Lapas attēli
PDF
ePub

“Although we have long been practically familiar with the expansive effects of æriform fluids suddenly disengaged chemically from an apparently solid and inert substance like gunpowder, either in fire arms or the blasting of rocks, and with their elastic recoil when released from the pressure of condensation, as in the air-gın or the liquid gases of Dr. Farrady we were not prepared for so beautiful an instance of the application of this principle as the one Chevalier Claussen has given us in the splitting of vegetable fibres by conveying into its interstices the carbonic acid gas concealed in condensation and chemical alliance with soda, and then setting it free by the addition of acid, which breaks off that alliance by its own superior elective affinity for the alkali. The flax fibre, soaked in the solution of sub-carbonate of soda, was no sooner immersed in the vessel containing the acidulated water than its character became at once changed from that of a damp, rigid aggregation of flax to a light, expansive mass of cottony texture, increasing in size like leavening dough, or an expanding sponge. This change was no less striking when this converted mass, in its turn, was placed in the next vessel, which contained the hypo-chlorite of magnesia, and became at once bleached, attaining then the color, as it had just before received the texture, of cotton.

Some objections have been taken to this process by persons who appear to regard flax as a material which ought to be solely applied to the manufacture of linen or cambric, and think that any preparation of it which does not best adapt it to the manufacture of these fabrics is to be discountenanced. The attempt to substitute flax for cotton has even been stigmatized as a reductio ad absurdam by an extensive flax grower and manufacturer in Belgium, and who also expressed his opinion that any invention by which cotton could be transformed into flax would be justly entitled to the merit of a great discovery.

The objection is founded upon the supposition that the fibre is greatly reduced in strength by the process resorted to. When compared with fibre of an equal degree of fineness, prepared upon the most improved methods of steeping, the results have been decidedly in favor of the mode just described. When the fibres, however, are split, it is perfectly natural to suppose, inasmuch as "a part is less than the whole,” that the filaments into which they are split are not of the same strength as the fibres of which they originally formed a part. The strength of the fibre is reduced in proportion to the division of the parts which takes place, and is not impaired by the action of any of the chemnical ingredients employed. The strength of the fibre, when brought into a fit . state for the cotton-spinner, is not, therefore, to be compared with that required for the stronger and more durable linen yarns, but with that for which it is intended to be used as a substitute or auxiliary--namely, cotton or wool, with which it will bear the closest comparison.

Should the grower of flax not be disposed to undertake the complete preparation of his produce, and the existence of markets in his immediate neighborhood for the flax in the straw should render it unnecessary for him to reduce its bulk, the sale of the flax in that state would be attended with profit greater than can be obtained from any ordinary crops, as shown by the following statement made by Mr. Druce, of Ensham, in Oxfordshire, the piece of ground on which his flax was grown consisting

of a deep-red loam, in extent 5 acres, 2 rods, and 36 perches. His profits were as follow:

[merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

Sale of flax-seed, 204 bushels per acre, 1161 bushels, at 8s. 46
Sale of flax straw, 12 tons, 2 cwt., 2 qrs., at £3 per ton 36
Sale of chiff, at 5s. per acre

1

8. 10 7 8

d. 0 6 7

[ocr errors]

Total receipts

84

6

1

Thus leaving a net profit of £47 158. 9d.—being equal to L8 6s. 2d. per acre of land employed in this trial of flax cultivation.

It may not be improperly asked, why, if the cultivation of flax be so advantageous, it has not been more generally carried out in England ? The answer to such an inquiry may readily be found in the difficulties which have hitherto existed with respect to its preparation, and the uncertainty of the market for the produce when so prepared. Objections, founded on the character of the crop, and the comparatively high prices of grain, have, no doubt, had some influence in preventing the cultiva. tion of a plant which was considered to be highly exhaustive, and had not the advantage of a protective system. By a change in the com-, mercial policy of Great Britain, both flax and corn crops are placed upon the same footing; and the agriculturist, under these circumstances, will doubtless devote himself to the production of any article that promises an adequate return for his labor and capital.

The opinion that flax is an exceedingly exhaustive crop, is one that has long been entertained by the agriculturist; and the clauses which, in many cases, are introduced into the agreements and leases of farming tenants in Great Britain, forbidding the culture of flax, hemp, and woad, have, no doubt, tended to strengthen this opinion. It is quite certain that flax, in itself, like all other crops, is an exhaustive one. The farmer. does not refuse to grow wheat because it is exhaustive, as he knows that a great proportion of the crop is returned to the soil. There are two modes of testing the accuracy of opinion with respect to the inju.

rious effects of the flax cror-namely, by chemical analyses, and also by practical experience; the last of which is the most convincing to the grower.

Specimens of Woad.-E. Gilman, Twickenham.

sun

This plant was once cultivated to a great extent for blue dye extracted from it, but has been greatly superseded by indigo. It might still be cultivated to great advantage, as it improves the quality and color of indigo when mixed with it in a certaiņi proportion. The plants, when just about flowering, are mown with a scythe, washed in water,

and dried; after this they are ground into a paste, which, kept in heaps for about a fortnight, is then formed and pressed into solid balls. It is also occasionally sown as food for cattle, and has lately been recommended for this purpose, under the name of “pastel.” Its vigorous growth and hardy nature are in its favor; but it will only flourish in very rich soils.

MANURES.

Superphosphate of Lime and Bone Dust; prepared by A. Ramsey, 65

Mark Lane, London.
Manures for Corn, Hops, Turnips, and all other Crops; prepared by the

Inorganic Manure Company, Bów, London.
Peruvian Guano, Saltpctre, Nitrate of Soda, Prepared Night Soil.

Every substance which has been used to improve the natural soil, or to restore to it the fertility which is diminished by the crops annually carried away, has been included in the name of manure.

It is well known to all practical agriculturists that the texture of the soil, and the proportions of the earths of which it is composed, are the first and most important conditions of its productive powers. Where there is a good natural loam, which retains moisture without being overcharged with wet, and permits the influence of the atmosphere to pervade it, the crops cannot fail to be more certain and remunerating than in loose sand, or tenacious clays; but at the same time it is equally true, that the best texture of soil will not produce good crops for any length of time without the help of manure, to recruit the loss produced by vegetation.

The methods employed in the cultivation of land are different in every country; and when we inquire the cause of these differences, we receive the answer that they depend upon circumstances. No answer could show ignorance more plainly, since few have ever yet devoted themselves to ascertain what these circumstances are. Thus, also, when we inquire in what manner manure acts, we are answered that the excre. ments of men and animals are supposed to contain an incomprehensible something which assists in the nutrition of plants, and increases their size. This opinion is often embraced without even an attempt being made to discover the component parts of manure, or to become acquainted with its nature.

In addition to the general conditions, such as heat, light, moisture, and the component parts of the atmosphere, which are necessary for the growth of all plants, certain substances are found to exercise a peculiar

[ocr errors][ocr errors]

influence on the development of particular plants. These substances either are already contained in the soil, or are supplied to it in the form of substances known under the general name of manure.

But what does the soil contain, and what are the components of the substances used as manure? Until these points are determined, a rational system of agriculture cannot exist. The power and knowledge of the physiologist, agriculturist, and chemist must be united for the complete solution of these questions.

The general object of agriculture is to produce, in the most advantageous manner, certain qualities, or a maximum size, in certain parts or organs of particular plants. Now this object can be attained only by the application of those substances which we know to be indispensable to the development of these parts or organs, or by supplying the conditions necessary to the production of the qualities desired.

The rules of a rational system of agriculture should enable us, therefore, to give to each plant that which it requires for the attainment of the object in view

As the composition of soils forms an important feature in the profession of agriculture, it will be our duty to explain, as briefly as possible, some of those which have the most distinct characters from their con. nexions with different geological formations.

There are various modes of distinguishing soils without entering into a minute analysis of their component parts. The simplest and most natural is, to compare their texture, the size and form of the visible particles of which they are composed, and to trace the probable source of their original formation from the minerals which are found around or below them. The science of geology is of great utility in aiding us to compare different soils and ascertain their composition.

The soils which are immediately derived from those rocks, in which no traces of organic remains are to found, consist either of visible fragments of hard minerals, which are not affected by exposure to air or water, or of minuter particles of the same, of which the shape is not readily distinguished by the naked eye. When they are altogether composed of visible particles and stones, the water readily passes through them; and unless they are kept continually moist by a regular irrigation, without any stagnation of the water, they are absolutely incapable of sustaining vegetation.

It is seldom, however, that any gravel or sand does not contain some portion of earth or other matter, of which the particles become invisible when diffused through water, and to which we will here give the general name of impalpable substance. A certain portion of this finer part of the soil, and its due admixture with the coarser, especially where there is some regular gradation of size, and no stones of too large dimensions to obstruct the instruments of tillage, may be considered as essential to fertility.

The soils which have been formed from the disintegration and decomposition of the primitive rocks, such as granite, basalt, or limestone, and those which contain all these minerals minutely divided and intimately mixed, are always naturally fertile and soon enriched by cultivation. The hard particles of quartz maintain a certain porosity in the soil, which allows air and moisture to circulate, while the alumina prevents its too rapid evaporation. The silicate of potash is highly favorable to the vegetation of those plants which contain silica in their stems; in fact silica is pres. ent in the ashes of nearly all plants, having entered the plants by means of alkalies.

The primitive limestone, which is very hard, is yet gradually decom. posed by the action of air and water, being in a very small degree soluble in the latter. The water which flows through these rocks is soon saturated; but when it springs out and comes to the light, the carbonate of lime is deposited by the evaporation of the water; and if this meets with the clay which results from the decomposition of the slate, it forms a marl, which, naturally or artificially added to silicious sand, forms the basis of a very good soil, particularly well adapted to pasture.

The soils, which have evidently been formed from the rocks, which are supposed to be of secondary formation, are fertile according to the proportion of the earths of these rocks which they contain. It is of these chiefly that those loose, sandy soils are formed, of which the particles appear as distinct crystals, easily distinguishable with the aid of a lens, or even by the naked eye. Air and water have been the chief agents in the decomposition of those secondary rocks called sandstones, and agitation in water has washed from them the finer portions which have remained suspended. The immense sandy plains, which are for the most part barren, have probably once been the shores of the sea, from which the waves have washed all that portion which was impalpable and easily suspended in water, depositing this in the depths, which, by some convulsion in nature, may some time or other be raised above the level of the waters, and form hills or plains of clay.

Argillaceous earth exists, in some proportion, in almost every rock. Some of the hardest gems are chiefly composed of alumina. It has the property, when mixed with other substances, as silica or lime, of fusing into a stone of great hardness and insolubility. In this state, its effect on the soil is not to be distinguished from that of silica; and by burning common clay, or clay mixed with carbonate of lime, a sandy substance is produced, resembling burnt brick, which tends greatly to improve the texture of those clays which contain little or no sand in their composition. It must be remembered that the stiffest clays contain a large portion of silica in an impalpable state; but this, instead of correcting their impermeable and plastic nature, rather adds to it. It is only palpable sand, which, with clay, forms what is commonly called loam, and which, when the sand is in due proportion with a mixture of organic matter, forms the richest and most easily cultivated soils. Some of the rocks of secondary formation contain a considerable portion of alumina and lime; and when these earths meet with crystallized sand, a compound, or rather a mixture, is formed which has all the requisite qualities, as to texture, to produce the most fertile loams. The only deficiency is organic matter; but this is so readily accumulated wherever vegetation is established, or can be so easily added artificially, that these loams may be always looked upon as the most favorable soils for agricultural operations; and if a considerable depth of loam is found, which neither retains water too long nor allows it to percolate too rapidly, it may be looked upon as a soil eminently capable of the highest degree of cultivation. It is known that the aluminous minerals are the most widely diffused on the surface of the earth; and all fertile soils, or soils capable of culture, contain alumina as an invariable constituent. There must, therefore, be

« iepriekšējāTurpināt »