"The vastness of their numbers, and their exceeding minuteness, are circumstances, discovered in the examination of these animalcules, of uncommon interest. In a drop of water examined by a power of 28.224 (magnified superficies) there were fifty in number, on an average, in each square of the micrometer glass, of an eight hundred and fortieth of an inch; and as the drop occupied a circle on a plate of glass containing 529 of these squares, there must have been, in this single drop of water, taken out of the yellowish-green sea, in a place by no means the most discoloured, about 26,450 animalcules. Hence, reckoning sixty drops to a dram, there would be a number in a gallon of water exceeding, by one half the amount of the population of the whole globe! It gives a powerful conception of the minuteness and wonders of creation, when we think of more than twenty-six thousand animals living, obtaining subsistence, and moving perfectly at their ease, without annoyance to one another, in a single drop of water... A whale requires a sea, an ocean, to sport in. About one hundred and fifty millions of these animalcules would have abundant room in a tumbler of water!" But besides furnishing food to the whale, and, no doubt, to many other of the inhabitants of the deep, those medusae are the cause of the phosphorescent light that sometimes glows on the ocean with resplendent brilliancy. We see this light oftentimes on our own coasts. It is usually of a pale bluish-white colour, more or less intense, apparently, according to the condition of the creatures by which it is emitted. It can only be seen at night. We have seen it on the west coast of Scotland, so bright that the steamer in which we sailed left behind her what appeared to be a broad highway of liquid fire. At times it requires vigorous motion, such as takes place when an oar is dipped, a stone thrown, or paddle-wheels dashed into the water; but at other times, the mere motion of the ocean swell, even in calm weather, is sufficient to stir up the lambent light and cause the crest of every undulation to glitter as if tipped with burnished silver. In such circumstances we have seen the ends of the oars of a boat silvered with it when lifted out of the wave, and the drops which fell from them before being redipped resembled the most beautiful diamonds. Mr P.H. Gosse, in his interesting work, "The Ocean," gives the following account of this luminosity of the sea, as witnessed by himself on one occasion: