the name given in California to a kind of sand-bath employed by the natives in the cure of the venereal disease. It is prepared by scooping a trench in the sand, two feet wide, one foot deep, and of a length proportioned to the size of the patient; a fire is then made through the whole extent of it, as well as upon the sand which was dug out of the hollow. When the whole is thoroughly heated, the fire is removed, and the sand-flamed about, that the warmth may be equally diffused. The sick person is then stripped, laid down in the trench, and covered up to his chin with heated sand. In this position a very profuse sweat soon breaks out, which gradually diminishes according as the sand cools. The patient then rises and bathes in the sea, or the nearest river. This process is repeated till a complete cure is obtained. While the patient is undergoing the operation of the tamascal, he drinks a considerable quantity of a warm sudorific, prepared by the decoction of certain herbs, chiefly of the shrub called by the Spaniards GOVERNANTE, which see in this Supplement.

TAN is a fuliginous found in most vegetables, which, not having hitherto been resolved into component parts, is therefore considered as simple. See Vegetable and Animal Substances in this Suppl.

TANNING is an art, of which a full account, according to the general practice in London and its vicinity, has been given under the proper title in the Encyclopaedia. But since that article was written, the superior knowledge which has been obtained of the tan- The tanning principle, as well as of the composition of the skins of animals (See Vegetable and Animal Substances, Suppl.), has suggested to scientific artists various methods of shortening the process by which leather is manufactured. Mr Seguin is said to have thrown much light upon the art of the tanner as it is practised in France; and in 1795 Mr William Defmond obtained a patent for practising Seguin's method in England. He obtains the tanning principle by digesting oak bark, or other proper material, in cold water, in an apparatus nearly similar to that used in the saltpetre works. That is to say, the water which has remained upon the powdered bark for a certain time, in one vessel, is drawn off by a cock, and poured upon fresh tan. This is again to be drawn off, and poured upon other fresh tan; and in this way the process is to be continued to the fifth vessel. The liquor is then highly coloured, and marks, as Mr Defmond says, from six to eight degrees on the hydrometer for salts. He calls this the tanning lixivium. The criterion to distinguish its presence is, that it precipitates glue from its aqueous solution, and is also useful to examine how far other vegetable substances, as well as oak bark, may be suitable to the purpose of tanning. The strong tanning liquor is to be kept by itself. It is found by trials with the glue, that the tanning principle of the first digester which receives the clear water, is, of course, first exhausted. But the same tan will still give a certain portion of the attrac- tant principle, or gallic lixivium, to water. The presence of this principle is ascertained by its striking a black colour when added to a small quantity of the solution of vitriol of iron or green copperas. As soon as the water from the digester ceases to exhibit this sign, the tan is exhausted, and must be replaced with new. The gallic lixivium is reserved for the purpose of taking the hair off from hides.

Strong hides, after washing, cleaning, and fleshing, in the usual way, are to be immersed for two or three days in a mixture of gallic lixivium and one thousandth part by measure of dense vitriolic acid. By this means the hair is detached from the hides, so that it may be scraped off with a scalded knife. When swelling or raising is required, the hides are to be immersed for ten or twelve hours in another vat filled with water and one five-hundredth part of the same vitriolic acid. The hides being then repeatedly washed and dressed, are ready for tanning; for which purpose they are to be immersed for some hours in a weak tanning lixivium of only one or two degrees; to obtain which, the latter portions of the infusion are set apart; or else some of that which has been partly exhausted by use in tanning. The hides are then to be put into a stronger lixivium, where in a few days they will be brought to the same degree of saturation with the liquor in which they are immersed. The strength of the liquor will by this means be considerably diminished, and must therefore be renewed. When the hides are by this means completely saturated, that is to say, perfectly tanned, they are to be removed, and slowly dried in the shade.

Calf-skins, goat-skins, and the like, are to be steeped in lime-water after the usual fleshing and washing. These are to remain in the lime water, which contains more lime than it can dissolve, and requires to be stirred several times a day. After two or three days, the skins are to be removed, and perfectly cleared of their lime by washing and pressing in water. The tanning process is then to be accomplished in the same manner as for the strong hides, but the lixivium must be considerably weaker. Mr Defmond remarks, that lime is used instead of the gallic lixivium for such hides as are required to have a close grain; because the acid mixed with that lixivium always swells the skins more or less; but that it cannot with the same convenience be used with thick skins, on account of the considerable labour required to clear them of the lime; any part of which, if left, would render them harsh and liable to crack. He recommends, likewise, as the best method to bring the whole surface of the hides in contact with the lixivium, that they should be suspended vertically in the fluid by means of transverse rods or bars, at such a distance as not to touch each other. By this practice much of the labour of turning and handling may be saved.

Mr Defmond concludes his specification, by observing, that in some cases it will be expedient to mix fresh tan with the lixivium; and that various modifications of strength, and other circumstances, will present themselves to the operator. He affirms that, in addition to the great saving of time and labour in this method, the leather, being more completely tanned, will weigh heavier, wear better, and be less susceptible of moisture than leather tanned in the usual way; that cords, ropes, and cables, made of hemp or flax, impregnated with the tanning principle, will support much greater weights without breaking, be less liable to be worn out by friction, and will run more smoothly on pulleys; inasmuch that, in his opinion, it will render the use of tar in many cases, particularly in the rigging of ships, unnecessary; and, lastly, that it may be substituted for the preservation of animal food instead of salt.

Mr Nicholson, from whose Philosophical Journal we have taken this account of Mr Defmond's method of tanning, made some very proper enquiries at one of the first manufacturing houses in the borough of Southwark, concerning its value. He was told by one of the partners, that the principle upon which the new process is founded had been long known to them; but that they preferred the old and slower method, because the hides are found to feed and improve in their quality by remaining in the pits. He could gain no satisfactory information of what is meant by this feeding and improving; and, without taking upon us to decide between the advantages peculiar to Defmond's method and those of the common practice, we cannot help saying that this objection of the tanner at Southwark appears to us to be that of a man who either understands not the principles of his own art, or has some reason for opposing the progress of improvement, if it do not originate in his own house.

Tassie (James) modeller, whose history is intimately connected with a branch of the fine arts in Britain, was born in the neighbourhood of Glasgow of obscure parents; and began his life as a country stone mason, without the expectation of ever rising higher. Going to Glasgow on a fair day, to enjoy himself with his companions, at the time when the Foulis's were attempting to establish an academy for the fine arts in that city, he saw their collection of paintings, and felt an irresistible impulse to become a painter. He removed to Glasgow; and in the academy acquired a knowledge of drawing, which unfolded and improved... improved his natural taste. He was frugal, industrious, and persevering; but he was poor, and was under the necessity of devoting himself to stone-cutting for his support: not without the hopes that he might one day be a flautist if he could not be a painter. Referring to Dublin for employment, he became known to Dr Quin, who was amusing himself in his leisure hours with endeavouring to imitate the precious stones in coloured pastes, and take accurate impressions of the engravings that were on them.

That art was known to the ancients; and many specimens from them are now in the cabinets of the curious. It seems to have been lost in the middle ages; was revived in Italy under Leo X. and the Medici family at Florence; became more perfect in France under the regency of the Duke of Orleans, by his labours and those of Homburg. By those whom they instructed as assistants in the laboratory it continued to be practised in Paris, and was carried to Rome. Their art was kept a secret, and their collections were small. It is owing to Quin and to Tassie that it has been carried to such high perfection in Britain, and attracted the attention of Europe.

Dr Quin, in looking out for an assistant, soon discovered Tassie to be one in whom he could place perfect confidence. He was endowed with fine taste; he was modest and unassuming; he was patient; and possessed the highest integrity. The Doctor committed his laboratory and experiments to his care. The associates were fully successful; and found themselves able to imitate all the gems, and take accurate impressions of the engravings.

As the Doctor had followed the subject only for his amusement, when the discovery was completed, he encouraged Mr Tassie to repair to London, and to devote himself to the preparation and sale of those pastes as his profession.

In 1766 he arrived in the Capital. But he was diffident and modest to excess; very unfit to introduce himself to the attention of persons of rank and of affluence; besides, the number of engraved gems in Britain was small; and those few were little noticed. He long struggled under difficulties which would have discouraged any one who was not possessed of the greatest patience, and the warmest attachment to the subject. He gradually emerged from obscurity, obtained competence; and what to him was much more, he was able to increase his collection, and add higher degrees of perfection to his art. His name soon became respected, and the first cabinets in Europe were open for his use; and he uniformly preserved the greatest attention to the exactness of the imitation and accuracy of the engraving, so that many of his pastes were sold on the Continent by the fraudulent for real gems. His fine taste led him to be peculiarly careful of the impression; and he uniformly destroyed those with which he was in the least dissatisfied. The art has been practised of late by others; and many thousands of pastes have been sold as Tassie's, which he would have considered as injurious to his fame. Of the fame of others he was not envious; for he uniformly spoke with frankness in praise of those who executed them well, though they were endeavouring to rival himself.

To the ancient engravings he added a numerous collection of the most eminent modern ones; many of which approach in excellence of workmanship, if not in simplicity of design and chastity of expression, to the most celebrated of the ancient. Many years before he died he executed a commission for the late Empress of Russia, consisting of about 15,000 different engravings (See Gem. Encycl.). At his death, in 1799, they amounted to near 20,000; a collection of engravings unequalled in the world. Every lover of the fine arts must be sensible of the advantage of it for improvement in knowledge and in taste. The collection of Feloix at Paris consisted of 1800 articles; and that of Dehn at Rome of 2500.

For a number of years, Mr Tassie practised the modelling of portraits in wax, which he afterwards moulded and cast in paste. By this, the exact likeness of many eminent men of the present age will be transmitted to posterity as accurately as those of the philosophers and great men have been by the ancient statuaries. In taking likenesses he was, in general, uncommonly happy; and it is remarkable, that he believed there was a certain kind of inspiration (like that mentioned by the poets) necessary to give him full success. The writer of this article, in conversing with him repeatedly on the subject, always found him fully persuaded of it. He mentioned many instances in which he had been directed by it; and even some, in which, after he had laboured in vain to realize his ideas on the wax, he had been able, by a sudden flash of imagination, to please himself in the likeness several days after he had last seen the original.

He possessed also an uncommonly fine taste in architecture, and would have been eminent in that branch if he had followed it.

In private life Mr Tassie was universally esteemed for his uniform piety, and for the simplicity, the modesty, and benevolence, that shone in the whole of his character.