Nature's Teachings: Human Invention Anticipated by Nature. J. G. Wood

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СКАЧАТЬ Through which mine eye still giddily pursued it.”

      So deeply ingrained is the poetical notion of the sailing powers attributed to the nautilus, that many people are quite incredulous when they are told that there is just as much likelihood of seeing a mermaid curl her hair as of witnessing a nautilus under sail. How the creature in question does propel itself will be described in the course of the present chapter; and the reader will see that although one parallel between Nature and Art in the nautilus does not exist, there are several others which until later days have not even been suspected.

      It is, therefore, partially true that science does destroy romance. But, though she destroys, she creates, and she gives infinitely more than she takes away, as is shown in the many late discoveries which have transformed the whole system of civilised life. Sometimes, as in the present instance, she discovers one analogy while destroying another, and though she shatters the legend of the sailing nautilus, she produces a marine animal which really does sail, and does not appear to be able to do anything else. This is the Velella, a figure of which, taken from a specimen in my collection, is given in the illustration, and drawn of the natural size.

      It is one of that vast army of marine creatures known familiarly by the name of “jelly-fishes,” just as lobsters, crabs, shrimps, oysters, whelks, periwinkles, and the like, are lumped together under the title of “shell-fish.” As a rule, these creatures are soft, gelatinous, and, in fact, are very little more than sea-water entangled in the finest imaginable mesh-work of animal matter; so fine, indeed, that scarcely any definite organs can be discovered. The Velella, however, is remarkable for having a sort of skeleton, if it may be so called, consisting of two very thin and horny plates, disposed, as shown in the illustration, so as to form an exact imitation (or perhaps I should say a precursor) of a raft propelled by a sail. Indeed, the Latin name Velella signifies a little sail.

      

VELELLA (NATURAL SIZE). SAILING RAFT.

      How well deserved is the name may be seen by the following graphic account of a Velella fleet sent to me by a lady who takes great interest in practical zoology:—

      “The specimens which I send came from Tenby, a very rough sea having driven a large living fleet of them on that coast.

      “When in life, they are semi-transparent, and radiant in many rainbow-tinted colours. They came floating towards me in all their fragile beauty on the rough sea waves. I succeeded in capturing some of them, and preserved the only portion available for my collection.

      “They are extremely tender, and by no means with which I am acquainted can be preserved more than these skeleton-like cartilaginous plates. They soon dissolve in either spirits of wine or water, and lose every vestige of their shape and substance. The upright, thin, pellucid plate has the appearance of a fairy-like miniature sail, and apparently acted as such when the creature was floating with its long and many-tinted tentacles pendent from its lower surface.

      “Although widely distributed, they are seldom seen on our own coast, although sometimes driven there from the warmer regions by stress of wind and waves.

“These little creatures had never before been seen at Tenby, but when I asked a native bathing-woman whether she knew their name, she immediately replied, ‘Sea-butterflies.’ Although the name was evidently of her own invention, it was most appropriate and poetical. I have always found the Welsh people abound more than any other nation in pretty and characteristic synonyms.”[A]

[A] By sailors the Velella is popularly known by the name of “Sally-man;” i.e. Sallee-man.

      In answer to a letter in which I asked the writer for some further information concerning the Velella, sending also an outline sketch of the animal, which I asked the writer to fill in with the proper colours, I received the following reply:—

      “I will do my best to answer your questions, and to give you what information I can concerning the creatures.

      “When seen at Tenby, they were all floating on the surface of the sea, the tentacles only being submerged. My specimens floated for a very short time after capture, death following so quickly that I was obliged to set to work at once with camel’s-hair brush and penknife to take away the gelatinous part. Indeed, decomposition took place so rapidly, that Velellas and myself were simultaneously threatened with extermination.

      “Both raft and sail were equally enveloped in a soft, gelatinous covering, certainly not more than the sixteenth of an inch in thickness, except under the centre of the raft, where it became slightly thicker. The covering of the sail was exceedingly thin, and like a transparent and almost invisible soft skin. The sail is very firmly attached to the raft, as they did not separate when decomposition began.

      “The tentacles were entirely composed of the same soft, jelly-like substance as that of the envelope, and every part was iridescent in a sort of vapoury transparent cloud of many-tinted colours, blue and pale crimson predominating. I have filled up to the best of my memory the little sketch, and only wish you could have seen the Velellas as I did, in their full life and beauty.”

      Two of the specimens here mentioned are in my collection, and beautiful little things they are. The two plates are not thicker than ordinary silver paper, but are wonderfully strong, tough, and elastic. The oval horizontal plate, or raft, if it may be so called, is strengthened by being corrugated in concentric lines, and having a multitude of very fine ribs radiating from the centre to the circumference. It is slightly thickened on the edges, evidently for the attachment of the tentacles.

      The perpendicular plate, or sail, does not occupy the larger diameter of the raft, but stretches across it diagonally from edge to edge, rising highest in the centre and diminishing towards the edges, so that it presents an outline singularly like that of a lateen sail. It is rather curious that the magnifying glass gives but little, if any, assistance to the observer, the naked eye answering every purpose. Even the microscope is useless, detecting no peculiarity of structure. I tried it with the polariscope, scarcely expecting, but rather hoping, to find that it was sensitive to polarised light. But no such result took place, the Velella being quite unaffected by it.

      The corresponding illustration is a sketch of a raft to which a sail is attached. Such rafts as this are in use in many parts of the world, the sail saving manual labour, and the large steering oar answering the double purpose of keel and rudder. In the Velella, the tentacles, though they may not act in the latter capacity, certainly do act in that of the former, and serve to prevent the little creature from being capsized in a gale of wind.

The Boat.

       Table of Contents

      There is no doubt that the first idea of locomotion in the water, independently of swimming, was the raft; nor is it difficult to trace the gradual development of the raft into a Boat. The development of the Kruman’s canoe into the Great Eastern, or a modern ironclad vessel, is simply a matter of time.

      It is tolerably evident that the first raft was nothing more than a tree-trunk. Finding that the single trunk was apt to turn over with the weight of the occupant, the next move was evidently to lash two trunks side by side.

      Next would come the great advance of putting the trunks at some distance apart, and connecting them with cross-bars. This plan would obviate СКАЧАТЬ