Asbestos charecteristics

So little, indeed, is it
affected by the dissolving influences of time that the action of
unnumbered centuries, by which the hardest rocks known to
geologists are worn away, has had no perceptible effect on the
asbestos found embedded in them. Whilst the greater portion
of its bulk is composed of the roughest and most gritty mate-
rials known, it is really as smooth to the touch as soap or oil.
Apparently as combustible as tow, the fiercest heat cannot
consume it, and no combination of acids will affect the appear-
ance and strength of its fibre, even after days of exposure to
its action.*

Its peculiar properties thus endow it with practical inde-
structibility, and enable it to resist decay and destruction
under almost every condition of heat and moisture, even pre-
serving it from undergoing any deleterious change when
brought into contact with superheated steam or grease ; nor
is it even worn away or rendered useless by the severe treat-
ment it undergoes in connection with marine, hydraulic, or
other engines. So little influence of a chemical nature does it
exert over any metal with which it is brought in contact that,
if a joint be broken, the surfaces will be found entirely free
from corrosion. Its incombustible nature and slow conduction
of heat render it also a complete protection from flames. In
its crude state, therefore, it is keenly sought for, whilst, as a
manufactured article, it must necessarily command a high price
until more extensive sources of supplj' than those at present
available are discovered.

The most important characteiistic of asbestos is its fireproof
quality, which was well-known to and appreciated by the
ancients. In our own time it is also known as a useful non-
Growth, the addition of homogeneons body substance, is absolutely
universal. The inorganic crystal grows by absorbing homogeneous
matter from the surrounding fluid medium, which then passes from a
fluid into a solid condition. The only difference between the growth of a
crystal and that of the simplest organic individual, the cell, is that the
former adds the new substance externally, while the latter absorbs it
internally.

History,AND PHYSICAL AND CHEMICAL PROPETIES OF ASBESTOS

The use of asbestos can be traced back to ancient times. The Romans
drew their supplies from the Italian Alps, and even from the Ural. They
imagined it to be of vegetable origin : the highly silky appearance and unctuous
feel giving them the impression that it was an organic substance.

It is said that cremation cloth, in which dead bodies were enwrapped to be
consumed by fire, was made of asbestos. It appears, however, that the high cost
of making this asbestos cloth militated against its general use. Pliny refers to
It as a rare and costly cloth — ' linum vivum^ — ' the funeral dress of kings ' he
calls it : evidently assuming that it was of vegetable origin. The fibre used
came from the Italian Alps and was called ' amianthus.' It was apparently very
difiicult to spin, on account of its shortness; but judging from a piece of asbestos
cloth on exhibition in the Vatican, and which is said to have originated in the
days of ancient Rome, it is certain that vegetable fibre was intermixed with the
real asbestos fibre in the making of so-called asbestos cloths. There is, moreover,
according to Sir E. J. Smith, in the library of the Vatican, a winding sheet of
Italian asbestos, which, although very coarsely made, is of a very soft and silky
texture. This piece of cloth— perfectly preserved — was, together with some ashes,
found in a sarcophagus in the Via Praenestina in 1702. It was subsequently
placed in the Vatican Library by order of Clement XL It appears that some
vegetable fibre was used with real asbestos fibre in the making of the cloth;
because it is reported that, when fire was applied at one end of the cloth, it
burned with brightness, but leaving the real mineral fibre intact.