Pliny is silent the mode of fabricating asbes tine cloth. The chemist of the 9th century directs the al ternate soaking of asbestos in oil and water, in order to render it fit for spinning. Kircher, in the 17th century, affirms, that there were a few persons in his country ac quainted with the mode both of spinning and weaving it, whereof sonic might be seen in his museum ; hut such individuals were very rare, and did so only with the view of great emolument. He considered it a secret art ; adding, that though it had been described by Boetius, Libavins, and Porta, they had been deceived by an erro neous account. Pivati, in his Encyclopmdia, published in the year 1748, says, that a quantity of asbestos was for merly spun at Venice. All these remarks refer to an early date, and they inspired very little confidence. At length, Ciampini, an Italian, entered on a course of expe riments towards the beginning of the 18th century. The method he describes consists in soaking the asbestos in warm water, after which it is opened and divided with the hands, to allow the extraneous particles to escape. This operation being frequently repeated, the flaxy pal ts are collected and laid in a sieve to dry, and then gently card ed, some of tic flaxen substance being allowed to hang over the sides. Next, by mixing the ends of thread with what hangs over of the asbestos, both may be drawn out and twisted together, and wound on a reek Or, instead of carding the substance and then using thread, Ciampini affirms, that the asbestos may be drawn out by mixing it with common hemp. During the operation, the fore finger and thumb must be kept constantly wet with oil, both to protect the skin from the friction of the substance while drawing out in a thread, and to render the filaments more soft and flexible. The thread of asbestos, combined with real flax, having been thus obtained, it may, with great care, be wove into a coarse cloth ; which, being put into the fire, the flaxen portion will be consumed, while the asbestine part remains entire. This cloth can be best pre served by keeping it well oiled ; when committed to the flames, the oil burns off, and the cloth comes out white and purified. Whether or not the art was preserved in Europe, there is every reason to believe that it subsisted in the East. Independent of the Venetian traveller's nar rative, we learn, that a piece of incombustible cloth was transmitted from China to Batavia, and from thence to Eng land, in the year 1634, which is described as a handkerchief or pattern, but it seems to have been a small portion of very coarse cloth. It was subjected to various experi ments, and the result was, its being withdrawn whiter and cleaner after having been rendered red hot in a fire.
A few years ago, the art of making incombustible cloth was completely revived by M. Perpenti, an Italian lady, who has improved on the process of all her predecessors. having seen a distaff of asbestos, from the ruins of Her culaneum, in the cabinet of natural history belonging to the canon Cxsar Gattoni at Coino, she was made acquaint ed by him with the different methods which the ancients are supposed to have adopted in making cloth. On in spection also, she remarked, that their asbestine cloth was fabricated of double threads, in order to be of greater strength. M. Perpenti began by beating the asbestos, and steeping it in oil and in water, whet eby the threads became more pliant ; but finding them too much relaxed for weav ing by the oil, she abandoned this method. She restricted
her operations to softening it in water, drying it in the sun, and then carding it like wool. A very close toothed steel comb was used in carding, as the filaments were thick and short ; and in this nay she succeeded in obtaining a weak and unequal thread, with which nevertheless she was able to make a pair of gloves. Much difference, to he found in the nature of the asbestos itself Ciamputt bad before remarked, that although the asbestos of Cyprus is reputed the best, it in fact proved the woist ; and was most suitable came from Corsica. M Perpenti first used asbestos from the mountains of the valley of MaIrt e() in the VAR-line, which proved to be better than what nab procured from the environs of Genoa. In the former, she vArierved, there were threads much longer than the piece of asbestos containing them ; whence it became im p•rtant to devise some method whereby they should be detached and unravelled. Here also M. Perpenti was successful, for by rubbing the asbestos, and disengaging the two ends of the threads, she thus obtained some of the greatest beauty, and suitable for the most delicate work. These were several feet long, and equilly fine and strong as silk or linen thread. It was the more singular that such should be the case, as a piece of asbestos, to external appearance, exhibits only a mass of thick short threads, winch has always been the chief obstacle to the fabrication of incombustible cloth. All the previous preparation, therefore, which is necessary, is confined to softening the asbestine substance in water, beating it to create greater flexibility, and employing the iron comb. The threads ac quire greater consistence, by moistening the finger with a little oil or gum while they arc spun.
Incombustible paper. Those who have occupied them selves with the subject of incombustible cloth, have also directed their attention to the fabrication of incombustible paper from asbestos. Kircher proposes a certain process for it, which we do not discover he adopted. Some was made of Welsh asbestos towards the close of the seven teenth century; and Ciampini thinks the shorter asbestine threads would answer this purpose. M. Perpenti found the asbestos of Genoa, which was less suitable for spin ning, the best adapted for making paper, which she ac coinplished by washing arid purifying it well. Some time ago, M. Sage exhibited before the French Institute, a leaf of incombustible paper, made twenty years before that pe riod, by NI. Leerier, of Lisle, the proprietor of a paper ma nufactory. It was not smooth like paper fabricated of flax, but had sufficient coherence, and if the ink employed was well gummed, would readily receive writing. When put among burning coals it was not consumed ; it assumed a greyish colour from the glue, and the written characters appeared red. M. Sage regrets that M. Levrier had not received greater encouragement, as deeds on common pa per might be preserved from the flames by inclosure in cases of asbestos; but Ciampini remarks, that it was no pro tection to a stick which he had enveloped in it. According to M. Perpenti's experiments, an indestructible ink may be obtained, by mixing a third of sulphate of iron with two thirds oxide of manganese, the whole being well pulverised.