Page:Popular Science Monthly Volume 30.djvu/884

860 by itself, or after the addition of gelatin or other appropriate cultivating matter, consumes oxygen from the dissolved air at lower temperatures, but does not consume any after heating to 60° C. for three hours, may be regarded as having contained living organisms, but not of a kind able to survive exposures to that temperature; and a water which, by itself or after the addition of gelatin or the like, continues to consume oxygen from its contained air after the water has been heated to 60° C, is to be regarded as containing spores or germs of organisms that can survive that temperature. Whether the power of resisting a given temperature affords any clew to the innocence or malignity of an organism is a question for future biologists, and must be decided by separate observations on each known species.

Amianthus—Amianthus is a mineral consisting of a double silicate of hydrate of lime and magnesia with a little oxide of iron or alumina. It generally occurs in the form of silky fibers, sometimes nacreous and having a greasy feeling, qualities that give it a kind of organic aspect. It is incombustible and infusible. It appears to burn in the fire, but when it is withdrawn from the flames it immediately returns to its natural condition without having undergone any alteration. This property seems to have been known from very early times. The ancients are said to have used it for winding-sheets for the bodies they placed upon the funeral-pyres, the cloths made of it holding the ashes of the dead separate from those of the fuel. Whether this be so or not, the secret was lost, and amianthus was, till quite recently, nothing but a natural curiosity. The art is now practiced of introducing amianthus into woven goods and of making with it a considerable number of incombustible objects, such as gloves, garments, and safety-ropes. It has also been introduced into paints and protective coverings for wood. As it is a poor conductor of heat, is not attacked by acids, and does not act on metals, it makes a good envelope, and has been found excellently adapted to application at the joints of steam-pipes. The manufacture of amianthus is carried on by an English company formed by the amalgamation of three rival Anglo-Italian companies, which has control of the most important beds of asbestus known, particularly of those in England, Italy, Corsica, and Canada. The Italian asbestus is most sought after, on account of the length, fineness, softness, and flexibility of its fibers. The fibers of the mineral of other countries are shorter, harsher, and less easily separated, and, therefore, inferior. The fibers, the mineral having been passed through a rolling-mill, are stirred in a bath of hot water till they become very supple. The longer fibers are then taken out, washed, and sorted into packages of uniform length, to be spun into threads and woven into cloths, for garments of various kinds, or into cords. The shorter fibers are beaten into a powder, and then mixed with linseed-oil into a pulp very like paper-pulp, to which India-rubber is added to give elasticity; and this makes an excellent paint for protection against heat, particularly suitable for application to steam-conductors, boilers, joints, furnishing of every kind, and wood.

A River made a Nuisance.—The "Lancet" records the failure of the system which has been applied, with great expense, for disposing of the sewage of London by turning it into the lower part of the Thames. It declares it the greatest nuisance of England, and charges it with having made the Thames a cesspool throughout its tidal region. "Of the existence of a tremendous nuisance," it says, "and of the urgent danger to which it exposes the metropolis, there is no longer any room for doubt. Hard as the Metropolitan Board of Works fought, they were utterly crushed by the evidence brought before the late Royal Commission, and by he stinging words of the commissioners in their reports. They have, indeed, practically admitted the whole case against them by adopting a costly system of disinfection which could only be justified by urgent necessity. The disinfection, it is true, is a sham, utterly useless, and a gigantic waste of the money of the rate-payers; but it is none the less a confession of the existence of a nuisance created by the board, and for many years defended by them as a public blessing."