Part 20

Common turpentine is mostly employed as an ingredient in the plasters used by farriers. The oil is occasionally used in medicine; and, lately, it has been considered efficacious in cases of worms. It is much employed by painters for rendering their colours more fluid; as well as in the composition of different kinds of varnish used in floor-cloth, umbrella, and other manufactures. The noxious spirit called gin was formerly flavoured with juniper berries; but as these are now too expensive, oil of turpentine, the taste of which in a slight degree resembles that of juniper, is applied to the same purpose; and considerable quantities of turpentine are thus consumed. The common resin is used in plasters, for which its great adhesiveness renders it peculiarly applicable. It is also of considerable importance in the arts; and musicians rub the bows and strings of violins with it, to take off the greasy particles which are there collected, as well as to counteract the effects of moisture. Yellow resin is used in plasters, and for other purposes in medicine.

_Tar_ is obtained from the roots and refuse parts of the fir-tree, by cutting them into billets, piling these, in a proper manner, in pits or ovens formed for the purpose, covering them partly over, and setting them on fire. During the burning, a black and thick matter, which is the tar, falls to the bottom, and is conducted thence into vessels which are placed to receive it, and from which it is afterwards poured into barrels for sale.

Tar is an article of great utility in manufactures, and for various economical purposes. It is much employed for smearing the rigging, and other external parts of ships, to prevent their receiving injury from moisture. It has been used in medicine both internally and externally; and particularly _tar-water_, or water impregnated with tar, was, some years ago, a popular remedy in various disorders, but its virtues have been too much extolled. Although considerable quantities of tar are prepared in this country, these are insufficient to supply the demand; consequently we, every year, import great quantities of it from Russia, Sweden, America, and other countries.

_Pitch_ is usually made by melting together coarse hard resin and an equal quantity of tar; or, as some writers state, by boiling tar with a certain portion of water, until it becomes so thick that, on cooling, it forms a hard black mass.

By the ancients pitch was much employed for giving flavour and fragrance to their wines. With us it is of extensive use to mechanics, and in numerous manufactures; but the principal demand for it is in ship-building, to secure the joints and crevices of the planks and timbers, and for other purposes. When mixed with a certain quantity of oil and suet, it is made into _shoe-makers' wax_; and, in conjunction with whale fat, forms _carriage-grease_, or the substance with which the wheels of carriages are smeared. The best pitch is imported from Sweden and Norway: and, is of a glossy black colour, perfectly dry, and very brittle.

_Lamp-black_ is a soot formed by burning the dregs and coarser parts of tar in furnaces constructed for that purpose. The smoke is conveyed through tubes into boxes, each covered with linen, in the form of a cone. Upon this linen the soot is deposited: and it is, from time to time, beaten off into the boxes, and afterwards packed in barrels for sale. This substance is employed in printing and dyeing; and has its name from the practice that was formerly adopted of making it by means of lamps.

247. _The WEYMOUTH PINE is chiefly distinguished by its leaves growing in fives, and its cones being smooth, cylindrical, and longer than the leaves._

This species of fir-tree grows wild in North America, and succeeds well in strong land in England. Its _timber_ is white, of more open grain than Scots fir, and not so heavy as that. In America it is principally used for the masts of ships, for which, by its toughness, it is peculiarly calculated.

248. _The SPRUCE FIR_ (Pinus abies), _a native of Norway, and other Northern parts of Europe, is known by its short, and four-sided leaves growing singly, and surrounding the branches; its cones being cylindrical, the scales somewhat square, flattened, and notched at the top_

The _wood_ of the spruce fir is what the English carpenters usually denominate _white deal_. It is considered next in value to that obtained from the Scots fir; and is remarkable for having few knots. On account of its lightness it is peculiarly adapted for packing-cases and musical instruments.

From incisions made into the trunk of the spruce fir-tree, a fine and clear _turpentine_ oozes, which, after being boiled in water, and strained through a linen cloth, acquires a somewhat solid consistence, and reddish brown colour; and is called _Burgundy pitch_. This is employed as an ingredient in several kinds of ointments and plasters: and is principally manufactured in Saxony.

The article called _essence of spruce_, which is used in making spruce beer, is prepared from the branches of this tree, and from those of a species nearly allied to it which grows in America.

249. _The LARCH_ (Pinus laryx), _a native of the Alps, and the mountains of Germany, is a species of fir, which has its leaves in tufts, and its cones oblong, and of somewhat oval shape, the margins of the scales bent back, and jagged._

The cultivation of larch-trees has of late been much recommended for adoption in this country, on account of the value of their _timber_, which for strength and durability, is equal to most kinds of deal. It is well calculated for masts, and the framework of vessels, being capable of sustaining much greater pressure even than oak. For wood-work constantly immersed in water, it is peculiarly calculated, as, in such situations, it is asserted to become almost as hard as stone. In Petersburg larch timber is applied to no other use than that of ship-building. Line-of-battle ships are constructed of it in Archangel, and these generally last about fifteen years; though, in milder climates, it is imagined that they would last much longer.

For gates, pales, and similar work, exposed to the vicissitudes of weather, they are admirably serviceable; and for flooring and other internal purposes are at least equally durable. Buildings constructed of larch timber are said to have continued sound for 200 years; and, in some of the old palaces in Venice, there are beams of larch yet existing that are as sound as when they were first placed. But the very combustible nature of this wood renders it objectionable for such uses. No wood with which we are acquainted affords more durable staves for casks than larch; and, in the opinion of many persons, it is further valuable by improving the flavour of the wine contained in them. The wood is of delicate colour, not unlike the cedar used for black-lead pencils, but is knotty almost throughout.

From the _inner bark_ of the larch the Russians manufacture a soft and fine kind of white gloves. The trunk, if tapped betwixt the months of March and September, yields an extremely pure turpentine, which has the name of _Venice turpentine_; and is of considerable use in medicine. It is usually thinner than any other kind of turpentine, and of clear, whitish, or yellowish colour. The drug of this name, which is generally met with in the shops, is now imported from New England, but was formerly brought from Venice. A brown gummy substance, known in Russia by the name of _Orenburgh gum_, is obtained by a curious process from the sap of the tree. On the large branches of the larch are produced small, sweetish grains, somewhat resembling sugar; which are frequently substituted for the drug called manna (275).

The cultivation of the larch was first introduced into Britain towards the conclusion of the seventeenth century. The trees will grow in almost any soil; and the proper season for felling them is the month of July. They, however, seldom attain any large size in this country; and they are said to decay and become covered with moss, when about forty years old.

250. _The CYPRESS-TREE_ (Cupressus sempervirens) _is a dark-coloured evergreen, a native of the Levant, the leaves of which are extremely small, and entirely cover all the slender branches, lying close upon them so as to give them a somewhat quadrangular shape._

_In some of the trees the branches diminish gradually in length from the bottom to the top, in such manner as to form a nearly pyramidal shape._

In many of the old gardens in this country cypress-trees are still to be found, but their generally sombre and gloomy appearance has caused them, of late years, to be much neglected. They are, however, very valuable on account of their _wood_, which is hard, compact, and durable, of pale or reddish colour, with deep veins, and pleasant smell. We are informed by Pliny that the doors of the famous temple of Diana, at Ephesus, were of cypress wood, and that, although they were 400 years old at the time when he wrote, they appeared to be nearly as fresh as new. Indeed this wood was so much esteemed by the ancients, that the image of Jupiter in the capitol was made of it. The gates of St. Peter's church at Rome are stated to have been of cypress, and to have lasted more than 1000 years, from the time of the Emperor Constantine until that of Pope Eugenius the Fourth, when gates of brass were erected in their stead. As this wood, in addition to its other qualities, takes a fine polish, and is not liable to suffer from the attacks of insects, it was formerly much esteemed for cabinet furniture. By the Greeks, in the time of Thucydides, it was used for the coffins of eminent warriors; and many of the chests which enclose Egyptian mummies are made of it. The latter afford very decisive proof of its almost incorruptible nature.

The name of this tree is derived from the island of Cyprus, in the Mediterranean, where it still grows in great luxuriance. Its gloomy hue caused it to be consecrated by the ancients to Pluto, and to be used at the funerals of people of eminence. Pliny states that, in his time, it was customary to place branches of the cypress-tree before the houses in which persons lay dead.

251. _The CASSAVA, or CASSADA_ (Jatropha manihot) _is a South American shrub, about three feet in height, with broad, shining, and somewhat hand-shaped leaves, and beautiful white and rose-coloured flowers._

It is a very remarkable circumstance, that the _roots_ of the cassava, if eaten raw, are a fatal poison both to man and beast, and that, when prepared by heat, they yield a safe and valuable food; on which, indeed, many both of the Indian and European inhabitants of South America almost wholly subsist. The roots are the only edible parts of the plant. These, which are white, soft, and farinaceous, from one to two feet in length, and five or six inches in circumference, are dug out of the earth, at a certain season of the year, washed, stripped of their rind, and ground to a pulp. The juice, or poisonous part, is pressed out, and carefully thrown away; as cattle, and other animals, which have accidentally drunk of it, have almost instantly died. The flour that remains, after pressure, is formed into thin round cakes and baked. To an European, accustomed to other bread, these, though sweetish, and not unpalatable, have an insipid taste. If placed in close vessels, and preserved from the attacks of insects, cassava bread may be kept for several months without injury.

With the natives of South America, it is not unusual to throw a great number of cakes of cassava together to heat, after which they soak them in water, which causes a rapid fermentation to take place; and from the liquor thus obtained, they make a very sharp and disagreeable, but intoxicating beverage, which will not keep longer than twenty-four hours without spoiling.

From the pure flour of cassava is formed the substance called _tapioca_, which is frequently imported into this country, and is used for jelly, puddings, and other culinary purposes. It is prepared from the fibrous part of the roots by taking a small quantity of the pulp, after the juice is extracted, and working it in the hand till a thick white cream appears on the surface. This, being separated, and washed in water, gradually subsides to the bottom. After the water is poured off, the remaining moisture is dissipated by a slow fire, the substance being constantly stirred, until at length it is formed into grains about the size of sago (266). These become hard by keeping, and are the purest and most wholesome part of the cassava.

The roots of another species of this shrub, called _sweet cassava_, are usually eaten with butter, and merely after being roasted in hot ashes. They have much the flavour of chesnuts, and are an agreeable and nutritive food.

252. _The TALLOW TREE_ (Croton sebiferum) _is a native of China, and in habit somewhat resembles a cherry-tree, but has shining egg-shaped, and pointed leaves, that form tufts at the extremity of the branches._

The _fruit_ of this tree, from which the Chinese obtain a kind of tallow for the manufacture of candles, is enclosed in a husk, not much unlike that of the chesnut, and consists of three round white kernels. All the preparation that is requisite is to melt these kernels, adding a little oil, to render them softer and more pliant than they would otherwise be. The candles made from this substance are very white, but are sometimes coloured by adding a little vermilion. They are more firm than those of tallow, but not equal in quality to candles either of wax or spermaceti. The wicks that are used are not, like ours, made of cotton, but consist of little rods of light, dry wood, with the pith of a rush entwined round them.

253. _INDIAN RUBBER, or CAOUTCHOUC, is the dried juice of a large and much branched tree_ (Siphonia elastica, Fig. 60), _which grows in Guiana, and other parts of South America._

_This tree has somewhat oval leaves, entire, veined, and smooth, arranged in threes, and on long foot-stalks._

_The flowers are small, in bunches, near the ends of the branches, and the fruit is triangular._

It was not until about the year 1736, that this very extraordinary natural production was made known in Europe. It is obtained by making incisions through the bark of the tree, chiefly in wet weather. From the wounds thus formed the juice flows abundantly. It is of milky-white colour, and is conducted by a tube or leaf, supported by clay, into a vessel placed to receive it. Some writers assert that, on mere exposure to the air, it gradually hardens; and others that, for this purpose, it goes through a certain process, which the Indians keep a profound secret. It is usually brought to Europe in the shape of pear-shaped bottles, which are formed by spreading the juice over a mould of clay. These are exposed to a dense smoke, or to a fire, till they become so dry as not to stick to the fingers; and then, by certain instruments of iron or wood, they are ornamented on the outside with various figures. This done, the clay in the inside is moistened with water and picked out.

Indian rubber is remarkable for the flexibility and elasticity which it acquires on attaining a solid state; and also for the numerous useful purposes to which it is capable of being applied. By the Indians it is sometimes formed into boots, which are impenetrable by water, and which, when smoked, have the appearance of leather. Bottles are made of it, to whose necks are fastened hollow reeds, through which the liquor contained in them can be squirted at pleasure. One of these, filled with water, is always presented to each of the guests at their entertainments. Flambeaux are likewise formed of this substance, which give a very brilliant light; and it is said that a torch of Indian rubber, an inch and a half in diameter, and two feet long, will burn twelve hours. The inhabitants of Quito prepare a species of oil-cloth with the hardened juice of this tree.

The principal uses to which Indian rubber is applied by us are, for the effacing of black-lead marks; for flexible syringes, tubes, and other instruments used by surgeons and chemists; and for the formation, by means of turpentine or linseed oil, of a varnish for air-balloons.

Various experiments have been made to dissolve this substance, so that it may assume its naturally elastic state, under any figure that may be required. This has been effected by means of ether, but the process is too expensive for common use. A simple method of forming tubes of it is to split a piece of cane and to put between the pieces a slip of whalebone. If the Indian rubber be cut into slips, and twisted closely round the cane, and the heat of boiling water be applied, the whole will become united into one piece or tube, from which the whalebone first, and afterwards the cane, may easily be separated.

It has been proved that cloth of all kinds may be made impenetrable by water, if impregnated with the fresh juice of the Indian rubber tree; and that boots, gloves, and other articles, made of cloth thus prepared, may be joined without sewing, and only by moistening the edges with the juice. These are not only more durable, but retain their shape better than such as are made of the juice without any connecting substance.

It has lately been ascertained that, in Prince of Wales's Island, and also in Sumatra, there are trees of a class and order totally different from that above described, which yield a juice similar to this, and applicable to all the same purposes.

254. _The CASTOR-OIL PLANT_ (Ricinus palma christi) _is a native both of the East and West Indies, and has a stem from five to fifteen or sixteen feet in height, and large bluish-green leaves, divided into seven lobes, serrated and pointed, the footstalks long, and inserted into the disk._

_The flowers are produced in a terminating spike, and the seed-vessels are covered with spines, and contain each three flattish oblong seeds._

It is to the seeds of this plant that we are indebted for the drug called _castor-oil_. This is sometimes obtained by pressing the seeds, in the same way as is practised with respect to oil of almonds (152). But the mode chiefly adopted in the West Indies, whence we principally import it, is first to strip the seeds of their husks or pods, and then to bruise them in a mortar; afterwards they are tied in linen bags, and boiled in water until the oil which they contain rises to the surface; this is carefully skimmed off, strained to free it from any accidental impurities, and bottled for use. The oil which is obtained by boiling is considered more mild than that obtained by pressure, but it sooner becomes rancid. The mildest and finest of the Jamaica castor-oil is limpid, nearly colourless, and has scarcely more taste or smell than good olive-oil.

The uses of castor-oil in medicine are well known.

The plant is sufficiently hardy to grow and ripen its seeds in the open ground of gardens, in the south of England.

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CLASS XXII.--DIOECIA.

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DIANDRIA.

255. _WILLOW, OSIER, or WITHY._--Of this very extensive tribe nearly fifty distinct species have been discovered in our own island. The slender branches of many of these are applied to useful purposes, but particularly for making baskets, bird-cages, and what is called wicker-work; springles for fastening down thatch, wheels or traps for catching lobsters and eels; hoops and crates. The _wood_ is useful for the handles of hatchets, prongs, spades, and other rural implements; and also furnishes shoemakers with cutting and whetting boards, on which they cut leather and sharpen the edges of their knives.

As willows generally flourish in wet situations, some of the species are planted with a view to prevent the banks of rivers and brooks from being washed away by floods.

The _bark_ of some kinds of willow has been applied, with effect, as a substitute for Peruvian bark, in the cure of intermittent fevers. It has also been esteemed useful in the tanning of leather; and, in combination with alder, for striking a deep black colour, in the dyeing of linen.

The bark of other species may be manufactured into paper. In the year 1788, Mr. Greaves of Milbank, near Warrington, Lancashire, made fifteen reams of coarse paper from the bark of withen twigs, intermixed with a few nettles. The latter, however, he afterwards discovered, would better have been left out, as there was in them a woody substance, which does not well incorporate with other vegetables. The paper he made was considerably cheaper than paper of equal size and thickness made from ropes; and it was found that pasteboard, for book covers, made of withen bark, would be much cheaper than similar pasteboard manufactured from ropes. The process by which this paper and pasteboard were manufactured was as follows; the bark was stripped from the twigs in September, the time at which they are usually cut for making white baskets; it was then hackled, like flax or hemp, and dried in the sun, which gave it somewhat the appearance of brown hemp: but this having been attended with considerable trouble, other parts of the bark were dried with the leaves, as they were stripped off from the twigs, and were then submitted to the operation of the paper-mill.

The flowering branches of one species, the _common sallow_ (_Salix cineria_), are called palms, and are gathered by children, in many parts of England, on Palm Sunday.

TRIANDRIA.

256. _NUTMEGS are the kernels of a fruit produced in several islands of the East Indies._

_They are each surrounded by the spice called_ mace, _and, externally, by a husk about half an inch in thickness, which has somewhat the appearance of a small peach_ (Fig. 80).

_The nutmeg-tree_ (Myristica aromatica) _is not unlike our cherry-tree, both in growth and size. Its leaves are nearly oval, but pointed, waved, obliquely nerved, of bright green colour above, and whitish beneath. The flowers are small, and hang upon slender stalks._

When this fruit is nearly ripe the husk opens at the end, and exposes a net-work of scarlet mace. Underneath the mace is a black shell, about as thick as that of a filbert, and very hard; and in this is contained the nutmeg.

The gathering of _nutmegs_ is performed by persons who ascend the trees for that purpose, and pull the branches to them with long hooks. The husks are stripped off in the woods, and the remaining part of the fruit, with its surrounding mace, is taken home. After the mace has been carefully stripped off, with a small knife, the nuts, which are still covered with their woody shell, are dried, first in the sun, and then upon a frame of split bamboos placed over a slow fire, until, when shaken, the kernels are heard to rattle within the shells. These now easily fly to pieces when beaten with small sticks; and the nutmegs, being taken out, are soaked in sea-water and lime, and are then thrown in great numbers together to heat, by which their vegetating principle is destroyed. The nutmegs are finally sorted into parcels, according to their quality, and packed in bags for sale and exportation.