Page:Popular Science Monthly Volume 36.djvu/546

530 to hair-felt as a non-conductor. By preventing radiation of heat from steam and hot-air pipes, this felt effects a large saving in fuel and gives dry steam at long distances from the boiler, and, by preventing excessive warmth of the boiler-house, adds much to the comfort of the workmen. The felt also finds application as a sheathing for covering wood-work in positions exposed to heat, and for fire-proofing flooring, shelving, partitions, and the like.

As far back as 1850 the Chevalier Aldini of Milan, experimented with asbestus, mainly with the object of turning it to account in the manufacture of asbestus cloth, but little success was met with until twenty years later. The unctuous character of the substance and the extreme fineness of the ultimate fiber are obstacles in the way of making asbestus cloth that shall be strongly coherent and not pull asunder easily. These difficulties appear to have been overcome to a great extent, and now in the form of woven fabrics there are many important applications of asbestus. To one of these, in particular, the attention of the public is frequently directed, because of the numerous fatal fires reported in theatres, music-halls, and similar places of entertainment. In the great majority of theatre fires the flames begin in the stage curtains or drapery. When these are made of asbestus, of course they are incombustible; or, if the curtain alone be of asbestus it affords a means of separating the stage from the body of the theatre, and, in case of fire in the former, prevents its spread to the auditorium. Asbestus curtains are now in use in the principal Roman theatres, and in many theatres in German, English, and American cities, much to the advantage of the theatre-going public. The mineral is also made into gloves, stockings, and other garments; in fact, complete suits of asbestus clothing can be obtained. In Paris the firemen of the city have recently been furnished with entire suits of asbestus cloth, and it is said to be probable that London will soon follow the example of the French capital.

In the form of gloves it is of much service to stokers and furnace-men, and as salvage blankets it is of great value. It is announced that mail-bags will, in the near future, be of asbestus. The frequent loss of mail matter by fire, in connection with railway accidents, renders it desirable that some incombustible material be used for this purpose.

Much of the lower grade of asbestus is ground up with other materials and made into cement and paint. The former is extensively used as a non-conducting covering for boilers and steam-pipes. Being a cement, it can not be readily removed without much labor and loss, so that it is somewhat less convenient than the felt, which, as already mentioned, is used for the same