-414 EXPERIMENTS ON RESISTING THE AGENCY OF FIRE. parates them, and when dressed a little, they bear a considerable resemblance to fibres of silk or flax. This filamentous nature, and the power of enduring a red heat, without any very apparent loss of substance, have long rendered amianthus celebrated among minerals. All its names are in allusion to these properties, or their applications to useful purposes. Asbestos, for example, the original term. comes from the adjective aσßeσtos, inextinguishable, from a supposed practice among the Greeks, of using the mineral to form wicks for their perpetual or sepulchral lamps. Amianthus, also bears, in its etymology, an indirect allusion to the effects of fire. The word auiavros, which signifies "incapable of being soiled," was given in consequence of the facility with which articles manufactured from this mineral were cleansed by means of fire. - Other names were bestowed upon it, which may be briefly noticed-the Romans called it Linum Vivum, both from its resemblance to flax and its indestructibility. It was also named Linum Indum, L. Montanum, L. incombustible, Lana Montana, Salamandra lapidea, &c. The last name seems to have arisen from a conjecture that the fable of the salamander originated from a practice among the ancients of purifying by heat the various fabrications of this mineral. Asbestos and amianthus, are the terms which have passed into the principal European languages. We have the most positive records, that this substance was in use among the Greeks and Romans for the purpose of manufacturing articles in imitation of linen. The workmanship and quality, if we credit the testimony of Pliny and Plutarch, must have been of a very superior character. The former writer ranks the amianth cloth next in quality to the byssus, or fine cotton, worn by wealthy ladies.Plutarch also states, that this mineral was wrought into head ornaments for females. It does not appear, however, that the art of weaving it was sufficiently general to render the cloth cheap. Indeed, every circumstance seems to show, that this fabric must have been an article of luxury among the ancients; and there certainly was an obvious, though, perhaps, excusable parade of its incombustible properties upon all occasions. The practice in Pliny's time, and which be describes as an eye-witness, was to Loss the napkins of amianth into the 1 fire, after a repast or banquet, in order that the grease and dirt might be burnt out. Each guest thus delighted in becoming his own washer. The same vain and clumsy display, we may observe, is recorded of the first dafphin, Charles V., during whose reign, amianthus manufactures seem to have been established at Venice, Louvain, and other parts of Europe. Pliny notices another very important use of mineral cloth, namely, as a shroutelor wrapper, for the bodies of kings, in order to preserve their ashes distinct from those of the funeral pile. That such a practice existed we have positive proof, independently of the historian's testimony, by the discovery, in 1702, near the Porta Næva at Rome, of a funeral urn, ornamented with elegant lusso) relievos, and containing a skull with some calcined bones-a quantity of ashes was also found enclosed within a cloth of amianthus, nine Roman palms long and seven wide. This relic was deposited in the Vatican Library, by order of Pope Clement XI. The very diminutive size agrees but badly with Pliny's account of its use, and will serve to caution us against confidence in his othe· exaggerated statements. It is said, that the disuse of burning the dead occasioned the decline of the manufacture sof these cloths, until the arts became entirely extinct in Europe. The correctness of this opinion will be noticed presently. Threads, nets, net-work, head-ornaments, napkins, table and funeral cloths, seem to have constituted nearly all the articles manufactured sof amianthus in former times. Bonnets, gloves, purses, girdles, ribands, and even paper, have been subsequently made from it. The process by which the mineral fibre was anciently woven is not transmitted to us. In 1691, Ciampini, of Rome, published the following plan in his work, de incombustibili lino ;" and it may be considered nearly as precise as the nature of such manufacture will permit. Having steeped amianthus in warm water, divide its fibres, by gently rubbing them together between the fingers, so as to loosen and separate all the extraneous matter; then pour on, repeatedly, very hot water, as long as it continues to be in the least discoloured. After this, nothing will be left but the long fibres, which are to be carefully dried in the sun. The bundles are then to be carded by very fine instruments, and the long filaments thus obtained steeped in oil to render them more flexible. Acsmail quantity of cofton wool, predlagandis EXPERIMENTS ON RESISTING THE AGENCY OF FIRE. next to be mixed (taking care that the /mineral fibre is in every part the priacipal material, and smoothly adjustsed); by means of a spinning-wheel, the whole is to be drawn into a thread. -The cloth being woven, in the usual manner, is placed upon a clear charcoal sfire, and made red hot, so as to burn out the vegetable or animal matter, &c. The remaining tissue will consist of pure white amianth. This kind of cloth has also been made, without the assistance of other substances, by rubbing and soaking the mineral fibres until they become so delicate and soft, as to admit of being spun at once into threads. This is the process recommended by Madam Perpeuti. 4 The very short fibres which separate during the repeated washings, may be subsequently worked into pasper. For this purpose, however, they require to be well-beaten, until reduced to an impalpable powder, and, subsequently, to be worked up with a large quantity of size in water. These precautions are far more necessary for the amianth than for cotton or linen paper, in consequence of the much greater weight of the mineral paste. After the paper has been formed, the sizing is burnt out. We will now briefly trace the decline sof the mineral weaving, &c. It is apt to be the most glaring characteristic of the antiquarian virtuoso to lament the loss of certain arts among the moderns, nor does utility always constitute an item of his regrets. The ancient process for weaving amianth cloth appeared to be extolled, not from any accurate knowledge of the fact, but because a hint or two about its superior quality may be found among a few writers of antiquity. One of these authorities (Pliny), it is true, compares it with the byssine cloth, obtained from the neighbourhood of Elis, and which Iwas very much esteemed; but while the thus intimates its superiority, he elsewhere bears indirect testimony that the cloth was used merely as a rare and curious article. This writer furnishes three strong reasons why amianth cloth could not have been in common use among the Romans. The first is, the difficulty of procuring the mineral. It is described as occurring on the deserts and parched grounds of India, where rain never falls, and where serpents and other formidable reptiles abound. Secondly, it is stated that the ainianthus, when obtained, was very scarce, and commanded a price equal to that of the most costly pearls. Lastly, it is ex 415 pressly noticed that the workmanship was exceedingly difficult, on account of the shortness of the fibre. These statements are not only in opposition to the belief that the ancients used such articles generally, but the last one goes far to contradict the assertion of Pliny himself respecting the quality. We have, however, a still stronger fact to show, that even in the rich and luxurious times of the Roman empire, the mineral eloth was not in much use for the purpose of collecting the ashes of the dead. Out of the immense number of ancient sepulchres opened in Italy during modern times, not more than one such cloth has ever been discovered, and that (found at Rome, 1702,) is of very coarse texture, and too small to answer the purpose of a wrapper for the body. In several urns charcoal was found mixed with the ashes, a circumstance indicating no great care. "The truth is, that the cloth has always ranked as a curiosity, and, not unfrequently, has had bestowed upon it properties calculated for the credulous and ignorant. Pliny, who was ever too partial to hearsay records, has condescended to state, upon the authority of one Anaxilaus, that amianth cloth, merely wrapped round a tree, has the power of depriving the blow of a hatchet of all sound! The same relish for the marvellous, no doubt, `induced Marco Polo to state, that the body of our Saviour was in his time, preserved at Rome in a shroud of amianth, or incorruptible cloth. Athanasius Kircher, (a Jesuit of the 17th century,) in his Mundus Subterraneus,' also extols this mineral with all the zeal of a connoisseur, He boasts of having in his collection a paper-screen, and a lady's veil of it, together with a lamp-wick, which had burnt for two years without consuming, and which, he wisely adds, will last for ever, if not stolen. Whether this wick is still in operation, we have not learnt; but may venture to conclude, notwithstanding the testimony of partial advocates, that the decline of the art afterwards among the moderns is wholly owing to the insignificance of the articles manufactured. "Experiment has abundantly proved, that although the amianth fibres are alone able to resist a red heat without much change, they soon (even in twenty-four hours) become incapable of transmitting a full supply of oil, owing to an imperfect cohesion effected by the flame. Hence it is impracticable to convert them into perpetual lampwicks. Neither is it true that a red heat has no effect upon them, Cloth, woven of amianth, actually does lose weight by burning; and, after repeating the operation several times, the fibres become so brittle, as to render it difficult to prevent them from crumbling to pieces. In two experiments made be fore the Royal Society of London, a cloth, one foot long by six inches wide, and weighing nearly 1 ounce, was found to lose, by the application of a red heat, more than one-twelfth of its weight each time. It would be considered a very bad piece of common linen that could be worn out out in twelve washings!-The only advantage which such cloth seems to possess over the ordinary kind, is the facility of cleansing it by fire; but, really soap is so cheap an article, that there could not be much gained in this respect by a change in fabrics. The amianth paper has even less to recommend it. It would be curious, no doubt, to return_an.answer upon the same piece of paper as that which was received from the postoffice, merely by burning out the original; but it could not be agreeable to find our ink spreading at every letter, an inch wide, upon paper from which the fire had removed all sizing. So, also, it might appear highly important to possess an incombustible paper, upon which could be spread all important documents; but (not to mention the thousand methods of getting rid of the troublesome records without burning them) we must bear in mind, that an unalterable ink is as important as the paper, and none of those proposed has been found to be sufficient. Incombus: tibility alone must compensate for the article being heavy, coarse, weak, liable to blot, and not capable of taking the full impress of types. Books, it is true, have been printed upon this kind of paper, among which may be noticed the work preserved in the library of the Royal Institute of France; but, however highly authors may esteem their own productions, we feel fully persuaded that booksellers would not tolerate such nonsense from them nowa-days. To conclude, it may be ob served, that, while it is not, by any means, our wish to interfere with the virtuoso's taste for neck-handkerchiefs and shirts of stone cloth, we must take the liberty of hinting, that, if the perfect art of weaving it does not now exist, there is not much lost." SQUEEZING WAX. Sir,-Being a subscriber of your very valuable Magazine, I should feel greatly obliged if some of your numerous correspondents would favour me with the receipt for making wax that is sometimes used by carvers and modellers for taking impressions of carved ornaments, &c. I believe its proper name is squeezing, wax, and the great difficulty is in making it tough and not sticky. Hoping that some one of your many liberal-minded readers will favour me with particulars sufficient to enable me to make it. I am, Sir, With sincere respect, Warwick, Nov. 18, 1829. W. COOKES. MISCELLANEOUS. Poor-House Gardens. An excellent suggestion appeared lately in the Gardener's Magazine -that of having extensive gardens annexed (it is not meant locally) to parish poor-houses. It is very justly stated, that there is no description of labour in which all descriptions of persons, young and old, male and female, could so universally be of use, and that with the least irksonieness of all kinds of toils-the cultivation of a garden is the delight of labour. God Almighty," says one of the wisest men that ever adorned humanity, first planted a garden; and, indeed, it is the purest of human pleasures. It is, moreover, peculiarly favoured in this, that while it is the pleasantest of all descriptions of labour, it is for the gratification of simple events the most profitable also; and therefore the sugges tion of the Gardener's Magazine is a hint which we think may be improved on with much advan tage in the highest quarters, to which the cousİdecation of a provision for our poor extends." Blackwood's Magazine. Erratum. Sir, I perceive there is a mistake In the second line of my communication of the decay of stone cornices, &c, (vol. xii. p.259) which I have no doubt you will be kind enough to notice in your list of errata. In the Maga zine it reads, "It appears to me that the quick decay of the corner parts of mouldings" but it ought to read, "It appears to me that the quick decay of the upper parts of mouldings." Yours, &c. PIT. LONDON: Published for the Proprietor, by M. SALMON, at the Mechanics Magazine Office, No. 115, Fleet Street; where Comma nications for the Editor (post paid) are requested to be addressed. Mechanics' Magazine, MUSEUM, REGISTER, JOURNAL, AND GAZETTE. The prefixed draught is that of a projected machine to be affixed to the sides of vessels and submerged; and which, by indicating their rate, might supersede the use of the log, and may be called the way-meter. This machine, it is proposed, should be made wholly of copper, and it is meant to be placed always so far beneath the water, as that it should never be left dry by the heaving of the vessel. Referring to fig. 1, in the draught, let A denote the container, within which the paddle-wheel is placed, and which should be rendered air-tight in order to prevent the water ever rising above the wheel. It is obvious that the water in the con VOL. XII. tainer (as in a diving-bell) would then only rise to a certain height; and that at no depth at which it would be either convenient or necessary to immerse the way-meter could the water rise higher in the container than it is represented to do in the draught. This being the case, it is apparent (and, moreover, decided by experiments) that the resistance opposed by the water to the paddles at the lower side of the wheel (the only part, for the reasons stated, that could be immerged) would cause it to revolve upon its axis as often as the ship passed through a space equal to thrice its diameter, or thereabouts. This motion being communicated by 2 E 418 66 THE PORTABLE TRIGONOMETRY." the rod C to an index-finger on the dial-plate Di (and which index might be made to circulate as slowly as should be deemed convenient for observation), the course of the ship may be easily and accurately measured, and, if required, even registered in the observer's absence: and as the most violent agitation of the sea would have but little, if any, effect on the water in the submerged container, there is no doubt the proposed machine will be found not only to answer the purpose much better than, but have many advantages over, the log. S, fig. 1, refers to an air-collar, to prevent the air escaping, and within which the rod works. E indicates two wash-boards, which it is intended should be carried below the paddles of the wheel to hinder any side-swell from disturbing the wheel, or affecting it from that quarter; the two ends, of course, to be left open. Fig. 2, shows the ship's way-meter as it will appear when closed up. Fig. 3, exhibits the end of the waymeter, and which ought to be formed with a sharp or dagger point, as cal culated to offer the least resistance to the ship's course. It is not considered necessary to? give any directions as to the size of the machine (which need not be large in any case), the effect of the machine in no respect depending upon its bulk, but in this regard is to be wholly regulated by that of the ship, to which it is meant to be affixed. Neither is it thought needful to make any observations on the subject of the bevelwheels, as the slightest inspection of the draught must render that matter clear. There seems also as little occasion to attempt to point out any, precise spot for fixing the way-meter; it will be enough to say it ought to be placed sufficiently forward on the vessel's side, in order to prevent its motion being checked by the ship's back-water. London. די al -dig ade Had this table been correct, should long ago have sent it to you, conceiving it to be constructed on a useful principle, which, until the appearance of your No. 320, I never saw recommended for practical pur poses. As your Edinburgh correspondent, appears desirous of withdrawing as much as possible of the merit due to P. M. W. to attach it to Professor Leslie, allow me to step in to inquire whether the Professor has more right than myself to priority in the formal tion of such a table? Perhaps it would not be right to 93 |