"The thing is very simple; we must reduce this enormous quantity of powder, while preserving to it its mechanical power."
"Good; but by what means?"
"I am going to tell you," replied Barbicane quietly. "Nothing is more easy than to reduce this mass to one quarter of its bulk. You know that curious cellular matter which constitutes the elementary tissues of vegetables? This substance is found quite pure in many bodies, especially in cotton, which is nothing more than the down of the seeds of the cotton plant. Now cotton, combined with cold nitric acid, becomes transformed into a substance eminently insoluble, combustible, and explosive. It was first discovered in 1832, by Braconnot, a French chemist, who called it xyloidine. In 1838 another Frenchman, Pelouze, investigated its different properties, and finally, in 1846, Schonbein, Professor of Chemistry at Bâle, proposed its employment for purposes of war. This powder, now called pyroxyle, or fulminating cotton, is prepared with great facility by simply plunging cotton for fifteen minutes in nitric acid, then washing it in water, then drying it, and it is ready for use."
"Nothing could be more simple," said Morgan.
"Moreover, pyroxyle is unaltered by moisture—a valuable property to us, inasmuch as it would take several days to charge the cannon. It ignites at 170 degrees in place of 240, and its combustion is so rapid that one may set light to it on the top of ordinary powder, without the latter having time to ignite."
"Perfect!" exclaimed the major.
"Only it is more expensive."
"What matter?" cried J. T. Maston.
"Finally, it imparts to projectiles a velocity four times superior to that of gunpowder. I will even add, that if we mix with it one-eighth of its own weight of nitrate of potass, its expansive force is again considerably augmented."
"Will that be necessary?" asked the major.