NATURE'S TEACHINGS 
 
 HUMAN INVENTION 
 ANTICIPATED BY NATURE 
 
 BY THE LATE 
 
 REV. J. G. WOOD, M.A., F.L.S., ETC. 
 
 AUTHOR OF " HOMES WITHOUT HANDS," 
 
 "MAN AND BEAST, HERE AND HEREAFTER," ETC. 
 
 NEW AND.REVISED EDITION 
 
 LONDON 
 J. S. VIRTUE & CO., LIMITED, 26, IVY LANE 
 
 PATERNOSTER ROW
 
 LONDON : 
 
 MLISTE1) BY J. g. Vli'.TUK AMD 00., LDHTKD. 
 CITY BOAD.
 
 PKEFACE, 
 
 A GLANCE at almost any page of this work will denote 
 its object. It is to show the close connection between 
 Nature and human inventions, and that there is scarcely an 
 invention of man that has not its prototype in Nature. And 
 it is worthy of notice that the greatest results have been 
 obtained from means apparently the most insignificant. 
 
 There are two inventions, for example, which have changed 
 the face of the earth, and which yet sprang from sources that 
 were despised by men, and thought only fit for the passing 
 sport of childhood. I allude, of course, to Steam and Elec- 
 tricity, both of which had been child's toys for centuries before 
 the one gave us the fixed engine, the locomotive, and the 
 steamboat, and the other supplied us with the compass and 
 the electric telegraph. 
 
 In the course of this work I have placed side by side a 
 great number of parallels of Nature and Art, making the 
 descriptions as terse and simple as possible, and illustrating 
 them with more than seven hundred and fifty figures. The 
 corollary which I hope will be drawn from the work is evident 
 enough. It is, that as existing human inventions have been 
 anticipated by Nature, so it will surely be found that in 
 Nature lie the prototypes of inventions not yet revealed to 
 man. The great discorerers of the future will, therefore, be those 
 
 2090879
 
 Vlll PREFACE. 
 
 who will look to Nature for Art, Science, or Mechanics, 
 instead of taking pride in some new invention, and then finding 
 that it has existed in Nature for countless centuries. 
 
 I ought to mention that the illustrations are not intended to 
 be finished drawings, but merely charts or maps, calling 
 attention to the salient points.
 
 CONTENTS. 
 
 NAUTICAL. 
 
 CHA*. P10 
 
 I. THE RAFT . 1 
 
 II. THE OAR, THE PADDLE, AND THE SCREW ..... 12 
 
 III. SUBSIDIARY APPLIANCES. PART I. 23 
 
 IV. SUBSIDIARY APPLIANCES. PART II 34 
 
 V. SUBSIDIARY APPLIANCES. PART III. THE BOAT-HOOK AND 
 
 PUNT-POLE. THE LIFE-BUOY AND PONTOON-RAFT . 44 
 
 WAE AND HUNTING. 
 
 I. THE PITFALL, THE CLUB, THE SWORD, THE SPEAR AND DAGGER . 50 
 II. POISON, ANIMAL AND VEGETABLE. PRINCIPLE OF THE BARB . 62 
 
 III. PROJECTILE WEAPONS AND THE SHEATH 74 
 
 IV. THE NET .85 
 
 V. REVERTED SPIKES 102 
 
 VI. THE HOOK. DEFENSIVE ARMOUR. THE FORT . . . .115 
 VII. SCALING INSTRUMENTS. DEFENCE OF FORT. IMITATION. THE 
 
 FALL-TRAP 132 
 
 VIII. CONCEALMENT. DISGUISE. THE TRENCH. POWER OF GRAVITY. 
 
 MISCELLANEA ... . 144 
 
 AECHITEOTUEE. 
 
 I. THE HUT, TROPIC AND POLAR. PILLARS AND FLOORING. 
 TUNNEL ENTRANCE OF THE IGLOO. DOORS AND HINGES. 
 
 SELF-CLOSING TRAP-DOORS 159 
 
 II. WALLS, DOUBLE AND SINGLE. PORCHES, EAVES, AND WINDOWS. 
 
 THATCH, SLATES, AND TILES 177 
 
 in. THE WINDOW. GIRDERS, TIES, AND BUTTRESSES. THE TUNNEL. 
 
 THE SUSPENSION-BRIDGE 190 
 
 IV. LIGHTHOUSES. THE DOVETAIL. THE DAM. SUBTERRANEAN 
 
 DWELLINGS. THE PYRAMIDS. MORTAR, PAINT, AND VARNISH . 207 
 
 b
 
 X CONTENTS. 
 
 TOOLS 
 
 CHAP. f. ~ PAGB 
 
 I. THE DIGGING-STICK. SPADE. SHEARS AND bcissoRS. CHISEL 
 
 AND ADZE. THE PLANE AND SPOKESHAVE 222 
 
 II. THE SAW AND ITS VARIETIES 239 
 
 in. BORING TOOLS. STRIKING TOOLS. GRASPING TOOLS . . .249 
 IV. POLISHING TOOLS. MEASURING TOOLS 263 
 
 OPTICS. 
 
 I. THE MISSIONS OF HISTORY. THE CAMERA OBSCURA. LONG 
 AND SHORT SIGHT. STEREOSCOPE AND PSBUDOSCOPE. 
 MULTIPLYING-GLASSES 276 
 
 II. THE WATER-TELESCOPE. IRIS OF THE EYE. MAGIC LANTERN. 
 
 THE SPECTROSCOPE. THE THAUMATROPE 291 
 
 USEFUL AETS. 
 
 I. PRIMITIVE MAN AND His NEEDS. EARTHENWARE. BALL-AND- 
 SOCKET JOINT. TOGGLE OR KNEE JOINT 308 
 
 II. CRUSHING INSTRUMENTS. THE NUT-CRACKERS, ROLLING-MILL, 
 AND GRINDSTONE. PRESSURE OF ATMOSPHERE. SEED DIBBLES 
 AND DRILLS 320 
 
 III. CLOTH-DRESSING. BRUSHES AND COMBS. BUTTONS, HOOKS AND 
 
 EYES, AND CLASP 339 
 
 IV. THE STOPPER, OR CORK. THE FILTER 350 
 
 V. THE PRINCIPLE OF THE SPRING. THE ELASTIC SPRING. 
 
 ACCUMULATORS. THE SPIRAL SPRING 360 
 
 VI. SPIRAL AND RINGED TISSUES. VARIOUS SPRINGS m NATURE 
 
 AND ART i ..... 375 
 
 VII. FOOD AND COMFORT 390 
 
 VIII. DOMESTIC COMFORT . . . . ' 400 
 
 IX. ARTIFICIAL WARMTH. RING AND STAPLE. THE FAN . . . 412 
 
 X. WATER, AND MEANS OF PROCURING IT . . . . . . 422 
 
 XI. AEROSTATICS. WEIGHT OF AIR. EXPANSION BY HEAT . . 436 
 
 XII. DITTO CONTINUED 447 
 
 XIII. TELESCOPIC TUBES. DIRECT ACTION. DISTRIBUTION OF WEIGHT. 
 
 TREE-CLIMBING. THE WHEEL 460 
 
 XIV. PAPER AND MOULDING 472 
 
 XV. ELECTRICITY AND GALVANISM .'.'.*. . . . 482 
 
 XVI. TILLAGE. DRAINAGE. SPIRAL PRINCIPLE. CENTRIFUGAL FORCE 492 
 XVII. OSCILLATION. UNITED STRENGTH. THE DOME .... 504 
 
 ACOUSTICS. 
 
 I. PERCUSSION. THE STRING AND REED. THE TRUMPET. EAR- 
 TRUMPET. STETHOSCOPE ... . 513
 
 NAUTICAL. 
 
 CHAPTER I. 
 
 Poetry and Science. The Papei Nautilu? and the Sail. Montgomery's " Pelican 
 Island." The Nautilus replaced by theVelella. The SailingRaft of Nature 
 and Art. Description of a Velella Fleet off Tenhy. The Natural Kaft and 
 its Sail. The Boats of Nature and Art. Man's first Idea of a Boat. The 
 Kruman's Canoe and the Great Eastern. Gradual Development of the Boat. 
 The Outrigger Canoe a Mixture of Baft and Boat. Natural Boats. The 
 Water-enails. The Sea-anemones. The Egg-boat of the Gnat. The 
 Skin-boat of the same Insect. Shape and Properties of the Life-boat anti- 
 cipated in Nature. Natural Boat of the Stratiomys. 
 
 THE RAFT. 
 
 IT lias been frequently said that the modern developments 
 of science are gradually destroying many of the poetical 
 elements of our daily lives, and in consequence are reducing 
 us to a dead level of prosaic commonplace, in which existence 
 is scarcely worth having. The first part of this rather 
 sweeping assertion is perfectly true, but, as we shall presently 
 see, the second portion is absolutely untrue. 
 
 Science has certainly destroyed, and is destroying, many of 
 the poetic fancies which made a part of daily life. It must 
 have been a considerable shock to the mind of an ancient 
 philosopher when he found himself deprived of the semi- 
 spiritual, semi-human beings with which the earth and water 
 were thought to be peopled. And even in our own time and 
 country there is in many places a still lingering belief in the 
 existence of good and bad fairies inhabiting lake, wood, and 
 glen, the successors of the Naiads and Dryads, the Fauns and 
 Satyrs, of the former time. Many persons will doubtless be 
 surprised, even in these days, to hear that the dreaded Mael- 
 strom is quite as fabulous as the Symplegades or Scylla and 
 
 F
 
 2 NATURE'S TEACHINGS. 
 
 Oharybdis, and that the well-known tale of Edgar Poe is 
 absolutely without foundation. 
 
 Perhaps one of the prettiest legends in natural history is 
 that of the Paper Nautilus, with which so much poetry is 
 associated. We have all been accustomed from childhood to 
 Pope's well-known lines beginning 
 
 " Learn of the little Nautilus to sail," 
 
 and some of us may be acquainted with those graceful verses 
 of James Montgomery, in his " Pelican Island : " 
 
 " Light as a flake of foam upon the wind, 
 Keel upward, from the deep emerged a shell, 
 Shaped like the moon ere half her horn is filled. 
 Fraught with young life it righted as it rose, 
 And moved at will along the yielding water. 
 The native pilot of this little bark 
 Put out a tier of oars on either side, 
 Spread to the wafting hreeze a two-fold sail, 
 And mounted up and glided down the billow 
 In happy freedom, pleased to feel the air, 
 And wander in the luxury of light. 
 * * * 
 
 It closed, sank, dwindled to a point, then nothing, 
 While the last bubble crowned the dimpling eddy 
 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
 
 THE VELELLA AND SAILING RAFT. 3 
 
 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 
 
 VELELLA (NATURAL SIZE). 
 
 SAILING RAPT. 
 
 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. 
 
 How well deserved is the name may be seen by the follow- 
 ing 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
 
 4 NATURE S TEACHINGS. 
 
 substance. The upright, thin, pellucid plate has the appear- 
 ance 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."* 
 
 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 
 
 * By sailors tbe Velella is popularly known by the name of " Sally-man ; " 
 .. Sallee-man.
 
 THE BOAT. 
 
 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 con- 
 centric 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. 
 
 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
 
 6 NATURE'S TEACHINGS. 
 
 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 even the chance of the upsetting of 
 the raft, and it still survives in that curious mixture of the 
 raft and canoe, the outrigger boat of the Polynesians, which 
 no gale of wind can upset. It may be torn to pieces by the 
 storm, but nothing can capsize it as long as it holds together. 
 
 Laying a number of smaller logs or branches upon the bars 
 which connect the larger logs is an evident mode of forming a 
 continuous platform, and thus the raft is completed. It would 
 not be long before the superior buoyancy of a hollow over a 
 solid log would be discovered, and so, when the savage could 
 not find a log ready hollowed to his hand, he would hollow 
 one for himself, mostly using fire in lieu of tools. The pro- 
 gress from a hollowed log, or "dug-out," as it is popularly 
 called, to the bark canoe, and then the built boat, naturally 
 followed, the boats increasing in size until they were developed 
 into ships. 
 
 Such, then, is a slight sketch of the gradual construction of 
 the Boat, based, though perhaps ignorantly, on the theory of 
 displacement. Now, let us ask ourselves whether, in creation, 
 there are any natural boats which existed before man came 
 upon the earth, and from which he might have taken the idea 
 if he had been able to reason on the subject. The Paper 
 Nautilus is, of course, the first example that comes before the 
 mind ; but although, as we have seen, the delicate shell of the 
 nautilus is not used as a boat, and its sailing and rowing powers 
 are alike fabulous, there is, as is the case with most fables, a 
 substratum of truth, and there are aquatic molluscs which form 
 themselves into boats, although they do not propel themselves 
 with sails or oars. 
 
 Many species of molluscs possess this art, but we will select 
 one as an example of them all, because it is very plentiful in 
 our own country, and may be found in almost any number. It 
 is the common WATER-SNAIL (Limnceastagnalis), which abounds 
 in our streams where the current is not very strong. Even in 
 tolerably swift streams the Limnaea may be found plentifully in 
 any bay or sudden curve where a reverse current is generated,
 
 NATURAL AND ARTIFICIAL BOATS. 
 
 and therefore the force of the stream is partially neutralised. 
 These molluscs absolutely swarm in the Cherwell, and in the 
 multitudinous ditches which drain the flat country about 
 Oxford into that river as well as the Isis. 
 
 Belonging to the Gasteropods, the Water-snail can crawl 
 over the stones or aquatic vegetation, just as the common 
 garden snail or slug does on land. But it has another mode 
 of progression, which it very often employs in warm weather. 
 It ascends to the surface of the water, reverses its position so 
 
 "DUO-OUT" BOAT OP VARIOUS PABTS OP 
 TUB WOULD. 
 
 WATEtt- SNAIL ACTING AS BOAT. 
 
 BIBCH-BABK CANOE. 
 
 PUPA SKIN OP GNAT ACTING AS BOAT. 
 
 that the shell is downward, spreads out the foot as widely as 
 possible, and then contracts it in the centre, so as to form it 
 into a shallow boat. 
 
 The carrying capacity of this boat is necessarily small, but 
 as the shell and nearly the whole of the animal are submerged, 
 and therefore mostly sustained by the water, a very small 
 amount of flotative power is sufficient for the purpose. Some-
 
 NATURE S TEACHINGS. 
 
 times, on a fine day, whole fleets of these natural boats may 
 be seen floating down the stream, thus obtaining a change of 
 locality without any personal exertion. 
 
 In perfectly still water, where no current can waft the 
 Limnaea on its easy voyage, it still is able to convey itself from 
 one place to another. By means of extending and contracting 
 the foot, it actually contrives to crawl along the surface of the 
 water almost as readily as if it were upon the under side of 
 some solid body, and, although its progress is slow, it is very 
 steady. Another very common British water-snail, the Pouch - 
 shell (Physa fontinalis), has almost exactly the same habits. 
 Jleference will be made to the Pouch-shell on another page. 
 
 The capacity for converting the body into a boat is not con- 
 fined to the molluscs, but is shared by many other animals. Take, 
 for example, the well-known marine animals, called popularly 
 SEA- ANEMONES. As they appear when planted on the rocks, 
 they look as incapable of motion as the flowers whose names 
 they bear. Yet, by means of the flattened base, which they 
 use just as a snail uses its feet, they can manage to glide 
 along the rocks in any direction, though very slowly. 
 
 The base is capable of extension and contraction, and by 
 elongating one side of it, fixing the elongated portion, and 
 then raising the remainder of the base towards it, the animal 
 makes practically a series of very slow steps. This mode of 
 progression may often be seen in operation on the glass front 
 of an aquarium. 
 
 The same property of expansion and contraction enables 
 the Sea-anemones to convert their bodies into boats, and float 
 on the surface of the water. When one of these animals 
 wishes to swim, it ascends the object to which it is clinging 
 say the glass of the aquarium until it has reached the air. 
 It then very slowly, and bit by bit, detaches the upper part of 
 the base from the glass, allowing itself to hang with its 
 tentacles downward. These, by the way, are almost wholly 
 withdrawn when the animal is engaged in this business. By 
 degrees the whole of the base is detached from the glass except 
 a very tiny portion of the edge. The base is next contracted 
 in the middle into the form of a shallow cup, and, when this is 
 done, the last hold of the glass is released, and the animal 
 floats away, supported by its hollowed base.
 
 EGG-BOAT OF THE GNAT. 9 
 
 Entomologists are familiar with the following facts, and 
 were this work addressed to them alone, a simple mention of 
 the insect would be sufficient. But as this work is intended 
 for the general public, it will be necessary to give a descrip- 
 tion, though a brief one, of the wonderful manner in which an 
 insect, which we are apt to think is only too common, plays the 
 part of a boat at its entrance to life and just before its 
 departure from this world, not to mention its intermediate 
 state, to which reference will be made under another heading. 
 
 The insect in question is the common GNAT (Culex pipiem], 
 which makes such ravages upon those who are afflicted, like 
 myself, with delicate skins, and can have a limb rendered 
 useless for days by a single gnat-bite. 
 
 In this insect, the beginning and the end of life are so 
 closely interwoven, that it is not easy to determine which has 
 the prior claim to description, but we will begin with the egg. 
 
 With very few exceptions, such as the Earwig, which 
 watches over its eggs and young like a hen over her nest and 
 chickens, the insects merely deposit their eggs upon or close to 
 the food of the future young, and leave them to their fate. 
 The eggs of the Gnat, however, require different treatment. 
 The young larvae, when hatched, immediately pass into the 
 water in which they have to live, and yet the eggs are so consti- 
 tuted that they need the warmth of the sun in order to hatch 
 them. The machinery by which both these objects are attained 
 is singularly beautiful. 
 
 The shape of the egg very much resembles that of a common 
 ninepin, and the structure is such that it must be kept upright, 
 so that the top shall be exposed to the air and sun, and the 
 bottom be immersed in the water. It would be almost im- 
 possible that these conditions should be attained if the eggs 
 were either dropped separately into the water or fixed to 
 aquatic plants, as is the case with many creatures whose eggs 
 are hatched solely in or on the water. 
 
 As is the case with many insects, each egg when laid is 
 enveloped with a slight coating of a glutinous character, so 
 that they adhere together. And, in the case of the Gnat, this 
 material is insoluble in water, and hardens almost immediately 
 after the egg is deposited. Taking advantage of these pecu- 
 liarities, the female Gnat places herself on the edge of a floating
 
 10 NATURE'S TEACHINGS. 
 
 leaf or similar object, so that her long and slender hind-legs 
 rest on the water. In some mysterious way, the eggs, as they 
 are successively produced, are passed along the hind-legs, and 
 are arranged side by side in such a manner that they are 
 formed into the figure of a boat, being fixed to each other by 
 the glutinous substance which has already been mentioned. 
 
 It is a very remarkable fact, which assists in strengthening the 
 theory on which this book is written, that the lines of the best 
 modern life-boats are almost identical with those of the Gnat- 
 boat, and that both possess the power of righting themselves if 
 capsized. In all trials of a new life-boat, one of the most 
 important is that which tests her capability of self-righting ; and 
 any one who has witnessed such experiments, and has tried to 
 upset a Gnat-boat, cannot but be struck with the singular 
 similitude between the boat made by the hand of man and that 
 constructed by the legs of an insect, without even the aid of 
 eyes. 
 
 Push the Gnat-boat under water, and it shoots to the surface 
 like a cork, righting itself as it rises. Pour water on it, and 
 exactly the same result occurs, so that nothing can prevent it 
 from floating. Then, when the warm air has done its work in 
 hatching the enclosed young, a little trap- door opens at the 
 bottom of the egg, lets the young larvae into the water, and 
 away they swim. 
 
 Now we come to another phase of existence in which the 
 Gnat forms a boat. Every one knows the little active Gnat 
 larvae, with their large heads and slender bodies, much like 
 tadpoles in miniature. When they have reached their full 
 growth, and assume the pupal form, their shape is much 
 changed. The iore part of the body is still more enlarged, as 
 it has to contain the wings and legs, which have so great a 
 proportion to the body of the perfect Gnat. And, instead of 
 floating with its head downwards, and breathing through its 
 tail as it did when a larva, it now floats with the head upper- 
 most, and breathes through two little tubes. 
 
 Even in its iormer state the creature had something almost 
 grotesque in its aspect, the head, when magnified, looking 
 almost as like a human face as does that of a skate. But in 
 its pupal state it looks as if it had put on a large comical mask 
 much too large for it, very much like those paper masks which
 
 SKIN -BO AT OF THE GNAT. 11 
 
 are enclosed in crackers, and have to be worn by those who 
 draw them. 
 
 In process of time the pupa changes to a perfect Gnat within 
 this shelly case, able to move, but unable to eat. The body 
 shrinks in size, and the wings and legs are formed, both being 
 pressed closely to the body. "When the Gnat is fully developed, 
 the pupal skin splits along the back, and opens out into a 
 curiously boat-like shape, the front, which contains the heavier 
 part of the insect, being much the largest, and consequently 
 being able to bear the greatest weight. 
 
 By degrees, the Gnat draws itself out of the split pupal skin, 
 xesting its legs on it as fast as they are released. It then 
 shakes out its wings to dry, and finally takes to the air. 
 
 It is a really wonderful fact that the insect which, for three 
 stages in life namely, an egg, larva, and pupa lived in the 
 water, should in the fourth not only be incapable of aquatic 
 life, but should employ its old skin to protect it from that very 
 element in which it was living only a minute or two before. 
 
 Should the reader wish to examine for himself either the egg 
 or skin boat of the Gnat, he can easily procure them by search- 
 ing any quiet pond, or even an uncovered water-butt. They 
 are, of course, very small, averaging about the tenth of an 
 inch in length, and are nearly always to be found close to the 
 side either of pond or tub, being drawn there by the power of 
 attraction. 
 
 I may here mention that there are other dipterous insects 
 belonging to the genus Stratiomys, which undergo their meta- 
 morphosis in a very similar fashion. In these insects, the 
 larva breathes through the tail, and when it attains its pupal 
 condition, the actual insect is very much smaller than the 
 pupal skin, only occupying the anterior and enlarged part. 
 Indeed, the difference of size is so great, that several entomo- 
 logists believed the future Stratiomys to be but a parasite on the 
 original larva. The beautiful Chameleon-fly (Stratiomys cha- 
 mcekori) is a familiar example of these insects.
 
 NAUTICAL. 
 
 CHAPTER II. 
 
 THE OAR, THE PADDLE, AND THB SCBEW. 
 
 Propulsion by the Oar. Parallels in the Insect World. The " Water-boatman." 
 
 Its Boat-like Shape. The Oar-like Legs. Exact mechanical Analogy 
 between the Legs of the Insect and the Oars of the human Rower. 
 "Feathering" Oars in Nature and Art. The Water-boatman and the 
 Water-beetles. The Feet of the Swan, Goose, and other aquatic Birds. 
 The Cydippe, or Beroe. The Self-feathering Paddle-wheel. Indirect Force. 
 
 The Wedge, Screw, and Inclined Plane. " Sculling" a Boat. The 
 " Tanka " Girls of China. Mechanical Principle of the Screw, and ita 
 Adaptation to Vessels. Gradual Development of the Nautical Screw. 
 Mechanical Principle of the Tail of the Fish, the Otter, and the sinuous 
 Body of the Eel and Lampern. The Coracle and the Whirl wig-beetle. 
 
 Boat naturally reminds us of the Boatman. In the two 
 -*- gnat- boats which have been described there is no propel- 
 ling power used or needed, the little vessel floating about at 
 random, and its only object being to keep afloat. But there 
 are many cases where the propelling power is absolutely 
 essential, and where its absence would mean death, as much 
 as it would to a ship which was becalmed in mid ocean without 
 any means of progress or escape. There are, for example, 
 hundreds of creatures, belonging to every order of animals, 
 which are absolutely dependent for their very existence on 
 their power of propulsion, and I believe that there is not a 
 single mode of aquatic progression employed by man which has 
 not been previously carried out in the animal world. There 
 are so many examples of this fact that I am obliged to select a 
 very few typical instances in proof of the assertion. 
 
 Taking the Oar as the natural type of progression in the 
 water, we have in the insect world numerous examples of the 
 very same principle on which our modern boats are propelled.
 
 THE WATER- BOATMAN. 13 
 
 And it is worthy of notice, that the greater the improvement in 
 rowing, the nearer do we approach the original insect model. 
 
 The first which we shall notice is the insect which, from its 
 singular resemblance to a boat propelled by a pair of oars, has 
 received the popular name of WATER-BOATMAN. Its scientific 
 name is Notonecta glauca, the meaning of which we shall 
 presently see. It belongs to the order of Heteroptera, and is 
 one of a numerous group, all bearing some resemblance to each 
 other in form, and being almost identical in habits. Though 
 they can fly well, and walk tolerably, they pass the greater 
 part of their existence in the water, in which element they 
 find their food. 
 
 Predacious to a high degree, and armed with powerful weapons 
 of offence, it is one of the pirates of the fresh water, and may be 
 found in almost every pond and stream, plying its deadly vocation. 
 
 Its large and powerful wings seem only to be employed in 
 carrying it from one piece of water to another, while its first 
 and second pairs of legs are hardly ever used at all for progres- 
 sion. The last pair of legs are of very great length, and 
 furnished at their tips with a curiously constructed fringe of 
 stiff hairs. The body is shaped in a manner that greatly 
 resembles a boat turned upside down, the edge of the elytra 
 forming a sort of ridge very much like the keel of the boat. 
 
 "When the creature is engaged in swimming, it turns itself 
 on its back, so as to bring the keel downwards, and to be able 
 to cut the water with the sharp edge. From this habit it has 
 derived the name of Notonecta, which signifies an animal 
 which swims on its back. The first and second pairs of legs are 
 clasped to the body, and the last pair are stretched out as 
 shown in the illustration, not only looking like oars, but being 
 actually used as oars. 
 
 Now, I wish especially to call the reader's attention to the 
 curiously exact parallel between the water-boatman and the 
 human oarsman. As the reader may probably know, the oar 
 is a lever of the second order, i.e. the power comes first, then 
 the weight, and then the fulcrum. The arm of the rower 
 furnishes the power, the boat is the weight to be moved, and 
 the water is the fulcrum against which the lever acts. 
 
 I have more than once heard objections to this definition, 
 the objectors saying that the water was a yielding substance,
 
 14, NATURE'S TEACHINGS. 
 
 and therefore could not be the fulcrum. This objection, how- 
 ever, was easily refuted by taking a boat up a narrow creek, 
 and rowing with the oar-blades resting on the shore, and not in 
 the water. 
 
 Now, the swimming legs of the water-boatman are exact 
 analogues of the oars of a human rower. The internal muscles 
 at the juncture of the leg with the body supply the place of the 
 rower's arms, the leg itself takes the office of the oar, and the 
 
 OAK OF BOAT. 
 
 WATEB-BOATMAJf BOWING ITSELF. 
 
 OABSMAX ROWTSO. 
 
 body of the insect is the weight to be moved, and the water 
 supplies the fulcrum. Even the broad blade at the end of the 
 oar is anticipated by the fringe of bristles at the end of the leg, 
 and its sharpened edge by the shape of the insect's limb. 
 
 Besides these resemblances, there is another which is worthy 
 of notice. All rowers know that one of their first lessons is to 
 " feather " their oars, i.e. to turn the blade edgewise as soon 
 as it leaves the water. Nothing looks more awkward than 
 for a boatman to row without feathering. (We all must 
 remember the eulogy on the " Jolly Young Waterman," who 
 "feathered his oars with skill and dexterity.") In the first 
 place, he must lift his oar very high out of the water, and, in 
 the second, he will be impeded by any wind that happens to 
 come against the blades. 
 
 The Water-boatman, however, does not lift its legs out of the 
 water after every stroke, as a human boatman does, and there- 
 fore it has no need to feather in the same way. But there is 
 even greater need for a feathering of some kind in the insect's 
 leg, on account of the greater resistance offered by water than 
 by air, and this feathering is effected by the arrangement of the 
 blade-bristles, which spread themselves against the water as 
 the stroke is made, and collapse afterwards, so as to give as 
 little resistance as possible when the stroke is completed.
 
 " FEATHERING " OARS. 15 
 
 IN Art we have invented many similar contrivances, but I 
 believe that there is not one in which we have not been antici- 
 pated by Nature. Putting aside the insect which has just 
 been described, we have the whole tribe of water-beetles, in 
 which the same principle is carried out in an almost identical 
 manner. In the accompanying illustration, the oar, the rower, 
 and the boat are placed above one another, and next to them 
 are seen one of the oar-legs of the water-boatman and the 
 insect as it appears when swimming on its back. 
 
 Then, there is the foot of the duck, goose, swan, and various 
 other aquatic birds, in which the foot presents a broad blade 
 as it strikes against the water, and a narrow edge as it recovers 
 from the strode. Some years ago, a steam yacht was built 
 and propelled by feet made on the model of those of the swan. 
 She was a very pretty vessel, but art could not equal nature, 
 and at present the swan-foot propeller, however perfect in 
 theory, has not succeeded in action. Perhaps, if some nautical 
 engineer were to take it in hand, he would procure the desired 
 result. 
 
 Almost exactly similar is the mode of propulsion employed 
 by the lobster, the prawns and shrimps, their tails expanding 
 widely into a fan-like shape as they strike against the water, 
 and then collapsing when the stroke is withdrawn, so as to 
 allow them to pass through the water with the least possible 
 resistance. 
 
 The same principle is to be seen in the lively little Acaleph, 
 for which there is uniortunately no popular name, and which 
 we must therefore call by its scientific title of CYDIPPE, or 
 Beroe, these names being almost indifferently used. When full 
 grown, it is about as large as an acorn, and very much of the 
 same shape. It is as transparent as if made of glass, and, when 
 in the water, is only visible to practised eyes. 
 
 En passant, I may remark that the familiar term of " water," 
 when applied to diamonds, is owing to their appearance when 
 placed in distilled water. Those which can be at once 
 seen are called stones of the second water. Those which 
 cannot be seen, because their refractive powers are equal to 
 those of the water, are called " diamonds of the first water," 
 and are very much more valuable than the others. 
 
 As the Cydippe is, in fact, little more than sea-water,
 
 16 
 
 NATURE S TEACHINGS. 
 
 entangled in the slightest imaginable and most transparent 
 tissue of animal fibre, it is evident that the water and the 
 Cydippe must be of almost equal refracting power, and that 
 therefore the acaleph must be as invisible as diamonds of the 
 " first water." Indeed, I have often had specimens in a glass 
 jar which were absolutely invisible to persons to whom I wished 
 to show them. 
 
 But an experienced eye detects the creature at once. Along 
 its body, at equal distances, are eight narrow bands, over 
 which the colours of the rainbow are, though very faint, per- 
 petually rippling. This appearance is caused by the machinery 
 which impels the body, and which seems never to cease. Each 
 of these bands is composed of a vast number of tiny flaps, which 
 move up and down in regular succession, so as to cause the 
 light to play on their surfaces. And, as they move as if set on 
 hinges, they of course offer no resistance to the water after 
 their stroke is made. 
 
 Now let us compare these works of nature with those of art. 
 We have already seen the parallels of the oar, and we now come 
 
 CTDIPPE AND 
 PADDLES. 
 
 PRAWN SWIMMING. 
 FEET OF DUCK. 
 
 SKIP-FEATHERING PADDLE-WHEEL. 
 
 to those of the paddle-wheel. When paddle- steamers were 
 first invented, the blades were fixed and projected from the 
 wheel, as if they had been continuations of its spokes. It was 
 found, however, that a great waste of power, together with 
 much inconvenience, was caused by this arrangement. Not
 
 SELF-FEATHERING PADDLE-WHEEL 17 
 
 only was a considerable weight of water raised by each blade 
 after it passed the middle of its stroke, but the steam power 
 was given nearly as much to lifting and shaking the vessel as 
 to propulsion. 
 
 A new kind of paddle-wheel was then invented, in which 
 the blades were ingeniously jointed to the wheel, so that they 
 presented their flat surfaces to the water while propelling, and 
 their edges when the stroke was over. This, which is known by 
 the name of the "Self-feathering Paddle-wheel," was thought 
 to be a very clever invention, and so it was ; but not even the 
 inventors were likely to have known that if they had only 
 looked into the book of Nature, they might have found plenty 
 of self -feathering paddle-wheels, beside the few which my 
 limited space enables me to give. 
 
 If the reader will look at the illustration, he will see that on 
 one side is represented the self-feathering paddle-wheel of Art, 
 with its ingenious arrangement of rods and hinges. On the 
 other side there comes, first, the common Prawn, shown with its 
 tail expanded in the middle of its stroke. 
 
 Just below it is a Cydippe of its ordinary size, showing the 
 paddle-bands, one of which is drawn at the side much mag- 
 nified, so as to show the arrangement of the little paddles. 
 As to the tentacles which trail from the body, we shall treat of 
 them when we come to our next division of the subject of the 
 work. 
 
 Lastly, there is a representation of the self-feathering feet 
 of the Duck, the left foot expanded in striking the water, and 
 the right closed so as to offer no resistance when drawn forward 
 for another stroke. The swan's foot shows this action even 
 more beautifully than does that of the duck. 
 
 WE now come to another mode of propulsion, namely, that 
 which is not due to direct pressure of a more or less flat body 
 against the water, but to the indirect principle of the screw, 
 wedge, or inclined plane. 
 
 Space being valuable, I will only take two instances, namely, 
 the well-known mode of propelling a boat by a single oar 
 working in a groove or rowlock in the middle of the stern, and 
 the ordinary screw of modern steamers. 
 
 Most of my readers must have seen a sailor in the act of 
 
 c
 
 18 
 
 NATURE S TEACHINGS. 
 
 " sculling " a boat. A tolerably deep notch is sunk in the 
 centre of the stern, and the oar is laid in it, as shown in the 
 central illustration, on the right-hand side. The sailor then 
 takes the handle of the oar, and works it regularly backwards 
 and forwards, without taking the blade out of the water. The 
 boat at once begins to move forward, and, when the oar is 
 
 TAIL OF FISH. 
 
 SCREW OF STEAMER. 
 
 ' SCULLINO " A BOAT. 
 
 ACTION OF KUDDEB. 
 
 TAIL OF SEAL. 
 
 urged by a strong and experienced man, can be propelled with 
 wonderful speed. The well-known " Tanka " boat-girls of 
 China never think of using two oars, a single oar in the stern 
 being all-sufficient for the rapid and intricate evolutions 
 required in their business. 
 
 The mechanical process which is here employed is nothing 
 more than that of the inclined plane, or rather, the wedge, the 
 oar-blade forming the wedge, and the force being directed 
 against the stern of the boat, and so driving it through the 
 water. 
 
 The Rudder affords another example of a similar force, 
 although it is used more for directing than propelling a vessel. 
 Still, just as the scull is used not only for propelling, but for 
 steering the boat, the rudder, when moved steadily backwards 
 and forwards, can be used for propulsion as well as steerage. 
 In the absence of oars, this property is most useful, as I can 
 practically testify.
 
 PRINCIPLE OF THE SCREW. 19 
 
 So different in appearance are the screw and the inclined 
 plane, that very few people would realise the fact that the screw 
 is nothing but an inclined plane wound round a cylinder, or 
 rather, is a circular inclined plane. The ordinary corkscrew 
 is a good example of this principle, the cylinder being but aa 
 imaginary one. 
 
 Now, if the screw be turned round, it is evident that force is 
 applied just on the principle of the wedge, and this principle is 
 well shown in the various screw-presses, of which the common 
 linen-press is a familiar example, as was the original printing- 
 press, which still survives as a toy for children. 
 
 We all know the enormous force exerted by screws when 
 working in wood, and how, when the screw-driver is turned in 
 the reverse direction, the instrument is forced backwards, 
 though the operator is leaning against it with all his weight. 
 In fact, a comparatively small screw, if working in hard wood 
 or metal, so that the threads could not break, could lift a heavy 
 man. 
 
 Substitute water for wood or metal, and the result would be 
 the same in principle, though the resistance would be less. As 
 the loss of power by friction would prevent a large vessel from 
 being propelled by a stern oar moved like a scull, the idea was 
 invented of applying the same kind of power by a large screw, 
 which should project into the water from the stern of the 
 vessel. This modification, moreover, would have the advantage 
 of forcing the vessel forward when the screw was turned from 
 left to right, and drawing it back when turned in the opposite 
 direction, whereas the sculling oar would only drive it forward. 
 
 The principle was right enough, but there was at first a great 
 difficulty in carrying it out. Firstly, several turns of a large 
 screw were used, and were found to need power inadequate to 
 the effect. Then the screw was reduced to four separate blades, 
 and now only two are used, as shown in the illustration, 
 these saving friction, being equally powerful for propulsion, and 
 running less risk of fouling by rigging blown overboard or 
 other floating substances. 
 
 So much for Art. Now for the same principle as shown in 
 Nature, of which I can take but a very few instances. 
 
 The first and most obvious example is that of the Fish-tail, 
 which any one may observe by watching ordinary gold fish in 
 
 c2
 
 20 NATURE'S TEACHINGS. 
 
 a bowl. Their progression is entirely accomplished by the 
 movement of the tail from side to side, exactly like that of the 
 sculling oar, and moreover, like the oar, the tail acts as rudder 
 as well as propeller. 
 
 The force with which this instrument can be used may be 
 estimated by any one who is an angler, and knows the lightning- 
 like rush of a hooked trout, or who has seen the wonderful 
 spring with which a salmon shoots clear out of the water, and 
 leaps up a fall several feet in height. This is not done, as 
 many writers state, by bending the body into a bow-like form, 
 and then suddenly straightening it, but by the projectile 
 force which is gained by moving the tail backwards and 
 forwards as a sculler moves his oar. 
 
 Perhaps some of my readers have seen the wonderful speed, 
 ease, and grace with which an Otter propels itself through the 
 water. As the otter feeds on fish, and can capture even the 
 salmon itself, its powers of locomotion must be very great 
 indeed. And these are obtained entirely by means of the tail, 
 which is long, thick, and muscular, and can be swept from side 
 to side with enormous force, considering the size of the animal. 
 The legs have little or nothing to do with the act of swim- 
 ming. The fore-legs are pressed closely against the body, 
 and the hind-legs against each other. The latter act occa- 
 sionally as assistants in steering, but that is all. 
 
 Then there are the various Seals, whose hind-legs, flattened 
 and pressed together, act exactly like the tail of the fish, that 
 of the otter, the oar of the sculler, or the screw of the steamer. 
 Also, the eel, when swimming, uses exactly the same means, 
 its lithe body forming a succession of inclined planes ; so does 
 the snake, and so does the pretty little lampern, which is so 
 common in several of our rivers, and so totally absent from 
 others. 
 
 I can only now give a short description of the woodcut 
 which illustrates these points. 
 
 On the right hand Art is shown by the screw-blades of the 
 modern steamer. In the middle is the ordinary mode of 
 sculling a boat by an oar in the stern, and below it is the 
 rudder, which, like the sculling oar, may be used either for 
 propulsion or direction. 
 
 On the left hand we have three examples of the same
 
 THE WINDMILL AND AERIAL TOP. 21 
 
 mechanical powers as shown in Nature. The uppermost figure 
 represents a fish as in the act of swimming, the dotted lines 
 showing the movement of its tail, and the principle of the 
 wedge. In the middle is an otter, just preparing to enter the 
 water, and below is a seal, both of them showing the identity 
 of mechanism between themselves and the art of man. I need 
 not say that the mechanism of art is only a feeble copy of that 
 of nature, but nothing more could be expected. 
 
 WHILE we are on this subject I may as well mention two 
 more applications of the screw principle. The first is the 
 windmill, the sails of which are constructed on exactly the 
 same principle as the blades of the nautical screw. Only, as 
 they are pressed by the wind, and the mill cannot move, they 
 are forced to revolve by the pressure of the wind, just as the 
 screw of a steamer revolves when the vessel is being towed, 
 and the screw left at liberty. 
 
 Moreover, just as the modern screws have only two blades, 
 so, many modern windmills have only two sails, the expense 
 and friction being lessened, and the power not injured. 
 
 Again : some years ago there was a very fashionable toy 
 called the aerial top. It was practically nothing but a windmill 
 in miniature, rapidly turned by a string, after the manner of a 
 humming-top. The edges of the sails being turned down- 
 wards, the instrument naturally screwed itself into the air to a 
 height equivalent to the velocity of the motion. 
 
 A similar idea has been mooted with regard to the guidance 
 of balloons, or even to aerial voyaging without the assistance of 
 gas, but at present the weight of the needful machinery has 
 proved to be in excess of the required lifting power. 
 
 In fine, the application of the inclined plane, wedge, or 
 screw as a motive power, is so wide a subject that I must, with 
 much reluctance, close it with these few and obvious examples. 
 
 IT is worth while, by the way, to remark how curiously 
 similar are such parallels. I have already mentioned the very 
 evident resemblance between the water-boatman, the water- 
 beetles, and the human rower, the body of the insect being 
 shaped very much like the form of the modern boat. I must 
 now draw the attention of the reader to the similitude between
 
 22 
 
 NATURE S TEACHINGS. 
 
 the very primitive boat known by the name of Coracle, and 
 the common Whirl wig-beetle (Gyrinus natator}, which may be 
 found in nearly every puddle. The shape of the insect is 
 almost identical with that of the boat, and the paddle of the 
 
 WHIBLWIG BEETLE AIJD PADDLES. 
 
 CORACLE AND PADDLE. 
 
 coracle is an almost exact imitation of the swimming legs of 
 the whirlwig. And, as if to make the resemblance closer, 
 many coraclers, instead of using a single paddle with two 
 broad ends, employ two short paddles, shaped very much like 
 battledores.
 
 NAUTICAL. 
 
 CHAPTER III. 
 
 SUBSIDIARY APPLIANCES. PART I. 
 
 General Sketch of tbe Subject. The Mast of "Wood and Iron. Analogy between 
 the Iron Mast and the Porcupine Quill. The Iron Yard and its Shape pre- 
 figured by the same Quill. Beams of the Steam-engine. Principle of the 
 Hollo\? Tube in place of the Solid Bar. Quills and Bones of Birds. Wheat 
 Straws and Bamboos. Structure of the Boat. The Coracle, the Esquimaux 
 Boat, and the Bark Canoe. Framework of the Ship and Skeleton of the Fish. 
 Compartments of Iron Ship and Skull of Elephant. The Rush, the Cane, 
 and the Sugar-cane. " Stellate" Tissue and its Varieties. 
 
 HAYING now treated of the raft, the boat, the ship, and 
 their various modes of propulsion and guidance, we 
 come to the subsidiary appliances to navigation, if they may 
 be so called in lack of a better name. 
 
 First in importance is necessarily the mast ; and the yards, 
 which support the sails, are naturally the next in order. Then 
 there come the various improvements in the building of vessels ; 
 namely, the substitution of planks fastened on a skeleton of 
 beams for a mere hollowed log, and the subsequent invention 
 of iron vessels with their numerous compartments, giving 
 enormous strength and size, with very great comparative 
 lightness. 
 
 Then we come to the various developments of the ropes or 
 cables, by which a vessel is kept in its place when within reach 
 of ground, whether on shore or at the water-bed. Next come 
 the different forms of anchors which fasten a vessel to the bed 
 of the ocean, of grapnels by which she can be made fast to 
 the shore, or of " drags," which at a pinch can perform either 
 office, and can besides be utilised in searching for and hauling 
 up objects that are lying at the bottom of the sea.
 
 24 NATURE'S TEACHINGS. 
 
 Next we come to the boat-hook, which is so useful either as 
 a temporary anchor, or as a pole by which a boat can be pro- 
 pelled by pushing it against the shore or the bed of the water ; 
 and then to the " punt-pole," which is only used for the latter 
 purpose. 
 
 Lastly, we come to the life-belt and life-raft, which are now 
 occupying, and rightly, so much of the public attention. These 
 subjects will be treated in their order in the present chapter, 
 and I hope to be able to show the reader that in all these 
 points nature has anticipated art. i 
 
 I presume that most, if not all, of my readers are aware of 
 the rapidly extending use of iron in ship-building, not only in 
 the standing rigging, but in the material of the vessel. First 
 there came iron " knees," i.e. the angular pieces of wood 
 which strengthen the junctions of the timbers. Formerly 
 these were made of oak-branches, and, as it was not easy 
 to find a bough which was naturally bent at such an angle as 
 was required for a "knee," such branches were exceedingly 
 valuable. Iron, however, was then employed, and with the best 
 results. It was lighter than the wooden knee, was stronger, 
 could be bent at any angle, and took up much less space. 
 
 By degrees iron was used more and more, until vessels were 
 wholly made of that material. Then the masts, and even the 
 yards, were made of iron, and, strange as it may appear, were 
 found to be lighter as well as stronger than those made of 
 wood. Of course, the masts and yards were hollow, and it was 
 found by the engineers that in order to combine lightness with 
 great strength, the best plan was to run longitudinal ridges 
 along the inside of the tube. 
 
 A section of one of these masts is given at Fig. B, and 
 taken from the drawings of one of our largest engineering 
 firms. The reader will see that the mast is composed of rather 
 slight material, and that it is strengthened by four deep though 
 thin ribs, which run throughout its length. 
 
 "When I first saw this mast I was at once struck with the 
 remarkable resemblance between it and the quill of the Porcu- 
 pine. These quills, as all anglers know, are very light, and 
 of extraordinary strength when compared with their weight. 
 Indeed, they are so light that they are invaluable as penholders 
 to those who are obliged to make much use of their pen. I
 
 MASTS, YARDS, AND ENGINE-BEAMS. 
 
 25 
 
 have used nothing else for a very long time, and the drawing 
 of the Porcupine quill which is here given at Fig. A was 
 made from a small piece cut from the top of the penholder 
 which I have used for some fifteen years, and with which all 
 my largest and most important works were written, including 
 the large " Natural History," " Homes without Hands," " Man 
 and Beast," &c., &c. A portion of the same quill is also shown 
 of its real size. 
 
 If the reader will cut a Porcupine quill at right angles, 
 make a thin section of it, and place it under the microscope, or 
 even under an ordinary pocket lens, he will see that the 
 exterior is composed of a very thin layer of horny matter, 
 and the interior filled with a vast number of tiny cells, which 
 are formed much on the same plan as the pith of elder and 
 other plants. The analogies of the pith will be treated in 
 another page. 
 
 But were the quill merely a hollow tube filled with pith, it 
 would be too weak to resist the strain to which it is often 
 
 PORTION OF POBCUPIXE QUILL. 
 
 SECTION OF ENGINE BEAK. 
 
 COMPLETE QUILL. 
 
 IRON YAED AND YARD-ARM. 
 
 ENGINE BEAM. 
 
 SECTION OF PORCUPINE QUILL MAGNIFIED. 
 
 SECTION OF IRON MAST. 
 
 liable. Consequently it is strengthened by a number of inter- 
 nal ribs, composed of the same horny material as the outer coat, 
 and arranged in exactly the same way as those of the mast. 
 
 There are yet other points in the structure of the Porcupine 
 quill which might be imitated with advantage in the mast. 
 In the first place, the internal ribs are much more numerous
 
 26 NATURE'S TEACHINGS. 
 
 than those of the mast, but they are very much thinner, and 
 taper away from the base, where the greatest strain exists, to the 
 end, where they come to the finest imaginable edge. This 
 modification of structure enables the outer shell of the quill to 
 be exceedingly thin and light, and, moreover, gives to the 
 whole quill an elasticity which is quite wonderful, considering 
 its weight and strength. 
 
 Then, in the iron mast the exterior is quite smooth, whereas 
 in the Porcupine quill it is regularly indented, exactly on the 
 principle of the corrugated iron, which combines great strength 
 with great lightness. And I cannot but think that our iron 
 masts might be made both lighter and stronger if the shell 
 were thinner, the internal ribs made like those of the Porcu- 
 pine quill, and the shell corrugated instead of being quite 
 smooth. The internal cells of the quill are, of course, not 
 needed in the mast, as they are intended for nutrition, and not 
 for strength. 
 
 BEING on this subject, we may take the shape of the Porcu- 
 pine quill, and compare it with that of the ship's yard. It 
 will be seen that the two are so exactly similar in form that 
 the outline of one would answer perfectly well for the other. 
 The only perceptible difference is, that in the ship's yard both 
 ends are alike, whereas in the Porcupine quill the end which 
 is inserted in the skin is rounded and slightly bent, while the 
 other end is sharply pointed. 
 
 The principal point to be noticed in the form of both quill 
 and yard is, that they become thicker in the centre, that being 
 the spot on which the greatest strain comes, and which, in con- 
 sequence, needs to be stronger than any other part. While 
 holding and balancing the pole which Blondin uses to preserve 
 his balance when walking on the high rope, I was struck with 
 the fact that the pole, which is heavily weighted at each end, 
 had to be strengthened in the middle, exactly on the principle 
 of the Porcupine quill and the ship's yard. It could not, of 
 course, be thickened, as the hands could not grasp it, but it 
 had to be furnished with additional strengthening. And the 
 necessity of such strengthening is evident from the fact that 
 on one occasion the pole did break in the middle, so that any 
 one of less nerve and presence of mind must have been killed.
 
 QUILLS AND STRAW. 27 
 
 Bearing in mind, then, that in a rod or pole the centre is the 
 part which most requires to be strengthened, we can see, in 
 cases too numerous to mention, how art has followed, though 
 perhaps unconsciously, in the footsteps of nature. Take, for 
 example, the beam of a steam-engine, such as is given in the 
 sketch, and for which the great engine at Chatham acted as 
 model. The reader will observe that in this case the beam is 
 gradually thickened towards the centre, the ends, where the 
 strain is slightest, being comparatively small. 
 
 Another point also must be noticed. Equal strength could 
 have been obtained had the beam been solid, but at the expense 
 of weight, and consequent waste of power. Lightness is there- 
 fore combined with strength by making the beam consist of a 
 comparatively slight centre, but having four bold ridges, as 
 shown in the section given in the accompanying illustration. 
 This plan, as the reader will see, is exactly the same as that 
 which is adopted in the iron mast and porcupine quill, except 
 that the ridges are external instead of internal. The same 
 mode of construction is employed in ordinary cranes, the prin- 
 cipal beam of which is almost identical in form with that 
 of the engine, both being thickest in the centre, and both 
 strengthened with external ridges. 
 
 There are also other analogies between the hollow mast and 
 natural objects. Keeping still to the animal world, we find 
 the quill feathers of the flying birds to supply examples of the 
 combination of great strength with great lightness and very 
 little expenditure of material. Their wing bones, too, aro 
 hollow, communicating with the lungs, and are consequently 
 light as well as strong. 
 
 Passing to the vegetable world, we find a familiar example 
 of this structure in the common Wheat Straw. The ripe ear is 
 so heavy, when compared with the amount of material which 
 can be spared to carry it, that if the stalk were solid it would 
 give way under the mere weight of the ear. Moreover, the 
 full-grown corn has to endure much additional weight when 
 wetted with rain, and to resist much additional force when 
 bowed by the wind, so that a slight and solid stalk would be 
 quite inadequate to the task of supporting the ear. 
 
 The material of the stalk is therefore utilised in a different 
 manner, being formed into a hollow cylinder, the exterior of
 
 28 NATURE'S TEACHINGS. 
 
 which is coated with a very thin shell of flint, or " silex " as it 
 is scientifically termed. The result of this structure is that the 
 stem possesses strength, lightness, and elasticity, so as to be 
 equal to the burden which is laid upon it. 
 
 Then there is the common Bamboo, which is little more than 
 a magnified straw, being constructed in much the same manner, 
 and possessing almost the same constituents of vegetable matter 
 and silex. 
 
 Perhaps the most extraordinary of the tubal system is to be 
 found in the remarkable plant ol Guiana called by the natives 
 Ourah, and scientifically known by the name of Arundinaria 
 Schomburgkii. Like the bamboo, it grows in clusters, and has 
 a feathery top, which waves about in the breeze. But, instead 
 of decreasing gradually in size from the base upwards, the 
 Ourah, although it runs to some fifty feet in height, is 
 nowhere more than half an inch in diameter. The first joint 
 is about sixteen feet in length, and uniform in diameter 
 throughout. 
 
 It is scarcely thicker than ordinary pasteboard, and yet so 
 strong and elastic is it, that it can sustain with ease the weight 
 and strain of its feathery top as it blows about in the breeze. 
 The natives of certain parts of Guiana use this reed as a blow- 
 gun, and I have a specimen, presented to me by the late Mr. 
 Waterton, which is eleven feet in length. 
 
 So the reader will see that when engineers found that hollow 
 iron beams were not only lighter, but stronger than solid beams, 
 they were simply copying the hollow beams formed by Nature 
 thousands of years ago. 
 
 ANOTHER great improvement in ship-building now comes 
 before us. 
 
 We have already seen that the earliest boats were merely hol- 
 lowed logs, just as Robinson Crusoe is represented to have made. 
 But these had many disadvantages. They were always too 
 heavy. They were liable to split, on account of flaws in the 
 wood, and if a large vessel were needed, it was difficult to find 
 a tree sufficiently large, or to get it down to the water when 
 finished. 
 
 So the next idea was to build a skeleton, so to speak, of light 
 wooden beams, and to surround it with an outer clothing, or
 
 SKELETON OF FISH AND BOAT. 29 
 
 skin, if it may be so termed. As far as I know, tlie two 
 original types of this structure are the Coracle of the ancient 
 Briton, and the birch-bark Canoe of the North American 
 Indian, and it is not a little remarkable that both exist to the 
 present day, with scarcely any modification. 
 
 The Coracle has been already represented on page 22. It is, 
 perhaps, or was in its original form, the simplest boat in exist- 
 ence, next to the " dug-out." In the times of the very ancient 
 Britons, who were content with blue paint by way of dress, 
 and lived by hunting and fishing, the Coracle was a basin- 
 shaped basket of wicker-work, rather longer than wide, and 
 covered with the skin of a wild ox. This was sufficiently light 
 to be carried by one man, and sufficiently buoyant to bear him 
 down rapids, if he were a skilful paddler, and, of course, formed 
 a considerable step in civilisation. 
 
 The modern Coracle is identical in form, and almost in 
 material. The frame is still oval and basin-shaped, and made 
 of wicker, but the outer covering is not the same. An ox-hide 
 is an expensive article in these days, and, especially when 
 wetted, is very heavy. So the modern Coracle builder covers 
 the wicker skin with a piece of tarpaulin, which is much 
 cheaper than the ox-hide, much lighter, is equally water-tight, 
 and has the great advantage of not absorbing moisture, so that 
 it is as light after use as before. 
 
 The Esquimaux make a boat on very similar principles. It 
 is simply hideous in form, resembling a huge washing- tub in 
 shape, but, as it is only intended for the inferior beings called 
 women, this does not signify. 
 
 Best, most perfect, and most graceful of all such boats is the 
 Birch-bark Canoe of the North American Indians, whose shape 
 has evidently been borrowed from that of a fish. I have seen 
 many of these canoes, and have now before me several models 
 which are exactly like the originals, except in point of size. 
 Instead of being mere elongated bowls, like the coracle, they 
 are long and slender, swelling out considerably in the middle, 
 and coming to an almost knife-like edge at each end. Both stem 
 and stern are alike, so that the canoe can be paddled in either 
 direction, and, as one of the paddlers always acts as steersman, 
 no rudder is needed. 
 
 The mode of construction is perfectly simple. The labour is
 
 30 
 
 NATURE'S TEACHINGS. 
 
 divided between the sexes: the women cut large sheets of 
 bark from the birch-trees, scrape and smooth them, and then 
 sew them together, so as to form the outer skin, or " cloak" as 
 it is called, of the canoe. Meanwhile the men are making the 
 skeleton of strips of white cedar-wood, and binding them into 
 shape with thongs made of the inner bark of the same tree, 
 just like the "bass " of our gardeners. The "cloak" is then 
 gradually worked over the skeleton, sewn into its place, and 
 the canoe is finished. A figure of this canoe, as completed, is 
 given in the same illustration as that which represents various 
 forms of boat, page 7. 
 
 The last improvement is that which was caused by the 
 necessity for large vessels, when planks or iron plates were 
 fastened over the skeleton. But, in all these cases, the vessel 
 is built on the principle of the thorax of a vertebrate animal, 
 that of the whale or a fish being an admirable example. It only 
 needs to take the skeleton of a whale, turn it on its back, and 
 the ribs will be seen to form an almost exact reproduction of 
 those of any ship being built in the nearest dockyard. 
 
 RIBS OF FISH. 
 
 KIDS OF SHIP. 
 
 now before me the spine and ribs of a herring. The 
 fish was over-boiled, and the flesh fell off the bones as it was 
 being lifted out of the dish, leaving most of the ribs in their 
 places. When held with the spine downwards, and viewed 
 from one end, the resemblance to the framework of a ship is 
 absolutely startling, the ribs representing the beams, and the 
 spine taking the place of the keel. I have also before me a 
 sketch representing a section of a Fijian canoe, and it is 
 remarkable that even the very curve of the ribs of the herring 
 is reproduced in those of the canoe.
 
 SEPARATE COMPARTMENTS AND THEIR USE. 
 
 31 
 
 Whether the Fijians derived this peculiar and beautiful curve 
 from the ribs of a fish I cannot say, but think it very likely. 
 
 A STILL greater improvement in ship-building now comes 
 before us, and this also has been anticipated both in the animal 
 and vegetable kingdoms. There are so many examples of this 
 anticipation that I can only give one or two. 
 
 The improvement to which I refer is that which is now almost 
 universally employed in the construction of iron ships, namely, 
 the making the outer shell double instead of single, and dividing 
 it into a number of separate compartments. Putting aside the 
 advantage that if the vessel were stove, only one compartment 
 would fill, we have the fact that the ship is at the same time 
 
 TBAXSVER8E SECTION OF IBON SHIP. 
 
 Jim fl 1 
 
 STELLATE TISSUES. 
 
 LONGITUDINAL SECTION OP IBON SHIP. 
 
 enormously strengthened and very light in proportion to her 
 bulk. 
 
 Perhaps the best, and certainly the most obvious, example of 
 this principle in the animal world is to be found in the skull 
 of the Elephant. The enormous tusks, with their powerful 
 leverage, the massive teeth, and the large and weighty pro-
 
 32 NATURE'S TEACHINGS. 
 
 boscis, require a corresponding supply of muscles, and conse- 
 quently a large surface of bone for the attachments of these 
 muscles. Now, were the skull solid in proportion to its 
 requisite size, its weight would be too much for the neck to 
 endure, however short and sturdy it might be. The mode of 
 attaining expanse of surface, together with lightness of struc- 
 ture, is singularly beautiful. 
 
 Perhaps some of my readers may not be aware that the bone 
 of the skull consists of an outer and inner plate, with a variable 
 arrangement of cells between them. In many animals, such, 
 for example, as man, where the jaws are comparatively feeble, 
 and the teeth small and light, the size of the skull is practically 
 that of the brain, to which it affords a covering. The same 
 structure may be observed in the skull of the common 
 sparrow, where, as in man, the two bony plates are set almost 
 in contact. 
 
 But in the elephant these external and internal plates are 
 set widely apart, and the space between them is filled with 
 bony cells, much resembling those of a honeycomb. They are, 
 in fact, just the same cells as those which exist in the skull of 
 man and sparrow, but they are very much enlarged, and in 
 consequence give a large surface, accompanied with united 
 strength and lightness. 
 
 There are many other examples in the animal kingdom, but 
 our limited space will not allow them to be even mentioned. 
 
 As to the vegetable examples of this principle, they are so 
 multitudinous that only a very slight description can be given 
 of them. 
 
 I suppose that most boys have seen a " cane " (whether they 
 have felt it or not is not to the purpose), and some boys have 
 made sham cigars from pieces of cane. In either case they 
 must have noticed that the cane is not solid, but is pierced 
 with a vast number of holes, passing longitudinally through it, 
 and is, in fact, a collection of little tubes connected and bound 
 together by a common envelope. 
 
 The Sugar-cane, if cut across, is seen also to consist of mul- 
 titudinous cells, which, however, are not hollow, but filled with 
 the sweet liquid from which sugar is obtained by boiling. 
 Then there are many of our common English plants, like the
 
 STELLATE TISSUE. 33 
 
 ordinary rush or reed, which are very slight in diameter in 
 comparison with their length, and in which the cells are still 
 further strengthened and lightened by the projection of their 
 sides into a number of points which meet each other, and 
 leave interstices between them. This modification of the 
 cellular system is called " Stellate " (or star-like) Tissue, and 
 two examples of it are given in the illustration, one being 
 taken from the common rush, and the other from the seed- 
 coat of the privet. A very good specimen of stellate tissue 
 may be obtained by cutting a thin section of the white inner 
 peel of the orange.
 
 NAUTICAL. 
 
 CHAPTER IV. 
 
 SUBSIDIARY APPLIANCES. PART II. 
 
 The Cable and its Variations. Material of Cables. Hempen and Iron Cables, 
 and Elasticity of the latter. Natural Cables. The " Byssus" of the Pinna 
 and the common Mussel. The Water-snail and its Cable. A similar Cable 
 produced by the common White Slug. The Principle of Elasticity. 
 Elastic CaWe of the Garden Spider. Tendrilous Cables of the Pea and the 
 Bryony. The Vallisneria, and its Development through the Elastic Cable. 
 Proposed Submarine Telegraph Cable. The Anchor, Grapnel, and their 
 Varieties. Natural Anchors. Spicule of Synapta. The Grapnel, natural 
 and artificial. Ice-anchor and Walrus Tusks. The Mushroom Kedge. 
 The Flesh-hook. Eagle-claw. The Grapple-plant of South Africa. The 
 Drag. 
 
 A MONG the most important accessories to a ship are the 
 **- Cable, by which she can be anchored to the bed of the sea, 
 and the ropes called " warps," by which she can be fastened to 
 the land. 
 
 Perhaps my readers may not know the old riddle " How 
 many ropes are there on board a man-of-war ? " The non- 
 nautical individual cannot answer, but the initiated replies 
 that there are only three, namely, the man-rope, the tiller- 
 rope, and the rope's-end, all the others being "tacks," "sheets," 
 " haulyards," " stays," " braces," &c. 
 
 Formerly cables were always made of hemp, enormously 
 thick, and most carefully twisted by hand. Now, even in 
 small vessels, the hempen cable has been superseded by the 
 iron chain, and this for several reasons. 
 
 In the first place, it is much smaller in bulk, and therefore 
 does not occupy so much room. In the next place, it is even 
 lighter than the hempen cable of corresponding strength ; and, 
 in the third, its specific gravity i.e. its weight when com-
 
 THE PINNA AND THE MUSSEL. 
 
 35 
 
 pared with an equal bulk of water is so great, that when 
 submerged, it falls into a sort of arch-like form, and so attains 
 an elasticity which takes off much of the strain on the anchor, 
 and protects it from dragging. 
 
 WE will now look to Nature for Cables. 
 The natural cable which will first suggest itself is evidently 
 that of the Pinna Shell (Pinna pectinata), which fixes its shell 
 
 EGO OF DOG-FI3H. 
 
 PINNA. 
 
 WATEB-SNAIL ANCHORED 
 TO WATER-LILY LEAF. 
 
 ANCHORED BOAT. 
 
 to some rock or stone with a number of silk-like threads, spun 
 by itself, and protruding from the base, just as a vessel on a 
 lee shore throws out a number of cables. The threads which 
 compose the " byssus," as it is called, are only a few inches in 
 length, and apparently slight. They are, however, really 
 strong, and by acting in unison enable the shell, though some- 
 times two feet in length, to be held firmly to the rock. I may 
 here mention that they have been occasionally woven into 
 gloves, and other articles of apparel, to which their natural 
 soft grey-brown hue gives a very pleasing appearance. 
 
 A still more familiar instance of a natural marine cable is 
 given by the common Mussel, which can be found in thousands 
 on almost every solid substance which affords it a hold. Even 
 copper-bottomed ships are often covered with Mussels, all 
 clinging by their natural cables, and it is thought that the 
 cases which sometimes occur of being poisoned by eating 
 Mussels, or " musselled," as the malady is called by the sea- 
 faring population, are due to the fact that the Mussels have 
 
 D 2
 
 t 
 36 NATURE'S TEACHINGS. 
 
 anchored themselves to copper, and have in consequence 
 imbibed the verdigris. 
 
 PASSING from salt to fresh water, we come to a natural cable 
 which is very common, and yet, on account of its practical 
 invisibility, is almost unknown, except by naturalists. I refer 
 to the curious cable which is constructed by the common 
 Water-snail (Limncea stagnalis), which has already been 
 mentioned in its capacity of a boat. 
 
 This creature has a way of attaching itself to some fixed 
 object, such as a water-lily leaf, by means of a gelatinous 
 thread, which it can elongate at pleasure, and by means of 
 which it can retain its position in a stream, or in still water can 
 sink itself to the bottom, and ascend to the same spot. This 
 cable seems to be made of the same glairy secretion as that 
 which surrounds the egg-masses which are found so plentifully 
 on leaves and stones in our fresh waters, and, like that substance, 
 is all but invisible in the water, so that an inexperienced 
 eye would not be able to see it, even if it were pointed out. 
 
 Slight, gelatinous, and almost invisible in the water as is 
 this thread, its strength is very much greater than might be 
 supposed. Not only can a mollusc be safely moored in the 
 water by such a cable, but it can be actually suspended in the 
 air, as may be seen from a letter in Hardwicke's Science Gossip 
 for 1875, p. 190 : 
 
 "Last summer (September 29) I met with the following 
 unusual fact. In a green-house, from a vine-leaf which was 
 within a few inches of the glass ... a slug was hanging by 
 a thread, which was more than four feet in length, not unlike 
 a spider-web, but evidently much stronger. 
 
 " The slug was descending by means of this thread, and, as 
 the glutinous matter from the under part of the body was 
 drawn out by the weight of the creature, it was consolidated 
 into a compact thread by the slug twisting itself in the direc- 
 tion of the hands of a clock, the power of twisting being given 
 by the head, and the part of the body nearest the head being 
 turned in the direction of the twist. There was no tendency 
 to turn in the contrary direction. Evidently the thread 
 became hard as soon as it was drawn away from the body. 
 
 " By wetting the sides of slips of glass, I secured two speci- 
 

 
 PRINCIPLE OF ELASTICITY. 37 
 
 mens of the thread. In one of these, part was stretched, and 
 part quite loose, the latter appearing flat when seen through a 
 microscope. The thread, which was highly elastic, was 
 increased about three inches in a minute. The slug was white, 
 and about an inch and a half in length." 
 
 Now we come to the elastic system of the Chain Cable, and 
 find it anticipated in Nature in various ways. 
 
 One curious example was that of a Spider, which found its 
 wheel-like net in danger from a tempestuous wind. The Spider 
 descended to the ground, a depth of about seven feet, and, 
 instead of attaching its thread to a stone or plant, fastened it to 
 a piece of loose stick, hauled it up a few feet clear of the ground, 
 and then went back to its web. The piece of stick thus left 
 suspended acted in a most admirable manner, giving strength 
 and support, and at the same time yielding partly to the wind. 
 
 By accident the thread became broken, and the stick, which 
 was about as thick as an ordinary pencil, and not quite three 
 inches in length, fell to the ground. The Spider immediately 
 descended, attached another thread, and hauled it up as 
 before. In a day or two, when the tempestuous weather had 
 ceased, the Spider voluntarily cut the thread, and allowed the 
 then useless stick to drop. 
 
 A CURIOUS example of the elastic cable is seen in the egg-case 
 of the Dog-fish, which is given on page 35. The egg-case is 
 formed like that of the common skate, and has a projection 
 from each of its angles. But the projections, instead of being 
 mere flattened horns, are lengthened into long elastic strings, 
 tapering towards the ends, and twisted spirally, like the 
 tendrils of a grape-vine. 
 
 These tendril-like appendages twist themselves round sea- 
 weeds and other objects, and, on account of their spiral form, 
 can hardly ever be torn from their attachments. Sometimes 
 after a storm the egg is thrown on the shore, still clinging to 
 the seaweed, but to find an egg detached is very rarely done. 
 
 I have already mentioned the tendrils of the vine, and their 
 great strength. The reader may remember the corresponding 
 cases of the Pea and the Bryony, the latter being a most 
 remarkable example of the strength gained by the spiral form.
 
 38 NATURE'S TEACHINGS. 
 
 It clambers about hedges, is exposed to the fiercest winds, liaa 
 large and broad leaves, and yet such a thing as a Bryony being 
 blown off a hedge is scarcely, if ever, seen. I never saw an 
 example myself, though I have had long experience in hedges. 
 
 ANOTHER excellent example of this principle is found in the 
 Vallisneria plant, which of late years has become tolerably 
 familiar to us through the means of fresh-water aquaria, 
 though it is not indigenous to this country. 
 
 In this plant the elastic power of the spiral cable is beauti- 
 fully developed. It is an aquatic plant, mostly found in run- 
 ning waters, and has a most singular mode of development. 
 It is dioecious i.e. the male, or stamen-bearing, and the 
 female, or pistil -bearing flowers, grow upon separate plants. 
 
 It has to deposit its seeds in the bed of the stream, and yet it 
 is necessary that both sets of flowers should be exposed to the air 
 and sun before they become able to perform their several duties. 
 Add to this the fact that the male flower is quite as small in pro- 
 portion to the female as is the case with the lac and scale insects, 
 and the problem of their reaching each other becomes apparently 
 intricate, though it is solved in a beautifully simple manner. 
 
 Fertilisation cannot be conducted by means of insects, as is 
 the case with so many dioacious terrestrial plants, and it is 
 absolutely necessary that actual contact should take place 
 between them. This difficult process is effected as follows : 
 
 The female flowers are attached to a very long spiral and 
 closely coiled footstalk, and, when they are sufficiently 
 developed, the footstalk elongates itself until the flower rests 
 on the surface of the water, where it is safely anchored by its 
 spiral cable, the coils yielding to the wavelets, and keeping the 
 flower in its place. 
 
 Meanwhile the tiny male flowers are being developed at the 
 bottom of the river, and are attached to very short footstalks. 
 When they are quite ripe they disengage themselves from their 
 footstalks, and rise to the surface of the river. Being carried 
 along by the stream, they are sure to come in contact with the 
 anchored female flowers. This having been done, and the 
 seeds beginning to be developed, the spiral footstalk again coils 
 itself tightly, and brings the seeds close to the bed of the 
 stream, where they can take root.
 
 THE ANCHOR. 
 
 39 
 
 There are other numerous examples, of which any reader, even 
 slightly skilled in botany, need not be reminded, most of them 
 being, in one form or another, modifications of the leaf or the 
 petal, which, after all, are much the same thing. The vine 
 and passion-flower are, however, partial exceptions. 
 
 I may here mention that soon after the failure of the first 
 Atlantic telegraph cable, an invention was patented of a very 
 much lighter cable, enclosed in a tube of india-rubber, and 
 being coiled spirally at certain distances, so that the coils 
 might give the elasticity which constitutes strength. The 
 cable was never made, its manufacture proving to be too 
 costly ; but the idea of lightness and elasticity, having been 
 evidently taken from the spiral tendrils of the bryony, was 
 certainly a good one, and I should have wished to see it tried 
 on a smaller scale than the Atlantic requires. 
 
 As a natural consequence, after the cable comes the Anchor, 
 which in almost every form has been anticipated by Nature, 
 whether it be called by the name of anchor, kedge, drag, 
 or grapnel. 
 
 On the accompanying illustrations are shown a number of 
 corresponding forms of the Anchor, together with a few others, 
 which, although they may not necessarily be used in the 
 water, are nevertheless constructed on the same principle i.e. 
 for the purpose of grappling. 
 
 ONE of the most startling parallels may be seen on the right 
 
 ANCIENT AXCHOR. 
 
 8PICULES OP SYNAPTA. 
 
 hand of the illustration, the figure having been drawn from an 
 old Roman coin. On the other side of the same illustration
 
 40 
 
 NATURE S TEACHINGS. 
 
 may be seen an anchor so exactly similar in form, that the 
 outline of the one would almost answer for that of the other. 
 This object is a much-magnified representation of a spicule 
 which is found on the skin of the Synapta, one of the so-called 
 Sea-slugs, which are so extensively sold under the name of 
 Beche de Mer. It forms one of the curious group called the 
 Holothuridae. 
 
 Each of these anchors is affixed to a sort of open-worked 
 shield, as shown above, and on the left hand ; and it is a curious 
 fact that in the various species of Synapta the anchor is 
 rather different in form, and the shield very different in pattern. 
 They are lovely objects, and I recommend any of my readers 
 who possess a microscope to procure one. They need a power 
 of at least 150 diameters to show their full beauties. 
 
 An ordinary Grapnel is here shown, and in the corresponding 
 position on the opposite side is an almost exactly similar object, 
 except that it is double, having the grapnel at both ends of the 
 stem. This is a spicule of a species of sponge, and is one of the 
 vast numbers of which the sponge principally consists. 
 
 LEBNEXTOMA. 
 
 ECHnrococcus. BPONGE-SPICULE. 
 
 Next to the sponge-spicule is a still more perfect example 
 of a natural Grapnel. This is the head of an internal parasite 
 called Echinococcus, which holds itself in its position by means 
 of the circle of hooks with which the head is surrounded. 
 These hooks are easily detached, and have a curious resemblance 
 to the claw of the lion or tiger. 
 
 On the left-hand side is a representation of a parasitic crus- 
 tacean animal called Lernentoma, which adheres to various 
 fishes, and is mostly found upon the sprat, clinging to the gills 
 by means of its grapnel-shaped head. 
 
 On the right hand of the accompanying illustration is an ice- 
 anchor, copied from one of those which were taken out in the
 
 ICE-ANCHORS. 
 
 41 
 
 Arctic expedition of 1875. Opposite is the skull of tlie Walrus, 
 the tusks of which are said to be used for exactly the same 
 
 TUSKS OF WALRUS. 
 
 ICE-ANCHOR AND ICE-HOOKS. 
 
 purpose. Below are ice-hooks, also used for the same expedi- 
 tion. 
 
 The next illustration exhibits a butcher's hook and a common 
 porter's hook, by which he lifts sacks on his back ; and oppo- 
 
 SPONGE-SPICULE8. 
 
 BUTCHER'S HOOK. 
 
 PORTER'S HOOK. 
 
 site them are some sponge- spicules, the similarity of which 
 in form is so remarkable that the former might have been 
 copied from the latter. 
 
 OUR next sketch shows a remarkable example of similitude 
 in form. There are certain small anchors called Kedges, which 
 are very useful for mooring a boat where no great power of 
 
 MUSHROOM HEDGE. 
 
 resistance has to be overcome, and a large anchor would be 
 cumbersome. One of these is called, from its shape, the 
 " Mushroom Kedge," and is very useful, as, however it may be
 
 42 NATURE'S TEACHINGS. 
 
 dropped, some part of the edge is sure to take the ground. 
 This Kedge is shown on the right hand of the illustration, and 
 the Mushroom, from which its shape was borrowed, is seen on 
 the left. 
 
 . 
 
 WE now come to some more examples of the principle of 
 the Grapnel, some of which are applied to nautical, and others 
 to terrestrial objects. 
 
 EAGLE-CLAW. FLESH-HOOK. 
 
 The right-hand upper figure represents the " Flesh-hook," 
 used for taking boiled meat out of the caldron, so familiar to 
 us by the reference to it in Exodus xxvii. 3, and the still 
 better-known allusion to its office in 1 Samuel ii. 13, 14. In 
 the former passage, even the material, brass, which was really 
 what we now call bronze, is mentioned, and it is a curious fact 
 that all the specimens in the British Museum, from one of 
 which the drawing was taken, are made of bronze. I need 
 hardly state that the hollow handle is meant to receive a 
 wooden staff. 
 
 On comparing this figure with that of the Eagle's foot on 
 the opposite side, the reader cannot but be struck with the 
 exact resemblance between the two. Indeed, there is very 
 little doubt that the flesh-hook was intentionally copied from 
 the foot of some bird of prey. Perhaps the Osprey would have 
 furnished even a better example than the Eagle, the claws 
 being sharper and more boldly curved, so as to hold their 
 slippery prey the better. 
 
 ON the left hand of the next illustration is a figure of the 
 seed-vessel of the Grapple-plant of Southern Africa, drawn from 
 a specimen in my collection. The seed-vessel is several inches 
 in length, and the traveller who is caught by a single hook had 
 better wait for assistance than try to release himself. The stems 
 of the plant are so slender, and the armed seed-vessels so
 
 THE GRAPPLE-PLANT AND THE DRAG. 43 
 
 numerous, -that in attempting to rescue one portion of the 
 dress, another portion becomes entangled, and the traveller 
 gets hopelessly captured. Besides the hooks of the seed- 
 vessels, the branches themselves are armed with long thorns, 
 set in pairs. The scientific name of this plant is Uncinaria 
 procumbenSy the former word signifying " a hook," and the latter 
 " trailing." It is also known by the popular name of Hook- 
 plant. 
 
 GRAPPLE-PLANT. 
 
 In the late Kafir wars the natives made great use of this 
 and other plants with similar properties, their own naked, 
 dark, and oiled bodies slipping through them easily and un- 
 seen, while the scarlet coats of the soldiers were quickly 
 entangled, and made them an easy mark for the Kafir's spear. 
 In this way many more of our soldiers were killed by the spears 
 than by the bullets of their enemies. 
 
 Opposite to the Grapple-plant is shown the common Drag, 
 which is utilised for so many purposes. Generally it is 
 employed for recovering objects that have sunk to the bottom 
 of the water, and its use by the officers of the Humane Society 
 is perfectly well known, the Drag being sometimes affixed to 
 the end of a long pole, like the flesh-hook already described, 
 and sometimes tied to a rope. 
 
 It can also be used as an anchor, after the manner of a 
 kedge, and has been often employed in naval engagements for 
 the purpose of drawing two ships together, and preventing the 
 escape of the vessel which is being worsted. My relative, the 
 late Admiral Sir J. Harvey, K.B., used drags in this manner, 
 and secured two French ships, one on either side, namely, 
 L'Achille and Le Vengeur. The first was sunk, and the 
 second captured.
 
 NAUTICAL. 
 
 CHAPTER V. 
 
 SUBSIDIARY APPLIANCES. 
 
 PART III. THE BOAT-HOOK AND PUNT-POLE. THE LIFE-BUOY AND 
 PONTOON-RAFT. 
 
 The Boat-hook and its varied Uses. The Earth-worm and the Serpula. Micro- 
 scopic Boat-hooks. The Life-belt. Life-boats and their Structure. Uses 
 of Cork. Wine Corks made serviceable. The Life-collar. Portuguese 
 Man-of-war. Captain Boyton's Life-dress. The Life-raft. Victualling a 
 Yacht and Boat. The Janthina and its Air-vessels. Cask-pontoon Pot- 
 tery-raft and its Uses. 
 
 A S all rowing men know, an indispensable appliance to the 
 *-*- boat is the Boat-hook, which can be used either as a pole, 
 wherewith to push the boat along, or as a grapnel, by which 
 it can be drawn towards the shore or a ship. As the latter 
 portion has been discussed at the close of the preceding chapter, 
 we may proceed to the former. 
 
 Every one knows how a boat may be propelled by a pole pressed 
 against the bank or the bottom of the water, and that there are 
 certain boats, called punts, which are propelled in no other way. 
 
 Now, the punt-poles and boat-hooks, of which some examples 
 are given in the accompanying illustration, have long been 
 anticipated in Nature, there being many creatures which have 
 no other mode of progression; such, for example, as the 
 common Earth-worm, which pushes itself along by certain 
 bristles which project from the rings of which the body is 
 composed, and which have the power of extension and con- 
 traction to a wonderful extent. As, however, I shall advert 
 to these in another part of the work, I will content myself at 
 present with a single example, namely, the beautiful marine 
 worm known as the Serpula.
 
 PUNT-POLES. 
 
 45 
 
 This worm lives in a shelly tube, which is lined with a 
 delicate membrane, up and down which it passes with ease, 
 ascending slowly, but generally descending with such wonder- 
 ful rapidity that the eye cannot follow its movements. The 
 latter movement will be explained in a subsequent part of the 
 book, and we will at present only treat of the former. 
 
 If the creature be removed from the tube, and carefully 
 examined, a number of projections will be seen, in each of 
 which is a perforation. If the animal be pressed, a slight 
 glass-like bristle passes through the perforation, and can easily 
 
 PUSHING SPIKES OF SERPULA. 
 
 BOAT-HOOKS AND PUXT-POLES. 
 
 be removed. If properly treated, and placed under a high 
 power of the microscope, the tiny bristle resolves itself into 
 the remarkable object which is shown on the left hand of the 
 illustration. 
 
 It consists of a number of spear-like rods, each having a 
 straight shaft, and a curved and pointed tip, deeply barbed on 
 the inner portion of the curve. These curious bundles of 
 spicules can be protruded or retracted at pleasure, and, as they 
 are all directed backwards, it is evident that when they are 
 pushed against the sides of the tube, either the points or the 
 barbs must catch against the membrane which lines the tube, 
 and so propel the animal upwards. When it wishes to 
 descend, it uses another set of implements, and withdraws the 
 first within their sheaths. 
 
 This is exactly analogous to the mode of progression em- 
 ployed by punters, who, after they have placed the pole against 
 the bed of the stream, and run along the punt so as to push it 
 as fast as possible, immediately withdraw the pole, and take it 
 to the head of the punt, ready for another push. This, as the 
 reader will see, is exactly the plan pursued by the Serpula in 
 lengthening itself when it wishes to advance, and so to press
 
 46 NATURE'S TEACHINGS. 
 
 its spicules against the sides of its tube, and in shortening 
 itself and withdrawing the spicules ready for another push. 
 
 ANOTHER needful accessory of vessels now comes before us, 
 namely, the capability of forming rafts or life-belts, which will 
 float under any circumstances. Here, again, every human 
 invention of which I know has been anticipated by Nature. 
 Take, for example, the familiar instance of the cork life-belt 
 and the cork edgings of the life-boat. Both are constructed 
 on the same principle, i.e. the maintenance of cells which are 
 filled by air instead of water, and are impervious to the latter. 
 
 The material most used for this purpose is cork, and life- 
 belts constructed of it have long been in well- deserved use, the 
 cork -bark having the property of holding much air and ex- 
 cluding water. Many of our life-boats are furnished with a 
 broad and thick streak of cork, so that even if the boat be 
 filled with water and upset, she will right herself and swim. 
 I regret to say that many of the so-called " life-belts " which 
 are offered for sale ought rather to be called "death-belts," 
 they having been found to be filled with hay and straw, with 
 only a few shavings of cork just under the covering of the belt. 
 
 Indeed, so buoyant is this substance that a very efficient belt 
 can be made by stringing together three or four rows of ordinary 
 wine corks, and tying them round the neck like a collar. Under 
 these circumstances it is simply impossible to sink, and though 
 any one may collapse from exhaustion, drowning is almost out 
 of the question. The now well-known cork mattress, which is 
 used in many ships, is another example of the same principle. 
 
 Lately there has been invented a " life-collar," which 
 possesses similar advantages, but occupies less space when not 
 wanted. It is nothing more than a tube of caoutchouc, which 
 can be inflated at pleasure, and tied round the neck. The 
 ordinary life-belt goes round the waist, and needs much more 
 material without obtaining a better result, which is simply the 
 keeping of the mouth and nostrils out of the water. 
 
 Perhaps the most buoyant of living beings is the Portuguese 
 Man-of-war (Physalis pelagicus], which floats on the surface of 
 the ocean like a bubble. It can at pleasure distend itself with 
 air and float, or discharge the air and sink. 
 
 Now, there is a very remarkable swimming dress, which,
 
 BUOYS AND LIFE-BOATS. 47 
 
 though not entirely invented, was at least perfected by Captain 
 Boyton, and which, as it enabled the wearer to cross from 
 France to England under rather unfavourable circumstances, 
 is clearly a most valuable invention. 
 
 PORTUGUESE MAN-OF-WAB. CAPTADf BOYTON's LIFE-DBESS. 
 
 Whether the inventor knew it or not I cannot say, but the 
 Boyton life-dress is simply a modification of the Physalis, 
 being capable of dilatation with air at will. 
 
 So much for the individual life-belt, and we will now pass to 
 those which are intended to sustain more than one individual. 
 It has almost invariably been found that when a ship has been 
 wrecked on a rock, or stove in by the sea, that, although there 
 may be plenty of boats, there is great difficulty in getting them 
 into the water rightly. 
 
 Now, if parts of the ship itself could be made of materials 
 which could not be sunk except by enormous pressure, and 
 which might be released by a touch if the vessel were sinking, 
 it is evident that many lives would be saved which have now 
 been lost. 
 
 And if such movable parts of the vessel were supplied with 
 water and provisions in air-tight cases, there is no doubt that 
 the number of " missing " ships would be very greatly dimi- 
 nished. I remember an instance where a yacht was " hung 
 up " on a mud-bank, whence there was no escape, for twenty- 
 four hours, and there was one sandwich on board to be divided 
 among the owner, two men, and a boy. Of course the boy had 
 the sandwich, and the men sustained themselves as well as they 
 could with tea, of which there was, fortunately, a canister on 
 board. As it was, they were some thirty-six hours without food. 
 
 After such an experience the owner had special lockers made 
 in the yacht and her boat, containing biscuit, potted meats, water,
 
 48 NATURE'S TEACHINGS. 
 
 wine, spirits, tobacco, tea, an " etna " for heating the water, 
 and matches. Of course these were on a smaller scale in the 
 boat ; but several thick rugs were also stowed away, in case of 
 being separated from the yacht at night. It so happened that 
 they were never needed ; but the sense of security which they 
 imparted was worth ten times the expense and trouble, which 
 included a careful inspection of all the stores before each 
 voyage. 
 
 In Nature there is just such a raft as is needed, capable of 
 carrying a heavy freight, and which cannot be upset. And 
 it is rather remarkable that it has been unconsciously imitated 
 in various parts of the world. 
 
 JANTHINA AND AIR-RAFT. CASK-PONTOON. 
 
 POTTERY-BAFT OF THE NILE. 
 
 This is the singular apparatus attached to the Violet Snail 
 (Janthina communis), which is common enough in the Atlantic, 
 and derives its name of Violet-shell from its beautiful colour. 
 The chief interest, however, centres in the apparatus which is 
 popularly called the " raft," and which sustains the shell and 
 eggs. It is made of a great number of air-vessels, affixed 
 closely to each other, and by the curious property of bearing its 
 cargo slung beneath it instead of being laid upon it. 
 
 Beneath the raft are the eggs, or rather, the capsules which 
 contain the eggs, and at one end is the beautiful violet shell 
 itself. The floating power of the raft is really astonishing, 
 and even in severe tempests, when it is broken away from the 
 animal, the raft continues to float on the surface of the waves, 
 bearing its cargo with it. 
 
 On the opposite side of the illustration are two examples of 
 rafts constructed so exactly on the same principle as that of the 
 Violet Snail, that they both might have been borrowed from it. 
 
 The upper is the kind of raft which has often been con- 
 structed by sailors when trying to escape from a sinking 
 ship, or by soldiers when wishing to convey troops across a
 
 THE CASK-PONTOON. 49 
 
 river, and having no regular " pontoons " at hand. It is made 
 simply by lashing a number of empty casks to a flooring of 
 beams and planks. 
 
 The amount of weight which such a structure will support is 
 really astonishing, as long as the casks remain whole, and to 
 upset it is almost impossible. Even cannon can be taken 
 across wide expanses of water in perfect safety, and there is 
 hardly anything more awkward of conveyance than a cannon, 
 with its own enormous and concentrated weight, and all the 
 needful paraphernalia of limber, ammunition (which may not 
 be wetted, and of immense weight), horses, and men. 
 
 Yet even this heterogeneous mass of living and lifeless weight 
 can be carried on the cask-raft, which is an exact imitation of 
 the living raft of the Violet Snail. 
 
 BENEATH the cask-pontoon is to be seen a sketch of a very 
 curious vessel which is in use on the Nile, and I rather think 
 on the Ganges also, though I am not quite sure. It is formed 
 in the following manner : 
 
 In both countries there are whole families who from genera- 
 tion to generation have lived in little villages up the river, and 
 gained their living by making pottery, mostly of a simple 
 though artistic form, the vessel having a rather Iftng and 
 slender neck, and a more or less globular body. 
 
 When a man has made a sufficient number of these vessels, 
 he lashes them together with their mouths uppermost, and 
 then fixes upon them a simple platform of reeds. The papyrus 
 was once largely used for this purpose, but it seems to be 
 gradually abandoned. 
 
 He thus forms a pontoon exactly similar in principle with 
 the cask-pontoon which has just been described. Then, taking 
 his place on his buoyant raft, he floats down the river until he 
 comes to some populous town, takes his raft to pieces, sells the 
 pots and reeds, and makes his way home again by land.
 
 WAE AND HUNTING. 
 
 CHAPTER I. 
 
 THE PITFALL, THE CLUB, THE SWORD, THE SPEAR AND 
 DAGGER. 
 
 Analogy between War and Hunting. The Pitfall as used for both Purposes. 
 African Pitfalls for large Game, and their Armature for preventing the P^scapa 
 of Prey. Its Use in this Country on a miniature scale. Mr. Waterton's 
 Mouse-trap. Pitfall of the Ant-lion, and its Armature for preventing the 
 Escape of Prey. The Club and its Origin. Gradual Development of the 
 Weapon. The "Pine-apjle" Club of Fiji. The Game of Pallone and the 
 " Bracciale." The Irish Shillelagh. Clubs and Maces of Wood, Metal, 
 or mixed. The Morgenstern. Ominous Jesting. Natural Clubs. The 
 Durian, the Diodon, and the Horse-chestnut. The Sword, or flattened and 
 sharpened Club. Natural and artificial Armature of the Edge. The Sword- 
 grass, , Leech, and Saw-fish. Spears and Swords armed with Bones and 
 Stones. The Spear and Dagger, and their Analogies. Structure of the 
 Spear. The Bamboo as a Weapon of War or Hunting. Singular Combat, 
 and its Results. 
 
 THE two subjects which are here mentioned are practically 
 one, the warfare being in the one case carried on against 
 mankind, and in the other against the lower animals, the 
 means employed being often the same in both cases. 
 
 THE PITFALL. 
 
 ONE of the simplest examples of this double use is afforded 
 by the PITFALL, which is employed in almost every part of the 
 world, and, although mostly used for hunting, still keeps its 
 place in warfare. 
 
 On the right hand of the accompanying illustration is shown 
 a section of the Pitfall which is so commonly used in Africa for 
 the capture of large game. It is, as may be seen, a conical 
 hole, the bottom of which is armed with a pointed stake. 
 Should a large animal fall intc the pit, the shape of the sides
 
 PITFALLS. 
 
 51 
 
 forces it upon the stake, by which it is transfixed. Even 
 elephants of the largest size often fall victims to this simple 
 trap. It is only large enough to receive the fore-legs and 
 chest, but that is quite sufficient to cause the death of the 
 animal, the stake penetrating to the heart. 
 
 Many a hunter has fallen into these traps, and found great 
 difficulty in escaping, while some have not escaped at all. 
 Indeed, in many parts of Southern Africa, when part of one 
 
 PITFALL OF ANT-LION FOR CATCHING INSECTS. AFRICAN PITFALL FOE CATCHING LARGE GAME. 
 
 tribe is about to visit another, the pitfalls are always unmasked, 
 lest the intended guests should fall into them. 
 
 Even without the spike, the elephant would scarcely be able 
 to save itself, owing to its enormous weight, unless helped out 
 by its comrades before the hunters came up. Indeed, many 
 pitfalls are intentionally made for this purpose, and are of a 
 different shape, i.e. about eight feet in length and four in 
 breadth. 
 
 In those which are made for the capture of the giraffe, the pit 
 is very deep, and the place of the stake is occupied by a trans- 
 verse wall, which prevents the feet of the captive from touching 
 the ground, and keeps it suspended until the hunters can come 
 and kill it at leisure. 
 
 Even in Belgium and our own country the pitfall is in use. 
 "When the field-mice were devastating the districts about 
 Liege some years ago, their ravages were effectually checked 
 by pitfalls, in which they were caught by bushels, the pitfalls 
 being simple holes some two feet deep, and made wider below 
 than above. 
 
 The late Mr. Waterton contrived to rid his garden of field- 
 mice by pitfalls constructed on the same principle, though 
 more permanent. Finding that the little animals made great 
 
 E 2
 
 52 NATURE'S TEACHINGS. 
 
 havoc among his peas just as they were starting out of the 
 ground, he buried between the rows a number of earthen 
 pickle-jars, sinking them to the level of the ground. He then 
 rubbed the inside of the neck with bacon, and left them. The 
 mice stooped down to lick off the bacon, fell into the jars, and, 
 the neck being narrow and the sides slippery, they could not 
 get out again. 
 
 ON the left hand of the illustration is the section of a pitfall 
 made by the well-known Ant-lion (Mynneleo), of which 
 there are several species. The history of this wonderful insect 
 is so familiar to us that it need not be repeated at length. 
 Suffice it to say that it digs conical pitfalls in loose sandy soil, 
 and that it places itself at the bottom of the pit, securing the 
 insect victims with its jaws just as the larger animals are 
 secured by the stake of the human hunter. 
 
 It makes no false cover, as does the human hunter, but it 
 always chooses soil so loose that if an insect approach the edge, 
 the sand gives way, and it goes sliding down into the pit, 
 whence its chance of escape is very small, even were there no 
 deadly jaws at the bottom ready to receive it. 
 
 THE CLUB. 
 
 THE simplest of all offensive weapons is necessarily the 
 CLUB. At first, this was but a simple stick, such as any 
 savage might form from a branch of a tree by knocking off 
 the small boughs with a stone or another stick. Such clubs 
 are still used in Australia, and I have several in my collection. 
 
 Then the inventive genius of man improved their destructive 
 power by various means. The most obvious plan was to add 
 to the force of its blow by simply making one end much thicker 
 and heavier than the other. This is done in the "Knob- 
 kerry " of Southern Africa, ani it is worthy of remark that in 
 Fiji a weapon exists so exactly like the short knob-kerry of 
 Africa, that an inexperienced eye would scarcely be able to 
 distinguish between them. 
 
 The next plan was to arm the enlarged head with pro- 
 jecting pieces or spikes, sometimes cut out of the solid wood, 
 and sometimes artificially inserted. The " Shillelagh " of 
 Ireland is a simple example of this kind of club. One of the
 
 CLUBS. 
 
 53 
 
 best and most elaborate examples of this sort of weapon is the 
 "Pine-apple " Club of Fiji, a figure of which may be seen in 
 the illustration, drawn from a specimen in my collection. 
 
 It is made in the most ingenious manner from a tree which 
 is trained for the purpose. There are certain trees belonging 
 to the palm tribe which possess "aerial" roots, i.e. subsidiary 
 roots, which surround the trunk at some distance from the 
 ground, and assist in supporting it. Some trees have no central 
 root, and are entirely upborne by the aerial roots, while others 
 have both. 
 
 One of these latter is selected, and when it is very young is 
 bent over and fastened to the ground almost at right angles, as 
 shown in the illustration. "When it has grown to a sufficient 
 age it is cut to the requisite length, the central root is sharp- 
 ened to a point, and the aerial roots are also cut down in such 
 
 POLLEN OF HOLLYHOCK. 
 HOBSE-CHESTNUT. 
 
 WOODEN AND METAL CLUBS. 
 
 a way that they radiate very much like the projections on a 
 pine-apple. This is really an ingenious weapon, for if the long 
 and sharpened end should miss its aim, the projections would 
 be tolerably sure to inflict painful if not immediately dangerous 
 injuries. 
 
 As the pine-apple is so well known, I have given in the 
 opposite side of the illustration a figure of the Durian, a large 
 Bornean fruit, which is covered with projections almost identical 
 in appearance with those of the pine-apple club, and almost 
 equally hard and heavy. 
 
 Perhaps some of my readers may have heard of the grand 
 Italian game of Pallone, the " game of giants," as it has been
 
 54 NATURE'S TEACHINGS. 
 
 called. The ball, which is a large and rather heavy one, 
 weighing more tha twice as much as a cricket-ball, is struck 
 with a wooden gauntlet reaching nearly half-way up the fore- 
 arm. The original gauntlet was cut entirely out of the solid 
 wood, and exactly resembled the exterior of the Durian. The 
 modern gauntlet, however, has the spikes fixed separately into 
 a wooden frame, so that they can be replaced if broken in the 
 course of the game. The principle, however, is identical in all 
 three cases. The technical name of this gauntlet is Bracciale. 
 
 The next improvement was to add still further to the destruc- 
 tive powers of the club by arming it with stones, so as to make 
 it harder and heavier. Sometimes a stone is perforated, and 
 the end of the club forced into it. Sometimes the stone is 
 lashed to the club, and sometimes a hole is bored in the club, 
 and the stone driven into it. This kind of club, made of a sort 
 of rosewood, may be found among some of the tribes inhabiting 
 the district of the Essequibo. 
 
 The next improvement was to make the weapon entirely of 
 metal, and such clubs are plentiful in every good collection of 
 arms. There was, for example, the common mace, which was 
 used for the purpose of stunning an adversary clothed in 
 armour which the sword could not penetrate. As this, how- 
 ever, was nothing more than an ordinary wooden club executed 
 in iron, we need not produce examples. 
 
 Other and more complicated forms were soon made, and 
 were wonderfully valuable until the rapidly improving fire- 
 arms kept combatants at a distance, and rendered a hand-to- 
 hand fight almost impossible. 
 
 Three examples of such clubs are given in the illustration, 
 and are taken from Demmin's valuable work called " Weapons 
 of War." 
 
 The upper left-hand specimen is called Morgen stern, i.e. 
 Morning Star. It is a large, heavy wooden ball studded with 
 steel spikes, and affixed to a handle usually some six or seven 
 feet, but sometimes exceeding eleven feet, in length. It was 
 chiefly used by infantry when attacking cavalry, the long shaft 
 enabling the foot-soldier to be tolerably sure of dealing the 
 cavalier or his horse a severe blow, while himself out of reach 
 of the latter's sword. 
 
 Behind it is another Morgenstern in which there is an
 
 THE MORGEXSTEKX. 55 
 
 improvement, the armed ball being furnished at the end with 
 a spike, so that it could be used either as a mace or a spear. 
 
 The commonest form of the Morning Star is shown below, 
 and is thus described by Demmin : 
 
 " This mace had generally a long handle, and its head bristled 
 with wooden or iron points. It was common among the ancients, 
 for many museums possess several fragments of these weapons 
 belonging to the age of bronze. 
 
 " The Morning Star was very well known and much used in 
 Germany and Switzerland. It received its name from the 
 ominous jest of wishing the enemy 'good morning' with the 
 Morning Star when they had been surprised in camp or city. 
 
 " This weapon became very popular on account of the 
 facility and quickness with which it could be manufactured. 
 The peasants made it easily with the trunk of a small shrub 
 and a handful of large nails. It was also in great request 
 during the wars of the peasantry which have devastated 
 Germany at different times, and the Swiss arsenals possess 
 great numbers of them." 
 
 One of these primitive weapons may be seen in the lower 
 figure of the illustration. 
 
 Sometimes the spiked ball was attached to a chain, and 
 fastened to the end of a handle varying greatly in length, 
 measuring from two to ten feet. One of these weapons may be 
 seen in the Guildhall of London, being held by one of the 
 celebrated giants. 
 
 IF the reader will now turn to the illustration on page 53, he 
 will see that on the right of the Durian there are two spherical 
 objects covered with spikes. The upper is the pollen of the 
 Hollyhock, and the lower the common Horse- chestnut. The 
 reader will see that these are precisely similar in form to the 
 spiked balls of the Morgenstern, whether they be used at the 
 end of a staff or slung to a chain. There are many similar 
 examples in the vegetable kingdom which will doubtless 
 suggest themselves to the reader, but these are amply sufficient 
 for this purpose. 
 
 Then, in the animal world, the curious Diodons, sometimes 
 called Urchin-fishes, or Prickly Globe-fishes, are good ex- 
 amples. These fishes are covered with sharp spines, and, as
 
 56 NATURE'S TEACHINGS. 
 
 they have the power of swelling their bodies into a globular 
 form, the spikes project on all sides just like those of the 
 pollen, or chestnut. There is a specimen in my collection, 
 which, if the tail and fins were removed, and a cast taken in 
 metal, would make a very good Morgenstern ball. 
 
 THE SWORD. 
 
 THE next improvement on the club was evidently to flatten 
 it, and sharpen one or both edges, so as to make it a cutting as 
 well as a stunning implement in fact, the club was changed 
 into a SWORD. 
 
 A GOOD example of this weapon in its simplest form is the 
 wooden sword of Australia, now an exceedingly rare weapon. 
 
 SWORD-GRASS MAGNIFIED. SHARK-TOOTH SWORD OF MANGAIA. 
 
 It looks like a very large boomerang, but is nearly straight, and 
 is made from the hard, tough wood of the gum-tree. Travellers 
 say that the natives can cut off a man's head with this very 
 simple weapon. 
 
 I just missed obtaining one of these swords from a man-of- 
 war, but, unfortunately, a few hours before my arrival the 
 zealous first lieutenant had ordered a large collection of savage 
 weapons to be thrown overboard, among which were several 
 Australian swords. 
 
 Finding that the edges were not sufficiently sharp, and were 
 liable to break, the maker next turned his attention to arming 
 them with some substance harder than wood. Various materials 
 were used for this purpose, some of which will be mentioned.
 
 PRIMITIVE SWORDS. 57 
 
 One of these is given in the illustration, and is taken from a 
 specimen in my collection. It is made of wood, rather more 
 than two feet in length, and would in itself be an insignificant 
 weapon but for its armature. 
 
 This consists of a number of sharks' teeth, which are fixed 
 along either side, and are a most formidable apparatus, each 
 tooth cutting like a lancet-blade, and not only being very sharp, 
 but having their edges finely notched like the teeth of a saw. 
 I have a series of these weapons in my collection, some being 
 curved, some straight, and one very remarkable weapon having 
 four blades, one straight and long blade in the centre, and three 
 curved and short blades springing from the handle towards the 
 point. 
 
 Opposite the shark-tooth sword is an object which might 
 almost be taken for a similar weapon, but is, in fact, nothing 
 but a common grass-blade, such as may be found in any of our 
 lanes. I suppose that most of my readers must at some time 
 have cut their fingers with grass, and the reason why is shown 
 in the illustration, which represents a much-magnified blade of 
 grass. The edges of the leaf are armed with sharp teeth of 
 flint, set exactly like those of the sword, with their points 
 directed towards the tip of the blade. The whole of the under 
 surface of the blade is thickly set with similar but smaller 
 teeth, arranged in the same manner. I have just brought a 
 blade of grass from a lane near my house, and when it was 
 placed under the half-inch power of the microscope, the resem- 
 blance to the sword was absolutely startling to some spectators 
 who came to look at it. 
 
 As if to make the resemblance closer, many savage weapons 
 are edged with flat stones, flint chips, or pieces of obsidian, so 
 that the flint teeth of the grass are exactly copied by the flint 
 edgings of the sword. The old Mexican swords were nearly all 
 edged with obsidian, as is seen in the lower right-hand figure 
 of the next illustration. I possess a number of obsidian flakes 
 which were intended for that purpose, but do not appear to have 
 been used. 
 
 The second figure from the top represents the head of a spear 
 similarly armed, and I possess a small Australian implement in 
 Avhich the flakes of obsidian are set only on one side, so that 
 the instrument can be used as a rude saw.
 
 58 
 
 NATURE S TEACHINGS. 
 
 Between these two weapons is a spear-head armed with 
 shark-teeth. I have a very remarkable weapon of this kind, 
 made in Mangaia. It is eleven feet in length, and, besides 
 being armed with a double row of sharks' teeth nearly to the 
 handle, it has three curved blades similarly armed, set at dis- 
 
 SWORD-GRASS. 
 LEECH JAW. 
 SAW-FISH. 
 
 SPEARS AND SWORD ARMED WITH 
 OBSIDIAN AND SHABKS* TEETH. 
 
 tances of about two feet, and projecting at right angles. Thus, 
 if the foe were missed with the point of the spear, he would 
 probably be wounded by one of the blades. 
 
 The upper figure represents a weapon where the natural bone 
 of the sting-ray has been used as the point. 
 
 On the opposite side are seen three natural objects similarly 
 armed. The uppermost is another species of sword-grass, like 
 that which has already been described. 
 
 Next comes a magnified view of one of the three cutting 
 instruments of the leech, showing the serrated teeth set along 
 its edge, by means of which it produces the sharply-cut wounds 
 through which it sucks the blood. 
 
 The last figure represents the head of the common Saw-fish, 
 in which a vast number of flat and sharply-edged teeth are set 
 upon the blade-like head. The fish has been observed to use 
 this weapon just as the Mangaian uses his sword-spear. It 
 dashes among a shoal of fish, sweeps its head violently back- 
 wards and forwards, and then, after they have dispersed, picks 
 up at its leisure the dead and disabled. 
 
 THE SPEAR AND THE DAGGER. 
 
 IT is tolerably evident that the invention of the spear and 
 dagger must have been nearly, if not quite, contemporaneous 
 with that of the club. I place these weapons together because
 
 PRIMITIVE SPEARS. 59 
 
 there is great difficulty in assigning to either of them the pre- 
 cedence, the spear being but a more or less elongated dagger, 
 and the dagger a shortened spear. 
 
 As a good example of this fact, I have in my collection a 
 number of spears and daggers belonging to the Fan tribe of 
 Western Africa. In every case the weapons correspond so 
 closely with each other, that if the daggers were attached to 
 shafts they would exactly resemble the spears, and if the spears 
 were cut off within a few inches of the head, they would be 
 taken for daggers. 
 
 I may here mention that as this part of the subject merely 
 involves the employment of a pointed or thrusting weapon, 
 instead of the club or sword, both of which are used for 
 striking, the question of poison, barbs, and sheaths will be 
 treated on another page. 
 
 The primary origin of the Spear is probably the thorn, as a 
 savage who had been wounded by a thorn would easily pass to 
 the conclusion that a thorn of larger size would enable him to 
 kill an enemy in war, or an animal in hunting. Anything of 
 sufficient dimensions, which either possessed a natural point or 
 could be sharpened into a point, would be available for the pur- 
 pose of the hunter or warrior. 
 
 Accordingly we find that such objects as the beak of the 
 heron or stork, the sharp hind-claw of the kangaroo, the bone 
 of the sting-ray, the beak of the sword-fish, and many similar 
 objects, are employed for the heads of spears, or used simply as 
 daggers. 
 
 As to artificial spears, nothing is easier than to scrape a stick 
 to a point, and then, if needful, to harden it in the fire. This 
 is, indeed, one of the commonest forms of primitive spears, and 
 I have in my collection many examples of such weapons. 
 Another simple form of this weapon is that which is made by 
 cutting a stick or similar object diagonally. 
 
 Hollow rods such, for example, as the bamboo are the 
 best for this purpose. I have now before me a cast of a most 
 interesting weapon discovered by Colonel Lane Fox. It is the 
 head of a spear, and is formed from part of the leg-bone of a 
 sheep. At one end there is a simple round hole, which acted 
 as a socket for the reception of the shaft, and the other end is 
 cut away diagonally, so as to leave a tolerably sharp point.
 
 60 NATURE'S TEACHINGS. 
 
 As to the bamboo, it has a great advantage in the thinness of 
 its walls, and the coating of flinty substance with which it is 
 surrounded, and which gives its edges a knife-like sharpness. 
 Indeed, so very sharp is the silex, that splinters of bamboo are 
 still used as knives, and with them a skilful operator can cut up 
 a large hog as expeditiously as one of our pork-butchers could 
 do with the best knife that Sheffield produces. 
 
 I possess several of these weapons, and formidable arms of 
 offence they are. If the reader can imagine to himself a tooth- 
 pick, a foot or more in length, made from bamboo instead of 
 quill, and having its edges nearly as sharp as a razor, he can 
 realise the force of even so simple a weapon. In the case of the 
 bamboo, too, celerity of manufacture has its value, for any one 
 can make a couple of spears in less than as many minutes. All 
 he has to do is to cut down a joint of bamboo transversely, and 
 then with a diagonal blow of his knife at the other end to form 
 the point. 
 
 The force of such a weapon may be inferred from a remarkable 
 combat that took place some sixty years ago, when the roads 
 were not so safe as they are at present. 
 
 A gentleman, who happened to be a consummate master of 
 the sword, was going along the highway at night, and was 
 attacked by two footpads, he having no weapon but a bamboo 
 cane. 
 
 One of them he temporarily disabled by a severe kick, and 
 then turned to the other, whom he found to be pretty well as 
 good a swordsman as himself, and to possess a good stick 
 instead of a slight cane. The footpad soon discovered the dis- 
 crepancy of weapons, and with a sharp blow smashed the cane 
 to pieces, leaving only about eighteen inches in his antagonist's 
 hand. 
 
 Almost instinctively Baron sprang under the man's 
 
 guard, and dashed the broken cane in his face. The footpad 
 staggered with a groan, put his hands to his face, and ran 
 away, followed by his companion, who did not desire another 
 encounter with such an antagonist. When the victor reached 
 his destination, he found that the footpad's face must have been 
 torn to pieces, for the clefts of the split bamboo were full of 
 scraps of skin, flesh, and whisker hair. 
 
 It is worthy of notice that the combination of the club and
 
 THE PATOO. 61 
 
 the dagger is common to savage and civilised life, as may be 
 seen by reference to the illustration in page 53, where the 
 wooden club of savage warfare and the metal club and maces of 
 civilisation are alike armed with a piercing as well as a bruising 
 apparatus. Mostly the dagger is on the head of the mace or 
 battle-axe, but, in some cases, the end of the handle acts as the 
 dagger, and the head as the axe or mace. 
 
 A very good example of this formation is found in the wooden 
 battle-axe, or "Patoo," of New Zealand, a weapon which has 
 been long superseded by modern fire-arms. A specimen in my 
 possession is rather more than five feet in length. The head is 
 just like that of an ordinary axe, while the handle tapers gra- 
 dually to the end, where it terminates in a sharp spike. In 
 actual combat the point was used much more than the axe.
 
 WAR AND HUNTING. 
 
 CHAPTER II. 
 
 POISON, ANIMAL AND VEGETABLE. PEINCIPLE OF THE BARB. 
 
 Poison as applied to Weapons. Its limited Use. Animal and Vegetable Poisons. 
 Animal Poisons. The Malayan Dagger, or Kris, and two Modes of poisoning 
 it. The Bosjesmans and their Arrows. Snake Poison and its Preparation. 
 The Pseudo-barb. The Poison-grub, or N'gwa. Simple Mode of Prepara- 
 tion, and its terrible Effects. Vegetable Poisons. The Upas of Malacca. 
 The Wourali Poison of Tropical America. Mode of preparing the various 
 Arrows. The Fan Tribe of West Africa, and their poisoned Arrows. Sub- 
 cutaneous Injection. Examples in Nature. The Poison-fang of the Serpent. 
 Sting of the Bee. Tail of the Scorpion. Fang of the Spider. Sting of 
 the Kettle. Exotic Nettles and their Effects. The Barb and its Develop- 
 ments. The " Bunday " of Java. Reversed Barbs of Western Africa. 
 Tongans and their Spears. The Harpoon and Lernentoma, or Sprat-sucker. 
 The Main Gauche, or Brise-e"pee. 
 
 A NOTHER advance, if it may so be called, lay in increasing 
 *"*- the deadly effect of the weapons by arming them with 
 poison. 
 
 Without the poison, it was necessary to inflict wounds which 
 in themselves were mortal ; but with it a comparatively slight 
 wound would suffice for death, providing only that the poison 
 mixes with the blood. It is worthy of notice that cutting 
 weapons, such as swords and axes, seldom, if ever, have been 
 envenomed, the poison being reserved for piercing weapons, 
 such as the dagger, the spear, and the arrow. 
 
 ANIMAL POISONS. 
 
 PERHAPS the most diabolical invention of this kind was the 
 Venetian stiletto, made of glass. It came to a very sharp point, 
 and was hollow, the tube containing a liquid poison. When 
 the dagger was used, it was driven into the body of the victim, 
 and then snapped off in the wound, so that the poison was ablo 
 to have its full effect.
 
 WEAPONS OF THE BOSJESMAN. 63 
 
 Such poisons are of different kinds, and invariably animal or 
 vegetable in their origin. Taking the animal poisons first, we 
 come to the curious mode of poisoning the Malayan dagger, or 
 " Kris." The blade of the weapon is not smooth, but is forged 
 from very fibrous steel, and then laid in strong acid until it is 
 covered with multitudinous grooves, some of them being often 
 so deep that the acid has eaten its way completely through the 
 blade. 
 
 Among some tribes the kris is poisoned by being thrust into 
 a putrefying human body, and allowed to remain there until 
 the grooves are filled with the decaying matter. It is also said 
 that if the kris be similarly plunged into the thick stem that 
 grows just at the base of the pine-apple, the result is nearly the 
 same. 
 
 As a rule, however, the Arrow is generally the weapon which 
 is poisoned, and a few examples will be mentioned of each kind 
 of poisoning. 
 
 The two most formidable animal poisons are those which are 
 made by the Bosjesmans of Southern Africa. Their bows are 
 but toys, and their arrows only slender reeds. But they arm 
 these apparently insignificant weapons with poison so potent, 
 that even the brave and bellicose Kafir warrior does not like to 
 fight a Bosjesman, though he be protected by his enormous shield. 
 
 There are two kinds of animal poison used by the Bosjesmans. 
 The first is made from the secretion of the poison-glands of the 
 cobra, puff-adder, and cerastes. Knowing the sluggish nature 
 of snakes in general, the Bosjesman kills them in a very simple 
 manner. He steals cautiously towards the serpent, boldly sets 
 his foot upon its neck, and cuts off its head. The body makes 
 a dainty feast for him, and' the head is soon opened, and the 
 poison-glands removed. 
 
 By itself, the poison would not adhere to the point of the 
 weapon, and so it is mixed with the gummy juice of certain 
 euphorbias, until it attains a pitch-like consistency. It is then 
 laid thickly upon the bone point of the arrow, and a little strip 
 of quill is stuck into it like a barb. The object of the quill is, 
 that if a man, or even an animal, be wounded, and the arrow 
 torn away, the quill remains in the wound, retaining sufficient 
 poison to insure death. I have a quiverful of such arrows in 
 my collection.
 
 64 NATURE'S TEACHINGS. 
 
 That arrows so armed should be very terrible weapons is 
 easily to be imagined, but there is another kind of poison which 
 is even more to be dreaded. This is procured from the innocent- 
 looking, but most venomous, Poison-grub. It is called N'gwa by 
 the Bosjesmans, and is the larval state of a small beetle. When 
 the arrow is to be poisoned, the grub is broken in half, and the 
 juices squeezed upon the arrow in small spots. 
 
 Both Livingstone and Baines give full and graphic accounts 
 of the horrible effect produced by this dread poison, which, as 
 soon as it mixes with the blood, drives the victim into raging 
 madness. A lion wounded by one of these arrows has been 
 known nearly to tear himself to pieces in his agonies. M. 
 Baines was good enough to present me with the N'gwa grub in 
 its different .stages, together with an arrow which has been 
 poisoned with its juices. 
 
 The Bosjesmans are themselves so afraid of the weapon, that 
 they always carry the arrows with the points reversed, the 
 poisoned end being thrust into the hollow reed which forms 
 the shaft of the arrow. Not until the arrow is to be discharged 
 does its owner place the tip with its point uncovered. 
 
 VEGETABLE POISONS. 
 
 WE now come to the Vegetable Poisons, the two best known 
 of which are the Upas poison of Borneo, and the Wourali of 
 South America. It is rather remarkable that in both these 
 cases the arrows are very small, and are blown through a hollow 
 tube, after the manner of the well-known " Puff-and-dart " toy 
 of the present day. 
 
 The Upas poison is simply the juice of the tree, and it does 
 not retain its strength for more than a few hours after it has 
 been placed on the arrow-points. A supply of the same liquid 
 is therefore kept in an air-tight vessel made of bamboo, the 
 opening being closed by a large lump of wax kneaded over it at 
 the mouth. One of these little flasks, taken from a specimen in 
 my collection, is seen on the extreme right of the illustration. 
 
 The Wourali poison owes all its power to its vegetable ele- 
 ment, though certain animal substances are generally mixed 
 with it. The principal ingredient is the juice of one of the 
 strychnine vines, which is extracted by boiling, and then care- 
 fully inspissated until it is about the consistency of treacle.
 
 POISONED WEAPONS. 
 
 65 
 
 This poison differs from the Upas in the fact that it retains its 
 potency after very many years, if only kept dry. I have a 
 number of arrows poisoned with the Wourali. They were given 
 to me by the late Mr. Waterton, who procured them in 1812, 
 and even in the present year (1875) they are as deadly as when 
 they were first made. 
 
 A bundle of these tiny arrows, surmounted by the little 
 wheel which is used to guard the hand from being pricked, is 
 seen next to the Bornean poison- flask. 
 
 SF.RPENT-FANG. BEE-STING. INJECTING 
 
 SCORPION-STING. SYRINGE. 
 
 SETTLE-STING. SPIDER-FANG. 
 
 POISONED ARROWS 
 
 AND 
 POISON-FLASK. 
 
 Beside these little arrows, which are only about ten inches in 
 length, very much larger arrows are used both for war and 
 hunting, and are propelled by the bow, and not with the breath. 
 Many of these arrows are nearly six feet in length. In all, the 
 head is movable fitting quite loosely into a socket, so that 
 when an animal is struck and springs forward, the shaft is 
 shaken off, to be picked up by the hunter, and fitted with 
 another point, while the poisoned head remains in the wound. 
 
 Another kind of poison, also of a vegetable origin, is used 
 by the Fan tribe. The arrows are mere little slips of bamboo, 
 and are propelled by a slight crossbow. But the poison is so 
 potent, that even these tiny weapons produce a fatal effect. 
 
 Nearly in the centre of the illustration is seen a rather 
 curiously formed syringe, with an extremely long and slender
 
 66 NATURE'S TEACHINGS. 
 
 tip. This is a recently invented instrument, used for the pur- 
 pose of subcutaneous injection i.e. of injecting any liquid 
 under the skin. It is mostly employed for injecting opium 
 and other drugs of similar qualities, for the purpose of obtain- 
 ing relief from local pain. The slender spike-like point is 
 hollow, and ends in a sharp tip, formed like the head of a 
 lance. Just below the head there is a little hole, communi- 
 cating with the interior of the tube. 
 
 The mode of operatir* It 1 simple enough. The syringe i 
 filled with the drug, and the point introduced under the skin 
 at any given spot. Pressure on the piston then forces out 
 the liquid, and causes it to mix with the blood. 
 
 NATURAL ANIMAL POISONS. 
 
 Now, both in the animal and vegetable worlds may be found 
 several examples of an apparatus which acts in exactly the 
 same manner. 
 
 The first is the poison-fang of the Serpent, a specimen of 
 which is given on the left hand of the illustration. This 
 fang answers in every respect to the syringe above mentioned. 
 The long and slender fang is hollow, and answers to the pipe of 
 the syringe. It communicates at the base with a reservoir of 
 liquid poison, which answers to the body of the syringe, and 
 there is a little hole, or rather slit, just above the point, which 
 allows the poison to escape. 
 
 When the serpent makes its stroke, the base of the fang is 
 driven against the reservoir, so that the liquid is urged 
 through the hollow tube, and forced into the wound. Even in 
 large serpents these fangs are very small. I have now before 
 me some fangs of the cobra, puff-adder, rattlesnake, and viper, 
 and it is astonishing how small and slender are these most deadly 
 weapons. The figure in the illustration is much magnified, in 
 order to show the aperture at the base, where communication 
 is made with the interior of the fang. As the exit hole is on 
 the upper curve of the fang, it is not visible in the figure. 
 
 Next to the serpent's fang is a representation of the Bee- 
 sting, the poisonous reservoir being seen at the base, and 
 having attached to it the tiny thread-like gland by which the 
 poison is secreted. 
 
 In the centre is seen the tail of a Scorpion, with its hooked
 
 VEGETABLE POISON'S. 67 
 
 sting. The last joint is formed just like the serpent's fang, 
 being hollow, having a sharp point with a slit near the end, 
 and a poison reservoir in the rounded base. When the 
 scorpion attacks an enemy, it strikes violently with the tail, 
 and the force of the blow drives out the poison just as is done 
 with the serpent's fang. 
 
 At the bottom of the illustration is shown the poison-fang of 
 a Spider, which, as the reader may see, is formed just on the 
 principle of the scorpion-sting. 
 
 NATURAL VEGETABLE POISONS. 
 
 So much for animal poisons. We will now pass to the 
 vegetable world. 
 
 Of the vegetable sting-bearers none are more familiar to us 
 than the Nettle, three species of which inhabit this country. 
 The two commonest are the Great Nettle ( Urtica diceced) and the 
 Small Nettle (Urtica urens), and both of them are armed with 
 venomous stings, which cause the plants to be so much dreaded. 
 The structure of these stings is very simple, and can be 
 made out with an ordinary microscope, or even a good pocket 
 lens. Each of these stings is, in fact, a rather elaborately con- 
 structed hair, hollow throughout its length, coming to a point 
 at the tip, and having the base swollen into a receptacle con- 
 taining the poisonous juice. When any object such, for 
 example, as the human hand touches a nettle, the points of 
 the stings slightly penetrate the skin, and the hair is pressed 
 downwards against the base, so that the poison is forced 
 through the hole- 
 One of these hairs is shown in the left-hand bottom corner 
 of the illustration. 
 
 Even the tiny stings of our English nettles are sufficiently 
 venomous to cause considerable pain, and, in some cases, even 
 to affect the whole nervous system. But some of the exotic 
 nettles are infinitely more formidable, and are, indeed, so 
 dangerous that, when they are grown in a botanical garden, 
 a fence is placed round them, so as to prevent visitors even 
 from touching a single leaf. 
 
 The two most dreaded species are called Urtica heterophylla 
 and Urtica crenulata. The former is thought to be the more 
 dangerous of the two, and a good idea of its venomous qualities
 
 68 NATURE'S TEACHINGS. 
 
 may be gathered from an account of an adventure with Urtica 
 crenulata. The narrator is M. L. de la Tour. 
 
 " One of the leaves slightly touched the first three fingers of 
 my left hand ; at the time I only perceived a slight pricking, 
 to which I paid no attention. This was at seven in the morn- 
 ing. The pain continued to increase, and in an hour it became 
 intolerable ; it seemed as if some one were rubbing my fingers 
 with a hot iron. Nevertheless, there was no remarkable 
 appearance, neither swelling, nor pustules, nor inflammation. 
 
 " The pain spread rapidly along the arm as far as the arm- 
 pit. I was then seized with frequent sneezing, and with a 
 copious running at the nose, as if I had caught a violent cold in 
 the head. About noon I experienced a painful attack of cramp 
 at the back of the jaws, which made me fear an attack of tetanus. 
 I then went to bed, hoping that repose would alleviate my 
 suffering, but it did not abate. On the contrary, it continued 
 nearly the whole of the following night ; but I lost the con- 
 traction of the jaws about seven in the evening. 
 
 " The next morning the pain began to leave me, and I fell 
 asleep. I continued to suffer for two days, and the pain 
 returned in full force when I put my hand into water. I did 
 not finally lose it for nine days." 
 
 There is another of these formidable nettles, called in the 
 East by a name which signifies " Devil's Leaf," and which is 
 sufficiently venomous to cause death. There is but little doubt, 
 however, that in the present instance, if a larger portion of 
 the body say the whole arm instead of three fingers, had 
 been stung, death would have ensued from the injury. 
 
 THE BARB. 
 
 WE now come to another improvement, or rather addi- 
 tion, in the various piercing weapons. Sometimes, as in the 
 case of the dagger or the hand-spear, it was necessary that 
 when a blow had been struck the weapon should be easily 
 withdrawn from the wound, so as not to disarm the assailant, 
 and to enable him to repeat the stroke if needful. But in the 
 case of a missile weapon, such as a javelin or an arrow, it was 
 often useful, both in war and hunting, to form the head in 
 such a way that when it had once entered it could scarcely be 
 withdrawn. For this purpose the Barb was invented, taking
 
 PRINCIPLE OF THE BARB. 69 
 
 different forms, according to the object of the weapon and the 
 nationality of the maker. 
 
 As in this work I prefer to show the gradual development of 
 human inventions, I shall take my examples of barhs entirely 
 from the weapons of uncivilised nations, six examples of which 
 are given in the accompanying illustration, and five of them 
 being drawn from specimens in my collection. 
 
 BAEBED WEAPONS. 
 
 The upper left-hand figure is rather a curious one, the position 
 of the barbs being nearly reversed, so that they serve to tear 
 the flesh rather than adhere to it. The opposite figure repre- 
 sents an arrow with a doubly barbed point. It is chiefly used 
 for shooting fish as they lie dozing on or near the surface of the 
 water, but it is an effective weapon for ordinary hunting pur- 
 poses, and, as the shaft is fully five feet in length, is quite 
 formidable enough for war. 
 
 The left-hand bottom figure represents a very remarkable 
 instrument, for it can hardly be called a weapon, and is, in fact, 
 the head of a policeman's staff. It is peculiar to Java, and is 
 called by the name of " Bunday." As may be seen by refer- 
 ence to the illustration, the head of the Bunday is formed of 
 two diverging slips of wood. To each of these is lashed a row 
 of long and sharp thorns, all pointing inwards, and the whole 
 is attached to a tolerably long shaft. 
 
 When a prisoner is brought before the chief, a policeman 
 stands behind him, armed with the Bunday, and, if the man 
 should try to escape, he is immediately arrested by thrusting 
 the weapon at him, so as to catch him by the waist, neck, or 
 arm, or a leg. Escape is impossible, especially as in Java the 
 prisoner wears nothing but his waist-cloth. 
 
 A weapon formed on exactly the same principle was used in. 
 the fifteenth and sixteenth centuries, and was employed for
 
 70 
 
 NATURE S TEACHINGS. 
 
 dragging knights off their horses. It was of steel instead of 
 wood, and the place of the thorns was taken by two movable 
 barbs, working on hinges, and kept open by springs. When 
 a thrust was made at the knight's neck the barbs gave way, so 
 as to allow the prongs to envelop the throat, and they then 
 sprang back again, preventing the horseman from disengaging 
 himself. This weapon is technically named a "catchpoll." 
 
 An illustration of one of these weapons will be given on 
 another page. 
 
 The right-hand central figure is an arrow from Western 
 Africa. In a previous illustration (page 65) a head of one of 
 these arrows is given on rather a larger scale, so as to show 
 the very peculiar barbs. These are of such a nature that when 
 they have well sunk into the body they cannot be withdrawn, 
 but must be pushed through, and drawn out on the opposite 
 side. This is drawn from one of my own specimens. 
 
 In some cases, with an almost diabolical ingenuity, the 
 native arrow-maker has set on a couple of similar barbs, 
 directed towards the point, so that the weapon can neither be 
 pushed through nor drawn back. One of these arrows is shown 
 in the illustration, but, for want of space, the artist has placed 
 the opposing barbs too near each other. 
 
 In some parts of Southern Africa a similar weapon was 
 used for securing a prisoner, the barbed point being thrust 
 down his throat and left there. If it were pushed through the 
 neck it killed him on the spot, and if it remained in the 
 wound the man could not eat nor drink, and the best thing 
 for him was to die as soon as he could. 
 
 With similar ingenuity, the Tongans and Samoans made 
 their war-spears with eight or nine barbs, and, before going 
 into action, used to cut the wood almost through between 
 each barb, so that when the body was pierced, the head, with 
 several of the barbs, was sure to break off and leave a large 
 portion in the wound. In Mariner's well-known book there is 
 an admirable account of the mode employed by a native 
 surgeon for extracting one of these spear-heads. So common 
 was this weapon that every Tongan gentleman carried a many- 
 barbed spear about five feet long, and used it either as a 
 walking-stick or a weapon. It is needless to say that this 
 spear is almost an exact copy of the tail-bone of the Sting-
 
 THE HARPOON. 71 
 
 ray. A dagger made of this bone was used in the Pelew 
 Islands in 1780, but seemed to be rather scarce. 
 
 The left-hand central figure is a Fijian fish-spear of four 
 points, and the last figure on the right hand represents a large 
 four-pronged spear of Borneo. Both these weapons are in my 
 collection. 
 
 ANOTHER example of a weapon where a large and powerful 
 barb is needful is the Harpoon. As the harpoon is used in 
 capturing the whale, the largest and most powerful of living 
 mammalia, it is evident that a barb which will hold such a prey 
 must be rather peculiarly made. The head and part of the 
 shaft of the harpoon are shown in the right-hand figure of the 
 accompanying illustration. 
 
 The left-hand figure represents a curious parasitic crustacean, 
 popularly called the Sprat- sucker, because it is usually found on 
 sprats. It affixes itself mostly to the eye, the deeply barbed 
 head being introduced between the eye and the socket. In 
 
 LERNEXTOMA. 
 
 some seasons this remarkable parasite is quite plentiful, while 
 in others scarcely a specimen can be found. Its total length is 
 slightly under an inch, and its scientific name is Lernentoma 
 Spratti. 
 
 The following graphic account of some prototypic weapons 
 belonging to a marine worm is given by Mr. Rymer Jones, 
 and is well worthy of perusal, not only for the vividness of the 
 description, but for its exact accuracy : 
 
 " Here is a Polynoe, a curious genus, very common under 
 stones at low water on our rocky shores. 
 
 " It is remarkable on several accounts. All down the back we 
 discover a set of oval or kidney-shaped plates, which are called 
 the back-plates (dorsal elytra) ; these are flat, and are planted 
 upon the back by little footstalks, set on near the margin of 
 the under surface : they are arranged in two rows, overlapping 
 each other at the edge. These kidney-shaped shields, which 
 can be detached with slight violence, are studded over with 
 little transparent oval bodies, set on short footstalks, which are,
 
 72 NATURE'S TEACHINGS. 
 
 perhaps, delicate organs of touch. The intermediate antennae, 
 the tentacles, and the cirrhi or filaments of the feet, are 
 similarly fringed with these little appendages, which resemble 
 the glands of certain plants, and have a most singular 
 appearance. 
 
 " If we remove the shields, we discover, on each side of the 
 body, a row of wart-like feet, from each of which project two 
 bundles of spines of exquisite structure. The bundles, expand- 
 ing on all sides, resemble so many sheaves of wheat, or you may 
 more appropriately fancy you behold the armoury of some 
 belligerent sea-fairy, with stacks of arms enough to accoutre a 
 numerous host. 
 
 "But, if you look closely at the weapons themselves, they 
 rather resemble those which we are accustomed to wonder at in 
 missionary museums, the arms of some ingenious but bar- 
 barous people from the South Sea Islands, than such as are 
 used in civilised warfare. Here are long lances, made like 
 scythe-blades, set on a staff, with a hook on the tip, as if 
 to capture the fleeing foe, and bring him within reach of 
 the blade. Among them are others of similar shape, but 
 with the edge cut into delicate slanting notches, which run 
 along the sides of the blade like those on the edge of our 
 reaping-hooks. 
 
 " These are chiefly the weapons of the lower bundle ; those 
 of the upper are still more imposing. The outermost are short 
 curved clubs, armed with a row of shark's teeth to make them 
 more fatal ; these surround a cluster of spears, the long heads 
 of which are furnished with a double row of the same appendages, 
 and lengthened scimitars, the curved edges of which are cut 
 into teeth like a saw. 
 
 " Though a stranger might think I had drawn copiously on 
 my fancy for this description, I am sure, with your eye upon 
 what is on the stage of the microscope at this moment, you will 
 acknowledge that the resemblances are not at all forced or 
 unnatural. To add to the effect, imagine that all these weapons 
 are forged out of the clearest glass instead of steel ; that the 
 larger bundles may contain about fifty, and the smaller half as 
 many each ; that there are four bundles upon every segment, 
 and that the body is co mposed of twenty-five such segments, 
 i<nd you will have a tolerable idea of the garniture and
 
 THE SWORD- BREAKER. 73 
 
 armature of this little worm, which grubs about in the mud at 
 low-water mark." 
 
 Somewhere between the fifteenth and sixteenth centuries a 
 sort of anomalous weapon was in use, namely, a dagger, with a 
 
 PAST OF WASP-STING. MAIN GAUCHE. 
 
 number of very deep and bold barbs. It was not, however, 
 employed for offence, but for defence, and was used in the 
 " rapier and dagger " mode of fighting, when the dagger, 
 which was held in the left hand, was employed to parry the 
 thrusts of the rapier, which was held in the right. From the 
 mode of holding it, the weapon was called " Main Gauche." 
 
 Sometimes the blade was quite plain, and, indeed, an ordinary 
 dagger answered the purpose. But in most cases the Main 
 Gauche was made for this special purpose, and was furnished 
 either with strong diverging projections, or with a series of deep 
 notches, so that the sword of the enemy might be caught in 
 them and broken. In consequence of this use these notched 
 or guarded weapons were also called by the name of Brise-epee, 
 or Sword-breaker. 
 
 The resemblance between this weapon and the blade of a 
 wasp's sting can be seen at a glance. There is another form of 
 the Brise-epee which is so strangely like the cutting apparatus 
 of one of the saw-flies, that an outline sketch of the one would 
 answer very well for the other.
 
 WAR AND HUNTING. 
 
 CHAPTER III. 
 
 PROJECTILE WEAPONS AND THE SHEATH. 
 
 Propulsive Power. The Pea-shooter and its Powers. An Attack repulsed. Clay 
 Bullets. Puff and Dart. The Sumpitan of Borneo, and its Arrows. The 
 Zarahatana or Pucunha of South America, and its Arrows. The Air-gun. 
 Modern Fir<-arms. The Choetodon, or Archer-h'sh. The Pneumatic Rail- 
 way. The Throwinqj-stick and its Powers. Australians, Et-quimaux, and 
 New Caledonians. Principle of the Sheath. Waganda Spears. Sheathed 
 Piercing Apparatus of the Gnat, Flea, and Bomhylius. Indian Tulwar and 
 Cat's Claw. The Surgeon's Lancet, and Piercing Apparatus of the Gad-fly 
 and Mosquito. 
 
 WE will now take some of the analogies between Projectile 
 "Weapons of Art and Nature, selecting those in which the 
 propulsive power is air or gases within a tube. Whether the 
 weapon be a blow-gun, an air-gun, or a firearm of any descrip- 
 tion, the principle is the same. We will take them in succes- 
 sion, choosing first those of the simplest and most primitive 
 character. 
 
 Taking ourselves as examples, and looking upon the toys of 
 children as precursors of more important inventions, we find 
 that the simplest and most primitive of projectiles is the 
 Pea-shooter, so familiar to all boys. 
 
 Insignificant as is the little tin tube, and small as are the 
 missiles which are propelled through it, the blow which can be 
 struck by a pea properly shot is no trifle. At college I have 
 seen a night attack upon an undergraduate's rooms successfully 
 repelled by a pea- shooter made for the nonce of a glass tube, 
 the owner of the rooms having a taste for chemicals, and 
 possessing a fair stock of the usual apparatus. Though the 
 assaulted rooms were on the top set, and the assailants began 
 their storming approaches below, the peas were too much
 
 THE SUMPITAN OF BORNEO. 75 
 
 for the stones, taking stinging effect on the hands and 
 faces, and preventing any good aim being taken at the 
 windows. Only two panes of glass were broken through a 
 siege that lasted for several hours. 
 
 There is another toy which is a development of the pea- 
 shooter, and carries a small clay bullet instead of a pea. When 
 the tube is quite straight and the balls fit well, the force of this 
 missile is very great, as it can be used for killing small birds. 
 Indeed, such an instrument is largely employed by the native 
 hunters in procuring humming-birds for the European market. 
 These weapons are generally lined with metal in this country, 
 but a simple bamboo tube is sufficient for the native hunters. 
 
 A still further improvement occurs where the place of the 
 bullet is taken by a small dart or arrow, which is usually made 
 to fit the bore by having a tuft of wool, or some similar 
 substance, at the butt. The arrow is aimed at a target, and 
 the toy is popularly known as "Puff and Dart." 
 
 With us this apparatus is only a toy, but in several parts of 
 the world it becomes a deadly weapon, namely, in Borneo and 
 over a large part of tropical America. In both cases, the 
 arrows are poisoned, as has already been mentioned when 
 treating of poisoned weapons. 
 
 THE first and best known of these weapons is the dreaded 
 Sumpitan, or Blow-gun, of Borneo, the arrows of which are 
 poisoned with the deadly juice of the upas-tree. Here I may 
 as well mention that the scientific name of the upas-tree is 
 Antiaris toxicaria. It belongs to a large group of plants, all of 
 which have an abundance of milk-like and sometimes poisonous 
 juice. We are most of" us familiar with the old story of the 
 upas-tree and its deadly power, and how the tree stood in a 
 valley, in which nothing else could live, and that condemned 
 criminals might compound for their inevitable fate by ven- 
 turing into the valley of death and bringing back a flask of 
 the dread poison. Even birds were supposed to be unable to 
 fly over the valley, but to fall into it, being poisoned by the 
 exhalations of the tree. 
 
 Now, there is a saying that there is no smoke without fire, 
 and though this account is evidently incredible, it is not 
 altogether without foundation. In Java, as in many other
 
 70 NATURE'S TEACHINGS. 
 
 parts of the world, there are low-lying places where carbonic 
 acid gas exudes from the earth, and no living creature can 
 exist in them. Even in this country scarcely a year passes 
 without several deaths occurring from inhalation of the same 
 fatal gas, which has collected in some disused excavation. 
 That there is, therefore, a deadly valley in Jata may be true 
 enough, and it is also true that the juice of the upas-tree is 
 poisonous when it mixes with the blood. But the two have no 
 connection with each other, and, so far from the upas-tree 
 poisoning the valley by its exhalations, it could not exist in 
 such an atmosphere. 
 
 Now for the Sumpitan and the arrows. The former is a tube, 
 some seven feet in length, with a bore of about half an inch in 
 diameter, and often elaborately inlaid with metal. I have one 
 in which the whole of the mouthpiece is brass, and the other 
 end of the weapon has been fitted with a large spear-head, 
 exactly on the principle of the bayonet. 
 
 The arrows are very slight, and, in order to make them fit 
 the tube, are furnished at their bases with a conical piece of 
 soft wood. In themselves they would be almost useless as 
 weapons, but when the poison with which their points are 
 armed is fresh, these tiny arrows, of which sixty or seventy 
 are but an ordinary handful, carry death in their points. 
 Though they have no great range, they are projected with 
 much force, and with such rapidity that they cannot be 
 avoided, their slender shafts being almost invisible as they pass 
 through the air. 
 
 THE second weapon is the still more dangerous blow-gun of 
 tropical America, called Zarabatana, or Pucunha, according to 
 the locality. Some of these tubes measure more than eleven 
 feet in length, and through them the arrow can be propelled 
 with wonderful force. I have often sent an arrow to a distance 
 of a hundred yards, and with a good aim. 
 
 A native, however, can send it much farther, knack, and not 
 mere capacity of lung, supplying the propelling power, just 
 as it is with the pea-shooter. When the arrow is properly 
 blown through the zarabatana a sharp " pop " ought to be 
 heard, like the sound produced by a finger forced into a 
 thimble and quickly withdrawn, or a cork drawn from a bottle.
 
 THE AIR-GUN. 77 
 
 As to seeing the diminutive arrow in its flight, it is out of 
 <he question, and no agility can be of the least use in avoiding 
 it. One of my friends, a peculiarly sharp- sighted officer of 
 artillery, has often tested this point, and although there was 
 but one arrow to watch, and it was blown in the open air, he 
 could not see it until it either struck or passed him (of course 
 the poisoned end was cut off). What, then, would be the 
 result of a number of these deadly missiles hurled out of a 
 dense bush may easily be imagined. 
 
 An account of the poison with which these arrows are armed 
 will be iound on p. 64. 
 
 THE reader will please to remember that in all these cases 
 the missile is propelled by air which is compressed by the aid of 
 the lungs, and forced into the tube behind the bullet or arrow. 
 Now, the AIR-GUN, which really can be made a formidable 
 weapon, is constructed on exactly the same principle as the pea- 
 shooter and the blow-guns, except that the air is compressed by 
 the human arm instead of the human lungs. There are various 
 modifications of this weapon, but in all of them air is driven 
 into a strong chamber by means of a forcing syringe, and is 
 released by the pull of the trigger, so as to drive out the missile 
 which has been placed in the barrel. 
 
 It is worthy of notice that the term "noiselessly destructive" 
 weapon, as applied to the air-gun, is entirely false. I have 
 already mentioned that with the blow-gun of tropical America 
 a definite explosion accompanies the flight of each arrow. The 
 same result occurs with the air-gun, the loudness of the report 
 being in exact proportion to the force of the air, each succes- 
 sive report becoming slighter and the propulsive power weaker 
 until a new supply of air is forced into the chamber. 
 
 HOWEVER dissimilar in appearance may be the cannon, rifle, 
 pistol, or any other firearm, to the pea- shooter and its kin, the 
 principle is exactly the same in all. It has been already men- 
 tioned that in the blow-guns the air is compressed by the 
 exertion of human lungs, and in the air-gun the compression 
 is achieved by human hands. 
 
 But with the firearm a vast volume of expansible gas is 
 kept locked up in the form of gunpowder, gun-cotton, ful-
 
 78 NATURE'S TEACHINGS. 
 
 minating silver, or other explosive compound, and is let loose, 
 when wanted, by the aid of fire. 
 
 IN the illustration are represented on the right hand the 
 blow- guns of America and Borneo, and below them is the 
 cannon as at present made. On the left hand of the same 
 
 CH<ETODON, OE ABCHEB-FISH. BLOW-GUNS CANNON. 
 
 illustration is seen a representation of a natural gun which has 
 existed for thousands of years before gunpowder was invented, 
 and very long before the savage of Borneo or America dis- 
 covered the blow-gun. 
 
 It is the ARCHER-FISH (Chcetodon), which possesses the curious 
 power of feeding itself by shooting drops of water at flies, and 
 very seldom failing to secure its prey. 
 
 There are several species of this very curious fish spread 
 over the warmer parts of the world, and their remarkable mode 
 of obtaining prey is very well known in all. There is, indeed, 
 scarcely any phenomenon in Nature more remarkable than the 
 fact of a fish being able to shoot a fly with a drop of water 
 projected through its tubular beak, if we may use that expres- 
 sion for so curiously modified a mouth. 
 
 Indeed, so certain is the fish of its aim, that in Japan it is 
 kept as a pet in glass vases, just as we keep gold fish in 
 England, and is fed by holding flies or other insects to it 
 on the end of a rod a few inches above the surface of the 
 water. The fish is sure to see the insect, and equally sure 
 to bring it down with a drop of water propelled through its 
 beak. 
 
 It is worthy of remark that the same principle was once, 
 though unsuccessfully, employed in the propulsion of carriages, 
 under the name of the Pneumatic Railway. Some of my 
 readers may remember the railway itself, or at all events the 
 disused tubes which lay for so many years along the Croydon
 
 THE THROWING-STICK. 79 
 
 Railway. Speed was obtained, as I can testify from personal 
 experience, but the expense of air-pumps and air-tight tubing 
 was too great to be covered by the income, especially as the rats 
 ate the oiled leather which covered the valves. 
 
 I FIND some little difficulty in arranging 'the subject which, 
 comes next in order. It might very properly be ranked among 
 the Levers, which will be treated of in another chapter ; or it 
 might be placed among the examples of centrifugal force, 
 together with the sling, the " governor " of the steam-engine, 
 &c., all of which will be more fully described in their places. 
 However, as we are on the subject of Projectiles, we may as 
 well take it in the present place. 
 
 It is the THROWING-STICK, by which the power of the human 
 arm is enormously increased, when a spear is to be hurled. 
 Perhaps the most expert spear-throwers in the world are to be 
 found among the Kafir tribes of Southern Africa, and yet the 
 most experienced among them could not make sure of hitting 
 a man at any distance above thirty or forty yards. But the 
 throwing-stick gives nearly double the range, and I have seen 
 the comparatively slight and feeble Australian hurl a spear 
 to a distance of a hundred yards, and with an aim as perfect 
 as that of a Kafir at one-fourth of the distance. 
 
 The mode in which this feat is performed is shown in the 
 accompanying diagram. Instead of holding the spear itself, 
 the native furnishes himself with a " Throwing-stick." This 
 weapon varies greatly in shape and size, but a very good idea of 
 its form, and the manner of using it, may be obtained from 
 the accompanying illustration, which was drawn from the 
 actual specimen as held by an Australian native. 
 
 The throwing-stick is armed at the tip with a short spike, 
 which fits into a little hole in the but of the spear. The stick 
 and spear being then held as shown in the illustration, it is 
 evident that a powerful leverage is obtained, varying according 
 to the length of the stick. I possess several of these instru- 
 ments, no two of which are alike. 
 
 It is rather remarkable that among the Esquimaux a throw- 
 ing-stick is also used, exactly similar in principle, but differing 
 slightly in structure, the but of the spear fitting into a hole 
 at the end of the throwing-stick. Wood being scarce among
 
 80 NATURE'S TEACHINGS. 
 
 the Esquimaux, these instruments are mostly made of bone. 
 I possess one, however, which is made of wood, beautifully 
 polished, and adorned with a large blue stone, something like 
 a turquoise, set almost in its middle. One of the most curious 
 points in the formation of the Esquimaux weapon is, that the 
 
 JAW OP 8NAK.E. THROWISG-STICK. 
 
 but is grooved and channelled so as to admit the fingers and 
 thumb of the right hand. The average length of this instru- 
 ment is twenty inches. 
 
 IN New Caledonia the natives use a contrivance for increas- 
 ing the power of the spear, which is based on exactly identical 
 principles, though the mode of carrying them out is different. 
 A thong or cord of some eighteen inches in length is kept in 
 the right hand, one end being looped over the forefinger, and 
 the other, which is terminated by a button, being twisted round 
 the shaft of the spear. When the weapon is thrown, the 
 additional leverage gives it great power ; and it is a note- 
 worthy fact that the sling- spear of New Caledonia has enabled 
 us to understand the otherwise unintelligible " amentum " of 
 the ancient classic writers. 
 
 PASSING from Art to Nature, we have in the jaw of the 
 serpent an exact type of the peculiar leverage by which the 
 spear is thrown. If the reader will refer to the illustration, 
 he will see that the lower jaw of the snake, instead of being 
 set directly on the upper jaw, is attached to an elongated bone, 
 which gives the additional leverage which is needful in the 
 act of swallowing prey, after the manner of serpents. 
 
 IN War and in Peace we have been long accustomed to 
 shield the edges and points of our sharp weapons with sheaths, 
 and even the very savages have been driven to this device.
 
 SHEATHED WEAPONS. 
 
 81 
 
 I have in my collection a number of sheathed weapons from 
 nearly all parts of the world, and it is a remarkable fact that the 
 Fan tribe, who are themselves absolutely naked, sheathe their 
 daggers and axes as carefully as we sheathe our swords and 
 bayonets. In some points, indeed, they go beyond us ; for the 
 most ignorant Fan savage would never think of blunting the 
 edge of his weapon by sheathing it in a metal scabbard. Their 
 sheaths are beautifully made of two flat pieces of wood, just 
 sufficiently hollowed to allow the blade to lie between them, 
 and bound together with various substances. For example, 
 the sheaths of one or two daggers in my possession are made 
 of wood covered with snake-skin, while others are simply 
 wood bound with a sort of rattan. Even the curious missile- 
 axe which the Fan warrior uses with such power is covered 
 with a sheath when not in actual use. 
 
 The figure on the right hand of the illustration represents 
 the heads of two speara of Waganda warriors. "When they 
 
 APPARATUS AND BHEATH8. 
 
 FLEA. BOMBYL1CS. 
 
 SHEATHED SPEAKS OF WAGAXDA. 
 
 present themselves before their king, the warriors must not 
 appear without their weapons, and it would be contrary to all 
 etiquette to show a bare blade except in action. The sheath 
 can be slipped off in a moment, but there it is, and any man 
 who dared to appear before his sovereign without his weapon, 
 or with an unsheathed spear, would lose his life on the spot, 
 so exact is the code of etiquette among these savages. 
 
 The sheathed spears of Nature are shown in the same illus- 
 tration. On the left is a side view of the piercing apparatus of 
 the common Gnat.
 
 82 
 
 NATURE S TEACHINGS. 
 
 In the middle is the compound piercing apparatus of the 
 common Flea, with which we are sometimes too well acquainted, 
 the upper figure showing the lancets and sheaths together, and 
 the lower exhibiting them when separated. 
 
 On the right is shown the group of mouth-lancets belonging 
 to one of the Humble-bee flies (Bombylius}. These flies do 
 not suck blood like the Mosquito, the Flea, and the Gad-fly, 
 but they use the long proboscis for sucking the sweet juices 
 out of flowers, and in consequence it is nearly of the same 
 form as if it were meant for sucking blood. Indeed, there are 
 some insects which do not seem to care very much whether 
 the juice which they suck is animal or vegetable. 
 
 On the right hand of the illustration is seen an Indian 
 sword, or " Tulwar," drawn from one of my own specimens. 
 I have selected this example on account of the structure of the 
 sheath. It is evident, from the form of the blade, that the 
 sword cannot be sheathed point foremost, and that therefore 
 
 6 CLAW. SHEATH OPENING ALONG 
 THE CUBVED BACK. 
 
 INDIAN TULWAR. SHEATH OPENING 
 ALONG THE CUBVED BACK. 
 
 some other plan must be used. In this weapon the sheath is 
 left open on one side, the two portions being held together 
 by the straps which are shown in the figure. Of course there 
 is loss of time in sheathing and drawing such a sword, but the 
 peculiar shape of the blade entails a necessity for a special 
 scabbard. 
 
 On the other side is shown one of the fore-claws of a cat, 
 which, as we all know, can be drawn back into its simple
 
 LANCETS AND THEIR SHEATHS. 
 
 83 
 
 sheath between the toes, when it is not in use. This sheath 
 is exactly the same in principle as that of the Indian tulwar, 
 and any one can examine it by looking at the foot of a good- 
 tempered cat. I have done so even with a chetah, which is 
 not a subject that would generally be chosen for such a 
 purpose. 
 
 On the next illustration is shown an ordinary Lancet, in 
 which the blade is guarded between a double sheath, the two 
 halves and the blade itself working upon a common pivot. 
 As for the ordinary sword and dagger sheaths, it is not worth 
 while to figure them. 
 
 TURNING to the opposite side of the illustration, we shall see 
 a few of the innumerable examples in which the principle of 
 the sheath was carried out in Nature long before man came on 
 the earth. 
 
 The reader should compare this figure with the side view of 
 the Gnat's lancets given on p. 81. 
 
 They represent the cutting and piercing instruments of 
 several insects, all of which are very complicated, and are 
 
 SURGEON'S LANCET 
 PAKTLY OPEN. 
 
 LANCETS OP TABANUS 
 CLOSED. 
 
 LANCETS OF MOSQUITO 
 PABTLY OPEN. 
 
 sheathed after the manner of the lancet. Indeed, they are 
 popularly known as "mouth-lancets," and with reason, as 
 the reader may see by reference to the illustration.
 
 84 NATURE'S TEACHINGS. 
 
 On the extreme left are shown the head and closed lancets of 
 a foreign Gad-fly, the lancets being all in their sheaths, and 
 showing the character of the weapon which enables a small fly 
 to be master, or rather mistress, of the forest. I say mistress, 
 because in all these cases it is the female alone that possesses 
 these instruments of torture. 
 
 Next it is a magnified representation of the lancets of the 
 common Mosquito, as seen from above, both lancets being 
 removed from their sheaths and separated.
 
 WAR AND HUNTING. 
 
 CHAPTER IV. 
 
 The Net, as used in Hunting and War. The Seine-net, as used for Fishing. 
 Also as a means of Hunting. Net for Elephant-catching. Steel Net for 
 Military Purposes. Web of the Garden Spider. The Casting-net, as used 
 in Fishing. Also as employed (in the Combats of the ancient Circus. 
 Various Kinds of Casting-nets. The Argus Star-fish and the Barnacle. 
 The Rod and Line. Angling of various Kinds. The Polynesian as an 
 Angler. The Angler-fish. " Playing " a Fish. The Nemertes and its Mode 
 of Feeding. Mr. Kingsley's Account of it. Power of Elongation and Con- 
 traction. The Cydippe. Spring-traps. The Gin, Rat-trap, and Man-trap. 
 Jaws of Dolphin, Porpoise, and Alligator. Legs of Phasma. Baited 
 Traps. Carnivorous Plants and their Mode of Feeding. Birdlime. " Peg- 
 ging" for Chaffinches. Curious Mode of Tiger-killing. Ant-eater and ita 
 Mode of Feeding. The Drosera. Web of Spider and its Structure. 
 
 THE NET. 
 
 A LTHOUGH the Net is but seldom employed for the pur- 
 * poses of general warfare, it was once largely used in 
 individual combats, of which we will presently treat. In 
 hunting, however, especially in fishing, the Net has been in 
 constant use, and is equally valued by savages and the most 
 civilised nations. 
 
 To begin with the fisheries. Even among ourselves there 
 are so many varieties of fishing-nets that even to enumerate 
 them would be a work of time. However, they are all based 
 on one of two principles, i.e. the nets which are set and the 
 nets which are thrown. 
 
 We will begin with the first. 
 
 ON the right hand of the illustration, and at the bottom, 
 may be seen a common Seine-net being "shot" in the sea. 
 This form of net is very long in proportion to its width, some 
 of these nets being several miles long. The upper edge
 
 86 
 
 NATURES TEACHINGS. 
 
 of the net is furnished with a series of cork bungs, which 
 maintain it on the surface, while the lower edge has a corre- 
 sponding set of weights, which keep the net extended like a 
 wall of meshes. Any fish which come against this wall are, of 
 course, arrested, and are generally caught by the gill-covers in 
 their vain attempts to force themselves through the meshes. 
 
 We may see representations of fishing with the seine-net in 
 the sculptures and paintings of Egypt and Assyria; and in 
 the Berlin Museum there is a part of an Egyptian seine-net 
 with the leads still upon the lower edge, and the upper edge 
 bearing a number of large pieces of wood, which acted as 
 buoys, and served the same purpose as our corks. 
 
 IN hunting, this plan has been adopted for many centuries, 
 the upper edge of the net being supported on poles, and the 
 lower fastened to the ground in such a manner as to leave the 
 net hanging in loose folds. While this part of the business 
 
 SPIDEB-WEB. 
 
 HUXTIXii-XJST. 
 
 THE SEINE-NET. 
 
 is being completed by the servants, the hunters are forming 
 a large semicircle, in which they enclose a number of wild 
 beasts, which they drive into the nets or " toils" by gradually 
 contracting the semicircle. The ancient sculptures give us 
 accounts of nets used in exactly this manner. There are 
 represented the nets rolled up ready for use, and being carried 
 on the shoulders of several attendants, who are bearing them 
 to the field. Then there are the nets set up on their poles, 
 and having enclosed within them a number of wild animals, 
 such as boars and deer. 
 
 In various parts of India, hunting with the net is one of the
 
 HUNTING-NETS. 87 
 
 chief amusements of their principal men, and the variety of 
 game driven into the toils is really surprising, and affords a 
 magnificent sight to those who view it for the first time. 
 Even the tiger himself cannot leap over the nets because they 
 are so high, nor force his way through them, because their folds 
 hang so lightly that they offer no resistance to his efforts. 
 
 A very simple net on similar principles is used for catching 
 elephants. It is formed of the long creeping plants that 
 fling themselves in tangled masses from tree to tree. These 
 creepers are carefully twisted into a net-like form, without 
 being removed from the trees, and when a sufficient space has 
 been enclosed the elephants are driven into it. Not even their 
 gigantic strength and tons of weight are capable of breaking 
 through a barrier which, apparently slight, is as strong as if it 
 were built of the tree-trunks on which the creepers are hung. 
 
 This net is seldom used for military purposes, though I 
 have seen one, which I believe still exists, and would do gooo! 
 service. In one of our largest fortresses there is a subterra- 
 nean corridor, through which it is desirous that the enemy 
 should not penetrate. One mode of defence consists of a large 
 net made of steel hanging loosely across it. The meshes are 
 about ten inches square, so that the defenders can fire frpm 
 their loopholes through the meshes, while the assailants, even 
 if they knew of its position, would find that nothing smaller 
 than a field-gun would have any effect on this formidable net. 
 
 THE natural analogy of the fixed net is evidently the web of 
 the common Garden Spider, or Cross Spider (Epeira diademd), 
 whose beautiful nets we all must have admired, especially when 
 we are wise enough to get up sufficiently early in the morning 
 to see the webs with the dewdrops glittering on them. 
 
 Last year there was a wonderful sight. Within a mile of 
 my house there is a long iron fence, which in one night had 
 been covered with the webs of the garden spider. The fol- 
 lowing morning, though bright, was chilly, so that the dew- 
 drops were untouched. I happened to pass by the fence soon 
 after sunrise, and was greatly struck with the astonishing 
 effects which could be produced with such simple materials as 
 water and web. The dewdrops were set at regular intervals 
 upon the web, so as to produce a definite and beautiful pattern,
 
 88 NATURE'S TEACHINGS. 
 
 the whole line of fence looking as if it had been woven in 
 fine lace. 
 
 Then, as the fence runs north and south, and the path is on 
 the westward of it, every passenger saw the rays of the rising 
 sun dart through these tiny globules, and convert every one of 
 them into a jewel of ever-changing colours. It seemed a pity 
 that such beauty could but last for an hour or so, or that these 
 exquisite webs should only be used for catching flies. 
 
 NEXT comes the Casting-net in its various forms. This net is 
 mostly circular, and is loaded round the edge with small leaden 
 plummets. It is evident that, if such a net could be laid quite 
 flat upon the water, it would assume a dome-like shape, in con- 
 sequence of the circumference being heavier than the centre, 
 and would sink to the bottom, enclosing anything which came 
 within its scope. 
 
 The difficulty is to place the net in such a manner, and this 
 is accomplished by throwing it in a very peculiar way. The 
 net is gathered in folds upon the shoulder, which it partially 
 envelops. By a sudden jerk the thrower causes it to fly open 
 with a sort of spinning movement, and when well cast it will 
 fall on the water perfectly flat. 
 
 After allowing it to sink to the bottom, the fisherman draws 
 it very gently by a cord attached to its middle. As he raises 
 it the weights of the leaded circumference are drawn nearer 
 and nearer together by their own weight, and finally form it 
 into a bag, within which are all the living creatures which it 
 has enclosed. 
 
 Though the Casting-net has never been used in warfare, it 
 was one of the favourite implements in gladiatorial combats 
 among the Romans. Two men were opposed to each other ; 
 one, called the Retiarius or Netsman, being quite naked, except 
 sometimes a slight covering round the waist, and armed with 
 nothing but a Casting-net and a slight trident, which could not 
 inflict a deadly wound. The other, called the Secutor or 
 Follower, from his mode of fighting, was armed with a visored 
 helmet, a broad metal belt, and armour for the legs and arms. 
 He also carried a shield large enough to protect the upper 
 part of the body, and a sword. It will be seen, therefore, 
 how great was the power of the Casting-net, when it enabled
 
 THE CASTING- NET. 89 
 
 its naked bearer to face such odds of offensive and defensive 
 armour. 
 
 When the two met in combat, the Retiarius tried to fling his 
 net over his adversary, and if he succeeded, the fate of the 
 latter was sealed. Entangled in the loose meshes, he could 
 scarcely move his limbs, while the sharp prongs of the long- 
 shafted trident came darting in at every exposed point, and 
 exhausting the man with pain and loss of blood. The trident 
 
 w 
 
 ABGtrs STAB FISH. "FAN" OP BARNACLE. BETIABIUS. 
 
 was in itself so feeble a weapon, that if the Secutor were 
 vanquished and condemned to death by the spectators, his 
 antagonist could not kill him, but had to call another Secutor 
 to act as executioner with his sword. 
 
 Should he fail in his cast, the Retiarius drew back his net 
 by the central cord, and took to flight, followed by the Secutor, 
 who tried to wound him before he could re-fold his net upon 
 his shoulder, ready for another cast. It is worthy of notice 
 that in these singular combats the netsman seems generally to 
 have been the victor. A Retiarius with his net is shown in the 
 illustration. 
 
 I may mention that our ordinary bird-catchers' nets, and 
 even the entomologist's insect-net, are only modifications of 
 the Casting-net. 
 
 Now for Nature's Casting-nets, two examples of which are 
 figured, though there are many more. These two have been 
 selected because they are familiar to all naturalists. 
 
 The first is the Argus Star-fish, Basket-urchin, or Sea-basket.
 
 90 NATURE'S TEACHINGS. 
 
 The innumerable rays and their subdivisions, amounting to 
 some eighty thousand in number, act as the meshes of the 
 net. All the rays are flexible and under control. "When the 
 creature wishes to catch any animal for prey, it throws its 
 tentacles over it, just like the meshes of a net. It then draws 
 the tips of the rays together, just as is done by the circum- 
 ference of the casting-net, and so encloses its prey effectually. 
 
 THE next specimen is the net-like apparatus of the common 
 Acorn Barnacles, with which our marine rocks are nearly 
 covered. These curious beings belong to the Crustacea, and the 
 apparatus which is figured on page 89, and popularly called the 
 " fan," is, in fact, a combination of the legs and their appendages 
 of bristles, &c. When the creature is living and covered with 
 water, the fan is thrust out of the top of the shell, expanded 
 as far as possible, swept through the water, closed, and then 
 drawn back again. With these natural casting-nets the Bar- 
 nacles feed themselves, for, being fixed to the rock, they could 
 not in any other way supply themselves with food. There are 
 many similar examples in Nature, but these will suffice. 
 
 THE ROD AND LINE. 
 
 THAT both terrestrial and aquatic nets should have their 
 parallels in Nature is clear enough to all who have ever seen a 
 spider's web, or watched the " fan" of the barnacle. But that 
 the rod and baited line, as well as the net, should have existed 
 in Nature long before man came on earth, is not so well known. 
 Yet, as we shall presently see, not only is the bait represented 
 in Nature, but even our inventions for " playing " a powerful 
 fish are actually surpassed, 
 
 We will begin with the Bait. 
 
 In nearly all traps a bait of some kind is required, in order to 
 attract the prey, and when we come from land to attract the 
 dwellers in water to our hooks, it is needful that bait of some 
 kind should be used, were it only to deceive the eye, though 
 not the nostrils or palate, of the fish. 
 
 A notable example of the deception is given in the common 
 artificial baits of the present day, which are made to imitate 
 almost any British insect which a fish might be disposed to eat.
 
 BAITED HOOKS. 91 
 
 Perhaps the best instance of this deception is that which is. 
 practised by sundry Polynesian tribes. They have seen that the 
 Coryphene or Dorado, and other similar fish, are in the habit of 
 preying upon the flying-fish, and springing at them when they 
 are tolerably high in the air. So these ingenious semi-savages 
 dress up a hook made of bone, ormer-shell, and other materials, 
 making the body of it into a rudely designed form of a fish. 
 A hole is bored transversely through it at the shoulders, and a 
 bunch of stiff fibres is inserted to represent the wings. Another 
 bunch does duty for the tail. 
 
 The imitation bait being thus complete, it is hung to a long 
 and slender bamboo rod, which projects well beyond the stern 
 of a canoe, and is so arranged that the hook is about two feet or 
 so from the surface. The Coryphene, seeing this object skim- 
 ming along, takes it for a flying-fish, leaps at it, and is caught 
 by the hook. There are in several collections specimens of these 
 ingenious hooks, and I possess one which is made on similar 
 principles, but intended for use in the water, and not in the air. 
 It is, in fact, a " spoon-bait." 
 
 One point of ingenuity must be mentioned, as it really belongs 
 to the principle of the bait. These same savages, having 
 noticed that large sea-birds are in the habit of hovering over 
 the flying-fish, and would probably be seen by the Coryphenes, 
 rig up a very long bamboo rod, tie to its end a large bundle 
 of leaves and fibres, and then fix it in the stern of the boat, the 
 sham bird being hung some twenty feet above the sham fish. 
 There is a refinement of deception here, for which we should 
 scarcely give such savages their due credit. 
 
 IN Art, then, we bait our hooks either with real or false food, 
 and so attract the fish. 
 
 In Nature we have a most accomplished master of the art of 
 baiting, who has the wonderful power of never needing a 
 renewal of his bait. A glance at the left-hand figure of the 
 next illustration will show that I allude to the Angler-fish, 
 sometimes called the Fishing-frog (Lophius piscatorius}. This 
 remarkable creature has a most enormous mouth, and compara- 
 tively small body. On the top of its head are some curious 
 bones, set just like a ring and staple, so as to move freely in 
 every direction. A figure of this piece of mechanism will be
 
 92 NATURE'S TEACHINGS. 
 
 given in a future page. At the end of these bones are little 
 fleshy appendages, which must be very tempting to most fish, 
 which are always looking out for something to eat. As they are 
 being waved about, they look as if they were alive. The fish 
 darts at the supposed morsel, and is at once engulfed in the 
 huge jaws of the Angler-fish, which, but for this remarkable 
 apparatus, would be scarcely able to support existence, as it is 
 
 ANGLER-FISH. 
 
 but a sluggish swimmer, and yet needs a large supply of food. 
 The illustration, representing on the right hand a fish attracted 
 to a bait, and on the left, the Angler-fish, with its bait-like 
 appendage to the head, speaks for itself. 
 
 PASSING to the art of Angling with a rod and line, we now 
 arrive at another development. 
 
 Supposing a fish to have taken the bait, and to have been 
 firmly hooked, how is it to be landed ? The simplest plan is, 
 of course, to have a very thick and strong line which will not 
 break with the weight of any ordinary fish. 
 
 This is very well in sea-fishing, where a line made of whip- 
 cord will answer the purpose in most cases. But, in river 
 fishing, we have the fact that the fish are so shy that a linen 
 thread would scare them, and so strong and active, that even 
 whip-cord would not prevent them from breaking the line, or 
 tearing the hook out of their mouths. So the modern angler 
 sets himself to the task of combating both these conditions. 
 In the first place, he makes the last yard or two of his line of 
 " silkworm-gut " a curious substance made from the silk- 
 vessels of silkworms, and nearly invisible in the water. In the 
 next place, he has a very elastic rod ; and, in the third, he has 
 forty or more yards of line, though perhaps only twenty feet are 
 in actual use until the fish is hooked. The remainder of the 
 line is wound upon a winch fixed to the handle of the rod.
 
 " PLAYING " A FISH. 
 
 93 
 
 Thus, when a powerful fish is hooked and tries to escape, the 
 line is gradually let loose, so as to yield to its efforts. When it 
 becomes tired by the gradual strain, the line is again wound in, 
 and in this way a fish which would at the first effort smash 
 rod and line of a novice will, in the hands of an experienced 
 fisherman, be landed as surely as if it were no bigger than a 
 gudgeon. 
 
 NATURE has in this case also anticipated Art, and surpassed 
 all her powers. 
 
 There is a wonderful worm, common on our southern coasts, 
 and bearing, as far as I know, no popular name. It is known to 
 
 NKMEBTE8. "PLAYlSQ" A PlSH. 
 
 the scientific world as Nemertes Borlasii. It possesses the power 
 of extension and contraction more than any known creature, 
 and uses those powers for the purpose of capturing prey. The 
 fishermen say that this worm can extend itself to a length of 
 ninety feet, and as Mr. Davis found one to measure twenty-two 
 feet, after being immersed in spirits of wine, it is likely that 
 their account may be true, especially as the spirit greatly con- 
 tracted the animal in point of length. 
 
 A most vivid description of this worm is given by C. Kingsley, 
 in his " Glaucus," and was written before he knew its name. 
 
 "Whether we were intruding or not, in turning this stone, 
 we must pay a fine for having done so ; for there lies an animal 
 as foul and monstrous to the eye as ' hydra, gorgon, or chimacra
 
 94 NATURE'S TEACHINGS. 
 
 dire,' and yet so wondrously fitted to its work that we must 
 needs endure for our own instruction to handle and to look at 
 it. Its name I know not (though it lurks here under every 
 stone), and should be glad to know. It seems some very ' low ' 
 Ascarid or Planarian worm. 
 
 " You see it ? That black, shiny, knotted lump among the 
 gravel, small enough to be taken up in a dessert spoon. Look 
 now, as it is raised and its coils drawn out. Three feet, six, 
 nine at least ; with a capability of seemingly endless expan- 
 sion ; a slimy tape of living caoutchouc, some eighth of an inch 
 in diameter, a dark chocolate black, with paler longitudinal 
 lines. 
 
 " Is it alive ? It hangs helpless and motionless, a mere 
 velvet string, across the hand. Ask the neighbouring Annelids 
 and the fry of the rock-fishes, or put it into a vase at home, 
 and see. It lies motionless, trailing itself among the gravel ; 
 you cannot tell where it begins or ends ; it may be a dead strip 
 of seaweed, Himanthalia lorea, perhaps, or Chorda filum, or even 
 a tarred string. 
 
 " So thinks the little fish who plays over and over it, till he 
 touches at last what is too surely a head. In an instant a bell- 
 shaped sucker mouth has fastened to his side. In another 
 instant, from one lip, a concave double proboscis, just like a 
 tapir's (another instance of the repetition of forms), has clasped 
 him like a finger ; and now begins the struggle : but in vain. 
 He is being ' played ' with such a fishing-line as the skill of 
 a Wilson or a Stoddart never could invent ; a living line, with 
 elasticity beyond that of the most delicate fly-rod, which 
 follows every lunge, shortening and lengthening, slipping and 
 twining round every piece of gravel and stem of seaweed, with 
 a tiring drag such as no Highland wrist or step could ever 
 bring to bear on salmon or on trout. 
 
 " The victim is tired now ; and slowly, and yet dexterously, 
 his blind assailant is feeling and shifting along his side, till he 
 reaches one end of him ; and then the black lips expand, and 
 slowly and surely the curved finger begins packing him end 
 foremost down into the gullet, where he sinks, inch by inch, 
 till the swelling which marks his place is lost among the coils, 
 and he is probably macerated to a pulp long before he has 
 reached the opposite extremity of his cave of doom.
 
 THE SPRING-TRAP. 95 
 
 " Once safe down, the black murderer slowly contracts again 
 into a knotted heap, and lies, like a boa with a stag inside him, 
 motionless and blest." 
 
 The accuracy as well as the pictorial effect of this description 
 cannot be surpassed. The " velvety " feel of the creature is 
 most wonderful, as it slips and slides over and among the 
 fingers, and makes the task of gathering it together appear quite 
 hopeless. 
 
 This astonishing worm is drawn on the left hand of the 
 illustration on page 93, so as to show the way in which the 
 body is contracted or relaxed at will. On the other side of the 
 illustration is an angler, armed with all the paraphernalia of 
 his craft, and doing imperfectly that which the Nemertes does 
 with absolute perfection. 
 
 A similar property belongs to the long, trailing tentacles of 
 the Cydippe, which is described and figured on page 16. When 
 they come in contact with suitable prey, all struggle is useless, 
 the tentacles contracting or elongating to suit the circum- 
 stances, and at last lodging the prey within the body of the 
 Cydippe. 
 
 THE SPRING-TRAP. 
 
 WE are all familiar with the common Spring-trap, or Gin, as 
 it is sometimes called. 
 
 It varies much in form and size, sometimes being square and 
 sometimes round ; sometimes small enough to be used as a rat- 
 trap, and sometimes large enough to catch and hold human 
 beings, in which case it was known by the name of man-trap. 
 This latter form is now as illegal as the spring-gun, and though 
 the advertisement " Man-traps and Spring-guns are set in these 
 grounds " is still to be seen, neither one nor the other can be 
 there. 
 
 They are all constructed on the same principle, namely, a 
 couple of toothed jaws which are driven together by a spring, 
 when the spring is not controlled by a catch. They are 
 evidently borrowed from actual jaws, the same words being used 
 to signify the movable portions and notches of the trap as are 
 employed to designate the corresponding parts in the real jaw. 
 
 In both figures of the accompanying illustration we shall 
 see how exact is the parallel. On the right hand is a
 
 96 
 
 NATURE S TEACHINGS. 
 
 common rat-trap, or gin, such as is sold for eightpence, with 
 the jaws wide open, so as to show the teeth. On the left is a 
 
 JAWS OF DOLPHIN (OPEN). 
 
 BAT-TBAP (OPEN). 
 
 sketch of the upper and lower jaws of the Dolphin, in which 
 an exactly analogous structure is to be seen. 
 
 The figure on the right hand of the lower illustration shows 
 a man-trap as it appears when closed, the teeth interlocking so 
 as exactly to fit between each other. The same principle is 
 exhibited in the jaws of the Porpoise, which are seen on the left 
 of the illustration. The jaws of an Alligator or Crocodile would 
 have answered the purpose quite as well, inasmuch as their 
 
 JAWS OF PORPOISE (CLOSED). 
 
 MAN-TRAP (CLOSED). 
 
 teeth interlock in a similar fashion, but I thought that it would 
 be better to give as examples the jaws of allied animals. The 
 reason for this interlocking is evident. All these creatures feed 
 principally on fish, and this mode of constructing the jaws 
 enables them to secure their prey when once seized. 
 
 Another example of such teeth is to be found in the fore-legs 
 of various species of Phasma and Mantis, as may be seen by 
 
 FOBE-LEGS OF PHASMA. 
 
 MOUSE-TRAP. 
 
 reference to the illustration. The latter insects are wonderfully 
 fierce and pugnacious, fighting with each other on the least 
 provocation, and feeding mostly on other insects, which they
 
 BAITED TRAPS. 97 
 
 secure in their deeply-toothed fore-legs. They use these legs 
 with wonderful force and rapidity, and it is said that a pair 
 of these insects fighting remind the observer of a duel with 
 sabres. 
 
 THE BAITED TRAP. 
 
 OUR space being valuable, we are not able to give many 
 examples of Baited Traps, whether in Art or Nature. 
 
 The most familiar example of this trap is the common Mouse- 
 trap, the most ordinary form of which is shown at the right 
 hand of the illustration on page 96. In all the varieties of 
 these traps, whether for mice or rats, the prey is induced to 
 enter by means of some tempting food, and then is secured or 
 killed by the action of the trap. Sometimes these traps are 
 made of considerable size for catching large game, and in Africa 
 are employed in the capture of the leopard, in India for taking 
 both tigers and leopards, and in North America for killing 
 bears. 
 
 We have already noticed one instance of a bait in the Angler- 
 fish, described in page 92, but in this case the bait serves 
 only for attraction, and the trap, or mouth, is not acted upon by 
 the prey. 
 
 There are, however, many examples in the botanical world, 
 where the plant is directly acted upon by the creature which is 
 to be entrapped, such being known by the now familiar term 
 " Carnivorous Plants." Of these there is a great variety, but 
 under this head I only figure two of them. 
 
 CEPHALOTU8. 
 
 The plant on the right hand is the Venus Fly-trap (Dionea 
 muscipula), which is common in the Carolinas. The leaves of 
 this plant are singularly irritable, and when a fly or other insect 
 
 H
 
 98 NATURE'S TEACHINGS. 
 
 alights on the open leaf, it seems to touch a sort of spring, and 
 the two sides of the leaf suddenly collapse and hold the insect 
 in their grasp. The strange point about it is, that not only is 
 the insect caught, but is held until it is quite digested, the 
 process being almost exactly the same as if it had been placed in 
 the stomach of some insect-eating animal. 
 
 So carnivorous, indeed, is the Dionea, that plants have been 
 fed with chopped meat laid on the leaves, and have thriven 
 wonderfully. Experiments have been tried with other sub- 
 stances, but the Dionea would have nothing to do with them. 
 The natural irritability of the leaves caused them to contract, 
 but they soon opened and rejected the spurious food. 
 
 On the left is the Cephalotus. This plant, instead of 
 catching the insect by the folding of the leaf, secures it by 
 means of a sort of trap-door at the upper end. The insect is 
 attracted by the moisture in the cup, and, as soon as it enters, 
 the trap-door shuts upon it, and confines it until it is digested, 
 when the door opens in readiness to admit more prey. 
 
 BIRDLIME. 
 
 BY a natural transition we pass to those traps which secure 
 their prey by means of adhesive substances. 
 
 With us, the material called "birdlime" is usually em- 
 ployed. This is obtained from the bark of the holly, and is of 
 the most singular tenacity. An inexperienced person who 
 touches birdlime is sure to repent it. The horrid stuff clings 
 to the fingers, and the more attempts are made to clear them, the 
 more points of attachment are formed. The novice ought to 
 have dipped his hands in water before he touched the birdlime, 
 and then he might have manipulated it with impunity. 
 
 The most familiar mode of using the birdlime is by "pegging " 
 for chaffinches. 
 
 In the spring, when the male birds are all in anxious rivalry 
 to find mates, or, having found them, to defend them, the 
 " P e g ers " S ^ the field 8 armed with a pot of birdlime 
 and a stuffed chaffinch set on a peg of wood. At one end of this 
 peg is a sharp iron spike. They also have a " call-bird," 
 i.e. a chaffinch which has been trained to sing at a given 
 signal.
 
 BIRDLIME. 
 
 99 
 
 When the " peggers " hear a chaffinch which is worth taking, 
 they feel as sure of him as if he were in their cage. They take 
 the peg, and stick it into the nearest tree-trunk. Round the 
 decoy they place half-a-dozen twigs which have been smeared 
 with birdlime, and arrange them so that no bird flying at the 
 decoy can avoid touching one of them. 
 
 The next point is, to order the call-bird to sing. His song 
 is taken as a personal insult by the chaffinch, which is always 
 madly jealous at this time of year. Seeing the stuffed bird, 
 he takes it for a rival, dashes at it, and touches one of the 
 
 ANT-BEAB. DBOSEBA. SPIDKB'S WEB. PEGGING CHAFFINCHES. TIGEB AND LIMED LEAVES. 
 
 twigs. It is all over with him, for the more he struggles and 
 flutters, the tighter is he bound by the tenacious cords of the 
 birdlime, and is easily picked up by the " pegger." 
 
 EVEN the fierce and powerful tiger is taken with this simple, 
 but terrible means of destruction. It is always known by what 
 path a tiger will pass, and upon this path the native hunter 
 lays a number of leaves smeared with birdlime. The tiger 
 treads on one of them, and. cat-like, shakes his paw to rid him- 
 self of it. Finding that it will not come off, he rubs his paw 
 on his head, transferring the leaf and lime to his face. 
 
 By this time he is in the middle of the leaves, and '.vorks 
 himself into a paroxysm of rage and terror, finishing by 
 blinding himself with the leaves that he has rubbed upon his
 
 100 NATURE'S TEACHINGS. 
 
 head. The hunters allow him to exhaust his strength by hia 
 struggles, and then kill him, or, if possible, capture him alive. 
 
 Both these scenes are represented on the right hand of the 
 illustration. 
 
 On the left hand are several examples of natural birdlime, 
 if we may use the term. The upper represents the Ant-bear, 
 or Great Ant-eater. This animal feeds in a very curious manner. 
 It goes to an ant-hill, and tears it rpen with its powerful 
 claws. The ants, of course, rush about in wild confusion. 
 Now, the Ant-eater is provided with a long, cylindrical tongue, 
 which looks very like a huge earth-worm, and which is covered 
 with a tenacious slimy secretion. As the ants run to and fro, 
 they adhere to the tongue, and are swept into the mouth of 
 their destroyer. 
 
 Below the Ant-eater is the common Drosera, or Sundew, one 
 of our British carnivorous plants. It captures insects, just as 
 has been narrated of the Dionea. But, instead of the leaf 
 closing upon the insect, it arrests its prey by means of little 
 globules of viscous fluid, which exude from the tips of the hairs 
 with which the surface of the leaf is covered. As soon as the 
 insect touches the hairs, they close over it, bind it down, and 
 keep it there until it is digested. Several species of Drosera 
 are known in England, and are found in wet and marshy 
 places. 
 
 Another plant, the Green- winged Meadow Orchis (Orchis 
 morio], has been known to act the part of the Drosera. A fly 
 had contrived to push its head against the viscous fluid of the 
 stigmatic surface, and, not being able to extricate itself, was 
 found sticking there. 
 
 Next comes a portion of the web of the common Garden 
 Spider (Epeira diadema). We have already treated of this 
 web as a net, and we will now see how it comes within the 
 present category. 
 
 In the web of the spider there are at least two distinct kinds 
 of threads. Those which radiate from the centre to the cir- 
 cumference are strong and smooth, while those which unite them 
 are much slighter, and are covered with tiny globules set at 
 regular intervals. "When the web is newly spun, these globules 
 are found to be nearly as tenacious as birdlime, and it is by 
 these means that an insect which falls into the web is arrested,
 
 SPIDER-WEBS. 101 
 
 and cannot extricate itself until the spider can seize it. After 
 awhile the globules become dry, refuse to perform their office, 
 and then the spider has to construct another web. So numerous 
 are these globules that, according to Mr. BlackwalTs calculations, 
 an ordinary net contains between eighty and ninety thousand. 
 Below the figure of the web itself are shown the two kinds of 
 thread, the upper bearing the globules, and the lower repre- 
 senting one of the plain radiating threads.
 
 WAR AND HUNTING. 
 
 CHAPTER V. 
 
 Eeverted Spikes and their Modifications. The Wire Mouse-trap. George III. 
 and the Trap. Fate of a Royal Finger. The Crab and lyobster Pot. The 
 Eel-pot. Cocoon of the Emperor-moth and its Structure. " Catchpoll " of 
 the Middle Ages. Deer-trap of India. Jaws of Pike and Serpent. The 
 Grass-snake. Jaws of Shark and their Power. Spiked Defences. The 
 Park Fence, the Garden Wall, and the Chevaux-de-frise. The " Square " of 
 Infantry Manoeuvres. The Abattis, and its Structure and Power. Ran- 
 jows and Caltrops. Ancient Ranjows in Ireland. Hedgehog. Porcupine 
 Echidna. House-builder Caterpillar and its Home. Repagula of Ascala- 
 phus. Tearing Weapons. The " Wag-nuk " of India. Armed Gauntlet of 
 the Middle Ages. Shark-tooth Gauntlet of Samoa, and the Uses to which it 
 was put. A terrible Warrior. The Tiger's Claw. Sport and Earnest. 
 
 REVERTED SPIKES. 
 
 T AM not quite satisfied with this title, but it is the best that 
 *- I can find. By it I mean that mode of mechanism which, 
 by means of an array of sharp spikes, permits an animal to 
 enter a passage easily, and yet prevents it from emerging. 
 
 Whether or not this, principle be now employed in warfare I 
 cannot say, but it is at all events used extensively in a small 
 
 COCOOX OF EMPEROR-MOTH. 
 
 MOUSE-TRAP. 
 
 way of hunting, the best known of which is the wire Mouse- 
 trap, one of which is shown at Fig. C on the illustration. A
 
 WIRE MOUSE-TRAP. 103 
 
 glance at the figure will explain the trap, even to those who 
 have never seen it. It is composed entirely of wire, and has 
 several round holes just above its lower edge. Each of these 
 holes is the entrance to a conical tunnel made of wires with 
 sharpened ends. 
 
 The mouse, being attracted by a bait placed within the trap, 
 tries to get at it. The doomed animal soon finds its way to one 
 of the entrances, and with little difficulty pushes itself through 
 the tunnel. Entering, however, is one thing, and returning is 
 another. The wire yielded easily enough in one direction, but 
 for the mouse to force itself against the converging points is 
 an impossible task. 
 
 Readers of the last century literature may perhaps re- 
 member, in the pages of " Peter Pindar," a very clever and 
 sarcastic account of the astonishment created in the mind of 
 George III. by a mouse-trap seen accidentally in the house of 
 a widow living at Salt Hill. 
 
 " Eager did Solomon, so curious, clap 
 His rare round optics on the widow's trap, 
 That did the duty of a cat. 
 
 And, always fond of useful information, 
 
 Thus wisely spoke he with vociferation, 
 What's that ? what ? what ? Hae, has ? what's that P ' 
 
 To whom replied the mistress of the house, 
 
 * A trap, an't please you, sir, to catch a mouse.' 
 
 ' Mouse catch a mouse ! ' said Solomon with glee ; 
 
 Let's see, let's see 'tis comical let's see 
 
 Mouse ! mouse ! ' then pleased his eyes began to roll 
 ' Where, where doth he go in ?' he marvelling cried. 
 ' There,' pointing to the hole, the dame replied. 
 ' What ! here P ' cried Solomon, ' this hole ? this hole P* 
 Then in he pushed his finger 'midst the wire, 
 That with such pains that finger did inspire, 
 He wished it out again with all his soul." 
 
 For my part I think that the King was quite right. If he 
 did not know the philosophy of a mouse-trap he ought to have 
 asked, and to have been rewarded, as in that case, by catching 
 with a trap of his own baiting, six mice on six successive days. 
 
 At Fig. B on the same illustration is shown the simple 
 apparatus by which crabs and lobsters are caught. The reader 
 will see that the principle is exactly the same in both cases, the 
 only difference being in material, the mouse-trap being made 
 of wire, and the crab -pot of wicker. 
 
 At Fig. D is shown the common Eel-pot, or Eel-basket. In 
 order to suit the peculiar shape of an eel, this basket is much
 
 104 NATURE'S TEACHINGS. 
 
 longer in proportion to its diameter than either of the preceding 
 traps, but it is formed on the same plan. An eel can easily 
 pass into the basket through the conical tunnel, but it is next 
 to impossible that it should find its way out again. 
 
 So much for Art, and now for Nature. 
 
 On the left hand of the illustration, at Fig. A, is the cocoon 
 of the common Emperor-moth (Saturnia pavonia minor), the 
 cocoon having been stripped of its outer envelope, so as to allow 
 its structure to be better seen. 
 
 The reader will at once perceive that the entrance of the 
 cocoon is guarded by an arrangement exactly like that of the 
 above-mentioned traps, except that the cone is reversed, so as 
 to allow of exit and to debar entrance. Guarded by this 
 conical arrangement of stout bristly appendages, the pupa can 
 remain in quiet during the time of its transformation, for nothing 
 can force its way through such a defence, and yet the moth, 
 when fully developed, can push its way out with perfect ease. 
 
 So admirably is this cocoon formed, that even after the moth 
 has escaped, it is impossible to tell by mere sight whether or 
 not it is within, the elastic wires closing on it after its passage. 
 
 ANOTHER modification of the same principle now comes before 
 us. In the above-mentioned examples the arrangement of the 
 reverted spikes is more or less conical, and they lead into a 
 chamber. In the present instances, however, the mere reversion 
 of the points is all that is needed. 
 
 The upper figure on the right hand represents the " Catch- 
 poll " of the Middle Ages, an allusion to which has already 
 been made. The reverted spikes turn on hinges, and are kept 
 apart by springs. This beautifully formed head was attached 
 to a long shaft, and was used for the purpose of dragging horse- 
 men from the saddle. It was thrust at the neck of the rider, 
 generally from behind. If a successful thrust were made, the 
 spring-points gave way, sprang back again, and thus clasped 
 the neck with a hold that was fatal to the rider. 
 
 BELOW it is the Deer-trap which is used in many parts of India, 
 and to which allusion has already been made. The reader will 
 see at once that if a deer should get its foot through the con-
 
 JAWS OF PIKE. 
 
 105 
 
 verging spikes, its doom is sealed, especially as there is a heavy 
 log of wood attached to the trap by a rope. 
 
 ON the left hand of the illustration are two examples of the 
 same principle taken from Nature, one belonging to fresh and 
 the other to salt water. 
 
 The upper figure represents the jaws of a Pike, with their 
 terrible array of reverted teeth. The Pike, as every one knows, 
 
 PIKE-JAWS. SHABK-JAW8. 
 
 CATCHPOLL. 
 
 DEEB-TBAP. 
 
 feeds upon other fish, and eats them in a curious manner. It 
 darts at them furiously, and generally catches them in the 
 middle of the body. After holding them for a time, for the 
 purpose, as I imagine, of disabling them, it loosens its hold, 
 makes another snap, seizes the fish by the head, and swallows it. 
 
 The Pike is so voracious that it will attack and eat fish not 
 very much smaller than itself, for its digestion is so rapid that 
 the head and shoulders of a swallowed fish have been found to 
 be half digested, while the tail was sticking out of the Pike's 
 mouth. Unless, therefore, the teeth of the Pike were so formed 
 as to resist any retrograde movement on the part of the prey, the 
 fish would starve ; for, lank and lean as it is, the Pike is one of 
 the most voracious creatures in existence, never seeming able 
 to get enough to eat, and yet, as is often found in such cases, 
 capable of sustaining a lengthened fast. 
 
 How well adapted is this arrangement of teeth for prevent- 
 ing the escape of prey, any one can tell who, in his early days 
 of angling, caught a Pike, and, after killing it, tried to extract 
 the hook without previously propping the jaws open. If once
 
 106 NATURE'S TEACHINGS. 
 
 the hand be inserted between the jaws, to get it out again 
 is almost impossible without assistance, and often has the 
 spectacle been exhibited of a youthful angler returning discon- 
 solately home, with his right hand in the mouth of a Pike, and 
 supporting the weight of the fish with his left. 
 
 THE teeth of a serpent are set in a similar manner, as can be 
 seen by reference to the illustration on page 80. An admirable 
 example of the power of this arrangement may be seen in the 
 jaws of our common Grass or Ringed Snake (Coluber natrix). 
 The teeth are quite small, very short, and not thicker than fine 
 needle-points. Yet, when once the snake has seized one of the 
 hind-feet of a frog, all efforts to escape on the part of the latter 
 are useless. The lower jaw is pushed forward, and then re- 
 tracted, and at each movement the leg is drawn further into 
 the snake's mouth, until it reaches the junction. 
 
 The snake then waits quietly until the frog tries to free 
 itself by pushing with its other foot against the snake's mouth. 
 That foot is then seized, the leg gradually following its com- 
 panion, and in this way the whole frog is drawn into the 
 interior of the snake. I have seen many frogs thus eaten, but 
 never knew one to escape after it had been once seized by the 
 snake. As these reptiles are perfectly harmless, it is easy to 
 try the experiment by putting the finger into a snake's 
 mouth, when it will be found that the assistance of the other 
 hand will be needful in order to extricate it. 
 
 BELOW the head of the pike is a view of a Shark's jaws, as 
 seen from the front. 
 
 Here, again, we have a similar arrangement of teeth, row 
 after row of which lie with their points directed towards the 
 throat of the fish. As, however, the pike and the snake 
 swallow their prey whole, their teeth need be nothing but 
 points. But, as the Shark is obliged to mangle its prey, and 
 seldom swallows it whole, its teeth are formed on a different 
 principle, each tooth being flat, wide, sharply pointed, and 
 having a double edge, each of which cuts like a razor. So knife- 
 like are they, indeed, that when a whale is killed, the sharks 
 which surround it bite off huge mouthfuls of blubber, and, as 
 they swarm by hundreds, cause no small loss to the whalers.
 
 CHEVAUX-DE-FRISE. 107 
 
 Many a man has lost a leg by a shark, the fish having bitten 
 it completely through, bone and all, and there have been eases 
 where a shark has actually severed a man's body, going off with 
 one half, and leaving the other clinging la the rope by which 
 he was trying to haul himself on board. 
 
 SPIKED DEFENCES* 
 
 THIS mode of defence is, perhaps, one of the most primitive in 
 existence, and takes a wonderful variety of forms. The spiked 
 railings of our parks and gardens, the broken glass on walls, 
 and even the spike' collars for dogs, are all modifications of 
 this principle. 
 
 On the illustrations are several examples of spikes used for 
 military purposes. The first is known by the name of 
 " Chevaux-de-frise," and is extensively used in forming an ex- 
 temporised fence where no great strength is needed. The structure 
 is perfectly simple, consisting of a number of iron bars with 
 sharpened ends, and an iron tube some inches in diameter, which 
 is pierced with a double set of holes. "When not in use, the bars 
 and tube can be packed in a small compass, but when they are 
 wanted, the bars are thrust through the holes as shown in the 
 illustration, and the fence is completed in a few minutes. The 
 horizontal bars are linked together by chains, so as to prevent 
 them from being shifted, and a defence such as this is generally 
 used for surrounding parks of artillery and the like. 
 
 ALL who have the least acquaintance with military matters 
 must be familiar with the " Square," and its uses in the days of 
 old. I say in the days of old, because in the present day the 
 rapid development of guns and rifles has entirely destroyed the 
 old arrangement. So lately, for example, as the day of Water- 
 loo, troops might manoeuvre in safety when they were more 
 than two hundred yards from the enemy. Now, a regiment 
 that attempted to manoeuvre in open ground would be cut to 
 pieces by the rifles of the enemy at a thousand yards' distance. 
 
 In those days, however, the square was a tower of safety 
 when rightly formed. It was formed in several rows. The 
 outer line knelt, with the butts of their muskets on the ground, 
 and the bayonet pointing upwards at an angle of forty-five.
 
 108 
 
 NATURE S TEACHINGS. 
 
 The others directed their muskets towards the enemy in such 
 a manner that nothing was presented to him but the points of 
 bayonets and the muzzles of loaded muskets. In all proba- 
 bility the battle of Waterloo would have been lost but for the 
 use of the "square," against which the French cuirassiers 
 dashed themselves repeatedly, but in vain. 
 
 However admirable may be the organization of the square, 
 whether it be hollow, or whether it be solid, like the " rallying 
 square," the principle is the same as that of the chevaux-de- 
 frise. 
 
 IN the next illustration is shown the " Abattis," one of the 
 most important elements of extemporised fortifications, and as 
 simple as it is important. 
 
 In any wooded country an abattis can be made in a very 
 short time by practised hands. All that is required is to cut 
 down the requisite number of trees, strip off the leaves and 
 twigs, and then cut off the smaller branches with sloping 
 
 TBEE-CADD18. 
 
 CHEVAUX-DE-FRISE. 
 
 blows of the axe, so as to leave a tolerably sharp point on each. 
 The trees are then laid side by side, with the ends of the 
 branches towards the enemy, and, the trunks being chained 
 together, a wonderfully effective defence is constructed. 
 
 Not only is it almost impossible for the bravest and strongest 
 man to force his way through the branches, even if the abattis 
 were undefended, but the tree-trunks afford shelter for swarms 
 of riflemen, who can pick off their assailants by aiming between 
 the branches, themselves being almost unseen, and entirely 
 covered.
 
 ABATTIS AND RANJOWS. 109 
 
 In Southern Africa, during the late wars, the abattis was 
 found to afford the best defence against the Kafirs, and that 
 when the waggons and abattis were united so as to form a 
 fortress, not even the naked Kafir, with all his daring courage, 
 
 could force his way through them. Even artillery has but 
 little power against the abattis, which allows the shot to pass 
 between the branches, and is very little the worse for it. 
 Accordingly, it is in great use for defending roads, especially 
 those which are bounded by high banks, and makes a formid- 
 able obstacle in front of gates. 
 
 THE two figures on the left of the same illustration represent 
 two modes of carrying out the same principle, the one showing 
 it as used in European warfare, and the other as a weapon of 
 defence which has been employed from time immemorial, and 
 is now in full use in many parts of the world. 
 
 Both these weapons are intended either to obstruct the 
 approach of an enemy, or to cover the flight of a retreating 
 force. The most simple and most ancient is the Ranjow, which 
 is shown on the right hand of the illustration. The ranjow 
 is nothing but a wooden stick varying in length from eighteen 
 inches to nearly three feet, and sharply pointed at each end. 
 In Borneo, China, &c., the ranjows are almost invariably made 
 of bamboo, as that plant can be cut to a sharp point by a 
 single stroke of a knife. (See page 59.) 
 
 When they are to be used, each soldier carries about a dozen 
 or so of them, and sticks one end of them into the ground, 
 taking care to make the upper end lean towards the enemy. 
 Simple as are these weapons, they are extremely formidable, for 
 it is necessary to pull up every ranjow before the troops can 
 advance. Sometimes it has happened that a body of soldiers are
 
 110 NATURE'S TEACHINGS. 
 
 driven over their own ranjows, and then the slaughter is 
 terrible. 
 
 Some years ago a numher of sketches were taken on the spot 
 from scenes in the Chinese war. Among them was one that 
 was absolutely terrible in its grotesqueness. It represented a 
 piece of ground thickly planted with ranjows, over which the 
 Chinese who had fixed them had been driven. They were 
 simply hung with human bodies in all imaginable and unima- 
 ginable attitudes, some transfixed on a single ranjow, and 
 others hanging on three or four, the body and limbs being 
 alike pierced by them. 
 
 That ranjows were once used in Great Britain is evident from 
 a discovery made by Col. Lane Fox. He had been excavating 
 the soil around an old Irish fort, and deep beneath the bog he 
 found a vast quantity of ranjows still set as the ancient 
 warriors had left them. They were evidently used to defend 
 a passage leading to the fort, and all of them were carefully set 
 with their points outwards. Col. L. Fox was good enough to 
 present me with several of these ancient weapons, which are 
 now in my collection. 
 
 ON the left is seen a piece of ground strewed with Caltrops, 
 or Crow's-feet, as they are sometimes called. These very 
 unpleasant implements are made of iron, and have four sharp 
 points, all radiating from one centre, so that no matter how 
 they may be thrown, one point must be uppermost. They are 
 used chiefly for the purpose of impeding cavalry, but I should 
 think, judging from the specimens which I have seen, that 
 infantry would find them very awkward impediments. 
 
 As for natural ranjows, they are so numerous that only a 
 very few examples can be given. 
 
 The most perfect and most familiar example is, perhaps, the 
 common Hedgehog, which, when rolled up, displays an array 
 of sharp points so judiciously disposed, that it fears but very 
 few foes. The same may be said of the Australian Echidna, 
 or Porcupine Ant-eater, and the Porcupine itself. Whether the 
 radiating bristles of the larva of the Tiger-moth, commonly 
 called the Woolly Bear, come under the same category, I can- 
 not say, but think it very likely.
 
 TREE-CADDIS. Ill 
 
 Among vegetables the analogues are multitudinous. See, for 
 example, the spikes of the Spanish and Horse Chestnuts, and 
 especially the hair-like but formidable bristles which defend 
 the common Prickly Pear. Indeed, all that tribe of plants is 
 furnished so abundantly with natural ranjows, that a hedge of 
 prickly pear forms the best defence which a house and garden 
 can have. 
 
 Another example of natural ranjows is seen in the Tree-caddis, 
 one of which is shown in the illustration on page 108, as it 
 appears when suspended from a twig. It is the work of one of 
 the House-builder Moths of the West Indies, and forms a sort 
 of house in which the caterpillar can rest securely. It is built of 
 bits of twigs and thorns, the latter being disposed so that their 
 points are outwards, much after the fashion of a hedgehog's 
 spines. 
 
 I possess many specimens of Tree-caddis, evidently belonging 
 to several species, and in all of them the principle is the same, 
 i.e. a number of spikes set with their ends outwards in order 
 to defend a central position. 
 
 Sometimes these spikes are left exposed, as shown in the 
 illustration, and sometimes they are covered with a slight but 
 strong web. The principle, however, is the same in all. 
 
 Now I shall have to use two very long words, and much 
 against my will. I very much fear that, if most of my readers 
 were to hear any one speak of the " repagula of Ascalaphus," 
 they would not be much the wiser. And yet there are no 
 other words that can be used. 
 
 In the first place, Ascalaphus is a name belonging to a 
 genus of Ant-lions, remarkable for having straight, knobbed 
 antennae, very much like those of a butterfly. This insect 
 deposits its eggs in a double row on twigs, and then defends 
 them with a series of natural ranjows, set in circular rows, 
 and supposed to be without analogies in the animal creation. 
 They are transparent, reddish, and " are expelled by the 
 female with as much care as though they were real eggs, and 
 are so placed that nothing can approach the brood ; nor can 
 the young ramble abroad until they have acquired strength to 
 resist the ants and other insect enemies." 
 
 The word "repagulum," by the way, signifies a bar or barrier.
 
 112 
 
 NATURE S TEACHINGS. 
 
 A turnpike gate when closed would be a repagulum, and so 
 would a chevaux-de-frise. 
 
 TEARING WEAPONS. 
 
 WE have already had examples of weapons, like the Club, 
 which bruise ; of weapons, like the Spear and Dagger, which 
 pierce ; and of weapons, like the Sword, which cut. We now 
 come to a totally distinct set of weapons, those which wound 
 by tearing, and not by any of the preceding modes. 
 
 In civilised warfare we have long abandoned such weapons, 
 as belonging to a barbarous age, but they are even yet em- 
 ployed in some parts of the world. 
 
 The accompanying illustration shows three examples of such 
 weapons. One is the celebrated Tiger-claw of India, known 
 by the native name of Wag-nuk. It is about two inches and a 
 half in length, and is made to fit on the hand. The first and 
 fourth fingers are passed through the rings, and the curved 
 claws are then within the hand, and hidden by the fingers. 
 The mode of employing this treacherous weapon was by 
 
 WAGr-NUK OF INDIA. 
 
 HIND-CLAWS OP TIGEB. 
 
 CLAWED GAUNTLET. 
 SHARK-TOOTH GAUNTLET. 
 
 engaging a foe in conversation, pretending to be very friendly, 
 and then ripping up his stomach with an upward blow of the 
 right hand.
 
 THE TOOTHED GAUNTLET. 113 
 
 It is comparatively a modern weapon, having been invented 
 about two hundred years ago. A Hindoo, named Sewaja, was 
 the inventor, and by means of the Wag-nuk he committed many 
 murders unsuspected, the wounds being exactly like those 
 which are made by the claw of the tiger. Sometimes there 
 were four claws instead of three, as is the case with a specimen 
 one in the Meyrick collection. 
 
 Perhaps the reader may be aware that the Transatlantic 
 " knuckle-duster " is fitted on the hand in the same manner, 
 only its object is to strike a heavy blow, and not to tear. History 
 repeats itself, and the large and clumsy " cestus " of the ancient 
 athlete is reproduced in the small but scarcely less formidable 
 " knuckle-duster" of the modern rowdy. 
 
 The figures are remarkable, one representing the remaining 
 epoch of chivalry, and the other that of barbarism. The upper 
 figure shows a curious Gauntlet of the Middle Ages, in which 
 the hand is not only defended by steel plates, but is also 
 rendered an offensive weapon by the addition of four sharp 
 spikes set just at the junction of the fingers with the hand. 
 As long as the fingers are extended the spikes lie parallel with 
 them, and are as harmless as a cat's claws in their sheaths. 
 But when the fingers are closed, as shown in the illustration, 
 the spikes come into use, and can be made into a formidable 
 weapon of offence, just as are the cat's claws when protruded. 
 
 BELOW the gauntlet of civilised warfare is one of savage war, 
 which has for many years been discontinued, partly on account 
 of the introduction of firearms, and partly owing to the super- 
 ficial coating of civilisation which is so easily adopted by the 
 singular varieties of the human race which populate the isles 
 where this remarkable weapon was once worn. The figure is 
 taken from a specimen in the United Service Museum. 
 
 It is a Gauntlet, having at one end a band through which 
 the whole hand is passed, and at the other three loops for the 
 fingers, just like those of the Wag-nuk, which has already been 
 described. The body of the weapon is made of cocoa-nut fibre, 
 and upon it are strung six rows of sharks' teeth, the tips all 
 pointing backwards. It is a Samoan weapon, some of the 
 most renowned warriors never using club nor spear, but 
 trusting entirely to their terrible gauntlets. "With these they
 
 114 NATURE'S TEACHINGS. 
 
 struck right and left, dashing beneath the cluhs and spears of 
 their enemies, and always trying to rip up their stomachs, 
 just as is done with the Wag-nuk. In order to guard against 
 this weapon, the Samoan warrior wears a helt of cocoa-nut fibre 
 some eight inches wide, and thick enough to defy the best 
 gauntlet that could be made. 
 
 One celebrated Samoan warrior, a man of gigantic stature 
 and strength, was addicted to the amusement of seizing his 
 enemies with the shark-tooth gauntlets, breaking their backs 
 across his knee, throwing them down, and going off after 
 another victim. 
 
 ON the left hand of the illustration is seen the hind-foot of 
 the Tiger. I have chosen the hind-foot for two reasons: firstly, 
 because the fore-foot has already been figured ; and secondly, 
 because the hind-foot is used for tearing open the abdomen of 
 the prey. Any one who has played with a kitten has noticed 
 how the animal throws itself on its back, clasps the wrist with 
 its fore-paws, and kicks vigorously with its hind-legs. It does 
 not mean to hurt its playfellow, but the hand does not easily 
 escape without sundry scratches. 
 
 Child's play though it may be in the kitten, it is no play at 
 all with the tiger, or even the leopard, for either of these 
 animals, when hard pressed, will throw itself on its back, 
 clasp the foe in its fore-paws, and with the talons of the hind- 
 feet tear him to pieces.
 
 WAE AND HUNTING. 
 
 CHAPTER VI. 
 
 THE HOOK-DEFENSIVE ARMOUR. THE FORT. 
 
 Anglers and their Hooks. Single and double Hooks. Hook of British Columbia. 
 Seed of Galium, or Goose-grass, and its Armature of Hooks. Seed of the 
 Burdock, and its Annoyance to Sheep. Hooked Sponge- spicules. "Snatch- 
 ing " Fish. The Fish-rake of British Columbia. The ' Gaff" and its Uses. 
 The Jaguar as a Fisher Defensive Armour and its Varieties. Plate and 
 Chain Mail. The Shield. Australian and West African Shields. Fibre 
 Armour. Seal's-tooth Cuirass. Joints of Armour. " Tassets." Scale 
 Armour in Art and Nature. The Manis and the Fish. Feather Armour. 
 "Madoc in Aztlan." Quilted Armour of Silk or Cotton. Terrible Results 
 from the latter. Mr. Justice Maulstatute. Natural Quilt Armour. The 
 Rhinoceros and the Whale. The Testudo of the ancient Romans, and its 
 Uses. The common Tortoise. The Fort. Curious Transitions in Fort- 
 building ; first Earth, then Stone, then Earth again. Advantage of Earthen 
 Mounds. Natural Snow-fort made by the Elk, and its Defensive Powers 
 against the Wolf. 
 
 THE HOOK. 
 
 TAVINGr now seen that the rod and line of anglers have 
 *-*- their prototypes in Nature, we will proceed to the hook, 
 by which the fish are secured. 
 
 The two figures on the right hand of the accompanying 
 illustration represent hooks which are familiar to every angler. 
 The lower is the ordinary fish-hook, which can be used in so 
 many ways. Generally it is employed singly, being fastened 
 to the end of a line, and armed with a bait, either real or 
 artificial. Sometimes, however, these hooks are whipped 
 together, back to back, three or even four being so employed, 
 and thus forming a combination of the hook and grapnel, and 
 rendering the escape of a fish almost impossible. 
 
 Above it is a double hook, such as is used in " trolling " for 
 
 i 2
 
 116 
 
 NATURE S TEACHINGS. 
 
 pike, and with the use of which many of my readers are 
 probably acquainted. 
 
 The third is a singularly ingenious hook made by the 
 natives of British Columbia. It is almost entirely made of 
 wood, with the exception of the barb, which is of bone. 
 This, as the reader will see, is fixed, not to the point of the 
 hook, as with us, but to its base, the point being directed 
 towards the central portion of the curve. 
 
 At first sight this seems to be a singular arrangement, but it 
 is a very effective one, as any one may see by placing the 
 
 HYMEDESMIA. 
 
 FRUIT OF OALIUM. 
 
 VANCOUVER HOOK. 
 
 DOUBLE AND 
 SINGLE HOOKS. 
 
 point between the fingers and pushing it through them. It 
 will be found impossible to force it back again, the sharp point 
 of the bone-barb coming against them and retaining them. 
 
 It has also another advantage. Very large fish, for which 
 this hook is intended, are apt in their struggles to reverse the 
 hook, and so to weaken its hold. In this hook, however, such 
 a proceeding is impossible ; for, even should the hook be 
 reversed, it still retains its hold, the barb becoming the point, 
 and the point keeping the lip of the fish against the tip of the 
 barb. The figure is drawn from a specimen in my collection. 
 
 IF the reader will look at the illustration, he will see a 
 globular object covered with little hooks. This is a magnified 
 representation of the seed-vessel of the common Goose-grass 
 (Galium), which is so luxuriant in our hedges, and often 
 intrudes itself into our gardens. Its long, trailing stems, with 
 their tightly-clinging leaves, are familiar to all, and there are 
 few who have not, while children, pelted each other with the
 
 SPONGE-SPICULES. 117 
 
 little round green seed-vessels during the time that the fruit is in 
 season. That they clung so tightly as not to be removed without 
 difficulty, we all knew, but we did not all know the cause. The 
 magnifying-glass, however, reveals the secret at once. The 
 whole of the surface is covered with little sharp prickles, 
 curved like hooks, and turned in all directions, so that, however 
 it may be thrown, some of them are sure to catch. 
 
 So readily do these hooks hold to anything which they 
 touch, that if a lady only sweeps her dress against a plant of 
 Goose-grass, she is sure to carry off a considerable number of 
 the seed-vessels, and to waste much time afterwards in picking 
 them off. 
 
 The seed-vessel of the common Burdock, known popularly 
 by the name of Bur, is armed in a similar manner, but, as it 
 is much larger, it is easily avoided. Sheep suffer greatly from 
 burs, which twist themselves among the wool so firmly that it 
 is hardly possible to remove them without cutting away bur 
 and wool together. As to a Skye terrier, when once he gets 
 among burs, his life is a misery to him (I was going to say, a 
 burden to him, but it would have looked like a pun). 
 
 Below, and on the left of the Galium-seed, are some spicules 
 of the Hymedesmia, a sponge which is found on the coast of 
 Madeira. The following account of it occurs in the Intel- 
 lectual Observer, vol. ii. p. 312 : 
 
 " FISH-HOOK SPICUL^E. We have received from Mr. Baker, 
 of Holborn, a slide containing spicules of the Hymedesmia 
 Johnsonii, which are stated to be rare objects in this country. 
 They have the form of a double fish-hook, and on the inner 
 surface of each hook is an extremely sharp knife-edge pro- 
 jection, corresponding with a similar and equally sharp 
 projection from the inside of the shank. 
 
 " These minute knife-blades are so arranged that in addition 
 to their cutting properties, they would act as barbs, obstructing 
 the withdrawal of the hook. The two hooks attached to one 
 shank are not in the same place, but nearly at right angles 
 with one another, so that when one is horizontal the other is 
 vertical, or nearly so. A magnification of four or five hundred 
 linear does not in any way detract from the sharp appearance 
 of the knife-edges, and they may take their place with the
 
 118 
 
 NATURE S TEACHINGS. 
 
 anchors of the Synapta as curious illustrations of the occurrence 
 in living organisms of forms which man was apt to fancy were 
 exclusively the products of his own contrivance and skill. 
 
 " We presume that these hooks of the Hymedesmia answer 
 the usual purpose of spiculae in strengthening the soft tissue, 
 but they must likewise render the sponge an awkward article 
 for the Madeira sea-slugs to eat." 
 
 For an account and figures of the Synapta anchor- spicules 
 see page 39. 
 
 WE now come to another modification of the hook. I pre- 
 sume that many of my readers have heard of the practice 
 called " snatching " fish, though I hope that they have never 
 been unsportsmanlike enough to follow it. 
 
 This plan, which is only worthy of poachers, consists in 
 taking several flights of treble or quadruple hooks, dropping 
 them gently by the side of the fish, and then, with a sudden 
 jerk, driving them into any part of its body which they may 
 happen to strike. Most anglers have snatched fish accidentally, 
 but to do so intentionally is ranked among the worst of an 
 angler's crimes, and is equivalent to cheating at cards, or 
 playing with false dice. 
 
 In some parts of the world, however, there are certain 
 small fish which are never taken in any other way, and, indeed, 
 are raked out of the water just as a gardener rakes dead leaves 
 off the path or beds. 
 
 JAGUAE AXD CLAW. 
 
 FISH-RAKE. 
 
 In British Columbia there are certain lakes tenanted largely 
 with small fish which form a considerable portion of the
 
 FISH-RAKE AND GAFF. 119 
 
 natives' diet. They swim in vast shoals close to the surface of 
 the water, and are captured by veritable rakes, one of which is 
 shown in the illustration. The points of the rake are slightly 
 curved, and very sharp, and so numerous are the fish that 
 when the native has struck his rake among the shoal, and 
 drawn it into the boat, he generally finds a fish on every tooth, 
 while it often happens that two or three are transfixed by the 
 same tooth. A sharp knock against the side of the boat shakes 
 off the prey, and the fisherman again strikes his rake into the 
 shoal. By this simple mode of fishing a couple of men will, 
 in a few hours, load a canoe with small but valuable fish. 
 
 Below the rake is the " Gaff," an instrument, not to say a 
 weapon, which is indispensable when salmon or other large fish 
 are to be caught. For ordinary- sized fish a landing-net is suf- 
 ficient, but no landing-net could either receive or retain a 
 salmon of any size. 
 
 Recourse is then had to the Gaff, which is simply a huge 
 hook at the end of a handle. The fish being " played " until it 
 can be drawn within reach, the gaff is slipped under it, struck 
 into the side of the salmon, and by its aid the fish is easily 
 lifted out of the -water. 
 
 ON the left hand of the illustration are two figures showing 
 how the principle of the fish-rake and gaff has been anticipated 
 in Nature. 
 
 It is a well-known fact that the Jaguar feeds largely on 
 fish, which it catches for itself. It goes down to the river-side 
 as close to the water as possible, and waits patiently for its 
 prey. As soon as a fish comes within reach, the Jaguar 
 stretches out its paw to the fullest extent, and, with a stroke of 
 the curved claws, hooks the fish on shore, just as the Vancouver 
 Islander does with his fish-rake, or the 'English angler with his 
 gaff 
 
 Many persons have practically experienced the gaff-like 
 powers of the feline claw by the loss of their gold-fish. It is 
 seldom safe to leave a globe of gold-fish within reach of a cat. 
 Nearly all cats are madly fond of fish, and, in spite of their 
 instinctive hatred of water, will hook out the fish with their 
 claws, and eat them. Indeed, there are several instances on 
 record where a cat has regularly caught fish, and brought them
 
 120 
 
 NATURE S TEACHINGS. 
 
 home to its owner. Mr. F. Buckland gives an account of a 
 fisherman's cat, which used to go out with her master, jump 
 into the sea, secure a fish, and then be lifted on board with 
 her prey. 
 
 Above the Jaguar is drawn a single claw, so as to show the 
 form of the instrument by which the fish is captured. 
 
 ARMOUR. 
 
 WE will now take the subject of Defensive Armour, by 
 which warriors are enabled to protect themselves against the 
 offensive weapons of the enemy. 
 
 As many readers will probably know, armour reached its 
 greatest development in the Middle Ages, when the knight was 
 so completely cased in steel that no weapon then in use could 
 penetrate his panoply. 
 
 The head, body, and limbs were covered with steel plates 
 curiously articulated at the joints, so as to give freedom of 
 motion, while guarding the wearer from any ordinary weapon. 
 A warrior might be beaten from his horse by a mace, or struck 
 down by a lance, or the horse itself might be killed under 
 him. 
 
 In either of these cases the fallen knight was not much the 
 worse, until a weapon called the " Misericorde," or dagger of 
 
 LOBSTBH. 
 AKU.M tUG. 
 
 PLATB AND SCALE ABMOUB 
 OF MIDDLE AGES. 
 
 riCHICIAGO. 
 
 mercy, was invented. This was a poniard with a very slender 
 and very sharp blade, so constructed that it could be driven
 
 DEFENSIVE ARMOUR. 121 
 
 between the joints of the armour, and thus inflict a mortal 
 wound. The Misericorde, however, was baffled by the use of 
 chain or scale armour under the plate-mail, and then the only 
 way of getting at the fallen knight was by breaking up the 
 armour with hammers which were made for this express 
 purpose. 
 
 Perhaps the reader may wonder that any one should lie 
 quietly and allow himself to be so badly treated. The very 
 strength of the armour, however, which rendered its wearer 
 unassailable by ordinary weapons, involved so much weight, 
 that when a knight had fallen, it was impossible for him to 
 rise, much less to mount a horse, without help. Moreover, the 
 first blow of a weighty hammer on the helmet would, although 
 it could not kill the wearer, cause such a jar to his brain as 
 partially, if not wholly, to stun him. 
 
 The rapidly increasing power of firearms soon caused armour 
 to be laid aside, and now the only remains of it are to be found 
 in the helmets and cuirasses worn by our dragoons. 
 
 THERE are few parts of the world where armour of some 
 sort is not used. Putting aside civilised or semi- civilised 
 nations, we find that in most cases, wherever there is war, there 
 is armour of some kind. Sometimes it is movable, and in that 
 case is called a shield. 
 
 The most singular shields that I know are those made by the 
 Australians, which are so shaped that no one who did not 
 know their use would take them for shields. They are about 
 three feet long, four inches wide at the back, six inches or so 
 thick in the middle, tapering towards the ends, and coming 
 to an edge in front. They are held by the centre with one 
 hand, so that they can be rapidly twisted from side to side, 
 and so serve to parry the spear or stop the boomerang. The 
 weight of the shield enables it to withstand the shock of the 
 boomerang, which whirls through the air with terrific force. 
 
 Several warlike savage tribes have, however, no armour of 
 any kind, such as the New Zealanders, the Samoans, and the 
 Pijians. 
 
 Sometimes the armour is affixed to the body, and of such 
 protection many examples are to be found in various museums, 
 among which the Christy collection is pre-eminent.
 
 122 NATURE'S TEACHINGS. 
 
 Among the Polynesians cocoa-nut fibre was at one time 
 employed as the material for armour. It was twisted into 
 small cords, and with these a sort of armour was constructed, 
 quite strong enough to resist any weapon that an enemy of their 
 own kind could bring against them. Sometimes this armour was 
 merely a belt wide enough to protect the abdomen, but some- 
 times the whole body was defended, from the neck to the hips. 
 
 In the United Service Museum there is a very remarkable 
 cuirass, which is made of successive rows of seals' teeth, each row 
 overlapping the other like the tiles of a house. It is very heavy, 
 weighing quite as much as a steel cuirass, and was probably 
 quite as effective against the primitive weapons which could be 
 brought to bear upon it. 
 
 Now for Natural Armour. 
 
 There are so many examples of armour, as furnished by 
 Nature, that I can only mention a few. 
 
 Any one who looks at a lobster, crayfish, prawn, or shrimp, 
 must at once see that in it lies the prototype of plate 
 armour. That portion of the lobster which is popularly called 
 the head, and is scientifically known as the " carapace," is not 
 jointed, and corresponds with the cuirass of ancient or modern 
 armour. Then comes the part called the " tail," the joints of 
 which are exactly like those employed in the shoulders, elbows, 
 knees, and ankles of ancient armour. The lobster tail will again 
 be mentioned in connection with another branch of human art. 
 
 As for the heavy, ungraceful armour which was used in 
 tilting, we have an admirable example in the Trunk-fish of the 
 tropical seas (Ostraaon), the whole of which is enclosed in a 
 bony case, the fins and tail protruding through openings in it. 
 In fact, the scales, instead of being separate, are fused together 
 so as to form a continuous covering. The Box-tortoise of 
 South America is another good example, the creature being 
 furnished with bony flaps with which it covers the apertures 
 through which the head, legs, and tail are protruded, and so is 
 as impervious as the knight of old. 
 
 In the later ages of armour, the thighs, instead of being 
 enclosed in steel coverings with cuisses, were defended by a 
 number of steel plates called " tassets." Now these tassets are 
 exactly like the defensive armour of the Armadillo's back, and,
 
 NATURAL ARMOUR. 123 
 
 though it is not likely that the inventor of t assets should have 
 seen an Armadillo, the fact still remains, that Art has been 
 anticipated by Nature. 
 
 Exactly the same principle is seen in that wonderful little 
 animal, the Pichiciago of South America, which is shown in the 
 lower left-hand figure of the illustration. This creature is not 
 only furnished with bony rings on the body like those of the 
 Armadillo, but has likewise a flap which comes over the hind- 
 quarters, and effectually defends it against the attacks of any 
 foe that might pursue it into its burrow. 
 
 In the lower right-hand corner of the illustration is seen a 
 figure of a Chiton, several species of which are common on most 
 of our coasts. This is one of the molluscs, which adheres to 
 the rock just as limpets do. But, whereas the shell of the 
 limpet is all in one piece and inflexible, that of the Chiton is 
 composed of several pieces, which are arranged exactly like the 
 tassets of armour, and enable the Chiton to accommodate itself 
 to the inequalities of the rocks to which it is adhering. 
 
 The common Pill Millipede, which rolls itself up in a ball 
 when alarmed, is a familiar instance of similar defensive armour, 
 and much the same may be said of the Julus Millipede. 
 
 WE now come to Scale Armour, which is one of the earliest 
 modes of protecting the body, and the idea of which was clearly 
 taken from animal life. In Scale Armour, flat plates of metal, 
 horn, or bone are sewn to a linen or leathern vest in such a 
 
 SCALES OP MARTS. SCALE-MAIL. 
 
 way that the scales overlap each other, and so tend to throw off 
 the blow of a weapon. One great advantage of this armour is 
 its lightness and flexibility, the former quality allowing of 
 more prolonged exertion than could be possible with the heavy 
 plate armour, and the latter rendering that exertion less 
 fatiguing to the limbs.
 
 124 
 
 NATURE S TEACHINGS. 
 
 A glance at tlie preceding illustration will show how the 
 scale armour of the human warrior has been anticipated by 
 Nature. 
 
 On the right hand is an example of ordinary scale armour, 
 while on the opposite side is a portion of a scaly surface. 
 This figure represents some of the scales of a Manis. These 
 scales are wonderfully hard, and scarcely to be penetrated. I 
 have in my collection the skin of a Short-tailed Manis, which 
 had been kept for some time in an Indian compound, but which 
 made itself such a nuisance by its perpetual burrowing, that 
 its owner was forced to condemn it to death. 
 
 So he took a Colt's revolver, and fired at it from a distance of 
 a yard or two. The only result was to knock over the Manis, 
 which rolled itself up, and appeared to be none the worse. A 
 second and a third shot were fired with similar results, and the 
 last bullet recoiled upon the firer. At last, the animal was 
 killed by introducing the point of a dagger under the scales, 
 and driving it in with a mallet. The Manis itself is given in 
 the illustration on page 189. 
 
 SKIN OF SINGLETHORN. 
 
 SCALE-MAIL. 
 
 Again, the scales of most fishes afford excellent examples of 
 scale armour. I have selected one, the Japanese Single thorn, 
 on account of the strength of the scales, each of which is deeply 
 ridged and furrowed. The reader will probably have noticed 
 that the skin of the animal, into which are inserted the bases 
 of the scales, is analogous to the linen or leathern foundation 
 upon which the artificial scales are sewn. 
 
 Even feathers give a better protection than might be 
 imagined from their individually fragile structure. This is 
 well shown in the case of aquatic birds, whose feathers are very 
 closely pressed together, each overlapping the next, and set in
 
 FEATHER ARMOUR. 125 
 
 regular order. Not only is the plumage rendered water-tight, 
 but it is able to resist a severe blow. This is well known by 
 sportsmen, who do not fire at ducks or geese while they are 
 approaching, knowing that their shot would only glide harm- 
 lessly from the feather-mail of the bird. 
 
 They wait until the birds have passed, and then find no 
 difficulty in killing them, the shot penetrating under the 
 feathers just as did the dagger under the scales of the manis. 
 Even the diminutive puffin, or sea-parrot, as it is sometimes 
 called, cares little for shot while it is sitting on the rocks with 
 closed wings and feathers pressed together. When, however, 
 it takes to flight, it can be killed without difficulty. 
 
 Perhaps some of my readers may be aware that the ancient 
 Mexican warriors wore armour made of feathers, which I pre- 
 sume must have been arranged much after the fashion of those 
 of a duck's breast. 
 
 This remarkable Feather-mail is mentioned by Southey in his 
 poem, " Madoc in Aztlan." In canto xviii. is recounted the 
 single combat between Madoc and Coanocotsin, the King of 
 Aztlan. The contrasting armour and weapons of each are 
 graphically described, and especial mention is made of the 
 cuirass : 
 
 " Over the breast, 
 
 And o'er the golden breastplate of the King, 
 A feathery cuirass, beautiful to eye, 
 Light as the robe of peace, yet strong to save ; 
 For the sharp faulchion's baffled edge would glide 
 From its smooth softness." 
 
 Then, in the course of the combat, when the King has been 
 grappled in Madoc's arms and forced to drop his buckler and 
 club, the narrative proceeds : 
 
 " Which when the Prince beheld, 
 He thrust him off, and drawing back, resumed 
 The sword that from his wrist suspended hung, 
 And twice he smote the King. Twice from the quilt 
 Of plumes the iron glides." 
 
 If such armour could in truth resist the weapons which have 
 been discovered, it must have been a wonderfully strong gar- 
 ment, for the Mexican swords, though made of wood, are edged 
 with flakes of obsidian, which cuts like a razor. I have a 
 number of these flakes, which have evidently been intended for 
 the edges of a sword, but have not been used.
 
 126 NATURE'S TEACHINGS. 
 
 THERE is another kind of armour which is still used in some 
 parts of the world, and at one time was employed in this 
 country. This is the Quilt Armour, which is made by enclosing 
 a thick layer of some fibre, such as silk or cotton, between two 
 pieces of fabric, and then sewing them across and across, so 
 as to keep the lining or stuffing in its place. 
 
 The eider-down quilts are familiar examples of such fabrics. 
 and so are the quilted petticoats, which are so comfortable in 
 winter. Horsehair and flock mattresses are made in a similar 
 manner. 
 
 Insufficient as it may appear to be, the quilt armour, when 
 well made, is really proof against most weapons, even against 
 firearms, as we shall presently see. Being very much lighter 
 than steel, it was easier for the wearer, its chief drawback 
 being that its extreme thickness gave it a very clumsy and 
 awkward look. Those who wore it, however, cared more for their 
 safety than their appearance, as was exemplified by James I., 
 who lived in perpetual fear of assassination, but who had a 
 nervous dislike to arms, whether offensive or defensive. He 
 therefore wore a cuirass quilted with silk, which answered 
 every purpose of defence, while it did not offend his nerves. 
 
 Perhaps the reader may remember that in " Peveril of the 
 Peak " Sir Walter Scott gives a ludicrous picture of the timid 
 justice, his fears of the Popish plot, his suit of quilted armour, 
 and his " Protestant Flail " with which he hits himself on the 
 head instead of striking his supposed enemy : 
 
 " Some ingenious artist, belonging, we may presume, to the 
 worshipful Mercers' Company, had contrived a species of armour 
 of which neither the horse armoury in the Tower, nor 
 Gwynnap's Gothic Hall, no, nor Dr. Meyrick's invaluable 
 collection of ancient arms, has preserved any specimen. 
 
 " It was called Silk-armour, being composed of a doublet and 
 breeches of quilted silk, so closely stitched, and of such thick- 
 ness, as to be proof against either bullet or steel, while a thick 
 bonnet of the same materials, with ear-flaps attached to it, and 
 on the whole much resembling a nightcap, completed the 
 equipment, and ascertained the security of the wearer from 
 the head to the knee. Master Maulstatute, among other worthy 
 citizens, had adopted this singular panoply, which had the 
 advantage of being soft, and warm and flexible, as well as safe.
 
 QUILTED ARMOUR. 127 
 
 And he was sat in his judicial elbow-chair a short, rotund 
 figure, hung round, as it were, with cushions, for such was the 
 appearance of the quilted garments and with a nose pro- 
 truded from under the silken casque, the size of which, together 
 with the unwieldiness of the whole figure, gave his worship no 
 indifferent resemblance to the sign of the Hog in Armour, which 
 was considerably improved by the defensive garment being of 
 a dusky orange colour, not altogether unlike the hue of those 
 half- wild swine which are to be found in the forests of Hamp- 
 shire." 
 
 Roger Nutt gives as a reason for the security of quilted 
 armour, that it made the wearer look so ridiculous that no 
 one could hit him for laughing. The reader will probably 
 remember that the sign of the Hog in Armour was really a 
 representation of the rhinoceros. 
 
 That such a cuirass is really impervious to ordinary weapons 
 is shown by the following anecdote : During one of the late 
 Indian wars a trooper discharged his pistol close to the back 
 of a fleeing horseman. The shot produced no apparent effect, 
 and the man rode off. Presently, however, a thin cloud of 
 smoke was seen to rise from his shoulders. The smoke 
 thickened, then burst into flame, and after riding at desperate 
 speed in" hopes of overtaking his comrades, the unfortunate 
 man fell from his horse, and was miserably burned to death. 
 
 The fact was that cotton being cheaper than silk, he had 
 wadded his cuirass with cotton fibre. Had he chosen silk, he 
 
 rS-niAM KIIJXOCEBOS. QUILTED ARMOUR. 
 
 would have got off in safety. Among the Chinese this cotton 
 mail is largely used. In consequence, many Chinese soldiers 
 were found who had been burned to death in exactly the same 
 way as the Indian warrior. 
 
 Towards the south-western parts of Africa there is a nation 
 called the Begharrnis. Their soldiers are mounted, and are all
 
 128 NATURE'S TEACHINGS. 
 
 furnished with suits of quilted mail, which fall below the knee 
 as the rider is seated on his horse. Not only is the rider thus 
 defended, but the horse also, which is covered with quilted 
 armour like that of its rider, the appearance of both being 
 exceedingly grotesque. 
 
 THERE are several examples of such armour in the animal 
 world, the principal of which is the Indian Rhinoceros. Any 
 one who has seen this animal, or even a good portrait of it, will 
 at once recognise the parallel between the heavy folds of its 
 thick skin and the padded flaps of the quilted mail. The 
 blubber with which the whale is so thickly coated affords 
 another example of the parallel between Nature and Art. 
 
 IN the days of ancient Rome there was a curious mili- 
 tary manoeuvre, by which the defensive armour of individual 
 soldiers might be made collectively useful. This manoauvre 
 was called Forming a Tortoise (testudinem facere), and is 
 thus described in Smith's " Dictionary of Greek and Roman 
 Antiquities :" 
 
 " The name of Testudo was also applied to the covering 
 made by a close body of soldiers, who placed their shields 
 over their heads to screen themselves against the darts of the 
 enemy. The shields fitted so closely together as to present 
 one unbroken surface without any interstices between them, 
 and were so firm that men could walk upon them, and even 
 horses and chariots be driven over them. 
 
 " A Testudo was formed either in battle, to ward off the 
 arrows and other missiles of the enemy, or, which was more 
 
 ROMAN TKSTCDO. 
 
 frequently the case, to form a protection to the soldiers when 
 they advanced to the walls or gates of a town for the purpose 
 of attacking them.
 
 THE FORT. 129 
 
 " Sometimes the shields were disposed in such a way as to 
 make the Testudo slope The soldiers in the first line stood 
 upright, those in the centre stooped a little, and each line 
 successively was a little lower than the preceding, down to the 
 last, where the soldiers rested on one knee. Such a disposition 
 of the shields was called Fastigata Testudo, on account of their 
 sloping like the roof of a building. 
 
 " The advantages of this plan were obvious. The stones and 
 missiles thrown upon the shields rolled off them like water 
 from a roof ; besides which, other soldiers frequently advanced 
 upon them to attack the enemy upon the walls. The Romans 
 were accustomed to form this kind of Testudo as an exercise 
 in the games of the Circus." 
 
 On the right hand of the illustration is shown a portion of 
 a Testudo of three ranks, taken from the Antonine column. 
 On the left is an ordinary Tortoise. Sometimes the Testudo 
 was a covered machine on wheels, and guarded above with a 
 supplementary roof of wet hides arranged in scale fashion, so 
 as to prevent it from being set on fire by the besieged, and 
 to throw off the heavy missiles which were dropped upon it. 
 Under cover of this Testudo, the soldiers could either under- 
 mine the walls, or bring a battering-ram to bear upon them, 
 while the men who worked it were safely under cover. As to 
 the battering-ram itself, we shall presently treat of it. 
 
 THE FORT. 
 
 As we have treated of one of the modes by which Forts were 
 assaulted, we will now come to the Fort itself. 
 
 The transitions in Fort-making are too curious to be omitted 
 from the present book. As soon as war became organized, 
 a Fort of some kind was necessary. The simplest mode of 
 making a Fort wa"s evidently to dig a deep trench, and throw 
 up the earth on the inside, so as to form a wall. Let such a 
 trench be square or circular, and there is a simple but powerful 
 Fort, by means of which a comparatively small garrison could 
 defend themselves against a superior force. 
 
 The Romans were great masters of this art, fighting as much 
 with the spade as the sword. So strong and thorough was the 
 old Roman work that many of their camps still remain, and will 
 
 K
 
 130 NATURE'S TEACHINGS. 
 
 remain for centuries if man does not deface tnem. Such, for 
 example, are Caesar's camp, near Aldershot, and the fine camp 
 at Lyddington, in Wiltshire, almost every detail of which is 
 preserved. Roman camps are all constructed on the same 
 model, the general's place, or Prsetorium, being in the centre, 
 whence he issued his orders, and the commanders under him 
 occupying the corners. Thus, no matter how he might be 
 shifted from one corps to another, every Roman soldier knew 
 his way about the camp without needing to see it, and could 
 tell at any moment where to find any ofiicer. 
 
 ELK FORT. MOUND FORT. 
 
 Other nations made their Forts circular, an example of which 
 I lately saw a few miles from Bideford, while others consisted 
 of nearly parallel lines, enclosures, and demi-lunes, like those 
 vronderful dykes near Clovelly, which occupy more than thirty 
 acres of land. One of the circular Forts is shown on the right 
 hand of the illustration. 
 
 As time went on, stone took the place of earth, and the prin- 
 cipal object of the builder was to give considerable thickness 
 below, so as to resist the battering-ram, and great height both 
 to walls and towers, so as to be comparatively out of the reach 
 of the arrows and other missiles of the besiegers. 
 
 For awhile, such castles were impregnable, and the owners 
 thereof were the irresponsible despots of the neighbourhood, 
 recognising no law but their own will, robbing, torturing, and 
 murdering at pleasure, and setting the king at open defiance. 
 When, however, the tremendous powers of artillery became 
 developed, the age of stone castles passed away. Height was 
 found to be equivalent to weakness, as the strongest tower in 
 existence could be knocked to pieces in an hour or two, and do 
 infinite harm within the fortress by its falling fragments. 
 
 Fortification then returned to its original principles. Earth 
 took the place of stone or brick ; and at the present day,
 
 THE ELK-YARD. 131 
 
 instead of erecting lofty walls and stately towers, the military 
 engineer sinks his buildings as far as he can into the ground, 
 and protects them with banks of simple earth, which is found 
 to be the best defence against heavy shot. There is no 
 masonry in existence that will endure the artillery fire of the 
 present day, and even the solid rock can be knocked to pieces by 
 it. But an earth-mound is a different business, and will absorb 
 as many shot and shell as can be poured into it, without being 
 much the worse for it. See, for example, the Proof-mound at 
 Woolwich, which receives the shot of guns as they are being 
 proved. Now, this mound has undergone perpetual battering 
 for many years, and is as strong as ever. The same thing may 
 be said of the celebrated Mamelon before Sebastopol. 
 
 So much for the Fort made by the hand of man. "We now 
 come to that which is formed by the feet of animals. 
 
 The Elk, or Moose, an inhabitant of Northern Europe, finds 
 itself in great danger during the winter, the wolves being its 
 chief enemies. At certain times of the year there comes a 
 partial thaw during the day, followed by a frost at night. The 
 result is, that a slight cake of ice forms on the surface of the 
 snow, too slight to bear the weight of so heavy an animal, and 
 strong enough to cut the legs of the elk as it ploughs its way 
 along. Now, the wolves are sufficiently light to pass over the 
 frozen surface without breaking it, and accordingly, they can 
 easily run down and secure the elk. 
 
 In order, therefore, to counteract the wolves, a number of 
 elks select a convenient spot where they can find food, and 
 unite in trampling the snow down so as to sink themselves 
 nearly to their own height below its surface. The wolves never 
 dare attack an Elk-yard, as this enclosure is termed. In the 
 first place, they are always haunted with suspicions of traps, 
 and do not like the look of the yard ; and in the next place, if 
 some of the wolves did venture within the fort, the elks would 
 soon demolish them with hoofs and horns. One of these Elk- 
 yards is seen on the left hand of the illustration. 
 
 K2
 
 WAR AND HUNTING. 
 
 CHAPTER VII. 
 
 SCALING INSTRUMENTS. DEFENCE OP FORT. IMITATION. 
 THE FALL-TRAP. 
 
 Scaling-forks. The Climbing-spur and it8 Use. Larva of the Tiger-heetle. 
 Hooks of Serpula. Mr. Gosse's Description. Falling Stones. A Stone roll- 
 ing down a Precipice. The Polar Bear and the Walrus. Imitation. The 
 Polar Bear and the Seal. The Esquimaux Hunter " Seal-talking." En- 
 ticing Mother by means of Young. The Fall-trap and its Variations. The 
 Schoolboy's "Booby-trap." Curious Mode of killing Elephants. The Ele- 
 phant-spear. The Hippopotamus-trap of Southern Africa. The Mangrove 
 and its Seeds. The Spring-gun and Spring-bow. 
 
 "OEFORE dismissing the subject of the Fortress, we will 
 J-' glance at the Attack and Defence, as seen in Nature 
 and Art. 
 
 SCALING INSTRUMENTS. 
 
 WE have already seen how the Battering-ram could be 
 worked against the walls of a fort, or how the assailants could 
 scale them by means of the Testudo. There must, however, be 
 occasions when it would be impossible to bring together a 
 sufficiently large body of men to form the Testudo, or even to 
 place ladders, and in such instances it would be necessary that 
 each soldier should be furnished with an instrument by which 
 he could haul himself up the wall. 
 
 There are many examples still extant of such weapons, which 
 were called " Scaling-forks," and their general appearance 
 may be known by the two right-hand figures of the cut. The 
 handles of these weapons were very long, and by them the
 
 SCALIXG-FORK AND CLIMBING-SPUR. 
 
 133 
 
 soldier hauled himself to the top of the wall. In some of these 
 instruments the shafts were armed with projecting pegs, set at 
 regular intervals, so that they acted as the steps of a ladder, 
 and rendered the ascent comparatively easy. 
 
 Many of the long-handled partisans, such as the well-known 
 Jedwood axe, were furnished with a hook upon the back of the 
 blade, so that the weapon served the purpose of a scaling-fork 
 as well as a battle-axe. 
 
 The Scaling-fork (German Sturmgabel), which is shown on 
 the right hand of the illustration, was in use somewhere about 
 A.D. 1500. That which is shown next to it is about a hundred 
 years later. 
 
 Demmin, from whose work these figures are taken, mentions 
 that at the siege of Mons, in 1691, the grenadiers of the elder 
 
 WAI.KUS TUSKS. LARVA OF TIGER-BEETLE. CLIMBING-SPUR. SCALIXG-FOBKS. 
 
 HOOKS OP SEBPULA. 
 
 Dauphin's regiment stormed the walls under the command of 
 Vauban, and, by means of the Scaling-fork, carried the breast- 
 work, which they assaulted. As a mark of honour to these 
 gallant men, Louis XIV. ordered that the sergeants of the 
 regiment should carry scaling-forks instead of halberds, which 
 had been the peculiar weapon of the sergeant until compara- 
 tively late days, just as the spontoon, or half-pike, was the 
 weapon of the infantry officer from A.D. 1700 to A.D. 1800, or 
 thereabouts. 
 
 The English student will remember that in the writings of 
 Sterne, Fielding, and Smollett the half-pike is frequently
 
 134 NATURE'S TEACHINGS. 
 
 mentioned as the weapon of a subaltern officer. Demmin staies 
 that the last spontoons used in France were carried by the 
 French Guards in 1789. 
 
 PERHAPS the Climbing- spur may be familiar to some of my 
 readers, and bring back a reminiscence of boyhood. There is 
 nothing more tantalising to a boy than to see a hawk, or mag- 
 pie nest at the top of a tree which is too large to be climbed in 
 the ordinary way, and which has no branches within many feet 
 of the ground. However, boyish ingenuity has brought almost 
 any tree within the power of a bird's-nester by the invention of 
 the Climbing-irons. 
 
 These are made so as to pass under the foot like a stirrup, 
 and can be secured to the leg by leathern straps, the hooks 
 being, of course, on the inside of the leg. The cut represents 
 the Climbing-iron of the right leg. By means of these instru- 
 ments, a very large tree can be mounted, the irons being struck 
 firmly into the bark, and the legs moved alternately, and not in 
 the usual manner of climbing. Sometimes the hook of the 
 Climbing-iron is terminated by a single instead of & double 
 point, but the principle is the same in all. 
 
 WE will now look for similar examples in Nature. 
 
 On the right of the left-hand group is shown the larva or 
 grub of the common Tiger-beetle, which is itself a curious 
 creature. 
 
 It lives in perpendicular burrows, feeding upon those insects 
 which come within its reach. Its usual position is at the upper 
 part of the burrow, with its jaws widely extended, so as to 
 snap up any insect that may venture too near. 
 
 When it has secured its prey, it seeks the bottom of its 
 burrow, makes its meal in quiet, and reascends. How it does 
 so we shall soon see. Towards the end of the body, one of the 
 segments is much enlarged, and has a bold prominence upon 
 the back. On the summit of this prominence there are two 
 horn-like hooks, shaped as seen in the illustration. These 
 hooks are used exactly like the boy's climbing-spurs, the 
 alternate elongation and contraction of the body answering the 
 same purpose as the movements of the boy's legs. When the 
 larva has seized its prey and wishes to retreat, all that it has to
 
 HOOKS OF THE SERPULA. 135 
 
 do is to withdraw the hooks, straighten the body, and down it 
 falls by its own weight. 
 
 IN the nautical branch of this subject I have already treated 
 of the curious pushing-poles by means of which the Serpula 
 protrudes itself from its tube. As all must have noticed who 
 have seen these creatures alive, the Serpula protrudes itself very 
 slowly, but flies back into its tube with such velocity that the 
 eye can scarcely follow its movements. Its difference of motion 
 shows that there must be a difference in the means by which 
 these movements are produced. 
 
 Referring to the illustration on page 45, the reader will see 
 that the instruments with which the Serpula propels itself are 
 used just after the fashion of punt-poles, and cannot act with 
 any great swiftness. When, however, the creature wishes to 
 withdraw itself, it employs a curious apparatus, consisting of 
 many rows of little hooks. The points of these hooks readily 
 catch against the lining of the tube, and by their aid the worm 
 jerks itself back with wonderful celerity. 
 
 Three rows of these hooks are shown next to the Tiger-beetle 
 larva. 
 
 The structure of these remarkable organs is elaborately de- 
 scribed by Mr. Gosse in his " Evenings with the Microscope:" 
 
 " If you look again at this Serpula recently extracted, you 
 will find with a lens a pale yellow line running along the upper 
 surface of each foot, transversely to the length of the body. 
 This is the border of an exceedingly delicate membrane, and, 
 on placing it under a high power (say six hundred diameters), 
 you will be astonished at the elaborate provision here made for 
 prehension. 
 
 " This yellow line, which cannot be appreciated by the un- 
 assisted eye, is a muscular ribbon, over which stand edgewise a 
 multitude of what I will call combs, or rather subtriangular 
 plates. These have a wide base, and the apex of the triangle 
 is curved over into an abrupt hook, and then this cut into a 
 number (from four to six) of sharp and long teeth. 
 
 " The plates stand side by side, parallel to each other, along 
 the whole length of the ribbon, and there are muscular fibres 
 seen affixed to the basal side of each plate, which doubtless 
 give it independent motion.
 
 136 NATURE'S TEACHINGS. 
 
 " I have counted one hundred and thirty-six plates on one 
 ribbon. There are two ribbons on each thoracic segment, and 
 there are seven such segments. Hence, we may compute the 
 total number of prehensile comb-like plates on this portion of 
 the body to be about one thousand nine hundred, each of which 
 is wielded by muscles at the will of the animal ; while, as 
 each plate carries on an average five teeth, there are nearly ten 
 thousand teeth hooked into the lining membrane of the cell, 
 when the animal chooses to descend. 
 
 " Even this, however, is far short of the total number, be- 
 cause long ribbons of hooks of a similar structure, but of smaller 
 dimensions, run across the abdominal segments, which are 
 more numerous than the thoracic. No wonder, with so many 
 muscles wielding so many grappling-hooks, that the descent is 
 so rapidly effected." 
 
 Lastly, we come to the Walrus, whose strangely elongated 
 upper canine teeth can be used for just the same purposes as 
 the scaling- fork or climbing-spur. As, however, reference has 
 already been made to these tusks, in connection with another 
 department of this work, there is no necessity for occupying 
 space with a second description. 
 
 DEFENCE OF 'FoRT. 
 
 So much for attack ; now for defence. 
 
 The simplest mode of defending a fort, or even a mountain 
 pass, is by throwing or rolling rocks and heavy stones against 
 the enemy. 
 
 Simple as it may appear, it is a very effective one, as can be 
 well understood by those who have rolled a huge stone down a 
 long and steep slope. The stone goes gently enough at first, 
 but rapidly gains speed, until at last it makes great bounds 
 from the earth, tearing and crashing through everything as if 
 it had been shot from a cannon. 
 
 I have seen a stone which was too heavy to be lifted, and 
 had to be prised over the edge with levers, spring completely 
 through the topmost branches of a high tree, scattering the 
 boughs in all directions, and then, alighting on another stone, 
 split into many fragments, just like the pieces of a burst shell. 
 That one stone would have swept off a whole party of soldiers 
 had they encountered it while trying to ascend the slope.
 
 ROLLING STOXES. 
 
 137 
 
 THIS invention has also been anticipated in Nature. 
 
 Putting aside the obvious reflection that the most primitive 
 warriors must have noticed the effects of stones falling over 
 a precipice, we have, in Captain Hall's " Life with the 
 Esquimaux," a curious account of the Polar Bear and its mode 
 of killing the Walrus. Gigantic as is this animal, and terrible 
 as are its tusks, the Polar Bear will sometimes attack it in a 
 very singular manner. The Bear springs on a sleeping Walrus, 
 and clings to its shoulders with one paw, and with repeated 
 blows from the other, fractures its skull. 
 
 Still, the combat is sure to be a severe one, and so the Polar 
 Bear will, if he can, secure his prey by some other method. 
 
 " The natives tell many most interesting anecdotes of the 
 Bear, showing that they are accustomed to watch his move- 
 ments closely. He has a very ingenious method of killing the 
 Walrus. 
 
 " In August, every fine day, the Walrus makes its way to 
 the shore, draws its huge body upon the rocks, and basks in 
 the sun. If this happen near the base of a cliff, the ever- 
 watchful Bear takes advantage of the circumstance to attack 
 
 BEAR KILLING WALRUS. 
 
 WARRIORS DEFENDING A PASS. 
 
 his formidable game in this way. The Bear mounts the cliff, 
 and throws down upon the animal's head a large rock, calcu- 
 Ltting the distance and the curve with astonishing accuracy, 
 and thus crushing the thick, bullet-proof skull. 
 
 " If the Walrus is not instantly killed, or simply stunned,
 
 138 
 
 NATURE'S TEACHINGS. 
 
 the Bear rushes down to it, seizes the rock, and hammers away 
 at the head until the skull is broken. A fat feast follows. 
 Unless the Bear is very hungry, it eats only the blubber of the 
 walrus, seal, and whale." 
 
 IMITATION. 
 
 As is the case with the Norwegians, the Esquimaux have 
 the greatest respect for the intellectual as well as the bodily 
 powers of the Bear, and avowedly imitate it in its modes of 
 hunting. One of these methods will now be mentioned. 
 
 It must first be premised that the Seal is a most wary 
 animal, and when it lies down on the shore to sleep, it takes 
 its repose by snatches, lifting up its head at very short inter- 
 vals, looking all round in search of foes, and tht-n composing 
 itself to rest again. To approach so cautious an animal is 
 evidently a difficult task, but the Bear is equal to it. The 
 following is Captain Hall's account : 
 
 " From the Polar Bear the Innuits (i.e. Esquimaux) learn 
 much. 
 
 " The manner of approaching the Seal, which is on the ice 
 by its hole, basking in the sunshine, is from him. The Bear 
 
 POLAR BEAB HUNTING SEAL. 
 
 ESQUIMAUX HUNTING SEAL. 
 
 lies down and crawls by hitches towards the Seal, 'talking' 
 to it, as the Innuits say, until he is within striking distance, 
 when he pounces upon it with a single jump. The natives say 
 that if the}'- could ' talk ' as well as the Bear, they could catch 
 many more Seals. 
 
 " The procedure of the Bear is as follows. 
 
 " He proceeds very cautiously towards the black speck, far 
 off on the ice, which he knows to be a Seal. When still a long
 
 DECOYING THE MOTHER SEAL. 
 
 139 
 
 way from it, he throws himself down and hitches himself along 
 towards his game. The Seal, meanwhile, is taking its naps of 
 about ten seconds each, invariably raising its head and survey- 
 ing the entire horizon before composing itself again to brief 
 slumber. 
 
 " As soon as it raises its head, the Bear ' talks,' keeping per- 
 fectly still. The Seal, if it sees anything, sees but the head, 
 which it takes for that of another Seal. It sleeps again. Again 
 the Bear hitches himself along, and once more the Seal looks 
 around, only to be 'talked' to and again deceived. Thus the 
 pursuit goes on until the Seal is caught, or till it makes its 
 escape, which it seldom does." 
 
 It is remarkable that while this " talk " is going on, the Seal 
 appears to be charmed, raises and shakes its flippers about, rolls 
 over on its side and back, as if delighted, and then lies down to 
 sleep. 
 
 Now, the Esquimaux hunters imitate, as nearly as they can, 
 the proceedings of the Bear, but are not so successful. Captain 
 Hall mentions several instances where the native hunter failed 
 even to come within gunshot without alarming the Seal, which 
 instantly plunged into its hole and \vas lost. 
 
 THE same author mentions another instance where the 
 Esquimaux hunter has copied the Bear. 
 
 When an Esquimaux hunter catches a young Seal, he takes 
 
 care not to kill it at once, as he wishes to use it as a decoy. He 
 ties a long line round one of the hind flippers, and then drops 
 the little Seal into the hole through the ice by which it enters 
 and leaves the water. The struggles of the young are nearly sure
 
 140 NATURE'S TEACHINGS. 
 
 to attract the mother, and when she has discovered its con- 
 dition the young Seal is cautiously drawn up on the ice. The 
 mother follows, too intent on rescuing her young to think 
 about herself, and, as soon as she is within reach, she is struck 
 with the harpoon. 
 
 The Polar Bear, however, preceded the Esquimaux in this 
 mode of hunting. The young Seal lives in a hemispherical 
 dwelling scooped out of the snow, and communicating with the 
 water by means of a hole through the ice. This dwelling will 
 be described and figured when we come to the subject of 
 Architecture. 
 
 Finding out, by scent or some other means, the habitation 
 of the young Seal, the Polar Bear leaps upon the snow, bring- 
 ing his feet together, and with his enormous weight breaking 
 through the roof of the dwelling. He instantly captures the 
 young Seal before it can make its escape. Then, driving the 
 talons of one paw into its hind flipper, he lets it into the hole, 
 and allows it to flounder about in the water. When the mother 
 is attracted to her young, he draws his prey slowly up on the 
 ice. The anxious mother follows, and is at once secured by the 
 talons of the other foot, as is represented in the illustration. 
 
 THE FALL-TRAP. 
 
 THIS is a stratagem which is often employed in "War and 
 Hunting, though its use is mostly confined to the latter. 
 Schoolboys often avail themselves of this principle when they 
 wish to play a practical joke, and to amuse themselves by 
 setting a " Booby-trap." This trap is easily manufactured, and 
 consists of a partially opened door, with a basin or jug of water 
 balanced upon it. The natural result is, that any one who 
 opens the door without proper precautions receives the jug and 
 its contents upon his head, and is thoroughly drenched. 
 
 On the right hand of the illustration is seen a curious spear, 
 the butt of which, instead of being lighter than the head, is 
 very much heavier. The weight, however, is exactly where it 
 is wanted, and indeed, in actual use, is trebled by a mass of 
 tenacious clay, kneaded upon it. This figure is taken from a 
 very perfect specimen in my own collection. 
 
 It is an African weapon, not used for war, but for hunting,
 
 THE FALL-TRAP. 
 
 141 
 
 and, as far as I know, exclusively employed against the ele- 
 phants. These animals have a way of forming roads or tracks 
 for themselves through the woods, very much like those almost 
 invisible paths which are made by the half-wild sheep of the 
 great Wiltshire Downs, except that they traverse thick forests 
 instead of broad downs. 
 
 The native hunters know all the elephant paths, and if a 
 herd of elephants be seen approaching, the path which they will 
 take is tolerably certain. 
 
 Armed with this knowledge, the native hunters climb the 
 trees, and seat themselves on the branches which overhang 
 the path, each hunter being supplied with one of these spears. 
 As the elephants pass beneath him, the experienced hunter 
 
 MANGBOVE SEEDS. 
 
 HIPPOPOTAMUS TRAP AND ELEPHANT 
 SPKAR. 
 
 selects a bull elephant with good tusks, and, taking a careful 
 aim, drops the spear on its back. 
 
 On receiving the stroke, the elephant rushes off in mixed 
 terror and rage. As the animal uses the legs of each side 
 alternately, it sways its huge body from side to side at every 
 step. With each movement, the spear also sways about, its 
 weighted end giving it such a leverage, that the sharp edges of 
 the head cut the poor animal to pieces. 
 
 ANOTHER kind of Fall-trap, which is common in many parts 
 of Southern Africa, is not dependent upon the skill of the 
 hunter, but, like the "booby-trap" above mentioned, is set in 
 motion by the victim.
 
 142 NATURE'S TEACHINGS. 
 
 A figure of this trap is given in the illustration. 
 
 If the native hunter can find a spot where the Hippopotamus 
 path passes under an overhanging branch, he makes a simple 
 but most effective trap. He takes a heavy log of wood, and 
 into one end of it he drives a spear-point. The log is then hung 
 with its point downwards to the branch, the rope which is con- 
 nected with its trigger or catch being stretched across the 
 path at a few inches from the surface of the ground, and 
 carried at right angles across the path. 
 
 The Hippopotamus takes no notice of the cord, which is 
 usually made of one of the creepers or " bush-ropes " that are 
 so common in hot countries. No sooner, however, does its foot 
 strike the cord, than the trigger is released, and down falls the 
 heavy log, driving its iron point deeply into the back of the 
 victim. Even if the weapon were simple iron, such a wound 
 must be mortal, but, as it is almost invariably poisoned, the 
 wounded animal can scarcely travel forty or fifty yards before 
 it lies down and dies. 
 
 One of these traps is shown in the illustration. In the fore- 
 ground is shown the Fall-trap, pointed with iron, and weighted 
 with large stones at the lower end, so as to bring it down with 
 more force, and to prevent it from falling transversely. 
 
 The Spring-gun, once so formidable a protector of our 
 coverts, was managed in a similar manner, except that the 
 missile was discharged horizontally, and not vertically. The 
 gun, loaded with shot, was fixed some eighteen inches from the 
 ground, and a long and slight wire fastened to the trigger. 
 The opposite end of the wire was made fast to a tree or other 
 fixed object, and, as the gun was directed on the line of the 
 wire, it is evident that any one who stumbled against it would 
 discharge the gun, and receive the contents in his legs. 
 
 In France the gun was generally loaded with little pieces of 
 bay salt, and I very much pity the unfortunate poacher who 
 came across one of these guns. The pain would prevent him 
 from escaping, and I think that the hardest-hearted of game 
 preservers could not bring himself to prosecute a man who had 
 already suffered so much. 
 
 Of a similar character are the Spring-bows which were once 
 common in this country, and are still used in various parts of 
 Asia. A bow and arrow are substituted for firearms, and the
 
 THE MANGROVE-TREE. 143 
 
 bow, after being drawn by the united efforts of several men, is 
 held in its position by a stick, one end of which presses against 
 the centre of the bow, and the other against the string. 
 
 A large arrow is then placed on the bow, and a cord is tied 
 to the middle of the stick, led forwards in a line with the 
 direction of the arrow, and fastened, as in the case of the spring- 
 gun. As soon as the line is struck, the stick is jerked from its 
 place, and the arrow is discharged, piercing the body of the 
 trespasser. Tigers, bears, and leopards are the usual victims of 
 this trap. 
 
 IT is remarkable that in the same country there is a pro- 
 duction of Nature which may in all probability have given to 
 the native hunter the idea of the Fall-trap. This is the Man- 
 grove-tree, which is remarkable for the wonderful extent of 
 ground which it will cover, and the nearly impenetrable 
 thickets which it forms. In the present part of the work we 
 have nothing to do with the aerial roots, several of which are 
 shown in the illustration, and only restrict ourselves to the 
 Seeds, and the curious manner in which they are planted by 
 Nature. 
 
 In the illustration, on the left hand, the growth of the 
 Mangrove is seen. The drawing is taken from a sketch by 
 the late Mr. Baines, and generously placed at my disposal, as 
 were all his drawings and journals. 
 
 The Mangrove is a wet-loving tree, never flourishing unless 
 rooted in mud ; and whether the moisture of the mud be 
 attributable to fresh or salt water seems to make little dif- 
 ference to the Mangrove, which, of the two, appears to prefer 
 the latter. Now, the seeds of the Mangrove look very much 
 like elongated skittles, except that one end comes to a sharp 
 point. As they hang on the tree, the point is downwards. 
 When they are ripe, they fall from the branch, and by their 
 own weight are driven deeply into the mud, where they 
 develop roots and leaves, and become the progenitors of the 
 future Mangrove race. 
 
 I cannot but think that the native hunter, having seen the 
 tremendous force with which the Mangrove seed buries itself 
 in the mud, has applied the same principle to a weapon which 
 shall bury itself in the body of an elephant.
 
 WAR AND HUNTING. 
 
 CHAPTER VIII. 
 
 CONCEALMENT. DISGUISE. THE TRENCH. POWER OF 
 GRAVITY. MISCELLANEA. 
 
 Concealment needed in Modern Warfare. Concealment by Covering. Masking 
 Guns. Birnam Wood. The Reduvius. The Cuckoo-spit and the Spider- 
 crab. Concealment by Disguise. Stratagem of the Barea. Complete 
 Deception. Larva of Geometra. The Leaf-insect. The L-tppet-moth. 
 The Ptarmigan and the Ermine. Principle of the Trench. The Hunter's 
 "Skarm." The Wax-moth or Galleria-moth, and its Tunnel. Fate of a 
 Collection. The Termites and the Travelling Ants of South America. The 
 Power of .Gravity. The Battering-ram and its Force. Miscellanea. War 
 by Suffocation. The Stink-pot. The Chili-plant. The Sulphur-room. 
 The Botnbadier-beetle. The Bullet-making Machine and the Silkworm. 
 
 CONCEALMENT. 
 
 WE will first take Concealment by means of Covering. 
 If History repeats herself, so does Warfare. I have 
 already shown the repetition of History in the Fortress I 
 shall now show it in the Field. 
 
 In former days, when arms of precision were not invented, 
 concealment was not needed. No soldier ever was visited with 
 a dream so wild as that of taking definite aim at the enemy, 
 and reserving the fire until the aim was certain. I have in my 
 collection several of the French and English muskets used 
 about the time of Waterloo, and, though a fair rifle-shot, 
 would not engage to hit a haystack with either of them at a 
 distance of a hundred yards. With the Snider or Martini- 
 Henry in the hands of a skilful adversary, he would be a bold 
 man who would offer himself for a target at a thousand yards. 
 Indeed, if the first shot happened to miss, the marksman
 
 CONCEALMENT IN WARFARE. 
 
 145 
 
 would be tolerably sure to notice tlie failure, and to correct his 
 aim with fatal certainty. 
 
 In those days, therefore, concealment was rather ridiculed 
 than praised, the power of the new arm not being as yet appre- 
 ciated. I well recollect, in the earliest days of the Volunteer 
 movement, hearing a Volunteer captain declare, amid the 
 cheers of his company, that " he had never sneaked behind a 
 tree in all his life, and was not going to begin now." 
 
 In the present day, the power of the missile has been 
 developed with such astounding rapidity, that to be exposed 
 to the fire of rifles or cannon is almost certain death. Indeed, 
 the only safety of the defence lay in the fact that the smoke 
 soon rendered very accurate shooting impossible at long ranges, 
 and that at short ranges, if a man got a bullet through his 
 body, it mattered little to him whether the missile were a 
 spherical musket-ball or a conical rifle-bullet. 
 
 Just, then, as forts have latterly sunk into the earth for the 
 purpose of strength, so have our modern soldiers found that 
 the true principle of modern warfare is never to lose sight of 
 
 BEDUVIUS (MAGNIFIED). 
 
 CUCKOO-SPIT. 
 
 SPIDER-CRAB. 
 
 MASKING GrxB. 
 BIKXAM WOOD. 
 
 the enemy, and never to allow the enemy to see yourself or 
 the disposal of your troops.
 
 146 NATURE'S TEACHINGS. 
 
 Everything must be revealed to the commander-in- chief, 
 everything must be concealed from the enemy. 
 
 In the late Franco-German war the principle of conceal- 
 ment was largely used, and when cannon were brought into 
 the field by the Germans for the purpose of attacking fortresses, 
 they were always hidden under branches of trees, so that the 
 enemy should not distinguish them from the ordinary features 
 of the country, and that the sparkle of the sunbeams upon 
 them might not be seen. 
 
 It would be almost superfluous to remind the reader of 
 Malcolm's stratagem when besieging Dunsinane Castle : 
 
 " Let every soldier hew him down a bough, 
 And bear 't before him ; thereby shall we shadow 
 The numbers of our host, and make discovery 
 Err in report of us." 
 
 Precisely similar modes of concealment are to be found in 
 the animal world. 
 
 There is a certain insect belonging to the Heteroptera, and 
 scientifically named Reduvius personatus. I am not aware 
 whether it has any popular name. It is insectivorous, and 
 ought to be welcomed in houses, as it is particularly fond of 
 the too common bed-bug. So carnivorous are these insects 
 that one of the Reduviidse killed and sucked a companion of 
 her own sex, her own mate, and, after only a few days' fast, 
 her own young, and then sucked her own eggs. 
 
 During its larval and pupal stages of existence, the Reduvius 
 covers its body and limbs with dust and any other refuse which 
 it can find. In this manner it disguises its form so completely 
 that it scarcely looks like an insect. Occasionally it seems to 
 be dissatisfied with its coat of dust, throws it off, and sets to 
 work at a new one. 
 
 One of these creatures, as it appears when covered with its 
 dusty coating, is seen in the upper left-hand corner of the 
 illustration. It is slightly magnified. 
 
 Below the Reduvius is the common Cuckoo-spit (Aphrophora 
 spumaria), whose frothy masses are so plentiful in our hedge- 
 rows and gardens. 
 
 If one of these masses be carefully opened, there will be 
 found in it a little green creature with small, round, dot-like 
 eyes. This is either the larval or pupal state of the Frog-
 
 THE BAREA STRATAGEM. 147 
 
 hopper, as the insect is called in its perfect state, from its 
 habit of taking long and sudden leaps when alarmed. 
 
 I well remember my delight when, as a child, I set to work 
 at examining these froth-masses, and succeeded in tracing the 
 insect through all its changes. The froth is derived from the 
 sap of the tree, which is sucked through the proboscis, passed 
 through the digestive organs, and then ejected in a succession 
 of little bubbles. After awhile a little drop of clear liquid is 
 seen to collect at the bottom of the froth, to increase, and then 
 to fall, when another immediately begins to be formed. One 
 species of Cuckoo- spit, which inhabits Madagascar, acts almost 
 like a siphon on the tree, and pours out large quantities of 
 clear water during the hottest part of the day. 
 
 Within this froth-mass the insect lies concealed, and, 
 though utterly helpless, is safe from most of the enemies that 
 would attack it if it were left exposed. 
 
 Beneath the Cuckoo-spit is the common Spider-crab, some- 
 times called the Thornback-crab, from the numerous spines with 
 which its body is covered. Its scientific name is Maia squinado. 
 
 When the Spider-crab attains to a tolerable size, its rough 
 surface forms attachment for various marine beings, chiefly 
 those belonging to the zoophytes. In some cases these 
 zoophytes grow to such a size that the Crab is completely 
 covered by them, and its original shape effectually concealed. 
 When one of these creatures is seen in a living state it pre- 
 sents the curious spectacle of a large bunch of zoophytes and 
 corallines moving about from place to place without any per- 
 ceptible limbs, the whole of the surface of the Crab being 
 covered with extraneous growths. 
 
 DISGUISE. 
 
 NEXT comes concealment by means of Disguise. 
 
 On the right hand of the accompanying illustration is shown 
 a singular mode of concealment adopted by the Barea, a 
 warlike and predatorial tribe of Abyssinia. When Mr. Mans- 
 field Parkyns was resident in Abyssinia he fell in with the 
 Barea, through whose country he had to pass. 
 
 " Scarcely had we passed the brook of Mai-Chena when one 
 of our men, a hunter, declared that he saw the slaves. Being 
 at that time inexperienced in such matters, I could see nothing 
 
 L2
 
 148 
 
 NATURE S TEACHINGS. 
 
 suspicious. He then pointed out to me a dead tree standing 
 on an eminence at a distance of several hundred yards, and 
 charred black by last year's fire." Here I must explain that 
 in Abyssinia, as in several other parts of the world, the ground 
 is annually, cleared of its superabundant vegetation by setting 
 fire to it, and allowing the flames to burn themselves out. 
 
 " However, all I saw was a charred stump of a tree and a 
 few blackened logs or stones lying at its feet. The hunter 
 declared that neither the tree nor the stones were there the last 
 
 LEAF-INSECT. 
 PTARMIGAN. 
 
 CATERPILLAR OP 
 
 OEOMETBA. 
 LAPPET-MOTH. 
 
 BAREA STRATAGEM. 
 
 time we passed, and that they were simply naked Barea, who 
 had placed themselves in that position to observe us, having 
 no doubt seen us for some time, and prepared themselves. 
 
 " I could scarcely believe it possible they could be so motion- 
 less, and determined to explore a little. The rest of the party 
 advised me to continue quietly in the road, as it was possible 
 that, from our presenting a rather formidable appearance, we 
 should pass unmolested ; but so confident was I of his mistake, 
 that, telling the rest to go on slowly as if nothing had been 
 observed, I dropped into the long grass and stalked up towards 
 them. 
 
 " A shot from my rifle at a long distance (I did not venture 
 too close) acted on the trees and stones as powerfully as the 
 fiddle of Orpheus, but with the contrary effect ; for the tree
 
 LOOTERS, LEAF-INSECT, AND LAPPET-MOTH. 149 
 
 disappeared, and the stones and logs, instead of running after 
 me, ran in the opposite direction. 
 
 " I never was more astonished in my life, for so complete 
 was the deception that even up to the time I fired I could have 
 declared the objects before me were vegetable or mineral 
 anything, indeed, but animal. The fact was that the cunning 
 rascals who represented stones were lying flat, with their little 
 round shields placed before them as screens." 
 
 This stratagem is shown on the right hand of the illustration. 
 
 ON the left are a few of the innumerable instances in Nature 
 where Concealment is obtained by imitation. 
 
 The three examples which are here given are familiar to all 
 entomologists. 
 
 The upper figure represents two of the Geometra or Looper 
 Caterpillars, as they appear when at rest, and affixed to a twig. 
 This appears to be a singular attitude of rest, but it is one 
 in which they delight, and in which they remain for hours 
 together, the claspers at the end of the body tightly grasping 
 the branch, and the whole body held out so straight and 
 motionless that it is hardly possible to believe that a veritable 
 twig is not before the eye. The colour is that of the twig, 
 and the different segments of the body look exactly like the 
 little irregularities and projections of a young twig. 
 
 I have more than once seen a novice in entomology unable 
 to distinguish these larvee, even when the branch was pointed 
 out, and there were several upon it. 
 
 Just below the Loopers, and on the left hand of the illus- 
 tration, is shown the well-known Leaf-insect (Phy Ilium). 
 These strange beings have the elytra and the flattened 
 appendages of the legs so exactly like leaves that the most 
 experienced eye can scarcely distinguish them from the leaves 
 among which they are placed. Even when they have been on 
 a small plant, such as a myrtle in a flower-pot, I have had the 
 greatest difficulty in finding them, and have seen people examine 
 the plant, and then go away declaring that no insects were on it. 
 
 On the right hand, and just below the looper caterpillar, is 
 the common Lappet-moth of this country, shown in its position 
 of rest. 
 
 When it assumes this attitude, it looks exactly like a withered
 
 150 NATURE'S TEACHINGS. 
 
 leaf, the resemblance extending not only to the form, but the 
 colour. All entomologists are familiar with many similar 
 examples in insect life. The common Tortoise-shell Butterfly, 
 for example, has a way of settling on patches of red soil, with 
 which it harmonizes so well that it can hardly be seen. The 
 various moths, also, are in the habit of resting on tree-bark, 
 palings, and other objects, to which they instinctively know 
 that they assimilate in hue. Many a beginner in entomology 
 will pass a wooden fence or a wall, and not see an insect on 
 either, while an adept will follow him and take twenty or 
 thirty good specimens. 
 
 The last figure in the illustration represents a Ptarmigan 
 (Lagopus vulgaris) in its winter dress. These birds have two 
 differently coloured dresses, one for summer and the other for 
 winter, and both adapted for concealment by imitation. In 
 the former dress it is mottled with various shades of blackish 
 brown, yellow, and white. As the bird is in the habit of 
 settling among the grey lichen-covered stones on the sides of 
 rocky hills, these colours harmonize so exactly with them that 
 a Ptarmigan may almost be trodden upon before it is perceived. 
 
 In the winter, when the snow covers the whole country with 
 one uniform sheet of white, except where the wind blows the 
 snow aside, and exposes the underlying stones, the Ptarmigan 
 assumes a different plumage, being almost entirely white, 
 except a black streak over the eye, and the outer feathers of 
 the tail, which are also black. Thus the bird becomes almost 
 indistinguishable from a snow-covered stone, especially as it has 
 a habit of squatting motionless and silent when it takes alarm. 
 
 The reader may, perhaps, remember that the common Stoat 
 also has a summer and winter dress. The ordinary colour is 
 rich reddish brown above, and white beneath, with a black tip 
 to the tail. In the severe winters of Northern Europe the 
 Stoat exchanges his ruddy coat for one of pure white, and is 
 then known by the name of Ermine. It is remarkable that in 
 the winter dress both of the Ptarmigan and Stoat the tail is 
 black, while the rest of the coat is white. 
 
 THE TRENCH. 
 
 WE now come to a third mode of concealment in war, 
 namely, that which is obtained by means of Trenches or Pits.
 
 THE TRENCH. 151 
 
 Even in hunting the pit or partial trench is largely used. 
 In Southern Africa the hunter often employs such a trench, 
 called technically a " Skarm." It is very simple in idea, 
 and easily made, being based on the principle that lions, 
 elephants, &c., look for their assailants on the level of the 
 earth, and seldom, if ever, look above or below it. Accord- 
 ingly the hunter, having marked some pool or lake whereunto 
 the wild animals resort at night to quench their thirst, chooses 
 a convenient spot, and there digs a trench some seven feet in 
 length and four deep, and covers it in with stout tree-branches 
 and logs of various size. The whole is roofed in with sods, 
 and the only entrance is at one end. 
 
 Here the hunter sits and waits, and, as his ear is on a level 
 with the surface of the ground, he can hear at a considerable 
 distance sounds which would have escaped him had he been erect. 
 
 Waiting for a favourable opportunity, as the various beasts 
 come to drink, the hunter chooses one, takes careful aim, and 
 fires one of his heaviest guns. It is but seldom that the rest 
 of the animals charge in the direction of the Skarm, but even 
 
 GALLERIA-MOTII (liAEVA). KILITAET TBESCH. 
 
 if they do, the hunter is quite safe under the shelter of his 
 strong roof, which is able to resist even the heavy tread of an 
 elephant. 
 
 In modern warfare, and especially during sieges, the trench 
 is largely used, and is constructed on the most scientific prin- 
 ciples, so as to shelter the assailants, while enabling them to 
 proceed nearer and nearer to the fortress. A portion of one of 
 these trenches is shown in the right hand of the illustration. 
 
 ON the opposite side of the same illustration is shown the 
 same principle as carried out in Nature. 
 
 There is a certain little insect, called the "Wax-moth, or 
 Galleria-moth (Galleria akearia), which, although quite
 
 152 NATURE'S TEACHINGS. 
 
 harmless in its perfect form, is in its larval state extremely 
 injurious to beehives. 
 
 The mother moth contrives, aided by her tiny form and 
 sombre colouring, to slip past the sentries at the mouth of the 
 hive, and to lay her eggs among the combs. This done, she 
 dies, but the evil of her visit lives after her. 
 
 Each of the eggs is hatched into a little caterpillar, having a 
 soft grey body, but a hard, horny head of a black-brown colour. 
 As soon as they are hatched they begin to feed, eating not only 
 the waxen combs, but the honey and the bee-bread which were 
 intended for the support of the legitimate inhabitants. 
 
 The reader may ask why the bees do not destroy this 
 marauder on their premises. They would be only too glad to 
 do so, but they cannot touch it. As it eats its way along, it 
 constructs a strong silken tube, within which it lives, and 
 which it gradually lengthens. This tube or gallery is exceed- 
 ingly tough, and perfectly capable of resisting the bee's sting. 
 Moreover, the caterpillar traverses its tube with such rapidity 
 that the bee has no chance of knowing whereabouts the cater- 
 pillar may be when it makes its attack. "When it feeds it only 
 protrudes its armed head, the horny covering of which is an 
 effectual protection against the sting. 
 
 When these creatures fairly get hold of a hive, the damage 
 which they do is terrible, the whole of the combs being 
 enveloped in the ever-increasing labyrinth of tubes. Even 
 the bees themselves fall victims to the Galleria-moth, for the 
 silken tunnels are driven through and through the combs, 
 enveloping the broad cells as in the meshes of a net. Conse- 
 quently, when the young bees are developed, they cannot escape 
 from their cells, and perish miserably. 
 
 Nor do these tiresome insects confine themselves to hives; but 
 they have an extraordinary facility for discovering bee-combs 
 after they are removed from the hive. Some years ago I was 
 making a collection of various insect habitations, and had 
 brought together a carefully selected set of combs, showing the 
 internal structure of the hive, and the different cells which are 
 inhabited by the worker, the drone, and the queen bee. 
 
 One day, when about to arrange the collection in a glass 
 case, I found that the whole of the combs had been destroyed 
 by the Wax-moth. Scarcely a square inch of comb remained,
 
 THE BATTERING-RAM. 153 
 
 and the contents of the box were little more than a congeries 
 of Wax-moth galleries. Even the "Wasp and Hornet nests 
 which had been placed in the same box had been attacked, and, 
 although they had not been so utterly destroyed as the waxen 
 cells, they had been sufficiently injured to render them unfit 
 for exhibition. 
 
 Many other insects work on the same principle. Certain 
 Termites, for example, construct tunnels of clay, in order to 
 conceal them on their travels, and have the art, even in the 
 hottest and driest weather, of mixing their clay with some 
 liquid which renders it, when dry, nearly as hard as stone. 
 Indeed, there have been instances where the Termites have 
 attacked the wooden beams of houses, and literally transformed 
 them into beams of stone. 
 
 Then there are many Ants, notably several species of South 
 America, which cover their approach by tunnels, and never 
 venture into the open air. 
 
 GRAVITY AS A PROPULSIVE AGENT. 
 
 THE two figures on the accompanying illustration will almost 
 speak for themselves. 
 
 "We have already seen how the same force of gravitation 
 which causes the avalanche to thunder down the precipice may 
 be utilised as a means of projecting missiles in time of war. 
 When, however, the stones or beams were once sent on their 
 destructive mission, they were out of the control of those who 
 
 BAH. BEAD OF BATTERIXG-RAM. 
 
 launched them. We now come to a modification of the force 
 of Gravity, by which the missile, if we may so term it, is kept 
 undsr control, its power increased or diminished at will, and its 
 point of attack shifted according to the requirements of the 
 moment. 
 
 Before the invention of artillery, the Battering-ram was by 
 far the most formidable engine that could be brought against 
 a fortified place. The principle of the Battering-ram was
 
 154 NATURE'S TEACHINGS. 
 
 simple enough. A long and heavy beam, generally the trunk 
 of a tree, was suspended by ropes at the centre of gravity, so 
 that it could be swung backwards and forwards. Although a 
 simple beam was an effective weapon, its value was much 
 enhanced by loading the thickest end with a heavy mass of 
 metal, usually iron, and, when there was time for adorn- 
 ment, roughly modelled into the form of a ram's head. 
 
 Generally the Battering-ram was mounted on an elevated 
 platform, and the soldiers who worked it protected by a roof, 
 which was called by the name of Testudo, or Tortoise. The 
 force of this weapon was tremendous, and no wall, however 
 strong, could resist it. Sometimes the beam was considerably 
 more than a hundred feet in length, being composed of several 
 pieces bolted and banded together with iron. 
 
 It may easily be imagined that such a weapon as this must 
 have been a most terrible one, and, indeed, the whole success 
 of the siege practically depended upon it. The assailants did 
 their best to bring the Battering-ram into position under the 
 walls, and the besieged did their best either to keep it away, 
 or to neutralise its effects by catching it with nooses, dropping 
 large stones upon it so as to break or dismount it, or, if they 
 could not succeed in either of these attempts, they deadened 
 the force of its blows as well as they could by interposing 
 large sacks of wool between the wall and the head of the ram. 
 
 Considering the style of architecture which was then used 
 in fortification, namely, a combination of height with thickness, 
 the force of the Battering-ram would be even greater than 
 that of artillery. The regular and rhythmical swing of the 
 ram would soon communicate a vibratory motion to the wall, 
 which would of itself tend to disintegrate the whole structure, 
 while the blows of the iron head beneath broke away the 
 stones, and rendered the downfall of the fort a mere matter of 
 time. 
 
 The reader need hardly be reminded that the Battering-ram 
 was so called because its mode of attack was practically the 
 same as that of the animal from which it took its title. 
 
 MISCELLANEA. 
 
 BY slow degrees, mankind, as they advance in civilisation, 
 have robbed warfare of many horrors. Non-combatants, for
 
 SUFFOCATION AS A WEAPON. 155 
 
 example, are now left unharmed. Poisoned weapons have, by 
 common consent, been abolished, and so have those instruments 
 of warfare which, though they do not simply poison the blood 
 by means of bodily wounds, do so by means of noxious vapours 
 poured into the lungs. 
 
 It is sometimes rather unfortunate when civilisation and 
 semi-barbarism meet in battle ; the former respecting the cus- 
 toms of honourable warfare, and the latter ignoring them. 
 For example, in olden times, one of the most potent weapons in 
 naval combat was the " stink-pot " i.e. a vessel filled with 
 sulphur and other ingredients, and emitting a smoke which was 
 death when inhaled. Among the American Indians the well- 
 known Chili-plant was much used for this purpose, the very 
 first breath that was taken of the thin and almost invisible 
 smoke causing the throat to contract as if clutched by a strong 
 
 BOMBAUD1KK-BKKTLE. CHINESE STINK-POTS. 
 
 hand. If then any enemies had taken refuge in a cave, or 
 were suspected of having done so, a fire was lighted at the 
 entrance, a quantity of chilis thrown on it, and the rest left to 
 time. No being could endure that smoke and live, and they 
 must either stay in the cave and die, or come out and deliver 
 themselves up to their foes. The former was the better part 
 to take, as suffocation, however slow, is only an affair of a few 
 minutes, while death by torture is prolonged through hours. 
 
 In the late Chinese war the stink-pot was extensively used, 
 and our sailors took it in very bad part that the enemy should 
 be allowed to employ such weapons, and they should be debarred 
 from using them. 
 
 "Whether this principle is still retained in the defence of 
 fortresses I do not know. I recollect, however, some twenty 
 years ago, going over a fortress in which suffocation was em- 
 ployed as a means of defence. A long gallery was so placed 
 that the assailants were tolerably sure to force their way into 
 it, thinking that it led to the interior of the fort.
 
 156 NATURE'S TEACHINGS. 
 
 It was, however, nothing but a trap, for it had no exit. As 
 soon as a number of the assailants had poured into this trap, 
 their exit was suddenly cut off by machinery provided for the 
 purpose, and at the same time a quantity of sulphur and lighted 
 charcoal was shot into the gallery from above, and the aperture 
 instantly closed. It would be absolutely impossible that any 
 one who had been enclosed in that terrible chamber should 
 escape with life, for the first breath of that deadly vapour would 
 render the strongest man insensible. 
 
 NATURE, as usual, has anticipated Art even in this par- 
 ticular. 
 
 In several parts of England, and especially along the shores 
 of the Thames towards Gravesend, a little beetle is to be found 
 under the flat stones of the river bank. Its scientific name is 
 Brachinus crepitans. When this insect is alarmed, it has the 
 power of ejecting a peculiar liquid, which, when it comes in 
 contact with the atmosphere, bursts into a sort of pale blue- 
 green flame, followed by a kind of smoke. Sometimes, when a 
 tolerably large stone is lifted, the little explosions will go 
 popping about in a most curious manner. Indeed, they carry 
 reminiscences of school days, when it was a joy to distribute 
 single grains of coarse gunpowder on the bars of the grate, 
 and watch them melt, take fire, explode, and send forth little 
 clouds of smoke. The insect is popularly called the Bombar- 
 dier-beetle. Whether or not this capability be given as a 
 means of defence I cannot say, but it assuredly answers that 
 purpose. 
 
 There are several of the voracious Carabidae, or Ground- 
 beetles, which would be very glad to make a meal of the 
 Brachinus. When, however, the Bombardier-beetle finds itself 
 on the point of being overtaken, it elevates the abdomen with 
 a peculiar gesture, and ejects the liquid. The effect on the 
 pursuer is remarkable. It seems overwhelmed and stupefied 
 by the sudden attack, moves about for awhile as if blinded, 
 and, by the time that it has recovered its sense, the Bombardier- 
 beetle is out of sight. 
 
 In some of the hotter parts of the world there are several 
 species of Bombardier-beetles which attain considerable size, 
 and their discharge is powerful enough to discolour the skin of 
 the human hand.
 
 BULLET-MAKING MACHINE. 
 
 157 
 
 I HAVE felt some little difficulty in classifying the curious 
 invention which will now be described, but, as it is used for the 
 purpose of making bullets, I have placed it in the category of 
 War. 
 
 In the days of " Brown Bess," as the old musket used to be 
 called, precision of aim was not required, for no commander 
 
 B 8 
 
 SILK APPARATUS OF SILKWORM. 
 
 BULLET-MAKING APPARATUS. 
 
 dreamt of opening fire until the enemy were at comparatively 
 close quarters. In those days the bullets were spherical, and 
 cast in moulds. After a time, when the Enfield rifle displaced 
 the musket, and did double the execution at three times its 
 range, bullets were still cast, though their shape was altered, 
 and they took a sugar-loaf form instead of being spherical. 
 
 The rifle -testing machine at Woolwich, however, soon 
 showed that at long ranges a cast bullet was nearly useless, one 
 part being always lighter than another, and air-bubbles often 
 taking the place of lead. After being cast, therefore, the 
 bullets were placed in a " swedge," or " swage," i.e. a machine 
 by which the lead was forcibly compressed until it was of a 
 tolerably uniform density. Even this process, however, did 
 not insure absolute exactness, and then a machine was invented 
 by means of which the process of casting was superseded, and 
 the bullets were pinched or squeezed, so to speak, out of cold 
 lead. 
 
 On the right hand of the illustration is a plan of the inge- 
 nious apparatus by which the lead is supplied to the machine 
 which actually forms the bullets. The sketch is not meant as 
 a drawing of the actual machine, but is merely intended to 
 show the principle.
 
 158 NATURE'S TEACHINGS. 
 
 The chief parts in this machine are a hollow cylinder, a 
 piston, and a delivery tube. The cylinder is shown at A, and 
 when used, is filled with melted lead. The piston, B, is then 
 forced upwards by hydraulic pressure, driving the lead through 
 the delivery tube. As it issues into the air it hardens, and 
 thus forms a solid rod of lead, c. This rod is then passed into 
 the next machine, where it is cut into regular lengths, and 
 these pieces are then placed in moulds, and forced into form 
 by enormous pressure. Were it not for this ingenious 
 machinery, the wonderful scores which are now made at long 
 distances would be impossible. 
 
 Now let us compare Art with Nature, as seen on the left 
 hand of the illustration, which is a chart or plan of the spinning 
 apparatus of the Silkworm. 
 
 When I first saw the bullet-making machine at work, I at 
 once perceived that it was nothing more than a repetition in 
 metal of the beautiful mechanism which I had so often admired 
 in this insect. In order to show the close analogies of the two 
 objects, I have marked them with similar letters. 
 
 A represents the upper part of the reservoir or vessel which 
 contains the silk in a liquid state. B B are the muscles which 
 contract the reservoir and force the liquid matter out. It will 
 be seen that both these vessels terminate in a delivery tube, 
 identical in office with that of the bullet-making machine. As 
 soon as the liquid silk passes into the air it is hardened, and 
 is formed into a silken rod, c, just as is the lead in the machine. 
 The only difference between the two, if it can be called a 
 difference, is, that in the silkworm the rod is double, whereas in 
 the machine it is single. The principle, however, is identical 
 in both cases. The webs of spiders, and the threads by which so 
 many caterpillars suspend themselves, and with which they 
 make their nests, are all formed on the same design, namely, 
 a reservoir containing a liquid which is squeezed through a 
 tube, and hardens when it comes in contact with the air.
 
 AECHITECTUEE. 
 
 CHAPTER I. 
 
 THE HUT, TROPIC AND POLAR PILLARS AND FLOORING. 
 TUNNEL ENTRANCE OF THE IGLOO. DOORS AND HINGES. 
 SELF-CLOSING TRAP-DOORS. 
 
 Primitive Architecture evidently borrowed from the Lower Animals. Roof Hut 
 of the Nshiego Mbouve of Western Africa. Platform Hut of the Orang- 
 outan of Borneo. Lake Dwellers and their Huts. Tree-huts of Southern 
 Africa, and their Uses. Ascendancy of the Wild Beast over Man. Snow- 
 hut of the Seal copied by Esquimaux, and its Value shown. Pillars and 
 Flooring. Crypt and Cathedral. The Cuttle " Bone" and its many-pillared 
 Structure. The Wasp-nest, its Pillars and Floors. Tunnel Entrances to 
 Igloo. Sudden Formation of Snow. Nest of the Fairy Martin. The Sand- 
 wasp and its Mode of Building. Doors and Hinges. Eggs of the Gnat and 
 Rotifer. Cocoons of Ichneumon-flies. Habitations of Microgaster. 
 Trap-doors in Nature and Art. Habitation of the Trap-door Spider. A 
 Nest upon a Pillar. 
 
 THE HUT. 
 
 THERE can be little doubt that mankind has borrowed from 
 the lower animals the first idea of a dwelling, and it is 
 equally true, as we shall presently see, that not only primitive 
 ideas of Architecture are to be found in Nature, but that many, 
 if not all, modern refinements have been anticipated. 
 
 To begin at the beginning. The first idea of a habitation 
 is evidently a mere shelter or roof that will keep off rain 
 from the inhabitant. When Mr. Bowdich was travelling in 
 Western Africa, he was told that the Njina another name 
 for the Gorilla made huts for itself from branches, the natives 
 also saying that it defended these huts with extemporised 
 spears. A more truthful account is given of the Mpongwe 
 and Shekiani, namely, that the animal builds a hut, but lives 
 on the roof, and not under it. 
 
 Although this information has since proved to be false, there
 
 160 
 
 NATURE S TEACHINGS. 
 
 was a foundation of truth in it, for there really is an ape in 
 that part of Africa which makes huts, or rather roofs, for 
 itself. This animal is the Nshiego Mbouve (Troglodytes calmis]. 
 
 This remarkable ape has a curious way of constructing a 
 habitation. Choosing a horizontal branch at some distance 
 from the ground for its resting-place, the animal erects above 
 it a roof composed of fresh branches, each laid over the other 
 in such a way that rain would shoot off them as it does from 
 a thatched roof. M. du Chaillu gives the following account of 
 this habitation : 
 
 " As we were not in haste, I bade my men cut down the 
 trees which contained the nests of these apes. I found them 
 made precisely as I have before described, and as I have always 
 
 NEST OP NSHIEGO 
 
 AFRICAN TREE-HUT. 
 
 found them, of long branches and leaves laid one over the 
 other very carefully and thickly, so as to render the structure 
 capable of shedding water. 
 
 " The branches were fastened to the tree in the middle of 
 the structure by means of wild vines and creepers, which are 
 so abundant in these parts. The projecting limb on which the 
 ape perched was about four feet long. 
 
 " There remains no doubt that these nests are made by the 
 animal to protect it from the nightly rains. When the leaves 
 begin to dry to that degree that the structure no longer sheds 
 water, the owner builds a new shelter, and this happens gene- 
 rally once in ten or fifteen days. At this rate the Nshiego 
 mbouve is an animal of no little industry." 
 
 The roof which this ape builds is from six to eight feet in
 
 TREE- HUTS OF THE WARAUS. 161 
 
 diameter, and is tolerably circular, so that it looks something 
 like a large umbrella. When the animal is at rest it sits on the 
 branch with one arm thrown round the stem of the tree, in 
 order to support itself during sleep. In consequence of this 
 attitude the hair is rubbed away on one side, thus earning for 
 the ape the specific title of calvus, or bald. 
 
 IT is rather remarkable that the Orang-outan of Borneo is 
 likewise a house-builder, though not in the same manner as 
 the African ape which has just been mentioned. This animal 
 has a way of weaving together the branches of trees, so as to 
 make a platform on which it can repose, its enormously power- 
 ful arms being of great service in this task. The animal seems 
 to make its platform in quite a mechanical manner, and it has 
 been noticed that when an Orang-outan has been mortally 
 wounded, it has expended its last energies in twisting the 
 branches together so as to form a couch on which it can lie 
 down and die. 
 
 PUTTING aside those cases where huts have been erected in 
 trees by way of amusement, we may find instances where human 
 beings have been forced to make their habitations in trees. 
 
 In some places, such as certain parts of South America, 
 the natives are forced to make their houses in trees, partly on 
 account of Jthe climate, and partly for the purpose of avoiding 
 the mosquitoes. 
 
 The delta of the Orinoco River is nearly half as large as 
 England, and for a considerable part of the year is deep in 
 water. Yet this tract is inhabited by the Warau tribe, who 
 find in it their only mode of escape from the tiny but terrible 
 mosquito. We in England know but little of the miseries 
 inflicted by these insects, which are so plentiful in some parts 
 of America that they are gathered in bags, pressed into thick 
 cakes about as large as ordinary dinner- plates, and an inch in 
 thickness, and then cooked and eaten. 
 
 Now it is found that although the mosquito infests the 
 banks of rivers, it cannot venture far from land. The Waraus, 
 therefore, make for themselves habitations which are far 
 enough from land to baffle the mosquitoes, and near enough 
 to be easily reached in canoes. 
 
 M
 
 162 NATUKE'S TEACHINGS. 
 
 Fortunately for them, there is a tree called the Ita Palm, 
 belonging to the genus Mauritia, which loves moisture, and 
 grows abundantly in this delta. The Waraus, therefore, make 
 their habitations in these trees, connecting several of them 
 together with cross-beams, and laying planks upon them so as 
 to form the flooring of their simple huts. Here they maintain 
 themselves chiefly by fishing, but are sometimes obliged to 
 visit the mainland, in spite of the mosquitoes. When, how- 
 ever, they return, they halt at some distance from the shore, 
 and with green boughs carefully beat out every mosquito from 
 the canoe before they dare to approach their dwellings. 
 
 The once-celebrated Lake Dwellers of Switzerland evidently 
 lived after a similar fashion. 
 
 IN this case insects drive human beings into trees, but there 
 are instances where nobler animals have produced the same 
 effect. 
 
 Some years ago there lived in Southern Africa a powerful 
 chief called Moselekatze, who spent his whole life in warfare, 
 converting all the male inhabitants into soldiers, dividing them 
 into regiments, ruling them with the extreme of discipline, and 
 by their aid devastating the neighbouring countries. He 
 swept off all the cattle, which constitutes the wealth of the Kafir 
 tribes, and either killed the male inhabitants or pressed them 
 into his service. 
 
 The land was in consequence deprived of its natural de- 
 fenders, and the wild beasts, especially the lions, increased 
 rapidly, so that the position of the survivors was a really 
 terrible one. They had no cattle to furnish the milk which 
 is the chief food of the Kafir tribes ; their weapons had been 
 taken by Moselekatze ; and they were forced to live almost 
 entirely on locusts and wild plants. By degrees the lions became 
 so numerous and daring, that the slight Kafir huts were an 
 insufficient protection during the night, and the disarmed and 
 half -starved inhabitants were perforce obliged to make their 
 habitations in trees. 
 
 Dr. Moffat, the well-known missionary, saw one tree' in 
 which there were no less than twenty huts. They were 
 conical, and made of sticks and grass, the base resting upon a 
 platform or scaffold laid upon the fork of a horizontal branch.
 
 SNOW-HOUSES. 
 
 163 
 
 The only mode of approach to these huts was by notches cut 
 in the trunk of the tree. 
 
 How needful were these precautions was shown by the fact 
 that the missionary himself spent a night in one of these aerial 
 huts, and had the pleasure of hearing a number of lions snarl 
 and growl all night over a rhinoceros hump which he had 
 placed in an oven made of a deserted ant-hill. The oven, 
 however, was too hot for the lions, and they had to retreat at 
 daylight. 
 
 PASSING from the tropics to the polar regions, we now take 
 an instance where man has acknowledgedly copied an animal in 
 the construction of his dwelling. 
 
 In Esquimaux-land, where no trees can grow, where for 
 months together the sun never rises above the horizon, where 
 the temperature is many degrees below zero, and where the 
 land and ice are alike covered with a mantle of snow so thick 
 that every landmark is abolished, it would seem that no human 
 
 SNOW-HOUSE OP SEAL IN ESQUIMAUX-LAUD. 
 
 SNOW-HOUSE OF ESQUIMAUX. 
 
 beings could support life for one week. There is neither 
 timber for house- building nor wood for fuel, so that shelter, 
 warmth, and cookery seem to be equally impossible, and as 
 these are among the prime necessities of human life, it is not 
 easy to see how mankind could exist. 
 
 Yet these very regions are inhabited by sundry animals, and 
 it is by copying them that Man can keep his place. We have 
 already seen how the Esquimaux hunter copies the Polar Bear, 
 and we have now to see how he copies the Seal in the material 
 and form of his dwelling-house, and not only contrives to live, 
 but to enjoy life all the more for the singular conditions in 
 
 M 2
 
 164 NATURE'S TEACHINGS. 
 
 which he is placed. Captain Hall mentions, in his "Life with 
 the Esquimaux," that one of the natives, named Kudlago, who 
 was returning to his native country after visiting the United 
 States, died while on board the ship. Towards the end of his 
 life he was yearning for ice, and his last intelligible words 
 were, " Do you see ice ? Do you see ice ? " 
 
 On the vast plains of ice that are formed in the winter-time 
 the snow lies thickly, and yet upon such an inhospitable spot 
 the mother seal has to make a home for her tender young. 
 This she does in the following manner : 
 
 She has already preserved a " breathing hole " in the ice, 
 through which she can inhale air. How she finds so small a 
 hole under the surface of the ice, where there are no landmarks 
 to guide her, is a marvel to every swimmer. She has to chase 
 fish and follow them in all their winding courses, and yet, 
 when she is in want of air, is able to go straight to her breath- 
 ing hole, and there take in a fresh supply of oxygen. 
 
 When she is about to become a mother, she enlarges this 
 breathing hole so as to make it into a perpendicular tunnel. 
 She then, with the sharp nails of her fore-paws, or flippers, 
 scoops away the snow in a dome-like form, as shown in the 
 illustration, taking the snow down with her through the ice, 
 and allowing it to be carried away by the water. By degrees 
 she makes a tolerably large excavation of a hemispherical shape, 
 and when her young is born she deposits it on the ice-ledge 
 around the tunnel. From ordinary foes the young Seal is safe, 
 and nothing can discover the position of the house unless 
 guided by the sense of smell. 
 
 How the Polar Bear and the Esquimaux hunter discover the 
 dwelling and capture the inmates we have already described 
 in the chapter treating of War and Hunting. Our present 
 business is with the dwelling itself. Comparatively few of 
 these snow-houses, or igloos, as they are called, are dis- 
 covered, and they remain intact until the summer sun melts 
 the roof and exposes the habitation. By this time, however, 
 the young Seal has grown sufficiently to shift for itself, and no 
 longer needs the shelter of a dwelling. 
 
 THE winter hut, or igloo, of the Esquimaux is made of 
 exactly the same shape and of similar materials to the dwelling
 
 SNOW ARCHITECTURE. 165 
 
 of the Seal, the chief difference being that it is built instead of 
 excavated. 
 
 In order to save time, the igloo is generally erected by two 
 men, one of whom supplies the material, and the other acts as 
 bricklayer and architect in one. Each begins by tracing a 
 suitably sized circle in the snow, which he clears away to 
 some depth, so as to preserve a firm surface, either as a floor 
 or as the material for the wall. In this work both men are 
 equally valuable, for the skill required to cut the slabs of snow 
 into such a shape that they can be formed into a hemispherical 
 dome is quite as much as that which is needed for putting 
 them together. I will call them the cutter and the builder. 
 Sometimes a young hand is employed by way of labourer, 
 and passes the snow slabs to the builder as fast as they are cut. 
 
 The builder receives the slabs, and arranges them in regular 
 order, always taking care to " break the joints," just as do our 
 bricklayers of the present day. Always remaining within the 
 circle, he gradually builds himself in, and when he has quite 
 finished the house, he cuts a hole through the side, emerges, 
 and, by the help of his partner, puts on the finishing touches. 
 He usually also adds a sort of tunnel to the door, through 
 which any one must creep on his hands and knees if he wishes 
 to enter the igloo. This part of Esquimaux architecture will 
 presently be noticed more in full. 
 
 Perhaps the reader may wish to know what provision there 
 is for ventilation. The answer is simple enough. There is 
 none, the Esquimaux not requiring ventilation any more than 
 they require washing. The two, indeed, generally go together ; 
 and it may be observed, even in our own country, that those 
 who object to fresh air, and are always complaining of 
 draughts, have a very practical aversion to the use of fresh 
 water, and but little confidence in what Thackeray calls the 
 " flimsy artifices of the bath." 
 
 The Esquimaux never washes, and knows not the use of 
 linen. Consequently, it is no matter of surprise that a sailor 
 of Captain Hall's crew could not make up his mind to enter an 
 igloo. " Whew ! " exclaimed the man, " by thunder, I'm not 
 going in there ! It's crowded, and smells horribly. How it 
 looms up ! " 
 
 Considering that there were inside that igloo a dozen
 
 166 
 
 NATURE S TEACHINGS. 
 
 Esquimaux, all feasting on a raw, newly killed, and yet warm 
 seal, the sailor had reason enough to decline a visit. Captain 
 Hall, however, determined, in his character of explorer, to 
 brave the strange odours, and moreover to join the inmates in 
 their feast, knowing that as he would have to live among the 
 Esquimaux for some two years, he would be forced to live as 
 they did, and might as well begin at once. Consequently on 
 this resolve, he drank the still steaming blood, and quaffed it 
 from a cup which an Esquimaux woman had just licked clean. 
 
 FLOORS AND PILLARS. 
 
 ONE decided step in Architecture is the invention of the 
 Pillar, and its capabilities of aiding to sustain another floor 
 above it. We see this principle carried out in our great cathe- 
 drals, where the use of the Pillar is almost infinite. Take, for 
 example, Canterbury Cathedral. A heedless visitor might 
 easily pass through the nave, enter the choir, visit the various 
 
 WASP-COMBS. 
 
 SLAVE SHIP. 
 
 side-chapels, and "Becket's Crown," without thinking that 
 under his feet is a vast chamber, and that the floor on which 
 he stands is, in fact, the roof of a great crypt. 
 
 The weight of the Cathedral, with its lofty towers, is so 
 tremendous, that the building could not be erected simply 
 upon the ground, but rests upon a complicated substratum of 
 pillars and arches, whereby the weight is spread over a large 
 surface. In fact, the Cathedral is really two buildings, the 
 one erected upon the other. 
 
 IN Nature there are many instances of pillars supporting 
 different floors. One of the most beautiful examples is to be
 
 CUTTLE-BONE. 167 
 
 seen in the common Cuttle-bone, as it is called, this being the 
 internal skeleton, if it may be so termed, of the common Sepia 
 (Sepia officinalis), which is so often found on our coasts, especially 
 after a gale. This year (1875) I found eight of these Cuttle- 
 bones on the Margate sands, and all within a space of some 
 twelve feet square. 
 
 This so-called bone is really composed of the purest chalk, for 
 which reason it is in great request as a dentifrice, being easily 
 scraped to almost impalpable powder when wanted, and not liable 
 to be spilled, as is the case with any ordinary tooth-powder. 
 
 It is exceedingly light so light, indeed, that it floats like a 
 cork, even in fresh water. Now, as chalk is very much heavier 
 than water, we may naturally ask ourselves how this lightness 
 is obtained. If the upper surface be examined, it will be seen 
 to be traversed by a vast number of wavy lines, something like 
 the markings of " watered " silk. These show the lines of 
 demarcation between the multitudinous rows of pillars of 
 which the whole structure is formed. 
 
 If the " bone " be sharply snapped in the middle, and the 
 particles of white dust blown away, a wonderful structure 
 presents itself, which can be partially discerned by the naked 
 eye, though a microscope is required to bring out its full 
 beauties. 
 
 Even with an ordinary pocket lens we can make out some 
 of its wonders. The object looks like a vast collection of 
 basaltic columns, except that the pillars are white instead 
 of black, and they are arranged in rows with the most perfect 
 accuracy, just as if the place of each had been laid down 
 with rule and compass. They are scarcely thicker than 
 ordinary hairs, but they are beautifully perfect, and rise in 
 tier after tier as if they were parts of a many-storied building. 
 As a definite space exists between the pillars, the reader will 
 understand why the whole structure should be so much lighter 
 than water. In order, however, to see these wonderful pillars 
 in perfection, a very thin section should be taken, and viewed 
 with polarised light. 
 
 ANOTHER excellent example of Pillars and Flooring is to be 
 found in the nests of various Wasps, including that of the 
 Hornet.
 
 168 NATURE'S TEACHINGS. 
 
 In these nests the combs are arranged horizontally, and not 
 vertically, like those of the bees, and in consequence they have 
 to be supported in some way. This object is achieved by 
 means of multitudinous pillars made of the same papier-mache 
 of which the combs are formed, and attached to the successive 
 rows of combs. There is, however, one curious point of 
 difference between the "Wasp-comb and human architecture, 
 namely, that the pillars do not support floors, or rest upon 
 them, but sustain the weight of those which hang from them. 
 The mouths of the cells are all downwards, and the combs are 
 therefore suspended from the pillars, instead of being supported 
 by them. 
 
 TUNNEL ENTRANCE TO THE DWELLING. 
 
 WE have already found occasion to treat of the snow-house, 
 or igloo, of the Esquimaux, and have now to speak of a sub- 
 sidiary, though necessary, part of Esquimaux architecture. 
 
 Perhaps the reader may have been unfortunate enough to 
 travel by rail in the depth of winter, and to be associated with 
 fellow-passengers who will insist on closing every window, 
 even though the carriage be crowded. Suppose that on such 
 a day, the weather being perfectly fine, the train stops at a 
 station, and the guard outside opens the door to see if another 
 passenger can be accommodated with a place. 
 
 No sooner is the door opened than a shower of snow at 
 once fills the carriage. This is simply the moisture suspended 
 in the air and generated by human lungs. The rush of cold 
 air at once freezes this moisture and converts it into snow, thus 
 showing those who will condescend to learn, that they have 
 been breathing and re-breathing the air that has passed through 
 a variety of human lungs, and is charged with their different 
 moistures. I have seen the same phenomenon at a dinner 
 party, where, after the withdrawal of the ladies, one of the 
 windows was opened. 
 
 Now, in Esquimaux-land, it is absolutely necessary to con- 
 serve every atom of heat, for the cold is so intense that if a 
 cask of water be near a coal fire, only the part next the fire 
 will be thawed, the rest being ice. Cold, therefore, is a foe 
 which has to be fought and kept away from the household. 
 Then there are other foes such as Polar Bears, for instance
 
 TUNNEL ENTRANCES. 
 
 169 
 
 which would be only too glad to get into an igloo and make a 
 meal of its inhabitants. The Esquimaux architect, therefore, 
 avails himself of an ingenious device by which he can set both 
 foes at defiance. 
 
 In summer-time he contents himself with a hut made of 
 skins, and merely hangs a skin over the entrance by way of a 
 door. But in the winter, when he is driven to his snow-house 
 
 NESTS OP FAIEY MARTIN. 
 TOWEKS OF SAND-WASP. 
 
 HUTS OF ESQUIMAUX. 
 
 for shelter, he acts in a very different manner. Instead of 
 merely cutting an aperture for a door in the side of the igloo, 
 he constructs a long, low, arched tunnel, so small that no one 
 can enter the igloo except by traversing this tunnel on his 
 hands and knees. Sometimes a number of huts are con- 
 nected with each other, one or two tunnels leading into the air, 
 and the rest serving merely as passages from one hut to the 
 other. 
 
 IN Nature are several examples of tunnels constructed on 
 the same principle. 
 
 There are, for instance, the curious nests of the Fairy Martin 
 of Southern Australia (Hirundo Ariel), which bear a singular 
 resemblance to oil-flasks, the body of the nest being rather 
 globular, and the only entrance being through a tolerably long, 
 tunnel-like neck. 
 
 Then there are the various Weaver-birds of Africa, with 
 their long-necked nests. Some of these strange edifices look
 
 170 NATURE'S TEACHINGS. 
 
 almost like horse-pistols suspended by the butt, so round is the 
 nest, and so long and narrow is the tunnel-like entrance. 
 
 PASSINO to the insect world, we find the same principle 
 carried out by the now familiar Mason- wasp (Odynerus mura- 
 rius), some of whose nests are represented in the illustration. 
 
 This insect makes a burrow, and at the bottom of it deposits 
 an egg, together with a number of little caterpillars on which 
 the grub, when hatched, will feed. The mother Wasp is not 
 allowed to pursue this task without taking precautions against 
 the admission of enemies to her burrow, especially the ichneu- 
 mon-flies. As may be inferred from its popular name, the 
 Sand -wasp always selects a sandy spot for its burrow, and 
 generally chooses a piece of tolerably hard sandstone, which it 
 is able to bite into little pellets, aided by a kind of liquid which 
 it secretes. 
 
 The following account of the manner in which the Mason- 
 wasp forms and defends its home is taken from the invaluable 
 " Insect Architecture," by Rennie. 
 
 The author begins by describing the form and depth of the 
 burrow, and the soil in which it is made. He then proceeds to 
 show the wonderful manner in which the mother Wasp purveys 
 food for the use of her future young whom she will never see. 
 Guided by instinct, she places in the burrow exactly the 
 number of caterpillars which the young Mason-wasp will have 
 to consume before it attains its perfect condition. It is believed 
 that she partially paralyzes them with her sting before 
 placing them in the burrow. At all events, when they are 
 once packed away, they never move, so that the tiny Wasp grub 
 can feed upon them quite at its leisure. 
 
 Here is Eennie's account of the Sand- wasp and her burrow- 
 making : 
 
 " When this wasp has detached a few grains of the moistened 
 sand, it kneads them together into a pellet about the size of 
 one of the seeds of a gooseberry. 
 
 " With the first pellet which it detaches, it lays the founda- 
 tion of a round tower, as an outwork, immediately over the 
 mouth of its nest. Every pellet which it afterwards carries off 
 from the interior is added to the wall of this outer round tower, 
 which advances in height as the hole in the sand increases in
 
 TOWER OF THE SAND-WASP. 171 
 
 depth. Every two or three minutes, however, during these 
 operations, it takes a short excursion, for the purpose probably 
 of replenishing its store of fluid wherewith to moisten the sand. 
 Yet so little time is lost, that Reaumur has seen a mason- wasp 
 dig in an hour a hole the length of its body, and at the same 
 time build as much of its round tower. 
 
 " For the greater part of its height this round tower is per- 
 pendicular, but towards the summit it bends into a curve, 
 corresponding to the bend of the insect's body, which, in all 
 cases of insect architecture, is the model followed. The pellets 
 which form the walls of the tower are not very nicely joined, 
 and numerous vacuities are left between them, giving it the 
 appearance of filigree- work. 
 
 " That it should be thus slightly built is not surprising, for 
 it is intended as a temporary structure for protecting the insect 
 while it is excavating its hole, and as a pile of materials, well 
 arranged and ready at hand, for the completion of the interior 
 building, in the same way that workmen make a regular pile 
 of bricks near the spot where they are going to build. This 
 seems, in fact, to be the main design of the tower, which is 
 taken down as expeditiously as it has been reared. 
 
 " Reaumur thinks, that by piling in the sand which has pre- 
 viously been dug out, the wasp intends to guard its progeny 
 for a time from being exposed to the too violent heat of the 
 sun ; and he has sometimes even seen that there were not 
 sufficient materials in the tower, in which case the wasp had 
 recourse to the rubbish she had thrown out after the tower was 
 completed. By raising a tower of the materials which she 
 excavates, the wasp produces the same shelter from external 
 heat as a human being would who chose to inhabit a deep 
 cellar of a high house. 
 
 " She further protects her progeny from the ichneumon-fly, 
 as the engineer constructs an outwork to render more difficult 
 the approach of an enemy to the citadel. Reaumur has seen 
 this indefatigable enemy of the wasp peep into the mouth of 
 the tower, and then retreat, apparently frightened at the depth 
 of the cell which she was anxious to invade." 
 
 It is no wonder that the Sand- wasp should be so anxious to 
 insure the safety of her nest, for her foes are multitudinous. 
 Putting aside the ordinary Ichneumon-flies, we have the pre-
 
 172 NATURE'S TEACHINGS. 
 
 datory Tachinae, which are always hovering over such nests, and 
 trying to deposit eggs therein. For many years I have been 
 in the habit of receiving letters from novices in entomology, 
 wanting to know whether I am aware that the common House- 
 fly is in the habit of acting as a parasite. Of course, the 
 writer has mistaken the Tachina for a house-fly, but I cannot 
 regret the fact that some one has really begun to observe 
 Nature, and not only to read books. 
 
 DOORS AND HINGES. 
 
 HAVING seen that both in Nature and Art the entrances to 
 dwellings are guarded by tunnel-like approaches, we come 
 naturally to another mode of guarding the entrance, namely, 
 by a door moving on hinges. As to the multitudinous examples 
 of doors and hinges in modern civilisation, we need hardly dis- 
 cuss them, except to show the exact analogies which occur in 
 Art and Nature. 
 
 Doors moving on hinges are very plentiful in Nature, even 
 where we should least expect them. Take, for example, an egg, 
 especially the egg of an insect, and we shall see that it is just 
 about the last object in which we should expect to find a hinged 
 door. Yet, if the reader will refer to the illustration on page 7, 
 he will see that the tiny eggs of the common Gnat, numerous 
 as they may be, are each furnished with a door which opens 
 as soon as the inmate is hatched, and allows the little larva 
 to escape into the water. 
 
 Another still more remarkable instance of a hinged door in 
 an egg is to be found in one of the Rotifers, or Wheel- Animal- 
 cules, so called because they possess an apparatus of movable 
 cilia, which, when set in motion, looks exactly like a wheel 
 running round and round. As the full-grown creature is barely 
 one thirty-sixth of an inch in total length, the structure of its 
 eggs must be infinitesimally beyond the range of human vision. 
 
 Yet, just as the telescope sets at partial defiance the vast 
 spaces that intervene between our earth and her sister planets, 
 so the microscope performs a similar task in the infinitesimally 
 minute. And, under the all-revealing lens of the microscope, 
 the little egg of the Brachionus, though absolutely invisible to 
 the unaided eye, yields up its secrets.
 
 EGG OF THE BRACH1ONUS. 173 
 
 Fortunately, the shell is so transparent that the interior of 
 the egg can be seen through it as if it were a mere film of glass. 
 The astonishing division and re-division of the yolk take place 
 before our eyes, being divided first into two, then into four, 
 then into eight, then into sixteen, then into thirty-two, and so 
 on, until the whole mass of the yolk is cloven into divisions too 
 numerous to count. 
 
 By degrees, the form of the young Brachionus is developed 
 within the egg, even to the very teeth, which work away as 
 persistently as if large stores of food were being passed through 
 them. 
 
 When the young is ready to take its place in the world, a 
 new development occurs, which has been well related by 
 Mr. Gosse: 
 
 " All these phenomena have appeared in the egg we are now 
 watching ; and at this moment you see the crystalline little 
 prisoner, writhing and turning impatiently within its prison, 
 striving to burst forth into liberty. 
 
 " Now, a crack, like a line of light, shoots round one end of 
 the egg, and in an instant, the anterior third of the egg is 
 forced off, and the wheels of the infant Brachionus are seen 
 rotating as perfectly as if the little creature had had a year's 
 practice. 
 
 " Away it glides, the very image of its mother, and swims to 
 some distance before it casts anchor, beginning an independent 
 life. At the moment of escape of the young, the pushed-oif 
 lid of the egg resumes its place, and the egg appears nearly 
 whole again, but empty and perfectly hyaline (i.e. all but 
 transparent), with no evidence of its fracture, except a slight 
 interruption of its outline, and a very faint line running 
 across it." 
 
 To pass from the egg to a more advanced stage in life. All 
 practical entomologists have been greatly annoyed, in their earlier 
 years of collecting, to lose larva after larva, from the attacks of 
 Ichneumon-flies. It is certainly rather beyond the limits of 
 ordinary patience to discover, watch over, and secure successfully 
 a rare caterpillar, and then to find that it has been " stung " by 
 an Ichneumon-fly. 
 
 The veteran entomologist, however, troubles himself very 
 little about such, minor misfortunes, and, as a rule, more than
 
 174 NATURE'S TEACHINGS. 
 
 compensates for them by preserving the intrusive Ichneumon- 
 fly, and giving in his diary full details of the insect on which 
 it was parasitic, of the plant on which the caterpillar lived, the 
 date of its appearance, and its numbers. 
 
 Now, there are many of these parasitic insects, notably those 
 belonging to the genus Microgaster, which invariably make 
 doors in their cocoons. I have now before me groups of 
 cocoons made of the two commonest British species, namely, 
 Microgaster glomeratm and Microgaster alvearius, and in both 
 of them each tiny cocoon is furnished with a hemispherical, 
 hinged door. I have also some exquisitely beautiful groups 
 of Microgaster cocoons found in the West Indies. They 
 are the purest white, shine with a satiny lustre, and are 
 arranged round a hollow centre, much as if they had been 
 gummed to the outside of a very large thimble. There are 
 many hundreds of them, and every one has its little door 
 still open as it was when the fully developed insect first made 
 its escape. 
 
 ANOTHER curious example of a natural door may be seen by 
 those who will look for it. 
 
 On plants infested with aphides, or " green blight," as the 
 gardeners quaintly term them, may often be seen dead aphides 
 much larger than the rest, globular, brown, and shining. 
 These aphides have been " stung," as it is called, by a little 
 Ichneumon-fly belonging to the genus Ophion, and having, 
 like all its congeners, a flat and sickle-shaped abdomen. The 
 egg which has been laid in the aphis soon hatches, and the 
 young Ophion absorbs into itself all the juices of the aphis. 
 It remains within the body of its involuntary host until it is 
 fully developed, when it cuts a tiny, but beautifully perfect 
 circular door in the skin, and emerges, leaving the door open 
 and still attached by its little hinge. 
 
 Considering the small size of the aphis, and that the dia- 
 meter of the door is only one-eighth of the length of the insect, 
 the perfection of its form is really remarkable. 
 
 ONE of the achievements of modern Architecture is the Self- 
 closing Door, especially where it must of necessity close by its 
 own weight, and when the fitting is so exact, that even the
 
 TRAP-DOOR SPIDER. 175 
 
 most experienced eye can scarcely detect it. Such a door is to 
 be found guarding the nest of the Trap-door Spiders, several 
 species of which are found scattered over all the warm parts of 
 the earth. A side view of one of these extraordinary nests is 
 
 DOOR OF TBAP-DOOK SLIDER. TKAP-DOOE OP COAL-CKLLAK. 
 
 given in the accompanying illustration, and on the other side is 
 the common trap-door of our cellars. 
 
 The Spiders which make these extraordinary dwellings 
 generally begin by excavating a nearly perpendicular tunnel in 
 the ground. They line it with a silken web, and construct a 
 door which exactly fits the orifice, and which is bevelled so that 
 it shall not sink too far, and thus betray itself. I have seen and 
 handled one, where the burrow had been sunk among lichens 
 and mosses, and the trap-door of the nest had been most inge- 
 niously covered with the same growths. Although the surface of 
 the slab of earth in which the nest was made is only a few 
 inches square, it is almost impossible to detect the entrance, so 
 admirably do the mosses on the door correspond with those 
 outside it. 
 
 Almost invariably the nest is sunk in the ground, but I have 
 a specimen sent to me from India, in which the Spider must 
 absolutely have carried the clay to a fluted pillar, burrowed in 
 it, and then made its beautiful habitation. The nest and its 
 inhabitant were sent to me by an officer in the 108th Regiment, 
 accompanied by the following letter : 
 
 " The packet contains a large Spider and the upper portion 
 of its peculiar nest, the history of which is as follows. 
 
 " On the thirtieth of last month (September, 1870), while 
 searching for caterpillars on a bush growing close to one of the 
 pillars of my verandah, which is a very low one, reaching to 
 within a foot of the ground, I saw in part of the chunam 
 masonry at the foot of the pillar what I at first sight took to be
 
 176 NATURE'S TEACHINGS. 
 
 a couple of seeds sticking to a stone. On trying to pull one off, 
 I found that it came up with ease, bringing with it what I 
 thought was the stone. 
 
 " But I had scarcely got it up when it was smartly pulled 
 back. This excited my curiosity, and I raised it again with a 
 little force. I now saw, to my wonder and admiration, that what 
 I had fancied was a stone was a small circular door with a 
 pretty broad hinge, made all of silk; and then distinctly 
 observed a large black spider dart down the hole to which the 
 above door gave an entrance. But, not knowing the depth, I 
 broke it. 
 
 " This piece I send to you, together with its original owner, 
 who, at the beginning of my digging operations, ran up sud- 
 denly, shut the door in my face, and hung on to it like grim 
 death when I tried to reopen it. He soon came away with the 
 upper piece, still keeping the door resolutely closed."
 
 ARCHITECTURE. 
 
 CHAPTER II. 
 
 WALLS, DOUBLE AND SINGLE. PORCHES, EAVES, AND 
 WINDOWS. THATCH, SLATES, AND TILES. 
 
 The Wall and its Materials. Bricks as they are and might he. Trade Union- 
 ism. Double Walls and their Uses. Double Clothing. The Refrigerator. 
 Cooking Vessels. Fire-proof Safes. Cocoon of the Silkworm, and its treble 
 Walls. Nest of the Little Ermine, Processionary, Gold -tailed, and Brown- 
 tailed Moths. Mud Walls. Nests of the Termite. Porches, Eaves, and 
 Windows. Nests of the Myrapetra and an Indian AUG. The Sociable 
 Weaver-bird and its Nest. Thatching. Arms of the Orang-outan. 
 Japanese and Chinese Rain-cloaks. Eggs of the Gold-tailed Moth. Action 
 of Fur. Slates and Tiles. Scales of Butterfly's Wing. Shell of Tortoise. 
 Scales of Manis, Fish, and Armadillo. 
 
 WE now come to the Walls of the house, in which there is 
 more variety than might be imagined. 
 
 Take, for example, our modern houses of the "villa" type. 
 They are nothing but the merest shells, made of the flimsiest 
 imaginable materials. Some years ago, while walking through 
 a suburb where some very showy houses were being built, I 
 amused myself by going over them and testing them. There 
 was scarcely a room in which I could not thrust an ordinary 
 walking-stick through the wall. When they were " finished" 
 and "pointed," the houses looked beautiful, but their heat in 
 summer, cold in winter, and moisture in wet weather, can easily 
 be imagined, especially as the sand with which the mortar was 
 mixed had been procured from the banks of a tidal river. 
 
 There is not the least necessity for such buildings. It is absurd 
 to run up such edifices as that, and then charge 120 per 
 annum for rent. The whole system is as rotten as the houses, 
 and there is nothing but prejudice and trade-unionism to pre- 
 vent our houses being cool in summer, warm in winter, and dry 
 in all weathers.
 
 178 
 
 NATURE S TEACHINGS. 
 
 It is well known that air is practically a non-conductor of 
 heat, and that therefore a layer of air between two very slight 
 walls is just as warm as if the wall had been made of solid 
 stone. Now, there are several inventions whereby the present 
 brick could be made half its present weight, twice its present 
 
 FUtt. NEST OF LITTLE E::MIXE-MOTH. 
 
 strength, hard and smooth as earthenware, so that it could not 
 absorb water like our common brick, and pierced with holes 
 through which air could pass. 
 
 Unfortunately, however, there is a stringent rule among brick- 
 makers and bricklayers that they are to play into each other's 
 hands, and that no bricklayer is to touch a brick which has not 
 been made in some definite district. Should he do so, he is a 
 marked man, and will stand but little chance of getting even 
 a day's work. 
 
 The power of the double wall may be seen in many ways. 
 For example, in the old days of coaching, when one had to pass 
 hour after hour on the roof of the coach, it was known by 
 practical experience that double body linen, and two pairs of 
 stockings, worn one over the other, formed the best preparation 
 for the journey. The reason was, that air became entangled 
 between the layers of fabric, and acted as a non-conductor of 
 heat. 
 
 Another mode of utilising the principle of the double wall is 
 seen in the refrigerators which add so much to the comfort of 
 the household in a hot summer. The one principle of these 
 refrigerators is, to keep a layer of air between the ice and the 
 surrounding atmosphere. The same principle may be used in a 
 reverse way, and heat be preserved instead of repelled. Those
 
 DOUBLE WALLS. 179 
 
 cooking-pots are now well known, where half-cooked meat can 
 be inserted in the morning, and at luncheon-time be turned out 
 quite hot and perfectly cooked. The fact is, that the vessels in 
 question are covered with a very thick layer of felt. The felt, 
 however, is only a device for entangling air, and a double wall 
 would answer the purpose as well, if not better. 
 
 The now well-known fire-resisting safes are made on this 
 principle, and after they have been for hours in a raging fire, 
 and the outer case has become red-hot, the interior is quite 
 safe, the papers uninjured, and even a watch continuing to go. 
 
 Then there is the ordinary Ice-house, a sketch of which is 
 given in the illustration. A pit is first dug in the ground, and 
 thickly lined with dry branches, straw, &c. The roof is con- 
 structed in the same manner, only the non-conducting power 
 is increased by a thick coating of earth over the sticks and 
 straw. The door, which is approached by a shelving cutting, is 
 similarly protected, the covering only being removed when the 
 door is opened. 
 
 I once made a very effective refrigerator out of two hampers, 
 putting a small hamper inside a large one, and packing the 
 space between them with straw. 
 
 IN Nature we find many examples of this principle, which 
 enables the inhabitants to bid defiance to frost. 
 
 A familiar example may be found in the cocoon of the 
 common Silk- worm (Bombyx mori), and indeed in that of almost 
 any silk-producing insect. When the caterpillar is about to 
 make its cocoon, it begins by a number of rather strong threads 
 attached to different points, and making a sort of scaffolding, so 
 to speak, for the cocoon itself. Upon these is spun a slight 
 outer cocoon of very loose and vague texture the "floss silk" 
 of commerce, and within that is the cocoon proper, in which the 
 insect lies enclosed. It will be seen, therefore, that there are 
 really three cocoons, one within the other, namely, the scaffold 
 cocoon, the floss cocoon, and the silk cocoon itself, so that the 
 inmate is protected from variations of temperature. 
 
 The cocoon of the emperor-moth, which has already been 
 described, is made on the same principle. 
 
 There are several caterpillars which are social in their early 
 stages, and which construct a common habitation. The Little 
 
 N 2
 
 180 
 
 NATURE S TEACHINGS. 
 
 Ermine-moth (Hyponomeuta padella) affords a familiar example 
 of this structure. The caterpillars are great roamers in search of 
 food by day, and travel from branch to branch on their strong 
 silken threads. At night, however, they return to a large white 
 silken habitation which they have spun, and which they divide 
 into many compartments, as may easily be seen by cutting the 
 nest open with very sharp scissors. Within this habitation the 
 caterpillars spin their separate cocoons, so that the system of 
 double walls is thoroughly carried out. 
 
 There is another insect, very common on the Continent, but, 
 happily for us, not introduced into England. It is called the 
 Processionary Moth, from its curious habit of marching in exact 
 lines, the head of the second caterpillar touching the tail of the 
 first, and so on. These insects have likewise a common home, 
 and spin their own separate cocoons within it. 
 
 THERE are two other sociable British Moths which make 
 nests on a similar principle. These are the Gold- tailed Moth 
 (Porthesia chrysorrhcea) and the Brown-tailed Moth (Porthesia 
 auriflua). They are both beautifully white insects, but may 
 
 NEST OP PROCESSIONABY 
 MOTH. 
 
 COCOON OP SILK- 
 WORM. 
 
 P'IBEPKOOF SAFE. 
 
 easily be distinguished from each other, the Gold-tailed Moth 
 having some brown-black spots on the upper wings, and a tuft 
 of golden-yellow hairs at the end of the body ; while the 
 Brown-tailed Moth is without spots, and the tail-tuft is brown. 
 In habits they are very similar, and the description of the 
 nest made by one will answer for that made by the other. I 
 believe that broods of these two species have been known to
 
 MUD WALLS. 181 
 
 construct a common nest. The nest is extremely variable in 
 form, because it depends much on the number of twigs which it 
 includes. Interiorly, it is divided into a considerable number 
 of chambers, each containing one or several individuals. 
 
 As the caterpillars are hatched late in summer, they have to 
 undergo the frosts of winter before they can attain their perfect 
 state. Accordingly, before the winter-time comes on, they 
 strengthen both the external walls and internal partitions of 
 their nest, and then wait until the spring brings forth the 
 leafage of the new year. 
 
 The nest is a beautiful structure, and I strongly recommend 
 the reader to look for one in a hedgerow, take it home, and 
 cut it up carefully. I would, however, advise him, if, like 
 myself, he be subjected to a very sensitive skin, to be cautious 
 in his handling of the nest. The hairs with which the pretty 
 black, red, and white caterpillars are studded are irritant in 
 the extreme. 
 
 I have several times suffered from them, and would much 
 rather be severely stung by nettles than undergo the fierce irri- 
 tation, mixed with dull heavy pain, which always accompanies 
 the presence of these hairs. With me, as I suppose would be 
 the case with persons of similar organization, these hairs cause 
 large, hard tubercles to rise, j ust as if potatoes had been placed 
 under the skin. The hairs of the Processionary Caterpillar have 
 a similar effect, and in France the authorities have several times 
 been obliged to close the public gardens for months, so severe 
 was the pain which the caterpillars inflicted on persons who 
 passed through the spots infested by them. 
 
 MUD WALLS. 
 
 THERE is a mode of wall-building which is much in vogue in 
 some parts of England, and has much to commend itself. This 
 is the Mud or Concrete Wall. 
 
 At first sight, the very name of a mud house gives an idea of 
 poverty and misery, and is apt to be connected with hovels 
 and pigsties. Mud walls, however, if properly built, are far 
 warmer and drier than those of brick, and are even preferred to 
 those of stone, when the latter can be easily and cheaply 
 obtained. In Devonshire, for example, where even the cattle- 
 sheds, or "linhays" (pronounced linny] y and the pigsties are
 
 182 
 
 NATURE S TEACHINGS. 
 
 made of the rich red stone of the county, it is a common thing 
 to see village houses built of mud. Sometimes the houses are 
 built of stone to the height of some ten or twelve feet, and the 
 upper parts made of mud. 
 
 If the builders are in any way fastidious, they make their 
 walls of a uniform surface by placing two rows of planks on 
 
 NEST OF TERMITE. 
 
 MUD WALL. 
 
 their edges at a distance from each other proportionate to the 
 thickness of the wall, pouring the mud between them, and, 
 when it has sufficiently hardened, shifting the planks. This, 
 however, is not necessary, and detracts much from the pic- 
 turesque look of a genuine mud wall, especially when it is of 
 that rich red which characterizes the Devonshire soil. These 
 mud walls are locally known by the name of Cob. 
 
 WE have not to go very far in Nature to find good examples 
 of the strength which can be attained by mud walls. 
 
 In all parts of the world where Termites, popularly but 
 wrongly called White Ants, are to be found, the strength and 
 endurance of the mud wall can easily be tested. Of gigantic 
 dimensions when compared with the size of the architect, they 
 not only endure the rain-torrents which wash over them, but 
 can sustain the weight of the wild cattle, which are in the habit 
 of using them as watch-towers, and this although they are 
 hollow, and filled with chambers and galleries. 
 
 In Southern Africa these nests are much utilised. There is 
 an animal called by the Dutch settlers the Aard-vark, which
 
 PORCHES, EAVES, AND WINDOWS. 
 
 183 
 
 feeds almost wholly on Termites. At night it issues from its 
 burrow, and, being armed with large and powerful claws, tears 
 a great hole in the side, and devours the inmates. 
 
 These deserted nests are sometimes used as ovens, as we have 
 already seen, a fire having been kindled within them for some 
 time, the meat, well enveloped in leaves, being thrust into 
 them, and the opening closed with clay. Sometimes they are 
 used as graves, the corpse being placed in them, and the hollow 
 filled up with earth, while the wall of the Termite nest, when 
 pounded and mixed with water, is found to be the most tenacious 
 clay that can be used for building or flooring huts. 
 
 PORCHES, EAVES, AND WINDOWS. 
 
 WE now come to some of the appendages of a house, nameiy, 
 the Porch by which the rain is kept from a doorway, the Eaves 
 by which it is kept from the walls, and the Windows which 
 will admit light and air, but will prevent the entrance of 
 intruders. 
 
 We first take the Porch, two examples of which are shown 
 in the accompanying illustration, one being the work of human 
 hands, and the other that of an insect. 
 
 The figure on the right hand represents an old-fashioned 
 Porch, such as is often to be seen attached to old village 
 churches, and which, being furnished with seats, serves also as 
 a resting-place for those who are weary. 
 
 NE8T8 OP MYRAPETRA, WITH PORCHES. 
 
 The figure on the left hand of the illustration is a wonderful 
 example of the Porch, as constructed by insects. It is the
 
 184: NATURE'S TEACHINGS. 
 
 nest of a honey-making Brazilian wasp named Hyrapetra 
 scutellaris. The peculiarity of this nest consists in its exterior 
 being covered with a vast number of projections made of the 
 same material as the walls of the nest, but more solid and much 
 harder. The colour of the nest is blackish brown. 
 
 The object of all these projections has not been ascertained, 
 but there is no difficulty as regards some of them. Without a 
 very careful examination, it is exceedingly difficult to see any 
 opening by which the inhabitants of the nest can go in and 
 out. It will be found, however, that there are many entrances, 
 which are set in a row round the nest, each opening being 
 situated under a projection, which thus performs the office of a 
 porch as well as that of concealment. 
 
 Another hymenopterous insect carries out the principle of the 
 Porch in its nest. This is the Myrmica Kirbyi, a tiny reddish 
 Ant which inhabits India. It makes its nest of cow-dung, which 
 it works up into a texture very like that of an ordinary wasp- 
 nest. A series of large flakes of this substance overhang the 
 entrances, so that the inhabitants can enter freely, while rain 
 is kept out. For the purpose of greater security, one very 
 large flake covers the roof in umbrella fashion. The whole 
 nest is globular, and about eight inches in diameter. 
 
 NEXT we come to the projecting Eaves, like those of our 
 houses, and serving to preserve the body of the edifice itself 
 from wet. On the right hand of the illustration there is an 
 example of the eaves as they are still to be seen in some of 
 our country places, where the less picturesque slates have not 
 yet superseded the old thatch. In some places these eaves 
 extend considerably beyond the walls, and I know of several 
 instances, especially in North Devon, where a supplementary 
 set of eaves extends, like a penthouse, throughout the length of 
 the building, and just above the windows of the ground-floor. 
 
 The reader will remark that the projections upon the 
 Myrapetra's nest may very well fulfil the office of eaves as 
 that of porches, and not only shelter the entrances, but serve to 
 shoot the wet off the walls of the nest. 
 
 ON the left hand of the illustration are several instances of 
 eaves as existing in Nature.
 
 THATCH. 
 
 185 
 
 In the centre is the compound nest of the Sociable Weaver- 
 bird of Southern Africa (Philetarm socius). 
 
 This is a dwelling constructed very much after the fashion 
 adopted by many hymenopterous insects, namely, that each pair 
 of birds make their own individual nest, but unite with their 
 
 DWELLING OP SOCIABLE WEAVER-BIRD, WITH THATCH. 
 THATCHED EGOS OF GOLD-TAILED MOTH. 
 
 THATCHED HOUSE. 
 
 companions in constructing a common roof or covering. More 
 than three hundred nests have been found in a single habita- 
 tion, and sometimes the birds miscalculate, or rather, do not 
 calculate the resisting power of the branches, and, when the 
 rainy season comes, the additional weight of water brings down 
 the whole edifice with a great crash. 
 
 The thatch which covers this congeries of nests is made of 
 the Booschmannees-grass, whose long leaves and tough wiry 
 stems are admirably adapted for throwing off water, even 
 though they be not bound together like our more regularly 
 constructed thatch. 
 
 Perhaps the reader may be aware that in the Orang-outan, 
 the Chimpansee, and other large apes, the hairs of the arms 
 are very long, and point in different directions, so that if the 
 creature should be caught in a rain-storm, and, after the manner 
 of its kind, fold its arms on its breast, with the hands resting 
 on the shoulders, the rain is shot clear of its body, the hairs 
 performing the duty of eaves. 
 
 Both Japan and China have a rain-cloak, constructed on
 
 186 NATURE'S TEACHINGS. 
 
 exactly the same principle as the thatch of the Sociable Weaver- 
 bird. They are nothing more than successive rows of long 
 grass-blades fastened to a network of the proper shape. No 
 amount of rain or snow can wet them through, and they have 
 the advantage of being pervious to the exhalations of the body, 
 though impervious to external moisture. 
 
 In this respect they are greatly superior to our waterproof 
 coats, for, if the wearer has to undergo much bodily exertion, 
 or is obliged to wear it for any length of time, he finds his 
 clothing nearly if not quite as wet as if he had allowed the pure 
 rain to fall on him from the clouds. I possess specimens of 
 each kind of cloak. 
 
 When I procured them they were quite blackened with 
 London smoke, and, on account of their resistance to water, 
 washing them was a very long and troublesome business. 
 
 Above the nest are two patches of the Booschmannees-grass, 
 as they appear when laid by the bird. 
 
 BELOW the nest is a group of the eggs of the Gold-tailed 
 Moth, whose nest has already been described. Perhaps the 
 reader wonders where the eggs are. Owing to the mode in 
 which they are arranged, only a few can be seen, and are 
 represented by the little white spots in the lower part of the 
 figure. When the Gold-tailed Moth is ready for the great 
 business of laying her eggs, she seeks a suitable place, and 
 then piles them up in the form of a shallow cone. Her task, 
 however, is not yet finished. Having arranged her eggs, she 
 scrapes off the long downy hairs of the tail-tuft, and arranges 
 them carefully on the eggs so as to cover them with a conical 
 thatch, very much resembling that of an ordinary corn-rick. 
 
 The Brown-tailed Moth acts in a similar fashion. 
 
 Furs of various kinds act in the same manner, being imper- 
 vious to wet during the life of the animal. Such, for example, 
 is the fur of the Beaver, that of the Capybara, and that of 
 the Seal, which are animals living in our time. These, how- 
 ever, are exceeded in their thatch-like powers by the three 
 successive coatings of hair that were worn by the ancient 
 Mammoth, the outermost being very long and very coarse, and 
 hanging down in heavy tufts so as to shoot the water from 
 them.
 
 TILED ROOFS. 
 
 187 
 
 BEING on the subject of roofs, we will take a few more 
 examples of the roof as anticipated in Nature. 
 
 That parallel fibres, whether animal or vegetable, can throw 
 off rain when properly arranged, has already been shown. 
 Much more is it evident that flat or partly flat plates will have 
 
 WINGS OF BUTTERFLY. 
 
 TILES OF HOUSES. 
 
 the same effect, if they be arranged so that the joints are 
 " broken," as masons and bricklayers say, i.e. so that the broad 
 part of the upper row of plates overlaps the junction of two 
 of the plates in the row immediately below it. 
 
 ON the right hand of the accompanying illustration are 
 given two sketches of a modern roof, one slated and the other 
 tiled. The figures on the left show that this formation has 
 been anticipated by Nature, in the wonderful system of scales 
 which cover the wings of butterflies and moths, and to which 
 all their brilliancy of colour is owing. In spite of their 
 minute size, most being too small to be distinguished by the 
 unaided eye, they are arranged as regularly as the best work- 
 man could lay the slates or tiles on a roof, and on exactly the 
 same principle. 
 
 The shapes of these scales vary in almost every species, but 
 they are always arranged on the same plan, namely, being 
 placed in successive rows, each overlapping the other. 
 
 In consequence, it is almost impossible to wet a butterfly's 
 wing with water. The insect may be plunged beneath the 
 surface, and the long hairs of the body will be soaked and cling 
 together in a very miserable fashion. But the water rolls off 
 the wings like rain off a slated roof, and even if a few drops 
 remain on the surface, they can be shaken off, and the wing 
 will be perfectly dry. 
 
 Mostly these scales are flat, but sometimes they are curved.
 
 188 NATURE'S TEACHINGS. 
 
 I have among my microscopic objects a piece of wing from 
 a South American butterfly, the scales of which are oblong and 
 bent, just like the curved tiles shown in the second right-hand 
 figure of the illustration. These beautiful scales are deep 
 azure or warm brown, according to the direction of the 
 light. 
 
 Perhaps my readers may call to mind that some architects 
 dislike the flat, square form in which slates are usually put 
 on roofs, and try to make them less formal. 
 
 Sometimes they take their square slates, and fit them with 
 one of the angles uppermost, so that each slate looks something 
 like the ace of diamonds in a pack of cards. Sometimes they 
 are still more ambitious, and certainly succeed in producing a 
 
 SHELL OF TOBTOISE. HEXAGOXALLY TILED BOOK. 
 
 better effect, by cutting the slates in hexagons instead of 
 squares, and fixing them as shown in the right-hand figure of 
 the illustration. Putting aside the familiar hexagons of the 
 honeycomb, and the apparent hexagons of an insect's com- 
 pound eye, we have in the common Tortoise an example of 
 hexagonal plates that exactly resembles the slate roofing. 
 
 In the next illustration we have a variety of the same prin- 
 ciple exhibited in differently shaped tiles and scales. The 
 figures on the right hand show the pointed, the square, and the 
 oblong tiles. These also would answer very well as representa- 
 tions of different forms of scale armour, the one being intended 
 to throw off rain, and the other to repel weapons. 
 
 On the other side of the illustration are examples taken from 
 the animal kingdom. First comes the Bajjerkeit, or Short- 
 tailed Manis, which has already been mentioned, and whose 
 imbricated scales will resist the blows of any spear or sword. 
 As to my own specimen, when it is struck, it resounds as if it 
 were a solid plate of metal, and I should think that during the
 
 TILES AND SLATES. 
 
 189 
 
 lifetime of the animal a reasonably strong axe would not easily 
 make its way through that coat of mail. 
 
 Below the Manis are a pair of fish, whose scales, though not 
 so strong as those of the mammal, yet are arranged in the same 
 
 XLUJL 
 
 cox: 
 
 "MJltuJICH. 
 
 MANIS. FISHES. BANDS OP ARMADILLO. 
 
 TILES AND SLATES. 
 
 manner, and answer the same purpose. The last figure repre- 
 sents three scale-bands of the Armadillo, an animal which has 
 already been mentioned. I may as well state here that in 
 several anthropological museums there are various portions of 
 defensive armour made from the scale-clad skin of the Croco- 
 dile, Manis, and similar animals.
 
 ARCHITECTUEE. 
 
 CHAPTER III. 
 
 THE WINDOW. -GIRDERS, TIES, AND BUTTRESSES THE 
 TUNNEL. THE SUSPENSION-BRIDGE. 
 
 The Window, and its Modifications according to Climate. Bars and Tracery. 
 The Wheel-window and the Caddis. Curious Structure of the Caddis-tube. 
 Object of its Window. The Girder as applied to Architecture. The 
 Radius and Ulna. The Tie as applied to Architecture, and its Value. Com- 
 bination of the Tie and Girder. Structure of the Crystal Palace. Leaf of 
 the Victoria Regia. A Gardener turned Architect. The Buttress in Art 
 and Nature. The Tunnel used as a Passage of Communication. Natural 
 Tunnel of the Ship- worm. The Thames Tunnel. The Piddock, or Pholas. 
 The Driver-ant. The Suspension-bridge. The Palm-wine Maker and his 
 Bridge. Suspension-bridges of Borneo and Sout]| America. The Creepers 
 and the Monkey Tribes. The Spider and Little Ermine Caterpillar. 
 
 THE WINDOW. 
 
 TTAVINGr traced, though but superficially, the chief parts of 
 *-*- a building, such as the walls, the door which is opened 
 through the walls, and the roof which shelters them, we 
 naturally come to the Windows by which light is admitted to 
 them, and enemies excluded. 
 
 There are, perhaps, few points in Architecture in which such 
 changes have been made as in the Window, which, instead of 
 being a difficulty in the way of the architect, is now valued as 
 a means of increasing the beauty of the building. Taking for 
 example even such advanced specimens of Architecture as those 
 furnished by Egypt, Greece, and Rome, we find that the 
 Window is either absent altogether, its place being supplied by 
 a hole in the roof, or that, when it is present, it was made 
 quite subordinate to the pillars and similar ornaments of the 
 building. 
 
 This fact is, perhaps, greatly owing to the influence of climate. 
 In the parts of the world which have been mentioned in con-
 
 "WINDOWS. 
 
 191 
 
 nection with this subject, light and heat appear to be rather 
 enemies than friends, and the object of the architect was to 
 enable the inhabitants of his houses to avoid rather than to 
 welcome both. Consequently, the "Windows were comparatively 
 insignificant. They were not needed for the purposes of light 
 or air, those being generally furnished by the aperture in the 
 roof, and consequently were kept out of sight as much as 
 possible. 
 
 But when architects had to build for a sterner, a colder, and 
 a darker clime, where the sun never assumed that almost 
 devouring heat and light which in hot countries drive the 
 inhabitants to invent endless devices for obtaining coolness and 
 shade, a different style of Architecture sprang up. In this the 
 Window became nearly the most prominent part of the building : 
 the elements were excluded by glass instead of stone, and the 
 principal modifications of light were obtained by staining the 
 glass in various rich colours. Perhaps the Window has 
 attained its culminating point in the Crystal Palace, which is all 
 window except its foundations. 
 
 Partly in order to enable the glass to be inserted, and partly 
 to increase the beauty of the building, and to avoid the mean 
 appearance of Windows filled in with plain iron bars crossing 
 
 CADDIS GEATIMO. 
 
 WHEEL- WIXDOW. 
 
 each other at right angles, the interior of the Windows was 
 adorned with stone " tracery," varying much according to the 
 epoch of the building. 
 
 One of the most beautiful forms of the Window is that 
 which is called the Wheel. The window itself is circular, and 
 the tracery is disposed so as to bear an exact resemblance to an 
 ornamental wheel, the lines of the tracery running from the 
 circumference to the centre, just like the spokes of a wheel. 
 One of these Wheel-windows is shown on the right hand of the 
 illustration.
 
 192 NATURE'S TEACHINGS. 
 
 On the other side is an object, which at a hasty glance 
 might be taken for another Window of the same character. It 
 is, however, the work of an insect, and not of man, and is 
 magnified in order to show its structure better. 
 
 Any of my readers who may happen to be entomologists or 
 anglers, or both, are familiar with the Caddis- worm of our fresh 
 waters. Most of us know that the Caddis is the grub or larva 
 of the Stone-fly (Phryganea], an insect haunting the water- 
 side, and so moth-like in its general aspect that many persons 
 think that it is really a brown moth. The changes or meta- 
 morphoses of these insects are well worthy of notice. 
 
 In one respect the Caddis resembles the larva of the Wax- 
 moth, mentioned on page 151, inasmuch as it has a soft, defence- 
 less body, while the first three segments are comparatively 
 hard. Like the Wax-moth also, the Caddis lives in a tube 
 constructed by itself. Instead, however, of having a long and 
 fixed tube, up and down which it can pass at pleasure, the 
 Caddis makes a tube only a little longer than its body, and 
 light enough to be carried about, just as the hermit-crab carries 
 its supplementary shell. There are many species of Caddis-fly. 
 
 The Caddis inhabits fresh waters, and cares nothing whether 
 they be ponds or running streams. In order to defend its 
 white, plump, and helpless body from the fishes and other 
 enemies, it constructs a tube around its body, strengthening it 
 by a wonderful variety of material according to the locality. 
 
 Mostly the tubes are covered with little pieces of stick or 
 grass, or leaves, while some species use nothing but sand-grains, 
 constructing with them a tube very much resembling in shape 
 an elephant's tusk, and reminding the conchologist of the 
 dentalium shell. But they seem to use almost anything that 
 comes to hand. Taking only examples found by myself in a 
 single pond, these cases are formed of sand, stones, sticks, grass- 
 Btems, leaves, shells of small water-snails, mostly the flat 
 planorbis, the opercula of the water-snail, empty mussel-shells, 
 a chrysalis of some moth which had evidently been blown into the 
 water from an overhanging tree, and acorn-cups. The larva, 
 however, does not seem to be able to fasten together any objects 
 with smooth surfaces, and though it has been known, when in 
 captivity, to make its cases out of gold-dust or broken glass, it 
 could not use either material when in the form of beads.
 
 GIRDERS, TIES, AND BUTTRESSES. 193 
 
 When it is full-fed, and about to enter the pupal state, it 
 proceeds to prepare its habitation. As a larva, when it desired 
 to feed, it protruded its head and the front of its body from the 
 mouth of the tube, and then crawled about in search of nourish- 
 ment, dragging the tube with it, and holding it firmly by 
 means of the claspers with which the end of the body is fur- 
 nished. But when it becomes a pupa it is no longer able to 
 defend itself, and is instinctively compelled to secure its safety 
 in some peculiar manner. 
 
 It cannot fasten up the entrance entirely, because it would 
 not be able to breathe unless water could pass over its body. 
 
 L v 
 
 Accordingly, it constructs a grated window precisely like those 
 of the old castles, so that water can pass freely, while no enemy 
 can gain admittance. Unlike, however, the grated windows of 
 the castle, which had no pretence to beauty, the Caddis always 
 constructs its barriers in some definite pattern. Each species 
 appears to have its own peculiar pattern, but all agree in making 
 their window, if we may so call it, exactly like a wheel-windo\r 
 before the glass is inserted. 
 
 When the pupa is about to make its final change into the 
 perfect form, it cuts away the tracery with a pair of sharp 
 jaws, with which it is furnished for this sole purpose, emerges 
 from the water, throws off the pupa- skin, and issues forth as 
 a Stone-fly. 
 
 GIRDERS, TIES, AND BUTTRESSES. 
 
 NEXT in order come the means by which walls are supported 
 internally by Girders and Ties, and externally by Buttresses. 
 
 OF late years the Girder, in its many varieties, has come into 
 general use, especially in the construction of railway bridges 
 and similar edifices. 
 
 RADIUS AND ULNA OP HUMAN ABM. GIRDER (FROM A HOUSE IN BERHONDSKY). 
 
 On the right of the accompanying illustration is shown the 
 Girder in its simplest form. The figure was taken from a 
 Girder which is used in supporting the walls of a large 
 
 o
 
 194 NATURE'S TEACHINGS. 
 
 building in Bermondsey. Sometimes a transverse stay con- 
 nects the centres of the two curved beams ; but it is seldom 
 needed. 
 
 The reader will see that if the interval between the curved 
 beams were to be filled up, we should obtain a form very like 
 that of the engine beam described in page 25 ; while, if we 
 could imagine two such girders intersecting each other at right 
 angles throughout their length, a section of the two would 
 exactly resemble the section of the engine beam as given in 
 the uppermost figure in page 25. 
 
 IN the human body there are four admirable examples of 
 the natural Girder, namely, in the bones of the arms and legs. 
 
 On the left hand of the illustration are shown the two bones 
 of the fore-arm, technically named the " radius " and "ulna." 
 It will be seen that these bones are arranged on the principle 
 of the girder. In men who are especially powerful of grasp, 
 it has been noticed that the curve of the radius and ulna has 
 been exceptionally bold, while we have it developed to the 
 greatest extent in the fore- arm of the Gorilla, an animal whose 
 arms are simply gigantic. 
 
 The two bones of the legs, from the knee to the ankle, are 
 arranged in a similar manner, and are called the " tibia " and 
 " fibula." The last named signifies a brooch, and is given to 
 the bone because it is very slender, nearly straight, and when 
 in its place bears no small resemblance to the pin of the fibula, 
 or ancient Roman brooch. 
 
 Nature, however, has exceeded Art in her girder. Those of 
 man's manufacture can only exert their strength in one direc- 
 tion, and would be of little use if force were to be applied to 
 them in any other direction. Those of the human body, how- 
 ever, have the capability of partial revolution on each other at 
 their points of junction, thus enabling the Girder to apportion 
 its strength according to the direction of the resistance which 
 it has to overcome. 
 
 WE now come to the Ties, i.e. those internal beams, whether 
 of metal, wood, stone, or brick, which prevent walls from falling 
 outwards. There is no danger of the walls falling inward, but 
 there is very great danger of their falling outward, especially
 
 ORIGIN OF THE CRYSTAL PALACE. 195 
 
 when the weight or "thrust" of the roof tends to force them 
 apart. 
 
 In some buildings, such as an old country church which I 
 attended for many years, the architect had openly acknow- 
 ledged the tendency of the walls to fall outward, and had 
 counteracted it by a series of great beams extending com- 
 pletely across the nave and aisle. As he had not even troubled 
 himself to hide their office, so he did not trouble himself to 
 conceal the fact that they were tree-trunks, but left them 
 roughly squared with the axe, lest, if he had squared them 
 throughout their length, he should have diminished their 
 strength. 
 
 The effect of the partially squared beam is, of course, far 
 more picturesque than that of a completely squared one. The 
 architect, however, need not have been so careful about strength, 
 for if the beams had been only half their diameter they would 
 have been just as effective. The strain on them is by pulling, 
 and not by pushing. Now, as any one can see by trying the 
 experiment with a splinter of wood say a lucifer-match an 
 enormous power is required to break it by tearing the ends 
 asunder, while it can be easily broken by pushing them towards 
 each other. 
 
 But for this power of resistance, we should never have had 
 our Crystal Palace. That apparently intricate, but really 
 simple (and the more beautiful for its simplicity), intersection 
 of beams and lines diminishing in the distance to the thick- 
 ness of spiders' webs, is nothing more than a combination of 
 the Girder and Tie, the two together combining lightness and 
 strength in a marvellous manner. 
 
 The story of the Crystal Palace is now so well known that it 
 need not be repeated in detail. A vast building was required for 
 the Exhibition of 1851, and not an architect was able to supply 
 a plan which did not exhibit some defect which would make 
 the building almost useless. 
 
 Suddenly a Mr. Paxton, who was a gardener, and not an 
 architect, produced (on a sheet of blotting-paper) a rough plan 
 of a building on a totally new principle, and not only fulfilling 
 all the requisite conditions, but being capable of extension in 
 any direction and to any amount. There have been very few 
 bolder conceptions than that of making iron and glass take the 
 
 o 2
 
 196 NATURE'S TEACHINGS. 
 
 place of brick, stone, and timber, and the result fully justified 
 the expectations even of the inventor. 
 
 How a gardener suddenly developed into an architect remains 
 to be seen ; and, indeed, in this case the architecture was 
 the result of the gardening, or rather, of practical botany 
 applied to art. Some years before the invention of the Crystal 
 Palace, that magnificent plant, the Victoria Regia, had been 
 introduced into England. Its enormous leaves, with their 
 wonderful power of flotation, caused a great stir at the time, 
 and some of my readers may remember a sketch which was 
 engraved in the Illustrated London News, and which repre- 
 sented a little girl standing on one of these leaves as it floated 
 on the water. 
 
 LEAF OF VICTORIA REGIA (REVERSED). CRYSTAL PALACE. 
 
 Mr. Paxton saw how this power was obtained, and the result 
 was that he copied in iron the lines of the vegetable cellular 
 structure which gave such strength to the Victoria Regia leaf, 
 and became more eminent as an architect than he had been as 
 a gardener. The capabilities of the Crystal Palace had lain 
 latent for centuries, but the generalising eye of genius was 
 needed to detect it. A thousand men might have seen the 
 Victoria Regia leaf, and not thought very much of it ; but the 
 right man came at the right time, the most wonderful build- 
 ing in the world sprang up like the creation of a fairy dream, 
 and the obscure gardener became Sir Joseph Paxton. 
 
 I have no doubt that thousands of similar revelations are at 
 present hidden in Nature, awaiting the eye of their revealer. 
 
 Now we come to the principle of the Buttress, i.e. giving 
 support to the exterior, instead of the interior, and strengthen- 
 ing the walls by pushing them together, instead of pulling 
 them together.
 
 THE BUTTRESS. 
 
 197 
 
 Putting aside the " flying " buttress, which is simply one 
 buttress mounted on another to support the clerestory walls, 
 the structure of the ordinary buttress is simple enough. 
 
 The most primitive form of the buttress is often found in 
 country farms, where the farmer sees the walls of his barns and 
 outhouses leaning suspiciously on one side, and, instead of 
 going to the root of things, props them up by a stout pole or 
 beam. 
 
 This, however, can be nothing but a temporary arrangement, 
 especially as beams have a tendency to rot, and their ends to 
 sink into the earth by the gradual pressure of the wall. The 
 genuine buttress was therefore evolved, the basal part being 
 very thick and heavy, and the upper part comparatively thin 
 and slight. Simple as a buttress looks, much skill is needed in 
 making it, and if it be not rightly built?, it does infinitely more 
 harm than good. 
 
 A case in point occurs within a short distance of my house. 
 The walls of an ancient edifice having shown symptoms of 
 yielding, and some ominous cracks made their appearance, a 
 couple of very sturdy buttresses had been erected, in order to 
 stop further damage. Unfortunately, the builder was ignorant 
 
 PADDLE-WOOD TREE. 
 
 BUTTRESSES. 
 
 of the principles of architecture, and though he made the 
 buttresses very strong and massive, he omitted to make a solid 
 foundation on which their bases should rest. Consequently he 
 only hung the buttresses, so to speak, on the Tvall, and helped 
 to tear it asunder by the additional weight.
 
 198 NATURE'S TEACHINGS. 
 
 NATURE, as well as Art, supplies her buttresses. In our own 
 country we find the natural buttress more or less developed 
 in our trees, as it is wanted. 
 
 Take, for example, any plantation, and examine the trees. 
 It will be found that those in the centre, which are sheltered 
 on all sides from the force of the wind, shoot up straight 
 towards the light, have comparatively slight and slender stems, 
 and occasionally display such energy in forcing themselves 
 upwards, that when two branches find that there is not room 
 for both, they form a sort of alliance, fuse themselves together, 
 and force their united way towards the sky. 
 
 Take, however, the trees in the outside rows of the planta- 
 tion, and see how they throw out their straight roots and 
 branches towards the outside, and how, on the inside, their 
 trunks are as smooth and their roots as little visible as those of 
 the trees that grow in the centre of the plantation. 
 
 Almost any tree will develop itself in this fashion, showing 
 that instinct can rule the vegetable as well as the animal 
 world. 
 
 There is, however, a South American tree .which far sur- 
 passes any of our trees in its power of throwing out spurs or 
 buttresses, principally, I presume, because it may have to 
 endure the fiercest storms from any quarter and at any time. 
 So bold are these projections that several men would be hidden 
 if standing between two of them, and so numerous are they 
 that if a section of the tree were taken at the base of the 
 ground, it would resemble a conventional star or asterisk, *, 
 rather than an ordinary tree-trunk, O- 
 
 The scientific name of this curious tree is Aspidomorpha 
 excekum. 
 
 The natural buttresses are so thin and so wide that they 
 look like large planks set on end, with one edge against the 
 tree. Indeed, they are used as planks, nothing more being 
 required than to cut them from the tree. 
 
 This is very easy, as, while the wood is green, it is so soft 
 that a blow from a " machete," or native cutlass, is sufficient to 
 separate it. With the same instrument the native makes these 
 flat planks into paddles for his canoe, the soft wood yielding 
 readily even to the imperfect edge of the rude tool. When 
 the wood dries, it becomes very hard, light, and singularly
 
 THE TUNNEL. 
 
 199 
 
 elastic, all these properties qualifying it for its object. I have 
 several of these paddles in my collection. They are much 
 prized by the natives, and are always stained in various 
 patterns with red and black dyes. 
 
 In consequence of the use which is made of this tree, it goes 
 by the popular name of " paddle-wood." 
 
 THE TUNNEL USED AS A PASSAGE. 
 
 As to this division of the subject, I have not been quite sure 
 where it should be placed, but think the present position a 
 tolerably appropriate one. 
 
 We have already, in the igloo of the Esquimaux and the 
 winter dwelling of the seal, found examples of the Tunnel 
 
 TUNNEL OF ANOMMA. 
 
 PHOLAS. 
 
 SHIP-WORM. 
 
 KAIL WAY TCJTNEL. 
 
 when used as an appendage to the houses and a means of 
 security. We now come to the Tunnel as affording the means 
 of locomotion. 
 
 Take, for example, our own railway system. Had it not 
 been for the power of tunnelling, the railway would have lost 
 nearly its whole value, for it would have been restricted to local 
 districts, and could not have penetrated, as it now does, to all 
 parts of the country, without reference to hill, dale, or level 
 ground. Our present system of engineering has wonderfully 
 developed the capability of tunnelling. In former times it was
 
 200 NATURE'S TEACHING?. 
 
 thought a most wonderful feat to drive a tunnel under the 
 Thames, while in these days the tunnel through Mont Cenis 
 has been completed, and we are hoping to make a submarine 
 tunnel from England to France. 
 
 IN Nature we can find many examples of Tunnels used for 
 similar purposes. The silken tunnel of the Wax-moth larva 
 has already been mentioned, and we now come to Tunnels 
 where earth in some form, and not silk, is the material of which 
 they are constructed. 
 
 The lowermost figure on the left-hand side of the illustration 
 represents that well-known and most destructive burrower, the 
 Ship- worm (Teredo], which, by the way, in spite of its popular 
 name, is not a worm, but a mollusc. This creature has a pecu- 
 liar interest for engineering, inasmuch as its mode of working 
 gave Brunei the first idea of subaquatic tunnelling in loose, 
 sandy soil, just as the Victoria Regia leaf gave to Paxton the 
 idea \vhich afterwards developed into the Crystal Palace. 
 
 The plan adopted by the Ship- worm is at the same time 
 simple and effective. It feeds upon wood, and gradually eats 
 its way through almost any timber that may be submerged. It 
 does not, however, merely bore its way through the timber, but 
 lines its burrow with a coating of hard, shelly material. Taking 
 this hint, Brunei proceeded in the same fashion to drive his 
 tunnel through the very ungrateful soils which form the bed of 
 the Thames. 
 
 Ho built a "shield," as he called it, of iron, exactly fitting 
 the tunnel, and divided into a number of compartments, each 
 of which could be pushed forwards independently of the others. 
 In each compartment was a single workman, and, as he 
 excavated the earth in front of him, he pushed forward his 
 portion of the shield, while the interior was cased with brick- 
 work, just as a Teredo tunnel is cased with shell. 
 
 ABOVE the Teredo is represented another marine tunnel- 
 maker, as it appears in its burrow. 
 
 This is the mollusc popularly known as the Piddock, and 
 scientifically as Pholas dactylm. It may be found abundantly 
 in all our chalk cliffs, boring its tunnels deeply into the stone, 
 and aiding the sea in its slow, but never-ending task of
 
 THE DRIVER-ANT. 201 
 
 breaking down the cliffs on one side, while it gradually rears 
 them up on another. As the material into which the Piddock 
 burrows is so hard, there is no need for lining the tunnel, as is 
 done by the Teredo. In this point, too, our engineers follow its 
 example. "When their tunnels pass through comparatively 
 soft ground, they line it with masonry, proportioning the 
 thickness of the lining to the looseness of the soil. But, when 
 they come to solid rock, they are content with its strength, 
 and do not trouble themselves about the lining. 
 
 The mode of action adopted by the Pholas has long been a 
 disputed point, and even now appears to be not quite settled. 
 I think, however, that William Robertson has proved by his 
 experiments that the shell and the siphon are both brought into 
 requisition. The shell perpetually rotates in one direction, and 
 then back again, just like the action of a bradawl, and, by the 
 file-like projections on its surface, rasps away the chalk, convert- 
 ing it into a fine powder. This powder, being of course mixed 
 with water, passes into the interior of the animal, and is ejected 
 through the siphon. 
 
 There are many species of Pholas which burrow into 
 various substances, even in floating cakes of wax and resin. 
 The same species, too, will burrow into different substances, and 
 it is worthy of notice that those specimens which burrow into 
 soft ground attain a much larger size, and their shells are in 
 better preservation, than those which force their way through 
 hard rock. 
 
 THE uppermost figure represents a very remarkable tunnel, 
 having the peculiarity of feeing built instead of sunk. It is the 
 work of an African Ant belonging to the genus Anomma, and 
 popularly known as the Driver-ant, because it drives away 
 every living creature which comes across its course of march. 
 
 There are many Ants which seem to rejoice in the full blaze 
 of the tropical sun, running about with ease on rocks which 
 would scorch and raise blisters on the hand if laid on it, and 
 finding no difficulty in obtaining the moisture needful for the 
 mud walls of their habitations. But the Driver-ants cannot 
 endure the sun, and, unless compelled by necessity, will not 
 march except at night, or at all events during cloudy days. 
 Should, however, they be absolutely forced to march in the sun-
 
 202 NATURE'S TEACHINGS. 
 
 shine, they construct as they go on a slight gallery, which looks 
 very much like the lining of a tunnel stripped of the surround- 
 ing earth. If their path should lead them to thick herhage, 
 sticks, &c., which form a protection from the sun, the Driver- 
 ants do not trouble themselves to make a tunnel, but take 
 advantage of the shade, and only resume the tunnel when they 
 reach the open ground. 
 
 Sometimes, when they are on a marauding expedition, they 
 construct a tunnel in a very curious manner, their own bodies 
 supplying the materials. The reader must know that there are 
 several classes of these insects, varying in size from that of a huge 
 earwig to that of the little red ant of our gardens. The largest 
 class seem to care little about the sunshine, the protection 
 being mostly needed by the workers. The following is 
 Dr. Savage's account of their proceedings: 
 
 "In cloudy days, when on their predatory excursions, or 
 migrating, an arch for the protection of the workers is con- 
 structed of the bodies of their largest class. Their widely 
 extended jaws, long, slender limbs, and projecting antennae, 
 intertwining, form a sort of network that seems to answer well 
 their object. 
 
 " Whenever an alarm is given, the arch is instantly broken, 
 and the Ants, joining others of the same class on the outside of 
 the line, who seem to be acting as commanders, guides, and 
 beauts, run about in a furious manner in pursuit of the enemy. 
 If the alarm should prove to be without foundation, the victory 
 won, or danger passed, the arch is quickly renewed, and the 
 main column marches forward as before, in all the order of an 
 intellectual military discipline." 
 
 How they should be able to direct their course, and to chase 
 an enemy, is not easy to understand ; for, as far as is known, 
 they are absolutely blind, not even an indication of an eye 
 being seen. 
 
 THE SUSPENSION-BRIDGE. 
 
 THE mention of these Ants brings us to another point in 
 architecture. We have already seen that they can not only 
 build arched tunnels, but also can form their own bodies into 
 arches, and we shall presently see how they can form them- 
 selves into Suspension-bridges. We will, however, first take
 
 THE SUSPENSION-BRIDGE. 
 
 203 
 
 the Suspension-bridge, and its vegetable origin, before passing 
 to the animal. 
 
 I have little if any doubt that the modern Suspension- 
 bridge, with all its complicated mathematical proportions, was 
 originally suggested by the creepers of tropical climates. There 
 are few points in a tropical forest, no matter in what part of 
 
 CEEEPEP.S. 
 
 SUSPENSION-BRIDGE. 
 
 the world, more striking than the wonderful development of the 
 creeping plants. The trees are very much like those of our own 
 forests, and are in no way remarkable, but the creeping plants 
 form the chief feature of the woods. 
 
 They extend themselves to unknown lengths, crawling up to 
 the very summit of a lofty tree, hanging down to the very 
 ground, if not caught by a midway branch, running along the 
 earth, making their way up another tree, and so on ad infinitum. 
 They interlace with each other, forming almost impenetrable 
 thickets, as has already been mentioned while treating of Nets, 
 and there is scarcely a tree that is not connected with its 
 neighbour by means of these wonderful creeping plants. 
 
 Of course the monkey tribes make great use of them in pass- 
 ing from one tree to another, thus being able to avoid the 
 ground, which is never to a monkey's liking. Man, therefore, 
 copies the example of the monkey, and makes use, either of the 
 creepers themselves, or of ropes stretched from tree to tree in 
 imitation of them. 
 
 In some parts of the world, where palm wine, or " toddy," is
 
 201 NATURE'S TEACHINGS. 
 
 manufactured, the native has recourse to an ingenious device 
 which saves a vast amount of exertion. As the calabash which 
 receives the juice of the palm-tree is always fixed at a consider- 
 able height, and as each tree only yields a limited supply, the 
 toddy-maker would be obliged to ascend and descend a great 
 number of trees before he could collect his supply of palm- 
 juice. 
 
 In order to save himself trouble, he has the ingenuity to con- 
 nect the trees with each other by two ropes, the one about six 
 feet above the other. He then has only to ascend once, and 
 descend once, for he ascends one tree, and by means of the 
 ropes passes from tree to tree without needing to descend. 
 
 The mode of traversing these ropes is simple enough, the 
 lower rope serving as a bridge, along which the man walks, 
 and the upper rope being held by the hands. Those who see 
 these palm- wine makers for the first time are always greatly 
 struck. At some little distance the ropes are quite invisible, 
 and the man appears to be walking through the air without any 
 support whatever. 
 
 In Borneo the Rattan is continually put in requisition as a 
 bridge. It runs to almost any length, a hundred feet more or 
 less being of little consequence ; it is lithe and 'pliant, and so 
 strong that it can hardly be broken. The " canes " formerly 
 so much in vogue among schoolmasters, and now so generally 
 repudiated, are all cut from the Rattan. Chiefly by means of 
 this natural rope, the Dyak of Borneo flings his rude suspen- 
 sion-bridges across chasms or rivers, and really displays a 
 wonderful amount of ingenuity in doing so. 
 
 The one fault of these bridges is their tendency to decay, or 
 perhaps to be eaten by the multitudinous wood-eating insects 
 which swarm in that country. However, the materials cost 
 nothing at all, and time scarcely more, so that when a bridge 
 breaks down, any man can fit up another at the expense of a few 
 hours' work. As, moreover, the Dyaks have a curious way of 
 building their houses on one side of a ravine, they find that 
 a bridge of this kind saves them the trouble of descending 
 and ascending the ravine whenever they wish to visit their 
 house. 
 
 In many parts of America the Suspension-bridge is almost 
 a necessity. The country is broken up by vast clefts, tech-
 
 EXTEMPORISED SUSPENSION-BRIDGE. 205 
 
 nically called "canons." These canons are ravines in the rocky 
 ground, with sides almost perpendicular. For the greater 
 part of the year they are dry, but sometimes, and without 
 the least warning, they become the beds of roaring torrents, 
 rising to some thirty or forty feet in height, and carrying away 
 everything before them. 
 
 Over these ravines are thrown suspension-bridges made 
 almost entirely of creepers, and loosely floored with rough 
 planks. Although they are very strong, they appear to be 
 very fragile, and even under the tread of a human being 
 swing and sway about in a manner that always shakes the 
 nerves of one who is unaccustomed to them. Yet, even the 
 mules of the country can cross them, the animals picking their 
 way with the wonderful sure-footedness of their kind, and 
 not in the least affected by the swaying of the bridge. 
 
 Passing from the vegetable to the animal world, we revert 
 to the Driver-ants, which have already been mentioned. It 
 has been seen that their soldier-ants can, with their own 
 bodies, form a tunnel, under the shade of which the workers 
 can pass, and we have now to see how they can, with the same 
 materials, form a suspension-bridge. 
 
 It often happens that on their march they come to water, 
 and, as they always advance with total disregard of difficulties, 
 they must needs invent some very ingenious way of overcoming 
 the difficulty. One of them climbs a branch which overhangs 
 the water, clasps the undermost twig very tightly, and allows 
 itself to hang from it. Another at once follows, and suspends 
 itself from its comrade in like manner, the powerful and sickle- 
 like jaws doing their duty as well as the legs. A chain of Ants 
 is thus speedily formed. When the lowermost Ant touches 
 the water, it merely spreads all its legs, and awaits the develop- 
 ment of events. Another runs over it, holds to the first Ant 
 by its hind-legs, and stands in the water, spreading its limbs 
 as much as possible over the surface. Ant after Ant descends, 
 until quite a long chain of the insects is formed, and is swept 
 downwards with the stream. By slow degrees the chain is 
 lengthened, until the Ants at its head are able to seize the 
 bank on the opposite side of the water. When they have suc- 
 ceeded in doing so, the bridge is complete, and over that living 
 bridge will pour a whole army of Driver-ants.
 
 206 NATURE'S TEACHINGS. 
 
 Even in those cases where this mode of travelling would be 
 too perilous on account of the rapid torrent, the Ants contrive 
 to suspend themselves in long strings until they effect a com- 
 munication with the trees of the opposite bank. 
 
 It is, perhaps, needless to give more than a passing reference 
 to the Suspension-bridges made by Spiders, by means of which 
 they can traverse considerable distances. The similar bridge 
 of the Little Ermine Caterpillar has already been mentioned, 
 when treating of the subject of Double Walls.
 
 ARCHITECTURE. 
 
 CHAPTER IY. 
 
 LIGHTHOUSES. THE DOVETAIL. THE DAM. SUBTERRANEAN 
 DWELLINGS. THE PYRAMID. MORTAR, PAINT, AND VAR- 
 NISH. 
 
 The Eddystone Lighthouse : its Position, and the Difficulties of building it. 
 Destruction of successive Lighthouses. Smeaton's Idea of Form borrowed 
 from the Tree-trunk. Mode of building. Rooting it into the Rock. 
 Principle of the Dovetail. Bones of the Human Skull, and their Articula- 
 tion. The Dam, and its Uses to Man. The Lock and the Water-mill. 
 Dam of the Beaver : its Objects and Mode of Construction. Popular Errors 
 with regard to the Dam. Subterranean Dwellings. The Indian Palace, 
 and its Use in Summer. Subterranean Dwellings in Kamschatka, and their 
 Use in Winter. The Wood or Horse Ant, and its double Dwelling. The 
 upper and lower Nests used according to the Amount of Warmth required. 
 Section of the Nest, and a Glimpse into its Interior. The Pyramid. 
 Derivation of its Name. Natural Objects from which the Form was derivsd. 
 Subaquatic Mortar or Cement, and its Use to Man. Subaquatic Cement 
 used by the Caddis, the Stickleback, the Terebella, the Sabella, the Serpula, 
 and others. Paint and Varnish, and their Utility to Man. Propolis aa 
 used by the Hive Bee, and the Source whence it is obtained. 
 
 WE now come to some points in Architecture which cannot 
 well be grouped together, and must therefore be treated 
 as Miscellanea. 
 
 Our first example is one which was avowedly based upon 
 an imitation of Nature, namely, the celebrated Eddystone 
 Lighthouse, and we shall see that in two points first its form, 
 and next the mode in which the stones were fixed together 
 Nature had been closely followed by the architect. 
 
 Unlike ordinary lighthouses, this edifice had to be con- 
 structed so as to endure the full force of waves as well as wind. 
 A few miles from the southern coasts of Devon and Cornwall 
 there is a rock which in former times greatly endangered the 
 ships which passed along the Channel. Several attempts were 
 made to build a lighthouse on this dangerous spot. Winstan- 
 ley's lighthouse, which was finished in 1700, was wholly swept
 
 208 
 
 NATURE S TEACHINGS. 
 
 away three years later, together with the architect himself, 
 and some workmen who were engaged in repairs. So terrific 
 is the force of the elements on this spot, that the lighthouse 
 was entirely destroyed, and the only vestiges of it that were 
 ever discovered were some iron bars and a piece of chain. 
 
 Another lighthouse was built a few years afterwards, but 
 was burned down, it being of wood instead of stone. At last 
 the work was put into the hands of Smeaton, who saw that he 
 must build on a totally new plan. He took for his model the 
 
 TREE-TRUNK. 
 
 EDDYSTOXE LIGHTHOUSE. 
 
 trunk of a tree, and determined to build his lighthouse of the 
 same form as the tree-trunk, and to fasten it into the rock just 
 as a tree is fastened by its roots. Accordingly, he struck out 
 a new principle in the construction of such edifices, and his 
 model has been followed ever since. The reader will see, by a 
 glance at the illustration, how close is the resemblance in 
 external form. I may mention that the tree in question was 
 sketched from one in a paddock opposite my house. 
 
 Having settled the form of the lighthouse, and made it like 
 a tree-trunk, the next business was to fix it firmly in the rock, 
 and, in fact, to give it roots of stane. For this purpose, he 
 made the base of the edifice as wide as the rock would allow, so 
 as to correspond with the wide base of a tree-trunk, and traced
 
 DOVETAILING. 209 
 
 a circle of about ninety feet in circumference. Instead, how- 
 ever, of merely laying the stones as is usually done, or even 
 letting them into holes cut in the rock, he hit upon a singularly 
 ingenious device, whereby the building was practically a single 
 stone. 
 
 Instead of cutting the stones square or oblong, as is usually 
 done, he had them made so as to " dovetail " into each other, 
 much after the fashion of a child's puzzle toy, or the junctions 
 at the edge of a box. Thus, each stone fitted into those around 
 it, while the lowest tier was dovetailed in similar fashion into 
 the rock. 
 
 The stone employed was that which is called Moorstone, a 
 very hard variety of granite. Each course of stones was care- 
 fully fitted together on shore, and their accuracy tested, and 
 
 8CTUBES OP SKULL. SECTION OP DOVETAILED BOX. 
 
 EDDYSTONE LIGHTHOUSE. 
 
 they were then taken to the Eddystone rock, and fixed in their 
 places. Beside using these precautions, Smeaton fixed the 
 stones in their place with the strongest cement, and further- 
 more fastened the stones together and united the several courses 
 by strong oak treenails and iron clamps. As none of the stones 
 weighed less than a ton, and some of them were double that 
 weight, the strength of such an edifice may be imagined. 
 
 The accompanying illustration shows the arrangement of 
 these dovetailed stones in one of the courses. It will be seen 
 that the central stone must be laid first, and then the others 
 arranged round it. The whole edifice is rather more than 
 eighty-five feet in height, so that the elements have every 
 chance of demolishing it, as they did that of Winstanley. 
 More than a hundred years have now passed since it was built, 
 
 p
 
 210 NATURE'S TEACHINGS. 
 
 and, although the fury of the tempest has been such that the 
 waves have washed completely over its summit, it stands as 
 firmly as it did when it was finished in 1760. 
 
 WHETHER the original inventor of the " dovetail " took his 
 idea from Nature I cannot say, but he certainly might have 
 done so. On the left of the illustration is part of a human 
 skull. 
 
 The skull is not, as many persons seem to think, made of a 
 single bone, but it is composed of many bones, united by 
 " sutures," which are, in fact, natural dovetails. Although in 
 early life these sutures are comparatively loose, they hold the 
 various parts together so firmly, that if the head be violently 
 struck, the bones may break, but the sutures do not give 
 way. 
 
 Perhaps some of my readers may ask how it is possible to 
 take a skull to pieces witnout cutting it or fracturing the 
 su ures. It is done in a way equally simple and ingenious. 
 The skull is filled through the opening with dried peas, and 
 then sunk under water. The peas expand with the moisture, 
 and, as they exert an equable force in all directions, they 
 slowly and quietly pull the sutures asunder, without injuring 
 the bones. 
 
 THE DAM. 
 
 IN many human operations, where a certain depth of water 
 *s required in a running stream, the reasoning powers of man 
 have enabled him to attain his object by building a dam, or 
 obstacle across the stream, which forces the water to rise to its 
 level before it can find a passage. Such, for example, are the 
 Locks which render rivers navigable, and allow even the 
 heavily laden barges to traverse miles of water which would 
 otherwise have been closed to them. 
 
 Those mills, again, which are worked by water need that a 
 sufficient amount of water should be ready in order that it may 
 by its weight force the wheel round. Such a Dam is shown on 
 the right hand of the illustration, the height to which it raises 
 the water being shown by the level of the stream below the 
 Dam, and that of the water as it tumbles over in a miniature 
 cascade.
 
 THE DAM. 
 
 211 
 
 PUTTING aside the natural dams made by accumulations of the 
 various debris that are washed down by a swollen stream, and 
 which sometimes raise the water to a very great height, we 
 have an example of a natural dam in the curious structure 
 made by the Beaver, for the same purpose as that of the lock in 
 the mill-stream, namely, to insure a depth of water sufficient 
 for the needs of the beings that make them. 
 
 Every one has heard of the Beaver's dam, but there is so 
 much misconception on the subject, that a few words will not 
 be out of place. 
 
 Ingenious as is the animal in the construction of its dam, it 
 is not nearly so accomplished an architect as was once supposed. 
 We were told in the earlier books of Natural History that the 
 Beaver felled trees, cut off their branches into convenient lengths, 
 
 DAM MADE 13Y BE AVER. 
 
 DAM MADE BY MAN. 
 
 and sharpened one end, like an ordinary stake. Then they were 
 said to drive the sharp end of the stakes into the bed of 
 the river, to set them side by side, to interweave smaller 
 branches among them, and lastly, to fill up the interstices with 
 mud, leaves, and similar materials. In fact, they were supposed 
 to build a " wattle-and-daub " wall, like that which is in use at 
 the present day in Southern Africa. 
 
 The Beaver does nothing of the kind. It needs a dam, and 
 it makes one which is far stronger than the wattle-and-daub 
 could be. It begins by felling a tree, and letting it lie across the 
 stream, in some place where the banks are high and tolerably 
 steep. A bend of the river is usually chosen for the new dam. 
 Should not the tree be long enough for the Beaver's purpose, 
 two trees are felled, one on either side, so that their branches 
 meet in the middle. 
 
 p 2
 
 NATURE'S TEACHINGS. 
 
 These branches, and not any supposed stakes, are really the 
 upright supports of the dam. The trees being thus laid, the 
 Beaver cuts down branches from four to six feet in length, and 
 lays them horizontally among the boughs of the fallen trees. 
 Having thus made the foundations, so to speak, of its dam, the 
 Beaver then proceeds to fill in the spaces with roots, grass- 
 tufts, leaves, mud, and, indeed, almost anything on which it 
 can lay its paws. 
 
 After this, the Beaver has to take but little trouble, for the 
 stream itself becomes a silent, slow, but constant labourer, 
 lodging floating debris against the dam, and making a sloping 
 bank which much adds to its strength, By degrees, seeds that 
 lodge on the dam spring into life, and their roots act like 
 chains, binding the materials more closely together. Willow 
 twigs too, if they lodge on the dam and be left undisturbed, are 
 sure to " strike," as the gardeners say, and further to bind the 
 structure together. 
 
 It is evident, from this short description, that the lower part 
 of the dam is more solid than the upper. -In fact, the floods 
 are tolerably sure to wash away some eight or ten inches of the 
 upper part every year, and the Beavers have to make it afresh. 
 The height of these dams is not nearly so great as is generally 
 supposed. Mr. Green, a practical trapper, states that the 
 highest which he ever saw was only four feet six inches in 
 height, and that the average is under three feet. 
 
 The house of the Beaver is made on the same principle as 
 the dams. Every one knows that when sticks have been in the 
 water for any length of time, they become saturated and sink. 
 These sticks are chosen by the Beaver as the material for its 
 house, and are laid horizontally in the water, the heaviest 
 being reserved for the roof, so as to make it strong enough to 
 ward off the attacks of predacious animals. As with the dam, 
 mud, leaves, &c., are used to consolidate the edifice, but no 
 mud can be seen from the outside, the animal always finishing 
 off with a number of heavy logs laid on the roof. 
 
 SUBTERRANEAN DWELLINGS. 
 
 I DO not intend in this place to take up the whole subject of 
 Subterranean Dwellings, but only to point out cases where the 
 use of the Subterranean Dwelling depends on the climate of
 
 SUBTERRANEAN DWELLINGS. 
 
 213 
 
 the locality and the time of year, it being sometimes used and 
 sometimes neglected, sometimes inhabited for the sake of 
 warmth, and sometimes for that of coolness. 
 
 In various parts of India there are some most remarkable 
 Subterranean Dwellings. They are more than mere dwellings, 
 and are, in fact, magnificent palaces, sunk so deeply in the 
 earth that very little more than their roofs appear aboveground. 
 "When, however, a visitor descends the stairs that lead to the 
 interior of the palace, he finds it spacious, and with tiers of 
 chambers one below the other, very much like the wasp-nest 
 which has already been described. Nussur-ed-deen, the 
 second King of Oude, had several of these palaces, but very 
 seldom visited them, he having endeavoured to Europeanise 
 himself as much as possible, and to cast off his native customs. 
 
 SUBTERRANEAN AXTS NEST. 
 
 SUBTERRANEAN HOUSE OF KASISCHATKA. 
 
 He used occasionally to visit them, but it was only out of 
 etiquette, and he never really lived in them. 
 
 However much he might have rejected the ancient customs, 
 it is evident that in this case, at least, he was punishing 
 himself in rejecting these summer dwellings, which are always 
 cool, and where, if one set of apartments is too warm, nothing 
 is easier than to descend to the next. 
 
 THIS dwelling is made for the sake of coolness in summer. 
 Another subterranean dwelling is made for warmth in winter, 
 the non-conducting properties of the earth being in both cases 
 brought into play. This is the winter dwelling of the inha- 
 bitants of Kamschatka. 
 
 During the summer-time the Kamschatdales live in compara-
 
 214 NATURE'S TEACHINGS. 
 
 tively slight huts mounted on poles, and having the floor some 
 ten feet from the ground. 
 
 During the winter, however, they live in habitations of a 
 very different character. 
 
 In order to make these houses, they begin by digging a large 
 hole in the ground, about nine or ten feet in depth. This 
 they line with poles and sticks, making, in fact, a wall as of a 
 house. A stout conical roof is then raised over the hole, and 
 upon the roof earth is thickly strewn and beaten down, just as 
 has been mentioned when treating of the ice-house. The only 
 access to this strange house is by a circular aperture in the 
 centre of the conical roof, serving at once the purpose of a 
 door, a chimney, and a window. A notched pole answers as a 
 ladder, a low wooden dais placed against the wall serves as a 
 bed or a chair, for there is no other, and a few stones placed 
 together act as a fireplace. 
 
 IN looking at both these subterranean dwellings, I could not 
 but be reminded of a very common insect which has a double 
 dwelling, one moiety being aboveground, and the other moiety 
 below it. This is the common Wood-ant (Formica nifd), 
 whose large, leafy hills are so plentiful in some of our woods. 
 On account of its size, this species is sometimes called the 
 Horse-ant. 
 
 At first sight the nest looks something like a small 
 haycock, made entirely of chopped grass. When examined 
 * more nearly, it will be found to consist mostly of grass-stems, 
 little bits of stick, and leaves. Those of the fir are in great 
 request, for when they are dry they are very light, and their 
 form enables the Ant to interweave them with each other, so as 
 to form the necessary tunnels and galleries which line the 
 interior of the nest. The materials seem most unpromising, 
 but they are used with wonderful skill, such as no human 
 fingers could equal. 
 
 After a little while a number of entrances into the nest are 
 visible. They are almost invariably sheltered by projecting 
 leaves, which act as porches, so that when the nest is viewed 
 from above, they are almost entirely hidden. Each of these 
 openings runs into one of the main galleries of the nest, and 
 from thence issues a perfect labyrinth of passages.
 
 >'EST OF WOOD-ANT. 215 
 
 This, however, is only half the nest, for the galleries and 
 tunnels extend far beneath the surface of the earth, and have 
 sundry enlarged portions or chambers wherein the immature 
 pupae may lie during their period of helplessness. 
 
 Owing to the very loose structure of the upper nest, and the 
 tendency of the earth to fall into the galleries of the lower 
 nest, it is very difficult to obtain a trustworthy view of the 
 interior. Perhaps I may here be allowed to extract a passage 
 from my " Insects at Home," the description of the nest and 
 its interior having been written almost on the spot : 
 
 " I have, however, succeeded in obtaining an excellent view 
 into the interior of a Wood-ants' nest, though it was but a 
 short one. Accompanied by my friend Mr. JEL J. B. Han- 
 cock,* I was visiting some remarkably fine Wood- ants' nests 
 near Bagshot. We took with us a large piece of plate glass, 
 placed it edgewise on the top of an Ant-hill, and, standing one 
 at each side, cut the nest completely in two, leaving the glass 
 almost wholly buried in it. 
 
 "After the expiration of a few weeks, during which time 
 the ants could repair damages, we returned to the spot, and, 
 with a spade, removed one side of the nest as far as the glass, 
 which then served as a window through which we could look 
 into the nest. It was really a wonderful sight. 
 
 " The Ant-hill was honeycombed into passages and cells, in 
 all of which the inhabitants were hurriedly running about, 
 being alarmed at the unwonted admission of light into their 
 dwellings. In some of the chambers the pupae were treasured, 
 and these chambers were continually entered by Ants, which 
 picked up the helpless pupae, and carried them to other parts of 
 the nest where the unwelcome light had not shown itself. 
 
 " Unfortunately this view lasted only a short time. Owing 
 to the partial decomposition of the vegetable substances of 
 which the Ants' nest is made, the interior is always hot and 
 always moist. Now, the day on which we visited the nest 
 happened to be a cold one, and, in consequence, the moisture of 
 the nest was rapidly condensed on the inner surface of the 
 glass, and in a few minutes completely hid the nest from view, 
 leaving me only time to make a rapid sketch. Unfortunately 
 some one discovered the plate of glass and stole it. 
 
 " Next time that I examine a Wood-ants' nest, I shall take 
 
 * Now Sir Henry J. Burford Hancock, Chief Justice of Gibraltar.
 
 216 NATURE'S TEACHINGS. 
 
 care to insert the glass exactly east and west, and shall open 
 its southern side towards noon on a hot sunshiny day, so that 
 the rays of the sun may warm the glass and prevent evapora- 
 tion." 
 
 Many other creatures make subterranean dwellings, but the 
 Wood-ant is remarkable for possessing a double dwelling, the 
 two portions communicating with each other, and capable of 
 being used according to the degree of heat required. 
 
 THE PYRAMID. 
 
 WE have already seen how the Eddy stone lighthouse was 
 the precursor of many similar buildingsj all, like their pre- 
 decessor, having their form copied, with more or less strictness, 
 from the outlines of a tree-stem. 
 
 KATURAL MOUNTAIN. ARTIFICIAL MOUNTAIN, OB PYRAMID. 
 
 Another form of building which was intended for endurance, 
 and, indeed, is the most enduring of all shapes, is the Pyramid. 
 
 We are all familiar with the simple, yet grand outlines of 
 the Pyramids of Egypt, whose vast antiquity takes us back to 
 the times of Isaac and Joseph, and which seem capable of 
 resisting the effects of Time, the universal destroyer, for thou- 
 sands of years yet to come. 
 
 We may ask ourselves what was the natural object from 
 which the Pyramid was copied. The name itself, which is 
 formed from a Greek word signifying fire, shows that a flame 
 was thought to have furnished the idea of this form of building. 
 I cannot, however, but think that the flame had little, if any- 
 thing, to do with it, and that the real model may be found in 
 the hills which have been formed by Nature. 
 
 Examples of the Pyramids and the Hills are given in the 
 accompanying illustration.
 
 SUBAQUATIC ARCHITECTURE. 
 
 217 
 
 SUBAQUATIC MORTAR. PAINT AND VARNISH. 
 
 HAVING now disposed of the chief points in Architecture, 
 we take some of the subsidiary details. 
 
 Of late years, when the traffic between different continents 
 has so largely extended itself, and when shipping has increased 
 both in the numbers and dimensions of the vessels, it is 
 absolutely necessary that we should have harbours and docks 
 enlarged and multiplied sufficiently to meet the calls upon 
 them. 
 
 Now, it is comparatively easy to construct a building on 
 shore, for all the mortars and cements which are used for the 
 
 TEBEBELLA. 
 
 SUBMARINE MOBTAB. 
 
 purpose of fastening the stones together are applied when wet, 
 and incorporate themselves with the stones as they dry. But 
 to make a mortar which could be applied while the stones were 
 under water, and would "set" while beneath the surface, was 
 a task not easily to be overcome. Yet it has been done so 
 effectively that at the present day we can build beneath the 
 surface of the water as securely, though not as rapidly, as if the 
 stones tad been laid on dry ground. 
 
 Several such mortars are now known, and, as is so often the 
 case with human inventions, have been anticipated in Nature. 
 
 We have already seen how the Caddis-worm of the fresh
 
 218 NATURE'S TEACHINGS. 
 
 waters can cement together, while under water, the various 
 materials of which its tubular house is formed. The different 
 Sticklebacks perform similar feats, no matter whether they 
 inhabit fresh or salt water. 
 
 All those who take an interest in the productions of the sea- 
 shore will have noticed upon our coasts the flexible tube of the 
 Terebella, with its curiously fringed ends. This tube, as any 
 one may see at a glance, is composed of grains of sand and 
 similar materials, fastened strongly together by a kind of 
 cement exuded from the worm, and possessing the property of 
 hardening under water. As on some of our coasts fragments 
 of shell are used for the tube, the worm goes by the popular 
 name of Shell-binder. 
 
 If one of these worms be taken out of its tube, placed in 
 a vessel with sea-water and a quantity of sand, broken shells, 
 and little pebbles, the mode of building will soon be seen. At 
 the extremity of the head are a number of extremely mobile 
 tentacles, and these are stretched about in all directions, seizing 
 upon the particles of sand and shell, seeming to balance them 
 as if to decide whether they are suitable for the tube, and then 
 fixing them one by one with the cement which has already 
 been mentioned. 
 
 Generally speaking, the Terebella works only in the evening, 
 but, if it be hastily deprived of its tube, it cannot help itself, 
 and is perforce obliged to work while it can. It is worthy of 
 remark that the Terebella, although, as a rule, it lives in a tube 
 all its life, is capable of swimming with the usual serpentine 
 motion of marine worms, and, when taken out of its tube, 
 rushes about violently, and soon exhausts itself by its efforts. 
 
 Along most of our rocky seashores may be seen vast quan- 
 tities of a sort of hardened sand, penetrated with small tubes. 
 On a closer examination this sand-mass is resolved into a 
 congeries of tubes, matted and twisted together, and each being 
 the habitation of a marine worm called the Sabella. This name 
 is derived from a Latin word signifying sand, and is given to 
 the worm in allusion to the material of which it makes its 
 habitation. 
 
 Like the Terebella, the Sabella uses its tentacles for the 
 purpose of building the tubes, which are much stiffer than 
 those of the Terebella. They are strong enough, indeed, to
 
 PAINT. 219 
 
 give the feet a firm hold while traversing the rocks, and this, is 
 a matter of no small moment when the tide is coming in, and 
 the shore has to be regained without loss of time. 
 
 Then we have other marine worms, known as Triquetra 
 and Serpula, which make tubes in a somewhat similar 
 manner, but of very fine materials and very strong cement, so 
 that the tube is nearly as hard as stone. 
 
 Space would fail me if I were to enumerate these creatures 
 at greater length, but enough has been said to show that 
 man's invention of subaquatic cement has been anticipated in 
 Nature by the inhabitants both of salt and fresh water. 
 
 WE now come to the subject of Paint and Varnish. Putting 
 aside their use as a means to increase the beauty of the object 
 to which they are applied, we will view them in the light of 
 preservatives, and acknowledge the truth of the old Dutch pro- 
 verb, that " Paint costs nothing." Certainly, when the wood 
 to which it is applied is thoroughly dry from within, it not 
 only costs nothing, but repays itself over and over again as a 
 preservative of the wood, and a defence against moisture from 
 without. 
 
 The instances in which Paint is applied to wood are too 
 numerous to be mentioned. Perhaps some of my readers may 
 remember the case of the naval captain who, on taking com- 
 mand of his ship, was supplied, according to custom, with 
 exactly half the amount of paint required for her. The in- 
 variable etiquette had been that the captain supplied the 
 remaining half at his own cost. But the officer in question 
 was not at all disposed to be " put upon," and was a thorn in 
 the sides of the " Naval Lords." 
 
 Finding, by actual measurement, that the paint supplied to 
 him was only half the amount which was really needed for the 
 ship, he sent his respectful compliments to the Admiralty, 
 asking whether they wished the port or the starboard side of 
 the ship to be painted, for that there was only enough paint 
 for one half of the ship, and he awaited instructions as to which 
 side of the vessel it was to be applied. He was impervious to 
 "minutes," "directions," &c., and, as 'far as I remember, this 
 very impracticable man got his way, and was supplied with the 
 requisite amount of paint.
 
 220 
 
 NATURE S TEACHINGS. 
 
 LONG before man ever invented paint or varnish the Hive 
 Bee had made use of it. 
 
 Every one who has kept bees knows how they always fasten 
 the edge of the hive to the board, and stop up any crevices 
 that may be left open. The material which they use for this 
 purpose is not wax, but a substance called " propolis." This 
 
 BEE VARN'ISHING CELLS. 
 
 PAINTER VABNISMIXG WOOD. 
 
 term is composed of two Greek words, signifying a suburb, or 
 the outskirts of a town, and is given to this stationary sub- 
 stance in consequence of the use which is made of it. 
 
 Not only do the bees use it for fastening the hives, but 
 also for strengthening their combs. Wax is a very precious 
 material, and the beautiful hexagonal structure of the bee-comb 
 is intended for the purpose of combining the greatest amount of 
 storing space with the least expenditure of material. The 
 plates of wax of which the cells are composed are so thin that 
 their edges would break down even under the feet of the bees 
 as they passed over it, and accordingly the bees strengthen 
 the edges of the cells with propolis, as any one may see by 
 examining a piece of bee-comb. The propolis is of a darker 
 colour than the wax, and has a peculiar varnish-like appear- 
 ance. 
 
 The propolis, as distinguished from wax, is mentioned by 
 Virgil in his Georgics : 
 
 " Collectumque haec ipsa ad munera gluten 
 Et visco et Phrygise servant pice lentius Idse." Georg. iv. 40. 
 
 It is evident that the propolis cannot be obtained from the 
 same source as the wax. The latter is secreted by the bees
 
 VARNISH. 221 
 
 under little plates or flaps upon the abdomen, while the 
 propolis is purely a vegetable exudation. It is obtained from 
 many trees, the principal being the horse chestnut. All who 
 have handled the buds of this tree are aware that they are 
 covered with a viscous and very adhesive matter, which serves 
 as a varnish or protection to the bud before the leaves are 
 strong enough to break out. This is the material which the 
 bees gather for their propolis, and at certain times of the year 
 the chestnuts may be seen swarming with bees, all busily 
 engaged in scraping off the varnish.
 
 TOOLS. 
 
 CHAPTER I. 
 
 THE DIGGING-STICK. SPADE. SHEARS AND SCISSORS. CHISEL 
 AND ADZE. THE PLANE AND SPOKESHAVE. 
 
 The Use of Tools a Distinction between Man and Beast. All Men, however 
 savage, use Tools, but none of the lower Animals can do so until taught by 
 Man. Tools needed to break up the Ground. The Digging-stick of savage 
 Life : its Use and its Efficacy in practised Hands. Digging-sticks in Nature. 
 The Heart-urchin, and its Mode of digging in the Sand. The Spade : 
 its Shapes and Uses. Natural Spades. Fore-foot of the Mole and Mole- 
 cricket. The Aard-vark, the Ant-eater, and the Mattock. Shears and 
 Scissors a Sign of Civilisation, never being employed by Savages. Mecha- 
 nical Principle of Scissors, the Inclined Plane, the Lever, and the Cutting 
 Edge. Chinese Shears and the Pruning Scissors. Use of the Inclined 
 Plane. The Diagonal Knife of the Guillotine. The Shears in Iron-works. 
 ihe "Drawing Cut" of Swordsmen. Jaws of the Turtle and Tortoise. 
 The Snapping Turtle nnd the Chicken Tortoise. The Locust, the Cock- 
 chafer Grub, the Gi eat Green Grasshopper, and the Wart-biter. The Leaf- 
 cutter Bees and their fsests. The Chisel and Adze. Structure of Rodent 
 Tooth and Chisel. Uo of ihe hard Plate of Enamel or Steel. Combination 
 of hard and soft Materials. Teeth of Hippopotamus and Hyrax. Principle 
 of the Adze. Self-sharpening and Self-renewing Tools. The Plane and 
 Spokeshave. Principle on which they are made. The Spokeshave and 
 its Uses. The " Guard " Razor. The Hoop-shaver Bee and its Nest. Its 
 natural Plane, and the Use which is made of it. 
 
 A MONGr the many points of distinction between man and the 
 " lower animals, we may consider the use of tools as one of 
 the principal lines of demarcation. Man stands absolutely 
 alone in this respect. There is no race of savages, however 
 degraded they may be, that does not employ tools of some kind, 
 and there is no beast, however intelligent, that ever used a tool 
 except when instructed by man. 
 
 As to the stories that are told of the larger apes using 
 sticks and stones by way of weapons, they are absolutely with- 
 out foundation, no animal employing any tool or weapon save 
 those given to them by Nature. It is true that a monkey may
 
 DIGGING TOOLS. 223 
 
 sometimes be seen to take a stone for the purpose of cracking 
 nuts which are too strong for its teeth, and to perform that 
 task with great deftness ; but such animals have always been 
 taught by man, and had they remained in their own country, 
 not one of them would have used a stone, were the nuts ever 
 so hard. 
 
 THE SPADE. 
 
 WE will begin our notice of tools by taking that which must 
 have been the first tool invented by man. One of the principal 
 duties assigned to man is the culture of the earth, and this he 
 cannot do without tools, increasing their number and improving 
 their structure in proportion to his own development in agri- 
 culture. 
 
 Before seed can be sown, it is necessary that the earth should 
 be broken up, and, owing to the structure of the human frame, 
 
 HEART-URCHIN. DIGGING -STICK. 
 
 this task cannot be fulfilled by man without a tool which will 
 enable him to rival many of the lower animals, i.e. make use 
 of those digging appliances which have been furnished by 
 Nature. 
 
 It is evident that the first earth-breaking tool must have 
 been a pointed stick, and we find that in Southern Africa, in 
 parts of Asia, and in Australia the Digging-stick is still in 
 use for the purpose of breaking up the ground. The Austra- 
 lians are wonderful adepts in the use of the Digging-stick, 
 which is one of the simplest of instruments, being merely a 
 stick some two feet in length, pointed at one end, and the point 
 hardened in the fire. 
 
 The mode of using it is by holding it perpendicularly, 
 pecking it into the ground, and throwing out the loosened soil 
 with the hands. In this way they can excavate with such
 
 224 NATURE'S TEACHINGS. 
 
 rapidity, that a strong navvy, armed with the best spade, would 
 not be able to keep pace with a black man armed only with his 
 " katta," or digging-stick. 
 
 In Africa the Digging-stick is used in exactly the same 
 manner, and is generally made more weighty and effective by 
 having a perforatod stone fastened on the handle. 
 
 HERE, again, man has been anticipated by Nature, and the 
 savage of Australia or Africa digs in exactly the same manner 
 as the common Heart-urchin of our shores, sometimes called the 
 Hairy Urchin, in consequence of the number and fineness oi 
 the spines, which look just like hairs to the naked eye. The 
 scientific name of this creature is AmpMdotus cordatm. 
 
 Mr. Gosse, in his "Evenings at the Microscope," gives so 
 admirable an account of the mode of digging employed by the 
 Hairy Urchin that I cannot do better than employ his own 
 words. After describing the variety of structure of the different 
 spines with which the shell is so thickly set, he proceeds as 
 follows : 
 
 " But what is the need of so much care being bestowed upon 
 the separate motion of these thousands of hair-like spines, that 
 each should have a special structure, with special muscles for 
 its individual movement ? The hairs of our head we cannot 
 move individually : why should the Heart-urchin move his ? 
 
 " Truly, these hairs are the feet with which he moves. The 
 animal inhabits the sand at the bottom of the sea in our shallow 
 bays, and burrows in it. By going carefully, with the lens at 
 your eye, over the shell, you perceive that the spines, though all 
 formed on a common model, differ considerably in the detail of 
 their form. I have shown you what may be considered the 
 average shape, but in some, especially the finer ones that clothe 
 the sides, the club is slender and pointed ; in others, as in those 
 behind the mouth, which are the largest and coarsest of all, the 
 club is dilated into a long, flat spoon ; while in the long, much- 
 bowed spines, which densely crowd upon the back, the form is 
 almost uniformly taper throughout, and pointed. 
 
 " The animal sinks into the sand mouth downwards. The 
 hard spoons behind the mouth come first into requisition, 
 scooping away the sand, each acting individually, and throwing 
 it outwards. Observe how beautifully they are arranged for
 
 THE SPADE. 225 
 
 this purpose, diverging from the median line, with the curve 
 backwards and outwards. 
 
 "Similar is the arrangement of the slender side spines; 
 their curve is still more backwards, the tips arching uniformly 
 outwards. They take, indeed, exactly the curve which the 
 fore-paws of a mole possess, only in a retrograde direction, 
 since the Urchin sinks backwards, which has been shown 
 to be so effective for the excavation of the soil, and the throw- 
 ing of it outwards. 
 
 " Finally, the long spines on the back are suited to reach the 
 sand on each side, when the creature has descended to its 
 depth, and by their motion work it in again, covering and con- 
 cealing the industrious and effective miner." 
 
 The reader will notice that this mode of digging is exactly 
 like that which is followed by the users of the Digging-stick, 
 the earth being first broken up, and the loosened portions 
 thrown aside. The whole of the description of the spines is 
 exceedingly interesting, but, as it does not bear directly on the 
 present subject, I cannot admit it into these pages. 
 
 Now comes another development in digging tools. 
 
 We have already seen how effective an instrument a mere 
 piece of stick can be in the hands of a skilful workman, and 
 the manner in which it can tear up a given depth of soil. 
 But, for agricultural purposes, something more is needed, and 
 the ground must not only be broken up, but a certain regu- 
 larity must be observed, in order to allow space to be accu- 
 rately measured, and the crop apportioned to the area. 
 
 Out of the Digging-stick, then, the Spade was developed, its 
 chief advantage being that it dispensed with the use of the 
 bare hands, and not only tore up the ground, but threw out 
 the loosened soil. 
 
 The reader will remember that in the preceding description 
 of the Heart-urchin it was mentioned that many of the 
 spines are shaped at their ends something like spoons, and 
 that their comparatively wide blades are used in scraping the 
 sand and shovelling it aside. In fact, these flattened spines 
 are natural spades, used on the same principle as the modern 
 spade of civilisation. 
 
 On the right hand of the illustration are shown two forms of 
 
 Q
 
 226 
 
 NATURE'S TEACHINGS. 
 
 spade, the one being the ordinary garden tool, and the other a 
 rather curious implement which is in great use among the 
 metal mines of Cornwall. The use of the ordinary spade is too 
 familiar to need explanation, and we come to the Miner's spade. 
 This implement is used rather as a shovel than as a spade, the 
 peculiar hend near the blade preventing the foot from being 
 used as a means of forcing the instrument into the ground. 
 In fact, it is not meant for the same office as that which pertains 
 to the ordinary spade, neither can it be handled in the same 
 way. 
 
 In Devonshire there is a kind of spade in general use very 
 much resembling the mining spade, but having a very long 
 
 FOOT OP AAED-VAEK. FOOT OP MOLE-CBICKET. 
 FOOT OF MOLE. 
 
 handle without any crutch at the end. The natural conse- 
 quence of this shape is, that the spade cannot be used in the 
 ordinary way, neither can it penetrate the earth to any 
 depth. It can " peel " the ground, so to speak, and can cut 
 away successive layers of soil. But as for digging "two 
 spits deep," or even one spit, the spade would be absolutely 
 incapable of such a task, no matter how strong might be the 
 hands that wield it. As for the foot, it may be put out of the 
 question. 
 
 WE will now turn to a few examples of spades in the world 
 of Nature. 
 
 The lowest figure represents the fore-paw of the Mole,
 
 MOLE, MOLE-CRICKET, AND ANT-BEAR. 227 
 
 with its powerful armature of strong and sharp claws, and its 
 broad blade of a palm. The reader will easily see that in 
 this animal the digging powers are wonderfully developed. 
 The peculiar form of the fore- foot closely resembles that of 
 the miner's spade, while the curvature of the palm serves, 
 almost without exertion, to throw out the earth which has 
 been scooped away by the sharp claws. 
 
 To watch a Mole burrow is really a curious sight, the only 
 drawback being that the animal sinks itself so rapidly beneath 
 the earth that a long inspection is impossible. I have kept 
 several moles for the purpose of watching their habits, and 
 have always been interested in their mode of burrowing. I 
 can only define it by using the word " scrabbling." The 
 animal scurries and hurries about, seeking for a tolerably soft 
 piece of ground. When it has found one, it travels no further, 
 but scratches away with its fore-paws with wonderful power 
 and rapidity, seeming to sink, as it were, into the earth, rather 
 than to excavate a tunnel. 
 
 THERE is an insect well known to entomologists, called the 
 Mole-cricket, because its structure and many of its habits are 
 strangely similar to those of the animal from which it derives 
 its name. At the upper part of the illustration is seen a portion 
 of the fore-foot of the Mole-cricket, and a better implement of 
 excavation can hardly be imagined. 
 
 The reader will probably have noticed that in both these 
 creatures the spade, if we may so call it, is not a mere flat 
 plate, but is cleft into several points. It thus answers the 
 purpose of a fork as well as a spade, the several points serving 
 to break up the soil, and the flat palm to throw the earth 
 aside. 
 
 This principle is carried out even more fully in the fore- 
 paw of the African Ant-bear, or Aard-vark (Orycteropus 
 Capensis), a figure of which is given in the illustration. This 
 animal is a great excavator, living in burrows of such dimen- 
 sions that the wild boar is in the habit of making its home 
 in them after they are deserted. 
 
 Something more, however, than a digging apparatus is 
 needed for the Ant-bear. This animal feeds almost wholly on 
 the Termites, which it obtains by tearing down the walls of 
 
 Q 2
 
 228 NATURE'S TEACHINGS. 
 
 their dwellings. Now, as these wonderful buildings are nearly 
 as hard as brick, and, indeed, are composed of the same materials, 
 it is necessary that the claws of the Ant-bear should be modified 
 so as to be able to break through the walls. Accordingly, 
 they are much more curved than those of the Mole and the 
 Mole-cricket, and so serve for tearing as well as digging, being 
 struck into the wall, and thus pulling it down, just as a 
 labourer breaks down a bank with his mattock. 
 
 Indeed, had we wished to extend these analogies still further, 
 we might easily have given the claws of the Aard-vark as a 
 prototype of our English mattock. The same weapons as 
 possessed by the Ant-bear of tropical America are used in 
 exactly the same manner, but are even stronger, and extend to 
 such a length that when the animal walks, it cannot stretch its 
 claws out in front, but is obliged to double them under its feet. 
 
 SHEARS AND SCISSORS. 
 
 THESE instruments are sure signs of civilisation, no savage 
 nations having the least idea of them. Even the Kafir and Esqui- 
 maux tribes, which are such admirable workers in skin, never 
 use scissors in shaping their garments, but invariably employ 
 knives for that purpose. The Chinese, however, seem to have 
 known scissors from time immemorial, and to have shaped them 
 almost exactly like our own instruments. I possess one pair 
 of tailor's shears from China in which there is only one ring, 
 namely, that for the thumb. The place of the other ring is 
 taken by an elongated, slightly curved and moderately pointed 
 rod of steel, which is used for tracing the pattern on the material 
 preparatory to cutting it. 
 
 Simple as the scissors may seem, they combine several very 
 important principles, namely, the inclined plane, the lever, and 
 ihe cutting edge. Were they to be merely two edges moving 
 directly upon each other, their effect would be comparatively 
 slight ; but, owing to the manner in which the blades are fixed 
 at one end, they are drawn as it were over the object between 
 them, and so divide it with comparative ease. In some instru- 
 ments, such as the pruning scissors, there is only one cutting 
 blade, the other being used merely as a support for the branch 
 which is being cut.
 
 SHEARS AND SCISSORS. 229 
 
 A well-known example of a single cutting blade is found in 
 the guillotine. In the earliest times of this invention an 
 ordinary axe-head was suspended above the neck of the criminal. 
 It was found, however, that its operation was very uncertain, 
 simply because the blow was a direct one, and not oblique. The 
 blade was then set obliquely, as in the present machine, and 
 its effect was absolutely certain. 
 
 Perhaps some of my readers may be swordsmen, and there- 
 fore know the power of the "drawing cut," by which a great effect 
 may be produced with very little apparent exertion. Even in 
 the simple operation of cutting bread we always use the knife 
 diagonally, though perhaps we may be ignorant of the principle 
 of the inclined plane. 
 
 Next comes the principle of the lever, as exemplified by the 
 handles of the scissors. By lengthening these handles, the 
 power of the blades is enormously increased, as may be seen in 
 the various shears in any great iron-works, which cut through 
 thick iron as if it were butter. Our own garden shears for 
 trimming borders show very well the power of the long arms 
 and short blade. 
 
 IN the animal world we find many examples of natural shears, 
 one of the best of which is afforded by the jaws of the Tortoise 
 or Turtle. Owing to the manner in which they feed, whether 
 they be vegetarians or carnivorous, their jaws are made for 
 cutting, and not for lacerating or mastication. They have n* 
 teeth, but each jaw is furnished with a horny edge, as sharp a& 
 a knife-blade, and very strongly made. With these jaws the 
 animal can shred to pieces the objects which it attacks, just as 
 if it had been furnished with a pair of veritable shears. Any 
 one who has possessed an ordinary Tortoise must have noticed 
 the havoc which it will occasionally make in a garden. I had 
 one of these reptiles for some years, and was obliged to keep it 
 under restraint, in consequence of the power of its jaws. 
 
 Being a Tortoise of discrimination, it took a great fancy to 
 the strawberry beds, and invariably picked out the ripest and 
 best-flavoured fruit. Reversing the usual proverb of making 
 two bites at a cherry, the Tortoise always took two bites at a 
 strawberry, and sometimes three or four, according to its size. 
 
 At last, I was obliged to restrain it by boring a hole in the
 
 230 NATURE'S TEACHINGS. 
 
 edge of its shell, passing one end of a string through it, and 
 fastening the other to a peg driven into the ground. At first, 
 I tied the string to a brick, but the Tortoise was so strong that 
 it dragged the brick about the garden, leaving reminiscences of 
 its progress in the channels which it had cut through all kinds 
 of vegetation with its scissor-like jaws. 
 
 The reader, in comparing the illustration of the Turtle-jaws 
 with that of the Shears, will see at once how exact is the 
 analogy between the two. The sharp-edged jaws correspond 
 with the blades of the shears, the joint at the skull corresponds 
 with the pivot of the shears, and the muscles which move the 
 
 JAWS OF TURTLE. 
 
 jaws, but which could not be shown in the present illustration, 
 are the prototypes of the handles. 
 
 In some of these creatures, especially those which are car- 
 nivorous, the power of the jaw is tremendous. One of them, 
 a Snapping Turtle, has been known to bite off several fingers 
 of a man's hand as easily as if they had been carrots. Some 
 years ago I kept some Chicken Tortoises alive, and was much 
 struck with the enormous proportionate power of their jaws. 
 
 They were quite little creatures, only a few inches in length, 
 but their appetites were astonishing, and their mode of 
 satisfying their hunger remarkable. They were always 
 ravenous after meat, and had a curious way of seizing their 
 food in their mouths, placing one paw on either side of their 
 jaws, and then pushing the meat forcibly away, so as to cut 
 out a slice as large as their jaws. 
 
 They were very good-tempered little things, but, small 
 though they were, I should have been very sorry to have one 
 of them take a bite at my finger by mistake.
 
 LEAF-CUTTER BEES. 231 
 
 Knowing their general characteristics, I took care not to 
 have any living creature in the same vessel. But I have heard, 
 from those who have had practical experience, that Chicken 
 Tortoises ought to be banished from any place wherein fish 
 are kept, especially if they be gold fish, the Tortoise having a 
 way of coming quietly beneath them, biting out a mouthful of 
 their bodies, and then disappearing with its booty. 
 
 BESIDE the Tortoise, there are many creatures which possess 
 natural shears, such as the Locust, whose ravages are only too 
 notorious. Then, taking our own country, we have plenty of 
 examples of insect shears. Such is to be found in the jaws of 
 the Cockchafer larva, or "White Grub " as it is popularly called. 
 It lives underground, and feeds chiefly on the roots of herbage, 
 shredding them to pieces with its shear-like jaws. And, as it 
 spends on the average three years in the one task of perpetual 
 eating, the damage which it does can be easily imagined. 
 
 There is a very pretty English insect which admirably 
 exemplifies the power of the natural scissors. This is the 
 Great Green Grasshopper (Acrida viridissimd), which is equally 
 voracious in all its stages of existence. It is always ready to 
 use these jaws, and I do not recommend the reader to allow his 
 finger to get between them, or their points will probably 
 meet. 
 
 One of these insects, indeed (Decticus griseus), has derived 
 the name of Wart-biter from its supposed use in curing warts. 
 All that was needful was to catch a Wart-biter, and hold one 
 of the warts to its jaws. It was sure to seize the wart, 
 and bite it smartly, and there was a firm belief that any one 
 thus bitten would be freed from the unsightly excrescence. 
 The bite of the shear-like jaws caused much pain at the time, 
 and this very pain had in all probability something to do with 
 the cure. 
 
 AN admirable example of the insect jaws used as scissors is 
 to be found in the well-known Leaf-cutter Bees, insects belong- 
 ing to the genus Megachile. 
 
 They make their nests in burrows, sometimes in wood, and 
 sometimes in the ground, and form them in a very singular 
 manner. After fixing upon a suitable burrow, the Bee goes off
 
 232 NATURE'S TEACHINGS. 
 
 to a tree, generally a rose, and, using her jaws just as a tailor 
 uses his shears, cuts off a nearly semicircular piece of leaf, flies 
 away with it to her home, and, by dint of bending, pushing, 
 and pulling it, she forces it to the bottom of the cell. Suc- 
 cessive pieces of leaf follow, until she has made a thimble- 
 shaped cell, and she then places at its end an egg and a supply 
 of honey and pollen. 
 
 Cell after cell succeeds, each being introduced into its prede- 
 cessor just as thimbles are packed. Judging from a specimen 
 in my collection, there are about eight layers of leaves to form 
 the walls of the cell, and the average length of each piece of 
 leaf rather exceeds half an inch. The entire length of the 
 cell-group is two inches and a half. The leaf-slices are always 
 cut from the edge, and, in my specimen of the nest, the serrated 
 outer edges of the leaves are all in one direction. 
 
 Should any of my readers find one of these nests, it will be 
 as well for them to dip a needle point into diamond cement, 
 and introduce it under the outermost coating of leaves. Other- 
 wise, when the leaves are dry, and the insects break their way 
 into the open air, the cells will probably fall to pieces. 
 
 These Bees are much more abundant than is usually thought. 
 In summer-time it is hardly possible to find a rose-bush on 
 which are not a number of leaves from which pieces of variable 
 size and shape, but always with a curved outline, have been 
 cut as with scissors. While cutting them, the Bee seems to 
 trace out her pattern, as it were, by using her feet like one leg 
 of a pair of compasses, and her head as the other leg. As 
 soon as she has nearly finished the operation, she poises herself 
 on the wing, to prevent her weight from tearing away the leaf 
 irregularly, and then, while still on the wing, makes the last 
 few bites, and severs the leaf entirely. 
 
 THE CHISEL AND THE ADZE. 
 
 ALREADY we have seen how exact is the analogy between 
 the scissors and the turtle-jaw. As we are upon the subject of 
 cutting instruments, we will continue it, trying to discover 
 some further analogies. 
 
 On the right hand of the illustrations we see three cutting 
 tools made by human hands i.e. the Chisel, the Stone Adze of
 
 THE CHISEL. 233 
 
 Polynesia, and the Steel Adze of this country. We begin with 
 the Chisel. 
 
 All those who have even a slight knowledge of anatomy 
 know how curiously exact is the resemblance of the Chisel of 
 civilised life to the front tooth of any Rodent animal. The 
 head of the Beaver is here given as an example, but the tooth 
 of a mouse, rat, or rabbit, which can easily be obtained, is 
 quite as good an example. These teeth are made after a very 
 beautiful fashion. Their outer surface is covered with a plate 
 of very hard enamel, while the rest of the tooth is of bony 
 matter, and comparatively soft. Consequently, when the tooth 
 is used, the enamel plate forms a sharp edge, while the rest of 
 it is worn away, thus keeping the chisel-like end in its proper 
 form. 
 
 The power of these teeth may be appreciated by any one 
 who has been bitten even by so small a rodent as a mouse, the 
 
 TOOTH AND JAWS OF BEATEB. 
 
 sharp edges meeting in the flesh, and causing a very painful 
 wound. When the teeth are large, as in the Beaver, and the 
 jaws powerful, their force is something wonderful, tree-trunks 
 of considerable size being cut down quite easily. 
 
 Perhaps some of my readers may not be aware that the 
 Chisel is constructed on exactly the same principle as the tooth 
 of the Rodent animal. It is not entirely made of steel, as is 
 generally thought. In the first place, a valuable material 
 would be needlessly wasted, and, in the next place, the tool 
 would not keep its edge except with infinite labour in grinding. 
 
 The principal part of the Chisel-blade is therefore made of 
 soft iron, a very thin plate of steel running along the back. 
 This plate answers the same purpose as the enamel in the tooth, 
 while the soft iron takes the place of the soft bone. Axe- 
 blades, which are, in fact, formed like two chisels placed back 
 to back, are made on a similar principle, except that the steel
 
 234 NATURE'S TEACHINGS. 
 
 plate occupies the centre of the blade, and the soft iron is on 
 either side. Thus the thin plate of steel is easily brought to an 
 edge, while the soft iron can be ground away without any diffi- 
 culty. 
 
 I do not mean to state that the inventor of this combination 
 of thin steel and soft iron had taken his idea from the Rodent 
 tooth, but only to show that the invention, beautiful, simple, 
 and ingenious as it is, has its prototype in Nature. I may 
 here mention that the Plane-iron, which is, in fact, a modified 
 Chisel, is made in exactly the same fashion. 
 
 NEXT we come to the Adze. 
 
 In some respects there is much resemblance between the 
 blade of the Adze and the teeth of the Rodent, especially in 
 their curve, which is almost identical in both. This form is 
 
 ADZE-TEETH OF HIPPOPOTAMUS. STONE ADZE OF POLYNESIA. 
 
 STEEL ADZE. 
 
 seen in the structure of other teeth than those of Rodents. 
 There is, for example, the tooth of the Hippopotamus, which is 
 not only curved, like that of the Rodent, but bevelled off in a 
 similar way at the tip. With these formidable teeth, one of 
 which is now before me, the Hippopotamus makes terrible 
 havoc among the herbage, mowing it down, so to speak, and 
 stowing it away wholesale in its enormous stomach. A Hippo- 
 potamus indeed, when angered, has been known to sever a 
 man's body completely in two with a single bite, so trenchant 
 are the teeth, and so powerful the jaws. 
 
 Then there is a little animal called the Hyrax, or Rock- 
 rabbit, which is the coney of Scripture. This creature is really 
 one of the pachydermatous group, although its small size, hairy 
 coat, its activity among the rocks, and its apparently rodent
 
 THE PLANE. 235 
 
 teeth, have induced many persons to place it among that group. 
 These teeth, however, like those of the Hippopotamus, are 
 bevelled off at their tips, and, as they perform a similar office, 
 they take a similar curve. 
 
 It is worthy of notice that in the Stone Adze the hevelled 
 edge much more resembles the rodent tooth than does the 
 Steel Adze, the reason being evidently that stone is more 
 fragile than steel, and requires greater thickness. Still, the 
 principle is the same in both, only the metal is more attenuated 
 than the stone. 
 
 The Rodent or Hippopotamus tooth has still a great 
 advantage over any chisel or adze made by man, whether of 
 stone or metal. As our tools are blunted, we are forced to 
 spend much time in sharpening them, and by degrees grind 
 the tool away until it becomes useless. Now, the teeth are so 
 arranged that their perpetual use, instead of blunting, only 
 sharpens them, and in proportion as they are worn away in 
 front they are supplied with fresh matter from behind, and per- 
 petually pushed forwards, so that they are self-renewing as 
 well as self-sharpening. 
 
 THE PLANE AND SPOKESHAVE. 
 
 I HAVE already made mention of the Plane in connection 
 with the Chisel, and shown that, like that tool, it is formed on 
 the same principle as the Rodent tooth. 
 
 The use of this important instrument in carpentering can- 
 not be overrated, as is shown by the numberless varieties 
 which are used by carpenters, and the different uses to which 
 they are put, sometimes merely smoothing a level surface, 
 and sometimes forming a " moulding " where ornament is 
 required. 
 
 In principle, a Plane is a cutting edge or chisel, pushed along 
 the object to be worked, and, the edge being guarded, taking 
 off a very thin shaving from the surface. 
 
 On the right hand of the accompanying illustration is 
 shown the Plane in action, with the thin shavings falling from 
 it in curled masses. Perhaps some of my readers may have 
 visited some of the great iron-works, and been struck with the 
 use of the Plane as applied to metal instead of wood, long iron
 
 236 
 
 NATURE S TEACHINGS. 
 
 shavings being taken off as easily as if they were deal, and 
 curling in just the same manner. 
 
 THERE is an instrument very familiar to carpenters, called 
 the Spokeshave, on account of its use in trimming the spokes 
 of wheels. Different as it may be in appearance, it is identical 
 in principle with the plane, having an edge guarded by a piece 
 of wood, so that the blade cannot cut too deeply into the object 
 on which it is employed. The chief distinction, indeed, is, that 
 the workman, instead of pushing the blade from him, draws it 
 to him. 
 
 "When shaving was more in fashion than it is in these more 
 
 HOOP- SHAVER BEE. 
 
 PLANE. 
 
 SPOKESHAVE. 
 
 sensible days, there were many inventions to lessen the trouble, 
 not to say the perils, of shaving. To use the razor in a hurry 
 was anything but an agreeable occupation, especially if the 
 weather were frosty, and the fingers so chilled that they hardly 
 knew whether or not they had the razor between them. 
 
 In order to render this very unpleasant task less disagreeable, 
 some ingenious individual invented the Guard Razor. The 
 principal part of the invention consisted in a plate of metal 
 sufficiently thin not to add materially to the weight of the 
 razor, and sufficiently strong to resist a moderate amount of 
 pressure. This was fixed along the blade of the razor in such 
 a way that it just allowed the edge to show itself, and, in fact,
 
 THE HOOP-SHAVER BEE. 237 
 
 converted the razor into a plane or spokeshave. The exact 
 amount of edge which might be shown was regulated by screws, 
 and the guard itself could be removed at pleasure, so as to 
 allow of the razor being sharpened. 
 
 Now let us see if we can find any examples of the Plane or 
 Spokeshave in Nature. 
 
 I TRACE at least one example of the Plane in the insect 
 world. More than a hundred years ago, that very observant 
 naturalist, Gilbert White, noticed a bee performing a curious 
 task. She was running up the stem of the garden campion, 
 holding her jaws extended, and stripping off the down with 
 all the dexterity of a hoop- shaver. She collected a bundle 
 nearly .as large as herself, and then flew away with it. What 
 she did with her burden he knew not, but the history of the 
 insect has been told fully, though briefly, by Mr. F. Smith, in 
 his " Catalogue of British Hymenoptera :" 
 
 " Although the species belonging to this genus are numerous, 
 and are found both in the Old and New World, there is only 
 one found in this country, Anthidium manicatum ; this is truly 
 a summer bee, not making its appearance before the latter part 
 of June or beginning of July. 
 
 " This insect, so far as my own observation has enabled me to 
 ascertain, does not construct its own burrow, but makes use of 
 any hole which is adapted to its purpose. I once detected a 
 bee entering the hole above the wheel of the sash-line in a 
 summer-house ; but its nests are most commonly formed in the 
 holes bored in old willow stumps by Cossus ligniperda (the Goat- 
 moth) : formerly they were easily obtained in Battersea Fields, 
 where the willows abounded. 
 
 " It is probable that when the parent insect has selected one 
 of these ready-formed tunnels, she enlarges the end used as the 
 depository of the nest, and this is easily effected, as the stumps 
 in question, at the depth of a couple of inches, consist of soft 
 decayed wood. 
 
 " The chamber being formed, the bee collects a quantity of 
 down from woolly-stemmed plants, with which she forms an 
 outer coating. She then constructs a number of cells for the 
 reception of the pollen, or food of the larva ; they consist of a 
 woolly material, mixed with some glutinous matter which
 
 238 NATURE'S TEACHINGS. 
 
 resists the moisture of the food they contain, and in which the 
 larva, being full fed, spins a brown silken cocoon. These bees 
 pass the winter in a larva state, and do not appear until mid- 
 summer. 
 
 " In one respect, the sexes of this genus differ from most 
 other bees, the males being much larger than the females." 
 
 The reader will see from this account how exact is the 
 analogy between the carpenter's plane and the jaws of the bee. 
 In consequence of the simile employed by Mr. White, the 
 insect has been popularly known by the title of the Hoop-shaver 
 Bee. It is a tolerably common insect, and abounds in the 
 South of England.
 
 TOOLS. 
 
 CHAPTER II. 
 
 THE SAW AND ITS VARIETIES. 
 
 Cutting Tools and their working. Structure of the Edge. The Kris. Edge of 
 a Razor. The Sword and the Apple. Australian Saw. Fretwork Saw. 
 Various Saw-flies. The Pioneer's Saw. Cutting Tools of Trichiosoma. 
 Side Teeth of the Saws. The Cordon Saw, or Band Saw. Tooth-ribhon of 
 Whelks, Slugs, and other Molluscs. The Dog-whelk, or Purpura. The 
 Circular Saw. Sawyer-beetles and their Mode of Work. 
 
 STILL keeping to the Cutting Tools and their varieties, we 
 come to the Saw, i.e. the cutting tool set with teeth upon 
 its edge. Now, in plain fact, there is no cutting instrument 
 that does not more or less partake of the character of the Saw ; 
 for, in the first place, it is absolutely impossible for man to 
 grind an edge so fine that, when magnified, it will not appear 
 to be deeply notched, and, in the next place, its cutting powers 
 are greatly due to the notches and teeth, and the direction of 
 their points. 
 
 We will take both these subjects in turn. 
 
 First, as to the notches, or serrated edge. I have now before 
 me two instruments, each the best of their kind, and in both 
 of which the serrations are essential to efficacy. The first is a 
 Malayan dagger, or " kris," and the second is a surgeon's 
 lancet, made by Ferguson, of London. 
 
 In the kris the edge is intentionally serrated, having been 
 eaten away by means of acids until the required effect was 
 produced. The Malayans know by experience that such an 
 edge is most deadly in a weapon, and that it will cut certain 
 vital parts which a smoother edge might pass without doing 
 any damage. 
 
 Now we will take the lancet, and put it under the micro-
 
 240 NATURE'S TEACHINGS. 
 
 scope, when it assumes the most curious resemblance to the 
 kris. Its mirror-like surface looks as if it had been very roughly 
 treated with a coarse file, while its thin and delicate edge, 
 which is perfectly smooth to the eye, and which will pass 
 through a piece of stretched wash-leather without any apparent 
 opposition, becomes as rough and jagged as that of the Malayan 
 weapon. 
 
 Take even, for example, the common butcher's knife, which 
 is perpetually being sharpened on the " steel " that hangs at 
 his belt. The reader may observe that the butcher does not 
 rub the blade of his knife backwards and forwards on the steel, 
 as unskilful persons do. Rapid as is the movement gained by 
 constant practice, any one may see that the blade is always 
 moved in one direction, so as to force the microscopical teeth to 
 point one way, and so to act as a saw when the knife is drawn 
 across the meat. 
 
 The power of these teeth or notches may be inferred from 
 a well-known fact. If a razor, no matter how sharp, be pressed 
 upon the human skin without any " draw," it will indent the 
 skin, but not cut it, while the slightest drawing movement will 
 cause a deep wound. It is the knowledge of this fact that 
 enables an expert swordsman to sever an apple placed on the 
 palm of the bare hand, without even scratching the skin. I 
 have witnessed this feat, and at once saw that it was due to the 
 absence of any " draw " to the cut. The apple was laid on the 
 palm of the hand, which was opened as widely as possible, so 
 as to flatten it. The sword was then brought down on the apple 
 with a sort of chopping movement, so that, although it indented 
 the skin, it did not even inflict a scratch. 
 
 By the use of the " drawing " movement, the same sword 
 severed a gauze veil laid across it, the two halves floating in 
 opposite directions. By the same cut, I have seen some asto- 
 nishing feats performed with an Indian sword now in my collec- 
 tion, the objects of attack falling asunder as if by magic, without 
 any apparent force being used. 
 
 HAVING now glanced at the principle of the Saw, we will 
 proceed to some of its details. 
 
 The simplest form of Saw in existence is that which is in use 
 among the Australian natives, and consists of obsidian flakes
 
 NATURAL SAWS. 
 
 241 
 
 set along one side of a stick. It looks a rude and inefficient 
 affair enough, but it can cut better than might have been 
 thought, as I can testify from experiments on such a saw in 
 my collection. 
 
 Many as are the varieties of the Saw, the principle is the 
 same in all, and the chief distinction lies in the shape and 
 arrangement of the teeth, according to the work which they 
 have to do. "Watch-spring Saws, for example, which have to 
 cut metal, have their teeth so slight as to be hardly per- 
 ceptible, and arranged nearly in a line with each other. The 
 Fretwork Saws, which have to cut delicate patterns in wood, 
 
 J-J 
 
 SAW OP COMMON 8AW-FLY (MAGNIFIED). 
 GROOVES CUT BY SAW IN BARK. 
 
 HAND-SAW. 
 
 TENON SAW. 
 PIONEER'S SAW-SWORD. 
 
 with the slightest possible waste of material, are of the same 
 character. Then we have the long curved teeth of the 
 Circular Saws, which tear their way savagely through great 
 tree-trunks, and fill the air with clouds of sawdust. There 
 are also the Tenon Saw, with its thin blade and broad back ; 
 the pioneer's saw for cutting green wood, with its double 
 array of teeth, so as to make a wide "kerf" in which it shall 
 not be clogged ; together with many others that we cannot 
 enumerate here. 
 
 WE will now examine some Saws as found in Nature. 
 
 I need scarcely say that some of the best examples of natural 
 eaws are furnished by those insects which are known to ento- 
 mologists as Tenthredinidse, and to the general world as Saw- 
 flies. These insects are supplied by Nature with a pair of
 
 242 NATURE'S TEACHINGS. 
 
 most remarkable saws, which aid them in depositing their 
 eggs. Indeed, without these instruments, the whole race of 
 Saw-flies would long ago have become extinct. 
 
 They haunt almost every kind of tree and many plants, and 
 one valuable plant, the Turnip, is so devastated by them, that 
 whole crops are sometimes swept away. As, therefore, the 
 knowledge of the life- history of any insect will tell us whether 
 to protect or destroy it, and the best method of adopting 
 either course, we will cast a hasty glance at some of our 
 commonest Saw-flies, the instruments which they employ, 
 the mode in which they use them, and the analogies between 
 them and the saws made by the hand of man. 
 
 In the first place, it must be observed that the use of these 
 saws is to cut grooves in young bark, these grooves being the 
 depositories of their eggs. It follows, therefore, that as a 
 tolerably wide groove is needed, the saw-blade is a tolerably 
 thick one, and the teeth set on the same principle as that which 
 is employed in the saw-sword of the pioneer. When the 
 microscope is applied to the cutting instrument of the Saw-fly, 
 it reveals the fact that there are two horny saws, which work 
 alternately in their grooves, and that they are strengthened by 
 a thick plate of horn on their backs. 
 
 The system of toothing is very complicated. Not only are the 
 sides as well as the edges of the saws toothed, but each tooth is 
 furnished with smaller teeth, after the fashion of the shark's 
 wonderfully effective cutting apparatus. These subsidiary teeth 
 vary greatly in shape and size according to the species, and in 
 some cases each tooth is quite a complicated structure. In 
 Trichiosoma lucorum, for example, a bee-like insect, very common 
 upon hawthorn, the teeth are extremely beautiful. It is 
 difficult to describe them without diagrams, but I will try to 
 give the reader an idea of them.. 
 
 Each tooth is somewhat of a lancet shape, but is not termi- 
 nated by a single point. At the tip comes the secondary tooth, 
 which is conical and stands on a footstalk. The cone, however, 
 is not simple, but is made of some seven or eight cutting plates, 
 each smaller than its predecessor, and the last being a sharp 
 conical point. The reader may imagine how effective such a 
 saw would be in cutting green wood, the toothed sides and the 
 subsidiary teeth alike preventing the blades from clogging, while
 
 SAW-FLIES. 243 
 
 the alternate movement of the saws enables them to do double 
 work in the same time. 
 
 Mr. Westwood, who examined these insects very closely, 
 throws out, in his "Modern Classification of Insects," the idea 
 which forms the subject of this book. Writing of the cutting 
 weapon of the Saw-flies, he remarks that " from its admirable 
 construction it cannot be doubted that a careful examination of 
 its various modifications might furnish ideas for improved 
 mechanical instruments." 
 
 Mr. Gosse, in his " Evenings at the Microscope," points out 
 that, beautiful and elaborate as these instruments are, they are 
 but the sheaths of a still finer and more delicate pair of saws. 
 These secondary saws have only a few teeth on the edge, and 
 these near the point, whereas the sides are furnished with a 
 number of sharp blades, set on their edges, slightly over- 
 lapping each other, and directed backwards. There is a similar 
 structure on the ovipositor of the Sirex, as we shall see when 
 we come to treat of Boring Instruments. 
 
 Although the saws are made expressly so that they shall not 
 stick in the wood, there are many instances known where 
 female Saw-flies have been found dead on the branches, their 
 saws still in the last groove which they have cut. I am inclined 
 to think that these must be females which have deposited all 
 their eggs, and which have died, as do nearly all insects under 
 similar circumstances. This opinion is strengthened by some 
 observations made by Mr. J. K. Lord on the Cicada, the female 
 of which is furnished with a similar ovipositor : 
 
 " I was curious to watch the female depositing her eggs. 
 
 " She first clasps the branch on both sides with her legs, and 
 with the ends of the file very carefully slits up the bark. 
 Then, placing the instrument longitudinally, she files away 
 until she has obtained sufficient length and breadth. The 
 small teeth of the files are now used crosswise of this fissure, 
 until a trench is made in the soft pith. 
 
 " When large enough, slowly down the groove in the centre 
 of the instrument glides a small pearly egg, pointed at both 
 ends, and so transparent that the little grub within is clearly 
 discernible. Gently she lays it within its bed, and then drops 
 a thin gummy material on it, to secure it from moisture. This 
 finished, she proceeds to deposit another, and so on, until a 
 
 R 2
 
 244 NATURE'S TEACHINGS. 
 
 sufficient number are produced to fill the fissure ; then over all 
 she drags the everted bark. It is easy to perceive where the 
 Cicada has been concealing her brood, by the elevation on the 
 branch. 
 
 "In this manner she deposits about seven hundred eggs, 
 going from branch to branch, her marvellous instinct teaching 
 her to select the most suitable wood for the purpose. The time 
 occupied in constructing each nest was from fifteen to twenty 
 minutes. Her earthly mission finished, she drops, fainting and 
 exhausted, from the branch, and dies. 
 
 " The male, who is always trilling his refrain, goes on, 
 indifferent, or unconscious, that the task of his faithful spouse 
 is finished, singing even, until his time comes then he too 
 drops beside her. Thus the songs one by one cease, not only 
 the Cicada's, but all the forest choir, and give place to blasts that 
 sigh in mournful music through the leafless trees." 
 
 The Sirex and several of the larger Ichneumon-flies are often 
 found dead in like manner, and I have no doubt from the same 
 cause. An elaborate description of the beautiful double saws of 
 the Cicada is given by Mr. "Westwood in the work already 
 quoted, together with illustrations. 
 
 THE RIBBON SAW, CORDON OR BAND SAW. 
 
 PERHAPS some of my readers may be acquainted with a saw 
 which has of late years come into extensive use namely, the 
 Ribbon Saw, Cordon Saw, or Band Saw. This is an endless 
 steel band toothed on one edge, and passing over two wheels. 
 It has the advantage of being of almost any breadth, some 
 being several inches wide, while others are mere narrow 
 ribbons, barely the sixth of an inch wide. The fretwork of 
 pianos and other articles of furniture is cut almost exclu- 
 sively by the Cordon Saw. A thick piece of wood is cut 
 of the requisite shape, and the upper and under surfaces planed 
 quite true to each other. The pattern is traced on the upper 
 surface, and a very narrow Cordon Saw is then applied to it, 
 cutting completely through the thick block, and adapting itself 
 to all the intricacies of the pattern. The block is then cut into 
 thin slices, so that a number of pieces of fretwork can be made
 
 THE RIBBON SAW. 
 
 245 
 
 with comparative ease. To those who have been accustomed to 
 cutting fretwork with the slow hand- saw, the Cordon Saw is 
 simply fascinating, the slender steel ribbon cutting through the 
 wood with wonderful rapidity and very little sound. 
 
 BEAUTIFUL as this invention is, it was long ago anticipated 
 in Nature ; and the Cordon Saws, which we shall now see, are 
 armed with teeth many more in number, and far more compli- 
 cated in detail, than those of any saw made by the hand of 
 man. I allude to the Tooth-ribbon possessed by many of our 
 common molluscs, such as the Limpet, the Whelk, the Peri- 
 winkle, the Slug, &c. The last mentioned of these creatures 
 possesses a natural Cordon Saw with nearly twenty- seven thou- 
 
 PORTION OF TOOTH-RIBBON OP WHELK 
 (HIGHLY MAGNIFIED). 
 
 RIBBON OK CORDON SAW. 
 
 sand teeth, and scarcely a tooth that is not elaborately cut into 
 secondary teeth. 
 
 As all these creatures have their teeth differently formed and 
 set, according to the species, it will be impossible to describe 
 them separately. I will therefore restrict myself to the Tooth- 
 ribbon of the common Whelk, a specimen of which is now 
 before me. When viewed through the microscope, it is found 
 to consist of a flat membranous ribbon, on which are set three 
 rows of teeth, those of the outer row being hooked, and those 
 of the inner one plain. 
 
 The outer teeth are formed somewhat like the Hebrew 
 letter 3, both of the points being very sharp, and the central 
 part being furnished with two secondary teeth. All these
 
 246 NATURE'S TEACHINGS. 
 
 teeth overlap each other, so that some care in manipulation is 
 required before their form can he made out. 
 
 Along the centre of the tooth-ribhon run successive rows of 
 small, lancet-shaped teeth, six in a row, so that altogether there 
 are eight teeth in each row. 
 
 The power of this weapon is astonishing. Some of my 
 readers may be aware that Whelks are carnivorous beings, and 
 that they swarm upon any dead animal which may be found in 
 the sea. Indeed, when we hear of the mutilations which take 
 place on dead corpses after a shipwreck, and which are generally 
 attributed to fishes, we may make up our minds that the real 
 delinquents are the Whelks, together with various Crustacea, 
 and that the principal instrument in effecting such mutilation 
 is the tooth-ribbon which has just been described. 
 
 The Whelks feed largely upon other molluscs, in spite of 
 their shells. A periwinkle has a peculiarly hard shell, and yet 
 Mr. Rymer Jones saw a Dog-whelk (Purpura lapillus) eat a 
 periwinkle in a single afternoon, first boring a hole through its 
 shell with the tooth-ribbon, and then, by means of the same 
 weapon, licking it, so to speak, out of its shell. 
 
 The Periwinkle itself has a similar tooth- ribbon, and so have 
 the Limpet and the pretty Top-shell. These creatures are 
 vegetarians, but they are furnished with similarly armed 
 tongues, and use them in the same way. Nothing is easier 
 than to see these tooth-ribbons in use. When sea-water is 
 kept in glass vessels, a green flocculence is sure to collect upon 
 the glass and to render it opaque. 
 
 If, however, a few Periwinkles and Top-shells are placed in 
 the tank, they immediately set to work at this confervoid growth, 
 and by means of the tooth-ribbon sweep off the green sub- 
 stance, leaving the glass nearly clean. This movement can be 
 seen with the naked eye, but with the assistance of a pocket 
 lens the action of the tooth-ribbon is beautifully shown as it 
 issues from its socket, makes its sweeping curve, with the tiny 
 teeth glittering like specks of glass, and then is withdrawn 
 ready for another sweep. 
 
 Should sea-water and living Periwinkles not be easily 
 obtained, the same phenomenon may be observed in fresh 
 water, and with the common Pond-snail, which may be caught 
 by thousands in any stream and in most ponds.
 
 THE CIRCULAR SAW. 
 
 247 
 
 THE CIRCULAR SAW. 
 
 IN one sense the Cordon Saw is a Circular Saw, but we now 
 restrict the name to the tool which has a circular blade, more 
 or less deeply toothed on the edge. The largest and coarsest 
 of these saws are of enormous diameter, have teeth several 
 inches in length, and can cut a large tree-trunk asunder in a 
 wonderfully short time. 
 
 There is a huge saw of this kind in Chatham Dockyard. 
 It is kept in a sort of cellar covered with flap doors, where it 
 really has the air of some dread monster lying in wait for prey. 
 A tree-trunk is brought for it to feed upon. The doors slowly 
 open, the saw emerges, revolves so fast that the eye cannot 
 detect the teeth, seizes on the tree-trunk, tears its way through 
 
 SAWYEB-BEETLB. 
 
 CIRCULAR SAW. 
 
 with a scream and roar, and then sinks back into its cellar. 
 I have often watched this saw in action, and have never been 
 able to get over a kind of feeling that it was alive. 
 
 Now, if we suppose the saw to be pierced in the centre, and 
 to have teeth on the inside instead of the outside, it would be 
 equally efficacious ; and, indeed, we have several tools used for 
 cutting iron bars or pipes, that are constructed on a similar 
 principle, though the cutting tooth revolves slowly instead of 
 rapidly, and is urged by a lever handle. 
 
 THERE is in Nature a Circular Saw of just such a character, 
 the teeth having their points directed inwards, and not out- 
 wards.
 
 248 NATURE'S TEACHINGS. 
 
 In tropical America there are several large beetles which, 
 like our Stag-beetle, feed upon the sap of trees, and obtain it 
 by wounding the young branches with their jaws. 
 
 One or two of them are pointed out as having the power of 
 cutting a branch completely off by seizing it in their deeply 
 toothed jaws, and flying round and round the branch so as to 
 convert themselves into a circular saw. The late Mr. Waterton 
 showed me a branch which had fallen on his head, and which 
 was said to have been cut off by the Sawyer-beetle, as the 
 insect is called. He did not actually see the insect at work, 
 but he had no doubt that the natives were right who told him 
 that it was the work of beetles' jaws. Certainly the cut looked 
 exactly as if it had been made in the way described. The 
 branch was somewhat thicker than an ordinary walking-stick. 
 
 The truth of this statement has often been denied, but I 
 have ascertained from personal observers that it is literally 
 true. A loud noise is produced by the operation, and, as the 
 female is never seen to perform it, the general idea is that it is 
 a call to its mate.
 
 TOOLS. 
 
 CHAPTER ITT. 
 
 BORING TOOLS. STRIKING TOOLS. GRASPING TOOLS. 
 
 'fie Bradawl and the Gimlet defined. Natural Bradawls. The Ichneumon-flies. 
 A Pimpla engaged in Boring Operations. Principle of the Wedge. 
 Resisting Power of Earth. Pitching Tents in Sand. Hidden Forces of 
 Nature. The Aloe-leaf and its Growth. A cruel Punishment. Natural 
 Gimlets. Ovipositor of the Sirex, and its Analogy to a Carpenter's Gimlet. 
 The Auger and the Gad-fly. Striking Tools. The Hammer. Origin and 
 Development of the Tool. The Axe. The Woodpecker and the Nuthatch. 
 The Ivory-billed Woodpecker. Grasping Tools. Pincers and their Modi- 
 fications. Sugar-tongs and Coal-tongs. Natural Pincers. Bivalve Mol- 
 luscs. The Clam's Grip. The Earwig. Crab and Lobster Claws. 
 
 BORING TOOLS. 
 
 NEXT in importance to the edged tools which cut, come the 
 pointed tools by which holes can be bored. We have 
 an abundance of such tools, but they can all be reduced to 
 two types, namely, those which, like the Bradawl, are forced 
 between the fibres, and those which, like the Gimlet, cut away 
 the material as they pass through it. 
 
 They may, again, be shown to be different modifications of 
 a single principle i.e. that of the Wedge or Inclined Plane, 
 which, as has already been shown, is identical with that of the 
 screw. The Bradawl is, in fact, a sharp wedge, which is forced 
 through the fibres, sometimes being merely forced between 
 them, and sometimes cutting them, and thus forcing aside the 
 severed fibres. 
 
 A natural example of the Bradawl is to be found in various 
 Ichneumon-flies, especially those with very long ovipositors, 
 which are intended for boring into wood. 
 
 All the Ichneumons are parasitic, laying their eggs in the 
 larvae of other insects, mostly those of moths and butterflies.
 
 250 NATURE'S TEACHINGS. 
 
 Generally these larvoe exist in the open air, and the Ichneumon- 
 fly has little difficulty in piercing them. But there are some 
 which live either in wood or underground, and, in order to 
 reach their hidden bodies, the Ichneumon is furnished with an 
 extremely long and sharply pointed ovipositor. 
 
 This wonderful instrument is not so thick as an ordinary 
 horsehair, although it is composed of three portions, and 
 seems to be utterly inadequate to the task which it has to per- 
 form. Ascertaining by its instinct the exact locality of the 
 caterpillar which it desires to pierce, the Ichneumon-fly clings 
 firmly to the tree, bends the body so as to bring the point of 
 the ovipositor against the wood, and, by moving the abdomen 
 backwards and forwards, gradually works the instrument into 
 the wood, sometimes piercing it to a considerable depth. 
 
 Mr. "Westwood once saw an Ichneumon-fly thus boring its 
 way into a dry post, the wood of which must have been very 
 hard. When she had bored far enough, she partially withdrew 
 the ovipositor, and then re-plunged it into the hole that she had 
 made, as if she were depositing eggs. While engaged in this 
 operation, she stood very high on her long legs, resting only on 
 the extremities of the feet. She belonged to the genus Pimpla. 
 
 THE principle of the Wedge or Inclined Plane is admirably 
 shown by objects which we pass unheeded every day, and yet 
 afford wonderful examples of the power of the wedge. 
 
 Scarcely any vegetable growth is so plentiful as grass, which 
 has been used in that sense by the highest of all authorities, 
 " which to-day is, and to-morrow is cast into the oven." Grass 
 forces its way everywhere not only in cultivated grounds, but 
 in the wildest of lands, where there is scarcely any nurture for it. 
 Even among the habitations of mankind the grass will have its 
 way, and clothes deserted housetops with verdure, and forces 
 itself between the stones that pave neglected streets. 
 
 Place side by side some of these stones, together with a very 
 young and tender Grass-blade, and it will seem to be impos- 
 sible that so fragile an object should be able to exert any influ- 
 ence on the solid stone. Let any one try to push a sharp 
 skewer between the stones, and he will find that he has to 
 exert power sufficient to crush a thousand grass-blades. Yet 
 these slight and delicate objects will force themselves between
 
 THE WEDGE. 
 
 251 
 
 the stones, and sometimes to such an extent as to cover the 
 whole roadway with verdure. 
 
 The force which is employed is simply marvellous, and can 
 only be appreciated by those who know the resisting power of 
 earth, however dry and loose it may be. Even sand has so 
 strong a resistance that tents can be pitched in the desert with- 
 out difficulty. Of course the ordinary tent-peg would be use- 
 less, but the desert dwellers can pitch their tents with perfect 
 security. They fasten the tent-rope to a branch or piece of 
 bush, scrape a hole in the sand, put the bush into the hole, 
 
 OEASS-BLADES. 
 
 cover it up again, and it will withstand almost any strain, 
 though it be only covered with a few inches of sand. 
 
 When miners blast rocks with gunpowder, they take advan- 
 tage of the resisting power of sand. They bore a suitable hole, 
 place a charge of gunpowder at the bottom, and then merely 
 pour loose sand into the hole until it is filled. When the 
 powder explodes, the rock or coal is shattered to pieces, but the 
 sand is not blown out of the hole. This operation is called 
 " tamping." 
 
 Every one, again, knows how firm are gate-posts, and how 
 they resist the weight, jarring, and leverage of a heavy gate, 
 all because they are sunk a little way into the earth. 
 
 Considering, therefore, that such fragile things as young 
 grass-blades can force their way through the superincumbent 
 weight, we can but be amazed at the aggregate of active force 
 which is in full operation in every pasture field and garden 
 lawn. 
 
 As far as I know, not being much of a botanist, every seed 
 that springs up does so on the wedge principle, though the form 
 of the wedge may be varied.
 
 252 NATURE'S TEACHINGS. 
 
 A terrible example of the force which is exercised by this 
 principle among the vegetables is shown in some parts of 
 the world where the Aloe flourishes in a wild state. In our 
 colder clime the Aloe, though it does live in the open air, is a 
 slow-growing plant. But, in its own land, it shoots up with 
 a surprising vigour, and its sharply pointed and saw-edged 
 leaves are said to grow to the extent of six inches in a single 
 night. 
 
 Taking advantage of this rapid, and, at the same time, powerful 
 growth, the natives, when they want to punish a man with 
 more than ordinary severity, tie him hand and foot, and bind him 
 to the earth just over a sprouting aloe plant, and leave him 
 there. In twenty-four hours the man is nearly certain to be 
 dead, the aloe-leaf having forced itself completely through his 
 body. Or, if he be not actually dead, he lives in frightful 
 tortures, which are continually increased by the flinty point 
 and notches forcing themselves slowly, but surely, through the 
 body. 
 
 FOR an example of the Gimlet we may take the ovipositor of 
 the Sirex, an insect which I believe has no popular name. It 
 is coloured much after the same manner as the hornet, and is 
 often mistaken for that insect by those who are not versed in 
 entomology. And, as its long and straight ovipositor is gene- 
 rally taken for a hornet's sting, the insect assumes a double 
 terror to the ignorant. 
 
 Now, the real fact is, that in its larval stage of existence the 
 Sirex feeds upon the wood of the fir-tree a diet which, to 
 our ideas, is about as unsatisfactory as can well be imagined. 
 In order that the young Sirex may be within reach of food, the 
 egg must be introduced deeply into the body of the tree, and, 
 for the egg to be so received, a channel must be cut for it. 
 
 This is done by means of the marvellously formed ovipositor. 
 Many admirable descriptions have been given of the head of 
 this instrument and its boring powers, but I am not aware that 
 any one has noticed the secondary cutting L la les that are set 
 along the shaft of the principal borer, and which answer exactly 
 the same purpose as the spiral cutting edge of the gimlet or 
 auger. 
 
 Not being desirous of repeating my own observations in dif-
 
 BORING TOOL OF THE SIREX. 
 
 253 
 
 ferent words, I transfer to these pages a short account of the 
 ovipositor of the Sirex, as examined by me when writing my 
 work on British Insects, entitled " Insects at Home," and pub- 
 lished by Messrs. Longmans and Co. : 
 
 " I very strongly recommend any of my readers who may 
 obtain a female Sirex to disengage the actual borer from its 
 two-bladed sheath, and examine it with the aid of a microscope. 
 A. half-inch object-glass will give quite a sufficient power. 
 
 fESTKUS. 
 BORING TOOL OP BIBKX AND LARVA. 
 
 BRADAWL8. 
 
 " It is straight, stiff, and elastic, as if made of steel, and, if 
 bent, will spring back to its proper form with the elasticity of 
 a Toledo rapier. 
 
 "But the borer possesses an auxiliary cutting apparatus 
 which places it far above the rymer in point of efficacy. Even 
 with an ordinary magnifying lens, it is easy to see that the end 
 of the borer is developed into a sharp head, very much 
 resembling that of a boarding-pike, and that the outline of the 
 shaft is broken into a series of notches. 
 
 " The half-inch glass, however, discloses a marvellous 
 example of mechanical excellence. The head of the borer is 
 then seen to be armed with long, sharp teeth, slightly curved 
 inwards, and acting just as does the carpenter's ordinary centre- 
 bit. 
 
 " So much for the head of the borer : we will now turn to 
 the shaft.
 
 254 NATURE'S TEACHINGS. 
 
 "It appears that, in order to make a clean-cut hole for the 
 reception of the egg, the shaft of the borer has to finish the 
 task which the head begins. Accordingly, it is armed on each 
 of its sides with a series of hard, sharp-edged ridges, running 
 diagonally across it, and acting exactly as do the sharp ridges 
 of a coffee-mill." 
 
 In point of fact, the ovipositor of the Sirex is the natural 
 type of the improved gimlet of the present day. Instead, how- 
 ever, of having a single, spiral, sharp-edged groove running 
 along the whole length of the shaft, it has a series of small, 
 sharp blades, set exactly in the same line as is taken by the 
 spiral groove, and acting in exactly the same manner i.e. by 
 cutting out successive portions of wood, and, by the diagonal posi- 
 tion of the blades, throwing out the debris as fast as it is cut. 
 
 I cannot but think that, if any modern tool manufacturer 
 could take as his model the saw-like ovipositor of the Ten- 
 thredinidae, and the auger-like ovipositor of the present insect, 
 he would produce a series of most valuable implements, possess- 
 ing powers far beyond those of ordinary tools. 
 
 These short blades are arranged just like the " studs " on 
 modern shells, and very much resemble them in shape, though 
 not in material. 
 
 THE Auger finds also a natural representative in the 
 ovipositor of an insect. 
 
 That of the common Gad-fly (CEstrus lovis) is most beauti- 
 fully constructed. It is tubular in form, and is of a telescopic 
 nature, consisting of four tubes of different sizes, the smaller 
 fitting into the larger just as is done with the joints of a 
 common telescope, or those of a Japanese fishing-rod. 
 
 The end of the ovipositor is developed into little projections, 
 some of which are armed with hard, sharp points, which act 
 exactly like the cutting edge of the auger. This elaborate 
 appliance is necessary on account of the thick, tough skin of 
 the ox, which the Gad-fly has to penetrate before it can deposit 
 its eggs. Perhaps the reader may be aware of the fact that 
 the modern system of cutting channels in stone with the 
 diamond point, as was so well exemplified in the Mont Cenis 
 Tunnel, is but an imitation, and an imperfect one, of the method 
 adopted by the Gad-fly. We shall soon recur to this instrument.
 
 STRIKING TOOLS. 255 
 
 STRIKING TOOLS. 
 
 IF we search the records of antiquity as left by races of men 
 that have for countless ages vanished from the face of the earth, 
 we shall find that in some shape or other the Hammer was a 
 tool in constant use, and that in principle, though not in mate- 
 rial, there was no difference between the Hammer of the Stone 
 Age and that of a blacksmith of the present day. 
 
 The development of the instrument can easily be traced, 
 especially as it is a tool which does not admit of much 
 elaboration. 
 
 The original hammer was evidently a simple stone, and 
 answered equally as a tool and a weapon. As, however, man 
 progressed towards civilisation, he found that the stone itself 
 was insufficient for his needs, and that he required much more 
 force. The most obvious mode of doing so was to take a larger 
 stone, but this expedient soon became valueless, inasmuch as a 
 large stone was a cumbrous instrument to handle, and could not 
 be directed with any certainty or delicacy. 
 
 The principle of the lever was then applied to the stone, 
 which was affixed to a handle, and thus became elevated into 
 the rank of a comparatively civilised tool. Sometimes the stone 
 had a hole bored through it, into which the handle of the 
 hammer was inserted, as is the case with most of our present 
 hammers and pickaxes. Sometimes the end of the handle was 
 enlarged, and the stone thrust through it, as is now done with 
 the axes of Southern Africa. Sometimes a long, flexible rod 
 was used by way of handle, the centre of it taking two turns 
 round the stone, and the ends being lashed together. Handles 
 thus made may be seen in any blacksmith's forge of the present 
 day. 
 
 The tool thus made was soon developed into various forms 
 for different uses. By lengthening and pointing the head, it 
 became a pick for loosening the earth. By widening and flat- 
 tening the head, it became a hatchet ; and, by performing the 
 same alteration in the pickaxe blade, it became an adze. I 
 possess a singularly ingenious tool from Borneo, in which the 
 head is movable, so as to be used as a hatchet or adze at 
 pleasure. 
 
 In Demmin's "Weapons of War" many such hammers and
 
 256 
 
 NATURE S TEACHINGS. 
 
 axes are figured. One of them is very remarkable. It is an 
 ancient war-hammer made of black stone, and is shaped 
 exactly like a pickaxe, except that one end of the head is 
 carved into a semblance of some animal's head. The handle is 
 passed through an oval hole in the centre, just like our pick- 
 axes of the present day. This remarkable example of the art 
 of the Stone Age was found in Russia. The head was nearly 
 a foot in length. 
 
 NATURE possesses many examples of this principle, of which 
 I have chosen two, namely, the Woodpecker and the Nut- 
 hatch. 
 
 The wonderful power of beak possessed by both these birds 
 is familiar to every one, but it is not so generally known that 
 
 XTJTHATCH. 
 
 WOODPECKER. 
 
 they do not merely peck after the usual fashion among birds, 
 i.e. delivering the stroke with the force derived from the neck 
 alone. These birds have an additional leverage. Grasping the 
 tree firmly with their feet, they not only peck, but swing their 
 whole bodies with each stroke, bringing their weight to bear 
 upon the object. They thus convert themselves into living 
 hammers, the feet acting the part of the human hand, the 
 body of the bird being analogous to the handle of the hammer, 
 and the head playing the same part in both cases. 
 
 In England these birds are not known as well as they ought 
 to be, partly because they are both very shy creatures, and 
 partly because the gradual extinction of forests has deprived 
 them, and especially the "Woodpecker, of their undisturbed 
 homes. Yet those who are early risers may see both birds in
 
 THE NUTHATCH AND WOODPECKER. 
 
 places where their presence is quite unsuspected, except, per- 
 haps, by those who can recognise the signs which they have left 
 behind them. 
 
 There is a common saying to the effect that " a carpenter is 
 known by his chips," and the proverb is equally true of the 
 Nuthatch and the Woodpecker. Nutshells scientifically split 
 asunder, and jammed into the rough bark of a tree- trunk, betray 
 at once the Nuthatch to the eye of a naturalist ; while an accu- 
 mulation of shattered bark, splinters of wood, and similar debris 
 announces, in equally bold type, that a Woodpecker has been at 
 work. 
 
 The power of the Woodpecker's beak may be gathered from 
 Wilson's well-known account of an Ivory-billed Woodpecker, 
 which he had wounded and was trying to rear. While staying 
 at an hotel, he locked the bird in his room, and, on returning 
 within an hour, found an astonishing state of things. 
 
 " He had mounted along the side of the window, nearly as 
 high as the ceiling, a little below which he had begun to break 
 through. The bed was covered with large pieces of plaster, 
 the lath was exposed for at least fifteen inches square, and a hole 
 large enough to admit the fist opened to the weather boards, 
 so that in less than another hour he would certainly have suc- 
 ceeded in making his way through. 
 
 " I now tied a string round his leg, and, fastening it to the 
 table, again left him. I wished to preserve his life, and had 
 gone off in search of suitable food for him. As I re-ascended 
 the stairs, I heard him again at work, and on entering had the 
 mortification to perceive that he had almost ruined the mahogany 
 table to which he was fastened, and on which he had wreaked 
 his whole vengeance." 
 
 The beak of the Woodpecker was employed upon its new 
 master quite as forcibly as upon walls and furniture, but 
 Wilson was of too generous a nature to resent his injuries, and 
 lamented sincerely when the bird died. 
 
 The reader will probably observe that the Hammer which 
 has been given as an illustration of this principle is- the ordi- 
 nary geologist's hammer, and that it has been selected because 
 its head is . so formed that one end can be employed for the 
 usual tasks of a hammer, while the other end, with its slight 
 curve and sharp point, is, in fact, a sort of pickaxe, and used 
 
 8
 
 258 NATURE'S TEACHINGS. 
 
 for the same purposes. Indeed, this instrument is an almost 
 exact reproduction of the stone hammer which has already 
 been mentioned, the blunt end being represented by the carved 
 head, and the sharp end by the pickaxe point. 
 
 GRASPING TOOLS. 
 
 ALREADY we have spoken of the Shears and Scissors, together 
 with their mode of action and dependence upon leverage. 
 We now come to a set of tools which, although equally 
 dependent on leverage, develop that power by grasping instead 
 of cutting. Without these tools, the arts and sciences could 
 have scarcely made themselves felt, as there are but few 
 manufactures in which the artificer does not require a grasping 
 power far superior to that of the human hand. 
 
 Perhaps the enormous power of the Pincers is never shown 
 to better advantage than in the great iron-works, where enor- 
 mous masses of white-hot metal have to be brought under the 
 blows of the steam hammer. I do not know of anything which 
 affords a more imposing realisation of the Divine command that 
 man is to subdue the earth as well as to replenish it. There is 
 the vast hammer, striking blows which are felt throughout a 
 large area as if a succession of earthquakes had been let loose. 
 In the furnace there is an enormous mass of iron, heated to 
 such a degree that an unpractised eye could no more dare to 
 look at it than to stare a midsummer sun out of face. 
 
 Where are the armies who are to cope with such forces ? 
 A few stalwart and grimy men come forward, each man with 
 a curious but unmistakable air of one who wages a war of 
 giants. The furnace door is opened, and out rushes a blinding 
 light which strikes on the eyeballs like a shock of electricity. 
 The men seize the handles of an enormous pair of Pincers, 
 suspended in the middle by a chain, and though no unpractised 
 eye can distinguish the glowing iron from the enveloping fire, 
 they run the Pincers into the furnace, seize the iron, swing it 
 to the anvil, and turn it this way and that way as easily as if 
 it were a feather, while the blows of the gigantic hammer 
 descend upon it, enveloping them in a torrent of sparks which 
 spurt as if they were mere splashes of water, and seem to do 
 them no more harm.
 
 PINCERS. 
 
 259 
 
 Taking the minor exposition of the Pincers principle and 
 their use, we may mention the ordinary Pincers which are mostly 
 used for drawing nails. Then there are the smaller Pincers 
 called Pliers, all of which are constructed on the same principle, 
 and the chief of which are the Round-nosed Pliers, the Long- 
 nosed Pliers, and the Gras Pliers. Sometimes a mixture of the 
 Hammer and the Pincers is ingeniously contrived, as in the 
 tool which is represented on the right hand of the illustration. 
 
 Then we have the still smaller and feebler Pincers of civilised 
 life, such as the Sugar-tongs and the ordinary Coal-tongs of 
 
 MUSSEL-SHELL. 
 EARWIG. LOBSTBR-CLAW. 
 
 SUGAB-TONGS. 
 
 our firesides. Anatomists could have had no practical existence 
 without the Pincers, of which their beautifully constructed and 
 much-elaborated forceps are but variations. 
 
 Take, again, the dentist, with his series of shining instru- 
 ments, which he so carefully keeps out of sight until he has 
 got his patient safely in that awful chair, and which glide, as 
 by a conjurer's trick, empty into an open mouth, and return 
 in a few seconds with a tooth between their polished jaws. 
 
 ALL these instruments have their parallels in Nature, and 
 in many instances the natural pincers might supply useful hints 
 to modern tool-makers. 
 
 In the left-hand upper corner of the illustration is shown the 
 common fresh-water Mussel, which is so plentiful in almost all 
 our rivers and many of our ponds. Its scientific name is Unio 
 margaritiferm. The latter title, which signifies " pearl- 
 
 s 2
 
 260 NATURE'S TEACHINGS. 
 
 bearing," is given to it because it furnishes the British pearls 
 which were at one time so highly valued. 
 
 Like other bivalve molluscs, this Unio has the two halves 
 of the shell fitting quite tightly upon each other, and, when 
 they are drawn together by the contraction of the internal 
 muscles, they can give a very severe pinch. In many un- 
 civilised parts of the world the natives take advantage of 
 this property, and use them as tweezers, chiefly for the pur- 
 pose of pulling out hairs which they are pleased to think are 
 not needed. 
 
 I need not state that with all bivalves the power is increased 
 in proportion to the size of the shell. Even an Oyster can 
 pinch most severely, while the Giant Clam, the shell of which 
 weighs some four hundred pounds, could nearly take off a man's 
 leg if it seized him. 
 
 Mr. J. Keast Lord, in his "Naturalist in British Colum- 
 bia," relates an amusing story that was told to him by an old 
 settler respecting the power of the Clam's grip : 
 
 " You see, sir, as I was a-cruising down these flats about 
 sun-up, the tide jist at the nip, as it is now, I see a whole 
 pile of shoveller-ducks snabbling in the mud, and busy as dog- 
 fish in herring time. So I creeps down, and slap I let 'em 
 have it. Six on 'em turned over, and off went the pack, 
 gallows scared, and quacking like mad. 
 
 "Down I runs to pick up the dead uns, when I see an 
 old mallard a-playing up all kinds o' antics, jumping, backing, 
 flapping, but fast by the head, as if he had his nose in a steel 
 irap; and when I comes up to him, blest if a large Clam 
 hadn't hold of him, hard and fast, by the beak. 
 
 " The old mallard might ha' tried his hardest, but may I never 
 bait a martin-trap again if that Clam wouldn't ha' held him agin 
 any odds till a tide run in, and then he'd ha' been a gone 
 shoveller sure as shooting. So I cracked up the Clam with 
 the butt of my old gun, and bagged the mallard." 
 
 Of course the reader will remember that this was only an 
 ordinary Clam, and not one of the giant race. 
 
 BELOW the shell are two very perfect instances of natural 
 Pincers, each acting in a different manner, but on the same 
 principle.
 
 PINCERS OF EARWIG. 261 
 
 The Earwig is too familiar to need much description, but I 
 may as well state that its pincers are not primarily intended as 
 weapons, although they can be so used on occasion. (I was 
 about to say, at a pinch, but refrain.) They resemble our ordi- 
 nary pincers in that both blades move equally, and they are so 
 completely under the control of their owner, that the insect 
 uses them with a delicacy of touch that a lady's fingers could 
 hardly surpass. They are really tools, and not weapons, and 
 are employed for the purpose of folding the wide and delicate 
 wings under the tiny elytra. 
 
 There is another insect called the Scorpion -fly (Panorpa), 
 the male of which is furnished with a pair of pincers at the 
 end of a long and flexible tail, articulated just like the tail of a 
 scorpion, and moved in exactly the same manner. It is but a 
 little insect, but its gestures are so menacing as it flourishes 
 its tail about, that non-entomologists may well be pardoned for 
 being afraid of it. Moreover, small as are the pincers, they 
 really can give a smart nip, and make themselves felt on the 
 human skin. 
 
 IF we want examples of exceedingly powerful pincers, we 
 need only go to the Lobsters and Crabs, especially to the 
 latter, whose claws are often of enormous thickness in propor- 
 tion to the size of the animal. All those who have visited the 
 seaside know how severe is the pinch of the common Green 
 Crab, comparatively small though it be, and the same may be said 
 of the river crayfish, which is, in fact, a lobster in miniature. 
 
 As to the lobster itself, fishermen are so well acquainted with 
 the power of its claws, that they tie them together with string 
 as soon as the animal is caught. Formerly they used to 
 " P e g " them, i.e. drive a wooden peg into the joint so as to 
 prevent it from moving. This custom, however, is now pro- 
 hibited by law on account of its cruelty. 
 
 The power of the Crab's claws is so great that a bite from a 
 large Crab will inflict a severe injury, and render a hand help- 
 less. It has more than once happened that men who have been 
 feeling for Crabs in the recesses of the rocks at low water have 
 been seized, and seriously imperilled, not being able to release 
 themselves from the gripe. 
 
 Indeed, it is said that there have been instances where the
 
 262 NATURE'S TEACHINGS. 
 
 Crab has held so tightly, that the man has been drowned by the 
 returning tide, no one having come to his assistance. I am, 
 however, inclined to doubt this statement, thinking that the 
 Crab would not be likely to remain in its hiding-place very 
 ong after the water came up. Still, that such an idea should 
 be currently believed in many parts of England shows the 
 estimation in which the gripe of the Crab's claw is held.
 
 TOOLS. 
 
 CHAPTER IV. 
 
 POLISHING TOOLS. MEASURING TOOLS. 
 
 Files and Sand-papers. The Sheffield File and ita Structure. The Equisetum, 
 Mare's Tail, or Dutch Rush. Beauty of its Surface when seen through the 
 Microscope. Sand-paper. Skin of Dog-fish, Skate, and Shark. Skate-skin 
 used for Sword-handles. Distinction between the File and Sand-paper. 
 Measuring Tools. The Plumb-rule and the Level. Their Use in Tunnelling. 
 The Measure and its Uses. The Two-foot Rule and the Tape Measure. 
 Ovipositor of Gall-fly. Tongues of the Woodpecker, Wryneck, and Creeper. 
 The Spirit-level arid its Uses. Theodolite and Callipers in Nature and Art. 
 The Contouring-glass. Pincers of Earwig again. Jaws of Insects. 
 The great Sialis of Columbia. 
 
 FILES AND SAND-PAPERS. 
 
 TTAYINGr now examined the analogies between the cutting, 
 boring, striking and grasping tools of Nature and Art, 
 we come to those finishing tools which smooth and polish the 
 surface. 
 
 The first is the File, an instrument which needs but little 
 description. It consists of a surface of hardened steel, broken 
 up into rough-edged teeth of infinite variety, according to the 
 work which the file has to do. It is rather remarkable, by the 
 way, that at present the English files are infinitely superior to 
 those produced in any other part of the world ; that their teeth 
 are all made by hand ; and that a genuine Sheffield file will first 
 cut its way through a piece of iron in half the time that would 
 be occupied by a file of any other nation, and then would easily 
 cut its antagonist in two. 
 
 As long as the File is intended to work upon metal, there is 
 little difficulty in its manufacture, except that no machinery 
 has yet been invented which can give the peculiar edging of
 
 264 NATURE'S TEACHINGS. 
 
 the ridges, and to which is owing the unmistakable " bite " of 
 a real English file. 
 
 But there are occasions when the hand of the most cunning 
 file-maker is baffled, and when it is necessary to cut files so 
 delicate that the unaided human eye cannot trace their teeth. 
 Art, therefore, has recourse to Nature, and the cabinet-maker, 
 who cannot obtain any file made by human hands which will 
 answer his purpose in the higher branches of his trade, makes 
 great use of the " Dutch Rush," as he calls it. It is not a rush 
 at all, but simply a species of Mare's Tail, or Equisetum, a 
 plant which fills in profusion almost every marshy spot in 
 England. 
 
 The peculiar fitness of the Equisetum for this purpose 
 cannot be appreciated even by those who use it until it has 
 
 EQUISETUM. 
 
 been viewed under the microscope. I have now before me a 
 small piece of Equisetum, placed under a half- inch power, and 
 viewed by direct illumination, it being treated as an opaque 
 object. 
 
 The microscope reveals at a glance the source of the power 
 which the ingenuity of man has taken advantage of. The 
 surface of the Equisetum is seen to be composed of myriads of 
 tiny parallel ridges, each ridge bristling with rows of flinty 
 spicules, looking very much like the broken glass upon the top 
 of a wall. Minute as they are, these spicules can do their 
 work, and they enable the joiner to finish off" work in a manner 
 that could not be accomplished by any tool made by human 
 hands. 
 
 I find, by recent inquiries, that modern joiners scarcely, if 
 ever, use the Equisetum, preferring emery-paper as cheaper 
 and more expeditious, and knowing that the popular eye is not 
 able to appreciate the difference of the surface obtained by
 
 SAND-PAPER. 265 
 
 the Equisetum from that which is given by the finest emery- 
 paper ever made. Wood-carvers, however, if they be of the 
 conscientious kind, and love their work for its own sake, adhere 
 to the Dutch Rush, and are all the happier for it. 
 
 PASS we now to the coarser kinds of polishers, the chief of 
 which is popularly known as Sand-paper, and is made by 
 coating some tissue with glue, and scattering upon it sand of 
 different qualities, according to the work to be done. Some- 
 times, when the work is rough, the sand is large, rough, and 
 coarse, and sometimes, when the work is fine, the sand is so 
 carefully sifted before it is scattered on the glued paper, that 
 there is little distinction between the sand-paper and emery - 
 
 DOO-FISH SKIN, MAGNIFIED. 6AND-PAPBR. MAGNIFIED. 
 
 paper. Linen, by the way, is generally used instead of paper, 
 as being more enduring, less liable to crack, and capable of 
 being folded so as to obtain access to crevices which paper could 
 not touch. 
 
 AGAIN in Nature we find a parallel, and the coarse Sand- 
 paper of modern Art has long been anticipated in the scale- 
 clad skins of many fishes. 
 
 The accompanying illustration is taken from the skin of a 
 Picked Dog-fish found by myself lying dead on the rocks in 
 Bideford Bay. I cut off a piece for transmission to the 
 draftsman, and found that not only did it feel exactly like 
 cutting through a piece of very common sand-paper, but that it 
 blunted the edge of a new knife in exactly the same manner as 
 would have been done by the roughest of sand-paper. 
 
 This kind of skin is common to all the shark tribe (including 
 the Dog-fishes, which are but sharks in miniature), and to the
 
 266 NATURE'S TEACHINGS. 
 
 Skate, Saw-fish, &c. I have now before me a small, but perfect 
 example of the Saw-fish, the surface of which is covered 
 with flinty scales like those of the Dog-fish, but very much 
 smaller, requiring the aid of a magnifying lens to distinguish 
 them. Even to guess at the number of them is impossible, 
 for they cover the whole of the body, and extend to the very 
 end of the beak, in some places glittering in a strong light as if 
 pounded glass had been sprinkled all over the fish. One of the 
 most interesting points in their structure is the manner in 
 which they reach the rounded jaws, and there become con- 
 verted into teeth powerful enough to crush the animals on 
 which the fish live. The structure of these jaws will be 
 explained in a future chapter. 
 
 Some of the skates and sharks have these scales of great 
 size, so as to show their formation almost without the aid of a 
 magnifying-glass. This is the case with a species of skate, the 
 skin of which is used by the Japanese for wrapping round the 
 handles of their best swords, and which is greatly valued by that 
 nation, the sword being an almost sacred article in the eyes of 
 a Japanese. 
 
 There is a well-known museum in which these swords are 
 labelled as having handles of "granulated ivory." Now, in 
 the first place, there is no such thing as granulated ivory ; and, 
 in the next, a mere glance ought to tell the observer that 
 the so-called ivory is a skin of some sort, worked upon the 
 handle while wet, and kept in its place by copper studs. Even 
 the junction of the edges is perceptible, and yet the authorities 
 of the museum in question, although they have been repeat- 
 edly corrected, still persist in calling the skate-skin by the 
 absurd title of granulated ivory. 
 
 However, if ivory could be granulated, it would certainly 
 look very much like the skate-skin. When examined closely, 
 the scales, whether of Dog-fish, Skate, Shark, or Saw-fish, are 
 seen to resemble hexagonal cones, not coming quite to a 
 point, but truncated, so as to have an hexagonal flattened tip. 
 They are almost of a flinty hardness, especially at their tips, 
 and on inspection of them the observer is not surprised at the 
 use of Dog-fish skin in place of sand-paper. 
 
 Perhaps the reader may ask why the Equisetum should be 
 taken as the prototype of the file, and the skin of the Dog-fish
 
 TOOLS OF MEASUREMENT. 267 
 
 as that of sand-paper. The reason is this. The flinty points 
 of the Equisetum are set upon parallel ridges something like 
 those of a file, while the scales of the Dog-fish are without any 
 apparent order, being crowded against each other like the cutting 
 particles upon the sand-paper. That there should not be an. 
 order, and that a definite one, is out of the question. But it 
 has not yet been detected by human eyes, and therefore may be 
 practically treated as non-existent. 
 
 TOOLS OF MEASUREMENT. 
 
 IN many of the arts, more especially those which belong to 
 engineering and carpentering as a part of architecture, it is 
 absolutely necessary to make sure of a perpendicular line, 
 i.e. a line which, if continued, would reach from any point of 
 the earth's surface to its exact centre below and its zenith 
 above. "Were it not for the power of producing this line, none 
 of the great engineering works of modern or ancient days 
 could have been undertaken. 
 
 Take, for example, the wonderful tunnels which have been 
 driven through the earth, of which the Mont Cenis Tunnel is 
 one of the greatest triumphs of modern engineering. Begin- 
 ning, as the workmen did, at opposite ends of a tunnel many 
 miles in length, and 'labouring only by the lines laid down by 
 the engineers, the men worked steadily on until they met in 
 the centre. 
 
 A few blows, and the then narrow dividing wall was shattered, 
 the men shook hands through the aperture, and then, after 
 enlarging it, leaped wildly from one side to the other, having 
 successfully solved the great problem. With such marvellous 
 precision had the lines been laid, that only a few inches had to 
 be smoothed down on either side, and the sides or walls of the 
 tunnel showed no traces of the junction. 
 
 So rapid has been the progress of engineering that a 
 tunnel of a mile in length would, within the memory of man, 
 have been thought as daring a project as was the Mont Cenis 
 Tunnel, which has just been given as an example. Indeed, I 
 know of a railway tunnel, not quite a mile in length, where 
 the engineers had committed some error, so that the two halves, 
 instead of meeting exactly, overlapped each other so much
 
 268 NATURE'S TEACHINGS. 
 
 that the mistake was only discovered by the workmen, who 
 heard the strokes of their companions' picks on their sides, and 
 not in front. Consequently, a great waste of time took place, 
 and the centre of the tunnel had to be made with a double 
 curve, like the letter S, and trains are obliged to slacken speed 
 until they have passed it. 
 
 Those who have lived long enough to remember the current 
 literature of the past generation will call to mind the 
 ridicule that was cast upon the idea of a tunnel that should 
 pass under the Thames. That it would be useful if it could be 
 completed, no one ventured to doubt, but that such an idea 
 could be conceived by any one out of a lunatic asylum was 
 rather too much for the journalists of the day. However, the 
 tunnel was made, and so proved the theorists wrong on the 
 one side. And, when made, it was of very little use, which 
 proved them wrong on the other side. Now the proposal to 
 carry a submarine tunnel from England to France excites not 
 half the opposition that was elicited by the comparative child's- 
 play of a tunnel under the Thames. 
 
 The only mode of laying down the lines on which the men 
 worked is by suspending very heavy balls to very fine wires, 
 and then, by means of delicate optical instruments, ascertaining 
 whether the wires are in line with each other. 
 
 Familiar instances of the use of this principle may be seen 
 in the plumb-rule and level of the builder or carpenter. The 
 latter, with a base of ten feet in length, is often used by the 
 gardener when he wishes to lay the absolutely level lawns 
 that are required for our modern game of croquet, where the 
 hoops are scarcely wider than the balls, and the lawn has in 
 consequence to be nearly as level as a billiard table. 
 
 I may here remark that the name plumb-rule is derived from 
 the Latin word plumbum, or lead, in allusion to the leaden 
 weight at the end of the string. The word " plumber " is due 
 to the same source, and signifies a worker in lead. 
 
 THESE invaluable aids to the development of civilisation are 
 due to one principle, namely, that which we call Gravitation, 
 but which ought more properly to be termed Attraction, and 
 which attracts all parts of the earth towards its centre. "We 
 are all familiar with the anecdote of Newton and the falling
 
 GRAVITATION. 
 
 269 
 
 apple, which may be true or not, but which at all events bears 
 on the present subject. 3STo matter on what portion of the 
 spherical earth a tree may be, every fruit becoming disengaged 
 from it is attracted to the earth, the line which it takes, unless 
 disturbed by external forces (such as wind, &c.), being that 
 which passes from the zenith to the centre of the earth. 
 
 This imaginary line is a perfect perpendicular, and the 
 visible line which is formed by the delicate wire of the tunnel- 
 boring engineering instrument, or the comparatively coarse 
 string of the plumb-rule and level, are approximations suffi- 
 ciently close for practical purposes. So it is in a mathematical 
 
 i 
 
 FALLING FRUIT. 
 
 PLUMB -RULE. 
 
 proposition. As mathematical lines have no breadth, they are 
 simply indicated or represented by the lines of the figure, the 
 bodily eye being incapable of seeing what is perfectly visible 
 to the mental eye, namely, length without width. So the 
 wire and string perform in practical work exactly the same 
 office which is fulfilled by the lines of a mathematical proposi- 
 tion drawn on paper. 
 
 We have already, when treating of the Fall-trap, seen how 
 this principle is brought into operation by those who are 
 utterly incapable of discerning the physical principle, though 
 they can apply it materially with wonderful effect. 
 
 IT is, perhaps, needless to mention the value of the Measure 
 to any handicraftsman. 
 
 I well remember that when, some twenty-four years ago, I 
 was taking lessons from a carpenter in the art of making 
 ladders, gates, fences, hurdles, and other rough-and-ready work, 
 my quaint old tutor related an anecdote of and against himself.
 
 270 NATURE'S TEACHINGS. 
 
 He very ingeniously set me to work at boring the auger-holes in 
 the gate-posts which were to be united by the mortise chisel 
 and mallet, and to sweeten the rather severe, because unaccus- 
 tomed, labour, told me that, when he was a boy, he was doing 
 just the same thing. 
 
 Being rather tired of twisting the auger handle (and no 
 wonder either), he withdrew the instrument, and put his finger 
 into the hole by way of ascertaining its depth. Immediately 
 he found himself on his back, having received a tremendous 
 box on the ear from his father, whose parental wrath was 
 excited by the idea of his son condescending to use his finger 
 by way of measure, when he had a two-foot rule in its own 
 special pocket. 
 
 There are, however, many cases where even a two-foot rule 
 would be insufficient for the work, and where a measure of 
 thirty or forty feet is needed. 
 
 Now, there is no doubt that by means of a two-foot, or 
 even a six-inch, rule any number of feet might be measured 
 accurately ; but, considering the number of junctions that have 
 to be made, it is not likely that any pretence to accuracy could 
 be insured. 
 
 Then, a rod of forty, or even of twenty, feet in length would 
 be awkward and unmanageable, and the only plan left is to 
 take a string or cord of the requisite length. 
 
 Even here, however, is a difficulty. The .string would not 
 allow of short measurements, such as inches, being written 
 upon it. Let, however, a broad tape of inelastic material be 
 substituted for the string, and all is easy enough. 
 
 The next plan is to provide for the portability of the tape in 
 question, to insure its reduction into the smallest possible com- 
 pass, and to be sure that it is not twisted so as to damage its 
 accuracy. These objects are all attained by the ordinary Tape 
 Measure of the present day, which, whether it be a yard 
 measure in a lady's workbox, or a surveyor's measuring tape, 
 is a ribbon of comparatively inelastic material, coiled up when 
 not wanted, and capable of being drawn out to its fullest 
 extreme when needed. 
 
 Putting aside the breadth of the line, and consequently dis- 
 regarding the liability to twist, we have in the Fishing-reel 
 of the modern angler an exact case in point. So we have in
 
 THE SPIRIT-LEVEL. 271 
 
 the lady's yard measure, and in the gardener's or builder's 
 tape, all these being modifications of the same idea. 
 
 OVIPOSITOB OP GALL-FLY. 8PBING MEA80BE. 
 
 SUPPOSE now that we pass to Nature, so as to ascertain 
 whether any such provisions were in existence before it was 
 imitated, however unconsciously, by man. This certainly was 
 the case with one of the commonest and most insignificant of 
 our insects, the little Gall-fly, belonging to the genus Cynips. 
 It could not lay its eggs without the aid of a very long ovi- 
 positor, and, owing to structural details, it cannot carry that 
 ovipositor in a straight line, as is done by many insects, some 
 of which have already been mentioned. Accordingly, it is 
 coiled up exactly like our measuring tapes, and can be unrolled 
 when needed. The long, protrusible tongues of the Wryneck, 
 Creeper, and Woodpecker are examples of a similar structure, 
 the tendinous portions being coiled round the head when not 
 needed. 
 
 THE SPIRIT-LEVEL. 
 
 HAVING now seen how the forces of Nature enable us to 
 produce a perfectly perpendicular line, we will see how the 
 same force, though applied in a different manner, enables us to 
 produce a perfectly horizontal line, the intersection of the two 
 lines producing a right angle. 
 
 The measuring tool in question is called the Spirit-level, 
 and is represented on the right hand of the accompanying 
 illustration. Its construction is very simple, consisting of a 
 
 
 FLOATING BUBBLE. 8PIEIT-LKVBL. 
 
 tube, nearly filled with spirit, and having just one bubble of 
 air in it. Now, owing to the force of gravitation, the air- 
 bubble must always be uppermost. Consequently, if the tube 
 be a perfect cylinder, whenever it is held so that the bubble is
 
 272 NATURE'S TEACHINGS. 
 
 in the centre, the tube must be horizontal, a hair's breadth of 
 deviation altering the line. I may here mention that, as far as 
 the principle of the instrument goes, water would serve the 
 purpose as effectively as spirit. But as in cold weather the 
 water might freeze, and so burst the tube, as well as being 
 useless until it was thawed, spirit is always substituted. 
 
 This instrument is used for various purposes. Sometimes it 
 is employed for levelling billiard tables, or for ascertaining the 
 exact level of walls and other parts of buildings. Surveyors 
 could scarcely -do their work without the Spirit-level, which 
 forms an important part of their chief instrument, the 
 theodolite. Indeed, the new science of land drainage, by which 
 the tough, unproductive clay soil is converted into fertile earth, 
 is entirely dependent on the use of the Spirit-level, which 
 detects the slightest rise or fall in the ground. 
 
 A most ingenious modification of the Spirit-level is used by 
 military engineers, and is known by the name of the " Con- 
 touring-glass," a term which requires some explanation. 
 
 It is of the utmost importance that a military engineer 
 should be able, whether on foot or on horseback, to ascertain 
 the approximate heights of the various points which he visits, 
 the efficiency or failure of a battery very much depending on 
 the comparative elevation of the spot on which the battery is 
 placed, and that of the place against which its fire is directed. 
 In an unknown country, of which no detailed maps exist, an 
 invading force must of necessity depend on the extemporised 
 surveys of their engineer officers, and one of the most valuable 
 of their devices is the system of Contouring, invented, as far as 
 I know, by the late Colonel Hutchinson, R.E. 
 
 The idea is simple enough. A hill is seen, and the engineer 
 makes a sketch of it before he ascends. At the foot he halts, 
 and marks the spot where his foot presses the earth. He then 
 looks in front at a spot exactly on the level of his eye, marks 
 it, and walks to it. He then draws a line across his sketch, at 
 the exact spot on which he is standing, and that is the first 
 "contouring line." Others follow, until he has reached the top 
 of the hill. 
 
 Now, if he can trust himself to look exactly horizontally, he 
 has ascertained the elevation of every part of the hill. He 
 knows the height of his eye from the sole of his foot, and
 
 THE CONTOURING-GLASS. 273 
 
 jalculates accordingly. Suppose, for example, that it be five 
 feet, and that ten contouring lines are marked, he knows that 
 the entire height is fifty feet, and that each line means an eleva- 
 tion of five feet. 
 
 This is a very excellent theory, but one which is not reduced 
 to practice so easily as it looks. There is nothing more decep- 
 tive than a contour, especially upon an irregular hill, the 
 invariable mistakes being either greatly to overrate or under- 
 rate the height of the contour, When I took my first lesson 
 in this art I caused much amusement to the professor under 
 whom I was studying, by making Shooter's Hill consist of 
 about seventeen contours. However, as many military students 
 made very much the same mistake, I was not so humiliated as 
 I supposed. 
 
 Of course, if a surveying officer be mounted, he takes the 
 contour line as measured from his eye to the ground through 
 the centre of the saddle. 
 
 After some practice the eye becomes so much accustomed to 
 the contouring lines that they are taken almost mechanically ; 
 but, until this result be gained, an absolute proof is needed, 
 which is furnished by the Contouring-glass which, by the 
 way, is not a glass at all, after the common acceptation of the 
 word. 
 
 It is a simple brass tube about three inches long, not thicker 
 than a man's little finger, and open throughout. A small 
 spirit-level is fixed on its lower surface, and on the very centre 
 of the upper surface is a tiny steel mirror, which projects 
 downwards like a knife-blade. In order to get a "contour," the 
 observer looks through the tube, slightly depressing its end. 
 He then gradually raises it, still looking through it. As the 
 tube becomes exactly horizontal the bubble in the spirit-level is 
 reflected in the little mirror, and the object on which the tube 
 is directed is in consequence on a level with the observer's eye. 
 
 At first the management of the contouring-glass is rather 
 tedious ; but after a little practice it can be used without 
 pausing for a single step. 
 
 INVALUABLE as is the Spirit-level, with its various modifica- 
 tions, it is nothing but an adaptation of that natural law which 
 causes the bubbles to float on the surface of a stream instead of 
 
 T
 
 274 NATURE'S TEACHINGS. 
 
 being submerged below it. We have all seen the multitudinous 
 bubbles of soda-water, or of any effervescing liquid, and have 
 noticed how they are very small when generated, but enlarge 
 quickly, and rise to the surface with a rapidity equal to their 
 enlargement. The same phenomena may be observed in any 
 water-fall, or even in the very familiar and unpoetical opera- 
 tion of pouring beer from a jug into a glass. 
 
 The reader will see that in the plumb-rule, the level, and 
 the spirit-level one single principle is employed, namely, the 
 attraction of matter towards the centre of the earth. In the two 
 former instruments this attraction gives a vertical line, and in 
 the latter it gives a horizontal line, but the principle is the 
 same in both. . 
 
 CALLIPERS. 
 
 WE conclude the history of measuring tools with the Callipers. 
 For ordinary purposes, and upon a plane surface, the Com- 
 passes answer every purpose. But there are various arts, espe- 
 
 JAWS OF 8IAU3. 
 
 cially sculpture, in which the compasses, with their straight 
 legs, are absolutely valueless, and their place must be supplied 
 by a differently shaped instrument. For example, no ordinary 
 compasses could measure the exact distance from the nostril to 
 the back of the head, or even touch two points at opposite sides 
 of a limb, and it is therefore necessary to have compasses with
 
 CALLIPERS. 275 
 
 curved legs. These are termed Callipers, and can be used on 
 a plane as well as on a rounded surface. 
 
 NATURAL Callipers are plentiful enough, and may be 
 found extensively among the insect tribes. There are, for 
 example, the pincers of the Earwig, which have already been 
 described on page 259, and which are, in the common species, 
 formed exactly like the Callipers of the sculptor. 
 
 Then we have various insect jaws, especially those of the 
 carnivorous species, one of the most curious being the large 
 insect which is shown in the illustration, upon a very reduced 
 scale. In the male the jaws are exceedingly long and curved, 
 as may be seen by reference to the illustration. I have now 
 before me a pair of sculptor's callipers, and the resemblance 
 between them and the jaws of the Sialis is strangely close, the 
 curve being almost exactly the same in both cases. 
 
 The scientific name of this insect is Sialis armata, and it 
 is a native of Columbia. 
 
 T2
 
 OPTICS. 
 
 CHAPTER I. 
 
 THE MISSIONS OF HISTOKY. THE CAMERA OBSCURA. LONG 
 AND SHORT SIGHT. STEREOSCOPE AND PSEUDOSCOPE. 
 MULTIPLYING-GLASSES. 
 
 The Camera Obscura. Telescopes, Microscopes, and Spectroscopes, and their 
 separate Objects. Structure of the Camera Obscura. The Double Convex 
 Lens. Its Use as a Burning-glass. The Meridian Gun in Paris. Significa- 
 tion of the Word " Focus." The Human Eye and its Analogies to the Camera 
 Obscura. Forms of various Lenses. Long and Short Sight. Their Causes 
 and Means of Remedy. Alteration of Sight in the Diver. Long and Short 
 sighted Spectacles. The Eye of Birds. Its beautiful Structure. Washing- 
 glasses and the "Nictitating" Membrane. Combination of Images. 
 Natural Stereoscopes. The Pseudoscope and its Effects on an Object. The 
 Multiplying-glass. The Eight Eyes of the Spider and their Arrangement. 
 The Seventy Thousand Eyes of the Butterfly. Form of the Facets. 
 
 HISTORY seems to fall into natural divisions, and to write the 
 records of time in successive epochs, recording the advance 
 of the human race. Some of them have apparently disappeared 
 except by the strange relics which they have left behind, but 
 though nothing is known of the men who worked in these 
 ancient times, they stamped their mark upon the earth, and 
 evidently left the world better than they found it. 
 
 A very admirable treatise on this subject has been written by 
 the late Rev. J. Smith, called the " Divine Drama of Creation." 
 In this work he divides the progress of the human race into 
 five acts, like those of a drama. The first act is the Hebrew 
 Mission, the second the Greek Mission, the third the Roman 
 Mission and the Middle Ages, the fourth the National Mission, 
 and the fifth the Universal Mission. 
 
 Certainly a scene of the last act is now in progress, and may 
 be entitled the Scientific Mission. The last hundred years 
 nave been indeed the age of discovery, and, during that time,
 
 THE CAMERA OBSCURA. 277 
 
 the life of civilised man has been quite altered, so that practi- 
 cally his sojourn upon earth has been doubled. Steam, with 
 all its various applications, electricity, and other kindred arts 
 have become so intermingled with our lives, that it is difficult 
 to imagine what our state would be if we were suddenly and 
 utterly deprived of them. The loss to all would be incal- 
 culable, and not the least of the losses would be that of ready 
 communion with our fellow-creatures. 
 
 Of these arts we will now take that which is named at the 
 head of this division of the book, and see how far it is a 
 development of natural facts. 
 
 THE CAMERA OBSCURA AND THE EYE. 
 
 I HAVE already spoken of arts as being akin to each other. 
 They are more than this, and every day of the world's pro- 
 gress teaches us that Art, Science, and Manufacture are sisters, 
 all born of one family, and all depending mutually on each 
 other. 
 
 Take, for example, our present theme- 1 namely, Optics 
 and see how dependent it is upon Manufacture and Art. 
 "Without the former, man could not construct those beautiful 
 telescopes, microscopes, spectroscopes, of the present day, which 
 are evidently but the precursors of instruments which will work 
 still greater marvels. 
 
 The first enables us to see solar systems without number, to 
 which our own, vast as it seems to us, is but as a grain of sand 
 in the desert. The next instrument makes revelations as mar- 
 vellous of the infinitely minute as does the telescope of the 
 infinitely great, enabling us to see living organizations so small 
 that thirty-two millions could swim in a cubic inch of water 
 The third, a comparatively modern instrument, reveals the 
 composition of objects, and can detect and register the 
 materials of which the sun and fixed stars are made, or 
 detect an adulteration in wine. It can adapt itself equally to 
 the telescope and microscope, and the very same instrument 
 which will reveal the character of an invisible gas in the Pole- 
 star, when attached to the telescope, can, when connected with 
 the microscope, point out the presence of half a corpuscle of 
 blood where no other instrument could discover any trace of it.
 
 278 NATURE'S TEACHINGS. 
 
 All these instruments, together with many others, will be 
 described in the present division of the work, and their 
 analogies with Nature shown. 
 
 WE will now take the subject of the Camera Obscura, an 
 instrument with which the photographic apparatus of the 
 present day has made most of us familiar. As its action 
 depends chiefly upcn the glass, or lens, through which the 
 rays of light pass into the instrument, we will first explain 
 that. 
 
 A " lens " is a glass formed in such a manner that the rays 
 of light which pass through it either converge to a focus, or are 
 dispersed, by means of the law of refraction. Every one who 
 has been photographed and who has not ? will remember 
 that when the sitter has taken his position, the photographer 
 brings to bear upon him a circular glass fixed into a short 
 tube, and then looks through the instrument as if he were 
 taking aim with some species of firearm. It is no matter of 
 wonder that when savages see the photographic camera for the 
 first time they are- horribly frightened, for there is really 
 something weird-like in the appearance of the lens thus pre- 
 sented. 
 
 Now, this lens is of the shape called " double convex," both 
 sides being equally rounded, so that a section of it would be 
 shaped very much like a parenthesis (). The effect of this 
 form of lens is to bring the rays of light ,to a point at a given 
 distance from the centre. This point is called the " focus," 
 and is well known by means of the common burning-glass, 
 which will set fire to objects placed in its focus, while itself 
 remains quite cool. 
 
 I have seen lead pour down like water when placed in the 
 focus of a large burning-glass, and even the harder metals will 
 yield to the power of the sun's rays when thus concentrated. 
 
 There is nothing which gives a more vivid idea of the 
 amount of heat thrown on the earth by the rays of the sun 
 than the effects of a moderately large burning-glass say one 
 of six inches in diameter. If we trace a circle of this size on 
 the surface- of the earth, it does not seem as if any very great 
 amount of heat can be received, but when we catch the rays of 
 that circle in our glass, and bring them together upon the
 
 THE DOUBLE CONVEX LENS. 279 
 
 focus, the amount of heat can be appreciated. The well-known 
 meridian gun in the Palais Royal is fired by the sun. A burn- 
 ing-glass of no very great size is placed over the touch -hole of 
 the gun, with which its focus coincides. The lens is turned 
 in such a manner that, as the sun attains the meridian, its 
 rays are thrown upon the touch-hole, and consequently fire 
 the gun. 
 
 The word focus is the Latin term for a domestic hearth, and 
 is used in allusion to the heat which is manifested at the 
 point on which the rays of the sun converge. 
 
 It is evident that, after reaching the focus, the rays, if they 
 be not intercepted by some object, will cross each other, and 
 form a large image, but reversed. This part of the subject 
 will presently be explained. 
 
 THE accompanying illustration shows two figures, one repre- 
 senting the section of a double convex lens made by the hands 
 of man, and the other that of a double convex lens as seen in 
 Nature. 
 
 CRYSTALLINE LENS OF HUMAN EYE. DOUBLE CONVEX LEVS. 
 
 The former has already been explained. The latter is the 
 double convex lens of the human eye, by means of which the 
 images of external objects are conveyed to the brain. When- 
 ever this lens becomes thickened by disease, the sight is 
 gradually dimmed, and at last total blindness is the result. 
 This disease is popularly called " cataract," and until late days 
 was incurable. Now, however, any good oculist will attack a 
 cataract, and either partially or entirely restore the sight. This 
 operation is performed by carefully removing the convex lens, 
 and supplying its place with a glass lens, which throws the 
 rays of light on the same focus.
 
 280 
 
 NATURE'S TEACHINGS. 
 
 The figure shows the double convex lens of the human eye 
 in its place. 
 
 HAVING now seen something of the properties of the double 
 convex lens, we will examine its application to the Camera 
 Obscura. 
 
 The lens is placed on one side of the camera, and is so made 
 that it can be slid backwards and forwards, and the focus 
 altered at will. The camera itself is a box completely closed, 
 so that no light can enter it except that which passes 
 through the lens. The latter is so arranged that the rays 
 which pass through it are crossed, and throw their image on 
 
 BYE AND IMAGE. 
 
 CAMERA OBSCURA AND IMAGE. 
 
 the opposite side of the camera. In the photographic camera 
 a piece of ground glass is placed at the end, so that the rays 
 fall upon it, and the operator can see whether the image is a 
 good one. Of course the figures are reversed, so that the sitter 
 seems to be on his head, but that is a matter of no conse- 
 quence. Exactly the same effect is produced by the marine 
 telescope. 
 
 The general structure of the camera is shown in the illustra- 
 tion, all needless details being omitted. 
 
 I may here remark that the term " camera obscura," or 
 dark chamber, alludes to the fact that the box .is com- 
 pletely closed, and, but for the rays which pass through the 
 lens, would be absolutely dark. 
 
 THE opposite illustration shows the most perfect camera 
 obscura that can be imagined, namely, the human eye. Here 
 we have a dark chamber, a double convex lens, and an image 
 falling upon the back. Here the optic nerve comes into play, 
 takes cognisance of the image, and conveys the idea to the
 
 STRUCTURE OF THE EYE. 281 
 
 brain. With a little trouble, a real eye, say that of an ox, 
 can be dissected out, and employed as a camera obscura, the 
 operator seeing in the back of the eye, or " retina," the same 
 image which the ox would have seen if it had been alive. 
 
 In photography, the operator, when he has found that 
 a perfect image is thrown upon the ground glass, which 
 represents the retina of the eye, substitutes for it a sensi- 
 tive surface, on which the rays are projected, and which, 
 by chemical means, produce a permanent instead of a fleeting 
 object. 
 
 EXAMPLES of other lenses may be found in Nature. She, 
 moreover, can perform a task which man has never even 
 attempted, namely, the change of form in a lens according to 
 the duty which it has to do. How this wonderful object is 
 attained we shall presently see. 
 
 There is a form of lens extremely useful in Optics, namely, 
 the " Plano-convex" lens. This is, in fact, one half of a double 
 
 HUMAN EYE : SECTION OP COBNEA, &C. PLANO-CONVEX LENS. 
 
 convex lens, the section being made through its edges, and the 
 plane sides polished as well as the convex. As, however, this 
 is only a half of the double convex lens, it does not need 
 further explanation. Its natural counterpart may be seen in 
 the annexed illustration. 
 
 A somewhat more complicated form of lens is called the 
 " Meniscus," one side of which is convex and the other concave. 
 A good example of the meniscus may be found in the old- 
 fashioned watch-glass, before watchmakers took to flattening 
 them, and watch-wearers were not ashamed to carry a " turnip," 
 in which there was room to spare for the works. If a section 
 of such a glass were taken, it would assume the form of a half-
 
 282 
 
 NATURE S TEACHINGS. 
 
 moon. This, in fact, is the meaning of the term " meniscus," 
 which is a Greek word, signifying a little moon. If the same 
 glass were solid, or even filled with water, it would form a 
 "plano-convex" lens. 
 
 Of course the outer curve of the meniscus must be larger 
 than the inner curve, but in some cases the disproportion is 
 very strongly marked, the outer curve being very large, and 
 the inner curve very small. An example of such a meniscus 
 may be seen in the human eye. If the reader will refer to the 
 illustration on page 280, in which the structure of the eye is 
 shown, he will see the meniscus lens in combination with the 
 double convex. The former has already been explained, and 
 the latter is formed by the vitreous humour which fills nearly 
 the entire globe of the eye. Its larger curve is due to the form 
 of the eyeball, and the smaller to the convex lens. 
 
 LONG AND SHORT SIGHT. 
 
 IT has already been mentioned that the focus of a convex 
 lens is shorter in proportion to its convexity, and that in conse- 
 quence its magnifying power is increased. For example, the 
 large glasses through which pictures are viewed are compara- 
 tively thin in proportion to their diameter, while the lenses 
 
 FRAME OP OWL'S EYE : LENS 
 OP DITTO. 
 
 SHORT AXD LOJTO SIGHTED EfES 
 (WITH SPECTACLES). 
 
 employed for the highest powers of the microscope are scarcely 
 larger than small shot, and nearly as globular. It naturally 
 follows that any instrument to which a lens is adapted, whether 
 it be microscope or telescope, must depend for its focus on the 
 greater or less convexity of the lens in question. 
 
 Again taking as our example the human eye, we find that 
 there are very few persons who from youth to age possess or
 
 LONG AND SHORT SIGHT. 283 
 
 preserve eyes which can read small type at a moderate distance, 
 and can clearly define the outlines of distant objects. Nearly all 
 people, even if in their youth they possess good sight, lose it as 
 they grow older. They can discern distant objects well enough, 
 but, when they come to reading, they are obliged to hold the 
 book at arm's length before they can distinguish the letters. 
 
 This defect is caused by the insufficient convexity of the lens, 
 so that the focus is thrown too far back, and it is corrected by 
 wearing spectacles sufficiently convex to supply the deficiency 
 in the lens of the eye. 
 
 An admirable example of temporary long-sightedness is 
 familiar to every diver, though he may be unconscious of its 
 cause. Suppose that into very clear water of some twelve feet 
 in depth, a white object, say a common jam-pot, is thrown, it 
 can be clearly discerned from the shore, unaltered in shape or 
 size. But, when the diver searches for it, he sees at first only 
 something white, large, undefined, and wavering, and only finds 
 it resume its proportions as he approaches it. This phenomenon 
 is due to the pressure of the water upon the eyeball, which 
 flattens it, and so throws the focus too far back for a clear 
 image. Nowadays this defect is remedied by the use of very 
 convex spectacles, so convex, indeed, that, if worn in the air, 
 they would render the wearer incapable of seeing anything at 
 more than an inch or so away from him. But, when worn in 
 the water, they only supply the deficiency of the compressed 
 eyeball, and so restore the focus to its proper position. 
 
 THOSE who suffer from short-sightedness can see with great 
 distinctness objects which are close at hand, but those at a 
 little distance seem to have no particular outline, and appear as 
 if they were viewed through a fog, thus causing a constant and 
 almost painful strain on the eyes. The cause of this defect is 
 the too great convexity of the lens, which therefore throws its 
 focus short of the required spot. The means of remedy are 
 exactly opposite to those which are used for long-sighted 
 persons, a concave lens being placed in front of the eye, so as 
 to throw the focus farther back, and relieve the organ from 
 the strain. 
 
 Although we have not yet invented a machine that can alter 
 the focus at will, we may take a hint from Nature. We have
 
 284 NATURE'S TEACHINGS. 
 
 already seen how the pressure of water upon the front of the 
 eye lessens its convexity, and makes it long-sighted. Conse- 
 quently, if we could apply pressure round it, we could make it 
 more convex, and so neutralise the weight of the water. 
 
 There is a wonderful piece of machinery in Nature which 
 really does perform this office, the eye, at the will of its owner, 
 becoming either telescopic or microscopic. This quality is very 
 desirable in birds, especially those which are predacious and of 
 rapid flight, as they might either fail to see their prey at a 
 distance, or might dash themselves against some obstacle when 
 they were close upon it. 
 
 The eye of the Owl affords a beautiful example of machinery 
 which produces this effect, and the means which are used may 
 be understood by inspecting the accompanying illustration. 
 
 It will be seen that the eyeball is set in a framework composed 
 of thin bony plates, just like a glass in a telescope. When these 
 plates are relaxed, the whole eyeball is flattened, so as to enable 
 the bird to see an object at a very great distance. But, when they 
 are contracted, they render the whole eye globular in propor- 
 tion to their pressure, and enable the bird to see objects which 
 are very close to it. In fact, the eye becomes a telescope or 
 microscope as needed. 
 
 Many reptiles possess this arrangement of bones, but the 
 birds have even a more delicate mode of obtaining the focus of 
 the eye. This is by means of a curious organ called, from its 
 shape, the " pecten," or comb, which is placed in the vitreous 
 humour at the back of the eye, and connected with *the optic 
 nerve. It is a congeries of arteries and veins, so that it can be 
 rapidly enlarged by forcing blood into it, or diminished by 
 allowing the blood to withdraw. 
 
 As the liquid in which it rests is practically incompressible, 
 it follows that when the comb expands, it causes the chamber 
 of the vitreous fluid to expand, and so forces the lens forward. 
 When, however, the blood retires from the comb, the lens 
 returns to its original place. This, as the reader may have 
 noticed, is the same principle as that which is followed in alter- 
 ing the focus of a telescope in order to suit the sight of different 
 individuals. Perhaps a still better illustration may be found in 
 the coarse and fine adjustment of the microscope, the former of 
 which moves the whole tube, and may be compared to the bony
 
 THE STEREOSCOPE. 285 
 
 ring ; while the latter causes one part to slide over the other, 
 and is analogous to the comb. 
 
 The movements of this organ are believed to be as involuntary 
 as the dilatation and contraction of the iris ; but, whatever 
 may be the case, it is one of the most beautiful examples of 
 natural mechanics, and far surpasses the most delicate machine 
 that can be made by man. 
 
 In the illustration of the microscope, which is to be found 
 on page 286, both these movements are given, the double 
 vertical wheel being the coarse movement, and the fine move- 
 ment being supplied by the single vertical wheel just above 
 them. 
 
 WHILE we are on this subject, we may see how Art uninten 
 tionally copies Nature, even in trivial details. Every one who 
 is in the habit of using optical instruments, more especially 
 those who are forced to wear spectacles, are aware of the neces- 
 sity of keeping the glasses as clean as possible, and, where the 
 instruments are delicate, always have by them a piece of clean 
 wash-leather for the express purpose of wiping the glasses. 
 
 Here, again, Nature has anticipated Art. In our own case, 
 we have in the human eye a good example of such natural 
 mechanism, the eyelids being formed quite as much for the 
 purpose of washing the surface of the eyeball as of excluding 
 light. 
 
 Many animals are provided with a special apparatus for the 
 purpose, called the "nictitating membrane." It is, in fact, a 
 sort of inner or supplementary eyelid, which can be drawn over 
 the eye while the external lids remain comparatively unmoved. 
 It is very conspicuous in the owls, and gives to those birds 
 that almost comical look of perpetual blinking with which we 
 are so familiar. 
 
 THE STEREOSCOPE AND PSEUDOSCOPE. 
 
 MANY persons have wondered how it happens that, as we 
 have two eyes, we do not see two images instead of one. 
 Practically, this is always the case, for the eyes, especially when 
 they look on solid bodies, see two different images, because they 
 contemplate the object from different points of sight.
 
 286 NATURE'S TEACHINGS. 
 
 This may be easily ascertained by looking at a given object 
 first with one eye, and then with, the other, when it will be seen 
 that the image presented to the right eye is slightly different 
 from that of the left eye, but that the two can be combined into 
 one by a very slight inward movement of both eyes, and thus 
 the effect of a solid body be produced. Sometimes, when people 
 are weak, and cannot control the united movement of the eyes, 
 not only two, but five or six images are at once presented to 
 the mind, and produce a strange sense of bewilderment and 
 confusion. 
 
 COMBINATION OP HUMAN EYES. STEREOSCOPE. BINOCULAR MICROSCOPE. 
 
 Painters are obliged to avail themselves of this peculiarity, 
 and to make allowances for the double vision. If they do not, 
 the effect of the painting is flat, and it appears as if the artist 
 had only used one eye. 
 
 A good proof of this fact may be seen in Stereoscopic photo- 
 graphs, especially of scenery. If each be viewed separately, 
 it often appears quite unintelligible, but, when they are com- 
 bined by the instrument, they seem to spring into life as it 
 were, and appear solid enough to be grasped. 
 
 Now, the Stereoscope is avowedly constructed on the same 
 principle as the double vision of the eye, so that when it applies 
 itself to two photographs of the same object which have been 
 taken from different points of view, it combines them, and 
 gives them as solid an appearance as if they were realities.
 
 THE I'SEUDOSCOPE. 287 
 
 So wonderfully close is the representation, that the idea of a 
 place obtained by means of the combination of the photograph 
 and Stereoscope is quite as vivid and correct as if it had been 
 gained by actual observation. 
 
 The principle of the Stereoscope is now applied to the best 
 microscopes, and its value is incalculable, especially when low 
 powers are used, i.e. those of not less than half an inch focus. 
 The real beauty of many objects could never have been appre- 
 ciated but for this discovery, nor their true form denned. 
 
 On the left hand of the illustration is shown the combining 
 power of the eyes. Supposing the right eye only to be brought 
 to bear upon the little cylinder, only one side of it will be 
 seen, and it looks nearly flat. The same is the case with the 
 left eye. But, when both eyes are used together, both sides of 
 the cylinder are presented to the mind, and thus we get the 
 effect of solidity. 
 
 The Stereoscope is so formed, by means of lenses, that the 
 two figures become combined into one, the rays of light being 
 turned out of their course by the arrangement of the glasses. 
 
 The Stereoscope, however, although a useful assistant to the 
 vision, is not necessary. It is perfectly possible to combine the 
 two figures without any stereoscope, and to do so merely by 
 squinting, if we may so call it, at the figures. The power of 
 combination is gained with a very little practice, and in a 
 short time the observer will be capable of producing stereo- 
 scopic effects without needing a Stereoscope. This ability is 
 very useful when inspecting photographs in a shop-window. 
 Of course the figures are not so much enlarged as they are 
 with the stereoscope, but they are nevertheless quite as clear 
 and well defined. 
 
 THERE is an instrument called the Pseudoscope, which, as its 
 name imports, gives a false idea as to the nature of the object 
 which is viewed through it, converting hollow objects into 
 solid, and vice versa. The following description of its effect is 
 given by Wheatstone : 
 
 " When an observer looks with the pseudoscope at the interior 
 of a cup or basin, he not unfrequently sees it at first in its real 
 t~rm ; but by prolonging his gaze he will perceive the conver- 
 sion within a few minutes ; and it is curious that, while this
 
 288 NATURE'S TEACHINGS. 
 
 seems to take place quite suddenly with some individuals, as if 
 the basin were flexible, and were suddenly turned inside out, it 
 occurs more gradually with others, the concavity slowly giving 
 way to flatness, and the flatness progressively rising into con- 
 vexity. 
 
 " Not unfrequently, after the conversion has taken place, the 
 natural aspect of the object continues to intrude itself, some- 
 times suddenly, sometimes gradually, and for a longer or shorter 
 interval, when the converse will again succeed it as if the 
 new visual impression could not at once counteract the previous 
 results of recent experience. At last, however, the mind seems 
 to accept the conversion without further hesitation ; and after 
 this process has once been completely gone through, the observer, 
 on recurring to the same object, will not find it possible to see 
 it in any other than its converted form, unless the interval 
 should be long enough to have allowed him to forget its aspect. 
 
 " Vagaries, however, sometimes occur in these experiments of 
 which it is difficult to give any certain explanation, but which 
 would be probably found referable to the same general principle, 
 if we were acquainted with all the conditions of its operation." 
 
 THE MULTIPLYING-GLASS. 
 
 STILL more extraordinary examples of the combining power 
 of vision are to be found in the eyes of spiders and insects, 
 more especially when we compare them with the work of man. 
 
 BYES OP SPTDEB. MULTIPLYING- GLASS. 
 
 If we take a common Multiplying-glass, such as is shown in 
 the figure, and look at a flower or other object through it, we 
 see the object repeated as many times as there are different 
 foci of vision in the instrument.
 
 EYES OF THE SPIDER. 
 
 Now, taking for example the eyes of a Spider, it would be 
 natural to suppose that the same result would occur, especially 
 as the foci of the eyes point in different directions. The left- 
 hand figure in the illustration represents the eight eyes of one 
 of our common Spiders, belonging to the genus Clubiona, which 
 may be found in almost any outhouse, sitting in its curious web, 
 and ready in a moment to run for safety into its silken tunnel. 
 
 It will be seen that the foci of all the eyes are in different 
 directions, and so placed as to command a large radius. Ob- 
 servers have remarked that the eyes are placed in Spiders so as 
 to suit their habits. " Those spiders," writes Professor Owen, 
 in his " Comparative Anatomy," " which hide in tubes, or lurk 
 in obscure retreats, either underground or in the holes or fissures 
 of walls or rocks, from which they emerge only to seize a passing 
 prey, have their eyes aggregated in a close group in the middle 
 of the forehead, as in the Bird-spider, the Clotho, &c. 
 
 "The spiders which inhabit short tubes, terminated by a 
 large web, exposed to the open air, have the eyes separated and 
 more spread upon the front of the cephalothorax. 
 
 " Those spiders which rest in the centre of a free web, along 
 which they frequently traverse, have the eyes supported on 
 slight prominences, which permit a greater divergence of their 
 axis ; this structure is well remarked in the genus Thomisa, the 
 species of which live in ambuscade in flowers. 
 
 "Lastly, the spiders called Errantes, or "Wanderers, have 
 their eyes still more scattered, the lateral ones being placed at 
 the margin of the cephalothorax." 
 
 Yet, although each eye produces a separate image, it is clear 
 that upon the mind of the Spider only a single idea can be 
 impressed, for that otherwise all would be confusion. There 
 must, therefore, be some mechanism in the structure of the eye, 
 the nature of which we are not as yet able to understand. 
 
 A STILL more remarkable instance of a natural Multiplying- 
 glass may be found in the eyes of many insects. 
 
 The form of multiplying-glass shown in the accompanying illus- 
 tration is probably familiar to most of my readers. It consists of 
 a convex piece of glass, cut into a number of facets, and showing 
 in each facet a distinct and separate image of the object to 
 which it is directed. Now, the compound eyes of insects are 
 
 u
 
 290 
 
 .NATURE S TEACHINGS. 
 
 constructed on much the same principle, except that the number 
 of facets is infinitely more. Taking, for example, the eyes of 
 the Tortoise-shell Butterfly, we find that there are about seventy 
 thousand lenses or facets. Now, it is possible, with care, to 
 remove the eye from the insect, cleanse it, and arrange it in 
 a microscope in such a way that objects can be seen through 
 it. When this is done, a separate image is seen in each facet, 
 just as is the case with the Multipying-glass, only, as the 
 facets are very much more numerous, the effect is proportion- 
 ately more striking. 
 
 The reader may notice that the facets of the insect eye 
 appear to be hexagons as perfect as those of the honey- 
 
 IKSKCT EYE. 
 
 MULTrPLYIXO-GL ASS . 
 
 comb. This appearance is probably due to the fact that each 
 eye is covered with a convex plate of glassy brightness and 
 transparency, and that, when such objects are viewed from the 
 front, they appear to have hexagonal instead of rounded out- 
 lines. A familiar example of this fact may be found in the 
 glass tumblers which are ornamented with rounded projections 
 on their surface. If a photograph of one of these tumblers 
 be taken, the resemblance to the hexagonal markings of th.e 
 insect eye is so close that the tumbler might easily be taken for 
 the eye.
 
 OPTICS. 
 
 CHAPTER H. 
 
 THE WATER TELESCOPE. IRIS OF THE EYE. MAGIC LANTERN. 
 THE SPECTROSCOPE.- THE THAUMATROPE. 
 
 Limits to Sight in the Water. Effect of a Ripple. The Eyes under Water. The 
 Water Telescope, its Structure and Mode of Use. Gyrinus, or Whirlwig- 
 beetle, and its Douhle Set of Eyes. The Iris of the Eye, and its Double Set of 
 Contractile Fibres. Cotterill's Lock and its Structure. The Magic Lantern 
 and its Principle. Chinese Shadows. Spectre of the Brocken. An Adven- 
 ture in Wiltshire. Effect of the Halo. The Spectroscope. Its Structure 
 explained. A Star on fire. Motes in the Sunbeams. Bessemer Steel made 
 by aid of the Spectroscope. Absorption Bands. Detection of Blood. A 
 Man's Life saved by the Spectroscope. The Pocket Spectroscope. The 
 Rainbow, Dewdrop, Soap-bubble, Opal, and Pearl. The Thuumatrope. 
 Structure of the Retina. Complementary Colours. The Zoetrope and 
 Chromatrope. Wheel Animalcules and their Structure. An Optical Delu- 
 sion. 
 
 THE WATER TELESCOPE. 
 
 TJWERY one who has watched the movements of the various 
 -L^ creatures which live below the surface of the water is 
 aware how entirely dependent he is on the unruffled character 
 of that surface. No matter how clear the water may be, the 
 least ruffling of the surface will effectually shut out all sight : 
 
 " But if a stone the gentle sea divide, 
 Swift rippling circles rush on every side, 
 And glimmering fragments of a broken sun, 
 Banks, trees, and skies in thick disorder run." 
 
 And there is an end of the observations. If, however, the eyes 
 can penetrate below the surface, the ruffling is of little con- 
 sequence, so long as the water is clear. Consequently, when- 
 ever the top of the b<mk is sufficiently near the water, it is 
 possible to continue the observations by lying down, and 
 immersing the head above the eyes. This plan, however, is 
 
 u 2
 
 292 NATURE'S TEACHINGS. 
 
 not a very comfortable one, although I have often followed it 
 on a windy day when the surface was too ruffled to permit of 
 vision in any other way. 
 
 Still, there is an instrument by which it is possible to counter- 
 act the ruffle of the surface, and to see objects with tolerable 
 plainness. This is called the Water Telescope, and it is of very 
 simple construction. Like the ordinary telescope, it consists of 
 a tube, but, instead of the convex and concave lenses of that 
 instrument, it has only a single glass at one end, and that 
 glass is perfectly plane. 
 
 When used, the eye is applied to the open end, and the glazed 
 end lowered into the water. The sight is then undisturbed by 
 
 WHIRLWIG-BEETLE. WATER TELESCOPE. 
 
 the ripple, and the effect is the same as if the eyes themselves 
 were lowered beneath the surface. 
 
 It is much used in looking for shells, sea-urchins, and other 
 creatures which live in the bed of the sea. 
 
 IN the insect world we have an example of a natural Water 
 Telescope. I do not say that the inventor of the Water 
 Telescope took his idea from the insect, but the reader will see 
 that he might very well have done so. 
 
 There are sundry little beetles popularly called Whirlwigs or 
 Whirligigs, and scientifically known by the name of Gyrinus. 
 All these names allude to the insect's habit of whirling about on 
 the surface of the water, with a movement which seems cease- 
 less and untiring. Allusion has already been made to the 
 Whirlwigs on page 22.
 
 IRIS OF THE EYE. 293 
 
 Their object in their perpetual waltz is not so much amuse- 
 ment as food, which chiefly consists of the tiny insects which 
 fall into the water. Now, in order to enable it to see both 
 above and below the water, a peculiar structure is required. 
 Generally the insects possess one pair of compound eyes, each 
 group being set on the sides of the head. In the Gyrinus, 
 however, there are two sets of these eyes, one pair being on the 
 upper surface of the head, and the other on the lower surface. 
 Thus, while it can use the upper pair for seeing objects which 
 are out of the water, the lower pair of eyes, which are sub- 
 merged, act the part of the Water Telescope, and enable it to 
 see objects that are below the surface. Were it not for this 
 precaution, even the ripples which it makes by its own rapid 
 progress would prevent it from seeing. 
 
 THE IRIS OF THE EYE. 
 
 I HAVE often wondered, when contemplating the astonishing 
 mechanism by which the Iris of the Eye is able to contract or 
 enlarge the pupil according to the amount of light, whether any 
 
 IBIS OP HUMAN KTB. COTTEBILL'S LOCK. 
 
 similar mechanism would be used in Art. As anatomists 
 know, the Iris is composed of two layers. One consists of 
 radiating fibres, which serve to enlarge the pupil, while 
 the other layer surrounds the latter, and by its elasticity 
 serves to contract it. As any one may see by looking in 
 a mirror and shifting the light, the pupil is perpetually 
 changing its diameter, but always retaining its circular 
 shape. A glance at the illustration will show the two layers, 
 and aid the reader in understanding the mode in which they 
 work.
 
 294 NATURE'S TEACHINGS. 
 
 Some years ago, while looking at the account given by 
 Mr. J. Price of a lock invented by Mr. Cotterill, I saw at once 
 that the inventor, whether consciously or not, had followed the 
 mechanism of the eye, as far as metal could be expected to 
 imitate animal fibre. 
 
 In the very centre of the lock there is a small circular 
 opening, resembling the pupil of the eye, and serving to admit 
 the key, just as the pupil admits light. Around this pupil, if 
 we may so call it, are ranged some twenty thin steel slides 
 which move in channels, up and down which they slide. 
 Round the circumference of the lock are a corresponding 
 number of spiral springs, each of which presses on the base of 
 a slide, and forces it towards the centre. 
 
 The reader will now see that the radiating slides of the lock 
 represent the radiating fibres of the iris, and that the spiral 
 springs represent the circular fibres. Both perform the same 
 office, the steel slides regulating the size of the aperture, and 
 the spiral springs pressing them all towards the centre. The 
 key of the lock answers the same purpose as does light in the 
 eye, which by its mysterious pressure enlarges or contracts the 
 pupil. 
 
 This is not the place to describe this very ingenious lock in 
 detail, but I may state that it has never been picked. Even 
 Mr. Hobbs, who tried it for twenty-four hours, gave it up, and, 
 when he saw the interior mechanism, said that if he had tried 
 for a month he should have made no progress. This is an 
 unconscious testimony to the wisdom of following Nature in Art. 
 
 THE MAGIC LA.NTERN. 
 
 WE are all familiar with the Magic Lantern, whether it may 
 take the form of the mere child's toy, be developed into Dis- 
 solving Views, or throw black shadows on a curtain, in which 
 case it is called by the name of Chinese Shadows. In all these 
 cases the principle is the same. First we have a light behind 
 the object whose reflection is to be seen. Next we have the 
 object itself, and lastly the surface upon which it is reflected. 
 As to the variety of mirrors, lamps, and lenses which are used 
 to produce different effects, we may put them aside as foreign to 
 our present purpose.
 
 THE BROCKEN SPECTRE. 
 
 295 
 
 Generally the object is reflected upon a white curtain or 
 sheet, but sometimes, when a specially weird-like effect is 
 needed, a cloud of thick smoke takes the place of the sheet, and 
 
 MAGIC LANTERN. 
 
 upon it the reflection is shown, as seen in the accompanying 
 illustration. 
 
 NATURE has her Magic Lanterns as well as Art, and won- 
 derful things they are sometimes, the well-known Brocken 
 Spectre being an excellent example. It is not, however, neces- 
 sary to visit the Brocken in order to see this apparition, for I 
 have seen it in perfection in England. 
 
 Many years ago, when living in Wiltshire, I went before 
 daybreak to the top of a very high conical hill. The morning 
 mist was so thick that I could scarcely see my way up the hill. 
 When I reached the summit, I stood there for some time, try- 
 ing to see the landscape, but the mist was so thick that I could 
 barely tell the points of the horizon by the brighter look cast 
 by the coming Day in the east. 
 
 I was looking westward, when suddenly the sun rose behind 
 me, and I saw the Brocken Spectre as I have sketched it in 
 the accompanying illustration. It was a gigantic shadow of 
 myself, projected on the mist, just as a Magic Lantern projects 
 the image on a sheet or a smoke-cloud. Of course my gestures 
 were repeated, and it really looked almost awful to see this 
 gigantic spectral figure set in the mist.
 
 296 NATURE'S TEACHINGS. 
 
 Perhaps the most extraordinary part of it was the enormous 
 halo of rainbow colours round the head. No matter where I 
 moved, the halo surrounded the head of the image, its colours 
 being comparatively bright near the centre, and becoming 
 gradually paler towards the circumference. 
 
 Another point about this natural Magic Lantern ought to be 
 mentioned. 
 
 Wishing to show a friend the extraordinary sight of a 
 Brocken Spectre, I took him up the hill on a misty day like 
 that which has been briefly described. According to surmise, 
 two spectres appeared instead of one, but the halo was not 
 doubled as well as the shadow. I could see my friend's shadow, 
 
 BROCKEX SPECTRE. 
 
 and he could see mine. But, although the halo was as bright 
 as before, each of us could only see it encircling his own head. 
 We stood as close to each other as we could, we moved apart as 
 far as the nearly conical top of the hill would allow, and in 
 both cases each of us could only see his own halo. 
 
 Perhaps the reader may remember the wonderful spectre- 
 scene drawn by Mr. Whymper, and viewed from the Matter- 
 horn just after the accident which had killed several of his 
 companions in the ascent of the hitherto impregnable peak. In 
 the mist there suddenly appeared three vast dark crosses enclosed 
 in an oval. Considering the highly-strung nerves of the sur- 
 vivors, it was no wonder that they were all shaken by such an
 
 THE SPECTROSCOPE. 297 
 
 appearance, and that the guides were for a time too frightened 
 to proceed. 
 
 THE SPECTROSCOPE. 
 
 NEXT we come to one of the most astonishing and beautiful 
 optical instruments ever made by the hand of man. It is called 
 the Spectroscope, because it deals with a certain arrangement 
 of rays which is called a " spectrum." Many years ago 
 Newton discovered the cause of the lovely colours which 
 deck the rainbow, and the fact that, by passing a ray of 
 white light through a prism, it was decomposed into seven 
 colours, which invariably came in the following order Red, 
 Orange, Yellow, Green, Blue, Indigo, and Violet. He also 
 discovered that, by looking at that coloured band through 
 another prism arranged in a different manner, the decomposed 
 rays were again brought together, and white light was the 
 result. 
 
 Newton had thrown the light on the prism through a round 
 hole, but some time afterwards Dr. Wollaston employed a 
 narrow slit for the purpose, and then found that the spectrum 
 was traversed by dark lines which never changed their places. 
 On these lines depend all the discoveries that have been made 
 by the aid of the Spectroscope. The chief of them are designated 
 by the letters of the alphabet. (See page 300.) 
 
 It was soon found out that if burning gases were viewed 
 with the Spectroscope, lines were still seen, but they were 
 bright instead of dark, and that they invariably occupied the 
 place of one or more of the dark lines shown by the spectrum 
 of sunlight. Then it was discovered that these burning gases 
 absorbed or stopped out the light in the solar spectrum, and 
 from that moment the science rapidly advanced. 
 
 At the present day the Spectroscope not only determines the 
 metals which exist in the sun, but also those of the fixed stars. 
 It even analyzes the constitution of double stars, and shows the 
 reason why one star should be red and the other green. 
 
 One of the most astonishing discoveries in astronomy was 
 due to the Spectroscope. 
 
 During the month of May, 1866, one of the stars in the 
 Northern Crown (Corona Borealis) was seen to undergo a rapid 
 change. It was originally one of the tenth magnitude, but in
 
 298 
 
 NATURE S TEACHINGS. 
 
 a short time increased in size and brilliancy until it nearly 
 equalled Sirius, Capella, or Vega. It remained bright for some 
 time, and then rapidly faded until it resumed its former size. 
 
 How this change was effected we never should have known 
 but for the Spectroscope. No sooner, however, was this instru- 
 ment pointed at the star than there appeared in the spectrum 
 the three well-known lines red, green, and violet which 
 denote burning hydrogen. There was no doubt on the matter, 
 and the Spectroscope showed us that we were witnessing a 
 conflagration the like of which was never seen or scarcely 
 imagined. 
 
 Supposing our sun, which is known to be one of the stars, 
 and about which there are vast volumes of hydrogen gas, were 
 
 to blaze out in a similar manner, the result would be that the 
 whole of the planets would be consumed in a few seconds, and 
 converted into gases. In an instant every living thing would 
 be swept off the surface of the earth by this fearful heat, and, 
 as Mr. Roscoe says, " our solid globe would be dissipated in 
 vapour almost as soon as drops of water in a furnace." 
 So, as Mr. Huggins observes, the old nursery rhyme, 
 
 " Twinkle, twinkle, little star, 
 How I wonder what you are,"
 
 BESSEMER STEEL. 299 
 
 is no longer tenable, for we really do know the composition of 
 the stars. 
 
 The Spectroscope not only tells us the substance of which the 
 sun and the most distant stars are made, but gives us the same 
 information about the " gay motes that people the sunbeam." 
 It tells us that they are common salt in very minute particles. 
 They have been dashed into the air by the winds as spray, and 
 then dispersed over the whole globe. This is one reason why 
 we have so much salt in our bodies, and why the blood and 
 the tears are so salt. 
 
 IT is also applied to the arts. The well-known Bessemer 
 process consists in pouring melted iron into a peculiarly shaped 
 vessel called a "converter," and blowing air through it for 
 the purpose of burning out the carbon. From the mouth of 
 the converter issues a volume of magnificent flames, and at a 
 certain moment tbe skilled workman who directs the process 
 inverts the vessel and pours out the steel. A very few seconds 
 too soon or too late would spoil the whole of the metal, in the 
 former case it being simply brittle cast-iron ; and, in the second, 
 becoming so thick that it could not be poured out. 
 
 Only a few workmen could judge rightly the exact point 
 at which to shut off the air-blast. They watched the flame, 
 and by some change in it, too slight to be noticed by any 
 except experienced eyes, knew the moment when the iron was 
 converted into steel. 
 
 Such men could, of course, demand any wages they liked, 
 and, by striking, stop the whole works. The Spectroscope, 
 however, performed this delicate discrimination far better than 
 the best workman. When directed to the flame, the bright 
 lines indicating carbon are seen in the spectrum. When the 
 blast has continued for some twenty minutes, the carbon lines 
 suddenly disappear, showing that the carbon has been burned 
 out, and giving to the workman the signal to shut off the air- 
 blast. 
 
 ANOTHER discovery was, that liquids gave dark lines, 
 technically termed absorption bands, of different widths and in 
 different parts of the spectrum. Even liquids which had no 
 perceptible colour threw bands as bold as those which were
 
 300 
 
 NATURE'S TEACHINGS. 
 
 coloured, while coloured liquids threw totally different bands, 
 irrespectively of their own colour. 
 
 For example, the green colouring matter of leaves, called 
 chlorophyll, throws a single broad band on the extreme left 
 i.e. across the red part of the spectrum so far back, indeed, 
 that it is not easily seen at first. 
 
 Then, suppose that we make some pale solutions of red sub- 
 stances, such as carmine, magenta dye, port wine, logwood, 
 permanganate of potash, and blood, it is possible to have them 
 so exactly resembling each other that not even the microscope 
 can discriminate between them ; yet the Spectroscope instantly 
 detects the colouring matter of each solution. 
 
 The instrument is, therefore, invaluable in detecting adul- 
 terations of wine. For example, supposing that red wine is 
 
 SPECTRUM OP SUNLIGHT, OB SOLAR SPECTRUM. 
 
 SPECTRUM OF BLOOD. 
 
 suspected of owing its redness to logwood, and not to the 
 genuine grape, a drop is mixed with water and viewed through 
 the Spectroscope, which instantly tells whether the colouring 
 matter is grape or logwood. And as, by photography, the 
 spectrum can be exactly copied, an indelible record is procured 
 of the true nature of the object. 
 
 So marvellously delicate is the instrument with regard to 
 blood, that it detects the thousandth part of a grain of colouring 
 matter in a blood-stain. 
 
 If upon the spectrum were printed the word BLOOD in the 
 largest and blackest of capitals, it could not be more legible to 
 an ordinary reader than are the two blood-bands to the eye of a 
 spectroscopist. There is nothing like them in nature, and 
 whether it be by association of ideas, or by absolute fact, these 
 two bars have a strangely menacing look about them. Not 
 only that, but if the blood should be that of a person suf- 
 focated with carbonic acid gas, the Spectroscope will say so. 
 
 Some years ago a man owed his life to the Spectroscope, A
 
 THE POCKET SPECTROSCOPE. 301 
 
 mysterious murder had been committed, and the police had 
 arrested a man who was found near the spot. He could give 
 no intelligible account of himself, and the sleeves of his coat 
 and a part of his waistcoat were deeply stained with a red sub- 
 stance just like clotted blood. A piece of each garment was 
 cut off and given to a well-known spectroscopist, who tried the 
 red matter in the instrument, and at once declared it not to be 
 blood. What it was he had not time to ascertain, so he sent 
 it to a brother in science, who, after examination, pronounced 
 it to be red gum. 
 
 By degrees, the man, who had been intoxicated when arrested, 
 stated that he had been to see a friend who was a journeyman 
 hatter. It was then found that he had been leaning on the 
 workman's board, and so had carried off some of the gum- 
 mastic with which hats are stiffened. Had it not been for the 
 infallible Spectroscope, the man might have lost his life. 
 
 Thus we see that the Spectroscope is the elephant's trunk of 
 optics, equally fitted for the greatest and smallest, the farthest 
 and nearest, of objects. It is equally at home in earth and 
 sky. When attached to the telescope, it reveals the constituents 
 of the stars, and, when affixed to the microscope, it shows 
 us the colouring matter of a green leaf. It produces the best 
 steel, and detects adulteration in wine. And, lastly, as we 
 have seen, it turns lawyer, and settles the evidence by which 
 the life of a man is lost or saved. It can determine the purity 
 of the smallest coinage, and tell us why a star changes in 
 magnitude. 
 
 Yet all these wondrous revelations are made by a few prisms 
 and a magnifying-glass. I possess a Spectroscope, made and 
 presented to me by Mr. J. Browning, the celebrated optician. 
 This astonishing instrument is only three inches long, and 
 half an inch in diameter, so that it can be carried in the waist- 
 coat pocket. I always keep mine in a finger of a white kid 
 glove, which is amply sufficient for it. Yet it gives the spec- 
 trum of the sun with its principal lines, will detect the fraudu- 
 lent wine merchant, and could have decided whether the accused 
 man should be acquitted or hanged. 
 
 MARVELLOUS and mighty as is this engine, it lay concealed 
 in Nature ever since the sun's rays shone upon earth and a drop
 
 302 NATURE'S TEACHINGS. 
 
 of water existed. The Rainbow is nothing but a vast spec 
 trum, a transverse slice of which would be a good representa- 
 tion of the coloured band which is shown in the instrument. 
 It is prefigured in the ever-shifting rainbows of the water-fall 
 and fountain, which latter may even be seen in the fountains of 
 Trafalgar Square, while at the Crystal Palace their beauty has 
 long been noticed. 
 
 There is not a dewdrop which is not a miniature Spectro- 
 scope, as it glitters with its wondrous iridescence in the rays 
 of the rising sun ; there is not an opal with its shifting hues, 
 nor the splendour of the soap-bubble, nor the nacre of the 
 common river mussel or the ormer shell, which does not owe its 
 beauty to the same principles which govern the Spectroscope. 
 Every green leaf, and blue or pink or yellow petal, every vary- 
 ing tint of the mackerel sky, every blaze of sunset and blue- 
 grey of sunrise, owes its beauty to those wondrous laws of 
 light which had been hidden for so many centuries, until they 
 were unveiled by the simple prism of the Spectroscope. As in 
 so many instances, the revelation lay concealed until the coming 
 of the revealer, whose inspired hand raised the dark veil ot 
 centuries. 
 
 THE THAUMATROPE. 
 
 MIDDLE-AGED persons will recollect that since the days of 
 their childhood a great variety of optical apparatus has been 
 invented ending in the word " trope." This is a Greek word, 
 signifying to turn, and is given to the instruments because 
 they revolve. 
 
 All these toys and they may some day become more than 
 toys depend on a curious property of the human eye. The 
 reader will remember that in the description of the human eye, 
 as compared with the camera obscura as applied to pho- 
 tography, it was mentioned that the image was thrown from 
 the front to the back, and in the one case was received on a 
 naturally sensitive membrane, and in the other on a film ren- 
 dered artificially sensitive by chemical means. This mem- 
 brane is called the " retina," because it not only receives the 
 impression, but retains it for some little time after the object 
 is removed. It has been calculated that the duration of the 
 image is about the eighth part of a second.
 
 THE RETINA. 303 
 
 Thus the eyelids are perpetually and unconsciously closing 
 and opening with a rapid movement, popularly called " wink- 
 ing." This movement is for the purpose of cleansing the eye- 
 ball, and, were it not for the image-retaining power of the 
 retina, we should pass a considerable part of our time in abso- 
 lute darkness. As it is, the impression of external objects on 
 the retina lasts longer than the time occupied in winking, and, 
 in consequence, we are not conscious that any interval of dark- 
 ness has elapsed. 
 
 Again, when we have been looking steadfastly at an object, 
 and then move our eyes, the image of that object is seen in the 
 new focus; and it is worthy of notice that such object is 
 always seen in its " complementary " colour. For example, if 
 we have been looking at a scarlet spot, and suddenly move our 
 eyes, we shall see a spot exactly similar in size and shape, but 
 of green. 
 
 I well remember that when I was a boy I was reading with 
 almost feverish anxiety the green handbill of a travelling 
 circus, to which I hoped that I might be allowed to attend. 
 Having finished it, I asked for some note-paper, for the pur- 
 pose of putting my request in writing, but, to my astonishment, 
 mixed, perhaps, with a little irritation, all the paper supplied 
 to me was of a bright pink. For a time no arguments could 
 convince me that the paper was really white, until by degrees 
 the pick hue became paler and paler, and the paper assumed its 
 normal whiteness. 
 
 The fact was, that the eye had become saturated with the 
 green i.e. the blue and yellow rays and could see nothing 
 but their complementary colour, which was pink. 
 
 A good example of this property may be found in a lighted 
 stick, which, if rapidly whirled round, appears to form a con- 
 tinuous circle of fire. The reason of this is, that the impression 
 made on the retina by the fiery point does not cease until the 
 stick has again come round in its course. 
 
 Then there are those well-known chromatic tops, in which 
 are inserted pieces of bent wire. When the top is spun 
 these pieces of wire assume exactly the appearance of trans- 
 parent jugs, vases, glasses, and similar articles. A very pretty 
 illustration of this principle is given by a little machine, which 
 is made to revolve rapidly by means of a multiplying wheel.
 
 304 NATURE'S TEACHINGS. 
 
 Upon its surface are fixed little pins, with polished globular 
 steel heads, and, when the handle is turned, these heads form 
 the most beautiful and intricate figures with exact accuracy. 
 
 Another toy, called the Thaumatrope, or Wonder-turner, is 
 equally ingenious and beautiful, and is sufficiently simple to be 
 made by any one with a slight knowledge of drawing. A disc 
 of white cardboard is cut, and upon each side of it is portrayed 
 some object. If the disc be caused to revolve rapidly, these 
 two subjects will be seen at the same time, the image of each 
 being held on the retina long enough to allow the other to take 
 its place. 
 
 Some very beautiful combinations may be made by means of 
 this instrument. For example, a horse may be on one side, and 
 a man on the other, and, by spinning the disc, the man will be 
 seen mounted on the horse. Then we may have a boat on one 
 side, and a rower with his oars on the other. Similarly a mouse 
 can be put into a trap, or a bird into a cage. 
 
 The reader must remember that these subjects must be 
 drawn as if they were upside down with regard to each other, 
 so that the man who is to ride the horse is drawn as if he were 
 standing on his head, and the mouse which is to enter the trap 
 looks as if it were lying on its back. 
 
 The most simple manner of spinning the disc is by means of 
 two threads, each being inserted near the edge of the disc, and 
 exactly opposite each other. 
 
 A very ingenious modification of the Thaumatrope is made 
 by inserting at one side of the disc two strings, of which one is 
 elastic. It is evident, then, that by lengthening or shortening 
 the elastic string, the axis can be changed, and the objects on 
 the opposite sides placed in positions relatively different from each 
 other. Thus the jockey may be made to jump on and off his 
 horse, the bird to go in and out of its cage, the mouse to enter 
 the trap, and so on. This simple invention allows of infinite 
 combinations, so that a tree may be made to sprout, a man to 
 move his limbs, and a bird to flap its wings. It was invented, 
 I believe, by Dr. Paris, author of " Philosophy in Sport made 
 Science in Earnest." 
 
 On the right hand of the illustration are seen three figures, 
 each representing a means of obtaining an ocular delusion 
 through the principle of which we are now treating.
 
 THE ZOETROPE. 
 
 305 
 
 The lower figure is called the Zoetrope, or Wheel of Life. 
 As the reader may see, it consists of a hollow cylinder, revolving 
 on a centre, and having within it a series of figures. When the 
 wheel revolves, and the figures are viewed through the slits, 
 each figure seems to be in lifelike motion, whence the name 
 of Zoetrope. In the present case the figures are those of boys 
 jumping over posts. 
 
 The mode in which this efiept is produced is as follows : 
 Suppose that a boy were really to jump over a post, he would 
 go through a series of motions, and his body be placed in a 
 certain series of positions, before he cleared the post. Suppos- 
 ing, then, that several points were chosen in his course, and his 
 
 WHEEL ANIMALCULE. 
 
 PHAXTASMASCOPE. CHROMATROPE. 
 
 ZOETROPE. 
 
 body drawn as it would appear at these points, and the drawings 
 placed in their proper order in the Zoetrope, it is evident that 
 the figures must appear in movement. Before the retina loses 
 the image of the boy standing in front of the post, it takes in that 
 of the boy stooping, with his hands on the top of the post, and 
 so on until he has reached the ground on the opposite side. 
 
 Another mode of producing the same effect, called the 
 Phantasmascope, is seen above the zoetrope. In this case the 
 images are placed on the inside of the disc, which is held 
 opposite a mirror, and the figures viewed through the slits. 
 
 The last of these figures is the rather complicated one, like 
 
 X
 
 306 NATURE'S TEACHINGS. 
 
 the back of an " engine-turned " watch. This is called the 
 Chromatrope, or Wheel of Colour, and is always a favourite 
 object in a magic lantern. It consists of two circular plates of 
 glass, one upon the other, and painted in variously coloured 
 curved lines, as seen in the illustration. When the image is 
 thrown upon a screen, and the glass plates turned in opposite 
 directions, a most singular and beautiful effect is produced. The 
 lines, unless the eye follows them very closely, disappear, and 
 torrents of coloured spots seem to pour from the centre to the 
 circumference, or vice versa, according to the direction in 
 which the glass wheels are turned. So perfect is the illusion, 
 that it is almost impossible to believe that the movement is 
 only circular, and not spiral. 
 
 Now we will pass from Art to Nature. The figure on the 
 left hand of the same illustration represents part of one of the 
 Wheel Animalcules, so called because they look exactly as if 
 the fore-part of their bodies were furnished with two delicate 
 wheels, running rapidly round, and evidently moving or stop- 
 ping at the pleasure of the owner. 
 
 Soon after the powers of the microscope became known, 
 these Wheel-bearers were discovered, and for a long time they 
 were thought to have a pair of veritable revolving wheels upon 
 their heads. They were naturally held in high estimation, as, 
 although almost every kind of lever can be found in the animal 
 world, a revolving wheel had never been seen. However, as 
 the defining powers of the microscope improved, the so-called 
 wheels were found not to be wheels at all, but stationary 
 organs, and that their apparent revolution was nothing but an 
 optical delusion. 
 
 The wheels are, in fact, two discs, around the edges of which 
 are set certain hair-like appendages, called " cilia," from a 
 Latin word signifying the eyelashes. Each of the cilia has an 
 independent motion of its own, and, as they bend in rapid and 
 regular succession, they produce an effect on the eye similar to 
 that of a revolving body. As for the animal itself, they 
 produce a double effect, either acting as paddles, and forcing the 
 animal through the water, or, when it is affixed to some object, 
 causing a current which drives into its mouth the minute beings 
 on which it feeds.
 
 WHEEL ANIMALCULES. 30? 
 
 The particular species of Wheel-bearer whose mouth is here 
 shown is called scientifically Limnias ceratophylli. It derives 
 the latter name from the fact that it is mostly found on the 
 submerged stems and leaves of the Horn wort (Ceratophyllum) , 
 which is very common in ponds and slow streams. The 
 creature is, however, to be found on the water-growing plants, 
 and Mr. Gosse, in his " Evenings with the Microscope," gives a 
 very full and graphic account of itself and its habits. 
 
 He specially mentions the use of the wheels, and, by 
 dissolving a little carmine in the water, had the pleasure of 
 seeing the coloured granules swept into the mouth by the 
 current caused by the cilia through the jaws, and so into the 
 stomach. 
 
 x 2
 
 USEFUL AETS. 
 
 CHAPTER I. 
 
 PRIMITIVE MAN AND HIS NEEDS. EARTHENWARE. BALL- 
 AND-SOCKET JOINT. TOGGLE OR KNEE JOINT. 
 
 Contrast between Savagery and Civilisation. Manufacture of Weapons. 
 Earthenware of Art. Sun-baked Vessels. Earthenware of Nature. Nest 
 of Pied Grallina. Analogy with the Babylonish Brick. Nest of the Oven- 
 bird. A partitioned Vessel. Necked earthenware Vessels. Nests of 
 Eumenes, Trypoxylon, and Pelopoeus. Proof of Reason in Insects. The 
 Ball-and-socket Joint. "Bull's-eye" of Microscope. The human Thigh- 
 bone. Vertebrae of the Serpents and their Structure. The Sea-urchin and 
 its Spines. Legs and Antennae of Insects. The Toggle or Knee Joint, and 
 its Use in the Arts. The hand Printing-press and the Toggle-ioint. The 
 human Leg and Arm. Power of the natural Toggle-joint. Fencing and 
 Boxing. Heads of Carriages. "Bowsing" of Ropes. Leaf-rolling Cater- 
 pillars. 
 
 IN the primitive ages of Man the aids to civilisation were 
 very few and very rude. Some of them, especially those 
 which relate to hunting and war, have already been mentioned, 
 and we now have to deal with some of those which bear upon 
 domestic life. 
 
 Here we are in some little difficulty, for it is not very easy 
 to draw the line where domestic life begins, or the mode in 
 which it shall be defined. We may at all events connect 
 domestic life with a residence of some sort, and may, in conse- 
 quence, neglect all such primitive savages as need no domestic 
 implements. 
 
 Such, for example, are the few surviving Bosjesmans of 
 Southern Africa, not one of whom ever made a tool or an 
 implement, or looked beyond the present day. The genuine 
 Bosjesman can make a bow and poison his arrows, and he can 
 light a fire ; but there his civilisation ends. He cannot look 
 beyond the present hour, he has not the faintest notion of
 
 EARTHENWARK. 309 
 
 making a provision for the future, nor did his wildest imagina- 
 tion ever compass the idea of a pot or a pan. 
 
 He kills his prey, and, if hunger be very pressing, he wif 
 eat it at once without waiting for the tedious ceremony of 
 cooking ; or at the best will just throw the meat upon the fire, 
 tear it to pieces with his teeth, and swallow it when it is 
 nothing but a mass of bleeding flesh, charred on the outside, 
 and absolutely raw within. The Bosjesman has not even a tent 
 which he can call his own, any bush or hole in the ground 
 answering for a house as long as he wants it, and then being 
 exchanged for another. 
 
 As far as we know, the only trace of civilisation in the 
 Bosjesman is his manufacture of weapons, and even his bow 
 and arrows are of the rudest and clumsiest forms. Nor is it 
 likely that he will ever advance any further ; for, as is the wont 
 of all savage tribes, he is disappearing fast before the presence 
 of superior races, and will shortly be as extinct as the Tas- 
 manians, the last of whom died only a few years ago. 
 
 EARTHENWARE. 
 
 THE advent of real civilisation seems to depend largely upon 
 the construction, not of weapons, but utensils, and the most 
 useful of these are intended either for the preparation or the 
 preservation of food. That such vessels should be made of 
 earth is evident enough, and it is worthy of remark that the 
 rude earthenware pot of the naked savage and the delicate 
 china of Sevres should both be products of the earth, and yet 
 be examples of the opposite ends of civilisation. 
 
 The most primitive earthenware vessels were simply baked 
 in the rays of the sun, the use of fire for hardening them bein^ 
 of later date. Rude and simple as they are, some of these 
 vessels possess tolerable strength, and can answer every purpose 
 for which they are intended. I possess several pots made by 
 the aborigines of the Essequibo district. They are very thick 
 and heavy in proportion to their dimensions, and are still so 
 fragile that I have been obliged to bind them with string when- 
 ever they are moved. 
 
 Simple as they are, however, they are pleasing to the eye, 
 chiefly, I presume, because they are made for a definite office,
 
 310 
 
 NATURE S TEACHINGS. 
 
 and fulfil it, and have no pretence about them. Then, as 
 they are moulded by hand alone, without any assistance from 
 machinery of any kind, even a wheel, the individuality of the 
 maker is stamped upon them, and no two are exactly alike either 
 in form, colour, or ornament. A couple of these rude vases are 
 to be seen on the right hand of the accompanying illustration. 
 
 ON the left hand of the same illustration are shown two 
 examples of earthenware vessels made by birds, which aro 
 nearly, if not quite, as good as those made by the hands of 
 civilised man. 
 
 The upper figure represents the nest of the Pied Grallina 
 (Grallina Australis), a bird which, as its specific name implies, 
 is a native of Australia. 
 
 This nest is formed chiefly of clay, but a quantity of dried 
 
 NEST OP PIED GRALLISA. 
 NEST OP OVEX-BIRD. 
 
 PRIMITIVE EAF.THENWARE. 
 
 grass is always mixed with it, and serves to bind it together. 
 If one of these nests be broken up, and compared with the 
 bricks of which ancient Babylon was built, it will be found 
 that they are almost identical in material, and that both are 
 merely baked in the sun. In form it so closely resembles an 
 Essequibo jar in my possession, that if it were removed from 
 the branch, and similarly coloured, it would not be easy to 
 distinguish the one from the other. 
 
 BELOW this is the nest of the Oven-bird of South America 
 (Furnanusfuliginosus), a bird allied to our common creeper. 
 The drawing was taken from a specimen in the British 
 Museum. 
 
 Like the nest of the Grallina, it is placed upon some hori-
 
 EARTHEN NESTS. 311 
 
 zontal bough, and fixed so firmly that it cannot fall except by 
 being broken to pieces. Not being afraid of man, the Oven- 
 bird often chooses a beam in some outhouse for a resting-place, 
 and has been known to build even on the top of palings. As 
 may be seen by reference to the illustration, the nest is a very 
 conspicuous one, and concealment is almost impossible. 
 
 As in the Grallina nest, the material is remarkably hard 
 and firm, as indeed is necessary, to allow it to withstand 
 the effects of the rain-torrents which fall during the wet 
 seasons of the year. 
 
 There is a curious analogy in this nest with many articles 
 of earthenware. Not only among ourselves, but among un- 
 civilised races, earthenware vessels are constructed with 
 partitions, so as to divide one portion from another. If one 
 of these nests be cut open, it will be found to have a sort of 
 partition Avail across the interior, rising nearly to the top of 
 the dome, and so dividing it into two parts. The wall also 
 answers another purpose i.e. that of strengthening the entire 
 structure. Within the inner chamber is the real nest, which 
 is lined with a thick layer of feathers, the outer chamber being 
 bare, and, as it is thought, being occupied by the male. 
 
 WK now come to pottery of a more elaborate shape. Both 
 in the Grallina nest and the earthen pot of the Essequibo 
 Indian we have a vessel with a mouth nearly as wide as its 
 greatest diameter, arid with a lip which is very slightly turned 
 over. There are, however, many varieties of pottery in which 
 the neck is narrow and long, and the lip is boldly formed. 
 Some examples of this form are given on the right hand of the 
 accompanying illustration. 
 
 Ox the left hand are shown some nests of a solitary wasp 
 belonging to the genus Eumenes. It is a British insect, 
 but seems to have been little noticed, except by professed ento- 
 mologists. 
 
 It especially haunts heather, and affixes to the stems of the 
 plant its little globular nests, which are made of mud, and 
 shaped as seen in the illustration. Perhaps some of my readers 
 may have seen the " Napier Coffee Machine," which draws the 
 coffee into a glass globe furnished with a short neck. The
 
 312 
 
 NATURE S TEACHINGS. 
 
 globe is shaped exactly like the nest of our Eumenes, and, 
 when I first saw one, I could not remember why its shape was 
 so familiar to me. 
 
 As is the case with the birds' nests which have been men- 
 tioned, the mud of which the walls are built is of a most tena- 
 cious character, and, when dried in the sun, can resist the 
 heaviest rain. The cells are intended as rearing-places for the 
 young, only a single egg being placed in each cell, which is 
 then stocked with small caterpillars by way of food. 
 
 THERE is a South American insect also belonging to the 
 solitary wasps, and remarkable for building a round nest exactly 
 similar in material, and nearly identical in shape, with that of 
 
 OF EUMENES. 
 
 ANCIENT NECKED POTTEBY. 
 
 the Eumenes. Its scientific title is Trypoxylon aurifrons. The 
 nest of this insect has a much wider mouth than that of the 
 Eumenes, and exactly resembles the upper left-hand jar in 
 the illustration. 
 
 ANOTHER South American solitary wasp, belonging to the 
 genus Pelopoeus, makes nests of similar material, but nearly 
 cylindrical in shape instead of globular. The ne&t is built 
 up of successive rings of moistened and well-kneaded clay, 
 exactly as human houses are built by bricklayers. Indeed, 
 the process of making a Pelopoeus' nest has been happily com- 
 pared to that of building a circular chimney. 
 
 I may as well mention here that the name Pelopoeus is
 
 BALL-AND-SOCKET JOINT'S. 
 
 313 
 
 formed from a Greek word signifying mud, and that the entire 
 word may be translated as " mud- worker." 
 
 As a proof that these insects possess reason as well as instinct, 
 Mr. Gosse mentions that one of them, instead of making her 
 nest for herself, utilised an empty bottle, and, after storing it 
 with spiders, stopped up the mouth with clay. Finding, after 
 an absence of a few days, that the nest had been disturbed, she 
 removed the spiders, inserted a fresh supply, and then closed 
 the mouth as before. 
 
 BALL-AND-SOCKET JOINT. 
 
 will now see how some of the most useful mechanical 
 inventions have had their prototypes in Nature. 
 
 There is, for example, the well-known " Ball-and-socket 
 joint," without which many of our instruments, especially 
 those devoted to optical purposes, would be impracticable. 
 
 HIP-JOrNT. 
 
 SPINES OP SEA-URCHIJT. 
 VEBTEBB.K OF SNAKE. 
 
 BALL-AND-SOCKET JOINT 
 OF MICROSCOPE. 
 
 The figure on the right hand of the illustration represents the 
 " bull's-eye " of my own microscope. It will be seen that there 
 is a ball half sunk in a cup, so that it can be turned in any 
 direction. In point of fact, the upper part of the ball is nearly 
 concealed by another cup, but, in order to show the structure, 
 the upper cup has been removed. "Who was the inventor of 
 the ball-and-socket joint I do not know, but I have little doubt 
 that he must have had in his mind many natural examples of 
 this joint, three of which are represented in the illustration.
 
 NATURES TEACHINGS. 
 
 ON the left hand are seen the upper part of the human thigh- 
 bone and that part of the hip-bone into which it fits. 
 
 The reader will see that at its upper end the bone takes 
 rather a sharp turn, and is then modified into a ball. This 
 ball fits into a corresponding socket, technically named the 
 " acetabulum," and is thereby endowed with freedom of motion 
 in almost every direction. Generally we do not practise our 
 limbs sufficiently to develop that full freedom, but those who 
 have seen any good professional acrobats must have been 
 struck with the wonderful mobility of which the human body 
 is capable. 
 
 The socket is not a deep one, but dislocation of the hip is 
 exceedingly rare, the bone being held in its place by three 
 powers. The first is due to a short ligament, which, however, 
 does not always exist, but, when it is present, is useful in 
 retaining the bone in its place. Then there is the contractile 
 power of the thigh muscles, which are always forcing the ball 
 into the socket. Lastly, there is the pressure of the atmosphere, 
 a force which is seldom taken into consideration, but which has 
 great influence on many parts of the human frame. This part 
 of the subject will be resumed when we come to treat of 
 Atmospheric Pressure. 
 
 The arms are jointed to the shoulder-blades in a very similar 
 manner, the upper arm-bone, or " humerus," being furnished 
 with a rounded end, and fitting into a cup-like cavity in the 
 shoulder-blade, or "scapula." This formation can easily be 
 seen by separating the different bones of a shoulder of 
 mutton. 
 
 AT the bottom of the illustration are given two vertebrae of 
 a snake, separated in order to show their structure. It will be 
 seen that each joint has a ball in front and a socket behind, 
 thus giving the creature that wonderful flexibility which is 
 quite proverbial, and without which it could not seize its 
 prey. 
 
 The following eloquent passage is taken from Professor 
 Owen's work entitled " The Skeleton and the Teeth : " 
 
 " Serpents have been regarded as animals degraded from a 
 higher type, but their whole organization, and especially their 
 bony structure, demonstrate that their parts are as exquisitely
 
 VERTEBRAE OF THE SERPENT. 315 
 
 adjusted to the form of their whole, and to their habits and 
 sphere of life, as is the organization of any animal which we 
 call superior to them. 
 
 " It is true that the serpent has no limbs, yet it can out- 
 climb the monkey, outswim the fish, outleap the Jerboa, and, 
 suddenly loosening the coils of its crouching spiral, it can spring 
 into the air and seize the bird upon the wing: all these 
 creatures have been observed to fall its prey. 
 
 " The serpent has neither hands nor talons, yet it can out- 
 wrestle the athlete, and crush the tiger in the embrace of its 
 ponderous overlapping folds. Instead of licking up its food as 
 it glides along, the serpent uplifts its crushed prey, and presents 
 it, grasped in the death- coil as in hand, to its slimy, gaping 
 mouth. 
 
 " It is truly wonderful to see the work of hands, feet, and 
 fins performed by a modification of the vertebral column 
 by a multiplication of its segments with mobility of its ribs. 
 But the vertebrae are especially modified, as we have seen, to 
 compensate, by the strength of their numerous articulations, 
 for the weakness of their manifold repetition, and the conse- 
 quent elongation of the slender column. 
 
 " As serpents move chiefly on the surface of the earth, their 
 danger is greatest from pressure and blows from above ; all the 
 joints are fashioned accordingly to resist yielding, and swt in 
 pressure in a vertical direction ; there is no natural undulation 
 of the body upwards and downwards it is permitted only 
 from side to side. So closely and compactly do the ten pairs 
 of joints between each of the two hundred or three hundred 
 vertebrae fit together, that even in the relaxed and dead state 
 the body cannot be twisted except in a series of side coils." 
 
 THE upper right-hand figure represents a portion of the 
 shell of an Echinus, or Sea-urchin, together with two of the 
 spikes. 
 
 The reader will remember that in the description of the 
 Heart-urchin, and the mode in which it dug its way into the 
 sand, the peculiar mobility of the spines was mentioned. How 
 that mobilicy is produced we shall now see. 
 
 If a living Sea-urchin can be procured, and placed in a 
 glass vessel tilled with sea- water, it will at once be seen that
 
 316 NATURE'S TEACHINGS. 
 
 its surface is thickly covered with spines. In some species 
 these spines are as thick as ordinary drawing pencils ; but in 
 most of those which are found on our shores they are very slight, 
 and scarcely longer than darning-needles. They are in almost 
 perpetual motion, and generally have a sort of revolving move- 
 ment, the base being the pivot. 
 
 Now, if we take a dried shell of the Sea-urchin, we shall 
 find that the spines will come off with a touch, and, indeed, to 
 preserve one with all the spines complete is a most difficult 
 business. Let us, therefore, pull one from its attachment, and 
 examine its base. This will be found to be swollen into a cup- 
 like form, as seen in the illustration ; and, if we look at the 
 spot whence it came, we shall see that there is a little, rounded, 
 polished prominence, exactly fitting into the cup, just as the 
 ball of the human thigh-bone fits into the acetabulum. It 
 has also its ligament to keep it in its place, and its same set of 
 muscles that move it, and is altogether a most wonderful piece 
 of mechanism. There are in some species of Echinus about 
 four thousand of these spines. 
 
 THE legs of an insect afford excellent examples of the ball- 
 and-socket principle, the socket being on the body, and the 
 ball on the base of the leg. Some of our largest insects such, 
 for example, as the common Stag-beetle exhibit this principle 
 very well. I have now before me a Stag-beetle which has been 
 dead for many years, and is quite dry and hard. Yet I can 
 rotate the legs almost as freely as if the beetle had been 
 just killed, so easily do the joints work. Even the antennae, 
 which are affixed to the head by a similar joint, move about 
 by their own weight on merely changing the position of the 
 insect. 
 
 These are only a few of the many natural examples of the 
 Ball-and-socket joint, but they are sufficient for our purpose. 
 
 THE TOGGLE OR KNEE JOINT. 
 
 ANOTHER most useful invention now comes before us, called 
 the Toggle-joint, or Knee-joint, the latter name being given 
 to it on account of its manifest resemblance to the action of 
 the human knee.
 
 THE TOGGLE OR KNEE JOINT. 
 
 317 
 
 This joint is shown in the illustration. It consists of two 
 levers, jointed together at one end, and having the other ends 
 jointed to the objects which are to be pressed asunder. It will 
 be seen that if the centre of the Toggle be pushed or pulled in 
 the direction of the arrow, so as to straighten the levers, the 
 amount of pressure upon them is enormous. Such an appa- 
 ratus as this combines simplicity and power in a wonderful 
 manner, and is greatly used in machinery, especially in 
 presses, where the force is required to be great, but not of long 
 duration. 
 
 An ordinary two-foot rule, when bent, affords a good 
 example of the Toggle-joint, and will exert a wonderful 
 amount of force. 
 
 The illustration represents one of the common printing- 
 presses that are worked by hand. When the workman draws 
 
 8TBAIOHTVNI' 
 TOGGLK8. 
 
 BBNT 
 TOGGLES. 
 
 PRINTING-PRESS. 
 
 the handle horizontally, he causes the two portions of the 
 Toggle to approach a straight line. The upper half of the 
 Toggle being jointed to the fixed beam above, and the other 
 half to the movable plate or " platen " below, it is evident that 
 the latter will be pressed downwards with enormous force. 
 Indeed, so great is the power of this instrument, that a man 
 of moderate strength can exert a pressure of many tons. 
 
 WE now proceed from Art to Nature, and take first the 
 human knee, being the joint from which this piece of mecha- 
 nism has derived one of its names. 
 
 If the reader will look at the figure of the fencers, he will 
 see that the arm and leg are both Toggle-joints. In the one
 
 318 NATURE'S TEACHINGS. 
 
 who is standing on the defence they are bent, and in the 
 other, who has just made a longe, the Toggles of the right arm 
 and left leg are straightened. It is by the straightening of 
 these joints, and not by the action of stabbing, that the rapidity 
 and force of a thrust are achieved. 
 
 It is just the same in boxing. No one who has the least 
 knowledge of sparring strikes a round-handed blow, for, 
 putting aside the ease with which it is parried or avoided, 
 it has scarcely any force in it. When a boxer hits " straight 
 from the shoulder," he not only straightens the Toggle-joint 
 of his left arm, but that of his right knee also, so that the 
 force of the blow comes quite as much from the leg as the 
 arm. 
 
 It is by the right use of this joint that a small man, 
 provided he be an expert boxer, will easily conquer an ignorant 
 opponent who far surpasses him in size and weight. I have 
 seen in a sparring-match a man not only knocked down, but 
 fairly lifted off his feet, by a blow from a smaller opponent. 
 The blow took effect under the chin, and, as the boxer hit 
 exactly the right moment in straightening both limbs, a very 
 great force was exerted with little apparent effort. I do not 
 know which of the two combatants was the more astonished, 
 the one to find himself on his back without exactly knowing 
 how he got there, and the other to see his antagonist pros- 
 trate without exactly knowing how the thing was done. 
 
 The jointed apparatus by which the heads of carriages 
 are raised or lowered is a good example of the Toggle, and 
 exemplifies the force which a comparatively slight piece of 
 machinery can exercise. 
 
 ANOTHER form of the Toggle-joint is the process called by 
 sailors " bowsing " of rope. If a rope be fastened at both 
 ends, and then pulled in the middle, the ends are drawn 
 forcibly towards each other. This plan is mostly adopted in 
 getting up sails. When a sail, say the mainsail of a cutter, 
 has to be hoisted as far as it will go, the last few inches are 
 always very obstinate. The word is then given to "bowse." 
 The rope, or haulyard, is no longer pulled at the end, but a 
 turn is taken round the cleat, so that it does not give way. 
 The rope is then forcibly pulled away from the mast, when
 
 LEAF-ROLLING CATERPILLARS. 319 
 
 up goes the gaff a little higher. In this way, by repeated 
 bowsings, the gaff is coaxed, so to speak, up the mast, and 
 forced into its place. 
 
 Some of the leaf-rolling caterpillars act in a similar manner, 
 by alternately bowsing and shortening their lines. As, how- 
 ever, their mode of working will be described under another 
 heading, we will say no more of them at present.
 
 CHAPTER II. 
 
 CRUSHING INSTRUMENTS. THE NUT - CRACKERS, ROLLING- 
 MILL, AND GRINDSTONE. PRESSURE OF ATMOSPHERE. 
 SEED DIBBLES AND DRILLS. 
 
 Importance of Leverage in Crushing Power. Nut-crackers a Lever of the Second 
 Order. The Chaff-cutting and Tohacconists' Machines. Jaws of various 
 Animals. The Wolf-fish or Sea-wolf. The Rolling-mill and its Action. 
 Gunpowder-mills and Granulating Machine. The "Jacob's Ladder." 
 The Mangle and its various Adaptations. The Grindstone. Primitive 
 Grindstones of the Savage Races. The Kafirs and the Inhabitants of Pales- 
 tine. Ceasing of the Millstone. " Facing " of Millstones. Tusk of the 
 Elephant and its Structure. Its Tracings always preserved. Power of 
 Self-renewal. Pressure of Atmosphere. The Napier Coffee Machine. 
 The Cupping Instrument. The Pneumatic Peg. The Magdeburg Hemi- 
 spheres. Plane Surfaces of Glass or Metal. Suckers of the Cuttle-fish. 
 Foot of the Water-beetle. The Limpet. The Star-fish and its Mode of 
 Progression. The Sucking-fish and the Fables connected with it. Its real 
 Structure. Modification of the Dorsal Fin. The Gobies and Lump-fish. 
 The Gecko and Tree-frog. The Lampern and the Medicinal Leech. Seed 
 Dibbles and Drills. Labourers versus Machinery. Natural Dibble of the 
 Grasshopper. The Daddy Long-legs. Drills and Dibbles of the Ichneumon- 
 flies. A wonderful Specimen from Bogota. The Pelecinus and its Mode 
 of laying Eggs. 
 
 CRUSHING INSTRUMENTS. 
 
 AS we are on the subject of leverage, we will take some 
 examples of levers in Art and Nature, without, however, 
 even attempting to exhaust the topic. 
 
 On the right hand of the illustration is shown a very familiar 
 example of a lever, namely, nut-crackers, with a nut between 
 them. This useful implement is simply an adaptation of levers 
 of the second kind, the power being represented by the human 
 hand, the weight by the nut, and the fulcrum being the joint of 
 the instrument. 
 
 The common chaff-cutter, which is worked by hand, is 
 another familiar example of this kind of lever, and so is the knife 
 used by tobacconists in cutting cake Cavendish into threads,
 
 CRUSHING INSTRUMENTS. 
 
 321 
 
 and by druggists for similar purposes. In these instruments 
 the point of the knife is jointed to some fixed object, and 
 becomes the fulcrum ; the hand of the cutter supplies the power, 
 and the weight is the object which is being cut. It will be 
 seen that, by increasing the length of the handle, very great 
 power can be obtained. 
 
 Exchanging the power for weight, we have in the common 
 tongs, whether used for the coals or for sugar, a leverage of a 
 similar character, the weight moving over a greater space than 
 the power. A good example of this is to be found in the 
 deltoid muscle of the human arm. The muscle, which furnishes 
 the power, contracts about an inch, and, so doing, moves the 
 
 JAWS OP WOLF-PISH. 
 
 NUT -CRACKERS. 
 
 hand over some forty inches of space. It has been well stated 
 that if a man is able to hold in his hand, and with extended 
 arm, a weight of twenty-five pounds, the muscle must be exert- 
 ing a power of forty times as great, i.e. about a thousand 
 pounds. 
 
 THERE is little doubt that, in such Crushing Instruments as 
 have been mentioned, the idea has been taken from the jaws of 
 sundry animals. We know, for example, that with ourselves, 
 if we desire to crack a walnut or a filbert in our teeth, we 
 always put it as far back as possible, so as to make the leverage 
 as powerful as possible. No one would ever dream of crack- 
 ing a nut with his front teeth, an act which would be very
 
 NATURES TEACHINGS. 
 
 much like that of trying to break a piece of coal by pinching 
 it with the tongs. 
 
 The left-hand figure of the illustration represents part of the 
 jaws of the Wolf-fish, or Sea-wolf, as it is sometimes called, 
 and a very wonderful crushing machine it is. The Sea-wolf 
 (Anarrhicas lupus), sometimes called the Sea-cat, or Swine- 
 fish, is tolerably common on our coasts, and, as it sometimes 
 attains a length of seven feet, and is proportionately stout and 
 muscular, the power of its bite may be estimated. The fish in 
 question feeds chiefly on Crustacea and hard-shelled molluscs, 
 and is therefore furnished with an apparatus which can crush 
 their shells. Extremes meet. The Sea-anemones, which are 
 mere films of animal matter, and can be torn in pieces with 
 the finger and thumb, can seize, swallow, and digest a crab or 
 an oyster in spite of the thick and strong shells in which they 
 are enclosed. So can the Sea-wolf, and fishes of a similar 
 character. But nothing intermediate can touch them, and it 
 is curious to reflect that such opposite means should produce a 
 similar effect. 
 
 On reference to the illustration, the reader will see how 
 exact is the parallel between the Nut-crackers and the Sea- 
 wolf's jaws, both being worked on the same principle, and 
 both being furnished with a series of projecting points, which 
 are used for the purpose of preventing the escape of the object 
 which is to be crushed. The terrible grasping power of the 
 crocodile, the dolphin, and other predacious creatures can be 
 explained on the same principle. 
 
 THE ROLLING-MILL. 
 
 WE now come to another variation of the Crushing Machine, 
 i.e. that in which the motion is constant, and not intermittent, 
 as is the case with those machines which have just been 
 mentioned. 
 
 Perhaps some of my readers may have visited those great 
 iron-works in which huge masses of iron are rolled into plates 
 of greater or less thickness, or are cut up into strips as easily 
 as if they were butter. 
 
 The mechanism is in its principle simple enough. The 
 cylindrical rollers are placed nearly in contact, and forced
 
 THE ROLLING-MILL. 
 
 323 
 
 towards each other by mechanical means, such as levers, screws, 
 or springs, or all three combined. These cylinders revolve in 
 opposite directions, and, 'if any object be placed between them, 
 they draw it through them, and present it on the other side in 
 a flattened condition. 
 
 Many years ago, one of my schoolfellows, who had been 
 brought up entirely under the care of some maiden ladies, 
 was visiting a workshop, and must needs put his finger between 
 two revolving rollers. Of course the hand was drawn between 
 them, and simply squeezed flat. The machine was instantly 
 stopped, and the hand extricated ; and the strange thing was, 
 that the crushed and shapeless hand afterwards recovered its full 
 
 JAWS OF SKATE. 
 
 CKUSHING-MILL AND EOLLEB. 
 
 power, though not its shape, and was able to touch the keys of 
 the piano. 
 
 The whole process of the Rolling-mill is singularly inter- 
 esting, whether it be used for large or small objects. 
 
 Supposing that the grooved rollers of the illustration were 
 cut across so as to present a number of points, it is evident 
 that anything which got between them would be bitten to 
 pieces, each piece being of a tolerably uniform shape. 
 
 This plan is now adopted in the granulation of gunpowder. 
 After the future powder has emerged from the hydraulic 
 press in the form called "press-cake," it was formerly broken 
 to bits with wooden or copper mallets, and then placed in a 
 very peculiar kind of sieve. This was shaped like an ordinary 
 sieve, but the bottom was made of cowhide, pierced with 
 innumerable holes. A round pebble was placed in the 8?eve, 
 and, when the latter was violently shaken backwards and for- 
 
 Y 2
 
 324 NATURE'S TEACHINGS. 
 
 wards, the powder was driven through the holes by the pressure 
 of the stone, and was afterwards separated into its various 
 degrees of fineness. 
 
 I have only twice seen this process, and confess to have been 
 in a very nervous state on both occasions. The sieve is 
 whirled about with enormous velocity, and the pebble flies 
 round as if it were a thing alive. Let but a broken needle or a 
 fragment of stone get into the sieve, or even let the stone itself 
 break asunder, and there will be an instantaneous explosion, 
 which will hurl the house, the machinery, and the workmen 
 into unknown regions. 
 
 Now, however, the mode of granulating powder is radically 
 altered. There is a series of double cylinders, such as shown in 
 the illustration, and each of them has the ridges cut into teeth 
 in regular order. Thus the first set of rollers or cylinders 
 merely bites the press-cake into convenient pieces, though 
 seldom of the same weight. 
 
 The press-cake, thus bitten to pieces, is passed through a 
 series of cylindrical sieves, each graduated with the utmost 
 accuracy, and being turned by means of machinery. Being 
 set on a slope, the powder runs by its own weight down them, 
 and all those particles which cannot pass through the meshes 
 are poured out untouched at the lower end. 
 
 The portions which are too large to pass the openings of the 
 first sieve are then handed onwards by means of a machine called 
 a " Jacob's Ladder," which consists of a series of little vessels or 
 buckets strung on a tape, and revolving over a couple of wheels. 
 The first set of buckets takes the coarsely bitten press-cake to 
 the second set of rollers, the teeth of which are comparatively 
 small. Thence it is passed over to a third set, and so forth, until 
 it is delivered in any quality of grain which may be required. 
 
 The modern Mangle, again, affords a good example of this 
 principle. The old obtrusive, costly, and cumbrous Mangle, 
 which was nothing more than a heavy box of stones upon 
 rollers, has given place to the modern system of duplex action 
 in rollers, and one of the old Mangles is not easily to be seen, 
 unless it be worked as a curiosity. In fact, it is nearly as obso- 
 lete as the spinning-wheel, which yet may be seen in some of our 
 country villages, where scarcely one per cent, of the population 
 has ever been in a town, and many of them, the women espe-
 
 THE GRINDSTONE. 325 
 
 cially, make it their boast that they have never been beyond 
 the outskirts of their village. 
 
 This clumsy machine is now replaced by the very simple 
 invention which has been in vogue for some years, and which 
 can not only release, but regulate, the pressure at any moment, 
 by means of springs, levers, and weights. This machine is, in 
 fact, exactly the same as that which is represented in the illus- 
 tration, except that the rollers are quite smooth. They can be 
 adjusted to almost any amount of pressure by levers and weights 
 which are attached to the upper roller, and, when the linen has 
 passed through them, it has undergone the double operation of 
 wringing and mangling. This disposition of the rollers has 
 long been anticipated in the jaws of the Skate which crush to 
 pieces the shells of the whelks, periwinkles, &c., on which the 
 creature feeds. 
 
 THE GRINDSTONE. 
 
 BEING on the subject of jaws and teeth as a mode of breaking 
 to pieces objects which are placed between them, we will take 
 those implements which grind to powder, or "triturate," instead 
 of breaking or flattening. 
 
 From the very earliest ages, and as soon as man had begun 
 to discover the " staff of life," the art of grinding naturally 
 assumed an ever-increasing importance. 
 
 The first and most primitive mode of grinding corn and 
 converting it into meal was that which was followed by Sarah, 
 when she welcomed her husband's guests, which we know, from 
 internal evidence, was followed by the uncivilised races who 
 formerly inhabited this island, and by many semi-savages of 
 the present day. 
 
 Nothing could be simpler than the machinery used, and 
 nothing could cause a greater waste of muscular power. Two 
 stones were employed, a large one upon which the grain was 
 placed, and a smaller which was held in the hands, and used 
 for grinding the corn to powder, just as the painters of the 
 last century used to grind their colours. The Kafirs of 
 Southern Africa use this simple mill, and so exactly do they 
 keep unconsciously to the customs of long-perished natives, 
 that if one of their mills were buried for a few years and dug 
 up again, it might be mistaken for one of the ancient "querns."
 
 326 
 
 NATURE S TEACHINGS. 
 
 As the stone held in the hand was rounded, it naturally wore a 
 rounded hollow in the lower stone, and this made the process 
 of trituration easier. Perhaps some of my readers may have 
 noticed that when a chemist makes up a prescription, and is 
 obliged to reduce one of the ingredients to powder, he always 
 does so by rubbing, and not by pounding, as is generally believed. 
 He works the pestle round and round the mortar with a kind 
 of twisting motion, and thus obtains a powder much too fine to 
 have been produced by any amount of pounding. 
 
 The labour of this operation is necessarily very severe, and 
 therefore the Kafir of the present day, as did his predecessors 
 
 TOOTH OP ELEHIAXJ 
 
 GBIXDS^OXE. 
 
 of the long-lost races, declines to do it himself, but hands it 
 over to the women. In Palestine, as in other parts of the 
 world, a simple mill has been invented, which takes away 
 much of the labour, and, above all, releases the grinder from 
 the obligation of leaning with her fall weight upon the upper 
 stone. In this mill the stones are similar. The upper is 
 moved backwards and forwards round a pivot, and the grain is 
 passed between them by means of a conical aperture in the upper 
 stone, which answers the purpose of our "hopper." 
 
 In order to work this mill, two women are required, sitting 
 opposite each other, with the mill between them, holding the 
 same handle, and assisting each other in turning the stone 
 backwards and forwards. No one who has not seen this 
 operation can fully appreciate the force of the saying that 
 " two women shall be grinding at the mill ; the one shall be 
 taken, and the other left."
 
 GRINDING TEETH. 327 
 
 It is worthy of remark that, even at the present day, the 
 custom of grinding corn is carried out in Palestine as it was so 
 many centuries ago, and that it is repeated in Southern Africa 
 among the Kafir tribes. In both parts of the earth the first 
 sound of early morning is caused by the millstones of the 
 grinding women, and the amount and duration of the noise 
 afford a sure test of prosperity. Cessation of the millstones 
 signifies adversity and a thin population, as has been said by a 
 writer who lived not very far from three thousand years ago. 
 Speaking of tribulation, he mentions that " the grinders cease 
 because they be few, and that the doors shall be shut in the 
 streets when the sound of the grinding is low." 
 
 After awhile improvements were gradually introduced into 
 the business of grinding, not the least of which was covering 
 its surface with ridges, instead of leaving it entirely smooth, as 
 it had been formerly. Millers of the present time know the 
 value of these ridges, and the additional grinding power which 
 this " facing " gives to a stone. One of these stones is repre- 
 sented in the illustration, so as to show the system on which 
 the ridges and grooves are constructed. 
 
 Now, passing from Art to Nature, we find that the whole 
 system of the millstone, its movement and its ridged sur- 
 face, existed in the times when man had not yet come upon 
 earth. 
 
 The reader is probably aware that among the tooth-bearing 
 animals there are three types of teeth. First come the incisors, 
 or cutting teeth, which occupy the front of the jaw, and find 
 their fullest development in the rodent animals, such as the 
 beaver, the squirrel, the rabbit, and the rat. Next them 
 come the canine or piercing teeth, which are so highly de- 
 veloped in all the cat tribe. Lastly, there are the molar or 
 masticating teeth, so called from a Latin word signifying a 
 millstone, because their office is to grind food. 
 
 As it is with these last that we have now to treat, we will 
 say nothing about the others. 
 
 The molar teeth find their greatest development in the 
 Elephant, the structure of whose molars is exactly like that of 
 our modern millstones. There is certainly one very great 
 difference. When the surface of a millstone is rubbed away,
 
 328 NATURE'S TEACHINGS. 
 
 the stone must be re-faced, and sooner or later is worn out 
 altogether, and must be replaced with a new one. This, how- 
 ever, is not the case with the Elephant's molar teeth, which 
 not only keep their facing perfectly sharp, but have the faculty 
 of renewing themselves as fast as they are worn away. 
 
 How these important objects are attained we shall now see. 
 
 If the reader will refer to the upper left-hand figure of the 
 illustration, he will see that its surface is for the most part 
 round, with irregularly oval figures, close and thick at one 
 end, and almost disappearing at the other. These are the 
 "facings" of the Elephant's tooth, and they are formed as 
 follows : 
 
 The tooth, which is of enormous size, is not solid, but is 
 composed of a number of plates laid side by side, like a pack of 
 cards when set on their edge. Each of these plates is com- 
 posed of a hard external layer of enamel, and an internal 
 layer of comparatively soft bony matter. A slice of badly 
 made toast affords a familiar parallel, the half-charred outside 
 representing the enamel, and the soft, sodden interior being 
 analogous to the bony matter. In order to show the arrange- 
 ment of these plates, a side view of part of the tooth is given 
 on the same illustration. Sometimes, when the teeth of fossil 
 elephants are discovered, these plates all fall asunder, the 
 material which connected them having been dissolved away in 
 the earth. 
 
 When, however, we look upon the upper surface of a recent 
 tooth, we see it present the appearance which is shown in the 
 illustration. The elongated oval marks are the edges of the 
 hard enamel plates, while the spaces between them are filled 
 with the soft bony matter. It will be evident, then, that if two 
 teeth such as these be in opposite jaws, and perform the task 
 ^)f grinding food, their surface will always be well " faced." 
 Owing to the different hardness and density of the enamel and 
 bony substance, the latter will wear away with comparative 
 rapidity, leaving the former to project slightly, and thus to 
 preserve the facing of the natural mill. 
 
 This is, indeed, but a modification of the beautiful animal 
 mechanism which keeps the teeth of a rodent animal always 
 sharp, and always bevelled off at the proper angle. If we 
 could invent some plan whereby, in our millstones, we could
 
 ATMOSPHERIC PRESSURE. 329 
 
 make the facing of much harder material than the stone, we 
 should make an advance in the miller's art that would render 
 the millstones of the future as far superior to those of the 
 present as are our present millstones to the hand " quern " of 
 the Kafir women. 
 
 Yet another improvement has to be made. Would it be 
 possible to construct a millstone which should not only retain 
 its facing, but possess the power of renewing itself in propor- 
 tion as it is worn out? This property is found in the Elephant's 
 tooth, and the illustration will give a tolerably good idea of 
 the simple and beautiful mechanism by which it is brought 
 into operation. 
 
 The tooth, instead of being one solid mass, consists, as I have 
 already stated, of a series of plates set side by side. These 
 plates are so constructed that they are more worn away in 
 front than behind. In proportion as they are worn, a new tooth 
 is built up behind the old one, and gradually pushes off the old 
 one. Now, if we could only construct millstones with such 
 properties, we should possess an absolutely perfect instrument. 
 
 PRESSURE OF ATMOSPHERE. 
 
 THERE are many useful inventions which depend on the 
 weight of the atmosphere and the creation of a more or less 
 perfect vacuum. There is, for example, the common Pump, 
 which raises water simply by the action of the atmosphere. A 
 pipe passes into the water, and in that pipe an air-tight piston 
 is inserted. When the piston is drawn upwards a vacuum is 
 formed, and the water is at once forced into it by the pressure 
 of the atmosphere. 
 
 Then there is the graceful and useful Napier Coffee-making 
 Machine, consisting of a glass globe, and vase of the same 
 material. 
 
 Coffee and boiling water are put into the vase, and some hot 
 water into the globe. The two are then connected with the 
 tube, and under the globe is placed a spirit-lamp. Presently 
 the water in the globe boils, expelling the air and filling the 
 globe with steam. The lamp is then removed, and the steam 
 in the globe is condensed, leaving a vacuum. The pressure of 
 the atmosphere then comes to bear upon the coffee in the vase,
 
 330 NATURE'S TEACHINGS. 
 
 which is forced through the tube into the globe, producing 
 beautifully clear and well-flavoured coffee. 
 
 SURGERY employs the weight of the atmosphere in the 
 operation called " Cupping," now rarely employed, but for- 
 merly in such constant use that scarcely any man who had 
 attained middle age had not undergone it. The operation was 
 intended for the purpose of removing the blood from some 
 definite spot. Persons, for example, who appeared to have a 
 tendency to apoplexy were regularly cupped between the 
 shoulders twice a year, i.e. in the spring and autumn. 
 
 The mode of performing the operation is as follows : A 
 vase-shaped glass vessel called a cupping- glass is placed close 
 to the skin. The flame of a spirit-lamp is then introduced for 
 a moment in the glass so as to expel the air, and the glass 
 is rapidly placed with its mouth downwards on the skin. 
 If this be done with sufficient rapidity, the partial vacuum 
 in the cupping-glass causes it to adhere to the skin, which is 
 forced into it. by atmospheric pressure, as shown in the illustra- 
 tion. The blood is, of course, drawn towards the surface by the 
 same means. 
 
 The glass is then quickly removed, and a little brass instru- 
 ment applied, which, at the touching of a spring, sends out a 
 number of small lancet-blades so formed as to make very 
 slight cuts. The glass is again applied, and rapidly becomes 
 filled with blood from the cuts, the air having forced it in 
 exactly as it forces the coffee in Napier's machine. 
 
 IN the upper right-hand corner of the illustration is shown 
 the Pneumatic Peg, a comparatively recent invention, and 
 useful in cases where much strength is not required. The base 
 of the peg is fitted with a sort of cup made of india-rubber. 
 When this base is pressed against a smooth and flat surface, 
 such as a pane of glass, the air is forced out of the cup, and a 
 vacuum formed. The pressure of the atmosphere then causes 
 the cup to adhere to the glass with sufficient force to enable 
 objects to be suspended from it. 
 
 The boy's well-known toy, the Sucker, is made on exactly the 
 same principle. A piece of leather, generally circular, though 
 the shape is not of much consequence, has a hole bored through
 
 SUCKERS. 
 
 331 
 
 its centre, so as to allow a string to be attached. The leather 
 is then soaked in water until it is quite soft. If it be firmly 
 pressed on any smooth object, such as a stone, the air is 
 forced from under it, and it becomes capable of sustaining a 
 weight in proportion to its dimensions. As the air has a 
 pressure of about fifteen pounds on every square inch, it is easy 
 
 SUCKERS OF CUTTLE. 
 
 LIMPET. 
 
 STAB-FISH. 
 
 SUCKING-FISH. 
 
 FOOT OF GECKO. 
 
 LAMPEHX. 
 
 CUPPING-GLASS. 
 
 PNEUMATIC PEG. 
 
 8UCKEB. 
 
 MAGDEBUBO HEMISPHERES. 
 
 to calculate the weight which it will uphold, a margin being 
 left for imperfection of vacuum. 
 
 The lower figure represents the instrument called the 
 Magdeburg Hemispheres, which are made for the purpose 
 of showing the enormous power of air-pressure. They are 
 two hollowed hemispheres, having their edges very accurately 
 ground together. When used, a little lard is rubbed on the 
 edges in order to insure their exact fit, and they are then
 
 332 NATURE*S TEACHINGS. 
 
 pressed tightly together. The air is removed by means of the 
 common exhausting syringe, and it is found that the two 
 adhere together with such force that two strong men cannot 
 pull them asunder. But, if the tap be turned, and air 
 admitted, they come apart without the least difficulty. 
 
 Similarly, if two plates of glass or metal be ground to 
 exactly plane surfaces, and pressed together, they adhere 
 nearly as strongly as if they were one solid piece. 
 
 WE will now turn from Art to Nature, and examine some 
 natural producers of vacuum. 
 
 One of the most celebrated is that series of suckers whicli 
 may be found upon the arms of the various Cuttles. At the 
 upper part of the illustration a figure is given of part of an 
 arm, on which are four suckers. When the animal wishes to 
 attach itself to any object, it presses the disc of the sucker 
 against it, and simultaneously withdraws the centre, exactly as 
 the boy does with his toy sucker. And, as each arm contains 
 a great number of suckers, it is evident that the holding power 
 must be very great. Indeed, on one occasion when a com- 
 paratively small specimen had fastened on a man's arm, he 
 could not remove it, but was obliged to have it cut away piece- 
 meal by an assistant. 
 
 The common Water-beetle has similar suckers upon its first 
 pair of feet, and can adhere to smooth surfaces with great 
 tenacity. 
 
 ON the left of the cuttle-arm is the common Limpet, shown 
 as it appears when adhering to the rocks. Every visitor to 
 the seaside who has attempted to remove the Limpets may 
 remember how difficult it is to stir them when they have once 
 taken their hold. If they can be taken by surprise, they come 
 away with a touch ; but if they become alarmed, they press the 
 edges of the foot firmly against the rock, withdraw the centre, 
 and thus create the necessary vacuum. 
 
 NEXT follows a Star-fish, shown as it appears when in the 
 act of walking, or rather, gliding along. 
 
 This movement is obtained by the use of a vast number of 
 long suckers, exactly resembling the pneumatic peg, except
 
 THF. SUCKING-FISH. 333 
 
 that they are flexible, and can be curved in any direction. It 
 is really beautiful to see the manner in which a Star-fish will 
 glide along by means of its suckers, its arms accommodating 
 themselves to the irregularities of the ground, and its multi- 
 tudinous suckers protruded and withdrawn with a never- 
 ceasing movement. 
 
 And, as the Star- fish is apparently blind, not having any 
 organs which can even be conjectured to serve the purpose of 
 vision, this mode of directing its course is not easily under- 
 stood. Yet, blind though it may be, it guides itself with as 
 much accuracy as if it possessed eyes, and evidently does so 
 with a definite purpose, using its suckers with as much decision 
 as a centipede uses its legs. 
 
 These suckers can be seen very well by placing a Star -fish in 
 a shallow vessel of sea-water, and laying it on its back. The 
 suckers immediately protrude themselves from their little 
 apertures, and the arms slowly curve themselves so as to find 
 something to which the suckers can adhere. Presently one or 
 two of the suckers will take hold of the bottom of the vessel. 
 Others soon follow, and in a very short time the Star- fish is on 
 its legs, if we may so call them, and is quietly gliding on its 
 way. 
 
 BELOW the Star-fish is seen the celebrated Sucking-fish 
 (Echeneis remora) about which so many strange tales have been 
 told, and which is possessed of a structure remarkable enough 
 to need no aid from invention. The dorsal fin of this fish is 
 modified in a most singular manner. The spines of which it is 
 so largely composed are metamorphosed into flattened plates 
 very much resembling the laths of a Venetian blind, and form 
 an instrument of suction identical in principle, though not in 
 form, with those which have already been described. When 
 the sucker is pressed against a smooth surface, a vacuum is 
 formed, and the fish in consequence adheres firmly to the 
 object. 
 
 The fact has been known for centuries, though it has only 
 been lately discovered, that the sucker was not a separate 
 apparatus, but merely one of the fins modified in a simple 
 though effective manner. Indeed, any one who has some 
 slight notion of the structure of a fin can easily see, by looking
 
 334 NATURE'S TEACHINGS. 
 
 at the Sucking-fish, from above, that the apparatus is nothing 
 more than the dorsal fin laid flat. 
 
 I may mention here that the name of Echeneis is taken from 
 two words signifying " ship-holder." It was given to the fish on 
 account of a curious notion which was fully believed until quite 
 modern times, that the Sucking-fish had the power of attaching 
 itself to ships, and holding them so firmly that they could not 
 proceed in spite of sails and oars. The word Echeneis is used 
 by Aristotle in his " History of Animals." The specific name 
 remora, or " delay," is Latin, and is given to the fish for the 
 same reason. 
 
 The little Gobies, which are so plentiful along our coasts, 
 have the ventral fins formed into a sucker, with which they can 
 cling firmly to any object, such as a leaf of seaweed or a 
 smooth rock or stone. A similar modification of the ventral 
 fins is also found in the beautifully coloured Lump-fish, or 
 Lump-sucker, sometimes called the Cock-paidle. One of these 
 fishes, when placed in a bucket of water, adhered so strongly to 
 the bottom, that, when lifted by the tail, it bore the whole 
 weight of the pail and water. 
 
 JUST below the Sucking-fish is drawn a foot of the curious 
 little lizard, the Gecko, so called from its peculiar cry. It is 
 common in the West Indies, and haunts houses, traversing 
 their walls just as flies run up panes of glass. It is enabled to 
 perform this movement by means of the structure of the feet. 
 As the reader may see by reference to the illustration, the toes 
 are greatly widened and flattened. If the lower surface be 
 examined, it will be found to be furnished with a number of 
 plates very much resembling those of the sucking-fish, and 
 performing the same office. 
 
 So rapid is the operation of these plates, that the animal can 
 even leap upon a perpendicular flat surface, and stick there. 
 Perhaps the reader may remember that the beautiful Tree- 
 frogs, which cling so tightly to leaves, are furnished with 
 suckers on their toes, whereby they can hold on even to an 
 upright pane of glass. In fact, the smooth surface of the glass 
 seems to please them, and when they adhere to it they give an 
 excellent opportunity of examining the structure of the feet 
 with a magnifying-glass.
 
 THE LAMPERN AND THE LEECH. 335 
 
 Another example of the pressure of the atmosphere has 
 been slightly mentioned, when treating of the ball-and-socket 
 joint. This is the joint by which the thigh-bone is attached to 
 the hip. As the rounded head of the thigh-bone fits exactly 
 into the cavity of the hip, and is, moreover, well lubricated 
 with the animal oil called synovia, no air can obtain admission 
 between the two. Consequently, they are held together so 
 firmly by the pressure of the atmosphere, that they retain 
 their places even after the whole of the muscular attachments 
 have been removed. Not without very great force can the 
 thigh-bone be dislodged from the shallow socket in which it 
 lies ; but, if a hole be bored so as to admit the air, it comes out 
 at once. 
 
 Similarly, however firmly a limpet may cling to the rock, if 
 the finest needle were introduced so as to admit air, the creature 
 
 could not retain its hold for a moment. 
 
 
 
 THE last figure on the illustration represents the common 
 Lampern (Lampetra fluviatilis] . 
 
 The mouth of this little fish is formed on the principle of the 
 sucker, and very firmly it can adhere, as I can state from much 
 personal experience, Indeed, it is rather alarming, to those 
 who are unacquainted with the character of the fish, to have it 
 turn round and fasten upon the hand. However, it is quite 
 harmless, and those who are accustomed to them will have 
 half-a-dozen hanging on their hand at a time, and take no 
 notice of them. 
 
 ALREADY has it been mentioned that Surgery has pressed 
 into its service the weight of the atmosphere by means of cup- 
 ping. She also makes use of Nature in a similar manner by 
 employing the Leech for local and surface bleeding. 
 
 The mouth of the Medicinal Leech forms an exact parallel with 
 the cupping-glass and lancets, only that it is very far superior 
 in its powers. To make the analogy perfect, the lancets ought 
 to be within the cupping-glass, and the latter ought to be able 
 to exhaust the air from itself, and to be attached to a reservoir 
 into which the blood could be passed. 
 
 I need hardly mention that the action of sucking as prac- 
 tised by the young of all mammalian beings, from man down-
 
 336 
 
 NATURE'S TEACHINGS. 
 
 wards, is due to the same principle. By the action of sucking 
 a partial vacuum is formed, and the pressure of the atmosphere 
 upon the breasts forces the milk into the mouth of the young. 
 
 "We might multiply examples ad infinitum, and we will there- 
 fore pass to another subject. 
 
 SEED-DRILLS. 
 
 AMONG the modern improvements in agriculture we may 
 reckon the invention of the Seed-drill as one of the most 
 important. By means of this invention, seed is greatly 
 
 JCHKEUMOS-FLY. 
 
 GRASSHOPPER. 
 
 SEED-DRILL. 
 
 economized, the supply can be regulated, and the sower knows 
 exactly where every grain of seed goes. There is no scatter- 
 ing, as in the wasteful broadcast plan, by which the seeds are 
 flung almost at random over the field, and may or may not fall 
 into the furrows. The Seed-drill, on the contrary, either stamps 
 holes or ploughs narrow furrows, measures the seed into 
 them, and in some machines replaces the earth. The 
 former kind of machine rather deserves the name of a dibble, 
 and was invented for the purpose of superseding the use of the 
 hand-dibble.
 
 NATURAL DIBBLES. 337 
 
 It is really a pitiful thing to see human beings endowed with 
 reason and aspirations performing such a task as dibbling by 
 hand, one going backwards with a dibble in each hand, and the 
 other following and putting seed into the holes. Yet the field 
 labourers have the greatest objection to the machine dibble, as, 
 indeed, they have to any sort of labour-saving machine, thinking 
 that it will lessen the demand for labour, and prevent them 
 from earning a livelihood. 
 
 I well remember how a country clergyman, pitying the hard 
 toil of the hand-dibblers, took occasion when he visited town to 
 purchase a machine dibble wherewith one man could set eight 
 rows of beans at once. It was a very simple affair, compre- 
 hensible even by the dull brain of a Wiltshire labourer. His 
 trouble was all in vain, for no one would use it, and there was 
 such a disturbance about it in the village, that for the sake of 
 peace its owner laid it up in a loft and abandoned its use. 
 There might be some semblance of reason in thinking that it 
 would deprive them of their field labour, but no cottager would 
 even use it in his own garden, though it was freely offered to 
 any one who wished to borrow it. 
 
 THESE machines have their parallels in Nature, two of which 
 are represented in the illustration. 
 
 The lower left-hand figure represents the female Grasshopper 
 depositing her eggs. She is furnished with a sharply pointed 
 ovipositor, composed of two blades. When she is about to lay 
 her eggs, she searches for a suitable piece of ground, where the 
 earth is tolerably soft, and with the closed ovipositor bores a 
 hole. She then separates the blades slightly, and an egg glides 
 between them into the ground, precisely as is done by the 
 machine dibble with its beans. When I first saw and used the 
 instrument, some twenty-five years ago, the parallel struck me 
 at once. 
 
 THE female of the familiar Daddy Long-legs (Tipula) acts 
 in a similar manner. She is furnished with an ovipositor too 
 short to be used like that of the grasshopper, and so she attains 
 her object in a rather different manner. Making use of her 
 long stilt-like legs, she sets herself nearly upright, with the 
 point of the ovipositor in the ground. She then twists herself
 
 338 NATURE'S TEACHINGS. 
 
 from side to side, just after the principle of the bradawl, and 
 so proceeds until she has made a hole large enough for her 
 purpose. The blades of the ovipositor are then separated, and 
 the egg placed in the hole, as has been described of the grass- 
 hopper. 
 
 THE upper figure represents one of the large Ichneumon-flies 
 depositing the egg in the grub of some wood- inhabiting larva. 
 How she bores the hole has already been described when treating 
 of Boring Tools, and the process need not again be discussed. 
 The principal point at present is, that after the hole is bored, an 
 egg caa pass between the blades of the ovipositor, though they 
 are but little thicker than human hairs. 
 
 One of the most extraordinary instances of this kind of ovi- 
 positor is found in an Ichneumon-fly brought from Bogota. The 
 body, from the head to the end of the tail, is not quite an inch 
 long, while the ovipositor is six inches and a half in length, and 
 scarcely thicker than that of the insect whose portrait is given 
 in the illustration. Nothing is as yet known of its habits, so 
 that the object of this wonderfully long ovipositor is a mystery. 
 But that it should be used like other ovipositors is evident 
 enough, and the chief wonder is, what are the mechanical means 
 whereby an egg can be propelled between blades so long and 
 slender. 
 
 There is a genus of Ichneumon -flies called Pelecinus. They 
 deposit their eggs in wood-boring larvaj, and we might imagine 
 that the ovipositor would be a long one. It is, however, ex- 
 tremely short, and the requisite length is obtained by the form 
 of the abdomen, the joints of which are so long and narrow that 
 they almost look as if they had passed through a wire-drawing 
 machine, the length of the head and throat being three-eighths 
 of an inch, and that of the abdomen an inch and a half. This 
 long abdomen belongs only to the female, that of the male 
 being short and club-shaped.
 
 USEFUL AETS. 
 
 CHAPTER III. 
 
 CLOTH-DRESSING. BRUSHES AND COMBS. BUTTONS, HOOKS 
 AND EYES, AND CLASP. 
 
 The Teazle and its Structure. Tts Use in raising the " Nap" on Cloth. Its Value 
 in Commerce. Artificial Teazles. The modern Cloth-dressing Machine. 
 The Brush an Article of Luxury. Definition of the Brush, and its various 
 Uses. Brushes in Nature. The Foot of the Fly and the, Tail-brush of the 
 Glow-worm Larva. Mode in which they are used. The Comb. Varieties 
 of the Comb as made in different Countries. Combs in Nature. Foot of the 
 Spider and its Uses. Beak of the Toucan. Comb of the Scorpion. Buttons, 
 Hooks and Eyes. Use of the Button. The Egyptian Garment. The 
 Buckle and the Shoe-tie. The Clasp. Wing-hooks of various Insects. 
 The Saddle-back Oyster. 
 
 CLOTH -DRESSING MACHINE. 
 
 IN former days, when so much was done by hand that is now 
 done by machinery, the thistle called the Teazle (Dipsacus 
 fullonum) was of great value in British commerce, being used 
 by countless thousands in the manufacture of broadcloth. 
 
 "When the woollen threads are woven so as to form the fabric 
 of the cloth, there is no nap upon them, this having to be pro- 
 duced by a subsequent process. The plan of former days was, 
 to procure a quantity of the seed-vessels of the Teazle, and dry 
 them. They were then fastened to an instrument something 
 like a wooden battledore, and swept over the surface of the cloth. 
 By degrees the delicate booklets which terminate the many 
 scales of the seed-vessel tore up the fibres of the cloth, and pro- 
 duced the desired nap without impairing the strength of the 
 thread. When this nap is worn off, the threads are again 
 visible, producing the effect called " threadbare." 
 
 As the art of weaving continued to progress, the demand for 
 Teazles increased in due proportion, and vast quantities were? 
 
 z 2
 
 340 
 
 NATURE S TEACHINGS. 
 
 imported from abroad. Instead of being used by hand, they 
 were then fastened to the circumference of wooden wheels as 
 broad as the width of the cloth, and made to revolve rapidly, 
 while the cloth was pressed against them. 
 
 For many years attempts had been made to construct artificial 
 Teazles which would not wear out so rapidly as did the dry seed- 
 vessels, but nothing could be constructed that was not too stiff 
 or too strong, and which did not injure the threads while pro- 
 ducing the nap. At last, however, this difficult problem has 
 been solved, and the Teazle is no longer an important article of 
 
 ttr 
 
 CLOTH-DRESSING. 
 
 commerce, its place being supplied by delicately made cards of 
 the finest and most elastic wire. 
 
 In the illustration a head of Teazle is given on the left hand, 
 and on the right is seen the mode in which the wire cards are 
 placed in the machine, and the cloth drawn over them so as to 
 produce the required nap. 
 
 BRUSHES. 
 
 IT is worthy of notice that there are many articles of com- 
 parative luxury which could not be used until man had 
 attained some degree of civilisation. Among these we may 
 class the Brush and the Comb, no true savage ever troubling 
 himself about either article. The Brush, indeed, belongs to a 
 much more advanced stage of civilisation than the Comb, for 
 whereas we find combs, however rude they may be, used in 
 semi-savage, or rather, barbarian countries, the Brush is, as far 
 as I know, an adjunct of a high state of civilisation.
 
 BRUSHES. 341 
 
 Brushes may be defined to be instruments formed of fibres 
 set more or less parallel to each other. The vast variety of 
 brushes used in different parts of Europe is indicative of the 
 civilisation of the nations who use them. Take, for example, 
 the brushes used in household management, such as the hearth- 
 brush, the housemaid's brush, the Turk's-head brush, the 
 crumb-brush, the stair-brush, the carpet-brush, the dusting 
 brush, and many others. 
 
 Then we have those which are applied to our garments, such 
 as the ordinary clothes-brush, the velvet-backed hat-brush, and 
 the three kinds of boot-brushes. 
 
 In architecture, again, we should be very badly off without 
 the painting-brushes, the whitewasher's brush, and the paper- 
 hanger's brush ; not to mention the exceeding variety of 
 brushes used by artists both in oil and water colours. 
 
 As to brushes applied to our persons, we have an infinite 
 number of them. There is, of course, the hair-brush, without 
 a pair of which, one for each hand, no one with a respectable 
 head of hair could be expected to be happy. 
 
 We may add to this the revolving brush worked by 
 machinery, which is to be found in the rooms of any respect- 
 able hairdresser, and which is a sort of an apotheosis of the 
 Hair-brush, especially when it is worked, as in some places, by 
 the electrical engine. 
 
 Then there is the shaving-brush, once an absolutely necessary 
 article in a gentleman's dressing-case, and above all requisite if 
 the owner should happen to be a clergyman. Nowadays, 
 shaving is rapidly decreasing, and of all the professions, those 
 who are most largely bearded, both in number of beard- wearers 
 and dimensions of the beard, are to be found among the clergy. 
 
 Then there are any number of tooth-brushes for the interior 
 of the mouth, and of flesh-brushes, with or without handles, for 
 the service of the bath. There are even gardeners' brushes, for 
 the purpose of clearing the plants of the aphides, or green- 
 blight, as these insects are popularly called by gardeners. So 
 it will be seen that absurd as the proposition may appear at 
 first sight we may really accept the use of the brush as a safe 
 test of the progress of civilisation. 
 
 WE will now glance at the illustrations of this subject.
 
 342 
 
 NATURE S TEACHINGS. 
 
 On the right hand is depicted the once honoured Shaving- 
 brush, the terror of all stiff- bearded men on frosty mornings, 
 and yet clung to with a strange inconsistency. Many years 
 ago a military member of the House of Commons was sensible 
 enough to wear nis beard, and was, in consequence, the butt for 
 interminable jokes. At the present time, if the House were 
 counted, a great majority of the younger, and not a few of the 
 older, members will be found to wear either the beard or 
 moustache, or both. 
 
 Perhaps some of my readers may object that many nations in 
 a state of very partial civilisation are accustomed to shaving. 
 So they are, but they do not use the shaving-brush. Most of 
 
 FOOT OF FLY. 
 
 BRUSH OF OLOW- 
 WOBM LA1.VA. 
 
 HAIR-BBtJBHBS. 
 
 SHAVING- BRUSH. 
 
 them content themselves with pulling out the hairs by the 
 roots, while others merely saturate the hair with hot water, and 
 so need no brush. 
 
 Next to the shaving-brush is drawn a pair of ordinary Hair- 
 brushes, such as have been mentioned. 
 
 PASSING to the left, we find an object which bears a curious 
 resemblance to the shaving-brush. This is an apparatus 
 belonging to the larva or grub of the Glow-worm. This 
 creature feeds upon snails, and, in consequence, gets itself 
 covered with the tenacious slime. In order to enable it to rid 
 itself of this inconvenience, the larva is furnished near the end 
 of its tail with the curious apparatus which is here shown. It 
 consists of some seven or eight soft white radii, arranged so as 
 to produce a brush-like outline, and being capable of extension 
 or withdrawal at will.
 
 COMBS. 343 
 
 It had long been known that this "houppe nerveuse," as it is 
 called, was employed as an assistant in locomotion ; but until 
 comparatively late years I believe about 1826 no one 
 seemed to be aware that it was used as a brush. Its func- 
 tions as a brush may be compared with the somewhat similar 
 offices fulfilled by the pincers of the Earwig, as mentioned 
 on page 259. 
 
 Next to the brush of the glow-worm larva is shown one of the 
 fore-feet of the ordinary house-fly, much magnified. Passing, 
 as irrelevant to the present subject, the use of the feet as organs 
 of locomotion, we may take them as being used for the purpose 
 of cleansing the body of the insect. 
 
 I suppose that none of my readers has been sufficiently 
 inobservant not to have noticed the way in which a fly cleanses 
 itself, behaving almost exactly like a cat under similar circum- 
 stances. The fore-feet are repeatedly passed over the head, 
 which is bowed down to meet them, while a similar office is 
 performed for the rest of the body by the hind-legs. The feet 
 are then rubbed against each other, so as to free them from all 
 accumulations, just as the housemaid cleanses the hair-brush 
 with the comb before washing it. So mechanical is this 
 process, that a fly has been known to go through it even after it 
 had been deprived of its head. 
 
 The reader will see, on reference to the illustration, that the 
 two sharp and curved claws are capable of answering the pur- 
 pose of combs, and, indeed, are so employed. 
 
 COMBS. 
 
 WE will now proceed to the COMB, and see how Art has 
 been anticipated by Nature. 
 
 As long as human beings possess hair upon their heads, 
 whether it be the short, frizzed, woolly pile of the negro, the 
 thick, coarse crop of the Fijian, the coarse, straight hair of the 
 Mongolian, or the long and fine hair of the Georgian races, 
 they must, as soon as they attempt any kind of civilisation, 
 form some instruments by which the hair can be dressed. The 
 simplest machine for this purpose is the Comb, and I possess 
 many varieties of this article, suitable to the different races for 
 whom it was made.
 
 844 
 
 NATURE S TEACHINGS. 
 
 Putting aside the ordinary Combs of our European civilisa- 
 tion, such as are given in the illustration, there are many 
 others which are modified according to the use which they have 
 to fulfil. 
 
 The simplest is the Comb of the celebrated Amazon regi- 
 ment of Dahomey. This is nothing but a slight skewer of 
 ivory, some ten inches in length, and amply suificient for 
 arranging the short woolly lumps which do duty for hair on 
 the head of a true negro. One of these very primitive combs 
 is in my collection, together with an undress costume of the 
 Ama/on in question, and both being very much suited to each 
 
 FOOT OP SPIDKB. 
 BEAK OF TOUCAN. 
 
 other. The comb being a simple skewer, the dress is only a 
 few thongs of leather, but they are both equal to the require- 
 ments of their wearers. 
 
 As much time would be lost in combing the hair with a 
 single skewer, especially when that hair belonged to any but 
 the pure negro races, a simple but obvious improvement was 
 introduced. A number of skewers were lashed together side 
 by side, with their ends a little diverging, and thus was formed 
 the germ of our present Combs. 
 
 As to the varieties of the Comb, they are simply endless ; 
 and whether they are intended, in the form of the Currycomb, 
 to smooth the harsh coat of a horse, or, as a small-tooth Comb, 
 to search the hair of the young, they are all based on one 
 principle. 
 
 It is really curious to see how often two men, who cannot
 
 FOOT OF THE SPIDER. 845 
 
 possibly have seen each other, will hit upon the same idea, not 
 only simultaneously, but often in the very same words. So it 
 is with regard to the Comb. In no two parts of the world can 
 the natives be more opposed to each other than is the case with 
 Fiji and Western Africa ; yet I possess specimens of combs 
 from both countries, made on the same principles, and so 
 exactly in the same manner, that, except for the coarseness 
 of the African Comb, it would be almost impossible to distin- 
 guish between them. There is but a slight difference in the 
 size and shape of the two combs, and yet nothing can be more 
 distinct than the characters of the two nations. 
 
 I have also a Japanese Comb of the most ingenious con- 
 struction. It is made of wood, and cut exactly like our double 
 ivory small-tooth comb ; but it is furnished with a curious 
 kind of handle, consisting of a flat piece of wood with a deep 
 longitudinal slit, into which either side of the comb fits ; and 
 so beautifully is it made, that when it is fitted upon either 
 side of the comb it looks as if handle and comb had been cut 
 out of the same piece of wood. 
 
 The Fijian Combs are much after the same fashion as those 
 of Western Africa, except that, with the artistic nature of 
 their kind, the Fijians, instead of merely lashing together the 
 numerous spikes of which the comb is made, employ a variety 
 of patterns, and seem to luxuriate in the exuberance of artistic 
 spirit which can make hundreds of combs, and no two of them 
 alike. 
 
 ON the left hand of the illustration are two examples of 
 Natural Combs which are well worthy of notice. The upper 
 one is a foot of the common Garden Spider (Epeira diadem a], 
 which has been several times mentioned in this work in con- 
 nection with different subjects. 
 
 Every one who has watched the life of one of these creatures 
 must have noticed how often its hairy body becomes clogged 
 with little bits of its own web, and how dexterously it releases 
 itself from such encumbrances. The figure in the illustration 
 shows how this can be done, the strangely formed foot acting 
 at the same time the part of comb and brush. It will be seen 
 that the curved spikes of the claws act as a comb, while the 
 bristle-like hairs discharge the duty of a brush.
 
 346 NATURE'S TEACHINGS. 
 
 NOT only are these projections used as Combs, but as 
 appendages which insure the security of footing along the 
 lines of the web. The reader will easily remember that when 
 a Spider rushes along its web to secure its prey, it always runs 
 along one of the radiating lines, which have no viscid drops, 
 and that it never misses its hold. The latter point is secured 
 by the structure of its claws, which are so made that if one 
 projection misses the line, another is sure to fasten upon it. 
 Some years ago, while watching "Blondin" go through his 
 wonderful performances, I was especially struck with the 
 pattern on which he had constructed the stilts upon which he 
 traversed the rope. They were made in the most exact imi- 
 tation of the Spider's foot, and though it is not probable that 
 he borrowed them from that object, the resemblance was so 
 close that he might readily have done so. 
 
 BELOW the spider's foot is given the head of a Toucan, one 
 of those beautifully coloured and large-billed birds that inhabit 
 tropical America. These birds are very particular about their 
 plumage, and even when in captivity dress their feathers -with 
 the utmost care. When they do so, the saw-like notches of the 
 beak act the part of a comb, and the fibrils of the feathers are 
 by their action dressed parallel to each other, and give to the 
 whole bird its proper appearance of health. 
 
 I MAY here mention that there is one comb in Nature, the 
 use of which has never been clearly ascertained. This is the 
 remarkable organ found in the Scorpion, and simply known as 
 the " comb." There are two of them, one on each side of the 
 under surface. Their colour differs slightly according to the 
 species, but is generally a light yellow brown. The number of 
 teeth also differs extremely, for in the Hock Scorpion there 
 are only thirteen teeth, while in the Red Scorpion there are 
 twenty-eight. 
 
 BUTTONS, HOOKS AND EYES, AND CLASP. 
 
 HAVING now treated of brushes and combs as articles belong- 
 ing to the toilet, we will proceed to those which belong to 
 the dress rather than the person. It is a curious fact that, as
 
 BUTTONS AND CLASPS. 347 
 
 far as is known, buttons and hooks belong only to advanced 
 civilisation. The simplest garment is, of course, a cloth of 
 some material' wrapped round the waist, and, as we see in the 
 wonderful Egyptian paintings which have survived their 
 painters some three thousand years, the simple fold can retain 
 its grasp round the loins, even through the exertions of a long 
 day's work. 
 
 I was always at a loss, when looking at these drawings, to 
 understand how a single fold could retain so simple a garment 
 in its place, but when I made my first visit to the Hammam 
 Turkish Bath in Jermyn Street the mystery was at once solved. 
 The "check," as it is there called, is long enough to pass about 
 once and a half round the waist of an ordinary man. One 
 end of it is placed on the left side, so as to bring the lower 
 edge on a level with the knee. It is held by the left hand 
 until the right hand passes it round the waist. It is then turned 
 over in a broad single fold, and will remain in position for 
 hours, the left leg having free scope between the two ends, and 
 yet not being needlessly exposed. 
 
 Next to the simple fold comes the tie, which is in use all 
 over the world. The chief object of a good Tie is that it 
 should retain its hold as long as needed, be loosened with a 
 touch in necessity, and, as a matter of consequence, should 
 never "jam." 
 
 Still, even the best of ties are liable to objection. I once 
 heard an argument on the subject of ties and buckles with 
 regard to shoes. The speakers were both Derbyshire men, 
 and their phraseology was somewhat obscure. However, both 
 stuck to his own principles, one saying that "when a shee-uew 
 is boo-oo-oockled, it's boo-oo-ookled ; " and the other assert- 
 ing, in equally strong terms, that " when it's tee-ee-eed, it's 
 tee-ee-eea. 
 
 The buckle was here asserting its supremacy in civilisation 
 over the tie, and was palpably right. Any one, so rose the 
 argument, can tie two strings together, but the structure of the 
 buckle is too complicated to be understood, much less invented, 
 by any uncivilised being. 
 
 NEXT come, in natural order, the Button and the Clasp, 
 each being identical in principle. In the case of the former
 
 343 
 
 NATURE S TEACHINGS. 
 
 the " eye " is placed over the button, while in the latter the 
 clasp or hook is passed through the eye. Several examples 
 of the Button and the Clasp are given on the right hand of 
 the illustration, and are too familiar to need description. 
 
 As to the corresponding articles in Nature, they are very 
 numerous. We will take, for example, the Saddle-back or 
 Crow Oyster of our own shores. It is a most remarkable 
 being. It deposits upon the object to which it adheres a sort 
 of button of shelly matter, and the lower valve, which is nearly 
 flat, has in it an aperture which is placed over the knob, just 
 
 WI\O-HOOKS OF INSECT. 
 SADDLE-BACK OYSTEE. 
 
 CLASPS AND BUTTON. 
 
 ns a button-hole goes over the button. As this arrangement 
 is confined to the lower valve, and cannot be seen unless the 
 upper valve be removed, the lower valve only is shown in the 
 illustration, as it appears when fastened to the side of a large 
 limpet. 
 
 OF the Hooks and Eyes in Nature I have only taken two 
 examples, though there are many others. 
 
 We all know the Bees, Wasps, Hornets, and other similar 
 insects, and that they possess four wings. I may here mention 
 that no insect which does not possess four transparent wings 
 is capable of stinging. 
 
 When the insect is at rest the four wings may be easily 
 distinguished, but when it is in flight they coalesce, so that 
 practically the insect has two wings instead of four. This 
 object is attained in the following way :
 
 WING-HOOKS OF INSECTS. 349 
 
 lower edge of the first pair of wings is turned over 
 in a rather stiff fold. The upper edge of the second pair of 
 wings has a row of small, but strong and elastic hooks. When, 
 the insect is about to fly, the hooks are hitched into the fold, 
 and so the wings are fastened together. These hooks are 
 shown in the illustration, and the reader will easily see how 
 effective they must be in their operation. An almost exactly 
 similar structure is found in the feathers of birds, and it is by 
 means of these tiny hooks that wings are enabled to present a 
 continuous, light, and elastic surface in the air.
 
 USEFUL ARTS. 
 
 CHAPTER IV. 
 
 THE STOPPER, OR CORK. THE FILTER. 
 
 Vessels and their Covers. Corks. Mode of bottling Wine. Conical Corks and 
 .Stoppers. Self- fitting Candles. Candle- fixers. The Vent-peg. The 
 Blow-guns and their Missiles. The Serpula and its Conical Stopper. The 
 Filter. The Bosjesman procuring Water. How to make a simple Filter. 
 The Earth as a Filter. The Sea-mouse, or Aphrodite, and its filtering Appa- 
 ratus. The Duck's Beak, and its beautiful Structure. The Jaw of the 
 Greenland Whale. Fork-grinder's Respirator. How Insects breathe. 
 Spiracles, and their general Structure. Spiracle of the Fly. Experiment 
 upon a Cockroach, and its Result. 
 
 THE STOPPER, OR CORK. 
 
 THIS object, as depicted in the illustration, is a product of 
 civilised life, though, as soon as a savage could make a 
 vessel, he seems to have made a Cover for it if it were of large 
 diameter, or a Stopper if the opening were small. Even the 
 very Bosjesman, who is quite unable to make a clay vessel, and 
 uses empty ostrich eggs by way of water-bottles, is yet 
 capable of making plugs with which he can stop up the 
 apertures. Then the Kafir, with his gourd vessels, whether 
 they be for water or snuff, makes a plug that fits tightly 
 enough to exclude the air, as well as to retain the contents. 
 
 The invention of glass bottles necessarily brought with it the 
 introduction of a new kind of plug, and a material for such a 
 plug was found in the bark of the cork-tree, a species of oak. 
 This bark possesses the capability of compression to a very 
 great extent, and, being highly elastic, it expands as soon as 
 the pressure is removed. 
 
 Thus, in bottling wine, the corks are always made much 
 too large to go into the mouths of the bottles. They are first
 
 CORKS AND STOPPERS. 351 
 
 dipped in a cup containing the same wine, and are then com- 
 pressed violently by amichine worked by a handle, and which, 
 being practically a powerful pair of nut-crackers with a rounded 
 gripe, must suit the shape of the cork. It is then taken 
 out of the machine, and, before it has had time to expand, is 
 rapidly fitted to the neck of the bottle, and driven home with 
 a wooden mallet. Expansion then takes place, and the bottle 
 is rendered air-tight, so that no damage is done to the wine. 
 
 If the whole of the wine were to be drunk when the cork was 
 removed, this plan would be amply sufficient. But there are 
 many cases where the bottle is opened, and only part of the 
 wine consumed. To re-cork the bottle would be too trouble- 
 some, and to leave it uncorked would spoil the wine. So the 
 Conical Stopper was invented, which fits the neck of any 
 ordinary wine-bottle, according to the depth to which it is intro- 
 duced, and, by a slight screwing movement, sufficient com- 
 pression is obtained to render the bottle air-tight. One of 
 these Conical Stoppers is shown in the illustration on page 352. 
 Sometimes they are made of cork, and sometimes of india- 
 rubber ; but the principle is the same in either case. 
 
 Perhaps some of my readers may have seen the Self-fitting 
 Candles, which require no paper to make them fit the candle- 
 stick. These are enlarged at the base, which is made in a 
 conical form, and slightly grooved. The " Candle-fixers " that 
 are so much in use at the present day are made exactly on the 
 same principle, being hollow cones of paper, which take the 
 place of the solid cone. 
 
 The Vent-peg of casks is another instance of the cone used 
 as a stopper. 
 
 Another example is to be found in the Blow-guns and 
 Arrows of tropical America. In some districts the base of the 
 arrow is fitted with a conical appendage of light cotton, rather 
 larger than the tube, but capable of compression, so that it 
 exactly fits the tube when pressed into it. In other districts 
 the cone is hollow, and made of some thin and elastic bark. 
 
 Some years ago one of our most eminent gun-makers hit 
 upon the same idea while making improved missiles for the 
 game of " Puff and Dart," and very much surprised he was 
 when I showed him the South American arrow, not only 
 with the same hollow corue at the base, but having also spiral
 
 352 NATURE'S TEACHINGS. 
 
 wings along the shaft, so as to give it a rotatory motion 
 as it passed through the air. The hollow cones of his darts 
 were made of india-rubher, but the shape of the two was 
 identical. 
 
 IF the reader will refer to the left-hand figure of the illus- 
 tration, he will see a beautiful example of the Conical Stopper 
 as existing in Nature. 
 
 This is the " Stopper," as it is popularly called, and, scien- 
 tifically, the " infundibuliform operculum." I prefer the former 
 term myself, as being less liable to misapprehension. 
 
 The Serpula lives in a shelly tube of its own construction, and 
 has the power of protruding itself when it desires to obtain 
 food, and of withdrawing itself within the tube when alarmed. 
 
 ANTENXA OP SERPULA. CONICAL STOPPER. 
 
 This movement is performed so rapidly, that the eye can 
 scarcely follow it, and the mechanism by which it is done has 
 already been described when treating of War and Hunting. 
 
 When it withdraws itself, the Stopper closes the mouth of 
 the tube with perfect exactness, so as to leave the inhabitant 
 in safety. The reader will see, on referring to the illustration, 
 how exactly similar is the Conical Stopper of Art to that of 
 Nature, and how the inventor of that article, as well as of the 
 self-fitting candle, the candle-fixer, the blow-gun arrow, and 
 the vent-peg, might have found prototypes of their inventions 
 in Nature, if they had only known where to look for them. 
 
 THE FILTER. 
 
 EVEN in a state of uncivilisation man has been driven to 
 invent a Filter of some kind. 
 
 The simplest kind of Filter is that which is used by the
 
 THE BOSJESMAN FILTER. 353 
 
 Bosjesman women when procuring water for the use of their 
 families. When, as often happens, the only water to be obtained 
 is to be found in muddy pools which have been trampled and 
 perturbed by thirsty animals, the women have recourse to a 
 simple, though rather repulsive, expedient. 
 
 Each woman is furnished with empty ostrich egg-shells by 
 way of water- vessels, and she also takes a couple of hollow 
 reeds. Over the end of one of these reeds she ties a bundle of 
 grass, and then plunges it as deeply as she can into the mud. 
 After a little while she sucks up the water through the tube, 
 the grass acting as a filter, and she then discharges it by the 
 second tube into the egg-shells. In this way the women will 
 obtain water, where none but themselves could have procured it. 
 As to the repulsive mode of obtaining it, no one can be fastidious 
 when dying of thirst. Sir S. Baker mentions that when he was 
 on his travels he managed in a halt to save up enough water 
 for a bath for himself and his wife. He was about to throw away 
 the soapy water, when the vessel was snatched from his hands 
 by two of his attendants, and the contents eagerly drunk. 
 
 The different varieties of the Filter which we use at the pre- 
 sent day are too familiar to need description. Whether they 
 be made principally of charcoal, which is a powerful disinfect- 
 ant, or of merely stones, gravel, and sand, they are all con- 
 structed on the same principle, namely, the straining out solid 
 substances, and allowing only the pure water to pass through 
 the interstices. 
 
 As to the Filters of Nature, they are almost innumerable. 
 In the first place, the Earth itself is the primary filter of all, 
 taking into itself all kinds of decomposing substances, separat- 
 ing them for the use of vegetation, and delivering the pure, 
 bright, and sparkling spring water which we so highly and 
 rightly value. The whole human body, again, is practically a 
 collection of the most elaborate and effective filters that the 
 mind of man can conceive. But we will pass to the more 
 obvious examples of filters as seen in animal life. 
 
 On the upper left-hand portion of the illustration may be 
 seen a long, fat, hairy creature, called popularly the Sea- 
 mouse, and known to zoologists as Aphrodite aculeata. 
 Although it inhabits the mud and sea-mud is about as 
 
 A A
 
 354 NATURE'S TEACHINGS. 
 
 noisome a substance as can be imagined it is clothed with a 
 garment of such beauty that the rainbow itself can scarcely 
 rival, and not surpass it. The hairs with which it is so pro- 
 fusely covered glitter and sparkle with every imaginable hue, 
 among which red and green seem to be predominant. 
 
 These hairs occupy the sides of the body, but in the upper 
 surface there is a thick coating of felted hairs, interwoven with 
 each other so closely that they can with difficulty be separated. 
 These hairs form a natural filter, strain away the mud from the 
 water, and allow the latter to pour itself upon the organs of 
 respiration. If, therefore, a specimen be examined when it is 
 
 U 
 
 APHRODITE. 
 DUCK'S BEAK. 
 
 first brought up by the dredge, the felted hair will always be 
 found to contain a considerable amount of mud, and much 
 washing is needed before the creature can be introduced into 
 an aquarium where the water is intended to be transparent. 
 
 I may here mention that the name of Aphrodite is a singu- 
 larly happy one. It signifies something that arises from the 
 foam of the sea, and was given to the goddess of beauty, 
 because in the ancient myths she was said to have sprung from 
 the foam of the sea. Unpoetical as it may appear, the German 
 word Meerschaum, which is so familiar to us in connection with 
 pipes, is the exact equivalent of Aphrodite. 
 
 BELOW the Aphrodite is a figure representing the filtering 
 apparatus which is found in the beak of the duck. This sin- 
 gularly beautiful apparatus is well worthy of examination, and 
 the more important details of its structure can easily be made 
 out by the unassisted eye. 
 
 In the first place, the upper half of the beak, or upper
 
 THE DUCK'S BEAK. 355 
 
 mandible, as it is scientifically called, is furnished along its 
 edges with, a row of curved horny projections, very like the teeth 
 of a comb, and each of them coming to a point. There are some 
 fifty or sixty of these teeth on each side, and they are regularly 
 graduated in size, being longest in the middle of the beak, and 
 becoming very short at either end. They are set diagonally, 
 with the tips pointing backwards. The edges of the lower 
 mandible are turned up in a sort of fold, on the outside of which 
 is a row of grooves corresponding with the teeth of the upper 
 mandible, and, like them, being set diagonally. 
 
 These teeth and grooves would of themselves make a very 
 efficient filter, but they are further aided by the tongue. This 
 is thick, fleshy, and very mobile ; so much so, indeed, that when 
 the mouth is opened the tongue is automatically thrust forward. 
 The edges of the tongue are, like those of the mandibles, 
 furnished with a filtering apparatus. Instead, however, of being 
 horny and stiff like those of the mandibles, they are mem- 
 branous and exceedingly delicate. Indeed, in order to see them 
 properly, it is necessary to place the tongue under water, so 
 that the membranous filaments shall be floated apart instead of 
 clinging together by their own weight. 
 
 The whole of this apparatus is abundantly supplied with 
 nerves, and is evidently a most exquisite instrument of touch. 
 The reader will now understand the peculiar movements of 
 a duck's beak while feeding. Although the bird can and does 
 eat solid food, such as barley, and, by reason of its superior 
 width of beak, will very much defraud the poultry in a yard 
 where ducks and hens are kept together, it is chiefly fitted for 
 extracting nourishment from water, and will find abundant 
 subsistence where a hen would die of starvation. 
 
 When the beak is plunged into the water, the mandibles are 
 rapidly opened and shut, the tongue incessantly working back- 
 wards and forwards between them. Consequently, not only 
 are the solid parts of the water strained between the comb of 
 the upper beak and the grooves of the lower, but they undergo a 
 further sifting or filtering from the delicate fibrils which fringe 
 the edge of the tongue. 
 
 ANOTHER familiar example of the Filter is to be found in the 
 jaw of the Greenland Whale. In this animal, as well as in its 
 
 A A 2
 
 356 NATURE'S TEACHINGS. 
 
 congeners, the "whalebone," or "baleen," as it is more pro- 
 perly called, is so formed that it allows liquids to pass through 
 it, while it retains solids. Feeding as it does upon small 
 marine matters, it would starve but for the filtering power of 
 the baleen, which enables the animal to take into its vast 
 mouth the sea-water with its inhabitants, and to expel the 
 water through the plates and fibres of the baleen, while retain- 
 ing the animals. 
 
 The process of filtering, as well as the structure of the 
 baleen, is so familiar that it does not need further description. 
 
 WE will now proceed to another filter, which is used in the 
 air, and not in water, namely, the Mouth-guard or Respirator 
 of the fork-grinder. 
 
 There is, perhaps, no trade which is more destructive of 
 human life than that of the fork-grinder was until the peculiar 
 respirator was made obligatory. The minute particles of steel 
 thrown off by the grindstone fills the air, and were necessarily 
 inhaled. Now, the human lungs are capable of enduring very 
 bad treatment, but the introduction of steel-dust into them is 
 more than they can bear. Consequently the duration of human 
 life was very short, consumption almost invariably setting in 
 at an early age, and carrying off the men before they had 
 achieved middle age. 
 
 Nor did the mischief end there. It was bad enough that life 
 should be shortened, but far worse that it should be wasted, as 
 was mostly the case. The men, knowing what their fate must 
 be, were simply reckless, and plunged into all kinds of 
 debauchery, under the plea of "a short life and a merry one." 
 They knew no better, and could scarcely be blamed for their 
 mode of living. And, as a matter of course, each succeeding 
 generation was worse, smaller, and feebler than the preceding. 
 
 Then there came the invention of the Magnetic Respirator, 
 by which the fork-grinder's trade was rendered as healthy as 
 any other. It was made of steel- wire gauze, and magnetised, 
 so that the floating particles of steel were not only stopped in 
 their progress to the lungs, but arrested by the magnetism, and, 
 so to speak, taken prisoners by it. 
 
 Even a well-made respirator of several layers, like those 
 which are used by persons suffering from weak lungs, would
 
 FORK-GRINDER'S RESPIRATOR. 357 
 
 have been useful, but the addition of magnetism doubled the 
 efficacy while greatly diminishing the cost, a single layer of 
 wire being quite adequate to the office, and was, in fact, quite a 
 stroke of genius. 
 
 The value of this invention is at once shown by the many 
 complaints which the workmen made when the Respirator 
 was first introduced. They complained that the apertures of 
 the Respirator became so choked that they could not breathe. 
 This was perfectly true, but the complaint showed the real 
 value of the instrument. 
 
 It was necessary for the workmen, every now and then, to 
 clear off the innumerable particles of steel which adhered to the 
 
 SPIRACLE OF FLY. BESPIRATOH OF FOBK-OBIWDKB. 
 
 magnetised wires, and impeded respiration. But they never 
 seemed to realise the fact that, if it had not been for these 
 wires, all the particles would have been drawn into the lungs, 
 and gradually choked them up, brought on inflammation, and 
 extinguished their life altogether. And, with the usual 
 repugnance to new ideas which is inherent in undeveloped 
 minds, the men stoutly resisted the introduction of the 
 Respirator, and did their best to reject an invention which 
 doubled the length of their lives, and enabled them to find 
 long happiness in the world instead of brief pleasure ended by 
 sure and painful death. 
 
 Now, we will see how the principle of the Respirator is 
 carried out in Nature. 
 
 On the left hand of the illustration is drawn one of the most 
 perfect Respirators, or air-filters, if we may use the term, that 
 can be imagined. Perhaps some of my readers may know that 
 insects do not breathe as we do. They have no lungs, but their 
 entire system is permeated by air-vessels, just as is our system
 
 358 NATURE'S TEACHINGS. 
 
 with blood-vessels, and therefore the air, instead of being 
 restricted to the lungs, is conveyed to every part of the insect, 
 the air-vessels extending to the very tips of the wings and 
 antennae, and to the claws of the feet. 
 
 Xeither does the insect receive the air through mouth or 
 nostrils as we do. Along the sides of the body are certain oval 
 apertures called " spiracles," from the Latin word spiro, which 
 signifies breathing. These spiracles can easily be seen by 
 examining an ordinary silkworm. They are situated in the 
 soft and flexible skin which connects the rings or segments of 
 which all insects are composed, and pass directly into two 
 large air-tubes which run on either side of the body. 
 
 It is evident that since an insect is so thoroughly permeated 
 with air, it must be furnished with means to render that air as 
 pure as possible, and at all events to preserve the respiratory 
 system from being choked with dust or other adventitious sub- 
 stances. 
 
 How important the air is to an insect can easily be seen by 
 dipping it in oil, or even brushing an oiled feather on its sides 
 so as to fill up the spiracles. A man under the hands of the 
 hangman or garotter could not die more swiftly, so much does 
 an insect depend on air. In fact, an insect is almost wholly 
 composed of air-tubes, but for which the great thick-bodied 
 dor-beetles could never use their organs of flight. 
 
 Of course, although the spiracles can act as filters as far as 
 the air is concerned, they cannot be analysts, and consequently 
 insects are peculiarly sensitive to a bad atmosphere. There is, 
 for example, the well-known " laurel-bottle " of entomologists. 
 A few young laurel-leaves are crushed and placed in a bottle. 
 As soon as an insect is introduced, it breathes the prussic acid 
 which is exhaled from the leaves, and at once dies. 
 
 So it is with the more delicate " death-bottle," into which a 
 little cyanide of potassium is introduced, and covered with 
 plaster of Paris. The plaster prevents the poison from touching 
 the insects and damaging their beautiful colours. It permits 
 the deadly vapour to roll through its interstices ; consequently, 
 even the large-bodied moths, which are tenacious of life almost 
 beyond credibility, can barely run round the bottle, when 
 they roll over, and expire almost without a struggle, the 
 venomous atmosphere having saturated the entire body.
 
 SPIRACLES OF INSECTS. 359 
 
 All entomologists know that the spiracles act as sieves, pre- 
 venting any extraneous objects from gaining admission into 
 the breathing-tubes. But, unless they have had personal expe- 
 rience, they cannot appreciate the efficacy of the spiracle 
 when acting as a respirator. Even the microscope, though it 
 may magnify the object to any extent, does not show the 
 wonderful filtering power of the spiracle. The figure in the 
 illustration represents a spiracle of the common " blue-bottle " 
 fly, and any one who wishes to examine such an object for 
 himself can have but little difficulty in doing so, especially in 
 the warm season of the year. 
 
 How effectual is the barrier thus interposed by Nature 
 between the external world and the interior of the insect may 
 be inferred from the following narrative : 
 
 Many years ago, while absorbed in the comparative anatomy 
 of insect structure, I believed myself to have hit upon a plan 
 for injecting the minutest of tubes with mercury. So I took 
 a male cockroach, placed a vessel of mercury in the receiver 
 of an air-pump, and suspended the cockroach exactly over it. 
 As the reader will fully have surmised, my idea was, first to 
 exhaust the air from the inside of the insect, then to plunge it 
 into the mercury, and then to admit the air, which, at a pres- 
 sure of fifteen pounds to the square inch, was likely to drive 
 the mercury into the smallest of tubes. Such a plan was very 
 successful with ordinary tissues, and might succeed with insects. 
 
 Accordingly, I exhausted the air from the vessel in which 
 the cockroach was placed, and kept it in a state of exhaustion 
 for a whole day, so as to prove that every particle of air was 
 withdrawn from the insect. I then plunged the cockroach 
 deeply beneath the mercury, and admitted the air, hoping that 
 the severe pressure would drive the mercury into the respira- 
 tory vessels. But not one particle of the mercury could pass 
 through the wonderful filter with which the cockroach had 
 been provided, and, except that I had learned the power of 
 the spiracle, I might have saved both the time and trouble. 
 
 It is worthy of notice that, almost countless as are the species 
 of insects, no two of them possess exactly the same structure of 
 the spiracles, the individuality being marked as clearly in these 
 tiny organs as in the entire insect.
 
 USEFUL ARTS. 
 
 CHAPTER V. 
 
 THE PRINCIPLE OF THE SPRING. THE ELASTIC SPRING. 
 ACCUMULATORS. THE SPIRAL SPRING. 
 
 Springs and their various Structure. The Elastic Spring. The Boy's Catapult 
 and its Powers. The Pistolograph, its Principle, and Uses to which it can be 
 put. Leaf -rolling Caterpillars, and their Way of Work. The Carriage 
 Spring. The Horse's Hoof and its complex Structure. Fungi and their 
 united Power. The Chinese Cross-how. The ancient Balista. Skull of 
 the Crocodile. Bones of young Children. The Spiral Spring and its many 
 Uses. The Toy-gun. The Needle-gun. Valved Brass Instruments. 
 Watch and Clock Springs. The Bed Spring. Parallels in Nature and Art. 
 Buffers of Railway Carriages. Spring Solitaires. The Bell Spring. 
 Spiral Springs in Vegetable Tissues. Poison Cells of various Marine 
 Animals. Effects of the Spiral Springs. 
 
 ELASTIC SPRINGS. 
 
 HERE we come upon a subject so large, that it is difficult 
 to define its exact requisite limits. The principle of the 
 elastic spring pervades all Nature, and the numerous adapta- 
 tions in Art are closely, though perhaps not directly, attri- 
 butable to the wide distribution of the spring in Nature. 
 
 There is, for example, the simple elasticity which enables a 
 tree, when bowed by the wind, to spring back so soon as the 
 pressure is removed, and which, indeed, is the power which 
 enables a bow to propel an arrow. Then there are spiral 
 springs innumerable, many of them so minute that they can 
 only be seen by the aid of the microscope, and there are many 
 springs which exhibit their elasticity by their power of exten- 
 sion and shortening, just as is done with the elastic fabrics 
 which are so much in vogue at the present day, and which 
 seem so necessary to ordinary comfort that we feel disposed to 
 wonder how our forefathers managed without them.
 
 ACCUMULATORS. 361 
 
 "We will now proceed to examine some of these springs in 
 detail. 
 
 THERE is one form of elastic spring which has of late years 
 become more familiar than agreeable, namely, the toy which is 
 learnedly called a " catapult," though it has little in common 
 with the ancient weapon whose name it bears. 
 
 As may be seen by reference to the illustration, it consists 
 of one or more india-rubber straps attached to a fork-like 
 handle, and carrying a small pouch in which is contained the 
 missile. Although it is not remarkable for accuracy, it can 
 throw a stone or a bullet a considerable distance, and its power 
 can be very quickly increased by adding to the number of the 
 straps. Thus a catapult has been made which was capable of 
 sending a small pistol bullet through a wooden board, so that 
 the child's toy might really become a dangerous weapon. 
 
 Indeed, cases are known where the catapult has hurled a 
 stone with fatal effect upon human beings. In my own neigh- 
 bourhood there are many examples of glass being pierced by 
 stones thrown from catapults just as if they had been subjected 
 to bullets shot from firearms, the holes being quite small and 
 round. 
 
 The power of accumulating force by increasing the number 
 of springs was utilised by Mr. Scaife, when he invented his 
 wonderful photographic machine which he termed the " Pisto- 
 lograph," on account of the sound which was produced when 
 the portrait was taken. 
 
 The idea was simple enough, though the practice of it was not 
 so easy. He wished to be able to take a photograph with an. 
 exposure of the least possible time, and thus to attain freedom 
 and action, instead of the dull stiffness which generally charac- 
 terizes photograph portraits. The mode which he adopted was 
 by introducing a peculiarly sensitive film, which would take 
 an impression in a mere moment, and then arranging the 
 machine so that an exposure of more than a moment was 
 impossible. 
 
 This was done by covering the lens with an exactly fitting 
 door, revolving on a pivot. The axis on which the door 
 revolved was attached to a number of india-rubber bands, 
 exactly like those which are used for confining papers. As the
 
 362 NATURE'S TEACHINGS. 
 
 power of the springs increased with their numoer, it naturally 
 followed that the rapidity of the revolution was in exact ratio 
 with the number of the bands, so that the duration of exposure 
 to light could be measured with tolerable accuracy. 
 
 So wonderfully well did this plan succeed that photographs 
 of eclipses were taken with perfect accuracy, a matter of great 
 importance when time has to be considered. Horses were also 
 taken at full gallop, so as to display their action, and the 
 crowning achievement was the photographing of a cannon in 
 the act of firing, and the bursting of a charged shell. So rapid 
 is the action of the instrument, that in several cases where a 
 cannon or mortar had been photographed, even the track of the 
 ball or shell is visible. 
 
 It necessarily followed that when the springs caused the 
 circular cover to revolve with such rapidity, they made it close 
 
 LEAF-ROLL1XO NESTS. 
 
 with a sharp report, and so gave rise to the name of the 
 machine. Moreover, as it had to be used for rapidly moving 
 objects, it was not fixed on a pedestal, but was held in the hands, 
 while aim was taken at the object, just as with a pistol. When 
 the observer thought that he had his aim correct, he touched a 
 trigger, round spun the cover, and the photograph was taken. 
 
 ON the right hand of the illustration is seen the Catapult, 
 made with several springs, and on the left is shown an example 
 of the Accumulator as formed by Nature. 
 
 The reader may probably be acquainted with the Leaf- 
 rolling Caterpillars, of which there are so many. I had often 
 inspected these curled leaves, and, on comparing them with the
 
 LEAF-ROLLINO CATERPILLARS. 363 
 
 size of the caterpillars, had noticed that the muscular strength 
 of the insect was quite inadequate to the work which was done. 
 That much of it was owing to the " bowsing " system, which 
 has already been described when treating of the Toggle-joint, 
 was very probable, but that some other force must be employed 
 was evident. 
 
 On unrolling a leaf, the hidden force was at once explained, 
 and showed itself to be a system of accumulators exactly like 
 those of the pistolograph or the catapult. The caterpillar spins 
 successive belts of silken threads, and affixes them to the leaf, 
 as shown in the illustration. These threads are nearly as 
 elastic as the india-rubber bands of the 'catapult, and accord- 
 ingly draw the leaf together. Another set of belts is added 
 above the former, and, as they harden and contract in the 
 air, they roll the leaf still further. The first row is then 
 shortened and tightened, and a third and fourth row are 
 added in the same fashion. So elastic are these belts, that if 
 the leaf be carefully handled it can be almost wholly unrolled, 
 and will spring back again as soon as the force is removed. 
 
 ANOTHER form of accumulated force may be seen in the 
 ordinary Carriage Spring, one of which is shown in the illus- 
 tration. It is made of a number of strips of elastic steel lying 
 upon each other, and suffered to play upon each other by 
 means of slots and rivets. The weight being placed in the 
 centre, it is evident that this very ingenious spring is really an 
 elastic girder, yielding to sudden pressure, and recovering 
 itself when that pressure is removed. 
 
 INGENIOUS as is this spring, it has many parallels in Nature, 
 one of which is here given. 
 
 It is popularly thought the hoof of the horse is a solid mass 
 of horn destined to protect the feet against hard and rough 
 ground. Such certainly seems to be the opinion of farriers, 
 who, in shoeing horses, act exactly as if the horn of the hoof 
 were structureless ; whereas it is a marvel of complicated 
 mechanism. On looking at the exterior of a horse's hoof, it 
 will be seen to be marked with a vast number of very fine, 
 but easily visible longitudinal lines, looking as if they were 
 scratches from a very fine needle. If the hoof be removed
 
 364 NATURE'S TEACHINGS. 
 
 from the foot, and examined upon the interior, it will be seen 
 that each of the apparent scratches signifies the edge of a very 
 thin plate of horn, not so thick as the paper on which this 
 book is printed. The hoof, in fact, is built up of multitudinous 
 plates of horn, set side by side, and each acting as a separate 
 spring. It is this beautiful structure which allows the horse 
 to tread without a jar being sent through its whole system by 
 every step which it takes. 
 
 A similar structure is to be found in all hoofed quadrupeds, 
 and is especially noticeable in the case of the Elephant. All 
 those who have watched the walk of an Elephant, no matter 
 what its size may be, must have been struck with the curious 
 noiselessness of its movements. Its weight may be measured 
 by tons, and yet the enormous animal steps as noiselessly as a 
 cat. On examining one of the hoofs, after it is removed from 
 
 HORSE -II OOF. CABBIAGE SPRING. 
 
 the foot, the cause of this marvellously silent tread is perfectly 
 evident. The whole of the hoof is composed of nearly parallel 
 horny plates, and by their united action they produce the 
 required result. 
 
 Each plate in itself is very feeble, but, when united as they 
 are at the ends, they afford mutual support to each other. 
 Similarly the separate feathers in a couch would be crushed by 
 a comparatively slight weight, but when a number are con- 
 fined together they support each other, and form the soft, 
 yielding couch with which we are so familiar. Horsehair, 
 when used as the>stufling for a couch or chair, acts in the 
 same way, and so do the fine filaments of wool when used 
 under the name of " flock."
 
 CHINESE CROSS-BOW. 365 
 
 Another good example of the power of accumulated force, 
 although it has no direct relation to the spring, is the well- 
 known fact that fungi, which are separately so fragile, are 
 capable of lifting and retaining in the air stones so large that 
 two men could hardly carry them. Were the stones laid down 
 upon the fungi, the latter would be crushed, but, as they grow 
 beneath the stones, they accumulate their powers, and slowly, 
 but certainly, raise the weight from the ground. 
 
 THIS very principle of accumulated force has long been used 
 in weapons of war, and I possess several examples of such 
 weapons. One of them is a Chinese repeating Cross-bow, which 
 was taken at the capture of the Peiho Fort, and was really a 
 formidable wall-instrument, carrying a reserve of arrows, and 
 
 JAWS OP CEOCODILB. CHINESE CEOSS-BOW. 
 
 delivering them with great rapidity. In point of fact, it 
 consists of three bows, placed upon each other, and playing 
 upon each other just as do the portions of a carriage spring. 
 Such strength is thus obtained, that the bow cannot be drawn 
 by hand, but is worked with a lever, as shown in the illustration. 
 The whole machinery of the weapon, including the self-notch- 
 ing and self-supplying system, is very interesting, but is outside 
 our present object. The very powerful bow of the ancient 
 Balista was made on the same principle, and was strong enough 
 to throw large stones and wooden beams. 
 
 I also have bows in my collection which are strengthened on 
 the same principle, though not exactly in the same manner. 
 There are several Indian, Chinese, and Japanese bows which 
 are curved almost like the letter C, and have to be reversed 
 when strung. These bows are of no very great size, but 
 possess wonderful elasticity. They owe the latter quality to
 
 366 NATURE'S TEACHINGS. 
 
 sundry layers of sinew which have been affixed to the back 
 when wet, and which add enormously to the power of the bow, 
 while they very little enlarge its dimensions. 
 
 Another bow, made by the natives of Vancouver's Island, has 
 the back strengthened by a number of cords spun from sinew 
 fibres, and possessing the strength and elasticity to which we 
 are accustomed in the strings of the harp, guitar, or violin. 
 
 WE will now turn to a parallel in Nature. This is to be 
 found in the lower jaw of the Crocodile, as is pointed out by 
 Professor Owen, in his work on the " Skeleton and the Teeth." 
 
 All persons who have a smattering of anatomy are aware 
 that even in the human body the most solid bones of the adult 
 were originally composed of several pieces, and that they only 
 become fused together in course of time. The jaw-bones, for 
 example, were once so composed, and in the Crocodile the 
 junction is never completed, the pieces of bone remaining 
 separate, but being pressed firmly against each other during 
 life. 
 
 I have now before me the skull of a Gangetic Crocodile, in 
 which, although the animal was an adult when killed, the 
 bones of the long lower jaw are so loose that unless they were 
 tied together the jaw would fall to pieces. 
 
 This analogy between Art and Nature is thus described by 
 Professor Owen in the work which has just been mentioned : 
 
 " The purpose of this subdivision of the lower jaw-bone has 
 been well explained by Conybeare and Buckland, by the 
 analogy of its structure to that adopted in binding together 
 several parallel plates of elastic wood or steel to make a cross- 
 bow, and also in setting together thin plates of steel in the 
 carriage spring." 
 
 Dr. Buckland also adds : " Those who have witnessed the 
 shock given to the head of a Crocodile by the act of snapping 
 together its thin, long jaws, must have seen how liable to 
 fracture the lower jaw would be were it composed of one bone 
 
 only The splicing and bracing together of thin flat 
 
 bones of unequal length and of varying thickness afford com- 
 pensation for the weakness and risk of fracture that would 
 otherwise have attended the elongation of the parts." 
 
 A good example of the value of this structure of bone may
 
 SPIRAL SPRINGS. 
 
 367 
 
 be round in young children. Before they are old enough to 
 take care of themselves they are perpetually falling down, and 
 never hurting themselves. I have seen a little girl of five 
 years old roll from top to bottom of a lofty staircase. It looked 
 as if the child must be killed, but she was only giddy with her 
 many revolutions, and a little bruised about the elbows. The 
 reason of this curious immunity from injury is, that the bones, 
 especially those of the skull, are not completely united, and so 
 act on the principle of the compound spring. 
 
 THE SPIRAL SPRING. 
 
 THIS subject is so large, and there are so many examples, 
 both in Art and Nature, that it is not very easy to make selec- 
 tions which will sufficiently answer the purpose. 
 
 WATER-LILY. L 
 
 POISON-CELL OP HELIANTHOID. 
 
 ANTHEBOZOIDS. 
 
 SPIRAL SPRING. BED SPRING. 
 
 WATCH SPRING 
 
 The upper left-hand figure of the illustration represents the 
 ordinary Spiral Spring made of wire, and used for its power of 
 resuming its shape when compressed. In early childhood most 
 boys have had practical experience of this spring in the toy 
 guns and cannons with which they are supplied. The spring 
 is compressed by the ramrod, and held in its place by a catch. 
 If a pellet be placed in the gun, and the catch released by 
 pulling the trigger, the spring flies back to its former shape, 
 and drives the pellet. 
 
 An exactly similar spring is used in the well-known "Needle-
 
 368 NATURE'S TEACHINGS. 
 
 gun," the spring driving a needle through the explosive mix- 
 ture, and so igniting the charge. 
 
 Our brass instruments would be very badly off without the 
 spiral spring, which is placed under the pistons. The elasticity 
 allows the pistons to be pressed down, and when the fingers 
 are raised the pistons spring up again. 
 
 Another form of this instrument is seen on the right of the 
 ordinary spring. This is used in the manufacture of spring 
 mattresses and couches, and is made thinner in the centre, so 
 as to allow of greater elasticity. 
 
 Below them is the spring which is used for watches and 
 clocks, one end being fastened to the rim of the barrel, and the 
 other to the pivot. When the latter is turned the spring 
 becomes " wound up," and, when released, keeps the works 
 going by pressing against them. Of the " pall-and- ratchet " 
 wheel, by which the movements are retarded, we shall treat in 
 another place. 
 
 ON the left hand of the illustration are a few figures of 
 the Spiral Spring as seen in Nature. 
 
 On the extreme left of the group is a spiral cell taken from 
 the flower-stem of the "Water-lily. As the reader will see, it 
 is composed of a number of fibres laid parallel to each other, 
 and twisted into a hollow spiral. In order to exhibit its shape 
 the better, the spiral has been partially uncoiled. 
 
 On the extreme right is a corresponding spiral cell from the 
 common Lily, in which the spring power is given by two fibres 
 twisted in opposite directions. The reader will now under- 
 stand and admire the mechanism by which these plants attain 
 their great strength and elasticity, the stems being made of 
 myriads of these spiral fibres. 
 
 The oval body on the upper part of the illustration is a 
 poison-cell of a marine polyp, and is given here as an example 
 of an animal spiral spring, the others all belonging to the 
 vegetable world. 
 
 We shall see more of its structure a little further on, and 
 will not now examine it in detail. 
 
 The two remaining figures represent the remarkable objects 
 called Antherozoids, i.e. the living creatures of anthers. They 
 exist in vast numbers in the non-flowering plants, and inhabit
 
 " BUFFER " SPRINGS. 369 
 
 those parts which correspond with the anthers of the flowering 
 plants. When placed in water they have a curious way of 
 coiling and twisting themselves spirally, so as to make their 
 way through the water in a tortuous, but tolerably rapid, 
 course. This movement is effected by the contraction and 
 expansion of the spirally twisted filament. The upper figure 
 represents a group of Antherozoids in their cells, and the 
 lower is a much more magnified figure of a single Anthero- 
 zoid as it appears when free, and in the act of moving through 
 the water. 
 
 ON the accompanying illustration are many examples of 
 Spiral Springs, both natural and artificial. We will take these 
 in their order. 
 
 The upper left-hand figure represents the " Buffer," by which 
 the carriages of railway trains are prevented from jarring 
 against each other. 
 
 Perhaps some of my readers may be old enough to remember 
 the days of the old railway carriages that were connected by 
 short chains, and furnished with buffers that were merely 
 padded. As the train started a separate jerk was given to 
 every carriage by the tightening of the chains, and, as it 
 stopped, all the carriages bumped against each other in a most 
 unpleasant manner. Now, however, the buffers are furnished 
 with powerful springs, and are pressed strongly against each 
 other by means of screw-bolts, so that they form one con- 
 tinuous line. 
 
 In fact and here is another analogy between Art and 
 Nature a train, when properly made up, bears a close resem- 
 blance to a human spine, the carriages being analogous to the 
 vertebrae, and the spring buffers to the elastic cartilages 
 between the vertebrae. 
 
 Nowadays, owing to this arrangement, the whole train 
 moves together, and can be started and stopped so gently 
 that the passengers are hardly aware of movement or stoppage. 
 For example, one of my friends was in a train which came into 
 collision with some obstacle. The carriages in front were 
 dashed to pieces, and several of the passengers killed. His 
 carriage, however, which was nearly at the end of the train, 
 and had the benefit of all the springs, was hardly shaken, and 
 
 B B
 
 370 
 
 NATURE S TEACHINGS. 
 
 the inmates did not know for some little time that an accident 
 had occurred. 
 
 BUFFER OP RAILWAY ENGINE. 
 SUPPORTING SPRING OF RAILWAY CARRIAGE. 
 SPRING SOLITAIRE. 
 BELL SPRING. 
 
 MOSS DISCHARGING SPORES. 
 
 TENTACLE, WITH SPRINGS. 
 
 SPRING-CELL SPRING- SPRING-CELL 
 
 OF THREAD OP OP 
 
 MADREPORE. SEA- CORYNACTIS. 
 
 ANEMONE. 
 
 Below the buffer is a Wheel Spring, made exactly on the 
 same principle, but set perpendicularly instead of horizon- 
 tally.
 
 THE BELL SPRING. 371 
 
 THE two figures beneath the wheel spring represent an 
 object very familiar to us, namely, a Spring Solitaire, one 
 figure showing it as open, and the other as closed. In this 
 article the clasp is held in its place by a spring, and is only 
 released by pressure. 
 
 BELOW the solitaire is a very prosaic application of the 
 Spiral Spring, namely, that by which a house-bell is kept in 
 vibration after the force of the pull has ceased, and which 
 renders the bell, as Dickens happily remarks, so greedy to ring 
 after it has been pulled. 
 
 I made and employed a spring of a similar character in 
 closing the door of my parrot's cage. Polly is a wonderfully 
 clever bird, and a capital talker. First, she had a cage with 
 upright bars, two of which could be slid upwards by way of 
 a door. She soon found out the trick of the bars, and used 
 to escape, carefully replacing the bars afterwards. 
 
 When she was transferred to a metal cage, she discovered 
 that the door slid upwards, and began at her old tricks. So I 
 took a piece of galvanised iron wire, coiled it into a spiral 
 spring, fastened one end to the upper part of the door, and 
 the other by a hook to a staple at the bottom of the cage. 
 Consequently, when Polly lifted the door, and loosened her 
 grip for a fresh hold, the door closed itself again. So, after 
 awhile, Polly gave up the door, and now never tries to 
 open it. 
 
 PASSING to the upper right-hand corner of the illustration, 
 there is shown a portion of Moss as it appears when magnified, 
 and discharging its spores. When they are ripe a vast number 
 of little spiral springs are let loose, and shoot the sporules into 
 the air. 
 
 BLLOW the moss are four figures, which are, in fact, the 
 same object differently magnified, and seen from different 
 points of view. These peculiar organs are technically termed 
 " cnidaB," from a Greek word which signifies a nettle. The 
 appropriateness of the name we shall presently see. 
 
 I have already mentioned that the tentacles of various 
 marine animals are furnished with poison-cells. The object of 
 
 B B 2
 
 372 NATURE'S TEACHINGS. 
 
 these cells is to capture and kill the prey, and the mode of 
 doing so is very remarkable. 
 
 On the right and left of the illustration are two such 
 bodies, in which is seen a sort of elastic wire coiled spirally, 
 apparently without regularity, but really possessing a most 
 beautiful order. That on the left is the poison-cell of a Madre- 
 pore, and the other is the same organ in a Corynactis. No 
 sooner is the tentacle touched than the poison-cells are mecha- 
 nically acted upon. They are turned inside out, and the 
 coiled spring darts forth with wonderful violence. 
 
 Slight as is the dart, so fine that it cannot be seen except 
 with the aid of a tolerably powerful microscope, it is a terrible 
 weapon. Although it is projected with suflicient force to bury 
 itself to its base even through so tough an object as the 
 human skin, it could inflict but little injury, and would, indeed, 
 scarcely be felt. But it carries with it a most irritant poison, 
 which is apparently contained in the little capsule. These 
 cnidae are very plentiful in the tentacles of the Stinging Jelly- 
 fish, or Stanger, as it is often called, and are charged with a 
 terrible poison. 
 
 As is the case with all such poisons, its effects differ accord- 
 ing to the constitution of the being that is poisoned. There 
 are some persons, for example, who care no more for the sting 
 of a bee than for the prick of a needle, and there are those 
 whom a single bee-sting will bring almost to the gates of 
 death. So with the tentacles of the Stinging Jelly-fish and 
 those of the Portuguese Man-of-war, and there are persons who 
 are scarcely affected with the sting of the scorpion. 
 
 So it is with nettles. When I was a boy at school it was 
 thought necessary to wear an oak-leaf, or at least a portion of 
 an oak-leaf, on the 29th of May, and all who did not possess 
 this talisman might be flogged with nettles by those who did. 
 As the school was situated in the north of England, where the 
 oak puts forth its leaves late in the season, it was no easy 
 matter to obtain a veritable oak-leaf, and we used to take any 
 leaf that we could procure, and cut it round the edges into 
 the similitude of a suitable oak- leaf. 
 
 The effect of the nettles upon the boys was most curiously 
 diversified. Some cared nothing whatever for them ; others 
 suffered sharp but brief pangs ; while others, of whom I was
 
 THE " STANGER " JELLY-FISH. 373 
 
 one, endured the most lancinating pain at the time, and for 
 hours afterwards a hot, burning, fevered skin, and a heavy, 
 dull ache, accompanied by throbbings of the brain so violent 
 that it appeared as if the head would burst asunder at every 
 heart-beat. 
 
 The fact of this inequality has been throughout life a valuable 
 lesson to me, i.e. that a punishment which will nearly, if not 
 quite, kill one man, will be no punishment at all to another. 
 
 Of course I cannot answer for the effects of these very minute 
 cnidae upon others, but I can state that they nearly killed mc> 
 and that if I had been forced to swim another hundred yards, 
 I should have collapsed, sunk, and had a coroner's jury return 
 a verdict of " Found drowned in consequence of cramp." 
 
 On me the effects were as follows : First a slight, and then 
 a severe, tingling on the parts which had been struck. Then 
 sharp, darting pangs. Then a sudden shock as if a bullet had 
 passed through the breast from one side to the other. Conse- 
 quent collapse, and suspension of the office of both heart and 
 lungs. I once had to walk nearly two miles after being stung 
 by one of these dread animals, and how often I fell before 
 reaching my lodgings I dare not say, but certainly once in 
 every two hundred yards. 
 
 Even after partial recovery I should not have known my 
 own face. It was that of an old and wearied man of seventy, 
 grey, wrinkled, and withered ; and many months elapsed 
 before I felt myself sure that the weird-like bullet would not 
 drive through my breast, and leave me lying on the ground 
 gasping and speechless. 
 
 These dreaded tentacles can sting as fiercely when separated 
 from the animal as when they are conjoined to it, as I can also 
 testify from personal experience. 
 
 I have a natural alacrity in damaging myself, and there is 
 scarcely a representative bone in the body that I have not 
 fractured or dislocated, or both. Fortunately the cerebral 
 vertebrae have hitherto escaped. I have broken the right leg, 
 right arm, two ribs, and right collar-bone ; dislocated the right 
 ankle, and smashed nearly every bone of the right hand. At 
 present, the damage to the left side is restricted to two ribs ; 
 and I hope that the Genius of Ossifraction may now be content 
 with his work.
 
 374 NATURE'S TEACHINGS. 
 
 But I equally seem to have a natural affinity for the tentacles 
 of the Stangers, which deliver their envenomed darts just as 
 fiercely when they are separated from the Medusa as when 
 they are connected with it. 
 
 A curious example of this fact befell me in the present year 
 (1875). Seeing that there had been a steady southern gale, 
 which made Lundy Island and Hartland and Baggy Points 
 indiscernible, I dreaded my old foes, and, instead of bathing 
 from the " Pebble Ridge," took to the great " Nassau" Baths 
 at Westward Ho. I sadly missed the roll of the waves, and 
 the placid rapture of lying with outspread arms as the vast 
 Atlantic billows came rolling in, flinging up the great grey 
 boulders as if they were corks, and letting them roll down the 
 ridge again with a thundering, and yet soothing, sound. Three 
 miles or more inland may the thunder of the Pebble Ridge be 
 heard ; and at night, even though a storm be raging, tearing 
 the leaves off the trees in whirling showers, flinging great 
 branches into the air like ostrich plumes, and howling so that 
 one person can hardly hear another speak, the dull, low, con- 
 tinuous thunder of the Pebble Ridge is heard over all. I have 
 often rem lined awake at Bideford, simply on account of the 
 deep roar of the Pebble Ridge, as the rising tide rolled its vast 
 waves along the coast from Baggy Point, through Westward 
 Ho and Clovelly, to Hartland. 
 
 When there is a heavy sea, the " undertow " of these waves 
 is so great that even had no such things as Stangers existed, I 
 should not have ventured upon the Pebble Ridge. One of my 
 friends, a strong swimmer, was nearly drowned off that ridge 
 by the undertow ; and not long before I visited Westward Ho 
 a promising young man lost his life within a few yards of that 
 treacherous shore. 
 
 Much against my will, I went to the new bath, which is 
 always supplied with a running current of sea- water ; and I 
 had hardly swum the length of the bath before I felt the 
 familiar nettle-like sting in my foot. Fortunately it was only 
 caused by a small fragment of a Stanger's tentacle, which had 
 been severed from the animal and pumped into the bath, and 
 no harm ensued.
 
 USEFUL ARTS. 
 
 CHAPTER VI. 
 
 SPIRAL AND RINGED TISSUES. VARIOUS SPRINGS IN NATURE 
 
 AND ART. 
 
 Spiral Tissues, and their Structure and Uses. The movable Gas-lamp. Elastic 
 Tubes. Breathing-tubes of Insects, and their Spiral Wire. Ringed Tissues 
 and their varied Structure. Ringed Tissues applied to modern Dress. 
 Chinese and Japanese Lanterns. Proboscis of the House-fly. Trachea of 
 various Animals. Mutual Tendency of Rings and Spirals towards each 
 other. Fibres of the Yew-tree. Diving and Divers. Principle of the 
 Diving-bell. How it is supplied with Air. Structure of the Air-tubes. 
 Nests of the Water-spider. Diving by means of Tubes. Larva of the 
 Drone-fly, and its Mode of breathing. How to examine them. Leaping 
 Springs. The Skip-jack in Nature and Art. Skip-jack or Click Beetles. The 
 Spring-tail, Grasshopper, Kangaroo, Gerboa, and other Jumping Creatures. 
 
 SPIRAL AND RINGED TISSUES. 
 
 WE have now to consider the Spiral Tissue under another 
 aspect, i.e. that of acting as the internal support of an 
 exterior membrane. Ringed tissues are necessarily conjoined 
 with the Spiral, as they both discharge the same office, and in 
 some cases merge almost imperceptibly into each other in the 
 same specimens. This is most beautifully shown in the pro- 
 boscis of the common House-fly, to which reference will pre- 
 sently be made. 
 
 The subject is so large that only a comparatively small selec- 
 tion of examples can be made, the greater number belonging 
 to Nature, and not to Art. 
 
 We will first take the common movable Gas-lamp, with 
 its accompanying tube. It is at present the tube of which 
 we have to treat, the gas itself being reserved for a future 
 page. 
 
 It is necessary that, in order to enable the lamp to be moved 
 from one spot to another, the tube through which the gas
 
 376 
 
 NATURE S TEACHINGS. 
 
 passes must be so constructed that if it be bent, or even 
 coiled, it retains its form, and does not become flattened. In 
 order to obtain this object, a very long thin wire is coiled 
 spirally to a suitable length. Over this wire is sewn the casing 
 of the tube, which is afterwards made waterproof with elastic 
 varnish. A still simpler mode is by enclosing a spiral wire 
 within a tube of vulcanised india-rubber. It will be seen, then, 
 that by the elasticity of the spiral wire the tube must always 
 retain its shape, no matter how much it may be bent. 
 
 On the right hand of the illustration are shown the movable 
 Gas-lamp and tube, and a portion of the latter is given 
 
 TEACHBA OP INSECT, 
 WITH ITS SPIRAL THREAD. 
 
 TUBE OP GAS-LAMP, 
 WITH ITS SPIRAL WIBB. 
 
 with its spiral wire partially unwound, in order to show its 
 
 structure. 
 
 / 
 
 The large tubes which convey air to divers are made in the 
 same manner, as they would not only succumb to the pressure 
 of the water without the wire, but could not be dragged over 
 obstacles or round corners without collapsing. It often happens 
 that a diver is obliged, when surveying a sunken ship, to 
 traverse the whole of her interior, descending ladder after 
 ladder, and entering every cabin in the ship. This could 
 not be done but for the internal coil of wire within the tube. 
 Reference will presently be made to the subject of diving. 
 
 ON the left hand is seen an object that looks something like 
 a branch hollowed very thin. It is a magnified view of part 
 of the Trachea or breathing-tube through which air is con-
 
 TUBE OF THE HOOKAH. 377 
 
 veyed into the system of an insect. These breathing-tubes 
 ramify to every portion of the body of an insect, even pene- 
 trating to the extremities of the antennae, the wings, and the 
 legs. It is obvious that as these organs are in tolerably con- 
 stant movement, and the legs are much bent at every joint 
 by the action of walking, the air-tubes which run through 
 them must possess the same qualities as those of the gas-lamp 
 and diver. 
 
 If one of these tracheae be removed and placed under the 
 microscope, it will be seen to be constructed in a manner 
 exactly similar to that which has been described. Within the 
 membrane which forms the tube proper there is a very fine, 
 but very strong thread, which is coiled exactly like the wire 
 spring. It is not attached to the membrane, and so strong is it 
 that, although it is all but invisible to the naked eye, it can be 
 drawn out as shown in the left-hand figure of the illustration. 
 
 TRACHEA OF DBAGON-FLY LARVA. TUBE OP HOOKAH. 
 
 If laid on a piece of glass, it immediately tries to recoil itself, 
 and for some little time will twist and curl about as if it were 
 alive. 
 
 ON the above illustration are two similar examples of 
 the spiral thread with a flexible tube. The right-hand 
 figure represents one of the many forms of the water-pipe, 
 whether known as Hookah, Narghile, or Hubble-bubble. In 
 the simpler forms of this pipe, such as the latter, the inhaling- 
 tube is quite straight, and the bowl is held in the hands of the 
 smoker. In the more refined pipe, however, the tube is very 
 long, flexible, and made elastic by an inner spiral wire. 
 
 Perhaps the reader may remember that the larva of the 
 Dragon-fly is a most remarkable creature in consequence of
 
 378 NATURE'S TEACHINGS. 
 
 its methods of propulsion and respiration. The water is taken 
 into the interior of the hody through a peculiarly formed 
 aperture, and then ejected with such violence as to drive the 
 body forward on the same principle as that which causes a 
 rocket to ascend. 
 
 The figure on the left hand of the illustration is a repre- 
 sentation of the abdomen of this larva rather magnified, and 
 opened so as to show the interior. On either side run the two 
 principal breathing-tubes, through the delicate membranes of 
 which the spiral thread can plainly be seen. 
 
 These tubes are connected with a smaller set, and they with 
 a still smaller, so that at last they are of such tenuity that they 
 can scarcely be distinguished without the use of a glass. But, 
 however small they may be, they are always fitted with the 
 spiral thread. 
 
 WE now come to the cases where the membrane is supported 
 by a series of rings, and not by a single spiral wire. 
 
 In the right-hand division of the illustration are two speci- 
 mens of objects which shall be nameless, but which were drawn 
 per special favour at a milliner's shop. Although the day has 
 now happily gone by when the larger object was in general 
 wear, and seemed to be irrepressively increasing in dimensions, 
 certain modifications of it, under various names, have made 
 their appearance in almost every book of fashions and every 
 large milliner's shop. 
 
 Here we have the external membrane made of linen, calico, 
 merino, or similar material, distended by a number of elastic 
 rings set at tolerably even distances from each other. 
 
 The two small objects represent the handy little paper 
 lanterns so common in China and Japan. They are composed 
 of an external coat of tough tissue paper, so thin that it allows 
 the light to pass through it with tolerable freedom, and of an 
 internal series of elastic rings, which not only support it and 
 preserve its cylindrical shape, but allow it to be folded up flat 
 when not wanted. 
 
 I possess a singularly ingenious lantern of this kind, made in 
 Japan, and displaying the thoroughness of work which charac- 
 terizes that nation. It is five inches in diameter, and the 
 lantern itself is affixed at either end to a circular wooden cap
 
 RINGS AND SPIRALS. 
 
 379 
 
 the upper fitting over the lower. Consequently, when the 
 lantern is shut, it is entirely enclosed between these two 
 caps, which effectually preserve it from harm. It is deli- 
 cately finished, and has no less than thirty rings, made of 
 very narrow strips of bamboo. The upper cap has a little 
 trap-door through which the candle can be admitted and 
 trimmed, and in its centre is a small round hole for the passage 
 of air. 
 
 IN the left-hand division of the illustration are shown 
 several examples of ringed and spiral tissues belonging to the 
 
 
 SPIRAL AND RINGED FIBBB 
 (VEGETABLE). 
 
 KAMELESS OBJECTS. 
 
 PAPEB LANTEKNS. 
 
 vegetable world, in which the principle is exactly the same as 
 that of the Chinese lantern, &c. That on thp right hand is an 
 example of simple rings within a membrane. The central 
 figure shows a double spiral, which produces very much the 
 appearance of a series of rings ; and on the extreme left is an 
 interesting example which shows the transition in the internal 
 supports from spirals to rings. 
 
 I have already mentioned that the proboscis of the House-fly 
 exhibits this modification. If one of these objects be placed 
 under, a moderate power of the microscope the half-inch is
 
 380 
 
 NATURE S TEACHINGS. 
 
 quite enough and examined, it will be seen that there are 
 some large tracheae, just like those of the Dragon-fly larva, 
 on each side of the proboscis, and that, where the end is 
 widened and flattened into a sort of disc, their place is taken 
 by a set of very much smaller tracheae, coming nearly to a 
 point, and each being supported internally by a series of 
 incomplete rings, shaped very much like the letter C. A 
 slide containing this object well mounted can be purchased at 
 any optician's for a shilling. 
 
 THE trachea, or windpipe, as we call it, of all vertebrate 
 animals, man included, is formed on exactly the same principle, 
 as any one may see by going to a butcher's shop, and looking 
 
 at the trachea, or windpipe, by which the lungs, or " lights," as 
 they are called, are suspended. Were it not for this structure, 
 we should not be able to bend our necks or turn our heads. 
 
 The accompanying illustration shows the tracheae of three 
 well-known creatures. The left-hand figure is the trachea of 
 an Ox, the central figure that of a Pig, and the right-hand 
 figure that of a Goose. Mr. Tufien West, who made the 
 drawings, sent with them the following remarks : 
 
 " The tracheae of animals furnish some very interesting 
 examples of variation in the form and arrangement of the 
 rings. Their purpose, perhaps, one can but guess at in some 
 cases; but doubtless, as being works of the Master Builder, 
 careful study would be repaid.
 
 TRACHEA. 
 
 381 
 
 " In the Ox the rings are very strong and close, and in form 
 like a horse- shoe with the ends approximated'. 
 
 " In the Pig the incomplete rings are broad at one part, and 
 narrow on the opposite side, with a tendency to spiral arrange- 
 ment. I imagine that this would make a very rigid tube, and, 
 indeed, it feels so in the hand. 
 
 " Then, in the Goose, the narrowed lower part is that which 
 is figured just before the trachea reaches the sternum. The 
 (complete) rings are twice as broad in one half as in the other, 
 and by the alternate disposition of these differing widths, a 
 tube is formed of great flexibility fore and aft, but almost 
 absolutely rigid in the lateral direction. This seems to be so 
 
 KINGED TISSUES OP SUGAB-CANE 
 
 VEGETABLE SPIRAL TISSUES TENDING TO KINGS, 
 
 marked an evidence of design as to be calculated to greatly 
 raise our admiration." 
 
 WE have seen several examples of ringed tissues tending to 
 the spiral form, and it is but natural that we should expect to 
 find spiral tissues tending to the ring. 
 
 In the accompanying illustration the two left-hand figures 
 represent the curiously modified ringed tissue which is to be 
 found in the sugar-cane, the left-hand figure being much more 
 magnified than the other. 
 
 The other figures represent four examples of vegetable spiral 
 tissues, in which it will be seen that there is a tendency to form 
 rings, and that if a number of rings were substituted for the
 
 382 NATURE'S TEACHINGS. 
 
 spiral, and the object viewed in a slanting direction, it would 
 be almost impossible to distinguish between the ring and the 
 spiral. 
 
 Among the most remarkable of these examples are the two 
 right-hand figures. That on the extreme right represents a 
 spiral vessel taken from the so-called root, or " rhizome," of the 
 Water-lily, and the other is a similar vessel taken from a 
 branch of the Yew-tree. It has been suggested that to this 
 spiral structure is due the proverbial elasticity of the yew-tree, 
 which has from time immemorial rendered it the best wood for 
 the manufacture of bows. 
 
 DIVING AND DIVERS. 
 
 IT has already been mentioned that the flexible tubes used by 
 modern divers are constructed on the model of several structures 
 belonging to the animal and vegetable kingdoms. 
 
 We will now see how they are utilised. 
 
 IN the earlier stages of the diver's art the Diving-bell 
 afforded the only means of gaining access to the bed of the sea, 
 even in comparatively shallow waters. The mode in which 
 this result was obtained was simple enough, and though it 
 carried with it the germs of still greater improvements, was 
 but limited and uncertain in its action. 
 
 The reader is probably aware that if a vessel be filled with 
 air, no liquid can obtain admittance until a corresponding 
 amount of air be set free. Suppose, for example, that an empty 
 tumbler be inserted over a basin of very clean water, and 
 pressed downwards, it will be found that scarcely any water 
 will enter it, the air having taken up all the available space, 
 and only allowing as much space as may be accounted for by its 
 faculty of compression. 
 
 It is evident, therefore, that if an enlarged tumbler could be 
 lowered to the bed of the sea, a man might be enclosed within 
 it, and for a time be able to support life by means of the air 
 contained within the " bell," as this enlarged tumbler was 
 popularly called. 
 
 It is equally evident that within a short time the air within 
 the bell must be exhausted, and that, unless a fresh supply
 
 DIVING-BELLS. 383 
 
 could be introduced, the diver within the bell would be as 
 effectively drowned as if there were no bell at all. 
 
 The accompanying illustration is a kind of chart, so to speak, 
 of the mode in which air was formerly supplied to the bell. 
 
 On the right hand is seen a section of the Diving-bell itself, 
 together with the seat on which the divers can rest. There is 
 also an escape-valve at the top of the bell, by which the vitiated 
 air can pass away ; but, as it is not essential to the subject in 
 hand, and is rather complicated in structure, it has been 
 omitted. 
 
 Immediately on the left of the bell is a cask, to which 
 several heavy weights are attached. This cask contained com- 
 
 NE8T OF WATER-SPIDERS. DIVlKCi-BELL. 
 
 pressed air, and, after it was lowered by the side of the bell, 
 the end of the flexible tube was taken into the bell, the tap 
 turned, and the compressed air rushed into the bell, taking the 
 place of that which had been exhausted by respiration, and was 
 allowed to pass through the escape-valve. I may mention 
 that the divers unexpectedly discovered that, when they were 
 breathing compressed air, they could dispense with respiration 
 for a wonderfully long time, the amount of oxygen taken in at 
 a single breath being enough to renovate the blood more than 
 could be done by several ordinary inspirations. 
 
 ON the left hand of the illustration is seen a sketch of the 
 nest of the now familiar Water-spider (Argyronetra aquatica)^ 
 taken from some specimens in my possession.
 
 38 1 NATURE'S TEACHINGS. 
 
 The Water-spider is really a remarkable being. Itself a 
 denizen of air, breathing our earthly atmosphere just as we do, 
 and as capable of being drowned as ourselves, it nevertheless 
 passes nearly the whole of its existence under water, and in that 
 strange locality lays its eggs and rears its young. How this 
 wonderful feat is performed we shall now see. 
 
 When the female Water-spider wishes to deposit her eggs, 
 she looks out for a suitable locality, and, being a good diver, 
 tests the various aquatic herbage until she has found a favour- 
 able spot, and then sets to work on her remarkable nest, which 
 I believe is quite original in zoology. 
 
 After stretching a few stout threads by way of a scaffolding, 
 she attaches to the plant a small silken cell, shaped very much 
 like an acorn, but not so large. Ascending to the surface of the 
 water, she contrives to clasp a bubble of air between her last 
 pair of legs, and, laden with this airy treasure, dives below. 
 
 As soon as she has reached the entrance to the cell, which is 
 always below, she loosens her hold of the air-bubble. It at once 
 rises into the cell, and expels a proportionate amount of water. 
 Not many of these journeys are required before the nest is 
 filled with air, and then the diminutive architect spends the 
 greater part of its time in holding on to the mouth of the little 
 diving-bell, and supporting life by means of the air within it. 
 
 This nest, as the reader will see, is an exact representation 
 of the various diving schemes in which air-bells are the chief 
 portions of the machinery, although the air is conducted into 
 them after a different fashion. 
 
 WE now come to another mode of diving, in which the bell 
 is practically superseded by the flexible tube, which allows to 
 the diver far more range than can be obtained by the bell. In 
 this case the diver wears a peculiar dress, the chief part of 
 which is a helmet so constructed that air can be introduced to it 
 from above the surface of the water, and, after respiration, can 
 escape by means of a valve. 
 
 Air is pumped into the tube by assistants above water, and, 
 as the tube is long and elastic, the diver can move about with 
 considerable freedom. As is the case with the diving-bell, the 
 diver's tube is strengthened by an internal spiral wire, so that 
 it is always open, however it may be bent or twisted.
 
 THE RAT-TAILED MAGGOT. 
 
 385 
 
 The right-hand figure of the illustration represents tne diver 
 examining part of a sunken vessel. The tube through which lie 
 breathes is seen passing to the surface of the water, and so is 
 the line by which he gives his signals to his comrades above. 
 In his hand he holds a lamp which can burn for a limited time, 
 being connected by a smaller but similarly constructed tube to 
 a vessel of compressed air. 
 
 ON the left hand of the same illustration are shown the 
 curious Bat-tail Maggots, as they are popularly called. They 
 
 BAT-TAILED MAGGOTS. 
 
 DIVEB WITH AIB-TPBE. 
 
 are the larvse of the common Drone-fly (Eristalis tenax), which 
 is so common towards the end of summer, and looks so curiously 
 like a bee. 
 
 These creatures pass their larval life buried in the mud and 
 below the surface of the water, and yet are obliged to breathe 
 atmospheric air. This they do by means of the long appendages 
 which have gained for them the name of Rat-tails. These 
 " tails" are very elastic, and are capable of elongation and con- 
 traction to a wonderful extent. 
 
 "When the creature is undisturbed, it lies buried in the mud 
 with its head downwards, and its tail extended so that it 
 reaches the surface of the water. Within this tail are two air- 
 tubes, which are connected with the principal tracheae, which 
 
 c c
 
 386 NATURE'S TEACHINGS. 
 
 have already been mentioned. They are wonderfully elastic, 
 and, when the tail is extended to its utmost limit, are nearly 
 straight. When, however, the tail is contracted, the tubes 
 become self-coiled by their own elasticity, and shrink into the 
 base of the tail. 
 
 As the tail is very transparent, it is easy to see how thest 
 movements are conducted. The larvae, which may be found in 
 almost any stagnant water, should be placed in a tall and narrow 
 glass. Some mud should be placed at the bottom of the glass, 
 which should then be filled with water to the depth of three 
 inches or so. 
 
 When the mud has quite subsided, and the water become 
 clear, the long slender tails of the larvae will be seen so elon- 
 gated that their tips reach just above the surface of the water. 
 A. magnifying-glass will easily show the two tubes within the 
 tail. 
 
 Let the glass be but slightly tapped, and all the tail is with- 
 drawn in a moment, so as to be out of reach of external danger. 
 The magnifying-glass will then show the two tubes lying con- 
 tracted in the base of the tail, and taking astonishingly little 
 space, considering the amount of elongation which they can 
 sustain. And, on examining the various bends and curves of 
 the tubes, the value and power of the spiral spring will at once 
 be seen. True, they are very small, but in Nature all things 
 go by comparison, and our whole earth itself is as a grain of 
 sand upon the seashore among the grandeurs of the visible 
 vmiverse. 
 
 THE LEAPING SPRING. 
 
 THE last of the springs which can be mentioned in this work 
 are those which are used for leaping purposes. 
 
 The figure on the right hand represents the common Spring- 
 jack or Skip -jack with which children are always so much 
 amused. It consists of a flattened piece of wood called the 
 "tongue," which is inserted into a twisted string, so that it 
 forms a tolerably powerful spring. When twisted round, and 
 then suddenly released, it strikes against the ground with such 
 force that the whole machine is thrown into the air. 
 
 Sometimes the Skip-jack is made of a fowl's merrythought, as
 
 SKIP-JACKS. 387 
 
 shown in the illustration ; sometimes of the breast-bone of a 
 goose ; and sometimes of a piece of wood cut into the semblance 
 of a frog, and painted. In all cases, however, the machinery is 
 practically the same. I may mention en passant that these frog 
 Skip-jacks are most acceptable presents to savage chiefs in 
 many parts of the world, and that the most powerful and 
 venerable warriors are as delighted with these toys as any 
 European child of six years old. 
 
 Now we will turn to Nature, and see what she has in the 
 way of Skip-jacks. 
 
 All entomologists will at once have before their minds the 
 vast groups of Skip-jack Beetles, technically termed Elateridce, 
 and also known as Click-beetles, from the sharp clicking 
 
 SKIP-JACK BEETLE. 
 
 GRASSHOPPER. 
 
 sound which they produce when in the execution of their 
 curious gymnastics. To this group belong the fire-flies of 
 warm countries, and it may be mentioned that the larvse of 
 some of our species are too familiar to the agriculturist under 
 the name " wireworm." 
 
 All these beetles have very short legs and very long bodies, 
 so that if they should fall on their backs on a smooth surface, 
 they could not recover themselves. Now, as they, when dis- 
 covered, instinctively try to save themselves by falling to the 
 ground, it is evident that some means must be used to enable 
 them to regain their position. This is found in a most curious 
 apparatus. 
 
 Attached to the " prothorax " is a rather long, pointed, and 
 .very elastic projection exactly corresponding with the tongue 
 
 cc 2
 
 388 NATURE'S TEACHINGS. 
 
 of the Skip-jack. The end of this tongue fits into a groove in 
 the " sternum." 
 
 When the beetle falls on its back, it curves its body as shown 
 in the illustration, the tongue thus being freed from its groove. 
 It then smartly springs the tongue back into its place with the 
 sharp clicking sound already referred to, and does so with 
 such force that it leaps into the air to some height. 
 
 Generally it falls on its feet, but if it should fail, it repeats 
 the process. If one of these beetles be laid on a plate or 
 similar smooth surface, it will skip ten or twelve times without 
 stopping, and after a short rest will begin again. 
 
 THERE are some curious little beings, popularly called 
 Spring-tails, which afford excellent examples of the Leaping 
 Spring. Their exact place in the system of Nature is rather 
 uncertain, some zoologists considering them as insects, while 
 strict entomologists reject them. They are very small, and 
 mostly of a darkish brown colour. 
 
 Plenty of them may be found under stones in damp spots, 
 under bark, and in similar localities, though they are often 
 found in houses, and have frequently traversed the paper on 
 which I have been writing this book. Cellars are favourite 
 localities of theirs, and a little flour sprinkled on a plate or 
 piece of paper in a cellar is tolerably sure to attract them. 
 Although they are certainly not more than the fifteenth of an 
 ^nch in length, they may be at once recognised by their 
 peculiar attitude, which very much resembles that of a dog or 
 cat in its usual sitting posture. 
 
 As long as they are not disturbed they crawl about in a 
 quiet manner, but if touched, or even alarmed, they suddenly 
 make a tremendous leap, propelling themselves by means of a 
 forked and elastic tail, doubled under their bodies, and acting 
 just like the tongue of a Skip-jack. 
 
 BELOW the Skip-jack Beetle is shown the common Grass- 
 hopper, as an example of muscular leaping springs. 
 
 We all know what wonderful leaps the Grasshopper, Cricket, 
 and all their kin can make, the leaping movement being 
 evidently intended more as a means of defence than as an 
 ordinary mode of locomotion. The same may be observed in
 
 LEAPING. 389 
 
 the Kangaroos and Gerboas, which are content to use an 
 ordinary walking pace when undisturbed, but when alarmed 
 can make tremendous leaps, and outstrip almost any pursuer. 
 
 Even in Man, the Horse, the Dog, &c., which are most essen- 
 tially leaping animals, the same principle is employed, the legs 
 being used as muscular springs acted upon by the will of 
 the owner.
 
 USEFUL AETS. 
 
 CHAPTER VII. 
 
 FOOD AND COMFORT. 
 
 Parents and their Young. Milk, and the various Ways of obtaining and using it. 
 The Kafir Tribes and Clotted Milk. The Tonga Islanders. The Tartars. 
 Ants and Aphides. Honey -dew. Milch Cows in Insect-land. Fish-tanks 
 and Aquaria. Bill of the Pelican. Eggs and Chickens. The Hen-coop. 
 Nest of Termite. Workers and Queen. Egg-hatching. The Hen and her 
 Young. Artificial Egg-hatching Machine. The Snake and her Eggs. 
 The Gad-fly and Bot-fly. Preservation of Provisions. Hanging Meat. 
 Eggs of the Lace-wing Fly. Spider-eggs. The Butcher's Hook and the 
 Claws of the Sloth. Bats and Insects. 
 
 subject is necessarily a very large one, and I shall, in 
 consequence, be obliged to compress it, though it might 
 well make a separate work by itself. For Food represents the 
 very existence of Man, considered as one of the animal world ; 
 and Comfort represents the progress of civilisation, by which 
 man leaves day by day his savage and solitary nature behind 
 him, and becomes social, moral, and elevated. 
 
 POTTING aside the instinct which forces the parent to feed 
 the young without external assistance, we come to those cases 
 where the parent has to seek food which the offspring could 
 not have found for itself, and often to prepare it for the use of 
 the offspring. 
 
 In the greater part of the world, the milk of various animals 
 is the staple of food, not only for children, but adults ; and the 
 " rm'Tk diet," as it is called, is strongly urged by many phy- 
 sicians of the present day. 
 
 The Kafir tribes, for example, a wonderfully powerful race 
 of men, live almost wholly on sour milk, mixed with maize 
 flour, never eating such valuable animals as kine except on
 
 MILK. 391 
 
 great occasions. Yet the natives of the Tonga Islands think 
 that nothing can be more disgusting than for a human being 
 to drink the milk of a cow. 
 
 How the operation of milking is conducted we need not say, 
 whether it be performed on the cow as with most nations, or 
 the ass in case of need with ourselves, or the mare as with 
 the Tartars, or the goat and sheep in various parts of the 
 world. The milk of the sheep, by the way, is singularly rich 
 and nourishing. 
 
 Suffice it to say that the animals which are to be milked are 
 kept for that purpose, and that the touch of the human hand, 
 rightly applied, induces the animal to part with its milky stores. 
 
 IN Nature there is an exact parallel. 
 
 It has long been known that some species of Ants are in 
 
 ANT AND APHIS- MILKING COW. 
 
 the habit of acting in exactly the same manner as ourselves, in 
 not only extracting a nutritious liquid from other insects, but 
 watching and tending those which furnish their daily food just 
 as a good dairyman watches and tends his cows. 
 
 The Ants, being insects, would naturally require insect cows, 
 and such are to be found in the Aphides, of which mention has 
 already been made. These insects are furnished with a pair of 
 very small tubercles near the end of the abdomen, and from 
 them flows that sweet liquid which is so familiar to us under 
 the name of " honey-dew." For centuries no one knew the 
 source of the sweet honey-dew which attracted all the bees of 
 the neighbourhood to the tree on whose leaves it was sprinkled, 
 sometimes in patches, and sometimes coating them with a thin 
 shining coat, as if varnished. 
 
 At last it- was discovered that the honey-dew is, in fact, the
 
 392 
 
 NATURE S TEACHINGS. 
 
 liquid exudations from these tubercles upon the backs of the 
 aphides, and that the ants feed regularly upon it. Not only do 
 they lick up the honey-dew that has fallen from the ants, but they 
 milk them, so to speak, exactly as a dairymaid milks a cow. 
 With their antennae the ants pat and stroke the tubercles of 
 the aphides, and in a few seconds a drop of pellucid liquid 
 appears at the extremity. This is the honey-dew, and is at 
 once lapped up by the ant, which proceeds from one aphis to 
 another until it has obtained its fill of the sweet food. 
 
 How the ants carry off the aphides, cherish and guard them 
 for the sake of their honey-dew, is a story too long to be told, 
 but it is well known among entomologists. Our English ants 
 are, however, totally eclipsed by a Mexican species, which not 
 only collects honey, but stores it in the bodies of its kindred- 
 
 After taking precautions that no food can escape, the ants feed 
 with their sweet store their companion, who is thus doomed to 
 pass the remainder of life as a mere honey-cell. The abdomen 
 becomes spherical, smooth, and so transparent that the honey 
 can be seen within it. It is quite air-tight, and so preserves 
 the fragrance of the honey until it is wanted. 
 
 So plentiful are these honey-ants, that they are an article of 
 commerce, and are sold by measure for the purpose of making 
 a sort of mead. There are many of them in the British 
 Museum, with the honey still within their transparent bodies, 
 and they are well worth seeing. 
 
 THE accompanying illustration represents the artificial and 
 natural way of preserving food in an uninjured state. The
 
 THE FISH-TANK. 393 
 
 right-hand figure is that of an ordinary glass aquarium, such 
 as was in general use until the properties of air and water were 
 better understood, and it still need not be rejected. It is 
 simply a vessel in which water is contained, so that aquatic or 
 marine animals may be able to live in it for some time. 
 
 There are infinite varieties of the " Fish-tank," if we may 
 so call it, the chief of which is the " well," which is so exten- 
 sively used in bringing fish to market. 
 
 Through the bottom of the boat projects a sort of box pierced 
 with holes, so that the water has free access and egress. The 
 sides of the box are so high that there is no fear of the water 
 rising into the boat. When fish are taken, they are thrown 
 into the well, and there can live until they are wanted for sale. 
 
 Also, as all know who are acquainted with river-banks or 
 seashores, fishermen have similar wells detached from the 
 boats, and partly or entirely sunk in the water. In them they 
 keep their stock, and, when a customer arrives, they simply 
 draw the box ashore, so that the water runs out, select what 
 fish they choose, and replace the box in the water. 
 
 Now, the power of conveying fish to some distance without 
 destroying life has for countless ages been possessed by the 
 Pelican, one of which birds is shown in the accompanying 
 illustration. 
 
 As every one knows, the chief peculiarity of this bird is the 
 large and very elastic membrane of the lower jaw. When not 
 in use, it contracts by its own elasticity, and the bill looks 
 quite slender, as well as long. But, when distended with 
 water and fish, it presents the appearance shown in the illus- 
 tration. 
 
 Any one who wishes to see the exercise of this power can 
 do so by attending the Zoological Gardens, and visiting the 
 Pelicans at feeding-time, and an hour or two before it. They 
 hardly seem to be the same birds. Some years ago I made a 
 series of sketches of the same Pelican under different circum- 
 stances, and it is scarcely possible to believe that they could 
 be, as they are, truthful representations of the same bird. 
 
 THE right-hand figure of the next illustration requires no 
 comment, as it simply represents the ordinary hen-coop.
 
 394 
 
 NATURE S TEACHHS 7 GS. 
 
 As everybody is aware, the object of the coop is to keep the 
 hen within its bars, while the little chicks can run in and out 
 as they choose, and the coop is made so as to prevent the egress 
 of the mother, while the offspring find no difficulty in 
 escaping. 
 
 Now, in the world of insects we find an exactly analogous 
 structure. As is the case with many hymenopterous insects, 
 there is in the nest of the Termite, or White Ant, as it is 
 popularly called, a single perfect female, which is the mother of 
 the nest. A similar arrangement occurs in the common hive- 
 bee, but there is a notable distinction between the queen Bee 
 
 QUEEN TERMITE IN HER CELL. 
 
 HBN IN HER COOP. 
 
 and the queen Termite, the latter belonging to the neuropterous 
 order. 
 
 The former is unconfined, and moves about from cell to cell, 
 depositing her eggs within them, and taking the greatest pains 
 that they occupy exactly their proper place within the cell. The 
 latter never moves after she has begun to deposit eggs, but 
 remains motionless in the same spot, and allows her subordi- 
 nates to dispose of the eggs which she lays. 
 
 How this end is achieved will now be seen. 
 
 The reader is probably aware that the queen Termite attains 
 to enormous dimensions, her head, thorax, and legs retaining 
 their normal size, but the abdomen becoming several inches in 
 length, and thick in proportion. The legs are necessarily 
 unable to move so vast a body, and in order that so important 
 a personage should not receive injury, a large oval cell is built 
 around her, from which she never moves for the rest of her 
 life. She has but one duty, namely, to lay eggs, and so is fed
 
 EGG-HATCHING. 
 
 395 
 
 that she may have strength to produce tnem. She is simply 
 passive, and never even sees her eggs, much less has care of 
 her young. 
 
 All the care of guarding and nurturing the eggs and young 
 falls upon the worker Termites. These insects are quite small, 
 about the size of our common Wood-ant. 
 
 When they build the clay cell around their queen, they bore 
 a number of holes along the sides, which are just large enough 
 to allow the workers to pass freely, but which effectually exclude 
 the soldier Termites, or any foes larger than themselves. 
 
 Through these apertures streams of workers are continually 
 passing some entering the cell to fetch the eggs, and others 
 coming out with eggs carried carefully in their jaws. 
 
 1 WDRBL*6" OF (ISTRUS. 
 
 EGG-HATCHING MACHIKK. 
 
 Thus, as the reader will see, we have in Nature an exact 
 analogy of Art, the Termite queen being confined within her 
 cell exactly as is the hen within the coop. 
 
 BEING on the subject of eggs and egg-hatching, we will 
 take another case in which Art has acknowledgedly followed 
 Nature. 
 
 We all know that eggs are developed into life by means of 
 well-regulated heat, and that with birds the general rule is, 
 that the needful heat is supplied by the parent bird, who sits 
 upon them for a certain time, until the young birds make their 
 appearance in the world. 
 
 Under ordinary circumstances, the aid of the parent bird is
 
 396 NATURE'S TEACHINGS. 
 
 quite sufficient ; but when the progress of civilisation requires 
 that the eggs of poultry should be hatched in numbers too 
 great for the powers of the parent bird, Man has been fain to 
 imitate Nature, and to invent machines whereby eggs can be 
 hatched by artificial heat, regulated to the temperature of the 
 hen's body. 
 
 Various as are these machines in detail, they are all alike in 
 principle, and the right-hand figure of the accompanying illus- 
 tration will give a fair idea of the method which is employed. 
 
 A box is fitted up with trays, on which the eggs are 
 arranged. At the bottom of the box there is the heat- 
 producing apparatus, which can be regulated at pleasure. The 
 trays of eggs can be moved from one part of the box to 
 another, so as to insure the right amount of heat, and, if this 
 process be only carefully carried out, the young chicks emerge 
 from the eggs exactly as they would have done if the hen had 
 sat upon them. 
 
 This machine is sometimes called the Artificial Mother, and 
 it is worthy of notice that it is no modern invention, the ancient 
 Egyptians having used it more than three thousand years ago. 
 
 WITH regard to Nature, it would have been simple enough 
 to give one illustration of a bird sitting on her eggs, but I 
 have preferred to select a different subject, as more relevant to 
 the question of artificial heat. 
 
 There is an insect to which we have had several occasions of 
 reference, namely, the Wurble-fly of the ox, scientifically 
 known as (Estrus bovis. 
 
 The eggs of this insect are deposited in the skin of the ox, 
 and are there hatched by the heat of the animal. In propor- 
 tion as the larva grows, it raises lumps upon the skin, these 
 being practically the roofs of the artificial home. There are 
 several other species of the same genus, all of which have their 
 eggs hatched by the heat of the animals on which they are 
 placed. There are, for example, the common Bot-fly (CEstrus 
 egui), whose eggs are hatched in the interior of the horse, 
 and the Sheep- fly (CEstrus ovis), whose eggs are hatched in the 
 head of the sheep. The common Snake leaves her eggs to be 
 hatched in the artificial heat produced by decaying vegetable 
 matter.
 
 PRESERVATION OF PROVISIONS. 
 
 397 
 
 WE now come to the preservation of provisions. 
 
 In the first place, we have the well-known " cache " of 
 Northern America i.e. a spot wherein provisions are hidden, 
 and their locality only marked by signs intelligible to those for 
 whose use they are intended. It is, perhaps, hardly necessary 
 to mention that many creatures such as the dog, the squirrel, 
 and most of the crow tribe are in the habit of concealing pro- 
 visions for future use. 
 
 In those parts of the world, however, where the rights of 
 hunters are acknowledged, any one who kills a deer, or other 
 animal of chase, and is not able to carry off the entire body, 
 can preserve it for his own use. He simply cuts it up in 
 hunter fashion, and hangs the various portions to branches of 
 
 8PIDEB-NESTS. EGOS OF 
 
 LACE-WING FLY. 
 
 SPIDER-NEST. 
 
 PROVISIONS HUNG TO TREE BRANCH. 
 
 trees, where they are out of the reach of wild beasts. Stores 
 like these, such as are shown in the illustration, are always 
 respected, and no hunter would dream of helping himself to 
 the game which was killed and dressed by another. 
 
 Beasts of prey, however, cannot be expected to be so punc- 
 tilious, and in consequence the hunters hang their meat to 
 branches which cannot be reached. 
 
 IN Nature we find many similar examples, one or two of 
 which are given on the left hand of the illustration. 
 
 In the centre is seen a group of eggs of the Lace-wing Fly 
 (Hemerobius) , so called on account of the delicate, lace-like 
 structure of its beautiful pale green wings. 
 
 When the female lays her eggs she always chooses a slight
 
 398 NATURE'S TEACHINGS. 
 
 twig, and upon it deposits a little drop of a slimy consistence. 
 She then draws out this drop into a thread, which hardens as it 
 is brought into contact with the air. At the extreme end of 
 the thread she places an egg, which is thus kept at some height 
 above the ground, and defies the approach of inimical insects. 
 The eggs, as well as the stalks, are perfectly white, and have 
 so singular a resemblance to mosses, that for many years they 
 were actually classed and figured as such. 
 
 These egg-groups are plentiful enough, if the observer only 
 knows where to look for them. I have several of them in my 
 collection, and have found that nearly every one who sees them 
 for the first time takes them for mosses. I never myself saw 
 the pretty insect lay its eggs, and for the description am 
 indebted to Mr. A. GK Butler, of the British Museum, who has 
 kept them and watched their habits. 
 
 The objects on either side of the Lace-wing Fly's eggs are 
 egg-groups of certain spiders, suspended by threads from 
 branches. 
 
 
 
 A STILL more remarkable instance of unconscious imitation 
 may be found in the two objects in the accompanying illustra- 
 tion. It is hardly necessary to say that the right-hand figure 
 represents a portion of the arrangement by whwh a butcher 
 hangs up his meat out of harm's way until it is wanted. 
 
 The hooks in question are simply formed into a double curve, 
 like the letter S, and can be slid along the horizontal bar with- 
 out any danger of falling. 
 
 Now, in the common Sloth we have an exact prototype of 
 the butcher's hook. The Sloth passes the whole of its life in 
 the remarkable attitude which is shown in the illustration. 
 It lives among the branches not on them, but under them 
 its claws being long and curved, just like a butcher's hook. 
 I have often watched the animal traversing the branches, and 
 have been greatly struck with the accurately picturesque 
 description of the late Mr. Waterton, who was the first to dis- 
 cover the real character of the Sloth. 
 
 It was he who found out that the previous ideas as to the 
 Sloth's mode of life "were utterly erroneous, and that, instead of 
 being a sort of bungle, the Sloth was as perfect in its way, and 
 as well fitted for its mode of life, as the lion or tiger. He dis-
 
 HOOKS AND CLAWS. 
 
 399 
 
 covered that the animal always hung from the branches, as 
 shown in the illustration. In fact, as Sydney Smith remarked 
 in his witty review of "Waterton's Wanderings," the Sloth 
 
 BUTCHERS' HOOKS. 
 
 passes his whole life in suspense, 
 tantly related to a bishop." 
 
 : like a young clergyman dis- 
 
 THERE are many other creatures which afford similar 
 examples, though perhaps none are so striking as the Sloth. 
 
 For instance, there are the whole tribe of Bats, which, by 
 means of the curved claws attached to their hind- feet, can hang 
 themselves head downwards in the open air, and even swing in 
 wind, without the least fear of falling.
 
 USEFUL ARTS. 
 
 CHAPTER VIH. 
 
 DOMESTIC COMFORT. 
 
 How to make Home comfortable. The Bed in its various Forms. The Feather 
 Bed of Man. The Eider-duck and her Plumage. The Rabbit and her 
 Down. The Long-tailed Titmouse and her wonderful Nest. The Hammock 
 of civilised Man and Savage. The Sailor's Canvas Hammock. The String 
 Hammock of tropical America. Nest of the Pensile Oriole. Silken Ham- 
 mock of the Tiger-moth and other Insects. The Mat Bed. Cocoa-nut 
 Matting. The Robber-crab and its Bed. Strength and Uses of the Cocoa- 
 nut Fibre. The Surgeon's " Cradle" and the Pupa of Tabanus. The Art 
 of Sewing and the Tailor-bird. Principle of the Umbrella and its Original 
 Use. Natural Umbrella on the Rosemary. Servants and Slaves, and the 
 Distinction between them. The Use of Slaves in hot Countries. Slavery in 
 the Insect World. The Ants and their Slaves. Ornamental Gardening and 
 Pleasure-grounds. The Hanging Gardens of Babylon. The Bower-birds 
 and their Pleasure-grounds. 
 
 TTTE now come to a different branch of the same subject, 
 * * namely, the means by which our dwellings are rendered 
 comfortable. 
 
 After having procured a dwelling which can withstand the 
 elements, we next look for a bed on which to repose, and 
 which will ease the limbs and brain, wearied by the toils of 
 the day. 
 
 Allusion has already been made to the ordinary feather bed 
 and its multitudinous natural springs. We now have to see 
 how the various kinds of beds are anticipated in Nature, and 
 will begin with the feather bed. 
 
 As to our own beds, nothing need be said about objects so 
 familiar, although, in order to preserve the parallelism, it is 
 necessary to introduce an illustration on the right hand of the 
 page. 
 
 On the left hand are shown two examples of natural feather
 
 FEATHER BEDS. 
 
 401 
 
 beds, selected from many others on account of the exact parallels 
 which they afford. 
 
 "We all know the wonderful warmth and lightness of the 
 Eider-down mattress or quilt, though there are comparatively 
 few who know how the Eider-down is procured. 
 
 In common with many other creatures, the Eider-duck forms 
 a bed for her young by plucking the down from her own body. 
 Rabbits do exactly the same thing, as all boys know who have 
 kept them, the only difference being that fur is substituted for 
 feathers. So do many insects, stripping themselves of their 
 
 LONG-TAILED TITMOUSE. 
 
 EIDEB-DUCK. 
 
 FEATHER BED. 
 
 own downy covering, and employing it for the comfort of their 
 offspring. 
 
 The lower figure on the left hand represents the Eider- 
 duck in the act of plucking the far-famed down from her 
 breast in order to make a soft and warm couch for her young, 
 and the amount of feathers which she will devote to this 
 purpose is simply astonishing. Their weight is insignificant, 
 but their bulk is wonderful. 
 
 Above the Eider-duck is shown the nest of the common 
 Long-tailed Titmouse. It is the most perfect nest that is 
 constructed by any British bird. Its shape exactly resembles 
 that of an egg, and it has but one small aperture, as is shown 
 in the illustration. 
 
 The Titmouse lays a vast number of eggs, and almost fills 
 
 D D
 
 402 NATURE'S TEACHINGS. 
 
 the nest with soft downy feathers, on which they can rest. 
 If the finger be introduced into the nest through the aperture, 
 the tiny eggs can be felt reposing in their natural feather-bed. 
 In this case, however, the bird does not denude herself of 
 feathers, but has a way of picking them up wherever she can 
 find them. 
 
 Now we will take another form of bed, namely, the Hammock, 
 which is used in many parts of the world. 
 
 Putting aside the well-known hammock as used on board 
 our ships, we will take the same kind of bed as used among 
 the natives of tropical America. 
 
 In that wonderful part of the world, where water and 
 vegetation reign supreme, an aerial couch of some kind is 
 absolutely needful, and is supplied by the singularly ingenious 
 hammocks which are constructed by the natives. They are 
 made of a fine, but marvellously strong fibre, procured from 
 the aloe plant by the simple process of soaking the long leaves 
 in water, and dashing them against a stone. The soft green 
 parts are eaten away, and the tough fibres remain in all their 
 strength. 
 
 From these fibres are woven the strings of which the 
 Hammocks are made. I possess four of the Hammocks, all 
 made on different lines, but all based on the same principle. 
 In some the strings are laid parallel to each other, and con- 
 nected by transverse strings at regular intervals, but in the 
 best specimens they are interlaced diagonally into a sort of 
 loose network without knots, so that it yields in every direction 
 to the outlines of the body. 
 
 It is one of the most comfortable couches ever invented, 
 especially when it is of considerable size. I have one specimen 
 which, even in its curved state, extends completely across a 
 tolerably sized room. I never use it because it is so comfortable 
 that the temptation to lie in it is almost too strong to be 
 resisted. 
 
 As to Hammocks in Nature, they are almost too many to 
 be computed. 
 
 So we will first take the nest of the Pensile Oriole, which is 
 shown in the illustration, and which is an admirable example
 
 THE HAMMOCK. 
 
 403 
 
 of the Hammock, being woven from long vegetable fibres 
 intertwisted very much like the strings of the South American 
 Hammock. And as if to increase the resemblance, the bird, 
 whenever it can do so, will carry off hanks of cotton, linen, 
 thread, or pieces of string, and weave them into its nest. 
 
 I have one of these nests, and, directly I saw it, was struck 
 with its exact similitude to the Hammock of human manu- 
 facture. 
 
 There are many other birds in various parts of the world 
 
 NK8T OV PENSILE ORIOLE. 
 
 especially in Australia, which make their nests on exactly the 
 same principle, though in slightly varied forms. 
 
 Also, in the insect world, there are innumerable examples of 
 the natural Hammock, the most common of which is that made 
 by the caterpillars of the Tiger-moth, and in which it slings 
 itself while undergoing its changes from the chrysalis to the 
 perfect state. 
 
 It is made of silken threads, interwoven so slightly that the 
 chrysalis can be seen through them, and so exactly like the 
 Hammock of the South American Indian that if a drawing 
 were made and enlarged, one might easily be taken for the 
 other. 
 
 Now we come to the Mat Bed, which is so much used in the 
 warmer parts of the world, where the earth is dry, and the air 
 so warm that nothing is required but the slightest possible 
 protection from the soil. 
 
 In inland places, such as Southern Africa, the bed is made 
 of long grass-stems laid side by side, and sewn together with a 
 
 r> D 2
 
 404 NATURE'S TEACHINGS. 
 
 sort of twine. One of these beds in my collection is some three 
 feet wide by seven feet long, and can be rolled up into a cylin- 
 der so compact and light that even a child could carry it. 
 
 Of course, when the Kafirs are on a journey, the women have 
 to carry the beds, together with the heavy wooden pillows and 
 other necessaries, the men carrying nothing but their weapons. 
 I have a pair of figures made by a native artist, representing a 
 
 1.0BBER-CRAB. COCOA-NUT MAT. 
 
 Kafir man and woman on a journey, the woman staggering 
 under her heavy burdens, the bed being included, and the man 
 stepping lightly along, with nothing but his spears and knob- 
 kerries. 
 
 ON the sea-coasts, however, where the cocoa-nut palm 
 grows, the fibre of the husk is the principal material for bed- 
 ding. These fibres lie so parallel to each other on the surface of 
 the cocoa-nut, that they are easily stripped off, fastened together, 
 and formed into mats of any shape or thickness. One of these 
 mats is shown on the right hand of the illustration, and the 
 reader will see how simple is its manufacture. 
 
 Owing to the ease with which it is made into a fabric, the 
 cocoa-nut fibre was in great use as armour before the bullet set 
 all armour at defiance. It will be remembered that when Cap- 
 tain Cook was murdered, he committed the mistake of firing a 
 charge of small shot instead of a bullet, and the fact that 
 the cocoa-nut mat carried by the man at whom he fired 
 resisted the shot, encouraged the natives to attack and murder 
 him.
 
 COCOA-NUT MAT. 405 
 
 EVEN the cocoa-nut mat has its precursor in Nature. 
 
 There is a certain Crab inhabiting the cocoa-nut bearing 
 parts of the world, which not only makes itself a bed from the 
 fibre, but supplies it to mankind. 
 
 This wonderful Crab has the power of ascending the cocoa- 
 nut palms, which is beyond the power of any man except a 
 trained gymnast. It picks out the ripest fruits, and with its 
 powerful claws tears off the fibre before breaking the shell and 
 devouring the kernel, as is shown in the left-hand figure of the 
 illustration. 
 
 After eating the kernel, which is at that time a soft, creamy 
 substance, quite unlike the hard, indigestible material which we 
 in England know by the name of cocoa-nut, the Crab carries 
 off the external fibres into its den, and there makes its bed of 
 them. So great, indeed, is the amount of cocoa-nut fibre thus 
 collected that the natives are accustomed to save themselves 
 the trouble of climbing the trees, and merely search for the 
 holes in which these Crabs have made their nests, knowing the 
 amount of ready-gathered cocoa-nut fibre that is always to be 
 found in them. 
 
 ANOTHER modification of the bed needs a short notice, espe- 
 cially as I have practical and sad experience on the subject. 
 
 PUPA OF TABANUS. 8UBGICAL CRADLE. 
 
 It is technically named the " cradle," and is used to keep the 
 bedclothes from pressing on a damaged limb. 
 
 When a mere lad I contrived, at cricket, to dislocate the 
 right ankle, and break the bone. An ignorant surgeon refused 
 my request for a cradle, and absolutely tied the cover of a book 
 to the sole of the foot. Of course this appliance was worse 
 than useless. It acted as a lever, allowing the clothes to turn 
 the foot round, and to the present day the right foot has never 
 recovered its faculties. Had the simple " cradle " been used
 
 406 NATURE'S TEACHINGS. 
 
 i.e. a few sticks bent into an arch-like shape, and tied together, 
 so as to keep the clothes from even touching the foot all 
 would have been right. 
 
 On the right hand of the illustration is shown the surgical 
 cradle, as a defence to a damaged leg. On the left is shown 
 the curious natural cradle of the Gad-fly while undergoing its 
 change into the perfect state. It is quite hard and rounded, 
 being formed from the skin of the larva, and allows the pupa 
 to lie within it, protected from any ordinary pressure. 
 
 ANOTHER point now comes before us. 
 
 We cannot well have our bedclothes indeed, any kind of 
 clothes without the use of needles and thread. The simplest 
 form of sewing is that which is adopted in many parts of the 
 world, namely, of boring holes and pushing a thread through 
 them, no eye being required in the needle. In this way the 
 Kafirs of Southern Africa and the Esquimaux of the Polar 
 regions make their beautiful garments of skins. I have for 
 many years had in constant use two South African cloaks, or 
 karosses, and one made by the natives of Vancouver's Island, 
 and they are now as good as they were when they were first 
 given to me. Naturally, such a mode of sewing consumes 
 much time, but, as time is not of the least value to these native 
 furriers, no harm is done, and the junctions of the different 
 skins is absolutely perfect. Even where holes have been made 
 in the skin, the native furrier has supplied their places with 
 circular pieces so neatly inserted, that on the outside not a 
 trace of the junction is visible, and even the very set of the 
 hairs is preserved. 
 
 Our very modern needles, with their eyes which carry the 
 thread, are but a modification of the original plan of boring 
 holes, and pushing the thread through them. 
 
 NATURE has a singular parallel in the case of the Tailor-bird, 
 which sews leaves together by their edges, and makes its nest 
 inside them. It acts exactly like one of our own shoemakers, 
 using its slender and sharply poinled beak in lieu of the awl, 
 and employing a slight but strong vegetable fibre in place of 
 the "waxed end" of the shoemaker, or the sinew- thread of the 
 Kafir.
 
 SEWING. 
 
 407 
 
 In the illustration an ordinary needle an tnread are seen on 
 the right-hand side, and on the left are two nests of the Tailor- 
 bird, taken from specimens in the British Museum. 
 
 The mode of sewing is strangely like that which is employed 
 by the uncivilised furriers who have been described, and much 
 
 r 
 
 TAILOR-BIRDS AND NESTS. 
 
 SEWINO CLOTH. 
 
 superior to that which is seen in many other parts of the world. 
 For example, I have a West African quiver made of hide sewn 
 together with stitches infinitely more clumsy than those of the 
 Tailor-bird. 
 
 The reader will also remark that I might have placed this 
 singular nest in the category of beds, on account of the soft 
 and warm lining on which the young repose. I have, however, 
 thought that it more properly belongs to the present division of 
 the subject. 
 
 SOMETIMES we require a temporary as well as a permanent 
 shelter from the elements, and procure it by means of the 
 Umbrella. 
 
 In many countries, especially those where the climate is hot, 
 the Umbrella is almost exclusively used, as, indeed, its name 
 denotes, to preserve its owner from the direct sunbeams, and is, 
 in fact, the " parasol " of our European ladies. It also is a mark 
 of dignity, the amount and quality of its decorations indicating 
 rank, even though the man who sits under its shade is clothed 
 in a modest cotton cloth wrapped round his waist. 
 
 For the purpose of shielding the bearer from the sun the 
 Umbrella was first introduced, and the introducer incurred the 
 obloquy usual in such cases. Now, however, the Umbrella has
 
 408 
 
 NATURE'S TEACHINGS. 
 
 by common consent become a defence against rain and snow, 
 the male sex leaving the parasol to the gentler half of creation, 
 and submitting themselves to the chance of a sunstroke. 
 
 WE all know the ingenious Umbrellas of Africa, China, Japan, 
 Siam, &c. ; but there are few persons who know that a common 
 
 HAIRS OP P.OSEMAP.T. 
 
 UMBRELLA. 
 
 magnify ing- glass will disclose thousands of beautifully perfect 
 umbrellas on the leaf of the Rosemary. 
 
 Pinch the Rosemary-leaf between the fingers, and a strong 
 and peculiar perfume is evolved, just as when the peel of the 
 orange is squeezed. The reason is the same in both cases, 
 namely, the presence of multitudes of spherical vessels which 
 contain their essential oil, secreted by the plant. 
 
 In the orange they are sunk below the surface of the skin, 
 and are protected by it ; but in the Rosemary they stand on 
 slight footstalks, as shown in the illustration. 
 
 Being very delicate, and liable to be broken at the least touch, 
 they are protected by a series of curiously formed hairs, which 
 extend over them exactly as would an umbrella, and defend 
 them from the elements. 
 
 The surface of a Rosemary-leaf affords a singularly beautiful 
 sight, even with a common magnify ing- glass, the tiny perfume- 
 globes gleaming like little pearls in the broken lights that shine 
 through the umbrella-like hairs. 
 
 Now we come to another part of domestic life, namely, 
 Servants. 
 
 There is a diversity of ideas on this subject, as we know by
 
 SERVITUDE. 409 
 
 thevarious discussions respecting "lady-helps" and "gentlemen- 
 helps," which bid fair to initiate a revolution in domestic life. 
 Servants are sometimes called the greatest plagues in life, but 
 it is difficult to see what could be done without them. 
 
 Then there is the complaint that servants are not what they 
 used to be the faithful retainers of the household, and con- 
 sidering themselves members of it. Perhaps not, but I have 
 had experience of several faithful retainers, and invariably 
 found them to be unmitigated tyrants, assuming power, repu- 
 diating responsibility, and being practically the master or 
 mistress of the household. 
 
 Then we come to the great question of slavery in its various 
 bearings. 
 
 Putting aside the now acknowledged diversity of races, and 
 the well-known fact that the negro in a state of slavery to a 
 European is infinitely better off" than he would have been in his 
 own country, where there is no law but that of might, we must 
 entertain the question of enforced servitude, i.e. where the 
 servants have no choice either in entering or leaving their 
 situations. 
 
 It is, of course, opposed, and rightly, to our modern English 
 ideas that a slave, under such a name, should exist on British 
 ground. Yet there are thousands of Englishmen who are 
 more wholly enslaved than was any negro in the worst times of 
 slavery. The chains may not be of visible iron, nor the 
 whips of tangible thongs, but they are, perhaps, all the more 
 galling and biting. 
 
 SOME of my readers may be aware that slavery exists in the 
 insect world, and probably existed long before man came on 
 earth. 
 
 There are many species of Ants which are absolutely incapable 
 of managing their own nests or rearing their own young, and 
 which, in consequence, impress into their service the workers of 
 other species of Ant, and hand over to them the entire labour 
 of the establishment. They can fight, and they can establish 
 fresh colonies, but they cannot build nests, nor nurse their 
 young, and so they impress into their service those Ants whose 
 instinct teaches them to do both. 
 
 Periodically the master Ants, if we may so call them, set off
 
 410 
 
 NATURE S TEACHINGS. 
 
 on a slave-hunting expedition. They find out the nest of the 
 special Ant whose aid they need, penetrate into it, and bear off 
 the pupae, or " ants' eggs," as they are popularly called. These 
 are carried to their new home, and are speedily hatched. They 
 know no other home, and, led by instinct, set to work as indus- 
 triously as if they had never been removed. 
 
 Those who have watched their habits are unanimous in 
 declaring that they seem perfectly happy and contented. No 
 
 SLAVE-CAPTUBIXG AXTS. 
 
 compulsion is used towards them, and they work because told 
 to do so by their own instinct. Work they must, and it does 
 not in the least matter to them for whom the work is done. 
 
 ANOTHER branch of this subject is shown in the accompanying 
 illustration, namely, the pleasure garden or playground. 
 
 This is, as we all know, a token of high civilisation, and even 
 in the ancient times the hanging gardens of Babylon were 
 reckoned as the greatest wonders of that great city, the then 
 mistress of the world. 
 
 No savage ever dreamed of such a thing as a pleasure garden, 
 nor could appreciate it if he saw it. Yet there are birds which 
 far surpass the savage in this respect, and which build recrea- 
 tion grounds for the sole purpose of amusement. 
 
 These are the well-known Bower-birds of Australia, which I 
 sincerely hope may not be extirpated by the white man, as has 
 been the case with so many creatures, including the aborigines 
 of Tasmania themselves. 
 
 The Bower -birds, which are distantly related to our thrush
 
 PLEASURE-GROUNDS. 
 
 411 
 
 and blackbird, but are about as large as jackdaws, have a 
 curious habit of building arched bowers quite independent of 
 their nests. 
 
 The shape of one of these bowers is shown in the accompany- 
 ing illustration. 
 
 The bird first weaves a sort of platform of flexible sticks, and 
 then fastens into them a number of other sticks, so set that they 
 form a sort of arched gallery. Through this gallery the birds 
 love to run, and they invariably decorate the ends with any- 
 thing pretty that they can pick up, such as feathers, coloured 
 
 PLAYGROUND OF BOWEE-BIBD. 
 
 CrAitDEN BOWER. 
 
 stones, shells, ornaments, and the like. So well is this proclivity 
 known, that whenever any one who is living in the Bush loses 
 any small piece of property, such as a pencil-case or watch-key, 
 or even a tobacco-pipe, he always goes to the Bower-bird's 
 pleasure garden, and mostly discovers the lost property. 
 
 At the Zoological Gardens these Bower-birds have long lived, 
 and it is a most interesting sight to watch them weaving their 
 platforms, raising the bowers over them, and then keep running 
 in at one end and out at the other, like children at play, and 
 with their burnished plumage gleaming in the sunbeams. 
 
 The right-hand figure simply depicts a modern pleasure 
 garden, and needs no description.
 
 USEFUL ARTS. 
 
 CHAPTER IX. 
 
 ARTIFICIAL WARMTH. RING AND STAPLE. THE FAN. 
 
 Various Modes of warming Houses, The Fire of the American Indian and the 
 Kafir. The Oil-lamp of the Esquimaux. The open Fireplace and 
 Chimney Stoves. The laminated Stove and its Powers. Gills of the 
 Lobster, Crab, and various Fishes. Mode in which the Gills act. Why 
 Fishes lie with their Heads against the Stream. Drowning a Fish. The 
 Ring and Staple, and their various Uses. Head-bones of the Fishing- 
 frog or Angler-fish. The Fan and its Modifications. Japanese and 
 Chinese Fans. The Feather Fan. The Palm-leaf. Indian Fans. 
 The Hive Bee and its Wings. Fans of the Essequibo and South Sea 
 Islanders. The Fan Fire-guard. Antennae of the Cockchafer. Burial. 
 Various Modes of disposing of the Dead. Ordinary Habits of dying 
 Animals. Dead Insects. The Funeral-ant and its wonderful Habits. 
 
 / 
 
 ARTIFICIAL WARMTH. 
 
 T)ASSING- from the direct to the indirect comforts of a house- 
 -*- hold, we will take Artificial "Warmth. 
 
 The savage, as a matter of necessity, makes a fire in the 
 middle of his hut, and lets the smoke have its own way. 
 Sometimes, as is the case with the North American Indians, 
 the top of the conical hut is open, and the whole edifice is a 
 single chimney of large dimensions, something like the 
 " chimney-corner " of past days, which only survives in such 
 places as the New Forest. 
 
 Then there are the various Kafir tribes of Southern Africa. 
 They have no aperture in their huts except the tiny doorway, 
 which can only be entered on hands and knees. But they must 
 have their fire. No argument can persuade them that they had 
 better make their fire and cook their flood outside the hut. So 
 the wood-smoke fills the hut, coats it with a lining of soot, and 
 gets out as it can through the sticks and wishes of which the 
 simple edifice is built.
 
 ARTIFICIAL WARMTH. 
 
 413 
 
 As a contrast, we have the oil-lamp of Esquimaux-land, 
 where there is no provision for ventilation, where the snow- 
 houses are tightly closed and crammed with inhabitants, and 
 where no one seems to need fresh air. 
 
 The next step in civilisation is to construct a tube for the 
 purpose of carrying off the smoke, such as we know by the 
 name of chimney or flue, and to place the fire within it. We 
 English people have an ingrained love for the open fireplace, and 
 though it really is an expensive arrangement, it is worth the cost. 
 Granting that it carries much of the heat into the chimney 
 instead of throwing it into the room, it has at least the advan- 
 tage of acting as a ventilator, of ejecting air which has been 
 rendered poisonous by respiration, and drawing a fresh supply 
 from the outer atmosphere. 
 
 In some parts of the world, especially in Germany and the 
 United States, the place of the open fire is taken by closed 
 stoves, without any ventilation whatever, much to the discom- 
 fiture of ordinary Englishmen. Still, there are buildings, such 
 as public halls and places of worship, in which open fireplaces 
 are wholly impracticable, and where it is, therefore, necessary 
 to make use of the stove. 
 
 It need hardly be said that in such cases the chief object is 
 to procure the greatest amount of heat with the least expendi- 
 
 rtffaft^ 
 
 GILLS OF SHARK. 
 
 GILLS OP TKOUT. 
 
 ture of fuel, and that object seems to be best attained by the 
 Laminated Stove shown on the right hand of the illustration. 
 
 In this stove, the outer surface, instead of being plain, is 
 divided into a number of perpendicular plates, which are heated
 
 414 NATURE'S TEACHINGS. 
 
 by the contained fire, and expose a very large surface of hot 
 metal to the air. Thus the heat, instead of being wasted by 
 being drawn through the flue or chimney, is thrown into the 
 room, and keeps up a perpetual supply of warm air. 
 
 THAT 1he invention of this stove is an ingenious one nobody 
 can deny. But Nature has been long in advance of Art in the 
 way of exposing as large a surface as possible with the least 
 expenditure of space. 
 
 Very familiar examples of this structure may be found in the 
 many creatures which inhabit the waters and breathe by means 
 of gills, which extract the oxygen of the water. 
 
 Take, for example, a Lobster or a Crab, open it, and look at 
 the white, pointed, uneatable objects which are popularly called 
 " ladies' fingers." These are the gills, or breathing apparatus, 
 and their structure is really wonderful. They are composed 
 of innumerable laminae, or very thin plates, covered with an 
 exceedingly fine membrane, and placed closely side by side, 
 but with sufficient distance between them to allow the water 
 to percolate the whole structure. 
 
 With the aid of an ordinary pocket lens the observer may 
 make out a most wonderful system of blood-vessels, which per- 
 meate every one of the myriad laminae, and which extract the 
 life-giving oxygen from the water as it passes between them. 
 
 Then, to pass to animals of a higher order, take the gills 
 of fishes. . Any fish will do, provided that it be fresh, and, if 
 it can be examined immediately after death, so much the better. 
 Taking things reciprocally, the gills of the fish and the laminae 
 of the stove, are identical in principle, namely, the exposure of 
 much surface with little loss of space. 
 
 If possible, the observer should inject the blood-vessels of 
 the gills with the conventional crimson and blue wax, showing 
 the currents of the arterial and venous blood. Each lamina 
 forms a most wondrous object, and may be gazed upon for weeks 
 with increasing admiration. 
 
 Every one who has watched the habits of fishes must have 
 noticed that in running waters they always have their heads 
 against the stream, and do not greatly care about shifting their 
 positions. 
 
 In still waters, especially such as those of the ordinary glass
 
 RING AND STAPLE. 415 
 
 aquaria, the fish are perpetually on the move, whereas in such a 
 river as the Dove of Derbyshire, and even the Darenth of Kent, 
 large trout may be seen almost motionless, but invariably with 
 their heads directed up the stream. 
 
 The reason is evident enough. As long as the fish lies with 
 its head up the stream the water flows through its gills, and 
 enables it to breathe. "Were the passage of the water stopped, 
 the fish would be drowned. Consequently, all good anglers, 
 when they hook a fish which is worth taking, keep its head 
 down the stream, prevent the water from washing over its gills, 
 and consequently render it so weak by deprivation of oxygen, 
 that it becomes an easy prey, and is rendered subservient to a 
 line of a single hair. Let the fish breathe, and a single struggle 
 would smash a line of treble the strength. But keep it from 
 breathing by directing its head down the stream, and it rapidly 
 loses all strength, and can be directed into the landing-net, or 
 brought within the scope of the gaff, without a chance of escape. 
 
 I NEED hardly remark that on the right-hand side of the 
 illustration is shown a Laminated Stove, and that on the left 
 are drawings of the gills of the Shark tribe and the common 
 Trout. If the reader would really like to look into the subject 
 for himself, I should suggest the purchase of a cod's head and 
 shoulders and a lobster. The breathing apparatus can be removed 
 from each for examination, and the remainder will serve as a 
 first course for dinner. 
 
 RING AND STAPLE. 
 
 HUMBLE, and apparently insignificant, as the principle of the 
 Ring and Staple may be, we owe no small amount of our 
 domestic comfort to it. It meets us in all kinds of ways, in the 
 hinges of our boxes, in the padlocks of our doors, in the inn- 
 side fastenings for our horses, in the seaside fastenings for ships' 
 cables, and in a thousand other ways too many to enumerate. 
 
 ON the right-hand side of the next illustration is shown the 
 Ring and Staple as used for the purpose of mooring ships and 
 boats, it being absolutely necessary that the machinery, simple
 
 416 
 
 NATURE S TEACHINGS. 
 
 as it is, must be capable of working in any direction, and with 
 some latitude as to the extent. 
 
 On the left hand are shown two of the wonderful bones which 
 are found in the head of the Fishing-frog or Angler-fish 
 
 HKAD-BOXES OF ANGLER-FISH. 
 
 STAPLE AJfD EIXO. 
 
 (Lophius), and which serve as decoys, by means of which the 
 smaller fish are entrapped into the vast jaws of the Angler-fish. 
 
 It is clearly necessary that these singular appendages should 
 be capable of movement in every direction, and this object is 
 attained by the structure which is tere shown, and which is 
 almost equal to the ball-and-socket joint for its freedom of 
 movement. It will even allow of partial rotation, so as to cause 
 the little strip of skin at its end to assume the aspect of a living 
 worm, and entice the smaller fish into the jaws of the dread trap 
 that lies open before them. 
 
 A figure of this fish may be seen on page 92. 
 
 THE FAN. 
 
 EXCEPT in permanently cold countries, a Fan of some kind 
 seems to be an absolute necessity. Sometimes, as in the greater 
 part of Europe, it is used only by the softer sex. The harder 
 sex would often be only too glad to use it if they dared, and the 
 same observation is equally true with regard to the parasol. 
 
 But, in such lands as Japan and China, the Fan is an 
 absolute necessity of existence. Men, women, and children 
 alike carry their Fan, and almost perpetually use it. I
 
 FANS. 
 
 417 
 
 remember, when the troupe of Japanese acrobats were in 
 England, that one of them exhibited the national use of the 
 Fan in an excessively ludicrous manner. 
 
 One of his comrades ascended to the roof of a lofty build- 
 ing, hung by his legs to one of the rafters, and held in his 
 hands a bamboo pole which was twenty feet long. Another 
 Japanese also ascended, climbed over his comrade, and settled 
 on the bamboo pole, to which he clung only by the clasp of his 
 bare feet. Suddenly he slipped down the pole, stopped himself 
 when within a few inches of the end, squatted there with per- 
 fect unconcern, though at least forty feet from the ground, 
 took his fan from the back of his neck, and fanned himself 
 while gravely surveying the startled audience. 
 
 Perhaps some of my readers may remember Chang, the 
 Chinese giant, who, by the way, in private life was a polished 
 gentleman. He was never without his fan, always keeping it 
 
 PALM-LEAF. 
 
 JAPANESE HAND-SCREEN. 
 
 fluttering gently with an ease only to be acquired by a life- 
 long practice, and I really think that if he had been deprived 
 of it he would have been seriously ill. How he slept without 
 it is a wonder, for in his own house the fan was incessantly in 
 motion, and was worked with apparent unconsciousness on his 
 part. 
 
 I have often wished that in our country the ladies would 
 manage their fans in the same quiet way when they are in a 
 church or a concert-room, for the perpetual rattle of the joints 
 is enough to distract any preacher or conductor, and very often 
 does so. 
 
 E
 
 418 NATURE'S TEACHINGS. 
 
 As to the shape of the Fan, it varies greatly according to 
 the country, but it may almost invariably be traced to some 
 familiar object. 
 
 There is, for example, the common Japanese Fan or Screen, 
 which is avowedly made on the model of the Palm-leaf, the ribs 
 of the leaf being represented by split portions of a bamboo 
 stem. The right-hand figure in the preceding illustration is 
 taken from one of the common sixpenny Japanese fans that 
 may be seen in many shop-windows. 
 
 There are exactly sixty ribs in the fan, all produced by 
 splitting the bamboo into strips, kept in their place by a slight 
 rod of the same material, and covered with two pieces of thin 
 printed paper. Seeing that the original cost cannot be more 
 than a penny, it is wonderful how such articles can be pro- 
 duced, and give a living to the makers. 
 
 The reader will observe that the shape of the Japanese Fan 
 is almost exactly that of the Palm-leaf, with the exception of 
 the jagged edges, and a better pattern could not be found. 
 Then there are many Indian Fans framed on the same model, 
 but which revolve on their handles, and are swung slowly 
 round and round by the servants before the guests, and thus 
 become miniature punkahs. 
 
 Here, again, we may find a parallel in Nature. The common 
 hive bee ventilates its dwelling by using its wings in lieu of 
 fans. When the hive is really in want of fresh air, the bees 
 set to work, and wave their wings backwards and forwards for 
 a considerable time, so that they necessarily expel the foul air 
 from the interior of the hive, and create a partial vacuum, 
 which can only be filled by fresh air from without. 
 
 Fans of very similar shape are in use among the South Sea 
 Islanders and the inhabitants of the Essequibo district. They 
 are often used as bellows when a fire has to be raised, but their 
 primary object is to be employed as fans. 
 
 NEXT we come to those fans which are made of flattened 
 sticks, which move on a pivot. This is, indeed, the ordinary 
 form of the fan at the present day, the sticks being sometimes 
 wide enough to constitute the entire fan, but mostly being 
 connected with a sort of lining made with silk, paper, or 
 feathers. Such fans as these can be moved on their pivots, so
 
 BURIAL. 
 
 419 
 
 as to occupy a comparatively small space ; and the same can be 
 said of the modern fender-guards, which can be folded up 
 when the room is unoccupied, and which form an effectual pro- 
 tection against the danger of ladies' dresses coming in contact 
 with the fire. 
 
 Examples of such a screen, and two fans, are given on the 
 right hand of the accompanying illustration. 
 
 On the left hand is shown one of the natural objects from 
 which the fans, &c., might well have derived their origin. It 
 is one of the antennae or horns, as they are popularly called 
 
 ANTEXNA OF COCKCHAFER. IVORY FAN. FEATHER FAN, 
 
 FIRE-GUARD. 
 
 of the common Cockchafer. The end of this antenna is com- 
 posed of a number of flat plates, which work on a pivot exactly 
 like the sticks of a fan, and, like those sticks, can be folded 
 into a wonderfully small compass, or opened out into a fan-like 
 shape. 
 
 BUKIAL. 
 
 LAST scene of all. 
 
 I do not think that it matters very much to one who has 
 " shuffled off this mortal coil " what becomes of the coil in 
 which he had been imprisoned. Whether the abandoned 
 body be buried in the earth, or sunk in the sea, or devoured 
 by wild beasts, or consumed by fire, signifies nothing to him, 
 though it may signify much to his surviving friends. 
 
 As a rule, the animals, of whatever kind they may be, con- 
 trive to dispose of their mortal remains in some mysterious 
 
 E E 2
 
 420 NATURE'S TEACHINGS. 
 
 manner, so tnat not a vestige of them is to be found. Take, for 
 example, the domestic cat, and see how few bodies are found 
 of cats which have died natural deaths. 
 
 For instance, there was my own cat " Pret," who lost his 
 life from the bites of rats. He was blind, and so lamed that 
 he could scarcely crawl. Yet, on the day of his death, he 
 three times escaped from his comfortable bed in front of the 
 fire, dragged himself through a hedge, down a steep bank, 
 across a road, up another bank, through a crevice in a park 
 fence, and curled himself up to die under a blackberry -bush. 
 
 Perhaps it was mistaken kindness on my part, and I should 
 have acted better if I had left him to die in peace. But, 
 though I carried him back three times, and though he was 
 
 BUBYING-ANTS. SAVAGE FUNERAL. 
 
 quite unable to see, he contrived to slip out of the house, and 
 to find the same spot for his last resting-place on this earth. 
 
 I have heard that some cats have been known to bury their 
 young, and Dr. J. Brown tells a most touching story of a dog 
 that committed her dead puppy to the river. 
 
 But as to Insects, until a few years ago, no one ever dreamed 
 that the principle of burial could be found among them. What 
 millions of insects die in every year, and how seldom is a dead 
 insect found ! Flies, gnats, and the smaller insects might 
 escape observation, but the large moths, butterflies, beetles, 
 dragon-flies, &c., are scarcely ever found dead. 
 
 In my own neighbourhood, for example, the Stag-beetle, 
 nearly the largest and most conspicuous of British insects, 
 swarms to an almost unpleasant degree, especially in the 
 summer evenings.
 
 FUNERAL-ANTS. 421 
 
 Yet I have never found a dead Stag-beetle that had not 
 been killed by violence. What becomes of the bodies of the 
 countless millions of creatures that annually pass into their 
 other world is a problem which at present no one seems to be 
 able to solve. 
 
 STILL, there are instances where even insects are known to 
 bury their dead, and I scarcely need say that they are to be 
 found among the Ants. 
 
 The story is a very curious one, and is narrated at length in 
 the Journal of the Linncean Society, vol. v. p. 217. 
 
 It happened that a lady found that her little boy was being 
 stung by ants, and she at once killed them and threw their 
 dead bodies away. After some time a number of ants came 
 out of their nest, formed a procession as regularly organized as 
 that of any undertaker's funeral, dug graves for each dead ant, 
 laid the body in it, and covered it up again with earth. 
 
 They carried their organization to such an extent that they 
 even had relays of bearers. But the strangest part of the story 
 is that several worker ants would not assist in the funereal 
 ceremonies. The soldiers at once set on them, killed them, and 
 tumbled them all promiscuously into a common grave. 
 
 Such scenes were repeatedly witnessed by the lady, a Mrs. 
 Hutton, who wrote the account while she was living in New 
 South Wales.
 
 USEFUL AETS. 
 
 CHAPTER X. 
 
 WATER, AND MEANS OF PROCURING IT. 
 
 The Necessity of Water to Man. Composition of the Human Body. Natural and 
 Artificial Distillation. The Traveller's Tree. Pitcher-plants and Monkey- 
 pots. Stomach of the Camel, and its Analogy to the Honey-comb. Dew- 
 drops. Use of the Still at Sea. Perspiration and its cooling Properties. 
 The Turkish Bath. Perfume and Ether Spray. Condenser of the Low- 
 pressure Steam-engine. The Dry and Wet Bulb Thermometer. Ice pro- 
 duced in a red-hot Vessel. Power of Water. How Fountains are made. 
 Modern System of Hydrants. Hydraulic Mining. The Victoria and 
 Niagara Falls. Artesian Wells. The Norton Tube, &c., in Abyssinia. 
 The Water-ram and Spout-hole. 
 
 TT has often been remarked that man can live a compara- 
 -*- tively long time without solid food, providing that he can 
 only obtain water, of which the chief bulk of the human body is 
 made. Dying by thirst is a horribly painful death, but, 
 according to Mr. Mills, the ill-fated Australian traveller, 
 " starvation on nardoo (an innutritious plant) is by no means 
 unpleasant, but from the weakness one feels, and the utter 
 inability to move one's self." 
 
 Those who have been shipwrecked, and unable to obtain 
 fresh water, have always found that the tortures of thirst were 
 infinitely harder to endure than those of hunger ; and the 
 reader will probably remember that those who perished in the 
 Black Hole of Calcutta owed their deaths chiefly to thirst, 
 their bodies being exhausted of moisture by the heat of the 
 room, and no fresh supply attainable. 
 
 Civilisation especially shows itself in the way in which 
 water is brought within the reach of every one, even in the 
 most crowded of cities. The reader may probably call to 
 mind the wonderful aqueducts of ancient Rome, the gigantic
 
 WATER-TANKS. 
 
 423 
 
 remains of which siill exist. Then, as to our own country, we 
 are all practically acquainted with some water company, by 
 which the water, more or less purified, is brought into our 
 houses, and can be obtained by the mere turning of a tap. 
 
 Yet all this ingenuity is but a following of natural proto- 
 types, as will presently be seen ; and even the familiar Water- 
 tank, as shown at the right hand of the illustration, has been 
 anticipated by Nature. 
 
 ON the left hand of the illustration there are three examples 
 of natural water-tanks, two belonging to the vegetable, and 
 one to the animal kingdom. 
 
 That on the extreme left, with a number of radiations, repre- 
 sents a portion of a Madagascar palm, popularly called the 
 
 TRAVELLER'S TREE. STOMACH OP CAMEL. PITCIIEH-PLANT. 
 
 Traveller's Tree. Having very large leaves, arranged in the 
 manner there shown, the Traveller's Tree condenses the nightly 
 dews, and allows them to trickle down into the hollows of the 
 leaf-stems. 
 
 There the water remains, out of the reach of sunbeams or 
 wind, and if a traveller happens to be thirsty, all he has to do 
 is to pierce the base of one of these gigantic leaves, and out 
 rushes a stream of the purest water, as is shown in the illus- 
 tration.
 
 424 NATURE'S TEACHINGS. 
 
 NEXT to the Traveller's Tree is shown one of those extraor- 
 dinary vegetables called Pitcher-plants, from the strange con- 
 formation of the leaves. They inhabit Borneo, Siam, and other 
 hot countries. In these remarkable plants some of the leaves 
 are developed into suitable pitchers, with hinged lids, exactly 
 like our hot- water jugs. They serve, however, a different office, 
 and contain cold water which the plant has distilled from the 
 dew. 
 
 As the monkeys are in the habit of resorting to these plants 
 when thirsty, they are sometimes called Monkey -pots. There 
 is an admirable account of the Pitcher-plants and their deve- 
 lopment in the Transactions of the Linncean Society, vol. xxii. 
 part iv. The scientific name of those plants is Nepenthes. 
 
 BELOW the vegetable comes a rather celebrated animal cis- 
 tern, namely, a portion of one of the stomachs of a Camel. 
 
 It exactly corresponds with that part of an ox which butchers 
 call "honey-comb tripe," and consists of a multitude of cells, 
 which can be closed or opened at will. When the camel takes 
 in its provision of water, it can treat this portion of the stomach 
 much as the hive bee treats the honey-bag, and fill its cells 
 with water. 
 
 By degrees, when it finds the necessity for moisture, it can 
 squeeze the water out of these receptacles into the digestive 
 portion of the interior, and so can sustain life for a wonderfully 
 long time under conditions which would kill any other animal. 
 I may remark, by the way, that the amount which a camel can 
 drink, and the length of time through which it can endure its 
 desert life, have been much exaggerated. There is another 
 point to be considered, namely, the curious resemblance between 
 these cells and the honey-comb of the hive bee. Every one 
 knows that honey, no matter how tightly closed, will crystallize 
 and lose its best qualities if kept in jars, whereas if it be 
 allowed to remain in the waxen comb, where it is divided into 
 very small portions, it will remain good for years. 
 
 It is just the same with the cells of the camel's stomach, 
 they being able to preserve water in a pure state by distributing 
 it among a number of small cells, which can be opened or closed 
 at will. 
 
 Then we come to the various means of obtaining water.
 
 DISTILLING. 
 
 425 
 
 Keference has already been made to the Filter, by which foul 
 water can be made pure for human consumption, and we will 
 therefore pass to another mode of obtaining pure water, namely, 
 the Still. 
 
 In former days, if there were a failure of the supply of fresh 
 water on board ship, the whole of the occupants must necessarily 
 perish. Now, however, no such danger exists, as every well- 
 furnished ship carries at least one Still, by means of which the 
 sea-water can be made to abandon its salt, and to give out 
 nothing but pure water fit for drinking. 
 
 Even in cases where no regular Still has been on board, an 
 extemporised Still has been made from a kettle, a gun barrel, 
 or piece of lead piping, or anything of a similar nature. 
 
 The principle of the Still is simple enough, and is shown by 
 the diagram, rather than drawing, on the right hand of the 
 illustration. There is a vessel in which liquid is boiled. 
 From the upper part of it rises a tube through which the 
 
 steam must pass as it is generated. The tube in question is 
 generally of considerable length, and is coiled inside a vessel 
 filled with cold water, rendered colder by ice, if possible. 
 
 As the steam passes through the cold tube condensation 
 takes place, and it becomes liquid again, but deprived of its 
 heavier particles, so that if sea- water be placed in the still, the " 
 salt is left in the vessel, and nothing but pure water passes 
 through the tube. In dissecting-rooms a small still is almost 
 invariably kept. Many preparations are of such a nature that 
 the spirit in which they are placed becomes discoloured, and 
 has to be repeatedly changed. Now, even methylated spirit is
 
 426 NATURE 8 TEACHINGS. 
 
 an expensive article, and therefore, instead of being thrown 
 away, the discoloured spirit is placed in the still, and repro- 
 duced in a clean and transparent state. 
 
 Nature affords innumerable examples of distillation, the chief 
 of which are the Dewdrops which have already been mentioned. 
 During the daytime the air is full of moisture drawn by the 
 sunbeams from ocean. We cannot see it, but it is there, and 
 when the chill of night cools the various trees, herbage, and 
 other such objects, the aerial moisture is condensed upon them, 
 which is then known by the name of Dew. 
 
 On the left hand of the illustration are shown the tiny Dew- 
 drops as hanging on the slight threads of a spider's web, and 
 collected in larger drops upon a leaf. 
 
 THERE are many other familiar examples of the principle of 
 condensation, the commonest of which is the so-called steam as 
 it pours from the spout of a kettle. In point of fact, it is not 
 steam at all, but only water condensed into very small drops. 
 At the orifice of the kettle it is quite invisible, but when it 
 passes into the air, and is condensed, the tiny globules become 
 visible. The same fact may be noticed in the Napier's Coffee 
 Machine, which has already been mentioned. When the water 
 is boiling in the glass globe no steam is visible, though the 
 upper portion of the globe is entirely filled by it. But, no 
 sooner is the cork removed, and the steam allowed to escape, 
 than it at once becomes visible as a white cloud, being, indeed, 
 a miniature copy of the rain- clouds that float above us. 
 
 THEN there is that mostly invisible passage of liquid through 
 the multitudinous pores of the body, which is generally known 
 as perspiration. It is invisible in warm weather, but on a cold 
 day is as visible as a rain cloud. 
 
 The Turkish Bath affords a good example of this fact. Some- 
 times the hottest room attains a temperature of 250 or more, 
 water boiling at 212. When a bather goes into that room, 
 he appears to have a perfectly dry skin, the moisture being in 
 the form of invisible steam, and swept off as soon as it is gene- 
 rated. 
 
 But, if he passes at once into the cold room, he is so enveloped 
 in vapour that for a few moments he is wrapped in it as in a
 
 EVAPORATION. 
 
 427 
 
 cloud, and can scarcely be seen, the vapour having been con- 
 densed by the cold air. 
 
 A very familiar instance of this sudden condensation may be 
 seen in the streets of London on any winter day. There may 
 be a couple of omnibus horses, nearly at the end of their day's 
 work, and quite tired out. Suddenly they are pulled up by the 
 
 HEATED HORSE. 
 
 PERFUME SPBAr. 
 
 PHEEZIJJG BY EVAPORATION. 
 
 WET-BULB 
 THERMOMETER. 
 
 driver, and as suddenly disappear for a moment or two, being 
 concealed in a cloud of moisture proceeding from their bodies. 
 Of course in a hot day there is more of the moisture, but the 
 warmth of the atmosphere prevents it from condensation, and 
 so it is not visible. 
 
 One valuable property of the system of evaporation and 
 condensation is its cooling power. Thus it is that a person who 
 is ill with fever tosses about with a burning skin until the 
 pores of the body act, and allow the normal moisture to pass 
 through them. Then the body cools by evaporation, and the 
 patient begins to amend. 
 
 So it is that the bather can endure in the Turkish bath a 
 heat so great that a glass of water, if held in the hand, would 
 speedily boil, and a piece of meat be cooked in about the same 
 period. But, if the air were not dry enough to carry off the 
 perspiration, the bather would be scalded to death. 
 
 A most valuable adaptation of the principle is shown in the.
 
 428 NATURE'S TEACHINGS. 
 
 little glass machine for dispersing perfumes in the form of 
 spray. In cases of headache it is almost invaluable, the spray 
 cooling the heated forehead like magic, and at the same time 
 filling the room with the grateful perfume. 
 
 It has even a greater claim to human gratitude, as I 
 can personally testify. I have the strongest objection to a 
 surgeon's knife, especially when I know, from sad experience, 
 that he is going to make very free use of it. But, on the last 
 occasion, I cared nothing for it, owing to the happy invention 
 called Ether Spray. 
 
 The effects were remarkable. First, a delicious cooling of a 
 spot raging with internal fires. Then it was rather colder than 
 I liked. Then it was much colder than I liked. Then it 
 became almost too cold to bear, reminding me of my child- 
 hood's feet on the outside of the Birmingham coach in the 
 depth of winter. 
 
 Suddenly all sensation ceased, and the skin became white as 
 parchment. Out came the surgeon's bistoury, and I looked at 
 him with as calm composure as if he had been whittling a deal 
 plank. There was absolutely no feeling whatever, the local 
 nerves having been temporarily frozen, so great is the power of 
 evaporation. If it ever be my lot again to endure cold steel, I 
 shall have the ether spray. 
 
 ON the extreme right of the illustration is seen the " Wet- 
 bulb " Thermometer, which carries out the same principle, the 
 thermometer being double, and one bulb being covered with a 
 wet envelope, while the other is dry. 
 
 Below is one of the many inventions for making artificial ice, 
 all of them depending on the cooling power of evaporation. 
 Perhaps some of my readers may have seen molten iron poured 
 over the human hand without doing the least harm, or 
 mercury frozen in a red, or rather a white, hot vessel. Both 
 these phenomena are due to the cooling power of evaporatioc, 
 which is made to act with extreme rapidity, and so absorbs the 
 heat until even mercury is rendered solid, and can be cast in a 
 mould like a leaden bullet. 
 
 IN the accompanying illustration we have an example of the 
 Condensating principle as applied to the steam-engine, and
 
 THE CONDENSER. 
 
 429 
 
 popularly known as the " Low-pressure Engine." In this 
 case force is reconverted, so to speak, and, if a cubic inch of 
 water has been converted by heat into a cubic foot of steam, 
 creating a pressure in one direction, it can be reconverted by 
 cold, and so produce a pressure in another direction. 
 
 IT is owing to this fact that some parts of the world are 
 always hot and always wet, Guiana being a striking example. 
 
 The wind blows over the ocean, absorbing moisture as a 
 sponge does water. As it passes from the sea over the land, it 
 is met by secondary mountain ranges, too low to arrest its pro- 
 
 IIA1X-CLOUD. 
 
 COXDEKSEK. 
 
 gress altogether, and high enough to have their summits clothed 
 in eternal snows. As soon, therefore, as the warm, water-laden 
 winds pass over these mountains, the moisture is condensed by 
 their frozen tips, and down rushes the rain in torrents. 
 
 Even in our own temperate land we can often trace the 
 cause of a heavy rain to the presence of a lofty hill, or even an 
 exceptionally tall spire. The moist climate of Oxford has been 
 attributed by scientific men quite as much to its spires and 
 towers as to its low-lying situation. 
 
 Now we come to the various modes of extracting the water 
 which is laid up within the earth, and which only slowly 
 ascends to the surface when drawn up by the heat of the sun. 
 
 Water is everywhere, but the depths at which it is found are 
 vastly different. For example, at one house in which I lived 
 it was not possible to dig for three feet without coming to 
 water. In another, no water was found within some two 
 hundred feet, and, as I several times relieved the old gardener 
 of the task of drawing the water for the day's consumption, I 
 have reason to remember the depth.
 
 430 
 
 NATURE S TEACHINGS. 
 
 The pail, rope, and winch which were in use at that time 
 and may be still, to the sorrow of the gardener are but a 
 sort of semi-savage way of procuring water from the depths of 
 the earth. It is a well-known fact that under certain condi- 
 tions water always finds its own level, minus the friction of the 
 
 channel through which it passes. On this principle all foun- 
 tains are made. Those, for example, at the Crystal Palace, 
 which fling their waters to such a height, are fed from tanks 
 on the summit of the two great water towers. And, were it 
 not for the friction of the water in the tubes, and that of the 
 air, the fountains would rise as high as the tanks from which 
 they are fed. 
 
 Such is the case with springs, especially with those of an 
 intermittent character, in which latter instance the rushing of 
 the water is exactly coincident with the filling of the hidden 
 tank which supplies it. 
 
 The modern Hydrant system, which bids fair to supersede 
 the cumbrous machinery of fire-engines, even when worked by 
 steam, is based on the same principle. The water-tanks are 
 placed at such a height that, when a hose is attached, and the 
 tap turned, the water can be thrown over the roof of the 
 highest building. Such hydrants have been attached to Can- 
 terbury Cathedral since the fire which so nearly consumed that 
 magnificent and venerable building. 
 
 A VERY remarkable use has been made of this power of 
 water in mining operations. Most of my readers know that in 
 gold mines the metal is chiefly found scattered among quartz, 
 one of the hardest of the minerals. The usual plan has been 
 to dig out the quartz, pound it to powder with specially
 
 HYDRAULIC MINING. 431 
 
 devised machines called " stamps," to pass the powder through 
 mercury, which amalgamated with the gold, and gave it up 
 again on being heated to a certain temperature. 
 
 Now a different mode of mining is brought into operation, 
 the pickaxe, spade, and stamps, with all their expensive machi- 
 nery, being abandoned, and water made to do the duty of all 
 three, some ingenious individual having noticed the effect which 
 water has on the hardest rock. 
 
 Such, for example, is the case with those wonderful Vic- 
 toria Falls of Africa, where the rushing water has cut its 
 sinuous channel through so many hundreds of yards of rock. 
 Such, also, is the case with the more celebrated, but not so 
 wonderful, Falls of Niagara, which have been gradually work- 
 ing their way backwards, having worn away the rocks over 
 which they fall, and which are shown to be many miles away 
 from the spot where the river first discharged itself over the 
 cliff. 
 
 In fact, it is well known that the Falls are receding at a 
 definite rate annually, and that the rate has been calculated 
 
 HYDRAULIC MIXING. WATHB-FALL. 
 
 with scientific accuracy. The cliffs of our own coasts say of 
 Margate or Ramsgate crumble away with equally calculable 
 speed. 
 
 In the hydraulic mining system large tanks are erected, at 
 least two hundred feet above the level of the mine. From 
 these tanks proceed pipes, terminated by hose, just like those 
 of our ordinary fire-engines. The miners, instead of using 
 pickaxe or crowbar, simply direct the streams of water against 
 the solid rock. Their effect is tremendous. They tear it 
 to powder, and carry it down the wooden troughs called
 
 432 NATURE'S TEACHINGS. 
 
 " flumes," in which the mercury is so arranged that not a 
 single atom of quartz rock can pass without having its gold 
 extracted. 
 
 The following graphic account of Hydraulic Mining at 
 Nevada is taken from Mr. J. K. Lord's " Naturalist in British 
 Columbia : " 
 
 "Near Nevada are the famed Hydraulic washings. The 
 gold is disseminated through terraces of shingle conglomerates, 
 often three hundred feet in thickness. These terraces are 
 actually washed entirely off the face of the country hy pro- 
 pelling jets of water against them, forced by pressure through 
 a nozzle. 
 
 " To accomplish this, the water is brought in canals, tunnels, 
 and wooden aqueducts, often forty miles away from the ' draft/ 
 This supply of water the miners rent. 
 
 " As we near the washing spot, in every direction immense 
 hose, made of galvanized iron, and canvas tubes six feet round, 
 coil in all directions over the ground like gigantic serpents, 
 converging towards a gap, where they disappear. 
 
 " On reaching this gap, I look down into a basin or dry 
 lake, three hundred feet below me. The hose hangs down this 
 cliff of shingle, and following its course by a zigzag path, I 
 reach a plateau of rock, from which the shingle has already 
 been washed. 
 
 " A man stands at the end of each hose, that has for its head 
 a brass nozzle. "With the force of cannon-shot, water issues in 
 a large jet from this tube, and propelled against the shingle, 
 guided by the men, washes it away as easily as we could sweep 
 a molehill from off the grass. 
 
 " The stream of water, bearing with it the materials washed 
 from out the cliff, runs through wooden troughs called 'flumes/ 
 floored with granite. These ' flumes ' extend six miles. Men 
 are stationed at regular distances to fork out the heavy 
 stones. 
 
 "Throughout its entire length, transverse strips of wood 
 dam back a tiny pond of mercury. These are called ruffles 
 gold-traps, in other words, that seize on the fine dust-gold 
 distributed through the shingle. The flumes are cleaned about 
 once a month, and the gold extracted from the mercury. 
 
 " I try with a powerful lens to detect gold amidst the mate-
 
 ARTESIAN WELLS. 
 
 rial they are washing, but not a trace is discoverable, and yet 
 it pays an immense profit to the gold- washers." 
 
 THERE are two more modes of extracting water, which will 
 be but cursorily mentioned. 
 
 The reader will remember that water finds its own level, and 
 that the terrific power of hydraulic mining is owing to the fact 
 that the water expends its force against the solid rock instead 
 of ascending into the air. 
 
 It is now found that, even without artificial assistance, water 
 has a habit of finding its own level, and that, if it be allowed 
 its own course, it will contrive to find its way nearly to the 
 highest point whence it derived its origin. On this principle 
 
 ARTESIAN WELL. TfORTON S TUBE. 
 
 are based the Artesian Wells, which, when they " strike 
 water," spurt it up in a torrent, as is the case with the now 
 celebrated Norton Tubes, which are screwed down into the earth 
 like hollow gimlets, and which always contrive to extract the 
 water hidden beneath the surface of the earth. 
 
 The success of our army in Abyssinia was greatly owing to 
 these Norton Tubes, which, being of small diameter and of 
 peculiar make, could be screwed into the ground when the 
 troops made a halt, unscrewed when they left the spot, and 
 used again for the next halt. 
 
 Similarly, the French used the Artesian-well system with 
 wonderful success in Northern Africa. Water is the chief 
 necessity of life in that part of the world, and a nation who 
 could cause pure cold water to spring out of the hot and thirsty 
 sands was naturally looked upon as something more than 
 human. 
 
 Yet the principle was exactly the same in both cases. Water 
 
 F F
 
 434 
 
 NATURE S TEACHINGS. 
 
 is always latent somewhere beneath the surface of the earth, 
 and, if a tube can be driven deep enough, the water will come 
 up it. 
 
 The accompanying illustration shows the Artesian Well and 
 Norton's Tube, and their similitude in principle, the tube pene- 
 trating through various layers of soil, until it reaches the 
 water which it seeks. 
 
 THEN there is another way by which water can be made to 
 force itself to a considerable height. Not being much of a 
 mathematician, I do not recollect the exact proportional 
 height to which a stream of water may raise itself, but if any 
 one can secure a fall of some eight or ten feet, he can furnish 
 his house with water by means of the "Ram," a chart of 
 which is shown in the illustration. 
 
 The principle of the Ram is, that the water is allowed to 
 flow down a tube, when it meets with a valve. This valve is 
 
 SPOUT-HOLE. 
 
 WATER-RAM. 
 
 suddenly closed by the pressure, and the water is forced 
 onwards by the shock. Much water escapes at each blow of 
 the valve, but that does not signify. 
 
 The force of water thus suddenly stopped is hardly appre- 
 ciated. Even in ordinary houses the sudden turning of a 
 water-tap has been known to burst the pipe and deluge the 
 house with water. 
 
 IN Nature a similar effect is produced, called popularly the 
 " Spout-hole."
 
 THE WATER-RAM. 435 
 
 It is a hole or tunnel on the seashore, passing upwards from 
 the level of the sea to the summit of the cliff. 
 
 When the waves are urged against the tunnel by the wind, 
 the water is dashed into it. Being partially checked by the 
 friction, which acts exactly like the water that is checked by 
 the Ram, the wave hurls itself up the channel, and flies out in 
 showers of spray, high above the level of the original wave 
 which caused it. 
 
 In the illustration are shown the Water-ram with its 
 globular valve, and the safety or escape valve of the waste 
 water. On the left is shown one of the natural Spout-holes, 
 with the water dashing through its tunnel into a mass of 
 spray.
 
 USEFUL ARTS. 
 
 CHAPTER XL 
 
 AEROSTATICS. WEIGHT OF AIR. EXPANSION BY HEAT. 
 
 Ascent and Descent. The Balloon and the Parachute. Description of the 
 Balloon. The Montgolfier Balloon Causes of its Abandonment. The Gas 
 Balloon. Hydrogen Gas and its Manufacture. The Gossamer Spider. 
 Reasons of its Ascent and Descent. Many Species of Gossamers. Desi/rip- 
 tion of the Parachute. Its Mode of Action. A Balloon converted into a 
 Parachute. Toy Parachutes. Natural Parachutes. The Dandelion Seed 
 and its Structure. The Flying Squirrel. The Flying Monkey. Flying 
 Mice and Flying Opossums. The Flying Dragon and its Pseudo-wings. 
 The Flying Frog. Weight of Air. Pressure per Square Inch. The Air 
 Ocean and its Storms. Principle of Air-currents. The Sun, the Earth, and 
 the Air. Ventilation of Mines. Choke-damp and Fire-damp. The Air- 
 shafts. Chimneys of Factories. The Steam-blast. The Barometer, and 
 Mode of its Construction. Water and Mercury. Sucking Eggs and Sugar- 
 cane. Expansion of Water and Metals by Heat. The Thermometer. 
 Wheel-making. 
 
 AEROSTATICS. 
 
 WE will begin this chapter with the only two modes at 
 present known by which man can ascend from the earth 
 or descend to it with safety, namely, the Balloon and the 
 Parachute, the latter being generally attached to the former, 
 and detachable at pleasure. 
 
 The Balloon is, in fact, as its name imports, a large, hollow, 
 air-tight ball, filled with some substance lighter than ordinary 
 air. The original Balloons by Montgolfier were filled with 
 heated air exactly like our toy fire-balloons. Just as the 
 supply of hot air is kept up in them by a sponge dipped in 
 lighted spirits of wine, so in Montgolfier 's balloons the same 
 object was attained by straw which was kept continually 
 burning in a grate. 
 
 There were, however, two disadvantages about this plan. The 
 first was the great danger of fire, which on one occasion did
 
 BALLOONS. 
 
 437 
 
 ignite a balloon when at a great height. The second was the 
 perpetual labour required in keeping the fire alight. Straw 
 burns very rapidly, and so the aeronaut had no opportunity of 
 making those meteorologic observations in which consist almost 
 the entire value of the balloon. 
 
 Then it was thought that hydrogen gas, being about four- 
 teen times lighter than ordinary air, would answer the purpose, 
 and such has proved to be the case. Formerly the gas was 
 
 GOSSAMER EPIDEE. 
 
 made at great expense from sulphuric acid and zinc, but it 
 is now found that the common coal-gas is quite as efficient, 
 very much cheaper, and fills the balloon much more rapidly. 
 
 THE same principle, though not the same form, is found in 
 Nature. 
 
 There are certain tiny spiders called Gossamers, which have a 
 curious power of floating in the air. They have been seen on 
 the tops of lofty spires, and they are sometimes so numerous 
 that the air is full of their floating webs, and the ground is 
 white with those that have descended. 
 
 Their mode of ascent is this. They climb to the top of some 
 elevated object, if it be only a grass-blade. They then pour 
 out a tuft of long, slender threads, which shortly begin to 
 tend upwards. As soon as the Spider feels the pull, it crawls 
 upon the web, and sails away into the air. The duration and
 
 438 NATURE'S TEACHINGS. 
 
 height of the ascent depend much on the wind and character of 
 the atmosphere. 
 
 The weh ascends because it is for the time lighter than the 
 atmosphere. But, as it gradually becomes laden with the 
 moisture that more or less fills the air, it becomes heavier than 
 the atmosphere, and gently sinks to the ground. 
 
 What may be the object of these aerial voyages no one knows. 
 They may be for the purpose of capturing minute insects, or 
 they may be for mere amusement. But in either case they are 
 highly instructive, as showing the principle on which the balloon 
 was framed. 
 
 The little Gossamer Spider is shown on the left hand of the 
 illustration, clinging to its floating web. I believe that the 
 Gossamer is not a single species of Spider, but that there are 
 many species which deserve the name, being able to float in the air 
 when they are small, but losing that capacity as they increase 
 in size and weight. 
 
 Now we come to another branch of the same subject, namely, 
 the safe descent from a great height by means of the Parachute. 
 
 On the right hand of the illustration is the ordinary Para- 
 chute as it appears when open and closed, in either case having 
 somewhat the appearance of a large umbrella. It is hung to 
 the balloon in its closed state, and when detached it falls 
 rapidly for a yard or two with startling rapidity. The pressure 
 of the air thus forces the ribs open, and gives sufficient assist- 
 ance to the atmosphere to insure a gentle fall. 
 
 On one memorable occasion, when the late Albert Smith was 
 in the car of a balloon upwards of a mile from the ground, the 
 balloon burst. Fortunately it burst so completely, that the 
 silk was driven into the closely meshed netting, and formed an 
 extemporised parachute, which took the voyagers to the earth 
 with safety, except some rather severe bruises. 
 
 Children often amuse themselves with miniature parachutes. 
 They take a square piece of thin paper, tie threads to the four 
 corners, and then bring the ends together, a cork taking the 
 place of the car. They then launch it from a high window, 
 and should there be a favourable breeze, it is wonderful how far 
 it will be carried before it comes to the ground. 
 
 Once, when a boy of eleven, and consequently thoughtless,
 
 PARACHUTES. 
 
 439 
 
 I set a chimney on fire by one of these Parachutes. I wished 
 to see whether it would go up the chimney, and come out at the 
 top. Unfortunately it was caught by a flame as it was 
 launched, flew up in full blaze, and, as the chimney needed 
 sweeping, the result was inevitable. 
 
 IN the centre of the illustrations, and at the top, are two 
 examples of a well-known natural Parachute called the 
 
 FLYING SQUIRREL. 
 FLYING DRAGON. 
 FLYING FBOG. 
 
 DANDELION SEED 
 (OPEN AND CLOSED). 
 
 PARACHUTE 
 
 (OPEN AND CLOSED). 
 
 Dandelion seed. The resemblance to the real Parachute is 
 wonderful, the actual seed occupying the place of the car, and 
 fulfilling the same office, i.e. keeping the seed upright until it 
 reaches the ground. 
 
 When the tuft is closed, as is the case before the pretty ball 
 of seeds bursts from the green envelope in which they had been
 
 440 NATURE'S TEACHINGS. 
 
 confined during the process of development, its form bears the 
 same startling resemblance to the Parachute. 
 
 PASSING from the vegetable world, there will be seen three 
 examples of Natural Parachutes. Several others will be men- 
 tioned, but we have no space for description or figure. It will 
 be seen, however, that the one principle which characterizes 
 them all is the exposure to the air of a flattened and large sur- 
 face, in proportion to the size of the object. 
 
 Before beginning the description, however, I must mention 
 that nearly all animal parachutes can to a certain extent guide 
 their course, while neither the balloon, the gossamer, the para- 
 chute, nor the various winged seeds have the least power of 
 guidance, but must follow every current of air in which they 
 may happen to float. 
 
 THE upper figure represents a Flying Squirrel. 
 
 There are many species of Flying Squirrel, but they all agree 
 in one point. The skin of their sides is modified into a very 
 thin fold, which extends as far as the feet. 
 
 It is very elastic, so that when it is not in use it falls into 
 folds or wrinkles, and is hardly perceptible. But should the 
 Squirrel wish to pass from one tree to another, without coming 
 to the ground, it spreads its legs as widely as possible, so as to 
 stretch the membrane into a wide, flat surface. It then boldly 
 springs into the air, and sweeps upon its mark with a sort of 
 skimming movement. Except that it does not revolve, it 
 passes through the air much after the fashion of an oyster- 
 ihell when thrown horizontally. 
 
 Many mammalia are constructed after a similar fashion, such 
 as the Colugo, or Flying Monkey, the Flying Mice, and the 
 Flying Phalangists, or " Opossums," as they are popularly 
 called. 
 
 IN the centre is the Flying Dragon, or small lizard, which 
 very probably gave rise to the fabled Dragons in which our 
 ancestors so devoutly believed. Indeed, on looking back at 
 the old illustrated works on Natural History, there can be but 
 little doubt on the subject. 
 
 In this creature, the ribs, instead of the legs, carry the
 
 THE FLYING FROG. 441 
 
 flat and elastic membranes. When simply crawling on the 
 branches, after the manner of tree-lizards, the ribs lie flat 
 against the sides, and the membranes collapse, so that the 
 shape of the body is little different from that of any crawling 
 lizard. 
 
 But the ribs are movable at will, and, when the creature 
 wishes to pass from one tree to another, it extends the ribs, 
 stretches the membranes, and launches itself into the air, 
 exactly as has been narrated of the Flying Squirrel. 
 
 THE lowest figure represents a most extraordinary animal, 
 called the Flying Frog. Only one specimen is believed to be 
 known, and that was discovered in Borneo by Mr. Wallace. 
 
 Here we have an analogy with the bats of the present day 
 and the pterodactyles of the past, namely, the elongation of 
 the toes, and the stretching of a web between them. In the two 
 latter animals, however, only the toes of the two fore-legs are 
 elongated, whereas, with the Flying Frog, the elongation is 
 found in both pairs of limbs. The ends of the toes are fur- 
 nished with adhesive pads, like those of the tree-frogs, to 
 which it is probably related. 
 
 By means of the four membranes, the creature is able to 
 sweep through the air for some distance, and, indeed, this power 
 was the reason why it was caught. It was seen to skim from 
 one tree to another, and was immediately secured. Had it 
 remained sticking on the tree, it would probably have escaped 
 observation. 
 
 WEIGHT OF AIR. 
 
 WE have already noticed that hydrogen gas is fourteen 
 times lighter than air, and infer necessarily that the weight of 
 the atmosphere must be very considerable if so heavy an object 
 as a balloon, with its car, instruments, sand-bags, and pas- 
 sengers, can rise and float in it. 
 
 We are not conscious of its weight, because it permeates us, 
 and the pressure is neutralised. But, in fact, we live at the 
 bottom of a vast ocean which we call the atmosphere ; and as, 
 on an average, there is a pressure of fifteen pounds on every 
 square inch of surface, we have to sustain an almost incredible
 
 442 
 
 NATURE S TEACHINGS. 
 
 weight. Let, for example, any one measure the surface of his 
 own hand, reduce it to square inches, add together fifteen 
 pounds for every square inch, and he will then appreciate the 
 weight of the atmospheric ocean in which we live. On an 
 average, every human being endures a pressure of some ninety 
 thousand pounds. 
 
 This ocean is in perpetual movement, sometimes violently, 
 which we call storm ; sometimes gently, which we call breeze ; 
 and sometimes very gently, which we call calm. There are 
 air-spouts as well as water-spouts ; and, in fact, the water-spout 
 is nothing but a continuance of the air-spout, as is shown by 
 the moving sand-columns of the desert. Whatever may be 
 the character of the winds, as we call this movement, the air is 
 never for a moment still ; and, indeed, were it to be still for any 
 time, the whole human race would perish. 
 
 How winds are caused we shall see by the aid of the 
 diagram on the left-hand side of the illustration. 
 
 AIB-CUBBBNTS. 
 
 VENTILATION OP MINES. 
 
 The original cause is the sun. His rays fall upon the earth, 
 heating it, and so by radiation heating the air. Now, as has 
 been remarked, heated air will cause a heavy balloon to float 
 through ordinary air, and to carry up a considerable amount of 
 dead weight besides ; consequently the heated air must ascend, 
 while cool and heavier air rushes in to take its place, and thus 
 the currents are produced. Were the earth set straight 
 upright, the currents would invariably run in one direction ; 
 but, as it is tilted on one side, the needful variety is obtained, 
 and we find the winds blowing from all parts of the compass. 
 
 The principle, therefore, of all winds is, that heat expands,
 
 VENTILATION. 443 
 
 and therefore becomes lighter than air at an ordinary tempera- 
 ture. 
 
 WERE it not that man has taken advantage of this principle, 
 there could not be a deep mine in England. In any deep 
 excavation, even though it be a well, foul air, mostly composed 
 of carbonic acid gas, always collects, and, being much heavier 
 than atmospheric air, lies at the bottom of the pi't as surely as 
 hydrogen would rise out of it. To breathe this air is as certain 
 and as sudden death as to take prussic acid, and no mine can 
 be worked as long as " choke-damp " is in it. 
 
 In coal mines there is an additional source of danger, namely, 
 the coal gas, which is nearly identical with our coal gas of the 
 streets, and takes fire when brought into contact with flame. 
 To rid the mines of these gases, a simple, ingenious, and 
 effectual remedy is used. A ventilating shaft is made, which 
 reaches from the bottom to the mouth of the pit. At the 
 bottom, diagonal shafts are made, entering the main shaft, as 
 shown on the right hand of the illustration. One of these is 
 connected with a furnace, and the other, or others, open into 
 the mine. 
 
 The heat of the furnace rarefies the air in the shaft, 
 causing it to rush upwards with great violence, and so, by 
 creating a partial vacuum, to force the air in the shaft to follow 
 it. The loss of air thus caused is supplied by fresh air from 
 above, which, by the law already described, is obliged to take 
 the place of that which was driven out. Thus a complete 
 circulation of air is kept up, and a well-managed mine has a 
 fresher atmosphere than many houses in which the windows are 
 mostly kept shut, and the only ventilation is accomplished by 
 occasionally open doors. 
 
 The "draught" of our domestic chimneys is owing to this 
 principle, and the reason why factory chimneys are built of such 
 enormous height is, that the column of heated air may be 
 increased, and consequently that the draught may be stronger, 
 and the heat of the furnace made fiercer. 
 
 The " Steam-blast," by which the escape steam of engines 
 is sent into the chimney, is another example of this principle, 
 the steam taking the place of the hot air. 
 
 Further examples of the weight of the atmosphere are given
 
 444 
 
 NATURE S TEACHINGS. 
 
 in the illustration. That on the right represents the common 
 Wheel Barometer, which marks the weight of the air by a 
 hand moving in front of a dial. If the hand move towards the 
 right, the weight of the air is increasing ; if to the left, it is 
 decreasing. 
 
 There are certain words, such as Wet, Change, Fair, Dry, 
 &c., on the face of the dial, but they are only conventional, the 
 real test of the weather being the direction in which the hand 
 moves. .For example, if with a west wind the hand moves 
 from Dry towards Fair, rain may be expected ; whereas, if it 
 should move from Wet to Change with an east wind, we may 
 reasonably think that fine weather is coming. 
 
 The whole cause of this revolution of the hand may be found 
 in the weight of the atmosphere. 
 
 It is found that a column of water thirty feet high, or a 
 column of mercury thirty inches high, is exactly equal in 
 weight to a column of air of the same diameter, but some forty 
 odd miles high, so that the two columns precisely balance each 
 other. 
 
 Suppose, then, the water or mercury to be placed in tubes 
 closed at the top and open at the bottom, the water or mercury 
 will exactly balance the air, and will not escape from the tubes. 
 
 SUCKING SUGAR-CANE. SUCKING AN EGG. 
 
 BAROMETERS. 
 
 ll, it 
 
 It necessarily follows that if the air be heavier than usual 
 will force the liquid higher into the tubes, and, if it be lighter 
 than usual, will allow them to fall lower. This is the principle 
 of the Barometer.
 
 PRINCIPLE OF THE BAROMETER. 
 
 445 
 
 The mechanism of the hand and dial is shown in the diagram 
 which occupies the centre of the illustration. For convenience, 
 sake the mercury column is mostly employed, but several 
 Water Barometers, some thirty feet in length, have been con- 
 structed. 
 
 ON the left hand is seen a boy engaged in sucking an egg. 
 The plan employed is simple enough. A tolerably large hole 
 is made at one end, and a very small one at the other. The 
 yolk having been broken up by a long needle, or similar imple- 
 ment, the larger hole is placed to the lips, and, suction being 
 used, the contents pass into the mouth. 
 
 AVere it not for the hole at the end opposite the mouth, it 
 would be impossible to extract the contents, but the air rushes 
 through the aperture, and so forces out the contents of the egg. 
 
 Above is a representation of the way in which Sugar-cane is 
 sucked. The reader probably knows that the Sugar-cane, like 
 the wheat-stem, has knots at certain intervals, which divide 
 the cane into a number of separate parts. 
 
 There is quite an art in sucking the Sugar-cane. If a joint 
 be cut off, and the lips applied to the end, not a drop of the 
 sweet juice would be extracted. But if a notch be cut close to 
 the joint, as shown in the illustration, the air can gain access, 
 and then the juice flows easily enough. 
 
 IT has already been mentioned that air expands when heated. 
 The same rule holds good when applied to other objects, such 
 
 BOILING WATKB. 
 
 THERMOMETER. 
 
 as the various liquids, metals, &c. A very familiar example of 
 this fact is the " boiling over " of water, when the vessel has
 
 446 NATURE'S TEACHINGS. 
 
 been filled too much to allow for the expansion of the heated 
 liquid. 
 
 Advantage has been taken of this principle in the formation 
 of the Thermometer, a word which signifies " heat-measurer." 
 Liquid of some kind is placed in an hermetically sealed tube, 
 generally terminating with a bulb, and in proportion to the 
 heat the liquid expands, and is forced up the tube. 
 
 Any liquid will answer to a certain extent, but, as water 
 freezes at 32, it would be useless for measuring degrees of cold 
 below the freezing point. Coloured spirits of wine are used ; 
 but the very best liquid is mercury, which is a metal in a state 
 of fusion. 
 
 This expansion by heat is so powerful in iron, that it is 
 utilised in several ways. 
 
 Take, for example, wheel-making. The iron tire is made 
 rather smaller than the wheel, and is then placed in a fire until 
 it is red-hot. It then expands so much that it can be easily 
 slipped over the wheel as it lies on the ground. Cold water is 
 then dashed on it, and the tire contracts with tremendous force, 
 binding the parts of the wheel firmly together. 
 
 In all buildings where iron is much used, such as iron 
 bridges, iron beams, &c., it is necessary to make allowance at 
 both ends, so as to permit the iron to expand on a hot day and 
 contract on a cool one. Buildings formed of stone and iron 
 were once thought to be safe in case of fire. They are now 
 known to be just the contrary, the stone flying with the heat, 
 and the iroii expanding,
 
 USEFUL AETS. 
 
 CHAPTER XII. 
 
 The Cassava Press and its Structure. Mode of using it. The Siamese Link. 
 An ingenious Robbery. Muscles and their Mode of Action. Human Arms 
 and Steelyard. Change of Direction. The Human Hand and Wrist. 
 Story of a Carpenter. The Pulley. Reduction by Friction. Past and 
 present Engines. Oiling Machines. Treatment of the Sewing Machine. 
 Use of Paraffine. Disuse of Machine hurtful. Human Joints. Synovia 
 and its Value. Disuse of Joints hurtful. The Lazy-tongs and its Useful- 
 ness to Invalids. Suggestions for Improvement. Larva of the Dragon- 
 fly and its Mask. Curious Mode of seizing Prey. Proboscis of the House- 
 fly, and Mode of using it. The Apple-parer. Squirrel and >Tut. Structure 
 of Teeth. Rock - splitting. Powers of Ice. How the Pebble-ridge is 
 formed. Splitting Stones by Moisture. The Diamond Drill. Ovipositor of 
 the Gad-fly. Curious Similitude of Structure. 
 
 MEANS AND APPLIANCES. 
 
 Fthis chapter we will take some miscellaneous appliances of 
 force both in Art and Nature. 
 
 In the accompanying illustration is shown the Cassava Press 
 of Southern America, a most effective and simple instrument 
 for extracting the juices of the root. These juices are poisonous 
 when raw, hut, when properly boiled and cooked, they make an 
 excellent sauce. 
 
 The press in question is an elastic tube made of flat strips of 
 cane woven together exactly like the "Siamese Link," which 
 will be presently described. The cassava root, after having 
 been scraped until it resembles horseradish, is forced into the 
 press until it can hold no more. The result is, that the tube is 
 shortened and thickened, being widest in the middle. 
 
 It is then hung by its upper loop to the horizontal beam of a 
 hut. A long pole is passed through the lower loop, the short 
 end is placed under a projecting pag on the upright post of the 
 house, and a heavy weight attached to the longer end. A 
 powerful leverage is thus obtained, the tube is forcibly short-
 
 448 
 
 NATURE S TEACHINGS. 
 
 ened, and the juice exudes through the apertures of the woven 
 cane. 
 
 When it begins to run slowly, a woman seats herself at the 
 end of the pole, so as to increase its weight. I must mention 
 here that in the illustration the press is too near the middle 
 of the pole. This is because the exigences of our page do not 
 
 CASSAVA PKKS8. 
 
 admit of the requisite length. But if the reader will kindly 
 assume the end to which the stone is attached to be three or 
 four times longer, he will have an idea of the great power 
 which is exerted upon the cassava. 
 
 On the left hand of the illustration is the same cassava press 
 as seen when empty, and both figures, as well as that of the 
 pot for receiving the juice, are taken from specimens in my col- 
 lection. 
 
 Ox the right hand of the following illustration is the Siamese 
 Link, which caused such a sensation when it first came out. 
 
 A finger is inserted at each end, and, when the owner attempts 
 to withdraw them, the Link contracts, and the harder the pull, 
 the tighter is the hold. If the fourth instead of the first finger 
 be employed, the hold of the Link is exceedingly strong. 
 
 The only mode of release is by pushing the fingers together, 
 when the Link will relax. It should then be held bv the
 
 THE SIAMESE LINK. 
 
 449 
 
 remaining fingers of one hand, so that it shall not contract 
 again, and the finger of the other hand comes out at once. 
 
 An ingenious robbery was once committed by means of the 
 Siamese Link. A man of good address struck up an acquaintance 
 with a jeweller. One day he produced a Siamese Link, and 
 challenged him to get his fingers out when once they were 
 So the jeweller was told to put his hands behind his back, 
 
 m. 
 
 and push his little fingers as far in as he could. 
 
 This he did, when the treacherous friend made a clean 
 sweep of all the rings, brooches, ear-rings, and such jewellery 
 as was within his reach, while the unfortunate jeweller was 
 
 MUSCLES OP LEG. 
 
 SIAMESE LINK. 
 
 vainly tugging at the Link. This only occupied a few seconds 
 for a practised hand, and the thief quietly opened the door, 
 shut it, and was lost in the passing crowd before the jeweller 
 could recover from his surprise. 
 
 ON the left of the same illustration is a view of the muscles 
 of the human leg, which, as the reader will see, are curiously 
 like the distended cassava press. Although the mode of apply- 
 ing the force differs, the principle is the same. 
 
 In the latter case an external force is applied to the press, 
 but in the latter an internal, or rather a central, force is 
 
 G G
 
 450 NATURE'S TEACHINGS. 
 
 applied to the bones. It is evident that if a similar process 
 were carried on with the cassava press, and the central 
 portion forcibly distended, the supports at either end would be 
 drawn powerfully towards each other. Substitute the muscle 
 for the press, and the bones for the poles, and this is muscular 
 action. 
 
 HERE we have a diagram which speaks for itself, as far as 
 muscular action is concerned, but there is another point to 
 which we shall presently pass. 
 
 The muscle of the arm is seen running along the bone, 
 passing over the elbow, where it is held down by a tendinous 
 band, and, by its contraction, enabling the arm to be bent so as 
 to uphold a considerable weight. The mechanical analogy 
 
 HUMAN ABM. STEELYARD. 
 
 between this arrangement and the common Steelyard is too 
 evident to need any explanation except inspection of the 
 diagram. 
 
 THERE is, however, another point which is worthy of con- 
 sideration. The muscle does not proceed at once from the 
 shoulder to the wrist, but passes under the tendinous band 
 above mentioned, and so produces a change of direction when 
 the arm is bent. 
 
 There is a more complicated arrangement of a similar 
 character in the human hand, a diagram of which is given in 
 the left-hand figure of the accompanying illustration. 
 
 The fingers are, of course, moved by a set of tendons, and 
 the muscles, from which these tendons spring, are attached to 
 the fore-arm (I purposely omit the scientific titles, though 
 they would be much easier to write). Any of my readers can 
 prove this for themselves.
 
 MUSCULAR ACTION. 451 
 
 Let him first grasp the upper arm firmly, and bend the 
 limbs, and he will at once find that the swelling of the muscle 
 shows the source of power. 
 
 Then let him do the same, but grasp the fore-arm, and he 
 will find that the muscles are quiescent, showing that the 
 former set of muscles belong to the entire arm, and not to the 
 fingers, while the muscles of the lower arm have nothing to do 
 with the bending of that limb. 
 
 Now let him grasp the fore-arm, and open and close the 
 fingers, and he will feel a whole set of muscles rise, and swell 
 and harden under his grasp. Next let him bend his hand 
 inwards, and he will find that the fingers work perfectly well, 
 though the direction of force is changed. 
 
 This is owing to a band of tendons passing across the 
 wrist, under which the finger-tendons play. The course of 
 the tendons is marked in the illustration by leaving them 
 white. 
 
 The wondrous structure of the human hand and its multitu- 
 dinous tendons can only be appreciated by actual dissection, 
 but an idea of their variety and use may be obtained by watch- 
 ing the hands of a skilful pianoforte-player. This struck me 
 forcibly the first time that I ever heard Thalberg play. 
 
 While on the subject of tendons, I may mention a curious case 
 A journeyman carpenter missed a blow with his axe, and 
 struck his left hand at the junction of the thumb and wrist. 
 The important tendon was severed, and the inner muscles, 
 having no counteracting force, dragged the thumb into the 
 hollow of the hand. 
 
 To all appearance, the man could no longer earn a living as 
 a carpenter. But he would not be discouraged, and while he 
 was in hospital he borrowed a book, and studied the 
 anatomy of the human hand. By means of this knowledge he 
 constructed a sort of semi-glove, in which he introduced pieces 
 of watch-spring, that supplied the place of the lost tendon. 
 
 Not content with this, he studied Euclid for the purposes of 
 his trade, so as to get the most possible out of a piece of wood 
 of given dimensions, and be able to go straight to his mark by 
 a problem, instead of doing it slowly and clumsily with a two- 
 foot rule and a pair of compasses. When I saw him last he 
 was a master carpenter in a large and increasing business. 
 
 a o 2
 
 452 
 
 NATURE S TEACHINGS. 
 
 MAN lias unconsciously imitated Nature in the invention of 
 the Pulley, whereby the direction of force may be altered 
 almost at will. In this case the cord takes the part of the 
 working tendon, and the Pulley of the fixed tendinous cross- 
 bar. There is much matter of interest in the tendons, but, 
 as our space is fast waning, I must resist the temptation of 
 describing them. 
 
 IN all machinery one of the chief objects of the machinist 
 is to reduce friction as much as possible. He makes all the 
 joints as smooth as tools can polish, and always introduces oil 
 or some lubricating substance into the joints. Otherwise the 
 
 TENDONS OP HAND. 
 
 engine rattles with a noise proportionate to its power, and 
 wastes its force on the friction. 
 
 In my childish days a steam-engine of any kind used to 
 rattle so loudly that conversation was almost impossible. Now 
 they are made with such perfection, that the vast engines in use 
 at the pumping stations of the metropolitan drainage are almost 
 absolutely silent. 
 
 There is the enormous hall, filled with gigantic beams and 
 rods, and cranks, and wheels. A single man turns a little 
 handle, and the whole machinery starts into life. Beams rock, 
 cranks and wheels revolve, rods slide up and down, and all in a 
 silence which is nearly appalling in its manifestation of 
 unassuming strength. Indeed, many a hand sewing machine
 
 LUBRICATION. 
 
 453 
 
 makes far more noise than one of those giant engines, and all 
 because in the latter friction is avoided as far as possible, every 
 screw is well braced up, and every joint is kept well lubricated. 
 Here I may observe that few sewing machines get fair play. 
 They rattle, they squeak, they become stifier daily, they snap 
 the thread, and then decline work altogether. And in almost 
 every case this is done by neglect on the part of the owner, 
 who does not lubricate every point of the machine which works 
 upon another. 
 
 Ladies especially are very careless in this respect, and will 
 mostly omit three or four of the oiling points. They might just 
 as well omit them all, as a single unoiled point will disarrange the 
 harmonious motion of the whol% machine. I have often been 
 called in as surgeon in such cases, and have almost invariably 
 
 LTJBBICATION OF JOINT. 
 
 OILING MACHINE. 
 
 been able to point to several spots which needed oil, and did not 
 get it. Sometimes, out of false economy, an inferior oil is used, 
 which speedily clogs and hardens, and stops all movement. IB 
 such a case the best remedy is to apply paraffine liberally, 
 and use it for a quarter of an hour or so. It will soon dissolve 
 the clogged oil, which may be worked out by turning the 
 handle or crank of the machine. 
 
 Of course the best remedy is to take the machine to pieces, 
 polish the joints, lubricate them, and put it together again. 
 But this is a perilous process, and an amateur, if he tries it, will 
 generally find himself with half-a-dozen pieces for which he 
 can find no place. Paraffine will answer every purpose, and I 
 have released many a stiffened machine by its use.
 
 454 NATURE'S TEACHINGS. 
 
 Then some people leave their machines untouched for days, or 
 even weeks, and then wonder that they work stiffly. Every 
 day the machine should be worked, if only for a few seconds, 
 and then it will seldom stiffen. It is just the same with steamers. 
 When they are in harbour, though the fires be out, and they 
 are not meant to move for weeks, the engines are always turned 
 round at least once daily. 
 
 BOTH these rules hold good in the animal kingdom. 
 
 To every joint there are attached certain glands that supply 
 a kind of oily substance technically named "synovia," which 
 acts exactly the same part as the oil or grease of machinery. 
 If these glands do not do their iuty, and the supply of synovia 
 be defective, the joints become stiff, painful, and crackle when 
 they are moved. 
 
 Then, exactly as the joints of a machine become stiff from 
 non-usage, so do those of a human being. We will take, for 
 example, the Indian Fakirs who vow that they will not move 
 some limb from a definite posture. At first the exertion is 
 trying and painful, but by degrees the disused joints lose their 
 faculty of motion, and, even if their owner wished to move a 
 limb, he could not do it. 
 
 The right-hand figure of the illustration represents the 
 lubrication of an ordinary sewing machine, and the left-hand 
 figure is a section of the human knee-joint, showing the gland 
 which supplies the synovia. 
 
 PERHAPS some of my readers may think that such a subject as 
 the "Lazy -tongs" is too trivial for a work which deals, however 
 lightly, with science. But there may be some who know the 
 inestimable benefit of Lazy-tongs under certain conditions. 
 
 There are many cases where a severe injury has occurred, or 
 where rheumatism has fixed its tiger-claws in the joints, so 
 that movement is all but impossible. There may be no one in 
 the room to help the invalid, and even to stretch the arm over 
 the table is as impossible as to jump over the house. 
 
 Then it is that the real value of the Lazy-tongs becomes 
 manifested, and that it shows itself in the light of a supple- 
 mentary limb. With a mere movement of the fingers it can 
 be stretched across any table which is likely to be placed before
 
 LAZY-TONGS. 455 
 
 an invalid, and seize the required object by the tongs at the 
 further end. 
 
 The only drawback to its use is, that the instrument cannot 
 be shortened without opening the tongs. But, if some plan 
 could be devised whereby the tongs could retain their hold 
 under those conditions, the instrument would be a perfect one. 
 
 EXACTLY such a Lazy-tongs we have in Nature, in the well- 
 known "mask of the larva and pupa of the Dragon-fly." It 
 is called a mask because, when closed, it covers the face. 
 
 It chiefly consists of two flat, horny plates, hinged in each 
 other like a carpenter's two-foot rule, and being capable of 
 extension to a considerable length. The end is widened, and 
 
 LAZY-TONGS. 
 
 furnished with two jaws, which take the part of the tongs in the 
 instrument above described. 
 
 This curious apparatus is used for the purpose of securing 
 prey. 
 
 I have kept many of these creatures, and watched their mode 
 of feeding. As has already been mentioned, they have two 
 modes of progression, i.e. walking by means of legs like those 
 of ordinary insects ; and driving themselves along by ejecting 
 water from the tail, on the principle of the rocket. As far as 
 I have seen, the latter mode is always used in taking prey. 
 The Dragon-fly larva always lives at the bottom of the water, 
 though it can force itself to the surface if needful. And, like 
 the dreaded ground-shark, it seizes its prey from beneath. 
 
 Its favourite food is the larva of the whirlwig-beetle, a 
 fat white grub, with a number of white, soft, feathery gills 
 fringing its sides. In order to produce a current of air over 
 these gills, the larva wriggles itself up to a height of severaJ
 
 456 
 
 NATURE S TEACHINGS. 
 
 inches, and then sinks slowly down, with the white gills 
 floating on either side. 
 
 Should a Dragon-fly larva be near, it sees the grub ascending, 
 glides quietly under it without using its legs so as to cause 
 alarm, waits for it to sink, darts out the mask, seizes it in the 
 jaws, drags it to its mouth, and the grub is seen no more. So 
 voracious are these larvae, that, if only two are kept in the same 
 vessel, one is sure to devour the other. 
 
 ANOTHER good example of the Lazy-tongs is the Proboscis of 
 the common House-fly. We have all seen these insects alight 
 near sugar, or any other tempting food, unfold the proboscis, 
 pour a drop of liquid in the sugar, dissolve it, suck it up, and 
 then shut up the proboscis as if by hinges. 
 
 ANOTHER labour-saving machine is the Apple-parer, a com- 
 paratively modern invention. The principle is, that a knife is 
 
 8QUIBBBL AND NUT. 
 
 APPLE PABEB. 
 
 pressed lightly by a spring against a revolving apple, and set 
 at such an angle that nothing but the outside peel can be 
 removed. Where large numbers of apples have to be pared, as 
 in making preserves or in hotels, this is a most useful inven- 
 tion. 
 
 When I first saw it at work, the operation seemed familiar 
 to me, but I could not at first remember the parallel. At last 
 it flashed across me that a Squirrel eating a nut was the natural 
 parallel of the Paring Machine. 
 
 After splitting the shell and extracting the kernel, the
 
 POWER OF ICE. 
 
 457 
 
 Squirrel takec the latter between its fore-paws, presses it 
 against its upper incisor teeth, and makes it revolve rapidly. 
 In a second or two the kernel is perfectly peeled, and is then 
 eaten. 
 
 In this case the incisor teeth of the Squirrel take the part of 
 the knife, the muscles of the leg that of the spring, and the 
 sharp edges of the upper teeth that of the knife. The struc- 
 ture of the Rodent teeth has already been explained in 
 page 233. 
 
 THE wonderful effects of water in breaking up the hardest 
 rock have already been described. We will now proceed to 
 another branch of the same subject. 
 
 Perhaps some of my readers may have wandered along our 
 
 FROST-CLEFT BOCK. 
 
 STOXE-SPLITTIXG. 
 
 rocky coasts, and have seen how large masses of rock are con- 
 tinually detaching themselves, though they are so hard that a 
 cold chisel is needed to make any impression upon them. 
 
 Then they fall into the sea, and are rolled backwards and 
 forwards until they become smoothed and rounded, and are 
 called pebbles, while the portion that is rubbed off them is 
 called sand. The phenomenon is well shown in the wonderful 
 Pebble Ridge of North Devon. 
 
 The real agent is ice. 
 
 We all know that, when water freezes, it expands consider- 
 ably. This accounts for two phenomena. 
 
 First, as it expands, it becomes lighter than water, and con- 
 sequently floats on the surface. 
 
 Next, there are few of us who have not seen water-bottles
 
 458 NATURE'S TEACHINGS. 
 
 cracked by the freezing of the water. The most common, and 
 perhaps the most unpleasant, example of this propensity is the 
 bursting of water-pipes in the winter, followed by a flooding of 
 the house when the thaw comes. 
 
 This is caused by the expansion of the frozen water, which 
 will burst not only a thin leaden tube, but a stout iron vessel. 
 Care should therefore be taken, at the beginning of winter, to 
 cover up all exposed portions of leaden pipes, and there will 
 then be no danger. There was one pipe in my house that was 
 always bursting, but after I covered it with two or three layers 
 of carpet placed loosely over each other, so as to entangle the 
 air and form a non-conductor, the pipe has never frozen, and 
 the water supply has been uninterrupted by the severest 
 frosts. 
 
 I am told that a still better plan exists, especially in places 
 where the pipes cannot be thoroughly protected by external 
 wrappings. Let six inches or so of the leaden pipe be removed, 
 and its place supplied by a vulcanised india-rubber tube. 
 
 The ice must expand somewhere, and chooses the spot where 
 least resistance is offered to it. Consequently, it expands in 
 the india-rubber tube, but does not break it, and, when the 
 thaw comes, there is no overflow of water. 
 
 MAN utilises this power of ice in stone-splitting. Instead of 
 taking the trouble to cut the stone by manual labour, the work- 
 men bore a series of holes, fill them with water, insert tightly 
 a wooden plug to prevent the ice, when formed, from oozing 
 out of the holes, and leave the rest for the frost to do. 
 
 A like effect is produced in the warm weather by sub- 
 stituting similar plugs, but quite dry, having been baked for 
 hours in an oven, for the purpose of driving out every particle 
 of moisture. These plugs are hammered into the holes as 
 deeply as they will go, and there left. Even if there be no 
 rain, the nightly dews make their way into the pores of the 
 dry wood, and cause it to swell with such irresistible force 
 that the stone is split with scarcely any manual labour on the 
 part of the workmen. 
 
 YET another plan for cutting hard stones. Some of my 
 readers may be aware that a singularly ingenious instrument
 
 THE DIAMOND DRILL. 459 
 
 has been invented for cutting holes in granite and other 
 hard rocks. It is called the Diamond Drill, because its tip is 
 armed with uncut diamonds. 
 
 It is necessary that the diamond should not be cut, as the 
 natural edges are needed. A glazier's diamond, for example, 
 is always set as it came out of the mine. The stories that are 
 told about cutting out panes of glass with a diamond ring are 
 all absurd. A diamond, when it has once passed through the 
 hands of the jeweller, cannot cut glass. It can scratch glass, 
 but not one whit better than a flake of ordinary flint. 
 
 It is found that the Diamond Drill works with wondrous 
 rapidity, cutting away the stone with ease, and suffering 
 
 BOBEK OF CESTUUS. DIAMOND-BEADED BOKEE. 
 
 scarcely any damage itself. The tube to the end of which the 
 diamonds are fixed is generally made in telescopic fashion, so 
 as to allow it to penetrate deeply into the rock, without the 
 necessity of shifting the machine by which it is turned. I 
 need hardly say that its rate of speed is very great indeed. 
 
 OUR old friend, the Gad-fly, again affords an example of a 
 parallel. 
 
 The ovipositor is tubular, telescopic, and furnished at the 
 top with five little hard, sharp, scaly knobs, which act the 
 same part as the diamonds of the mining tool. Even the scoop- 
 like shape of the tip, and the telescopic shaft, are almost iden- 
 tical in both instances.
 
 USEFUL ARTS. 
 
 CHAPTER XIII. 
 
 TELESCOPIC TUBES. DIRECT ACTION. DISTRIBUTION OP 
 WEIGHT. TREE-CLIMBING. THE WHEEL. 
 
 Telescopic Tubes, their Structure and Uses. The Japanese Fishing-rod. The 
 Tripod Wheel-bearer and its Telescopic Structure. The Rat-tailed Maggot. 
 Locomotion. Direct Action. The Rocket, the Water Tourniquet, and 
 Electric Tourniquet. Cuttle-fish. The Flying Squids. The Paper Nau- 
 tilus. Proceedings of newly-hatched Calamaries. Larva of the Dragon- 
 fly. Distribution of Weight. The Snow-shoe, its Structure and Mode of 
 using it. The Skidor of Norway. A formidable Rifle Corps. The Mud- 
 patten. Foot of Duck tribe. Foot of Jacana. Locomotion of Water- 
 gnat. Tree-climbing. Mode of ascending Palm-trees. The Value of a 
 Hoop. The "Girt Pupa" and Butterfly. Principle of the Wheel. The 
 primitive Wooden Wheel. Spoked Wheels. Driving Wheel of the Bicycle. 
 Naturally spoked Wheel of the Chirodota. 
 
 MEANS AND APPLIANCES (continued). 
 
 WE will now treat rather more in detail the two subjects 
 which were lightly touched upon at the end of the last 
 chapter. 
 
 The reader will remember that the diamond-headed borer 
 is made in telescope form, so as to be adjustable at pleasure. 
 It was also remarked that the ovipositor of the Gad-fly was 
 made in a similar fashion, so as to be withdrawn within the 
 body of the insect when not needed, and protrusible to a con- 
 siderable extent when the Gad-fly wishes to deposit her eggs. 
 
 As to our modern telescopes and opera-glasses, they are so 
 familiar that there is little use in describing them, except to 
 say that their framework consists of a number of tubes of gra- 
 dually lessening diameter, the one sliding within the other, so 
 that the instrument can be lengthened or shortened at will, so 
 as to suit the focus of the observing eye. 
 
 A very ingenious adaptation of the telescopic principle is 
 seen in the Japanese fishing-rod, which is now tolerably well
 
 TELESCOPIC TUBES. 461 
 
 known. Our own telescopic rods require to be withdrawn at 
 the butt-end, and then fitted together in front. But the 
 Japanese rods are so made that, after taking off the ferrule of 
 the seeming walking- stick, a mere fling of the hand will send 
 joint after joint flying out, and fixing themselves in regular 
 succession. So admirably are these rods made, that even 
 blowing into the butt-end will have the same effect. 
 
 ONE of the most perfect, if not the most perfect, example of 
 the telescopic tube is to be found in the Tripod Wheel-bearer 
 (Actinurus), one of the numerous aquatic Rotifers. 
 
 It is not usually so small as the generality of its class, being 
 nearly one-twentieth of an inch in length, and visible to the 
 
 ACTINUBU8 TAIL, OPEN AND CLOSED TELESCOPE. 
 
 (MAGNIFIED). 
 
 unassisted eye, provided that the owner of the eye in question 
 knows how to use it. 
 
 When placed under a microscope of moderate power, the 
 Actinurus is seen to be built almost wholly upon the telescopic 
 pattern. Only the centre of the body remains stationary, the 
 two ends being framed on the principle of the telescopic tube, 
 and capable of being enclosed within the central portion, just 
 as is the case with the Japanese fishing-rod. 
 
 In the illustration the Actinurus is shown in two attitudes. 
 In the upper figure it is represented as having the fore-part 
 of the body entirely, and the tail part nearly, withdrawn within 
 the central portion. The lower figure shows the same speci- 
 men with all its telescopic tubes drawn out to full length.
 
 462 
 
 NATURE S TEACHINGS. 
 
 The creature is perpetually elongating and contracting its 
 body by means of these tubes, so that a measurement of its 
 length is not easy to obtain. 
 
 A full and interesting description of this curious Rotifer may 
 be found in Gosse's "Evenings at the Microscope," p. 300. 
 The long tails of the Rat- tailed Maggot, already described 
 under the head of Diving, are good examples of the draw- 
 tube as found in Nature. 
 
 LOCOMOTION. DIRECT ACTION. 
 
 THE second point which has to be elucidated is that or 
 progress by means of Direct Action. 
 
 NAUTILUS. ROCKKT. 
 
 LARVA OF DRAGON-PLY. WATER TOURNIQUET. ELECTRIC TOURNIQUET. 
 
 We have already seen how vessels can be propelled by sail, 
 oar, paddle, or screw. We have now to consider a mode of 
 progress which requires none of these things, but which works 
 by means of Direct Action. 
 
 Such, for example, is the progress of a Rocket through the air. 
 
 The heated gases rush out with tremendous violence, and, 
 by their pressure, urge the heavy rocket into the air with the 
 rush, roar, and bang so familiar to all who have witnessed a 
 good display of fireworks.
 
 DIRECT ACTION. 463 
 
 A rocket in the act of ascent is shown in the uppermost figure 
 of the accompanying illustration. 
 
 Below it is shown the Water Turhine, the principle of which 
 is evident from the sketch. 
 
 From each of the apertures a stream of water is forcibly 
 directed, and, by its resistance, spins the vessel round and 
 round. There are several shops in London in which this 
 instrument may be seen at work. 
 
 Although in such positions it is necessarily a mere toy, it 
 carries with it, in common with many other toys, the germs of 
 valuable inventions. Indeed, there have been attempts to 
 utilise the principle of Direct Action in the propulsion of 
 vessels, but as yet the mechanical difficulties have proved 
 practically insuperable, and, although a vessel has been thus 
 propelled, the expense has been heavier than that of the paddle 
 or screw, and the speed not nearly so great. 
 
 On the right hand of the illustration is another example of 
 Direct Action, called the Electric Tourniquet. 
 
 In the two previously mentioned instruments the motive 
 power is visible, but in this it is invisible except in the dark. 
 
 The principle is exactly the same as in the pocket or water 
 tourniquet ; but, instead of heated air or a stream of water, 
 electricity is used. The instrument is attached to an electric 
 machine, and fully charged. The electric fluid rushes out of 
 the points, forces itself against the air, and so, by its recoil, 
 drives the machine round and round upon its pivot. 
 
 WE will now take two examples of Direct Action as found 
 in Nature. 
 
 Perhaps many of my readers have seen the Octopus, and 
 admired the manner in which it glides through the water, 
 trailing its long arms behind it. Whence the force comes is 
 not easily seen, and the creature appears to move almost by 
 volition. In reality, however, it employs Direct Action. It 
 takes water into the body, and then it ejects it through a 
 tube called the " siphon " with such force that the animal is 
 propelled backwards through the water. 
 
 Some of the creatures belonging to the Cuttles, and popu- 
 larly called Squids, can use such extraordinary powers that 
 they can project themselves far out of the water. In con-
 
 464 NATURE'S TEACHINGS. 
 
 sequence of this power, they are sometimes called Flying 
 Squids, and, as they have been known to shoot themselves 
 completely over the hull of a large ship, they well deserve the 
 name. 
 
 The common Squid ot our coasts, which furnishes the 
 so-called Cuttle-bone, affords us a good example of Direct 
 Action. I once hatched a number of young Squids from the 
 grape-like eggs, and it was most curious to see how the little 
 creatures shot about as soon as they escaped from the egg. 
 
 They also utilised the siphon in another way, Poising 
 themselves just above the sand with which the bottom of the 
 vessel was covered, they directed a stream of water upon it, 
 and thus formed little cavities into which they settled like 
 birds into their nests. 
 
 The figure represents the Paper Nautilus as it appears while 
 passing through the water. Just at the base of the tentacles 
 is seen the short siphon, from which it is pouring the stream of 
 water which drives it along. 
 
 Below the Nautilus is seen the larva of the common Dragon- 
 fly. "We have, when treating of the Lazy-tongs, already 
 described the mode in which the insect takes its prey, and our 
 object could not be served by repetition. Suffice it to say 
 that the insect is shown in the act of ejecting water, and so 
 shooting itself along in preparation for seizing prey. 
 
 DISTRIBUTION OF WEIGHT. 
 
 BEING on the subject of locomotion, we will examine a few 
 of the contrivances by which a man is enabled to pass in 
 safety over soft substances into which he would otherwise 
 sink. 
 
 The first and best-known of these is the Snow-shoe of 
 Northern America. It is a framework of wood, shaped as 
 shown in the upper figure on the right-hand side, and strength- 
 ened by two cross-bars. The interior of the " shoe " is filled in 
 with hide thongs arranged much like those of a racket, and 
 stretched as tightly. The front of the snow-shoe is slightly 
 turned up, so as to avoid the danger of the point sticking in 
 the snow, an event which, however, generally happens to a 
 novice.
 
 THE SNOW-SHOE. 
 
 465 
 
 These instruments are of considerable size, a specimen in 
 my collection measuring exactly five feet in length, by fifteen 
 inches in width. 
 
 Supported on the snow-shoe, the hunter is enabled to glide 
 unhurt over the deep snow in which he must have sunk without 
 some such aid. He can thus hunt the bison, the wapiti, or 
 any of the larger animals, being able to pass rapidly over the 
 surface, while they are laboriously ploughing their way through 
 the snow-drifts. 
 
 FEET OF DUCKS. 
 FOOT OF JACANA. 
 WATER-GNAT. 
 
 SNOW-SHOE. 
 MUD-PATTEN. 
 SKIDOB. 
 
 It occasionally happens that the snow falls before the shoes 
 are ready. In this case the hunter is obliged to extemporise 
 snow-shoes by cutting them out of thin boards. 
 
 Several years ago, when snow fell heavily and remained 
 unmelted for many days, some Canadians, who were visiting 
 England, made quite a sensation by donning their snow-shoes, 
 and travelling over the snow-clad country. It was very pretty 
 to see the easy way in which they could shoot down a hill, 
 and to watch the peculiar gait which is needed by the snow- 
 shoe. 
 
 H H
 
 466 NATURE'S TEACHINGS. 
 
 AT the bottom of the illustration is shown a portion of a 
 curious skate used in Norway, and called Skidor. 
 
 These remarkable implements achieve by means of length 
 the task which the snow-shoe accomplishes by width. They 
 are made of wood, and, though but a few inches in width, are 
 ten feet or more in length. One is always a few feet shorter 
 than the other, for the convenience of turning. Much practice 
 is needed for the management of the Skidors, but, when they 
 are fairly mastered, they enable their owner to travel at a 
 wonderful pace. 
 
 The Norwegian hunter is quite as dependent on his Skidor 
 as the North American on his Snow-shoe, and uses it for 
 exactly the same purpose. A corps of these hunters has been 
 organized for war, and very formidable they were, hanging on 
 the skirts of the enemy, and giving him no rest, day or night. 
 They never came within fifty yards of each other, so that even 
 cannon were useless ; and, as soon as they thought that they 
 were endangered, they dispersed in all directions, only to reunite 
 and swoop down again on the enemy at the first opportunity. 
 
 THE central figure represents the Mud-patten, which, as its 
 name implies, plays the same part towards mud that the snow- 
 shoe and skidor do to the snow. Like them, also, it is not easy 
 to manage ; and a novice is tolerably certain to drive the front 
 of the patten into the mud, and so get an awkward and not 
 aromatic fall. 
 
 This patten, which is merely a square piece of board attached 
 to the foot, is in use on many of our coasts where the ebbing 
 tide runs out to a great distance, leaving a vast expanse of soft 
 mud. Like the skidor and the snow-shoe, it is mostly used by 
 sportsmen, especially in the winter, when wild-duck shooting 
 sets in. 
 
 Aided by the pattens, a sportsman can travel for miles over 
 mud that would otherwise swallow him up, shoot his birds, 
 and secure them when fallen. While engaged in winter 
 shooting on the Medway, we have often lost birds because 
 they fell beyond a deep mud-bank, and we had no means of 
 crossing it. 
 
 ON the left hand of the illustration are some natural paral-
 
 TREE-CLIMBING. 467 
 
 lels of these artificial aids. The two upper figures represent 
 two forms of webbed feet, and the analogy between them 
 and the snow-shoe and mud-patten is too obvious to need 
 explanation. 
 
 In the centre is the foot of the Jacana, an Asiatic bird. Its 
 foot may well be taken as the analogue of the skidor, length 
 taking the place of breadth, and enabling the weight to be 
 distributed over a large surface. 
 
 This bird finds its food in rivers and lakes, and, by reason of 
 its enormously long toes, can walk with safety over slight 
 floating vegetation, which would give way at once under the 
 tread of any bird except a Jacana. Very good representations 
 of this bird are to be seen in Japanese works of art, especially 
 those which are mounted as screens. Even the peculiar gait of 
 the bird is given with marvellous truth. 
 
 The last figure represents the common Water-gnat (Gems), 
 which may be seen in almost any piece of fresh water, however 
 small. Ponds that are open to the south, and sheltered from 
 the north wind, are its favourite localities. 
 
 It is a carnivorous being, feeding almost wholly on insects that 
 fall into the water. In order to capture them, it runs rapidly 
 over the surface of the water, thf long slender legs distributing 
 its weight over a large surface, and so keeping it from sinking. 
 Only the last two pairs of legs are employed for this purpose, 
 the first pair being held in front of the body, and used for the 
 purpose of capturing prey. 
 
 TREE-CLIMBING. 
 
 ANOTHER curious aid to locomotion is shown in the accom- 
 panying illustration. 
 
 In many parts of the world, where the cocoa-nut palm grows, 
 the natives have invented a simple, but ingenious, plan for 
 ascending the tall, curved stem. Such a thing as an upright 
 palm-tree is unknown, .and consequently the ascent of the 
 branchless stem is not an easy task without artificial assistance. 
 
 When I treated of Warfare and the different modes of scaling 
 walls, the climbing- spur was casually mentioned. The imple- 
 ment of the palm-climber, however, is simpler and more 
 eflfective, as it leaves both hands at liberty when desired. 
 
 HH 2
 
 468 
 
 NATURES TEACHINGS. 
 
 The man cuts a long piece of one of the tough and almost 
 unbreakable creepers which festoon the trees of tropical climes. 
 He passes it round the trunk which he wishes to climb, and 
 fastens the ends firmly together, so as to form a large loose hoop. 
 He then passes the hoop over his head, until it presses against 
 his back, as seen in the illustration, and serves to support him 
 as he leans against it. 
 
 Taking the hoop by the two sides, he lifts it up the trunk as 
 far as he can, places the soles of his feet against the tree, and 
 so walks up it, hitching the hoop upwards at every step. When 
 
 GIRT PUPA AND BUTTERFLY. 
 
 CUMBrv'G PALM-TREE. 
 
 he has reached the top of the tree, he supports himself entirely 
 by the hoop, while his hands are at liberty to be used in getting 
 the cocoa-nuts. 
 
 IN the insect world there are many examples of support 
 being given by a belt passing round the body. 
 
 Among the Butterflies, for example, there are many which, 
 in their pupal stage of existence, are attached to upright stems. 
 They are fixed to the stem by a few threads at the tail, answer- 
 ing to the feet of the tree-climber, while the body is kept in 
 position by a stout silken thread passed loosely round it. 
 
 The illustration represents the pupa of the common Swallow- 
 tailed Butterfly, while in the centre is the same insect in the 
 perfect state as it appears when resting. It really seems as if
 
 THE WHEEL. 469 
 
 the ancient habit of the pupa had been remembered by the 
 perfect insect, the long ends of the hinder wings taking the 
 place of the pupal tail, and the legs that of the belt. 
 
 THE WHEEL. 
 
 YET another aid to locomotion is found in the WHEEL, a 
 contrivance for diminishing friction. 
 
 When man first learnt that heavier weights could be dragged 
 than carried, he simply placed them on flat boards to which 
 ropes were attached. The next step was necessarily the 
 invention of the sledge, the burden resting on two parallel 
 runners, the ends of which were slightly curved so as to prevent 
 them from hitching against any small obstruction. In some 
 countries such, for example, as in Esquimaux-land the sledge 
 is the only vehicle practicable, and even Europeans, when 
 
 WHEEL-SPICULE OP CHIEODOTA. CABT-WHEEI* 
 
 they visit that country, are fain to adopt the sledge if they 
 would live. 
 
 But, in more temperate zones, the Wheel is paramount. In 
 its earlier stages the wheel was a very simple business. It 
 was simply a section of a tree-trunk, dubbed roughly round, 
 and with a hole in the centre, through which the axle passed. 
 Such wheels are still in existence in many parts of Europe ; 
 and, owing to the want of regularity of outline in the circum- 
 ference, and the utter absence of grease, the wheels keep up 
 a continuous shriek, almost deafening to those who are unused 
 to it, but perfectly unheeded by those who own or drive the 
 vehicle. 
 
 The next improvement was to make the circumference of the 
 wheel as perfectly circular as the art of man could devise, and,
 
 470 NATURE'S TEACHINGS. 
 
 instead of having the wheel solid, to fill up its interior with 
 spokes, thus gaining lightness and strength at the same time. 
 
 Of all locomotive wheels, I suppose that the modern Bicycle 
 affords the best example. The driving wheel is larger than 
 the hind wheel of an ordinary coach, and yet the spokes are 
 not nearly so thick as the porcupine quill with which this 
 account is written. 
 
 If we look at the ancient sculptures and paintings of Egypt 
 and Assyria, as preserved in the British Museum, we shall see 
 that either kind of wheel was used according to the work 
 which it had to do. The solid, uneven, squeaking, wooden 
 wheel was devoted to agriculture, while the light, spoked wheel 
 was sacred either to warfare or hunting. 
 
 Let us hope that in the two latter cases some modicum of 
 grease might have been used, as the outcries of tortured and 
 unlubricated machinery are enough to drive away all wild 
 beasts which come within the range of its complaints, while the 
 nervous system of hunter or warrior must have been seriously 
 damaged by it. 
 
 EVEN in such a structure as the spoked Wheel, Nature has 
 anticipated Man. 
 
 My readers may remember that, when treating of nautical 
 matters, I mentioned the singular anchor-shaped spicules that 
 are found upon one of the sea-slugs, called Synapta. 
 
 There is another group of these creatures inhabiting the 
 Mediterranean, in which the skin-spicules take a different form. 
 Like those of the Synapta, they are too small and translucent 
 to be seen without the aid of the microscope and carefully 
 adjusted light. But, just as the spicules of the Synapta 
 resemble the ancient anchor, so do those of the Chirodota 
 resemble the ancient wheel, the similitude being in both cases 
 absolutely startling. 
 
 Not only that, but, as all readers must be aware, if they 
 have studied practical mechanics, there are many machines 
 which are toothed on the inner, and not the outer, side of 
 the circumference. Here, in the Chirodota, the inner toothing 
 is manifest. 
 
 What purpose it serves we know not. The Chirodota's 
 wheels (of which there are thousands) never revolve, neither
 
 ANTICIPATIONS OF NATURE. 471 
 
 do the anchors of the Synapta hold the ground. Yet the very 
 fact that such exceedingly minute objects should be so carefully 
 constructed tells us at once that they must have some important 
 purpose to serve, though at present that purpose is a mystery 
 which no one has attempted to solve. 
 
 I have little doubt that when the hour and the man arrive, 
 as arrive they surely will, we shall find in these tiny and almost 
 unrecognised spicules the keys to treasures of wisdom which 
 at present have been opened to no human being. 
 
 The whole history of the progress of the human race shows 
 that facts have been allowed to accumulate, fought about, and 
 turned in all directions, before the generaliser comes who 
 pierces to the heart of everything, reduces apparent dis- 
 crepancies to harmony, and usually is rewarded by finding some 
 one else assume the credit of his discoveries, and receive all 
 the honours and emoluments.
 
 USEFUL ARTS 
 
 CHAPTER XIY. 
 
 Paper and its many Uses. The Egyptian Papyrus. India Paper. China and 
 its Manufactories. Materials of which Paper is made. Annual Consump- 
 tion of Material. The " Water Mark." Nature's Papers. Wasps and 
 Hornets. The common Wasp, and the various Materials of its Nest. 
 Utilisation of Material. Papier-mache. Printing. Nature-printing. 
 Method and Results of the Process. Use of the Electrotype. " Facing" the 
 Copper Plates with hard Metal. The Coal Mine and its Nature-printing. 
 Stippling, its Use and Abuse. The Line and the Dot. Modification of the 
 Dot. Flower-petals. The Pelargonium. Plaster Castings. Stereotyping 
 and Electrotyping. Modern Method of taking Plaster Casts. The Principle 
 of Corrugation. Flower-pot Covers. Iron Buildings. The Polistes and its 
 Corrugated Dwellings. 
 
 ART. 
 
 WE will now touch lightly on the subject of Art. 
 In the present day one of the most indispensable 
 accessories to art is Paper. 
 
 It is a curious fact that we have no records as to the time 
 when paper was first invented. The Egyptian papyrus we do 
 not consider, as it was not paper in our sense of the word, 
 although we have retained the name. 
 
 Paper is a vegetable fibre carefully disintegrated, made into 
 a pulp with water, and then dried in thin sheets. As is the 
 case with many arts, China seems to have taken the lead in 
 paper manufacture, and we are even now indebted to that 
 country for the " India Paper " on which the finest proofs of 
 engravings are taken. This paper is made from the inner bark 
 of the bamboo. " Rice Paper," so called, is not paper at all, 
 but only a kind of p)th cut spirally, and flattened by pressure. 
 
 There is scarcely any vegetable fibre of which paper cannot 
 be made, and various plants have been suggested for this 
 purpose, such as the stinging-nettle, cabbage- stalks, hop-bines,
 
 PAPER-MAKING. 
 
 473 
 
 the waste of sugar-cane, sawdust, &c. Straw has already been 
 successfully used, and so has Esparto grass. 
 
 Some years ago, when there was a scarcity of material for 
 paper-making, the well-known Grass-wrack of our shores 
 (Zostera marina] was brought into partial use. I believe, 
 however, that the experiment was not a successful one. The 
 Chinese make their paper of bamboo, macerating and pounding 
 it until it is reduced to a pulp, and then shaken into fibres in 
 a mould. 
 
 With us, white paper, such as is used by the writer, printer, 
 
 NBST OP HORNET. 
 NEST OF TREE- WASP. 
 
 PAPER-MAKING. 
 PAPEB. 
 
 or artist, is made almost exclusively of cotton or linen rags. 
 Upwards of a hundred and twenty thousand tons weight of 
 rags are annually consumed in this country for the manufacture 
 of paper. After being bleached, they are torn and ground into 
 a pulp, which is then handed over to the actual maker. 
 
 The illustration represents paper-making by hand, a process 
 which is now rarely used, except for special kinds of paper. 
 Omitting technical details, the mode of paper-making by hand 
 is as follows : The pulp being prepared, the workman takes a 
 "mould," i.e. a frame with a bottom of closely woven wire.
 
 474 NATURE'S TEACHINGS. 
 
 Having put into the mould a sufficient quantity of pulp, he 
 shakes the mould so as to spread the pulp evenly over the 
 surface. The water runs away between the wires, the sheet of 
 pulp is transferred to a piece of felt, and when it is dry it 
 becomes paper. If a sheet of ordinary note-paper be held up to 
 the light, the marks of the wires are plainly perceptible. The 
 so-called " water-mark " is due to wires twisted into the 
 requisite shape. 
 
 The Chinese workman makes his paper exactly on the same 
 principle, but the bottom of his mould is made of bulrushes 
 instead of wires. 
 
 As for machine-made paper, the process seems absolutely 
 magical. Endless bands of felt and wire are substituted foi 
 the hand frames, and, the pulp being poured in at one end, 
 the finished paper is poured out at the other, and self- wound on 
 rollers. Without any exaggeration, paper is now made by the 
 mile, the only limit to its length being the size of the rolls. 
 
 WHEN I mention Paper-making in the world of Nature, 
 many of my readers will at once know that I am about to 
 refer to the Wasp tribe. 
 
 These insects were paper-makers long before even the Chinese 
 had invented the art, and, so exactly similar is the mode of 
 action, that man might well have copied from the insect. 
 
 The Wasp gnaws a bundle of vegetable fibres, mostly of 
 wood, sound or decaying, according to the species. It masti- 
 cates them until it has reduced them to a pulp, and then, by 
 means of its jaws, ^spreads the pulp into sheets of various 
 shapes and sizes. 
 
 With some of the pulp it forms hexagonal cells like those of 
 the bee, and with some it makes the roof-like covering which 
 defends the cells. Not only that, but it can make a sort of 
 papier-mache, which it uses for the flooring, if we may so call 
 it, of the different strata of cells, and for the pillars which 
 bind them together. 
 
 Like our own paper manufacturers, it is economic of material, 
 will re-masticate any superabundant paper, and is only too 
 glad if it can get hold of any paper made by man. I have seen 
 a wasps' nest which was made entirely from the empty blue 
 and white cartridges that were thrown away by soldiers.
 
 NATURE-PRINTING. 
 
 475 
 
 Then there is as much difference in the papers made by wasps 
 as in those made by man. In this country all wasps' nests are 
 made of very fragile material, but in South America there are 
 some wasps which make the external covering of their nests as 
 hard and white as the stiff cardboard employed by artists. 
 
 HAVING now got our paper, we will glance at one or two modes 
 of using it for Art. Papier-mache has already been mentioned, 
 and it is worthy of notice that there are now in existence 
 many decorated ceilings which are made of this material, on 
 account of its great strength and its non-liability to fire. 
 
 The first invention which we shall notice is that which is 
 
 FERNS IN COAL. 
 
 NATURE-PRINTING. 
 
 known by the name of Nature-printing, and which has been 
 so successful in transferring to paper an exact representation of 
 vegetable foliage. 
 
 One simple tolerably efficacious mode of Nature-printing 
 has long been known. A piece of paper being rubbed with 
 lamp-black and oil, the leaf was laid upon it and gently rubbed, 
 so as to transfer the lamp-black to the nervures. It was then 
 laid on a sheet of white paper, and again rubbed, when an 
 impression of the leaf was left upon the paper. 
 
 The present system of Nature-printing is far in advance of 
 this rather rude method, and amounts to an exact reproduction 
 of the plant, not only in form and detail, but in colour. 
 
 In order to illustrate this beautiful process, I cannot do 
 better than transfer to these pages the following account of 
 Nature-printing as given in Ure's "Dictionary of Arts," &c. 
 It is an abstract of a lecture delivered by Mr. H. Bradbury at 
 the Royal Institution. 
 
 " Nature-printing is the name given to a technical process
 
 476 NATURE'S TEACHINGS. 
 
 for obtaining printed reproductions of plants and other objects 
 upon paper, in a manner so truthful, that only a close inspection 
 reveals the fact of their being copies ; and so distinctly sensible 
 even to touch are the impressions, that it is difficult to 
 persuade those unacquainted with the manipulation that they 
 are an emanation of the printing-press. 
 
 " The distinguishing feature of the process consists, first, in 
 impressing natural objects such as plants, mosses, seaweeds, 
 and feathers into plates of metal, causing, as it were, the objects 
 to engrave themselves by pressure ; secondly, in being able to 
 take such casts or copies of the impressed plates as can be 
 printed from at the ordinary copper-plate press. 
 
 " This secures, in the case of a plant, on the one hand, a 
 perfect representation of its characteristic outline, of some of 
 the other external marks by which it is known, and even in 
 some measure of its structure, as in the venation of ferns and 
 the ribs of the leaves of flowering plants ; and, on the other, 
 affords the means of multiplying copies in a quick and easy 
 manner, at a trifling expense compared with the result, and to 
 an unlimited extent. 
 
 " The great defect of all pictorial representations of botanical 
 figures has consisted in the inability of art to represent faith- 
 fully those minute peculiarities by which natural objects are 
 often best distinguished. Nature-printing has therefore come 
 to the aid of this branch of science in particular, whilst its 
 future development promises facilities for copying other objects 
 of nature, the reproduction of which is not within the province 
 of the human hand to execute ; and even if it were possible, 
 it would involve an amount of labour scarcely commensurate 
 with the results. 
 
 " Possessing the advantages of rapid and economic production, 
 the means of unlimited multiplication, and, above all, unsur- 
 passable resemblance to the original, nature-printing is calcu- 
 lated to assist much in facilitating not only the first- sight 
 recognition of many objects in natural history, but in supplying 
 the detailed evidences of identification, which must prove of 
 essential value to botanical science in particular." 
 
 Many plans have been tried with only partial success, but 
 that which is now in operation produces the most wonderful 
 results. The plants are laid upon sheets of lead, and then
 
 STIPPLING. 477 
 
 passed through rollers, so as to leave an impression in the 
 soft metal. The electrotype then comes into play, exact copies 
 of the impression being taken by it. As the face of the 
 electrotyped plate is covered with a slight deposit of some 
 hard metal, usually nickel, a great number of copies can be 
 taken without damaging the plate. 
 
 A WONDERFULLY exact parallel to Nature-printing is seen in 
 almost every coal bed. In the coal are found impressions 
 of various leaves, mostly ferns, and so exact are they, that the 
 different species have been determined and named with as much 
 accuracy as if, instead of mere impressions, they had been the 
 fern-leaves themselves. 
 
 Indeed, if it were needed, it would be perfectly easy to take 
 electrotype plates from these impressions, and to treat them in 
 exactly the same manner as those obtained in the way which 
 has already been described. 
 
 STIPPLING. 
 
 WE now come to another branch of Art, namely, the produc- 
 tion of shadow in an engraving by means of Stippling, i.e. the 
 insertion of dots instead of lines. At one time the Stipple was 
 in great favour. Then it was almost wholly abandoned in 
 favour of the line, and now it is much used in conjunction with 
 the line, especially for the delicate shading of flesh tints, such 
 as faces, female arms, &c. 
 
 In the illustration a little stippling of a cheek is shown, the 
 dots being purposely exaggerated. 
 
 A singularly beautiful modification of the Stipple is now in 
 use. When the engraver wishes for exceptional softness of 
 shading, he does not content himself with mere dots, but, with 
 the aid of his magnifying-glass, converts each dot into a tiny 
 star with three or more rays. Thus the dots seem to melt into 
 each other, and the requisite softness is obtained. 
 
 A very good example of this star-stipple is seen in the well- 
 known print called " Coming of Age." If the face and neck 
 of the girl in the foreground be examined with a magnifying- 
 glass, the apparent dots will be seen to be stars, so beautifully 
 arranged that the projecting rays of one fuse themselves, so to
 
 478 
 
 NATURE S TEACHINGS. 
 
 speak, with those of the surrounding stars, as is shown in the 
 illustration. 
 
 WHETHER the engraver who hit upon this singularly effec- 
 tive plan took it from Nature, I cannot say, but he well might 
 have done so, had he examined the petal of a flower through a 
 good microscope. We all know the peculiar rich softness of 
 a petal, and how our very best floral artists feel the impossi- 
 bility of transferring it to paper. 
 
 The real reason for this special beauty lies in the star- 
 stippling of the petal. The whole surface of the petal is covered 
 
 PETAL OP GERANIUM. 
 
 with multitudinous projections, which are, in fact, undeveloped 
 hairs. These projections are wrinkled down the sides, and so, 
 when viewed from above, they present the curious star-like 
 appearance shown on the right hand of the illustration. 
 
 The drawing is taken from a petal of Pelargonium prepared 
 by myself. 
 
 There is yet one point in the petal which the star-stipple has 
 not touched, and probably cannot touch. I mean the slight 
 projection of the stipple-hairs, which give an effect of light and 
 shade as well as mere flat softness. 
 
 PLASTER CASTS. 
 
 WE have already mentioned the electrotype, and may now 
 come to a branch of art winch is much associated with it, 
 namely, the Stereotype.
 
 PLASTER CASTS. 
 
 479 
 
 As many of my readers may know, types are very valuable 
 articles, and must not be wasted. If, therefore, a book should 
 be thought likely to have a steady sale, much of its value would 
 be lost if the types were kept standing, inasmuch as they could 
 not be used for any other work. 
 
 In such cases the Stereotype is employed. Omitting minute 
 details, the process is as follows : 
 
 The type, ready set up, is carefully oiled. Plaster of Paris 
 mixed with water is then poured into a shallow trough, and the 
 type pressed into it. In a short time the plaster hardens, and 
 the type is withdrawn. The plaster mould is then baked, to 
 
 SHELL-CAST IX CHALK* 
 
 CAST Dt PLASTER OF PAEIS. 
 
 drive off all moisture, and type metal is poured into it. Thus 
 a solid mass is procured, instead of a number of separate pieces, 
 so that there is no danger of disturbance, and the whole block 
 can be multiplied ad libitum if needed. This process sets free 
 the types, which can be broken up and used again. 
 
 The ordinary method of taking plaster casts is nearly the 
 same as that which has been described. The object to be cast 
 is oiled, and plaster of Paris carefully applied to it. When it 
 is " set," the plaster " mould " is removed and dried. The process 
 is then reversed, the interior of the mould being oiled, and 
 plaster poured into it, so as to produce an exact reproduction of 
 the original. 
 
 IN Nature we have almost exactly the same process, although 
 it is necessarily conducted in a much slower manner.
 
 ^80 
 
 NATURE S TEACHINGS. 
 
 All who have tried their hand at practical geology must be 
 aware of the multitudinous casts of perished beings which are 
 found in various strata. Sometimes the casts are those of 
 vegetables, the original material having been decomposed, and 
 stony matter taken its place. Sometimes there are casts of 
 fishes or echini, while shells, and even insects, are found to 
 have been cast almost as perfectly as could be done with plaster 
 of Paris at the present day. 
 
 As might be anticipated, the chalk deposits are peculiarly 
 rich in these casts, the fine particles of the chalk taking the 
 place of the plaster of Paris. 
 
 In the illustrations are shown examples of casting in Art and 
 Nature. On the right hand is a cast of fruit and leaves, which 
 may afterwards be reproduced in plaster, wax, papier-mache, 
 or electrotype. On the left is shown one of the shells so 
 common in the chalk, the upper figure representing the shell 
 itself, and the lower the mould that has been formed around it. 
 
 CORRUGATED IRON. 
 
 WE have already seen that the Wasps are paper-makers. 
 We may now see how some of the Wasps have anticipated a 
 
 NESTS OF POLISTES. 
 
 COEEDGATBD IRON. 
 
 valuable invention of man, namely, the principle of corrugation, 
 whereby a thin plate gains strength. 
 
 Even a sheet of paper gains great strength by corrugation, 
 as is seen in those paper covers which are so much in use for 
 the decoration, or rather the concealment, of flower-pots. But 
 the best example that can be given of this principle is the
 
 NESTS OF POLISTES. 481 
 
 Corrugated Iron, which has come so much into use for 
 temporary buildings, such as schools, places of worship, reading- 
 rooms, &c. It is very light and very strong, and can be used 
 either for roof or walls with equal success. 
 
 BY means of certain wasps belonging to the genus Polistes, 
 Nature produces corrugated dwellings, which are made of very 
 thin materials, but which are marvellously strong in proportion 
 to their weight. 
 
 The insects belonging to this genus are all exotic, but are 
 spread over a very large surface of the earth. 
 
 So strong are the nests made by some of these species, that 
 they need no external covering, the corrugated paper supplying 
 at the same time strength and warmth, the latter element being 
 furnished by the air which is entangled between the corruga- 
 tions. 
 
 There are many species of Polistes, mostly belonging to 
 Australasia and tropical America, the latter displaying the 
 greatest variety of form and structure in the nest. 
 
 i i
 
 USEFUL AKTS. 
 
 CHAPTER XV. 
 
 Electricity, Magnetism, and Galvanism mutually convertible. The Force co- 
 extensive with Nature. Uses of Thunder-storms. Languor from Want of 
 Electricity. Frictional and Voltaic Electricity. Origin of the Name. 
 Structure of the Voltaic Pile. A simple Example of the Pile. Nerves of a 
 Frog's Leg. The Electric Shock, and how to produce it. The Electric Jar 
 and Battery. Animal Electricity. The Torpedo and Electric Eel. Struc- 
 ture of the Electric Apparatus. The Electric Spark obtained from both 
 Fishes. Channels of Electricity in the Body. The Will and the Muscles. 
 Electricity the conducting Agent. The Human Body permeated by Nerves. 
 Telegraph Wires and the Nervous System. Lightning and the Electric 
 Spark. The Electric Light and its Power. The Fire-fly, the Glow-worm, 
 and the luminous Inhabitants of the Sea. Magnetism and Diamagnetism. 
 The Electric Telegraph and the Compass. The Principle identical in both 
 Instruments. 
 
 ELECTRICITY AND MAGNETISM. 
 
 IT has long been known that Electricity, Galvanism, and 
 Magnetism are but different manifestations of the same 
 force, and that one can be converted into the other at will. 
 It is also known that this wonderful and most important 
 principle lies latent in everything, and only needs the proper 
 machinery to evoke it. 
 
 The few following illustrations are intended to show its 
 prevalence in Nature, and that human art does not create, but 
 only makes manifest a power that exists, but lies latent until 
 called forth. 
 
 Without going into details, which would occupy the whole of 
 such a volume as this, I may mention that Electricity saturates 
 all the material creation, and that even man himself is not 
 only a reservoir of electricity, but that he feels positively ill if 
 the normal amount be not supplied. 
 
 Take, for example, the hours that precede a thunder-storm. 
 We feel languid and depressed. We cannot bring our thoughts
 
 AMBER. 
 
 483 
 
 together. We are almost incapable even of bodily labour. The 
 reason is, that the portion of the earth on which we live has 
 parted with some of its electricity, and has drawn it out of our 
 bodies. 
 
 Then comes the welcome thunder-storm ; clouds overcharged 
 with electricity come to restore the balance. The lightning 
 flashes from the clouds to the earth as soon as they are near 
 enough; the rain falls, carrying with it stores of silent electricity ; 
 and in an hour or two all seems changed. 
 
 The air, which hitherto seemed to afford no nourishment 
 to the lungs, is bracing and invigorating. The nervous sys- 
 tem recovers its tension, and the brain can act without a pain- 
 ful effect. All Nature seems to put on a different aspect, 
 and brightness and vigour take the place of dulness and lan- 
 guor. 
 
 By a strange coincidence, there is just such a lack of 
 
 GALVANISING A FBOO'S LEO. 
 
 VOLTAIC PILE. 
 
 electricity as I am writing, and the barometer has rapidly sunk 
 to such a degree that a storm seems inevitable. 
 
 One of the chief difficulties in dealing with such a subject 
 as this is to know where to begin. We will, however, do our 
 best to take a general view of it, without going into details. 
 
 Many centuries ago it was well known that amber, if rubbed 
 "with a dry cloth, would first attract, and then repel, various 
 small and light substances. Indeed, the Greek word for amber, 
 namely, Elektron, has given its name to the modern science of 
 
 n2
 
 484 NATURE'S TEACHINGS. 
 
 Electricity. Many other substances, such as glass, sealing-wax, 
 &c., possess the same property. 
 
 This frictional electricity is but transient, the electric fluid, 
 if we may be allowed to use the term, being driven out by 
 main force from the material in which it was latent, just as fire 
 is procured by the friction of two dry sticks. There is, how- 
 ever, a form of Electricity called Galvanism, from its discoverer, 
 Galvani, who, somewhere about 1790, discovered that the limbs 
 of a dead frog might be excited to action by electricity applied 
 to the nerves. 
 
 Afterwards, Volta of Pavia, from whom the Voltaic Pile is 
 named, took up Galvani's discoveries, and produced electricity 
 without friction, by the contact of differently conducting 
 substances. 
 
 The right-hand figure represents the Voltaic Pile. It is 
 composed of a series of plates arranged in the following manner 
 Zinc, Silver, and Cloth, the whole being moistened with diluted 
 acid. Copper will answer the purpose nearly as well as silver, 
 and is not so costly. A very simple mode of demonstrating 
 the presence of electricity is by taking a piece of zinc and a 
 silver coin, and placing one below and the other above the 
 tongue. If the two be then brought together, a very peculiar 
 taste is perceived, and a sudden flash of light seems to pass 
 across the eyes. 
 
 The illustration represents on the right hand the Voltaic 
 Pile as at present made, and on the left are the two hind-legs 
 of a frog, with the upper part of the nerves made bare for the 
 purpose of experimenting. The dotted lines show the extent 
 of the movements of the leg when the galvanic current is 
 passed through the nerves. 
 
 Now we come to a plan whereby electricity can be accumu- 
 lated, or locked up, so to speak, and be discharged at once 
 with a definite shock instead of being poured away by degrees. 
 This can be done in many ways, the most common being that 
 which is known by the name of the Electric Jar. It is a glass 
 vessel coated within and without with tin-foil, and having a 
 metal rod passing through the cork in such a way that while 
 the lower end is in contact with the inner coating of tin-foil, 
 the other end is guarded by a ball.
 
 THE ELECTRIC BATTERY. 
 
 485 
 
 Electricity is now poured into the interior of the jar, and, 
 when contact is made between the inner and outer coatings, 
 a sudden discharge takes place. If a number of persons hold 
 each other's hands, and those who form the two extremities touch 
 the outer coating and the ball which communicates with the inner 
 coating, a sharp discharge is at once made, passing through all the 
 bodies, and inflicting a smart shock, especially at the elbows. 
 
 Similar effects can be produced with the Voltaic Battery, 
 but, as that instrument has already been figured, the Electric 
 Jar has been selected. Of course any number of such jars can 
 be connected together, and the shock will be proportionately 
 increased in intensity. 
 
 IN Nature we have several-parallels. Putting aside the 
 o bvious one of a lightning-flash, which has already been 
 
 ELECTRIC EEL. 
 
 ELECTRIC BATTERY. 
 
 mentioned, we pass to two remarkable examples of the capability 
 of animal structure to produce electricity, to store it up, so to 
 speak, and discharge it at will. Both these creatures are fishes, 
 one belonging to the Skates or Rays, and the other to the Eels. 
 
 The upper figure on the left-hand side of the illustration 
 represents the Torpedo, sometimes called the Cramp-fish, 
 Numb-fish, or Electric Ray. Fortunately for us, it is but 
 seldom found on our coasts, but it is tolerably common in the 
 warmer parts of the world. 
 
 The electric organ in this fish is double, and so large that its 
 shape can easily be recognised even through the skin. It is made 
 up of a vast number of discs arranged upon each other in columns 
 like the metallic portions of the Voltaic Pile, and separated
 
 486 NATURE'S TEACHINGS. 
 
 from each other by delicate membranes, which take the place of 
 the cloth. "When I mention that more than eleven hundred 
 columns have been found in a single Torpedo, and that each 
 column contains several hundred discs, it may be imagined that 
 the shock which such a creature can give must be a very power- 
 ful one. 
 
 The object of this power seems to be analogous to that of the 
 venomous serpent, i.e. to enable the creature to secure its 
 prey by either killing it or rendering it temporarily insensible by 
 an electric shock. As if to show that the delivery of the shock 
 is achieved by an exertion of will, observers have noticed that 
 just before the shock is delivered, the eyes are depressed in the 
 head like those of a toad when swallowing a large insect. 
 
 A STILL more powerfully electric animal is the Electric Eel 
 of Southern America. It sometimes attains a length of six 
 feet, and its electric organs are four times as proportionately 
 large as those of the torpedo. 
 
 There is no doubt as to the object of the electric power of 
 this eel, as I have often seen it kill fish, and then eat them. 
 
 When about to deliver its shock, it curves its body towards 
 the intended victim, stiffens itself, and with a sort of shudder 
 the electric fluid is emitted. The fish at which it is aimed 
 never seems to escape, but, simultaneously with the shudder on 
 the part of the Electric Eel, turns on its back and lies motion- 
 less until it is picked up by its destroyer. 
 
 Neither the Torpedo nor the Electric Eel has unlimited 
 stores of electricity. If irritated into delivering repeated 
 shocks, each discharge is less powerful than its predecessor, 
 until at last the creature is almost wholly powerless, and must 
 rest and recruit itself before it can lay up fresh stores of the 
 electric fluid. 
 
 I may add that the electric spark has been obtained from 
 both these fishes. It was only a small spark, but in such 
 experiments a small spark is as satisfactory as a large one. 
 
 WHAT are the channels by which the electric fluid is 
 transmitted through our bodies ? 
 
 They are the nerves, which convey from and to the brain a 
 subtle fluid, if it may be so called, just as the arteries and
 
 NERVES AND TELEGRAPHIC WIRES. 487 
 
 veins convey blood to and from the heart. If any of these 
 nerves be electrified, even after the death of the animal, or 
 after the separation of a limb from the body, muscular move- 
 ments are induced, and the limb moves as if instinct with life. 
 
 "Without these nerves we should be unable to feel the 
 severest shock, but they permeate the body so completely, 
 that not a part of the skin can be pricked without a nerve 
 being wounded. 
 
 It is by means of these conductors that the will is made to 
 act upon the limbs. The mind, for example, desires the legs 
 to walk, and they do so, the order being transmitted to them 
 through the nerves. 
 
 As a rule, we are unconscious of this process. But, when 
 paralysis takes place, and the nerves refuse to perform their 
 functions, the will is absolutely useless, and, however desirous 
 a man may be of walking, he cannot move a step if the nerves 
 of his legs are paralyzed. In cases where the paralysis comes 
 on slowly and in detail, the patient mostly becomes conscious 
 of the part played by the nerves, and feels that his will can to 
 a certain degree rouse the expiring powers of the nerve fluid. 
 
 This in its turn is but the conductor for another and 
 infinitely more subtle fluid, of which our space will not allow 
 us to treat, but which forms the connecting link between body 
 and spirit. Perhaps some of my readers may have seen those 
 curious preparations of the human form, when the arteries have 
 been injected with red wax, and the veins with blue wax, and 
 then the fleshy portions dissolved away by chemical means. 
 
 The result is a perfect human form, and even to the very 
 tips of the fingers and toes the blood-vessels follow the contour 
 of the body. Did we have means of injecting the nervous 
 system, we should arrive at similar results, except that the 
 nerves would be found infinitely more intricate than the veins 
 and arteries. Thus a human being is a series of human forms, 
 interwoven with each other, and mutually dependent on each 
 other. 
 
 IT is curious to see how the great discoveries of modern days 
 have but copied Nature. 
 
 Take, for example, the network of telegraphic wires which is 
 day by day spreading itself over the surface of the earth, and
 
 488 
 
 NATURE S TEACHINGS. 
 
 the parallel will at once be visible. Just as the brain transmits 
 its message to the limbs by means of the nerves, so does the 
 same brain transmit its message through thousands of miles, 
 by utilising the wires which are but the rough and coarse imi- 
 tations of the wonderful nervous system of the human frame. 
 
 THE illustration shows the parallelism as well as can be done 
 by a mere chart. 
 
 On the left-hand side is shown the manner in which a nerve- 
 group is distributed to different parts of the body. On the 
 right the railway telegraph wires are seen, and, as the reader 
 will probably remember, branch wires are carried into the 
 
 TELEGRAPHIC WIBES. 
 
 signal boxes, just as branch nerves are carried to the most 
 distant parts of the body. 
 
 I HAVE already mentioned the Electric Spark, and that it is, 
 in fact, a miniature lightning-flash, the little crackling report 
 being a miniature thunder-clap. It can be produced by fric- 
 tional electricity, or by the voltaic pile in its many variations, 
 or by animal substances alone, as in the case of the torpedo and 
 electric eel. 
 
 We now come to a modification of the spark, whereby a con- 
 tinuous current of electricity is sent through two charcoal 
 points, and inflames them with such intensity that the eye can- 
 not look upon its dazzling whiteness. There is none of the 
 yellowness about it which is so great a drawback to our arti- 
 ficial lights, whether they be gas, candle, or lamp, and which
 
 ELECTRIC LIGHT. 
 
 489 
 
 makes ladies' dresses that are really beautiful by day look dull 
 and almost ugly by night. 
 
 It is wonderful to see how the Electric Light kills all other 
 lights. The brightest gas becomes dull, and its shadow is 
 thrown on the wall which it formerly illuminated, and the 
 most delicate tints of silks and satins suddenly display them- 
 selves in the blinding whiteness of the Electric Light. 
 
 At present it is too costly to be brought into common use, 
 but its intensity is so great that serious ideas have been formed 
 of dispensing with street lamps altogether, and illuminating 
 towns with a few electric lamps placed at a considerable height, 
 and having their beams reflected downwards. 
 
 London is thought to be a specially fit subject for this mode 
 
 LIGHTNIXli. 
 
 ELECTRIC IUGHT. 
 
 GLOW-WOEM. 
 
 of lighting, as the electric beams can pierce the fogs which 
 the gas-lamp only augments, and give the traveller some hope 
 of finding his way through the most familiar streets. 
 
 IN the illustration the right-hand figure represents* the 
 Electric Light as at present in use. The upper portion of the 
 left-hand side represents the forked lightning, whose dazzling 
 whiteness is so familiar to us, even in the noon of a summer's day. 
 
 Below are shown the Fire-fly of warm climates, and the 
 Glow-worm, which, in our comparatively cool country, cheers 
 the summer evenings with its pale lamp. As to the source of
 
 490 NATURE'S TEACHINGS. 
 
 this mysterious light, which burns without producing heat 
 sufficient to be recognised by our most delicate instruments, we 
 know but little. 
 
 There are instruments so infinitely more sensitive than the 
 best thermometer, that they will record instantaneously an 
 increase of heat if a human being passes in front of them, 
 though at several yards' distance. Yet no effect is produced 
 on them by any of the Fire-flies or the Glow-worm. The 
 spectroscope itself gives little or no information, the spectrum 
 of the light being without bands or bars, and being what is 
 technically called a " continuous " spectrum. 
 
 Last year I tried numbers of Glow-worms with the spectro- 
 scope, and always with the same result. I never saw the Fire- 
 flies alive, but, no matter what may be the colour of the light, 
 the spectrum, whether of the Glow-worm or any of the Fire- 
 flies, seems to be always continuous, and so to give but little 
 information as to its source. 
 
 There appears, however, to be little doubt that animal elec- 
 tricity is the real cause of this curious phenomenon, and that 
 the force which is expended in the torpedo and electric eel, in 
 giving shocks accompanied by slight electric sparks, may 
 develop itself in these insects by producing a continuous light. 
 And just as the electric fishes can emit or withhold the shock 
 as they please, so can the Fire-flies and Glow-worms give out 
 or retain the light by which they are so well known. 
 
 Then we come to the multitudinous luminous inhabitants of 
 the sea, which, as many of my readers have probably seen, 
 convert the waves into rolling masses of living fire. 
 
 MAGNETISM. 
 
 Now we come to another condition of electrical force, called 
 MAGNETISM. 
 
 One form of it is strongly developed in the Loadstone, an 
 ore of iron. This ore has the property of turning east and 
 west when suspended freely, it attracts any object made of iron, 
 and can communicate its powers to iron by merely stroking it. 
 There is in the Museum at Oxford a splendid specimen of the 
 Loadstone, which has imparted its virtues to thousands of iron 
 magnets, and has lost none of its virtues by so doing. 
 
 All bodies are now known to be magnetic in some way or
 
 MAGNETISM. 491 
 
 other. Several, such as iron, nickel, and one or two other 
 metals, turn north and south when suspended on a pivot, hut 
 the great bulk of other bodies turn east and west, and are 
 called Diamagnetics. 
 
 As we all know, the property of turning north and south 
 has been utilised in the Compass, without which modern 
 science would be paralyzed, and travel rendered impossible. 
 
 It is worthy of notice that although the magnetic needle 
 of the compass turns to the north, i* does not do so because it 
 
 LOADSTONE. 
 
 is attracted by the north pole, but because it is repelled from 
 the east and west. 
 
 We have long known that if a current of electricity be sent 
 round a magnetic needle, the latter at once turns at right 
 angles to it. On this principle depends the Electric Telegraph. 
 When communication is made by using the handles, a current 
 of electricity is sent round the needles, and causes them to turn 
 at right angles until stopped by a little ivory pin, which pre- 
 vents them from overshooting themselves. 
 
 There is a perpetual stream of electricity passing over the 
 earth from east to west, and in consequence all magnetic bodies 
 are forced to turn at right angles, just as is the case with the 
 magnetic needle.
 
 USEFUL ARTS. 
 
 CHAPTER XVI. 
 
 TILLAGE. DRAINAGE. SPIRAL PRINCIPLE. CENTRIFUGAL 
 
 FORCE. 
 
 Systems of cultivating Ground. The Fallow System. Manuring the Ground. 
 Custom of China. Nature's Abhorrence of Waste. What becomes of Dead 
 Animals. Burying-beetles. The Scarabaeus-beetles and their Work. 
 Drainage versus Sewage. Clay Soils and Drains. The Mole, the Earth- 
 worm, Rats, Mice, and Rabbits. The Flexible Drain and the Lobster's 
 Tail. The Turbine Pump and the Ascidian. The Spiral Principle. The 
 Smoke-jack, Kite, and Wings of Birds. Centrifugal Force. Revolution of 
 Planets. The " Governor " of the Steam-engine. The Sling, Amentum, and 
 Mop. The Gyroscope, the Bicycle, and the Hoop. 
 
 O EVERAL times, in the course of this work, we have touched 
 ^ upon man's dealings with the earth, such as mining and 
 tunnelling. We will now take another side of the same 
 question, and, in connection with Tillage, consider Drainage, 
 whereby superabundant moisture is removed from the earth, 
 and Manuring, whereby the exhausted soil is renovated. 
 
 We will take this subject first. 
 
 It has long been known that it is impossible to get more out 
 of the ground than exists in it, and that when the soil has 
 been so worked as to become unproductive, there are only two 
 remedies. The one is to allow the ground to remain unculti- 
 vated for a time. It must be ploughed in deeply, as if it were 
 to be sown with a crop, and must be left to recruit itself 
 from the air. This is the now abandoned " fallow " system, 
 which used to be in full operation when I was a child. 
 
 As, however, population increased, and with it the per- 
 petually increasing demand for food, land was found to be too 
 precious to be allowed to lie fallow and idle. Then came the 
 system of rotation of crops, potato following wheat, clover
 
 THE ECONOMY OF NATURE. 493 
 
 following potato, &c. But, above all, agriculturists learned 
 that in the long-run there is nothing so cheap as manure, i.e. 
 the return to the soil by animals of the elements which these 
 animals took out of it. 
 
 On the right hand of the illustration (page 495) is shown the 
 simplest mode of enriching the soil, namely, by spreading the 
 manure on the surface of the earth, and then digging it in. 
 Any mode of thus enriching the earth is a proof of civilisa- 
 tion. No savage ever dreamed of such a thing, and I doubt 
 whether barbarians recognised the principle at any time. 
 
 Nowadays we have recognised the necessity of returning to the 
 soil in one form the elements which we have taken from it in 
 another. As usual in such arts of civilisation, the Chinese 
 have long preceded us. They waste nothing, carrying, perhaps, 
 its principles to an extent which scarcely suits our European 
 ideas. 
 
 They even utilise the little clippings of hair, to which every 
 Chinaman is almost daily subject, if he wishes to keep up his 
 self-respect in public. The barbers carefully preserve these 
 clippings, and sell them to gardeners. They are too precious 
 to be used in general agriculture, but the flower artist, when 
 he plants the seed, puts in the same hole a little pinch of human 
 hair, knowing it to be a strong stimulant to growth. 
 
 
 WITHOUT multiplying examples of artificial manuring, most 
 of which are too familiar to need description, we will proceed 
 to the methods by which Nature has for countless centuries 
 achieved the same work that Man has lately learned to under- 
 take. 
 
 Nature abhors waste, and in the long-run will prove it, 
 however wasteful may be the ways of her servants. Take, for 
 example, the case of an ordinary tree, such as an elm, an oak, 
 or a birch. In the autumn the leaves fall. In the next 
 summer scarcely a dead leaf can be found. They have been 
 decomposed by rain, dews, and gases, and have thus returned 
 to the earth more than the nutriment which they took out 
 of it. 
 
 Here man is apt to interfere. Knowing the invaluable produc- 
 tive powers of decayed leaves, he removes them as they fall, and 
 Btores them in heaps so as to form the costly, but almost indis-
 
 494 NATURE'S TEACHINGS. 
 
 pensable, " leaf mould." In so doing, however, he deprives 
 the trees of their natural nutriment, and by degrees they 
 dwindle and die. 
 
 Nature, in this case, shows her superiority over Art. 
 
 Then we have the remarkable fact that millions of animated 
 beings die annually, and no vestige of their remains is found. 
 Hyaenas and vultures might account for a few bodies, the 
 remnants of which have been found in ancient caverns. But 
 there is no hyaena which could crush the leg bones of an adult 
 elephant ; and yet I suppose that neither in Africa nor Asia 
 has any one discovered the body of an elephant or rhinoceros 
 that had died a natural death. 
 
 In the first place, there is the curious point, which I have 
 already mentioned, and which is shared by nearly every race 
 of human savages, that when an animal feels that it has 
 received its death- stroke, it accepts the conditions, withdraws 
 itself from those who yet have life in them, and yields up 
 its life as calmly as if it were but sleeping. 
 
 But what becomes of the body? As to such enormous 
 beings as elephants, the various species of rhinoceros, and 
 whales, which are as large as several elephants, rhinoceros, 
 and hippopotamus put together, I cannot say from practical 
 knowledge. 
 
 Still, as size is only comparative, the rule that holds good 
 with a small animal may hold equally good with a large one. 
 It is my lot to walk very often upon the banks of the Thames. It 
 is a charming walk at high water, but at low water there is too 
 much odoriferous mud, and there are too many dead dogs and 
 cats to make it an agreeable resort, except for enthusiastic 
 entomologists, who seem to swarm in this neighbourhood. 
 
 Scarcely has such a carcass been stranded than it is beset by 
 Burying-beetles of various kinds. Hundreds upon hundreds 
 can be shaken out of the corpse of a dog or cat, and, before the 
 next tide has come up, there is scarcely any flesh left on the bones, 
 it having been dug into the earth by the Burying-beetles. 
 
 THEN there is that wonderful family of Scarabaeus-beetles, 
 which do us invaluable service as scavengers and agricul- 
 turists. They follow the path of the caravans, and effec- 
 tively cleanse the course which has been traversed. Even
 
 THE SCARAB^EUS. 495 
 
 man is obliged to utilise as fuel the droppings of the norses, 
 cows, and camels ; but the Scarabseus goes further, collecting 
 all that man does not need, and burying it in the earth. 
 
 The instinct of the female Scarabaeus urges it to gather 
 together the rejecta, to form them into balls, placing an egg 
 in the middle of each ball, and to bury them in the ground. 
 Thus a double object is attained, the offensive substances being 
 removed from the surface of the ground, where they do harm, 
 and being transferred below the surface, where they do good. 
 
 Even the curious instinct of the dog, which leads it to bury 
 bones, &c., which it cannot consume, and which it often 
 forgets, if well fed, leaves them to be consumed by the all- 
 absorbing earth. 
 
 It is evident that, in the end, the earth must receive back again 
 that which has been taken from it. If, for example, we follow 
 the present most wasteful plan of drainage, and fling into 
 
 SCABABjECS-BBETLES. MEN MANURING OEOUND. 
 
 rivers everything which ought to be utilised on land, it only 
 gets into the sea in the end, and in the course of years is 
 decomposed, and returns to the earth in the form of gases. 
 Meanwhile, however, we have robbed the locality, deprived it 
 of the nourishment which it required, and forced ourselves to 
 supply it elsewhere at a costly rate. 
 
 So runs the cycle of creation. Sooner or later, Nature 
 will have her way, and the more we help her, the better it 
 will be for us. 
 
 OF course I do not mean to condemn Drainage, which is 
 an absolute necessity in agriculture, and a matter of life and 
 death in households. But, when rightly conducted, it only 
 signifies that water is removed from a spot which is overstocked
 
 496 
 
 NATURE S TEACHINGS. 
 
 with moisture to one where it is needed. Wet clay lands, for 
 example, which were unproductive in point of crops, and 
 injurious in point of human health, have been converted by 
 judicious drainage into fertile and healthy grounds. 
 
 This, as it will be seen, is a very different business from 
 removing from the soil the elements which rightly belong to 
 it, and which sooner or later, in some form or another, it will 
 claim and recapture. 
 
 Still, it is evident that in the progress of civilisation there 
 must be accumulations of all kinds of refuse, which savages 
 utterly disregard. Then we come to the question of the Drain 
 combined with the Sewer, and are enabled to see how the hand 
 of man, if properly directed, only follows the course of Nature. 
 
 So we undermine our towns with a complex system of drains 
 which are understood by only a very few people. For example, 
 
 TUNNEL OF MOLE. 
 
 just as a tree is only half visible, the roots being about equiva- 
 lent to the branches, London is only half visible, the subter- 
 ranean architecture being little, if at all, inferior to that of the 
 surface. 
 
 Here, again, we are met by Nature. Very few of us can 
 appreciate the extensive subterranean works which underlie 
 us, even where the hand of man has never been placed. Putting 
 aside a multitude of tiny creatures, there are, in our own country, 
 the earth-worms which pierce the ground in all directions, at the 
 same time draining and manuring it. They penetrate it with 
 their little burrows, thus admitting the air, which the earth 
 needs as much as we do, and allowing moisture to take its right 
 place. Then there are the moles, that are perpetually travelling 
 after the earth-worms, and making drainage galleries of wonder-
 
 DRAINAGE. 497 
 
 ful extent. Then there are the numerous other burrowers, such 
 as rabbits, mice, and rats, which are common everywhere, 
 besides the less plentiful foxes, badgers, and various burrowing 
 birds, all of which assist more or less in the drainage of the 
 earth. 
 
 Even bees and wasps of different kinds assist in this work, 
 the hardest soil yielding to their small, though powerful, jaws 
 and feet, and so being made, if only temporarily, able to carry 
 off the superabundant moisture. 
 
 ONE of the most ingenious modes of Drainage was that which 
 was invented by Watts, and was avowedly based on Nature. 
 He had engaged himself to carry a drain tube through, or 
 rather over, an extremely irregular bed of a river, where the 
 pipes must accommodate themselves to existing conditions. 
 
 TAIL OF LOBSTER. FLEXIBLE WATER MAIN. 
 
 The modern system of pipes not having been brought into 
 existence, Watts had to adapt himself to circumstances, and 
 did so by making his pipe on the model of a Lobster's tail, as 
 shown in the illustration. 
 
 We have already seen how the same object has been utilised 
 in warfare as a pattern for armour, but it does seem rather 
 strange that it should be employed in the tranquil arts of peace. 
 
 ANOTHER method of removing superfluous water is by the 
 TURBINE PUMP, by which the water, instead of being cast up 
 in successive jets, was flung out in a continuous torrent. Some 
 of my readers may remember the sensation which was created 
 at the first Exhibition of 1852 by the then extraordinary 
 powers of the Turbine Pump. 
 
 Yet this is, after all, nothing but an imperfect copy of the 
 now celebrated being to which human beings have been sup- 
 posed to owe their origin, namely, the Ascidian, popularly 
 
 K K
 
 498 
 
 NATURE S TEACHINGS. 
 
 known by the name of the Sea-squirt, and with very good 
 reasons. 
 
 As a rule, it keeps up a rotation of tentacles, such as is 
 shown in the illustration, acting exactly on the principle of 
 the Turbine Pump, and drawing in and discharging water with 
 a power that is perfectly astonishing in so small a being. 
 Beside this, it has the power of flinging out at once the whole 
 of its watery contents, and any one who has incautiously 
 handled a mass of Ascidians, and been drenched by them, can 
 answer with more truth than satisfaction as to the water- 
 absorbing power of the Turbine. 
 
 Then the Ascidian can do what the Turbine cannot do. In 
 the Turbine the water which is taken in must necessarily be 
 
 TtTRBIXK PUJfP. 
 
 ejected in equal proportions. With the Ascidian the same 
 thing takes place, but with the additional power of ejecting all 
 the contained water, and then beginning afresh. 
 
 There is now no doubt that the Circular or the Turbine 
 Pump is the most powerful in such cases as emptying mines of 
 the water which, in spite of all precautions, will make its way 
 in, and destroy the labours of the miners. But I merely wish 
 to carry out the object of this work by remarking that the 
 invaluable Turbine Pump is only a very inferior copy of a 
 natural pump, which existed, as far as we know, centuries 
 before Man could find his place upon this earth. 
 
 THE SPIRAL. 
 
 Ix an early portion of this work the Spiral or Screw was 
 touched upon, mostly in connection with the propulsion of
 
 THE SMOKE-JACK. 
 
 499 
 
 vessels. We will now extend it a little further, and see how 
 it is modified so as to perform other offices than those which 
 have been described. 
 
 Allusion has already been made to the Spiral or "Wedge 
 principle, but some of the illustrations were accidentally 
 omitted. I therefore introduce them here, this being a chapter 
 of miscellanea. 
 
 The "Windmill has previously been described, as has also the 
 ship's Screw, another form of which is here given. 
 
 In the centre is shown the mechanism popularly known as 
 the Smoke-jack, though it really works by means of hot air, 
 
 BIBDS' WINGS AND TAILS. 
 
 SMOKE-JACK. SHIP'S SCREW. WINDMILL. KITK. 
 
 and only becomes gradually choked by the soot which the 
 smoke by degrees deposits upon it. It is, in fact, nothing but 
 a windmill working horizontally instead of vertically, the vanes 
 being moved by the rapidly ascending heated air. So powerful 
 is the spiral pressure of this air, that in my old college days 
 at least a dozen rows of heavily laden spits were perpetually 
 turned by a single Smoke-jack. It is many years since I 
 visited my old college, and I cannot say whether the Smoke- 
 jack still exists, but, as it did its work well so long ago, I 
 presume that it does so now. 
 
 Then there is the well-known spiral ventilator set in the 
 
 K K 2
 
 600 NATURE'S TEACHINGS. 
 
 windows of workshops. Perhaps its revolution may not assist 
 the air-current, but it does, at all events, show how much 
 exhausted air has to be expelled from the room, and conse- 
 quently how much fresh air needs to be brought into it. 
 
 PERHAPS the reader may be surprised to see that the Wings 
 and Tail of a bird and a boy's Kite are placed among the 
 examples of the Spiral principle. Yet such is the fact. If the 
 reader will move up and down the wings of any bird which 
 will not bite him, he will find that there is in them a peculiar 
 screwing motion, difficult of description, but very observable. 
 
 It is mostly for want of this movement that all our attempts 
 at fitting wings to human beings have been such utter failures. 
 We can make the wings work up and down well enough, 
 but we cannot as yet impart to them the all-important spiral 
 movement. 
 
 THAT very well-known toy, the Kite, is another example of 
 the same principle which drives the screw steamer. Its " tail," 
 which need be nothing but a piece of string with a propor- 
 tionate weight at the end, keeps the Kite in a slanting posi- 
 tion, providing that the . " belly-band " be properly arranged. 
 The consequence is that the pressure of the wind acts on it 
 as on a wedge, and so drives it upwards until the combined 
 weight of itself and the string counterbalance the upward 
 pressure. 
 
 Indeed, the only object of the string is to keep the Kite at a 
 proper inclination ; and, if that object could be attained by the 
 force of gravity alone, the Kite would ascend to a height 
 nearly double that to which it can at present attain. 
 
 CENTRIFUGAL FORCE. 
 
 CLOSELY connected with the spiral principle is Centrifugal 
 Force, that marvellous power which gives to our whole solar 
 system its ceaseless movements, and may extend, as far as we 
 know, to other and vaster systems yet unknown. 
 
 Tie a ball to a string, and swing it round, and it will be an 
 exact, though rough, representation of the double power by 
 which the movements of the heavenly bodies are governed, our 
 earth being included among them.
 
 CENTRIFUGAL FORCE. 
 
 501 
 
 The string represents the force of attraction, which binds all 
 our planets to the sun, and their satellites to the planets, while 
 the force that is employed in swinging the hall represents the 
 mysterious power that issues from the sun, and gives motion to 
 the planets. The metaphor is a very homely one, but it is 
 nevertheless correct. 
 
 IN the accompanying illustration are several examples of 
 Centrifugal Force as found both in Nature and Art. On the 
 left hand we have diagrams of some of the heavenly bodies, 
 showing the revolution of their offspring, so to call them, while 
 
 CENTRIFUGAL FOECE OF HEAVENLY BODIES. CENTRIFUGAL FORCE OF "GOVERNORS" OF ENGINE. 
 
 SLING. AMliXTUM AND MOP. 
 
 on the right are seen examples of Centrifugal Force as applied 
 to human use. For convenience' sake, the illustrations have 
 been separated into two portions. 
 
 In the first of these illustrations we have the " Governor" 
 of the steam-engine, that wonderfully ingenious and simple 
 piece of mechanism which controls the force of the steam, and, 
 without the superintendence of man, acts almost as a living 
 being might. 
 
 It is composed of two heavy metal balls, hinged, as shown in 
 the illustration, to a movable collar which slides up and down 
 the central rod. "When the engine is at work the Governor 
 revolves, and the harder it works, the more rapid is the revolu- 
 tion. Consequently, as it revolves, the balls diverge and draw 
 the sliding collar up the rod. 
 
 Here lies the whole beauty of the invention. The sliding
 
 502 NATURE'S TEACHINGS. 
 
 collar is connected with the safety-valve. Thus, if the engine 
 should be working beyond its proper powers, the Governor 
 draws up the collar, and releases sufficient steam to take the 
 undue pressure off the boiler. Thus the engine may be left, 
 so to speak, to manage itself. 
 
 NEXT are shown two examples of Centrifugal Force as 
 applied in ancient warfare, namely, the Sling, which is now 
 retained merely as a boy's toy, and the Amentum, which was 
 practically a sling attached to a spear. Both weapons have 
 been superseded by the modern firearms, but the Sling is 
 really a more formidable offensive weapon, in skilful hands, 
 than is generally suspected. 
 
 A good slinger is as sure of his aim as a good rifleman, and 
 can send his missile to a wonderful distance. Were I to be 
 armed with the best pistol hitherto invented, I should be sorry 
 to fight an accomplished slinger, unless under cover. 
 
 The really tremendous power of the Sling is obtained by 
 Centrifugal Force, the weapon, with its missile, being whirled 
 in the air, and then one string being loosed with a peculiar 
 knack something like the " loose " of a good archer. In 
 consequence, the centrifugal force is converted into direct 
 force, and the missile flies directly forwards. 
 
 The Amentum is simply a cord tied to a javelin, so that the 
 thrower has the advantage of a lever, which, after all, is only 
 the conversion of centrifugal force. 
 
 The very familiar Mop, flinging off its moisture to a con- 
 siderable distance, needs no description ; but I have introduced 
 it to show the action of centrifugal force in small as well as 
 in great things. 
 
 THE next illustration shows how this very same power acts 
 upon the greatest as well as the least of objects, and enables them 
 to maintain positions which otherwise they must of necessity fail 
 to do. Take, for example, our own Earth, and its peculiar 
 position of being tilted on one side, so as to give us the alter- 
 native seasons as it flies on its annual course. 
 
 This is simply due to its own rapid revolution, which, on 
 the same principle that keeps the arrow and the rifle-ball 
 straight on their course, prevents it from altering its position.
 
 THE TOP AND THE GYROSCOPE. 503 
 
 The very same principle acts on the boys' Tops, and is shown 
 in a really remarkable manner by the professional Japanese 
 top-spinners, who will place several tops upon each other, as 
 shown in the illustration, and make them sway backwards and 
 forwards in the most extraordinary manner, sometimes being 
 all upright, and sometimes leaning almost at right angles to 
 each other. 
 
 A favourite mode of illustrating this power of Centrifugal 
 Force is by the Gyroscope, a figure of which is given on the 
 right hand of the illustration. The interior wheel is made to 
 revolve rapidly, and the effect of the revolution is to enable 
 the instrument to maintain a horizontal position, even when 
 suspended on one side, as shown in the engraving. 
 
 The power of this revolution is quite wonderful, even in a 
 small Gyroscope which can be purchased for a few shillings. 
 
 REVOLUTION OF EARTH. JAPANESE TOPS. GYROSCOPB. 
 
 It almost seems to be alive, and to insist on retaining its 
 position, in spite of all efforts to the contrary. 
 
 This principle is used in the swinging cabin of the Bessemer 
 ship, and is also employed by quoit-players in keeping their 
 missile steady as it flies towards the mark. Even the now 
 fashionable Bicycle is managed on the same principle. 
 
 As is well known to all bicycle riders, it is comparatively 
 easy to maintain the balance when the pace is rapid and the 
 wheels revolving quickly. The difficulty is, to do so when the 
 pace is slow, and the rider is deprived of the centrifugal force 
 which keeps him on his balance almost in spite of himself. It 
 is just the same with a child's hoop, which runs straight and 
 upright when it is driven rapidly, or when, for example, it 
 runs downhill. But, as soon as the centrifugal force is 
 expended, it begins to waver, loses its direction, and soon falls 
 to the ground.
 
 USEFUL ARTS. 
 
 CHAPTER XVII. 
 
 OSCILLATION. UNITED STRENGTH. THE DOME. 
 
 Connection of Oscillation with Centrifugal Force. Equality of Time in Oscil- 
 lation. The Spider. The Stone and String. Pendulum of the Clock, and 
 its Effect on the Machinery. Acceleration and Retardation. Compensating 
 Pendulums. The Metronome, and its Use in Music. A simple Metronome. 
 Value of the Instrument in War. The Escapement, and its Connection, 
 with the Pendulum. Rlode of Action. Larva of Burying-beetle. Earth- 
 worms and Serpents. Union is Strength. The Hippopotamus Rope and its 
 Structure. The Spider-web. Distinction between the Threads. Principle 
 of the Dome. The Arch, and its Connection with the Dome. Esquimaux 
 Huts. Receiver of the Air-pump, and its Power of Resistance. The Human 
 Skull and the Egg. Accidental Resemblance. The Salad-dressing Bottle. 
 The Medusa, Strobila, and Hydra. 
 
 A PORTION of our last chapter dealt of Centrifugal Force. 
 We will now proceed to another well-known power, 
 which seems to be a variation, or perhaps a division, of the 
 same power. I mean the principle of OSCILLATION, which has 
 done so much for the present state of the world. I mention 
 the connection of the two principles because it is evident that, 
 if Oscillation were continued in one direction, it would be 
 converted into centrifugal force. In fact, it can only be 
 considered as centrifugal force interrupted. 
 
 The chief point in this subject is the equal time occupied 
 by the oscillating body, no matter what may be the " arc " 
 distance through which it sways, provided that the length of 
 the line remains the same. The discovery of this principle by 
 Galileo in a church at Florence is too well known to need 
 repetition. 
 
 This principle may be observed by any one, and at almost 
 any time. The Spider at the end of its line illustrates it, and
 
 OSCILLATION. 
 
 505 
 
 so does a stone tied to a string, both of which objects are 
 shown in the illustration. 
 
 IN various departments of Art, Oscillation is absolutely 
 invaluable. We will take, for instance, the best known of these 
 examples, namely, the Pendulum, by which the movements of 
 clocks are regulated. Without some mode of regulation, the 
 works would run down rapidly, and the clock rendered inca- 
 pable of measuring time. But, in the Pendulum, we possess 
 a means of making a clock go at any desirable rate, and be 
 faster and slower at pleasure ; a long Pendulum working slowly, 
 and a short one rapidly. 
 
 How the Pendulum affects the working of a clock may be 
 seen by reference to the right-hand figure of the illustration. 
 
 OSCILLATING WEIGHT. 
 
 METRONOME. 
 
 The movements of the clock are connected with the Pendulum 
 by means of an ingenious piece of mechanism called an 
 " escapement," because it only allows the wheel shown in the 
 illustration to move one cog at each swing of the Pendulum. 
 
 Now, as in the latitude of London a pendulum which is a 
 trifle more than thirty-nine inches in length swings once in a 
 second, it is evident that, by lengthening or shortening the Pen- 
 dulum, we have the rate of the clock entirely under command. 
 
 For example, if a Pendulum be required to swing once in
 
 506 NATURE'S TEACHINGS. 
 
 two seconds, it must be four times as long as that which 
 swings once in one second, while to swing once in three 
 seconds it must be nine times as long, the length being 
 measured by the square of the time of vibration. 
 
 We are thus able to " regulate " clocks by lengthening the 
 Pendulum if they be too fast, and shortening them if they be 
 too slow. The reader will probably have remarked that the 
 conditions of the atmosphere such as heat, cold, moisture, or 
 dryness must have an effect on the length of the Pendulum, 
 and thus alter the rating of the clock. So they do, and in 
 consequence the Compensating Pendulums have been invented, 
 some of them being made of metallic rods of different powers of 
 expansion, mostly brass and steel, while others carry a quantity 
 of mercury in a glass tube near the bottom of the Pendulum. 
 
 ANOTHER familiar example of the Pendulum is the Metro- 
 nome, which is simply a Pendulum with a weight at the top as 
 well as counterpoise below the bottom, the weight moving up or 
 down so as to decrease or hasten the pace. Generally a bell 
 is added to it, which is struck at the beginning of each bar. 
 
 The exactness of its beats is perfect, as is known to all 
 musicians, and is calculated to take the conceit out of players 
 who are apt to disregard their time. I knew one lady, a really 
 good pianiste, before whom I placed my Metronome. Before 
 she had played many bars she broke down, exclaiming that 
 the horrid bell always said " ting " in the wrong place. 
 However, she soon acknowledged the value of the instrument, 
 and was glad to use it. 
 
 A very good Metronome may be made by fastening a bullet 
 to the end of a piece of tape, and swinging it backwards and 
 forwards, regulating the tape according to the time required. 
 Such a Metronome is very portable, and extremely useful 
 where the conveyance of the clockwork instrument would be 
 troublesome. Moreover, its beats can be seen by a great 
 number of persons. I have often used it myself. 
 
 Such a Metronome is used in the army, in order to regulate 
 the pace of the soldier's step, it being of the last importance 
 that the pace should always be the same. Otherwise it would 
 be impossible to calculate the time which ought to be consumed 
 in marching a certain distance, and the military calculations
 
 THE ESCAPEMENT. 507 
 
 on which depends the success or failure of a campaign would 
 be wholly upset, half an hour too soon or too late meaning 
 failure. 
 
 THE ESCAPEMENT. 
 
 As we are on the subject of the pendulum and Escapement, 
 we will say a few words about the latter piece of mechanism. 
 It is here given on a larger scale than in the previous illustra- 
 tion, so that its action may be more easily understood. 
 Whether in watch or clock, the Escapement is exactly the 
 same in principle. 
 
 First there is the escapement wheel, the circumference of 
 which is furnished with a number of very deep cogs, varying 
 as to the work which they have to do. Then there comes the 
 escapement itself, which swings on its pivot, and is regulated 
 
 LARVA OF BURYING-BEETLE. ESCAPEMENT OF WATCH. 
 
 in its oscillations by the pendulum. As it swings backwards 
 and forwards, it is evident that only one tooth of the wheel 
 can " escape," and only that in one direction. 
 
 We can reverse a steam-engine, but the man has yet to be 
 found who can reverse a clock, i.e. enable it to continue going 
 in the opposite direction. The only mode would be to enable 
 one set of cogs to flatten themselves, so as to pass the escape- 
 ment, and a second set to start up in exactly the opposite 
 direction. Or perhaps there might be two parallel escapement 
 wheels, capable of being connected or disconnected with the 
 clock at pleasure. , As, however, a reverse movement is quite 
 needless, no such invention seems to have been made. 
 
 ON the left hand is seen an example of the same principle as 
 chown in Nature. It represents a larva or grub of the Burying- 
 beetle. It has no legs available for locomotion, and yet it can 
 get along with tolerable speed.
 
 508 NATURE'S TEACHINGS. 
 
 Many years ago, when living in Wiltshire, I was much 
 struck with this fact. There had been an epidemic among 
 sheep, which killed them off so fast that the farmers would at 
 last not even bury them, but took off the skins, and left the 
 bodies to moulder as they best might. 
 
 It was very unpleasant for the farmers, but just the contrary 
 for the Burying-beetles, which simply swarmed in the deserted 
 carcasses. If one of them were tapped with a stick, hundreds of 
 these larvae came scuttling out, displaying an activity which was 
 really remarkable in creatures practically legless. 
 
 In reality this movement is achieved by an apparatus very 
 similar in its action to that of the escapement. The rings, or 
 " segments," of which the body is composed, are furnished with 
 rows of sharp points, arranged very like the cogs of the escape- 
 ment wheel. By alternately elongating and contracting the 
 body, these points catch against surrounding substances, and 
 force the creature onwards, only allowing of movement in one 
 direction. 
 
 Perhaps the reader will remember that in an earlier part of 
 this work it has been mentioned that the various worms propel 
 themselves by the same means. So do the Serpents, the 
 edges of the scales serving the same purpose as the hairs of the 
 worms and the hooks of the grub. 
 
 UNION is STRENGTH. 
 
 ON the left hand of the accompanying illustration we have 
 an example of the wonderful power obtained by uniting 
 together a number of comparatively weak objects. It repre- 
 sents a portion of the rope attached to the harpoon with which 
 the natives of some parts of Africa attack and kill the hippo- 
 potamus. 
 
 Considering that a full-grown hippopotamus weighs several 
 tons, and, in spite of its enormous size, is as active as a tiger, 
 we can infer the strength of the rope which must be needed to 
 hold such an animal when excited with rage and pain. 
 
 A few years ago the female hippopotamus at the Zoological 
 Gardens, when deprived of her cub, actually tried to leap over 
 the lofty iron barrier, and so far succeeded as to throw her 
 weight on the uppermost bar. Fortunately it was made of 
 well-wrought iron, and was only bent by her weight. Had it
 
 THE ROPE AND THE SPIDER-THREAD. 509 
 
 been made of cast -iron, like most railings, she would have 
 snapped it like glass. 
 
 Now, the fibres of which the rope is composed are individually 
 feeble, but, when they lend their strength to each other, their 
 strength is amazing. It is well shown by a lasso in my posses- 
 sion, made of the fibres of the aloe-leaf. It is scarcely as thick 
 as a man's little finger, and yet it is strong enough to resist the 
 efforts of the most powerful wild bull. I have some of the 
 separate fibres, and it is interesting to notice how fibres so 
 slight when separate should be so strong when united. Part 
 of the rope has been unlaid, so as to show the manner in which 
 it has been put together. 
 
 Towards the harpoon itself, a number of small cords laid 
 loosely side by side are used, so as to prevent the hippopotamus 
 
 HIPPOPOTAMUS ROPE. SPINNERET OF SPIDER. 
 
 from severing the rope with his chisel-like teeth, which he 
 would assuredly do if it were single. The multitudinous cords 
 become entangled among the teeth, and baffle his efforts ; but 
 still their unity is their strength ; and, though the animal 
 may sever one or two of them, the others retain their hold 
 until he dies under a shower of spears. 
 
 ON the right-hand side of the illustration is the Spinneret of 
 the ordinary garden Spider, showing the many orifices from 
 which the silken threads emerge. It is a remarkable point, and 
 one which, I believe, is seldom noticed, that the Spider can at 
 pleasure combine all these fibres into a single cord, or issue and 
 keep them separate, just as is the case with the hippopotamus 
 rope.
 
 510 NATURE'S TEACHINGS. 
 
 The latter operation may be seen whenever a large fly gets 
 into the web. The Spider darts at it, bites it, and then, ejecting 
 a loose mass of fibres, rolls it up in a moment, as in a shroud, 
 carries it off and hangs it in a convenient place, and mends the 
 broken meshes of the web. But both kinds of the cords of the 
 net are made differently from the winding-up fibres, the former 
 being fixed together, and the latter kept separate. 
 
 PRINCIPLE OF THE DOME. 
 
 WE are all familiar with Domes, especially when the Dome 
 of St. Paul's is the most conspicuous object in our metropolis. 
 Few persons, however, except professional architects and 
 builders, seem to ask themselves the principle on which the 
 Dome is constructed. 
 
 The strength of the arch is well known, and the Dome is 
 practically a number of arches, affording material support to 
 each other, and so enormously increasing the strength of the 
 edifice. 
 
 A good idea of the Dome principle may be formed by taking 
 two croquet hoops, placing them at right angles to each other, 
 tying them together at the intersection, and pushing the ends 
 in the ground. Even by this very simple arrangement consider- 
 able strength can be obtained ; but, if the hoops be sufficiently 
 multiplied to form a close Dome, it will be evident that the 
 strength will be correspondingly increased. 
 
 So strong, indeed, is the Dome, that it could be made without 
 mortar or cement, although, of course, its strength i? increased 
 by their use. A very good example of a Dome thus con- 
 structed is found in the " igloo," or snow-hut of *.he Esqui- 
 maux, which has already been described. 
 
 As to the example which I have selected, it would havo been 
 easy enough to have chosen one of the great Domes of the 
 world, such as St. Peter's at Rome, St. Maria del Fiore at 
 Florence, St. Paul's of London, or St. Genevieve or the 
 Invalides of Paris. 
 
 I have, however, selected the present example on account of 
 the thinness of its walls, the fragility of its material, and the 
 enormous pressure which it has to undergo. This is the 
 " Receiver " of the Air-pump. It is made of glass not thicker 
 than an ordinary tumbler, and yet, even when exhausted
 
 THE DOME. 
 
 511 
 
 of air, it will resist the pressure of the atmosphere for days 
 together. 
 
 When it is remembered that the Receiver is deprived of its 
 internal air, and therefore has to resist a pressure equal to 
 fifteen pounds on every square inch of its surface, it may be 
 imagined how strong the Dome is. Were the top or either 
 side to be flat, it would be crushed as soon as a vacuum was 
 formed sufficient to deprive it of the support of the air within. 
 
 A GLANCE at the illustration will show how the Receiver is 
 modelled on the same plan as the Human Skull, the outlines 
 being curiously similar. It is this formation which imparts 
 such strength to so thin a set of bones as those which com- 
 
 HUMAN SKULL. 
 
 BECE1VER OF AIR-PUUP. 
 
 pose the human skull as enables them to protect a sensitive 
 organ like the brain, on which both reason and life itself depend. 
 Eggs also form good examples of the wonderful strength 
 obtained by this principle, their thin shells protecting the yelk 
 and the white, as well as the chick through its progress to 
 maturity. 
 
 THE last subject in this chapter is a curious example of an 
 evidently accidental resemblance in form. 
 
 The figure on the right of the accompanying illustration will 
 at once be recognised as one of those Salad-dressing Bottles 
 which try to conceal by their shape the small volume of their 
 contents. 
 
 That on the left represents one of the many forms through 
 which the Medusa passes before it attains its perfect form. It
 
 512 NATURE'S TEACHINGS. 
 
 was long thought to be a separate creature, and. was known 
 under the scientific name of Strobila. Modern researches have, 
 however, made the discovery that it is one of the transitional 
 stages between the creature known as the Trumpet-hydra 
 (Hydra tuba) and the Medusa, popularly known as Jelly-fish. 
 
 The former almost exactly resembles the Hydra of our fresh 
 waters. It is a tiny transparent gelatinous bag so transparent 
 as to be scarcely perceptible, and with some thirty or forty 
 long and delicate tentacles hanging from its open end. These 
 tentacles are used in catching the minute creatures on which it 
 feeds. It is fixed, and, to use Mr. Eymer Jones's simile, looks 
 like a beautiful silk-like pencil waving amidst the water. Its 
 length is not quite half an inch. 
 
 That it should be identical with the remarkable form shown 
 
 TBCMPET-HYDRA. SALAD-DRESSING BOTTLB. 
 
 in the illustration seems impossible, but such is the case. Its 
 body becomes contracted as if tied with strings, and every 
 segment thus formed develops a set of tentacles, breaks away, 
 and swims off in the form of a Medusa. The upper segment is 
 exhibited as undergoing this process. 
 
 The figure is magnified so as to show the structure better, 
 its right length being about one-third of an inch. A full and 
 graphic history of this creature and its manifold changes may 
 be found in Mr. Rymer Jones's " Aquarian Naturalist." 
 
 It is not likely that the inventor of the Salad-dressing Bottle 
 ever saw a Hydra, but the resemblance is strangely exact.
 
 ACOUSTICS. 
 
 CHAPTER I. 
 
 PERCUSSION. THE STRING AND REED. THE TRUMPET. EAR- 
 TRUMPET. STETHOSCOPE. 
 
 The Science of Sound. Rhythmical Vibrations. The Drum. Primitive Drums. 
 The Solid and Hollow Log. The Baas Drum and Kettle-drum. African 
 Drums. Gnostic Gems and the Ashanti Drum. Tympanum, or Drum of 
 the Human Ear, and its Mechanism. An artificial Tympanum. The 
 String. The Bow and the Harp. The Harpsichord and the Zither. The 
 Bow and the Violin. The Cricket. The Vibrator, or Reed. The Jew's 
 Harp and Harmonium. The Cicada and its Song. Harmonics upon Strings. 
 The JEolian Harp. Harmonics upon the Trumpet. The Trombone. 
 Trachea of the Swan. The Ear-trumpet. The Sea-shell. The Stethoscope. 
 Savage Food. The Aye-aye. The Siren and its Uses. Echo and Whis- 
 pering Gallery. 
 
 IN a work of this nature it would be absolutely impossible, 
 not to say out of place, to give an account of so elaborate 
 a subject as ACOUSTICS, i.e. the science of Sound. Suffice it to 
 say, that all sounds are produced by the vibration of air, and 
 that the fewer vibrations, the lower is the sound, and vice 
 versa. 
 
 When such vibrations are produced regularly, they form 
 Musical sounds, but, if irregularly, the sounds can be only 
 distinguished under the term of Noise. The earliest germ of 
 music lies in certain savage races, who, as long as they can 
 maintain a rhythmical beat on any resonant substance, do not 
 particularly care what it is. A hollow tree is a splendid instru- 
 ment in their opinion, but, if this cannot be had, a dry log of 
 wood will answer the same purpose. 
 
 Some tribes, more ingenious than others, cut a deep groove 
 upon the upper surface of a log, hollow it through this groove, 
 and then hammer away at it to their hearts' content. The 
 
 L L
 
 514 
 
 NATURE 8 TEACHINGS. 
 
 next move was to cut off a section of the trunk of a tree, 
 hollow it, set it on end, and then beat it on the sides. 
 
 Lastly, some one hit upon the idea that if the open upper part 
 of the hollowed log were covered with a tightly stretched mem- 
 brane, and that if the membrane, instead of the log, were beaten, 
 the resonance would be increased. In consequence, the real 
 Drum was invented, and seems to have existed from time 
 immemorial in parts of the world so distant that they could 
 not have had any communication with each other. 
 
 Take, for example, the well-known " Bass Drum " of our 
 bands, which is shown on the right hand of the figure. "We 
 make it a very ornamental article, with frame of metal, and 
 heraldic decorations of all kinds. 
 
 Lying against it is one of a pair of Kettle-drums, such as 
 
 BONES AND DRUM OF BAR. 
 a TUBE OF EAB. d ANVIL. 
 
 b DRUM. STIKKUP. 
 
 C HAMMER. 
 
 are always seen in mounted bands. They look very easy to 
 play, but, if the reader will try a pair, he will soon find his 
 mistake. 
 
 But there are savage tribes of Western Africa who make 
 Drums of such wonderful power that their sullen roar is heard 
 for miles around, as their slow, triple beat summons the 
 tribe to arms like the fiery cross of the Highland clans. As to 
 shape, lightness, and beauty, our Drums are infinitely superior 
 to theirs, but, so far as I can gather from personal and written 
 narratives of African travellers, none of our Drums surpass 
 theirs in richness, depth of tone, and power of carrying sound. 
 
 Sometimes these Drums, instead of being mere cylinders, 
 are carved into the most strange and fantastical patterns. I 
 possess one of these curious Drums, brought from Ashanti, 
 and carved out of a solid piece of wood.
 
 THE DRUM. 515 
 
 The strange point in it is, that it represents a double head 
 carrying, after all negro fashions, a sort of vessel upon it. One 
 part of the head represents a human head (not that of a negro), 
 while the other merges gradually into an eagle's head and beak. 
 It is, in fact, a Gnostic gem, and would pass muster as such 
 if it had been engraved on chalcedony, cornelian, or other 
 semi-precious stones which are employed in the seal-engraver's 
 art. 
 
 Upon this composite head is placed the Drum itself, which 
 is also cut out of the solid block, and which, after the fashion 
 of West African Drums, has a hole on one side. 
 
 This remarkable instrument was given to me by an old 
 merchant captain, who brought it himself from West Africa, 
 and who, when I made his acquaintance, had actually painted 
 it all kinds of colours, planted it in his garden, and was using 
 the Drum as a flower-pot. Of course, as soon as it came into 
 my possession, I put it in " pickle," i.e. a strong solution of 
 alkali, brushed off the paint, and placed it in my museum, 
 where it is now. 
 
 ON the left hand of the illustration on page 514 is given 
 a sort of map or chart of the human Ear, with its internal 
 Drum, or Tympanum, as it is scientifically termed. 
 
 It is by the vibration of this Drum that hearing is made 
 possible, the vibrations of the air being transmitted to the 
 Drum by means of a beautiful bony apparatus, termed the 
 Hammer, Anvil and Stirrup. Sometimes the action of the 
 Drum is partially checked, and then the sufferer is said to be 
 "hard of hearing/* Sometimes it is broken, or its action 
 totally clogged, and then he is said to be " stone deaf." There 
 have been cases where an artificial tympanum has been in- 
 serted, and answered its purpose fairly well. 
 
 THE STRING AND REED. 
 
 IT has previously been mentioned that all sounds are owing 
 to vibrations of the air. But there are many ways of producing 
 these vibrations, and each mode gives a different quality of 
 tone. We have already seen, by means of the drum, how 
 sound is produced by percussion. We shall now see how 
 sounds can be produced by the vibrations of a String. 
 
 LL2
 
 516 
 
 NATURE S TEACHINGS. 
 
 If the string of a bow be pulled and smartly loosed, the 
 result is a distinctly musical sound, higher or lower according 
 to the length and tension of the string. Perhaps some of my 
 readers may recall the passage in Homer's "Odyssey," where 
 Ulysses strings the fatal bow : 
 
 " Heedless he heard them ; but disdained reply, 
 The bow perusing with exactest eye. 
 Then, as some heavenly minstrel, taught to sing 
 High notes responsive to the trembling string, 
 To some new strain when he adapts the lyre, 
 Or the dumb lute refits with vocal wire, 
 .Relaxes, strains, and draws them to and fro ; 
 So the great master drew the mighty bow, 
 And drew with ease. One hand aloft displayed 
 The bending horns, and one the string essayed. 
 From his essaying hand the string let fly, 
 Twanged short and sharp, like the shrill swallow's cry." 
 
 The Harp is, in fact, nothing but a magnified bow, with a 
 number of strings of graduated length and tension. Some 
 very beautiful experiments have been made on this subject by 
 the Rev. Sir F. A. G. Ouseley, Professor of Music at Oxford, 
 who stretched a string of sixty- four feet in length, and found 
 that although, when vibrating, it must produce a note, there 
 was no human ear that could distinguish it. Yet, if combined 
 with other musical instruments, it would probably do its work 
 well. The theory of the vibrations will be briefly described 
 on another page. 
 
 These vibrations may be produced in various manners. 
 The string may be pulled with the fingers, as in the harp, the 
 guitar, the zither, or even the violin, &c., in pizzicato pas- 
 sages. 
 
 The old harpsichord, now an instrument vanished into the 
 shadows of the past, pulled the strings with little strips 
 of quill, acting like the thumb-ring of the zither-player. 
 The " plectrum " of the ancients acted in the same manner, 
 and the Japanese have at the present day a sort of guitar 
 played with a plectrum. I have heard it, but cannot par- 
 ticularly admire the effect, the notes appearing to be without 
 feeling, and as if they were played on a barrel-organ. 
 
 Sometimes, as in our modern pianos, the strings are struck 
 by hammers instead of being pulled by fingers, plectrum, or 
 goose-quill.
 
 STRINGED INSTRUMENTS. 
 
 517 
 
 The most ingenious mode of causing musical vibration is the 
 Bow, which is too familiar to need a detailed description. 
 Suffice it to say that it really is a modified bow, the place of 
 the string being supplied by a flat band of horsehair, which 
 is drawn over the string, and so causes it to vibrate. In order 
 to enable the bow to grip the string, it is rubbed with resin 
 almost as often as a billiard-player chalks his cue. 
 
 Some skill is required even in producing a sound by the 
 bow. It looks as if any one could do it, but a novice, if he 
 extorts any sound at all, never rises above a squeak. "When, 
 I took my first violin lessons, nearly thirty years ago, I was 
 so horrified at the discordant sounds elicited from the instru- 
 ment, that I retired to the topmost garret of the house in 
 order not to hurt any one's feelings except my own. 
 
 JEW'S HARP. 
 
 ON the left hand of the illustration is seen a well-known 
 example of the imitation of Nature by Art. This is the 
 common Cricket, whose loud shrill call is more familiar than 
 agreeable. 
 
 Some years ago, while engaged on my " Insects at Home," 
 I gave much time to the examination of the structures by 
 which such a sound can be produced. On the under side of 
 the wing-covers, or " elytra," as they are scientifically termed, 
 are notched ridges, which, when examined with a moderate 
 power of the microscope, have something of this appearance 
 ____. The friction of these notches produces the musical 
 sound, which, as the reader will see, is exactly analogous to the 
 friction of the bow upon the string.
 
 5.18 NATURE'S TEACHINGS. 
 
 NEXT we come to the Vibrator, sometimes called the Reed. 
 It is introduced into various musical instruments, such, for 
 example, as the harmonium, the clarionet, the oboe, the 
 bassoon, and various organ pipes. 
 
 The simplest form of the Vibrator is shown in the Jew's 
 Harp, as it is popularly called, though it is not a harp, and 
 has nothing to do with Jews. 
 
 The word is really a mistaken pronunciation of " jaw's 
 harp," because the instrument is held against the teeth, while 
 its tongue is vibrated by strokes of the finger. These vibra- 
 tions affect the air within the mouth, and, by expanding or 
 contracting the mouth, the sound is lowered or raised according 
 to the laws of Acoustics. Of course, the range of notes is very 
 small, being limited to those of the common chord, and even 
 they being attainable only by a practised performer. Very 
 good effects, however, have been produced by means of a series 
 
 VIBRATING STRINGS. AEOLIAN HARP. 
 
 of Jew's Harps, set to different tones by loading the end of the 
 tongue with sealing-wax or similar substances. 
 
 AN apparatus constructed on the same principle is to be 
 found in the vocal organs of the male Cicada. If one of these 
 insects be examined on the lower surface, two curious and 
 nearly circular flaps will be seen, just at the junction of the 
 thorax with the abdomen. It is by the action of these two little 
 vibrators that the insect is able to produce a sound so loud, 
 that in calm weather it may be heard at the distance of a 
 mile. 
 
 THE accompanying illustration is, in fact, a sort of chart as to 
 the vibration of sound. 
 
 On the right is shown the JEouAN HARP, with its upper lid 
 raised, so as to show the structure of the strings. These are all
 
 HARMONICS. 519 
 
 tuned to the same note, the present D being generally accepted as 
 being most free from false tuning, and less liable for the errors 
 of " temperament." Several of the strings are an octave lower 
 than the others, but the tonic is always the same. 
 
 The instrument is placed in a current of air, generally in a 
 window, with the sash let down upon it, and the air- currents 
 set the strings vibrating in a most wonderful manner. 
 
 There is no need for human fingers to touch them, but they 
 automatically divide themselves into the component parts of the 
 common chord, and produce octaves, fifths, and thirds ad 
 infinitum. 
 
 On the left hand of the same illustration is exhibited a string 
 of the same length and tension, vibrating in two different ways. 
 The upper figure shows it divided into three portions, each 
 of which gives the fifth above the tonic, and all of which, when 
 sounding simultaneously, give a fulness and richness to the 
 tone which could only be attained otherwise by three distinct 
 instruments. All players of stringed instruments know how 
 invaluable are these harmonics, without which many passage? 
 of well-known music could not be played, and which are 
 produced by " damping," and not pressing the strings. 
 
 So, if the string be lightly touched, or damped at the 
 crossing portion at either end, the result will be that the string 
 divides itself into three portions, and all three resound 
 simultaneously. 
 
 The lower string is vibrating in thirds, having divided itself 
 into four portions. If it were damped in the middle, it would 
 divide itself into two portions, and sound octaves. 
 
 The subject is a most interesting one, but our space is nearly 
 exhausted, and we must pass to another branch of it. 
 
 IN all brass instruments furnished with a mouthpiece, and 
 not with a reed, the notes are obtained by vibrations of the 
 enclosed air, caused by the movement of the lips. They are 
 all set to some definite tonic, sometimes C natural, but mostly 
 to a flat tone, such as B flat or E flat. 
 
 Taking the ordinary military trumpet or bugle as an 
 example, we have (when we have learne:! how to play it), 
 first, the tonic. By alteration of the lips we get the octave 
 above the tonic. Then comes the fifth ; then the third, which
 
 520 
 
 NATURE'S TEACHINGS. 
 
 is, in fact, another octave ; and then a few other notes, the 
 truth of which depends on the ear of the player. 
 
 Now, all these notes are obtained by means of the lips, 
 which set the column of air vibrating, and divide it into 
 harmonics. The apparently complicated bugle-calls of the 
 army are nearly all formed from four notes only, i.e. (taking 
 C as the tonic) C G C E GK 
 
 THE Trombone, which is shown on the right hand of the 
 illustration, has the advantage of being lengthened at will, 
 and thus giving the performer a fresh tonic, and consequently 
 
 TRACHEA OF SWAN. 
 
 TROMBONE. 
 
 another series of harmonics. Valved and keyed instruments 
 have a similar advantage, the one acting by lengthening, and 
 the other by shortening, the column of air. The former 
 is infinitely the better plan, as it sets more harmonics vibrating, 
 and consequently gives a greater richness of tone. 
 
 A familiar example of this is to be found in the Ophicleide 
 and Euphonium. The former is eight feet in total length, and 
 alters its tonic by eleven keys, which shorten the column of 
 air. The latter is of the same length, but, by the employment 
 of valves, can be made sixteen feet in length. Consequently 
 the euphonium has practically killed the ophicleide, just as the 
 ophicleide killed the serpent. The cornet-a-pistons, the brass 
 contra-basso, the flugel horn, the tenor sax-horn, &c., are all 
 constructed on the same principle.
 
 THE EAR-TRUMPET. 521 
 
 ON the left hand of the illustration is shown the wonderful 
 apparatus by means of which the Swan produces its far- 
 resounding cry. The windpipe, or "trachea," as it is 
 technically named, passes down the neck, protected by the 
 bones, until it reaches the chest. There it leaves them, enters 
 the cavity of the chest, and contorts itself in such a manner as 
 to obtain greater length, just as is the case with the trombone 
 and valved instruments. 
 
 ACOUSTICS AS AIDS TO SURGERY. 
 
 WE have already seen how the air- vibrations poured in at 
 the small end of the trumpet can make resonant notes. We 
 have now to see how the reverse process can be employed, and 
 sounds poured into the larger end be conveyed to the ear. 
 
 The Ear-trumpet is a familiar example of such an instru- 
 ment, and, as it is shown in the illustration, there is no need 
 
 KAE-TE0BIPET. CONCHA OP HUMAN EAR. 
 
 of further description. It is -'rather remarkable, by the way, 
 that the length of tube does not seem to interfere with the 
 conveyance of sound, as may be seen by the speaking-tubes 
 which are now so common in private houses, hotels, and 
 offices. 
 
 I know of one church in which there is a special seat for 
 deaf persons. The reading-desk and pulpit are both fitted 
 with the large ends of Ear-trumpets. From them pass tubes 
 under the flooring, and so into the seat, where they can be 
 applied to the ear of the deaf worshippers. 
 
 ON the right hand is the " Concha," as it>is called, of the 
 human ear, which is evidently constructed for the purpose of 
 collecting and concentrating sounds. Instinctively, if we wish
 
 522 
 
 NATURE S TEACHINGS. 
 
 to hear any sound more distinctly, we place the open hand 
 behind the ear, so as to enlarge its receptive capacity, and 
 send a greater volume of sound into the ear. 
 
 The well-known experiment of holding a shell to the ear so 
 as to hear the murmur of the sea is due to the same cause, the 
 shell collecting, though in a mixed manner, all the surrounding 
 sounds, and making a murmur which really resembles the 
 distant wash of the waves upon the shore. 
 
 Then, if we examine the various animals which need acute 
 hearing, either to seize prey or escape from enemies, we shall 
 find that they have large and mobile ears, which can be directed 
 so as to catch the expected sound. The hare, rabbit, and deer 
 are examples of the latter, while the former are well repre- 
 
 SAVAOE TAPPING TREE. 
 
 SUBOEON USING STETHOSCOPE. 
 
 sented by the domestic cat, whose ears are always pricked 
 forward when she hears the scratchings of a mouse. 
 
 ANOTHER most useful appliance is the STETHOSCOPE, which 
 enables the skilful surgeon to investigate the interior of the 
 body almost as clearly as if it were transparent. It is per- 
 fectly simple, being nothing but a trumpet- shaped piece 
 of wood, formed as shown in the illustration. Sometimes 
 it is hollow, and sometimes solid, but the result is the same,
 
 THE STETHOSCOPE. 523 
 
 sound being transmitted through wood in a most remarkable 
 manner. 
 
 For example, if one end of the longest scaffolding pole be 
 slightly scratched with a pin, the sound will be distinctly 
 heard by any one who places his ear against the other end, 
 though the person who uses the pin can scarcely hear the 
 sound himself. The surgeon, therefore, places the broad end 
 of the Stethoscope upon the patient, and the other upon his ear, 
 taps more or less lightly with his fingers, and by the sounds 
 transmitted through the Stethoscope ascertains the condition 
 of the internal organs. 
 
 ON the left hand is an illustration of the mode in which the 
 Australian savage, without the least idea of the theory of 
 Acoustics, utilises the sound-conducting power of wood. If 
 he wishes to know whether or not a hollow tree is tenanted by 
 an animal of which he is in pursuit, he places his ear against 
 the tree, taps it smartly with his tomahawk, and listens for the 
 movement of the animal inside. 
 
 So delicate is this test, that it is employed even when the 
 native is hunting for the large beetle- grubs on which they 
 feed, and which are accounted a luxury even by Europeans, 
 when they have once overcome the prejudice attaching itself 
 to eating, without cookery, fat white grubs as thick and long 
 as a mao's finger. 
 
 The Aye- aye is said to eat in exactly the same manner, 
 tapping with its long finger the trunks and branches of trees 
 and, if it hears a maggot inside, gnawing it out. 
 
 MEASUREMENT OF SOUND. 
 
 OF late years we have had an instrument which enables 
 us to measure the vibrations of sound as accurately as the 
 barometer measures the weight of the atmosphere, the thermo- 
 meter the temperature, and the photometer the power of light. 
 This is the Siren, which is shown on the right hand of the 
 accompanying illustration. 
 
 To explain this instrument fully would require ten times 
 the space which we have at command, and necessitate a great
 
 524 
 
 NATURE'S TEACHINGS. 
 
 number of drawings. I will, therefore, endeavour to explain 
 its principle in as brief terms as possible. 
 
 The reader will observe that at the lower part of the instru- 
 ment there is a disc pierced with a number of holes, and that 
 above these are two dials. Below the perforated disc, and 
 therefore unseen, is a circular plate, also pierced with holes. 
 When a pipe is attached to the lower part of the instrument, 
 and air propelled through it, the disc begins to revolve, every 
 revolution being recorded by the dials, after the fashion of the 
 ordinary gas-meter. 
 
 As the pressure is increased, the air, passing through the 
 holes, assumes a rhythmical beat, which soon becomes meta- 
 morphosed into musical notes. It is evident, therefore, that, 
 
 HUMBLE-BEE. 
 
 by means of this instrument, the number of vibrations which 
 produce a definite tone can be measured with absolute accuracy 
 by any one who has an ear capable of appreciating a musical 
 note. 
 
 It is by means of the Siren that the much-disputed tonic of 
 C will be settled, the Continental and the English C being 
 greatly at variance, and even the English C having been 
 advanced almost a tone since the time of Handel. Much is it 
 to be wished that Italy, the home of song, and England, the 
 patron of song, could unite in their tonic, instead of having 
 systems so widely different that an Italian singer is at a loss 
 with the English pitch, as is an English singer with the Italian 
 pitch. 
 
 The Siren is even brought into the service of entomologists, 
 enabling them to measure by the sound the rapidity with which 
 a flying insect moves its wings. By means of this instrument
 
 ECHO. 525 
 
 we know the origin of the sharp, piercing " ping " of the Gnat, 
 and the heavy, dull boom of the Humble-bee, both of which 
 insects are given in the illustration. 
 
 Before taking leave of this subject, I may mention that the 
 instrument is called the Siren because it sings as well under 
 water as in the air, provided that water instead of air be 
 driven through it. 
 
 ECHO. 
 
 OUR last page will be given to the phenomenon called by the 
 name of ECHO, which consists in the power of solid substances, 
 whether natural or artificial, of reflecting the waves of sound 
 thrown against them, just as a mirror reflects the waves of 
 light. 
 
 Yery often the Echo is naturally formed, as shown in 
 the illustration, by rocks which cast back the sound waves 
 thrown against them. This is the case in several parts of 
 
 WHISPERING GALLRBY. 
 
 Dovedale in Derbyshire, where a pistol shot is reverberated 
 backwards and forwards in a most wonderful manner, and a 
 trumpet blast repeats itself over and over again. 
 
 At Walton Hall, the residence of the late C. Waterton, Esq., 
 there is a wonderful Echo, nearly half a mile from the house. 
 Mr. Waterton had discovered the Echo, which proceeded from 
 the walls of the house, and, having found its focus, placed on
 
 526 NATURE'S TEACHINGS 
 
 it a large stone, called the Echo-stone. Any one sitting on 
 this stone, and singing, speaking, or whistling towards the 
 house, heard every sound repeated, as if in mockery. 
 
 The celebrated Whispering Gallery in St. Paul's Cathedral 
 is nothing but an ordinary Echo, though so intensified by the 
 process of radiation, that the sound is transmitted from one 
 side of the dome to the other, just as light or heat is reflected 
 from concave mirrors.
 
 INDEX. 
 
 Aard-vark, 182, 227 
 
 Abattis, 109 
 
 Acaleph, 15 
 
 Acorn Barnacles, 90 
 
 Acoustics, 513 
 
 Acrida viridissima, 231 
 
 Actinurus, 461 
 
 Adze, 234 
 
 ^Eolian Harp, 518 
 
 Aerostatics, 436 
 
 Air-gun, 77 
 
 Aloe, 252 
 
 Amentum, 502 
 
 Amphidotus cordatus, 224 
 
 Anchor, 39 
 
 Angler-fish, 91, 416 
 
 Antherozoids, 368 
 
 Ant-bear, 100 
 
 Ant-lion, 62 
 
 Anthidium manicatum, 237 
 
 Ants, 391, 409 
 
 Ants' Nest, 214 
 
 Aphides, 391 
 
 Aphrodite aculeata, 353 
 
 Apple-parer, 456 
 
 Aquarium, 393 
 
 Archer-fish, 78 
 
 Architecture, 159 
 
 Argus Star-fish, 89 
 
 Armadillo, 189 
 
 Armour, 120 
 
 Art, 472 
 
 Artesian Well, 433 
 
 Arundinaria Schomburgkii, 28 
 
 Ascalaphus, 111 
 
 Ascidian, 497 
 
 Aspidomorpha excelsum, 198 
 
 Auger, 254 
 
 B. 
 
 Baited Traps, 97 
 
 Ball-and-socket Joint, 313 
 Balloon, 436 
 Bamboo, 28 
 
 Band Saw, 24 
 
 Barea, 147 
 
 Barometer, 444 
 
 Basket-urchin, 8Sf 
 
 Bats, 399 
 
 Battering-ram, 153 
 
 Beak of Duck, 354 
 
 Beaver, 233 
 
 Beds, 400 
 
 Bee, 220 
 
 Beroe, 15 
 
 Bessemer Process, 299 
 
 Bicycle, 503 
 
 Binocular Microscope, 287 
 
 Birdlime, 98 
 
 Blow-gun, 75 
 
 Boat, 5 
 
 Boat-hook, 44 
 
 Boatman, 12 
 
 Boiling Water, 445 
 
 Bombardier-beetle, 156 
 
 Bombyx mori, 179 
 
 Bosjesman, 308 
 
 Bot-fly, 396 
 
 Bower, 410 
 Bower-birds, 410 
 Bowsing of Rope, 318 
 Brachinus crepitans, 156 
 Bradawl, 249 
 Brocken Spectre, 295 
 Brown- tailed Moth, 180 
 Brushes, 340 
 Buffer of Train, 369 
 Bullet-making Machine, 157 
 Bunday, 69 
 Burdock, 117 
 Burial, 419 
 Burying-ants, 420 
 Burying-beetle, 507 
 Buttons, 346 
 Buttresses, 196 
 
 0. 
 
 Cache, 397 
 Callipers, 274
 
 528 
 
 INDEX. 
 
 Caltrops, 110 
 
 Camel, 424 
 
 Camera obscura, 277 
 
 Candle, 351 
 
 Carriage Spring, 363 
 
 Cassava Press, 447 
 
 Catapult, 361 
 
 Catchpoll, 104 
 
 Cathedral, 166 
 
 Centrifugal Force, 500 
 
 Cephalotus, 98 
 
 Chaff-cutter, 320 
 
 Chameleon-fly, 11 
 
 Chinese Paper Lantern, 378 
 
 Chinese Eepeating Cross-bow, 365 
 
 Chinese Stink-pot, 155 
 
 Chirodota, 470 
 
 Chisel, 232 
 
 Chcetodon, 78 
 
 Chromatrope, 305 
 
 Cicada, 243, 518 
 
 Circular Saw, 247 
 
 Cistern, 422 
 
 Clam Shell, 260 
 
 Clasp, 347 
 
 Climbing-spur, 134 
 
 Cloth-dressing Machine, 339 
 
 Club, 52 
 
 Cnidse, 371 
 
 Coffee-making Machine, 329 
 
 Coluber natrix, 106 
 
 Combs, 343 
 
 Compass, 491 
 
 Concealment, 144 
 
 Condenser, 428 
 
 Contouring-glass, 272 
 
 Coracle, 22 
 
 Cordon Saw, 244 
 
 Cork, 350 
 
 Corrugation, 480 
 
 Cossus ligniperda, 237 
 
 Crab, 261 
 
 Crab-pot, 103 
 
 Creeper, 203 
 
 Cricket, 388, 517 
 
 Crow-oyster, 348 
 
 Crushing Instruments, 320 
 
 Cuckoo-spit, 146 
 
 Culex pipiens, 9 
 
 Cupping, 330 
 
 Cuttle-bone of Sepia, 166 
 
 Cydippe, 15 
 
 D. 
 
 Daddy Long-legs, 337 
 Dagger, 58 
 Dam, 210 
 
 Dandelion Seed, 439 
 Decticus griseus, 231 
 Deer- trap, 104 
 
 Dew, 426 
 
 Diamond Drill, 459 
 Digging-stick, 223 
 Dionea muscipula, 97 
 Dipsacus fullonum, 339 
 Disguise, 147 
 Divers, 382 
 Diving-bell, 383 
 Diving Dress, 384 
 Dog-fish Skin, 265 
 Dome, 510 
 
 Doors and Hinges, 172 
 Drag, 43 
 Dragon-fly, 455 
 Dragon-fly Trachea, 370 
 Drainage, 492 
 Driver-ant, 201 
 Drosera, 100 
 Drum, 514 
 Dutch Rush, 264 
 
 E. 
 
 
 
 Ear, 515 
 Ear-trumpet, 521 
 Earth-worm, 44 
 Earwig, 261 
 Eaves, 184 
 Echeneis remora, 333 
 Echinococcus, 40 
 Echinus, 315 
 Echo, 525 
 Echo-stone, 526 
 Eel-pot, 103 
 
 Egg-hatching Machine, 395 
 Eider-duck, 401 
 Elastic.Springs, 360 
 Elateridae, 387 
 Electric Eel, 486 
 Electric Light, 488 
 Electric Ray, 485 
 Electric Tourniquet, 463 
 Electricity, 482 
 Elk, 131 
 Elk- yard, 131 
 Emperor-moth, 104 
 Epeira diadema, 87, 315 
 Equisetum, 264 
 Ermine-moth, 180 
 Escapement, 507 
 Ether Spray, 428 
 Eumenes, 311 
 Eye, 277 
 Eye of Spider, 288 
 
 P. 
 
 Fairy Martin, 169 
 Fall-trap, 140 
 Fan, 416 
 Feather Mail, 125
 
 INDEX. 
 
 529 
 
 Fencers, 317 
 File, 263 
 Filter, 352, 425 
 Fire, 412 
 Fire-fly, 489 
 Fire-guard, 419 
 Fish-hook Spicuke, 117 
 Fish-scales, 189 
 Fish-tank, 393 
 Fishing-frog, 91, 416 
 Flying Dragon, 440 
 Flying Frog, 441 
 Flying Squirrel, 440 
 Foot of Aard-vark, 227 
 Foot of Mole, 226 
 Foot of Mole-cricket, 226 
 Fork-grinders, 356 
 Fort, 129 
 Fountains, 430 
 Frog, 484 
 
 Furnarius fuliginosus, 310 
 Fur of Beaver, 186 
 
 G. 
 
 Gad-fly, 254, 406 
 
 Galleria alvearia, 151 
 
 Galleria-moth, 151 
 
 Garden Spider, 87, 345 
 
 Gecko, 334 
 
 Geometra Caterpillar, 149 
 
 Geranium, 478 
 
 Gerris, 467 
 
 Gills of Fish, 414 
 
 Gimlet, 252 
 
 Gin, 95 
 
 Girder, 193 
 
 Glow-worm, 342, 439 
 
 Gnat, 9 
 
 Goat-moth, 237 
 
 Gohy, 334 
 
 Gold-tailed Moth, 180 
 
 Goose-grass, 116 
 
 Gossamer Spider, 437 
 
 Grallina Australia, 310 
 
 Grasping Tools, 258 
 
 Grass-hlade, 250 
 
 Grass-snake, 106 
 
 Grass- wrack, 473 
 
 Grasshopper, 337, 388 
 
 Great Green Grasshopper, 231 
 
 Grindstone, 325 
 
 Gyrinus natator, 22 
 
 Gyroscope, 503 
 
 H. 
 
 Hammer and Anvil, 51/5 
 Hammock, 402 
 Hand, 450 
 Harpoon, 71 
 
 Heart or Hairy Urchin, 224 
 Hedgehog, 110 
 Hemerobius, 397 
 Hen-coop, 393 
 Hippopotamus, 508 
 Hippopotamus Tooth, 234 
 Hirundo Ariel, 169 
 Hoof of Elephant, 364 
 Hoof of Horse, 363 
 Hookah, 377 
 Hooks, 115, 398 
 Hooka and Eyea, 346 
 Hoop-shaver Bee, 237 
 House-fly, 343, 456 
 Human Spine, 369 
 Hydra, 512 
 Hydrant, 430 
 Hyuiedesmia, 117 
 Hyponomeuta padella, 180 
 
 I. 
 
 Tee, 457 
 Ice-house, 179 
 
 Ichneumon-fly, 174, 249, 338 
 Injecting Syringe, 65 
 Iris of Eye, 293 
 Ita Palm-tree, 162 
 
 J. 
 
 Janthina communis, 48 
 Japanese Fishing-rod, 460 
 Japanese Singlethorn, 1'24 
 Jaws of Crocodile, 366 
 Jaws of Pike, 105 
 Jaws of Shark, 106 
 Jaws of Whale, 355 
 
 Kedge, 41 
 Kite, 500 
 Knee-joint, 316 
 Kris, 239 
 
 Lace-wing Fly, 397 
 Lagopus vulgaris, 150 
 Lamp, 412 
 Lampern, 33o 
 Lampetra fluviatilis, 335 
 Lancet, 83, 239 
 Lappet-moth, 149 
 Laurel-bottle. 358 
 Lazy-tonga, 454 
 Leaf cutter Bees, 231 
 Leaf-insect, 149 
 Leaf-rollers, 362 
 Leech, 335
 
 530 
 
 INDEX. 
 
 Lighthouses, 207 
 Limnaea stagnalis, 6 
 Limpet, 245, 332 
 Loadstone, 490 
 Lobster, 261, 497 
 Locust, 231 
 
 Long- tailed Titmouse, 401 
 Lophius, 416 
 
 Low-pressure Engine, 429 
 Lump-sucker, 334 
 
 M. 
 
 Maelstrom, 1 
 
 Magdeburg Hemispheres, 331 
 
 Magic Lantern, 294 
 
 Magnetic Respirator, 356 
 
 Main Gauche, 73 
 
 Mangle, 324 
 
 Mangrove-tree, 143 
 
 Manuring, 492 
 
 Mare's Tail, 264 
 
 Mason Wasp, 170 
 
 Mat, 404 
 
 Meadow Orchis, 100 
 
 Measure, 267 
 
 Medusa, 372, 512 
 
 Megachile, 231 
 
 Metronome, 506 
 
 Microgaster alvearius, 174 
 
 Microgaster glomeratus, 174 
 
 Milk, 390 
 
 Mines, 443 
 
 Mining, 430 
 
 Misericorde, 120 
 
 Mole, 496 
 
 Mole-cricket, 227 
 
 Mont Cenis Tunnel, 267 
 
 Mop, 502 
 
 Mortar, 217 
 
 Moselekatze, 162 
 
 Moss, 371 
 
 Mountains, 216 
 
 Mouse-trap, 97 
 
 Movable Gas-lamp, 376 
 
 Mud-patten, 466 
 
 Mud Walls, 181 
 
 Multiplying-glass, 288 
 
 Muscles of Leg, 449 
 
 Mussel-shell, 35, 259 
 
 Myrapetra scutellaris, 184 
 
 Myrmeleo, 52 
 
 Mynnica Kirbyi, 184 
 
 N. 
 
 Nature-printing, 475 
 Nautilus, 2, 464 
 Xeedle-gun, 367 
 Nemertes Borlasii, 93 
 Nerves, 485 
 
 Net, 85 
 
 Northern Crown, 297 
 Norton Tubes, 433 
 Notonecta glauca, 13 
 Nshiego Mbouve, 160 
 Nut- crackers, 321 
 Nuthatch, 256 
 
 O. 
 
 Octopus, 463 
 Odynerus murarius, 170 
 CEstrus bovis, 254 
 Ophion, 174 
 Optics, 276 
 Orchis mono, 100 
 Oscillation, 504 
 Ostracion, 122 
 Orang-outan, 161 
 Oven-bird, 310 
 Owl's Eye, 284 
 
 P. 
 
 Paddle-wood Tree, 198 
 Paint, 219 
 Palm-leaf, 41* 
 Paper, 472 
 Parachute, 438 
 Parasol, 407 
 Pea-shooter, 74 
 Pelecinus, 338 
 Pelicans, 393 
 Pelopceus, 312 
 Pendulum, 505 
 Pensile Oriole, 402 
 Perfume Spray, 428 
 Periwinkle, 245 
 Phantasmascope, 30-5 
 Philetaerus socius, 135 
 Pholas dactylus, 200 
 Phryganea, 192 
 Physa fontinalis, 8 
 Physalis pelagicus, 46 
 Pichiciago, 123 
 Piddock, 200 
 Pied Grallina, 310 
 Pill Millipede, 123 
 Pincers, 258 
 Pinna pectinata, 35 
 Pinna-shell, 35 
 Pistolograph, 361 
 Pitfall, 50 
 Plane, 235, 250 
 Pneumatic Peg, 330 
 Poison, 62 
 Polar Bear, 137 
 Polistes, 481 
 Polynoe, 71 
 Porches, 183 
 Porcupine, 110
 
 INDEX. 
 
 531 
 
 Porcupine Ant-eater, 110 
 
 Porthesia auriflua, 180 
 
 Porthesia chrysorrhoea, 180 
 
 Portuguese Man-of-war, 46, 372 
 
 Pouch-shell, 2 
 
 Pressure of Atmosphere, 329 
 
 Printing-press, 317 
 
 Proboscis of Fly, 379 
 
 Processionary Moth, 180 
 
 Projectiles, 74 
 
 Propolis, 220 
 
 Pseudoscope, 287 
 
 Ptarmigan, 150 
 
 Pucunha, 76 
 
 Puff and Dart, 75, 351 
 
 Pulley, 452 
 
 Pyramids, 216 
 
 a 
 
 Quilt Armour, 126 
 
 R. 
 
 Radius, 194 
 
 Rain-cloud, 429 
 
 Ranjows, 109 
 
 Rat-tail Maggots, 385 
 
 Rattan, 204 
 
 Razor, 236 
 
 Receiver of Air-pump, 511 
 
 Reduvius personatus, 146 
 
 Reed, 518 
 
 Reverted Spikes, 102 
 
 Ribbon Saw, 244 
 
 Ring and Staple, 415 
 
 Ringed Tissues, 378 
 
 Robber-crab, 405 
 
 Rocket, 462 
 
 Rod and Line, 90 
 
 Rolling-mill, 322 
 
 Rosemary, 408 
 
 Sabella, 218 
 
 Saddle-back, 348 
 
 Sailing Raft, 5 
 
 Salad-dressing Bottle. 511 
 
 Sand-paper, 265 
 
 Saturnia pavonia minor, 104 
 
 Saw, 239 
 
 Saw-fly, 241 
 
 Sawyer-beetle, 248 
 
 Scale Armour, 123 
 
 Scales of Butterfly's Wings, 187 
 
 Scaling-fork, 133 
 
 Scarabaeus, 494 
 
 Scissors, 228 
 
 Screw, 498 
 
 Sea-anemone, 8 
 
 Sea-basket, 89 
 
 Sea-mouse, 353 
 
 Sea-urchin, 315 
 
 Seed-drills, 336 
 
 Sepia officinalis, 167 
 
 Serpula, 44, 135, 219, 352 
 
 Sewage, 496 
 
 Sewing, 406 
 
 Shark-tooth Sword, 66 
 
 Shears, 228 
 
 Sheep-fly, 396 
 
 Shell of Tortoise, 188 
 
 Ship- worm, 200 
 
 Short-tailed Manis, 124, 188 
 
 Sialis armata. 275 
 
 Siamese Link, 448 
 
 Silkworm, 158 
 
 Silkworm Cocoon, 179 
 
 Siren, 523 
 
 Sirex gigas, 252 
 
 Skidor, 466 
 
 Skip-jack Beetle, 387 
 
 Skull, 210, 511 
 
 Slates, 188 
 
 Sling, 502 
 
 Sloth, 398 
 
 Slug, 245 
 
 Smoke-jack, 499 
 
 Snow-house of Esquimaux, 163 
 
 Snow-house of Seal, 163 
 
 Snow-shoe, 464 
 
 Spade, 223 
 
 Spear, 58 
 
 Spectroscope, 297 
 
 Spider, 509 
 
 Spider-crab, 147 
 
 Spiked Defences, 107 
 
 Spiracles of Fly, 357 
 
 Spiral, 498 
 
 Spiral Spring, 371 
 
 Spiral Tissues. 375 
 
 Spirit-level, 271 
 
 Spokeshave, 236 
 
 Spout-hole, 434 
 
 Sprat-sucker, 71 
 
 Spring, 430 
 
 Spring-bow, 142 
 
 Spring-gun, 142 
 
 Spring-jack, 386 
 
 Spring Solitaire, 371 
 
 Spring-tails, 388 
 
 Spring-trap, 95 
 
 Squirrel, 4o6 
 
 Stag-beetle, 248 
 
 Star-fish, 332 
 
 Steam-blast, 443 
 
 Steelyard, 450 
 
 Stereoscope, 28 ft 
 
 Stereotype, 479
 
 532 
 
 INDEX 
 
 Stethoscope, 522 
 
 Stickleback, 218 
 
 Still, 425 
 
 Stinging Jelly-fish, 372 
 
 Stinging-nettle, 67 
 
 Stipple, 477 
 
 Stoat, 150 
 
 Stone-fly, 192 
 
 Stopper, 350 
 
 Stove, 413 
 
 Stratiomys, 11 
 
 Stratiomys chamaeleon, 11 
 
 String, 515 
 
 Subterranean Dwelling, 213 
 
 Suckers of Cuttle-fish, 332 
 
 Suckers of Water-beetle, 332 
 
 Sucking Eggs, 445 
 
 Sucking-fish, 333 
 
 Sucking Sugar-cane, 445 
 
 Sumpitan, 75 
 
 Sundew, 100 
 
 Surgical Cradle, 405 
 
 Suspension-bridge, 202 
 
 Swallow-tailed Butterfly, 468 
 
 Sword, 56 
 
 Sword-grass, 57 
 
 Synapta, 40, 470 
 
 Synovia, 454 
 
 T. 
 
 Tachina, 172 
 
 Tail of Scorpion, 66 
 
 Tailor-bird, 406 
 
 Tearing Weapons, 112 . 
 
 Teazle, 339 
 
 Teeth, 327 
 
 Telegraph, 487 
 
 TerebeUa, 218 
 
 Teredo, 200 
 
 Termite, 153, 182, 394 
 
 Thaumatrope, 302 
 
 Thigh-bone, 314 
 
 Thornback-crab, 147 
 
 Throwing-stick, 79 
 
 Ties, 194 
 
 Tiger-beetle, 134 
 
 Tiger-claw, 112 
 
 Tiger-moth, 403 
 
 Tiles, 187 
 
 Tillage, 492 
 
 Tipula, 337 
 
 Toggle, 316 
 
 Tools, 222 
 
 Tools of Measurement, 267 
 
 Top, 503 
 
 Torpedo, 485 
 
 Tortoise, 229 
 
 Toucan, 346 
 
 Trachea of Animals, 380 
 
 Trachea of Insects, 376 
 Trap-door Spider, 175 
 Traveller's Tree, 423 
 Tree-caddis, 111 
 Trench, 150 
 
 Trichiosoma lucorum, 242 
 Tripod Wheel-bearer, 461 
 Triquetra, 219 
 Troglodytes calvus, 160 
 Trombone, 520 
 Trunk-fish, 122 
 Trypoxylon aurifrons, 312 
 Tunnel, 168, 199 
 Turbine Pump, 497 
 Turkish Bath, 426 
 Turtle, 229 
 
 U. 
 
 TTlna, 194 
 Umbrella, 407 
 Useful Arts, 308 
 
 V. 
 
 Vallisneria Plant, 38 
 Varnish, 219 
 Velella, 2 
 
 Venus Fly-trap, 97 
 Vertebra? of Snake, 314 
 Victoria Eegia, 196 
 Violet Snail, 48 
 Voltaic Pile, 484 
 
 W. 
 
 Walls, 177 
 Walrus, 41, 136 
 Waraus, 162 
 Wart-biter, 231 
 Wasp, 474 
 Wasp-comb, 167 
 Water-boatman, 13 
 Water-fall, 431 
 Water-enaat, 467 
 Water-lily, 382 
 Water Main, 497 
 Water-ram, 434 
 Water-snail, 6 
 Water-spider, 383 
 Water-tank, 423 
 Water Telescope, 291 
 Water Turbine, 463 
 Wax, 220 
 Wax-moth, 151 
 Weaver-bird, 169, 185 
 Webbed Feet, 467 
 Wet-bulb Thermometer, 428 
 Wheat Straw, 27
 
 INDEX. 
 
 533 
 
 Wheel, 469 
 
 Wheel Animalculse, 306 
 Whelk, 245 
 
 Whirlwig-beetle, 22, 292 
 Whispering Gallery, 526 
 Wind, 442 
 Window, 190 
 Woodpecker, 256 
 
 Woolly Bear, 110 
 Wurble-fly, 396 
 
 . 
 
 Zarabatana, 76 
 Zoetrope, 305 
 Zoster a marina, 473 
 
 THE END. 
 
 riUNTliD BY J. S. VIRTUE ANH CO- UM1TBD. CITY ROAD, LONDOM.

 
 UC SOUTHERN REGIONAL U8HARY FAdUTY 
 
 A 000 048 045 9