1. When quicklime, 2. e. lime either freshly burnt or slaked, is mixed with aay moist fibrous vegetable matter, there is a strong action between the two substances; and they form a kind of compost, of which a part is usually soluble in «ater. Thus lime renders matter, which was comparatively inert, nutritive ;' and as charcoal and oxygen abound in vegetable matters, the lime is at the same time converted into carbonate of lime.* — So burnt lime, in its FrRsT effect, decomposes animal matter, and seems to accelerate the progress of such matter to a capa- city of affording nutriment for vegetables: gradually; however, the lime is neutralized by carbonic acid, and converted into a substance analagous to chalk ; but in this case it more perfectly * Elements of Agricultural Chemistry, p. 216. MILD, LIME AS A MANURE. eh, Se mixes with the other ingredients of the soil, and is more per- __ vadingly diffused, more finely divided, than: mere chalk artifi- cially applied. Burnt lime is probably more. beneficial to land tontaining much woody fibre or animal fibrous matter, than any ‘calcareous substance in its natural state.* Thus. 1s quicklime efficacious in fertilizing peats, and in reducing under tillage soils abounding in hard roots. But when animal or vegetable re« mains are destitute of fibrous. matter, so as not to require a powerful solvent, or when their bulk is not in too large a pro- portion, or their tendency to putrescency excessive and noxious, the application of quicklime is an unnecessary reduction of their strength ; therefore to cover or mix them with any simple earth, or stone pulverized without burning, will be better.—See “2. Mitp Lime.” ‘Lime moistened with sea-water yields more alkali (soda) than when treated with common water ; and is said to have been used in some cases with more benefit as . manure.{ ’ It is most important to the Agriculturist to be apprised of the difference in the operation of common limestone, which is of a pure white colour, and another kind of limestone which has a brown or pale yellow tincture: for a disclosure of the cause of this difference, the public are indebted to Mr. Tennant. It had long been noticed, that a particular species of limestone found in the north of England, when applied in its burnt and slaked state to land, in considerable quantities, either occasioned abso- lute sterility, or considerably injured the crops for many years. Mr. Tennant, by a chemical analysis, discovered that this kind of limestone differed from the common, by containing magne- sian earth: and from several horticultural experiments, he as- certained that magnesia, applied in large quantities, in its cause tic state, is pernicious to vegetation. Under common circum- stances, the lime from the magnesian quarry is, however, used in small doses, upon fertile soils, with good effect; and it may be applied in greater quantities to soils containing a very large proportion of vegetable matter. See, further, “ 3. Macnr- s1A;” also some restraints on the use of quicklime, in the. fourth paragraph of the next article. 2. Mitp Lime, powdered unburnt limestone, marles, and | chalks, have no solvent action upon animal or vegetable re- mains: on the contrary, they prevent the too rapid composition ‘of substances already dissglved; and they have no tendency to form sdluble|| matters.§ Calcareous matter, in some propor+ * Elements of Agricultural Chemistry, p. 21. t Ibid. p. 232. + Ibid. p. 21. {i Ibid. p. 216. § That is to say, not ina direct manner: but where there is any mineral ov saline acid in the staple earth or ordinary manure, the radical evil in what js called sor land, a top dressing of lime, (seg abeve, E. 1.) will nenfratize the ad ‘MILD LIME AS A MANURE. tions, seems to be an essential ingredient in all fertile soils; ne- cessary perhaps to their proper texture, or as a constituent in the organs of plants.* | a Although lime, when rendered mild by the recovery of the carbonic acid which was expelled in burning the limestone, does not undergo any further change in itself by continued exposure. .to the air, yet when saturated with moisture descending in showers or otherwise conveyed to it, it has the property of at- tracting an additional quantity, or second dose, of carbonic acid ; this—not entering into its constitution, but hanging loose- ly about it by a transient association—the mild lime readily parts with to vegetables growing near; at the same time the bulk of the mild lime is a little lessened by the action of mois- ture dissolving part of its crust. Lime in every state has also the property of attracting volatile oils floating in the air, as well _-as fluid oils in contact with it. The efficacy of a dressing of mild lime is proportioned to the deficiency of calcareous matter in the natural soil. All soils which do not effervesce with acids, are improved by mild. lime, and sands more than clays. ‘The rubbish of mortar, on account of the quantity of sand which it contains along with the chalk, is peculiarly fitted to benefit clayey soils. Marle, though the basis of it is mild lime, is to be distinguished from a pure calcareous dressing, because it ugually contains the re- mains of some animal matter, with a little clay or peat. When a soil which requires an accession of calcareous mat- ter, at the same time contains much vegetable manure, which is already soluble by the ordinary agency of moisture and natural heat, without any ingredient that calls for quicklime,—the cal- careous dressing should consist of chalk, marle, or mild lime ; acid matter. Quicklime is more efficacious than mild lime for this purpose; but simple chalk, also marle, applied in large quantities, will correct the evil. ” These manures, by neutralizing the acids combined with the mould, qualify the vegetable and other soluble substances also present, to be converted by the influence of the atmosphere and of moisture into nutriment for plants—. Ail the experiments yet made render it probable, that the food of plants, as it is taken up from the soil, is imbibed. by the extremities of the roots only. Hence, as the extremities of the roots contain no visible opening, we may conclude that the food which they imbibe must be in a state of solation first- And, in fact, the carbonaceous matter, in all active manures, is in such a state of combination as to be soluble in water whenever a beneficial effect is obtained. All the salts which we can suppose to make part of the food of plants, are so- luble in water. - This is the case also with lime, whether it be pure or in the state of a salt: magnesia, and alumina may be rendered so by carbonic acid gas; and even minute flinty sand may be dissolved in water. We can see, therefore, in general, though we have no precise notions of the very combi- nations that are immediately imbibed by plants, that all the substances which form essential parts of their food may be dissolved in water. System of Che- mistry, by Thomas Thomson, M. D, F.R. S$. E. Vol. V. p. 376. 3d. edit. Edin, 1807. * Elements of Agricultural Chemistry, p. 21. Compare with “ Practical Gardener,” p. 601. , UNBURNT LIME AS A MANURE. - a oe and the application of quicklime should be avoided; as quick- lime is disposed to unite with the soluble matter of dead plants, destitute of woody fibre, before the latter can have benefited the soil, and thus forms a compound insoluble in water. Quick- lime also, while it purifies, diminishes. the strength of animal ‘manures; it should never be applied with these, unless they are too rich, or for the purpose of preventing noxious effluvia, as in the cases of reducing carrion, or qualifying night-soil, af- terwards mentioned: it is calculated to render soft animal ma- nures less nutritive, and to make oily matters insoluble.* Quicklime is also injurious when mixed with any common dung, and tends to render the extractive matter insoluble. Fur- ther, when it unities with oily matters, it produces a soap not easily dissolved, like the less tenaceous compound formed by mild lime. Limestones that contain flinty or clayey particles, are not so good as others for burning into lime ; but they possess no nox- ious quality. Bituminous limestones contain a fraction of coally matter, never amounting to one-twentieth. They make good lime: and the coally matter, so far from injuring land, may, under favour- able circumstances, be converted into food for plants. Nothing yet has been said in regard to UNBURNT LIMESTONE. In a district where limestone is plentiful, and fuel scarce, a far- mer, anxious to leave no local resource neglected, might natu- rally fall upon the idea that lime, in an uncalcined state, if re-- duced to powder, or ground into small calcareous gravel, would be beneficially applied as a manure where mild lime would be serviceable, without being aware that the same practice had been already partially tried. The first attempt to convert unburnt limestone into a manure, was made by Lord Kames: no account, however, is known to be extant, from which we can learn how far it succeeded ; and the trial must be supposed to have proved abortive, if made ‘upon moss or moorish lands, which, owing to the great quan- tity of imperfectly decomposed vegetable remains imbedded in them, cannot possibly be benefited by any substance possessing less activity in destruction than caustic lime. Many years afterwards a large machine was erected in the county of Perth, which was furnished by three pounding-instru- ments of iron from the Carron Foundry, worked by a stream of water, for breaking unburnt lime into small rubble. This machine was unfortunately carried away by a flood before the effects of such lime as a manure could be decisively appre- ciated; but as far as the intervening time allowed of expeti- * Elements of Agricultural Chemistry, p. 212 A uy * 46 “PME OF LAYING ON MANURE, | ments, the conclusions were favourable... Much of it had been expended oa a farm of Colonel. Alexander Robertson. 5 As the theory of the thing, those who are sanguine in recom- mending a farther trial of it, suppose that unburnt limestone must be more powerful in its effects than mild lime, which has goue through the double process of burning and conversion into’ chalk. Any given quantity of raw limestone, say they,—a bush- el, ior instance.—contains twice as much calcareous earth as— the same bulk of slaked lime. Further, it is commonly ima- gined by persons who have used both kinds, without making any accurate experiments, that the effects of the raw limestone are slow, but more lasting; of the calcined limestone, more ex- peditious, but not so permanent. But they seem to overlook the true grounds of comparison. Limestone, in burning, loses, it is true, considerably in weight by the carbonic acid gas which is expelled : Lime, in passing from a caustic to a mild state, recovers this gas from the atmosphere ; but it does not regain the qualities of hardness and cohesion; and differs from what ~ it originally was, as powdered chalk from marble, or nearly so, according to the texture of the.fossil burnt. Unburnt lime- stone, therefore, has neither the solvent ¢ activity of quicklime,— nor the absorbing power of chalk,—nor the minute division of mild lime mixed with earth, while an impalpable powder. time of laying on Lime.—Nothing has been said of the stages in husbandry at which the application of lime is most: beneficially made : because this is quite distinct from an inquiry into the principles on which the good or ill effect of lime on different soils can be accounted for. Indeed it depends on con- siderations which the gardener and agriculturist, each alone im his own province, is qualified to weigh, from an intimate know-' ledge of their Tespective lands, and by the professional expe- rience gained in raising the intended crops. Nevertheless, in the valuable collection of Papers which conveys the gathered wisdom of the school of Scottish agriculture, some information occurs on this subject, which it may be useful to disseminate, as marking the general lines of a successful practice. “In the best cultivated counties, lime is now most generally laid on finely pulverized land, while under a fallow, or imme- diately after being sown with turnips. In the latter case, the lime is uniformly mild ; in the former, quicklime, as pernicious to vegetation, may be bene ficial in destroying weeds. Sometimes mild lime is applied in the spring to land, and harrowed in with grass-seeds, instead of being covered with the plough; and under this management, a minute quantity has produced a striking and permanent improvement in some of the hill pastures of the south- eastern counties. Its effects are yet perspicuous, after the lapse of nearly half a century. In some places, lime is spread on grass uae i U ’ MAGNESIA.—PHOSPHATE OF LIME. © 4G Jand, a year or more before it is brought under the plough; by which the pasture in the first instance, and the cultivated crops subsequently, are found to be greatly benefited. But in what- ever manner this powerful stimulant is applied, the soil is never exhausted afterwards by a cuccession of grain-bearing crops, a justly exploded practice, which has reduced some naturally fer- tile tracts to a state of almost irremediable sterility.”* 3. MaAcwrsra in a caustic state (burnt magnesian stone) is pernicious to vegetation: mild magnesia is in no respect hurt-. ful, provided there is a deficiency of calcareous matter in the soil. Caustic magnesia, applied to lands charged highly with rich manure, in a proportion not exceeding one-fifth of the ani- mal or vegetable remains, is speedily rendered mild by the car- bonic acid with which it is supplied, as the manure decomposes : but it should never be thrown on land where a portion of quick- lime already occupies the surface; because, while the quicklime is becoming mild by its readier attraction for carbonic acid, the magnesia retains its caustic property, and acts as a poison to most plants. Caustic magnesia will destroy woody fibre the same as quicklime ; and in combination with strong 'peat, assists in forming a manure. If the peat,equal one-fourth of the weight of the soil, and the magnesia do not exceed ,)th, the ‘proportion may be considered as safe. Where lands have been injured by too large a quantity of magnesian lime, peat will be an efficient remedy. See also above, 1. Lime as a Solvent, Magnesian limestones are usually coloured brown, blue, or pale yellow: they are found in the counties of Somerset, Lei- cester, Derby, Salop, Durham, Northumberland, and York; they are abundant in many parts of Ireland. 4. PuHospHare or Limr.—This is a compound of phosphoric acid and lime, one proportion of each; it is insoluble in pure water, but soluble in water containing any acid matter.-. It forms the greatest part of calcined bones. It exists in most excrementitious substances ; and is found both in the straw and grain of wheat, barley, oats, and rye; and likewise in beans, peas, and tares. In some places in these islands, it exists in a native state, but in very small quantities; it is generally con- _ veyed to the land by the medium of other manure ; and.is pro- bably necessary to corn crops, and other white crops.t In soft peats, or other lands which contain an excess of vegetable mat- ter, phosphate of lime is one of the most serviceable manures. See 1X. 6.3 5. Gypsum, SELENITE, or SULPHATE oF Limg, is found na- tive at Shotover Hill, Oxfordshire ; and abounds in many other parts of England. Natural gypsum commonly consists of wa- * General Report of the Agriculture of Scotland, &c. t Elements of Agricultural Chemistry, pp. 220, 221, + Ibid. p. 228. 48° GYPSUM AS A MANURE. ter, sulphuric acid and lime ; 22 parts of water, 46 of sulphuric uy acid, and 32 of lime. When the water is expelled by heat, the © other constituents keep their proportion unaltered. As a ma- nure, it is the subject of much difference of opinion. It may unravel some perplexities, and conduce to a fair estimate, it we treat of it under the four following heads : 1. Theory of its Operation.—Gypsum meets in few soils any thing which can decompose it; and while its elements remain fixed, it neither assists the putrefaction of animal remains, nor the decomposition of manure. ‘The ashes of particular sorts of peat contain a considerable quantity of gypsum ; some kinds, -a third part: and such ashes have been applied with good ef- fect as a top dressing for cultivated grasses. In correspondence with this, the ashes of sainfoin, clover, and rye-grass, afford considerable proportions of gypsum: but only a very minute quantity of it is found in barley, wheat and the turnip. The reason why the artificial mixture of gypsum with soils is not ge- nerally effiicaceous, is probably, because most cultivated soils contain sufficient quantities of it for the use of the grasses, and an excess of it above what other crops absorb in their growth, Gypsum is contained in stable dung, and in the dung of all cat- tle fed on grass ; and it is not taken up in corn crops, or crops of pulse, and in very small quantities in turnip crops. It is possible that lands which have ceased to bear good crops of cultivated grass, may be restored by a dressing of gypsum.* As to a general standard for the application of gypsum, those plants seem most benefited by its application which always af- ford it on analysis: such as lucerne, clover, and most of the artificial grasses : But where the soil already contains a sufficient quantity of this substance for the use of the grasses, its appli- | cation even on pasture cannot be advantageous: for plants re- -— ¥ quire only a determinate quantity of manure; an excess may ~ be detrimental, and cannot be useful.+ It has lately been asserted, on the authority of a gentleman resi- dent at Pittsburgh, in Pennsylvania, that gypsum is only useful as a manure in those parts of the United States that are distant from the sea not less than eighty miles. On the hypothesis that sea-air destroys the fertilizing principle in gypsum, Mr. R. Bakewell, a correspondent of the Monthly Magazine,t pro- ceeds to account for its failure as a manure in so many parts of England. It is enough to dispel this opinion to name the county of Kent, as the place where it has most fully succeeded. Sir H. Davy in directing our attention to the constituents of this manure, the composition of the soil, and the nature of the plant, has contributed material aids for judging when to apply “ Elements of Agricultural Chemisty, p. 224. + Ibid, 19, + For ‘October, 1815. GYPSUM AS A MANURE. 49 _ But perhaps he has not adverted sufficiently to the inimita-_ _ ble chemistry of Nature, by which she may disengage the ele-_ _ ments of gypsum when buried in a suitable soil, and enable par- ticular plants to extract them in a simpler form.’ It therefore _ becomes important to recollect, that the su/phuric acid, which + lodges in gypsum in a solid state, can be resolved into—su/phur- ous acid gas, about 40 parts; and oxygen, 60 parts ; and that when the water suspended with the two gases is dissipated, the proportions will be nearly, Condensible into sulphur - - ~ = - 16 parts, Sete he eT Brdter = 0 aye See Ly 8G . 100 Now, instead of confining the possible benefit to such plants as , afford gypsum in an unaltered state, may we not conclude that a large number of vegetables, constituted to reject the calcareous base altogether, may appropriate some modification of the other elements? ‘The saline. compounds (as professor Davy in another place notices) contained in plants, or afforded by their ashes, are very numerous. ‘The sulphuric acid, combined with potassa, or su/phate of potassa, is one of the most usual. Com- pounds of the nitric, muriatic, su/phuric, and phosphoric acids, _ _ exist in the sap of most plants.” In analogy with some late ex- periments of De Saussure, we may further suppose that sulphuric acid, diluted with water by the chemistry of Nature, may be instrumental in converting the starch of plants into sugar. “ As starch boiled in water with sulphuric acid, and thereby changed into sugar, increases in weight without uniting with any sul- _ phuric acid or gas, or without forming any gas, we are under the necessity of ascribing the change solely to the fixation of water. ‘Hence we must conclude, that starch-sugar is nothing else than a combination of starch with water in a solid state. The sul- phuric acid is neither: decomposed, nor united to the starch as a constituent ; nevertheless it is likewise found that long boiling in pure water does not convert the starch into sugar.”* This fact opens a large field for rational speculation gn the physiology _ of vegetables ; as it renders it possible that some of the mineral acids in the sap of plants, after acting chemicallyon the juices concocted into pulp, may be thrown out unchanged : they may al- ter the flavour without entering into the essence of the fruit. — Another step in the process of conversion brings us to pure sulphur. Some plants yield this on analysis. Seeds, sown by way of experiment on nothing but this mineral, have produced *See a Translation of the original Paper in Annals of Philosophy for De- ‘cember 1815. (No. XXXVI. pp. 425, 426.) G i ; . , t “+ VARA x A x . ee APE a0 ‘GYPSUM AS A MANURE. healthy plants ; and many soils, which nature has iepregpated with sulphur, are highly tertile, emis) The peats or loams on which gypsum has been most Success- ful, may contain vegetable acids calculated to decompose ita dt is true that the means by which human art can at present sepa- rate its elements are very limited. It is decomposed, 1. by the oxalic acid ; 2. by carbonates of potash; 3. by carbonate of stron- tian; 4. by muriates of barytes. The second and third solvents are only mentioned to be dismissed, as unlikely to be of sny use in agriculture: the carbonate of lime generated, by the second, being less soluble in water than the su/phate ; and chalk, when _ wanted, can be had at a cheaper rate. The third, carbonate of strontian, is a newly-discovered earth, of rare occurrence. As to the compound produced by the fourth, sulphate of barytes is perfectly insoluble in water: and it is a reasonable suspicion that . it would be pernicious to vegetable life. To recur to oxalic acid, the first-mentioned solvent. This is naturally present in wood-sorrel, and is procured artificially by the action of nitric acid upon sugar, and several other vege- table substances. Peat-moss, in an unreclaimed state, usually abounds with oxalic acid: hence there 1s a mutual action be- tween that sort of peatand gypsum. Perhaps such a compound might be cheaply imitated, by mixing vegetable mould and wood- ashes, urine and gypsum; or short muck, old cow-dung, sea- weed, and gvpsum,—substituting, where sea-weed cannot be obte 2ined, soap-lye ; or bleacher’s lees; or salter’s refuse, vege- tadle ashes, and water. It may be worth while’ also to try, whether in those cases where quicklime would form an insoluble compound, or dimin- ish the nutritive richness of a compost, gypsum may not be a capital ingredient; for instance, with some of the following sub- stances < oily matters ;—animal acids ;—all animal manures, par- ficularly such os contain albwfen, (one element in the white of egys is sulphur 3)—the common dung of cattle. Furthur,:as mild lime and gypsum seem to be as unlike each other as te vo substances with the same base can well be, it may be of practical benefit to compare their effects in various com- posts of the same strength. To close this theoretical part, sulphuric acid has a great at- traction for water, and may be useful in a soil in summer. Where the sulphur cannot be decomposed, it may diminish the cold- -ness of sorke lands. Gypsum may be offensive to delicate aphides by the same impregnation; and it may kill some hardy insects by setting into a hard crust upon them. In addition to the common case of land being already satura- ted with gypsum or lime, are there any descriptions of soil on which decomposed gypsum-might have a bad effect? 1. Would — it not deteriorate a soil containing particles of iron? This may GYPSUM AS A MANURE. 54 be put as a caution; for sulphate of iron is pernicious to vege- tation; but as lime is the antidote to that vice in a soil, decom | posed gypsum seems, even in this case, to contain its own re- medy, unless the proportion of lime be thought too low. 2. Might not the sulphuric acid hurt the texture of a soil almost wholly composéd of pure clay? Sulphate of alumina is not . baneful to plants as a salt, though, as a mineral earthy compound, it is not the most tractable under tillage : but here again lime is Bae to prevent its formation, or to dissolve it. . 1. Experience of it abroad. —Tt is about half a century since wana was discovered to have IN PENNSYLVANIA almost a | magical influence on the growth of red clover; and it is there. held in rising estimation. ‘Che Pennsylvanian farmers seem to have derived from Europe the first suggestions for applying this manure to artificial grasses. M. Gilbert, from whom a quota- tion is given in Sect. 1v., states the practice to have long pre- vailed in France with signal success. In Germany, Mr. Mayer, a clergyman, discovered the use of gypsum as a manure about the year 1768; and in Voghtland, in Saxony, gypsum-earth is said to have converted several barren tracts into fruitful frelds. The agriculture of Switzerland has also reaped much benefit from the same resource. 111. Experience of it in this Island.—Perhaps it has not yet received a fair trial here; but as far as experiments in different counties of England and Scotland are reported, the mass of evi- dence is against it. [As the Finst Experiment of Arthur Young relates to a particular point in the “‘ Method of Preparing and Applying it,” it is given under that head.] SECOND EXPERIMENT dy the EDITOR of ANN. AGRIC. * Marked five square Rods of Clover on a good Turnip Loam with a gv ee bot- tom, worth 10s. an acre, in March, 1791. “No. 1, Sprinkled with one quart of gypsum. . Two quarts, Three. _ Four. . Five quarts of wood ashes. “Nos. L and 2 were equal, and rather superiour to any of the rest. No. 5. was the worst. The clover manured (compared with the adjoining land that had no manure) was not only considerably higher, but thicker, of a deeper and more luxuriant colour, and of a broader leaf. * One quart to a rod, is five bushels to an acre. I am confident that neither such a quantity of night-soil, pig-dung, peat-ashes, nor any other manure with which I am acquainted would have had an equal effect. The result of this ex- periment is therefore quite contrary to that of last year.* ALY spe { EXPERIMENT dy JOHN ALLEN, Esg. on four square Rods, First Year's ' clean Clover. Nos. 1 and 4. No manure. . No. 2. Four quarts of sifted cinder-ash which had never been exposed to the atmosphere. _ No.3. One quart of gypsum. * Annals of Agriculture, Vol. XVI. p. 184. la Ae 'S2 +). GYPSUM AS A MANURE. — ~ we When the clover was in full head, alPbeing mown, the produce of Nos. Le and 4. averaged 38 lds. 6 oz. each. . \ . pes No. 2. weighed 50 dbs, A i ee No. 3. 54 $ lbs.* ati. ! Another gentleman, Mr. R. Procter Anderdon, of Henlade, — Somerset, after detailing some trials, says, —‘* Hence I conclude, #s far as my:experiments go, that on many plants, or on many _ soils, gypsum powder will have no effect ; but that it has an ef- fect on.old clover, on a loamy soil; and that a greater effect may - be reasonably expected from it, when applied to younger plants of the same sort.”’+ _ From a subsequent Letter of the same Correspondent, it ‘seems greatly to promote the growth of Chicory, and to be de- structive to the slug. A farmer, near Epping, in 1791, found it greatly to increase the returns from a sowing of oats. The extensive experiments made by a Kentish farmer, in the years 1792, 1793, and 1794, are reported in the Bath Papers, _ vol. VIII. The first states generally that they were chiefly up- on “ light loams and poor calcareous soils, especially of the chalky kind.” It is therefore very important that the following observation, which occurs in detailing a particular experiment, should have a conspicuous and prominent place. “ A light ~ loamy earth to the depth of three feet on chalk, produced much better crops, than a shallow surface on chalk, both having been _ manured with gypsum.” The plants were chiefly sainfoin, cow- grass, and Dutch clover ; and repeated trials were attended with favourable results. , To these might be opposed many instances of the failure of ‘gypsum as a manure, in various parts of England, even when applied to grass-lands: but the failures uniformly consist, not in any pernicious effect, but in the want of any superioug, re- turns, compared with unmanured lands of the same quality. Whether it is that in North Britain the farmers find it more profitable to pare off peat, and use it 2s a compost for lands un- der tillage, than to attempt the reclaiming of entire beds of | soft peat by immediate cultivation,—or whether they have cheaper top-dressings,—the sum of their experience in regard to gypsum, is expressed in the following sweeping conclusion : ** Gypsum has not hitherto been attended with any success in ‘Scotland.”{ As to grass-lands not abounding in-vegetable re- mains, what has been stated under head 1. makes it less surpri- _ sing that a dry powder, so hard to decompose, should not have produced any effect corresponding to its reputation in Ame- rica. * Annals of Agriculture, vol. XVI. 303. } Ibid. vol. XVI. p. 297. ie + General Report of the Agricultural State on Scotland, vol. IL. p. 53%. ¢ GYPSUM AS A MANURE. wh tv. Method of preparing and applying it—Even those wri- ters who maintain that there is nothing like gypsum, pointedly differ in their instructions for preparing and applying it. One in the opposite hemisphere says: “*‘ The spring of the year has been esteemed the best season for sowing it; but Ihave sown it in March, April, May, June, July, August; and I know no difference in its effect. You will observe, it is only a top ma- nure, therefore must be sown on a sward of grass: it is parti~ cularly good for white and red clover. It may be broken by hand, and afterwards sifted; but we stamp it, and afterwards pass it through our mill-stones: 1T MUST NOT BE CALCINED”* . +++... Six bushels to the acre I use, and it is preferable to fifty loads of the best dung. This you must think extrava- gant; it is so, and yet true.”’} M. Gilbert, author of a Treatise on Artificial Grasses, pub- lished in France,t says, that “it produces the same effect wHE- THER IT IS CALCINED OR ROUGH, if it is but powdered; that six bushels, Paris‘measure, manure very well an acre for a year; and that half that quantity does for the two following years. The only thing to be attended to, is, not to sprinkle this manure before the seeds which are mixed in the herbage are near ripe : if sowed sooner, it makes the trefoil grow so fast as to smother the grass with which it is mixed........ It only produces_ beneficial effects when sowed after or before rain ; sowed on dry land which continues such, its effects are nothing.” As to cALcininG: It is not likely to make any difference, be- cause the sulphuric acid in gypsum cannot be expelled by the most violent heat of the furnace ; and an experiment of Arthur Young§ countenances the assertion, that the effects of gypsum are the same, whether calcined or rough. It is thus stated ; ** Spots were staked out on an upland meadow of clover. No.1. A perch uncalcined. The grass weighed, green, 112 dds, No. 2. Calcined. 114 lds. No. 5. No manure. 113 lbs.” The produce is uncommonly great; but the equal success of the unmanured piece makes this experiment a comparative failure, The American farmers employ it upon new ground, and strew it upon the surface. In reclaiming a peat not already dis- posed to form sulphate of lime, it may qualify an excess of sofi vegetable matter very beneficially. It does not follow, however, that on lands differently circumstanced, particularly upland * Extract of a Letter from Philadelphia, dated Sept. 16, 1785, Annals of Agriculture, vol. XV. p. 109, { Ibid! June 1, 1790, p. 110. + Reviewed in Annals of Agriculture, vol. XV. p. 444, § Annals 9f Agriculture, vol. XIV. p, 319. - Ention hie to cc adhered to ; and if a restorative is Rieti gypsum, the history both of its successes and its failures, would in: recommend a compost containing peat, or some imitation of it,” Bes: This will be a fair test of what it can effect. ty 6. Burnr Cray.—Of late, very flattering reports have been a circulated of the practice of burnimg clay into ashes, for a top ‘dressing. It is not arecent invention: for very particular in- iy structions for doing it are given in a small Treatise, published : near a century ago.* Revived lately in Scotland, the process, described in a letter by Mr. Craig, has excited much attention, and induced many spirited agriculturists, in various parts of the island, to adopt it ona large scale. The expectations from it are sanguine ; although the experience had of it is not yet ex- tensive enough to form a ground of recommending it for gene- fi ral application. It is called “* Burning Clay for Manure : yet, as the torrefied powder is not valued for any vegetable ashes suppo- sed to be contained in it, as in the common practice of paring and burning, but is simply to operate as burnt earth, it were more correct to modify the term to “‘ Burning Clay toimprove the Tex- ture of the Soil.” This is not a verbal distinction, but a practical difference. If attention to it should much contract ‘the field for the operation, it may prevent many disappointments. Thus, suppose the agriculturist is induced, from his system of farming, to cul- tivate turnips on a’ clayey soil, not well adapted to their growth, it is plain that the ashes of burnt clay, copiously distributed over the surface, would immediately consult the habits of the plant, by dividing a tenacious, and rendering drier a humid soil; and thus, without supposing the burat clay to act as a manure, the texture of the staple would receive a permanent improvement. On the other hand, if ona soil not rich inthe common basis of ve- getables, and which is to be planted with any of the exhausting culmiferous crops, or other crops dependent on a generous soil, the panacea of mere burnt earth is resorted to, asa substitute for the long tried proportions of consumable manure, the result of such an ill-timed application of fire must be disappointment. : Indeed the operation of burning clay for ashes is so tedious and expensive, that even where the circimstances of the land demand such an improvement, the outlay would overwhelm the farmer—unless he intermit the practice during those stages of rotation in which he can raise beans, and other crops fit for clay * The Practical Farmer ; or, the Hertfordshire Husbandman. See a Letter in the Farmer's Magazine, No. LXUI. with the signature “ J.G. F.’ It is also men- tioned in The Country Gentleman’s Companion, by Stephen Switzer, Gardener. (London, 8vo. 1732.) This latter work states, that the Earl of Halifax was the inventor of this resource: and it gives several letters, written in 1730 Sy Nie and 1731, attesting its success in several parts of England; with accounts from a Scotland ‘that it had answered better than lime or dung !—but was found toe expensive. - ON CLAY-BURNING.| soils, by, easier modes of tillage. If, however, he is satisfied to prepare land, by this practice, for the green crop, or other stage of a rotation which most requires it, and is attentive at other times to keep up the vegetable strength of the staple by soluble manures adapted to repair the exhaustion of preceding harvests, and to meet the appetite of the expected crop, the texture of the soil will be gradually improved, while the dan- ger of relying upon burnt earth as a manure will be avoided. If the surtace burnt is a peat, or moss, or contains the roots or other remains of plants, the ashes may be truly a manure; but then the principle and its application are assimilated to the practice of paring and burning turf, and the useful commerce in peat ashes ; neither of which is a novelty. So a marl, fraught with animal remains, is decidedly a manure. The clay may be either burnt in heaps, or in kilns. For this purpose, it is dug or pared off in shallow spits, about four in- ches thick. Two layers of these are commonly taken. Whe- ther any part of the subsoil should or should not be also dug up, depends upon its composition. See above, Sect. 1V. It accelerates the process of ignition to set the spitfuls first to dry, either separately or in open piles. The kiln may be fired with furze, wood, cinders, coal, or any combustible refuse. As to the quantity of ashes to be applied, the Hertfordshire Husband- man says,—‘* About forty bushels, sown on an acre by the hand, out of the seed-cot, and harrowed in with barley and grass seeds, does vast service.” The Scottish agriculturists assign from twenty to twenty-five cubic yards per acre, as a dressing for turnips. ; When kilns are used, limestone may be burnt with the clay. Hf this practice be combined with that of burning with lime better composition obtained. It may be acceptable to describe a good method of doing both together.* Pare off the sods, or turf, and surface clay, with the skim- coulter plough, or other convenient instrument, and dry the "i parings ready for burning. Get quicklime fresh from the kiln in the following proportion: having marked out a base for the "pile, for every square superficial yard, three Winchester bush- els of lime ; or for a mound seven yards in length, three yards and a half in breadth, 72 bushels. In building, begin with a layer of dry parings, six inches in height ; on which spread half the lime intended to be used, about five inches thick, mixing sods with it; then a covering of eight inches of sods ; on this the other of the mound at this stage being about ayard. Mr. Curwen deems it better to suffer it to ignite of itself, than to effect the combustion _* The foilowing is derived from the Letter of Mr. Curwen, of Workington- _ Hall, to Mr. Dempster, of Dunichen, published, by permission, in the Farmer’s Magazine, No, LXIV. p. 411. half of the lime is spread, and covered a foot thick ; the height’ instead of fire, the expense will be lessened, and a manure of © . x \ Dunes ‘ a 56 MINERAL SUBSTANCES. _ ; SaaS by applying water. In twenty-four hours it will take fire. When the fire is fairly kindled, fresh sods must be applied. Mr. C. — recommends obtaining a sufficient quantity of ashes, before any clay is put upon the mounds. The fire naturally rises to the top. It takes less time in piling, and effects more work, to draw down the ashes from the top, and not carry the mound higher ~ than six feet. ‘The clay if not sufficiently burnt is lumpy, and untractable under tillage: on the other hand, Mr. C. regards” | calcined ashes as of no value; but they ought certainly tobe burnt to a powdery state, or until they will fall to powder from a slight stroke ; and it does not appear that the calcination of any earth lessens its absorbing power. The finer:clay-ashes are, the great- er is their capacity of absorption from the atmosphere. Some idea may be formed of the spirit with which Mr, C. has taken up the trial of this system of surface-soil and clay- burning, when he says, “I have just completed paring twenty-~ six acres of clover lea of the second crop, which I intended next year for turnips. The sods were well broken with the harrows, which freed them of the greatest part of the mould. ‘The residue was burnt, and has afforded me above a thousand single-horse carts of ashes. There are twelve mounds with se- venty-two Winchester bushels of lime each........1 have ma- nufactured for use this season, two thousand single carts of ashes.” On lands thus manured, while turnips and clover have, in the’ most favourable cases, surpassed expectation, wheat has fallen below it. At present thie balance of experience from the recent trials seems to have this inclination: the advantage of burning clay alone is questionable, as‘a measure of general applica- tion; and unless vegetable matter or lime is burnt with it, the benefit will seldom repay the expense. When clay has been burnt alone, dung, or other manure containing vegetable nutri- ment, should be spread with it, especially in preparing land for an exhausting crop. Many discoveries in tillage fall into disrepute by being ap- plied without regard to local circumstances, or by being con- tinued after a sufficient change has been effected in the original constitution of the soil. Burnt clay can only be what physicians ‘ would call a topical remedy. VIL. By introducing. Mineral or Saline Elements as Ma- nures.—Mineral substances are more or less contained in decayed animal or vegetable matters. When these sub- stances have been extracted in a pure state, by a chemical pro- cess, they are in general too expensive and too useful in the arts’ or” in the ordinary affairs of life, to be applied as manures: on which account the following experiments will serve rather to shew the principle or cause of a fertilizing, or contrary effect, from the gross matters in which they are found, than for the purpose of expending the pure extract on any soil, as in the ex- * ASHE LF si DIFFERENT SALTS COMPARED. _ matter, containing a particular chemical substance, may be bene- ficial,—while that substance in a pure state is pernicious. Alkali of Soda is the basis of Marine Salt. “ When common _ salt acts as a manure, it is probably by entering into the com- position of the plant in the same manner as gypsum, phosphate of lime, and the alkalies. It has been proved to have been sometimes useful in small quantities. It is likewise offensive to . insects. Some persons have argued against the employment of it, because, when used in /arge quantities, it either does no good, or renders the land sterile ; but this is not a cause for en- tirely rejecting it. In Cornwall, the refuse salt from the large works of dry-salters—which, it is to be remembered, contains some of the oil and scales or other parts of the juices and skins of fish—has long been known as an admirable manure. But | as latent muriate of soda is one of the constituents in almost every kind of animal and vegetable manure, the cultivated lands _ of these islands may be supposed to contain, in general, a sufli- cient quantity for the purposes of vegetation, (not to mention _ that the surrounding sea must have an effect on the air and soil ' toa considerable distance inland ;) so that a direct supply of it _ to the soil may be found, in most cases, not only useless but in- __—jurious.* In the water given to plants which are natives of the sea-coast, a minute infusion of common salt would consult the natural circumstances of that description of vegetables : indeed they languish without it.+ 2. ComPARATIVE Errect or DIFFERENT SALTs.—Profes- sor Davy confirms and illustrates the above and affords a general principle for the solution of contradictory results under altered circumstances, by an experiment on the effect of different salts conveyed in water to the roots of plants. The subjects of trial were separate spots in a garden, on which grass and corn were growing. The soil of the place was 24 of finely divided earth or chemical elements of earth, and. 16 of vegetable matter; and of the whole, less than one part in _ 100 was saline matter, principally common salt. The saline __ substances tried were super-carbonate of potassa, (crystals of __ soda,) sulphate of potassa, (vitriolated tartar,) acetate of potassa, (foliated earth of tartar,) nitrate of potassa, (prismatic nitre,) and muriate of potassa; sulphate of soda, (g\lauber’s salt or vi- triol of soda;) sulphate, nitrate, muriate and carbonate of am- monia. The quantities applied were two ounces to each spot * Elements of Agricultural Chemistry, p. 230. *) t System of Chemistry, by Thomas Thomson, M.D. F.R.S.E, vol. V. p. 364, Sdedit. Edinburgh. 14 periments ; on the other hand, it will appear, from some of the _ details under this article, why‘an earthy mass, or heap of refuse _ Wh. 1. Common Sar, or Muriare or Sopa.—The Mineral a light sand,—of which 100 parts contained 60 of flinty sand, | twice acweek. In all cases where the quantity ecw art of the water, the effect was injurious ; but least so in the instances of the carbonate, sulphate, i muriate of ammonia. — When the quantities of the salts were y45 of the solution, the | effects were different :— Ihen, the plants watered with the solu- tions of the sulphates grew just in the same manner as similar plants watered with rain water : ‘Those acted upon by solutions of nitre ; acetate; and super-carbonate of potassa; and muriate of — ammonia ; grew rather better ; those treated with the solution of carbonate of ammonia grew most luxuriantly of all: The plants watered with the solution of nitrate of ammonia did not grow better than those watered with rain water; “ probably (says Sir H. Davy,) the free acid had a prejudicial effect, and interfered With the result.” But if the effect was equal to that of rain water, there was no proof of a pernicious agency ; the ill effect was nierely negative, and seems rather to have prescribed a slight increase in the quantity dissolved in the water. IX. By Manuring with Refuse Substances not excremen- titious.—Heaps of refuse matter, which contain excrementitious substances incidentally, and but in a small proportion, will be included under this article. 1. Srreser AND Roav Dirt and the SweepinGs or Houses ynay be all regarded as composite manures. As they are de- rived from different substances, their constitution varies; but in all cases thev refresh and strengthen a soil. Scrapings of roads not clayey are beneficial without exception: those from high-roads are enriched in far the greater degree by the drop- pings of cattle. “Phe promiscuous dung which is gradually in- corporated with the sludge, 1 is so perfectly reduced by exposure to the weather, that it takes the appearance of earth. The effects of road-drift are in many cases beneficial in a higher degree than the cultivator might expect from its known composition : but the greatness of the benefit may be well accounted for, by considering that the gravel, or slate, or stone, which is ground into earth by the passing of carriages along a road, is necessa- rily virgin-earth, having never been in a state to support vege- aa Fine road-stuff is better than dung on pasture land, 2. Soor is a very powerful manure ; its great basis is char- coal, in a state of solubility by the action ‘of air and water. — It contains also salt of ammonia, with a portion of oil. To mix soot with quicklime is a bad practice; because much volatile alkali is thus disengaged, without any benefit to the land. This manure requires no preparation ; and is well fitted to be used in a dry state, as a top-dressing (a peck to four square poles of land) thrown in with the seed. It is a good improver of cow- dung and goose-dung; either of which alone, and in a fresh state, are of little power. Further, its alkali tends to make oily particles miscible with water. 8. CoaL-Asues.—It appears from an experiment of Mr. tes) ti GOAL-WATER.—BONES.—HAIR, &C. r Be right, afterwards particularly adverted to, that coal-4shes on e a dung ; while it is inferior to the dung of sheep, and something better than that of horses, f | 4. Coat-Water, or the liquor produced by}the distillation of coal, is said to be a good manure. 5. Woop-AsHEs consist principally of the vegetable alkali united to carbonic acid: and as this alkali is found in almost all plants, it may be an essential constituent in the organs of the greater part. The vegetable alkali has a strong attraction for water. See the comparative efficacy of wood-ashes with that of coal-ashes and the dungs of several kinds of cattle and do- - mestic fowls, under X. 6. 6, Carsonate or Ammonta.—The liquor produced in the distillation of coal at the Gas Establishments, may be recom- mended as a valuable manure on the following accounts. First, it principally contains carbonate of ammonia; (sce the experi- ments by professor Davy already sketched :) secondly, it con- tains also a little sulphur. In the proportion of one gallon to 16 or 18 of water, this liquor may be applied to all green crops as a manure, with good effect. When the object is to destroy insects, three gallons only of water should be added to one of the liquor. 7. Coa Tar.—The tar produced in making carburetted hy- drogen gas is beneficial as a manure, conveyed in proportion- ate heaps of earth or marle. One gallon of this tar being mix- ed with about a wheelbarrow full of mould or fit earthy materi- als, will form a compost of great activity. This may be cither ploughed in or used as a top-dressing, as the nature of the land. and crop may render expedient. 8. Bones consist of phosphate of lime and decomposable ani- mal matter. Bone powder, bone shavings, and bone ashes, are _ serviceable where phosphate of lime is to be supplied to a soil. Bone ashes ground to powder will impart a reduced share of benefit to arable lands, containing much vegetable matter, and may perhaps enable soft peats to produce wheat ; but powdered bone, in an uncalcined state, is always to,be preferred to bone. ashes, because the oil and ather animal matter with which bones are richly charged has not been dispelled. _ 9. -Horwn is still a more powerful manure than bone, as it con- tains a larger quantity of decomposable animal matter :* it is _ very durable in its effects on a soil. 10. Hair, Fearuers, and Wootten Rass, are all analo- gous in composition ; they are more nearly allied to horn than to bone; they contain a great quantity of albumen (a substance similar to white of egg,) gelatine (basis of jelly,) with some oil, Woollen rags act powerfully for one year. “ Flements of Agricultural Chemistry, p. 198. aplot where barley is to be grown has the same efficacy as hog- — 60 ‘BLEACHER’S WASTE, &c. 11. Keruse or Skin anp Learuer, accumulating in differ- ent manufactories—such as furricrs’ clippings, the shavings ; f the currier, and the offals of the tan-yard, and the 'glue-maker—form | highly useful manures ; any one of which, buried in the soil, operates for a considerable time.* 12. Breacuer’s Wastre.—It is usual to cast away the resi- duum of the stills as a worthless article: but surely if some competent person were employed to separate the sulphate of soda from the sulphate of manganese, the former might be turned to a good account. The waste solutions of the-oxy-muriatic salts are also convertible into a valuable manure. See the experi- ments of Professor Davy, above. Humboldt, about 1810, dis- covered that a weak solution of such preparations, has the pro- perty of accelerating and enlarging the growth of vegetables. Gardeners whose grounds are in the neighbourhood of bleach- fields, would do well in availing themselves of all the advanta- ges their situation affords them for making experiments on this interesting and important subject.t The waste lees, after boil- ing linen yarn or cloth, may also be used for alkalizing com- posts. 13. Soarer’s Waste has been recommended as a manure, under, the supposition that its efficacy depended upon the differ- ent saline substances which it contains : but the quantity of these is very minute indeed; its chief ingredients are mild lime and quicklime, either of which, when a supply of calcareous materi- als, or when a caustic solvent is wanted in a soil, may be had at a cheaper rate. 14. The Fiurp, or Dissotvep Parts, of ANIMAL SuB- STANCES, require some preparatory process to fit them for ma- nure. The great object is to blend them with the soil in a pro- per state of minute division, When these have been applied in a rank or unreduced state, bad effects have followed. Perhaps while they retain the combinations of animal matter unchanged, or not entirely broken, they are ill adapted to promote the func- tions of vegetable life. Thus tallows and oils, received ina crude state by the roots, may clog the pores of the bloated plant, repel dews and aqueous fluids, and obstruct the free communication of the leaves with the atmosphere. One mode is, to spread the animal fluid thinly on the land un- der tillage, and previous to putting in the seed or plants, to sut- fer the free escape of the volatile particles that will go off by ex- halation. The better mode is to convey animal matter in a com- post of earthy or vegetable materials. Boop is a good manuree The Scum taken from the boilers of SUGAR-BAKERs consist principally of budlocks’ blood. When sugar-baker’s waste has been reduced to the finest state * Elements of Agricultural Chemistry, p 199. ' + Chemical Essays, by Samuel Parkes, F, I. S. London, 1815. vol. IV. py 160, } @IL AND BLUBBER. i Gt times its bulk of some earthy substancé, which may be enriched with a proportion of vegetable mould or desiccated dung. _ Graves also are too rank both for corn and grass, unless con- veyed in a compost of earthy materials ; wood ashes may be profitably added, as having a tendency to divide and correct the particles of tallow. 4 OILY sUBSTANCEs contain a deal of carbon, and are employ- ed as manures with great advantage. Animal or vegetable al- kali increases their fertilizing power, by converting them into soaps. Quicklime diminishes their, efficacy, tending to make them insoluble.—Tratn-o1L and BLusser. All the practical writers on the application of train-oil and blubber, and similar refuse, agree that to rectify it, it must be made into a compost with a great body of earth, though they may recommend differ- ent proportions under the diversified circumstances on which in- dividual experience is founded. The ingenious Dr. Hunter* advises a compost thus formed : Let 12/bs. of American potash be dissolved in four gallons of water: mix the solution with twenty bushels of dry mould, and fourteen gallons of train-oil. A Correspondent of the Farmer’s Magazine} found that blub- ber in a crude state, as he applied it in a first essay, destroyed, instead of assisting, vegetation. ‘Twelve years’ experience has led him to a most successful method of using it, which he pre- sents to the notice of other agriculturists. His plan is to make it into a compost in the proportion of nine loads of earth to one load of blubber. He first makes a layer of earth two feet thick, —building it a foot higher at the sides, three feet inward, like a solid wall, to form a cavity for the blubber. When the blubber has been laid on a foot in depth, similar layers are repeated toa convenient height till the blubber is expended, leaving three feet of earth for the top layer: The entire heap is then beat down close at the top and sides to exclude the air. In this state it will ferment, and the earth becomes impregnated with the foul air of the blubber. When this fermentation abates, which it will do in about two months, the heap is to be turned over from top to bottom. The bottom layer of earth, which thus becomes the cover, will require some addition in thickness, to prevent the escape of air by the second fermentation : When this abates, the compost is again turned over; and after a third fermenta- tion, becomes fit for use. The communicator of this method then adds: “ The mixing or applying lime therewith, I have found detrimental, as the lime reduces the blubber, and prevents fermentation. I never use this compost until it is nine or twelve. * Georgical Essays. + No. LXII. (dated Aug. 7, 1815,) p. 287. possible, it will still be improper for application as a manure, until it has been mixed and incorporated with three or four 620 months old. In this state, 1 have applicd—to both pralind tillage land—about {0 or 15 loads of the compost per acre, cach load weighing two tons; and have cut from the grass land three tons of hay per acre, and after-grass in proportion. I have also used it to tillage crops of wheat, beans, and potatoes, on a field of 20 acres, that has not been fallowed for ten years, until this present summer, but manured annually in the above proportion; and from which I have reaped five quarters of wheat per acre,—five quarters of beans,—and from 1300 to 1500 pecks of potatoes,—with those crops in succession. ‘The land is a strong clay ; and the only difficulty from constant cropping is.in keeping it clear from short twitch grass, of which if left in the Jand, the blubber encourages the growth.” Pulverized O1L-c axe has been used with advantage as a ma- nure: it is an antidote to the wire-worm, especially if mixed with elder or wormwood, when it proves a certain means of de- stroying the worm 3 an effect which is explained by reflecting that oil is destructive to most insects. A mill has been invent- ed for pulverizing oil-cake as a manure, which, with one horse, will,crush five tons per day. 15. Reruse Fisx forms an excellent manure, provided the he uantity be limited,—and, that sufficient time intervene, before e plants are put in, for the combinations of animal matter to be destroyed. In an instance, recorded by Mr. Young, of too great a quantity of herrings having been ploughed in for wheat, so rank a crop was produced, that it was entirely laid before har- vest. In order to prevent a dressing of fish from raising too luxuriant a crop, they should be mixed «ith earth, or sand, and sea-weed. Their effects are perceptible for several years. ‘¢ The manure produced in the fishing villages from the mix- ture of all oily and fishy substances, favours bear [barley] and green crops; but when used much, renders the soil unfit for pro- ducing oats: hence that soil is called poisoned.””* 16. Carrion is not commonly used as a manure, though there are many cases in which such an application might easily be made. Horses, dogs, sheep, deer, and other quadrupeds, that have died accidentally or by disease, are too often suffered to lie exposed to the air, or immersed in water, till they are de- voured by birds or beasts of prey, or entirely decomposed: meanwhile, noxious gases are given off to the atmosphere, and the land where they lie is not benefited. By covering a dead animal with six times its bulk of soil, mixed with one part of lime, and suffering it to remain for a few months, the decompo-_ sing carcase is made to impregnate the superincumbent mould with soluble matters, so as to render the compound an excellent manure ; and by mixing a little quicklime with it at the time of. * Sinclair’s Statistical Acccount of Scotland, vol. Vl. p. 201. MALT DUST.—SEA WEED. 63 ‘its removal, the disagreeable effluvia would be in a great mea- _ sure destroyed. Any waste carcase may also be dissolved by _ enclosing it in a heap of vegetable matter in a state of fermenta- tion: but it is advisable to urge and sustain the fermentation at ' a heat high enough to kill gentles and caterpillars. 17. Rape-Srep Caxr, composed of the husks or bran of rape-seed, is a restorative manure for arable land. It should be used when fresh, and turned in with the seed. There is also a rape-cake formed of the ashes from burnt rape- _ straw, which contain a deal of alkali. ‘This is a good dressing for turnips. ; 18. Maxr Dust is a manure of great power and vivacity. _ It answers best as a spring top-dressing. Provide for wheat ten _ quarters per acre; barley, cight; grass-land, four. It excels in ' stimulating a cold soil. 19 19. Sra weEep.—In some of the maritime counties’a great _ deal of sea weed comes in on the shore. ‘This manure is trans _ sient in its effects, and does not last for more than a single crop. - But for one crop it has been found to be the most productive of _ any.* Itis sometimes suffered to ferment before it is used: but - this seems wholly unnecessary ; for there is no fibrous matter ren- dered soluble in the process, while a part of the manure is lost. The best farmers use it as fresh as it can be procured. Where _ it cannot be immediately applied, a good resource to save the _ juices draining from it is to lay it on a flattened heap of earth preparing for compost.—Sea-weed, as a manure, improves the _ growth and taste of esculent herbs. 20. Dry Srraw and Srortep Hay, with every sort of haulm, is convertible into manure for all lands. In general, such sub- __ stances are made to ferment before they are employed; “ though _ it may be doubted (says Sir H. Davy) whether the practice _ should be indiscriminately adopted. There can be no doubt that the straw of different crops immediately ploughed into the ground _ affords nourishment to plants : but there is an objection to this method, from the difficulty of burying long straw, and from its rendering the husbandry foul. When straw is made to ferment, it becomes a more manageable manure: but there is likewise a great loss of putritive matter. More manure is perhaps sup- _ plied for a single crop: but the land is less improved than it _ would be, supposing the whole of the vegetable matter could be bee" finely divided and mixed with the soil. It is usual to carry straw _ that can be employed for no other purpose to the dunghill to fer- ment and decompose: but it is worth experiment, whether it may not be more economically applied when chopped small by a proper _ machine, aad kept dry till it is ploughed in for the use of a crop. _ An this case, though it would decompose much more siowly, and * Sinclair’s Statistical Account of Scotland, vol. YI. p. 202... 4 Elements of Agricultural Chemistry, p. 194, 64 VEGETABLE MoULD.—woopy FIBRE, eer i produce less effect at first, yet its influence would be much more i) lasting.”’* On this question, and the proposed artifice for preserving the whole quantity of refuse straw or hay as manure for the soil, the Reader’s aitention is invited to the Strictures and Sugges- tions annexed to the article, ManaGement or Manure FROM THe Homrsteap. 21. VeGerTaBLeE Movu.p, or tree-leaves decomposed, is a Manure so nearly fit for universal application, that no other ex- ception need be made to it than the case of a soil being already too rich. It is too valuable to be used on commen occasions, alone. It may be mixed with sand, perfectly rotted dung, ex- hausted bark, or other ingredients, according to the wants of a epi . Woopy Fisre.— Mere woody fibre (says Professor Aa seems to be the only vegetable ates that requires fer- mentation, to render it nutritive to plants. “ Tanners’ SPENT BARK is a substance of this kind. Mr. Young, in his Essay on Manures, which gained him the Bed- fordian Medal of the Bath Agricultural ‘Society, states that, “spent bark seems rather to inure than to assist vegetation ;” which he attributes to the astringent matter that it contains, But, in fact, (remarks the Professor) it is freed from all soluble substances by the operation of water in the tan-pit. If injurious to vegetation, the effect is owing either to its agency upon wa- ter; or more probably, to its mechanical structure and effect, being very absorbent and retentive to moisture, and yet not pene- trable by the roots of plants. at By ‘Tanners spent Bark,’ in the above passage, it is to be understood only the bark from which the tanning principles has been extracted in a tanner’s vat. This substance, when fer- mented, as directed under “ Hot-house,” in Abercrombie’ s “Practical Gardener,” is a great auxiliary to vegetation: in general, the excitement from it is only safely given through the medium of mould ; but the offsets and cuttings of many plants, struck into the surface of a bark- bed, will vegetate without earth, See “ Pinery,”’ and Grape-house.” With regard to its applica- tion in the open garden, it is not a fit dressing forcommon beds, till reduced to an earthy state. Inert Peaty Marre is similar, in respect to the absolute necessity of fermenting it before it can be beneficial as a manure. It remains for years exposed to :vater and air without under- going change ; and, in this state, yields little or no nourishment to plants. Lord Meadowbank has recsmmended a mixture of farm-yard dung for the purpose of bringing peats into fermenta- ath Elements of Agricultural Chemistry, p. 194. Ibid ‘ “SHAVINGS OF WOOD.—~PEAT ASHES. 65 _ tion; for this end, dung is well adapted, but any putrescible substance will serve equally well; and the more readily any re- fuse litter heats, the better will it answer the.purpose. In or- dinary cases, one part of dung is sufficient to decompose three, and from that to six, parts of peat: green vegetables, mixed with the peat, will accelerate the fermentation. In the height of summer it will take about three months—and in the season f comprehending winter, six months—to reduce fermented peat to the state of vegetable mould. ‘Ten cubic yards per acre may ___ be ploughed in for wheat. ? SHavincs or Woop, anv Saw-pust, will require as much _ dung, or green vegetable refuse, to bring them into fermentation, _ as the worst kinds of peat. . The risre and Grain oF woop can be much sooner decom- _ posed by the action of caustic lime, than by the process of fer- mentation, The young shoots of pruned trees, and similar ve- _ getable refuse, may be speedily converted into a manure, by be- ing laid ina pit, with alternate layers of quick-lime. Mr. Brown, _ of Derby, has been honoured with a medal, from the Society of the Adelphi, for this contrivance, extending the application of a principle which has been immemorially known, and recently much adverted to. See above, Lime As A soLVENT. 23. ASHES OF VEGETABLES NOT wooby.—The conversion ; into ashes by combustion of vegetable refuse matter, otherwise _ easily reducible into manure by fermentation, may sometimes increase its fertilizing power in one of thtse ways: either by _ augmenting the tendency in the manure to produce carbonic acid, under the combined action of charcoal, moisture, and air, —or by the effect of the alkali in relation to some other manure, or the texture of the soil,—or by some ingredient which would _ be pernicious in combination being expelled in the burning. _ Vegetable ashes, applied as a top-dressing, may also contribute _ ‘to the destruction of insects and their larve. . _ __ Burnt Srraw is said, by an intelligent practical farmer,* to _ be amanure that will insure a crop of turnips. The compara- _ tive efficacy of burnt straw is shewn by an experiment of Mr. _ Wright, recorded in a subsequent page. _ Pear Asuzs have a local utility as a top-dressing for culti- _ vated grasses. The peat ashes of Berkshire and Wiltshire, in particular, are sold at a considerable price for manuring artifi- cial grass-lands, and are much celebrated for their good effect. _ Professor Davy, having analysed as well these ashes as the soils _ to which they are successfully applyed, found in the soils _ themselves no sensible quantity of gypsum} the ashes, on the _ other hand, consisted in great part of gypsum, with a little iron, ___a little common salt, and variable quantities of calcareous, alu- ‘f * A General View of the Agriculture of the East Riding of Yorkshire, by H. F. Btrickland, Esq. t Elements of Agricultural Chemistry, p. 19. J 66 NIGHT-SOLL. | eye 1 ARNO Uy) e) (POY ia minous, and siliceous earth, and sulphate of potassa. Bui sl chi is not generally the case with peat ashes: to produce this pre- ponderating quantity of gypsum, the peat must be charged with y vitriolic matter, and lie on a substratum of calcareous earth.— Turf-ashes are used in the Netherlands for manuring clover and _ other grass lands; and force great crops.” X. By Excrementitious Substances applied as Manure.—The potency of dung as a manure varies with the animal affording it. 1. DunG or SEa-Birps.— One of the most powerful dungs is that of such sea-birds as feed on animal food, The naturally sterile plains of Peru are fertilized by guano, a species of dung collected from small islands in the South Sea, frequented by sea-birds. It is used over a great extent of South America, applied in very small quantities, and chiefly for crops of maize. The dung of sea-birds had not been used in this country as a manure until a trial of it was made in Wales, at the recom- mendation of Sir H. Davy; in which instance it produced a powerful but transient effect on grasses. ‘That sagacious and candid experimentalist hence conjectures, that the rains in our climate materially injure that species of manure, unless where it happens to be deposited in caverns or fissures of rock, out of reach of the weather. 2. Nricut-So1t, in whatever state used, whether recent or fermented, is a very powerful manure, and capable of supplying abundant food to plants, Saw-dust is a good vehicle for it. The disagreeable smell of night-soil may be destroyed by mix- ing it with quick-lime; and if exposed to the atmosphere in, thin layers, strewed over with quick lime, in fine weather, it speedily dries, and is easily pulverized : so prepared, it may be used in the same manner as rape-seed. ‘The Chinese mix their night-soil with one third of its weight of a fat marle, make it into cakes, and dry it by exposure to the sun. These cakes, which are said to have.no disagreeable smell, form an article of commerce. In-the neighbourhood of London, this manure is prepared for sale in a concentrated state, so as to be inoffen- sive in the carriage, even when conveyed in bulk. The Come _ pressed Night-soil may be commodiously used as a top-dressing for wheat in the spring of the year, and for all kinds of spring corn, for young clovers, and other green crops ; one hogshead will be sufficient for an acre, when it has been prepared with due attention to the preservation of its fertilizing properties, As an enriching manure, many experiments have established, that human ordure is to be ranked many degrees before the lung of the pigeon, hen, sheep, or swine ; powerful as all these are. But its effects are not so permanent as those of many other substances. From recent experiments, Mr. Middleton con- cludes, that no other manure can compete with it for the first year after its application ; in the second year, the benefits from iy it are very much diminished ; in the third, its effects, nearly, if Re f i We Ak , RN 0 i OS way Nal ti \ Ng Ph Went uf en : * a | DUNG OF FOWLS, 67 not quite, disappear. Much depends on the depth of soil. _. There can be no doubt that a substance in which the principle of vegetable nutriment is highly concentered, is in proportion well calculated for speedily restoring or enriching land, and for forcing great crops without detriment,—supposing the staple to _ be deep enough for tillage, and to be fitly constituted as to tex- ture. On the other hand, a shallow dip of mould requires con- tributions of new earth, without which forcing manures will eS Wa _ but exhaust it sooner. » - On the authority of trials which seem to be convincing, - some writers have insisted that an inconceivable Joss of valua- a ble fluid is incurred by exsiccating night-soil, Though this la i aa 2 aa oe with earth, where it can be consumed on the spot ; yet it 1s none _ against the use of the article in a cgncentrated state, in which _ the loss, as far as the escaping fluids are not transferred to some absorbent compost, falls upon the preparer; .while the expense me lessened. 3. Picron’s Dunc is next in fertilizing power. When dry, it may be employed as other manures capable of being pulverized, One tenth part of pigeon’s dung, four parts of sand, and five parts of vegetable mould, is a good compost for a cold heavy soil. The following interesting quotation must recommend pigeon’s dung as a fine ingredient in a compost for melons. “ The pro- _ duce of the sub-district of Linjan (in the province of Ipak) is not inferior to that ‘of the most fertile spots in Persia. ‘Whis _ sub-district is about seventy miles in length and forty in breadth : it is irrigated by canals cut out from the Zeinderood, and covered with villages, which are surreunded with gardens and prodigi- ous numbers of pigeon-houses. On inquiry I found that these birds are kept principally for the sake of their dung, and that the acknowledged superiority in the flavour of the melons at Ispahan, is alone to be ascribed to this rich manure. The lar- gest of the pigeon-towers will sell for three thousand’ pounds ; and many of them yield to the proprietors an annual income of two or three hundred pounds each.”’* 4, The Dunc or Domestic Fow ts approaches very nearly _ in quality to pigeon’s-dung. It is very liable to ferment.t _ Sir Humphrey Davy here ranks the dung of domestic fowls ‘next to pigeon’s dung, without defining what species of fowls 4s intendeil, or discriminating between the different kinds of do- ments recorded in the Agricultural Magazine, that Hen dung, * Geographical Memoir of the Persian Empire, by John Macdonald Kennier. Political Assistant to Sir John Malcolm, in his Mission to the Court of Persia, 4to. London, 1813. p. 119. _ ¥Flements of Agricuittral Chemistry, p. 204. $ may be a good reason tor forming this substance into a compost _ of carriage, in regard to the solid essential part, is materially mestic fowls. It appears from a set of comparative experi- om Lh DN shy ( ar ane teey Yana gees ky ie OS ot CF ME ee a aa 68 EXPERIMENTS WITH MANURES, Ab . . , . ‘ By | hy at the dung of the common fowl, is most efficacious ; Duck dung is to,be rated second ; while Goose dung was found so in- ferior that the produce from a spot manured with it was not much above the average of three patches sown without manure. See the statement at length, under article 6. -. 5. Rassit’s Dunc has been used with great success as a manure ; so much so, that it has been found profitable to keep’ rabbits chiefly for the sake of the dung, and to have the hutches constructed in subservience to the object of accumulating it with- out waste. 6. The Dunc or Catrtir.— Of the dung of cattle (says Sir H. Davy,) that of hard-fed horses appears to be the strongest. The dung of sheep and deer is thought to be more efficacious than that of oxen. ‘The dung of oven is supposed, by many, to require a long preparation to fit it for manure. To combat the opinion that ox-dung requires a long prepara- tion, Sir Humphry then enters upon a course of argument against the general practice, in regard to fermenting promiscu- ous dung-heaps. ‘‘ If the dung of cattle is to be used as a ma- nure, like the other species of dung which have been mentioned, there seems no reason why it should be made to ferment except ‘in the soil; or if suffered to ferment, it should be only ina slight degree. The grass in the neighbourhood of spots where unfermented dung has been dropt, is always coarse and dark green: some persons have attributed this to a noxious quality in unfermented dung ; but it seems to be the result rather of an excess of food furnished to the plants.” The estimate founded on the experiments adverted to under article 4. above, does not correspond with the order in which the dung of horses and that of sheep are mentioned by Sir H. Davy; and it countenances the objection held in common by many. practical men against the use of fresh cow-dung. Nine different kinds of manure having been tried on patches of bar~ ley, the result was as follows :— Hen-dung sess Most efficacious. Duck-dung.....Second in power. Sheep-dung...... Third, Coal-ushes. 2 Hog-dung. § Horse-dung......Fifth. Wood-ashes......Sixth. ee eri $ Seventh. _Not much above the average of three patches sown without manure. Cow-dung.......Evidently prejudicial. Exactly alike. Fourth ' The quality of the land is not stated ; but possibly one cause of the cow-dung being prejudicial, was the natural coldness of the soil. Moreover, barley is extremely impatient of dung that is not well digested and divided. But on warm arid soils, cow- dung may be an improving manure, if fermented with other rin is ny |) Je OS Tents ave! St). > ” D x bal ; ‘ . Pr) ep oa Res ee Nand i Sa, wf wer eS EXPERIMENTS WITH MANURES, 69 dung, or kept alone till it can be pulverized. In canvassing this point with an eminent horticulturist, he informed me, that it is his own practice, and that of many gardeners skilled in pre- paring choice composts, to keep cow-dung for a period of three years, before they apply it either alone as a manure, or as an in-— . gredient in acomposite mould. When used ina fresh state,asa manure, it shoufd never be alone, but mixed with any such arti- cles as the following, of a warm nature, and easily pulverized : the dung either of the sheep, the hog, the horse, the rabbit, the pigeon, the hen, the duck, with‘some of the animal manures ; or with lime and sand, marle, soot, coal-ashes, the ashes of any burnt vegetable, or other substance ; as the soil may want either to be strengthened, or to be cooled with as much cow-dung as can be applied without its peculiar disadvantages. Properly , qualified, it is a good dressing for most shrubs and fruit-trees. fe As the texture of the soil varies, or as a plant of a different ___nature forms the crop, so the proportion of fertilizing power _ which a comparative trial of manures has fixed in one instance _ __-will vary in another. Still some manures seem to be universally inferior ; while others, though not always standing in the first _ place, may be relied on for conducing to a profitable return. H A paper by the Rev. James Willis, President of the Christ- Church Agricultural Society, records two valuable experiments, | made to ascertain the positive effect of different manures on the product of potatoes, in the same soil, with the same sort, and __under the same management. One experiment was on the eyes alone, or small cuttings ; and the other on the whole root; so , that the increase from these also may be compared. The sort i planted was the Wurrre Rounp, on a clean sandy loam, well pulverized, in rows two feet asunder, twelve inches distant in é the row, and six inches deep. i TABLE of EXPERIMENTS with the EYES only, planted on the 12th April 1819. H MANURE. PRODUCT. 3 .1. Pig’sdung - + - + ~ = -1 bag and half, per lug. ve 2. Mown grass = + - - ~ = 1 bag and 2 bushels. 3. Sheep’sdung - - = ~ - 1 bag and 1 peck, ’ 4. Coal-ashes - - - - = ~ 1 bag and 1 peck. 5. Hen’sdung - - - - = = 1 bag and 1 peck, a - 6. Oldrags - - - - + = + 1 bag 2 gallons, } 7. Garden rubbish - - - - ~ ‘1 bag 1 gallon. 8. Horse-dung - - - * = = 1 bag 1 gallon. 9. Turf-ashes » ~ - = = + 1 bag] gallon, 10. Turf-dust - - - - = ~~ 1 bag. 11. Rivermud -~ - - ~ «+ - 1 bag. 12. Cowdung- - - - « + = Lbag, 7] TABLE of EXPERIMENTS with the WHOLE ROOT, planted on the LOM, April 1811, MANURE, PRODUCT. I, Pig’sdung - - - - + - Lbag 3 pecks, per lum. ' TOK EXPERIMENTS WITH MANURES,. ~ MANURE. PRODUCT. Na Ti 2. Sheep’s dting - - + - - 1 bag and half. Bua $8. Coal-ashes = - - - - + 1 bag and half. ON 4. Oldrags - - - - - + = 1 bag and half. it 5. Mown grass - - + - = - 1bag, 2 bush, 2 pecks, 1 gall. 6. Hen’s dung - - - - - = 1 bag 2 bushels. . 7. Rivermud + - - - - + 1 bag 1 bushel. 8. Turf-ashes - - - - - + 1 bag, 3 peclgs, 1 gallon, 9. Horse-dung - - - - - = 1 bag 3 pecks. 10. Garden rubbish - - - - - 1 bag $3 gallons. 11. Turf-dust - - - - - - - ILbag 3 gallons. 12, Cow-dung - - - - - - 1 bag 3 gallons. On reviewing the two Tables, we may perceive, that though the relative powers of the manures may vary a little, from ac . cidental causes, yet the increase from the Whole Root, as wied against that from the Eyes with the same manure, is uniformly so much greater as to prove decisively that it is more profitable to set either a Half or Whole Root, than to plant Eyes, The author of the Experiments also informs us, that in digging up the potatoes, he found those produced from the eyes much smailer. x To the passage above quoted (p.68,) Sir H. Davy subjoins ; “ The question of the proper mode of the application of the dung of horses and cattle, however, properly belongs to the ar ticle of composite manures ; for it is usually mixed in the farm-_ yard with straw, offal, chaff, and various kinds of litter; and itself contains a large portion of fibrous vegetable matter.” See next section, Manacrment or Manure rrom THE Homre- STEAD. 7. Hoc-punc—according to the comparative statement above, (p. 68,) ranks immediately after sheep-dung, and before horse- dung. j 8. Urine.—All urine contains the essential elements of ve- getables in a state of solution: but the various species of urine _ from different animals differ in their constituents ; and the urine — of the same animal alters when any material change is made in its food. During the putrefaction of urine, the greatest part of the soluble vegetable matter contained in it is dissipated : it should consequently be used as fresh as possible; but if not mixed with solid compost, it should be diluted with water; as when undiluted, it contains too much animal matter to form a proper fluid nutriment for absorption by the roots of plants. Putrid urine abounds in ammoniacal salts ; and though less ac- tive than fresh urine, is a very powerful manure.* | MANAGEMENT OF MANURE FROM THE HOMESTEAD. _ Composite Manurr.—Under the head X. 6, it has been no- ticed, that the consideration of the right mode-of applying the * Elements of Agricultural Chemistry, p. 201. ‘a n| ny Wi t ) Ey y WR HOMESTEAD MANURE. 4 Dung of Cattle, on a large scale, belongs to the article Compo- site Manure; because it is mixed in the farm-yard with straw- litter, and with various kinds of vegetable offal, which itself contains a large proportion of hard fibrous matter. The remarks scattered in the Elements of Agricultural Che- mistry on this subject are thrown together in the following ab- stract. Professor Davy’s Theory on Composite Manure. A slight incipient fermentation is undoubtedly of use in the dunghill ; for by means of it a disposition is brought on in the woody fibre to decay and dissolve, when it is carried to the land, or ploughed into the soil,—and woody fibre is always in great excess m the refuse of the farm. ‘Too great a degree of fermentation is, however, very prejudicial to the composite ma- nure in the dung-hill: it is better that there should be no fer- mentation at all before the manure is used, than that it should be carried too tar. This must be obvious, from the following considerations. ‘The Professor’s arguments may be arranged . under five heads : four theoretical ; and one practical. 1, “ An immeasurable quantity of substance:disposed for con- version into food tor plants is then suffered to escape in the form of drainings and vapour. During the violent fermentation which is necessary for reducing farm-yard manure to the state in which it is called short-muck, not only a large quantity of fluid, but likewise of gaseous matter, is lost; so much so, that the dung is reduced one-half, and from that to two-thirds or more in weight : now the principal elastic matter disengaged is carbonic acid ith some ammonia; and both these, if attracted by the moisture in a soil, and retained in combination with ity are capable of becoming nutriment to plants.”—In aid of this _ reasoning, the Professor relates an experiment, from which he considers that he has obtained particular proof that the gaseous matter from fermenting dung is of great utility to growing plants. He introduced the beak of a retort filled with ferment- ing manure, consisting principally of the litter and dung of cat- tle, into the*border of a garden among the roots of some grass. In less than a week, a very distinct effect was produced upon the spot exposed to the influence of the matter diséngaged in fermentation; the grass grew with much more luxuriance than in any other part of the garden. ir. “‘ There is (continues. the author of the experiment) an- other disadvantage in the loss of heat; which, if excited in the soil, is useful in promoting the germination of the seed, and in assisting the plant in the first stage of its growth, when it is most feeble and liable to disease ; and the fermentation of ma- nure in the soil must be particularly favourable to the wheat tii - -MANAGEMENT oF crop, in preserving a genial temperature beneath the surface, late in the autumn, and during winter.” eR 111. ** Again, it is a general principle in chemistry, that in all cases of decomposition, substances combine much more readily at the moment of their disengagement than after they have been perfectly formed. And in fermentation beneath the soil, the fluid matter is applied instantly, even whilst it is warm, to the organs of the plant; and consequently is more likely to be efficient than in manure that has gone through the process of fermentation, and of which all the principles have entered into new combinations.” hr tv. The Professor, in another place, reminds us, that the ultimate results from an excess of fermentation in a heap of ~ manure are like those of combustion. v. “A great mass of facts may be found in favour of the application of farm-yard dung in a recent state. Within the last seven years, Mr. Coke has entirely given up the system of applying fermented dung; and he informs me (says Sir H. Davy) that his crops have been since as good as ever they were, and that his manure goes nearly twice as far.” vie Objection noticed by the Professor.—Sir Humphry then candidly states an objection made by. many practical Agricul- turists to his system for managing composite manure. “ A great objection against dung but slightly fermented, is, that weeds spring up more luxuriantly where it is applied.” To which he answers : “ If seeds are carried out in the dung, they certainly will germinate ; but it is se/dom that this can be the case to any extent: and if the land is not cleared of weeds, any kind of manure, fermented or unfermented, will occasion their rapid growth.” | vit. His own Practical Application of the above Theory.—It is to be observed, that the Professor admits the beneficial ten- dency of a slight. or incipient fermentation in mixed heaps. ‘To regulate the practice of fermenting composite manures, as the basis of the heap may vary, these are his two general principles: 1. Whenever manures, consist principally of matter soLUBLE IN WATER, their fermentation or putrefaction should be prevented as much as possible. 2. The only cases in which putrefaction ean be useful, are when the manure consists chiefly of animal or vegetable riBRE. Agreeably to the above principles, Sir H. Davy then gives Directions for the Management of Farm-yard Dung in the Heap, and for its Application to the Soil: of which the following is the substance. ’ ** Where farm-yard dung cannot be immediately applied, the destructive fermentation of it should be prevented as much as possible. For this end, the dung should be kept dry, and unex- posed to the air; for moisture and contact with the oxygene of HOMESTEAD MANURBE. 13 the atmosphere tends to excite fermentation. ‘To protect a heap from rain, a covering of compact marle, or of a tenacious clay, should be spread over the surface and sides of it.* * Watering dunghills is sometimes recommended for check- ing fermentation: but this practice, although it may cool the dung for a short time, is inconsistent with just views ; for moisture is a principal agent in all processes of decomposition: dry fibrous matter will never ferment. “Ifa thermometer plunged into the dung does not rise to above 100° of Fahrenheit, there is little danger of much aériform mat- ter flying off. If the temperature is higher, the dung should be immediately spread abroad. When dung is to be preserved for any time, the site of the dunghill is of great importance. In order to have it defended from the sun it should be laid either under a shed, or on the north side of a wall. ‘To make a complete dung repository, the floor should be paved with flat stones, a little inclination being made from each side towards the centre: in the centre there should be drains, connected with a small well, furnished with a _ pump, by which any fluid matter may be collected for the use of . the land. It too often happens that the drainings of the dung- hill are entirely wasted.” The Professor then adverts to the application of littery dung on pastures. “ If slightly fermented farm-yard dung is used as a top dressing for pastures, the long straws and untermented ve- getable matter remaining on the surface should, as soon as the grass begins to rise vigorously, be removed and carried back to the dunghill: in this case no manure will be lost, and the hus- bandry will be at once clean and economical.” Free Remarks on the Theory, and on its Practical Applica- tion.—Having finished the above compendium of Sir H. Davy’s Views onthe Management of Manure from the Homestead, the Writer subjoins a few Strictures and Suggestions in regard to the five principal grounds on which the Professor recommends that composite manure should be, under common circumstances, - but slightly fermented before it is spent on land. The first objection of the Author of the Elements to the re- duction of farm-yard dung to the state of short-muck, relates to the loss of riu1p, and of GAaszous matter. Every person must admit that the subtraction of a fluid sub- stance from a mass of dung must diminish the strength and rich- ness of the intended manure; and though in some cases the bulk of the fluid may be rain water or waste water accidentally fall- ing upon the dunghill, yet it cannot be denied that part of the essence of the dung must be carried away in the drainings. Ne- vertheless, where the drainings of the dunghill can be saved in * Flements of Agricultural Chemistry, p. 209. f K ‘ ah 2 aio MANAGEMENT OF be ey TS iy ae hy OO EL ae See Ai a AP Oe 2 } wey Wy a proper receptacle, in order to be applied to heaps of dry com- . post, or to land under tillage, there is no loss to the Agricultus rist in the separation of the fluid part of the manure. " Sir Humpry Davy’s plan of a well to catch the drainings of a dunghill is sufficiently practical ; and where the nature of the te- nure makes it worth the cultivator’s while to have such a well, is perhaps as good a method as can be devised for obviating the loss of fluid matter. In other cases, where a reservoir cannot be formed for the drainings from an accumulating mass of dung, it will be a ser- viceable expedient to prepare a thick layer of good earth (cul- tivated mould or rich loam,) raised at the edges as the basis of the intended dunghill: which layer of earth, by continually recei- ving the moisture draining from the superincumbent dung,will be as valuable for manure, when the whole is removed as the dung — itself. The escape of GasEous matter forms another part of the ob- jection to fermenting dung, above cited from Sir H. Davy, Un- der a previous head, Improvement or Sorts, V. By Fallow- ing, the writer, in endeavouring to meet a speculative objection to fallowing, founded on the escape of gaseous matter, has offer- ed some considerations why that should not be estimated as a loss. (p. 28. 31.) As to the escape of gaseous matter from fermenting dung, it is not easy to prevent it, if the dung lie any where but in the very bosom of the land. Perhaps, however, when dung must be partly decomposed before it is applied, a case of mould over the heap would attract, and bold in combination, much of the carbonic acid and ammonia which would else escape in vapour. Such mould, like that laid underneath, would be imbued with sustenance for plants, but in a less degree, and only in propor- tion to the completeness of the fermentation. But the covering of earth, would in some instances be liable to be burnt, and in others be apt to prevent the free fermentation necessary to dis- solve woody fibre. As to the experiment of the vapour directed from the beak of a retort on some grass growing in a border, as recorded by _ the Professor; it may be in place to observe, that the effect on grass, of which the species is not mentioned, fails to afford a sufficient criterion’:—had the subject of experiment been a kit- chen esculent requiring a rich soil and yet impatient of rank ma- nure, and had the trial been protracted till the time of flowering or fruiting, some satisfactory conclusion might have been form- ed with regard to the influence of the gas on the growth of the plant and the flavour of its edible produce. The second objection to the fermentation of a heap of dung intended for manure, at a temperature exceeding 100 degrees of Fahrenheit as a maximum, adverts to the loss of neat, The WY avn) 7 PS) i é MOMESTEAD MANURE. , GS _ way in which the loss of heat is supposed by the Professor to - operate, involves so much that is hypothetical, that an appeal to the result of trials in which the different causes that may ope- rate are not distinctly measured will not be decisive in favour of the théory ; because it frequently happens that an effect which pretty constantly attends a particular practice is attributed to the wrong cause. Now it appears contrary to nature, and to the principle on which a warm climate is imitated in any forcing de~ partment, to excite the roots of a plant with any degree of arti- ficial heat, unless there be some cover or weather-screen to de- tain the warm vapour and create an atmosphere corresponding to the soil ; and the seed or root ought to be protected trom the fermenting substance by a coat of earth. The disadvantage from the loss of heat in manure may there fore be more correctly attributed to the. entire exhaustion of the fermenting principle, and to the want of its influence in commu- nicating a kindred fermentation to dry fibrous matter already in the clod, and so reducing it to a state of aliment for plants. On the other hand, it may conduce to the health and vigour of the plants to have the fermentation in the soil completed before the new crop is put in, so that the growing roots may not be in con~ tact with putrefying substances. The third ground of argument for postponing the decompo- sition of manure till it be imbedded in the soil is drawn from a principle in chemistry, that suBSTANCES ESCAPING FROM DE- COMPOSED BODIES ENTER INTO NEW COMBINATIONS MOST REA- DILY WHEN FIRST DISENGAGED. ‘There seems no reason for contesting the practical inference deducible from this principle —provided the intention be confined to promoting the combina- tion of the matter disengaged from the dissolving body intimate- ly with the soil: either by casing the dunghill with mould to be used as compost, or by burying the manure in a clod when par- tially fermented, and before it is much exhausted of the rudi- ments of vegetable matter by drainings or vapour; taking care to have the manured soil afterwards properly turned and expo- sed to the air before it is sown or planted, so that whatever pase- ous matter has a natural tendency to fly off into the air may free- ly escape. But the theory on which a beneficial influence is an- ticipated from applying the “ fluid matter while it is waRmM to the organs of the plant,” seems to be repugnant to the process of nature, and closely allied to that hypothetical branch of the se- eond ground of argument already objected to. Nor is there any proof that a fermenting substance is fit food for a living plant : the residuum of animal and vegetable substances purified by free exposure after decomposition seems, in the circle of natural ope- rations, to contribute chiefly to the bulk of new plants: but when erude animal or vegetable remains, or the fluid or solid sub- ‘stances rejected in the composition of animals, are administer- SSN MANAGENEN!D OF ed to growing plants, the rank manure appears, from numerous experiments, to make them flourish unnaturally at first, and then to induce disease and premature decay. To give an instance from each class, this is the known effect of oil, tree-leaves, urine, night-soil, The utmost extent of the fourth objection will bring the dung which has casually fire-fanged ona par with the ashes of various burnt vegetables. How far the condensed power of these (a specific sort being chosen for the desired effect) has been found on particular soils cropped with suitable plants, to exceed that of the very same sort of manure in an unfermented state, or in any stage of decomposition short of combustion, is well known to practical cultivators, and has been partly noticed in p. 65. This objection is again adverted to under Recapztulation, sect. 5. Fire-fanging, regarded as a mischief, as an excess beyond the farmer’s design is easily prevented. The fifth argument is entirely practical, and the authority ad- duced in its support one of the highest. If, under different lo- cal circumstances, other cultivators are led to the same conclu- sion by similar experiments carried on for a sufficient course of time, this single argument will have more weight than the other three ; because there can be no competition between theory and experience. : It is nevertheless to be observed, that the statement made above, after Mr. Coke, is not clear in its import: it can have the weight just conceded to it only on the construction, either that some of the manure made on the farm that was expended under the old system is disposable for some other purpose under the new,—or that some expense in fetching manure from distant places, that had used to be incurred, is saved: but if the state- ment, “‘ that the crops are as good as ever they were, and that the manure goes nearly twice as far,” mean only that the dung when now expended is nearly twice as much in bulk or weight, and covers the surface of the field more thickly in the same pro- portion, the benefit is merely illusory,—the crop is confessedly not increased ; while the carriage of the dung to the land must be heavier, and the labour of spreading it greater. The following Experiment of Mr. Wright, recorded in the Agricultural Magazine, N.S, No. 3. is a valuable contribution on this subject. V7 a < i) be WM >| ra © = ¢ ‘jooaed yous De sjeysng $2% *spoysng ZS “sjaysng gs *s[aysnq OF *sjaysnq gc ‘yng ‘dog “way ee ee 1 ‘UWIN]OD puodas at} UT se parnurU Play ay} Joy suydans [Jeus e YEA “Apeay j -oadsai doas qove ur SunjeS jo ssuadxa ay} 0} yenba ynoqe sea Wt Gurmoyy Jaye puv aojaq pea7 } 0} SV Z "poor-zey "P23 8 “729 OT 4239 [ZB "322 OF = IVa 03°89) FZS *4920)9 ‘doIg "Ps 2490 wag "49D sag 2190 ag alID wad 9 ‘yord yore uo uMos syood % ‘hang ‘doig ‘pe syood ¢ sjoysnq Pt ysed { sjeysng og syood ¢ sjoysnq 9¢ syood g sjaysng 0S : 2 $21 8 “BT “OOT Let E “162.9 sq] L°#8 T “289 OF 89) 9 "38 G “9029 ST - - sdruiny, ‘dot “3st ee ee 4 "JQ CT "SuOT, Z "suo LS ‘QUNUBI 271047244 ‘punoryy oY} uO Jung plo sywuoyy ys fazvJs AVIS punorg ug Avedj}g Aapteg A1q Sung 2qv1g us}oy e ut Sunp aquis ysorg ‘21a £ sanyunng Surmoyjoy ayy jo uorewoyddy o]suis v woy “¥OndOUd Put “SdOUD AAISSAOIAS ‘yoRs 0} PazOle Sutoq punossy Jo pooy & FLA SaunUDyy LAOHLIM 20g pazvayjng D wo pus ‘TUVONVIA fo SAN 3auHL UO TNAWINAdXA AALLVAVdWNOO 78, MANAGEMENT OF To complete this experiment, there wants a notice of propor- tion of weight which a heap of rotten dung would lose imeight months : three tons of strawey dung would scarcely make more than a ton and a half of completely rotted dung: but when dung is reduced one-third in weight, the fermentation may be consi-’ dered far enough advanced tor agricultural purposes in general. Supposing the original quantity to have been on a par, the above experiment would be, in every instance but the first, in favour of the:rotted dung: the small inferiorjty in the case of the turnips may be attributed to there being an excess of manure above what the plant required; so that had but one ton been put — on for the turnips, and the other ton been reserved for the se- cond crop, the benefit to both crops might have been much en- hanced. Jt appears from the Experiments of Mr. Hassenfratz, cited in Dr. Thomson’s System of Chemistry, that the.times in which manures begin to produce their effects, and the length of time for which they operate, are proportioned to the degree of putrefaction under which they are ‘applied. Having manured two pieces of the same kind of soil, the one with a mixture of dung and straw highly putrefied, the other with the same pro- portions of dung and straw newly mixed, and the straw almost fresh, he observed, that during the first year, the plants which grew on the putrefied dung produced a much better crop than the other ; but the second year (no new dung being added) the ground which had been manured with the unputrefied dung pro- duced the best crop: the same thing took place the third year ; after which, both seemed to be equally exhausted. Ano- ther experiment of the game chemist made on shavings of wood, places in a striking light the slow progress of the effects of ma- nure which decomposes slowly. He allowed shavings of wood to remain for about ten months in a moist place, till they began to putrefy, and then spread them over a piece of ground, by way of manure. The first two years, this spot produced nothing more than others which had not been manured at all; the third year it was better; the fourth year it was still better; the fifth year it reached its maximum of fertility ; after which it declhi- ned constantly till the ninth, when it was quite exhausted. When dung moderately fermented has been applied to land sown with turnips, it has been observed that the fly is not so apt to take the turnip as when the dung has been fermented in a de- ficient or excessive degree. This is not to be attributed so much to the vapour from the dung being offensive to the fly, for a high heat is congenial to the insect, as to the plants making such quick progress from a free but well-tempered excitement as to get into the rough leaf and past danger before the insect lights upon it. In the sixth place, the abstract above presented from Sir H. Davy’s Lectures, notices a main objection to the expenditure of HOMESTEAD MANURE. ; 19 _ lung on land when but slightly fermented, which is, that weeds Fy spring up more luxuriantly when dung im that state is applied. By way of repelling this objection, the Professor merely alleges, that “ it can seldom be the case to any extent that seeds are carried out in the dung. Not to dismiss an important objection without obviating it,— If the system of using composite dung when green, or but slight- ly fermented, be adopted, the following precautions and limita- tions seem necessary in collecting the materials. From the dunghill intended to be so expended must be excluded many things naturally mixing in the refuse heaps of a farm and gar- den. These things may be comprehendéd under three classes : —1. Weeds; 2. Vegetable remains, containing woody fibre; 3. Particular kinds of dung which are pernicious without being pulverised. But articles which contribute so materially to the mass of vegetable manure need not be lost. Let one dunghill be set apart as.a rot-heap for such substances as it is requisite entirely to decompose before they are carried to the land, par- ticularly weeds and woody fragments. The heap to which litter‘and dung is carried for use when _ slightly fermented should be kept at a distance from the rot-heap, and nothing should be admitted into it but what is easily solu- ble from the effects of heat and moisture. An intelligent friend named in the Preface to the “ Practical Gardener,” as a contributor of several valuable additions to that posthumous work of Abercrombie—who derives his opinions on practical points from a long course of experience in the di- rection of large horticultural and farming establishments, en- lightened by a general acquaintance with the best authors on ru- ral economy—has communicated to the Writer several observa- tions in respect to the application of dry litter and unfermented dung on land. In the above review of Sir H. Davy’s system, under the head, Improvement oF Sorts, [X. 17, “ Dry straw and spoiled hay,” a method of employing these materials without fermenting is suggested. If the expense of cutting dry straw by a machine to prepare it for manure should not prove too great, it may be worth the cultivator’s while to employ it as above recommended on LAND UNDER THE PLOUGH OR SPADE, provided the soil is rich enough in vegetable aliment to sustain the expected crop without anu immediate benefit from the manure. Manure so applied will rather assist the second crop than the first. ; Incontestable Exception. In land to be sown with barley, lit- tery unreduced dung has a remarkably bad effect. With regard to pasTurRgs, the agriculturist above alluded to entertains, from experience, from observation, and from reason ing on theoretical grounds, a decided opinion, that neither hay nor straw, nor any haulm, should be applied to the surface of | ' . 80") MANAGEMENT OF grass-land before it has undergone a sufficient fermentation to ensure its easy and expeditious decomposition when «spread abroad. On grass-land, the object of combining as much as pos- sible of the manure with the soil is more likely to be promoted by spending it in a stage already advancing toward complete de- composition, than by lodging on the ground strawy litter not at — all fermented ; while the face of the verdure will not be so long — encumbered. Nor will the gaseous matter escaping from litter left slowly to rot in.a pasture more benefit the land than if it had exhaled from a dunghill in the homestead. It is altogether dif- ferent in relation to land under the plough or spade: by turning in the manure as soon as circumstances may render fit, when fermentation has just commenced and the long litter is some- what reduced, the fluid matter is secured for the enrichment of the land without any extraordinary pains and without injury, be- _ cause the crop is afterwards put in: the gaseous matter is also secured 5 but whether permanently or not, may be doubted, be- cause substances disposed to take a volatile form will fly off whenever the bosom of the soil is opened to the air by tillage. In order to preserve the fluids draining from dung, without the expense of a reservoir, or the trouble of laying a terrace of mould as the site of a dunghill,—the composite dung or litter, previous to fermentation, may be laid in heaps on the field where it is to be spent, and then brought to ferment by the same means as dung preparing for a hot-bed, and kept fermenting for about the same time before it is spread. ‘This might be done even on pasture : but it is worth consideration, 1°. Whether the spread- ing of a substance which has to go through the whole process of fermentation over a surface of grass may not materially injure the life ot the health of the herb. 2°. Whether a smaller pro- portion of manure, if laid on pasture in a state approaching that of vegetable mould, may not be more beneficial, by soon mixing with the soil, and doing no injury to the crop, than the larger quantity of litter, which has to lie for a length of time heating and partially rotting before it is dissolved and imbibed by the sward. This is stated as a subject for further inquiry, in deference to the Professor: but a practical farmer who has tried the matter is decidedly of opinion that dung must be considerably reduced to be of unqualified benefit to pasture. _ To obviate one principal objection against employing strawy unfermented dung as a top dressing for pasture, Sir H. Davy proposes to carry back to the dunghill the long straws and un- fermented remnants of vegetable matter. ‘This mode of re- moving the encumbering litter would be attended with an ex- pense far beyond the value of the strawy refuse : and yet, were such litter left in a pasture after the new herbage shoots, the husbandry would be foul; and, in the loss of manure, with in- jury to the crop, doubly unprofitable. 4 % J i HOMESTEAD MANURE,» Si _ With respect to the dung of cattle ina green or unfermented state, it is said, under the head Improvement oF SoiLs, X. 6. as a quotation from Sir H. Davy: “If the pure dung of cat- tle is to be used as a manure, like the other species of dung which have been mentioned, there seems no reason why it should be made to ferment, except in the soil.” The first sround of exception to this, is offered by Mr. Wright’s experiment already quoted, proving that green cow- dung is pernicious on land sown with barley. As to sheep-dung, deer-dung, hog-dung, and horse-dung, in a green state, they may be applied, either singly or mixed, to ploughed land in general with a good effect. The hot and fiery kinds of dung should not be laid on pasture, unless tempered by mixture with the colder sorts, or unless the quantity applied ean be minutely divided so as to facilitate both the equal dis- tribution of it over the field, and its speedy sinking into the sur- face. Thus the dung of hard-fed horses should not be used green on pasture land, because of its heating quality ; but it may be turned into ploughed land with obvious advantage. If, how- ever, an arable field is in want of instant benefit from manure, such part of the manure as consists of horse-dung ought to be fermented ; because the dung of an animal not chewing the cud contains much undigested matter,—straws of grasses, or grains of corn, according to its food, broken into small parts, but not dissolved: whereas the dung ‘of most cattle that ruminate soon putrefies in the soil. Cow-dung alone forms an exception ; some of its peculiarities are noticed below, Sheep’s dung may be applied green, either to pasture or ploughed land. ‘he urine of sheep, richer than that of other cattle, except perhaps deer, is of equal utility with their dung. The dung of deer is as well adapted to improve pasture with- out long encumbering the surface, as that of sheep. If sheep are folded, the sooner the dung is ploughed into the land the better. Neat’s dung in a recent state is cold. Another cause of its bad effect alone is its tendency to cake, so that it has a tenacity like that of clay: hence it is not easily pulverized, so as to be equally distributed over a field, and intimately blended with the soil. When laid pure in a mass, it does not naturally heat ; but it may be brought to ferment by a mixture of straw and hot dung. If kept for a long time unmixed with other dung, it _ undergoes a change within itself, without losing the vegetable part of its substance by fermentation, When the dung of oxen _ Is prepared as the main ingredient for exotic fruit-bearing shrubs, it should be kept for three years by itself, to lose its tenacity : after which period it is full of aliment for plants, perfectly L \ ' ; AMG aa divested of that rankness which is offensive to the roots 0 trees, and easily pulverized. a: Wei Where several dung-heaps are collected near a homestead, — it may be proper to distribute the litter to each, with some attention to the kind of crops for which the manure is to be — spent. Stable dung, also the straw of corn and pulse crops, might be set apart to augment the bulk of manure preparing for arable land; offal hay, the sweepings of the hay-loft, and the decayed substance of green crops, would revert, with much fitness, in the shape of compost, to fields of pasture, This is only an extension of the principle on which malt-dust has been employed as a manure for barley, with peculiar success. Lands laid down under grass merely to prepare them for corn should be treated when manured as arable, in respect to the quality of the manure, especially when on the point of being broken up. The following practical outlines on important points in the Management of Manure from the Homestead are drawn from a recent work of great authority, to which e have more than once appealed. As far as they correspond with communications already given, it is a satisfactory corrovoration ; if they manifest any shade of repugnance to practices or opinions detailed in this treatise, the circumspection of the Reader will be usefully awakened. “In the Southern counties of Scotland at the present time, the crops are cut very low: the straw and haulm is used for absorbing the excrementitious matter of domestic animals. The juices of the dunghill are carefully preserved from waste ; while the heap is greatly augmented and enriched by the con- sumption of green clover and turnips, and made to undergo a greater or less degree of fermentation and putrefaction accord- ing to the crops and soils to which it is to be applied. Dung is never laid on foul land,—very rarely on pasture or hay grounds, as in England; but it is distributed economically over a third or fourth part of the land in tillage, and thus over the whole farm in regular succession, at a time when the soil is in a state to receive the greatest benefit from its operation, and in that stage of a rotation when the land most demands that method of recruiting it. “ For a drilled turnip crop, it is indispensable that the dung be well rotted, and capable of instantly-hastening the growth of a plant which in its infancy is exposed to the attack of seve- ral deadly enemies.* But an abundant crop of potatoes may be— raised by the use of fresh unfermented manure; and for clay — soils generally, whether the manure be applied to a fallow under ‘ -preparatfon for an autumn sowing of wheat, or for beans, as it has a much longer time to decompose in the soil, a less degree ¥ of putrefaction is required than for a turnip crop.”* : Recapitulation.—¥ or the management of manure from the homestead, the following rules of practice seem to result from _ the preceding discussion of theoretical principles, in connection with some recorded experiments. 1. To ferment dung-heaps from which mown or pulled weeds and woody fibrous refuse are excluded, until they have lost one- third of their weight; and even this in districts where manure is scarce, and where the motives for spending it in the most economical way are the strongest. ‘To ferment it to this mini- mum degree previously to spending it on ARABLE land in au- tumn, or at a season when some time will elapse before the seed is putin. ‘To ferment and purify itin a greater degree when intended for use just before a spring sowing. To fermentdung to be spent on GRAss-LAND until the strawy materials begin to dis- solve. 2. To ferment dung-heaps in which weeds and fibrous vege- table remains or woody offal are laid to rot, until the roots and. seeds of the weeds and the fragments of woody matter are de- composed. This kind of heap may properly be set apart for pasture as far as it will extend. ) 3. To save the drainings from dunghills as much as possi- i ble. 4, To disregard the loss of gaseous and volatile matters, both from the dunghill and from the surface of land ; and to estimate it rather as a benefit, for the reasons given under “ Fallowing.” (pp- 28—31.) To make trial, nevertheless, how far a covering of earth upon a dunghill can be converted into a manure, where the matter of a dense and rapid exhalation may seem worth in- tercepting. 5. To avoid fermenting the dung-heaps described under 1, until the fibrous texture is totally destroyed, and the mass of ma- nure becomes cold and soft,—where the manure is to be expend- _edon a large tract, particularly on lands under the plough,— chiefly for these two reasons: first, to obviate the loss of fluid matter where a reservoir cannot be contrived ; and secondly, on account of the exhaustion of the fermenting principle, which would be usefully set in action in foul soils ; rather than for the other causes theoretically assigned in the Llements of Agricultu- ral Chemistry : because, admitting a principle urged by. Profes- sor Davy, meriting a distinct notice, that the “ ultimate results of excessive fermentation. are like those of combustion,’ it is ’ es 4 i; 1 |. * General Rep ort on the Agricultural State of Scotland, in five vols, 4to. HOMESTEAD MANURE. | 83 * 84 MANAGEMENT, &c. reasonable to conclude, from the experiment related above, on — the ashes of 15 cwt. of Barley Straw, that if the quantity of burnt-straw had equalled the weight of strawy dung, the ashes would have surpassed the strawy manure in fertilizing effect. The ashes of various burnt vegetables are celebrated for their fertilizing power. To return to the object of checking fermenta- . tion bey ond the proposed degree, spread the heap abroad. Heavy watering will at once abate the heat; but the heat will after- wards revive with increased fury, unless the stack be either trod down to exclude the air, or scattered and partially dried before it is again allowed to ferment. 6. In gardens, and on grounds cultivated on a small scale, and even on arable farms where rest by summer fallowing .can be superseded by a constant full supply of manure, the utility of rotted dung is far above that of strawy unfermented litter or slightly fermented dung; because the latter is a nidus for in- sects ; also because putrefying remains, if in contact with grow- ing plants, must tend to injure the health of many species, and to deteriorate the flavour of the edible parts of plants, and espe- cially of esculent roots. Page 26. “By Farrowrne.”]—While this Treatise was in the press, an ori- ginal critique on the ‘ Elements of Agricultural Chemistry,’ appeared in the ‘ Farmer’s Magazine.’ The Conductor of it, who possesses great advantage for comparing the projects of theory with the results of practice, has ex- pressed a deliberate dissent from Sir H. Davy’s doctrine ‘ on Fallowing.? The grounds of opposition there taken coincide so closely in a few fundamental . points—and so substantially in their tenor and conclusion—with the observa- tions made on the same subject in the preceding pages, that it may be expe. dient to state that the passage in the Treatise (pp. 26—34) was printed off before the publication of the Magazine, and that the MS. of it had been in the hands of some friendly critics sufficiently long to establish for it an inde- pendent origin ; having been dissected by a surgeon, weeded and pruned by a gardener, and examined for a degree by the principal of a college. This still leaves to the critique in the Magazine all the force of a corroborating authority; in which light I adduce an extract from it, with much satisfaction. The coincidence chiefly to be remarked, is in admitting many of the Lec- turer’s positions advanced as chemical facts, and in deriving from them counter arguments. But the points on which the Reviewer enlarges are not the same, and some forcible passages in his parallel course struck me as;new, the natural effect of free deduction without communication. f But with regard to his doctrine concerning fallowing, we differ from him entirely. He thinks a clean fallow ‘may be sometimes necessary in lands ‘ overgrown with weeds, particularly if they are sands which cannot be pared * and burnt with advantage ; but that it is certainly unprofitable as a general * system of husbandry.’ Now, we think naked fallow to be chiefly useful on strong tenacious clay soils ; and although it be true that the mineral earths in the composition of the soil, attract no new principles of fertility from the air, there are inferences deducible from his own doctrines which seem to recom. mend fallows for such soils. Waving the destruction of weeds, which can be more effectually accomplished by fallow, than by any drilled or green crop, we observe, Ist, That by exposing soil in large clods, to the action of the sun’s rays, in spring and summer, it is heated to 120° of Fahrenheit, and often much more. By this its moisture is exhaled, and the clay comes somewhat to resemble that described by our author, which had been burnt with fire. It becomes more brittle, and less apt to cohere with subsequent moisture. Hence, the oftener our carse soils are treated with fallow, the more friable they be- come. 2d, When our author pronounced this severe censure upon fallows, he seeims to have forgotten what he so often states in the course of his work, that after all the soluble matter in a soil is exhausted by cropping, there still remains much charcoal, the remains of woody fibre; that this charcoal im- bibes a large proportion of oxygen when the air has access to it, but that it remains inert in the soil, unless a new fermentation be excited in it, by various means which he describes. Now, in clay soils this charcoal is effectually ex- cluded from ‘imbibing oxygen from the air, but is brought into a condition to do so by fallowing. The effect of this, and of its imbibing moisture, is its gradual conversion into carbonic acid, and carburetted hydrogen, for the nou- rishment of plants, Aceordingly, experienced farmers have assured. us, that i poate ai they have known land that had been long manured, and afterwards exhausted — by cropping, have its fertility more restored by a fallow than if it had res ceived a full dose of putrescent manure. Their experience may be accounted for by data furnished by our author; and we are sorry that, in this case, his conclusions seem to be in direct opposition to his premises. We so far, Lowever, agree with him, that fallows are sometimes too often repeated, especially on sandy soils, where drilled crops may, in general, serve their purpose ; but on cohesive soils we hold them to be occasionally indispensable.” _ es Farmer’s Magazine, No. LXIV. (dated 6 Noy. 1815.) p. 488. re P. 50. Zé is decomposed, &c.|—The sulphuric acid in gypsum will also com- bine with ammonia. Manufacturers of sal ammoniac fave availed them- selves of this, afterwards disengaging the ammonia with muriatic acid, This strengthens the motiyes for trying with gypsum composts containing animal filaments. Composts, rightly proportioned, are in general move effi- cacious than any simple manures. P. 76. The fifth argument is entirely practical, and the authority adduced in ats support one of the highest.|\—The Author of the Lectures might have cited another great name, as an advocate for expending putrescible manure in afresh state. From the ‘ Hints on Agricultural Subjects,’ (by J. C. Curwen, M. P. of Workington Hall, Cumberland, Esq. 2d edit. London, 1809,) it may be collected, that the practice at the Schoose Farm was shaped upon this principle, but with many capital divergencies from the broad and indiscrimi- nate track which owes its ease and simplicity to the nature of mere specula- tion, - , “ 1 should say, . .. bury the manure as deep as possible, and then sow the turnips directly on the manure, leaving twenty-four inches between the rows: this will afford ample room for the plough to work, which will not only admit complete cleaning, but in the operation furnish that degree of nourish- ment to the turnip, which in very dry seasons would be highly serviceable, and contribute greatly to ihe weight of the crop” Hints, p. 221. ie * This method would also permit of fresh stable-litter being made use of, without the necessity of its undergoing that degree of fermentation which reduces it at least one-third in bulk; and, in my opinion, still more in effi- cacy... I have taken great care in having horse and cow dung mixed in equal quantities, and the muck-heaps formed into pyramidal shapes, so as to adnait of their being easily covered with earth, which is collected for this purpose.” from head-lands and ditches. This method prevents the evaporation; and the gas imbibed with the earth makes it equally valuable with the dung. The making what is called manure pies is a common practice inIreland. It serves greatly to increase the quantity, which must always be acceptable to the far- mer.” Hints, p. 222. - Mr. Curwen’s method of applying manure in the field is but part .of a sys- tem; therefore, before giving that method, it will be proper to state, that his first principle for bringing foul land into good tilth, and for superseding a na- ked fallow, by the relief of alternate green crops, is,—to leave such a space between the stitches of the green crops as will admit of working both with the plough and hoe throughout the season; a space double to what is com- monly allowed. He holds, that by constantly turning the vacancies between the rows or beds, in every direction, he can in dry weather procure for the plants something like a compensation for rain, in the evaporation of moisture from the earth. “ The first day’s exhalation from ploughing is in the propor- tion of 950/4s of water per hour from anacre. The evaporation decreases on the second day a third part, and continues to diminish for three or four days according to the heat of the weather, when it entirely ceases; and is again renewed by fresh ploughing.” Hints, pp 211, 212. “ A field of cabbages were this year set on a very strong stiff clay, which ‘a previous to their being planted was in high tilth, The severe drought which . succeeded the rains that fell soon after setting, baked the ground perfeetly | hard. The plants made little or no progress; they were seen by a friend of mine, on Monday the 26th of May, as I was commencing the breaking of the ground with the ploughs. They were worked for the whole week. On the saturday they were seen again by the same gentleman, and he could scarcely be persuaded they were the same plants. The week had been very dry, with a hot sun, and strong north-east winds. The crop of last year was allowed to have | . been a very extraordmary one, and weighed thirty-five tons and a half per acre. Some of the cabbages were fifty-five pounds ; they had only fourteen tons of manure upon the acre. My second principle is, to bury the dung as deep as possible, in order to retard the evaporation, and keep the heat in the ground, by preventing the atmosphere from acting upon it. It is a point to be particularly attended to, that the manure should be kept quite dry, which is done by having a deep trench in the centre of the space between the rows. ! By these two combined principles, I expect 1 shall succeed in obtaining equal al crops, though but one half, and in some instances, only a third of my ground . is occupied. To pronounce decidedly that this will be the cause would require A further experience than 1 can pretend to boast of. So many circumstances ought to be taken into consideration in every experiment, that many trials must be had before it can be pronounced altogether successful. 1 have the i. testimony of a very meritorious agriculiurist, who las made several experi- ments upon this plan in garden husbandry, and who states the most favourable i result. Whe gentleman J allude to is the Reverend E. Ellerton, of Colston, 1 near Ulverstone. ‘To such as have no option, like myself, but are obliged to set their potatoes on wet ground, the plan I have followed has in one parti- cular been found to answer a most admirable purpose. it keeps the potatoes so perfectly dry, that in this unparalleled year of wet, where in most dry grounds the loss by decayed potatoes has been very great, | have had no loss - whatever. I cannot boast of the weight of my crop, but indeed it was not to Yen be expected, being set a month later than the usual time, and the vegetation destroyed by the frost in the very beginning of September, which is a month before what is common. | am by no means discouraged or dubious of the prin- ciple on which it was undertaken; and I hope to give it a very fair trial”, Hints, pp. 213, 214. ** Dung, and all the animal mixtures, I bury as deep as possible, taking care that they shall lie deep. Lime, (the little 1 use being solely in compost,) p schistus, ...sand, &c. are used for top-dressings.” Hints, p. 222. “1am strongly inclined to believe, that where the ground is laid dry, that manure can scarcely be deposited too deep, by so doing the evaporation is retarded, and consequently, the manure continues for a greater length of time to fur- nish nourishment to the crop.” Hints, p. 268. ** The experiments I have made tend to establish the double advantage of well cleaning and working the ground. First, as it frees the land from weeds ; and secondly, as it conduces to the growth of the crop. It affords likewise a very strong demonstration in favour of using the manure in its freshest state, by which not only the great usual expense of making dunghills will be saved, but the manure made to extend to the improvement of a third more land. “« Most of ‘the farm I occupy was in that state of foulness as to require, ac- cording to general practice and opinion, a succession of fallows to clean it. Be- ing unwilling to adopt a system which is attended with such loss, 1 determined to attempt to clean a part of it by green crops, and for such purpose to allow a much greater distance between the stitches than trad ever been in practice. My first experiment on this plan was made on a crop of cabbages; they were planted in a quincunx form, allowing four feet and a haif between each plant, in order to allow room for the plough to work in all directions. 1 adopted this plan of field husbandry, as affording the greatest facility in cleaning the crop, though I believe it was never before practised. Two thousand three hundred and fifty plants were set per acre (eight thousand is not unusual in the com-_ mon method,) and each plant had, by computation, an allowance of a stone of — manure, or less than fourteen tons per acre; though the common quantity is generally from thirty to forty tons per acre. The manure was deposited as — deep as the plough could penetrate, drawn by four horses, and the plant set — directly above it. “ The plough and harrow, constructed to work betwixt the rows, were con- —~ atantly employed during the summer, and the grownd was as completely freed > roe aie 8S ADDITIONAL NOTES. tty from weeds as it could have been by a naked ‘fallow. The very surprising” weight of my crop, which in October was thirty-five tons and a half peracre, — and many of the cabbages fifty-five pounds each, were matter of surprise to all who saw them, as well as to me; and I could assign no satisfactory reason for the fact. The quality of the land was very indifferent, being a poor cold clay, ~——the manure was very deficient of the usual quantity,—the plants when set by no means good,—in short, there was nothing to justify the expectation of even a tolerable crop. 1 did not find any thing in the accounts from cultivators of cabbages to afford me a solution of my difficulties, or any clue to explain it. — By mere accident I met with the Bishop of Landaff’s experiment, ascertaining the great evaporation from the earth, as related in his admirable Treatise on Chymistry ; singular as it may appear, this very interesting’ experiment had re- mained for thirty years without any practical inferences being drawn from it applicable to agriculture, It appeared to me highly probable, that the rapid advance in growth made after the hoeing of drilled grain, was attributable to the absorption of the evaporation produced from the earth, and was the cause of the growth of my tabbages. With great impatience and anxiety, as I had the honour to inform you last year, L looked forward to the ensuing season to afford me an opportunity of continuing my experiment. Ihad long been a strenuous advocate for deep burying of manure, though my sentiments rested chiefly on opinion ; this appeared to open a field for incontestable proofs of its advantage. My cabbages were last year planted on the same plan as the for? mer year. Fortunately I extended the same principle to my potatoes, which I was obliged to set on wet strong ground, from want of a choice of land. My annual quantity of potato ground is from sixty to seventy acres, They were set in beds three feet long, and two feet broad, leaving four feet anda half be- tween each bed lengthways, and three feet endways. On each acre there were 1230 beds, and 6150 sets, or five to each bed, viz. one at each corner, and one in the middle. The sets of potatoes, when planted according to the usual most approved practice, in three feet stitches, and nine inches apart, amount to about twenty thousand. In the present, and indeed in all seasons when potatoes are scarce, the saving in planting is a considerable object. A great advantage also arises in being able to keep the potatoes and manure from wet. In the late uncommonly wet season [ sustained little or no loss in my mode, which was not the case in many of the driest grounds. This plan unites hand hoeing with horse culture, and will be found serviceable in wet soils. * The lateness of planting, together with the premature frosts, prevented my forming a fair judgment as to the quantity per acre which might be obtain- ed by this method. My view in fixing upon this plan was, to enable me to judge of the effects of evaporation, by being able to continue my operations for a longer period. I have no doubt but that in common seasons, notwith- standing the increased distance, the whole ground would be covered. “« My experiments on cabbages this season, commenced by planting them early in April. From the rain which fell subsequently, and continued till the beginning of May, succeeded by severe east winds, the earth became so hard and baked, that the plants had made very little progress. ' , “ In the first week in June the ploughs were set to work: as they started, Mr. Ponsonby, of Hail Hall, was.present, and saw the crop; it was with dif_i- culty that the ground was’ first broken, but by the end of the week it was brought into fine tilth. Notwithstanding the whole week had been dry, with a strong sun and severe east wind, yet such was the progress in growth of © the cabbage, that when seen again by that gentleman on the Saturday, he could scarce be persuaded they were the same plants. “ During these operations I had been making constant experiments with glasses, contrived for the purpose, to ascertain the quantity of evaporation from the land, which I found to amount, on the fresh ploughed ground, to nine hun. ~ _dred and fifty pounds per hour on the surface of a statute acre, whilst on the ground unbroken, though the glass stood repeatedly for two hours at a time, there was not the least cloud upon it which proved that no moisture then arose from the earth. * The evaporation from the ploughed land was found to decrease rapidly af- , ter the first and second day, and ceased after five or six days, depending on / ADDITIONAL NOTES. 89 ‘the wind and sun. These experiments were carried on for many months. Af- ter July the evaporation decreased, which proves that though the heat of the atmosphere be egual, the air is not so dense. The evaporation, after the most abundant rains, was not acvanced beyond what the earth afforded on being fresh turned up. The rapid growth of my potatoes corresponded perfectly with the previous experiments; and their growth in dry weather visibly ex- ceeded that of other crops where the earth was not stirred.” Hints, pp. 269. . 274. “ The evaporation from dung is five times as much as from earth, and is equal on the surface of an acre to 5000 pounds per hour. By making use of dung in its freshest state, the farmer may extend his cropping to one-third more land with the same quantity of manure. It is with regret that 1 have viewed in many parts of the kingdom the quantity of manure which is exposed on the surface, and tends to no good. F am strongly of opinion, that in alls light soils, if the manure was buried in trenches as I propose, and the turnips sowed above it, that more abundant crops would be procured. By cleaning. with the plough, great advantage would be derived to the crop, from the eva- poration yielded by the earth. Hot manure might also be used. By fermenta- tion dung is reduced to one half its bulk, and its quality reduced in a much greater proportion. The manure now commonly taken for one acre of broad- east, would if deposited whilst hot in drills, answer for four acres, and the crop produced be much more.” Hints, p. 275. These extracts embrace three important things: 1. Gren crops WITH WIDE INTERVALS. 2. THE APPLICATION OF PUTRESCIBLE MANURE IN ATRESH STATE, 3. "THE PROPOSED EXTENSION OF THIS PRACTICE TO LIGHT SOILS. In relation to the first head, the copious evaporation of moisture from new- ly turned earth is an important discovery. Whe wide intervals in the green crops are to provide for its free application. The intention is judicious: but in leaving intervals wide enough for a plough to work, the sacrifice of area may outweigh the benefit, especially if the plants are not capable of reaching a size in proportion to the space between them. The large field cabbages are perhaps most likely to afford a compensation in weight. In what degree the usual field crops would be thus diminished is highly requisite to be computed ; for if the produce from an acre is diminished every alternate year in a mate- rial proportion, the sacrifice in seven or eight years may be equal to one na- ked fallow in the same time, or may exceed it. When potatoes are planted: | iene Intervals of four feet and a half. <¥n the manner above described, | 3 feet by 2 | | 3 feet by 2 | The unplanted ground is as 11 to 2; and can it be expected that the roots will send out runners halfway across the wide intervals? or that the weight of -erop can sustain a competition with one raised from closer beds? We” may eonclude that further experiments produced the conviction that such green fallows are on the average unprofitable; for at the date of the letter cited in the preceding treatise, (p. 31. n.) The President of the Workington Agricul- ‘wral Society had become reconciled to a summer fallow in rotation with white crops, on a clay soil. But the history of experimental farming is a history of revolutions in which practices which seem to be the very same are alternately abandoned and resumed—seem to be, but they are not, the very same ; for the circumstances of positive knowledge are different by the advancement of a ‘stage, and the preponderating obstacle which last turned the scale, is removed by a new contrivance. Thus, a clay soil can be rendered fit for green crops by a top dressing of clay ashes; (T'reatise, p. 54.) and whether the system of M ae *jaQJ AAI} JO sjeasdqUy a j 90 ADDITIONAL NOES. ie bs summer fallowing is entirely superseded by this resource, will depend yew upon a fair comparison of the expense and benefits found to attend both courses. The letter of Mr. Curwen to Mr, Dempster, (adverted to in the preceding treatise, p. 55. n.) has these two passages. ‘1 conceive that I am justified in anticipating a rapid increase of green crops, the means of producing them be- ing now within the reach of every one.”—* I do not think I am too sanguine in viewing the general adoption of the system of surface soil and clay-burn- ing, as likely to be the most important discovery for the interests of agricul- ture, that has occurred since the introduction of the turnip into Norfolk by Lord Townsend.” Mi, The second subject which we are stimulated to consider anew by Mr. Cur- wen’s Hints, is, The application of putrescible manure in a fresh state. Tt is plain that all the instances, above collected, of this application relate only to arable land. Now, if we advert to the local climate, and the soil, at the Schoose Farm, we may see causes why such a practice, as part of a system, may confer partial benefits ; and why its positive defects may be compensated, its disadvantages cour eracted. 1. the climate is moist: ‘42 inches of rain fall in the twelve months, whilst in Norfolk they have but 22.” (Hints, p. 211.) 2. The soil is Sa stiff loam, partaking in a great measure of clay.” (p. 262) 3. Deep ploughing for the winter fallow is practiced there; the furrow at the first ploughing for a green crop is described as from 11 to 14 inches deep. (p. 211.) The Author of the Aints notices, however, the objections which the advocates of other systems have made to this part of his: ‘* More diversity of opinion is found to exist as to deep and shallow ploughing than might be expected. I should deem shallow ploughing four inches; medium, six; deep, nine: but every six years I should advise making the winter fallow twelve ; I have found it invariably to answer, and it is with satisfaction I see it becoming very gene- ral in the county of Cumberland.” (p. 237.) To, connect these circumstances.—If strawy litter is buried in a deep fur- row under a drilled ridge, the channel thus created will at least operate &s a drain ; which must be a benefit on a clay soil in a moist climate. Supposing the fresh litter, dung, or animal refuse lying deep from the surface, not to be decomposed till the following season, yet if there be already in the soil suffi- cient aliment of any kind for the plants the first year, the farmer will not be disappointed at harvest time : meanwhile there is a provision of manure for the following year; and the same course may be annually repeated with a di- minished hazard of starving the crop. Supposing, on the contrary, the fresh “manure to decompose in that situation, the first season, the deep burying of it leaves a layer of earth for the growing roots: thus the baneful contact of hot dung, putrefying vegetables, and rank animal fluids, will be eluded. Still let all the accidents be fortunate, some losses and waste must attend this way of depositing manure, either from fibrous matter getting too deep to be acted upon by the atmosphere, or by rich fluids irrecoverably sinking into the subsoil beyond the attraction of annual crops. As to grass-lands, the practice at the Schoose Farm appears to be, to manure these with unputrescible substances, in a shape for sinking presently into the surface ; such as coal-ashes—street-rakings—sea-sand—and schistus (coal-slate)} previously pulverized by mixture with caustic lime, six parts to one of lime. In this, there is nothing to countenance the project of spreading fresh litter on pasture. It may be observed, that although all these articles must improve a soil of clay, yet only the street-rakings can have much power as containin ‘manure for a plant to consume. If clover and rye grass, under treatment whi decidedly improves the texture of the soil, now and then turn out a bad crop, it may be attributed to a deficiency of aliment; plants cannot get plump on @ good lodging, if poorly fed. The least rapacious feeders have some ap- etite. Thirdly, our extracts from the Hints contain this important suggestion: “ E am strongly of opinion, that in all LIGHT SOILS, if the manure was buried in trenches as I propose, and the turnips sowed above it, that more abundant crops would be produced.” ‘The agriculturist who combines knowledge with invention, enterprize with experience, liberal communication with vigilant in- Sn I quiry, and candidly declares the results of his own experiments, will necessa- _ ily frame a system of farming both beneficial to his own estate, and that may _ be transferred with benefit to Jands similar to those which he has long mana- ‘ | who have tried the application of long littery dung, and seen it extensively | tried, on Liga? soins, pronounce decidedly that it is inferior in efficacy to well fermented manure. With regard to the soil itself, the want of due tenacity, _ one of the inconveniences of light sandy land, is increased by loose litter, so that the seeds are more exposed to be blown out, or the plants unrooted. As _ to the crop, it consults the habit of hardly any plant but the potato ; and even for tiis the long litter should be cither shghtly fermented, or but just covered. with earth, that air, heat, and moisture, may help it to decompose. __ P.83. Vo disregard the loss of gascous and volatile matters, both from the ding Mill, and from the surface of the land ; and to estimate it rather as a benvfit.|\— _ One of the priticipal gaseous matters escaping from dunghills and fallows, is, ammonia or volatile alkali. Uhe Author of the elements dwells much on the magnitude of this loss. But what is Ammonia?