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oy ba. ae hi). Sige asl | THE FARMERS REGISTER: NEW SERIES. a en at EDITED BY THOMAS §, PLEASANTS.”
Published Monthly, at Five Dollars a year, in advance.
Vol. 1. @ Januarn,
PETERSBURG, VA.
PUBLISHED BY PLEASANTS AND STABLER.
LAURENS WALLAZZ, PRINTER.
1843.
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: oe a i be RB ng ‘s tied 3 ay : ce Baek x : Ee, : € - tee a | hie : ? | ee Weis ay iy i "ea ‘ k . : ae took ay — THRIFARNERS? RRCISTER, Is isoued in monthly . sabers (of 64 super royal octavo pages, )‘at five devars pcr annum, payable in os j advance. The premix copy, however. will a3 ° TERMS OF ADVERTISING. a. ¥ formerly be senttto say subscriber who may desire | For wequare,” or 20 lines,) 2 month, $1 oe it, of to the addrese $5 — individual ; Bow no | r $5°the year rémi (tance less than $5 can be received, and in the | ret CARE « of preminia Coples, payments must inv ariab)y i Bes LAURENS WALLAZZ, se toade in advance, at the time of ordering th: : anuery 1, 1843. Petersburg. wor. ? —
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tion. 212594 Jan. 1, 1848. LAURENS WALLAZZ.
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Should the plan meet with sufficient encouragement, the subscriber proposes to issue a super-royal weekly newspaper, to be called “The Pe- tersburg Gazette.” intirely free from party prejudice and sectarian bias, its columns will be devoted to Foreign and Domestic News, Com- mercial, Litera and Scientific Intelligence, &c.
From every available point of the wide and abundant field which pre- sents itself, the * Gazette” will collect such matter as wi!] best combine entertainment with instruetion. Among other interesting topics, a pro- minent one will be the illustration of the civil and natural. history of our native state, its soil, climate, scenery, productions, and resources ; the legends and traditions of the past; sketches of distinguished cha- racters, ac,
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THE FARMERS’ REGISTER.
JANUARY 31, 1843.
a
TO THE PUBLIC.
In assuming the conduct of the Farmers’ Register, | am fully sensible of the disadvan- tages of succeeding to a position which has been so ably occupied for ten years by the dis- tinguished individual who is about to withdraw from it. His Jabors in the cause of agriculture constitute a memorable era in its annals, In the tide-water region of the southern country his efforts and perseverance have brought to light hidden but wonderful resources; and his name will aiways be identified with them. For these and other services he is pre-eminent- ly entitled to the character of a public bene- factor.
To these claims upon public consideration I have not the slightest pretension to offer. It is believed, however, that the wants of the south will fully justify the continuance of such an organ as the Farmers’ Register, whose pages afford ample space for the most free interchange between members of the agricul- tural community. The present time also is full of interest in respect to the general pro- gress of agricultural knowledge. In every enlightened country the energies of some of the most powerful intellects are engaged in contributing to it. @hemistry and geology are no longer studied as isolated sciences ; their results illustrate the true principles of agriculture, and add a mighty stimulus to its advancement. From time to time, some com- prehensive mind,as of Davy or Liebig, collects, generalizes and applies the’ discoveries of others and its own, and establishes a great landmark to distinguish the progress that has been made in agricultural science, and to serve as a fresh starting point for the further ex- tension of its boundaries.
To convey information of this kind is now one of the chief duties of an agricultural journal. New combinations and affinities are daily revealed, and every farmer of intelligent and inquiring mind, who would keep pace with the improvements in his profession, must draw upon those public channels in which
the views and discoveries of the jearned are NEW SBRIES—Vo1L. 1.—]1
-
embodied and transmitted for the benefit of the many.
In few other works of the kind, perhaps, 1s there so much space for the publication of interesting matter as in the Farmers’ Register. Whatever is most valuable in the British agri- cultural periodicals, as well as our own, will as formerly continue to be republished. In connexion therewith, and also of the highest importance, will be the duty of engaging able and efficient contributors; the collection of useful facts; description of improved pratices and modes of farming, of the most approved systems of rotation, valuable inventions, &c. To these purposes, and with a single eye to the promotion of the interests of agriculture, horticulture and the rural arts, shall the work be devoted, with whatever of talent or indus- try the conductor may possess,
I venture then to express the hope that the friends and patrons of the Farmers’ Register, while under the direction of my predecessor, will not now withhold their support, but will continue both as subscribers and contributors to its columns. And to the agricultural public at large I submit my claim ‘for such general amount and proportion of patronage as the work, compared with cotemporary journals of a kindred character, may be thought to merit. ‘There are doubtless few practical cultivators to whom the price of a publication of this kind is not repaid several fold by the informa- tion derived from its pages.
Experience having shown that the recent terms of the Farmers’ Register, by which pre- mium copies were granted on certain con- ditions, were attended with some confusion and loss, instead of profit to the publisher, and a large portion of the subscribers having moreover never availed themselves of those conditions, they will be so far altered in future as to place the value of the publication at $5 the single copy, per annum, payable in ad-
vance,
The new series will be published in the saine form, of 64 pages monthly, and on paper of the same size and quality; but will be printed with new and handsome type. The
I
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m AY 2 33
2 THE FARMERS’ REGISTER.
first number will be issued on the 31st of January, 1843, and will be forwarded to all present subscribers who do not previously direct a discontinuance. Tuomas S. PLeasants. Petersburg Va.. November 28, 1842.
(FOR THE FARMERS’ REGISTER. ) INQUIRIES INTO VEGETATION. BY WILLIAM L. WIGHT.
The attention which is now being directed to the union of the science with the practice of agriculture will constitute a striking feature in the history of its improvement. The phe- nomena of nature, being offered to our obser- vation apparently without order, must be ar- ranged and connected by a general principle, before we can arrive at any thing like certainty of knowledge. The process of vegetation is a series of phenomena, linked together by a ge- neral law. Science is nothing more than a record of its particular phenomena, traced to others still more comprehensive, until we ar- rive at the connecting link which binds them into one harmonious whole. “ All the philoso- phy which has been reared by the labor of successive ages is the philosophy of facts re- duced to general laws, or brought under a ge- neral description, from observed points of re- semblance.” Many of the facts connected with the growth and nourishment of plants have already been brought to light by the genius and industry of our predecessors ; but much still remains to be done, and it is for us of the present day to supply the deficiency as far as we can, by contributing such facts as have escaped observation, and “ concentrating upon unknown phenomena the light reflected from those that are known.” In the hope of contributing something towards increasing our knowledge of this deeply interesting subject, the following inquiry will be opened with the leading facts of the science. These, together with other facts to be presented, and which also lie within the field of observation and ex- periment, will form the basis of farther con- clusions.
When seed is deposited in the soil, under favorable circumstances of moisture, heat, and air, the following chemical changes have been ascertained to ensue. A portion of the oxy- gen gas of the atmosphere disappears, and an equal volume of carbonic acid is evolved.* The first indication of this change is the ap- pearance of the part of the germ called the plumula, which alwavs ascends to form the stem and leaves ; while the other part, the ra- dicle, always descends to constitute the root. As soon as the first leaf has unfolded itself, an action directly the reverse of the one just mentioned takes place. Carbonic acid is now resolved into its original elements—one of them, oxygen, returned back to the atmo-
* Saussure.
here, while the other, carbon, is retained for ie nutritive purposes of the plant. And this action goes on uninterruptedly day and night, until the whole of the nourishment contained in the cotyledons or seed lobes has been con- sumed. This fact, which seems hitherto to have escaped notice, may be proved by the fol- lowing simple experiment. Let a seed resting upon moistened cotton be allowed fully to de- velope its first leaf. If this leaf be now intro- duced under a receiver, and supplied with ecar- bonic acid, it will be found to decompose this gas, and to evolve an equal volume of oxygen during the night as well asthe day. If the other seminal leaves, as they are successively unfolded, be treated in like manner, the same process will be observed to continue, by night as well as by day, until nothing but the enve- loping capsule of the germ remains. It is suf- ficiently evident from this experiment that the office of the seed lobes is not only to furnish carbonic acid, but to assimilate its carbon, until the organs of plants are so far developed as to effect the same object. When the food treasured up in the seeds is exhausted, the further growth and nourishment of plants is maintained through the ageney of exterior in- fluences. These are the soil, the atmosphere, and solar light. The soil is composed of silica, or sand, alumina, or clay, lime, and organic, or animal and vegetable, in variable propor- tions.
The atmosphere consists essentially of two gases, oxygen and nitrogen; but it contains also small proportions of aqueous vapor and carbonic acid. Light, when resolved into its constituent parts, was found by Sir Isaac Newton to be composed of seven different co- lored rays, violet, indigo, blue, green, yellow, orange and red.
The organs of plants being so far advanced as to act and to be reacted upon by these three exterior influences, we find that immediate re- course is had to a division of labor, to an eco- nomy of means, suited to the simple structure of the plant. Thus the leaves no longer de- compose carbonic acid at night, but enter upon their especial office, the absorption of oxygen gas from the atmosphere. During the day, carbonic acid is taken up by the roots, and transmitted to the leaves, when it is decom- posed through the agency of light. When this decomposition is effected with proper activity, plants uniformly exhibit to our view the green tint in all its beautiful varieties. If, however, this chemical change takes place either too slowly, or not at all, as is the case when the influence of light is diminished or withdrawn, the colors of plants become fainter and fainter, until they wholly disappear. For the disco- very that oxygen gas was given off from the leaves of plants during the day, one of the most beautiful in natural philosophy, science is indebted to Dr. Priestly ; and to Ingenhous, it is believed, for the first observation that light was essential to the process. So far, then, as the chemical changes which take place in plants fall within the reach of inquiry, the ultimate object appears to be the decomposi- tion of carbonic acid, and the assimilation of its carbon, in the completion of which process
8 t
THE FARMERS’ REGISTER.
the influence of light is essential. The key- stone, therefore, of an inquiry of this kind, is the knowledge of the circumstances. which diminish this influence, and of the means of increasing it. This knowledge can only be obtained by a diligent observation of the facts and analogies of nature, and by experiment. Nature speaks through her phenomena, and experiment is the mode of interpretation. Thus, in casting our view over almost any field of growing plants, we shall generally ob- serve surfaces, of greater or less extent, where the natural green is tinted off, into shades in- termediate between green and yellow. On in- specting these spots, we find that the cause, and only cause of difference, is the degree of moisture. Hence it appears that water, when habitually too abundant, is one of those cir- cumstances, and a very general one too, whose tendency is to diminish the chemical agency of light. ‘The first observation that led me to attach particular interest to this fact was the striking contrast in the color of two portions of a wheat field, the whole of which had been sown with the same variety of seed. One portion was immediately below a canal, in consequence of which the subsoil was kept constantly wet, by the oozing of its waters ; the other was adjacent to, and parallel with it, a ditch only intervening. In the spring, and especially after rains of some duration, the co- lor of the wheat on the portion next the canal approached very nearly ‘the orange tint. As the season, advanced and the surface became drier to a greater depth, this tint melted insen- sibly into the shades intermediate between green and yellow; but at no period of its growth did it attain the rich and pure green exhibited by the wheat beyond the drain. On farther observation and inquiry, this effect of water was ascertained to be a universal fact, as regards the nutritive or cultivated families of plants, and is familiar to every observant cultivator of the soil.* It is equally well known that the productiveness of plants growing in soils containing water in excessive — as a constituent part, is generally ess than that of those growing on higher and drier situations. Indeed, I believe it is gene- rally conceded that lands moderately undulat- ing, though they will not vie with the plains in point of the luxuriance, yet exceed them in the quality and value of their products. We all know how much the product of grain is diminished, even on uplands, when the seasons are unusually wet. Again, it is a matter of common observation and experience, that the atmosphere incumbent over wet soils is the source of all those affections comprehended under the generic term, “bilious.” These are all facts, which have been verified by nume-
* Whilst these observations are correct as regards the nutritive or cultivated families of plants, the converse holds true in respect of those of the aqua- tic species. These are the natural inhabitants of wet soils, and are greenest where there is the greatest excess of water; that is to say, the nutri- tive and aquatic species of plants affect opposite states of moisture. Hence both become pale under the same degree—a deficiency in the one case act- ing as an excess in the other.
3
rous observations and extensive experience.
If we now question nature still farther, by carefully taking up plants growing under the different cireumstances which have been de- scribed, placing them under a receiver, and supplying them with carbonic acid, the re- sponse will be, that those exhibiting their na- tural green decompose double the quantity of this gas, or impure air, and give off double the quantity of oxygen, or pure air, compared with those of a fainter tint. The same an- swer will be given if single leaves be separated
from their stems, placed in vessels of water,
and exposed to the direct rays of the sun. More bubbles will be seen to collect on the green than on the pale leaves, and these bub- bles have been proved to consist of oxygen gas. When plants of the aquatic species are submitted to experiment, they are found to give off more oxygen than the nutritive plants of dry soils.* ‘These trials have been repeat- edly made for many seasons, and the results have generally been accordant. ‘They are moreover perfectly consistent with the well- known and long established fact, that it is only in the green substance that the decomposition of carbonic acid oceurs with compensating activity. It appears, then, by following the path of observation and experiment, we ar- rive at the important conclusion, that the pro- ductive powers of plants, and the healthful- ness of the air we breathe, are connected in the relation of cause and effect, with that par- ticular constitution of plants which disposes them to reflect one ray of a pencil of light, the green, rather than another. But perhaps a more striking and convincing illustration of the views here attempted to be sustained is derived from the effects of lime when applied . to the soil. Few now are disposed to question the general fact, that lime is signally effica- cious in promoting the fertility of the soil. That it is inoperative, and even injurious, under particular circumstances, is likewise true; but this seeming contradiction occurs only when artificially applied; and hence should be ascribed to our ignorance of its pre- cise mode of action, and consequently of the proper state in which it should be used. But it appears also, from the observations of Mr. Ruffin, in his valuable Essay on Calcareous Manures, 2 work which will secure for its
author the enviable title of a benefactor to
mittent, or ague, and fevers prevail.
agriculture, and to mankind, that the use of lime has greatly diminished, and, in many in- stances, entirely suspended, the; regular an- nual visitations of the ordinary autumnal dis- eases. ‘These observations of Mr. Ruffin are corroborated by those of M. Puvis, who ob- serves, “that amongst all the countries to which line has carried and established fertility, there is not cited a single one where inter- The tes- timony of Sir John Sinclair to the same point is equally decided. He affirms it as an estab-
* This result, connected with the circumstance that plants of both species become pale under the same degiee of moisture, affords a satisfactory ex- planation of the curious but well known fact, that the bodies of marshes are healthy, whilst their bor- ders are the reverse.
%
4 THE FARMERS’ REGISTER.
lished fact, that a soil full of caleareous mat- ters never produces an unwholesome atmo- sphere. based not upon any preconceived opinions,
In view of evidence of this kind, | necting this power with the other well known
but upon the observation and experience of |
practical and enlightened men, it became a question of deep interest to determine what was the peculiar influence of lime in the pro- cess of vegetation; and for this purpose the following experiments were instituted. Seeds
placed first in glasses of water, and thus al- lowed to germinate. When two or more plants had put forth five roots, which is their complement, or an equal number, taking es- pecial care that those experimented with should have an equal number of roots, this being the test of their being equally healthy,
them to vessels of pure rain water, the other half to vessels of rain water in which a small portion of the hydrate of lime had been dis- solved.
As soon as the first leaf had attained suf- ficient length, they were introduced under separate receivers, and supplied with carbonic acid, It was soon apparent, however, that the plants growing in the pure rain water threw off more oxygen than the others, though the difference was slight. The experiment was repeated with the other leaves, as they were successively unfolded, but with no_ better success,
The carbonate of lime, or lime in the state itis found as a natural production, was now substituted for the hydrate. Selecting the thin pellicle which collects upon lime water, and reducing it toa fine powder, as much was pre- viously dissolved in the rain water in which half of the plants were to grow as could be, by brisk agitation for a few minutes in a closed bottle. ‘The plants to be experimented with be- ing always transferred from the glasses as soon as it was perceived that they had an equal number of roots. Previous to the period at which plants become dependent upon exterior
influences, the effeet of the carbonate of lime | is derived wholly from the decomposition of
was rather to retard than to quicken the de- composing process ; but generally, by the time the second leat had fully unfolded itself, and always in the case of the third, the greater re- sistance offered to the touch, and the deeper and more polished tint of green, inspired anti- cipations of a successful result. When intro- duced under the receivers, and supplied with carbonic acid, these anticipations were more than fully realized—the plants growing in rain water in which carbonate of lime had been previously dissolved, giving off two, three, and sometimes four volumes of oxygen to one disengaged by those growing in pure ‘rain wa- ter; and for every volume of oxygen emitted, an equal quantity of carbonic acid disappeared from the jar containing it. These experiments were frequently and carefully repeated with the other plants cultivated in this latitude, un- til it seemed to be fully ascertained that the influence of the carbonate of lime in the pro- cess of vegetable nutrition consists in increas- ing the action of plants upon the light—in so modifying their constitution as to dispose them
to reflect, under the ordinary defects of climate and season, their natural green; and, by con-
events in the series, viz., the more active de- composition of carbonic acid, whereby more carbon, the basis of vegetable matter, is assi- milated, and more oxygen returned to the at- mosphere, we obtain, as is conceived, a con- sistent explanation of the action of lime, both
_in the promotion of the fertility of the soil, of wheat, resting upon moistened cotton, were —
and in the restoration of the air to its purity.*
Thus it appears that the chemical changes
which take place in the leaves of plants, and upon which their health and vigor depend, as well as the purity of the incumbent atmo- sphere, are effected through the jomt agency of a particular ray of solar light and an alka-
line principle, forming an essential element in they were immediately transferred, half of |
the constitution of the plant, and disposing it to reflect this particular ray. It appears, more- over, to be equally essential that the attractive power of this principle should be so delicately balanced, so nicely adjusted, as to offer no op- posing force to the absorbing offices of the roots and leaves, or to the decomposing agency of the solar beam. A substance endowed with this nicely balanced equipoise of affinities, na- ture provides in the green matter attached to the stems and leaves of plants; and, however well suited this wonderful provision may be to excite the liveliest emotions of gratitude, love and praise, yet it should be borne in mind, that this is but one of the countless instances of beneficent adjustment inscribed upon the pages of this beautiful volume, to direct our thoughts habitually to the Source of all wis- dom, and power, and goodness.
A question here of deep interest arises: What is this green substance which is so nearly con- nected with our health, and with the fertility and beauty of our fields! Let us, as humble disciples of nature, search into this beautiful mystery, and see what response will be given to our interrogatories. 'The experiments of Sennibier have clearly proved, that the oxygen emitted by the leaves of plants during the day
carbonic acid—this carbonic acid being derived from the atmosphere, and from the soil formed by the union of the oxygen of the atmosphere with its humus.
To what purpose then, in the process of ve- getable nutrition, it may be asked, is the oxy-
*It is here proper to state that the atmosphere has been analyzed, and the proportion of oxygen
_ found to be the same in all regions and at all alti-
| tudes.
But that there must be some imperfection in the mode of analysis, arising from the small quan- tity of air submitted to test, or some other cause, is evinced by the following circumstances: First, that growing plants are known to be one source of com- nensation for the oxygen consumed by respiration, by combustion, and other natural operations; se- condly, that this oxygen is derived from the decom- position of carbonic acid ; thirdly, that it is only in the green substance that this process is conducted with sufficient activity to make full compensation ; and, fourthly, that the tendency of water, when con- stantly too abundant in the soil, is to counteract the formation of this green substance in plants of the
nutritive species, or those cultivated for the use of man.
la i “ee len
THE FARMERS’ REGISTER. 5D
gen absorbed by the leaves nt night subser-
the other elements of the plant, because the vient! To answer this question let us recur
absorption of this gas is the especial office of
to the facts bearing on this point. Thus we have seen that plants, in the earlier stages of their developement, decompose carbonic acid uninterruptedly, day and night, in virtue of a power possessed by the seed, of not only fur- nishing carbonic acid, but also the means of its decomposition. In the mean time, observe, provision is being made for the aecomplish- ment of both these purposes, by the extension
the atmosphere. As soon as these organs are sufficiently developed to draw food from extra- neous sources, and to adapt it to their wants,
means is resorted to, suited to the simple structure of the plant—the decomposition of carbonic acid at night is discontinued, and the absorption of oxygen by the leaves commences.
The very fact, then, that the especial office of the leaves is to absorb oxygen, and that the decomposition of carbonic acid ceases at night the instant that they enter upon this office,
would seem to evince that there is an intimate connexion between the two processes, and that the one at night is preparatory to that of the day. The nature of this connexion may be inferred from the fact that plants are of a brighter green in the morning than in the evening, thus exhibiting a striking analogy be- tween the functions of the leaves of plants and of the lungs of animals. In the one case the change of the blood from a darker to a brighter tint, from its union with oxygen in the lungs,
is essential to the healthy activity of all the functions of the system. In like manner, the conversion of the dark green of plants, arising from the accumulation of carbon, to a brighter tint, by the absorption of oxygen by the leaves at night, is alike esse1.tial to the activity of the decomposition of carbonic acid by day.
The same difference of color is observable between leaves which are growing, or which continue to absorb oxygen at night, and those whose functions of this kind, having ceased with their perfect developement, are directed to other purposes. The former exhibit a bright green strikingly contrasted with the dark green of the latter. “This difference is conspicuous in all plants, but particularly so in the carrot.
Again—the peculiar influence of lime in imparting a healthier green to plants, com-
mencing, too, as it does, simultaneously with |
the absorption of oxygen by the leaves at | green rather than any other color. We cannot
night, would seem to justify the inference, not only that the formation of the green substance constitutes the nocturnal functions of plants, but that the substance thus formed was alka- line in its character. And this opinion re- ceives additional weight from the fact that oxygen is known to enter as an essential ele- ment into all the vegetable alkalies. Finally, the leaves are the organs in which the decom- position of carbonic “acid takes place, but not the agent by which it is effected. That agent is light; but, to render it effective, there must be an aptitude on the part of the leaves to re- flect the green or chemical ray. Now this aptitude can arise only from an alkaline com- pound formed by the union of oxygen with
Thus,
the leaves, and one of the characters of an al- kali is to change vegetable blues to a green. if the carbonic acid absorbed during the day is not decomposed, the tendency of the plant is to reflect one of the colors between the green and the red end of the spectrum. When the night arrives, and oxygen is again absorbed, this tendency is still farther increas-
| ed. If, however, the carbonic acid is decom-
of its roots into the soil, and of its leaves into | posed, the tendency is to reflect one of the co-
lors towards the violet end or the blue ; under these circumstances the green is renewed by
| the absorption of oxygen.* Reasoning then a division of labor ensues—an economy of |
from phenomena, and deducing causes from effects, it does appear that the office which oxygen fulfils in the process of vegetation is the renewal at night of the pure green, which is modified during the day by the assimilation of carbon. According to this view, the pro- cess of respiration in plants is performed at night, that of digestion by day.
From the facts which have now been pre- sented, we collect that the food of plants, con- sisting mainly, as far as ascertained, of water holding carbonic acid in solution, is derived in part by their roots from the soil, and in part by their leaves from the atmosphere. It is, how- ever, a well ascertained law, that no food is adapted to the purposes of life until it has been resolved into its original elements. This decomposition, this conversion of food into nourishment, is effected in the leaves through the agency of light, and the activity of the process is governed, wé have seen, by the apti- tude of the plant to reflect one particular ray of this light—the green ray. But it is clear this aptitude must arise from a particular con- stitution of the reflecting body; and the view has been proposed, that this modification is effected at night by the elements of which the atmosphere is essentially composed—that such is the part which the atmosphere performs in the process of vegetation at night, a part equally essential with that it performs du- ring the day, but of a wholly different, and even opposite character. But whether this in- ference be correct or not, still it appears that the carbonate of lime, ashes, plaster, &c., have the power of imparting this constitution, and the knowledge of this fact is sufficient for all practical purposes. We cannot know why these substances dispose plants to reflect the
know why the reflection of this color deter- mines the more active decomposition of car- bonie acid. Neither can we know why the perfection of vegetation and the healthfulness of the air we breathe are constantly conjoined with the completion of this chemical change.
_ But observation and experience, the only true
sources of all knowledge of nature, appear to teach us that such is the relation, such the
*«*The substances capable of combining with oxygen afford one or other of the following products : 1, an acid ; 2, an alkali or earth; 3, an oxide. An acid is a body which reddens vegetable blue colors ;
while those that are alkaline change vegetable blues to a green.”
6
succession of events, and that these events are invariable in their concurrence.
Admitting now the accuracy of all the fore- going observations and experiments, the ar- rangements of matter connected with the growth and nutrition of plants will receive a consistent explanation on the electro-chemical theory of Sir Humphry Davy.* Thus it is conceived that, by the union of the oxygen and nitrogen gases of the atmosphere at night with the other elements of the plant, an apti- tude is given to reflect the purely green ray of solar light—or a similar disposition may be im- parted artificially by the application to the soil of the alkaline carbonates or salts of lime. On the return of day this function of the leaves ceases. The carbonic acid taken up by the roots is now transmitted to the leaves. By contact the electric equilibrium of these two substances, the acid and the alkali, is disturbed, but only for a moment. ‘The equilibrium is no sooner restored, than it is again disturbed by the influence of a surface of greater intensity than that by which they are held together, viz., the green or chemical ray of solar light. Hence the elements of the compound are dis- united, the oxygen disengaged, and the carbon retained for the nutritive purposes of the plant. Such are the phenomena exhibited by plants of the nutritive class on soils free from all su- perfluous moisture. On the contrary, when plants of this species are cultivated on soils containing water in excessive proportion as a constituent part, the same combinations occur, and the same decompositions ensue, but as they do not reflect the purely green or chemi-
‘al ray, or, in other words, are exposed to sur- faces of less intensity, their chemical char:es are effected with diminished activity; «and hence the difference in the value of their products and in the purity of the incumbent atmosphere under such circumstances,
According to the above view, the absorption of oxygen gas at night, which appears to be opposed to the purifying tendency of growing plants, is absolutely essential to the intended result; thus affording a beautiful instance of the mutual and essential dependence of two opposite adjustments. The fact, moreover, that plants assume a fainter tint than natural only under the influence of a disturbing force, rela- tively considered, reconciles another apparent inconsistency, with the harmony of all the other known operations of nature.
The practical rules deducible from the fore- going facts are—
Ist, That, as the growth and nourishment of plants appear to be alike de *pendent upon
the products of the decomposition of organic or |
animal and vegetable matters, and upon those inorganic substances which increase their ac- tion upon the light. We are thus admonished of the necessity, the absolute, indispe nsable ne- cessity, of periodically returning to the soil an amount of both these elements corresponding with that which was taken from it by cropping. If neither be returned, the soil must and will
* A very clear exposition of Sir Humphry Davy's theory maybe found in Professor Turner’s Elements of Chemistry, in the section on galvanism.
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THE FARMERS’ REGISTER.
deteriorate, because plants will thus be deprived of the means by which they live and grow. If one of these elements or vegetable matters alone be restored, the productive power of plants will not be developed to the extent of which they are susceptible; both are essential.
To the corruption of decayed plants the leaven of the salts must be added to give rise to forms of the highest beauty and usefulness. The superiority of animal and putrescent manures, as they are termed, over those of vegetable origin, is owing, it is conceived, solely to the alkaline salts which the former contain. But,
as in these the ammoniacal or volatile salts predominate, their effects are necessarily tran- sient, and hence the utility and wee of using those of a more fixed character, as lime and ashes. In the decision of the question as to the quantity of the alkalies to be applied to the soil, it has never been considered that their direct and indirect effect should be kept entire- ly distinct. In the former case this question, it would seem, ought to be determined by their solubility. It is well known that plants can take up nothing except in the form of solu- tion, and we have abundant evidence going to show that the effects of fifty or a hundred bushels of lime or ashes applied to an acre of land have been distinctly visible for an equal number of years. Hence it would appear that the quantity of rain which falls upon an acre of land annually is not adequate to dissolve more than a bushel of these substances. If more were dissolved plants would certainly take up a larger quantity, and the effects would necessarily be less permanent. If then this mode of reasoning be correct, a bushel of
_ lime, or ashes, or plaster, will be fully sufficient
for the attainment of their direct influence. To secure their indirect benefits in loosening the soil, and rendering it more permeable to
_ atmospheric influences, thus alleviating human
toil, a much larger quantity will be required.
Is the question here asked, whence is the magical influence of plaster compared with the other salts of lime, if they all act upon the same general principle? The answer seems to be, that it is referable to its greater power of increasing the action of bodies upon the light. ‘Thus the experiments of Sir Isaac Newton have shown that bodies of an unctu- ous or sulphureous nature have a greater relative refractive power than others, or than their densities would indicate. Plaster is a sulphate of lime, consisting of sulphur, oxygen and lime. May we not hence fairly infer that it is the subtle influence of