GUTTA PERCHA. This lately-discovered and very useful substance exudes from a tree grown in Singapore, Borneo, and other of the eastern islands. The first specimen seen in England was sent to the Society of Arts, London, in 1843, by Dr. Montgomerie. The first articles made of this substance in England were a lathe-band, a short piece of pipe, and a bottle case, which were presented to the Society of Arts in 1844.
There seem to be three varieties of this substance, named Gutta Girek, Gutta Tuban, and Gutta Percha. The word gutta means a gum which exudes from a tree ; while percha (pronounced pertsha) is the Malayan name for the tree which principally yields this gum. The trees are forest trees, and the natives ap pear to tap the hark when and how they think they may obtain the largest supplies. The gum is brought to England in shapeless lumps, and is then wrought into the secondary forms of rods, tubes, blocks, sheets, strings, &c., preparatory to being manufactured for various useful purposes.
The articles now made of gutta percha are numerous and varied. The toughness of the material (differing somewhat from the elasti city of caoutchonc), and the facility with which it may be softened by heat, render it peculiarly apt to receive, and maintain permanently, any form that may be imparted to it. Pressure in moulds, while the gutta percha is in a warm and plastic state, is one of the most conve nient modes of giving it a determinate form. Whether wet or dry, its uses are confined to cold purposes, as it is very readily affected and thrown out of shape by heat. For many pur poses, naphtha and other inflammable liquids act as cements and even solvents for the gutta perclia. In its usual condition it is a brown substance, and not much unlike very tough leather, but having a peculiar odour; its sur face is, however, capable of being prepared so as to receive paint, gilding, japanning, bronz ing, and other ornamental modifications. The crude substance, as brought to England, is reduced to a pulp by macerating machines, purified by water, combined with many different substances according to the purpose to which it is to be applied, and pressed into sheets or other forms by rollers ; and familiar mecha nical processes are then sufficient to work up this prepared material to the required forms.
It was reasonable to expect that, after gutta percha came into general use, it would be employed in some of the processes of book binding. Accordingly, in 1845, Mr. Nickels patented a method of using gutta percha for cementing together the leaves of books, ex actly in the same way as in caoutchouc bind ing. The cement is a solution made by dis solving gutta percha in rectified naphtha, recti fied oil of turpentine, or some other essential oil. The solution also is used for pasting
down the end-papers, attaching vellum or leather to the boards, sizing the exterior for marbling and gilding, and for mixing with the colour for colouring and marbling edges, &c. Sheets of guttapercha are used as a substitute for vellum, leather, cloth, or paper, in covering books ; or a covering is made by coating a piece of cloth with gutta percha solution. The same material is used as a substitute for paste. board for binding : the flexible boards being made of a composition, in which gutta percha is mixed with paper, pulp, leather dust, wool, or cotton. When for any of the above pur poses a little more elasticity is required than belongs to gutta percha, a little caoutchoue is combined with it.
Lieut. Rouse, Superintendent of the Green tsich Hospital Schools, has lately caused 800 pairs of boys' shoes to be soled with gutta percha ; be states that they are more econo mical than leather, and that the waterproof luality is fully determined. Gutta percha rater-pipes are being gradually substituted for lead. At the Bristol Vitriol Works gutta ?ercha pump-buckets are used. It is em ?loyed as a lining for inuriatic acid casks at he Patent Candle Works. From its power of resisting the most potent chemicals, it is of he greatest service to the chemical mantifac mrer, as he is enabled to use it in many )perations instead of glass or metal. The most concentrated alkalies do not affect it, or any of the acids used in pharmacy or the arts, with the exception of the strongest snl Thuric and nitric acids. Messrs. Mnspratts lave had carboys made and wine pipes lined with it, for the conveyance of muriatic acid by railway, instead of glass ; and so successful ms been the experiment, reducing the car 'iage, and obviating all danger of breakage, hat they are now using nothing else. For he conveyance and stowage of water—entirely preventing the injurious effects arising from drinking water contaminated with lead—it is peculiarly well adapted, as it is not in the least acted upon by the carbonic acid and fixed air which in some waters so readily attack lead. Its applicability to many other chemical purposes, such as funnels, syphons, &c., and for strapping for diseased joints, stopping for decayed teeth, balsam for cuts, catheters, bougies, and stethescopes, is very important. In electrical processes the insulating power of gutta percha is most valuable. Gutta percha was first employed as a cover to the wires in damp tunnels, and its perfect success there suggested the idea of laying down within its protecting folds telegraphic lines between England and the Continent.