History

In the course of 1833, a well known French chemist, Braconnot, having dissolved starch and some other organic matters in nitric acid, obtained by precipitating the dissolution by water, a new substance that he called Xyloidine. This substance was remarkable for its quick inflammability, but it did not fulminate with as much energy as gun cotton, and it left a residue of charcoal.

Five years after the publication of the re-searches of Braconnot, Mr. Pelouze, in an interesting paper, announced the discovery of a more simple and economical process to obtain the Xyloidine. This process consisted in substituting for the dissolution of the starch, the pure and simply impregnation of the paper, cotton, flax, etc. by concentrated nitric acid. Besides, Mr. Pelouze announced to the Academy of Sciences, that Xyloidine resulted from the union of the elements of nitric acid with those of starch, and explained by this decomposition, the excessive combustibility that he found in this substance.

We shall see, hereafter, if it was really the Xyloidine of Braconnot that Pelouze obtained.

For eight years the researches of the abovo chemists seem to have been forgotten, when in September, 1846, a great stir was made concerning a new discovery of Mr. Schoenbein, a Swiss chemist, who announced the transformation of the cotton into an explosive substance of a power superior to that of ordinary powder. Mr. Dumas was informed of this invention by a letter from the author, who appeared anxious to keep his process secret. But the opinion of Mr. Dumas was, that this invention was connected, without doubt, with the history of the Xyloidine of Braconnot and Pelouze. From that time, chemists made extensive researches upon this subject. Different recipes for preparing the fulminating cotton or gun cotton were published in Germany. In October of the same year, Mr. Dumas communicated to the Academy of Sciences the processes of Messrs. Otto, Dr. Knopp, Dr. Bley, etc. It resulted from the experiment of those chemists, that fuming nitric acid had the property of rendering explosive not only cotton, but also shavings and sawdust.

As we see, the German recipes were nothing more than Pelouze's process to prepare the Xyloidine. This latter chemist had only to prepare cotton and paper, as he had done eight years before, and introduce 1 1/2 grain of this matter into a pistol, to obtain an explosive effect, such, that a board 9 inches thick was pierced by a bullet, at a distance of 76 feet. Other essays made by MM. Prelat, Sequier, Lassaigne, etc., with different fire-arms, have left no doubt on the ballistic properties of the nitric paper.

Two important questions were to be resolved, one purely scientific, the other practical. Was the explosive product obtained by Pelouze and the German chemists, the Xyloidine of Bracon-not? Was this product susceptible of being substituted for the ordinary powder?

Nobody had thought to put the first question, and Messrs. Flores Demonte, and Menard seem to be the first who have considered the difference between the Xyloidine of Braconnot and the cellulose treated by nitric acid. As for Mr. Pelouze, who, with several other chemists, had not suspected the difference between the two products, he soon ascertained that ligneous substances take a larger quantity of nitric acid than starch; and he declared a short time after that the products were different in their properties and composition; that is the reason why this chemist proposed to call pyroxyle or pyroxyline the product of the action of nitric acid on cotton, paper, and other ligneous mat-ter. He demonstrated in the following terms the difference between this product and the Xyloidine of Braconnot, obtained by precipitating with water the nitric dissolution of starch and ligneous matters: -

"The Xyloidine," says Mr. Pelouze, "is very soluble in nitric acid, and this dissolution is destroyed in twelve hours, the substance of Braconnot being then transformed into a deliquescent acid."

"The pyroxyline is insoluble even in an excess of nitric acid; it can remain in for several days without disappearing, and without losing any of its weight. The Xyloidine, while very inflammable and detonating by a shock, leaves, when heated in a retort, a residue of charcoal."

"The pyroxyline, heated at 847° to 366°, burns with violence, and its distillation in a retort is impossible."

"The Xyloidine has been analyzed with oxide of copper, as other organic substances, only the quantity of oxide of copper was increased."

"Pyroxyline, in the same circumstances, bursts all the tubes, even by operating on very small quantities."

Such are the properties. As for the composition of the two substances, Mr. Pelouze adds: "I have concluded from my analysis, that the Xyloidine can be represented by one equivalent of starch, which has lost one equivalent of water, and gained one equivalent of nitric acid."

To obtain the formula of the pyroxyline, Mr. Pelouze has chosen a specimen of cotton and paper, leaving very little ashes by incineration, He dried them at 248°, and submitted them to the action of the mono-hydratcd nitric acid, or a mixture of this acid and concentrated sulphuric acid.

In ten experiments, which have lasted from 10 minutes to 48 hours, the increase in weight has been the same, and ranges between 68 and 70 per cent of the dry matter.

Admitting that the nitrio cellulose is the only product which results from the pre-ceding reaction, the calcul indicates that it ought to result from the combination of two equivalents of monohydrated nitric acid, with one equivalent of cellulose, less one equivalent of water; and it has for its formula

C12H9092N06HO or without hypothesis

Cl2H41Oi2N2 The composition corresponds to the following numbers: -

The formula of the Xyloidine, deduced from the analysis, gives the following numbers: -

From the above, obtained, if not by direct analysis, at least by indirect means apparently unexceptionable, it results that when the amylaceous and ligneous matters lose their solid state, and pass, one at the ordinary temperature, the other at a higher temperature, in dissolution in concentrated nitric acid, the compound or compounds which result from the action of water in such dissolutions, essentially differ from the composition and properties of those which result from a simple impregnation of the cellulose.

Since the researches of Mr. Pelouze, the chemical study of pyroxyline has made great progress. Messrs. Fordos and Gelis, in the combustion of pyroxyline, have announced the formation of bi-oxide of nitrogen and a cyauic compound. Mr. Dumas, in a learned paper, has announced the formation of several other products. He speaks thus: "Until now, the analysis of the fulminating cotton has not been made, some are engaged on it, and may be exposed to useless dangers. This analysis is easily made by using the apparatus of Messrs. Gay Lussac and Thenard, which they employed fifty years ago."

"The combustion tube, being heated by an alcohol lamp, at from 392 to 572°, little parcels of gun cotton thrown into it burn quickly without any danger.

"It disengaged vapor of water, carbonic acid, oxide of carbon, nitrous vapors in large quantities, and bioxide of nitrogen. The raw gas contains enough inflammable products to burn when a candle is near by. The color of the flame indicates compounds of the cyanogen." It is in this paper that Mr. Dumas has indicated the way to obtain a fulminating product with chlorate of potash. Cotton impregnated with this salt gives a fulminating product superior to the nitric cotton.

On the occasion of the reading of this paper, Mr. Pelouze differed from Mr. Dumas, in regard to the effects that the gaseous products produce on fire-arms, of which we shall speak hereafter.

This historical notice is sufficient for the present, only we shall state some facts announced by Messrs. Peligot and Pouillet. They have made many experiments on the products of the combustion of gun cotton placed in the same conditions as gun powder.

Mr. Peligot has analyzed gun cotton, dried in vacuum, at the ordinary temperature, and found the following results.

Thus, by representing by

C12HI00IO the composition of the cotton, we see that in contact with nitric acid, it lost one equivalent of water, and takes three equivalents of nitric acid.