Triumphs & wonders of modern chemistry, a popular treatise on modern chemistry and its marvels, written in non-technical language for general readers and students

Front matter

TRIUMPHS AND WONDERS OF MODERN CHEMISTRY

TRIUMPHS & WONDERS

OF

Preface

Within the last few years Chemistry has been revolutionised by startling discoveries which have followed one another in quick succession, and these are briefly described in the following pages. The atoms have been shown to be of immense complexity, the seat of vast forces and terrific motions, the very existence of which was, scarce dreamt of until the advent of radium. A series of magnificent researches has recently shown us that these atoms, far from being the changeless and eternal foundation stones of the Universe that they were once thought to be, are themselves crumbling away. Such conceptions and discoveries have altered the whole aspect of chemistry, and have necessitated the treating afresh of many old problems previously regarded as settled. It has been my lot while lecturing on Chemistry to have come into frequent contact with many thoughtful men and women, boys and girls, who have felt much interest in this new chemistry, which has arisen out of the old, and who have wished to know something more of the grand questions of the day touching the ultimate nature and constitution of the Universe in which they live, and of the matter which surrounds them on every side in untold millions of tons, but who have neither the leisure nor the inclination to master the technicalities and enter into the minutiae of the regular textbooks of Chemistry where such things are discussed. These text-books, moreover, labour under the disadvantage that they are written for candidates studying for one or other of the innumerable examinations in which our University authorities take such a keen delight, and which, combined with a complete lack of educational freedom, make an English University Student's life a perfect nightmare to him (in sad contrast to that of a German or American Student),

vii viii PREFACE

and destroy rapidly and effectively any genuine interest in Science that he may have possessed at his entrance to the University, besides exercising a paralysing effect on the University Lecturers themselves, and diminishing greatly the output of research work in this country, to its incalculable material and moral harm.

This book is not written for examination candidates. It is written in order to awaken the interest of the general reader and the young student in what is after all a grand science ; for Chemistry is the Science which tells us that Nature works by unseen bodies — by myriads of tiny atoms whirling in gigantically swift and infinitely complex motion, the whole forming a microcosmic world beneath the visible world — and that her true laboratory consists of " events in inconceivable numbers, the whole phantasmagoria of these events changing every instant down to its minutest details with inconceivable rapidity.'' The most insignificant objects are fraught with endless wonder and mystery. A breath of wind is the swift rush of millions of atoms, the blazing of a match the destruction of a universe almost infinite in complexity and the building up of a new one out of its ruins, while in the tiniest grain of dust dancing in a sunbeam the rush of atomic events in the millionth part of a second is so incredibly swift as to defy all conception and calculation. Indeed, the whole universe, from its uttermost heights to its deepest depths, is but one vast system in a state of ceaseless and stupendous chemical change., This book represents an effort to give the general reader a picture of the world in which the chemist wanders, and an idea of the great and wonderful problems with which modern chemistry deals. At the same time it is hoped that the book will prove useful both to popular lecturers and to Chemistry teachers in need of interesting illustrative facts for their routine chemical classes.

Every care has been taken to keep the subject matter as thoroughly up-to-date as possible. In every case the most recent authorities, not only English but foreign as well, have been consulted, and references are given to much of the original literature for those who wish to pursue the subject further. No one authority has been slavishly followed, but

PREFACE ix

an endeavour has been made to put every fact in a fresh and original way. Indeed, the reader will find several new views published here for the first time, while many old problems have been presented in a novel form and treated on lines different from those usually adopted in the ordinary chemical text-book. Part of my object has been to break away from the stereotyped text-book style, without thereby sacrificing scientific exactitude and precision. By such means I hope to bring the reader into immediate contact with the thoughts of the great leaders of science, whose ideas, usually buried away in the transactions of learned societies, are inaccessible to all but the specialist.

My searchings in the original memoirs and addresses of the great leaders of chemical thought have been very extensive, and represent a labour extending over some years. If, however, I succeed in awakening the interest of the intelligent reader in our science, such labour will not have been in vain.

On every doubtful point I have not hesitated to consult with leading authorities who have made a special study of the subject, and so I hope that few errors will have crept into the following pages, and that the views presented will be in accordance with the most recent results of scientific research.

My best thanks are due to Dr. Henry J. S. Sand, Ph.D., D.Sc, whose deep and exhaustive knowledge of the most difficult developments of Modern Chemical Science was ungrudgingly placed at my disposal in writing this book. Almost every page has been benefited by his criticism and advice.

I am much indebted to Sir William Crookes, F.R.S., for his kindness in revising the chapter on Nitrogen and our Food Supply, to which he appended some observations and corrections, which are all the more valuable since they come from the eminent chemist who first called the attention of the scientific world to this great problem in his famous address to the British Association.

To Mr. Frederick Soddy, M.A., I am indebted for information and corrections on the radio-active elements — a subject on which his researches have become classical. To Dr. Caven, D.Sc, F.I.C., I am indebted for some manuscript notes, which have enabled me to treat some portions of the x PREFACE

subject in an original manner. Mr. Golding, F.I.C., of the Midland Agricultural College, Kingston, Derby, was kind enough to allow me to reproduce photographs illustrating his experiments on " Nitrogen-fixing " organisms ; I have also to thank him for advice and information on this subject.

My best thanks are due to Mr. Prichard, of the Nottingham Library, for the trouble he took in looking up books and records for certain information ; also to my wife for many suggestions, useful criticism, and active help.

Among other authorities with whom I have had occasion to correspond while preparing this book may be mentioned : Miss Ida Freund, of Girton College, Cambridge, who gave me some information regarding Lucretius' Poem " De Rerum Natura" ; Mr. W. C. D. Whetham, M.A., F.R.S., who gave me leave to use part of his book, " Recent Developments of Physical Science " ; Mr. Edwin W. Streeter, who allowed me to quote from his work on " Precious Stones " ; Mr. J. E. Gore, F.R.S., who revised some of the astronomical statements made in the early parts of the work, and who gave me permission to quote from some of his works on Modern Astronomy ; Mr. Kipling, who gave me leave to quote from his poem " Sea-Cables " ; Sir William Ramsay, F.R.S., who corrected some statements regarding his researches; Mr. Edw. A. Oates, British Vice-Consul at Porto Empedocle, Sicily, who procured for me illustrations of the Sulphur District, Girgenti, Sicily ; Bryant & May, who gave me information on Match Manufacture; Siebe, Gorman & Co., who gave me information and illustrations regarding their oxygen apparatus. Among the firms who have allowed me to quote from some of their publications may be mentioned : Kegan Paul, Trench, Triibner & Co. ; The Cambridge University Press ; Macmillan & Co. ; The Proprietors of Cassier's Magazine ; Harper Brothers ; Seeley & Co. ; Grant Richards ; Methuen & Co.; John Murray; Smith, Elder & Co. ; The English Illustrated Magazine ; The Strand Magazine ; The Forum. To all of these I return my best thanks.

Geoffrey Martin.

Birkbeck College,

Chapter I Page

Eternal Circulation of Matter in the Universe — Indestructibleness of Matter — Theories of Matter — The Ether — Osborne Reynolds' Theory of Matter — Electronic Theory of Matter — Is Matter really Indestructible ? — Nature of Mass — Amount of Matter in the Universe i

Chapter II

The Universe in a State of Flux — Atomic Theory of the Greeks — Lucretius' Poem, " De Rerum Natura " — Newton's Views on Atoms — Dalton's Atomic Theory — Avogadro's Work — Molecules — Magnitude of Molecules — Molecular Science and Living Matter — Molecular Speeds — Vast Speeds prevailing within the Molecules — Possibility of seeing Molecular Motion — The Ultramicroscope and its Wonders — The Shapes of Atoms — Pasteur, Le Bel, and van't Hoff's Work — Optical Activity .......... n

Chapter III Distribution And Evolution Of The Elements

What is an Element ? — What the World is made of — Distribution of the Elements in Space — What Meteorites teach us — Cosmical Dust — The Interior of the Earth probably Metallic Iron — The Crust of the Earth — Unequal Distribution of the Elements probably due to Evolution — How the Elements came into Being — Thomson's Electronic Theory — The Proto-Elements — Will the light Elements all turn into heavy ones ? — The World's Future — Stellar Evidence for the Evolution of

xi xii CONTENTS

PAG*

the Elements — Lockyer's Work — Arrhenius' Views — The Laboratories of the Universe — Vastness of Nebulas — Chemical Changes going on in Nebulae and Stars — Enormous Temperatures and Pressures prevailing in the Depths of the Sun and Stars — Gigantic forces prevailing in their Depths — Probable Formation and Decomposition of Elements in Stars and Nebulas — Human Chemistry necessarily of very limited Scope — The Disintegration of the Elements — Radium — Energy residing within Matter Atoms — The Universe Eternal — Arrhenius' Views — Herbert Spencer's Views . . 31

Chapter IV

The Wonders of Chemical Combination — Chemical Forces probably electrical in Origin — Vast Magnitude of Chemical Forces — Why Atoms when they unite cause the Evolution of Heat and Light — Swiftness of Atomic Events — Johnstone Stoney's Views on Molecular Collision — Chemical Forces Supreme in the Universe — Chemical Symbols and Equations — A Chemical Change a Molecular Catastrophe — Structure of Molecules — Fournier d'Albe's Speculations • 55

Chapter V

Antiquity of the Ocean — Origin of the Ocean — Early Condition of the Earth — Water exists in Neighbouring Planets — The Ocean sinking into the Crust of the Earth — Future Fate of the Ocean — Water inJLiving Matter — Circulation of Water over the Earth — Water evolved by Vegetation — Chemical Composition of Water — How Water freezes — Influence on the World — Ice — Gaseous Water — How Water boils — Effect of Temperature on the Properties of Water 82

Chapter VI

Early History of Hydrogen — Preparation — Explosions in Iron Smelting due to Hydrogen — Explosion of a Warship's Boiler due to Hydrogen — Hydrogen and the

CONTENTS xiii

PAGB

Evolution of the Elements — Prout's Hypothesis — Hydrogen in Space — Vast Hydrogen Flames on the Sun — Hydrogen on Stars — Hydrogen and Exploding Worlds — Hydrogen in Water — Hydrogen in the Air — Balloons — Glaisher's and Coxwell's Ascents — Tragedies of the Air — Properties of Hydrogen — Liquid Hydrogen — Dewar's Researches — Structure of Hydrogen Gas — Hydrogen Atoms enormously complicated Structures . . . 107

Chapter VII

The Mystery of the Air — Properties of Air — Why Air is invisible — How the Air protects us from the Awful Cold of Space — How it protects us from Meteorites — Height of the Atmosphere — Circulation of the Atmosphere — The Aurora Borealis — Composition of the Air — Aqueous Vapour in the Air — Clouds — Carbon Dioxide and Ozone in the Air — The Upper Regions of the Atmosphere consist of Hydrogen and Helium — Dust in the Air — The Wonders of Dust — Cosmic Dust — Molecular Structure of Air — Liquid Air and its Wonders — Solid Air — Action of Great Cold on Living Matter — Bacteria are not killed by Intense Cold — Arrhenius' Theory of the Spread of Life in the Universe by Means of Radiation Pressure — Past and Future Changes in the Composition of the Atmosphere — How Oxygen got into the Atmosphere — Ultimate Fate of the Atmosphere — The Atmospheres of other Worlds — Johnstone Stoney's Theory of Planetary Atmospheres — Atmosphere absent from the Moon — Atmosphere of Venus — Atmosphere of Mars — Atmospheres of Jupiter, Saturn and Neptune — The Sun's Giant Atmosphere 126

Chapter VIII

All Living Matter ceaselessly combining with Oxygen — How Oxygen combines with the Blood — Nature of Haemoglobin — Oxygen essential to Animal Life — Effects of withdrawing the Oxygen from the Air — Astonishing Properties of Oxygen — Life in an Atmosphere of Pure Oxygen — Liquid Oxygen — Molecular Structure of Oxygen — Uses of Oxygen — How Oxygen has saved Lives in Exploded Mines — The Courrieres Disaster — The Hamxiv CONTENTS

PAGE stead Disaster — How Mr. Fleuss saved the Severn Tunnel by means of Oxygen — Oxygen for Athletes — Reviving Power of Oxygen — Preparation of Oxygen from Potassium Chlorate — The largest Preparation of Oxygen on Record — Manufacture of Oxygen from the Air by Linde's New Process — Vast Mass of Oxygen in Nature — Oxygen in the Crust of the Earth — Ozone — Explosive Properties of Ozone — Energy in Ozone — Ozone as a Cosmical Agent for trapping Energy — An Ozone Planet 165

Chapter IX

Chemical Inertness of Nitrogen — Preparation of Nitrogen — Properties of Nitrogen — Life on a Nitrogen World — Energies locked up in Nitrogen — How Lightning combines Nitrogen — Nitrogen in Living Matter — Nitrogen chemically combined in the Soil essential for Fertility — Our Food Stuffs depend upon the Nitrogen fixed in the Earth — Exhaustion of Nitrogen in Cultivated Lands — Manures — Sodium Nitrate or Chili Saltpetre — Approaching Exhaustion of the Saltpetre Beds — Problem of Fixing Atmospheric Nitrogen — Crooke's Work — Nitrifying Organisms — Nobbe and Hiltner's Nitragin — Birkeland and Eyde's Nitrogen-fixing Factory at Notodden in Norway — Professor Franke's Method of Fixing Atmospheric Nitrogen — Nitrolime — Cyanamide — Artificial Urea and Guanidine — Artificial Creatine — Will our Food be made in the Future in Chemical Laboratories? — Circulation of Nitrogen in Nature . . . • i8q

Chapter X

Power used in Modern Civilisation depends upon Carbon — Amount of Carbon in the Rocks — In Coal — In the Sun and Stellar Regions — Carbon in Living Matter — Diamonds^ — Infusibility of Carbon — How Carbon can be Melted — Artificial Diamonds — Moissan's Work — Origin of Diamonds — How the South African Diamond Mines were discovered — Description of the Kimberley Mines — Strange Life History of the Diamond — How Diamonds burst — Diamonds and Coal identical — How Diamonds burn — The Story of some Wonderful Diamonds —

CONTENTS xv

PAGB

Graphite — Where Graphite is found — How Graphite is manufactured — Charcoal and its Wonderful Structure — Coal and its Wonderful Story — Kingsley's Description of a Coal Forest — General Properties of Carbon — Its Chemical Affinities — Astonishing complexity of Carbon Compounds — Cellulose, the Skeleton of Vegetable Life — The Sugars — Albumen — Camphor — Indigo and other Dyes — Wonders of the Atomic Structure of Carbon Compounds 206

Chapter XI

How Coal burns to an Invisible Gas called Carbon Dioxide — How to prepare Carbon Dioxide — Its curious Properties — Dangers of Carbon Dioxide — Evolution of Carbon Dioxide from the Earth— The Death Valley of Java— The Death Gulch of America — Carbon Dioxide Fountains around the Laacher Sea — The Grotto del Cane — Evolution of Carbon Dioxide from Vesuvius and Volcanoes — Evolution of Carbon Dioxide from the Earth in Past Ages — The Volcanic Eruption in Iceland in 1783 — Suffocation of the Elder Pliny by Carbon Dioxide evolved from Vesuvius — Evolution of Carbon Dioxide from Garden Land — Accumulation of Carbon Dioxide in Old Wells and Vaults — Evolution of Carbon Dioxide from Living Creatures — From burning Coal — From Volcanoes — Absorption of Carbon Dioxide by the Rocks in the Process of Weathering — Vast Amounts of Carbon Dioxide chemically combined in Limestone and Chalk — Absorption of Carbon Dioxide by Plants and its Decomposition into Oxygen by their Agency — Vast Amounts of Energy poured forth from the Sun into Space — Plants a Means of Fixing Part of this Energy — Circulation of Carbon in Nature — Carbon Dioxide steadily accumulating in the Atmosphere — The Climate must improve in consequence — Changes in the Earth's climate in Geological Times probably due to varying amounts of Carbon Dioxide in the Air — Much Carbon Dioxide in Air produces a warm Climate and a Luxurious Vegetation — Solubility of Limestone in Water containing Carbon Dioxide in Solution — Hard and Soft Water — Wonderful Limestone Caverns — The Limestone Caves of Carniola — Dr. Schmidl's Explorations of Under- J ground Caverns — The Cave of Caripe in Venezuela — Grotto of Adelsburg — The Mammoth Cave — Lake of Zirknitz — Earthquakes due to the Collapse of Underground Caverns — Stalactites and Stalagmites . . 214 xvi CONTENTS

Chapter XII Page

Silicon in the Earth's Crust — Silica — Sand and Sandstone — Quartz — Flint — Opals — Rock Crystal — Discovery of Rock Crystal Caves in the Galenstock — Silica Glass and its wonderful Properties — Quartz Fibres — Solubility of Silica in Water — Geysers and their Siliceous Deposits — Silica Terraces in Volcanic Regions — Silicic Acid — Secretion of Silica by certain Organisms — Constitution of the Earth's Crust — Silicates — Wonderful Structure of Rocks — Weathering of Rocks — Chemical Changes that the Earth's Surface is Undergoing — How Clay and Sand are formed — Glass — Antiquity of Glass Manufacture — Pottery . 265

Chapter XIII

How Sulphur is formed in the Earth — Uses of Sulphur — Wonderful Sulphur Mines of Sicily — A Sulphur Mine on Fire — -Sulphur in Japan — Mountains of Sulphur in the Island of Etrofu — Formation of Sulphur in Craters of Volcanoes — Sulphur Deposits in Java — Wonderful Sulphur Caves — How Montano obtained Sulphur for Cortes from the Crater of Popocatapetl — Probable Existence of Sulphur Deposits on the Moon — Description of the Sulphur Deposits in the Crater of Vesuvius — Sulphur Bacteria — Sulphur in Living Matter — Sulphides — Properties of Sulphur — Sulphuretted Hydrogen and its Dangers — Accidents to Workmen through Sulphuretted Hydrogen in Drains — Evolution of Hydrogen Sulphide from the Ground during the Building of Smith's Point Lighthouse — Sulphur Dioxide — How Pliny Died from Poisonous Gases containing Sulphur Dioxide — Sulphuric Acid 291

Chapter XIV

Discovery of Phosphorus by Brandt — Wonderful Properties of Phosphorus — Manufacture of Phosphorus in the Electric Furnace — Use of Phosphorus for Matches — Dangers of Phosphorus — Phossy Jaw — Poisoning by

CONTENTS xvii

PAGE

Phosphorus — Red Phosphorus — Safety Matches — How Matches are Made — Phosphorus in Living Matter — Phosphorus Manures — Phosphates — The Tale of a Phosphorus Atom 308

Chapter XV

Nature of Fire — Combustion — Structure of Flame — The Bunsen Flame — The Incandescent Mantle — Neglect of Research — Wonders in a Candle Flame— Chemical Analysis of distant Suns — Principles of Spectrum Analysis— Wonders of Spectrum Analysis . " . . 324

LIST OF ILLUSTRATIONS

LINE DRAWINGS IN THE TEXT

Experiment illustrating the Indestructibility of Matter

Use of the Ultra Microscope ....

Shape of the Carbon Atom according to Modern Electron

Theory

Shape of Carbon Atom according to Wislicenus . Dissolved Crystals and their Plane of Polarisation Arrangement of Atoms in Molecule Predominance of Iron in the Earth

The Solar System

Sulphuric Acid Molecule .....

Reaction between PC1 6 and H 2 S0 4 — The Approach Reaction between PC1 5 and H 2 S0 4 — The Collision Reaction between PC1 5 and H 2 S0 4 — Formation of the cules POOL and S0 2 2 , as the result of

Molethe collision .......

Section of the Earth's Crust ....

If Water became Incompressible ....

Temperature of the Sea

Snow Crystals .

Production of Superheated Steam

Preparation of Hydrogen

Hydrogen Flames on the Sun's Surface

Explosion of a Flask filled with Hydrogen and Oxygen

Structure of Hydrogen Gas .....

Structure of Hydrogen Atom ....

Section through the Earth's Atmosphere

Linde's Apparatus for Liquefying Air

Vacuum Jacketed Vessel for holding Liquid Air .

Crystals of Oxyhemoglobin

How the Severn Tunnel was Saved

Preparation of Oxygen Gas from Potassium Chlorate

Linde's Apparatus for separating Air into Oxygen

Nitrogen

Diagram Birkeland-Eyde Electric Furnace .

Some Historic Diamonds

The Benzene Ring and

PAGE

3 23

26 27 23

75 76

181 201 220 233 xix.

xx LIST OF ILLUSTRATIONS

PAGB

Framework of Carbon Atoms in Camphor .... 232

Framework of Carbon Atoms in Indigo .... 232

Framework of Carbon Atoms in Organic Dye . . . 232

Dog Grotto near Naples 238

The Bottomless Pit 257

Echo River, Mammoth Cave . . . . . .258

Exploration of Maelstrom in Mammoth Cave . . . 260

Spear Head 270

Spear Head *" 270

Spear Head, Front and Profile 271

Discovery of Rock Crystal Cave 274

Euplectella Suberea Sponge 280

Microscopic Structure of Siliceous Rocks .... 283

Unburnt Gas in interior of Candle Flame . . . 325

Cool Core in interior of Gas Flame 326

Section of a Candle Flame 328

Bunsen Burner 329

Spectroscope 336

Section of the Sun 338

HALF-TONE PLATES, Etc.

Silica Terraces at Rotomahana Frontispiece

FACE PAGB

Tripler's Apparatus for Experimenting with Liquid Air . 142

Pouring Liquid Air . .146

Kettle of Liquid Air on a Cake of Ice . . . .146

Oxygen-breathing Apparatus 176

Dr. Leonard Hill administering Oxygen . . . .178

Nodule of a Bean Cut Open 196

Nitrogen Assimilating Organisms in a Bean Nodule . . 196

Vigorous Growth caused by Nitrogen Assimilating Organisms 196

Nitrate Works at Notodden 198

Lightning 198

Birkland-Eyde Electric Furnaces 200

Diamond Mines, Open Workings 212

Searching Tables, Diamond Mines 216

A Carboniferous Forest 226

Stalactites 262

Girgenti 294

Sulphur Mountains, Japan 294

In the Crater of Popocatapetl 298

Lunar Landscape 300

Vesuvius 306

Gannets 316

Plesiosaurus and Ichthyosaurus 318

Nebula 338

Spectra 338

TRIUMPHS AND WONDERS OF MODERN CHEMISTRY

Chapter I

The endless circulation of matter in the universe is, perhaps, one of the most wonderful facts with which chemistry has to deal. It is this endless change which causes the history of the most common and insignificant objects about us to be more astonishing than any fairy tale. What a wonderful story, for example, could be written of the material which forms our bodies ! It came into existence in the immense depths of space millions upon millions of years ago, and wandered for ages through darkness and void until it reached our earth. Perhaps it fell upon the earth in a fiery meteorite, or perhaps it merely joined the huge fire mist from which our solid world condensed. Since then it has run round age after age in an endless circle of change. First it formed part of that vast primeval atmosphere which surrounded the globe, and blew in mighty winds around our planet ; then it was absorbed into the body of some humble living being, and when this being died and its body decayed, the matter passed into the rich mother earth. Thence it passed into some plant by means of its roots ; and from the plant it passed, by the process of being devoured, into the body of some animal ; and from the animal again it passed to earth and thence to plants and animals again ; and so on through an endless cycle of change, coursing through the bodies of innumerable multitudes of living forms, which stretch far back in a dim unending vista into the depths of time. Finally it reached man ; yes, the very atoms which thrill and flash in our brains and muscles once formed part of a living plant or animal millions of years ago, and will again form part of a living plant or animal millions of years hence. In some form or other the matter which now forms our bodies will exist long after the whole present order of creation has passed away ; indeed, it may well yet blow in the winds of worlds as yet unborn, and thrill in forms of life not yet evolved.

This ceaseless round of matter seems to have impressed Shakespeare, who has caused Hamlet, not pleasantly, to refer to the subject more than once. In Act IV. Scene 3, we have the man eating the fish that has fed on a worm, which in its turn was sustained upon a dead emperor, and are shown " how a king may go a progress through the guts of a beggar." In Act V. Scene 1, there is the notable speech of Hamlet, when he says,

" Alexander died, Alexander was buried, Alexander returneth into dust : the dust is earth. ; of earth we make loam : and why of that loam, whereto he was converted, might they not stop a beer-barrel ?

Imperious Caesar, dead and turned to clay, Might stop a hole to keep the wind away. O, that that earth, which kept the world in awe, Should patch a wall to expel the winter's flaw ! "

! Not only the material forming our bodies, but every piece of material around us possesses an antiquity so vast as to be almost incredible. What endless convolutions and vicissitudes, for example, has a common lump of earth passed through before it reached its present form ? It has been part of continents which have long since vanished, and has borne the tread of races long since extinct. It has been on the top of mountains and at the bottom of oceans ; it has often formed part of the molten fire underground, and, in spite of all this, it still remains, and will remain during endless ages yet to come.

All these wonders arise from the fact, brought to light by the patient labours of generations of scientific men, that matter is indestructible, that it can be neither generated nor destroyed by any means in our power. It may pass into a totally different series of forms, but at the end of a whole series of changes the same weight of matter remains as was there in the beginning. For example, when a candle burns away it disappears, and the matter forming it is apparently annihilated ; yet this is not really so, for the candle merely burned to invisible gaseous forms of matter, which, when collected and weighed, are found to contain the same weight of carbon and hydrogen (the kinds of matter which make up the candle) as was originally in the candle itself. This latter fact, indeed, can be shown easily by means of a very simple experiment.

A candle C is fixed in a stoppered bottle A (Fig. i) , which is then weighed.

The candle is now lighted by making a platinum wire BB, which encircles the wick, white hot by means of an electric current. The candle burns for a short time, and then goes out.

On reweighing the bottle when it is cold, no alteration in weight will be found to have occurred, although part of the candle has burned into invisible gas.

'•" In the light of recent discoveries, however, it may be doubted whether matter is absolutely indestructible, but there is no doubt that ordinary matter, if decomposable at all, decomposes so slowly that a single pound of it will endure through millions of millions of centuries, a time longer than that required for the whole solar system to evolve.* It is indeed hard to conceive that anyone in full possession * Sir Oliver Lodge, " Modern Views of Matter " (1903), p. 25.

Fig. 1.

of his senses can look into the heavens on a dark starry night and remain unmoved. The fact that he looks into a vast void extending upwards for ever and ever, strewn with innumerable myriads of suns and world-systems must fill even the most brutalised mind with a feeling of awe and bewilderment. Yet the interspace between world and world is not truly empty in the popular sense for it is fiUed with a wonderful medium, termed the ETHER, which fills all the depths of space, and bears through it to us, m the form of minute ripples or quiverings, the light of the distant stars Matter moves through this vast sea of ether apparently without resistance, much as a sieve moves through water or a wind rushes through the trees ; but what "matter" is we do not know. AU that we do know is that it is totally unlike anything which our crude senses conceive it to be, and is probably far more wonderful than anything we can even imagine.