Again he struggled, the sweat standing out on his forehead inside of his diving helmet.
At last he managed to turn one wrist and got the point of the knife again into the fish's body.
He cut and twisted as best he could and felt the ray of fire quiver with pain and rage.
The fish could not stand the cutting and presently raised its head in order to make a new move.
Exerting all of his strength, Dave made a slash at the head and cut into the light on the fish's snout.
A rush of phosphorescent blood followed, and on the instant all of the light died out in the creature's body.
Again Dave made a cut, striking deep into the fish, so deeply in fact that he made an ugly scratch on his father's neck.
This last blow was too much for the ray of fire, and slowly it fell away and floated off, Dave did not know to where.
Freed from his captor, Amos Fearless sank in a heap at the door of the diving bell.
Was he dead?