ion made by
the three colleagues.

It was at last broken by President Barbicane.

"My brave comrades," said he in a quiet tone, "I start from this
principle, that the resistance of our cannon, in the given conditions,
is unlimited. I shall, therefore, surprise the Honourable J.T. Maston
when I tell him that he has been timid in his calculations, and I
propose to double his 800,000 lbs. of powder."

"Sixteen hundred thousand pounds!" shouted J.T. Maston, jumping out of
his chair.

"Quite as much as that."

"Then we shall have to come back to my cannon half a mile long."

"It is evident," said the major.

"Sixteen hundred thousand pounds of powder," resumed the Secretary of
Committee, "will occupy about a space of 22,000 cubic feet; now, as your
cannon will only hold about 54,000 cubic feet, it will be half full, and
the chamber will not be long enough to allow the explosion of the gas to
give sufficient impulsion to your projectile."

There was nothing to answer. J.T. Maston spoke the truth. They all
looked at Barbicane.

"However," resumed the president, "I hold to that quantity of powder.
Think! 1,600,000 pounds of powder will give 6,000,000,000 litres of
gas."

"Then how is it to be done?" asked the general.

"It is very simple. We must reduce this enormous quantity of powder,
keeping at the same time its mechanical power."

"Good! By what means?"

"I will tell you," answered Barbicane simply.

His interlocutors all looked at him.

"Nothing is easier, in fact," he resumed, "than to bring that mass of
powder to a volume four times less. You all know that curious cellular
matter which constitutes the elementary tissues of vegetables?"

"Ah!" said the major, "I understand you, Barbicane."

"This matter," said the president, "is obtained in perfect purity in
different things, especially in cotton, which is nothing but the skin of
the seeds of the cotton plant. Now cotton, combined with cold nitric
acid, is transformed into a substance eminently insoluble, eminently
combustible, eminently explosive. Some years ago, in 1832, a French
chemist, Braconnot, discovered this substance, which he called
xyloidine. In 1838, another Frenchman, Pelouze, studied its different
properties; and lastly, in 1846, Schonbein, professor of chemistry at
Basle, proposed it as gunpowder. This powder is nitric cotton."

"Or pyroxyle," answered Elphinstone.

"Or fulminating cotton," replied Morgan.

"Is there not an Ameri