REMARKS UPON ITS CULTIVATION AND TREATMENT.
Of all the fibre-yielding plants known to botanical science there is not one so well calculated to meet the pressing requirements of the Paper-trade as "Bamboo," both as regards facility and economy of production, as well as the quality of the "Paper-Stock" which can be manufactured therefrom: grown under favourable conditions of climate and soil, there is no plant which will give so heavy a crop of available fibre to the acre, no plant which requires so little care for its cultivation and continuous production.
The rapidity of the growth of "Bamboo" is unequalled. At Gehzireh, the gardens of the Khedive of Egypt at Cairo, it has been known to grow nine inches in a single night. At Syon House, the Duke of Northumberland's, stems of "Bambusa Gigantea" have attained the height of 60 feet in 12 weeks; and I have made "Paper-Stock" from a stem of "Bambusa Vulgaris," sent me by Dr. Hooker, from the Royal Botanical Gardens at Kew, which, as measured by the gardener in the Palm-house, grew at the rate of three feet in a single week; at Chatsworth, the Duke of Devonshire's, this same variety (the "Bambusa Vulgaris") has attained the height of 40 feet in 40 days.
Throughout the East Indies the "Bamboo" flourishes, forming indeed in many districts impenetrable jungles. It grows abundantly also in the West Indies, in Central and South America, the Brazils, in Africa and Asia; in China especially, and in Japan, the plant is indigenous, and the natives cultivate it carefully, employing it for almost every article of convenience and luxury; in fact, wherever heat and moisture exist, some species of the "Bamboo" will be found, or may be readily cultivated.
Attempts have from time to time been made in England, and elsewhere, to obtain from the "Bamboo" "Half-stuff" or "Pulp" suitable for the manufacture of paper, and paper indeed has been made therefrom, but hitherto these attempts have neither industrially nor commercially attained successful results, and for the following reasons.
Hitherto the "Bamboo" has been collected and treated in a condition more or less of maturity, or without regard to its age; and when the plant has attained its full growth the woody fibre is extremely dense and indurated; when old, indeed, the exterior portion of the stem of many varieties of the plant becomes so hard and silicious that it will, like flint, strike fire with steel.
Owing to the presence of this large quantity of silica, and the extreme hardness of the stem when developed and matured, it has been found by all those who have hitherto experimentally treated "Bamboo" that the only possible means of converting it into Pulp for Paper-making, has been to subject it to long-continued boiling, or digesting, in very strong solutions of caustic alkali, at an elevated temperature—in other words, at or under a pressure of ten to eleven atmospheres (150 to 160 lb. pressure per square inch)—by which means a Pulp has certainly been produced, but at a great cost, and the danger and practical difficulties of working under such high pressure, have deterred further progress in this direction.
I have found that when the stems of "Bamboo," are cut down at an early stage of their growth, when the plant is full of sap, and before the cellulose or cellular tissue, and the lignine have become indurated, and silica deposited; while, in fact, so to speak, the plant may be termed a succulent vegetable, and before it has become converted into wood, that a very mild system of treatment in successive weak alkaline baths, at atmospheric pressure only, suffices to decompose and render soluble the mucilaginous and other extractive compounds combined naturally with the fibrous tissue of the plant, so that they may be readily eliminated, or separated therefrom, by subsequent washing, leaving the residuary fibres pure and free.
A comparative illustration of the transitional stage of growth above referred to, showing the conversion of succulent vegetable fibrous tissue, into harsh woody fibre, may be remarked with "Asparagus," the young and green stems of which, are used as a delicacy for the table, a few weeks further growth converting them into hard woody fibre, which no amount of boiling would, or could, render palatable; the "Asparagus," indeed, has its parallel in the "Bambusa Edulis," a variety of "Bamboo," the young stems of which are eaten and considered very nourishing.
The "Bamboo," being an endogenous plant, (that is to say, growing from inside) composed mainly of fibrous tissue, combined with the ordinary sappy and other extractive matter common to all vegetable growth, the stems do not require the elaborate preparatory manipulation which is necessary to separate the fibrous, from the extraneous and woody matter, which in exogenous plants (i. e. growing from, or on the outside) must be removed, as it is only the true fibre which is useable for Textile Manufactures.
Such plants known to commerce as "Flax," "Hemp," "Jute," "Rhea," &c. &c., after having become mature, and being dried, have to undergo a process of retting, or steeping, followed by scutching and heckling, in order to separate the ultimate fibres from the woody stem and bark to which, while in their normal condition, they are attached.
The cost therefore, of producing merchantable fibre from this class of plants is very considerable, and the produce or yield of fibre, to the plant cultivated, very small, that of "Flax" being computed at from 5 to 6 cwt., "Hemp" 7 cwt., and "Jute" 5 to 6 cwt. per acre, "Cotton" being much less; "Bamboo," as I will presently show, producing tons as compared with cwts. of the foregoing, and, be it noted, with far less cost for cultivation, and the subsequent preparation of the fibre.
The stems of the "Bamboo," cut young, as I propose to use them, contain from 60 to 75 per cent. of moisture; it will be obvious, therefore, that to ensure a regular and continuous supply, under economical conditions, to a central factory for the manufacture of "Paper-Stock," plantations would have to be formed contiguous thereto, as practised with "Sugar Cane," or in a similar manner to Osier beds, in England.
I have mentioned the latter, as in order to stimulate a rapid, aqueous, and sappy growth, as also to provide for the dry seasons common to hot countries, a system of irrigation would be necessary, such a system indeed being at present practised with the Sugar Cane, in Egypt, Spain, and elsewhere.
With plantations of "Sugar Cane," to which plant the "Bamboo" somewhat assimilates in character and growth, it is necessary, in order to ripen the canes and develop saccharine, to allow free ventilation to the growing plant, and thus the ground is not fully occupied; this would not be the case with "Bamboo," which should be planted and grown closely together to favour the stems shooting upwards, as practised with "Hemp" and "Flax," where fine staple of fibre is desired.
By following such a system, the stools or roots once established, a systematical and regular cropping, or cutting, would ensue, the stems being all cut down simultaneously, by sections or beds, in regular succession, numerous croppings annually would thus be obtained, and when necessary, fresh beds would be formed, the older growth being available for fuel for the manufactory.
The Sugar Cane from the time of planting, to cutting, takes from nine to twelve months to grow and mature; but even thus grown, the produce of canes (ready dressed for the mill) generally ranges from 30 to 35 tons to the acre, it sometimes exceeds 40 tons; allowing several crops or cuttings annually for the "Bamboo," it may fairly be assumed that at least this latter quantity would be obtained per acre.
Allowing 208 feet square to represent one acre; divided into twelve beds, each 96 × 26 feet, with twelve paths 96´ × 8´ 8´´ wide, and one intersecting road 208 × 16 feet wide, leaves a space for planting equal to 2496 feet, or 29,952 feet in the twelve beds; allowing the stems to be 2 feet apart, and say only 12 feet high, we have 7488 stems, which at 12 lb. each = 40 tons per acre.
The stem of the "Bambusa Vulgaris" before mentioned, grown in the Palm-house at Kew, was of an average size, 10 to 11 inches circumference, and weighed green 11/2 lb. per foot run; and although no doubt by denser growth, induced by frequent cropping, the stems even of the larger varieties of "Bamboo" would decrease in size, still an equal tonnage to the acre would be produced, with longer joints or internodes, and a finer staple of fibre.
The stems of the "Bamboo" (taken as dry) treated by my process, will yield 60 per cent. of unbleached Fibrous "Paper-Stock," baled up in merchantable condition; assuming therefore an annual cropping of 40 tons, green stems, which will lose 75 per cent. moisture in drying, we have 10 tons dry stems per acre; these at 60 per cent. yield, will give 6 tons per acre of "Paper-Stock," an enormous product as compared with any other fibrous material with which I am acquainted.
Allowing the plantation to be credited at the rate of 5s. per ton, for the green stems, delivered to the central factory, and 40 tons to be produced per acre, we have the sum of 10l. per acre to cover all charges; once, however, the plantation formed, but little cost in the way of cultivation need be incurred. The main outlay would be for rent, irrigation, and cutting, and carrying to the manufactory.
I may here remark that I propose where possible, to return to the Plantation, mixed with the water employed for irrigation, the mucilaginous and other extractive constituents, or matters, (amounting to 40 per cent.) abstracted from the stems during the process of manufacturing the "Paper-Stock," as Manure, thus maintaining fertilization to the growing plant.
Details of my System of Treating "Bamboo" for the Manufacture of Fibrous "Paper-Stock."
An essential point in my system for treating "Bamboo" to produce therefrom fibrous "Paper-Stock," consists in operating upon the stems of the plant when young, and preferably when fresh, as, and when, cut and collected.
Brought therefore to a central factory in this condition, the stems are passed through heavy crushing rolls, in order to split and flatten them, and at the same time crush, or smash, the knots, or nodes. The stems thus flattened, are then passed through a second series of rolls, which are channelled, or grooved, in order further to split, or partially divide them longitudinally into strips, or ribbons; these being cut transversely, into convenient lengths by a guillotine knife or shears, are delivered by a carrier, or automatic feeder, direct to the boiling pans, or elsewhere, as desired.
As the stems when fresh and green, contain from 60 to 75 per cent. of sappy and mucilaginous matter, much of this is expressed by the crushing, while at the same time the fibrous mass, being partially disintegrated, is thus more readily acted upon in the succeeding processes.
If desired, the crushed stems may be dried and stored; such drying, however, must be very carefully conducted and watched to avoid destructive fermentation.
I have in the preceding "Remarks" referred to "Flax," "Hemp," "Jute," and similar Fibres known to commerce, such fibres being imported into this country in their prepared condition, suitable for Textile purposes. They have, in fact, passed through a process of semi-manufacture, such process, as I have explained, being required to separate the ultimate fibres from the interior woody stem to which when growing they are attached; and it is obvious that it would not be (economically) possible to import any of these fibrous plants as grown or produced, owing to their enormous bulk in that condition.
Now although the stems of the "Bamboo," after cutting and crushing, may, as I have shown, be dried (and will when dried give a yield of 60 per cent. of fibre), still their bulk and extreme lightness would preclude importing them to this country in their raw condition, not merely from their heavy cost for carriage, but from their liability to damage from fermentation. For these economical considerations, therefore, I propose to reduce the "Bamboo" into "Fibrous-Stock" where grown or produced.
It may be well, before entering into details of the process, briefly to explain the ordinary system employed for preparing fibres, or fibrous materials, as also rags, for Paper-making. This consists in sorting, cutting, cleaning, and, if need be, roughly opening them, followed by boiling in alkaline leys, after which they are well washed until cleansed from impurities in what is technically termed the rag or breaker engine, during which operation they are disintegrated or reduced into "Half-stuff," or semi-pulp, this being subsequently bleached and converted into pulp and paper.
As the object of my process is to produce a fibrous or tow-like Stock, retaining as far as possible the normal or natural condition of the fibre, and not "Half-stuff" or "Pulp," my system of treatment differs materially from the foregoing, more especially in the boiling and washing processes.
Both of these processes I conduct in a battery, or series of vessels (16, 20, or more in number), such vessels being connected together by pipes, or channels, furnished with valves, or cocks, so that communication between the individual vessels may be maintained, disconnected, and regulated as desired, in such manner that the vessels, being methodically charged in succession with the material to be operated upon, the heated leys (composed of caustic alkali) can be progressively conducted from vessel to vessel of the series, passing over and through the material placed therein.
The leys are thus used again and again, (each successive change, or charge of ley, carrying forward the extractive matters it has dissolved from the fibre with which it has been in contact) until exhausted or neutralized, (when they are discharged), fresh leys being methodically, and successively, supplied, until by degrees, the extractive matters combined with the fibre or fibrous material have been rendered sufficiently soluble, when hot water for washing, or rinsing, is in the same continuous manner run successively from vessel to vessel, over, and through, the material contained therein, until the extractive matters rendered soluble by the previous alkaline baths have been carried forward and discharged, leaving the residuary fibre sufficiently cleansed.
By this system of boiling in continuity, until all the effective alkali in the leys is exhausted or neutralized, I realize an economy of from 30 per cent. to 40 per cent. of soda over the ordinary process of boiling, and by the subsequent washing, or rinsing, in the same continuous manner, without removing the material from the vessels, the normal structure of the fibre is in a great measure retained, waste is minimized, and thus, while being thoroughly cleansed and freed from extraneous matter, the strength and staple of the fibre are preserved; a considerable saving of fuel results from the heated liquors being used again and again, less steam being required, as also less water, while at the same time economy of both labour and power is effected over the ordinary system.
Assuming the boiling and succeeding washing processes to be concluded, and the material ("Bamboo") in one of the vessels of the series in its regular succession, to be found sufficiently treated and cleansed, a final cooling water is run on and through the fibre, which is then drained, and the contents of the vessel (disconnected for the time being from the series) emptied into a waggon running on a railway, by which it is conducted to a press or otherwise to abstract all the remaining moisture possible.
The dry, or semi-dry fibre, is then submitted to the action of a willow, or devil, by means of which it is opened or teazed out, and converted readily into a tow-like condition, when it is dried by a current of heated air, induced by a fan-blast, and finally baled up for storage or transport, in a similar manner to Cotton or Jute.
In this condition of "Paper-Stock," it may be kept an indefinite length of time without injury, and when received by the Paper-manufacturer requires merely soaking down and bleaching, to fit it for making into paper, either by itself, or used as a blend with other materials, as desired.
The minuter details of my process for treating raw fibres, or fibrous material, for the manufacture therefrom of Fibrous "Paper-Stock," are fully described in my several Patents, the only variation so far as relates to "Bamboo" being the preliminary preparation of the young stems, the other portions of the process being substantially the same as in daily operation at the Ford Works, Sunderland, for the treatment of "Esparto," and other "raw fibres."
I have only now further to remark that the "Plant" required to manufacture "Paper-Stock" from "Bamboo" on an economical and practical working scale, would consist of a battery of boiling pans, with the other necessary adjuncts and machinery, steam engines and steam boilers, such "Plant" being on a scale adequate to the manufacture of 100 tons "Bamboo" weekly, producing therefrom say 60 tons merchantable "Paper-Stock."
As the above scale of operations, viz. the Manufacture of 100 tons ("Bamboo") weekly into "Paper-Stock," may appear somewhat large, it is necessary I should explain that owing to the nature of the Process, the desired effect being produced by the reiterated and continuous action of repeated weak Alkaline Baths or Leys, in a Series of Vessels, such an operation involves the treatment of a large quantity of "Raw Material," at one time, and cannot either conveniently or economically be conducted upon a much smaller scale.
The cost of the "Plant" and Machinery required for such a Factory would amount to about ***, packed ready for shipment in England, to which would have to be added the carriage and cost of erection, with the necessary buildings, which, however, would be of a very simple and inexpensive character.
I do not feel myself competent to determine what quantity of Land would be required for a plantation to supply such a factory, which would absorb 100 tons dry, say 400 tons green, "Bamboo" stems weekly, but assuming 40 tons produce to the acre, with only once annual cropping, 500 acres should be ample. This calculation doubtless would be influenced by the varying conditions of climate and soil, as also by the variety of "Bamboo" cultivated.
It may be expected that I should in these "Remarks" include some reference to the "Variety" of "Bamboo" which could be most economically and profitably cultivated for the supply of such a Factory, on the scale I propose.
In respect to this portion of my subject I experience some difficulty, inasmuch as the Varieties of "Bamboo" are so numerous, and so widely distributed.
A Monograph by Colonel (now General) Munro, C.B., published in the 'Transactions of the Linnean Society,' affords the most elaborate and comprehensive description of the "Bamboo:" in this paper upwards of 170 species are described.
The "Bambusa Vulgaris," as its name indeed denotes, appears to be the most generally distributed, as it is found in both Hemispheres, General Munro being in considerable doubt as to which it is a native of.
I quote from his Monograph: "I have seen it collected by Wallich, in Silhet, by Hooker, in Chittagong (both North-east India), from Ceylon wild, in the Mauritius cultivated abundantly, in the West Indies naturalized, and cultivated in several parts of South America, this is the only thoroughly cosmopolitan species."
Bambusa "Gigantea," growing to the height of 120 feet and from 25 to 30 inches circumference; B. "Edulis," or edible Bamboo; B. "Arundinacea;" B. "Balcooa;" B. "Brandisii," &c., all varying in growth to from 60 to 70, to 120 feet high, abound throughout India, and all our Asiatic Dependencies. In the West Indies also, where not now indigenous, doubtless any variety selected could readily be introduced and cultivated.
To conclude, it would appear that with the "Raw Material" "Bamboo," we have under our control "an embarrassment of riches," and I have only further to add that I know of no other that can at all approach it in economy of production, and I believe very few if any in the quality of the "Stock" produced therefrom suitable for Paper-making purposes.