The

soluble in benzene, ether, petroleum spirit, and turpentine, but is insoluble in alcohol. It has slightly acid properties and contains a small quantity of bodies capable of combining with caustic soda, but the main bulk has, probably, a terpene composition. residue in the retort sets, on cooling, to a hard, clear, transparent resin, soluble in benzene, chloroform, petroleum spirit, and turpentine to clear solutions; in ether it gives a cloudy solution; it is insoluble in alcohol, but soluble in hot linseed oil.

Copal. The term "copal" is now used very frequently as a generic term, covering a number of resins of various origin. Strictly speaking, it should, when used as a class name, only include resins, of which animi may be taken as a type; but it is made to include resins such as Manila copal, which has very different properties. Accordingly, copals are often divided into two groups-"true copals" and "false copals." The former in

cludes animi and the copals found on the West Coast of Africa, and perhaps also kauri and the Demerara copal. The latter group includes Manila copal, dammar, and a few others. "True copals" are hard, lustrous resins, insoluble in solvents, and require to be fused before they can be made into varnish. The "false copals " vary very much in their properties—some are hard, as dammar, others are soft, as Manila copal. They are more or less soluble in solvents like alcohol, benzol, turpentine, &c.

a fossil It is

Gum copal is a product of vegetable origin found on the West Coast of Africa, over a district extending from latitude 8° N. to latitude 4° S., a distance of some 700 miles. In this district very large quantities of copal is found, as resin, in the ground at various depths up to about 10 feet. dug for by the natives during the rainy season only, which extends from March to May. Generally it is found in the superficial strata of marl, clay, and sand, which are sufficiently soft in the wet season to permit of being easily worked, but in the dry season they are too hard for the negroes to dig into with the rather primitive tools they use. The botanical origin of copal is not known with certainty. Some authorities assign it to a tree called Guibourtia copallifera, while it is quite possible that it comes from more than one species; certainly, no tree which is at present growing on the copal coast yields this gum. This fact, together with its occurrence in very recent deposits and the existence of the pebble copals in the beds of the rivers of this district, show that it is most likely to be the produce of various species of trees which have grown or now grow in inland districts. Probably, as the interior of the copal districts become better known, the source of the resin will be discovered. After

the resin has been collected, it is carried by the natives, along with other produce which they collect at the same time, to the ports for export to Europe, America, &c. The principal ports from which copal is thus exported are Sierra Leone (from which the best copal is obtained), Accra, Benin, Gaboon, Loango, the Congo, Angola, Benguela. The copals obtained from these places are not identical in properties, some being harder than others.

Sierra Leone copal is the best quality of copal imported from Africa. It usually comes over in the form of rough angular pieces, almost colourless or, at the most, having a faint yellow colour. It is hard, has a specific gravity of 1-054, is quite insoluble in all the ordinary solvents, and only becomes soluble after it has been fused, the melting point being 400° F. (205° C.). It is very lustrous, and makes a first-class and very durable varnish. By careful selection of the resin used pale varnishes can be made from this copal. Sierra Leone copal is the variety most in use in making cabinet and coach varnishes, for the best grades of which the finer pieces of copal are picked out, the commoner kinds being used for inferior grades.

Pebble copal also comes from Sierra Leone. It occurs in the form of rounded pieces, varying slightly in size, and is mostly colourless; but some samples are slightly coloured, mostly pale brownish-yellow. It is very hard (perhaps the hardest of the copals), and its specific gravity is about 1.055. From its form it has evidently been transported from the interior by the rivers, in whose beds it is now found. Owing to the supply being small and somewhat uncertain, varnish makers are rather shy of using Pebble copal, although it makes a good varnish resin.

Angola copal is found in the three districts of Angola, Benguela, and Congo, the copal from which are so much alike that in commerce they are classed together as Angola copal," or, as it is often called from its colour, "red Angola copal." It is generally in the form of globular pieces, although flat pieces are often met with. The size is usually about 1 to 2 inches, but large pieces about 5 to 6 inches have been found. This copal is generally covered with a reddish crust about one-sixteenth of an inch thick. When this crust is removed, the resin is usually found free from colour or, at most, has a faint yellowish colour; occasionally brownish pieces are found. The darker coloured pieces are often the freest from air bubbles-bits of bark, wood, &c., which are often found in the colourless variety. These, therefore, command a higher price in the market. Angola copal is not so hard as those above described. It yields a good quality of varnish, brilliant and durable. Its specific gravity is 1.065.

Angola copal only comes into commerce in small quantities; almost too small to induce varnish makers to use it.

Gaboon copal is found in rounded, flattened pieces, varying in size from about to 2 inches; in colour it is the darkest of the copals-a sherry colour; transparent; but, as a rule, not homogeneous. The surface is generally smooth, but some pieces have a crust, which is sometimes striated.

Loango copal differs from other copals in being found in the form of cylindrical pieces, which are evidently only portions broken off much larger pieces; two varieties are known, red and white; the former is, as its name indicates, of a reddish or faint brownish colour, and is rather larger than the latter and more cylindrical in form; the white varies in colour from colourless to faint yellow. The red is the best and, on account of its being more homogeneous, more lustrous and harder than the white, is both more in demand and brings a higher price in the market.*

Demerara Copal.-This fossil resin comes from the locust tree, Hymenaea Courbarii, of British Guiana. It is collected much in the same manner as animi and copal, and, when freed from the outer crust, has a splendid lustrous appearance, being quite clear and transparent, perfectly homogeneous and often occurring in large masses; pieces of from 10 to 12 lbs. weight are frequently found, while a mass weighing at least 60 lbs. was shown at the Manchester Exhibition in 1887.

It has a specific gravity of 1030 and melts at about 240° to 250° C. (450° to 465° F.); it gives off a large proportion of volatile oil and gas, and leaves but little solid resinous matter as compared with animi; thus, weight for weight, it does not make as strong a varnish as animi or copal, but, allowance being made for this fact, it is an excellent varnish resin. It is also known as Demerara animi.

Ether dissolves it, alcohol causes it to swell to a white jelly, chloroform causes it to swell and dissolves a part of it, petroleum ether causes it to swell to a white jelly.

Kauri. This is a very important copal-like resin found in New Zealand in large quantities, which has only comparatively recently come into use as a varnish resin. It is also known as Cowdee gum, Kowree, Cawree gum; there are various other

of spelling the name.

ways

This resin is the product of various species of New Zealand pine trees, chiefly from Dammara Australis, which yields by far

*Copal is slightly soluble in turpentine on long digestion with the solvent, but it is nearly insoluble in other media, which at the most only cause it to swell, while but a small portion passes into solution.

the larger proportion of the resin sold. Other species are Dammara ovata and D. Cookii of New Zealand, while in Queensland, D. Brownii, and in New Caledonia, D. lanceolata, yield the resin in small quantities. Most of the resin used is dug out of the ground. It is found all over the Colony, mostly in

the Province of Auckland where but few trees exist now. There is no regular organised system of searching for the resin, but a very large, although variable, number of persons, mostly natives, are engaged in the collection of it. The resin is found at various depths, from a few inches to several feet below the surface, on which, however, there are no indications of its presence below; large pieces are often turned up in ploughing cultivated lands. The resin digger uses two tools, a spear, which is a long, sharppointed, wooden-handled steel rod of about inch in diameter, and a spade. With the spear he pierces the ground and feels for the resin; experience soon tells him when he has touched a piece, and then he digs down to it; the find may only be a small one, or, as occasionally happens, very large pieces are found. The surface of the resin is covered with a thick crust of decayed vegetable and resinous matter which is removed by the digger before he sells it to the merchant. Besides the fossil resin, kauri is also obtained from the living trees; such resin is known as "young" kauri, and it differs from fossil kauri in being almost colourless and softer. The trees, when they are cut, bleed profusely and yield a pale yellowish viscid fluid which dries into a hard resinous mass; both old and young trees yield the resin, and it is no uncommon thing to find in old trees deposits of the resin. The stumps of felled trees soon become covered with a thick layer of kauri resin. The trees are fast disappearing, and soon no "young" resin will be obtainable.

Kauri comes into the market in pieces varying much in size, from a few inches to two feet, and in weight, from 1 lb. to cwt. The best quality is known as "dial" kauri, but many varieties are recognised in the trade. In colour it varies but little, being mostly of a pale amber or pale brown. Some samples are homogeneous, others are more or less streaked; the former kind are usually clear and transparent, while the latter are often opaque. In lustre it varies from glassy to opaline. It breaks with a conchoidal fracture, and freshly-broken pieces have a fragrant odour which is very characteristic. The taste is pleasant and aromatic. It is used by the Maoris of New Zealand as a chewing gum, especially the "young" kauri. The specific gravity is 1.050, New Caledonia kauri being rather heavier than New Zealand kauri. It melts easily at from 360° F. to 450° F.; and

on distillation it gives about 14 per cent. of water and from 16 to 20 per cent. of oil of specific gravity 0·9224, soluble in ether, but insoluble in alcohol, and caustic soda.

Kauri is used in varnish making as a rival to copal, but, although the varnish it yields is a good one, yet it is far from equalling copal varnish, not being so durable. When exposed to the weather it has a tendency to become powdery, but, being hard, it is largely used in varnishes for interior work and, to a limited extent, in the preparation of ornaments. Petroleum spirit, alcohol, turpentine, and benzol cause kauri to swell up to a white opaque mass dissolving a portion of it; chloroform and amyl alcohol partially dissolve it, ether completely. melting, the gum is soluble in ether, petroleum spirit, turpentine, benzol, and chloroform to clear solutions. There are, however, variations between different samples of kauri in their solubility in these media.

After

Sandarac. This resin has quite different properties to the copals above described. It is used in making both oil and spirit varnishes, although for the former kind its use is decreasing. It is also known as gum juniper. It is the produce of the Alerce tree, Callitris quadrivalvis, a tree indigenous to North Africa, in the mountain regions ranging from the Atlantic coast to at least as far East as Eastern Algeria, but possibly further. The resin is found exuding naturally from the trees. The Moors who collect it are in the habit of making small incisions in the bark of the tree for the purpose of increasing the amount of flow of the sap, and, therefore, the quantity of resin; after collection it is taken to Mogador for export to Europe.

Sandarac occurs in the form of short cylindrical pieces or tears, which are sometimes agglomerated together; in colour it is a yellowish white; it is a comparatively hard resin, being about equal to kauri or rosin in this respect; it melts easily at about 300° F. (150° C.), and breaks with a clean, lustrous fracture. The specific gravity is 1038 to 1.044.

It is soluble in alcohol, amyl alcohol, and ether, partially soluble in benzol, petroleum spirit, and turpentine, but very slightly soluble in oil, before fusing, yet readily so after fusing. It is used in making pale spirit varnishes, and is valued on account of the hardness and lustre of the coat it forms.

Rosin or Colophony.-The name of this body is spelled rosin or resin; the former is more in accordance with the pronunciation of it and will be adopted here; the latter is liable to confusion with the generic name for the group of resins. Colophony is rarely used. Rosin is obtained in the distillation of turpentine