OXALIC ACID. THE name of this acid is derived from a plant, in scientific language called Oxalis acetosella. Its common name is wood-sorrel. From the juice of this plant oxalic acid may be obtained in considerable quantities, as it may also from that of the Rumex acetosa, or common sorrel, and the several varieties of rhubarb.

Oxalic acid was discovered about sixty years ago by SCHEELE, a celebrated Prussian chemist. There is reason to believe that it exists in a much greater number of plants than is generally suspected.

It having been remarked that the shoes of persons who had been walking in a field of chick-peas* were curiously corroded, it occurred to a French chemist that this effect must have been produced by some property possessed by the plant. On cutting off some of the fine hairs of the chick-pea, they were found to yield an acid liquor, which, on further examination, proved to be an aqueous solution of pure oxalic acid. It rarely happens, however, that the acid is found pure. In the plants we have mentioned, as furnishing it in the greatest abundance, it almost always occurs in combination either with potash or lime.

Compounds formed of oxalic acid and other substances are denominated oxalates. Hence the union of the acid with potash constitutes oxalate of potash, with lime, oxalate of lime, and so on with many

others.

It has lately been ascertained that several kinds of lichent, a species of plants which are generally, although improperly, called mosses, contain nearly half their weight of oxalate of lime. These plants, we are informed, thrive in barren places, and even on rocks, where no other vegetable could exist for a single day; their peculiar constitution admirably adapting them for preparing the way for a higher order of vegetable life.

By this simple fact we are forcibly reminded that all the operations of Divine Providence are the result of design; exhibiting, in their minutest particulars, special thought and foresight. To an unreflecting observer, the humble lichen just mentioned may appear so insignificant, as scarcely to deserve the name of a plant. Let him not thence infer a waste, or a misapplication, of creative power. The Most High has formed nothing in vain. In the economy of nature an important office has been assigned to the lichen, and for its due performance it is endowed with functions no less remarkable than those of the most fragrant flower, the most beautiful shrub, or the most stately tree. In common with other vegetable productions, the lichen possesses, what may with propriety be termed, a power of selecting those particles of matter which are best fitted for its growth and maturity. Man, with all his justly-valued stores of knowledge, would labour in vain, were he to attempt to make oxalate of lime out of the materials the lichen has to work with. That little plant "toils not, neither does it spin," but it manifests capabilities for appropriating from the rock, or other surface to which it adheres, from the moisture with which it is occasionally refreshed, and from the atmosphere with which it is surrounded, just what is necessary for its nourishment, whilst that of an opposite tendency is uniformly rejected. At length it falls into decay, and in its place springs up a distinct order of

The chick-pea is a native of Spain. It is smaller than the

common pea.

+ Lichens appear in the form of thin flat crusts, covering rocks and the bark of trees, or in foliaceous expansions, or branched like a shrub in miniature. Some of them resemble elly, whilst others consist only of a powdery substance.

plants. These owe their existence, on the particular spot they occupy, to the ruins deposited there by their predecessors. Hence we learn, that whilst "we often overlook what is petty, nothing, however small, is deemed worthless, or is disregarded by Him whom no name or language can sufficiently describe, whose power is omnipotence, whose presence is universal, whose knowledge is omniscience, whose creations extend and constitute space, and whose existence is eternity."

Oxalic acid is easily made by dissolving lump-sugar in aqua-fortis (nitric acid), a circumstance which has caused it to be sometimes called acid of sugar. By the action of nitric acid, many other substances besides sugar are converted into oxalic acid. Of these we may here mention starch, gum, most of the vegetable acids, several varieties of fruit, wool, hair, silk, and the whites of eggs.

To chemists, the composition of oxalic acid is a subject of great interest, and has engaged a very large share of their attention. We fear it would not be so to our general readers, for whose sake we purposely abstain from employing a greater number of chemical, and other scientific terms, than are really

necessary.

Those who have read an account of oil of vitriol (sulphuric acid) ‡, will probably remember that oxygen is there mentioned as imparting to sulphur its acid properties. In the instance before us we are equally indebted to its agency. Oxygen is the acidifying principle in oxalic acid, which contains it combined in certain proportions with carbon (the chemical name for charcoal). The acid crystallizes in slender four and six-sided prisms, which, when quite pure, are perfectly white and very brilliant.

At a temperature of 50°, pure oxalic acid requires about fifteen times its own weight of water to dissolve it; at 57°, nine times its weight is sufficient; the solubility rapidly increasing with the increase of temperature. As the oxalic acid of commerce frequently contains minute quantities of nitric acid, the presence of the latter so greatly facilitates the solvent properties of water, that at 60° it often happens that oxalic acid may be dissolved in twice or three times its weight of that fluid.

Oxalic acid, as may be justly inferred from its name, is sour. Its acid properties are so intense, that if one grain be dissolved in 3600 grains of water, there will be sufficient acidity to be perceptible to the taste; and Professor Brande informs us, that in 200,000 (two hundred thousand) times its weight of water, the acid may be detected by means of a very simple test.

The uses of oxalic acid are not very numerous. In the arts, it is chiefly employed by calico-printers, and by straw and Leghorn bonnet-makers. In domestic economy, it is used for cleaning boot-tops. This circumstance, viewed in connexion with the carelessness with which medicines are sometimes vended and taken, and the resemblance which the crystals of the acid bear externally to those of Epsom salt (sulphate of magnesia), has occasioned many fatal instances of poisoning. It is gratifying, however, to observe that these accidents occur less frequently than formerly.

Nothing can be easier than to detect an error of the kind to which we have alluded,-by simply tasting the crystals, or, if they have been dissolved, the be oxalic acid, no mischief can possibly ensue; solution. By doing this, even should it happen to and as that is intensely sour, it cannot for a moment be mistaken for Epsom salt, the flavour of which, See Saturday Magazine, Vol. X.,

P.

139.

although not positively salt or bitter, yet partakes in an eminent degree of both. Moreover, if the crystals of the two substances be closely examined, it will be found that they are not exactly alike, and the exercise even of ordinary caution, first, by observing, and next by tasting, will enable most persons to distinguish the one from the other.

Several acids which are termed poisons, destroy life, when taken into the stomach, solely by their violent action upon the parts with which they come in contact. It seems, however, that oxalic acid is literally a very active poison; instances having occurred in which it has proved fatal when diluted with large quantities of water, and used as an acidulated drink. A quarter of an ounce of the crystals, it is believed, is sufficient to produce death.

It is imperative on those who have occasion for this dangerous material, not only to put it in a place of security, but they ought never to keep it with medicines of any kind. In addition to this, let us impress on them that no circumstances can ever justify them in permitting it to be purchased by children.

When, by accident or design, oxalic acid has been taken or administered, the symptoms of which are great pain, with a burning sensation at the stomach, accompanied by violent retchings, prompt measures are demanded. There may not always be a choice of antidotes at hand, but we will enumerate several, any one of which, if judiciously and instantly applied, might be the means of preserving life. Chalk, whiting, or magnesia, mixed either with warm or cold water, are the best antidotes with which we are acquainted. In the absence of all these, which is not very likely, soda, lime, or even soap and water, may be substituted. The object must be, not only to dislodge the poison from the stomach, but to arrest its influence on the system generally, and this will be effected by the means we have indicated, as oxalic acid forms with lime, magnesia, and soda, salts which are not poisonous. In such a case, however, it is scarcely necessary to remark that no time should be lost in procuring medical assistance.

WOODY FIBRE,

AS AN ARTICLE OF FOOD.

R. R.

A MOST important article of vegetable food, however unpromising it may at first sight appear, is LIGNIN, or WOODY FIBRE. It is true, that wood, or sawdust, does not sound palatable; but when we consider it, spun, as it were, into those delicate tissues of cells and tubes which form the receptacles of the pulp and juices of our most delicious fruits, sometimes yielding an agreeable and crisp resistance, as in the apple; and at others, melting down in a more attenuated form, as in the beurré pear and the peach; For as forming the more substantial skeleton, as it were, of our eatable vegetables, as in the lettuce, cabbage, French bean, and others; we at once see its claims to a place among esculent, and even nutritive principles.

The accumulation of the elements of which woody fibre is composed, by the organic powers of the vegetable world, is something very surprising: the dry timber of an average-sized oak weighs, for instance, about sixty tons; its durability, and its density in some kinds of timber, is also wonderful; so are its uses and applications in the varied forms into which it is elaborated by the hand of Nature; as in hemp, flax, cotton, &c., and the different fabrics into which it is manufactured, such as canvass, linen,

calico, paper, and so forth; giving us cables, ropes, thread, &c.

To the chemist all these things appear still more remarkable, when he finds that the woody fibre, or ligneous part of vegetables, is analogous in compostion to the neutral products, starch, gum, and sugar; and that they are in fact mutually convertible; for woody fibre is a hydrate of carbon, regarded in reference to its atomic constitution; so that, assuming, as just stated, that the woody fibre of a moderate-sized oak weighs sixty tons, we have here a consolidation of thirty tons of charcoal or carbon, and thirty tons of water.

When woody fibre comes before us as an article or diet, it has other curious and important bearings. If any form of lignin, such as saw-dust (cleansed from all foreign bodies, such as resin, extractive matter, &c.), rags, or paper, be rubbed up with a little sulphuric acid, taking care that the action of the acid does not go to the extent of charring, and if the acid be afterwards abstracted by adding to the mixture an alkali, or some powdered chalk, it will be found that the wood has been changed into a species of gum. if we now boil this gum for some hours in acidulated water, (imitating the process for the conversion of starch into sugar,) it gradually becomes converted into sugar. hay, straw, leaves, shavings, in short, any form of ligneous fibre, may be similarly converted; and although we do this but clumsily and inconveniently in our laboratories, being, as we are, but Nature's journeymen, Nature herself carries on these transmutations with the most wonderful results, as we see in the ripening of fruits, where the hard woody texture gradually softens down into sweet and luscious pulp, as in the ripening of the pear, the grape, the strawberry, and, in short, almost all fruits.

Lastly, let us look at the effect of heat on wood. If we burn wood in the open air, it undergoes apparent, but far from real, destruction, as we have already remarked: burned with imperfect access of air, its most volatile and combustible parts go off, and its charcoal, or at least a considerable part of it, remains: if distilled, instead of burned, tar, oil, water, and vinegar, are produced; but if pure woody fibre, such as beech saw-dust, from which all soluble matters have been carefully washed out, be reduced to a very fine powder, and then cautiously roasted or baked, it acquires characters not unlike those of corn-flour, and when duly mixed with yeast, or leaven, it ferments, and makes an uniform spongy bread, much more palatable than that usually eaten by the peasantry of many parts of Europe, and infinitely preferable to that which is made in times of scarcity from bran and the husks of corn.

Such is a short outline of the history of the WOODY FIBRE, considered merely in reference to its chemical properties; and should a subject be at any time required for an essay on the power, wisdom, and goodness of God in the works of the creation, a more prolific or apposite one could scarcely be selected.

[Abridged from the Magazine of Popular Science.]

As the harmony and solidity of a building can only be secured by a strict attention to every part of the structure, which can then, and then only, be considered as complete, when nothing can be withdrawn or altered, without a striking injury to the whole; so also in education, if any part whatever be either omitted or displaced, there will always be some defect or obliquity remaining which injures the whole effect.-BISHOP OTTER,

POPULAR LEGENDS AND FICTIONS.

VIII.

SUPERSTITIONS OF THE SHETLANDERS. MANY of the superstitions of the Shetlanders may be supposed to have descended from their Scandinavian forefathers, and to be parts of that system which prevailed when the heathen worship of Odin, and the belief of Valhalla, prevailed over all the North. But there are other parts of these superstitions which probably had their origin in the peculiar local situation of the Shetlanders, as a people inhabiting a wild and solitary country, and exposed to all the danger and uncertainties of a seafaring life. We accordingly find that the sea-monster called the Kraken, said to appear like a floating island, is still believed to exist; and that mermen and mermaids are said to be seen upon the shores, and around the remote and solitary isles. Seals, and some other animals, are regarded as beings of an intelligent nature, who have come up from a beautiful and splendid world, far below the depth of the ocean; and many curious stories are current of wonderful adventures which certain individuals have had with these incarnate spirits.

Some of these stories are exceedingly amusing, and the reader will find a few such in a work published some years ago by Dr. Hibbert, relative to the Orkney and Shetland Isles. We cannot, however, omit noticing that the Shelty, or Shetland pony, is, as he ought to be, a most important personage in the system of superstition. It is in this shape that they suppose that the god, or spirit, who presides over the waters makes himself visible; and he is also believed to have the power of seeing the ghosts of those who have recently departed :

When a medical gentleman, (says Dr. Hibbert,) of the last century, was returning home from visiting a female, whom he had left at least alive, the Shelty on which he rode suddenly began to snort and gallop; and, on looking behind him, to see the cause of the alarm, he saw the spectred form of the patient he had visited, and soon afterwards heard of her death, which occurred at the exact time when she took it into her head to frighten the Shelty and his rider.

It was usual with the Shetland sorcerers, like the ancient Scandinavian magicians, to use incantations.

I know a song, (said Odin,) of such virtue, that, were I caught in a storm, I could hush the winds, and render the air perfectly calm.

But the warlocks and witches of Thule used, by the same means, to raise tempests, the lay being accompanied by some simple process that denoted the advancement made towards the attainment of the malevolent object.

About thirty years ago, a woman of the parish of Dunrossness, known to have a deadly enmity against a boat's crew that had set off for the Haaf, took a wooden basin called a cap, and allowed it to float on the surface of a tub of water; then, to avoid exciting suspicion, went on with her usual domestic labours, and, as if to lighten the burden of them, sang an old Norse ditty. After a verse or two had been recited, she sent a child to the tub, and bade him tell her if the cap was whummilled. The little messenger soon returned with the news that there was a strange swell in the water, which caused the bowl to be sadly tossed about. The witch then sang still more loudly, and, for the third time, sent the child to the tub to report the state of the basin, who hastened back with the information that the water was frightfully troubled, and that the cap was whummilled.

The enchantress, on hearing the fate of the cap, with an air of malignant satisfaction, ceased her song, and said, "The turn is done!" On the same

day, news came that a fishing yawl had been lost in the Roust, and that the whole of the crew had been drowned.

A similar story is told of some women in the island of Fetlar, who, when a boat's crew had perished in the bay of Femzie, were detected sitting round a well, muttering mysterious words over a wooden bowl that was supernaturally agitated.

The accompaniment of an incantation by some process indicative of the progress of the magical purpose that is meditated, may be found in many of the wild superstitions of Scandinavia, of which the following is a specimen. While the Nornies, or destinies, of Pagan times, were within the recesses of a gloomy cave, dooming, in a wild song, the fate of the warriors who were to fall with the Earl of Orkney in an engagement on the Irish coast, they were employed in a strange loom, where human entrails formed the materials for the warp, foemen's heads for treadles, and swords dipped in gore for shuttles. When the incantation was ended, the women each tore a portion of the cloth, and, mounting their horses, six rode away towards the north, and six to the south.

There is also in Scandinavia an ancient rhyme called the Quern Song, wherein two female slaves of a gigantic form sing a strange ditty, while they are employed in labouring in a quern of immense magnitude, in which they grind riches to a sea-king; but being dissatisfied with the oppression of their master, in making them work throughout the whole of the night, they grind against the same warrior a destructive army.

The ceremony practised by Norna of the Fitful Head, for restoring the heart of Minna, as described in the Pirate by Sir Walter Scott, by melting lead and dropping it into water, is still in use; as is also that of dropping pieces of money into the chapel of Our Lady. In the island of Foula, Dr. Hibbert's guide endeavoured to point out to him the situation of the brilliant carbuncle, which throws out its native light even amidst the gloom of the darkest night,—a superstitious belief of which the author of the Pirate has also made a beautiful application.

In some of the northern islands, the Norwegian, called also the Norse, language, is still spoken. They also retain the ancient usages of the Celts, as described by the oldest and best authors, but with a strong tincture of the feudal constitution. Their shanachies, or story-tellers, supply the place of the ancient bards, so famous in history, and are the historians, or rather genealogists, as well as poets, of the nation and family.

ON DIET.

DR. ARNOTT gives the following amusing summary of the powers of the steam-engine, and of the objects upon which they have been employed.

In its present perfect state, the steam-engine appears a thing almost endowed with intelligence. It regulates with perfect accuracy and uniformity the number of its strokes in a given time, and counts and records them moreover, to tell how much work it has done, as a clock records the beats mitted to work, the briskness of the fire, the supply of of its pendulum; it regulates the quantity of steam adwater to the boiler, the supply of coals to the fire; it opens and shuts its valves with absolute precision as to time and manner; it oils its joints; it takes out any air that may accidentally enter any part that should be vacuous: and when anything goes wrong, which it cannot of itself rectify, it warns its attendants by ringing a bell;-yet, with all these talents, and even when possessing the power of a hundred horses, it is obedient to the hand of a child:-it. never tires, and wants no sleep; it is not subject to malady, when originally well made; and only refuses to work, when

THE MOUNTAIN OF SALT AT CARDONA, IN SPAIN.

a great distance from East to West; on the riverfront its sides are nearly perpendicular. That part from which the salt is quarried is about three-quarters of a mile from the town, in a little valley, one side of which faces that part of the mountain which is overlooked by the Castle of Cardona, while the opposite side is surmounted by a circular portion of the same mountain, named the Bosch del sal, or "Wood of Salt," because formerly this portion was covered with a wood of fir-trees: at present it is covered with vines, which succeed well in about one foot in depth of vegetable earth, with which the salt is covered. The salt is of various colours in the lump, but when bruised, it is of a beautiful white.

Nothing is comparable to the appearance of the Mountain of Cardona at the rising of the sun, for, in addition to its beautiful outline, it seems to rise from the river like a mountain of precious stones, or an immense group of the brilliant prismatic colours, produced by the rays of the sun when passed through

a prism.

I have often regretted (says La Borde,) my inability to convey, by means of the graver, any idea of the brilliant tint which time has impressed on these ancient ruins; what power can represent the play of the rays of the sun on the reflecting surfaces of this chain of crystal, the dazzling effect of which the eye itself can scarcely support? My visit to this place recalled to my mind what I experienced on visiting the salt-mines of Wieliska, in Poland. I had just left school, and full of the reading of Virgil and Homer, I fancied myself transported to the abode of Tethys, or the Palace of Glass of the Nereids; there I

spectacle of the mountain, as it reared its head in the clear blue sky of Spain, I could fancy that I was gazing on a rainbow fallen to the earth.

This mountain of salt includes the ground on which the town is built, and extends to about three miles round it; one division is called the "Mountain of Red Salt," because the red tint predominates, although in reality the colours vary according to the height of the sun, or the less or greater quantity of rain that has fallen. At the foot of this mountain a fountain of water gushes from a large cavity, which extends from the summit to the base; this fountain discharges itself into the river, which, after heavy rains, becomes so salt as to destroy the fish, but three leagues lower down, the water again recovers its freshness. The whole of the hills are full of crevices, caverns, and even spacious grottoes, filled with salt stalactites, in the form of bunches of grapes of different colours, and with other singularly-formed crystallizations. The inhabitants have an idea, that pieces of this salt are good for the rheumatism, and accordingly employ it for that purpose. Numerous works of art are made by the turner from the more solid pieces, such as crosses, chandeliers, statues of saints, &c.

These salt-works have been worked for a grea length of time; they are mentioned in a charter of Bernard Amat, Viscount of Cardona, in the forty third year of the reign of Philip the First of France, that is, in the year 1103.