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.