Animal Life in the Sea—Medusae—Food of the Whale—Phosphoric Light—Cause thereof—Luminosity of the Ocean.
 
Reference has elsewhere been made in this volume to the immense amount of animal life that exists in the ocean, not only in the form of fish of all sizes, but in that of animalcules, which, although scarcely visible to the naked eye, are, in some cases, so innumerable as to give a distinct colouring to the water.
 
The Medusae, or, more familiarly, sea blubbers, are seen in the waters that lave our own shores. They are of various sizes, from that of a large plate to a pin-head. They are almost colourless, like clear jelly, and when carelessly observed, seem to be dead objects drifting with the tide; but a closer observation shows that they are possessed of life, though not of a particularly active kind, and that they swim by alternate contractions and expansions of their bodies. These creatures constitute a large part of the whale’s food. Some of them are flat, some semi-globular, others are bell-shaped, while some have got little heads and small fins. Of these last it is said that each little creature has no fewer than three hundred and sixty thousand minute suckers on its head with which it seizes its prey. When we think of the exceeding smallness of the creatures thus preyed upon, and consider the fact that each little thing must obtain food by making war upon some creatures still smaller than itself, we are led almost in spite of ourselves into that mysteriously metaphysical question—infinitesimal divisibility; which may be translated thus—the endless division and subdivision of atoms. This subject has puzzled the heads of the profoundest philosophers of all ages; we will not, therefore, puzzle our readers with it any further.
 
Scoresby tells us that the colour of the Greenland Sea varies from ultramarine blue to olive-green, from the purest transparency to striking opacity; and that these colours are permanent, and do not depend on the state of the weather, but on the quality of the water. He observed that whales were found in much greater numbers in the green than in the blue water; and he found, on examining the former with the microscope, that its opacity and its colour were due to countless multitudes of those animalcules on which the whale feeds.
 
We need scarcely remark that it is utterly beyond the power of man to form anything approaching to a correct conception of the amount of life that is thus shown to exist in the ocean. Although it has pleased the Creator to limit our powers, yet it has also pleased him to leave the limit of those powers undefined. We may not, indeed, ever hope in this life to attain to perfect knowledge, nevertheless, by “searching” we may “find out wisdom;” and certain it is, that, although there undoubtedly must be a point of knowledge on any given subject which man cannot reach, there is in man a power incessantly to extend his knowledge and increase his powers of conception, by each successive effort that he makes in his course from the cradle to the grave.
 
Even although we were told the exact number of the little creatures that inhabit the sea, we could not, by any simple effort of the mind, however powerful, form a conception of what that number implied. We might shut ourselves up like the hermits of old, abstract our thoughts from all other things, and ponder the subject for weeks or months together, and at the termination of our effort we should be as wise as we were at its commencement, but no wiser. But by searching round the subject, and comparing lesser things with greater, although we should still fail to arrive at a full comprehension of the truth, we may advance our powers of conception very considerably beyond the point attained by our first effort; and which point, as we have said, could not be surmounted by a hair’s breadth by the mere exertion of simple or abstract thought.
 
Dr Scoresby’s remarks on the subject of animal life in the ocean, are so graphic and curious that we extract the passages verbatim from the admirable memoir of that gentleman, written by his nephew. He says:
 
“I procured a quantity of snow from a piece of ice that had been washed by the sea, and was greatly discoloured by the decomposition of some peculiar substance upon it. A little of this snow dissolved in a wine-glass appeared perfectly nebulous—the water being found to contain a great number of semi-transparent spherical substances, with others resembling small portions of fine hair. On examining these substances with a compound microscope, I was enabled to make the following observations:—
 
“The semi-transparent globules appeared to consist of an animal of the medusa kind. It was from one-twentieth to one-thirtieth of an inch in diameter. Its surface was marked with twelve distinct patches, or nebulae, of dots of a brownish colour. These dots were disposed in pairs, four pairs or sixteen pairs alternately, composing one of the nebula. The body of the medusa was transparent. When the water containing these animals was heated, it emitted a very strong odour, in some respects resembling the smell of oysters when thrown on hot coals, but much more offensive.
 
“The fibrous or hair-like substances were more easily examined, being of a darker colour. They varied in length from a point to one-tenth of an inch; and when highly magnified, were found beautifully moniliform. Whether they were living animals, and possessed of locomotion, I could not ascertain. They possessed the property of decomposing light, and in some cases showed all the colours of the spectrum very distinctly.
 
“I afterwards examined the different qualities of sea water, and found these substances very abundant in that of an olive-green colour; and also occurring, but in lesser quantity, in the bluish-green water. The number of medusae in the olive-green water was found to be immense. They were about one-fourth of an inch asunder. In this proportion, a cubic inch of water must contain 64; a cubic foot 110,592; a cubic fathom 23,887,872; and a cubic mile about 23,888,000,000,000,000.”
 
Of course we have, in the last two numbers, reached the utterly incomprehensible; but Dr Scoresby goes into comparisons which help us a little, at least to ascertain how hopelessly beyond our conceptions such numbers are.
 
“From soundings made in the situation where these animals were found, it is probable the sea is upwards of a mile in depth; but whether these substances occupy the whole depth is uncertain. Provided, however, the depth to which they extend be but two hundred and fifty fathoms, the above immense number of one species may occur in the space of two miles square. It may give a better conception of the amount of medusae in this extent, if we calculate the length of time that would be requisite, with a certain number of persons, for counting this number. Allowing that one person could count a million in seven days, which is barely possible, it would have required that eighty thousand persons should have started at the creation of the world to complete the enumeration at the present time!
 
“What a stupendous idea this gives of the immensity of creation, and of the bounty of Divine Providence in furnishing such a profusion of life in a region so remote from the habitations of men!
 
“The larger portion of these medusae, consisting of transparent substances of a lemon-yellow colour, and globular form, appeared to possess very little power of motion. Some of them were seen advancing by a slight waving motion, at the rate of a hundred and eightieth of an inch in a second; and others, spinning round with considerable celerity, gave great interest and liveliness to the examination. But the progressive motion of the most active, however distinct and rapid it might appear under a high magnifying power, was, in reality, extremely slow; for it did not exceed an inch in three minutes. At this rate they would require one hundred and fifty-one days to travel a nautical mile.
 
“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 c............