tant difference between a _directrix_ and
an _axis_," hotly observed Barbican.

"I know what an _abscissa_ is, any how!" cried the Captain. "Can you say
as much?"

"Did you ever understand what is meant by a _double ordinate_?" asked
Barbican, trying to keep cool.

"More than you ever did about a _transverse_ and a _conjugate!_" replied
the Captain, with much asperity.

"Any one not convinced at a glance that this _eccentricity_ is equal to
_unity_, must be blind as a bat!" exclaimed Barbican, fast losing his
ordinary urbanity.

"_Less_ than _unity_, you mean! If you want spectacles, here are mine!"
shouted the Captain, angrily tearing them off and offering them to his
adversary.

"Dear boys!" interposed Ardan--

--"The _eccentricity_ is _equal_ to _unity_!" cried Barbican.

--"The _eccentricity_ is _less_ than _unity_!" screamed M'Nicholl.

"Talking of eccentricity--" put in Ardan.

--"Therefore it's a _parabola_, and must be!" cried Barbican,
triumphantly.

--"Therefore it's _hyperbola_ and nothing shorter!" was the Captain's
quite as confident reply.

"For gracious sake!--" resumed Ardan.

"Then produce your _asymptote_!" exclaimed Barbican, with an angry
sneer.

"Let us see the _symmetrical point_!" roared the Captain, quite
savagely.

"Dear boys! old fellows!--" cried Ardan, as loud as his lungs would let
him.

"It's useless to argue with a Mississippi steamboat Captain," ejaculated
Barbican; "he never gives in till he blows up!"

"Never try to convince a Yankee schoolmaster," replied M'Nicholl; "he
has one book by heart and don't believe in any other!"

"Here, friend Michael, get me a cord, won't you? It's the only way to
convince him!" cried Barbican, hastily turning to the Frenchman.

"Hand me over that ruler, Ardan!" yelled the Captain. "The heavy one!
It's the only way now left to bring him to reason!"

"Look here, Barbican and M'Nicholl!" cried Ardan, at last making himself
heard, and keeping a tight hold both on the cord and the ruler. "This
thing has gone far enough! Come. Stop your talk, and answer me a few
questions. What do you want of this cord, Barbican?"

"To describe a parabolic curve!"

"And what are you going to do with the ruler, M'Nicholl!"

"To help draw a true hyperbola!"

"Promise me, Barbican, that you're not going to lasso the Captain!"

"Lasso the Captain! Ha! ha! ha!"

"You promise, M'Nicholl, that you're not going to brain the President!"

"I brain the