4-15-1913.
Same still used as in Test No. 1, thirty pounds of a clean, good grade
Granulated Cork, of a fineness to pass a 1/16″ mesh, was put into the
still—this half filling same.
Steam turned on at 70 pounds and run for one hour.
Tests made at A. J. Crombie & Co., Brooklyn, N. Y.
* * * * *
Anderson, Ure, Chevruel, Fownes, Watts, Brisbane, men of science; to
these we are indebted for the little that is known of corkwood, and
although perhaps much more could be said by elaboration, it will suffice
to record the facts in this monograph for the purpose involved.
But to the data assembled may be added much in commentation, for the
material becomes more interesting the more it is studied, and most
naturally excites comparison with other materials and substitutes, as
well as calling forth a discussion as to the dangers involved by its
presence in the places where, by skill of hand and machinery, it is
transformed into the many commercial forms, noted in this article. We
comment upon its growth, which is truly wonderful and all-absorbing in
its many interesting phases; it takes us to the romance of the East and
the enchantment of the Moorish occupation; through which these forests
of cork-producing trees passed and yet remain to furnish the present
generation. We comment upon its lightness and buoyancy, due to the
presence of air and excess of hydrogen, known to be lighter than air;
and the small percentage of other matter which, being of less
importance, make its other quality so renowned as to make it the most
wonderful growth of its kind. Its imperviousness to water and other
liquids have given us moments of reflection, upon this phenomenon, but
now known to be because of the cellulose composing the cell walls and
which, when the substance is under compression, practically is all that
remains, except for the small quantity of resin, etc., to resist the
passage of liquids or gases. But heretofore when these commentations
have reached the burning point, its physical nature was entirely
eliminated from the conjecturing and the important part neglected, that
as the cork contained fifty-three per cent of air, heat of 450 degrees
expands to the point of explosion, the contents of those cells nearest
the surface, which giving up their oxygen feed the flames and in their
passage help to disintegrate the cell walls and make them more easily
ignited. Thus causing a rapid burning, flash fire which, in its fury,
Pluto could not rival, only racing over the surface of the cork, burning
but slightly, yet helped by other conditions, resulting in a fire
destructive and fierce. This rapid burning leaves the outer surface of
the cork charred and flaky and causes a discoloration beneath it
attributed to the dissolving of the resins, etc. Of course where there
is a large quantity of corkwood the extent of the burning must
necessarily be greater and the depth of the char increased. But it
appears that the first flash burning produces a sort of protection coat
of carbon around the remaining unburned portions which a subsequent
flame penetrates with difficulty.[28]
[28] In the making of insulation material, the carbonization of the
cork is accomplished without destruction of fibre and stands a
high flame test.
A simple experiment to show this depth of burning, and one that is easy
to do, is the flash and flame test which was found of interest.
Two pieces of cork were taken, having the following measurements—8/16″
× 7/16″ × 11/16″—and the first piece held so that the flame of a gas
jet would cause a flash over its surface; then the second piece is taken
and held within the flame for a minute.
It will be found that the corkwood has expanded and the dimensions
increased to the following:
Flash Flame
8/16″ × 13/16″ × 11/16″ 10/16″ × 14/16″ × 11/16″
showing the effects of the heat upon the tissue and contents of the
cells.
Now in scraping these samples clean of all char the dimensions will
return to the following:
Flash Flame
6/16″ × 11/16″ × 11/16″ 8/16″ × 10/16″ × 11/16″
clearly setting forth the fact that the char is comparatively light in
both cases, ranging from 1/8″ to 1/4″.
To this cause is ascribed the burnability of cork having by careful
observation and experiment, extending over a period of two years,
studied the results of numerous fires in premises where cork was being
worked and also conducted heat applications on various grades of
cork[29] resulting in the foregoing findings.[30] Thus it is found that
cork contains sufficient air to supply any fire in it and precludes the
necessity of free access to any outside supply which makes it a material
worthy to be watched. To its many qualities of great service to man,
giving him a material which from the ages past, till now, has proven of
such value, must be added this one, no less important than others, which
heretofore have been its commendable features.
[29] Using ordinary glass (armoured) thermometer for ascertaining
degrees.
[30] One thousand degrees Fahrenheit, causing no greater combustion
than the lower degree, other than the increased burning of
remaining substance after the flash, due to the higher
temperature.
Rather than attend the “cork” through the many passages of commerce and
manufacture, it is deemed propitious to deviate a little from a natural
course, i.e., from the growing to manufacture and rather advance to a
knowledge of the many uses to which this material is put and its
application to the innumerable arts, and then take up the manufacture.