The Sun.
London, England, 1867-08-24 00:00:00

GUN CO7TON.

The recent explosion of gun cotton at Stowmarket
gives rise to sonic controversy as to the exact point
at which that substance explodes. The shootings
season having begun, this is a matter of special hn-
portance, and it may be well that we should state
specifically what the exploding point of the substance
really is. .But first, we must be understood as speak-
ing only of chemical gun cotton, made with the best
acid and pure cellulose. Of the lower types of gun
cotton, of pure fibre, unscientifically treated, or
imperfectly acted upon by nitric and sulphuric acid,
there are infinite varieties ; and all sorts of incorrect
conclusions have been based upon experiments made
with gun cotton falling short, in a greater or less
degree, of absolute chemical purity.
Of the behaviour of gun cotton of this description
when submitted to various artificial temperatures,
we have an elaborate and trustworthy account in
this year's Bakerian lecture, prepared by Professor
Abel for the Royal Society. From the experiments
recorded in this lecture, it appears that " the ave-
rage temperature at which gun cotton explodes
when in a condition most favourable to its rapid
heating is about 150 deg. Centigrade," or 302 deg.
Fahrenheit ; and, according to Schrotter, Redten-
bacher, and Schneider, 136 deg. Centigrade, or 277
deg. Fahrenheit, is the lowest temperature at which
pure gun cotton explodes. It is evident, therefore,
that unless sportsmen select their kitchen ovens as
store cupboards for their gun cotton cartridges they
need be under no uneasiness as to possible acci-
dents from excess of temperature. I-low the acci-
dent at Stowmarket occurred has not yet been
explained; but it is certain that it could by no pos-
sibility have been due to the overheating of the
drying room, any more than an explosion of gun-
powder could be brought about by the same influ-
ences,
anfor no combination of steam and sun heat
would run up the temperature to the height at which
alone
explosion can take place. The very diffe-
rent behaviour of gun cotton and gunpowder under
explosion, as illustrated by this accident and by
another which,
curiously enough, occurred a few
days afterwards in a
will not have escapedgnuontpicoew. dle,r
hme
cilolnattraFstawveasrshmaomst,
remarkable. At Faversham two men were killed and
two others were severely injured, and the damage
done was as considerable as generally results from
an explosion of gunpowder. At Stowmarket, al-
though a large quantity of cotton was consumed, it
was little more than a sudden puff of flame, and not
a pane of glass in buildings only ten yards distant
was broken. In fact, there was no explosion at all,
in the ordinary sense of the word. This is due prin-
cipally to the fact that in the case of gun cotton you
must have some material resistance if you want to
derive any effects; where there is no such resistance
the substance is comparatively innocuous. You
must, as it has been expressed, cheat the gun cotton
into the belief that it has got something to do before
it will exert itself to do it. A familiar inStant2e of
this is afforded by the experiment of exploding 8,
small quantity of gunpowder in one, dish of a
pair of scales. The explosicAl will depress the
scale with violence, „lila if the experiment be
repeated with gun cotton no moVenient of
the scales will take place. A corresponding
effect is noticeable ha the almost complete absence
of recoil when gun cotton charges are used, which is
generally attributable 'to the absence of solid residue
from fired gun cotton, to which cause also it is due
that a turf of good gun cotton may be fired tm the
palm of the naked hand without inttnVonience.
It is, however, no part of our present intention to
discuss the many interesting properties of gun cotton.
We have referred to them before on more than one
occasion ; but as the of September is at hand, it
is right that ar.s; shadow which the late accident
may hay,-,s thrown over the prospeQc of gtin cotton
should be dispelled, and it tidy not be unseasonable
to remind spottBMen that they have now an oppor-
tunity of trying the substance, and arriving at some
practical estimate of its value, under more favour-
able conditions than have before occurred. A year
ago we recommended them "to pause at least
another season before venturing to make use of
gun cotton," and we wrote this in the interests of
the material, the use of which has so often been re-
tarded by injurious attempts to force it prematurely
into public notice. But another season has now
arrived, and the substance is now presented in a
form which justifies its experimental application.
Safe, impermeable gun-cotton cartridges for shot
guns may now be purchased ; and the absence of
smoke, of fouling, of recoil, and of heating effects
upon the gun, is a point in favour of the substance
which cannot fail sooner or later to overcome the
prejudice which, without reason, has hitherto
operated against its emploympt--Pall-Mall
Gazette,

R ailways.

I Closing I Business
Fries. done.

-i3O B 2
112 114
35 15

3 5
55 63
70 72

109 111
30 30;
4 6

115 117
Iy6 117

VG IS
41i

25 30
28 3,1

.27

19 50
17 18
10 15
116 117
82
46 18
'25 1t,!4

301 f

J5l 93 5

127 1