U1 NOT THE GliOltY OP CESAK ! HUT THE WEI.FAltE OF It O 31 E. BY II. 13. STACY. FRIDAY, DECEMBER. 23, 1S36. VOL. X No. 49(i I WISH HE WOULD DECIDE. I wish lin umild decide, tn.iinn, I wish he would decide ; l'vo been h bridc'tniid luenly time.', When sli.ill 1 lie a In ide ? Hlv cousin Ann, my sister l-'an, The nuptial Knot line (ii'd ; Yd rome uliat will, I'm pinglo Hill I wish lie won lil ilccitle. He lakes tne to llie pl.iy, mama, He lirini me pretty books, He woes meu'uh his eje., mama, Such speechless lliings lie looks ! Whcnc'r I ro.im nlmi.id, nt home He lingers by mv side ; Vet rome ulr.it will, I'm single still 1 with lie would decide ! 1 llirnw nut many hitils, miiinn, I Fpenk of oilier beaux ; I talk about domestic life, And sing "Tbey don't piopoe." But "li ! Iiowviiii i'.kIi pinom Hiuin, Hie unrrin2 lieart to guide ; Do uli.it I ill. I'm single still I wish lie would decide ! I really shall in'ist, mama, If nothing intervenes, "My brother Thomas questions him, And nk him wh.it he mean". And if he wants to "bie.ik," in.im.i, My pasion or my pi ide, Unconcpicied jri shall scum irgiet 1 uith lie nnulil decide. AGUICUI.TUUAL C1IEMISTKY. "Essay on the vie J Limn as a .Wnnurc. fty Pueis. Translated from the French lm Iluflin, En.. with an Intro diidinn explanatory of the principles of .'igricullural uiumisinj by ,iaiic. kd wick. Ij. li. I).. Professor of JVnl. Exp. Philosophy and Chemistry in Columbia College." Tim Clicmicnl facts anil principles which nre applicable in Agriculture arc neither numerous nor complex. They nro. how ever to In; Iiiund iitily in works (in General Chemistry, in which they nre intimately associated with lows nml phenomena cif n innru abstruse description, nnd in conncx itm, with which they conul mite a science of winch tin1 must learned are till students, nnd to a tl o Mi which, in Its exi-tmg form may require yonrs of clnnj nnd nliriitif sillily. The language, ton. uf Chemistry, winch to those who study it in n regular course, serves ns an artificial memory, nuil iin"ln words ol which call up limp trams nf thought nnd experiment, presents In the uninitiated till t lie difficulties of u foreign tongue. Yet it cannot he tloiilitcd. that the prac tical farmer may derive import h tit benefit from ncqiniing so much of: Inn Imigunge n' wilt i tiublo him to umlcrslmid I lie cheiinc.il explanation of I lie numerous changes which nrc continually taking place in 'to' natural notions which it i his high privilege to call into his service, to direct in part, nnd mod ify in degree. So also are there certain chemical elements and compounds, with the properties of which he ought to he ncqnntn. led if he wish to be able to direct his prac tical skill wit li more effect, even in circum stances familiar to him, hut winch may he absolutely nccpary. it will at any rate pave waste of labor and ltis-s of lime, when the knowledge acquired by practice in one place is to be employed in a now situation, and under a change of circumstances. It is the object of this introduction to ex dibit, in such form as may be intelligible to those who have not uinde general chein istry an object of study, n concise view of such of the laws and lucts of that science, 06 arc nu-niuoiy io-ui uiv oo inu unuiir turifct who may wish to improve Ins prac tice, and which nre more particularly re quired hy those who wish to avail them, selves of the knowledge contained in the subjoined essay. To do this has been found no easy task. It would be in iiself difficult, but to the author ol this iutroduc tion has been more particularly so, ns he has for years been in the habit of imparling instruction to those whose habits of life nnd thoughts nre as remote ns possible from lho6c of the practical farmer; persons to whom the peculiar langnuge of chemistry is an aid instead ofun impediment; and who, with ample time nl their commnnd, have nn opportunity of pursuing the study of the science step by step. Fully aware oflliesc difficulties, both general and pecul iar, this attempt would not have been made, nnd cerlainlv not persisted in, had it not have been for the instances of an intelligent, scientific, nnd successful fanner, who has urged the completion of the task as an ob ject likely to be beneficial to those, who, with perhaps equal zeal and native powers of mind, have not enjoyed, like himself, the advantages of n scientific education. The atmosphere which surrounds our earth is the first object to which otir atten tion should be directed. This is the vehi cle of the moisture, which whether it full in the form of rain or dew, run in streams or issue from springs, is nbsolutely cssen tinl to the success of the farmer's labor. It is also, as wo shall presently see, important to him on other accounts. The grcalcr part of the atmosphere is mode up of a mixture of substances, each of which has tho same mechanical proper ties as the whole mass. These air-like substances are known to chemists by the name of Gases. Of Ihesc gases, two mnku up by far the Greater portion ot ntimiiphcric air, nnd ex ist in it in the proportion of about four to one. That which is the largest in quantity and up nearly 4-5lhs of the whnlo atmos phere, is called, in the Kssay nf M. Puvls, by the name of Azot, but is more usually known in English by the nnmo of Nitrogen. This substance, although in the largest propotion, is the least important of tho ga3. es in its chemical effects. It does not aid in supporting the life of animals, nor in maintaining the burning (combustion) of in flammable bodies. The putt of the atmoephctc which is ab solutely necessary for lliese purposes, is called by I ho iinmn ot oxygen, nml nearly makes up tho remaining fifth part of ntino. pheric nir. In its support of life it nlvvnys, and in maintaining combustion often unites with a chemical element, which is called carbon. This i familiarly known as form iug the principal part of charcoal. In ils union with carbon, oxygen forms a peculiar gas known by tha name of cnrbnnic acid. Carholiinic acid is always found in small qunntitics in the atmosphere, to which it n furnished by the breath ofanimaN nnd the fumes of burning bodies. It is, when in considctablo nuatilities, fatal to the lifo of animals-, but is prevented from accumula ting In an injurious extent in consequence of its being taken up by water; it is there fore dissolved, in proportions about equal to those in which it is formed, by rivers, lakes, the ocean, nnd the moisture of the soil. Water exists in tho atmosphere in the form nf vapour. The great source of this vapour is the extended surface ot the ocean; nnd it is governed hy a mechanical law, by which it is continually tending to distribute itself uniformly over the whole surface of the earth. It may thus exist in ns large quantities over the surface of the drvest land as over that of the ocean iiself. This tendency In equal distribution is continuity counteracted by the changes in the sensi ble heat temperature) of the atmosphere, and of the surface of tho earth, which fol low the alterations of day and night, nnd vicissitudes of the seasons. Hy llicse nl" leriilions and changes, the vapour is caused to lull (precipitated) hi the lorm ol rain, snow, hail, dew, or white frost, nccording to circumstances. A fucIi changes of temperature nrc more frequent on the land than on tne ocenr, the water which lall on the lornier in either ofthese is greater in quantity than that which laws on equal snrlaco ol the latter, rnti, by a wi-e nnd benevolent provision of Providence, the water of the ocean is continually fur nilnng vapour, winch is precipitated on the land for the support of vegetation am the eupnlv ol springs, and whose excess is poured back into the ocean in streams and rivers. Water tin been found hv chemists to bo a compound siib-tnnce, made up of two el ements. One of these, which lorm il-Olhs of M weigh!, is the gas already mentioned under the name ot hydrogen. Hvdrngpii, when Iree is the lightest of all known bndie-, rising or floating in nt iii"-pher:c air ; it not only combines with ovvgcti. to form water, but with enrbnn to form a great nrioly of compounds gase utis, liquid, vi-cid, and solid. It also coin bines Willi nitrogi'ii, and forms a gas known hy the nnini; of ammonia, which is well known bvlhe peculiar smell it gives to spirits of hartshorn tirjttitl ammonia ) Hydrogen also combines with stilpher forming a gie known by the name of stil phurelled hydrogen; this exists in tho at mosphere, hut in such small quantities as only to he detected by the nicu.-t chemical tests. I combine-, in like manner with ! phosphorus, forming phosphnretted hydro gen gas, whoso presence in the air i oc-ca-tonally perceptible. Oxygen, as we have seen, unites with enrbnn to form a gas, which we have called carbonic ucd. Tins receives the latter part, of its name from its similarity in properties to an ex ten-ive c'lis-, nf compound bodies, known oy l no inline ol tne .'rwt. I lie greal'-r pari of these, like carbonic ncid, are com liiiiBtinns nT inflammable bodies with oxy gen. Tho most important of these in rcf ereoco to our present object, nre the sul phnrie and phosphoric neuls; nniiied from the two substances (sulphur and nhospho rus which are their bases. Muriatic acid may al-o be mentioned here, nllliough its composition is of a dif ferent character. Oxygen", united with other bodies 0 form a class of composition .'s of a different character. Oxvgen unites with other bodies to form a class of com pounds known under the ncinc of oxides. The acid- unite with earths, alkalies, and nietnllic oxides, to form a clats of com pounds known under the general name of salts. These arp named from the two sub stances which enter into their composition thus, the salt formed of sulphuric acid nnd tho earth lime, is called sulplmtu of tunc I he tn.istances which unite with acids to form salts, nrc called the basis uf the re epe.clivo salts. Of these bases, the alkalies and earths are the most important. Of the alkalis, it is only necessary to know the names ol two, namely potassa and soda, and to he aware that their distinctive properties, are: to possess nn acrid Inste. a caustic opera tion, to render oils capable of mixing with water, and to neutralize the properties of acids. The earth which chemists call by tho name of silex or silica, it is also almost pure in flint and rock chrystal ; it is also almost puro in f harp colourless sands, and is by lar llie larger part ol sands ol every ilescrip tion. So far as the farmer need know its properties: it is hard, rough to the touch, ha no attraction lor water, which it per. mils to filter through, or evaporate from it with the gicatcst case. It is capable of uniting with the other earths in cein pnund.i which arc called silicates, nml is tttc only earth which enters into the forma tinn of soils iincombined with the others or with other elements. Tho cartli which chemists call by the name nf alumina, is so named because it is obtained by them in a puro form from the well known salt called alum, ol'which it is the basis. Its most marked characteristic is placticity : that is to say, it may be form ed into a pnttc with water, will then easily receive any form which mny bo given it.and retain that form unaltered, even by violent heat. It never exists in soils unmixed, but fn intimate association .villi silica, it is tho well known substance called clay, or argil Iqcous earth. Whito claya of this combi nation arc nearly pure, and coloured clays often contain it with no other addition than metallic colouring matter. Clay re-1 tains tin: plastic property of alumina; it therefore cauccs soi's to ho retentive of inoislure; and, when thev drv, makes them form tough clods or crusts, similar in char acter In sun-dried brick. Soils which contain clay nre often also mixed with sand, or with an excess ofsili ca in grain?, winch does not enter into the compoMlion of the clay. Such a soil is less liable to form a tough crust thnn a pure clay, but it will require a largo pro portion of sand to destroy this proporty al together. Clay mixed with sanuy soils renders them more retentive of moisture. Sand and clay have therefore been used for ma nures for each other; but it may reasona bly be doubted whether all the advantages that ha. been anticipated by some from this process, can be realized, as such a mixture will he merelv mechanical. Loamy soils are generally said to lie mixtures of tand andclav; they initlonlit edly usually contain both these earths, nnd even a lurgo excess nf sand. Hut we shall give reasons lor believing that lontns owe their peculiar value to a combination of clav with another substance, bv which a change is prnduced in its chemical charac ters. Lime is familiarly known to farmers by the same name that is generally used by chemists. It is obtained by the aid of heat from rocks which go by the name of lime stones. These nre combinations of lime with carbonic acid, which is fixed in them by chemical attraction, hut which, when driven off by heat, take? the same as the air of atmosphere, or becomes a gas. This gas frnm this circumstance lias been called fixed air, by which nnnie it is often known when causing the sparkling nf ci der nnd beer. Tho principal part of lime stone is therefore called by chemists carlo, note rf lime. Carbonate of lime is also found in shells, both those of living ani mats mid those which exist in the ground in a fn--il state. Iu the former it is mixed with annual matter, which is more or less separated from the latter nccording to the time which has elapsed since the death of the shell fish. Marl, in the sense in which the term is used by chemists, is n mixture of clay with carbonate of lime. The English writers on agriculture have not observed this dis tinction, and the term is sometimes appli ed by them to a decomnnsed chalk, which may contain In tie or no elny; and rome times to clay w Inch con'anw no carbonate of lime. In fact the nnnie is frequently applied by them to any earthly mailer found below the vegetable soil, which, i cnpable of increasing its fertility. From tin un-npprehension. the sub-lnnces which go by the nnnie of nni'l in New Jersey Marjlmid. unit Virginia, do not correspond wi'h the chenucul defioUinn. b'.n are gen erally bed- ol li-s)l shells ni'ieii m various proportion' with enrihy and mi fine matters ol various kmls. Lime is n -nb-tanco very different in its characters from the two earths of which wo have previously spoken. When pre pared by heat from any nf the original forms of its carbouite, it retains their shape unaltered, but msy have its colour changed and nlwavs loses comidcrnblv in weight. It is now acrid, cnn-nc. and corrosive, and hns soma properties in common with pot ash which nro therefore alkaline. Ol these the most important is, that it unites with acids to form compound" included in the general c!as of salts. Of the salts of lime which are important to tin- farmer, the three principal are the carbonate, which, as we have stated is found in limestone, chalk, shells, and marl; the sulp'iatc, in which lime is combined with sulphuric acid, nnd which in combination with water is the substance en well known to our far mors under the mine of plaster of Paris, or less familiartv by that nf gypsum; the phosphate, which constitutes a largo part ol the bones ol niumais. Lime, iu lis caustic stale, has the property of rapidly decmnpo-ing vegetable and ani mal subs'tauco. thus hastening the natural processes by which they are finally destroy ed; or, to speak more properly, have their elements resolved into new combinations. The otVonsive and unwholesome gases, which nre given out by this composition are absorbed by the lime, and prevented from mixing with the air. The same prop, crty is possessed in a less degree by the carbonate of lime, and probably by its oth er compounds; but in order that cither this cartli or its compounds shall manifest this property, or they must be in small fragments, or, which is better, in fine powder. Wet sand and plastic clay, and those soils to which they give their characters, also possess the property uf absorbing gas es; but they have this in a very inferior degree to lime and its compounds, As the ga-es generated by the decomposition of vegetable and animal substances firm a large part of the necessary food nf plants', it is obvious that a soil which contains the carbonate of lime, may retain ami store them up for use whito they will be lost in soil of a different character. Carbonate of limo may also bo made an important article in the preservation of the most valuable parts of putrescent manures, uiiiii niey can uc applied to uie sou. in this way marl is applied to u great extent in China ; tho night soil cf their numerous population is there formed into cakes like bricks, with mnrl,anil thus loses its offensive smell ; but when these nre applied as ma nure to the land, they give out llie gases again ns they arc requrcd for the nourish' incut of plants. So also in Norfolk, the site for dunghills is prepared by n layer of marl, winch is incorporated with the manure from time to time, and retains the gases which would otherwise be loit. Lime may therefore be applied in its caustic form in some cases iu Agriculture, fur it will hasten thu decomposition of an. imal and vegetable matters which might otherwise be inert ; it will also neutralize acids, which experienced farmers well know to exist in many soils, which they in coliscqetirc call sour. Hut the latter pur pose will be answered ns well by the car bonate of I line, which may bo applied as it exists in marl or shells, or at it may be prepared by grinding limestone. Caustic lime is also dangerous in its npplicaton. for it will corrode and destroy living vegeta. hies, nnd hasten tho decompositon of tho vegetable matter of I lie soil to such n tic. gree as to injure its fertility. Except up on turf-bigo, and land loaded with timber not wholly decomposed, quick or caustic lime ought not to bo used ; but to bum lime, and then bv slaking to reduce it to the form uf fine powder, winch is speedily car bonated by exposure to the air, is a more ready, and generally a cheaper mode of ob taining the carbonate in a convenient form than to print limestone to powder in mills. Yet for mativ of the most valuable uses of lime in agriculture, the latter method, if as cheap. vo. .! answer as well. Lime slowly combines with the cartli silicn.and produces n compound very differ ent in chancier from either. It is this, to cite a fact in proof of our statement, which gives the hirdncss and solidity to nncicnt mortar. The carbonate nf time will serve to form tliH compound; and thus, when it has had time to act upon sand, it renders a Mhcious soil more retentive of moisture: while, if applied to clay, by combining with silicious matter.it renders it more friable ; and ii is to the formation nf this compound tiv slow degrees, that we are inclined to as cribe llie valuable mechanical properties of of Inamv soils, and the gradual amelioration prnduced by tho u--c of lime, marl, and shells as a manure. licsule? silica, alumina, and lime, an earth calleJ magnesia is likewise found in some soils. It is also in the form of carbo unto, a frequent constituent uf limestones. Hie earth has ninnv properties, in common with lime; like lime it is capable of neu tralizing acids ; and when deprived of car bonic acid by heat, corrodes vegetable sub, stances. It probably also hastens putrcfac tinn, nnd both it and its carbonate are ca pable ol absorbing the gasscj let loose in thnt nntu-al process. It is however of lit lie interest in agriculture except as a part of some of these limestones which are used ns manure. These ifapplied in largo quan I. ties, are sometimes very injurious to veg etation : the reason ol this is, that mag nesia iloe-- not ropa-" to the state of carbo mile ns rapidly a- lime, and therefore re tains its corro-ive nil u lil v long after the lime has again lo eome mild by the union of carbonic acid. Iu less quantities, however, the magnt'sian Inneslous may serve as manure, but their application requires great ciiutinu, particularly when the quantity of niagirsiu miuur.ts to per cent. All of the limplesubstancs we have men. tinned, except, perhaps the last, either top nrate or in various -tales ol combination exist in plant. Tin manner and etiarac ter of the combination is influenced by the vital 'iciion ot'ilie plant, which causes them to form compounds often in direct oppnsi tinn to t lie manner in which the ordinary laws of chemistry would direct. It thu happen that so soon as the plant ceases to live, the-e chemical laws being no long er impelled, begin to exert their influence and if it be in in such a stnte ns will admit of I lie several elements acting readily upon each iither, n decomposition more or less rapid, of the vegetable structure ensues It is. a law ot chemistry that its action is always aided by bodies being in a fluid state, nnd the action is often impossible when the bodies are perfectly free from moisture- Hence the direct chemical ac tion, and consequent decomposition takes place with greater c rtainty and more ra inditv in green, tuicv, nnd succulent vege tables, than upon those which have been deprived ot moisture enner naturally or artificially. Thus, grass, if heaped up in a recent state, decomposes, and, if but par tially diied, is healed, and may even take fire, bvtbe chemical action of ils elements: while, if dried by exposure to tho sun nnd air, and then laid up in a dry place in the form of hay, it is almost indestruclable. A moderate degree of heat and access lo air are also ncccsarv to promote the chein ical action liy winch decomposition is ef- lected. This decomposition is often altcn ded with motion among the parts; and al ways if the mass lias a liquid form, as the expressed juice ofvegctables, or in the steeps employed by distillers and brewers it coos in general terms bv the name of fermentation. When tho vegetable matt&r abounds in starch, the first change is the conversion of tins principle into sugar. Sugar, if thus formed, is next converted into alcohol, ns it is, if it prci iouslv existed in the plant. The presence ofalcohol gives the liquid in which it exists the character of vinious liquors, and if throe nru permit led to remain in a turbid state, a forth" fermentation converts them into vinegar nnd finally vinegar is farther decomposed, and the vegetable matter, giving out an offensive smell, h said to purify. If the substance be not an expressed juice or liquid sleep, these several stages ol'fermen lation ensue with rapidity, liny bo going on at the same time, and aro sometimes so speedy in t heir course that no other action j but the punfactive fomentation can be delected. Animal bodies arc subject to the samo lows, and go through the same stages of fermcntntion, but the rapidity with which they run into putrefaction U even greater; still there are some cases, ns in that of milk where tho vinious stage can bo occasionally, and the acetic distinct ly ubscrved. Thus a vinious liquor is pre pared in some countries from milk, and the' sour tnste which appears iu it when kept arise, from the presence of vinegar. In the several stages of fermentation, parts of the vegetable assume the form of gas or vapor and are given out to tho oir. 1 he ga.es whicit have been detected, arc carbonic acid, n gaseous compound of car bon and livdrooeu, and in some instances 1 ammonia. The vapor is tnai water, 01 which the process is attended. If exposed to rain, soluble salts with earthly and alka line bases arc washed Irnm the mass. Fi nally a mass nf earthly consistctico olono remains, which on examination is found to be made up of catths, insoluble sails and carbon being in fact, idontical Willi vegeta ble mould. We may hence infer that the following elements exist in vegetable bodies : 1. Oxygen, developed in carbonic ncid water. 2. Hydrogen is in tho water and carbu rets or hydrogen. 3. Carbon. 1. Earths. 5. Alkalis. G. Nitrogen, occasionally dcvcloncd in the form of ammonia. 7. Acids, remaining in the insoluble, or wnhed away in tho soluble salts. J'he chemical examination of vccetnblc bodies ought of course leod to similar re sults. Tins examination has been conduc ted in three different ways. l. with the view of discovering tho na ture of the compounds called vegetable principles, winch exist, ready formed in plants. 2. For the purpose of discovering the chemical elements contained in these prin ciples. iiy the destructive action of heat, un der which some of the elements arc wholly separated, and others enter into new com binations. In tho 1st of these methods there have been detected: 1. Certain peculiar acids of which we may cite, (1) Acetic acid, which, mixed with wa ter, forms common vinegar ; t'-'i Mine acid, which is ound tn the lemon and orange. (3) Malic acid which exists in the apple. (J) lartanc acid in the juice of the grape. (5) Oxalic acid in tho wild sorrel- II. Certain substances of alkaline char nctcr, found principally in the medicinal plains, to winch they give their peculiar virtues. Gum, rosin, oils, sugar, starch, and two substnnces approaching to animal matter in their characters, namely, albumen and gluten; the tenner ot these has a resem bianco to the white of eggs, the latter to animai jeny or glue. Many other principles nre separated bv the same method in different plants, but need not be enumerated by us. The basis of this method consists in act ing upon vegetables hv water, ether, or rectified spirits (alcohol) and the principles auovo enumerated are cither simply, or in me unto ol combination in which thev ex i-t in plants, soluble in at least one of the liquids we have named. In nil cases some insoluble matter is left and this is known by tho name of the woody lib re. When these principles are treated in tho scsnnd method, oxygen, hydrogen, and carbon, are the uniform results, but in dif ferent proportion in the different cases nitrogen is also detected in some of them as, lor instance in the alkaline principle: in giutcn. i ins inetnod docs not appear to be adequate to determine whether earth or alkalis are or are not parts of these ve gctable principles. From tho very remark able fact, that some of those substances which nre very dissimilar to each other yield exactly the same proportions of oxv gen, hydrogen, and carbon, wo may fairly conclude by chemical analogy, that one or tho other, or perhaps both, contain some substances which have escaped the nnnlv sis. As an instance we may cite starch and sugar, whose characters are so dissim tlar that no danger can exist of mistaking the one for the other ; and vet their analy sis by the second method gives identical results. The third method may bo understood by comparing u wiui me process used in inn king charcoal. If this be so far altered that the heat employed shall not arise from the combustion of a part of the substance to bo examined, but from one merely used as lucl, and it tne matters winch escape in smoke arc condensed and collected, we shall have ttiat employed occasionally on a large scale by npcrative chemists. In this way charcoal will be as usual obtained in the solid form. The condcnsiblc products will bo water, tar, turpentine, or rosin ; and the acid which gives the character to vin egar, but which in the present case, in un ion with the tar and water, is called pyrol igouous acid. If the charcoal bo burnt in a current of air, all its carbon is converted, by union with the oxygen of the atmosphere, into carbonac acid, leaving a residue familiarly known as ashes. The ashes arc made up partly of soluble and partly of insoluble matter. The soluble matter is separated by the familiar process of making ley, and the ley, if evaporated leaven the substnnce so well known ns potash. Potash h principally composed of carbo nate ufpotassa, but contains, besides silica rendered soluble by the alkali, sulphate and muriate of potassa, and a peculiar acid known by the name ofulintc, which is a compound of carbon, hydrogen, and oxy gen. The insoluble part is made up of car. boiiato of lime, sulphate nnd sometimes phosphate of lime, silica. The carbonato of lime lias probably in no case existed in tho living plant, but arises from the destruction by heat of tho peculiar acid of ttic plant ; as, for instance, the citric, tho oxalic, or tho tartaric ; all of which arc by fire converted into caihonic acid. The quantity of ashes is extremely vari ous, a, is their proportion of the several soluble and insoluble substances, we have mentioned. Thus the ashes of the stalk of Indian corn yields 12 1-2 per cent, of ashes, while the sou woods do not lurnisii more than tiro parts in a thousand. The proportion ol the sulphate anil phosphate oil lime is even inuro various. I bus, in some cases the presence uf the sulphate hardly perceptible, while of the nshesof clover it forms a large proportion of the whole weight. Phosphate of lime is found in tho prnpnrtion of 15 per cent, in tho grain of wheat. Water is not only one of the principal component pnrtsof nil plants, but is nlso tho sole vehicle of thefr nutriment. At each extremity of the Email fibres into which the roots of plants are divided, is an open- ng through which that fluid enters: nnd it appears that , except in the cac of n plant having lost its vigour by continued drought, it is only through this channel that water can enter. By a powerful action inherent iu living vegetables, water, which with all the matters it is cpable of holding in solu tion, becomes the sap, is raised to tho highest parts of the plants, and forced to their most distant cxtreineties. It hnn been acertaincd that plnnl9 do not possets the poycr of rejecting even those substan ces which aro most noxious to t hern; it is therefore probable that the character of the fluid admitted is the same in all tha plants which grow upon the samo soil. Whether it undergoes any change in tho root docs not appear certain, but it has re cently been maintained that every descrip tion ot plant throws oil by the surtace ot itsv roots such matter as, if retained, would bo injurious; but this opinion docs appear to bo well established. The sap, when carried up to tho leave, undergoes an important change principally owing to the action of solar light. When exposed tn light, the leaves of plants give nut oxygen in considerable quantities.--This proceeds from a decomposition of tho water and carbonic acid, the remaining el ements of which two substances and a por tion of their oxvgen enter into new combi nations. These combinations have differ cnt characters in different vegetables, but are most familiarly known in the shape of gum and rosin. These still contain tho earthy and saiino matter carried up b'y tho sap, and after they are formed return down wards towards the roots. In their descent they deposite the several parts which minis, ter to the growth of tho plant the leaves, the bark, nnd the woody fibre. They also appear to bo forced wiih powerful energy into the flower and tho growing fruit, and in these a still more important action is carried forward, by which the reproduction of the species is insured. The matters which the water that enters by the root may hold in solution, nre eit It er derived from the atmosphere or from the soil. It, its passage through I ho air it will carry with it a considerable portion of carbonic acid, and all tho sulphuretted hy drogen it meets with. It will also take up a small quantity of oxygen, and of carbur ctted hydrogen, and a still less quantity of nitrogen. From the soil it will take all tho more soluble salts, small quantities of sul phate of lime, provided they bo present, and silica. So also if the soil contains animal matter, or vegetables of which nitrogen forms a part, the ammoina generated by their decomposition will likewise be dissol ved by tho water. In like manner tho car bonic acid, which has nriscn from the de conipo-itinn of vegctnble or animal matter and has not yet escaped, and the soluble, compounds of carbon, oxygen, and hydro-, gen, which arc generated by tho same pro cess, will have been taken up, and carried by the water into the root of the plant. It will thus appear that, contrary to the opin ion of Mr. Puvis, tho atmosphere furnishes but hltlo of the fixed element.? of plants;, with the exception of sulphur and carbon; and that even if the growth of plants were to depend wholly upon the carbon obtained in the form ofcarbonic ncid Trom the at mosphere. their growth must be slow and feeble. It will also appear, that if lime do not exist in the soil but few plants can find nourishment; and that for the ripening of the seeds ol grain phosphorus must be fur nished nlso. The latter substance may bo absorbed in small quantities from the plios phorcttcd hydrogen, which is occasionally present in the atmosphere; but a more cer tain supply ought to besought in putrescent manure, nnd particulary in that of animal origin. The uses of limo in ngriculture, as will appeir from thu foregoing remarks nnd tho reasoning of the essay, are ns follows ; 1. When a soil contains inert animal or vegetable matter, their decomposition may be promoted, and it may be rendered fit for the food of plants, by the addition of costic 1 1 me. 2 If tho soil contain acid that may bo neutralized either by costic or cnrbonatd lime, and besides, tho organic, matter whoso decomposition may have been prevented by the acid, will bo permitted to putrify. 3 Soils containing too much silica, or in other words tlnwo winch aro sandy, are made more retentive of moisture by tho addition of lime or its carbonate. 1. Clays may bo made less retentive of moisture and more friable by tho samo meaii3. 5. The gases which escape when vege table or animal matter purify, are reta'uwd in the soil by means of lime or its carbon ate; and thin n given quantity of manuro or the original vegetable matlcrof tho soil, will retain its efficacy no longer. By a recent discovery it has nlso been ascertain ed that the decomposition of plants yields a peculiar acid, called the liumtc, which forms with lime a salt sparingly soluble in water. The generation of this salt also serves to render tho nutriment contained in the soil morn lasting. C, Lime and its compounds arc absolute, ly necessary, us constituent parti, to tho growth of many plants. Tho sulphate a essential lo the' growth of clover, nnd tho phosphate to thnt of wheat. Hence tho efficacy of plaster of Paris, and crcslied bones ns manures. 7. If lime or its sulphate bo employed as the mean" of raising green crops, which have but small exhausting powers, thofor tilhty nf n soil may be maintained by ploughing them in, or increased by. using them to feed cattle whosalnauure is applied to the ground.