At that moment there was a flash, and a brilliant blue-light burst out on the surface of the black water, sending a glare all round from where it floated on the trigger life-buoy, which had been detached and glided away astern, while directly after a second blue-light blazed out from the stern of the boat, showing the men dipping their oars lightly, and two forward and two astern shading their eyes and scanning the flashing and sparkling water.
