I see it perfectly....

Ah, the bandit, the heretic!" And he extended his threatening fist toward a point in the horizon exactly opposite to the one upon which the periscope was appearing.
Through the blue circle of the glasses Ferragut saw this tube climbing up and up, growing larger and larger.

It was no longer a stick, it was a tower; and from beneath this tower was coming up on the sea a base of steel spouting cascades of smoke,--a gray whale-back that appeared little by little to be taking the form of a sailing vessel, long and sharp-pointed.
A flag was suddenly run up upon the submarine.

Ulysses recognized it.
"They are going to shell us!" he yelled to Toni.

"It's useless to keep up the zigzagging.