sufficiently astonishing. Who, for instance, could have imagined that a
substance of such comparative specific gravity as crude asbestos could
have been manufactured into a cloth available for aeronautical purposes
in which absence of weight is of such primary importance? Yet here it
appears to be the one thing wanting to give success to that despair of
aeronauts, military ballooning. Many years have now passed away since
scientific military men first turned their attention to this subject;
and it is now long since the War Department of the Government first
authorized experiments to be made with the view of utilising balloons in
warfare, and notwithstanding all the time and money which has been
expended, until now the result in the way of practical success has been
_nil_. No use of balloons was made even in the late Egyptian campaign,
which shows that up to that date English military men had no great faith
in their usefulness or availability.
The difficulties to be encountered are doubtless sufficiently
formidable. Gas, it is clear, could not be carried into a hostile
country or into remote and nearly inaccessible districts. Even if
procurable at all near the battle-field it could only be obtained by a
long and difficult process of generation at the very time when speed and
simplicity would be the main factors of success. Gas, therefore, being
practically out of the question, it seems to have occurred to Mr.
Spencer, the well-known balloon manufacturer, that it would be better
after all to revert to the original conception of Montgolfier. The
old-fashioned fire-ball, which acquired its power of ascension from
rarefied air produced by burning straw or something similar, was, of
course, of far too dangerous a character, and had been productive of far
too many fatal accidents. It remained, therefore, to construct a balloon
of some uninflammable material, in order to obviate this difficulty; and
with the assistance of his friend, Mr. Fisher, the Secretary of the
United Asbestos Company of London, he ultimately succeeded in so doing.
A balloon was accordingly constructed, the whole of the lower part of
which was formed of fine asbestos cloth, and the remainder of canvas,
covered with a fireproof solution. The first trial took place in the
grounds of the Welsh Harp, at Hendon, and this has since been repeated
at Chatham, under the inspection of the Royal Engineers' Committee, and
on both occasions, I am informed, with success. The balloon, which was a
model only, stood about 30 feet high, and was suspended between two
uprights, between which it hung down like a limp rag. It was of a
cylindrical shape, having a deep zone at the equator, and a containing
capacity of about 300 feet. Attached to the neck was a copper
spirit-lamp. As soon as a light was put to the spirit the inflation
commenced, and the balloon was fully distended in a space of about five
minutes.
The immense advantage gained by this method over the tedious and
difficult process of inflation by gas, even under the most favourable
circumstances, is sufficiently obvious, whilst it is at the same time
apparent that the quantity of spirit requisite for an endless number of
ascents could be carried about with the greatest facility. Another
advantage remains to be considered, in that whilst the large volume of
gas required for an ordinary balloon is in itself deleterious, the
rarefied air in the new fireproof balloon is perfectly innocuous, and it
can be raised or lowered at will simply by turning the neck of the lamp
a little up or down. It is perhaps somewhat superfluous to say that the
Russian Government at once adopted these balloons for war purposes.
In further continuance of this part of the subject, that is the
application of asbestos to matters connected with warfare, the
particulars of a very interesting experiment, which may have an
important bearing on the carriage of explosive material in time of war,
was given by Mr. Boyd, the manager of the United Asbestos Company's
works at Harefield, of whom I have already spoken, and to whom I have
been considerably indebted for much practical information, in a paper
read by him before the Society of Arts, on an occasion when, through his
kindness, I had an opportunity of being present. He was referring to the
value of asbestos millboard as a lining for fireproof cases and deed
boxes. The matter, he said, was put to a practical test thus: two iron
rails were supported on brickwork at a height of about eighteen inches
from the ground, and underneath them a strong fire of wood shavings and
chips was made, and when this had well burnt up, a deed box filled with
papers was pushed along the rails to the centre of the fire, where it
was completely enveloped in the flames, and there it remained for a
space of twenty minutes. On the box being withdrawn it unlocked easily,
and the papers were found in perfect preservation, being neither charred
nor discoloured.
On seeing this result, one of the gentlemen present asked if the boxes
could not be used for transporting gunpowder or other explosive
substances. A quarter of a pound of powder was then put in a small bag,
and placed inside a fresh box, which was pushed along the rails into the
centre of the fire, to which fresh fuel had been added. Those present
withdrew to a respectful distance, evidently, said Mr. Boyd, not yet
having absolute faith in the heat-resisting properties of asbestos; and
after the box had been exposed to the fire for twenty minutes the
question naturally arose how it was to be got off again. The manager
himself performed that operation by means of a long iron rod and hook,
after which the box was again opened and the powder found intact. The
question was then asked by some one present who was not yet satisfied,
"Why have the powder in a bag? Let it be laid on the bottom of the box
loose." This was done, and the fire ordeal repeated, again with the same
result. Nothing could well be more interesting or more suggestive to
every one connected with the asbestos industry than the foregoing.
As a final instance of its applicability for purposes connected with
warfare, it may be interesting to mention that I have lately seen it
stated that the fibre would be of great value for use as lint in
hospitals and on the battle-field. Of this I am unable to speak, but if
it be a fact that it can be so used in favourable comparison with the
best lint, as stated, it is certain that its imperishable quality would
be of great advantage, seeing that it could be used over and over again,
only needing to be purified by passing it through fire after each time
of using.
In regard to the use of asbestos in connection with building operations,
much attention is now being given to this in a variety of ways, in
America especially. The building laws of Boston, New York, and
Philadelphia pay special attention to this, and many material
alterations have been required to be made in consequence in the fittings
of several important public buildings, whilst the use of the mineral is,
I believe, rendered compulsory on those wishing to procure licences for
the erection of new theatres, libraries, concert halls, &c. At the
American Academy of Music, in Philadelphia, the underwriters went so far
as to offer a reduction of one per cent. per annum provided an asbestos
curtain was placed in the house. The Fire Apparatus Committee then, it
is reported, succeeded in perfecting "the only barrier of complete
protection to an audience against fire in the world." This curtain, made
of asbestos cloth (97 per cent. pure asbestos and 3 per cent. cotton) is
54 feet wide and 53 feet high. It is hung on wire lines, three-eighths
of an inch thick, connecting with a drum located in the apex of the
roof, and can be raised with ease by two men and lowered by one.
Again, after the disaster at the Ring Strasse Theatre, at Vienna, when
attention was drawn to the great danger arising from the want of some
certain and rapidly applicable means of separating the stage from the
body of the theatre, the Roman Minister of Public Security issued an
order that every theatre should be fitted with a fireproof curtain
capable of entirely isolating the stage from the theatre, and he
indicated an asbestos cloth curtain as one that would meet the case. All
the principal Roman theatres are now supplied with these curtains, the
material having been furnished by the United Asbestos Company of London.
The same company has also recently fitted a similar curtain for use at
the Theatre Royal in Manchester. This is formed of an iron frame holding
the asbestos curtain.
Asbestos fireproof curtains are also in use at the New National
Theatre, Washington; the Criterion, Brooklyn; and in the theatre at
Cleveland, Ohio. They have also lately been supplied to several English
theatres, as well as that at Manchester just mentioned.
The terrible calamity at the Opéra Comique in Paris, coupled with that
which so recently occurred at the burning of the theatre at Exeter,
again set men's minds running in the direction of greater security from
fire in theatres. As a consequence several varieties of curtains, all
involving the use of asbestos, have been contrived. For instance, at the
building of that pretty little theatre (Terry's) in the Strand it was
resolved to replace the usual heavy, cumbrous, slow-lifting iron shield
by a single light-grey asbestos curtain, which moves up and down as
easily as an ordinary window-blind. And the authorities agree that this
is as valuable a protection to the audience as the former ponderous iron
portcullis which, winding slowly up and down, was calculated to depress
the nerves of the audience in the same way that passers-by in the street
are affected by the harsh grating of the iron shop shutters when being
wound down for the night.
Again, in the proposals for a new "Safety Theatre," brought to the
notice of the public by Mr. Henry Irving, stress is naturally laid on
the necessity of sealing the stage, or shutting it off from the
auditorium, so that in the event of fire its perils might be confined to
itself, and to providing an outlet for the smoke, which is often more
disastrous in its effects even than the flames. This he proposed to
accomplish by means of an asbestos curtain which, on being dropped,
would at once become rigid with the wall on either side. This curtain
was proposed to be worked in iron grooves going straight up to the
gridiron floor; and the suggestion was made that this should be used as
constantly as the ordinary act-drop, there being at the same time
nothing to prevent its being made as ornamental as the usual curtain.
It could also be worked as easily, and be just as easily lifted for a
recall. The audience, it was said, would thus have the satisfaction of
knowing that every time the curtain was dropped they were effectually
protected by a fireproof screen, which could be lowered with the same
rapidity as the present curtain.
In continuation of this subject it may be worth mentioning, as showing
the amount of attention which is now being directed to this important
matter, that an experiment was recently made in the neighbourhood of
Oxford Street to test the fire-resisting qualities of another new
curtain for the stage, said to have been invented by Captain Heath. This
experiment took place within a specially built hoarding, within which
there was erected a large model of the Drury Lane stage proscenium.
Captain Heath explained to the company, invited to witness the
experiment, that the curtain was made of asbestos and canvas, and was
rolled on a block of wood placed underneath the front part of the stage,
where it occupied an otherwise useless space, and in no way interfered
with the business of the theatre. The sides of the model were made of
iron plates, and the front entirely of wood. When certain catches were
released counterbalancing weights came into action, and the curtain was
run rapidly up from below. On reaching the top, it pressed tightly and
automatically against the back of the proscenium, turning on at the same
time a supply of water from a perforated pipe which ran along the whole
length of the top of the curtain so as to keep it constantly wet. The
arrangement of the switch used for communicating action to the curtain
was such as to turn on the water and close the curtain against the sides
at will. He also stated that communication with the lever of the switch
could be fitted to any part of the theatre. A very severe fire test was
employed. The model was first filled with inflammable materials such as
shavings and large blocks of wood, over which petroleum was poured. At a
given signal the curtain was raised and the fire lighted. The flames at
once rose, accompanied with volumes of smoke, none of which, however,
found their way to the front of the proscenium. The interior looked like
a furnace. But so effectually were the flames shut off that it was
possible to sit on the fore part of the stage without feeling the heat,
the only thing noticeable being the steam arising from the wet canvas.
This, Captain Heath explained, might be obviated by painting the canvas
in oils. The fire burned fiercely for half an hour, and the universal
opinion of those present was that the curtain was perfectly fireproof,
and that its construction was as simple as it was useful for the purpose
intended.
Whilst these sheets are still in the press, yet another theatre dies the
apparently natural death of all such structures, that is, by fire.
Portugal is this time the scene of the disaster, the sufferer being the
Baquet Theatre in Oporto. The calamity was caused by the wings catching
fire from a gas-jet, whereby the whole of the stage scenery was almost,
immediately afterwards enveloped in flames, the furious progress of
which it was found impossible to arrest. Here, then, was a striking
instance of a holocaust being caused by the want of such a curtain as
has been described; for, had such a thing been available, the stage
would have been at once shut off from the auditorium, and even if it had
not been found possible to save the structure, the fire, at any rate,
would have been localised for a sufficient length of time, to have
enabled the authorities to clear the building, and so have prevented the
panic and horror which ensued, and the fearful sacrifice of life which
humanity now deplores.
It is worth while perhaps recording the foregoing, because there can be
very little doubt that something of this kind will presently be made
compulsory even in England for use in theatres and music halls
generally. And it is believed, from the course matters are now taking in
the United States, that the use of asbestos in some form or other will
be made compulsory there for the shelvings and doors of public libraries
and places for the custody of records, for sheathings between wooden
floorings and below carpets, for hearthstones, for the linings and doors
of elevators or lifts, and for the better preservation of Pullman cars
from fire.
The premises of the American Watch Case Company, of Toronto, have their
floorings protected by an asbestos covering, and I saw an announcement
recently in the _Sherbrooke Gazette_ that this covering had saved their
premises from destruction by a fire which had occurred there. In
connection with this part of the subject it may be added that various
attempts have been made for the introduction of asbestos into the
manufacture of lace curtains, dresses, &c., but I believe that the
principal obstacle in the way of success in this line lies in the fact
that in its present state, in the shape of curtains, for instance, it is
found to be an obstinate holder of dust. This objection will, no doubt,
be presently got rid of; and soon we may hope to have heard the last of
those fearful scenes which have at times occurred from the firing of
ladies' dresses at the footlights in theatres.
The Chevalier Aldini's idea, previously mentioned, has been recently
revived in Paris, the firemen there having been furnished with asbestos
clothes. Immediately after this was done it was reported in the papers
that on a conflagration occurring in the basement of a building there,
the firemen arrived, clad in their asbestos suits, and were thereby
enabled to descend at once into the basement, where they extinguished
the fire in a very short time, and so prevented what might have been a
great calamity. And according to the papers it appears that the same
course is now about to be taken in England, and the London firemen at
any rate protected in a similar manner; and there can be little doubt
that this course will presently be universally adopted for the
protection of the men engaged in saving life and property from
destruction by fire. Nothing has yet been discovered that will equal
asbestos for this purpose. It will neither burn nor smoulder, and is as
impervious to fire as well made mackintosh is to water.
Manufactured into cloth and paper, it is in use in sugar refineries,
chemical laboratories, &c., for straining and other purposes, especially
for filtering acids and similar fluids. A coarser kind of cloth is used
for stokers and furnacemen's aprons, for salvage blankets, and gloves. A
special quality of glove made of asbestos cloth, lined with rubber, is
supplied for electric light work.
A further development of the industry is indicated by the announcement
that a New York manufacturing firm has recently taken over a large
contract for the manufacture of mail bags out of asbestos cloth.
It is also proposed to be used as an inner sole or lining for boots and
shoes with the object of keeping the feet warm in winter and cool in
summer, the material possessing the double advantage of being at once a
preserver of heat and a protector from cold.
For cold storage buildings it will doubtless be found invaluable. There
are buildings in New York, principally for fish preservation, which are
built with double walls surrounding the cold chambers, having some kind
of non-conducting material between the walls by way of lining. For this
purpose asbestos would be unsurpassed, and the cheap No. 3 quality would
answer perfectly well.
Mr. Boyd, in the lecture before referred to, says that some years ago,
when resident at Genoa, he was one of the members of a committee for
procuring a new floating chapel for the use of seamen. The old chapel
was built on the deck of a hulk, but the extremely high summer
temperature caused the repairs to be both frequent and costly. The
committee therefore wanted the new chapel to be built of iron, but were
deterred by the fear that its roof and sides, exposed to the sun, would
get so hot as to render the interior unbearable. He therefore proposed
to fill up the space between the outer skin and the inner boarding with
asbestos ground to a rough powder; and this suggestion was adopted, the
powder being tightly rammed in by the carpenters. The result, he informs
us, was so successful that whilst the outside temperature stood at 100°,
the temperature inside, when doors and windows were kept shut, did not
exceed 70°. And he therefore suggests that asbestos powder might be used
in a similar way for rendering the deck cabins of steamers navigating
the Red Sea and Suez Canal more comfortable for the passengers.
For wall and ornamental papers it is being largely used, and a superior
quality of asbestos writing paper is now being made in Paris. One can
easily imagine a great future in this line for asbestos paper written or
printed on with asbestos ink for all kinds of registers and permanent
records, bankers' and merchants' books, and the like. One of the leading
manufacturers in New York already prints his price lists on asbestos
paper. And another has on show fine papers as susceptible of receiving
good impressions from type as any in use in modern books. Coloured wall
papers also are manufactured in great variety, which are not merely
incombustible, but practically indestructible by fire; and which retain,
even after severe heat tests, their colourings, markings and letterings
as clearly impressed and as vividly visible as before. Boards also are
made of asbestos, varying from the thinnest and lightest card to heavy
shelving, fit either for partitions in safes or for use in large
libraries.
In a recent number of "L'Industrie Moderne" I found an account of a new
process invented by a Mr. Ladewig for manufacturing pulp and paper from
asbestos fibre, which he asserts will not only resist the action of both
fire and water, but will absorb no moisture; this pulp, he says, may be
used as a stuffing and for the joints of engines. He further proposes to
use it in the form of a solid cardboard as a roofing material for light
structures.
The process of manufacture consists in mixing about 25 per cent. of
asbestos fibre with about 25 or 35 per cent. of powdered sulphate of
alumina. This mixture is moistened with an aqueous solution of chloride
of zinc. The mixture is washed with water and then treated with an
aqueous solution of ammoniacal gas. The mixture is again washed and then
treated with a solution composed of one part of resin soap and eight or
ten parts of water mixed with an equal bulk of sulphate of alumina,
which should be us pure as possible. The mixture thus obtained should
have a slightly pulpy consistency. Finally, there is added to it 35 per
cent. of powdered asbestos and 5 to 8 per cent. of white barytes. This
pulp is treated with water in an ordinary paper machine, and worked just
like paper pulp.
In order to manufacture a solid cardboard from asbestos which shall be
proof against fire and water and capable of serving as a roofing
material, sheets of common cardboard, tarred or otherwise prepared, are
covered with the pulp. The application is made in a paper machine, the
pulp being allowed to flow over the cardboard. Among other uses, the
asbestos paper has been recommended for the manufacture of cigarettes,
though its applicability for this purpose is not so readily seen.
Manufactured into paint, the demand for it is continually increasing.
It is used in the Houses of Parliament, as it was in very large
quantities at the several recent exhibitions at South Kensington.
In the form of cement there is nothing equal to it as an efficient
covering for boilers, steam pipes, hotblast furnaces, stills, &c. For
this purpose it is made of about the consistency of mortar and spread on
with a trowel in the ordinary way. Certain chemical ingredients have to
be added, which, while not injurious to the metal, cause the asbestos to
adhere firmly to the plates, so that when dry it becomes quite hard and
can be walked over without being injured. With a boiler carrying say 80
lbs. steam pressure, the application of from 1-½ to 2 inches of this
composition so well retains the heat in the boiler, that a thermometer
with the bulb held close to the outer surface of the covering will not
indicate more than 80° to 85° Fahrenheit. Boilers, steam pipes, &c.,
covered in with this composition will, it is asserted by the
manufacturers, effect a saving of as much as 33 per cent. in fuel.[10]