In the second place, I became convinced that the myriads of microscopic organisms which pervaded the water did not light up their tiny lamps in response to a mechanical shock, such as would be produced by agitation of the medium in which they floated. There was no breeze, at any time, nor was there the faintest indication of a ripple on the glassy surface of the sea. Between the flashes of phosphorescence, the polished mirror of dark water was not blurred by so much as a breath. The sudden lighting up of myriads of infusorial lamps over vast areas of unruffled water was not due, therefore, to mechanical agitation, and must have had some other and more subtle cause. What the nature was of the impulse that stimulated whole square miles of floating protoplasm into luminous activity so suddenly as to produce the visual impression of an electric flash, I could not conjecture. The officers of the U. S. revenue cutter _McCulloch_ observed and recorded in Bering Sea, in August, 1898, a display of phosphorescence which was almost as remarkable as the one I am trying to describe [Footnote: _N.Y. Sun_, Nov. 11 1899.]; but in that case the sea was rough; there were no sudden flashes of appearance and disappearance; and the excitation of the light-bearing organisms may have been due--and probably was due--to mechanical shock.
In the third place, I observed that in the intervals between the flashes, when the water was dark, all objects immersed in that water were luminous. The ship's copper was so bright that I could count every tack and seam; the rudder was lighted to its lowest pintle; and medusae, or jelly-fish, drifting past, with slow pulsations, at a depth of ten or twelve feet, looked like submerged moons. It thus appeared that protozoa floating freely in the water lighted their lamps only in response to excitation, of some sort, which affected, almost instantaneously, areas many square miles in extent; while those that were attached to, or in contact with, solid matter kept their lamps lighted all the time.
During one of the periods of illumination, which lasted several minutes, I hauled up a bucketful of the phosphorescent liquid and took it into the cabin. Nothing whatever could be seen in it by artificial light, but when the light had been removed, the inside of the bucket glowed, although the water itself remained dark.