He was once in New York working upon his torpedoes.
He invited the Mayor and many others to hear him lecture.
They came and were all much interested.
He showed them the copper cylinders which were to hold the powder.
Then he showed them the clockwork, which, when it was set running, would cause the cylinders to explode.
He turned to a case and drew out a peg.
He then said, "Gentlemen, this torpedo is all ready to blow up a vessel.
It contains one hundred and seventy pounds of powder.
The clockwork is now running.
If I should allow it to run fifteen minutes it would blow us all to atoms."