"Fire!"

There was a sharp click from the electric firing switch and a tiny spurt of bluish flame.

A shock like that of an earthquake followed. The mighty explosion seemed to rend the turret.

It had not died out before the glasses of the gunnery officer, the inventor and the gun-pointer were bearing on the distant target and the boats scurrying toward it. From the bridge and the quarter deck similar scrutiny was brought to bear.

Chaosite was almost smokeless, so their vision was not obscured, as with the old-fashioned powder—even the so-called "smokeless" making quite a smother.

"Hit, sir!" shot out Cooper dryly, as the signal man in the target boat wig-wagged the news.

"Now let the Idaho folks get busy!" cried the delighted gun crew.

The new explosive and the new gun had proven themselves one of the biggest naval successes of many a day.