These slices show that the gutta-percha is by no means uniform in different parts, either in color or texture. To bring about a uniformity is the object of the shredding or tearing process. The slices are thrown into a tank of water, which is heated by steam to such a temperature as to soften the mass; dirt and heavy impurities fall to the bottom, leaving a pasty mass of gum; and the mass being thrown into another rotating machine, is there so torn and rent, and dragged asunder by jagged teeth, as to be reduced to fragments. The fragments fall into water, upon the surface of which (owing to the small specific gravity of the material) they float, while any remaining dirt or impurity falls to the bottom. These fragments are next converted into a dough-like substance by another softening with hot water, and the dough undergoes a thorough kneading; it is placed in hollow heated iron cylinders, in which revolving drums so completely turn and squeeze and mix the now purified mass, that all parts become alike, and every particle presents a family likeness to its neighbor.
The kneaded state may be considered the dividing line between the preparatory processes and those which relate to the fashioning of the material. The soft ductile mass may be formed either into sheets or tubes. In forming sheets the mass is passed between steel rollers, placed at a distance apart corresponding with the thickness of the sheet to be made—whether for the heels of a rough-booted pedestrian, or for the delicate “gutta-percha tissue,” now so much employed by surgeons. By the time that the substance has passed through the rollers it has cooled sufficiently to assume a solid, firm consistency. By the adjustment of a few knife edges, the sheet may be cut into bands, or strips of any width, before leaving the machine. In making tubes and pipes, the soft mass of kneaded gutta-percha is passed through heated iron cylinders, where a singular modification of the wire-drawing process reduces it to the desired form and dimensions.
From the sheets and tubes thus made, numberless articles are produced by cutting and pressing. Machines, somewhat like those used in cutting paper, are employed to cut the gutta-percha into pieces. If for shoe-soles, a cutting press produces a dozen or so at one movement; if for string, or thread, narrow parallel slips are cut, which are then rounded or finished by hand; if for producing stamped decorative articles, the sheets are cut into pieces, and each piece is warmed and softened to enable it to take the impress of a mould, or die. But the mode of casing copper wire for electro-telegraphic purposes is, perhaps, one of the most singular applications of the material in the form of a sheet. Several wires are laid parallel, a strip of gutta-percha is placed between them, another strip is placed above them, and the whole are passed between two polished grooved rollers; the pressure binds the two surfaces of the gutta-percha firmly together and to the wires, while the edges between the grooves indent the gutta-percha so deeply, that it may easily be separated longitudinally, each slip containing its own core of copper.
GUTTA-PERCHA BOATS.
When Lady Franklin fitted out an expedition in search of her gallant husband, a year or two ago, Captain Forsyth, the commander of the vessel, took out with him a gutta-percha boat, presented for that purpose by Messrs. Searle. His account of the behavior of this boat, under the rough usage to which it was subjected in the ice-bound regions of the north, is most laudatory. He states that “whilst the other boats constructed of wood suffered much by the cutting of the young ice, the gutta-percha boat was not in the least damaged, and returned to England in almost as good condition as when she left, although she underwent all the rough work of the voyage.” Mr. Snow, who had especial charge of the gutta-percha boat belonging to the ‘Prince Albert,’ has detailed in a clear manner the remarkable way in which this material resists the rude buffetings of those regions. It must be remembered that the boat had a skeleton of wood and a covering of India rubber. Mr. Snow says, “The severest trial it endured, and endured successfully, was on both my visits to Whaler Point, Port Leopold. To those unaccustomed to the nature of such ice as was there met with, it will be impossible fully to conceive the position a boat was placed in. The mere transit to and fro, among loose masses of ice, with the sea in a state of quiescence, would have been quite enough to have proved or not the value of gutta-percha boats; but when, as in the present case, those masses were all in restless agitation, with a sea rolling in upon an opposing current, it might have been well excused—and without deteriorating from the previously attested goodness of the article—if it had not been able to have resisted the severe shocks it received.... Sliding through and over the ice; sometimes lifted completely out of the water by the sudden contact of a resistless floe; and at others thrown side-ways upon an adjoining craggy piece; I think it would have been next to impossible for any other kind of boat to have been otherwise than crushed or stove on the instant.” It was in a right spirit that the explorers gave the name of “Gutta-Percha Inlet” to the spot where the boat had rendered them such important service.
GUTTA-PERCHA—MISCELLANEOUS APPLICATIONS.
A rare catalogue we should present, if all the useful applications of gutta-percha were duly set forth. We should have to speak of breast-coating for waterwheels, of galvanic batteries, of shuttle-beds for looms, of packing for steam-engines and pumps, of cricket and bouncing balls, of felt-edging for paper making, of curtain rings whose merit is noiselessness, of window-blind cord and sash lines, of clothes’ lines (recommended to the laundress as defying all attacks of weather,) of bosses for flax-spinning frames, of whips and sticks, of policemen’s and ‘special constables’’ staves, of flax-holders for heckling machines, of skates, of fencing sticks, of washers for the axles of wheels, of plugs or solid masses used in buildings, of buffers for railway carriages, of gunpowder canisters (which ‘keep the powder dry,’) of sheet-covering for damp walls, of linings for ladies’ bonnets, of jar covers, of sponge bags, of foot baths, of funnels, of goldsmith’s bowls, of bobbins for spinning machines, of covers for rollers, of book covers, of moulds for electrotypes, of coffin linings, of sounding boards, of portmanteaus, of beds for paper-cutting machines, of fine and coarse thread, of envelope boxes, of powder flasks, of portfolios, of a stopping for hollow teeth—a tolerable list, this, which shows how multiplied are the applications for which this singular vegetable product is available.
GUTTA-PERCHA—ORNAMENTAL WORK.
When softened by heat, this substance will take the impress of a mould or stamp with delicate precision; and in the course of a few minutes it reassumes its tough state, retaining permanently the pattern given to it. The power of application is thus unlimited, or limited only by the inclination of the purchaser. Whether the mould be of copper or of brass, of pear tree or of box, an impress can equally well be obtained from it. In practice, all these four materials are employed, and sometimes others. The mould being carved and in a state of readiness, the piece of gutta-percha (always, or nearly always, in the form of sheet) is laid upon a marble slab, which is heated by steam from beneath; and the gum being thus brought into a pliant and yielding state, it is placed on or in the mould, a counter mould is laid upon it, and the action of a press forces the material into the minutest parts of the device. If the pattern be deep and the relief bold, a hydraulic pressure of a hundred or a hundred and fifty tons is brought to bear upon it; but if of lighter and simpler character, a hand-press is brought into requisition.
In this way, aided by minor manipulation, are produced the varied and ever-increasing specimens of ornamental gutta-percha work. Trays are produced of every imaginable (or at least of every usable) form and pattern: bread trays, biscuit trays, cotton or work-table trays, counter or card-table trays, pen trays, pin trays, card trays, soap trays, shaving trays, &c. Then there are work-baskets and hand baskets, flower vases and bouquet holders, plates and platters, decanter stands and watch stands, bas-reliefs and alto-reliefs. The desk fittings admit of much beauty in this material; inkstands are produced in most diverse forms; while pen trays, paper weights, wafer boxes, envelope boxes, &c., are beginning to establish a formidable rivalry to the similar articles made in papier-mache. Beauty, pattern, graining, clouding, or whatever we may choose to term it, is produced in a very remarkable way on the surface of gutta-percha. Some specimens of gutta-percha are darker than others, and all have a tendency to darken by age; and the workman dexterously avails himself of these varying tints to produce a pattern. He softens two or more pieces, of different tints, passes them between two rollers to thoroughly unite and amalgamate them, and then presses them into the mould; leaving it to the freaks of chance to bring out the wavy lines, the curls, the streaks, the knots, which the intermixture of tints produces. This diversity is not very apparent at first; but it becomes developed when the substance is polished, and considerably enhances the beauty of the article produced.