is the sap of a species of saponaceous forest tree, thousands of which abound in the dense forests of the Malay peninsula.

Of course, the Doctor was not long in disseminating his knowledge of so remarkable a substance. He speedily procured specimens of the tree and its product in various states of preparation, and forwarded them to the Society of Arts in London. As soon as it arrived in this country, its peculiar properties were rigidly inquired into; and, its value in manufactures being speedily ascertained, the gold medal of the Society was awarded to the Doctor as the first discoverer.

This substance derives its name, not from the scientific worldthough it is curious that the first half of the term is the Latin word for drop, whence it might be concluded that gutta percha meant the droppings of the percha tree but from the native Malays. It is pronounced pertsha, not perka.

Dr. Montgomerie had several opportunities of becoming acquainted with the method by which the gutta or sap was obtained from the tree. The fruit yields a "concrete and edible oil, which is used by the natives with their food;" while the sap circulates between the bark and wood of the tree in vessels whose course is sufficiently well marked by black longitudinal marks. At first the natives were in the habit, when they required a supply, of felling the tree; but experience soon taught them that the milky juice might be collected by cutting notches here and there in the trunk, and that in this way the life of the tree might be saved for future "tappings." The sap coagulates in a few minutes after it is collected; but before the crude gum becomes quite hard, it is kneaded by hand into compact oblong masses from seven to twelve inches in length, by four or five in thickness. This part of the work is mostly performed by women. The blocks made up for exportation, however, are not always of uniform size and appearance, the fancy of the rude barbarian sometimes giving them strange forms -such as that of a bird with red berries for eyes, images of ships, quadrupeds, or the "human face divine." The gum is always sold by weight a fact which is taken advantage of by the crafty savage, who, in humble imitation of more clever adulterators, sometimes introduces a stone or a heavy substance into the interior of the mass. As it would entail a serious loss of time on the merchant if he were to cut each block at the port of shipment, it often happens that, on the substance reaching this country, it is found to conceal stones or rubbish; and then woe to the purse and the cutting-knives of the purchasers! Besides this, however, the block often contains a vast amount of unavailable material in the shape of bark, dirt, leaves, and so on, which become accidentally incorporated with the gum.

From the examination of the specimen sent over by Dr. Montgomerie, it became apparent that a large trade in the article would speedily take place; and in a few months the jungles of the Johore

.

Archipelago, in scene of the first gatherings, were explored by Englishmen, Chinese, and Malays, in search of the gum-exuding tree. Their efforts were actively seconded by the natives; and in a short time it was discovered that the supply, of which some doubts had at first been entertained, was almost inexhaustible. It is singular, remarks an acute observer, that, although the Portuguese, Dutch, and English, had, one or other of them, retained possession of the islands on which the trees grow for more than nine centuries and a half, it should have remained for an Englishman to discover their valuable properties at so late a date as 1843.

The rise of this new trade gave a great impulse to the activity of the Oriental islanders; and the value of the gum becoming fully known, eager search was made from island to island, and among the forests of the Archipelago; and large profits were made by the sarmingongs, or chiefs, of the aboriginal tribes, who exacted from the gum hunters a royalty on all they found. Sufficient profit, however, was left, even after this deduction, to stimulate the cupidity of the natives, and the port of Singapore was speedily supplied with the article in great quantities. At present, above two millions of pounds are exported into this country in the manyshaped masses alluded to. We will now inquire into

THE NATURE AND APPLICATIONS OF GUTTA PERCHA.

At the present time the chief supplies of the article come from Singapore, though vast numbers of the tree-the wood of which, being of a soft spongy nature, is of little commercial value are found in Borneo, Java, Sumatra, and Penang. In its nature it differs from indian-rubber chiefly in its superior density and toughness. Though both substances are somewhat alike in appearance and manner of application, the absence of oxygen in indian-rubber may account for its greater elasticity. The chemical constituents of gutta percha, as ascertained by Dr. Maclaghan, areCarbon....... Hydrogen.. Oxygen

....

86.36

12.15

1.49

Exposed to a temperature of 248 degrees, gutta percha melts; and in cooling remains in a semi-fluid adhesive state partially decomposed, in fact; and when set on fire it burns very readily, with a dense smoke. At a temperature of about 200 degrees it becomes soft and ductile, though without stickiness, and can be put into the shape it is intended to retain when cool. Its specific is 975, that of water being 1.000. It is a repellant of, and completely unaffected by, any description of cold water; and of heat

and electricity it is a non-conductor. It is proof against alkalies and acids, being only affected by sulphuric or nitric acid in a highly concentrated state; while the most powerful ascetic, hydrofluoric, or muriatic acids, or chlorine, have no effect whatever on its structure or capabilities. Of its power to resist frost, sufficient proof exists in the number of boot and shoe-soles manufactured from it; and of its acoustic properties we shall have more to say.

The capabilities of the resin were tasted as soon as the specimen forwarded by Dr. Montgomerie reached London, and a kind of historical interest is attached to this sample from the fact that, from this humble beginning, a large branch of manufacture has arisen which now employs some thousands of workmen. Several ingenious tests were applied to the specimens, and it was soon proved, by Messrs. Whishaw and Hancock, that it was applicable to a vast number of purposes; and from it were made tubing, lathe bands, and impressions of medals-all of which were shown at the late Exhibition in Hyde-park. If further proofs of its value were necessary, we need only refer to the experiments made by these gentlemen; one of which consisted in the softening a mass of the material in hot water, pressing it round a soda-water bottle, hardening it in cold water, pressing it out into a thin sheet, and then, by the application of heat, again rolling up the gum into the form at first assumed. From the patents taken out by Messrs. Hancock, arose the manufacturing and trading firm known as the "Gutta Percha Company.'

We will now examine

THE MANUFACTURE OF GUTTA PERCHA.

Perhaps few of our readers think what a vast amount of capital and labour are constantly working hand in hand in the byways of London. We pass through the main streets, and are acquainted with the general complexion of the thoroughfares right and left, but, unless our business leads us directly into the vortex of industry, we bestow little thought upon aught that comes not immediately before our eyes. A few steps out of the main line in one direction take us into the midst of the tan-yards of Bermondsey; a hundred yards or so from Finsbury-square, and we are in a new world among the weavers of rich silken and velvet stuffs; through a street or two from that same square, and we are deafened by the clang of hammers and the din of labour; in every direction, did we care to search, we should find factories where hundreds of men earn the "daily bread" for which, it is to be hoped, they nightly pray. So it is with the spot in which the Gutta Percha Company have their factory. A few yards out of the City-road, near the canal basin, and we find ourselves in a strange neighbourhood, where coals, and lime, and culm, and building materials, are being constantly unloaded from queer-shaped vessels, and were numerous manufactures are being carried on. In this "Wharf-road" are the works we are now visiting.

We enter a modest-looking doorway beside a pair of folding gates, on which the words "Gutta Percha Company" are painted, and we become speedily aware that a branch of manufacture of which we hitherto knew next to nothing is being carried on within. Sight and smell-a smell something like a tanyard, something like old cheese, something like half-dried clothes in a laundry, something like gas-tar-an odour we soon become accustomed to-informs us that we may expect to witness a new sight. And we are not mistaken; for the manufacture of gutta percha has necessitated the invention and use of novel machines, strange processes, and odd-looking tools. Every fresh application of the materialwhether it be the production of merely useful or highly ornamental designs, the imitation of the grain of wood, the close texture of papier-maché, on the endeavour to make this Eastern gum a substitute for leather has necessitated the invention of tools not hitherto thought of, and the use of appliances beyond the range of the ordinary workman. As soon as we are fairly in the yard of the works, we look around and read the history of the manufacture all about us. Here are piled great heaps of the raw material, in all imaginable strange shapes; there, and on every side, are buildings erected especially for the processes to be carried on inside-store rooms, engine-houses, workshops, a quay for unshipping the gum, cum multis aliis.

Let us enter the building nearest us, and, by the help of Mr. Statham, the intelligent manager, and "our own artist," we will endeavour to explain what we witness. The blocks of gutta percha required for use are taken from this heap to the cutting machine. This is a large solid vertical dise of iron, making about two hundred revolutions per minute. The raw material is cut into thin slices by several sharp knives, like those in a carpenter's plane. The block of gutta percha, being brought to the edge of a sloping iron table, is rapidly caught up by the knives, and literally reduced to shavings, which fall into a receptacle beneath. The cutting apparatus, as well as the other machines on the premises, is put in motion through the agency of two fifty-horse power engines, the boilers of which are constructed on a novel plan, by which eleven pounds of water are evaporated to one pound of fuel. The furnaces, moreover, consume their own smcke.

Reduced to shavings, the gutta percha must next be perfectly cleansed of its impurities. This is no easy matter, This is no easy matter, but patience and hot water are certain at last to effect the desired object. The shavings are thrown into great tanks and boiled, and then, the greater part of the rubbish having fallen to the bottom, the gum is collected into one mass and carried to what is called the "teaser"—a sort of large circular box, containing a cylinder or drum, covered entirely with rows of bent, jagged teeth. Revolving at a great rate (about 800 turns in a minute), the "teaser" quickly tears the mass into shreds and tatters, which fall into a vat of

water beneath. The true gutta percha, being lighter than water, floats on the surface, while the impurities sink to the bottom; and thus, being perfectly cleansed of all impurities, is ready, crisp and new-looking, for the succeeding process. Another boiling brings the material again into a soft, compact mass, which is "kneaded" "masticated" in heated iron cylinders, in which revolving drums so completely turn and twist the pasty gum as to bring it into a perfectly homogeneous state, without a particle of water in its composition.

In this state the gutta percha may be considered ready for manufacture, and the subsequent processes are employed either in making it up in sheets or tubes. If required for after use in the production of ornamental articles, the kneaded mass is carried to the rolling machine. This apparatus is similar to that employed in paper mills, the gutta percha passing on an endless band through steel cylinders placed at the requisite distances apart, according to the thickness of the sheet required. By a simple adjustment of the cylinders, it can be made to produce with equal ease the stoutest driving-band or the thinnest tissue so much used and appreciated by surgeons as a substitute for oiled silk, hydropathic bandages, etc. During the passage of the sheet through the machine, it has become sufficiently cooled to form a solid consistent body; or if the substance of the sheet required be too thick to allow it to cool in the ordinary manner, it is blown upon as it passes on to the drum at the end by a series of fans, like those in a winnowing machine. When the material is required to be in strips, a very ingenious construction of knives takes the sheet just before quitting the machine, and cuts it into longitudinal bands of the required width, which are, as before, carried forward on to the drum.

In the production of tubing, a different but highly ingenious and simple process takes place. "A mass of the softened material is forced by a piston through a steel cylinder, terminating in a mould, which consists of a solid circular piece of metal set within an iron tube, the space between the two being the thickness required;"in fact, this is a very curious modification of the wire-drawing process. The gutta percha, after having left the mould in a tabular form, is received into a canal of water about fifty feet in length. The office of the water is to prevent the tube from contracting or collapsing; the pressure being equal both within and without, it is thus preserved in the required shape, and is afterwards dried and hardened by exposure to the air. As the tube

leaves the water it is wound off at the other end, and the "feeding cylinder" is so contrived that no pause occurs in the transmission of the material. By this means a pipe of upwards of 1,000 feet in length has been manufactured in one piece.

From the sheeting and tubing thus prepared an infinite variety of articles are composed. The numerous workshops are crowded