At the time when the Crimean War broke out, the attention of many persons was directed to the state of our armaments, and I, like others, fully shared the interest which was excited. The question of elongated projectiles had been previously considered, but we were quite unprepared at that time with rifled ordnance. In thinking over this subject, it occurred to me that it would be possible to give rotation to a projectile, when fired from a smooth-bore gun, by allowing a portion of the powder gas to escape through longitudinal passages formed in the interior, or on the outer surface, of the projectile. If such passages terminated in the direction of a tangent to the circumference of the projectile, the tangential emission of powder gas (under enormous pressure) would act as in a turbine, and produce a rapid rotatory motion of the projectile. It may at first sight appear that such a method would be attended with great loss of power, but it must be remembered that in any system of rifled ordnance enormous energy is required to revolve a heavy projectile, to say nothing of the power lost by the friction of the studs in the rifled grooves.
It was under the impression that my invention would enable all existing smooth-bore guns to be at once utilised for discharging elongated shells and solid projectiles, and would at the same time solve a problem of great national importance, that I applied for and obtained a patent on the 24th November, 1854. It will be evident that this system of giving rotation to elongated projectiles might, in some eases, have rendered it desirable to hoop, or otherwise strengthen, existing guns, or to construct new guns of greater strength than those then in general use. But the main question was: Can rotation be given efficiently without the manifold disadvantages of rifling? As a matter of fact, I submitted my plans to the War Office, and, after some considerable delay, I was informed that the invention was not of a nature to be used, or experimented upon, by the War Department. Our War Department had at that time no artillery that could throw an elongated projectile; yet with that ever-ready tendency of our military authorities to pooh-pooh every proposition of the civil engineer, my scheme was set aside, and so simple and inexpensive an experiment as the manufacture of half a dozen cast-iron elongated projectiles was refused. Nothing more than this was required, as they had plenty of cast-iron guns in store, and all other needful appliances. I, however, was determined to ascertain for myself whether I was right or wrong in my belief that rotation could be effected simply by the emission of a portion of the gases in the manner described, and for this purpose I made a simple cast-iron gun of 5 1/2 in. bore, and of short length. As I had no butt to fire into, I thought it best to use the gun as a mortar, and discharge it into the air at an angle of 45 deg. of elevation; by using small charges I ensured the projectiles falling in my own grounds near Highgate, where I was then living.
The gun was a simple bored cylinder,
cast all in one piece with the framing, which, with its wide base-plate
B,* served for a carriage, as shown in the section in Fig. 33. The
projectiles weighed 60 lb. each, and were turned and truly fitted to
the bore of the gun;
the form of projectile employed is given at D, which is an elevation
showing by dots one of its longitudinal passages with the tangential
aperture at d.* With this simple apparatus I commenced my trials, using
extremely small charges of powder, which I gradually increased until
the projectile reached an estimated altitude of 200 ft., and fell to
earth well within my own grounds. In order to clearly see that the
projectile revolved during flight, I bored on its opposite sides two
holes, 3/4 in. in diameter and 2 in. in depth, in a radial direction,
as shown in section at e e. These holes were tightly rammed with damp
meal powder, and on firing the gun (as I used no wad) the powder became
ignited and fizzed away like a squib. Standing beside the gun I saw the
shot soaring, with its flat end presented to me, and by its rapid
rotation the two squibs formed a sort of revolving Catherine wheel,
which burned until after the shot had fallen to earth, thus proving
beyond all controversy that the projectile both rotated and went end-on
during its whole flight. But still I was no nearer my object, and might
for ever have remained as I was, but for an accidental circumstance
which I will relate.
Some few months after these preliminary experiments were made, I
happened to be one of a house party, staying with Lord James Hay at the
residence of his married daughter, Madame Gudin, in the Rue Balzac,
Paris. Our host gave a farewell dinner to General Hamlin, and a number
of other French officers, who were going to the Crimea. Among the
guests present on that occasion was Prince Napoleon, to whom I was
introduced by my host as the inventor of a new system of firing
elongated projectiles from smooth-bore guns. I happened to have with
me a tiny pocket model, made in mahogany, of one of these new
projectiles, which, in order that it might be more easily understood,
had the passages for the escape of gas formed in its exterior surface,
instead of in the interior, as will be seen from the annexed engraving,
Fig. 34, representing in full size this little model projectile, which
I made more than forty years ago, and which is still in my possession.
Its action was very prettily shown in this way: an upright glass tube
of 1 3/4 in. internal diameter (accurately fitting the shot) had its
lower end stopped up so that it resembled the barrel of a gun. If the model
shot were put into the upper end of this glass tube, when held in a
vertical position, it could not sink down to the bottom without
displacing the air contained in the tube. This air necessarily found an
escape through the external passages; and by the force induced by the
escape of air in the direction of a tangent to the circumference, a
slow and steady rotation of the little mahogany projectile was
observed, as it gradually sank down to the lower end of the glass
tube. Prince Napoleon was very much pleased with the idea, and said
that he was sure that his cousin, the Emperor, would take great
interest in my invention, and that he would get an appointment for me
to show it to him. A few days later, I received a note from Colonel
Belleville requesting my attendance on the following morning at the
Tuileries, where I had a most interesting interview with the Emperor,
who gave me carte blanche to go to Vincennes, and there order to be
made everything that was necessary to fairly test my invention. I,
however, found that it was much more difficult to get what I wanted
made at Vincennes than it would have been at my own works in London,
where other matters required my attention. I consequently sought
another interview with
the Emperor, when I explained this fact to him, and asked permission to
make the projectiles in London, and bring them over. No objection was
raised to this proposal, and as I was about to take my leave the
Emperor said: "In this case you will be put to some expense; I will
have that seen to."
A few days after my return to London, I received a letter from the Due
de Bassano, enclosing an autograph letter from the Emperor, addressed
to Messrs. Baring Bros., Bankers, London, giving me credit for "costs
of manufacturing projectiles," but without naming any sum. Whatever
private instructions there may have been given as a limit to the amount
of credit, none were visible to me; and I could not help forcibly
contrasting this delicate and generous treatment by the Emperor with
the curt refusal of our own military authorities to give my invention
a trial at home.
In a few weeks, the projectiles necessary for the experiments were all
made under my own eye, and packed ready for transport. There were
24-lb. and 30-lb. elongated shots of 4.75 in. in diameter, fitting the
12-pounder smooth-bore French guns, gauges for which had been sent to
me in order to ensure accuracy in size. I had been provided with a
special permit to pass the Customs House at Calais, notwithstanding
which, my passport was rigidly examined, and I was looked at and
questioned by all sorts of officials before I was allowed to proceed
on my journey.
I, as specially directed, went straight on to Vincennes on the
following morning, and was met by Commandant Minié (the inventor of the
rifle which bears that name), who had received instructions to
superintend the experiments and report thereon to the Emperor.
In the large open plain known as the Polygon, at Vincennes, a series of
thin wooden targets had been set up, one behind the other at about 100
metres apart. My projectiles were fired point-blank at these targets,
and generally passed through five or six of them before reaching the
ground, making round holes in each, and showing that all the shots went
end-on. In order to enable us to measure the amount of rotation of the
shots, I had given them a thin hard coating of black Japan varnish,
which was partly scratched off and scored in
lines when passing through the thin planks. There were a few inches of
snow on the ground at the time these experiments were made, and we
could observe the projectiles ricocheting away to the left as a result
of their continued rotation after striking the ground, and sending up
the snow in little jets, thus indicating where they were to be found.
On recovery, the spiral lines scored on the japanned surface in its
passage through the target gave every facility for ascertaining the
angle, and consequently the amount of rotation. It was thus ascertained
that from one and a-half to two and a-quarter rotations had taken place
in the length of the gun, or a greater amount of twist than was usually
given at Woolwich to projectiles of that calibre. Evidence was thus
afforded that the dogmatic way in which the invention had been ignored
by our military authorities was in no way justified. Whatever the real
merits or demerits of my invention may have been, it was at least shown
that, at a time when we had no established rifled system, this early
attempt at a solution of the difficulty had sufficient merit to render
it worthy of a trial.
By the time the experiments were concluded the winter sun had almost
disappeared, and both weary and cold, the several officers, who took
part in the day's trials, and myself walked back to the grim old
fortress of Vincennes, and after threading our way along the cold stone
passages, we found ourselves in the officers' quarters. A bright
blazing fire of logs on the low hearth looked so inviting that we all
instinctively gathered round it, and under the happy influence of a
steaming cup of good mulled claret, there was much noisy talking and
gesticulation. During one of our more quiet intervals, Commandant Minié
remarked that it was quite true that the shot revolved with sufficient
rapidity, and went point forward through the targets; and that, he
said, was very satisfactory as far as it went. But he entirely
mistrusted their present guns, and he did not consider it safe in
practice to fire a 30-lb. shot from a 12-pounder cast-iron gun. The
real question, he said, was; Could any guns be made to stand such
heavy projectiles? This simple observation was the spark which has
kindled one of the greatest industrial revolutions that the present
century has to record, for it instantly forced on my attention the real
difficulty of the situation,
viz.: How were we to make a gun that would be strong enough to throw
with safety these heavy elongated projectiles? I well remember how, on
my lonely journey back to Paris that cold December night, I inwardly
resolved, if possible, to complete the work so satisfactorily begun,
by producing a superior description of cast-iron that would stand the
heavy strains which the increased weight of the projectiles rendered
necessary. At that moment I had no idea whatever in which way I could
attack this new and important problem, but the mere fact that there
was something to discover, something of great importance to achieve,
was sufficient to spur me on. It was indeed to me like the first cry of
the hounds in the hunting field, or the last uncertain miles of the
chase to the eager sportsman. It was a clear run that I had before me
-- a fortune and a name to win -- and only so much time and labour lost
if I failed in the attempt. When, a few days later, I personally
reported to the Emperor the results of the trials at Vincennes, I told
His Majesty that I had made up my mind to study the whole question of
metals suitable for the construction of guns, a proposal which he
encouraged by many kind expressions, and a desire that I should
communicate to him the result of my labours.
My knowledge of iron metallurgy was at that time very limited, and
consisted only of such facts as an engineer must necessarily observe in
the foundry or smith's shop; but this was in one sense an advantage to
me, for I had nothing to unlearn. My mind was open and free to receive
any new impressions, without having to struggle against the bias which
a lifelong practice of routine operations cannot fail more or less to
create.
A little reflection, assisted by a good deal of practical knowledge of
the properties of copper and its several alloys, made me reject all
these from the first, and look to the metal iron, or some of its
combinations, as the only material suitable for heavy ordnance. At
that time nearly all our guns were simply unwrought masses of cast
iron, and it was consequently to the improvement of cast iron that I
first directed my attention.
The experiments at Vincennes took place on or about the 22nd
December, 1854, and before the close of that year I found myself once
more at Baxter House, busy with plans for the production of an improved
metal for the manufacture of guns, which improvement in the quality of
the iron I proposed to effect by the fusion of steel in a bath of
molten pig-iron in a reverberatory furnace. I soon determined on the
form of furnace, and applied for a patent for my "Improvements in the
Manufacture of Iron and Steel," which was dated as early as January
10th, 1855 -- that is, within three weeks after the experiments in the
Polygon at Vincennes.
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