Since the discovery of pyroxylic products, the question relative to the fabrication of caps can bo considered in a new aspect.

Will it not be possible to supersede the use of the fulminate of mercury in the fabrication of caps?

If the facts are not numerous yet, and if the experiment is not sufficient enough to answer this question, the experiments of Mr. Pelouze deserve great attention.

At a meeting of the Academic des Sciences, this savant speaks thus: -

"If we put a small quantity of nitric paper or gun cotton on an anvil, and strike it with a hammer, a detonation is heard; a great part of the matter has not been burned, and to have a complete inflammation the percussion must be repeated several times. The same thing occurs when the pyroxyline is introduced into a cap and tried in a gun. The greater part of the substance is not destroyed, and obstructs the chimney. The inflammation thus stopped is rarely communicated to the powder, principally when it is ordinary powder.

"It is probable that by modifying the chimney this defect could be avoided, and it could be possible to overcome the disadvantages connected with the pyroxyline in the stage of disaggregation in which it is found in the cotton or paper. In either case this matter was used alone to prepare percussion powder. By substituting for the paper or cotton the pyroxyline prepared with very fine tissues of hemp, linen, and introducing these substances into the caps, a detonation as strong as with the fulminate of mercury is produced."

The opinion of Mr. Pelouze was not adopted by every chemist, and Mr. Dumas again called attention to the fact that the pyroxyline by burning in the open air gives nitrous vapors. He observed that this powder used in the percussion powder will inevitably form nitrous acid; and he was disposed to believe that fire- arms cannot resist, that they will be quickly oxidized if the fire is communicated by the py-roxyline.

Mr. Pelouze made some new experiments. He studied the action of the new powder on firearms, and his essays were repeated by several manufacturers, and a gunsmith, and the result was shown to be that the pyroxyline has no more destructive action than the fulminate of mercury and the nitre, and this result, says Mr. Pelouze, has nothing extraordinary. Why nitrous vapors, by supposing some formed during the combustion of the pyroxyline, which is doubtful, bo more destructive to firearms than the sulphuret of potassium, the formation of which in barrels and chimney is consistent with ordinary powder? A priori it is more logical that the presence of an adhering solid body ought to be more noxious than a gas.

Mr. Pelouze maintains that the differencc established by Mr, Dumas between the combustion in the barrel of a gun and that of the cap could not exist.

New experiments, confirming those of Mr. Pelouze, have demonstrated that if gun cotton, used alone as percussion powder, has badly succeeded, this cotton pressed with a few grains of ordinary powder in new caps answers very well; that the powder determines the combustion of the totality of the pyroxylinc, and the inflammation is communicated easily to the charge. Charcoal and sulphur associated with the pyroxylino have given very good results.

Mr. Vrij, professor of chemistry at Amsterdam, has ascertained that starch treated by mono-hydra ted nitric acid, swells, and is transformed into xyloidine. As pyroxyline is soluble in monohydrated nitric acid, if concentrated sulphuric acid is added to this solution, all the pyroxylino is precipitated into a white powder, which has all the primitive properties except the form. The question which has not been answered yet, is, whether this powder can be utilized in the preparation of percussion powder.

More could be said on this subject, but we think it of no use to do so in advance of actual experiment. A time will come, we have no doubt, at which this product will take the place of metallic fulminates.