Britain's heritage of science

GIFT OF

BRITAIN'S HERITAGE OF SCIENCE

Sir Isaac Newton

From an engraving of a
painting by Kneller, in the
Possession of Lord Portsmouth

BRITAIN'S HERITAGE
OF SCIENCE

BY

ARTHUR SCHUSTER, F.R.S.

AND

ARTHUR E. SHIPLEY, F.R.S.
ILLUSTRATED

LONDON

CONSTABLE & CO. LTD.
1917

«..*:•

•' - : ' v

m

ERRATA.

Page 70, line 5 from bottom :

far "Robert" read "Charles."

Page 286, line 10 from bottom :

for "Sir William Herschel " read "Sir William
James Herschel, eldest son of Sir John
Herschel."

for " Foulds " read " Faulds."

Page 291 , line 11 from top :

for " Thompson " read " Thomson."

LIST OF PORTRAITS

SIR ISAAC NEWTON - Frontispiece

From an engraving of a painting by Kneller, in the posses-
sion of Lord Portsmouth.

JOHN DALTON - Facing p. 16

From a painting by R. R. Faulkner, in the possession of the
Royal Society.

MICHAEL FARADAY - Facing p. 32

From a painting by A. Blakeley, in the possession of the
Royal Society.

THE HON. ROBERT BOYLE - - Facing p. 72

From a painting by F. Kerseboom, in the possession of the
Royal Society.

JOHN CLERK MAXWELL - Facing p. 86

From an engraving in " Nature " by G. J. Stodart of a photo-
graph by Fergus, of Glasgow.

SIR HUMPHRY DAVY - - Facing p. 112

From a painting by Sir Thomas Lawrence, in the possession
of the Royal Society.

SIR GEORGE GABRIEL STOKES - - Facing p. 124

From a photograph by Fradelle & Young.

370907

vi List of Portraits

JAMES PEESCOTT JOULE - Facing p. 160

From a photograph by Lady Roscoe.

WILLIAM THOMSON, LORD KELVIN - Facing p. 190

From a photograph by Messrs. Dickinsons.

THOMAS YOUNG - - Facing p. 212

From a portrait by Sir Thomas Lawrence.

JOHN RAY - - Facing p. 232

After a portrait in the British Museum.

STEPHEN HALES - - Facing p. 236

After a portrait by Thomas Hudson.

CHARLES DARWIN - Facing p. 268

After a photograph by Messrs. Maidl & Fox.

WILLIAM HARVEY - Facing p. 294

After a painting by Cornelius Janssen, now at the College of
Physicians.

CHARLES LYELL - - Facing p. 310

After a daguerreotype by J. E. Mayal.

SYNOPSIS OF CONTENTS

CHAPTER PAGES

I. THE TEN LANDMARKS OF PHYSICAL SCIENCE 1-45

Roger Bacon — Gilbert, the founder of terrestrial mag-
netism, his electrical researches — Napier's discovery of
logarithms — Continuity of scientific progress in Great
Britain from the seventeenth century onwards — New-
ton's laws of motion and discovery of gravitation —
Importance of Newton's work — Foundation of modern
chemistry by Dalton — Foundation of undulatory theory
of light by Young — Faraday's electrical discoveries —
Conservation of energy established by Joule and Thom-
son— Clerk Maxwell's electro -magnetic theory of light
— His work on kinetic theory of gases — Biographical
notes on Newton, Dalton, Young, Faraday, Joule,
Thomson, and Clerk Maxwell.

II. PHYSICAL SCIENCE — THE HERITAGE OF THE
UNIVERSITIES DURING THE SEVENTEENTH AND
EIGHTEENTH CENTURIES - - 46-71

Activity in the Universities during the seventeenth cen-
tury— Foundation and early history of Gresham College
— Briggs, tables of logarithms and decimal fractions —
Edward Wright and Mercator's projection — Wallis —
• Lord Brouncker's use of infinite series — Wren's mathe-
matical and astronomical work — The Gregory family,
first suggestion of reflecting telescopes — Newton's op-
tical discoveries — Robert Hooke, " Micrographia " —
Flamsteed, first Astronomer Royal — Halley's mag-
netical and astronomical work — Bradley's discovery of
aberration and nutation — Bliss — Maskelyne, founder
of the "Nautical Almanac" — Density of earth — The
Scottish Universities — William Cullen, founder of the
Scottish school of Chemistry — Black's chemical dis-
coveries— Latent heat — Use of hydrogen for filling
balloons — Rutherford's isolation of nitrogen — Robison
— Playfair — Desaguliers — Robert Smith.

viii Contents

CHAPTER PAGES

III. PHYSICAL SCIENCE — THE NON-ACADEMIC HERIT-
AGE DURING THE SEVENTEENTH AND EIGHTEENTH

CENTURIES - 72-105

Distinction between amateurs and professional men
of science — Robert Boyle's life and work — Boyle's law
— Optical and chemical experiments — Taylor's theorem
— Early history of the Royal Society — First record
of electric spark by Hauksbee — Isolation of argon
forestalled — Joseph Priestley, chemical production
of oxygen — Composition of water — Direct proof of
gravitational attraction by Cavendish — Michell's tor-
sion balance — Horrocks, first observation of transit
of Venus — Molyneux — William Herschel, discovery
of Uranus and other astronomical work — Discovery of
infra-red radiations — Importance of construction of
scientific instruments — Oughtred's slide-rule — Gas-
coigne's eyepiece -micrometer — Hadley's sextant — Tem-
perature compensation of pendulum by Graham and
Harrison — Divided circles — Ramsden's eyepiece —
Achromatism : More Hall and Dollond — Early history
of steam engine : Somerset, Savery, Papin, Newcomen
— Improvements by James Watt— Invention of con-
denser— First locomotive constructed by Trevithick —
First compound engine by Hornblower — Murdock and
illuminating gas — Bramah's hydraulic press.

IV. PHYSICAL SCIENCE — THE HERITAGE OF THE

NINETEENTH CENTURY - - 106-142

Nicholson's electrolytic decomposition of water — Cor-
relation of physical forces — Count Rumford's generation
of heat by mechanical power — Humphry Davy — Dis-
covery of laughing gas — Isolation of metallic potassium
and sodium — Safety lamp — Revival of scientific re-
search at Cambridge — Woodhouse, Peacock, Whewell —
Physical optics advanced by Airy and Baden Powell —
The golden age of mathematical physics at Cambridge
— Green — Stokes' researches on light and hydrodynamics
— Fluorescence — Discovery of Neptune by Adams —
Sylvester, Cayley, Routh — Miller's work on crystallo-
graphy— Physical science in the Scottish Universities —
Maximum density of water discovered by Hope —
Leslie's investigations on radiant heat — Brewster's
researches on light — Important work of Forbes — Tait,
Chrystal, Kelland — Rankine and conservation of energy
— James Thomson — Hamilton, discovery of conical
refraction — Physical science in Ireland — Trinity College

Contents ix

CHAPTER PAGES

— Lloyd, McCullagh, Jellett, Salmon, Haughton — Fitz-
gerald, Johnstone Stoney — Andrews on ozone and
liquefaction of gases — Science at Oxford : Henry Smith,
Odling, Vernon Harcourt, Pritchard.

V, PHYSICAL SCIENCE — THE HERITAGE OF THE

NINETEENTH CENTURY — (continued)- - 143-186

Foundation of University of London — University Col
lege and King's College — De Morgan — Graham's re-
searches on gases — Discovery of palladium and rhodium
by Wollaston — Chemical work of Williamson — Electrical
researches of Wheatstone — Owens College and Man-
chester University — Chemical school of Frankland and
Roscoe — Osborne Reynolds and scientific engineering —
Balfour Stewart on radiation and absorption — History
of spectrum analysis — Discovery of thallium by Crookes
— Riicker's researches on thin films, his magnetic sur-
veys— Poynting and energy paths — Radiation pressure
— Distinguished work of amateurs : Baily, Gassiot,
Grove, Spottiswoode, Schunck, Sorby — Waterston's
neglected investigations on theory of gases — Progress in
astronomy : John Herschel, Gill, Rosse, Lassell, Nas-
myth — Application of photography to astronomy : de
la Rue, Common, Roberts — Application of spectrum
analysis to astronomy : Lockyer, Huggins — Newall's
large telescope — Early history of photography : Wol-
laston, Wedgwood, Herschel, Fox Talbot — Dry plates
and gelatine emulsions — Abney's work on theory of
photography — Colour photography : Rayleigh, Joly —
Geophysical work of Kater, Sabine, Clarke — Meteoro-
logical work of Wells, Howard, Apjohn, Glaisher,
Archibald, Buchan, Aitken — George Darwin and cos-
mical evolution — Foundation of seismology by Milne —
Recent advances in physics — Rayleigh's discovery of
argon — Researches of Ramsay — Discovery of helium —
Crookes' radiometer — His improvement of air pumps —
J. J. Thomson and electric discharge through gases —
Electric constitution of matter — Larmor — Discovery of
radio-activity — Rutherford's discovery of emanation —
Theory of radio-activity — Moseley's brilliant researches
and early death.

VI. PHYSICAL SCIENCE — SOME INDUSTRIAL APPLI-
CATIONS - - - - 187-202

Manufacture of steel — The electric telegraph : Ronalds,
Cooke, Wheatstone — Submarine cables : Kelvin, Newall,
Hancock — Vulcanization of rubber — The microphone

x Contents

CHAPTER PAGES

of Hughes — Sturgeon's electromagnet — Development of
electrical industry — Wilde — Hopkinson, Ewing, Ayrton
The alkali industry : Gamble, Leblanc, Muspratt, —
Gossage, Solvay, Mond, Deacon, Weldon — Royal Col-
lege of Chemistry — Discovery of coal-tar dyes — Perkin,
Nicholson — Early promise and subsequent neglect of
industry — Meldola — Explosives : Abel, Dewar — Play-
fair and encouragement of science.

VII. PHYSICAL SCIENCE — SCIENTIFIC INSTITUTIONS 203-215

Early history of Royal Society — Privileges as regards
patents — Their action in promoting food production,
inoculation, the prevention of jail fever, and protection
against lightning — Repository of natural rarities — Pro-
motion of scientific expeditions, surveys — Comparison
of standards — Connexion with Greenwich Observatory
and Meteorological Office — Foundation of National
Physical Laboratory — Friendly relations with foreign
academies — Royal Society of Dublin — Royal Society
of Edinburgh — Royal Society of Arts and other scientific
societies — Constitution of Royal Society compared with
that of foreign academies — Royal Institution — Dewar's
work on liquefaction of gases — The British Association.

VIII. BIOLOGICAL SCIENCE IN THE MIDDLE AGES- 216-228

Physiologus — Bartholomew's " Liber de Proprietatibus
Rerum " — Roger Bacon — yesalius, the founder of
modern anatomy and physiology — Moffett — Biological
science in Elizabethan and Stewart times — Francis
Bacon — Lord Herbert — Evelyn — Pepys — King Charles'
interest in science.

IX. BOTANY - - 229-255

Early herbalists — Turner, Gerard, Johnson — New era
inaugurated by Ray — Morison — Grew, one of the
first students of vegetable anatomy — Hales, the
founder of the physiology of plants — Knight and cir-
culation of sap — Foundation of Linnsean Society by
Smith — Scientific explorers : Sloane, Banks — Great
Britain leads the way in introducing scientific classifica-
tion— Robert Brown — Discovery of nucleus of cells —
Brownian movement — Lindley, a great taxonomist —
The elder Hooker, Bentham — -Joseph Hooker; early
expeditions, friendship with Darwin, Himalayan
travels — Flora Indica — Huxley's influence on teaching
of botany — Berkeley and cryptogamic botany — Botany

Contents xi

CHAPTER PAGES

at Oxford : Sherard, Sibthorp, Daubeny — Botany at
Cambridge : Martyn, Henslow, Marshall Ward — Botany
in Scotland : Sutherland, Greville, Balfour — Botany in
Ireland : Threlkeld, Allman — Historical summary of
British Botany.

X. ZOOLOGY - - 256-293

Early history — Turner, Wotton, Caius, Topsell —
Influence of falconry — Willughby and Ray — The Tra-
descants — Zoology in eighteenth century : Pennant,
William Hunter— -John Hunter, his zoological collections
— Revival in nineteenth century — Owen — His efforts
to reorganize the natural history department of British
Museum — Charles Darwin — His ancestry, Erasmus Dar-
win— Studies at Edinburgh and Cambridge — Voyage
of the "Beagle" — Appreciation of Darwin's work by
Wallace — History of evolution and natural selection —
Heredity — Early supporters of Darwin : Huxley, Lyell,
Hooker — The work of Wallace — Allman — Huxley,
morphologist, teacher, and organizer — F. M. Balfour's
work on embryology and early death — Romanes, Sedg-
wick — Biometrics : Weldon, Galton — Ray Lankester,
his work on morphology and other branches of zoology
— Maritime zoology — Edward Forbes, Gosse — Voyage
of " Challenger " — Scientific results of cable laying —
Progress in scientific classification during nineteenth
century — Exploration of Central America by Godman
and Salvin — Marine stations and laboratories.

XI. PHYSIOLOGY - 294-307

Harvey, the circulation of blood — Mayow's researches
on respiration and the oxidizing of venous blood,
muscular heat — Medical science and physiology — Syden-
ham, Glisson, Lower and the transfusion of blood —
Willis and brain anatomy — Havers' " Osteologia Nova "
— Important researches of Hales, blood pressure, secre-
tions— Joseph Black's contributions to physiology —
Hewson, discovery of lymphatic and lacteal vessels —
Coagulation — Young, founder of physiological optics
— Addison — Bowman — Cambridge School of Physio-
logy— Michael Foster — Gaskell, studies on nerves and
heart action — Action of chloroform on heart — Sharpey
— Specialization of biological science— Wooldridge —
Contributions to the practice of medicine — Discovery
of chloroform by Simpson — Jenner, preventive inocu-
lation— Bell — Lister's antiseptic surgery — Roy.

xii Contents

CHAPTER PAGES

XII. GEOLOGY - 308-319

Great Britain, a geological microcosm — William Smith,
rock strata — Beds of rocks characterized by fossils —
Chronological sequence — Hutton and the Huttonian
theory — Lyell and Uniformitarianism — Allport, D.
Forbes — Sorby, crystal structure — Influence of local
surroundings — The district of St. David's, oldest rocks
in Great Britain — Aymestry limestone — The Silurian
system — Sedgwick, Cambrian rocks — Miller, old red
sandstone — Delabeche, importance of mapping — The
Government geological survey — Phillips — New red sand-
stone— Fitton and Mantell — Prestwich, E. Forbes —
Palseontological work by Davidson and others — James
Geikie — Archibald Geikie — Buckland, diluvial deposits
— Economic geology.

INDEX 321

PREFACE

HPHIS book does not pretend to establish any thesis.
•*• Incidentally it may point a moral which different
readers will interpret in different ways. Our main
purpose was to give a plain account of Britain's great
heritage of science; an heritage that — handed down
through several centuries of distinguished achieve-
ments— will, if the signs speak true, be passed on to
the coming age with untarnished brilliancy.

A limit had to be set to the extent to which
contemporary science should be included, and some
difficulty was felt in fixing that limit. It seemed
desirable — for obvious reasons — to avoid discussing the
work of living men ; but no fixed rule could be enforced
because that work is often too much interwoven with
that of others who are no longer with us to be com-
pletely ignored. Sometimes, also, researches undertaken
by our present leaders have led to results that are
firmly established, and to have omitted them would
have conveyed a false idea of the part which Great
Britain has played in the recent progress of science.
In such cases we had to use our discretion in breaking
through a rule which — as a principle — we have tried to
adhere to.

xiv Preface

It was not intended to write a complete history of
British science, but to lay stress mainly on its salient
features, without overburdening our account with work
which, though meritorious and perhaps precursory to a
real advance, did not deal with fundamental matters.
Our judgment probably was at fault in some cases, and
accidental omissions have, no doubt, also occurred. It
is to be expected that these will be most numerous in
the chapter on technical applications, where it was
found difficult to select from the extensive material
those special instances which most clearly show the
part that pure science has taken in the economic life
of the country.

The subject naturally divides itself into two great
groups, one dealing with the physical, the other with
the biological sciences, and we are respectively respon-
sible for the one and the other. Our thanks are due
to Professor Seward, Master of Downing College, Cam-
bridge, for kindly helping in the chapter on Botany ;
to Mr. H. H. Brindley, of St. John's College, Cambridge,
for his assistance in the chapter on Zoology ; and to
Professor F. G. Hopkins for help in that on Physiology.
The chapter on Geology was partly re-written and much
increased in value by the late Professor McKenny
Hughes, while Dr. Marr and Mr. R. E. Priestley have
also assisted us with advice. Extensive use has been
made of the " Dictionary of National Biography," and
of some articles in the " Encyclopaedia Britannica."

Preface xv

Part of the History of Biological Science has been
taken, by kind permission of the Editors and of the
authorities of the Cambridge University Press, from
the "Cambridge History of English Literature." In
that portion of the chapter on Zoology which deals
with Charles Darwin considerable extracts have also
been made from the Presidential Address to the Zoo-
logical Section of the Winnipeg Meeting of the British
Association.

Our thanks are due to the Council of the Royal
Society for permission to reproduce a number of por-
traits, and to the Editor of " Nature " for allowing
the reproduction of the excellent engraving of Clerk
Maxwell. The portraits which accompany the last five
chapters were prepared from photographs kindly taken
by the Rev. Alfred Rose, of Emanuel College, Cam-
bridge, from various well-known prints. The excellent
likeness of Joule, taken about 1875 by Lady Roscoe,
now appears for the first time.

A. S.
A. E. S.
August 1917.

BRITAIN'S HERITAGE OF SCIENCE

CHAPTER I
THE TEN LANDMARKS OF PHYSICAL SCIENCE

(Roger Bacon, Gilbert, Napier, Newton, Dalton, Young,
Faraday, Joule, William Thomson, Clerk Maxwell)

history of British Science begins with Roger Bacon,
JL the Franciscan friar, who, cutting himself adrift
from the scholastic philosophy of his time, rejected the
traditional appeal to recognized authority, and urged with
a powerful voice that a knowledge of Nature can only be
attained through experimental research and by logical
reasoning. Intellectually he stood high above the level of
his contemporaries;1 by his writings he set the true
standard of scientific enquiry, and planted the first of the
great landmarks along the path of British science.

" There are two methods," he writes, " in which
we acquire knowledge, argument and experiment. Argu-
ment allows us to draw conclusions, and may cause us
to admit the conclusion ; but it gives no proof, nor does
it remove doubt, and cause the mind to rest in the
conscious possession of truth, unless the truth is dis-
covered by way of experience, e.g., if any man who had
never seen fire were to prove by satisfactory argument
that fire burns and destroys things, the hearer's mind
would not rest satisfied, nor would he avoid fire; until
by putting his hand or .some combustible thing into
it, he proved, by actual experiment what the argument
laid down; but after the experiment had been made,
his mind receives certainty and rests in the possession
of truth, which could not be given by argument but

1 An interesting account of the general character of scientific
speculations before Bacon's time has been given by Charles L. Barnes
(" Manch. Lit. and Phil. Soc.," Vol X. 1896).

2 Britain's Heritage of Science

only by experience. And this is the case even in mathe-
matics, where there is the strongest demonstration.
For let anyone have the clearest demonstration about an
equilateral triangle without experience of it, his mind will
never lay hold of the problem until he has actually before
him the intersecting circles and the lines drawn from the
point of section to the extremities of a straight line."1
In a more detailed discussion of experimental science,
he points to three " prerogatives " which it has over other
sciences. It tests the conclusions of these other sciences
by experience, it attains to a knowledge of truth which could
not be reached by the special sciences, and " it has no
respect for these, but investigates on its own behalf the
secrets of Nature, which consist in a knowledge of the future,
the past and the present, and the inventing of instruments
and machines of wonderful power."

We further note Bacon's repeated plea for the study of
mathematics, which he judges to be " the key and door to
the special sciences."

Roger Bacon was born about 1214, in the county of
Dorset, of wealthy parents. Having completed his studies
at Oxford, he seems very soon to have gained a reputation
by lecturing, both at Oxford and Paris, where he went
about 1236. He entered the Franciscan Order, and, though
in bad health, continued his studies, devoting part of his
time to optical experiments.

" During the twenty years," he writes in 1267, " in

which I have laboured specially in the study of wisdom,

after abandoning the usual methods, I have spent more

than £2,000 on secret books and various experiments and

languages and instruments and mathematical tables, etc."

Bacon found a friend in Pope Clement IV. , an enlightened

Frenchman, who,.having been a lawyer and judge, took orders

after his wife's death and rapidly rose in the Church. In

1263 Clement was appointed papal legate in England, and

it was probably then tlaat he came to hear of Bacon's

writings. When elected Pope, two years .later, he asked

1 The translation (with a slight modification) is that given by
Prof. R. Adamson (see " Cbjnjnejnoration JCssays on Roger Bacon,"
edited by A. G. Settle, p. 18).

Roger Bacon 3

for fair copies of Bacon's works, who, thinking that nothing
he had yet written was good enough, set out on a more
ambitious undertaking, of which the " Opus Majus " was the
first instalment. In this work he displayed such indepen-
dence of thought, and attacked the prevailing ideas so
forcibly, that his opponents were converted into bitter
enemies. They saw their opportunity — and used it — when
Clement died. Accusations of heresy were raised, and
Roger Bacon was condemned to prison by the General of the
Franciscan Order in 1277. He remained in captivity till
shortly before his death, which took place in 1292.

With Roger Bacon England took the lead in laying the
foundation of modern science. While the scholastic tradi-
tion held the whole of Europe in bond he stood alone,
fearlessly holding up the torch of enlightenment; but its
rays fell on eyes that could or would not see. More than
three barren centuries separated Bacon from the next great
scientific figures, William Gilbert and John Napier.

Gilbert (1540-1603) has been called the father of electric
and magnetic science. He belonged to an old Suffolk family,
was born at Colchester, and after a distinguished career
at Cambridge, spent three years in Italy and other parts
of Europe. On his return he settled down in London as a
medical practitioner, and soon gained a reputation which
secured him many honours, and among them the appoint-
ment as physician to Queen Elizabeth. His chief work is
described in a volume published in 1600 under the title of
" De magnete, magnetisque corporibus et de magno magnete
tellure."

It was known to the Greek philosophers that a, certain
mineral originally found in Magnesia had tin pow^r of
attracting small pieces of iron. In the twelfth .century the
knowledge of the compass was brought to JSurope. jChe
Chinese, who had been familiar with it jn very early times,
already knew that the clireotion in which the needle points
was a little to one side of North, and Columbus discovered
that this deviation differed in different localities. Nearly
a century later, Robert Norman, a British sailor, had
observed that the .force which acted on the needle was not,
*s bad generally beeto assumed, directed upVards towards

A 2

4 Britain's Heritage of Science

the pole star, but downwards, and in 1576 he measured
the angle between the horizontal and the direction of the
magnetic needle, which we now call the magnetic dip, and
found it to be nearly 72° in London. Such was the know-
ledge at Gilbert's disposal when he began his celebrated
researches. The word " loadstone " for the magnetic mineral,
derived from lead-stone, indicates how the main interest in
magnetic properties had been concentrated in their use for
purposes of navigation. Gilbert's object, on the other
hand, was chiefly scientific. The high position which he
occupies in the history of science is not merely due to his
discoveries, but to a great extent on his being the first man
of science who gave effect to Roger Bacon's teaching,
possessing the power and will to draw logical conclusions
from his experiments, and to verify by new experiments
the wider views suggested by these conclusions.

Mapping out the directions in which a freely suspended
magnetic needle sets at different points on the earth's
surface, it appears to us a simple matter to infer that the
earth as a whole behaves like a huge magnet. A diagram
seems to be all that is required to complete the deduction.
But the world at the time was not accustomed to logical
reasoning of this kind. It was necessary, therefore, to
enforce conviction by corroborative evidence, which Gilbert
supplied, showing that the earth, so far as could be tested,
possessed all the properties of a magnet. He pointed out
that rods of iron lying about become magnetic under its
influence, just as when placed near magnetized iron, and
he noted that the effect is the stronger the more nearly
the direction of the rods coincides with the direction in
which a suspended needle comes to rest. Gilbert further
•constructed a" magnetic sphere, and suspending small
.magnets by thin fibres, he examined how these set in
different directions at different points on the sphere. He
could thus, on a small scale, reproduce a model of the
earth as a magnet, and. observing that the magnetic forces
extend beyond the surface of his " terellum," was led to
speculate on the possible action of terrestrial magnetism on
the moon, and the mutual magnetic effects of planets on
each other. We readily forgive him if in these cosmic

William Gilbert 5

speculations he travelled beyond the justifiable limits of his
experimental facts.

In his electrical researches Gilbert had the same wide
outlook. Amber, when excited by friction, was known to
attract light bodies; why — he asked himself — should special
properties be confined in one case to iron and in another to
amber? He tried but failed to find a magnetic action on
water and other bodies, but discovered that the property
of amber was shared by a large number of substances,
such as glass, sulphur, and the precious stones. He was
the first to note that electric effects persist longer in dry
air than in wet weather, that an electrified body loses its
power when moistened with water or spirit, or when glowing
coal is brought near to it. We also owe to him the word
" electricity " (derived from " rj\«Tpov ", the Greek word for
amber) ; though only in the form of the adjective. " Vim
illam," he writes, " electricam nobis placet appellare,
quse ab humore provenit." In a posthumous work he
declares himself to be an adherent of the Copernican
doctrine, and shows a clear scientific perception, as when
he explains that there is no intrinsic property of " levity,"
but that when light bodies are seen to ascend they do so
under the influence of the pressure of the surrounding
heavier bodies.

Galileo,1 almost the only man of science born in the
sixteenth century who stands on an intellectual level with
Gilbert, appreciated his work. In the third of the famous
" Dialogues " he gives an account of it, and Salviati, the
imaginary person who is made to express Galileo's own
views, mentions Gilbert's book, " which might not have
come into my hands if a peripatetic philosopher had not
presented it to me, for the reason, I believe, that he did
not wish to contaminate his own library with it." After
referring to some of Gilbert's experiments, Salviati further
says :

" I highly praise, admire, and envy this author for

having formed such a stupendous conception on a

1 The name is given in its usual form, but it sounds rather like
calling a man Thomas whose full name is Thomas Thomasson. Galileo's
father was Vincenzio Galilei ; his own full name Galileo Galilei.

6 Britain's Heritage of Science

matter which has been treated by many sublime
intellects, but solved by none; he appears to me also
to deserve the highest praise for his many and true
observations, putting to shame the lying and vain
authors who write not only of what they know, but
also of what they hear from the silly crowd, without
satisfying themselves by experiment of what is true —
perhaps, because they do not wish to shorten their
books. What I should have desired in Gilbert is that
he would have been a little more of a mathematician,
and especially well schooled in geometry, the practice
of which would have made him less inclined to accept,
as conclusive proofs, what are only arguments in favour
of the deductions he draws from his observations. . .
. . . I do not doubt that in the course of time this
new science will be perfected by new observations, and
by true and cogent demonstrations. But the glory
of the first inventor will not be diminished thereby;
I do not esteem less, but, on the contrary, admire, the
first inventor of the lyre (though probably his instru-
ment was roughly constructed and more roughly played),
much more than the hundred other players who, in the
succeeding centuries, have brought his art to exquisite
perfection."

Coming from Galileo this was high praise, indeed.
The next landmark was planted by a man of equal
power but different type of intellect.

John Napier, of Merchiston, descended from a distin-
guished Scotch family, which, in the fifteenth century,
included three Provosts of Edinburgh among its members.
His father, Sir Archibald Napier, was Justice Deputy under
the Earl of Argyll, and Master of the Mint. John was
born at Merchiston Castle in 1550; after a short period
of study at the University of St. Andrews, he probably
spent some time in foreign travel, but returned to Scotland
at the age of twenty-two. Though involved in the political
and religious controversies of his age, he devoted his spare
time to the study of mathematics, and, what to him seemed
of greater importance, the writing of a book on the Apoca-
lypse. This mathematical work culminated in the discovery

John[Napier 7

of logarithms, and gave to the world a method by means
of which multiplication is converted into addition, division
into subtraction, and the extraction of square or cube root
into a division by two or three respectively. The scientific
merit of introducing logarithmic functions into the domain
of mathematics is surpassed by the incalculable importance
of assisting the complicated numerical calculations which
were vital to the progress of astronomy and of other branches
of science. Without explaining the objects which Napier
primarily had in view, or the steps by which he arrived at
his final results, we may justify the prominent position
here given to him in the history of science by quoting a
few passages from an article contributed by Dr. J. W. L.
Glaisher to the " Napier Tercentenary Memorial Volume " :
" The process of multiplication is so fundamental
and direct that, from an arithmetical point of view,
it might well be thought to be incapable of simplifica-
tion or transformation into an easier process, so that
there would seem to be no hope of help except from
an apparatus. But Napier, not contented with such
aids, discovered by a most remarkable and memorable
effort of genius that such a transformation of multipli-
cation was possible, and he not only showed how the
necessary table could be calculated, but he actually
constructed it himself. That Napier at a time when
algebra scarcely existed should have done this is most
wonderful; he gave us the principle, the method of
calculation, and the finished table.

" The * Canon Mirificus ' is the first British contribution
to the mathematical sciences, and next to Newton's ' Prin-
cipia ' it is the most important work in the history of the
exact sciences that has been published in Great Britain,
at all even' s until within the memory of living persons.

" In whatever country the ' Canon Mirificus ' had
been produced, it would have occupied the same com-
manding position, for it announced one of the greatest
scientific discoveries ever made."

Independently of his work on logarithms, Napier's con-
tributions to spherical trigonometry would alone have
secured him a high position among mathematicians.

8 Britain's Heritage of Science

The interval between the death of Gilbert in 1603 and
that of Napier in 1617 marks the period of Galileo's astro-
nomical discoveries and of Kepler's fundamental work on
planetary orbits. The world was now waiting for a great
generalization, but Kepler passed away and Galileo died an
old and broken man before one was born who surpassed
both in genius and power as much as they had excelled those
who went before them.

From the seventeenth century onwards, British science
has continuously advanced, sometimes rushing ahead with
torrential energy, sometimes in a smooth and almost imper-
ceptible flow ; at one period chiefly concentrated in the uni-
versities; at others almost entirely kept alive by private
enthusiasts ; but taken as a whole never losing contact with
past achievements or ceasing to foreshadow future conquests.
To appreciate correctly the different stages of the advance,
we must distinguish between the slow work of accumulating
facts or proving and disproving theories and the generation
of new ideas which suddenly alter the whole trend of
scientific thought. Such creations form the seven land-
marks which bring us to nearly the end of the nineteenth
century : Newton's establishment of the law of gravitation,
Dalton's atomic theory, Faraday's electric discoveries,
Young's contribution to the wave-theory of light, Joule's
foundation of the conservation of energy, Kelvin's demon-
stration of the dissipation of energy; finally, Maxwell's
formulation of the electro-magnetic theory of light.

Roger Bacon made an acute remark to the effect that
while in mathematics we can proceed from the simple to
the more complicated, it is impossible to do so in other
branches of science, because Nature does not, as a rule,
present us with the simple phenomenon. The whole history
of science shows how it is always struggling in search of the
simple starting point with respect to which we are constantly
driven to modify or even reverse our ideas. Thales believed
water to be the elementary substance from which everything
else could be derived, Anaximenes thought it was air, and
Heraclitus substituted fire, while, according to Pythagoras,
it was the relations between integer numbers which formed
the foundation of all science.

Sir Isaac Newton 9

Take the case of " rest " and " motion." At first sight
it seems obvious that the former is the simpler phenomenon ;
but our trouble begins when we try to define " rest." Dis-
regarding this difficulty, let us ask ** What is the simplest
kind of motion ? " Every schoolboy now could give the"
answer : "A uniform motion in a straight line " ; but he
would be sorely puzzled if he were required to give an example
of a body moving with uniform motion in a straight line, for
such a thing does not exist. The Greek philosophers kept
more in touch with realities when they considered motion
in a circle to be the simplest of its kind, because they had
observed that the stars describe circles in the sky, and they
could artificially produce circular motion by tying a weight
to a string and whirling it round. As astronomy advanced,
and the motion of the planets were further investigated,
it became more and more difficult to reduce everything to
circular motion. All efforts to persevere in such attempts
finally broke down when the laws regulating the fall of
bodies from a height were discovered. The straight line
motion — although never directly brought within the range of
observation — then took its place as the simpler basic idea.

Sir Isaac Newton (1643-1727) formulated the laws of
motion ; they - have formed ever since the foundation of
physical science, and a few words must be said as to their
significance. Our first idea of " force " is derived from
muscular sensation. We push a body, and see it change its
place, and are conscious that we can ourselves be made to
move by an application of muscular force from outside.
From this it is natural, though perhaps not altogether logical,
to conclude that every change of motion which we observe
in a body is due to some push or pull on that body. This
imaginary push or pull we call a force. The first law,
originally due to Galileo, asserts that absence of force does
not necessarily imply that a body is at rest ; it may be moving,
but, if so, it continues to move in a straight line with unaltered
velocity. The second law allows us to measure a force, and
may be said to have been first applied by Huygens. The
third law asserts that whenever we observe a change of
motion in a body there must be an equal and opposite
change of motion in another body or system of bodies. This

10 Britain's Heritage of Science

is the law of u action and reaction," which has played so
important a part in the history of science.

Having accurately defined what is meant by change of
motion, Newton in his " Principia " establishes a number
of propositions relating to the motion of a body acted on
by a force directed to a fixed centre. The Copernican
hypothesis that the earth and planets are in motion round
the sun, replacing the older view which believed the earth
to be the centre of the universe, was at that time generally
accepted by scientific men, and Kepler had formulated three
laws defining the orbits of the planets. Newton's pro-
positions, applied to Kepler's laws, proved that the movements
of the planets may be accounted for by imagining attracting
forces to act between the sun and the planets diminishing
in proportion to the squares of the distances. If this attrac-
tion be accepted, it is natural to identify it with the force
that keeps the moon in its orbit round the earth, and finally
with that which we observe directly when a body falls down
from a height. But it had to be proved that the intensity
of gravitation at the surface of the earth and that acting
on the moon were related to each other according to the
law deduced from the planetary motions; in other words,
as the distance between the centres of the earth and moon
is 60 times the earth's radius it had to be shown that
the gravitational force at the surface of the earth is 3,600
times as great as that which keeps the moon in its orbit.
The calculation is easily made if we know the length of the
earth's diameter, and this having been ascertained with
sufficient accuracy by Picard in France shortly before the
publication of the " Principia," Newton had the satisfaction
of finding an almost perfect agreement. His theory was
confirmed, and it was definitely proved that the motion of
the planetary system, as well as the behaviour of heavy
bodies on the surface of the earth, could all be deduced from
the general proposition that every particle of matter attracts
every other particle with a force which varies in the inverse
ratio of the square of the distance.

Commentators on Newton's work frequently draw atten-
tion to the delay in publishing for ten years or more the
results of his calculations, because when they were first

Sir Isaac Newton 11

completed there seemed to be a discrepancy of about 11 per
cent, between the value of gravity at the surface of the earth
as deduced from the moon's orbit, and that which can be
observed directly. It has even been said that, for a time,
he rejected the theory altogether, but there is reason for
believing that the delay was due to one uncertain step in the
argument which might have caused an error and accounted
for the disagreement. Newton consequently deferred publi-
cation until he could satisfy himself with regard to this
doubtful point. The attraction of the earth as a whole is
made up of the attraction of its separate parts. When the
attracted body is at a distance, no great error can be committed
by assuming the earth's mass to be concentrated at its centre,
but it might be otherwise, if it is near the surface. Ulti-
mately, Newton proved that, when the law of attraction
is that of the inverse square, we may indeed take the
attraction of a sphere at all distances to be the same as that
of an equal mass placed at its centre. The real cause of the
disagreement was then found to be the inaccurate value
originally adopted for the circumference of the earth. When
the measurements of Picard became known the agreement
was found to be complete.

The importance of Newton's discovery extended far
beyond its immediate results; its wider and far-reaching
effect lay in the demonstration it supplied that by means
of a rigorous mathematical analysis the facts of Nature can
be represented not only in the vague speculative manner
which then was considered sufficient by the majority of
philosophers, but definitely and quantitatively, allowing
a numerical test to be applied. Apart from the philosophic
value of a rigorous treatment, the human mind is always
strongly (on occasions too strongly) impressed by numerical
coincidences. Newton's investigation which enabled him to
calculate the force of gravity at the earth's surface from the
time of revolution of the moon therefore earned conviction,
and was accepted by the majority of his countrymen ; but
it took some time before the continent of Europe gave its
full assent, and the criticisms which were raised illustrate
the danger of taking up too definite an attitude with regard
to the ultimate starting point representing the simple

12 Britain's Heritage of Science

phenomenon from which everything else should be derived.
In France, at any rate, the influence of Descartes' philosophy
was paramount, and Descartes had truly started from the
beginning : " I think, therefore I exist," was to him the
only justifiable & priori assertion to make ; everything else
was to be deduced from that proposition. With a most
powerful and original intellect, he had developed an ingenious
and in many ways logical and consistent system, in which
there was no room for the motion of .any body except that
which was brought about by the impulse of another body
which itself was in motion. If the planets revolve round
the sun, it was to him, therefore, clear that they must be
carried along by an invisible medium whirling round the
sun. Hence his hypothesis of gigantic vortices filling all
space. This is not the place to explain how all phenomena
in Nature were supposed to be accounted for by such means,
but it is clear that the hypothesis was elastic, and could be
varied, added to, and infinitely extended, whenever some
difficulty arose. What concerns us here is that it seemed
to go to the foundation of things — the origin of motion —
and to those trained up in the doctrine of vortices, the mere
postulate of a universal attraction to account for one set
of natural phenomena, disregarding all the rest, seemed to
be a retrograde step. Hence very naturally arose consider-
able opposition, and it was mainly those who disagreed with
Descartes and believed in the possibility of action at a
distance, who inclined towards Newton. But this was
really beside the point, because Newton expressly guards
himself against the implication that his theory necessarily
involved action at a distance, the origin of gravitational
force being in no way prejudged by the affirmation of its
existence. We have here an example of the often re-
curring struggle between a general but indefinite hypothesis
which suggests many things, but cannot be submitted to a
numerical test, and what is characteristic of the Cambridge
school of investigation. This school, which had its period
of triumph in the nineteenth century, clearly defines a
problem, confining it to such limits, wide or narrow, as will
convert it into a precise problem which can be formulated
and submitted to mathematical analysis. There must

Sir Isaac Newton 13

always be a definite answer to a definite question, and,
unless the mathematical difficulties vare insuperable, the
consequences of any assumption may be obtained in a form
in which they can be tested, not only as to their general
nature but also as to their numerical values. The result
may not be far-reaching, but within its limited field it is
definite. We may not have penetrated to the foundation
of the building, but we shall have mapped out one of its
apartments and perhaps reached a fresh starting point.

Two centuries and a quarter have now passed since the
publication of Newton's " Principia," and during that time
our astronomical measurements have become more and
more accurate. Though the mathematical analysis has
sometimes found it difficult to keep pace with the improved
methods of observation, Newton's simple law of the inverse
square has hitherto always been found sufficient to explain
apparent irregularities in the motion of the celestial bodies,
with perhaps the solitary exception of an irregularity in
the motion of Mercury, which may ultimately be cleared up
without calling in some other agency or perhaps is destined
to open out an entirely new aspect of gravitation.

The most precious heritage bequeathed to us by Newton
is this : He has given us the confidence that, complicated
as the problems of Nature may be, they are soluble if we
confine ourselves to a limited and definite range, and follow
up by irrefragable logical or mathematical reasoning the
consequences of clearly-defined premises.

By his laws of motion Newton laid the foundation of
modern dynamics. The next great advance relates to
the constitution of "matter." Common experience shows
that . each .piece of matter may change in shape or volume ;
it even seemingly vanishes, as when water evaporates, or
is freshly formed, as when dew is deposited on. a blade of
grass. If this be kept in mind, we are forced to concede,
in opposition to the school which, professes to. reject all
theories, that an introspective philosophy entirely detached
from observation may lead to a truth hidden from the pure
experimentalist. To perceive that matter in spite of all
appearances is indestructible goes beyond the limits of
our direct observation; and a science without imagination

14 Britain's Heritage of Science

confining itself to that which it can see would have grown
very slowly indeed. We owe that much to the Greek
philosophers, that they took a wider view, and at any rate
tried to evolve a system which would satisfy our sense
of harmony in the perception and interpretation of Nature.
Their imagination frequently led them astray, but as often
prepared the way for the evolution of the correct view. The
idea that all matter is composed of separate small particles
which cannot further be subdivided appears very early
among the Greek philosophers. Anaxagoras, in the fifth
century before Christ, assumed the existence of indestructible
and immutable elements of which all bodies are composed,
and called them " seeds." Half a century later, Democritus
first used the word " atom," but differed from Anaxagoras
by ascribing the different properties of bodies not to a differ-
ence in kind, but merely to one in shape and arrangement.
Aristotle rejected this hypothesis completely, and his
unhappy doctrine, apparently borrowed from Indian sources,
which treats matter as an embodiment of mixtures in different
proportions of the imaginary elements, fire, earth, water,
and air, had a most paralysing influence on the history of
science. The atomic theory consequently remained through
centuries the subject of metaphysical speculations and the
plaything of philosophers; as the foundation of chemical
science, it takes its place only in modern times. But
one great obstacle had to be removed. The chemistry
of the eighteenth century was entirely under the influence
of an erroneous theory of combustion, according to which
inflammable bodies contained an invisible substance —
" phlogiston "^-showing itself as a .flame on being expeUed,
and no progress was possible until the true nature of com-
bustion had been demonstrated by the eminent French
chemist Lavoisier. .His explanations were so simple and
convincing that ifr js difficult to understand why the atti-
tude taken up by JEngJisfr chemists with regard to them
was entirely hostile. Cavendish, like Black and Priestley,
adhered to the phlogiston theory, even when the latter, by
his discovery of oxygen, .had supplied the c.hief weapon by
which it ultimately .fell.

Robert Boyle (1627-1691) had clearly shown how a

John Dalton 15

sharp distinction between elementary and compound bodies
could be drawn, and even explained the difference between
mixtures and chemical compounds. But it was only when
phlogiston had been finally abandoned that the way was
prepared for our present conception of the constitution of
matter. This is indelibly connected with the name of John
Dalton (1766-1844), who taught us that the material uni-
verse contains a certain number of elementary substances,
each possessing, as its ultimate constituent, a distinctive
atom which cannot be split up farther by chemical or
physical means. There are, therefore, as many different
kinds of atoms as there are elementary substances. The
atoms of each element are alike in every respect, and have
the same weight. When atoms of different elements enter
into close union with each other, they form what Dalton
called " compound atoms," or, according to our present
nomenclature, " molecules " ; these are the ultimate con-
stituents of compound bodies.

Dalton's first scientific interests, which he preserved
through life, were connected with meteorology. He was
led to his chemical investigations through attempting to
find a reason for the uniformity in the mixture of gases
at different levels of the atmosphere, being much puzzled
to know why the oxygen, nitrogen, and aqueous vapour
did not arrange themselves in layers according to their
density, as when oil rises to the top if mixed with water.
His difficulty was mainly due to the peculiar ideas he had
formed of the nature of a gas. For a time he seems to
have adopted the correct view that all gases at the same
temperature and pressure have the same number of ultimate
particles in unit volume, but he abandoned it because ,it
did .not seem to Mm to lead to tfce observed .intenningjing
of gases irrespective of their density. ,IJe then invented
a , rather Janciful .hypothesis wl^ich drew a distinction between
the density of a& Atom and its weight, and he tried to
find -some connexion between the two. This led him
to investigate atomic weights. Dalton's temperament and
methods of procedure were different from those of the
other leaders of science whose work is under review. He
is rightly considered tP be tl^e originator of the principle

16 Britain's Heritage of Science

of multiple proportions, but he did not base his results
so much on accurate measurements, as on the logical
coherence of the system he advocated. In its simplest
form, this principle means that if one atom of an element
can combine with one, two, or more atoms of another, the
weight of the compound molecules formed must increase
by equal steps. But in the " New System of Chemical
Philosophy " (first published in 1810), though examples
are given in illustration, no systematic attempt is made to
reach an accuracy sufficient to establish a proof. To Dalton
the principle was obvious, and he was mainly interested in
determining the relative atomic weights and showing, for
a number of simple substances, how many atoms of each
element are combined to form the compound molecule.
The most important portion of the work deals with sub-
stances in which one or all of the combined elements are
gaseous, and he depends a good deal on the measurement
of volumes before and after combination. As the methods
of drying and otherwise purifying gases were imperfectly
understood at the time, the figures which he obtained were,
according to our standard, very inaccurate; nevertheless,
the power and success with which he treated the subject
very soon convinced other chemists that the foundations
of his system were correct.

Dalton's evidence was cumulative rather than indi-
vidually decisive, and it may be said that he convinced
the scientific world more by the strength of his own con-
victions than by the experimental proofs he supplied.

The total number of elements known in Dalton's time
was twenty-three, but others were soon added, until, towards
the middle of last century, over 'sixty elementary sub-
stances were recognized. At present -we have reason to
believe that the number' is strictly limited.1 Whatever
opposition there was to Dalton's views it. died. out quickly,
though some philosophers found much that was distasteful
in the immediate result of his teaching. There is, indeed,
at first sight, something repellent in the idea that there
should be one number, whether it be sixty-three or ninety-
two, raised in importance so far above all others that it

1 See the result of Moseley's researches, page 185,

John Dalton

From a painting by K. R.Faulkner
in the possession of the Poyal Society

John Dalton 17

fixes the limits of creation, as regards the possible diversity
of matter. But all such scruples must be set aside, for
the atom of Dalton is only a stepping-stone to a higher
level of knowledge. The chemist knows what he means
by an atom, and when he is building up his compounds
with them, he is not concerned with the question of their
ultimate constitution; just as the builder who constructs a
house with bricks need not trouble to enquire whether the
substance of the bricks is continuous or made of up of mole-
cules. The merit of Dalton fs atomic theory, like that of then
law of gravitation, is that it sets certain boundaries beyond L
which our imagination need not wander for the moment ; \
it defines a limited problem and for the time solves it.

Speculations on the nature of light could not fail to
attract the attention of the old philosophers; but, for our
present purpose, we need not go farther back than to the
rival theories of Newton and Huygens. The former — led,
no doubt, by his predilection for an accurately definable
starting point from which he could proceed to develop the
consequence of a theory with mathematical precision —
adopted the view (to be found already in the writings of
Democritus), that light consists of small corpuscles emitted
by the luminous body. The rectilinear propagation of light,
and its bending as it passes from one transparent body
to another, could easily be explained on this theory, and
though it was incapable of dealing with the more complex
properties of light, it received general support until the
middle of last century.

It was apparently Hooke who first suggested that light
was an undulatory motion in an all-pervading medium, but
Huygens has the merit of showing how this hypothesis could
explain luminous phenomena with a precision at least equal
to that of the corpuscular theory. There being at that
time no crucial test to decide between the rival theories,
the cleavage of scientific opinion took place along the line
of separation between metaphysical tendencies. Those who
disliked the idea of a vacuum and action at a distance
inclined towards Huygens, others towards Newton. Com-
promises have never been favoured by men of science, and
as the theory of gravitation starts from an assumption

B

18 Britain's Heritage of Science

implying action at a distance, those who were guided by
Newton considered it to be almost a sacrilege to go further
than the master. To them action at a distance became
an universal dogma, and the undulatory theory had no chance
until it could produce a conspicuous success by explaining
experimental facts, which were not amenable to treatment
by the more favoured hypothesis.

The analogy of light to sound attracted the attention
of Thomas Young (1773-1829), and was emphasized by
him in a paper published in the Philosophical Transactions
of the Royal Society in 1800. Here, again, it was the
detailed examination of one special aspect of the problem
which led to the decisive advance. Some of the charac-
teristic features of a wave motion may be illustrated by
an examination of the waves passing over a sheet of water.
Everyone is familiar with the circles spreading out from
a centre when a stone is thrown into water; each point
of the surface as the wave passes over it rising and falling
alternately. If two stones are thrown, and enter the water
at points near each other, each will start its own system
of circles. These will overlap, and the question arises :
how does the motion at any point of the surface of the
water depend on the motion due to each wave separately?
The question is so simple, and the answer seems so easy,
that many must have passed it by as hardly worth
recording; but Young saw that it was the key to the
position : each wave produces its own effect without inter-
ference from the other. If, under the influence of one set
of waves, a point were raised one inch above the undisturbed
level, and the other set caused by itself alone an elevation
of two inches, then the combined effect would be a rise of
three inches. If the effect of the second wave at any time
were a depression of two inches, the effect of the first being
the same as before, the depression of two inches would
overbalance the rise of one inch, and leave a depression
amounting to one inch. If the rise due to one set of
waves equals exactly the fall due to the other, there will
be neither a rise nor a fall, but the point will remain
at rest. This, in a few words, is the principle of " super-
position of motions," which applies only approximately to

Thomas Young 19

water waves, but generally to all small displacements such
as those we suppose to occur in the propagation of light.
The important point to notice is, that two rays of light
falling on the same point can neutralize each other's effect,
so that there is darkness, where each ray separately produced
illumination.

The colours of thin plates could not be explained onl
Newton's theory, unless the corpuscles of light were endowed /
with some peculiar attributes, and it occurred to Young
that a more natural explanation presented itself by con-
sidering the overlapping of waves which occurs whenever
two rays of light meet at a point. This led him to design
new experiments in which two sets of light waves could ^
be made to overlap in such a manner that the crest of
one set falls exactly over the hollow of the other, so that
the two waves neutralize each other. By measuring the
distances of the dark regions from each other, he showed
how the lengths of waves could be determined. All seemed
simple and straightforward, when a formidable difficulty
arose, through the discovery of a new property of light,
now called polarization. This seems to have baffled Young
to such an extent that he began to be doubtful of his
theory. It was only when the French engineer, Fresnel
(who rediscovered the cause of the " interference " of light
and corrected Young's explanation of " diffraction "), had,
in conjunction with Arago, formulated more precisely the
experimental conditions under which polarized light may
interfere, that the clue to the solution was found. In a
letter to Arago, dated 12th of January 1817, Young
suggested that the peculiarity of waves which gave rise
to polarization might be due to the direction in which the
motion takes place. In a wave of sound, each particle
of air moves backward and forward in the direction in
which the sound is propagated, so that if the sound
spreads out from one point, the motion is directed every-
where to or from the centre. In a wa er wave propagated
over a horizontal sheet of water, on the other hand, the
direction is mainly up and down. It occurred to Young
that if a wave of light resembled that spreading over a sheet
of water, two disturbances propagated in the same direction

B 2

20 Britain's Heritage of Science

might still show different effects, for if the wave comes
straight towards us the direction of motion might be hori-
zontal or vertical.

If the originality of a discovery can be gauged by the
opposition it rouses, Young's work takes a high rank. In
referring to his explanation of the interference of light—
(Edinburgh Review, Vol. I., p. 450) — Lord Brougham
expresses the opinion that it " contains nothing which
deserves the name either of experiment or discovery,"
and concludes by " entreating the attention of the Royal
Society, which has admitted of late so many hasty and
unsubstantial papers into its Transactions."

As regards the suggestion of transverse vibrations, one
might have imagined that the analogy of water waves
would have secured its being more readily accepted, but
the passage from two to three dimensions is by no means
obvious, and its difficulties presented themselves with
special force to mathematicians. When Fresnel had inde-
pendently recognized that the experimental facts could
not be explained except by accepting this transverse
motion, he placed the wave theory of light on a new
and firm basis ; but he lost the collaboration and sympathy
of his colleague Arago, who, up to the time of his death
in 1853, would not recognize the possibility of a spherical
wave in which the motion was not entirely radial. Even
Laplace and Poisson were strongly antagonistic to the idea
of spherical waves with transverse displacements ; their
difficulty was a very substantial one, solved only at a later
date by the investigations of Stokes.

Of all men who have spent their lives in the search for
experimental discoveries, no one has ever approached
Michael Faraday (1791-1867) in the number, the variety,
or the importance of the new facts disclosed by his labours.
If we wish to select from among these discoveries one or
two which have had a predominant influence in directing
scientific efforts into new channels, we must give the first
place to his researches on electro-magnetic induction.
Starting from the discovery that an electric current suddenly
generated or suddenly stopped caused an instantaneous
current in a wire placed in its neighbourhood, he proceeded

Michael Faraday 21

to show that a current passing through a wire which is
made to move in the neighbourhood of another circuit
induces similarly a current in the latter; and finally he
extended these facts to the effects of moving magnets in place
of electric currents. Faraday thus not only prepared the way
for a consistent theory of electro-magnetic action, but proved
that it was possible to convert electric energy into mecha-
nical power, or, reciprocally, obtain electric energy by an
expenditure of mechanical work. In other words, the whole
of the present electric industry is based on his discoveries.

As a second example of Faraday's experimental genius,
we may take his work on the chemical decomposition of a
liquid when an electric current is sent through it. Though
this process of electrolysis had been used with great success
by Sir Humphry Davy, its laws were not fully understood.
Faraday proved that the total quantity of the substance
decomposed depends only on the total quantity of electricity
which has passed, independently of whether it be a strong
current acting for a short time, or a weak current acting
for a correspondingly longer time. He also discovered a
most important relation between the amount decomposed
and the chemical constitution. In his own words : "If
we adopt the atomic theory and phraseology, then the
atoms of bodies which are equivalents to each other in
their ordinary chemical action, have equal quantities of
electricity naturally associated with them." How pregnant
these words are as forerunners of the most recent researches
in electricity will appear in due course.

During a long life Faraday piled his discoveries one
upon another in almost continuous succession, yet they
are united by a common thread of thought applied both
consistently and persistently. New facts were brought
to light, not through an omnivorous desire to penetrate
into detached bits of unexplored regions, but by the wish
to find a common link binding together all the forces which
in each branch of Physics — gravity, electricity, magnetism
and chemistry — had been treated as peculiar to that branch.
His manner of looking at things was so different from that
of other scientific men of his time, and in some ways so
prophetic, that a few words must be said with regard to

22 Britain's Heritage of Science

o

it, more especially as it was much more thorough-going
than is generally represented.

Matter is only known to us through the forces which
it exerts, and we cannot, therefore, reason about matter
at all, but only about forces. This truth was so strongly
impressed on Faraday's mind, that he warned scientific
men against the use of the word " atom," because it fixed
their attention on what he considered to be unessential. He
could only conceive centres of force and lines of force
emanating from these centres. Though all visible effects
are perceived at the termination of the lines, his whole
attention was fixed on the space which was filled by them.
He objected to all materialistic conceptions and looked upon
an all-pervading medium which had been invented to explain
the phenomena of light as an unnecessary and objectionable
imagination. He insisted that the lines of force which
spread out from a centre cannot be conceived to be made of
different stuff from the centres themselves, and that, therefore,
the aether, if it exist at all, must itself be made up of lines of
force emanating from separate centres. We may, perhaps,
regard this view as a dim foreshadowing of the most recent and
not yet firmly established views which have emerged from
the so-called principle of relativity. The vibration of light
Faraday tentatively suggested to be due to a vibration of
the line of force emanating from a centre, and therefore
forming an essential part of it. Each particle of matter
in his mind sends out tentacles through space, and when
two bits of matter seem to act on each other at a distance
they only appear to do so because their tentacles are in-
visible to us. During the closing days of his fertile" life

r he planned experiments — no doubt in connexion with his
-4 speculations on the nature of light — to test whether magnetic

*- force requires time for its propagation.

Our belief in the conservation of energy now forms the
foundation of our conception of nature, and we hold to it
more firmly than to anything else that science has taught
us. All the changes we witness in the material world are
merely transformations of one form of energy into another,
and these different forms can all be measured in the same
units. The principle of conservation asserts that energy

John Prescott Joule 23

is never lost or gained in any of these transformations,
the total quantity in the universe remaining the same.
The simplest kind of energy is that of a body in motion,
and is measured by half the product of the mass and the
square of the velocity. If a heavy body be allowed to drop
from a height, it increases its velocity as it falls, and strikes
the ground with a certain amount of energy. If that energy
has not been created, it must have existed already when
the body was placed at the height from which it fell. Hence
we must recognize some form of energy which depends on
the gravitational attraction between the earth and the
body. This potential energy, as we call it, is being trans-
formed into the energy of motion (kinetic energy) as the
body falls. These are the two great subdivisions of energy.
If heat be not a substance, as was generally believed till
the middle of last century, but a form of energy, a definite
quantity of heat should be equivalent to a definite amount
of energy ; so that whatever the means by which we trans-
form mechanical work into heat, we ought always to get
the same amount. That this conclusion is correct was esta-
blished by Joule's researches. It forms our first law of
thermodynamics .

John Prescott Joule1 (1818-1889) began his scientific
career at the age of nineteen, and already six years later
he had established his position as one of the greatest
benefactors of the community. The characteristic quality
of mind which enabled him without aid and without en-
couragement to accomplish so much was his ability to fix
on the essential factors of a problem, and to verify his
ideas by accurate measurements. Inspiration came to him
from his own experiments; his first ideas were hesitating
and sometimes wrong, but correcting them step by step, he
was led almost automatically to the final great discovery.
His cautious and strictly scientific procedure showed itself
at an age when an abundance of energy and originality so
often lead to ambitious speculations which are beyond the
powers of inexperienced youth. Joule published his first

1 A valuable account of Joule's fife and work, by Osborne Reynolds,
will be found in the Joule volume of the Manchester Literary and
Philosophical Society.

24 Britain's Heritage of Science

results in a series of letters addressed to Sturgeon's
" Annals of Electricity," and in the fourth of them he
gives us the guiding motive of his research.

" I can hardly doubt," he writes, " that electro-
magnetism will ultimately be substituted for steam to
propel machinery. If the power of the engine is in
proportion to the attractive force of its magnets, and
if this attraction is as the square of the electric force,
the economy will be in the direct ratio of the quantity
of electricity, and the cost of working the engine may
be reduced ad infinitum. It is, however, yet to be deter-
mined how far the effects of magnetic electricity may
disappoint these expectations."

Sturgeon's electro-magnetic engine which Joule tried to
improve was a very primitive machine. His first attempt
to render it more effective was not successful, as he admits ;
but what is remarkable is the strictly scientific manner in
which he measured the power by the weight the engine
could raise per minute. Joule next turned his attention
to the measurement of the electric power absorbed. He
designed and constructed a galvanometer for the purpose,
and as a first result discovered an important law (subse-
quently shown to be only approximately true), which appeared
to him to justify his belief in the future of the electro-magnetic
engine. The passage — -quoted above — in which he expresses
this belief shows, however, that consideration of the con-
servation of energy had not crossed his mind at that time,
and that he considered it possible to have an effective machine
the cost of working which may be reduced ad infinitum.
He had, nevertheless, some scruples about the effects of
" magnetic electricity," which may disappoint his expecta-
tions. He therefore directed his attention to these effects.
Referring to the impossibility of understanding experiments
made by different investigators, " which is partly due to
the arbitrary and vague numbers which are made to
characterize the electric current," he adopted a system of
units which can be reproduced anywhere, using the amount
of water decomposed per hour as the standard of current,
and the quantity of electricity delivered in one hour by the
unit current as the unit quantity.

John Prescott Joule 25

In a paper " On the Production of Heat by Voltaic
Electricity," he announced the most important law, that
heat generated in a circuit is proportional to the time, the
resistance and the square of the current.

In the early stages of his investigations, Joule tacitly
adopted the then accepted view that heat is a substance,
which could not be generated or destroyed, but he soon
altered his opinion. In 1843 he expressed himself as
follows : —

" The magnetic • electrical machine enables us to
convert mechanical power into heat by means of the
electric currents which are induced by it. And I have
little doubt that, by interposing an electro -magnetic
engine in the circuit of a battery, a diminution of the
heat evolved per equivalent of chemical change would
be the consequence, and this in proportion to the
mechanical power obtained."

It seems that Joule was not then aware of the previous
experiments by Count Rumford, in which heat had been
generated by means of mechanical work (see page 108).

He assumed a more decisive attitude in a subsequent
paper, which is introduced with the words : —

"It is pretty generally, I believe, taken for granted
that the electric forces which are put into play by the
magneto-electrical machine possess, throughout the whole
circuit, the same calorific properties as currents arising
from other sources. And indeed when we consider heat
not as a substance, but as a state of vibration, there appears
to be no reason why it should not be induced by an action
of a simply mechanical character, such, for instance, as
is presented in the revolution of a coil of wire before
the poles of a permanent magnet. At the same time, it
must be admitted that hitherto no experiments have
been made decisive of this very interesting question ; for
all of them refer to a particular part of the circuit only,
leaving it a matter of doubt whether the heat observed
was generated or merely transferred from the coils in which
the magneto -electricity was induced, the coils themselves
becoming cold. The latter view did not appear untenable
without further experiments. . . ,"

26 Britain's Heritage of Science

The crucial experiment was performed by Joule with the
result — again in his own words — " that we have therefore in
magneto-electricity an agent capable by simple mechanical
means of destroying or generating heat." The second part
of the same paper, entitled " On the Mechanical Value of
Heat," begins as follows : —

" Having proved that heat is generated by the magneto-
electrical machine, and that by means of the inductive
power of magnetism we can diminish or increase at
pleasure the heat due to chemical changes, it became an
object of great interest to enquire whether a constant
ratio existed between it and the mechanical power gained
or lost. For this purpose it was only necessary to repeat
some of the previous experiments and to ascertain, at the
same time, the mechanical force necessary in order to
turn the apparatus."
He thus finds that —

" The quantity of heat capable of increasing the
temperature of a pound of water by one degree of Fahren-
heit's scale is equal to, and may be converted into, a
mechanical force capable of raising 838 Ibs. to the
perpendicular height of one foot."

The particular method adopted to determine what we
now call the mechanical equivalent of heat was beset with
many experimental difficulties, and it is not therefore sur-
prising that his first result was nearly 9 per cent, in error.
Osborne Reynolds observed that the paragraph quoted really
overstates the conclusions Joule was entitled to draw, because
he has only shown that work could be converted into heat,
but not the inverse process, and that, at that time, he had
no clear ideas as to the conditions under which heat may be
converted into work. In fact he had dealt only with the
first law of thermodynamics, and it took some years before
the second law could be formulated with precision. It must
be remembered, however, that Joule was only twenty-five
years old at the time of his great discovery, and that he
was working alone, unsupported, and opposed by all the
prejudices of the recognized authorities.

It is not necessary to refer here in detail to the skill with
which Joule extended his investigations in many directions,

John Prescott Joule 27

generating heat by mechanical force in different manners,
but always finding the same equivalent, until no vestige of
doubt was left that all different forms of energy could be
expressed in the same units. His measurements became
more and more accurate, and such uncertainties as remained
in the numerical value of the equivalent were, in great part,
due to the difficulty of measuring the temperature with a
glass thermometer ; the accuracy obtained was indeed to
some extent the result of the accidental excellence of his
thermometers. A few years later the composition of glass
became much less suitable for scientific use.

It has already been noted that while the conversion
of mechanical work into heat was completely and satis-
factorily dealt with by Joule, the converse transformation
of heat into work involves further important considerations,
into which it was necessary to enter. Sadi Carnot had, in
1824, published a work entitled " Reflexions sur la puis-
sance motrice du feu, et sur les machines propres a developper
cette puissance," in which the subject was treated with
masterly perspicuity, but his reasoning was expressed in
the language of the material theory of heat. He was, however,
the first to point out that the mechanical production of
an effect by a heat engine is always accompanied by a
transference of heat from one body to another at a lower
temperature. Relying on the axiom that a perpetual motion
involving a continuous performance of work is impossible,
he laid down the conditions for a thermodynamic engine
which, with a given transference of heat, would do the
maximum amount of work. The peculiarity of such an
engine is, that whatever amount of work can be derived
from a certain transference of heat, an equal reverse thermal
effect will be produced if the same amount of work be spent
in working it backwards. Further, the work done by a
perfect heat-engine must be the same for the same trans-
ference of heat, whatever be the nature of the material
used. If heat be a form of energy, and not a substance,
it is clear that the amount which enters the cooler body
of an engine must be less than that which leaves the
hotter one, and that the difference is equivalent to the
mechanical work done in the passage. The position of

28 Britain's Heritage of Science

Joule was, therefore, necessarily antagonistic to Carnot's
assumption.

William Thomson (1824-1907), known to the present
generation as Lord Kelvin, while studying in Regnault's
laboratory in Paris, had become acquainted with the
important conclusions that may be drawn from Carnot's
thermodynamic cycle, and with the efforts which were being
made in France to verify the relations between the thermal
properties of substances which can be derived from it.
Though at first reluctant to abandon so fertile a principle,
and hesitating to give full assent to Joule's views, he soon
discovered that Carnot's reasoning may be modified so as to
bring it into harmony with the principle of the conservation
of energy. The same solution had occurred to Clausius, who,
anticipating Kelvin, was thus the first to give the correct
theory of the heat engine; but we are here concerned only
with the account of Kelvin's share in advancing the
subject; and a very magnificent share it was. His great
paper " On the Dynamical Theory of Heat," communicated
to the Royal Society of Edinburgh in 1851, places the whole
matter on a firm scientific basis, and establishes relations
between the physical properties of substances which have
all been verified experimentally. Full credit is given in
the paper to those who have contributed to, and, in part,
initiated, the ideas which led up to the final recognition
of the conservation of energy as the most fundamental
law of nature. What is called the second law of thermo-
dynamics is really the adaptation to thermodynamics
of the axiom expressing the impossibility of obtaining
a perpetual motion by a heat-engine. As formulated
by Lord Kelvin, it runs as follows : " It is impossible,
by means of inanimate material agency, to derive
mechanical effect from any portion of matter by cooling
it below the temperature of the coldest surrounding
objects."

Considerations leading up to a complementary principle
as important as that of the conservation of energy seem to
have been in Kelvin's mind at an early stage. If we imagine
a hot and a cold body, say, the boiler and condenser of a
steam engine, we may, by transferring the heat from the

William Thomson 29

first to the second, transform part of the thermal energy
into work, but only a certain definite portion, exactly
calculable in accordance with the second law and Carnot's
principle. But if we bring the hot and cold bodies into
actual contact with each other, and allow the heat to pass
directly from one to the other, without doing mechanical
work, their temperature will be equalized, and we shall have
lost for ever the possibility of utilizing the thermal energy
which has been transferred. There is, therefore, a funda-
mental difference between the transformation of mechanical
work into heat and the inverse transformation. In the
former case we may convert the whole mechanical energy
into heat, as when we rub two bodies together and raise
their temperature through friction, while, in the reverse
operation, when heat is transformed into work, only part
of that which leaves the source of heat is utilized. We must
therefore distinguish in the energy of a body a part which
is available for the performance of useful work, and another
part which is unavailable, the thermal energy of a body
containing only a definite proportion belonging to the first
category. Moreover, it is only the ideally perfect engine
that can utilize the whole of the available energy; in
machines such as those we can construct there is always a
further loss due to their imperfection. We must conclude
that in the constantly occurring processe3 in which heat is
allowed to pass from one piece of matter to another without
doing useful work, the quantity of available energy stored
in the universe is diminished. This leads us to the counter-
part of the principle of conservation, which is that of the
dissipation of energy. Among the wealth of achievements
contained in the intellectual heritage left us by Kelvin,
the discovery of this truth is pre-eminently the one which
stands out as a landmark to future generations. It was
first announced in 1852, and we may quote the main
conclusions as then formulated.

1. There is at present in the material world a universal
tendency to the dissipation of mechanical energy.

2. Any restoration of mechanical energy, without more
than an equivalent dissipation, is impossible in inanimate
material processes, and is probably never effected by means

30 Britain's Heritage of Science

of organized matter, either endowed with vegetable life, or
subject to the will of an animated creature.

3. Within a finite period of time past, the Earth must
have been, and within a finite period to come the Earth must
again be. unfit for the habitation of man as at present
constituted, unless operations have been, or are to be,
performed, which are impossible under the laws to which
the known operations going on at present in the material
world are subject.

The third of these statements must necessarily apply
not only to this earth but to the whole universe, and there
is therefore no escape from the conclusion that the material
universe, as we know it, is like a clockwork which is slowly
but steadily running down.

It was reserved to Clerk Maxwell to perceive the reason
of our inability to check the gradual degradation of energy.
Heat is essentially a disorderly motion, the particles of
matter in a body which is apparently at rest moving
irregularly in all directions. We are unable to convert this
irregular into a regular motion, and it is this limitation of
our powers which prevents our making full use of molecular
energy as a source of mechanical work. Speaking of the
second law of thermodynamics, Maxwell says : . . . .
" it is undoubtedly true, as long as we can deal with bodies
only in mass, and have no power of perceiving or handling
the separate molecules of which they are made up. But
if we conceive a being whose faculties are so sharpened that
he can follow every molecule in its course, such a being,
whose attributes are still as essentially finite as our own,
would be able to do what is at present impossible to us.
For we have seen that the molecules in a vessel full of air
at uniform temperature are moving with velocities by no
means uniform, though the mean velocity of any great
number of them, arbitrarily selected, is almost exactly
uniform. Now let us suppose that such a vessel is divided
into two portions, A and B, by a division in which there is
a small hole, and that a being, who can see the individual
molecules, opens and closes this hole so as to allow only
the swifter molecules to pass from A to B, and only the
slower ones to pass from B to A. He will thus, without

Clerk Maxwell 31

expenditure of work, raise the temperature of B and lower
that of A, in contradiction to the second law of thermo-
dynamics."

In the history of electrical science Maxwell (1831-1879)
stands in very much the same relative position to Faraday
as Lord Kelvin occupied towards Joule in the domain of
heat. They both brought pre-eminently mathematical minds
to bear on the results of experimental discoveries, and saw
more clearly than the original discoverers the important
consequences which flowed from their researches. Neither
Faraday nor Joule were experimentalists pure and simple,
they were indeed guided mainly by theoretical considera-
tions; but it lay beyond their object or powers to enter
fully into the wider generalizations, though Faraday showed
in the passages we have quoted that his imagination went
far beyond his immediate experimental results.

The theory of electrostatics which deals with electric
charges at rest, their distribution on conductors, and their
mutual attractions or repulsions, is explained in the simplest
manner by assuming the existence of two kinds of electricity,
for which it is convenient to retain the old names, positive
and negative electricity. The mechanical effects of the
charges may be dealt with mathematically very much as
we do in the case of gravitational attractions. There is
also a formal analogy between magnetic and electric actions,
so that independent magnetic fluids were sometimes intro-
duced to facilitate the treatment of magnetic problems.

Faraday saw that, if we wish to grasp the relationship
between the action of electric charges at rest and the electro-
dynamic effects produced by electricity in motion, and
more especially, if we wish to include in the same field of
enquiry the electric effects produced by moving magnets,
we must take a more comprehensive view. We must cease
to look at the centres or origin of the forces, and fix our
attention on the medium between them. This, as has already
been explained, was Faraday's outlook. Further, if the
effects of light and electricity are both transmitted through
a medium, our natural distaste to add unnecessarily to
the number of hypotheses inclines us to the belief that the
same medium serves bo:h purposes. But here a formidable

32 Britain's Heritage of Science

difficulty presented itself. The phenomena of light seemed
to be explained in a satisfactory manner by giving to the
aether the properties of ordinary incompressible elastic
bodies, though certain circumstances might have roused the
suspicion that we had not got hold of the whole truth. Yet
the essential points seemed so well accounted for by the
investigations of Green and Stokes, that there was every
reason to believe that outstanding difficulties would be
satisfactorily solved, without abandoning the substance of
the theory. It was quite clear, nevertheless, that the medium
invented to explain the properties of light, 'could not account
for the electrical effects.

It is here that Maxwell's genius saw the solution : the
problem had to be inverted. It was not the question of
whether a medium adapted to account for the comparatively
simple phenomena of light could explain electrical action,
but whether a medium constructed so as to explain electrical
action could also explain the phenomena of light. In
formulating the essential properties of the medium which
could produce the electrical effects, Maxwell had to fit a
mathematical mantle on the somewhat crude skeleton of
Faraday's creation. The task was formidable, and the
manner in which it was carried through stands unequalled
by any achievement in the whole range of scientific history,
both as regards its intellectual effort and its final results.
Only one of its successes need here be recorded. A quantity
of electricity may be measured either by its electrostatic,
when it is at rest, or by its electrodynamic effect, when it
is in motion. Looking separately at the two manifestations
of electricity, we are led to two different units in which it
can be measured, the so-called electrostatic and electro-
magnetic units. The time of propagation of an electro-
dynamic effect through space was proved by Maxwell to be
equal to the ratio of these two units. It could be calculated,
therefore, from purely electric measurements, and it turned
out to be exactly equal to the velocity of light. Hence
luminous and electrodynamic disturbances are propagated
with the same velocity, and we must conclude that their
nature is identical. There was, after the publication of
Maxwell's work, really nothing more to be said for the older

Michael Faraday

From a painting by A. Blakeley, in

the. fonKSPSKinn ni the. 7?mvi/ Snrietv*

Clerk Maxwell 33

view which gave to the aether the properties of elastic
solids.

Brought up in a school of physicists which based the
explanation of natural phenomena on perfectly defined
conceptions, and required, therefore, always a mechanical
model to represent properties of matter and force, Maxwell
in his first efforts tried to outline the mechanical construction
of the aether necessary to explain the electrical effects. He
conceived this aether, the ultimate elements of which retained
the properties of the cruder forms of matter, to be composed
of cells, each of which enclosed a gyrostatic nucleus.
Gradually, however, he abandoned these attempts at finding
a mechanical model for the aether, and was satisfied to rely
mainly on the mathematical formulae which expressed its
properties in the simplest way. In this he followed, or, to
be strictly accurate, helped to initiate, the modern tendency
of refusing to go beyond the immediate results of observa-
tion, relegating tacitly all questions of interpretation to the
domain of metaphysics; which means disregarding them
altogether. Maxwell's electrical work has revolutionized the
whole aspect of science ; and though undertaken in the purest
spirit of philosophic enquiry, it has led directly to the great
practical results which we see in the present applications of
wireless telegraphy.

It is seldom that it is given to one man to open out new
paths of thought in more than one direction. Newton's
theory of gravitation and his optical work is an example
of such a rare success, and there is perhaps no other equally
marked except that supplied by Maxwell. Though his
work on the constitution of gases may not have been as
far-reaching in its results as the monumental researches we
have already noted, it has introduced a new and original
idea into the treatment of the properties of matter.

Towards the middle of last century, Herapath had
revived the theory originally proposed by Daniel Bernoulli,
according to which the pressure of a gas is due to the impact
of its molecules against the sides of the vessel which contains
it, and Joule, adopting this view, had calculated the velocity of
the molecules of a gas from its known density and pressure.
Such calculations can only give us the measure of an

C

34 Britain's Heritage of Science

average. Through mutual collisions or otherwise, each
particle constantly changes its velocity both in magnitude
and direction, and it becomes important to determine the
law regulating the distribution of velocities. Maxwell's
classical investigation of this difficult problem has since
been modified in detail and extended, but the manner in
which he attacked it introduced an entirely novel method of
applying mathematical reasoning to physical phenomena.
Its results were decisive, and led to the discovery of new
experimental facts connected with the internal friction of
gases. When a metal disc is suspended from a wire passing
through its centre so that the plane of the disc is horizontal,
a twist imposed on the wire will cause the disc to perform
oscillations in its own plane, which diminish in magnitude
and gradually disappear owing to the internal friction of
the gas surrounding it. Maxwell's calculations led to the
unexpected result that this retarding effect should be the
same whatever the pressure of the gas, so that air at a
pressure of a few millimetres should diminish the motion of
the disc as rapidly as when it is at atmospheric pressure.
This surprising result was tested experimentally and found
to be correct.

We are naturally interested in the personal history of
those who have initiated new departures in science, and it
is more especially instructive to record the character of their
early education and the conditions under which they accom-
plished their work. Without entering into biographical
details, we may briefly state, so far as they have not already
been given, the essential facts in the lives of the great men
whose achievements have formed the subject of this chapter.

Isaac Newton, the posthumous son of a small freehold
farmer in Lincolnshire, is reported to have been — like Kepler —
a seven months' child. While attending school at Grantham,
he showed little disposition towards book learning, but
great aptitude for mechanical contrivances, and he amused
himself with the construction of windmills, water clocks, and
kites. Not being considered fit to be a farmer, he was
sent to the University of Cambridge in 1661, on the recom-
mendation oi an uncle who was a graduate of Trinity College.
He does not seem to have received much inspiration from

Clerk Maxwell, Isaac Newton 35

his teachers, but pursued his reading according to his own
choice, and it was Descartes' " Geometry " that inspired
his love for mathematics. In 1665, at the age of twenty-five,
he left Cambridge on account of the Plague, and it seems
that in this year the method of " fluxions," which contains
the germ of the differential calculus, first occurred to him.
Returning to Cambridge, he began his optical and chemical
experiments, and continued his mathematical researches at
the same time. In the year 1669, he was elected Lucasian
Professor of Mathematics, and chose Optics as the subject
of his first series of lectures. He continued his studies at
Cambridge, the " Principia " being published in 1687. As
a sign of national gratitude, Montague (afterwards Earl of
Halifax), then Chancellor of the Exchequer and at the same
time President of the Royal Society (1695-1698), offered
Newton the post of Warden of the Mint in 1695, and this
was followed five years later by his appointment to the
Mastership, which was then worth between £1,200 and
£1,500 per annum. Newton continued, however, to dis-
charge his professorial duties at Cambridge until 1701.
From 1703 onwards until his death, twenty-five years later,
he held the Presidency of the Royal Society.

One is tempted to look upon the quiet life of the old
Universities as being specially conducive to study and
research, but the times of active progress in the Universities
coincided rather with the periods when political disturbances
were sufficiently intense to penetrate these havens of rest.
Such a time was the end of the seventeenth century, when
the interference of James II. into University affairs was a
source of trouble both at Oxford and Cambridge. Newton
himself took an active part in defending the prerogatives
of the University. On a previous occasion he had taken the
side of the Senate against the Heads of Colleges in a dispute
about the Public Oratorship, and when in 1687 the King
issued a mandate that a certain Benedictine monk should
be admitted a Master of Arts without taking the oaths of
allegiance and supremacy, Newton was one of the deputies
appointed by the Senate to make representations to the
High Commissioners' Court at Westminster.

In recognition of the services rendered to the University,

C2

36 Britain's Heritage of Science

he was elected on two occasions as their representative in
Parliament. The interest which Newton displayed in
University politics illustrates his intellectual vigour, and
is inseparable from those qualities to which he owes his
commanding position in the history of science. While it is,
therefore, useless to speculate whether he was wise to allow
his attention to be diverted from his more serious work,
it is much to be regretted that his mind should have been
disturbed by discussions about priority which affected his
nervous system and damaged his health. These discussions
were forced upon him, and he would gladly have avoided
the bitter controversies with Hooke and, in later years,
with Leibnitz.

No two men could differ more in temperament or outlook
than Newton and John Dalton. To Newton the accurate
numerical agreement between the results of observation
and those of theory was of paramount importance, while
in Dalton's experiments, numerical results were mainly used
as illustrations of a theory which to him did not admit of
any doubt. John Dalton was the second son of a weaver
in poor circumstances living in Cumberland. In 1778,
when only twelve years old, he started teaching at the
Quaker School in Eaglesfield, where he himself had obtained
his first instruction. In this he was not successful, and
after a brief attempt at earning his living as a farmer, he
left his native village In 1781, in order to assist a cousin who
kept a school at Kendal. In 1793 he moved to Manchester,
where he spent the remainder of his life as a teacher of
mathematics and natural philosophy, first in " New College "
(which ultimately was transferred to Oxford as " Manchester
College "), and later privately. As early as 1787 he began
to keep a meteorological diary, which he continued to the
time of his death fifty-seven years later. He led the quiet
life of a student, interrupted by occasional visits to the
Lake District. In 1822 Dalton paid a short visit to Paris;
of London he remarked that it was " the most disagreeable
place on earth, for one of a contemplative turn, to reside in
constantly " In addition to the work which gained him
immortality, he foreshadowed several subsequent discoveries,
and enunciated the correct law of expansion of gases some

John Dalton, Thomas Young 37

months before Gay Lussac, without, however, ever giving
the numerical measurements required to prove the law.
He was affected by colour-blindness, and first examined that
defect scientifically. Dalton died in 1844, being then
seventy-eight years old.

Thomas Young was probably, next to Leonardo da
Vinci, the most versatile genius in history. He was
descended from a Quaker family of Milverton, Somerset, and
at the age of fourteen was acquainted with Latin, Greek,
French, Italian, Hebrew, Persian and Arabic. He studied
medicine in London, Edinburgh and Gottingen, and subse-
quently entered Emmanuel College, Cambridge. In 1799,
at the age of twenty-six, he established himself as a physi-
cian in London. Subsequently he held for two years the
Professorship of Physics at the Royal Institution, but
resigned, fearing that his duties might interfere with his
medical practice ; during the tenure of his Professorship he
delivered many lectures, which were subsequently published,
and contain numerous anticipations of later theories. In
1804 he was elected Foreign Secretary of the Royal Society,
and held that position for twenty-six years. In 1811
he became physician to St. George's Hospital, and Super-
intendent of the Nautical Almanac. His efforts to decipher
Egyptian hieroglyphic inscriptions were among the first that
were attended with success. His share in establishing the
undulatory theory of light has already been described, and his
claims as the founder of physiological optics will be discussed
in another chapter (p. 299). Thomas Young was a man
of private means, and not dependent on his medical practice
for a living. He died in London in the year 1829. To
quote Helmholtz :

" He was one of the most clear-sighted of men who
ever lived, but he had the misfortune to be too greatly
superior in sagacity to his contemporaries. They gazed
at him in astonishment, but could not always follow the
bold flights of his intellect."

Michael Faraday, the son of a working blacksmith, was
brought up in humble circumstances, and had but a
scanty school education. In 1804, at the age of thirteen,
he became an errand boy to a bookseller and stationer in

38 Britain's Heritage of Science

London, part of his duties being to carry round the news-
papers in the morning. After a year of probation he was
formally apprenticed to learn the art of bookbinding. It
was by reading some of the books that passed through his
hands that his mind was first attracted to science. Noticing
an advertisement in the streets announcing evening lectures
in Natural Philosophy with an admission fee of one shilling,
he obtained his master's permission to attend the lectures.
The account of his first connexion with the Royal Institution
may be given in his own words :

" When I was a bookseller's apprentice I was very
fond of experiment and very averse to trade. It
happened that a gentleman, a member of the Royal
Institution, took me to hear some of Sir H. Davy's
lectures in Albemarle Street. I took notes, and afterwards
wrote them out more fairly in a quarto volume.

" My desire to escape from Trade, which I thought
vicious and selfish, and to enter into the service of Science,
which I imagined made its pursuers amiable and liberal,
induced me at last to take the bold and simple step of writing
to Sir H. Davy, expressing my wishes, and a hope that,
if an opportunity came in his way, he would favour
my views ; at the same time, I sent the notes I had taken
of his lectures. . . . This took place at the end of
the year 1812, and early in 1813 he requested to see me,
and told me of the situation of assistant in the laboratory
of the Royal Institution, just then vacant.

" At the same time that he thus gratified my desires
as to scientific employment, he still advised me not to
give up the prospects I had before me, telling me that
Science was a harsh mistress ; and in a pecuniary point
of view but poorly rewarding those who devoted them-
selves to her service. He smiled at my notion of the
superior moral feelings of philosophic men, and said he
would leave me to the experience of a few years to set
me right on that matter.

" Finally, through his good efforts, I went to the
Royal Institution early in March of 1813 as assistant
in the laboratory ; and in October of the same year went
with him abroad as his assistant in experiments and

Michael Faraday 39

writing. I returned with him in April 1815, resumed
my studies in the Royal Institution, and have, as you
know, ever since remained there."

The journey abroad was a great event in Faraday's
life, as he became acquainted with many famous men of
science. Unfortunately his position was an unpleasant
one. At the last moment, Sir Humphry Davy's valet had
refused to leave the country, and Faraday had undertaken
to replace him until he could engage a substitute at Paris;
but no suitable person being found there, Faraday had to
continue in the menial work which did not form part of
the duties for which he was engaged. " I should have
little to complain of," wrote Faraday, in connexion with
this matter, " were I travelling with Sir Humphry alone,
or were Lady Davy like him." An interesting incident
took place during their stay at Geneva in the summer of
1814. During a shooting expedition, Faraday accompanied
the party in order to load Davy's gun, and De La Rive,
their host, accidentally entering into conversation with
him, found that the boy who had been dining with his
domestics was an intelligent man of science; accordingly
he invited Faraday to dine at his table. To this Lady
Davy strongly objected, and matters had to be compro-
mised by dinner being served for Faraday in a separate
room.

On his return home, after an absence of eighteen months,
Faraday was again engaged as an assistant at the Royal
Institution, and obtained some practice in lecturing at the
" City Philosophical Society." His independent scientific
work began in 1816, and was continued without interruption
until 1860. In 1827 Mr. Brande, who had succeeded Davy
as Professor of Chemistry at the Royal Institution, resigned
his position and Faraday was elected in his place, having
already, since 1825, occupied the position of Director of the
Laboratory. Faraday's emoluments were insufficient even
for his modest requirements, so that he had to supplement
them by undertaking private practice in chemical analysis
and expert work in the law courts; but though the income
which he thus secured was very substantial, he soon gave
it up, as he found it interfered with his scientific work.

40 Britain's Heritage of Science

In its place he accepted a lectureship at the Royal Academy
of Woolwich with a salary of £200. Subsequently, he was
made scientific adviser to Trinity House. At a later period
he was granted a Civil List pension of £300. Unselfish,
high-minded, and modest, Faraday enjoyed the confidence
of his friends, and declined all official honours. His out-
standing quality was his irrepressible enthusiasm for experi-
mental research. Foreign visitors to the laboratory relate
how, after a demonstration of one or other of his
discoveries, " his eyes lit up with fire," or how, when in
their turn, they showed him a striking experiment, he
danced around, and wished he could always live " under
the arches of light he had witnessed." Though interested
in all practical applications of science, he preferred to leave
their development to others.

" I have rather," he is reported to have said, " been

desirous of discovering new facts and new relations

dependent on magnetoelectric induction than of exalting

the force of those already obtained; being assured that

the latter would find their full development hereafter."

The importance of the electrical industries to-day prove

how brilliantly this assurance has been justified.

Joule's name appears to be derived from " Youlgrave,"
a village in Derbyshire where his family originally resided;
but his grandfather migrated to Salford and acquired wealth
as a brewer. When Joule was ten years old, his father
sent him, together with his elder brother, to study chemistry
under Dalton, who, however, during two years confined
his instruction entirely to elementary mathematics, and
before they could proceed to chemistry, Dalton was struck by
paralysis, and had to give up work. It has already been
explained how Joule was led to his final discoveries, starting
from the desire to utilize the power of electrodynamic
machines, which were then not more than interesting toys.
Towards the end of 1840, when Joule was only twenty -two
years of age, he forwarded a paper to the Royal Society
in which he announced the correct law indicating how the heat
developed in a wire through which a current of electricity
passes depends on the intensity of the current. That paper
was published in abstract in the Proceedings of the Royal

John Prescott Joule 41

Society, but full publication in the Transactions was
declined. A worse fate befell a later paper : "On the
Changes of Temperature produced by the Rarefaction and
Condensation of Air," read on June 20th, 1844, but not
printed by the Society even in abstract. Joule must
have felt severely disappointed at the time, but his dis-
position was so amiable and indulgent to human failings
that, at any rate in his later years, he did not show any
resentment. "I can quite understand," he once remarked,
" how it came about that the authorities of the Royal
Society refused my papers. They lived in London ; I lived
in Manchester ; and they naturally said : What good can
come out of a town where they dine in the middle of the
day ? "

Joule had not, however, to wait long for recognition;
he was elected a Fellow of the Royal Society in 1850, a year
before the same honour fell to Lord Kelvin and Stokes.
The turning point in his life came with the meeting of the
British Association at Oxford in June 1847, where he
described his experiments. According to Joule's account
that communication would have passed without comment
if a young man had not risen, and by his intelligent observa-
tions created a lively interest in the new theory of heat.
That man was William Thomson, afterwards Lord Kelvin,
whose recollection of the meeting differs, however, from that
of Joule.

" I heard," he writes some years later, " his paper
read at the sections, and felt strongly impelled to rise

and say that it must be wrong but as

I listened on and on, I saw that Joule has certainly a
great truth and a great discovery and a most important
measurement to bring forward. So, instead of rising
with my objection to the meeting, I waited till it was
over, and said my say to Joule himself at the end of
the meeting."

Whichever version of the incident be the correct one,
it led to a lifelong friendship, and marks the date at which
opposition to Joule's views began to break down. Faraday
was also present at the meeting, and was impressed by
Joule's work,

42 Britain's Heritage of Science

On the whole, Joule's life ran a smooth course. The
independent means of his father allowed him to devote
his whole time to scientific researches. He never took an
active share in the management of the brewery, but the
record of his observations of the pressure and temperature
of the air are often entered on the blank pages of the books
in which the stocks of barrels were kept. After his father's
death, unfortunate investments materially diminished his
income, and he was unable to undertake the heavy
expenditure involved in the prosecution of his researches
without some assistance from scientific societies with
funds available for research purposes. The grant of a
pension of £200 from the Civil List released him in 1878
from further anxieties. In private life Joule often
expressed his opinions strongly, but the kindness of his
character impressed all who came into contact with him,
and the modesty of the man who, as much as any one,
has placed experimental science in this country in the
commanding position it occupies, is typically illustrated
by the remark he made about himself two years before
his death : "I believe I have done two or three little things,
but nothing to make a fuss about."

William Thomson, born in 1824, was the second son of
James Thomson, who, at the time of his marriage, was
Professor of Mathematics in the " Academical Institution,"
Belfast. He was eight years old when his father took over
the Professorship in the same subject at the University of
Glasgow, and matriculated at that University at the early
age of ten. He entered as an undergraduate at Cambridge
in October, 1841, his first paper " On Fourier's Expansions
of Functions in Trigonometrical Series " having already been
published in the Cambridge Mathematical Journal in May
of the same year. The paper was apparently written during
a journey to Germany in the previous summer. No less
than thirteen additional papers were published by him in
the same journal during his undergraduate career, which
ended in 1845 with his graduation as second wrangler. In
the following year he was appointed Professor of Natural
Philosophy at Glasgow, a position which he held during
fifty-four years. From an early period he was recognized

John Prescott Joule, Lord Kelvin 43

as one of the greatest scientific intellects of his time, sur-
passed in power by none, in originality perhaps only by
Maxwell. Well merited honours came to him in rapid
succession. He was created a knight in 1866, General
Commander of the Victorian Order in 1896, and a Peer of
Great Britain as Lord Kelvin in 1892. The Royal Society
awarded to him the Copley Medal — their highest distinc-
tion— in 1883, and he occupied their Presidential Chair
between 1890 and 1895. He was one of the original members
of the Order of Merit, which was founded in 1902, and in
the same year was made a Privy Councillor. He was buried
in Westminster Abbey by the side of Newton.

Lord Kelvin's powers of work were prodigious and his
memory unequalled. He claimed to be able to take up at
any time the thread of an investigation which he had left
unfinished ten years previously. His brain was uninterruptedly
active ; his notebook handy on every railway journey, and
he could work till the late hours of an evening without
risking a sleepless night.

Everyone interested in the history of science must often
have asked himself the question how far its progress would
have been retarded if a particular brain had never been
called into existence. With few exceptions the answer
arrived at would be that, though discoveries might have-
been delayed and reached by different roads, and the work
of one man divided between two and three, the effect in the
long run would have been small and perhaps insignificant ;
but it is difficult to believe that science would stand where
it does to-day if Maxwell had never lived. Faraday's way
of looking at things was perhaps equally distinctive, but
Faraday's originality lay in the manner in which he was
led to perform the experiments which brought new facts
to light, and the same experiments might have suggested
themselves to others in a different manner. Maxwell's
originality of thought, on the other hand, was the essential
factor in the investigation, and it is almost impossible to see
how his results could have been arrived at by a different
road from that which he took. He also possessed another
power not always given to great intellects. A mind that
excels in originality is frequently unable or, at any rate,

44 Britain's Heritage of Science

unwilling to follow other men's lines of reasoning, and
thereby loses much of its power of fructifying contemporary
thought. But in Maxwell it was not only his originality,
but also his receptivity that was exceptional. No one was
less imitative, either in the manner of expression or in the
direction of his thoughts ; but he always knew how his own
way of looking at things was related to that of others.

We possess a good account of Maxwell's life,1 rendered
specially valuable by the number of his letters which are
reproduced; these allow us to get a glimpse of the
attractive quaintness with which he could illuminate every
subject, but the barest outline of his career must here
suffice.

His powers of observation showed themselves at a very
early age. In a letter, written when he was not yet three
years old, his mother relates that " Show me how it does "
was never out of his mouth, and that he investigated the
hidden courses of streams and bell wires. At school, he did
not at first take a very high place, and his schoolfellows
so much misunderstood the character of the reserved,
dreamy boy, that they gave him the nickname of " Dafty."
He soon, however, grew interested in his work, and ah1 his
letters home breathe a healthy playful spirit. When fourteen
years old he was taken by his father to attend some of the
meetings of the Royal Society of Edinburgh, and a year
later wrote a paper " On the Description of Oval Curves,"
which, on the recommendation of Professors Kelland and
Forbes, was published by that Society. At that time he
was already repeating for his own instruction experiments
on light and magnetism. He entered the University of Edin-
burgh in 1847 at the age of sixteen, and after remaining three
years entered Peterhouse at Cambridge, from which college,
however, he soon migrated to Trinity, graduating as second
wrangler in 1854. While still an undergraduate he pub-
lished a number of papers in the Cambridge and Dublin
Mathematical Journal ; from that time onwards his scientific
activity never ceased and gradually spread over a wider
and wider range of subjects.

1 "Life of James Clerk Maxwell,'5 by Lewis Campbell and William
Garnett (Macmillan, 1882),

Clerk Maxwell 45

In November 1856 Maxwell was appointed Professor of
Natural Philosophy at Marischal College, Aberdeen, a chair
which was abolished in 1860 in consequence of the fusion
of the two colleges in tha town. Among many characteristic
remarks which occur in his letters of that period we may
quote the following : "I found it useful at Aberdeen to tell
the students what parts of the subject they were not to
remember, but to get up and forget at once as being rudi-
mentary notions necessary to development, but requiring
to be sloughed off before maturity." Between 1860 and
1865 Clerk Maxwell taught Physics at King's College,
London. His duties there were exacting and he suffered
from two serious illnesses. He may have realized that his
powers of teaching did not lie in the direction of making
matters easy to students, many of whom were not over
anxious to learn, but it was probably mainly for reasons
of health that he resigned his chair and settled down at
Glenlair, the house built by his father on the family estate
in Dumfriesshire. A few years later he was, however,
persuaded with some difficulty to take over the newly-
established Professorship of Experimental Physics at Cam-
bridge. The Cavendish Laboratory was built in that
University by the Vllth Duke of Devonshire for the pro-
secution of experimental research in Physics ; it was opened
in 1870, and there probably never has been a benefaction
more fruitful in its results. The laboratory has, indeed, had
a brilliant history ; its immediate result was to allow Clerk
Maxwell to spend the closing years of his life among old
friends and new pupils. He died after a short but painful
illness in November 1879, at the age of forty-eight. Those
who knew him will hold his memory in affectionate remem-
brance, and to all who turn to his writings for a knowledge
of his work he will always remain a source of inspiration.

46 Britain's Heritage of Science

CHAPTER II

(Physical Science)

THE HERITAGE OF THE UNIVERSITIES
during the Seventeenth and Eighteenth Centuries

THE range of activity covered by University teaching
in the sixteenth century is indicated by the subjects
assigned to the five Regius Professorships founded in 1546
at Oxford and Cambridge by King Henry VIII. These
were Divinity, Hebrew, Greek, Civil Law, and Medicine,
the latter subject forming the only point of contact with
science. The practical demands of navigation were, how-
ever, beginning to stimulate the study of mathematics and
astronomy, and when Gresham College was founded in 1575,
separate professorships in these subjects were provided for.
A few years later (1583), Edinburgh appointed professors
of mathematics and natural philosophy, and Oxford followed
with the endowment of the Sedleian Professorship of Natural
Philosophy (1621), the Savilian Professorship of Geo-
metry (1619), the Savilian Professorship of Astronomy
(1621), and a Professorship of Botany (1669). During the
seventeenth century, Cambridge could only claim the
Lucasian Chair of Mathematics (1663), but it was the first
University with a Chair of Chemistry, endowed in 1702.
Its two Professorships of Astronomy were founded in 1704
and 1749 respectively. Chemistry and Botany being mainly
introduced as adjuncts to medicine, it appears that science
at the Universities may be said to have been confined to
the application of mathematics first to Astronomy, and
subsequently to other subjects, which, as they became more
definite began to supply material for* the exercise of mathe-
matical skill. Experimental science for its own sake began
to be taught at the Universities only in comparatively recent

Gresham College 47

times. On the other hand, it is well to dispose at once of
the erroneous impression that the British Universities were
bodies which confined themselves to the academic discussion
of abstruse subjects unrelated to the ordinary interests of the
community. The Universities trained the medical men.
who kept the flag of science flying in the eighteenth century,
and the study of astronomy was pursued in great part for
the sake of its value in finding the position of ships at sea,
and in the measurement of time. The problems dealt with
by mathematicians were, at first, generally suggested by
practical requirements, and only gradually became detached
from them. In fact, science began to be taught as a means
towards a practical end.

If Gresham College had developed — as it ought to have
done — into a University of London, it might have affected
the higher education of England at a critical time in a
manner which it is difficult now to estimate. Its founder,
Sir Thomas Gresham, had studied at Cambridge, and was
a man of exceptional abilities. He was admitted to the
Mercers' Company at the age of twenty-four, and soon
afterwards went to the Netherlands, where his father, a
leading London merchant, had business interests. By his
management of affairs in Amsterdam he helped King
Edward VI. over his private financial difficulties, and
received valuable grants of land as a reward. Under Queen
Elizabeth he continued to act as financial agent of the
Crown, and was knighted previous to his departure on a
mission to the Count of Parma. Having realized the utility
of the " Bourse " of Amsterdam during his residence in
Holland, he offered to build at his own expense what after-
wards became the Royal Exchange in London, if a suitable
plot of land were placed at his disposal. This was done,
and, in the upper part of the building erected, shops were
established, the rental for which was handed over to
Gresham. He then conceived the idea of converting his
own mansion in Bishopsgate into a seat of learning, and
endowing it with the revenues arising from the Royal
Exchange. Some correspondence about this scheme took
place in 1575, and after his death in 1579 it was found that
— subject to the life interest of his wife — he had provided

48 Britain's Heritage of Science

in his will for the foundation of a college. The first lectures
were given in 1597, each professor receiving the stipend
of £50, a sum somewhat larger than the revenue of the
Regius Professors at Oxford and Cambridge, which was
£40. The building contained residential quarters for the
professors, an observatory, a reading hall, and some alms-
houses. It ultimately proved to be too expensive to be
maintained with the available funds, and in 1768 was
handed over to the Crown; the lectures were then held
in the Royal Exchange until 1843, when the present building
was erected.

The appointment of the professors was, by Gresham's
will, vested in the Mayor and Corporation of London, who
in their first selection consulted the Universities of Oxford
and Cambridge, requesting them to nominate two candi-
dates for each of the seven professorships ; the final selection
included three graduates of Oxford, three of Cambridge,
and one who was a graduate of both Universities. The
first Professor of Geometry at Gresham College was Henry
Briggs (1561-1631), who, after the discovery of logarithms
by Napier, calculated complete tables, and thus made
their general use possible He also introduced the present
notation of decimal fractions, one of the most important
advances in the history of arithmetic. The last twelve
years of his life were spent at Oxford, where he held the
newly-founded Savilian Professorship of Geometry.

Edward Wright (1560-1615), a mathematician closely
associated with Napier and Briggs, translated into English
the Latin original of the work which contains the first
account of logarithms, but his name deserves chiefly to be
remembered in connexion with navigation, to which science
he rendered conspicuous service by laying the scientific
foundation of the method of constructing maps known as
** Mercator's Projection." Wright studied at Cambridge,
was elected to a fellowship of Caius College, and became a
teacher of mathematics in the service of the East India
Company.

Among those who, during the seventeenth century, held
professorships at Gresham College, we note John Greaves,
Isaac Barrow, Robert Hooke, Edward Gunter, Henry Gilli-

H. Briggs, E. Wright, J. Greaves, J. Barrow 49

brand, and Christopher Wren. Their work now calls for
consideration.

John Greaves (1602-1652), who held also for a time
the Savilian Professorship of Astronomy at Oxford, from
which position he was dismissed on political grounds in
1646, must be considered to be the earfiest scientific metro-
logist. He determined with fair accuracy the relation
between the Roman and English foot, and also carried out
some investigations on Roman weights. One of his suc-
cessors at Oxford, Edward Bernard (1638-1697), followed
up this work, and published a treatise on ancient weights
and measures.1

The mathematics of the time, as has already been noted,
was under the influence of Descartes, who had invented the
method of analytical geometry, in which the position of a
point is defined by its distance from two lines at right angles
to each other, and which represents a curve in the form of an
equation as an algebraic relationship between these distances.
When this is done, many problems suggest themselves,
such as that of forming the equation to its tangent at any
point, or calculating the area bounded by the curve.
The solution of such problems led naturally to the concep-
tions from which the differential calculus emerged. Isaac
Barrow (1630-1677), working along the lines indicated by
Fermat and Pascal, succeeded in finding the correct expres-
sion for the tangents of a number of curves. A successful
lecturer and writer of books, rather than an independent
discoverer, he was, nevertheless, an interesting figure in
the history of science. The son of a linendraper in London,
educated at Charterhouse, he proceeded to study medical
subjects as well as literature and astronomy at Cambridge,
where he took his degree and obtained a Fellowship at
Trinity College. Having been driven out of the University
by the persecution of the Independents, he travelled in
France and Italy, proceeding thence to Smyrna and Con-
stantinople. After spending a year in Turkey, he returned
home through Germany and Holland in 1659. In the
following year, he was appointed to the Chair of Greek at

1 See " Report of the Smithsonian Institution, 1890," " The Art
of Weighing and Measuring," by William Harkness.

D

50 Britain's Heritage of Science

Cambridge, and subsequently was elected Professor of
Astronomy at Gresham College. He returned to his Alma
Mater in 1663 to take up the newly-founded Lucasian
Professorship of Mathematics. Perhaps he performed his
most noteworthy scientific act when he resigned his chair
in favour of his pupil Newton.

John Wallis (1616-1703) is another example of a Univer-
sity Professor who took an active share in the national life.
After passing through Cambridge, where — like Barrow — he
studied medicine, he took Holy Orders in 1641, but became
involved in politics; he attained considerable facility in
deciphering intercepted despatches of the Royalists, and
thereby rendered considerable service to the Puritan party.
After holding several livings in succession, he was appointed
Savilian Professor of Geometry in 1649, in spite of the
opposition of the Independents, who resented his having
signed the protest against the execution of Charles I. John
Wallis was one of the foremost mathematicians of his time.
His work dealt chiefly with applications of Descartes'
analytical geometry; but he also published a book on
algebra. He seems to have been the first to conceive the idea
of representing geometrically the square root of a negative
quantity, and is the originator of the sign oo for infinity.
Other writings of his dealt with the tides. His efforts to
teach deaf mutes to speak, which are said to have been
successful, were the first attempts in that direction. Wallis
was also interested in investigations on sound, and in a paper
published in the Philosophical Transactions he communicated
some interesting experiments made by William Noble,
fellow of Merton College, and Thomas Pigot, Fellow of
Wadham, which contain important investigations on the
phenomenon of resonance in sound. Light bodies were
placed as riders to investigate the vibrations of stretched
wires, and it was shown that when these wires responded
to a higher harmonic, the riders were not set in motion if
placed at what we now call the nodal points.

Associated with the group of mathematicians who were
contemporaries of Newton, Lord Brouncker (1620-1684)
takes an intermediate place between the professional and
non-academic class. The title descended to him from his

John Wallis, Christopher Wren 51

father, who had been elevated to the peerage by Charles I.
Brouncker, after obtaining the degree of Doctor of Physic
in the University of Oxford, devoted himself to the study
of mathematics, and acquired a great reputation at home
and abroad by his investigations, which take a high rank
in the history of the subject. He made extensive use of
approximation by infinite series, and though he is not the
originator of continued fractions, he first used them
effectively. He was one of the original promoters of the
Royal Society, and was named as its President in the Charter.
He occupied that position for fifteen years, during which
he assiduously devoted himself to its duties. The first years
of the Society were necessarily critical ones, and much
credit for the judicious and successful direction of its affairs
is due to his distinguished services.

Christopher Wren (1632-1723), though known to fame
mainly as a great architect, distinguished himself at Oxford
as a mathematician. He had, independently of Newton,
suggested the existence of a universal attraction as the
cause which retained planets in their orbits, and is highly
spoken of in the " Principia." He also was the first to
calculate the length of the curve called the cycloid.

In 1657 he became Professor of Astronomy at Gresham
College, and three years later took over the Savilian Profes-
sorship at Oxford. Wren's contributions to science were
substantial. When the Royal Society expressed a wish
that mathematicians should investigate the laws of impact,
Huygens, Wallis and Wren sent in independent investiga-
tions. All these contained a correct appreciation of the
principle of conservation of momentum. The great archi-
tect's solution was correct so far as perfectly elastic bodies
were concerned. Wallis began with the consideration of
inelastic bodies, but ultimately treated the problem in the
most general manner, including both perfect and imperfect
elasticity.

A most striking instance of a family, who in many
successive generations reached distinction in the academic
world, may here be recorded. James Gregory (1638-1675),
educated at Aberdeen, published, at the age of twenty-
five, a treatise on optics, containing the invention of the

D 2,

52 Britain's Heritage of Science

reflecting telescope which goes by his name, but he had no
opportunity of actually constructing an instrument. He
was also the first to show how the distance of the sun
could be deduced by observations of the passage of Venus
across the disc of the sun. After a period of study at Padua
he became Professor of Mathematics at St. Andrews and
subsequently at Edinburgh. His elder brother, David Gregory
(1627-1720), was privately engaged in scientific pursuits,
and having used a barometer to predict the weather, paid
the penalty of his success by being accused of witchcraft.
David had three sons, the eldest of whom (1661-1708)
successively held the Chair of Mathematics at Edinburgh
and the Savilian Professorship of Astronomy at Oxford ;
the second son succeeded his elder brother in the Chair of
Mathematics at Edinburgh, and the third (Charles) was
Professor of Mathematics at St. Andrews. The eldest son
of David, the Savilian Professor, was Dean of Christ Church
and Professor of Modern History at Oxford.

Among the descendants of James Gregory we find in
three generations four distinguished medical men, all of
whom held professorships in the subject, and in the fourth
generation, two brothers, the elder of whom, William (1803-
1858), became Professor of Chemistry at the Andersonian
University in Glasgow, at King's College in Aberdeen, and
finally at Edinburgh University. His younger brother,
Duncan Farquharson Gregory, entered Trinity College.
Cambridge, assisted for a time the Professor of Chemistry,
but ultimately devoted his attention to mathematics, and
founded the Cambridge Mathematical Journal.

The scientific activity of the Universities in the second
half of the seventeenth century was naturally dominated
by the influence of Newton's work. His dynamical investi-
gations, leading up to the explanation of the observed motions
in the solar system, have already been described, and it
is interesting to trace the historical connexion between
those discoveries and others which remain to be mentioned.
Fortunately his own words describing the succession of
ideas as they occurred to him have been preserved :

" In the beginning of the year 1665 I found the

method of approximating series and the rule for deducing

David Gregory, Isaac Newton 53

any dignity of any binomial into such a series. The
same year, in May, I found the method of tangents of
Gregory and Slusius, and in November had the direct
method of fluxions, and the next year, in January, had
the theory of colours, and in May folio wing I had entrance
into the inverse method of fluxions. And the same year
I began to think of gravity extending to the orb of the
moon, and having found out how to estimate the force
with which a globe revolving within a sphere presses
the surface of the sphere, from Kepler's rule of the
periodical times of the planets being in a sesquialterate
proportion of their distances from the centres of their
orbs, I deduced that the forces which keep the planets
in their orbs must be reciprocally as the squares of their
distances from the centres about which they revolve;
and thereby compared the force requisite to keep the
moon in her orb with the force of gravity at the surface
of the earth, and found them answer pretty nearly.
All this was in the two Plague years of 1665 and 1666,
for in those days I was in the prime of my age for inven-
tion, and minded mathematics and philosophy more than
at any time since."1

In explanation of this passage it may be noted that the
" method of fluxions " was the foundation of the differential
calculus, and the " inverse method of fluxions " that of the
integral calculus.

Newton's attention was probably drawn to the study of
optics by Barrow. The change of direction of a ray of
light on entering a transparent body obliquely had been a
favourite subject of investigation in many countries, and
the law regulating it was first correctly formulated by Snell
(1591-1626), Professor of Mathematics at the University of
Leiden. It was reserved to Newton to show that ordinary
white light, such as sunlight, consisted of a mixture of
different rays. When transmitted through a prism it
spreads out into a band of coloured light called the spectrum,
because the different rays are deviated to a different degree.
With the same transparent material, the measure of the

1 From a MS. among the Portsmouth Papers, quoted in the
preface to the " Catalogue of the Portsmouth Papers."

54 Britain's Heritage of Science

deviation, or the refrangibility, as we should now call it,
is perfectly definite for each ray, and is intimately connected
with its colour. Having once separated a ray of definite
colour, no further refraction will alter that colour, and it
will continue to retain the same properties. As one of
the results of this discovery it became apparent that a lens
cannot form a perfect image of an object, because different
colours are not brought together at the same focus. This
appeared to Newton to be such a serious and irremediable
defect of telescopes with glass objectives, that he set himself
to construct an instrument in which the principal lens is
replaced by a mirror. At the request of the Royal Society,
who had heard of his telescope, Newton forwarded the
instrument to its secretary in December, 1671, with the
result that in January of the succeeding year he was elected
a Fellow of the Society. The idea of reflecting telescopes
had, as already mentioned, previously occurred to Gregory,
whose proposal differed, however, essentially from that of
Newton in the manner in which the rays were ultimately
brought to the observer's eye.

Newton's name is attached to the coloured rings seen
when two slightly curved surfaces of glass are brought
together, so that there is a thin circular wedge of air formed
near the point of contact. The explanation of these rings
presented considerable difficulties, especially with the theory
of light adopted by Newton. Though cognisant of the wave-
theory of light, which, as shown by Huygens, could explain
its propagation and refraction, Newton had good grounds for
not accepting it. He saw that the analogy of sound which
had been invoked in its favour broke down when applied
to the formation of shadows. Sound after passing through
an opening spreads in all directions, while light apparently
follows a straight course. In other words, sound can turn
a corner, while light seems unable to do so. More than a
century later, Fresnel gave the correct explanation of the
apparent discrepancy, showing that when the experimental
conditions were made to correspond, the analogy was main-
tained. It is necessary for the purpose that the relation
between the size of the aperture and the length of the wave
should be the same, and as the waves of light are very short,

Isaac Newton, Robert Hooke 55

either the aperture through which the light is made to enter
has to be very small, or the opening allowing the sound to
be transmitted must be large. In the latter case we get
" sound shadows," in the former the light spreads out just
as the sound does. But such refined considerations only
matured in the nineteenth century. In the meantime, the
ordinary laws of refraction and reflexion of light could be
satisfactorily explained by the corpuscular theory, which
seemed better able to cope with the formation of shadows,
and Newton therefore preferred the simpler theory. It is
unfortunate that an error of judgment, arising really from
superior knowledge, paralysed the progress of optics for
the time being, but this is the price which had to be paid
for the many benefits which accrued to science through the
confidence which Newton's work had inspired, and which
in all other cases proved to be justified.

Newton's work on light brought him into controversy
with Robert Hooke (1635-1703), a man of great genius but
unpleasant temperament, who, for a time, held the Chair
of Geometry at Gresham College. Hooke graduated at
Oxford and there came into contact with John Wilkins,
Thomas Wilkins and Robert Boyle. With an extraordinarily
prolific mind he touched on many subjects, insisting on
his priority in almost every new idea that was brought
forward by others.

In his " Micrographia " Hooke described important
observations on the nature of combustion and of flames.
Almost identical experiments were conducted by John
Mayow (1640-1679), a fellow of All Souls College, Oxford,
and it is impossible now to ascertain to whom they were
originally due. Mayow, who was also a distinguished
physiologist (see p. 296, Chapter XL), interpreted these ex-
periments with remarkable foresight. He truly recognized
that there must be a common element in air and in such
bodies as nitre, which readily give up their oxygen, and
showed that the air contains some constituent which is
consumed in combustion; he thus came very near anti-
cipating by more than a century Lavoisier's great discovery.

Hooke was the first who conceived the idea of regulating
watches by the balance wheel and spiral spring, and this

56 Britain's Heritage of Science

alone would give him a high place among discoverers. He
first constructed a spirit level, but others had anticipated
him in the use of the Vernier. He was the first to use light
powders to study the vibration of sounding bodies, and
invented an instrument to measure the depth of the sea. His
more theoretical speculations always showed acuteness,
and might have led to great things if he had been more
persevering. In 1674 he published views on a universal
gravitation which was to explain the planetary motions ;
with the exception of the law of the inverse square, these
contained the main principles of the theory which Newton
had then already worked out, though not published. In
optics, Hooke favoured the undulatory theory, and even
expressed the idea that the motion of the particles of the
medium which transmitted light was transverse to the direc-
tion of propagation, differing in this respect from the waves
of sound. Newton, who disliked controversies, is said to
have delayed the publication of his book on optics until after
Hooke's death for fear of rousing an acrimonious discussion.

The second edition of Newton's " Principia " was pub-
lished in 1713 by Cotes (1682-1716), a distinguished and
promising mathematician, who died at the early age of thirty-
four, having held during the last ten years of his life the
newly-founded Plumian Professorship at Cambridge.

Among the professional representatives of mathematics
during the eighteenth century, it must suffice to name
Maclaurin (1698-1746), Professor of Mathematics at Aberdeen ;
Matthew Stewart (1717-1785), who succeeded him in the
Professorship, and Thomas Simpson, the son of a grocer,
who ultimately became Professor of Mathematics at the
Royal Woolwich Academy.

After Newton had placed astronomy on a sound
dynamical foundation, a vast field was opened out to further
research. It had still to be proved that the law of gravita-
tion was sufficient to account for every detail of the motions
of celestial bodies, and was not only a first approximation
to be supplemented by other effects. Hence it became
necessary to increase the accuracy of astronomical observa-
tions, and to extend the theoretical investigations, based
on the laws of gravity, so as to include the mutual action

Isaac Newton, John Flamsteed 57

of planets on each other. We have now to consider the work
of some of the great men occupied in this task.

Flamsteed (1646-1720) does not strictly belong to the
academic circle, but as he was the first official representative
of astronomy in this country it is convenient to speak of his
work at this stage. Flamsteed began at an early age to take
an interest in astronomical observations. He entered Jesus
College, Cambridge, apparently with the object of taking
holy orders, but after obtaining his degree, influential friends
procured him an appointment as " King's astronomer."
About the same time, a Frenchman, called Le Sieur de S.
Pierre, visited England with proposals for improved methods
o£ determining longitudes at sea, and Flamsteed in a report
expressed the opinion that the project was impracticable,
because the position of the stars were not known with
sufficient accuracy. According to some manuscripts kept
at the Greenwich Observatory, when this came to the ears
of King Charles II, "he was startled at the assertion of the
fixed stars places being false in the catalogue, and said,
with some vehemence, he must have them anew observed,
examined and corrected, for the use of his seamen." This
incident was the immediate cause of the foundation of Green-
wich Observatory, the warrant for its building being issued
on June 12th, 1675. When it was completed, Flamsteed
set to work to form an improved star catalogue. Up to
that time, only observations with the naked eye had been
used to determine the positions of the stars, though
the cross wire and measuring micrometer had already been
invented by Gascoigne. Flamsteed realized the advantages
of applying the telescope in combination with a clock. But
he had to struggle against great disadvantages; his salary
was £100 a year, and he was provided by the Government
with neither assistants nor instruments. The latter had
to be provided by friends, or made at his own expense. In
spite of these difficulties he produced as a result of his labour
a star catalogue three times as extensive as, and six times
more accurate than, that of Tycho Brahe, which up till then
had been in use. Altogether he recorded the positions of
3,000 stars.

Flamsteed was succeeded at Greenwich by Edmund

58 Britain's Heritage of Science

Halley (1656-1742), who plays an important and interesting
part in the history of science. The son of a soap-boiler,
and educated at St. Paul's School and Queen's College,
Oxford, Halley, at the early age of nineteen, invented an
improved method for determining the elements of planetary
orbits. Finding that more accurate measurements of the
positions of fixed stars were necessary to the progress of
astronomy, and that this task was being satisfactorily
carried out at Greenwich for the northern heavens, he planned
a journey to catalogue some of the southern stars. Through
the good offices of the East India Company he obtained a
passage to St. Helena, but disappointed with the weather
conditions, he returned to England after having registered the
positions of about 300 stars. He was an ardent supporter
of Newton, and it was in great part due to Halley's efforts
that the " Principia " were published.

Halley was the first to take a comprehensive view of the
subject of Terrestrial Magnetism. Some advances had been
made in that subject since Gilbert's time, notably by Edward
Gunter (1581—1621), one of the early professors of astronomy
at Gresham College, who had taken regular observations of the
angle between the direction in which the magnetic needle
sets and the geographical north, and found a progressive change
in its amount. When the first observation was taken in
England, the needle pointed to the east of north; in 1657
it pointed due north, and the declination then gradually
increased towards the west. Henry Gellibrand (1597-1637)
continued and extended these observations.

In order to explain these slow changes called " the
secular variation of terrestrial magnetism," Halley formed
the theory that the earth is divided into an outer crust
and an inner nucleus, each part possessing its own inde-
pendent magnetic poles. A fluid layer was supposed to
separate the shell and the core, and Halley imagined the
latter to revolve with a slightly smaller velocity than the
former about a common axis. It is easy to see that if
we accept the premises, a suitable adjustment of the mag-
netic axes of the inner and outer parts of the earth would
lead to a slow revolution of the resulting magnetic axis.
This theory was recently renewed and extended by Henry

Edmund Halley 59

Wilde, and, though not generally accepted, it shows that
Halley recognized that the study of terrestrial magnetism
could yield important information on the constitution of
the earth and that he looked upon the subject from a
wider point of view than that of its mere application to the
purposes of navigation. The observations he took in two
journeys specially undertaken for the purpose of determining
the magnetic declination in different parts of the world, are
invaluable to us as historical records.

Halley's most important discoveries in astronomy were
the secular acceleration of the moon's mean motion, the
proper motion of the stars, and the periodicity of comets.
Comparing the dates at which certain total eclipses of the
sun had occurred, Halley could fix the times of the new
moon with sufficient accuracy to ascertain that the length
of the month was diminishing by about one-thirtieth of a
second per century. This implied that the moon's orbital
velocity is increasing and may be explained in accordance
with Newton's principles, partly as a result of an indirect
effect on the earth's orbit round the sun due to the attrac-
tion of planets, and partly by friction between the tides and
the solid parts of the earth, which increases the length of
the day, and indirectly reacts on the moon.

In all three of the discoveries mentioned, Halley made
extensive use of old records; it was by comparing the
observed distances of well-known stars from the ecliptic
with the observations of the Greek astronomers, that he
discovered their independent motions, and, similarly by
calculating the orbits of comets observed in previous
centuries, he found that some of them pursued nearly
identical paths. He concluded that though these were regis-
tered each time as new intruders into the solar systems,
they might only be reappearances of the same body. As an
example, he took the comet which had been observed at
intervals of about seventy-six years, and had last been seen
in 1682. He predicted that it would be seen again in 1758.
Halley did not live to see his prophecy come true : the
comet was actually observed on Christmas Day of that
year, and is now recognized as a permanent member of the
Solar System.

60 Britain's Heritage of Science

Halley succeeded Waller as Professor of Geometry at
Oxford in 1678, and Flamsteed as Astronomer Koyal in
1720. When he arrived at Greenwich, he found most of
the instruments removed, being the private property of his
predecessor. He procured some new ones, and began the series
of observations of the moon, the continuance and improve-
ment of which has always been the special care of the Royal
Observatory. But the age at which he took over his duties
prevented his making much progress.

Halley 's activity covered a large range of subjects, and
proved him to be a man of extensive knowledge and great
versatility. He investigated, independently of Mariotte,
the diminution of the pressure of air as we rise above the
surface of the earth, and gave the correct formula for
calculating differences in altitude from the barometric
records; he observed the aurora borealis, and connected
it with terrestrial magnetism by noting that the highest
point of the arch lies in the magnetic meridian. He gave
the generally accepted explanation of the cause of the
trade winds, but was less successful in his attempts to
improve the construction of thermometers ; he was the
first to give the formula which connects the position of
objects and images formed by lenses ; he formed an esti-
mate of the quantity of water vapour which enters the
atmosphere by the action of solar heat on the oceans; he
wrote on the effect of the refraction of air on astronomical
observations, worked out the method of deducing the
distance of the sun from observations on the transit of
Venus, and made valuable contributions to the method of
calculating logarithms. He improved the construction of
diving bells, and was the originator of " life statistics."
There are few men who can show a finer record of scientific
activity.

Halley was succeeded at Greenwich by Bradley (1692-
1762), to whom, according to the astronomer Delambre,
we owe the accuracy of modern astronomy. Bradley was
a nephew of John Pond (1669-1724), a clergyman who had
erected an astronomical observatory at his rectory of Wan-
stead in Essex, and done some meritorious work on the
satellites of Saturn and Jupiter. After graduating at Oxford,

Edmund Halley, James Bradley 61

Bradley went to reside with his uncle, and became interested
in astronomical work. His observational skill soon secured
results of sufficient importance to justify his election to the
fellowship of the Royal Society in 1718, and the appointment
to the Savilian Chair of Astronomy in 1721. He, however,
continued to live in Wanstead even after the death of his
uncle, visiting Oxford only for the delivery of his lectures.

It was known to Robert Hooke that the distance of the
stars might be ascertained by noting their change of position
at different times of the year, for as the earth revolves round
the sun, we look upon each star from a slightly different
point of view according to the position of the earth in its
orbit. The more remote the stars, the smaller will be the
displacement, and no one could tell beforehand whether
any of them were sufficiently near to show a measurable
effect. Hooke himself, with his accustomed impetuosity, had
tried the method, and using a star which for particular
reasons was specially fitted for the purpose, believed that he
had observed a comparatively large displacement. Samuel
Molyneux (see page 90) had erected a suitable telescope
at his house in Kew Green, for the purpose of verifying
Hooke's observations, and observed the same star on a
series of evenings during the early part of December, 1725,
but no material change of position was noted. At this
stage Bradley, a friend of Molyneux, began to take part
in the investigation. On visiting the Observatory at Kew
on December 17th, curiosity tempted him to take an observa-
tion, and he noted that the star had slightly increased in
declination. To his surprise, however, the displacement was
found to be in a direction opposite to that to be expected
if it were due to the proximity of the star. The apparent
movement was then continuously watched, and the star
was found to describe a closed curve, returning at the end of
a year's observation very nearly to its original position.
Bradley, much puzzled by the result, at first thought that
the displacement might be due to a periodic change in the
inclination of the earth's axis. In order to test this idea,
it was necessary to observe stars in different parts of the
sky, and Bradley set up a new instrument at his home in
Wanstead for the purpose. He found, indeed, that evesy

62 Britain's Heritage of Science

star examined described an elliptic curve similar to that
observed with Molyneux's telescope, but the difference?
in size and shape did not agree with the hypothesis he had
formed. At last the true explanation occurred to him.

Owing to the fact that light is not transmitted instanta-
neously, a star is not actually seen in the direction in which
it would appear if light took no time in its passage to the
earth The cause of this curious effect may be illustrated by
a familiar analogy. A person driving in a carriage during a
shower of rain on a windless day, though the drops fall
down vertically will feel them striking against his face, as if
he were meeting the wind. Hence, holding up an umbrella
to shield himself, he would have to tilt it forwards and if
he were unaware of his own motion, he would believe that the
drops fall at an angle slightly inclined to the vertical. Sub-
stituting Newton's corpuscles of light for the drops of rain,
it becomes clear that the velocity of the earth affects the
angle at which the light coming from a star seems to reach
us. This effect is called the " aberration of light." As the
earth's velocity changes in direction while it revolves round
the sun, a star, though stationary, will appear to describe
a closed curve. From the known velocity of the earth, and
the extent of a star's apparent motion, the velocity of light
may be calculated, and Bradley found it to agree closely
with that which had been calculated by Roemer from the
eclipses of Jupiter's satellites. The accuracy of Bradley 's
observations may be appreciated by noting that if the star's
position in the sky be such that it appears, owing to the
aberration of light, to describe a circle, the angular diameter
of the circle is about that of a halfpenny piece placed at a
distance of 420 feet; the dimensions of the curve described
by the star were measured by Bradley with an accuracy of
about two per cent.

After Bradley had established himself at Greenwich
Observatory, he continued his observations, and found that
the stars after a year's interval did not return to the same
position, as they ought to do if the aberration of light were
the only cause of their apparent displacement. Returning
to his original idea of a small change in the inclination of
the earth's axis, he then found it to account satisfactorily

James Bradley, Nevile Maskelyne 63

for this residual effect. He thus discovered the " nutation "
of the earth's axis, which is caused by an attractive effect
of the sun on the equatorial protuberance of the earth,
which is not an exact sphere, but a spheroid with a larger
equatorial than polar diameter.

When it is considered that every measurement of a star's
position has to be corrected so as to eliminate the effects of
aberration and nutation before its true position is ascer-
tained, Delambre's judgment that the accuracy of astro-
nomical observations owes everything to Bradley cannot
be gainsaid, and we shall also probably agree with the same
author1 that " ce double service assure a son auteur la place
la plus distinguee apres celle de Hipparque et de Kepler, et
au-dessus des plus grands astronomes de tousles ages et de
tous les pays."

After Bradley's death, Nathaniel Bliss, Savilian Professor
of Geometry at Oxford, was appointed Astronomer Royal,
but he only held the position for two years. Nevile
Maskelyne (1732-1811), a man of much greater ability,
next had charge of Greenwich Observatory. He graduated
as seventh wrangler at Cambridge in 1754, and twelve years
later was appointed to the post of Astronomer Royal, the
duties of which he discharged successfully during forty-
six years. His mind was first turned to astronomy as
a boy of sixteen by watching a solar eclipse. During a
voyage undertaken to observe the Transit of Venus, in
1761, he became interested in a process for determining
longitudes by measuring the distances of selected stars
from the moon, and he ultimately succeeded in introducing
this method as a regular practice in navigation. The im-
portance of the procedure consisted in its being independent
of timekeepers, and it consequently retained its place until
recently, when the construction of chronometers improved
so much that it lost its practical value.

In order to make the tabulations of the position of the
moon and of the selected stars readily accessible to navi-
gators, Maskelyne persuaded the Government to issue an
annual publication. This was the origin of the Nautical

1 Delambre, " Histoire de I'Astronomie au dix huiti&ne si&ele."

64 Britain's Heritage of Science

Almanac, which has proved to be of immeasurable value
to all seamen. Maskelyne remained its editor until his
death. He also re -organized in many ways the work and
instrumental equipment of the Greenwich Observatory, and
instituted an important research which led to the first
determination of the density of the earth. To appreciate
the importance of this experiment, we must remember
that by noting the rate of fall of a body we can measure the
force with which the earth attracts it, but not knowing the
total mass of the earth, we cannot tell how much one pound
of matter would attract another pound at a given distance.
That can only be ascertained by measuring the attraction
between masses both of which are known. From the result
of such a measurement the mass of the earth may be calcu-
lated, and as its dimensions are known, we can deduce its
mean density. The problem of finding the density of the
earth is, therefore, identical with that of finding the gravita-
tional attraction between known masses, and herein lies
its chief value. Maskelyne 's method consisted in deter-
mining the deflexion of a plumb line in the neighbourhood
of a mountain. As this deflexion cannot be observed directly,
we must have recourse to an indirect method; but this
presents no difficulties. If the latitudes of two places, one
to the north and the other to the south of a mountain,
be determined astronomically, and their distances directly
measured, the discrepancy between the observed and
measured differences of latitude gives us the data we want
for calculating the gravitational effect of the mountain.
The method cannot give very accurate results, as the density
of the material composing the mountain must be taken into
account, and this requires a geological survey and complicated
calculations. Maskelyne was assisted in his measurements,
which were conducted in the neighbourhood of the mountain
Schehallien in Perthshire, by Charles Hutton (1737-1823),
Professor of Mathematics at the Military Academy, Wool-
wich; the figures they obtained showed that bulk for bulk
the material of the earth is on the average between 4*48 and
5 -38 times heavier than water.

While learning at Oxford and Cambridge rapidly declined
after the first impulse of Newton's discoveries had died away,

William Cullen, Joseph Black 65

the reputation of academic science in the eighteenth century
is retrieved by the splendid record of the Scotch Univer-
sities, and notably of Edinburgh. It was indeed a brilliant
period in which Black originated quantitative chemistry,
Hutton founded the science of geology, Robert Simpson
taught mathematics, and John Robison, natural philosophy,
while Watt worked out his inventions, and in other branches
of knowledge Adam Smith and David Hume added to the
fame of their Universities.

William Cullen (1710-1790), who may be said to be the
founder of the Scotch school of chemists, studied at the
University of Glasgow, and at the age of nineteen obtained,
through the influence of friends, a post as surgeon on a
merchant ship sailing to the West Indies. On his return
home he became a medical practitioner in his native town,
Hamilton, but a small legacy enabled him to spend two
years at Edinburgh, in order to pass through a regular
course of study. After a period of activity in Glasgow,
during which he occupied the Chair of Medicine, and assisted
in founding the medical school in that university, he returned
to Edinburgh as Professor of Chemistry. Cullen was the
discoverer of the lowering of temperature which takes place
when a liquid evaporates, or a solid dissolves in a liquid.
He also experimented on the heat generated in chemical
transformations .

It was no doubt these researches on heat which directed
Joseph Black's attention to that subject. Black (1728-
1799) was the son of a Scotch wine merchant living at
Bordeaux. He was educated at Belfast, Glasgow and Edin-
burgh, studied medicine at the latter University, and
presented to it at the age of twenty-six an inaugural disser-
tation containing discoveries of fundamental importance to
chemistry. Limestone, which forms so important a portion
of the earth's surface layers, was at that time considered
to be an elementary substance. It was known, of course,
that at a high temperature its properties are changed; it
becomes quicklime, which gives off a great amount of heat
when brought into contact with water. This was explained
at the time by supposing that the limestone absorbed, when
heated, an imaginary thermal or caustic substance which

E

66 Britain's Heritage of Science

it gave out again when brought into contact with water.
The corresponding compound of magnesia behaved similarly,
and was not clearly distinguished from the calcium salt.
Magnesia had then already some importance as a drug,
and the title of Black's dissertation " De humoro acido a
cibis orto et magnesia alba " indicates that it was the medi-
cal aspect that led him to the research. Black proved that
the current explanation was wrong, and that, instead of
absorbing anything, limestone, on heating, lost in weight,
and gave out a gas, which he collected and identified with
Helmont's " gas sylvestre." He definitely proved that this
gas, now known as carbonic acid, differed from air, because
it could combine with caustic soda and potash, which air
could not; he also showed that atmospheric air always
contained small quantities of it. Black further established
the essential differences between the behaviour of calcium
and magnesium compounds. His use of the balance in
these researches justifies the claim that has been made on
his behalf of being the father of quantitative chemistry.

In his researches on heat, Black showed an equal power
of selecting the fundamentally important questions, and of
treating them with experimental skill and scientific precision.
His results were explained in his lectures, but many of them
remained unpublished until after his death It is, therefore,
not always easy to fix the dates at which his discoveries
were communicated to his students, so as to compare them
with similar results arrived at in other countries, notably
by Wilcke at Stockholm, and Deluc, who, born in 1727 at
Geneva, left his native town at the age of forty-three and
after various travels settled down in England, and died at
Windsor in 1817. There is no doubt, however, that Black
was the discoverer of latent heat. Deluc had noted the slow
melting of ice, and made the observation that when a mixture
of ice and water is heated, the temperature of the water
remains constant until all the ice is melted, but Black went
a good deal further, and not only measured the heat required
to melt the ice, but showed it to be the same in amount as
that which was set free in freezing the water. He applied
the term "latent heat," which is still in use, and his
measurements were correct to two per cent. The corre-

Joseph Black 67

spending phenomenon was observed when water was
converted into steam, but, owing to the greater experimental
difficulties, the numerical value obtained was not so accurate.
Black also had clear ideas on the differences in the amounts
of heat required to raise different substances through the
same range of temperature; but handed over this part of
the subject to his pupil Irvine.

An interesting paper by Black- on " The supposed effect
of boiling on water in disposing it to freeze more readily,
ascertained by experiments " (Phil. Trans. 1775) is worth
reading as an example of clear thinking, lucid description,
and good experimenting. It is still to-day the common
belief of plumbers, and those who derive their knowledge
of science from plumbers, that hot-water pipes freeze more
readily in winter than cold ones. This belief seems to have
had its origin in the report, made on good authority, that
when water is exposed at night in the dry atmosphere of
the Indian winter, in order to convert it into ice through
the loss of heat by radiation, it is essential to boil it
previously. In order to find the reason for this, Black exposed
two similar cups, one filled with boiled and the other with
unboiled water, to a temperature below the freezing point,
and saw, indeed, ice crystals appearing on the surface of
the former, while the latter remained clear. But on intro-
ducing thermometers, he discovered that the temperature
of the unboiled water had fallen below the freezing point,
without being converted into ice, which, however, formed
as soon as the water was stirred. Black was aware of
Fahrenheit's observation that water, when kept perfectly
quiescent, could be cooled considerably below the normal
temperature of freezing. The question that remained to
be solved was, therefore, this : why should the unboiled
water be more easily undercooled than that which had been
boiled? The only effect that boiling can have on the water
is to expel the absorbed air, and one might be tempted to
reason from the above experiment that the absorbed air
favours the undercooling. But this explanation is negatived
by the circumstance that Fahrenheit's experiments were
conducted in a vessel from which the air had been removed
by the air pump. Black, realizing, therefore, that water

E 2

68 Britain's Heritage of Science

deprived of its air could be undercooled as well as ordinary
water, concluded that the cause of the difference lay in the
act of re-absorbing the air. He suggested that the absorp-
tion caused (possibly through minute differences of tempera-
ture or density) sufficient circulation, or, as he expressed it,
" agitation " to prevent the undercooling. It is remarkable
that the subject has never been examined further, but
Black's explanation finds some support in the experiments
made by Thomas Graham, who showed that the admission
of air into a previously boiled and undercooled solution of
Glauber salt, set the crystallization going, and this was
traced to a slight diminution of the solubility of the salt
in water which contains air.

To Black must also be given a place in the history of
aeronautics, as he was the first to make the attempt to fill
a balloon with hydrogen; this was as early as 1767, two
years before Montgolfier made his first balloon ascent.

Black practised as a medical man ; he held for a time the
Chair of Anatomy and Chemistry at Glasgow, but distrustful
of his qualifications as a chemist, exchanged it for that of
Medicine. In 1766 he succeeded Cullen in the Professorship
of Medicine and Chemistry at Edinburgh. In private life
he was fond of painting; the weakness of his health is
probably responsible for a certain lack of energy which
sometimes led him to abandon his work when half finished,
and to leave many of his researches unpublished. " No man
had less nonsense in his head," said Adam Smith, " than
Black."

One further contribution of the Scotch Universities to
chemistry remains to be noticed. Rutherford (1749-1819),
a medical man who occupied the Chair of Botany at Edin-
burgh, was the first to isolate the gas nitrogen in 1772, by
burning substances in an enclosed volume of air, and
absorbing the carbonic acid formed in the combustion.

Black's lectures were edited after his death by John
Hobison (1739-1805), a man of great intellectual powers,
who, like so many other men of science of the time, led an
eventful life. After a brief period of study at Glasgow, he
became tutor to the son of Admiral Knowles, who as a
midshipman was about to accompany General Wolfe to

Joseph Black, John Robison 69

Quebec. Robison took part in the war, and after his return
home was charged by the Board of Longitude to under-
take a journey to the West Indies for the purpose of
testing a chronometer constructed by John Harrison. A
few years later Robison accompanied, as private secretary,
Admiral Knowles to Petrograd, on his appointment as
President of the Russian Board of Admiralty. For a time
he also held the mathematical professorship attached to the
cadet corps of nobles at Petrograd. Before he went to Russia
Robison had occupied during four years the Chair of
Chemistry at Glasgow, and after his return home in 1773 he
became Professor of Natural Philosophy at Edinburgh.
When the Royal Society of Edinburgh received its charter
in 1783 he was elected secretary, and held this position until
within a few years of his death, which took place in 1805.

Robison enjoyed a high reputation among his contem-
poraries, but we cannot assign any great advance in science
to him. He was a man of great learning and published
researches, which only just fell short of marking a distinct
step. He deserves to be remembered even if it were only
for his connexion with James Watt, who owed him much
assistance and encouragement. Robison was always inter-
ested in steam, and had, before Watt's improvement of the
steam engine, conceived the idea of applying the power
of steam to the propulsion of vehicles.

David Brewster collated some of the manuscripts left by
Robison, and published them in a work of four volumes :
" Elements of Mechanical Philosophy."

It appears from this work that Robison undertook
several researches, which he omitted to publish. Among
them was an experimental investigation on the law of action
of electrical forces. This, he states, was communicated to
a " public society " in 1769, some years before Cavendish
and Coulomb discovered the law of the inverse square. The
experiments which are described in the published work,
lead unmistakably to that law, but it is not stated whether
they were the original ones or were repeated and improved
upon later. Robison makes no claim in this respect, but
refers to Cavendish as having " with singular sagacity and
address, employed his mathematical knowledge in a way

70 Britain's Heritage of Science

that opened the road to a much further and more scientific
prosecution of the discovery, if it can be called by that
name," and finally adopts Coulomb's measurements as con-
clusive. It seems, however, to have escaped notice hitherto
that Robison in his experiments used what must be con-
sidered to be the first absolute electrometer, the electric
force being balanced by the action of gravity, and there-
fore reducible to its value in terms of dynamical units.

Robison was a strong adherent of Boscovich, the Italian
philosopher, who tried to dispose of the difficulties inherent
in the definition of matter by considering atoms to be merely
centres of forces without extension. Boscovich had applied
his theory to the effects of ponderable matter on the trans-
mission of light, and Robison took up this subject and treated
it in a paper (Ed. Phil. Trans., Vol. II., 1790), which in
many ways is remarkable. Its title, " On the motion of light
as affected by refracting and reflecting substances which are in
motion," shows that it deals with one of the most puzzling and
difficult problems of physics . It was the phenomenon of aberra-
tion of fight discovered by Bradley which gave practical im-
portance to the subject, and, without entering into details, it
deserves to be recorded that Robison had the idea of apply-
ing telescopes filled with water to clear up experimentally
some of the obscure points, which up to our own times have
puzzled mathematicians. This idea was revived and success-
fully applied later by Airy, but Robison failed on account
of the difficulty of obtaining water that was sufficiently
transparent. Although his ideas are now superseded, the
paper gives us some idea of the powers of the man of whom
Watt wrote : "He was a man of the clearest head and the
most science of anybody I have ever known."

Robison's successor, both in the Chair of Physics and
as Secretary of the Royal Society of Edinburgh, was John
Playfair (1748-1819), previously Professor of Mathematics,
who had taken part in the geological survey connected
with the Schehallien experiment of Maskelyne and Robert
Hutton. His first work was a book on " Button's Theory
of the Earth," which had considerable influence in making
James Button's geological theories known and appreciated.
His mathematical contribution to science is mainly con-

Robison, Desaguliers, Robert Smith 71

fined to a publication " On the Arithmetic of Impossible
Quantities."

Though but little work of importance was produced at
Oxford and Cambridge in the eighteenth century, science
was kept alive. John Theophilus Desaguliers (1683-1744),
the son of a French Protestant clergyman, who left his
country on the revocation of the Edict of Nantes, was
brought to England while an infant. He studied at Oxford
and acted as Professor of Physics in that University. He
settled in London in 1712, and ultimately became Chaplain
to the Prince of Wales. After leaving Oxford, he became
a voluminous writer on many subjects. In his first paper
he describes a new method of building chimneys so as to
prevent their smoking. He invented a machine for measur-
ing the depth of the sea and other mechanical contrivances.
He is best remembered by his electrical work in which he
clearly defined the nature of a conductor as distinguished
from bodies which could be electrified by friction with-
out being attached to insulating handles. He enjoyed a
great reputation, being consulted by men of science, and
notably by James Watt in connexion with steam engines,
having himself introduced some improvements in their
construction.

At Cambridge, Robert Smith (1689-1768), as Plumian
Professor, made some valuable contributions to acoustics,
published in a separate volume — " Harmonics." His great
treatise on light contains a wealth of information, and still
possesses considerable historical interest. It had a great
influence at the time, stimulating the study of optics, more
especially with regard to its practical applications in the
construction of optical instruments.

72 Britain's Heritage of Science

CHAPTER III

(Physical Science)

THE NON-ACADEMIC HERITAGE
during the Seventeenth and Eighteenth Centuries

THE scientific investigator should be endowed with
knowledge, critical judgment, and inventive power.
For the first two attributes we must look mainly to pro-
fessional men, who have gone through a recognized training
and are engaged in teaching or research. Such men, brought
up under the compelling influence of accepted currents of
thought, though well prepared to advance their subject
and even to make new discoveries along the paths opened
out by their predecessors, are heavily handicapped when
the time has come for a revolution of fundamental ideas.
Often they have risen to the occasion, and thrown anti-
quated doctrines overboard, but sometimes the academic
tradition is strong enough to prevail. The advantage, then,
lies with those who are not burdened by the weight of
inherited opinions, and great opportunities are offered to
the inexperienced youth or the enthusiastic amateur. What
constitutes an amateur ? All efforts to define the term
must fail, because we cannot define what is not definite.
The word in its literal sense denotes a man who pursues
a subject for the love of it, but it carries a suggestion of weak-
ness, or rather a suspicion, associated more particularly
with amateurs in art, that they have not completely mastered
their craft. So far as the actual work of research is con-
cerned the difference between the amateur and professional
man is not always pronounced, and is frequently obliterated ;
some University professors have retained through life the
characteristic attributes of free lances of science, and

The Hon. Robert Bovle

From a -baintinp bv F. K

Robert Boyle 73

amateurs have occasionally rivalled professional scholars in
profundity of knowledge and academic conservatism.

The essential distinction — and it is an important one —
lies in the wider range of subjects which the professional
man of science has to cover. He may have to lecture or
advise students on matters which are outside his own
researches, or he may have to direct an institution burdened
with a quantity of routine work which cannot be neglected.
He both gains and loses by the exigencies of his duties ; while
his compulsory reading may supply him with analogies which
are frequently fertile in valuable suggestions, he is often drawn
away to side issues, and is tempted to adopt a dogmatic
attitude on those portions of his subject which he teaches
or directs, but is not much interested in.

The non-academic class of workers are free from any
routine which they do not impose on themselves and, as
might be expected, present less uniformity in their aims and
modes of working. What greater contrast could, indeed,
be found than that between the three men whose work
forms the main subject of this chapter : Robert Boyle,
the indefatigable experimenter and voluminous writer, who,
though refusing a peerage and the Presidency of the Royal
Society, found his chief pleasure in intercourse with other
men of science : Henry Cavendish, the taciturn recluse, who
disliked contact with the ordinary affairs of life, and was
remiss even in publishing his revolutionizing researches;
William Herschel, the poor Hanoverian oboist, who had to
earn his living as a teacher of music, and fight his way
up until, with telescopes constructed by his own hands, he
attained unrivalled pre-eminence as an astronomer.

Robert Boyle (1627-1691) belonged to an old Hereford-
shire family, whose name is mentioned in Domesday Book
as Biuville. His father, Richard, described by Thomas Birch
as one of the greatest men of his age, passed through a
course of study at Cambridge, and having spent some time
in London as a student of the Middle Temple, went to
Ireland to make his fortune, married a rich wife, and ulti-
mately became Baron of Youghall, Viscount of Dungarvan
and Earl of Cork. He was married twice and had fifteen
children. Robert, the last but one of them, received his

74 Britain's Heritage of Science

education partly at Eton, and then privately at his father's
newly-purchased property near Stalbridge in Dorsetshire.
At the age of eleven he was sent on a lengthy journey to
the continent, accompanied by an elder brother and a
French tutor, Marcombes; they reached Geneva, where
they stayed nearly two years before proceeding to Italy.
At Florence, Boyle became acquainted with the works of
Galileo, and one can imagine the impression the death of
that great man, which occurred during his stay, must have
made on his youthful mind. The party proceeded to Rome,
and ultimately set out on their return journey, but found
themselves at Marseilles without means, as a remittance
from Boyle's father had been stolen by the messenger.
Almost penniless, they made their way back to Geneva,
M. Marcombes' native place, and ultimately the two
brothers reached England in the summer of 1644. They
found their father dead, and the country in such confusion
that it was nearly four months before Robert Boyle, who
inherited the manor at Stalbridge, could make his way
thither.1 In London, Robert Boyle made the acquaintance
of John Wallis, Christopher Wren, and other distinguished
men, whose weekly meetings were destined to lead to the
foundation of the Royal Society. Though his scientific
studies were interrupted by an enforced visit to his dis-
ordered Irish estates, which extended over two years, he
settled down in 1654 at Oxford, where, during the following
fourteen years, he devoted himself entirely to scientific
research. He spent the remainder of his life in London,
taking an active part in the affairs of the Royal Society
until two years before his death. Boyle had strong religious
views; but he refused to take orders on the ground that
he felt no inner call, and thereby lost the appointment as
Provost of Eton. He so strictly interpreted the command
of the New Testament not to swear " neither by heaven,
nor by earth, nor by any other oath," that he refused the
Presidency of the Royal Society, because the Charter pre-
scribed the taking of an oath on his accession to office. By
his will he founded the " Boyle Lectures " for the defence

1 " Dictionary of National Biography."

Robert Boyle 75

of Christianity. He was never strong in health; weak
eyesight troubled him throughout life, and a painful disease
caused him much suffering in later years.

His scientific work is distinguished by great experi-
mental skill, and a determination to remain free from the
bias of preconceived notions. In his travels he had
become proficient in several languages, and he continued
to keep himself informed of what was being done on the
continent of Europe. Having read an account of Guericke's
air-pump (or, as Boyle calls it, " wind-pump "), he set
to work to construct one, and with the help of Robert
Hooke, who appears to have acted as his assistant at that
period, succeeded in effecting considerable improvements.
With this pump a large number of experiments were per-
formed, all devised to prove some definite point, such as
comparing the weight of air with that of water, or inves-
tigating what he calls the spring of air. He showed that
flames are extinguished and hot coal ceases to glow in a
partial vacuum. He proved that magnetic and electric
actions persist in his exhausted receiver, and that warm
water begins to boil under reduced pressure. The action
of the pump in removing air from a vessel suggested the
inverse process of increasing the pressure, and this led to
the construction of the compression pump. In his measure-
ments he attained considerable accuracy; the specific
gravity of mercury was correctly determined to one half
per cent., that of air to about 20 per cent.

Boyle's name is associated with the important law
connecting the density of air with its pressure. The proof
of the law is contained in a long paper entitled " Defence
of the doctrine touching the spring and weight of air,"
published in 1662. The range of pressures covered by the
experiments extended from four atmospheres (involving
the use of glass tubes ten feet long) down to 1J inches of
mercury; the agreement between observed pressures and.
those calculated from the changes of volume, assuming that
density and pressure are proportional, was quite sufficient
to prove the correctness of the law. The often repeated
assertion that it was Townley who first drew Boyle's
attention to the significance of these observations and for-

76 Britain's Heritage of Science

mulated the law is not justified, and is founded apparently
on some misconception of a passage in Boyle's account of
his experiments.

We owe to Boyle the use of the term " barometer,"
and he constructed an instrument in which the mercury
is replaced by a short column of water with sufficient air
above to counter-balance the atmospheric pressure. When
no temperature changes interfere, such an instrument
would be considerably more sensitive than an ordinary
barometer. With it Boyle could observe the difference of
pressure between the roof and floor of Westminster Abbey,
thus confirming Pascal's experiment without having to
ascend a mountain.

In his optical experiments Boyle showed that colours
are produced by a modification of the light which takes place
at the surface of the coloured body. The connexion between
radiant heat and light was illustrated by covering half of a tile
with black and the other half with white paint, when he
found that in sunlight the black paint becomes hot while
the white remains cold. He also first drew attention to the
colours of thin films such as soap bubbles. He investigated
freezing mixtures and discovered that when salt is added to
snow or ice the observed cooling is connected with the lique-
faction of the salt. Boyle invented the hydrometer and
showed how to determine by means of it specific gravities not
only of liquids but also of solids. He made extensive chemi-
cal experiments, and correctly explained a chemical reaction
as being due to the substitution of an atom of one kind for
an atom of another kind in the original compound.

Boyle's completed works occupy six folio volumes;
he is somewhat prolix in his discussions, but his descrip-
tions are always clear and interesting. By the manner
in which he allows himself to be led from one experiment
to another he almost reminds one of Faraday, though his
indiscriminate mixing of what is important with what is
of minor value partakes a little of the weakness of the
dilettante. He was highly esteemed by his contemporaries,
and Newton, as well as many other eminent men of science,
showed, in their correspondence, that they attached great
value to his opinions.

Robert Boyle, Brooke Taylor 77

It is comparatively rare to find an eminent mathema-
tician among amateurs, but a noteworthy example is
furnished by Brooke Taylor (1685-1731), a wealthy man
who, having completed his studies, soon acquired a reputa-
tion by his researches, and was elected into the Royal
Society in 1712; two years later, he became one of the
secretaries of that body. Taylor's theorem is known to
every student of mathematics; in the subject of mathe-
matical physics we owe to him the formula which connects
the period of vibration of a stretched string with its length,
cross-section and tension.

The meetings of the Royal Society in the early days
of its activity were only partly occupied by the reading
of papers. Experiments were shown and discussed, and
new subjects were proposed for investigation; particular
questions were occasionally assigned to individual Fellows
for enquiry and report. In this manner scientific research
was organized more successfully than has ever since been
possible. To assist the Society's work, a curator was
appointed, whose special duties consisted in preparing the
experiments for the meetings. A wide range of subjects
was therefore brought to the notice of the meetings in an
attractive form, and we find that many Fellows extended
their researches in consequence of the stimulus received
at the meetings. The inducement to do so was more
especially strong with those who acted as curators, and this
may be one of the reasons why Robert Hooke, the first
who occupied that position, touched upon such a variety
of subjects in widely different fields of enquiry. Among
those who were employed at the beginning of the eighteenth
century to prepare experiments, though he does not seem
to have received the title of curator, was Francis Hauksbee,
to whom we owe many interesting observations. Passing
a strong current of air over the reservoir of a barometer,
he found that the height of the column of mercury dimi-
nished by two inches, thus proving the reduction of pressure
accompanying the increase of kinetic energy in fluid
motion. He connected this observation with the fall of
the barometer during a gale of wind. He was the first
who investigated the transmission of sound through water,

78 Britain's Heritage of Science

and made some interesting experiments on the intensity of
sound transmitted through air of different densities.

Hauksbee deserves, perhaps, most to be remembered
by his researches in electricity. Frequent references occur
in the publications of the time to the curious luminosity
in the partial vacuum above the barometer column which
occasionally appears when the mercury is made to oscillate
in the dark. Hauksbee had the idea that the luminosity
was connected with some electrical action. To test this,
he mounted a spherical glass vessel so that it could be made
to rotate round a central axis. The vessel was exhausted,
and, being set in motion, became highly electrified by
friction when the hand was placed against it. At the same
time the remnant of air in the vessel became luminous,
and Hauksbee rightly concluded that the luminosity was of
the same nature as that observed in the barometer; in
the latter case, of course, the friction is produced internally
between the moving mercury and the glass. Incidentally
it may be mentioned that the first record of an electric
spark occurs in Hauksbee 's writing; it was produced by
approaching the finger towards the electrified glass vessel,
and is said to have been an inch long.

Very little is known about the life of Hauksbee, or of
that of Stephen Gray and Granville Wheler, two other
important contributors to our knowledge of electricity.
Gray, elected a Fellow of the Royal Society in 1732, was
the first to point out the effects of conductivity in electrical
experiments, classifying bodies as conductors or insulators.
He had been led to this fundamental distinction by
experimenting with a glass tube which was closed at one
end by a cork, and noting that, when the glass was excited
by friction, the cork attracted light bodies, thus showing
that it had become electrified. When a rod several feet
in length carrying an ivory sphere at its further end was
inserted in the cork, the sphere also became electrified.
When other experiments did not give the expected result,
Gray seems to have consulted another Fellow of the Royal
Society, Granville Wheler, a clergyman, who suggested to
him that the cause of the failure was likely to be due to the
difficulty of supporting the bodies experimented upon in

Francis Hauksbee, Robert Symmer 79

such a manner that the electricity could not escape to
earth. He advised the use of silk threads, as owing to
their thinness they were likely not to conduct so well.
This proved to be successful, not for the reason given
but because silk is an excellent non-conductor. Besides
silk, other substances like glass and resins were recognized as
insulators, and the range of experimentation was thereby
much enlarged.

There was at the time considerable confusion owing to
the capricious manner in which electrical forces showed
themselves, sometimes by attraction and sometimes by
repulsion. No progress could be made in this respect until
Dufay, a Captain in the French army, showed in the year
1733 that these apparently contradictory effects could be
explained by assuming the existence of two kinds of elec-
tricity, which he called vitreous and resinous, terms which
in our own time Lord Kelvin used in preference to the more
common nomenclature of positive and negative electricity.
Dufay's experiments attracted little attention, and Franklin,
two years later, formed independently a theory, which
admitted only one kind, but distinguished between an excess
and defect of that kind. Bodies were called positively and
negatively electrified according as they contained an excess
or deficiency.

Another Fellow of the Royal Society, Robert Symmer,
also apparently unaware of Dufay's work, revived in 1759
the theory of two separate kinds of electricity with opposite
properties, and he was for some time supposed to be its first
originator. He did much to promote clear and definite
notions on electrical matters and the merit of his investigations
cannot be called in question. Though the controversies
between the followers of Franklin and those of Dufay and
Symmer lasted until quite recent times, they could not lead
to any substantial result because there is no fundamental
difference between the two views. Both emphasize the
distinction between two opposite electrical states, and our
preference for one or other alternative depends mainly on
the ideas which we unconsciously attach to forms of expression
which suggest more than they are intended to do. As a
matter of convenience, we may think of positive and negative

80 Britain's Heritage of Science

electricity without committing ourselves to any definite
theory as to their ultimate nature.

When the primary phenomena of static electricity had
been established, the further progress took its natural and
regular course. Experimental appliances had to be improved,
and instruments constructed suitable for quantitative measure-
ments. In this work John Canton (1718-1772), a private
schoolmaster, took an active and successful part. He
increased the efficiency of electrical machines by coating
the friction cushion, which was pressed against the glass
cylinder, with an amalgam of mercury. For the coarser
indicators of electricity, such as that which Gray had used,
Canton substituted two small spheres of pith or cork,
suspended from threads, which diverged when the spheres
became electrified.

Canton was also successful in other fields of science; we
owe to him the first experimental demonstration that water
is compressible, and the discovery of a new phosphorescent
body which he prepared by the action of sulphur on oyster
shells. William Henley, a linen-draper residing in London,
who reached sufficient distinction to be admitted to the
fellowship of the Royal Society, also constructed an electro-
scope intended for quantitative measurements. He was
chiefly interested in thunderstorms and atmospheric elec-
tricity generally, and noted the positive electrification of
the air in a dry fog. Greater importance is to be attached
to Abraham Bennett (1756-1799), a clergyman residing in
the Midland counties, who introduced the gold-leaf electro-
scope, the most sensitive instrument invented up to that
time for the detection of small quantities of electricity.
Simultaneously with Volta, he showed how the electric
condensers could be used in conjunction with electrometers
so as to increase their effectiveness. This led him to invent
an instrument called a duplicator which in principle is
identical with Lord Kelvin's replenisher ; but as it contained
conductors covered with shellac for purposes of insulation,
irregularities in its action interfered with the experiments.
In spite of these defects it was the embryo of our modern
" influence " machine. William Nicholson (1753-1815), to
whom further reference will be made (p. 107), cured most of

John Canton, Henry Cavendish 81

the defects of Bennett's doubler and converted it into an in-
strument which ought to have come into more extensive use.

William Watson (1715-1787), who started life as an
apothecary, but reached sufficient distinction as a medical
man to obtain the honour of knighthood, improved the
Leyden jar by substituting tin-foil for the liquid which till
then had formed the inner coating. In his experiments with
these jars he was much assisted by Dr. John Bevis (1695-
1771), another medical man, who was, however, mainly
interested in astronomical work, and also deserves to be men-
tioned as being the first to make a glass containing borax,
and to note that its refractive power was thereby increased.
Dr. Ingenhouse, a Dutch doctor settled in England, conducted
many electrical experiments, and claimed to have been the
first to replace the glass cylinder used in electrical machines
by a disc. The same claim is, however, made by others both
in France and Germany, and, among Englishmen, by Jesse
Ramsden, the optician and instrument maker, of whom more
will have to be said presently, and who certainly first brought
glass-plate machines into general use.

On a higher plane stand the researches of Henry Cavendish
which now demand our consideration. A paper published
in the " Philosophical Transactions " contains the foundation
of the mathematical theory of electrostatics. There were
probably but few mathematicians at the time interested in the
subject, and the experimental part of the enquiry, which
might have directed more general attention to the importance
of the work, was not published until a century later. The
mathematical investigation showed that if the whole of the
electricity communicated to a body collects at its surface,
none entering the interior, it necessarily follows that the
repulsion between two quantities of electricity must diminish
with increasing distance according to the same law as that
of gravitation. No other law would lead to the same result.
Robison appreciated the importance of this investigation
(see p. 69), but, like others, he was ignorant of the unpublished
experiments which Cavendish had actually made on the
subject. These verified with a sufficient degree of accuracy
that the charge of a body in electrostatic equilibrium resides
at the surface, and that if any part of it penetrates into the

P

82 Britain's Heritage of Science

interior, it can only be a small fraction. Fortunately the
manuscripts of Cavendish's electrical experiments have been
preserved, and were placed in the hands of Clerk Maxwell
when he took over the Professorship of Experimental Physics
at Cambridge. Their subsequent publication throws quite
a new light on Cavendish's importance as a physicist, giving
evidence of a wonderfully balanced combination of theoretical
power and experimental skill. Adverting to the many
instances in which Cavendish neglected to publish results of
importance, Maxwell1 remarks :

" Cavendish cared more for investigation than for
publication. He would undertake the most laborious
researches in order to clear up a difficulty which no one
but himself could appreciate, or was even aware of, and
we cannot doubt that the result of his enquiries, when
successful, gave him a certain degree of satisfaction.
But it did not excite in him that desire to communicate
the discovery to others which, in the case of ordinary men
of science, generally ensures the publication of their
results. How completely these researches of Cavendish
remained unknown to other men of science is shown by
the external history of electricity. "

This is not the place to enter into the details of the various
researches which were edited by Maxwell in 1879. Suffice
it to say that Cavendish measured experimentally the
electrostatic capacity of bodies, anticipating Faraday in the
discovery of the difference of the inductive capacities of
various substances, and Ohm in showing that the electric
current is proportional to the electromotive force. He also
compared the electric resistance of iron with that of rain
water and of different salt solutions. All this was done
by means of a rough electroscope and without a galvanometer.
He converted, in fact, his nervous system into a galvanometer,
by comparing the electric shocks received when Leyden jars
were discharged through various conductors, altering the
length of the conductors until the shocks were estimated
to be equal. He obtained astonishingly accurate results
with such simple and almost primitive means.

1 " The Electrical Researches of the Hon. Henry Cavendish,"
Introduction, p. xlv.

Henry Cavendish 83

The second of the two electrical papers which Cavendish
communicated to the Royal Society attracted considerable
attention, and though it does not deal with any matter which
we should now consider of fundamental importance, it shows
how far Cavendish was in advance of his time in appreciating
electrical matters correctly. The shocks which certain fishes,
such as the torpedo,1 are capable of giving to those who touch
them had been known for some time, and John Walsh, a
Member of Parliament and Fellow of the Royal Society, had
described some experiments showing the conditions under
which the shocks were received. He suggested that they
were of an electrical character. The idea was not generally
accepted, and was even laughed at on the ground that a
fish immersed in sea water, which conducts electricity, could
not be electrically charged. In answer to this objection,
Cavendish actually constructed an imitation torpedo and
demonstrated to an assembly of scientific friends the possi-
bility of obtaining shocks even when it was immersed in salt
water.

Maxwell remarks that this is the only recorded occasion
on which Cavendish admitted visitors to his laboratory.

Henry Cavendish was born in 1731 ; he entered Peterhouse,
Cambridge, in 1749, and left that University four years later
without taking his degree. He was elected a Fellow of the
Royal Society in 1760 and died in 1810. His father, Lord
Charles Cavendish, third son of William, second Duke of
Devonshire, was interested in scientific subjects and published
a paper on the capillary depression of mercury in glass tubes,
which was highly spoken of by Franklin; he was also the
first to construct maximum and minimum thermometers,
and received the Copley medal of the Royal Society for the
invention of these useful instruments. We may infer
that the mind of Henry Cavendish was first directed towards
science by his father's example. He lived on an allowance
of £500 until he was about forty years of age, when through
the death of an uncle he acquired a fortune which made him

1 The "word " torpedo " comes from the Italian, and is derived
from "torpor;" the name was given to the fish on account of the
numbness caused by the electric shock felt on touching it. The
torpedo is not now generally associated with torpor.

F 2

84 Britain's Heritage of Science

one of the richest men of his time, without altering the simple
mode of life to which he had become accustomed. It has
been said of him that his chief object in life was to avoid
the attention of his fellows; " his dinner was ordered daily
by a note placed on the hall-table, and his women servants
were instructed to keep out of his sight on pain of dismissal."1

There is some evidence, however, that in his intercourse
with scientific men he was not equally reticent. He attended
the meetings of the Royal Society regularly, dined nearly every
Thursday with the Philosophical Club, composed of some
of the Fellows, and in 1772 was an energetic member of a
committee formed to consider the best means of securing a
powder magazine against the danger of lightning.

Some of Cavendish's most remarkable results were de-
rived from experiments on gases. Such investigations then
tested the skill of an experimenter to a degree which is not
easily realized at present. To the difficulties of isolating,
purifying, and examining the chemical properties of these
invisible substances was added the mystifying belief in the
imaginary body, phlogiston, which was supposed to be
expelled hi - every act of combustion, and to account for
flame and fire.

From the purely experimental point of view a great
advance was made when gases were collected over mercury
instead of over water, which had been the usual practice.
The credit of this is due to Joseph Priestley (1733-1804), a
Nonconformist minister, who, having renounced his early
Calvinism and become a Unitarian, was then in charge of
Mil] Hill Chapel, Leeds ; subsequently he moved to Birming-
ham. Priestley held strong political views, which he expressed
freely, and these, together with his unorthodox opinions,
frequently got him into trouble. He wrote against England's
attitude towards the American colonies, and sympathized with
the French revolutionists. When he attended a dinner
arranged to celebrate the anniversary of the taking of the
Bastille, the mob burned his chapel and sacked his house.
He then went to live in London for a few years, but ultimately
emigrated to America. We owe to Priestley the discovery of

1 " Encyclopaedia Britannica."

Henry Cavendish, Joseph Priestley 85

a number of gases, and he first prepared oxygen by heating
oxide of mercury with a burning glass. He obtained hydro-
chloric acid by heating spirits of salt, sulphur di-oxide
by the action of sulphuric acid on mercury, and ammonia
by heating spirits of hartshorn. Cavendish's attention was
attracted by an observation of Waltire, who worked with
Priestley, that when a mixture of hydrogen and common
air was fired, dew appeared on the walls of the glass
tubes. This was explained as being a condensation of
water which had been present as vapour in the original
gases. But Cavendish was able to prove that the water
formed was really the result of the combustion of oxygen
and hydrogen. In order to interpret correctly the lan-
guage in which chemists expressed their results at the
time we must remember that oxygen was referred to as
" dephlogisticated air," nitrogen as " phlogisticated air,"
and hydrogen as " phlogiston." Cavendish therefore ex-
presses his result by saying " that water consisted of
dephlogisticated air united with phlogiston." The conclusion
embodies the discovery of the composition of water, which
till then was unknown.

Similar experiments seem to have been made by James
Watt, who subsequently claimed priority, but we need not
here enter into the discussions to which the dispute gave
rise, and which passed without interfering with the subse-
quent friendly intercourse between Cavendish and Watt.

A remarkable research originated in the interest which
Cavendish took in the composition of the terrestrial atmo-
sphere. By burning various bodies in measured volumes
of air, he satisfied himself that the amount of oxygen
present was the same in all the samples experimented upon.
He noticed, however, that in one of the experiments in
which a mixture of hydrogen and oxygen was fired by an
electric spark, the resulting water contained nitric acid.
This, Cavendish attributed to a remnant of atmospheric
nitrogen in the oxygen used, and, following up the matter,
showed that nitrogen and oxygen actually did combine
under the influence of an electric spark. Absorbing the
nitric acid formed, he could observe a shrinkage of volume
when sparks were passed through mixtures of nitrogen and

86 Britain's Heritage of Science

oxygen. He then put himself the question, " whether
there are not in reality many different substances com-
pounded together by us under the name of phlogisticated
air ? " and to satisfy himself on that point, he investigated
whether the whole of the air could be transformed into
nitric acid by combination with oxygen. He found that
there was, indeed, a small portion, estimated by him as
y^-o of the whole, which resisted the change. This remnant
undoubtedly consisted of argon, a separate gas, identified as a
new element only in our own times. The amount of argon
actually present in the air agrees remarkably well with
Cavendish's estimate of his residual gas.

There are many investigations on heat, unpublished at
the time, by which Cavendish anticipated Black in the
discovery of latent heat; he also determined the specific
heats of a number of bodies. Another important research
remains to be noted. A Yorkshire clergyman, John
Michell, had conceived the brilliant and ambitious idea of
measuring directly the gravitational attraction between two
spheres of lead. It has already been remarked, in con-
nexion with the Schehallien experiment of Maskelyne and
Hutton, that the average density of the earth may be
derived from such a measurement, but quite apart from
this application, the attempt to demonstrate Newton's
gravitational force within the four walls of a room con-
stitutes an effort of heroic ambition and remarkable fore-
sight. John Michell had constructed all the necessary
apparatus, including the torsion balance, which he had
invented for the purpose. Infirmities of age prevented his
carrying out the work, and at his death the apparatus fell
into the hands of another distinguished clergyman, Francis
John Hyde Wollaston (brother of the celebrated chemist),
who, at the time, held the Jacksonian Professorship at
Cambridge. Wollaston deserves considerable credit for
handing over the execution of the experiment to the one
living man who was capable of bringing it to a successful
issue. The original torsion balance consisted of a wooden
beam about two yards long, weighing 5J ounces, and
carrying at each of its ends a leaden sphere two inches in
diameter. Cavendish substituted for the beam a metal rod

J

John Clerk Maxwell

From an engraving in "Nature "
by G. J. Stodart of a photograph

hv FP.Y&US ni Crl.fi.<icrniti

John Michell 87

strengthened by a copper wire which acted as a tie to pre-
vent bending, and was attached to a vertical suspension.

On being slightly displaced from its position of equili-
brium the torsion of the wire by which it was suspended
would tend to bring the horizontal beam back and make
it oscillate slowly in a horizontal plane. Two larger leaden
spheres eight inches in diameter could be brought near the
ends of the beam, so that their gravitational attraction
on the spheres attached to the beam would displace it,
with the result that it would oscillate about the new posi-
tion of equilibrium. By bringing the larger spheres round
to the other side of the beam the displacement in the
opposite direction could be observed and the gravitational
effect measured. Cavendish fully realized the difficulties
he would have to encounter in consequence of almost
unavoidable air currents. Even when the apparatus was
enclosed in a box the slightest difference in temperature
would cause convection currents and, consequently, irre-
gular movements of the beam. He, therefore, had to plan
out a scheme which would allow him to conduct the whole
of the experiments without entering the room in which
the apparatus was placed. The observations were taken,
and the large leaden spheres moved one side of the beam
to the other from outside. No more delicate measurement
had ever been successfully carried out. From the average
of the number of observations, Cavendish deduced the
value of 5*48 for the density of the earth, a number in fair
agreement with, though slightly larger than, that obtained
by Maskelyne and Hutton. The extreme difficulty and
great charm of the experiment has still in our times
attracted the most skilled physicists, and the introduction
of quartz fibres by Mr. Vernon Boys has enabled us to
increase its accuracy considerably. The final value for the
average density of the earth as determined by Mr. Boys
is 5-5270, so that Cavendish was correct to within one per
cent.

John Michell (1724-1793), whose name has been mentioned
above as the inventor of that most useful and delicate
appliance, the torsion balance, has also in other directions
given evidence of great originality of mind. He contributed

88 Britain's Heritage of Science

an important paper entitled " Conjectures concerning the
cause and observations upon the phenomena of earthquakes "
to the Philosophical Transactions of the Royal Society,
and was the first to suggest that double stars were more
likely to be systems of physically connected bodies than
accidental coincidences in the directions of two stars which
might be at great distances one behind the other. This, as
will presently appear, was subsequently proved by William
Herschel to be the case.

It is not surprising that astronomy has always been a
favourite study of men of leisure, with a scientific turn of
mind. As Tyndall, in one of his lectures, said, we are most
impressed by what is either exceptionally large or excep-
tionally small; and the feeling that in examining the
heavens, our laboratory, no longer confined to a few cubic
feet, extends through the universe, fascinates the human
mind. Added to this, useful work can be carried on in
astronomy with comparatively simple though sometimes
expensive appliances, and to the painstaking, but not
perhaps, mathematically inclined enthusiast, special pro-
blems are often ready to hand, which depend on accurate
registration rather than on extensive knowledge. When,
as not infrequently happens, the power of dealing with
the observations is added to the aptitude for observation,
the amateur can rise to the level of the professional more
easily than in most other subjects.

It is impossible to say what position Jeremiah Horrocks
(1619-1641) might have attained had his life not been
cut short so early. He died at the age of twenty-two, with
a remarkable record to his credit. After passing through
Emmanuel College, Cambridge, as a sizar, he earned his
living as a teacher at his native place, Toxteth Park, near
Liverpool. Through William Crabtree, a wealthy draper
of Manchester, whose acquaintance he had made, he became
interested in astronomy, and on his advice studied the
works of Kepler. Having tested and corrected the tables
giving the positions of planets which had been published
by that astronomer, he formed the conclusion that a transit
of Venus would occur on the 24th November 1639. This
happened to be a Sunday, and Horrocks being at that

J. Horrocks, S. Molyneux 89

time a curate at Hoole was afraid that clerical duties would
prevent his observing the transit. He, therefore, asked
his friend Crabtree to watch independently for the appearance
of Venus on the solar disc. Fortunately, Horrocks was
set free before the planet had crossed the sun, and he
could follow its passage until the time of sunset. This was
the first time that human eye had witnessed this rare
occurrence. Among the frescoes by Madox Brown in
the Town Hall of Manchester one represents this transit
of Venus. Unfortunately, the pictures being intended to
commemorate events in the history of Manchester, the
scene is laid in that city, and Crabtree is made to be the
central figure, conveying a wrong impression of a great
historical event.

The papers left by Horrocks were preserved by Crabtree
and ultimately published. They show that he had the
making of a great man of science in him. Before he was
twenty, he showed how Kepler's laws had to be modified
in order to fit the motion of the moon, and he suspected
that these modifications were due to some disturbing cause
emanating from the sun, as Newton afterwards proved was
actually the case. He also discovered certain irregularities
in the motions of Jupiter and Saturn, now known to be due
to their mutual attractions.

The name of Molyneux first appears in this country at
the time of the Norman Conquest through William de
Moline, from whom the Earls of Sefton are descended.
Another family of the same name is derived from Sir Thomas
Molyneux, who came over from France, settled in Ireland,
and became Irish Chancellor of the Exchequer. One of
his great grandsons was Sir Thomas Molyneux, physician
and zoologist, another William Molyneux, a philosopher,
politician, and astronomer. Several of his papers were
published in the Transactions of the Royal Society. They
deal with the erecting eyepiece of terrestrial telescopes,
the tides and the causes of winds; he also pointed out
errors which occurred in surveying through neglecting to
take account of the secular variation of the magnetic
declination.

Samuel Molyneux (1689-1728), the son of William,

90 Britain's Heritage of Science

followed in his father's footsteps as astronomer, and built
himself an observatory at Kew. It was here that the
observations which led to the discovery by Bradley of the
aberration of light were carried out. Molyneux has not re-
ceived sufficient credit for the design of the instrument and
of the measuring appliances on which the successful prosecu-
tion of the research depended. The idea of testing Hooke's
method of measuring the so-called " parallax " of stars
seems to have been due to Molyneux. He worked assiduously
at the construction of telescopes, one of which he presented
to the King of Portugal, and left an unpublished MS. on
optics, which was made use of by Robert Smith in the
preparation of his treatise.

The work of William Herschel (1738-1822) brings us
into touch with modern astronomy. His father was a
musician in the Hanoverian Army, though the family
originally came from Moravia. At the age of fourteen he
accompanied, as an oboe player, a Hanoverian band on a
visit to England, but only settled finally in this country
in 1757, his health not being strong enough to take part
in the Seven Years' War. He ultimately went to live in
Bath as a teacher of music, and became director of the
musical entertainments in that fashionable resort. His
turn for reading serious books led him to the study of
Ferguson's astronomy and Smith's harmonics, followed by
the optics of the same writer. He then decided to take up
astronomy more seriously; he bought a small Gregorian
telescope, but not content with this, and, unable to obtain
a larger instrument with the means at his disposal, he set to
work with his own hands, and having succeeded in polishing
a mirror of six-foot focal length mounted it as a reflecting
telescope. A frequently quoted passage from one of his
letters, written in 1783, shows the object he had in view :
" I determined to accept nothing on faith, but to see
with my own eyes what others had seen before me. I
finally succeeded in completing a so-called Newtonian in-
strument, seven feet in length. From this, I advanced
to one of ten feet, and at last to one of twenty, for I had
fully made up my mind to carry on the improvement
of my telescopes as far as it could be done. When I

William Herschel 91

had carefully and thoroughly perfected the great instru-
ment in all its parts, I made systematic use of it in my
observations of the heavens, first forming a determi-
nation never to pass by any, the smallest, portion of
them without due investigation."

Even the largest of the instruments, mentioned in this
letter, did not satisfy him, and he determined to improve
upon it by constructing one of twice its size. This was
finally mounted at Slough, where he had settled with his
sister in 1782. The polishing of concave mirrors was at
that time a serious business. On one occasion he kept
the tool on the mirror continuously for sixteen hours, and
with both hands engaged had to be fed by his sister, Caro-
line, who then kept house for him. His desire to obtain
larger and larger instruments did not, however, prevent
Herschel from making good use of those he had completed.
Surveying systematically the whole of the heavens he was
soon rewarded by a brilliant discovery.

Struck by the peculiar appearance of a star that crossed
his field of view, he examined it with higher magnifying
powers, and found its apparent disc increased. Two days
later, a slight change of position could be detected. At
first it was thought to be a comet, but, ultimately, Saron,
at Paris, and Lexell, at Petrograd, found that its path in-
dicated an orbit round the sun of a nearly circular shape.
It then took its place as a new planet, the first that had
been discovered in historic times. The name " Georgium
Sidus," suggested by Herschel, was not generally accepted,
and was subsequently replaced by " Uranus." The dis-
covery was a fortunate one for Herschel, as it established
his reputation, and, what was more important, led
George III. to appoint him his private astronomer, with
a salary which, though modest, set him free to give up
his professional work and devote his entire energies to
astronomy. For a time, he increased his income by making
and selling telescope mirrors, but this ceased to be necessary
when, a few years later, he married a lady of independent
means.

The leading feature of Herschel's work was his strong
faith in the unity of design which he tried to trace in the

92 Britain's Heritage of Science

structure of the Universe. He looked upon the assemblage
of stars as an organic whole, and endeavoured to find
regularities in their distribution or arrangement. He thus
opened out an entirely new branch of enquiry.

If stars were scattered at random, we should find on
the average an equal number in all parts of the sky. In
order to avoid the enormous and practically impossible
labour of actually counting the total number of stars
visible in his telescope, Herschel devised a method of
gauging the heavens, which gave him sufficiently good
average results. This consists in taking specimens, by
counting the stars which appear in a number of single fields
of view near together, and taking the average number of
stars recorded as an index of the density in this particular
region of the heavens. It is obvious that the number of
stars is vastly greater in the Milky Way than anywhere
else, and the question arose whether that dense conglo-
meration had any relation to the rest of the stellar universe.
It was, therefore, a discovery of the greatest interest and
importance to find that the stars throughout the heavens
increase in density as we approach the region of the Milky
Way, thus demonstrating that the visible universe is not an
accidental jumble, but possesses an organized structure.

Results, of equal interest, were obtained from the close
investigations on double stars, of which about forty were
known when Herschel began his work. Having added
nearly 400 to this number, he set out to measure the relative
positions of the two components of each doublet, and,
repeating the measurements from time to time, discovered,
after twenty years of work, that some of these double stars
are physically connected, consisting of two huge and
luminous masses which revolve round each other.

The organic bond which connects the separate units of
the universe revealed itself in a striking manner, by Halley's
discovery already referred to, that many of the stars are
apparently moving through space with considerable velo-
cities. Examining the direction and magnitude of the
observed shifts, Herschel noticed that if the average motion
be taken in any one region, that average is nearly the
same in different parts of the sky. As our observations

William Herschel 93

can only indicate a motion relative to the earth, we must
conclude that if we consider the system of stars as a whole
to be at rest, our sun with its planetary system moves
towards a definite point in the heavens. If, on the other
hand, we consider the solar system to be at rest, then the
great majority of stars are drifting in nearly parallel
directions, and whatever view we may take it is certain that
the star velocities are not entirely independent of each
other. The subject is one that has received renewed
attention in recent years; it has now been demonstrated
that there is more than one star-drift, and Herschel's work
is likely to develop into an important -department of
astronomy.

One further discovery of considerable interest and im-
portance but belonging to the domain of physics, remains
to be noted. In order to compare the heating effects
of the coloured rays of which, as Newton taught us, solar
light is composed, Herschel placed thermometers in the
different portions of a spectrum obtained by means of a
prism. He noted that the heating powers of the rays
continuously increased from the blue through the green
and yellow to the red. He then discovered that the
thermometer rose highest when placed outside the red,
proving that the solar spectrum contains invisible rays less
refrangible than the red. These rays, though they do not
affect our eye, become apparent by means of then* heating
effect. Herschel satisfied himself that these invisible rays
were refracted and reflected according to the ordinary laws.

The idea of invisible radiations, refrangible like light at
the surface of transparent bodies was at that time entirely
novel, and must have appeared almost as surprising as the
discovery of Roentgen rays in our own time. The heat
radiations were at first looked upon with scepticism, and
met with opposition in some quarters, even when Wollaston
soon afterwards proved the existence of other rays beyond
the violet end of the spectrum which showed themselves by
their chemical effects.

The success of experimental investigation depends so
much on the use of scientific instruments and appliances
that the important share contributed to the progress of

94 Britain's Heritage of Science

science by the designers and makers of instruments deserves
to be emphasized. Improvements in the design of an instru-
ment lead not only to increased accuracy but also to the
saving of time and labour, which is frequently of equal
importance ; and in this connexion we need not necessarily
think of the construction of the costly instruments which the
astronomer now requires, nor of the elaborate appliances
to be found in a modern physical laboratory. The most
effective instrumental improvements have frequently been
of the simplest kind, and a handy appliance, such as the
slide rule, saves an amount of time which in the aggregate
may sum up to an astonishing figure. The slide rule was
introduced at a surprisingly early time. Almost immediately
following the introduction of logarithms, Gunter constructed
a rod with logarithmic divisions engraved on it, but its use
involved the application of a pair of dividers. The sliding
arrangement which is the essential feature of the appliance
was first used by Oughtred (1575-1660), a mathematically
inclined clergyman, who incidentally introduced the X sign
for multiplication and the symbol : : for proportion.

There is no department of science that depends on
instrumental appliances more than astronomy. The con-
struction of mirrors and lenses, the improvement of clocks
and the accurate angular division of measuring circles all
require skilled labour of the highest kind, while the require-
ments of navigation severely test the ingenuity of the
inventor, who has to simplify the instruments and make
their working independent of that firm support which may
be obtained on dry land, but is not available on board ship.

As an instrument of precision the telescope was almost
useless until some measuring arrangement was introduced.
A micrometer eyepiece consisting of two metallic edges,
the distance between which could be altered and measured
by a screw, was invented by a young astronomer, William
Gascoigne, a friend of Jeremiah Horrocks and Crabtree, born
about 1612, and killed in the battle of Marston Moor. The
Gascoignes are first mentioned in English history when Sir
William Gascoigne acted as Chief Justice in the reign of
Henry IV., and his son, George, acquired the reputation
of a poet, but it is not known whether the astronomer

W. Oughtred, J. Hadley, G. Graham 95

descended from them. Crabtree mentions the invention of
the micrometer in a letter to Horrocks, and the instrument
itself was exhibited by Townley at a meeting of the Royal
Society in 1667. Unfortunately it escaped the notice of
astronomers until Huygens had constructed a similar but
less perfect appliance, and Adrien Angout had produced a
micrometer in which Gascoigne's edges were replaced by
silk fibres.

If one had to select the instrument which combines the
greatest simplicity with the highest precision, there is little
doubt that one's choice would fall on the sextant, the most
perfect appliance that has ever been invented. It is mainly
used on board ship, but it has been successfully employed
in the United States for accurate surveys on land. No one
who has not held a sextant in his hand, and seen how, after
a few days' practice, he could determine the local time to
the tenth part of a second, and the latitude to a few hundred
yards, can realize the beauty of the instrument and the sense
of power it gives to its user. The inventor, John Hadley,
was an instrument maker about whose life very little is
known, though the Royal Society recognized his merits by
electing him to their Fellowship, and ultimately made him
a Vice -President. His instrument, the circle of which only
covered 45°, and which therefore ought more properly to ba
called an " octant," was first shown to the Royal Society
in 1744. Hadley also revived the use of reflecting telescopes ;
the construction of which had shown little progress since
Newton's time.

The accuracy of astronomical observations depends in
many cases on the excellence of the timekeepers employed
to record the instant at which a star passes the centre of
the telescopic field of view. Clocks used for the purpose
are regulated by the swing of a pendulum acting through a
mechanism called an escapement. The first efficient appli-
ance of its kind, the anchor escapement, was invented by
Robert Hooke, and improved upon by George Graham
(1675-1751), an ingenious clockmaker who was generally
interested in scientific matters. We owe to him, e.g., the
discovery of the diurnal variation of terrestrial magnetism.
In the construction of clocks he introduced an important

96 Britain's Heritage of Science

improvement. Owing to the expansion and contraction of
ordinary materials when the temperature rises or falls, the
time of oscillation of an ordinary pendulum alters with every
change of temperature ; but by properly combining different
materials, the difficulty may be overcome. Graham attached
a cylindrical vessel partly filled with mercury to the bob of
the pendulum; when the rod of the pendulum expands the
support of the mercury vessel descends, but the mercury
in the vessel also expands, which tends to raise the centre
of gravity of the whole arrangement. The expansion of
the mercury being considerably greater than that of the
pendulum rod, its volume may be adjusted so that the two
actions counterbalance each other, and the pendulum may
be made independent of moderate changes of temperature.
Another arrangement, the " gridiron " pendulum, was intro-
duced by John Harrison (1693-1776), the son of a York-
shire carpenter, who became a surveyor, and settled down
in London as a watchmaker. His pendulum compensation
has been very extensively used, but Harrison will chiefly
be remembered as the inventor of the chronometer.

The demand for accurate timekeepers suitable for use on
board ship had become so urgent a question at the time, that
the Government had offered a reward of £20,000 to anyone
who would produce an instrument which satisfied certain
requirements. Harrison soon supplied a te time-measurer "
or " chronometer " which promised so well that the Govern-
ment helped him with grants of money and facilities for
testing his instrument on sea journeys. But it took him
twenty-six years of continued labour before he obtained the
full reward, producing a chronometer which, on a journey
to Jamaica and back, showed an accumulated error of less
than two minutes; this satisfied the required conditions,
and the prize was awarded to him. One of the features of
Harrison's chronometer, showing great ingenuity and manipu-
lative skill, consisted in the temperature compensation which
was applied to the balance wheel.

Next to accurately going clocks, the astronomer requires
well-divided circles for the measurement of angles. Three
English instrument makers secured considerable reputation
in this work during the eighteenth century. The first of

John Harrison, Jesse Ramsden 97

these, Graham, whose name has already been mentioned in
connexion with clocks, worked for Halley and Bradley at
Greenwich, and supplied an instrument to the Paris Academy
of Sciences. The second, John Bird (1709-1776), divided
a number of quadrants for several public observatories, and
his method of working was considered so good that the
Government purchased the right of employing it.

Further improvements were introduced by Jes^e Ramsden
(1735-1800), the son-in-law of John Dollond, who designed
an engine for dividing mathematical instruments and re-
ceived a premium for £315 from the Government for this
invention. Ramsden was a remarkable man. The son
of an innkeeper at Halifax, he became a clerk in a cloth-
maker's warehouse, after having completed a three years'
apprenticeship. Two years later, when twenty-three years
old, he again apprenticed himself, this time with a mathe-
matical instrument maker, and afterwards established him-
self independently. His shop, first opened in 1762, in the
Haymarket, was transferred later to Piccadilly. He soon
acquired fame for the excellence of his workmanship, and
we are told that, though ultimately sixty workmen were
employed by him, the demand from all parts of Europe for
his instruments was greater than could be satisfied. He
was highly successful in constructing a new equatorial
mounting for telescopes and a clockwork which drove the
mirror of a siderostat so accurately that a star could be
followed for twelve hours ; but it was his skill in dividing circles
to which he mainly owed his great reputation. There can
be no doubt that his practice of substituting entire circles
for the usual quadrants and sectors was sound in principle
and contributed much to his success. Every student of
optics knows " Ramsden's eyepiece," and he also invented
a double image micrometer. The Royal Society recognized
his work by awarding him the Copley medal in 1795.

While clocks and divided circles are necessary parts of
an astronomer's equipment, he depends primarily on the
optical performance of his telescopes. Newton had used
mirrors to focus the beams of light, as he considered it
to be impossible to do so accurately by means of lenses,
because rays of different colours, being refracted to a different

98 Britain's Heritage of Science

degree in their passage through a lens, come to a focus at
different points. Hence the images formed by simple lenses
of glass are coloured. Though the possibility of combining
several lenses made of different materials had occurred to
Newton, he had come to the conclusion that the dispersive
power of substances (which is the power to separate different
colours), is proportional to their refractive power, and if
this were really the case, it would indeed be impossible to
construct a lens which could bring different coloured rays
to the same focus. The succeeding history of the subject is
interesting. Euler asserted that notwithstanding Newton's
experiments, which he accepted, it should be possible to
produce achromatism, i.e., images without coloration, by
means of a combination of lenses. David Gregory had
already in 1695 expressed similar ideas, and their argument
depended on the belief that the images formed by the human
eye are not deteriorated by any colour-dispersion. As the
rays entering the eye are concentrated on the retina by
successive refraction through different media, such as the
cornea, the crystalline lens and the vitreous humour, it
was argued that it should be possible to produce achromatic
images by properly combining lenses of different materials.
Euler's belief that the optical arrangement of the eye pointed
the way to the construction of achromatic lenses was shared
by others, and ultimately led to the solution of the problem ;
but the curious point is, that the premise on which the whole
argument depends is wrong, the eye not being achromatic
at all, but subject to the same defects as a simple lens.

A Swedish mathematician, Klingenstjerna, seems to have
been the first to repeat Newton's experiments with sufficient
care, when it appeared that the relationship between
refractive and dispersive powers, which Newton thought
he had established, did not hold accurately. John Dollond
(1706-1761), a son of one of the many French refugees who
came to England after the revocation of the Edict of Nantes,
had started life as a silk weaver in Spitalfields, but relin-
quished this occupation and established a workshop for
optical instruments. Having heard of Klingenstjerna's obser-
vation, he entered into an independent investigation on the
optical properties of different kinds of glass, and had the

John Dollond, Edward Somerset 99

satisfaction of solving, at last, this most important problem.
By combining two lenses of different kinds of glass, he could
produce images in which the colour defect was, though not
entirely abolished, yet very materially diminished. In this
discovery he was, however, anticipated by Chester More
Hall of More Hall in Essex, a barrister, who, in 1833, had
already succeeded in constructing an achromatic lens.
Dollond's patent was subsequently challenged on the ground
of anticipation, but the judgment was upheld in favour of
Dollond on the ground — containing much common sense —
that " it was not the person who locked his invention in his
scrutoire that ought to profit from such invention, but he
who brought it forth for the benefit of mankind."

The improvements effected in electrical appliances by
Canton, Henley, Bennett and others have already been
described, and we may therefore pass on to the more direct
applications of scientific principles to the utilization of power.
The early steam engines — we should hardly call them by
that name now — were little more than toys, useful, perhaps,
for the special purpose for which they were designed, but
wasteful and costly in their working. It was only when
James Watt came to apply the scientific methods acquired
in his intercourse with Joseph Black and John Robison
that an efficient machine could be evolved.

We may begin our account of the history of steam
engines with Edward Somerset, Marquis of Worcester,
whose romantic personality and tragic history form an
interesting study. He claims to have accomplished some
wonderful things in a publication that bears the eccentric
title : "A century of the names and skantlings of such
inventions as at present I can call to mind to have tried
and perfected, which, my former notes being lost, I have
at the instance of a powerful friend endeavoured, now in
the year 1655, to set down in such a way as may sufficiently
instruct me to put any of them in practice." But his
descriptions are so fantastic and vague that doubts have
been raised whether he had ever gone beyond the forming
of plans and making of projects, leaving the rest to his
imagination, which had ample scope to exercise itself
during a six years' confinement in the Tower of London.

G 2

100 Britain's Heritage of Science

We possess, however, the testimony of an eye-witness who
had seen near Vauxhall one of Worcester's machines raise
water through a height of forty feet. Engines were chiefly
wanted at the time for the pumping of water, more
especially to clear the mines, and it is therefore, not sur-
prising that the first practical application of the pressure
provided by steam should have been made by a miner.
Thomas Savery's (1650?-1702) machine probably resembled
that of Worcester, and it is immaterial whether it was
an independent invention or not. A short description may
serve to illustrate its mode of work. A cylindrical vessel
has three tubes leading out of it, each capable o; being
opened and closed by a stopcock. The first tube joining
the upper end of the cylinder is connected with a boiler;
the second (the inlet tube) leads from the bottom of the
cylinder vertically downwards to a reservoir of water, and
the third (the out'et tube), also connected to the bottom of
the cylinder, is bent round so as to lead vertically upwards.
To start the machine, the cylinder is filled with water, and
the stopcock of the inlet tube closed, while the two others
are opened. Steam is then admitted, and the water expelled
through the outlet tube. When the whole cylinder is filled
with steam the boiler and outlet tubes are closed, and the
inlet tube opened. The cylinder is cooled and the vacuum
formed by the condensation of the steam draws a supply
of water from the reservoir upwards into the cylinder.
When the cylinder is filled, the stopcock of the inlet tube
is closed, and the process repeated. The height to which
the water may be raised in this manner depends on the
pressure of steam employed, which in Savery's engine
reached up to eight or ten atmospheres, corresponding to
a height of about 250 feet of water. It will be seen that this
machine contains no piston such as we associate now with
steam engines, and there is no mechanical transmission of
motion. Its sole object is the raising of a weight of water
by the pressure of steam.

Papin (1647-1714), a French Calvinist who had to leave
his country on account of his religious opinions, lived in
England for some time, but ultimately accepted a pro-
fessorship in a German University. He suggested the use of

T. Savery, D. Papin,'T. N^wconien'- ^

a piston, but abandoned the idea in favour of a modified
form of Savery's engine.

During his stay in England, Papin took an active part
in the Proceedings of the Royal Society, and in 1684 was
appointed temporary curator of that body with a salary
of £30, in consideration of which he was required to pro-
duce an experiment at each meeting of the Society. He
had invented a so-called " bone-digester," to which Evelyn
in his diary refers in these terms : " The hardest bones of
beef itself and mutton were made as soft as cheese, without
water or other liquor, and with less than eight ounces of
coal, producing an incredible quantity of gravy; and, for
close of all, a jelly made of the bones of beef, the best for
clearness and good relish, and the most delicious that I
have ever seen or tasted." Papin kept up his correspondence
with the Royal Society after settling in Germany, sub-
mitting to them a proposal to apply a steam engine to the
propulsion of ships, and asking for a grant of £15 for his
" expense, time and pain " in putting his ideas to the test.
Papin is also credited with the invention of the safety
vaive.

The next successful step in the construction of steam
engines was taken by Thomas Newcomen (1663-1729), an
ironmonger of Dartmouth, who seems to have entered into
correspondence on the subject with Robert Hooke, and,
together with Cawley, another tradesman of his native
town, produced a machine which in several ways was better
than its predecessors. He introduced a cylinder with a
piston that could be raised by the pressure of steam, the
piston rod being mechanically connected with a pumping
arrangement. The steam was condensed in the cylinder
itself by a jet of water, and the work was mainly performed
in the downward stroke, when the atmospheric pressure of
air pressed the piston down into the vacuum formed inside
by the condensation of steam. Newcomen's engines came
into general use for the pumping of water.

In all the attempts made so far, no consideration is given
to the economical use of fuel, a disadvantage which was
severely complained of by those who used the engines.
A new era began with the work of James Watt (1736-1819

102- Britain' 3 Heritage of Science

We are all familiar with the story which tells how as a boy
he watched the steam escaping from a tea-kettle, and dreamt
of the future of steam-power. Such tales about precocious
signs of future greatness may have a psychological interest
when they are well authenticated, and given in the correct
perspective of surrounding circumstances ; but even then
we should not be able to estimate their true value unless
we knew how many boys watched tea-kettles and made
acute remarks without growing up to be great men.
When we are told, for instance, of another eminent man
who as a boy was asked to see what time it was, and returning
after looking at the clock, said : "I can't tell you what
time it is now, but when I looked at the clock it was ten
minutes past three," we are tempted to ask what proportion
of the boys who could give such an answer became great
mathematicians, and how many merely great prigs. The
story of Watt's tea-kettle rests on a memorandum dictated
by an oldiady, a cousin of his, fifty years after the occurrence,
but the most significant part of her account is not generally
mentioned. It was not the power of steam that Watt was
watching, but the condensation into water when the steam
came into contact with a silver spoon. The incident may
be accepted as a sign of a scientific and enquiring mind,
perhaps as a token of his interest in the properties of steam,
but not as a forecast of his future belief in the powers
of steam. James Watt came from a family of mathe-
maticians. His grandfather, Thomas Watt, was a teacher
of navigation, and his tombstone bears the title : " Pro-
fessor of Mathematics." His father was a shipwright,
supplying vessels with nautical instruments, and a mechanic.
In the latter capacity he made and erected, for the use of
Virginia tobacco ships, the first crane ever seen at Greenock.
Growing up in these surroundings, Watt at an early age
became familiar with the use of tools, and set up a small
forge for himself for the making and repairing of instru-
ments. He left his Scotch home and became apprenticed
to an instrument maker in London, but bad health obliged
him to return at the end of the year. When his attempt
to set up a shop at Glasgow was objected to by the guilds,
because he had not served his full apprenticeship, the

James Watt 103

difficulty was overcome by some of the professors who
had recognized his ability before he went to London, and
established him as instrument maker to the University.
This gave Watt the opportunity of entering into intimate
scientific intercourse with such men as Joseph Black and
John Robison, and gaining a knowledge of the scientific
principles of heat.

It was only in 1764, when a working model of one of
Newcomen's engines was sent to Watt for repair that his
mind was directed to the potential value of these machines.
Watt at once recognized the cause of the enormous waste
of fuel which constituted the chief defect of the engine.
When the steam introduced into the cylinder had done its
work by raising the piston, it had to be condensed before
the piston could return; this was done by a jet of cold
water introduced into the cylinder, which, of course, did
not only condense the steam but also cooled down the mass
of metal which formed the walls of the cylinder. When
the steam was reintroduced, the whole had to be raised up
again to the temperature of the steam before the piston
could be lifted. In order to avoid this waste of heat Watt
saw that the cylinder ought to be maintained permanently
at the temperature of the steam, and for this purpose it
became necessary to condense it, not in the cylinder itself,
but in another vessel, into which it had to be driven after
it had done its work. The invention of this separate con-
denser was Watt's first contribution to the steam engine.
He settled down in Birmingham with Matthew Boulton,
a capitalist, and gained experience in the manufacture of
his improved machines, which were still used exclusively
for pumping water.

The next great step was made in 1782. Up to that date
steam was only admitted to the cylinder on one side of the
piston, the return stroke being made by the pressure of the
air against the vacuum formed by the condensation of steam.
Watt now invented the double-acting engine, in which
steam is alternately admitted and acts on both sides of the
piston. The third advance, which brings us still nearer to the
modern engine, is due mainly to the scientific knowledge
which Watt had gained of the properties of steam, investi

104 Britain's Heritage of Science

gating for. himself the connexion between its temperature,
density, and pressure. Instead of allowing the steam to
pass into the cylinder during the whole of the stroke, Watt
saw that a considerable economy could be effected by
stopping the admission when the stroke had reached a
certain point and allowing the pressure of the steam already
in the cylinder to complete it. It is not necessary to enter
further into the many improvements of detail which the
steam engine owes to Watt, who, realizing the future that
was before it, also devised various means by which the up
and down stroke of the engine could be converted into
rotatory motion.

Savery is said to have been the first to suggest that the
measured power of performance of an engine might be in
terms of horse-power, but Watt actually investigated the work
that a horse could do in a given time, and defined one horse-
power as the rate at which work is done when 33,000 Ibs.
are raised one foot in one minute.

Watt was of a retiring disposition, due, no doubt, to
the weakness of health which, in the early part of his life,
greatly interfered with his work. He speaks of himself as
" indolent " and " not enterprising," and as being " out
of my sphere when I have anything to do with mankind."
His inventions were not confined to the steam engine. He
constructed a press for copying manuscripts, such as is now
in common use. It is also claimed on behalf of Watt,
and with some justification, that he was the first to discover
the true composition of water as a compound of oxygen
and hydrogen. The controversy which arose has already
been referred to (page 85).

The condenser used by Watt can be easily attached to
stationary engines, but is inconvenient when an economy
of space is imperative, as when steam is used for road
propulsion. The condenser may then be dispensed with,
but the pressure of steam has to be increased. Richard
Trevithick (1771-1833), whose father was the manager of a
Cornish mine, invented a road locomotive with high pressure
steam, and conveyed passengers with it on Christmas Eve,
1801. Some sort of steam vehicle had, however, already
been built in France by Nicolas Cugnot as early as 1769,

Watt, Trevithick, Murdock, Bramah 105

and William Murdock (1754-1839) is reported to have con-
structed a carriage drawn by steam about 1786. Never-
theless, Trevithick was the first to build a locomotive in
the modern sense, and to use it on the lines of a horse-
tramway in Wales. Finally, the introduction of two
cylinders, the steam escaping from one being utilized to
increase the work by acting on a piston in the second, may
be mentioned as being the prototype of the present com-
pound engines. This innovation is due to Jonathan Carter
Hornblower (1753-1815), who. among other things, invented
a machine for sweeping chimneys by a blast of air. Patent
difficulties stood in the way of putting the idea of the double
cylinder into practice, but it was re-invented and used in
machinery set up in Cornish mines in 1804 by Arthur Woolf .

The name of Murdock recalls that he was the first to
make a practical use of coal gas as an illuminating agent.
His father was a Scotch millwright ; he entered the employ-
ment of Boulton and Watt at the Soho Factory, Birming-
ham, in 1777, and a few years later was sent to Cornwall to
superintend the fitting of water engines in mines. He esta-
blished himself at Redruth, and is credited with several
inventions; there is a tradition that he created a sensa-
tion among the inhabitants by carrying, to and from the mine,
a lantern lit by gas supplied from a bag concealed under his
coat. After his return to Birmingham in 1799, he improved
his methods for making and storing the gas so much that
the exterior of the Soho Factory, and soon after the whole
of the interior, was lighted with the new illuminant.

During the last few years of the eighteenth century,
another great step forward in the transmission of power
was made when James Bramah (1749-1814) laid the founda-
tion of a new branch of engineering by the invention of his
hydraulic press. Bramah was the son of a Yorkshire
farmer. Being incapacitated for agricultural labour on
account of an accident, he started business as a cabinet-
maker in London, and made a number of inventions, such
as the lock which is known by his name. He suggested
improvements in the steam engine, foresaw the possibility of
propelling ships by screws, and advocated the hydraulic
transmission of power.

106 Britain's Heritage of Science

CHAPTER IV

(Physical Science)

THE HERITAGE OF THE NINETEENTH CENTURY

IN a superficial review of the history of science a new idea
or a striking experiment is associated with an individual
name and a particular date. Hence, we receive a general
impression that science proceeds by sudden inspirations ;
yet, on closer examination, we find that the salient features
are connected with each other, and that the great landmarks
are generally reached only by a succession of intermediate
steps, some of which may be as important as the last which
culminates in the final discovery. Time tends to efface the
intermediate steps, and so it happens that it is only in dealing
with the more recent events that we can obtain a correct
view of the continuity of science. To trace this continuity
is one of the functions of the historian, but occasionally
his efforts will fail, and he will be faced by what appears to
be an entirely new departure. Such was Volta's discovery
of current electricity, which surprised the scientific world
in the first year of the nineteenth century. The electrical
shocks which certain fishes can inflict on those who touch them,
and an accidental observation by Galvani, an Italian doctor,
disclosed a class of phenomena called " animal electricity."
But there was much confusion of ideas with regard to the signi-
ficance of the observed facts until Volta, the great Italian
experimenter, succeeded in separating what was physical
from what was physiological in Galvani's results, and so
laid the foundation of a new science. By discovering the
electrical effects that could be obtained at the contact of
two dissimilar metals, Volta was led to those wonderful
researches which gave us the electric battery, His previous

Anthony Carlisle, William Nicholson 107

work had earned for him the Fellowship of the Royal

Society in 1791, and desirous of showing his appreciation

of the honour, he not only contributed an important paper

to the Philosophical Transactions in 1793, but announced

his latest and greatest discovery in a letter addressed to

the President of the Royal Society, Sir Joseph Banks. That

letter bears the date March 20th, 1800, and appears to have

been sent in two parts, the second of which was delayed

in delivery, so that it could not be read before the meeting

of the Society, held on June 26th of the same year. In

the meantime, the first part of the letter had been privately

communicated to Sir Anthony Carlisle, the celebrated

surgeon of Westminster Hospital, and Professor of Anatomy

to the Royal Academy. Carlisle was mainly interested in

the physiological effects of electricity, and consulted William

Nicholson, a man of varied interests, who was employed

at different times as an official in the East India Company,

a traveller for the firm of Wedgwood, a school teacher and

a civil engineer. He had embarked on the publication of

a scientific periodical — Nicholson's Journal — and relates in

its fourth volume the important results he obtained by

experimenting with the battery constructed according to

Volta's directions. When two brass wires connected with

the electric poles were immersed in a tube containing water,

gas bubbles were seen to rise from one of the wires, while

the other became corroded. The gas proved to be hydrogen.

On replacing the brass wires by platinum, it was found that

oxygen was set free as well as hydrogen ; the electrolytic

decomposition of water was thus completely effected. This

was the first step in the brilliant series of experiments by

which English chemists and physicists traced the connexion

between chemical and electric action. But we must here

interrupt our account, and turn for a moment to another

subject.

The time had come when the correlation between the
various physical manifestations, such as light, heat and
power, forced itself into the foreground. The production of
heat by mechanical means was effected on a convincing scale
by Benjamin Thompson, better known as Count Rumford,
who had entered the service of Bavaria for the purpose of

108 Britain's Heritage of Science

organizing the manufacture of implements of war. His
previous experiments had convinced him that in accordance
with the views of Robert Hooke and other early physicists,
heat consisted in a motion of the ultimate particles of a body,
and as he controlled the machinery at Munich for making
guns, he had the opportunity of testing the matter. While a
cannon was being bored he filled the hollow already formed
with water, and found that it became hotter and hotter until
it boiled. The conclusion was obvious : heat could actually
be generated by mechanical power.

During an adventurous life Rumford rendered active
services to several countries. His family had settled in
Massachusetts, where he was born in 1753. At an early
age he showed mathematical tastes, but occupied himself
with abortive attempts to discover perpetual motion, and
with experiments on fireworks. After the outbreak of the
American war he entered a local regiment of militia on the
American side, where his position was rendered untenable by
the doubt which was cast on his loyalty to the caus^ of
freedom. He left the army and, when Boston was evacuated
in 1776, he came to England, where he was appointed to
a clerkship at the Colonial Office, rising rapidly within four
years to the position of Under Secretary of State. In the
meantime he carried on his scientific pursuits, and was
elected a Fellow of the Royai Society in 1779. He returned
for a time to Ameiica on active service, but resigned again
at the conclusion of the war, with the rank of Colonel. He
then determined to join the Austrian army, then engaged in
war with Turkey. While on the way to Vienna he was
introduced to Prince Maximilian, the future King of Bavaria,
and was persuaded to enter the government service of that
state. With the consent of King George III., who bestowed
the honour of knighthood upon him, he remained at Munich,
where he held consecutively the offices of Minister of War,
Minister o. Police, and Grand Chamberlain. In addition to
the improvements he effected in the Bavarian army, he
developed the industries of the country and did much to
mitigate he extreme poverty of a large part of the popula-
tion. His methods were strongly philanthropic. " To make
vicious and abandoned people happy," he said, " it has

Count Rumford, Sir Humphry Davy 109

generally been supposed necessary first to make them vir-
tuous. But why not reverse this order? Why not make
them first happy and then virtuous ? " He adopted the
name Rumford on being created a Count of the Holy Roman
Empire in 1791. Some years later he returned to England
and founded the Royal Institution, which received its charter
in 1800. His later years were spoilt by an unhappy attach-
ment he had formed to the widow of Lavoisier, the great
French chemist, who had suffered death on the guillotine
during the Revolution. Their marriage took place in 1804,
but resulted in an uncomfortable life for several years, until
a separation was agreed upon. He died in France in the
sixty-second year of his age.

Rumford probably rendered his greatest service to
science when, in 1801, he selected Humphry Davy for
appointment as first lecturer on Chemistry and Director of
the Laboratory at the Royal Institution. Davy (1778-1828)
had already shown his intense enthusiasm for research,
though his first attempts at original work were remarkable
for great power of scientific imagination, rather than for
sobriety of judgment. A trial lecture at which Rumford
was present, settled, however, the question of his appoint-
ment.

" I consider it fortunate that I was left much to
myself when a child, and put upon no particular plan of
study, and that I enjoyed much idleness at Mr. Coryton's
school. I, perhaps, owe to these circumstances the little
talents that I have and their peculiar application."
These words of Davy's, written to his mother at a later
date, show that Davy did not establish any reputation
for studiousness as a boy ; but his literary gifts must have
appeared at an early age, for we are told that the love-
sick youths of Penzance employed him to write their
valentines and letters.1 Davy's father had died in poor
circumstances, and the mother established a milliner's shop
in Penzance to provide the means of educating her younger
children. Humphry, the eldest of them, had then already

1 The account of Davy's life and work is almost entirely derived
from Sir Edward Thorpe's most excellent and interesting little volume,
" Humphry Davy — Poet and Philosopher " (Century Science Series).

110 Britain's Heritage of Science

spent four years at the Grammar School at Penzance, and
one at Truro. At his father's death he realized the necessity
of setting to work seriously, and was apprenticed with an
apothecary and surgeon practising in Penzance. He then
began a course of extensive reading covering nearly all
branches of learning. Metaphysics seems to have more
especially attracted his attention, and he wrote a number of
essays on such subjects as " The Immortality and Imma-
teriality of the Soul," " Governments," and " The Credulity
of Mortals." Some of his aphorisms indicate great originality
of thought, and one almost hears the voice of Poincare in the
passage in which he declares that : " Science or knowledge is
the association of a number of ideas, with some idea or
term capable of recalling them to the mind in a certain
order." Turning his attention to experimental research, Davy
at this period studied Lavoisier's " Elements of Chemistry,"
and formed original, but not very happy, ideas on the
nature of light, which he communicated to a medical man,
Dr. Thomas Beddoes, with important results on his future
life. Dr. Beddoes had a notion that the study of the
physiological effects of different gases might have important
therapeutical applications. With this purpose in view, he
founded the " Pneumatic Institution " at Bristol, and,
impressed by Humphry Davy's work, he put him in charge
of the laboratory. The experiments on gases led to results
of importance. While examining the properties of nitrou
oxide, Davy observed those remarkable physiological pro-
perties which give to this gas its familiar name of " laughing
gas." Mary Edgeworth, a sister of Mrs. Beddoes, thus
describes the discovery :

" A young man, a Mr. Davy, at Dr. Beddoes', who
has applied himself much to chemistry, has made some
discoveries of importance, and enthusiastically expects
wonders will be performed by the use of certain gases,
which inebriate in the most delightful manner, having
the oblivious effects of Lethe, and at the same time
giving the rapturous sensations of the Nectar of the
Gods ! Pleasure even to madness is the consequence of
this draught. But faith, great faith, is,r I believe,
necessary to produce any effect upon the drinkers, and

Sir Humphry Davy 111

I have seen some of the adventurous philosophers who
sought in vain for satisfaction in the bag of ' Gaseous
Oxyd,' and found nothing but a sick stomach and a
giddy head."

As a result of further experiments with nitrous oxide,
Davy mentions its power of destroying physical pain and
suggests its application in surgical operations; but no
notice of this suggestion was taken for half a century.
Davy's researches on gases were preceded by the unhappy
publication already referred to — " On Heat, Light, and the
Combinations of Light, with a new Theory of Respiration,"
in which he tries to demolish Lavoisier's theory that oxygen
was a compound of an elementary substance and " heat."
The paper is in great part of a speculative nature, and full
of hasty and ill-considered opinions. He was, no doubt,
right in his contention that heat is not a substance, but he
spoils his case by adhering to the belief in the compound
nature of oxygen, replacing only Lavoisier's " heat " by
the equally imaginary substance " light." He tries to prove
by experiments which are not to the point that light is not
due to the vibrationary motion of an elastic medium, and
even states that oxygen cannot be produced from oxide of
lead by heating it in the dark. A statement of this kind
renders it doubtful whether he was sufficiently careful in
excluding all possible sources of error in another experiment,
described in the same paper, in which two pieces of ice
were melted in an exhausted receiver by rubbing them
together.

The errors of a self-trained, impulsive young man would
hardly be worth recording were it not for the chastening
effect which the severe criticisms they evoked had on his
subsequent work. Davy never forgot his lesson; he
remained impulsive, but became much more careful in his
experiments, and avoided speculative theories like a child
avoids fire when it has burnt its fingers. Within a year he
published a letter in Nicholson's Journal, in which he says :
" I beg to be considered as a sceptic with regard to my
particular theory of the combinations of light, and theories
of light generally." Before we leave Davy's activities at
Bristol, we may quote a passage from one of his letters

112 Britain's Heritage of Science

which illustrates his wonderful powers of intuition in hitting
on the essential points of an experiment :

" Galvanism " (we should now call it " current
electricity ") "I have found, by numerous experiments,
to be a process purely chemical, and to depend wholly
on the oxidation of metallic surfaces, having different
degrees of electric conducting power.

" Zinc is incapable of decomposing pure water ; and if
the zinc plates be kept moist with pure water, the galvanic
pile does not act; but zinc is capable of oxidating itself
when placed in contact with water holding in solution
either oxygen, atmospheric air, or nitrous or muriated
acid, etc., and under such circumstances the galvanic
phenomena are produced, and their intensity is in pro-
portion to the rapidity with which the zinc is oxidated."
Davy took up his position as Assistant Lecturer at the
Royal Institution in London, and so brilliantly did he
discharge his duties that his audience was taken by storm,
and the lecture room was soon filled with enthusiastic
listeners. The full title of lecturer was given him at
once, and the Philosophical Magazine predicted that " from
the sparkling intelligence of his eye, his animated manner,
and the ' tout ensemble,' we have no doubt of his attaining
a distinguished eminence." The control of the subjects to
be investigated rested at the time with the governing body,
and the Institution having been founded with a view to the
practical applications of science, the managers resolved that
Davy should give a course of lectures on the Principles of
the Art of Tanning; he received leave of absence during
three summer months for the purpose of making himself
acquainted with the subject. Subsequently he was requested
to devote his energies to agriculture, and the various duties
which the authorities of the Royal Institution imposed
upon him took up much time which would have been better
employed in research work. Nevertheless, he found sufficient
leisure to return to his favourite study, the chemical action
of electric currents, with the result that in 1806 he commu-
nicated a paper to the Royal Society which was made the
Bakerian lecture of the year. It constitutes a most impor-
tant contribution to science, and lays the foundation — in

Sir Humphry Davy

From a painting by Sir Thomas
Lawrence, in the possession of the
Royal Society

Sir Humphry Davy 113

some respects more than the foundation — of our present
science of electro-chemistry. The sensation which the paper
created in England was great; its effect abroad may be
judged from the fact that the French Academy recommended
Davy as first recipient of the gold medal, promised by
Napoleon for " the best experiment that should be made
in each year on the galvanic fluid." This recognition had a
special value, owing to its being bestowed in the face of a
bitter political hostility between France and England, then
at war with each other.

Davy continued his researches and in the following year
was already able to announce another discovery of funda-
mental importance which forms the subject of his second
Bakerian lecture. The construction of electric batteries had
been materially improved by Cruikshank, a surgeon, and
Davy had modelled his own apparatus on Cruikshank's
pattern. The metals used were copper and zinc, and two
of the batteries consisted of 50 and 100 cells respectively,
the plates in the first measuring six, and in the second,
four square inches. With the two batteries in series, Davy
made a determined attempt to decompose the so-called
fixed alkalis : soda and potash. When a current is passed
through the aqueous solution of these bodies, only hydrogen
and oxygen are set free at the poles. Other experimental
methods had, therefore, to be tried. As potash at ordinary
temperatures does not conduct the current sufficiently well
to show any effect, it was raised to a temperature at which
it fused, and the current then produced a highly inflammable
substance, which burst into flame by contact with air. In
order to isolate that substance, Davy saw that it was
necessary to conduct the experiment at ordinary tempera-
tures, and succeeded in doing so by utilizing the hygroscopic
properties of the substance, which, on exposure to damp
air, cause it to become covered with moisture. The current
then passed through the highly-concentrated liquid surface
layer. With his 150 cells Davy found the electrical effect he
looked for, and was able to isolate metallic potassium. He
announced his discovery in these words :

" Under these circumstances a vivid action was soon

observed to take place. The potash began to fuse at

H

114 Britain's Heritage of Science

both its points of electrization. There was a vio ent
effervescence at the upper surface; at the lower, or
negative surface, there was no liberation of electric
fluid; but small globules having a high metallic lustre,
and being precisely similar in visible characters to quick-
silver, appeared, some of which burnt with explosion
and bright flame, as soon as they were formed, and others
remained, and were merely tarnished, and finally covered
by a white film which formed on then- surfaces."
Sodium was similarly obtained from soda.
The interest which the announcement of the discovery
of two new elements created throughout the scientific world
was accentuated by the peculiar properties which distin-
guished them from all known metals. They are both lighter
than water, and when brought into contact with that liquid
burst into flame, owing to their great affinity for oxygen.
The investigation of their chemical properties was most
difficult, because they oxidize rapidly when exposed to air,
and can only be preserved by being immersed in naphtha
or some similar liquid. Though a serious illness interrupted
Davy's work, he continued to give the Bakerian lecture
for six successive years, each time adding something to
our knowledge, mainly in connexion with the researches
which have already been described. He received the honour
of knighthood in 1812, and shortly afterwards informed the
managers of the Royal Institution that he could not pledge
himself to continue his lectures, but was prepared to retain
his position as Professor of Chemistry and Director of the
Laboratory without salary. This offer was accepted. In
the same year he published his " Elements of Chemical
Philosophy," in which he described the " Voltaic Arc," that
column of light which is formed between carbon points when
a current of sufficient electromotive force is passed between
them. Even Davy's vivid imagination could hardly have
foreseen the part which this discovery was to play in the
future history of illumination. The same paper contains
another important result. Partly anticipating the subsequent
work of Ohm, the electric resistance of a conductor was
shown to be proportional to its length directly, and inversely
to its cross -section.

Sir Humphry Davy 115

His connexion with the Royal Institution was finally
severed in 1813, and during the late autumn of that year he
set out — accompanied by his wife and Faraday — on what
he called a " journey of scientific enquiry." He was received
with great honour in Paris, where he attended the meetings
of the Academy of Science, which elected him a corre-
sponding member. On November 29th a paper was read
to the Academy on a new and remarkable substance dis-
covered by Courtois, which, when heated, gave out a violet-
coloured vapour. This was followed a week later by a
communication from Gay Lussac, pointing out its analogies
to chlorine and bromine, and proposing the name " iode "
for it. It is characteristic of the impetuous manner in which
Davy rushed through a research that, having obtained a
small quantity of the substance, he at once set to work, and
on December 20 a letter, in which he described his experi-
ments, was submitted to the Academy by Cuvier. After a
few days he forwarded his complete results to the Royal
Society, proposing the name of iodine as the English
equivalent for the new substance.1

Another example of Davy's activity during this journey
remains to be mentioned. At Florence he made use of the
great burning-glass belonging to the Accademia del Cimento,
by means of which it had already been shown in the reign
of Cosimo III. that a diamond is inflammable when the
rays of the sun are concentrated upon it. On repeating
the experiment Davy found that the products of combustion
consisted almost entirely of carbonic acid, and pronounced
diamond to be pure carbon. This result had an importance
greater than that which attaches to the record of a new
experimental fact; for it was the first well-established
instance of a chemical element existing in two different —
now called allotropic — forms.

Shortly after Davy's return to England in 1815, a Society
that had been formed to discover, if possible, some method
by which explosions of fire-damp could be prevented, asked

1 The French Academy began to publish its " Comptes Rendus "
only in 1835. For a reprint of the papers connected with the dis-
covery of iodine, the reader is referred to four communications in the
Annales de Chimie," vol. 87, pp. 304-329.

H 2

116 Britain's Heritage of Science

his assistance. These explosions claimed many victims,
and some remedy had become a pressing need. Davy
acceded to the request with enthusiasm, and offered at
once to visit some of the mines. The invention of the
miner's lamp, which, perhaps, has saved more human lives
than any other contrivance, was the result of Davy's efforts.
It is not necessary here to describe the principle on which
it is constructed, but it may be pointed out that the lamp
embodies a technical application of pure science, which no
one would have been able to devise without a thorough
knowledge of the principles of Physics and Chemistry,
together with a considerable experience in laboratory work.
The invention was at once appreciated by those whom it
was intended to benefit, and one can imagine the pleasure
with which Davy received the following letter signed by
eighty -three Whitehaven colliers :

" We, the undersigned, miners at the Whitehaven

Collieries, belonging to the Earl of Lonsdale, return our

sincere thanks to Sir Humphry Davy for his invaluable

discovery of the safe lamps, which are to us life-preservers ;

and being the only return in our power to make, we

most humbly offer this, our tribute of gratitude."

His services were recognized officially by the bestowal

of a baronetcy. Davy acted as Secretary of the Koyal

Society between 1807 and 1812; and was elected President

in 1820. His predecessor, Sir Joseph Banks, had before his

death expressed his preference for another Fellow, and

based his objection to Davy on the ground " that he was

rather too lively to fill the chair of the Royal Society."

Davy, however, was elected, and filled the chair to the time

of his death in 1827.

No account of Sir Humphry Davy's life would be com-
plete without reference to his poetic temperament and
literary talents. Coleridge said of him : "If Davy had not
been the first chemist, he would have been the first poet
of his age." By a vivid and impressive style of lecturing, he
attracted large audiences to the Royal Institution, which
soon became popular. It was a fortunate day for that
Institution when Davy was put in charge of the chemical
department, for serious financial difficulties were threatening

Sir Humphry Davy 117

its existence. The stress was at once relieved by the large
addition of new members attracted by the engaging per-
sonality of the young lecturer.

A significant light is shed on the small value then
attached by the English Universities to experimental science
by the fact that none of them ever publicly recognized
Davy's work. The only University honour he received was
the LL.D. degree from Trinity College, Dublin.

Yet a great revival of scientific activity had already
begun at Cambridge, though at the time of Davy's death
it was mainly confined to the domain of pure mathematics.
It is sad to think how a spirit of loyalty to its greatest
ornament should have paralysed that great University for
almost a century, by compelling a rigid adherence to the
details of Newton's formal procedure, for it was almost
purely a question of nomenclature that delayed progress.
In using the method of " fluxions," which is identical in
its fundamental ideas with what we now call the Differential
Calculus, Newton denoted the rate of change of a quantity,
say u, depending on another quantity, say t, simply by
placing a dot over the u. If u be the length of path travelled
over by a point, and t the time, u would represent the
velocity. Leibnitz, starting from the idea of infinitely small
quantities, placed a d before the symbol of the variable
quantity; dt would be an indefinitely small time, and dujdt
would represent the velocity. From the purely philosophic
point of view there is much to be said for Newton's notation,
but as an instrument of research, that introduced by Leib-
nitz had considerable advantages, more especially in the
inverse process of integration. When Cambridge began to
wake up, Charles Babbage (1792-1871) was among those
who helped to introduce the methods which had been so
successful in the hands of the great French mathematicians
of the eighteenth century. A special society — the Analy-
tical Society — having been formed for the purpose, Babbage
neatly expressed the objects of the society as " advocating
the principles of pure ' de-ism ' for the ' do£-age ' of the
University."

The founder of the new school was Robert Woodhouse
(1773-1827), Lucasian Professor of Mathematics between

118 Britain's Heritage of Science

1820 and 1822, and subsequently Plurnian Professor of
Astronomy. Already in his earliest work he strongly advo-
cated the continental system of notation, but little progress
was made at the time. His views began to prevail mainly
through the efforts of Babbage, combined with those of
two other Cambridge mathematicians, George Peacock and
John Frederick Herschel, the son of Sir William Herschel
the great ast onomer.

Charles Babbage is widely known in connexion with
an ambitious calculating machine which he proposed to
construct. His first machine was designed mainly for the
preparation of astronomical tables; his second was to
perform all kinds of arithmetical operations, but it never
emerged from the state of general design, and no detailed
drawings were made. His mathematical work, however,
was not without importance. He was generally active in
the cause of science. It was partly through his efforts that
the Royal Astronomical Society was founded, and he strongly
supported the British Association in its early days. It is
notewor hy that at the second of its meetings he strongly
urged that "attention should be paid to the object of
bringing theoretical science in contact with the practical
knowledge on which the wealth of the nations depends."

Babbage occupied for a time the Lucasian Chair . of
Mathematics, but spent the last years of his life in London.

George Peacock (1791-1858), another important member
of the new group, occupied for a time the Lowndean Chair
of Astronomy, which he resigned on his appointment to the
Deanery of Ely. He played an important part in the founda-
tion of the Cambridge Philosophical Society, and in the
early history of the British Association. For the latter body
he wrote an account of the progress of mathematical analysis,
the first of the important series of reports in different
branches which are published in its annual volumes.

Of John Herschel we shall have to speak in another
connexion; his name is introduced here because his earlier
work deals with mathematical analysis, and helped to
introduce the differential notation.

In their endeavours to reform the teaching of rnathe
matics Peacock and Herschel were assisted by William

Babbage, Peacock, Whewell 119

Whewell (1794-1866), whose name will chiefly be remem-
bered by his " History of the Inductive Sciences," a book
in three volumes published in 1837, and containing a large
quantity of useful information. Whewell ultimately became
Master of Trinity College, and gained great influence in the
University, but his attitude in later life became strongly
conservative and antagonistic to all proposed reforms.

A new branch of science — " Physical Optics " — emerged
from the work of Fresnel and Young, and when Arago and
Brewster had discovered the beautiful colour effects shown
by polarized light transmitted through plates cut out of
crystals, mathematicians had a good opportunity of applying
their talents to test the powers of the wave-theory. When,
as in Arago's experiments, the light sent through the plate
is confined to a parallel beam, the difficulties are compara-
tively slight, and were dealt with satisfactorily by the
French physicists. But a number of parallel beams sent
through the plate in all directions, and properly iocussed.
show more complicated and very beautiful effects, coloured
bands being crossed by light or dark brushes of various shapes.
The mathematical analysis then becomes more formidable,
especially when the crystals have — as in the case of quartz
— the peculiar property of turning the direction of the light
vibration. Among those who successfully attacked these
problems Airy held a distinguished place.

George Biddell Airy (1801-1892) had a brilliant Univer-
sity career. He entered the University at the age of eighteen,
and four years later graduated as Senior Wrangler, and
obtained the first Smith's prize. In 1826 he was elected to
the Lucasian Professorship, a position which Newton's name
has always invested with a certain glamour.

Though keenly interested in many branches of Physics,
Airy was more particularly attracted by astronomical pro-
blems, and when a vacancy in the Plumian Professorship
occurred in 1828, he became a candidate, and after election
took charge of the Cambridge Observatory, which had just
been established, mainly through the efforts of George
Peacock. The wide range of subjects enriched by Airy's
investigations may be illustrated by noting the titles of his
first six contributions to science. These were : "On the

120 Britain's Heritage of Science

figure of the earth " ; "On the use of silvered glass for the
mirrors of astronomical telescopes " ; " On the figure assumed
by a fluid whose particles are acted on by their mutual
attraction and small extraneous forces " ; " On the principles
and construction of the achromatic eye-pieces of telescopes,
and on the achromatism of microscopes " ; "On a peculiar
defect in the eye and a mode of correcting it " ; " On the
forms of the teeth of wheels." All these papers mark an
advance in their subject matter, and they were written
before Airy had reached the age of twenty-four.

His investigation on eye-pieces was considered to be of
sufficient importance for the Royal Society to vote him the
Copley Medal, their highest award, in 1831. The paper which
he wrote on a " peculiar defect of the eye " deals with
astigmatism. Airy, finding that he could not read with one
eye, investigated the cause, and observed that the defective
eye could not properly focus a point of light which was
drawn out into line. This suggested the method of correcting
the defect by employing a cylindrical lens. Airy was not
aware that Thomas Young had already previously described
the astigmatism of the eye. But Young had only met with
slight cases, and thought that an ordinary lens slightly
inclined was sufficient to correct the defect.

Airy's principal contribution to Physical Optics is con-
tained in a paper in which the coloured curves observed in
crystalline plates are mathematically explained and the
results more particularly applied to the beautiful spiral forms
seen in quartz under certain conditions. Another paper
deals with the rainbow, the general explanation of which was
first given by Descartes. Most people will have observed that
the violet of the rainbow is frequently followed by a dark red
and a succession of colours, sometimes twice repeated. The
cause of these so-called supernumerary rainbows was given in
a general way by Young, who showed that their appearance
depends on the interference of light which manifests itself
when the sizes of the raindrops are nearly equal ; but Airy
gave the first mathematical treatment of the subject.

Terrestrial Magnetism was another subject to which
Airy devoted his attention, more especially after he had
gone to Greenwich as Astronomer Royal. The connexion

G. Airy, J. Baden Powell, G. Green 121

of astronomy with the problems of navigation has always
been maintained at the Royal Observatory, and the intro-
duction of iron ships presented new problems, because the
ship became magnetic under the influence of the earth's
forces, and the compass needles were very seriously deflected
from the normal direction. An iron ship, The Rainbow,
having been placed at his disposal, Airy was able to deter-
mine the amount of the deviation experimentally, and
following up the observations by a mathematical investi-
gation, he showed how the effects could be compensated
by placing small permanent magnets near the compass.

In the work of spreading the new ideas on the nature of
light, useful help was given by J. Baden Powell (1796-1860),
the son of a gentleman who at one time was High Sheriff
of Kent. He graduated at Oxford, took holy orders, and
devoted himself to mathematical studies while holding
a living in Kent. In 1827 he was appointed Savilian Pro-
fessor of Geometry at Oxford, where he took an active part
in advocating University reform. Powell wrote a treatise
on experimental and mathematical Optics, investigated the
reflexion of light from metallic surfaces, and showed that
highly absorbing bodies in the crystalline state resembled
metals in some of their optical peculiarities. He also estab-
lished the commonly used empirical law connecting the
refractive 'ndices of rays of light with their wave-length.

Important as these results may be, they only dealt with
isolated problems, but did not touch fundamental principles.
The work of George Green (1793-1841) stands on a higher
level; indeed, had it become more generally known and
appreciated, it might rank as one of the landmarks of
science. Green, the son of a miller in Nottinghamshire,
entered the University of Cambridge when he was forty
years old, and had already written a most important
mathematical investigation, which was published by private
subscription. This paper dealt with electricity and mag-
netism, and it was only during the last few years of his life
that he published his investigations bearing on Optics.
This part of his work was introduced by a paper on Sound,
in which the subject is treated by powerful methods, now
familiar to every student of mathematical physics, but

122 Britain's Heritage of Science

then quite novel ; it marked a considerable step in the
philosophical treatment of the subject. As one result of this
investigation, the complete internal reflexion which occurs
when sound passes from one medium to another, possessing
different elastic properties, was demonstrated in opposition to
Cauchy, who had come to a contrary conclusion.

The subject of light is dealt with in a masterly manner
in two papers. The general properties of elastic media are,
for the first time, examined mathematically, and light is
treated as a special case of waves passing through a perfectly
elastic body. Green must be considered to be — after Newton
— the founder of the Cambridge school of Mathematical
Physics. He did not — like Cauchy and Franz Neumann —
discuss the causes which give bodies then* elastic properties,
and could, therefore, dispense with any hypothesis on the
mutual action of molecules, or on the ultimate constitution
of the luminiferous aether. All he needed was the assumption
that its properties were such as to comply with the principle
of the conservation of energy. That principle had not, at
that time, been formulated, but appears implicitly in Green's
work. The investigation solved, under certain suppositions,
the problem of the transmission, reflexion and refraction of
waves passing through homogeneous elastic bodies. The only
question that remained was, whether the observed laws of
light could be made to agree with the mathematical formulae
obtained. The two main experimental tests that could be
applied were the intensities of light reflected at the surface
of transparent bodies and the laws of double refraction.
The French physicist Fresnel had broken the ground, and
obtained satisfactory solutions for both problems, but his
analysis was not free from serious defects, and the hypothesis
he applied in one case was inconsistent with that introduced
in the other. The more rigid treatment of Green, together
with the subsequent investigations of Stokes, McCullagh and
Rayleigh, led to a deadlock, for no consistent hypothesis
could be framed to fit all cases. Fortunately Clerk Maxwell's
electrodynamic theory of light disposed of these difficulties.

Green's first paper on Electricity and Magnetism is
considered to be his most important contribution to science,
but being of a highly technical character, it must suffice to

George Green, George Stokes 123

point out that the use of a certain mathematical function
already introduced by Laplace was now employed to the
greatest advantage under the name " potential," a term which
has proved of such universal utility in all branches of physics,
owing to its nominal as well as real connexion with the
conception of " potential energy."

Here begins the golden age of mathematics and physics
at Cambridge. Its period is coincident with the scientific
activity of George Gabriel Stokes (1819-1903), which began
in 1842, and extended, with but slightly diminished vigour,
to the end of last century. Stokes' position as an investi-
gator is among the greatest, but his influence cannot be
measured merely by the record of his published work. He
united two generations of scientific workers by the love and
veneration centred in their gratitude for the assistance and
encouragement which, with kindly and genuine interest, he
showered upon them out of the wealth of his knowledge and
experience. Even those who intellectually were his equals
owed much to his sound and impartial judgment. Turning
away from the grave which was closing over his lifelong
friend, Kelvin was heard to say : " Stokes is gone, and I
shall never return to Cambridge."

Stokes' first papers dealt with fluid motion, a favourite
subject, to which he frequently returned. It is impossible
in an account intended to be intelligible to the non-
mathematical reader, to indicate even the general import
of his fundamental investigations in one of the most difficult
subjects of applied mathematics. The interest attaching to
the shape and propagation of waves will, however, be readily
understood, and the importance of questions of stability,
which enter so much into the recent advances of aero-
nautics, does not need emphasizing at the present time.
Both questions rest on that most careful consideration of
the fundamental principles of fluid motion, to which Stokes
applied his great critical powers.

The subject of light is, perhaps more than any branch
of physics, indebted to Stokes. The problems of the aberra-
tion of light and the phenomena of double refraction were
the first to attract his attention, and he recurs frequently to
the question of the constitution of the luminiferous aether.

124 Britain's Heritage of Science

He wrote from the point of view of the elastic solid theory
of light, which now is abandoned, but his papers, and more
especially that on the Dynamical Theory of Diffraction, have
lost none of their value.

Though a keen mathematician, Stokes was equally
interested in realities, and he has given us at least one
experimental discovery of primary importance. It was known
already to the Jesuit Kircher (1601-1680), and to Robert
Boyle, that extracts of certain woods presented a different
appearance when examined by transmitted or reflected light ;
John Herschel and David Brewster added some material
facts, and though they tried to theorize on them, they did
not make much headway in fitting the facts into the general
framework of Optics. Stokes attacked the problem in the
true Newtonian manner. Sunlight admitted through a slit
in a shutter entered the room, and, after passing through
three prisms, was made to form a spectrum on a screen.
Solutions of the substances to be examined, such as sulphate
of quinine or esculine, were placed in a test tube, and then
passed along the screen, so that they were successively
illuminated by the different colours of the spectrum. In the
red, yellow, green and blue, the substances behaved much
like transparent liquids, but when placed in violet they
began to shine, emitting a strong blue light, and this was
accentuated when the test tube was moved beyond the visible
spectrum, into what we now call the ultra-violet. The
existence of such rays had already been proved by means of
their chemical action, but Stokes widened their range to a
quite unexpected degree by using prisms made of quartz,
instead of glass; for the glass, as he showed, strongly
absorbed those rays. The practical application of these
researches, extending optical investigations into the regions
of waves which are too short to affect our eyes, became
apparent after the introduction of spectrum analysis, and
Stokes himself, in a subsequent research, investigated the
ultra-violet spectra of metals. But at the time, the novel
result emerging from the work was the discovery that the
substances experimented upon had the power of changing
the wave-length of the light which fell upon them. This was
quite contrary to what Newton had taught. Newton was

m

Sir George Gabriel Stokes

From a photograph by
Fradelle & Young

G. G. Stokes, J. C. Adams 125

right, of course, with regard to all phenomena known to
him, and the proposition that the refrangibility of a ray of
light cannot be altered by reflexion or refraction was a
great step in advance at the time. As constantly happens,
however, new facts require a revision of old dogmas, and
though Brewster could never be persuaded, Stokes showed
in an absolutely conclusive manner that certain substances
could, and did, alter the refrangibility, or, as we now should
say, absorbed the incident light and emitted it again with
different periods of oscillation. As fluor spar was one of the
substances possessing this peculiar property, Stokes called
the" whole series of phenomena " fluorescence."

The later years of Stokes' life centred largely in his
activity as Secretary of the Royal Society. The range of
his knowledge, the width of his sympathies, and his almost
infallible judgment, peculiarly fitted him for a position which
offered so many opportunities of advising striving men, and
guiding their researches into profitable directions. He died
an old man, but his scientific outlook always remained young.
New ideas pleased him, even when he could not agree with
them, and he delighted in any discovery that did not fit into
established theories.

Two years after Stokes graduated as senior wrangler and
first Smith's prize man, the same honours fell to John Crouch
Adams (1819-1892). There could be no sharper contrast
between two men of similar intellectual attainments than that
which marks the scientific life of the two mathematicians.
Stokes freely presented his knowledge and experience to
others, while to Adams we may apply with greater truth
what Maxwell said of Cavendish, that he cared more for
doing the work than for communicating it to others. How
much of this reserve was due to the events connected with
his first research it is impossible to say, but it is difficult
to believe that these left him entirely unaffected. For that
research was an arduous one, and should have led to the first
discovery of the planet Neptune, if the responsible astro-
nomers at the time had paid more attention to the calculations
of the young Cambridge mathematician. A full account of
the history of the new planet, from the pen of Simon
Newcomb, is published in the " Encyclopaedia Britannica,"

126 Britain's Heritage of Science

and we may here confine oursel ves to its salient features . When
the path of Uranus, the planet discovered by William
Herschel in 1781, was carefully examined by Alexis Bouvard
of Paris, it was found that it showed irregularities which could
not be accounted for by the gravitational action of the other
planets known at the time. Bouvard himself entertained
the idea that the discrepancies might be due to the attraction
of an ultra-Uranian planet, and an English amateur
astronomer, the Rev. J. T. Hussey, wrote in 1834 to Airy,
who was then Astronomer Royal, offering to make a search
for this planet, if some idea of the position could be given
him. Adams heard of and became interested in these
discussions as an undergraduate, and the following memo-
randum, in his own handwriting, dated 3rd July, 1841, is
still preserved : " Formed a design, in the beginnuig of this
week, of investigating, as soon as possible after taking my
degree, the irregularities in the motion of Uranus, which are
yet unaccounted for ; in order to find whether they may be
attributed to the action of an undiscovered planet beyond
it ; and, if possible, thence to determine the elements of its
orbit, etc., approximately, which would probably lead to its
discovery."

Having graduated in 1843, he at once set to work on the
problem. His first solution was communicated to James
Challis, the head of the Cambridge Observatory, in September
1845, and about the 1st of November of the same year he sent
his calculations to Airy, indicating the position at which the
new planet might be looked for. Although, according to the
American astronomer Newcomb, two or three evenings
devoted to the search could not have failed to make the planet
known, Airy was not satisfied, but sent a further enquiry to
Adams, which, apparently, was left unanswered. Mean-
while. Leverrier, a young French astronomer, had, at the
suggestion of Arago, taken up the same subject, and made
an independent calculation, which led to a position of the
unknown planet agreeing so closely with Adams', that Airy's
interest became seriously engaged, and he suggested to
Chalhs, on the 9th of July, 1846, to make a search for the
planet. Three weeks later Chain's started work in a leisurely
way, but was hampered by the want of a good star map.

John Crouch Adams 127

The delay was decisive, for, on the 18th of September,
Leverrier, who had apparently no telescope of sufficient
power at his command, wrote to Galle, an assistant at
the Berlin Observatory, and the search was commenced
on the 23rd. Star charts were at the time being prepared
under the auspices of the Berlin Academy of Sciences, and
one of them covered the critical region. The same night a
star was discovered which was not registered in the map,
and the following night its change of position proved that
it was the looked for planet. It was afterwards found that
Challis, in his sweeps, had observed the planet on the 4th of
August, but not having compared his observations with those
made subsequently, had failed to recognize it as a moving
object. Had he done so, the first discovery of Neptune would
have fallen to the credit of Cambridge. The relative merits
of Adams and Leverrier were warmly discussed, but history
quickly disposes of all such questions of priority. Whether
of two discoverers one is a few weeks ahead of, or behind,
the other, seems all important at the time, but very soon
the adjudgment of merit turns upon the manner in which
the work was carried out rather than on the calendar.
Nevertheless, when so much seemed to depend on being the
first in the field, the disappointment of a young man standing
on the threshold of his career must have been severe, and
we cannot absolve either Airy or Challis from blame.

Adams' subsequent work was unostentatious, but always
sound and thorough. We may note his investigations on
the secular acceleration of the moon's mean motion and on
the orbit of the swarm of meteors known as the Leonides.

After 1844 a series of eminent men passed in rapid
succession through the Mathematical Tripos. William
Thomson (Lord Kelvin) graduated in 1845, and- P. G. Tait
in 1848, but their period of activity is associated with
Glasgow and Edinburgh rather than with Cambridge. Edward
John Routh (1831-1907) was born at Quebec and took his
degree as senior wrangler in 1854. For many years he held
a unique position as a teacher in his University, and it may
be said that the Mathematical Tripos in its best days owed
much of its success to Routh. Such, at any rate, is the
testimony of many distinguished men to whose work this

128 Britain's Heritage of Science

country owes its pre-eminent position in the history of applied
mathematics. Routh's " Dynamics of Rigid Bodies " is much
more than a text-book, and has become almost a classic ; he
has also given us valuable contributions to the investigation
of the " stability " of motion.

Second to Routh in the Tripos list of 1854 stands Clerk
Maxwell, one of the men whose work forms one of the
great landmarks of science. But, as in the case of Kelvin,
much should be said in addition to what has already appeared
in the first chapter. The subject of colour vision attracted
Clerk Maxwell's attention at an early period, and his experi-
ments on the subject helped to establish Young's physio-
logical theory which reduced all colour sensations to three
primary effects. In dynamics his investigations on Saturn's
rings are fundamental. The conclusion arrived at is " that
the only system of rings which can exist is one composed
of an indefinite number of unconnected particles revolving
round the planet with different velocities, according to their
respective distances. These particles may be arranged in a
series of narrow rings, or they may move through each other
irregularly. In the first case the destruction of the system
will be very slow, in the second case it will be more rapid,
but there may be a tendency towards an arrangement in
narrow rings which may retard the process."

In pure mathematics, Cambridge in modern times gave us
Sylvester (1814-1897) and Cayley (1821-1895). Both started
life by being called to the Bar, but soon returned to their
favourite subject. Sylvester was second wrangler in the
Tripos of 1837, but, being a Jew, could not take his degree.
After four years' teaching at University College, London, as
Professor of Natural Philosophy, he accepted the Chair of
Mathematics at the University of Virginia in 1841. He
returned to England in 1845, and during the next ten years
was connected with a firm of accountants. In 1855 he
became Professor of Mathematics at the Royal Military
Academy, Woolwich, but on the foundation of the Johns
Hopkins University in 1877 he returned to the United States.
In 1883 he went to Oxford as successor to Henry Smith.
Sylvester's work dealt mainly with higher algebra and the
theory of numbers. He possessed great originality; his

J. J. Sylvester, A. Cayley 129

work is described as " impetuous, unfinished, but none the
less vigorous and stimulating."1 His efforts at poetry
may be noted, more especially as he possessed the unique
power of expressing Heine's songs in English verse. He was
also devoted to music, and at one time took singing lessons
from Gounod.

Cayley's contributions range over a wide field of modern
mathematics, and he ranks with the greatest mathematicians.
An idea of the nature of his researches may perhaps be given
by quoting the verses of Clerk Maxwell, composed to help
the promotion of a fund collected for a portrait to be painted
by Lowes Dickinson : —

O wretched race of men, to space confined !

What honour can ye pay to him, whose mind

To that which lies beyond hath penetrated?

The symbols he hath formed shall sound his praise,

And lead him on through unimagined ways

To conquests new, in worlds not yet created.

First, ye Determinants ! in ordered row
And massive column ranged, before him go.
To form a phalanx for his safe protection.
Ye powers of the nth roots of minus one !
Around his head in ceaseless cycles run,
As unembodied spirits of direction.

And you, ye undevelopable scrolls !

Above the host wave your emblazoned rolls,

Ruled for the record of his bright inventions.

Ye Cubic surfaces ! by threes and nines

Draw round his camp your seven-and-twenty lines —

The seal of Solomon in three dimensions.

March on, symbolic host ! with step sublime,
Up to the naming bounds of Space and Time !
There pause, until by Dickenson depicted,
In two dimensions, we the form may trace
Of him whose soul, too large for vulgar space,
In " n " dimensions flourished unrestricted.

In another branch of science William Hallowes Miller
(1801-1880) was a worthy colleague of the distinguished men
who encouraged the study of science at Cambridge. He

W, R. R. Ball, " A Short History of Mathematics."

I

130 Britain's Heritage of Science

graduated as fifth wrangler in 1826, and was elected to the
Professorship of Mineralogy three years later. The mathe-
matical knowledge he had acquired fitted him peculiarly to
deal successfully with that branch of his subject to which he
mainly devoted himself. He developed a new system of
crystallography, which rapidly gained acceptance owing to
its simplicity and mathematical symmetry. Miller also took
a great interest in primary standards, and had a large share
in the reconstruction of the standards of length and weight,
in 1839, after their destruction in the fire which broke out in
the Houses of Parliament.

We must postpone considering the achievements of a
younger generation of Cambridge men, including John
Hopkinson, George Darwin, John Poynting and others,
until the earlier work of other seats of learning has been
dealt with.

The Scotch Universities claim our first attention. At
the beginning of the nineteenth century Thomas Charles
Hope (1766-1844) enjoyed an unrivalled reputation as a
teacher. It is recorded that in 1823 he lectured to a class of
575 students. At the age of twenty-one he was appointed
Professor of Chemistry at Glasgow, but resigned soon after
to become Assistant Professor of Medicine. In 1795 he
settled down at Edinburgh, as joint Professor of Chemistry
with Joseph Black, becoming sole Professor of the subject at
the latter's death in 1799. Hope discovered the important
fact that within a certain range of temperature just above
the freezing point, water does not behave like ordinary
substances, expanding when the temperature is raised, but
contracts, reaching a point of maximum density near 4° C,
This is a matter of considerable importance in the economy
of nature, for when in the cold of winter the temperature
of a sheet of water sinks below the critical point, the colder
water is also the lighter. Hence ice first appears as a thin
layer on the surface, while the main body can be in stable
equilibrium below at a temperature higher than the freezing
point. But before the ice can form at all, the whole mass
must have cooled down below 4° C. Hope also had an
important share in the discovery of the element strontium.
A mineral discovered at Strontian in Argyllshire in 1787

W. H. Miller, T. C. Hope, J. Leslie 131

was at first believed to be a carbonate of barium. Dr. Craw-
ford threw doubt on this, and suggested that it contained a
new substance, and this was confirmed and definitely proved
by Hope.

John Playfair's successor in the Chair of Mathematics at
Edinburgh, and subsequently in that of Natural Philosophy,
was John Leslie (1766-1832). After passing through the
University as a student of Mathematics and then of Divinity,
he spent a year as private tutor in Virginia, and subsequently
in the family of Josiah Wedgwood, where he devoted his
leisure to Natural Science, translating Buffon's " Natural
History of Birds." Returning to his native place, Largo,
in Fifeshire, Leslie devoted ten years to scientific research,
and then settled down at Edinburgh University. He received
the honour of knighthood shortly before his death. Leslie's
name is generally connected with his researches on radiation,
which would have been more fruitful had he been less
dogmatic in upholding what he conceived to be Newton's
teaching. He refused to recognize the obvious bearing of
Herschel's discovery of radiations less refrangible than red
light, and formed artificial and erroneous theories to
explain the facts. Nevertheless, his experiments on the
radiative power of different substances were conducted with
great skill and are of permanent value. The differential
thermometer, he employed, maintained for a long time its
reputation as a delicate and trustworthy instrument. We
owe to him also a valuable method of determining the specific
heats of bodies by measuring their rate of cooling. He was
the first to freeze water by evaporating it rapidly under the
action of an air pump, the vacuum being maintained by
sulphuric acid, which rapidly absorbed the aqueous vapour
formed. He was also the first to give the correct explanation
of the rise of liquids in capillary tubes.

David Brewster (1781-1868), a man of forceful character
and great ability, enjoyed a considerable reputation among
his contemporaries, but the weight of his influence was not
always placed in the right scale. Like Leslie, he adhered
to a verbal interpretation of Newton's doctrine, and in
face of the rapidly growing and decisive evidence in favour
of the undulatory theory of light, his attitude exceeded all

I 2

132 Britain's Heritage of Science

reasonable limits. Even when Fizeau had made his crucial
experiment and shown that the velocity of light in ordinary
refracting bodies was smaller than in air and not greater, as it
should be according to the corpuscular theory, Brewster
refused to admit the validity of the evidence.1 Nevertheless,
Brewster was a great experimenter, though an unkind
Nemesis turned his most important investigations into an
armoury which supplied effective weapons to his opponents.
He studied the laws of polarization by reflexion and refraction
both for transparent and metallic media; he discovered
the connexion between the refractive index and polarizing
angle, and the double refraction due to strain. He also first
examined crystalline plates under the polariscope in diverging
light. He was a prolific writer, and contributed many articles
to the early editions of the " Encyclopaedia Britannica." He
is said to have given the first impulse to the foundation of
the British Association, and was one of its chief supporters
during the first years of its existence.2

While Brewster was battling in vain against the tenets of
modern physics, a young Scotsman, equally distinguished
as an experimenter, but superior in judgment and scientific
insight rapidly rose to eminence. James David Forbes
(1809-1868) was the fourth son of Sir William Forbes,
seventh baronet of Pitsligo. He entered the University of
Edinburgh at the age of sixteen, and soon afterwards con-
tributed anonymously to the Edinburgh Philosophical Journal.
At the age of twenty-three, which even then must have been
a quite exceptionally early age, he was elected a Fellow
of the Royal Society. In 1833 he was appointed Professor
of Natural Philosophy at Edinburgh University in succession
to Sir John Leslie, Sir David Brewster being the com-
peting candidate, and in 1859 he succeeded Brewster in the

1 The authority for this statement is an oral communication by
Stokes.

2 In the " Encyclopaedia Britannica," eleventh edition, it is stated t
"In an article in the ' Quarterly Review,' he threw out a suggestion
for * an association of our nobility, clergy, gentry and philosophers *
which was taken up by others, and found speedy realisation in the
* British Association for the Advancement of Science.' " No such
article can be found in the " Quarterly Review."

D. Brewster, J. D. Forbes, P. G. Tait 133

Principalship of the United College of St. Andrews. His
demonstration of the polarization of heat by all the various
means by which ordinary light acquires that property, was
an experimental achievement of the highest rank, and was a
powerful link in the chain which connects the phenomena of
radiation. In another series of researches, Forbes appears
as one of the pioneers in the important but often neglected
field of Geo-physics. He was the first to conduct systematic
observations on the temperature of the earth, by inserting
thermometers reaching down to different depths beneath
the soil, in such a manner that they could be read off without
disturbing them. Such experiments allow us to measure the
thermal conductivity of the soil, and the loss of heat of the
earth through radiation. Later on he determined the thermal
conductivity of metals, and discovered that this conduct-
ivity diminished as the temperature increased. During a
number of visits to Switzerland he investigated the flow of
glaciers, and showed that the movement of the ice of glaciers
followed the laws of viscous bodies. The tremors of the
earth caused by earthquakes also occupied his attention,
and he constructed an instrument which was not sufficiently
sensitive, but must be considered as the forerunner of the
modern seismographs.

Passing on to more recent times, the name of Peter Guthrie
Tait (1831-1900) has already been mentioned as belonging
to the Cambridge school of mathematics. The work of his
life was devoted to the Edinburgh University, where his
teaching of Natural Philosophy exerted a wholesome, though
perhaps restraining, influence on the many students who
passed through his hands. While he will be remembered
chiefly as a vigorous apostle of the doctrine of energy and a
forceful propagator of sound dynamical ideas, he made
substantial contributions to science, and the " Elements of
Natural Philosophy," written jointly by Thomson and Tait,
though ^never completed, is a monument " more permanent
than bronze." Associated with Tait as a prominent Univer-
sity teacher, the name of Crum Brown, Professor of Chemistry
between 1869 and 1908, will be remembered by many
students who passed through his hands.

George Chrystal (1851-1911), another Cambridge man

134 Britain's Heritage of Science

whom death has too soon removed, occupied the Chair of
Mathematics at Edinburgh from 1879 to the end of his life.
He was a brilliant teacher, possessing one of those clear and
critical minds which care more for the quality than the
quantity of their work. Everything that flowed from his
pen was of the highest standard. He had the distinction
of being the first to carry out original investigations in the
Cavendish Laboratory at Cambridge, where he tested the
truth of Ohm's law to a degree of accuracy far surpassing
all previous work. He published a " Treatise on Algebra "
and several papers of a mathematical character. During
the last years of his life he was occupied with an interesting
investigation on the oscillations of level (" seiches ") in the
Scotch lakes, initiated by Forel's observations at the Lake of
Geneva.

Glasgow University was naturally dominated during a
great part of last century by Lord Kelvin's prodigious
activity. His work on heat has already been described; his
contributions to the practical applications of science will be
referred to later, and as regards his researches on hydro-
dynamics and other parts of Mathematical Physics, the
reader must be referred to special treatises.

During a period of forty years, Philip Kelland (1808-
1879) taught mathematics at the same University, but his
published work deals mainly with the undulatory theory of
light, and is concentrated into a few years following his
degree course at Cambridge

The University of Glasgow rendered one of the most
important services that have ever been conferred both on
science or on industry when, in 1840, it founded, under the
auspices of Queen Victoria, the first Professorship of Civil
Engineering in the United Kingdom. The second holder of
the Chair, W. J. Maquorn Rankine (1820-1872), stands out
as a man of striking originality and a great teacher. Most
of his early instruction was received at home. Before he
entered the University of Edinburgh, at the age of sixteen,
he had already studied Newton's " Principia." He then
became engaged in various engineering enterprises, until he
was appointed Professor of Engineering at Glasgow in 1855.
Rankine was one of the imaginative men who are not satisfied

G. Chrystal, W. J. M. Rankine, J. Thomson 135

with the summary of facts contained in a mathematical
formula, but require a definite picture of atoms and molecules,
whose dynamical interactions he tried to trace in their details.
He invented theories on the causes of elasticity, the constitu-
tion of gases, and the motion which constitutes heat. But
while most of these theories had to be abandoned, the use
which he made of them, and the consequences he drew from
them, remained, because they were founded on true dynamical
principles, and the results proved in many cases to be inde-
pendent of the particular hypothesis from which they happened
to be derived. Inspired by Joule and Kelvin, the dynamical
theory of heat occupied much of his attention, and he was
an early convert to the doctrine of the conservation of
energy. We owe to him the introduction of the term
" potential energy," one of the happy inspirations which,
furnishing an appropriate nomenclature, allowed the funda-
mental principle of the conservation of energy to be expressed
in a crisp and impressive form. Among his more technical
papers, the most important ones deal with stream lines,
the efficacy of propellers, and the construction of masonry
dams. Rankine was an accomplished musician, and occa-
sionally indulged in poetry. Some of the songs composed
and set to music by himself were published in a separate
volume.

Rankine 's successor at Glasgow University, James Thom-
son, was a man of almost equal distinction. Like his brother,
Lord Kelvin, he never went to school. The two brothers
passed through the University together, and James took
his M.A. degree at the age of seventeen. He was for a time
apprenticed to Messrs. Fairbairn at Manchester, but bad
health obliged him to return home, where he occupied himself
with the invention of appliances for the better utilisation
of water power. At various periods of his life he returned
to the subject, and we owe to him several forms of water-
wheels, a centrifugal pump, and improvements in turbines.
At a meeting of the British Association in 1874 he described
a pump for drawing up water by the power of a jet, which
led to the construction of such pumps on a large scale. Among
his purely scientific contributions, that on the lowering of
the freezing point of water by pressure is the most important.

136 Britain's Heritage of Science

From purely theoretical considerations, James Thomson was
able to predict that the freezing point of water must be
lowered by pressure. His starting point was that water
increases in volume on being converted into ice, and the
reasoning depends on an application of the second law of
thermodynamics. The fact itself was verified soon afterwards
by Lord Kelvin, and though the change in the freezing point
only amounts to three quarters of a degree Centigrade for
100 atmospheres, it yet plays an important part in the
behaviour of glaciers, for it explains the plasticity of ice
discovered by Forbes. The binding together of snow by
the pressure of the hand is also a consequence of the partial
melting by pressure, and solidification when the pressure is
removed.

Scotland claims also Sir William Rowan Hamilton (1805-
1868) as one of its great men, though his life was spent in
Dublin, where his father — a solicitor — had settled as a
young man. The genius of men possessing exceptional
mathematical powers frequently shows itself at a very early
age, and Hamilton was no exception to this rule. But
even before he had an opportunity of discovering his own
powers in that direction, he showed a wonderful facility of
acquiring foreign languages. At the age of thirteen he
is reported to have learned Persian, Arabic, Sanskrit, and
Malay, besides the classical and modern European languages.
At the age of sixteen he had mastered Newton's " Principia "
and the " Differential Calculus," and soon after began a
systematic study of Laplace's " Mecanique Celeste." When
he was eighteen years old Dr. John Brinkley, the Astronomer
Royal for Ireland, is said to have remarked : " This young
man, I do not say will be, but is the first mathematician of
his age." He entered Trinity College, Dublin, but before he
had taken his degree, his career as a student was cut short
by his appointment to the Professorship of Astronomy at the
Dublin University, and he established himself at the Dunsink
Observatory. To all students of Mathematics and Physics,
" Hamilton's Principle " is known as one of the fundamental
instruments of dynamics, which may be applied to nearly all
natural phenomena.

Hamilton's first investigation on " Systems of Rays "

Sir William Rowan Hamilton 137

led to an optical discovery that created considerable interest
at the time because it drew attention to a curious phenomenon
of refraction in biaxal crystals which had not previously
been noticed. According to Fresnel's theory, there are in
such crystals two directions such that a ray passing along
them will emerge as a conical pencil. It follows that, under
certain experimental conditions, the two spots of light
produced by double refraction are spread out and joined so
as to form a ring. Hamilton's prediction was immediately
verified by Humphrey Lloyd, and was received as a striking
confirmation of Fresnel's theory.

The later years of Hamilton's lif e were spent in developing
the new calculus of " Quaternions," to which he attached
great importance; but, though it has yielded methods of
great elegance, it has not quite fulfilled its early promise,
and has few adherents at the present time. Some of its
conceptions, however, permanently survive in the modern
vector analysis.

No single teaching institution has a higher record of
scientific output during the last century than Trinity College,
Dublin. Humphrey Lloyd, James McCullagh, John Hewitt
Jellett, George Salmon, Samuel Haughton, George Francis
Fitzgerald, Charles Jasper Joly are names that any University
would have reason to be proud of. Lloyd (1800-1881) has
already been mentioned in connexion with the verification
of conical refraction. In later years he devoted much time
to the study of terrestrial magnetism, and took an active
part in the magnetic survey of Ireland. James McCullagh
was an eminent mathematician whose contributions to the
undulatory theory of light take a conspicuous place in the
history of that subject. Jellett (1817-1888), like McCullagh,
was a mathematician, primarily attracted more by physical
and even chemical problems than by pure theory. He is,
perhaps, best known for his improvement of the experimental
methods for studying the rotation of the plane of polarization,
observed in certain bodies like sugar. George Salmon (1819—
1904), for many years Provost of Trinity College, confined
himself to problems of Pure Mathematics, notably in the
domain of Geometry. Samuel Haughton (1821-1897) was
primarily a geologist, but his versatile mind made frequent

138 Britain's Heritage of Science

excursions into other subjects, partly suggested to him by
his interest in the structure of the earth, but partly discon-
nected entirely from his main work, such as his investiga-
tions on some problems of sound and light and on the
velocity of rifle bullets. He claimed amongst other achieve-
ments to have been the originator of the " long drop " in
capital punishment.

Of G. F. Fitzgerald (1851-1901) we cannot speak
without lamenting the loss inflicted on science by his early
death, He was one of the select few whose genius extends
beyond the limits of their own productive work, stimulating
the thoughts and penetrating the efforts of their contempo-
raries. One of the earliest students of Maxwell's electro-
magnetic theory, he realized probably more than anyone
else its wonderful future. Of the practical applications of
wireless telegraphy he had no thought — his interests lay in
other directions — but he felt that the final proof of the theory
must be sought in the experimental confirmation of the
transmission of electro-dynamic waves through space, and
saw that the difficulty to be overcome was the power
necessary to convey the energy from the metallic conductors
to the medium. His thoughts even ran ahead of Maxwell's
theory, and he escaped the common error of apostles
of a new doctrine, who adopt the unavoidable limita-
tions of a first presentment as an immovable dogma,
mistaking the passing faults of a child for essential features
of its character. It was a necessary step in the evolution
of the Faraday-Maxwell conception of electrical action that
an electric current should be looked upon as the flow of a
coherent substance satisfying everywhere the condition of
incompressibility. But when the relation between electrical
actions and molecular phenomena were considered, the
laws of electrolysis suggested that, like matter, electricity
might have an atomic constitution. Most of the professed
adherents of Maxwell's doctrine would have none of this
idea. It seemed to them to violate the dogma of incom-
pressibility. But Fitzgerald recognized that there was no
real contradiction, and he became one of the great advocates
of the electron theory. In this, as in other matters, his
mind was receptive and appreciative of the efforts of others,

G. P. Fitzgerald, G. Johnstone Stoney 139

and his generous disposition made him a willing helper of
all who were seeking advice. Though his influence on con-
temporary thought was all the greater in consequence, the
output of his own work was interfered with.

Scientific education in Ireland owes much to George
Johnstone Stoney (1826-1911), the uncle of Fitzgerald, and
for many years, up to the time of its dissolution in 1882,
the Secretary of Queen's University. During twenty years
he acted in the same capacity to the Royal Dublin Society,
an institution founded in 1731 for promoting the arts and
industries of Ireland. As an original investigator Stoney
was distinguished by a philosophical and balanced mind,
but his work was suggestive rather than conclusive. He
showed remarkable foresight when he interpreted the true
significance of Faraday's laws of electrolysis as indicating
the atomic nature of the centres of electric action, and he
gave the name of " electron " to the ultimate constituent of
electricity.

When the Queen's Universities were founded in 1845,
the appointment of first Vice -President at Belfast fell to
Thomas Andrews (1813-1885), a man of remarkable gifts
and quite exceptional experimental powers. After a course
of study of chemistry at Glasgow University and — for a
short time — under Dumas at Paris, he took the degree of
Doctor of Medicine at Edinburgh, and then returned to
practise medicine at Belfast. But the call of science was
too strong, and he accepted the appointment at Queen's
College, which was combined with the Professorship of
Chemistry. Andrews' first paper, published in 1836, dealt
with a question which has since acquired considerable
importance : "On the conducting power of certain flames
and of heated air for electricity." He next devoted him-
self to the study of the heat developed in chemical com-
binations. His work gained in importance as he proceeded,
and together with Tait he was the first to demonstrate the
true nature of ozone, proving it was only an allotropic form
of oxygen. The research for which he is most renowned
is that dealing with the liquefaction of gases. When Faraday
had succeeded in liquefying carbonic acid, chlorine, and other
vapours by pressure, the question naturally arose whether

140 Britain's Heritage of Science

all gases could be converted into liquids. Pressure alone
seemed ineffective with gases like oxygen, nitrogen, and
hydrogen, but that might have been due to our inability to
apply sufficient power. Andrews, investigating the condi-
tions under which carbonic acid could be liquefied, and taking
exact measurements of the pressure required at different
temperatures, discovered that there was a critical temperature,
such that, if the gas be heated above it, no pressure, however
great, could convert it into a liquid. Previous experiments
by Cagniard de la Tour and others had foreshadowed such
a result, and Faraday came very near to the true solution
cf the problem, but this does not detract from the value of the
classical research by which Andrews finally established his
results. We have seen in our own time how, in the hands
of Sir James Dewar and of the Dutch physicist, Kammer-
lingh Onnes, the subject has developed into a new branch of
science, enabling us to investigate the properties of bodies
at temperatures so low that molecular motion is almost
annihilated.

The reputation of Oxford University as a centre of
research did not, during the last century, rest on its activity
in scientific pursuits; but it had among its teachers and
pupils at any rate one man whom any seat of learning would
have been proud to claim as its own. Henry John Stephen
Smith (1826-1889) was both a brilliant mathematician and
a great man. He was born in Ireland, but after his father's
death his mother removed to the Isle of Wight, and it was
there that Henry Smith received his first education. After
a short time spent under a private tutor, he went to Rugby,
where he became head boy under Dr. Tait. In spite of
ill-health, which for some time interrupted his studies, he
obtained a Balliol scholarship in 1844, the Ireland scholarship
in 1848, and a first-class both hi the classical and mathe-
matical schools in 1849. In the meantime he had spent a
winter in Paris, where in 1847 he attended the lectures
of Arago and Milne Edwards. In 1861 he was elected
to the Savilian Professorship of Mathematics as successor
to Baden Powell. His researches on the theory of numbers
and the elliptic function placed him in the front rank of
mathematicians; and he showed the same perfect mastery

Thomas Andrews, Henry Smith 141

over every subject he touched. The reader is referred to
the excellent obituary notice from the pen of Dr. J. W. L.
Glaisher for an account of the extent and value of his
researches.1 With regard to his teaching capacity, those
who remember him will agree with Dr. Glaisher that : "As
an expounder of mathematics before an audience he was
unsurpassed for clearness, and his singular charm of manner
gave him a remarkable power for fixing the attention of those
present."

His sound judgment was often called upon by others;
he was a member of the Royal Commission on Scientific
Instruction (1870), and of the Oxford University Commission
(1877). During the last sixteen years of his life he acted as
Chairman of the Meteorological Council and devoted much
time to the work. Quoting again from Glaisher's obituary
notice : " It is difficult to give an idea of the position
Professor Smith held in Oxford and in society generally,
so brilliant were his attainments and so great and varied
his personal and social gifts."

Though Henry Smith was the greatest of the scientific
men who taught at Oxford, mention should be made of
Odling, the Professor of Chemistry, and Vernon Harcourt,
inventor of the pentane lamp as a standard of light. The
optical work of Baden Powell has already been referred to,
and it will be remembered that Sylvester for a time taught
at the same University, succeeding to the Professorship
vacated by the death of Henry Smith. The revival of
astronomical research at Oxford owes much to the efforts of
Charles Pritchard (1808-1893), who, on his appointment to the
Savilian Professorship, succeeded in persuading the authori-
ties to erect a new observatory, and to provide an adequate
equipment. Pritchard, after graduating as fourth wrangler
at Cambridge, had spent nearly thirty years as Headmaster
of Clapham Grammar School. After his retirement in 1862,
he undertook some clerical duties, began to take an active
interest in astronomy, and filled the office of Hon. Secretary,
and subsequently of President, of the Royal Astronomical
Society. When he was appointed to the Chair of Astronomy

* " Monthly Notices," Roy. Ast. Soc., Vol. XLIV., 1884.

142 Brilahr.s llrri(;i;r <>!' Srinuv

;il ()\lord lir \\;IM already M\ly lluvr \(';ir,'; old, l>ul nover-
1 liohvs i c IK Ti.'c I ic.dl \ 01 .".uir/.cd I lir uc\\ ( )l».scr\ .1 1 « >r\ Trite hard
\\an «MKN ol lln> oiirly iidvociitr.s ol (lie HMO (>f photography

III .1,1 i < MM Miiic.M I i c: CM I ell , .'Hid :,lio\\cd IlONN ll could l>c .Mpplird
to obtain accurah^ nicM.-.iiicincntM, and ill photoiurt lit'
dt^tonuinat IOIIM.

143

CHAPTER V

(Physical Science)

THE HERITAGE OF THE NINETEENTH CENTURY—
continued

rilHE foundation of the University of London, followed
JL by that of the newer Universities, plays so important
a part in the liistory of our subject that a few words must
be said on the origin of the movement. It arose not so much
out of a feeling that the number of Universities in the country
was too small, but in consequence of the religious exclusive-
ness of Oxford and Cambridge, which only admitted adhe-
rents of the Church of England to University honours. In
October 1828, therefore, a number of Nonconformists of
various religious denominations combined, and University
College was opened as the " University of London," with
power to grant degrees. Unfortunately, some influential
persons, though favourably inclined to the scheme on educa-
tional grounds, objected to its entire dissociation from the
national church, and successfully pressed their objections.
At the present time the difficulty — such as it is — would be
met by the establishment of a religious Hall of Residence,
but no one thought of that expedient, and King's College was
founded for the purpose of combining secular teaching with
instruction in " the doctrines and duties of Christianity, as
the same are inculcated by the Church of England and
Ireland."

The University of London then became a mere examining
body, granting degrees, without control of the teaching, while
University College received a new charter, without the power
of conferring degrees. Among its first Professors was
Augustus do Morgan (1806-1871), who was elected to the

144 Britain's Heritage of Science

post a year after he had graduated at Cambridge as fourth
wrangler. De Morgan, the son of a Colonel in the Indian
Army, was born at Madras, but brought to England as a
child. He combined exceptional mathematical talents,
inherited from his mother, with great powers of exposition,
and his lectures attracted many men of distinction. Original
in his views and his methods, and possessing great strength
of character, he followed the dictates of his conscience
without regard to consequences. Shortly after his appoint-
ment at University College, he sent in his resignation
because a colleague, the Professor of Anatomy, had been
dismissed without assigned cause. He subsequently con-
sented to be re -appointed when the regulations had been
altered so as to prevent a repetition of similar incidents.
Ultimately he severed his connexion with University College
because the governing body took too narrow a view of the
religious neutrality of the college, and refused to appoint
Dr. Martineau to one of its Chairs on the ground that he
was pledged to Unitarianism. But we are here concerned
with his scientific productions. His work on the Differential
Calculus is one of those rare books which never seem to
become antiquated. Its introductory chapter gives us what
is probably the best exposition of the fundamental principles
of the Calculus that has yet been given. De Morgan's
" Budget of Paradoxes," reprinted after his death from
articles that had appeared in the Athenceum, contains,
besides an historical account of the vagaries of circle-squaring
and the trisection of angles, the views of the author on many
subjects. Like many mathematicians, De Morgan was
devoted to music ; he was a good player on the flute, and had
also a talent for drawing caricatures.

Thomas Graham (1805-1869), the first of the series of
great chemists who have adorned the laboratories at Gower
Street, commenced his studies at Glasgow, and after com-
pleting them under Hope and Leslie at Edinburgh, returned
to the former city, where for a short time he held the Chair
of Chemistry. When in 1837 he was called to University
College, London, as Professor of Chemistry, he had already
established his reputation as an original investigator. His
chief interest was centred in the study of those physical and

A. de Morgan, T. Graham, W. H. Wollaston 145

chemical properties which may be expressed in terms of
molecular motion. The connexion between the density of
gases and the velocity of their diffusion was first investi-
gated by him in 1828, but established with greater precision
ten years later. The conclusion arrived at, that the velocity
of the diffusion is inversely as the square of the density,
proves, in the light of subsequent investigation, that the
molecules of different gases have — at the same temperature
— the same energy of motion. Graham's investigation
covered the whole field, including the inter-diffusion of
different gases, their transpiration through capillary tubes,
and their effusion into a vacuum, the peculiarities being
carefully examined in each case. A further series of papers
dealt with molecular motion in liquids, and established
the distinction between the inert " colloid " and the more
rapidly diffusing " crystalline " substances. These have had
important consequences, and we now know that in the col-
loidal state we are dealing with molecular aggregates of com-
paratively large dimensions, the greater individual masses
accounting for the slowness of the movements. Graham's
experiments on the passage of liquids through certain
membranes opened out a fruitful field of research on the
phenomenon called osmosis, which has recently gained
great importance. In the domain of pure chemistry, a paper
" On water as a constituent of salts " led to results of interest,
more especially through the discovery of the polybasic
nature of phosphoric acid.

W. H. Wollaston (1766-1825), a medical man who gave
up his practice in order to devote himself to the study of
chemistry, had, in the course of his researches on platinum,
discovered two new elements, palladium and rhodium.
Investigating the peculiar power which palladium has to
absorb hydrogen, Graham came to the conclusion that
hydrogen, like a metal, could form alloys, and connecting
this with the chemical behaviour of this element in other
respects, he formed the idea that it was the vapour of a highly
volatile metal, to which he gave -the name of " hydrogenium."
The expectation then raised was that hydrogen when con-
densed into the liquid or solid form would present the
characteristic appearance of a metal, but this was not

K

146 Britain's Heritage of Science

confirmed when Sir James Dewar actually accomplished the
condensation.

University College during Graham's time had two
Professorships of Chemistry, that of " Practical Chemistry "
being held by George Fownes (1815-1849), who, on his
death four years after the appointment, was succeeded by
Alexander M. Williamson (1824-1904). Like Graham, he
was of Scotch descent, but his education was cosmopolitan.
After attending schools in London, Paris, and Dijon, and
studying chemistry during five years in Germany, he stayed
three years in Paris and then returned to England. His
most important contribution to science is that which eluci-
dated the chemical process by which ether is formed when
alcohol is brought into contact with hot sulphuric acid.
Apart from the intrinsic importance of the subject, the
research illuminated a number of problems in chemical
dynamics, and led to a better understanding of " catalytic "
actions, by which the presence of a body induces chemical
transformations without itself being apparently involved in
the change. Organic chemistry owes to Williamson many
other fruitful ideas. In inorganic chemistry his views on
the constitution of salt solutions, though essentially different
from our present ideas of " ionization," yet come sufficiently
near to them to have prepared the way for the readier
acceptance of the theory subsequently developed by Arrhe-
nius. They held the field for a time, and made the process
of electrolysis more intelligible,

Williamson played an important part in the scientific
life of London ; his was a well-known figure at the meetings
of the Chemical Society, and he started the publication, in
its Journal, of the monthly reports of all papers of a chemical
nature published elsewhere. He acted as Foreign Secretary
to the Royal Society during sixteen years, and also assisted
the efforts made at various times to convert the University
of London into a teaching body. In 1855, when Graham
resigned the Chair of Chemistry in University College on
becoming Master of the Mint, the two Professorships were
united, and Williamson continued to hold the combined
Chairs until 1886.

One of Williamson's colleagues at University College,

A. Williamson, C. Wheatstone 147

whose brilliant career was cut short by premature death, may
here be referred to. William Kingdon Clifford (1845-1878),
second wrangler in 1867, held the Chair of Applied Mathe-
matics during eight years, but was stricken with tuberculosis,
and died in Madeira. He has left many important con-
tributions both to applied and pure mathematics.

Among the Professors at King's College appointed at
or shortly after its foundation were two men of world-wide
reputation, John Frederick Daniell (1790-1845) and Charles
Wheatstone (1802-1875). Daniell constructed the first
electric cell which was free from the irregularities caused by
polarization, so that constant currents could be obtained.
He was mainly interested in meteorology, and rendered
valuable services in insisting on accurate and systematic
observations of the various phenomena on which the physics
of the atmosphere depends. His most successful instrument
was that by means of which the humidity of the air is
determined from the temperature at which dew begins to
deposit.

Wheatstone began his career as a maker of musical
instruments, and during the ten years 1823 to 1833
published a number of papers on sound. In 1831 he was
appointed to the Chair of Natural Philosophy at King's
College, and three years later conducted some experiments
which were devised to measure the velocity with which
electrical effects are transmitted along a wire, and the
duration of an electric spark. In these experiments a rotating
mirror was first used to measure small intervals of time.
He was also one of the first to recognize the importance of
Ohm's law, and to insist on accurate standards and good
methods of measuring electromotive force, resistance and
current. The Bakerian Lecture for 1843 contains a descrip-
tion of the methods employed by him, including the arrange-
ment of wires now familiar to every student of science
under the name of the " Wheatstone bridge." As he points
out himself, the arrangement was first used by Samuel
Hunter Christy (1784-1865), Professor of Mathematics at the
Military Academy, Woolwich.

Wheatstone was the first to show how a number of clocks
can simultaneously be regulated by the electric current.

K 2

148 Britain's Heritage of Science

In Optics he invented the stereoscope and conducted valuable
experiments on the physiology of vision. At the British
Association in 1871 he exhibited an instrument by means
of which the solar time could be determined by utilizing
the polarization of the blue light of the sky. This method,
as he explained, has several advantages over the ordinary
sundial. Wheatstone's spectroscopic observations and his
contributions to telegraphy will be referred to in another
place (see pp. 154, 188).

The first sight that meets the eye of a visitor entering
the Town Hall of Manchester is the statue of Dalton on
his left, and that of Joule on his right. These two great men
found a congenial home in the town which numbered amongst
its citizens others who, long before it became the seat of a
University, upheld the dignity and usefulness of its Literary
and Philosophical Society. Such were Thomas Henry (1734-
1816), the author of valuable investigations in Chemistry;
his son, William Henry (1774r-1836), who studied the laws
of absorption of gases by liquids, and William Sturgeon
(1783-1850), the inventor of the electro -magnet, who started
life as a shoemaker, entered the army as artillerist, became
teacher of physics at the military academy of the East India
Company, and spent the last twelve years of his life in
scientific investigations at Manchester. The ambition of that
town to become the seat of a University dates back to the
seventeenth century, and though renewed at various times
long remained unsatisfied. By the will of John Owens, who
died in 1850, a college was founded, which after a period
of difficulty rapidly rose to eminence. It numbered among
its first professors Edward Frankland (1825-1899), whose
researches were fundamental in the development of modern
chemistry, and who, next to Davy and Dalton, must pro-
bably be considered to be the greatest chemist this country-
has ever produced. Having discovered a number of organic
substances containing metallic atoms as essential consti-
tuents, he investigated the general laws of the formation of
chemical compounds, and originated the conception that
the atom of an elementary substance can only combine with
a certain limited number of atoms of other elements. This
led to the discovery of " valency " as the groundwork of

E. Frankland, H. E. Roscoe 149

chemical structure. Frankland only stayed six years in
Manchester; on returning to London, he became lecturer
in Chemistry at St. Bartholomew's Hospital, and subse-
quently Professor of Chemistry at the Royal Institution
and the School of Mines. The latter years of his life were
spent in work connected with the examination and purifica-
tion of the water supply. He was made a K.C.B. in 1897,
two years before his death.

When Frankland, in 1857, resigned his position at
Manchester, the choice of a successor lay between Robert
Angus Smith (1817-1884) and Henry Enfield Roscoe (1833-
1915). The former was personally known in Manchester,
where he resided, and had already done some meritorious
work on the impurities found in the air and water of towns,
a subject to which he devoted the greater part of his life.
Roscoe was only twenty-four years old, but the promise of
future success was already foreshadowed in his academic
career, and fortunately for Owens College, whose fortunes
were then at a low ebb, he was elected to the Professorship.
At the age of fifteen, Roscoe had entered University College,
London, where he came under the influence of Thomas
Graham and Alexander Williamson. After taking his B.A.
degree at the University of London, he spent four years at
Heidelberg under Bunsen. His activity in Manchester is
marked by the foundation of a school of chemistry through
which many men of high distinction have passed, and by the
happy relations which he established between the industrial
community and the academic life which was centred in the
college. The prosperity of that institution was soon secured
by his strong and genial personality, and when other men
eminent both in science and literature had joined its staff,
its rise to the dignity of an University became only a question
of time. Roscoe was one of the first to point out the need
of technical education in this country, but he did not interpret
that term in a narrow sense. With him it meant a sound
scientific instruction directed towards industrial ends, but
not excluding a wider culture. He served on the Royal
Commission on Technical Education appointed in 1881, and
at the conclusion of its labours received the honour of
knighthood. His earnest desire to spread the knowledge and

150 Britain's Heritage of Science

appreciation of science led him to organize a series of
popular penny lectures which attracted large audiences,
who had the privilege of listening to such men as Huxley,
Huggins, Stanley Jevons, Clifford, and others scarcely less
eminent.

Roscoe's first scientific investigations dealt with the
chemical action of light. The subject was suggested by
Bunsen, and partly carried out in conjunction with him.
Apart from the purely scientific interest attaching to the
effect of light in inducing hydrogen and chlorine to com-
bine, the research was conducted with the practical object
of obtaining a means of measuring the actinic value of day-
light under different atmospheric conditions. His principal
contribution to pure chemistry consists in his investigation
of the element vanadium, which established its true position
as a trivalent element of the phosphorus group, and showed
that the substance Berzelius had considered to be the metal
was really its nitride.

Among Roscoe's colleagues at Manchester who have
helped to establish the reputation of Owens College as an
important centre of scientific research, two men stand out
prominently: Balfour Stewart (1828-1887) and Osborne
Reynolds (1842-1912). It was probably fortunate that a
mind of such striking originality as that of Reynolds was
never submitted to the discipline of school, though it is
difficult to believe that even the severest group-education
could have shaped it into a common mould. His father was
a clergyman who had passed through the Mathematical
Tripos as thirteenth wrangler. The son was brought up at
home, and entered the workshop of an engineer at the age
of nineteen. He soon found that a knowledge of mathematics
was essential to work out the problems that presented them-
selves to him, and he decided to go to Cambridge, where he
graduated as seventh wrangler in 1867. He then returned
to the office of a civil engineer in London, but within a year
offered himself as a candidate for the newly-founded Pro-
fessorship of Engineering at Owens College. He remained
connected with that institution from 1868 to 1905, when
he retired owing to failing health. In his methods of
instruction Reynolds was a follower of Rankine ; his lectures

Henry E. Eoscoe, Osborne Reynolds 151

were sometimes difficult to follow, but capable and earnest
students always derived great benefit from them, and he
brought up a number of distinguished men who look back
with gratitude and affection to the inspiration they received
from his instruction.

His researches nearly all possessed fundamental import-
ance. To quote Horace Lamb1 : —

" His work on turbine pumps is now recognized as
having laid the foundation of the great modern develop-
ment in those appliances, whilst his early investigations
on the laws governing the condensation of steam on metal
surfaces, and on the communication of heat between a
metal surface and a fluid in contact with it, stand in a
similar relation to recent improvements in boiler and
condenser designs."

He laid the scientific foundation of the theory of lubrica-
tion, and his papers on hydrodynamics have become classical
both on account of their theoretical importance and practical
applications. Like Rankine, his mind was not satisfied with
finding useful applications of his scientific knowledge, but
he took an active interest in all questions which touched the
foundation of elemental forces and atomic structure. He
was the first to give the correct explanation of Crookes'
radiometer, and in his later years he tried to formulate a
structure of matter and sether which should account for
gravitation as well as for electrical and other forces. What-
ever may be the ultimate fate of these speculations, they
were worked out in a systematic and original manner, and
incidentally contain results of permanent value.

Three years after Roscoe's appointment in Manchester,
Robert Bellamy Clifton was elected to the Chair of Natural
Philosophy, but resigned in 1865 to take the Chair of Experi-
mental Physics at Oxford. His successor, William Jack,
subsequently Professor of Mathematics at Glasgow, was
interested mainly in the theoretical side of the subject, and *
resigned in 1870. It fell to his successor, Balfour Stewart,
to organize the department as an effective home of research,

1 Obituary Notice of Osborne Reynolds, " Proc. Roy. Soc.,"
Vol. LXXXVIIL, p. xvi (1913).

152 Britain's Heritage of Science

and to take the first step in that direction by fitting up a
laboratory, and encouraging students to submit themselves
to a training in accurate scientific measurements.

Balfour Stewart was brought up for a commercial career,
and went out to Australia as a man of business. But his
scientific ambitions, inspired as a student at Edinburgh
University, soon made him return to that University, where
he became assistant to David Forbes. Between 1859 and
1870 Stewart acted as Director of the Kew Observatory,
and devoted his energies mainly to investigations on
Terrestrial Magnetism. Chiefly interested in the connexion
between Terrestrial Magnetism and cosmical phenomena
such as the periodicity of sunspots, he did not, in the opinion
of some influential members of the Gassiot Committee of the
Royal Society, which controlled the work of the Observatory,
pay sufficient attention to the routine of observations. Some
friction resulted, and the vacancy in the Professorship at
Manchester gave him the welcome opportunity of changing
over to a more congenial position. Unfortunately, a few
weeks after he had delivered his first lecture, he met with
a serious injury in one of the most terrible railway accidents
that have taken place in this country. After an interval of
a year, he recovered sufficiently to take up his work again,
and though at the age of forty-three his accident had left
him with the appearance of an old man, his mind remained
he-h and young. During the time in which Balfour Stewart
presided over the Physical Department at Manchester, he
counted among his pupils several men who subsequently
rose to eminence — among them John Poynting and Sir
Joseph Thomson. His own work at that time was chiefly
statistical, dealing with the periodicities of meteorological
and cosmical phenomena.

Balfour Stewart's first and most important work on the
radiation of heat is much interwoven with the early history
of Spectrum Analysis, and affords the opportunity of giving
a brief account of that subject, especially as both in what
may be called the period of incubation and in its later
developments this country took a most important share.

As early as 1752, one Thomas Melville, about whose
history nothing seems to be known, experimented with

Balfour Stewart 153

coloured flames, and noted the yellow colour imparted to a
flame by soda. His observations were published in a book
bearing the title " Physical and Literary Essays." Exactly
fifty years later, William Hyde Wollaston, who has already
been mentioned as th§ discoverer of palladium and rhodium,
examined the blue light at the base of a candle flame through
a prism, and described the bright bands which appear in its
spectrum. Young repeated the experiments, and committed
what is perhaps the one great error of his scientific work,
when he ascribed the colours seen to effects of diffraction.
In these and most of the subsequent observations, the light
to be examined is passed through a slit, and traversing a
prism is separated into its components. The eye focussing
on the slit, with or without lenses, sees it illuminated by
the various elementary vibrations which the original light
may emit. These vibrations show themselves, therefore, as
luminous lines, which are images of the slit. The whole
appearance is called a spectrum, of which it is customary to
speak as consisting of " lines," a misleading term, because it
implies that the " line " is a characteristic of the substance,
while it is only an incident of the instrument by which the
spectrum is examined. The expression, having been univer-
sally adopted, may be retained with the understanding that
it is the position of the line which indicates the nature of the
light vibration, and therefore characterizes the luminous body.
Sir John Herschel investigated coloured flames in 1823, and
made two significant observations : " The colours thus
communicated by the different gases to flame afford, in
many cases, a ready and neat way of detecting extremely
minute quantities of them," and " no doubt these tints
arise from the molecules of the colouring matter reduced to
vapour, and held in a state of violent motion." Fox Talbot
in 1826 looked at the red lights occasionally used to illuminate
the stage in theatres. He correctly ascribed a red line to
nitre, but believed the yellow sodium line to be due to sulphur
or water. Eight years later Talbot returned to the subject,
and clearly pointed out that " optical analysis can distinguish
the minutest portions of these substances (lithium and
strontium) from each other with as much certainty, if not
more, than any other known method." He also offered the

154 Britain's Heritage of Science

remark that " heat throws the molecules of lime into such
a state of such rapid vibration that they become capable of
influencing the surrounding setherial medium and producing
in it the undulations of light."

In 1845 William Allen Miller (1817-1870), Professor of
Chemistry at King's College, London, published some observa-
tions on flame spectra, which were not very accurate, and
his plates left it doubtful whether the bright bands or the
dark intervals between them ought to be looked upon as
the essential feature. This seems to have been one of the
stumbling-blocks of early investigators when comparing the
continuous spectra of ordinary flames with the discontinuous
spectra of incandescent substances.

An important contribution to the subject was made by
William Swan (1818-1894), who, between 1859 and 1880, held
the Professorship of Natural Philosophy at St. Andrew's.
Swan was the first to introduce (1847) the collimator into
spectroscopic observations, and in 1857 he examined and
accurately mapped the spectrum of hydrocarbon flames. He
discussed the origin of the ubiquitous yellow line and came
to the correct conclusion that it is due to the presence of
minute quantities of sodium.

The spectra of the electric sparks passing between poles
of different metals were first examined by Sir Charles
Wheatstone, and described in a communication to the British
Association in 1835. Unfortunately an abstract only was
published, but even the short account given ought to have
drawn attention to the extreme importance of the matter.
The spectrum of mercury was observed and accurately de-
scribed, and proved to be identical, whether the spark be taken
in air, oxygen gas, the vacuum obtained by an air pump, or
the Torricellian vacuum. From these observations the correct
inference was drawn that the spectrum is the result of the
volatilization and ignition (not combustion) of the ponderable
matter contained in the spark. The spectra of zinc, cadmium,
bismuth and lead were also obtained by taking the sparks
from poles of the melted metals. The paper was published
in full in the Chemical News in 1861, and was then found
to contain this significant passage : " the number, position,
and colour of these lines differ in each of the metals

Spectrum Analysis 155

employed. These differences are so obvious that any one
metal may be instantly distinguished from the others by the
appearance of its spark, and we have here a mode of dis-
criminating metallic bodies more ready even than chemical
examination, and which may be hereafter employed for
useful purposes." Wheatstone himself fully realized the im-
portance of the subject, as is shown by his remark that " the
peculiar effects produced by electrical action on different
metals depend, no doubt, on molecular structure, and con-
tain hence a new optical means of examining the internal
mechanism of matter."

So much for what was known of the emission spectra of
luminous bodies before the date of Kirchhoff and Bunsen's
work; let us now turn to the phenomena of absorption.
Wollaston was the first who mentioned the dark lines which
traverse the spectrum of solar light, but he seems to have
looked upon them mainly as lines separating the different
colours, though he points out two of them that were not.
During the researches which Fraunhofer, the famous
optical instrument maker of Munich, conducted with a view
to improving the methods of determining the refractive
indices of different kinds of glass, sunlight was examined,
and found to contain many fine dark lines in its spectrum ;
these are now called " Fraunhofer lines." A large number
of them were carefully mapped, and the most prominent
served him as standards for his measurements; but he
examined also the light of a luminous flame and that of
some of the stars and planets. The first experiments date
back to 1814; nine years later he returned to the subject
and measured the wave-lengths of the principal lines by
means of his gratings. He pointed out that by using a blow-
pipe he could obtain a flame which emits a close doublet
of yellow light coincident with the solar lines D. Fraunhofer
examined the spectrum of the " electric light," and noticed
bright lines; he used the spark of an electric machine as
source of illumination and apparently took what we now
know to be the spectrum of air as characteristic of the electric
source of illumination. Of greater importance are his
observations on the spectra of the stars and planets, which
allowed him to recognize that the planets, like the moon,

156 Britain's Heritage of Science

have a spectrum identical with that of the sun, but that
some of the stars, like Sirius, show only a few very strong
lines. Sir David Brewster in 1834 compared the solar
spectrum observed by him with Fraunhofer's drawings, and
noticing additional lines which change with the position
of the sun, ascribed them correctly to effects produced in
our own atmosphere. He had already in 1832 referred with
approval to Herschel's suggestion that the dark Fraunhofer
lines were produced by absorption in the atmosphere of the
celestial bodies. An interesting observation which ought
to have attracted attention at the time, but, like many
others, was only saved from oblivion when the method of
spectrum analysis had been permanently established, was
made in France by Foucault. In the spectrum of the voltaic
arc, he noticed the presence of what we now know to be the
sodium lines, and identified them with Fraunhofer's line D.
He found further that on passing the sunlight through the
arc, these lines became darker, and further discovered that
the lines under certain conditions may be reversed hi the
arc itself.

In all these observations many important facts were
recorded, but the ideas on radiation were vague at the time
and no effort was made to connect it with absorption. Stokes;
in his own mind, seems to have been clear on the matter, and
in private conversation with Lord Kelvin " explained the
connexion of the dark and bright line (of sodium) by the
analogy of a set of piano strings tuned to the same note,
which if struck would give out that note, and also would be
ready to sound it, to take it up, in fact, if it were sounded
in air. This would imply absorption of the aerial vibrations,
as otherwise there would be creation of energy."1 At this
stage historically, but in ignorance of much of what has
been described, Balfour Stewart undertook a comprehensive
investigation of the subject of radiation and absorption.
Adopting Preevost's views that equilibrium of temperature
means a balance between absorption and radiation, he

1 The quotation is from a letter addressed by Stokes to Sir J.
Lubbock (afterwards Lord Avebury) ; see G. G. Stokes, " Memoir and
Correspondence," by Sir J. Larmor, Vol. II., p. 75.

Spectrum Analysis 157

applied for the first time the ideas of the principle of con-
servation of energy to the subject, by considering an enclosure
impermeable to heat radiations and at a uniform temperature.
This led him to the conclusion that the internal radiation
must everywhere be the same and only depend on temperature.
The rest follows easily : absorption and radiation must bear
a constant relation to each other in such an enclosure. He
illustrated the results by many striking experiments.

Much has been written about the relative merits of
several observers who anticipated, in various directions, the
great work of Kirchhoff and Bunsen. But the history of
science should not aim at assigning marks of merit to
different investigators. What interests us is how a great
generalization gradually matures, how it begins frequently
with the observation of isolated facts, generally overlooked
at first because their importance is not recognized. It may
be that some link between the disconnected observations is
wanting; it may be that experiment has gone ahead of
theory or theory may be waiting to be confirmed by ex-
periment. When the time is ripe, someone with a better
appreciation of the significance of the facts or a deeper
insight into their mutual connexion touches the matter
with a master hand, and presents it hi a form which carries
conviction. Though he may have worked in ignorance of
what has been done before, he has worked in an atmosphere
in which previous ideas and tendencies of thought have
been absorbed, and in general he owes something to the
pioneers who have gone before him. In some cases the
succession of events which lead to a discovery may be
compared to what would happen if a delicate balance carried
on one side the arguments in favour of a new idea, and
on the other hand the objections which are brought against
it. At first the side that bears the objections is much the
heaviest; as time goes on the difference becomes less
marked, sometimes by the removal of objections, but more
frequently by increased evidence in favour of the new idea.
Ultimately when sufficient weight is put on that side, a point
is reached when the balance tips over. This is the psycho-
logical moment when the discovery is accepted, and he
who adds the last grain is technically the discoverer. Those

158 Britain's Heritage of Science

who started loading the scale are then forgotten, unless
someone with a taste for historical continuity happens to
come across the record of their work. Especially when some
national feeling is involved, discussions on priority may then
be raised, and continued interminably, because there will
always be a conflict between those who attach importance
to the intrinsic merit of an investigation and those who
look only on the actual influence it has had on scientific
thought. In the strict administration of historical justice,
oral expressions of opinion like that of Stokes are not
admitted as evidence; he himself disclaimed any share in
the discovery of spectrum analysis. But as a testimony
that the analogy of sound can be applied to the radiations
of light and heat, it was a distinct step, and a well ascer-
tained and clear pronouncement such as that which passed
between Stokes and Kelvin deserves to be placed on record,
without detracting from the merit of others.

In order to appreciate correctly Balfour Stewart's work
the following consideration is important. If the foundation
of spectrum analysis be made to depend on such laws of
radiation as can be derived from the consideration of what
happens inside an enclosure of uniform temperature, his
priority is well established. He undoubtedly was the first
to realize the significance of studying the equilibrium of
heat inside such enclosures, and led the way in a direction
of research which has proved to be of capital importance
in the theory of radiation. But as regards their practical
bearing on spectrum analysis, too much weight has been
given to theoretical considerations founded on thermal
equilibrium. In all spectroscopic observations, the loss or
gain of heat is the essential factor. The step which takes
us from the uniform enclosure to the radiation and absorp-
tion when there is no equilibrium is not so simple as has
generally been assumed, and it is safer to accept spectrum
analysis as being mainly founded on experiment together
with such plausible theoretical analogies between sound and
light as were pointed out by Stokes. In this respect, the
work of Herschel, Talbot, Wheatstone, and Swan is of
greater importance in the history of spectrum analysis than
the theoretical work of Balfour Stewart, who, however, also

Spectrum Analysis 159

illustrated his views by striking experiments on the relation
between radiation and absorption. Incidentally, he corrected
a wrong idea based on erroneous experiments by a Dr. Bache
in the United States, who claimed to have shown that, while
the surface colour greatly affected the absorption, it had no
effect on the radiation of a body.

Bearing in mind what has been said, it is not surprising
that, notwithstanding all that had been done before their time,
Kirchhoff's and Bunsen's work created a deep impression.
The combination of a physicist and chemist was almost
necessary to bring out the full significance of the observations ;
and the accumulated experimental evidence furnished by
them was complete in itself, and left no doubt as to the
value of the new method of investigation, which formed not
only a most delicate test of the chemical nature of substances
which we handle in the laboratory, but would also be applied
to the analysis of any light-emitting body however great
its distance might be. It is well known how the spectroscope
at once revealed a number of new metals, among them being
thallium, which was first identified by Sir William Crookes.

The further development of the subject disclosed a far
greater potentiality of the spectroscopic attack than was
dreamed of by its originators. At first it was considered
that the spectrum was an atomic property ; in other words,
that each atom preserved its spectrum when combined
with other elements, so long at any rate as the substance
remained in the gaseous state. There was not much oppo-
sition to the next step, by which compounds were shown
to have independent spectra, but when it appeared that
even one and the same element could give a number of
different spectra under different conditions, fresh fields of
investigation were opened out. In the further elucidation
of the subject, this country has helped as much as, and
perhaps more than, any other. It will be sufficient to mention
the work of Lockyer, Liveing and Dewar, and the investi-
gations of Lord Rayleigh on the Optics of the Spectroscope,
which, by pointing out the limits of their power for given
optical appliances, have shown the direction in which an
extension of these limits is possible. In the investigation of
the absorption spectra of organic compounds a prominent

160 Britain's Heritage of Science

place must be given to Sir William Abney and Walter Noel
Hartley (1846-1913).

The success of Manchester in establishing great research
schools encouraged other cities to introduce university
teaching into great manufacturing centres. But Man-
chester had a start of over twenty years, and its record is
necessarily greater for that reason alone. Nevertheless, some
of the younger universities soon attracted men of eminence,
and of these, two stand out prominently, Arthur Riicker
(1848-1915) and John Poynting (1852-1914), the first Pro-
fessors of Physics at Leeds and Birmingham respectively.

Although Riicker was only connected with Leeds Univer-
sity during eleven years, much of his scientific work origi-
nated during that time ; and notably his researches on thin
films, carried on jointly with Professor Reinold. From the
colours of soap bubbles or of similar films their thickness
may be calculated, but as they thin out, the colour effects
disappear, and the film is black by reflected light. This
means that its thickness is less than the wave-length of
light and can not be measured by the simple optical method.
In order to investigate the molecular phenomena which
ultimately lead to the breaking of the film, Reinold and
Riicker undertook the extremely difficult task of measuring
the thicknesses of films when they are too thin for the
colour test to be applied. Their first method consisted in
determining the electric resistance of the films, the second
in increasing the number of films, until their aggregate
thickness became as great as the wave-length of light.
Both methods led to the same results, and some delicate
points in the subject of Molecular Physics were cleared up
by the investigation.

It is not possible here to enter more fully into other
important researches of Riicker, which included the two great
magnetic surveys of the United Kingdom, carried out in
association with his friend, Sir Edward Thorpe. Riicker
was an organizer and administrator of the highest ability,
and left the mark of his activity on all the institutions with
which he was connected. In 1886 he was appointed Pro-
fessor of Physics at the Normal College of Science in London,
and in 1896 elected Secretary of the Royal Society; both

James Prescott Joule

Arthur Riicker, John Poynting 161

positions he gave up when he accepted the Principalship
of London University in 1901.

John Poynting was the first Professor of Physics at
Mason College (now the University), Birmingham. He was
brought up in Manchester, and obtained his first instruction
in Physics from Balfour Stewart. In due course he went
to Cambridge, graduated as third wrangler, and was elected
to a Fellowship at Trinity College in 1878. For a time he
worked in the Cavendish Laboratory, and in 1880 went to
Birmingham, where he remained until his death. Poynting
belonged to the rare type of men who are more critical of their
own work than of that produced by others. The number
of his papers is therefore comparatively small, but each
of them marks some definite and generally important step.
He broke new ground when he investigated the path along
which energy may be considered to be propagated in an
electromagnetic field, and the vector, by means of which he
represented the magnitude and direction of the transmitted
energy, has proved to be a fruitful conception. His in-
vestigations on the " pressure of light " have also led to
many interesting consequences, which are likely to gain
considerable importance in questions connected with the
constitution of the sun and stars. In another series of
experiments he attacked the difficult problem of gravitational
attraction and showed how an apparently unpromising
method may be skilfully applied so as to give valuable
results.

Turning to the share of non-academic workers in the
recent progress of science, it is not surprising that it tends to
become less prominent, various reasons combining to render
it more and more difficult for the so-called amateurs to hold
their own. It is now generally only in those subjects which,
in consequence of great specialization, have become almost
entirely self-contained, that a man who is unable to devote
his whole time to study can hope to produce original work
of high quality. The most effectual of the contributing
causes has, however, probably been the growth of the
universities and their emancipation from the narrow ideas
of the Middle Ages. There is a university within the reach
of nearly everyone and men are drawn into the academic

L

162 Britain's Heritage of Science

profession who previously would have had to pursue their
science in solitude. But when all is said, much valuable
work is still being done, and was to an even greater extent
being done last century, by men who can only spare their
leisure to the pursuit of science. The work of the most
prominent of them may be briefly summarized.

Francis Baily (1774-1844), the third son of a banker. at
Newbury, may serve as an example of a man who, without
exceptional abilities, exerted a great and beneficial influence
on the science of his time by perseverance, organizing power,
and an unselfish devotion to its interests. After a long and
adventurous journey to America, on which he spent three
years of his early life, he engaged in commercial pursuits.
While he was earning a considerable fortune, he found time
to write an important work on the " Doctrine of Interest
and Annuities analytically investigated and expounded," and
a similar book on the " Doctrine of Life Annuities and
Assurances." Through an acquaintance with the chemist
Priestley, he had developed a taste for experimental enquiry,
and later he became interested in astronomy, to which
subject he devoted himself entirely after his retirement from
business in 1825. He was one of the founders of the Royal
Astronomical Society, and acted as its secretary during the
first three years of its existence. He did not himself observe,
but his critical and historical work proved to be of great
value. The publication of serviceable star catalogues, first
for the Astronomical Society and then for the British
Association, is mainly due to his zeal. His experimental
work included the investigation of the effects of air resistance
on the time of swing of a pendulum, and a repetition of the
Michell-Cavendish experiment on gravitational attraction.

John Peter Gassiot (1797-1877), originally a wine
merchant, was the first who systematically studied the
luminosity observed when an electric discharge passes
through gases at low pressure. The glass tubes with metal
electrodes which he had constructed for the purpose soon
came into common use under the name of Geissler tubes.
Gassiot was not only a successful experimenter, but also
a benefactor who used his wealth in encouraging and pro-
moting science. His gift of £10,000 to the Royal Society,

Baily, Gassiot, Grove, Schunck 163

to be devoted to the carrying out of magnetical and
meteorological observations with self-recording instruments,
has proved to be of special value.

Lord Justice Grove (1811—1896), while actively engaged
in practice at the Bar, found time to invent the electric
battery which goes by his name, and was, before the days
of electrodynamos, the most convenient appliance for the
production of large currents. Many of his electrical and
chemical experiments were of value, and his book on the
correlation of physical forces gives proof of a wide outlook
in science.

William Spottiswoode (1825-1883), the head of the
well-known printing firm, was at the same time an eminent
mathematician, and his scientific attainments were sufficiently
distinguished to justify his election to the Presidency of the
Royal Society, an office which he held at the time of his
death.

Edward Schunck was the typical man of independent
means who unselfishly devotes his whole time and wealth
to the pursuit of knowledge. He was born in Manchester
in 1820, his father having founded an important business
in that city. He studied chemistry in Germany, and shortly
after his return to England, settled down to research work
mainly connected with the colouring matter derived from
plants. Alizarin, the colouring substance of madder,
attracted his first attention, and his investigations prepared
the way for its subsequent artificial production.

He also made important additions to our knowledge
of the chemical composition of indigo and chlorophyll.
His laboratory, containing a finely ornamented room used
as a library, was beautifully fitted out for purposes of
research. Its contents were left to Owens College by his
will, and ultimately the laboratory was taken down and
re-erected as an annexe to the Chemical Laboratories of the
Manchester University, where it is now entirely devoted
to research work.

Henry Clifton Sorby (1826-1909) was another of the
busy men of so-called leisure who devote their lives to the
pursuit of science. His instrument was the microscope, and
he began investigating the minute structures of minerals

L 2

164 Britain's Heritage of Science

with a view to elucidating problems of geology. By studying
sections of rocks he laid the foundation of modern petro-
graphy and, devising methods for the examination of metal
surfaces, he originated a new era in the science of metal-
lurgy. He became interested in metals because he wanted
to examine the structure of meteorites. Not being able to
cut sections sufficiently thin to be transparent, he applied
acid to the polished surfaces, which then showed patterns
indicating the manner in which the crystallized parts of
the body hang together. The same method applied to ordi-
nary metals, and more especially to steel, has led to results
of far-reaching importance in practical engineering.

It is difficult to assign a correct position in the history
of science to a man whose work is entirely neglected and
buried, to be brought to light only when its novelty has
disappeared. Such a man has had no influence in shaping
scientific thought, yet his merits are as great as if his
discoveries had been acknowledged at the time. John
Waterston (1811-1884) probably furnishes the most con-
spicuous example of a long-continued neglect of work
which would have marked a great advance in knowledge,
had it been recognized at the time of its maturity. A paper
which contains results of the highest value in the theory
of gases was presented to the Royal Society, but only a
short and insufficient abstract was printed. In the words
of Lord Rayleigh : " the omission to publish it at the time
was a misfortune which probably retarded the development
of the subject by fifteen years." In the complete investi-
gation discovered in the archives of the Royal Society by
Lord Rayleigh and published in the Philosophical Trans-
actions fifty years after it had been communicated, it is
shown how the kinetic theory can explain in a simple
manner the physical behaviour of perfect gases. It is proved
that the kinetic energy of a molecule is a measure of its
temperature, whatever the nature of the gas, and it contains
the discovery — though imperfectly demonstrated — that " in
mixed media the mean square molecular velocity is inversely
proportional to the specific weight of the molecules." The
ratio of the specific heats of constant pressure and volume
is calculated for molecules exhibiting internal motions, only

H. C. Sorby, J. Waterston, G. Airy 165

a slip of calculation preventing the correct result being
obtained.

Of Waterston's life very little is known. He was born
in Edinburgh in 1811, and showed great aptitude for mathe-
matics while at the High School of that town. He then
became Naval Instructor in the service of the East India
Company. After his retirement he lived in various towns
of Scotland, and finally at Edinburgh. One evening in the
spring of 1884, he left his lodgings for his evening walk, and
was never seen again. It is supposed that he went to Leith
to look at a new breakwater which was being constructed
there, and that he accidentally fell into the water and was
swept away by the tide ; but this rests on surmise only.

Among professional British astronomers during the last
century four men stand out prominently : Sir George Airy,
Sir John Herschel, John Crouch Adams, and Sir David Gill.
When Airy was called to take charge, first of the Observatory
of Cambridge and later of the Royal Observatory at Greenwich,
he had already made his name famous by his mathematical
and optical investigations, which have been mentioned in
connexion with his career at Cambridge. In astronomy he
proved himself to be equally eminent as an administrator and
investigator. He introduced revolutionary reforms in the
practice of observatories by insisting on a rapid reduction
and publication of all observations. After his appointment as
Astronomer Royal, he set to work at once to reduce the series
of observations of planets which had accumulated during
eighty years without any use having been made of them.
This was followed up by a similar reduction of 8,000 lunar
observations. He was equally energetic in adding to the
instrumental equipment. When Greenwich was first founded,
the longitude determination at sea depended to a great extent
on measuring the distance between stars and the moon. Hence
accurate tables of the position of the moon were essential, and
the preparation of these tables has always been considered
to be the chief care of Greenwich. The observations were made
with a transit telescope which could only be used when the
moon was passing the meridian, until Airy in 1843 persuaded
the Board of Visitors to take steps for constructing a new
instrument which would enable him to observe the moon

166 Britain's Heritage of Science

in any position. In 1847 this instrument was at work, and
other important additions to the equipment were made as
occasion arose. Airy also originated the automatic system
by which the Greenwich time signals are transmitted each
day throughout the country. Among his theoretical investi-
gations in pure astronomy, one of the most important resulted
in the discovery of a new inequality in the motions of Venus
and the earth due to their mutual attraction, and this led to
an improvement in the solar tables.

Sir John Herschel (1792-1871) was the only son of the
great astronomer whose work was considered in a previous
chapter. After graduating as senior wrangler in 1813, he
joined a number of friends in their efforts to reform the
teaching of mathematics at Cambridge. The astronomical
problems which had occupied the later years of Sir William's
life then attracted the son, who, after his father's death,
completed the work on double stars, and published an
important memoir on their orbits.

In 1833 he embarked for the Cape, in order to extend to
the southern hemisphere the general survey of the heavens
which his father had carried out in the northern sky. It
was to a great extent a spirit of loyalty to his father which
kept him to the subject of astronomy, for his own bent of
mind drew him more towards physics and chemistry. He
discovered the solvent power of hyposulphite of soda on
otherwise insoluble salts of silver, a property which later
proved so useful in photography. As a writer he was clear
and effective. His article on " Light " in the Encyclopaedia
Metropolitana forms an excellent record of what was known
at the time, and his " Outlines of Astronomy " may still
serve as a useful book of reference.

The work of Adams has already been described in a
previous chapter (p. 125).

David Gill (1843-1914), after a period of study at the
University of Aberdeen, entered his father's business,
which consisted in the making of clocks. But his interest
in science, stimulated by the influence of Clerk Maxwell,
who for a time held a Professorship at Marischall College,
soon asserted itself, and he established a physical and chemical
laboratory in his father's house Turning his attention to

Sir John Herschel, Sir David Gill 167

astronomy, he became acquainted with, and ultimately
engaged as private assistant by, Lord Lindsay, an enthusiastic
amateur astronomer, then about to erect a private observatory
at Dunecht. He accompanied Lord Lindsay in his expedition
to Mauritius, undertaken for the purpose of observing the
transit of Venus in 1874. This rare event, as previously
explained in connexion with its first observation by J.
Horrocks, serves to determine the distance between the
earth and the sun, but alternative methods promising more
accurate results had already been suggested. The relative
distances of the different planets from the sun being known
by their times of revolution, we may substitute the measure-
ment of the distance of any one planet which is in a suitable
position for the direct determination of the solar distance.
Certain planets occasionally approach the earth sufficiently
near to apply this method. As the earth turns round its
axis, the observer's point of view is sufficiently altered
between a morning and evening observation to show a
measurable shift in the position of a planet as compared
with that of the surrounding stars. While at Mauritius
Gill found that one of the minor planets, Juno, happened
to be suitably placed to test the method, and he obtained
most encouraging results. A good opportunity of pursuing
the investigation presented itself in 1877, when the situ-
ation of the planet Mars was exceptionally favourable for
the purpose. Gill left the service of Lord Lindsay and
established himself on the island of Ascension. Though the
results obtained were good, Gill confirmed his conclusion
that the minor planets were better suited for accurate
measurements. He returned to the subject ten years later,
and a combination of observations of three minor planets,
made partly by Gill at the Cape and partly by other astronomers
whom he had interested in the work, has given us the best
determination of the solar parallax we possess.

In 1879 Gill was appointed Astronomer Royal at the
Cape, and he directed the work of the observatory with
distinguished success until 1906. Unbounded perseverance,
unrivalled skill in observing, and an exceptional mechanical
knowledge which served him in the design of instruments
were combined in his person to a rare degree. A favourite

168 Britain's Heritage of Science

instrument of his, the potentialities of which for accurate
measurements he was the first to recognize, was the helio-
meter, the essential par of which consists of an object-glass
divided into two halves, which could be made to slide along
the dividing line. If the image of a star formed by one half
be brought into coincidence with the image of a neigh-
bouring star formed by the other half, the angular distance
between the stars is indicated by a suitable measuring
arrangement. With a telescope of this construction Gill
instituted a series of observations for the determination of
stellar parallaxes, which raised the subject up to a higher
plane. Another important research carried out by Gill with
the assistance of others was the determination of the mass of
Jupiter by observations of his satellites.

Gill was not only an eminent investigator; large ideas
originated in his mind, and were pushed forward with
unlimited energy. He originated the great international
enterprise for cataloguing and charting the whole sky by
photography. He also successfully advocated an accurate
trigonometrical survey of the whole of South Africa, and
formed a scheme for the measurement of an arc of meridian
which should run along the thirtieth meridian east of Green-
wich through the whole length of Africa to the mouth of the
Nile, and connect by triangulation through the Levant with
the Roumanian and Russian arcs. He secured the assistance
of Mr. Cecil Rhodes, and the work, though frequently inter-
rupted, partly through the political troubles in Africa and
partly through want of money, was proceeding slowly when
stopped by the outbreak of the present war.

Gill's scientific activity was continued after his return to
England, and during the last years of his life he endeavoured
to stimulate the manufacture of optical glass in this country.
His efforts deserved a better response than they received
and though they were primarily directed towards securing
the large blocks required for telescopes, the whole question
of glass manufacture, which has since become of such pressing
importance, was involved. By his death British science lost
an intensive driving force.

While professional astronomers carried on their excellent
researches the great improvements in the construction of

D. Gill, Lord Hosse, W. de la Rue 169

reflecting telescopes during the nineteenth century was
entirely the work of amateurs. William Parsons, third Earl
of Rosse (1800-1867), took the first step in 1827. As William
Herschel had never published his methods, there was no
established procedure to shape concave mirrors. Lord Rosse
had to start from the beginning, and to invent the machine
for grinding and polishing the speculum metal to the required
shape. After a number of attempts he was eminently
successful, and in 1845 completed a mirror six feet hi dia-
meter with a focal length of nearly sixty feet. The structure
necessary to hold and move such a gigantic telescope pre-
sented considerable engineering difficulties, but these were
overcome, with the result that Lord Rosse was soon able
to announce a number of important discoveries. Many
luminosities that had been classed as nebulae were found to
consist of closely packed star clusters. Others remained
unresolved, and among them the interesting family of spiral
nebulae was recorded. Further improvements in the methods
of shaping and polishing mirrors are due to William Lassell
(1799-1880) and James Nasmyth (1808-1890). The former,
a Lancashire brewer, had already, in 1820, constructed a
small telescope with his own hands, being too poor to
purchase one. Later he improved on Lord Rosse 's methods,
and with a larger instrument discovered two new satellites
of Uranus, a satellite of Neptune, and an eighth satellite of
Saturn. James Nasmyth, chiefly known as the inventor of
the steam hammer, was also much interested in astronomy.
The sharpness of his vision and quality of his instrument
is shown by his observations of the granular structure of the
solar surface which no one had noticed before him.

Warren de la Rue (1815-1889), a member of the well-
known printing firm, was a generous supporter of many
scientific enterprises. In early life he had made further
improvements in the process of shaping concave mirrors,
and successfully constructed a reflecting telescope. He was
the first to appreciate the opportunities offered to astronomers
by the invention of photography, and in 1860 fitted out an
expedition to observe a total eclipse in Spain. The slow
acting plates of the time were not sufficiently sensitive to
show the solar corona which appears during an eclipse, but

170 Britain's Heritage of Science

the red flames shooting out from the edge of the sun were
clearly shown in his photographs. This was an important
achievement, as there had been some doubt whether these
so-called protuberances were real phenomena belonging to
the sun. De la Rue also introduced the daily photographic
record of the sun, originally carried out at Kew, and now
at Greenwich and other places in the British Empire.

So far all concave mirrors used in reflecting telescopes
had been made of speculum metal, an alloy of tin and
copper, which tarnishes in the course of time. A process of
polishing almost as troublesome as the original shaping of
the surface had then to be undertaken. It was, therefore,
a substantial step in advance when Andrew Ainslie Common
(1841-1903), an engineer by profession, introduced mirrors
made of glass silvered at the surface, for the silvering could
be renewed without interfering with the shape of the surface.
Common acquired great skill in grinding the surfaces of glass ;
one of his mirrors, three feet in diameter, is now at work at
the Lick Observatory, and a five-foot mirror forms part of
the equipment of Harvard. The photograph which Common
obtained of the nebulae in Orion first showed the complicated
structure of that wonderful object, and was described by
Sir William Abney as " epoch-making in astronomical
photography."

With the introduction of dry plates a new era began for
Astronomy, and one of the most persevering and successful
workers in the field was Isaac Roberts (1829-1904), whose
beautiful collection of photographs of celestial objects, and
notably of nebulae, form a permanent record which will in
the future prove of the greatest value. Roberts was a builder
by profession. In 1890, the year after his retirement from
business, he moved from Liverpool to Crowborough, in
Sussex, where the clear air allowed him to produce his
finest work.

Until the middle of last century the astronomer was
confined in his observations to the use of the telescope ; he
could determine the position of stars,investigate their displace-
ments in the sky, and examine the structure of star clusters
and nebulae. Beyond this he was unable to go, until the
invention of the spectroscope gave him the power to extend

A. Common, I. Roberts, J. N. Lockyer 171

his range in an unexpected direction. The history of science
can furnish no more striking instance of an almost unlimited
field of research suddenly opened out by a simple application
of a few laboratory experiments. The most successful of the
workers who utilized the great opportunities provided by
the new method of Spectrum Analysis were Sir Norman
Lockyer and Sir William Huggins. Lockyer's first great
achievement was the observation in broad daylight of the
prominences which up to that time could only be seen during
total solar eclipses. He proved that they mainly consisted
of glowing hydrogen. The merit of the discovery is in no way
diminished by its having almost simultaneously been made
by the French astronomer Janssen. Continuing his researches,
Lockyer established that the upper layer of the sun's atmo-
sphere, which reveals itself at the edge of the solar disc in
the form of a bright line spectrum, consisted mainly of the
lighter metals such as calcium and barium with hydrogen.
A bright yellow line was also universally present which
could not be identified as belonging to any known element.
Lockyer conjectured that it was due to an unknown gas
which he called helium; this gas, as will appear, was subse-
quently discovered on the earth, and is found to play a most
important part in modern physics. The identification of
terrestrial elements in the atmosphere of the sun or stars
ultimately proved not such a simple matter as was at first
supposed, because the relative intensities of the lines emitted
by a luminous body, and sometimes the whole spectrum,
changed when the conditions were altered. Lockyer turned
this complication to good account by trying to gauge not only
the substance itself, but its temperature and physical con-
dition in the celestial bodies. He was thus led to his meteoric
hypothesis of the formation and subsequent evolution of the
solar systems, into which it is not possible to enter here.

The most memorable discovery with which the name
of Huggins is connected is the measurement of the velocity
of stellar bodies in the line of sight. A body moving directly
towards, or away from, us keeps the same apparent position
in the sky, but just as the whistle of a locomotive alters its
pitch when, after approaching us, it passes and then moves
away, so is the wave of light received by us affected according

172 Britain's Heritage of Science

as a star is receding or approaching. Huggins showed how
this principle can be applied to stellar motion, and thus
laid the foundation of a branch of astronomy which is
continuously growing in importance. Previously Huggins
had, in conjunction with W. A. Miller, carefully mapped
some star spectra; he also had investigated the spectra of
nebulae, and found that some of them consisted of glowing
gases. In subsequent researches he found the luminosity of
comets' tails to be mainly due to carbon compounds. By
patient and painstaking work Huggins further developed
the methods of obtaining photographic records of stellar
spectra, and the important results obtained formed the
starting point for the many distinguished astronomers who
have since taken up the work.

Before leaving the subject of Astronomy reference must
be made to a notable advance in the construction of re-
fracting telescopes. During the middle of last century, the
largest lens made had a diameter of sixteen inches. At the
exhibition of 1862, Messrs. Chance, of Birmingham, exhibited
glass discs of crown and flint twenty-six inches in diameter,
and Mr. Robert Stirling Newall (1812-1889), of Gateshead,
induced Messrs. Cook, of York, to construct from these
discs an achromatic lens of twenty-five inches. This was
successfully accomplished, and the telescope is now doing
excellent work in the Astrophysical Observatory of Cam-
bridge. Larger instruments have been made since, but the
step from sixteen to twenty-five inches is one which deserves
a permanent record in the history of the subject.

Modern astronomy, like other branches of science, depends
so much on photography that a brief account of the history
of this interesting and fascinating art may be here introduced.

The darkening action of light on silver chloride was first
discovered and investigated by the Swedish chemist Scheele.
W. H. Wollaston had observed that the colour of the yellow
gum guaiacum was altered by the action of light, and Sir
Humphry Davy had noted a similar effect in the case
of moist oxide of lead. The first actual photographic print
was obtained in 1802 by Thomas Wedgwood (1771-1805),
who threw shadows on paper moistened with a solution of
silver nitrate, and obtained prints giving the outlines of the

W. Huggins, R. S. Newall, W. Abney 173

shadows, but his picture was evanescent, as he was unable
to fix it. Rudimentary as this procedure was, it contained
the germ of the future contact printing. Next came the
work of Daguerre and Niepce in France, resulting in the
well-known daguerreotype. In 1840 Sir John Herschel
introduced hyposulphite of soda as a fixing agent, and in
1841 Fox Talbot greatly improved Wedgwood's original
process, using silver iodide on paper sensitized by " gallo-
nitrate of silver." The introduction of collodion as a con-
venient vehicle holding the silver salts was first suggested
by G. le Gray, and put to practical use by Frederick Scott
Archer and P. W. Fry. In the subsequent development of
the dry plate important progress was due to R. Manners
Gordon, W. B. Bolton, and B. J. Sayce. The gelatine
emulsion process was used by R. L. Maddox in 1871 and by
J. King in 1873, but first introduced in a workable form by
R. Kennett in 1874. The merit of giving rapidity of action
to dry plates belongs to C. Bennett (1878). Further progress
was made by Colonel Stuart Wortley and by W. B. Bolton
in 1879.1

The modern theory of photography almost entirely
depends on the investigations of Sir William Abney. He
introduced scientific methods in the measurement of the
sensitiveness of plates, investigated the effects of tempera-
ture, and showed the important influence which the size of the
sensitive particles had on their behaviour in different parts
of the spectrum. He was thus able to obtain a silver bromide
sensitive to the red light, and was the first to photograph
the infra-red rays of the solar spectrum.

A f@w words should be said about the history of colour
photography. Lord Rayleigh pointed out in 1887 how
particles of silver might be deposited in layers half a wave-
length apart. A film containing such layers would have the
power of reflecting copiously that special kind of light which
had served to form it. This process was actually employed
to reproduce natural colour effects by M. Lippmann, of
Paris ; but it suffers from the disadvantage that the correct

1 For a fuller account of the history of photographic processes,
see the article on " Photography," by Sir Wm. Abney, in the
" Encyclopaedia Britannica," Xlth ed.

174 Britain's Heritage of Science

colours are given only when the light falls on the film at
the particular angle under which it was originally produced.
The process of Joly, introduced in 1897, is free from this
defect ; the principle on which it is based is the same as that
subsequently employed with great success by " A. Lumiere
et Fils," of Lyons, whose method of working, however,
differs materially from that of Joly.

Photography is looked upon by some as a pleasant
pastime, by others as an art. The chemical and physical
properties of matter which allow the rays of light to form
a latent picture, to be subsequently developed, fixed and
printed, are in themselves a fascinating study, and there is
no limit to the utility of photography as an aid hi scientific
investigations. Here, as elsewhere, science exerts its greatest
charm when it forms a connecting link between the ordinary
interests of our daily life and the abstract questions which
engage the attention of academic philosophers. Thus,
nearly all problems of geophysics have both an intensely
practical and a deeply theoretical side. The commonplace
necessity of defining the boundaries of land leads to the
demand for accurate maps, and this, again, opens out
investigations on the figure and size of the earth. One
question suggests another, until abstruse mathematical pro-
blems acquire a special interest owing to their connexion
with the history of the world's formation. Similarly, fore-
casts of weather that shall be helpful to the farmer demand
a study of aero -dynamics, involving mathematical treatment,
combined with experimental work of high precision, and
the ordinary phenomenon of the tides takes us inevitably to
problems demanding the genius of such men as Kelvin and
George Darwin.

The ordinary making of maps is a task belonging to the
Government services, and it is to officers in the Army and
the officials in charge of the various surveys at home, or in
the colonies, that we are mainly indebted for our knowledge
of geodesy. Such work, important as it is, often receives
insufficient acknowledgment because, being co-operative, the
share of each man cannot always be clearly defined. But a
few examples may be given.

Captain Henry Kater (1777-1835), the son of a sugar

Henry Kater, Edward Sabine 175

baker, entered the army and joined his regiment in Madras.
He had a taste for mathematics, and became assistant to
William Lambton, who was conducting a survey of the
Malabar and Coromandel coast. After his return to England
he took part in the British survey, and turned his attention
to the improvement of accurate geodetic and astronomical
measurements. Kater 's pendulum is an ingenious arrange-
ment for eliminating the errors due to an irregular distribu-
tion of mass in the ordinary pendulum when it is used for
gravity measurements. The determination of the difference
in longitude between Paris and Greenwich gave him further
opportunities for exercising his ingenuity in devising new
methods of observation. In 1827 Kater was elected
Treasurer of the Royal Society, and held that position
during three years.

General Sir Edward Sabine (1788-1883) organized world-
wide observations on gravity, and the elements of terrestrial
magnetism. The importance of his work calls for a short
account of his life. He was educated at the Woolwich
Military Academy, and received a commission in the Royal
Artillery at the age of fifteen. After seeing much active
service, he returned to England in 1816. Shortly afterwards
he was appointed astronomer to the Arctic Expedition which
sailed under Ross in search of the North-West Passage, and
after his return home took part in a second Arctic Expedition
under Edward Parry. In 1823 he undertook an extensive
journey to measure the value of the gravitational force at
different points of the earth's surface. In 1830 he was recalled
to active service, the condition of Ireland necessitating an
increased military establishment. He stayed in Ireland
until 1837, using part of his time to organize the first
magnetic survey of the British Isles. During his subsequent
life, which was entirely devoted to science, he was indefa-
tigable in getting magnetic observatories established in
many countries, and promoting further pendulum observa-
tions, more especially in India, where ever since they have
formed an important part of the Government Survey's
work. Sabine was Treasurer of the Royal Society from
1850 to 1861, and during the following ten years he filled
the position of President.

176 Britain's Heritage of Science

Most distinguished among the Directors of the British
Survey was Alexander Ross Clarke (1828-1914), who has
given us the most accurate determination so far obtained of
the size and figure of the earth. He was concerned in several
of the principal measurements of meridional arcs, and in
1860 was entrusted with the comparison of the national
standards of different countries, a most delicate piece of
work, which required the building of a separate room at the
Ordnance Survey Office.

Our account of the progress of Meteorology must be short
and incomplete, but we may recall William Charles Wells
(1757-1817), the London doctor who first gave the correct
explanation of the formation of dew, Luke Howard (1772-
1864), who classified the clouds, and John Apjohn (1796
-1880), who showed how to calculate the humidity of the
air from observations with the wet and dry bulb thermo-
meter. We must also remember the wonderful balloon ascents
of James Glaisher (1809-1903), who, reaching a height of
over 30,000 feet, obtained the first observation of the
upper air. A kite was used in meteorological work as early
as 1749 by Alexander Wilson, of Glasgow, and its modem
application dates from the experiments made in England
in 1882 by E. D. Archibald. One of the most enthusiastic
workers in Meteorology, Alexander Buchan (1829-1907),
studied at Edinburgh and was engaged for some time as a
school teacher, but in 1860 he was appointed secretary of
the Scottish Meteorological Society, and was henceforward
able to devote himself entirely to his favourite study. His
work on atmospheric circulation possesses considerable im-
portance, and he was also one of the chief promoters of the
observatory which, during a number of years, stood on the
summit of Ben Nevis.

A discovery of great value to meteorology was made by
John Aitken, of Falkirk, who in 1883 observed that water
vapour always requires some nucleus to condense upon.
The most common nuclei are the dust particles which are
always present in the atmosphere, and every drop of rain
or particle of fog contains some solid contamination at its
centre. The best protection against fog is, therefore, the
purification of the atmosphere. The condensation of water

A. Ross Clark, A. Buchan, G. H. Darwin 177

on solid matter has been utilized by Aitken in constructing a
little instrument which allows us to count the number of
particles of solid matter contained in the air. He found
that even the cleanest air will contain about 20 particles per
cubic centimetre, while in London or Paris the number
generally rises to well over 100,000.

The work of Sir George Howard Darwin (1845-1912)
may serve to illustrate how a geophysical problem which in
its main features is easily understood, is found to involve
the whole history of the Universe as soon as we pass from
the general explanation to the more detailed study required
to give accurate numerical results. That the tides of the
ocean are due to the gravitational attraction of the sun and
moon was known already to Newton, and it can be shown
without difficulty that the explanation agrees in a general
way with observations. But, if we wish to formulate a
mathematical theory, we must begin by simplifying the
problem, and assume the earth to be a rigid solid sphere
covered entirely by a layer of water having the same depth
everywhere. The statement of this problem is simple enough,
but its solution becomes already complicated when the com-
bined attractions of the sun and moon are considered. Yet
we are not anywhere near the real tides on the real earth.
The ocean does not cover the whole globe, it is not of
uniform depth, and the solid core of the earth is not
absolutely rigid, but appreciably yields to the disturbing
forces. When we try to take account of these complications,
even in the roughest manner, we see that there must be a
frictional effect tending to retard the rotation of the earth;
this involves a re-acting force on the moon, and it can be
shown that this must slowly drive it further away. Hence
we conclude that there must have been a time when the
moon was nearer, and the earth rotated more rapidly, and,
looking still further back, this brings us to the time when
the moon may have formed part of the earth and ultimately
separated from it. Can we form an approximate estimate of
that time ? Such are the questions which occupied George
Darwin during a considerable part of his life. The whole
problem does not, of course, affect the earth only, but
concerns every celestial body. It opens out the whole

If

178 Britain's Heritage of Science

question of the stability of fluid gravitating and rotating
bodies. George Darwin's own contributions to the subjeci
have materially helped to establish a scientific basis for th(
treatment of a subject, fundamental in cosmogony, whicl
has fascinated the most powerful mathematical brains ir
recent times. For his other important researches the readei
must be referred to his collected works, but some reference
may be made to the time which he ungrudgingly devotee
to assist all efforts which aimed at an organized co-ordi
nation of scientific work, and co-operation between differenl
scientific bodies. During thirty years he was a member oj
the Meteorological Council, and of the Treasury Committee
which superseded it. He actively supported international
scientific undertakings, and more especially the Internationa
Geodetic Association, on which he represented England foi
many years; in 1909 he was elected its President.

Several instances have already been given of the reci-
procal relation between utilitarian objects and abstract
scientific truth, and a further example is furnished by the
work of John Milne (1850-1913). After studying Geology
and Mineralogy at King's College and the Royal College ol
Mines, he gained some practical experience in the mines
of Cornwall and Lancashire, extending his knowledge fry
a course of study at Freiberg, and a visit to the mining
districts of Germany. In 1875 he was appointed Professor
of Geology and Mining at the Imperial College in Tokio,
where he was at once confronted with important practical
problems arising out of the frequent occurrence of earth-
quakes in Japan. In order to construct buildings and bridges
so that they should resist the movements of the foundations
on which they are built, it is necessary to study, in the
first instance the nature of these movements. Milne was
attracted by both the practical and theoretical side of the
investigation, but as no suitable instruments were available
for the purpose, he supplied the want, and for a number of
years his seismographs became the standard instruments.
Important questions immediately suggested themselves, and
Milne became the founder of a new science. After his return
to England, he organized, with the assistance of the British
Association, in different parts of the Empire and other

Sir George Darwin, John Milne 179

countries, a large number of suitable stations at which earth
tremors were accurately observed. The records of the obser-
vations, interpreted partly by Milne himself and partly by
other seismologists, proved to be of the highest interest.
The waves propagated through the earth from the centre
of a large disturbance are found to be noticeable with
delicate instruments all over the world. We now know that
the general movement spreads out from the centre of a
disturbance in three distinct waves, each propagated with its
own peculiar velocity. The first is a longitudinal wave, which
passes through the earth like a sound wave does through air.
The second is a transverse wave, arriving somewhat later;
both these waves reach us by transmission across the body
of the earth. A third set of waves, which in the records
appears as an oscillation of larger amplitude and longer
period than the rest, spreads over the surface of the earth
with a velocity of about 3*5 kilometres per second. The
interval between the arrival of these three types of waves
serves to indicate the distance of the centre of the dis-
turbance, and Prince Galitzin has shown how the direction
of the first impulse gives us the direction in which that
centre lies. Hence it is now possible to locate a distant
earthquake by means of observations taken at any one
place where it is still able to affect the delicate instruments
which, by a self-registering arrangement, are always ready
to record the waves.

The scientific interest of the subject lies in the information
it is likely to yield on the internal constitution of the earth ;
for some of the waves that reach us, if the centre of dis-
turbance be far away, have passed through deep regions,
approaching in some cases the actual centre of the earth.
The manner in which their path bends round owing to
changes in the elastic properties of the earth at different
depths is indicated by the direction and magnitude of the
oscillation which the wave impresses on our instruments.
It is difficult to interpret completely the observed effect,
but the investigation has already advanced sufficiently to
.how that important results may still be expected from that
jtudy of earth tremors which Milne initiated.

The survey of the history of British physical science has

M 2

180 Britain's Heritage of Science

now been brought to the period when men of the present time
were called upon to receive the heritage, and do their best
to hand it on to then* successors. The problems of to-day
may not be seen in their right perspective; yet the last
thirty years have been so exceptionally fertile in new dis-
coveries that we may anticipate with confidence the judg-
ment of posterity on those great advances which have
revealed an entirely new class of phenomena, and enabled
us to form views on the structure of matter which, at any
rate, may be considered to be an advance on our previous
knowledge. A very brief summary, however, must suffice.

In the seventies of last century it was generally thought
that our power to discover new experimental facts was
practically exhausted. Students were led to believe that
the main facts were all known, that the chance of any
new discovery being made by experiment was infinitely
small, and that, therefore, the work of the experimentalist
was confined to devising some means of decicling between
rival theories,- or by improved methods of measurement
finding some small residual effect, which might add a more
or less important detail to an accepted theory. Though it
was acknowledged that some future Newton might discover
some relation between gravitation and electrical or other
physical phenomena, there was a general consensus of opinion
that none but a mathematician of the highest order could
hope to attain any success in that direction. Some open-
minded men like Maxwell, Stokes, and Balfour Stewart,
would, no doubt, have expressed themselves more cautiously,
but there is no doubt that ambitious students all over
the world were warned off untrodden fields of research,
as if they contained nothing but forbidden, though perhaps,
tempting, fruit. When Crookes, in the year 1874, constructed
his radiometer, it looked for a short time as if he had
definitely disposed of such timid and discouraging opinions;
but, on the contrary, he seemed only to have confirmed
them. For the apparent repulsion of light observed in the
radiometer was found to be due to the residual gas in his
exhausted vessels, and could be explained by the then
accepted kinetic theory. He had, no doubt, by greatly
improved methods, discovered a new effect, but this had

Lord Rayleigh, Sir William Ramsay 181

only led to perfecting an established theory in an important
detail.

The new era begins with Lord Rayleigh 's discovery of
argon. The research which led to it was originally under-
taken with a view to testing the hypothesis of William Prout
(1786-1850), a London doctor, according to whom the atomic
weights of all chemical elements are exact multiples of that
of hydrogen. In the course of an accurate determination of
the density of nitrogen it was found that, when the gas is
prepared from air by removing all other known constituents,
it has a density half per cent, greater than when it is obtained
directly from ammonia. Rayleigh then drew the conclu-
sion that the discrepancy was due to some unknown body,
probably a new gas in the atmosphere heavier than nitro-
gen. While the research was advancing successfully, William
Ramsay joined the investigation, and the final results were
published by Rayleigh in conjunction with him.

Sir William Ramsay (1852-1916) then entered into that
period of his activity in which discoveries rapidly succeeded
each other. Sir Henry Miers drew his attention to a certain
mineral which was known to give out an inert gas when
dissolved in an acid. This gas was supposed to be nitrogen,
but Miers thought it might turn out to be argon. Ramsay
extracted the gas, examined it with a spectroscope, and to
his surprise found the bright yellow line which appears so
brilliantly in the light emitted all round the edge of the
sun and in its protuberances. The gas proved, therefore,
to be identical with the one spectroscopically discovered
many years previously by Sir Norman Lockyer, and named
by him " helium." Subsequently, by applying the process
called " fractional distillation " to liquid air, Ramsay could
isolate three additional elements : krypton, xenon, and
neon.

In the meantime, experiments on the discharge of
electricity through gases had made rapid progress. His
experiments with the radiometer had led Crookes to intro-
duce great improvements in the construction of the mercury
pumps used to obtain high vacua in glass vessels. By sending
electric currents of high potentials through such vessels,
Crookes investigated the vivid phosphorescent luminosity

182 Britain's Heritage of Science

which appears near the negative electrode. Important
results were obtained in these researches. Investigations by
other observers which cannot here be described, led to the
conclusion that gases, which ordinarily are insulators, could
in various ways be made to conduct electricity, and the
phenomena suggested that the conductivity was due to the
formation of carriers analogous to the ions which normally
exist in liquids. Gases, in fact, could be ionized. The
stage was now reached where experiments definitely pointed
to the conclusion that electricity, like water, had an atomic
constitution. To furnish the proof, it was necessary to
show that the atomic charge was the same in all cases. The
experiments with liquids gave no direct measure of this
charge, but they allowed us to determine its ratio to the
mass of the carrier. That carrier in liquids is the chemical
atom, and it was natural at first to suppose that the same
would be the case in gases ; if so, the matter could be tested,
as we know the relative masses of different chemical atoms.
The first experiments made in that direction led to no
decisive results, though they supplied a method which proved
useful. The question was finally solved by Sir Joseph
Thomson, who proved that the carrier of negative electricity
had a mass much smaller than that of a chemical atom;
ultimately it was found that, near the kathode of an electric
discharge through gases, it is actually the atom of negative
electricity which is set free, and acts as carrier.

Thomson further determined the charge of the electron,
the name given to the atom of electricity by Johnstone
Stoney (see p. 139), and found it to agree with that which
may indirectly be derived from the electrolysis of liquids.

There can be no doubt that Sir Joseph Thomson's ex-
periments will be looked upon in future as a landmark in
the advance of science as great as those that have been
described in our first chapter.

Thomson's discovery was announced at the British
Association meeting of 1899. Since then our ideas have
advanced rapidly, and we now consider corpuscles of positive
and negative electricity to be the elemental atoms from which
all matter is built up. In the origination and development
of this theory Sir Joseph Larmor has taken an active part.

Sir J. J. Thomson, Sir E. Rutherford 183

During the last few weeks of the year 1896 some remark-
able experiments of W. C. Roentgen revealed to us a new
and quite unexpected class of phenomena. The electric
discharges in a highly-exhausted vessel were found to be
capable of generating a radiation — now known to be due
to very short waves — which could penetrate many bodies
opaque to ordinary light. This was the X-radiation which
has proved to be of such enormous value in surgery. Their
investigation indirectly led to our knowledge of a still more
remarkable class of phenomena. The French physicist,
Becquerel, while trying to find whether the sun emitted
X-rays, observed a most surprising effect, which could only
be accounted for by assuming the existence of a new form
of radiation, essentially different from that of the X-rays.
Separating the substance that was mainly responsible for it,
M. and Mme. Curie discovered the new metal radium. This
is the typical radio-active element, but two other known
chemical elements — uranium and thorium — proved to resemble
radium in its peculiar properties. A new science then opened
out.

The effects of radio-activity show themselves by their
power of ionizing air and affecting photographic plates, but
the first results were extremely puzzling, and experimenters
were being led away on a wrong track when Sir Ernest
Rutherford took up the work. He first discovered that
thorium and radium gave up gases — the so-called emana-
tions— which themselves were radio-active. It was the
disturbing effect of these gases which, diffusing through
the air of the laboratory, had affected the instruments, and
led Becquerel and Curie astray; it had to be separated
from that of the parent substance before the different
phenomena could be disentangled. By a series of remarkable
experiments, Rutherford soon cleared up the essential features
of radio-activity. In conjunction with Frederick Soddy he
then developed his theory, which now stands on a firm
basis. Radio-activity was shown to be the result of the
ejection of corpuscles from the parent body, which thereby
became transformed into another substance which was
generally itself subject to further decomposition through the
emission of other corpuscles. The decomposition proceeds

184 Britain's Heritage of Science

at a perfectly definite rate, and the life of any radio-active
substance can, therefore, be foretold. The ejected particles
consist either of one or more negative electrons (/3 particles),
or positively charged corpuscles (a particles); frequently
both are emitted. The a particle carries twice the charge
of an electron, and weighs about twice as much as an
atom of hydrogen : that is to say, as much as a helium atom.
Rutherford formed the idea that the two might be identical
and this was experimentally confirmed by Sir William Ramsay.
The emanation of radium which emits an a particle in its
decay was introduced into, and kept in an exhausted tube for
several days, when it was found that the spectrum line of
helium could be clearly seen, though no helium had originally
been present. This experiment, which gave the proof of
Rutherford's surmise, was an historical event, as it supplied
the first definite example of the decomposition of a so-called
chemical element. For the emanation possesses all the
characteristics of such an element and was shown to decom-
pose spontaneously, helium being one of the products.
The subsequent development of radio-active experiments
and theories confirmed the original ideas, and many new
and interesting facts were brought to light.1 These must be
passed over, and we might here close our account, were it
not for the brilliant researches of a young man, who promised
to become one of the great investigators of his time.

Henry Moseley (1887-1915) was the grandson of Canon
Moseley, a distinguished mathematical physicist, and the
son of Professor H. N. Moseley, at one time Linacre Pro-
fessor of Zoology at Oxford. He took his degree at Oxford,
but received his scientific training mainly from Rutherford
at Manchester. After Laue, at Munich, had proved the
existence of a diffraction effect of crystals on X-rays, and
Professor William Henry Bragg had developed and improved
the methods of observation, Moseley set himself the task of
determining the fundamental vibrations of the atoms which
give rise to the X-rays. The research required exceptional
experimental skill, and great powers of devising new methods

1 For a detailed account of these investigations see Rutherford,
" Radio-activity."

Ernest Rutherford, Henry Moseley 185

of investigation, and the result proved of the highest value.
The wave-lengths to be measured are less than the thousandth
part of that of visible rays, and in that region the arrange-
ment of the lines was found to be the same for all elements ;
but proceeding from lower to higher atomic weights, the
spectrum was bodily displaced by a definite amount towards
the shorter wave-lengths. To see the full bearing of this
investigation, we must refer to the theory which Rutherford
had formed on the constitution of atoms, based mainly on
his experiments on the scattering of a particles by molecules
of matter. According to that theory, each atom possesses a
positively charged nucleus of exceedingly small dimensions.
The nucleus is made up of definite numbers of unit charges,
and if we arrange the elements in order of their atomic
weights, it is natural to suppose that the total charge
increases by one unit as we pass from one element to the next.
We may take the atomic number (meaning the number of
charges) as the characteristic of each element, and deal,
therefore, with figures which are successive integers, rather
than with the irregularly increasing numbers representing the
atomic weights. Moseley 's experiments prove that the high
frequency spectrum of the elements which he examined is
completely defined by the atomic number. It may be antici-
pated that this will prove to be the foundation of a new and
more precise chemistry, as other properties will be certain
to be intimately connected with the forces which regulate the
spectra. In confirmation of this, it may be stated that
Moseley in fixing the atomic number had to invert the order
in the case of potassium and argon, and that of cobalt and
nickel, and in both instances it is found that the chemical
properties agree with the spectroscopic evidence, and not
with that of the order of atomic weights.

Moseley's results, while showing that all elements can be
placed in a certain definite order almost identical with that
of the atomic weights, allow us also to discover the gaps
which we may confidently expect to see filled up by hitherto
undiscovered elements. Eighty-three are known at present
and Moseley's table of results shows nine gaps between
argon and the heaviest of the metals, uranium. The total
number of elements reached, when the gaps are filled, will be

186 Britain's Heritage of Science

ninety-three; but some authorities believe in the existence
of two further elements lighter than helium.

Moseley's magnificent researches came to a sudden and
tragic end. On the threshold of a career of singular promise,
looking towards a future pregnant with discoveries that
could not fail to fall to his genius and enthusiasm, he answered
the call to arms at the outbreak of the war; and a Turkish
bullet cut short a life precious to the peaceful glory of his
country, but gladly surrendered in its hour of need. That
also is a heritage which will go down to posterity.

187

CHAPTER VI

(Physical Science)

SOME INDUSTRIAL APPLICATIONS

IT is not intended here to catalogue, much less to discuss,
the multitude of practical applications of science which
have originated in this country during the last century. To
mention merely the manufacture of steel, the building of
bridges, and the evolution of the modern steam-engine is
sufficient to illustrate the all-pervading influence of science
on our industries.

The scientific production of steel originated with Ben-
jamin Huntsman (1704—1776), a clockmaker of Doncaster,
who discovered the process of making cast steel by melting
in crucibles. Starting works in Sheffield, he was the first to
introduce a material of uniform temper and composition
which could in the modern sense be termed steel. Much
might be said on the more recent developments of the steel
industry by Henry Bessemer (1813-1898), and on other in-
ventions, such as Sir Charles Parsons' steam-turbine, one of
the greatest triumphs that engineering skill has ever achieved.
But we must content ourselves with a few selected examples
illustrating the effects of pure scientific research on that
complex organization of the community which usually goes
by the name of civilization.

So much in our modern life depends on the facilities for
rapid mutual intercourse that it is curious to note how
new devices have often supplied the means before there
was a demand. The capacity of inventing outpaced the
power of the imagination to understand the use of the inven-
tion : the supply had to create the demand. Thus, when
Sir Francis Ronalds (1788-1873) submitted to the Govern-
ment in 1816 the design of an electric telegraph which he

188 Britain's Heritage of Science

had actually tried and found to work with a length of eight
miles of wire, the reply of the Secretary of the Admiralty
was that <v telegraphs of any kind are now totally unnecessary
and that no other than the one now in use will be adopted."
The word " now " seems to have referred to the conclusion of
the French war, and the telegraph mentioned as being in use
was the semaphore.

Ronalds was the son of a London merchant ; his method
of transmitting signals consisted in charging and discharging
an electroscope through a long wire. In his experiments he
used a length of eight miles of wire, properly insulated and
embedded in the soil of a garden in Hammersmith. The
distinguishing feature of his apparatus consisted in an arrange-
ment founded on the same principle as the one so successfully
employed in the type-printing arrangement invented at a
much later date by Hughes. Two discs bearing the letters
of the alphabet near their circumferences were made to
rotate with the same speed at the two ends of the line. The
electroscope placed at the receiving end was discharged from
the sending end. The sender watched the moment when
the required letter passed a certain position, and the same
letter passing the corresponding position at the receiving
end at the moment of discharge could therefore be read off.
The two discs were adjusted by means of a signal before the
message was sent, and it only remained to ensure that the
discs rotated synchronously during the time it took to send
the message. Bits of the original wire with its insulating
covering were dug out later, and are now preserved in the
Science Museum at South Kensington.

When the electromagnetic effects of currents had been
discovered, experiments by Gauss and Weber, Schilling and
Steinheil showed how they could be utilized in transmitting
signals. These experiments became known in England
through William Fothergill Cooke (1806-1879), knighted in
1869) who, in conjunction with Wheatstone, set to work to
devise a system of telegraphy that could be commercially
successful. The main difficulty was to reduce the number of
wires, which were at first thought to be necessary for indi-
cating the twenty -five letters; in this respect Ronalds had
been ahead of his successors. The difficulty was overcome

Telegraphy 189

by an alphabet of signs introduced by the American inventor
Morse, but an alternative one-wire system of Cooke and
Wheatstone in which the letters are directly indicated on a dial,
though much slower in its working, continued to be employed
in the British Telegraph Service at stations where it was
difficult to obtain operators sufficiently practised in the
Morse code. Subsequent improvements in telegraphy over
land lines are mainly of technical interest.

An entirely new set of problems arose when submarine
cables had to be laid across the oceans. As water is not an
insulator like air, the conductor which serves for the trans-
mission of the message has to be surrounded by a non-
conducting material like guttapercha. The copper wire inside
and the water outside separated by an insulating substance
then act like a condenser which must be charged up before a
steady electric current can flow through the wire. This
retards the transmission, and otherwise complicates the
effects, so that the ordinary telegraphic apparatus become
useless. Lord Kelvin's inventive genius soon supplied a
suitable instrument, but there were other dangers ahead, such
as the enormous mechanical stresses to which the cables are
exposed, and the destructive effects of submarine boring
animals. The credit of overcoming these difficulties is largely
due to Robert Newall, whose name has already been
referred to in connexion with Astronomy. As a practical
engineer, Newall had improved the manufacture of wire
rope to such an extent that quite a new industry may be
said to have originated through his efforts. He used the
experience gained by introducing wires to strengthen the
cables and inventing suitable appliances for paying them out.
The first commercially successful cable was laid across the
Straits of Dover in 1857, and the possibility of telegraphic
communication between Europe and America was then
opened out. In July, 1857, a cable was ready, and the shore
end was fixed at Valentia ; but the cable snapped when
380 miles had been laid. In the following year, after a further
failure, a cable was finally stretched across the Atlantic ; but,
unfortunately, Kelvin's instructions were ignored and high
potential currents were used to transmit the messages,
with the result .that the insulation was completely ruined.

190 Britain's Heritage of Science

The next attempt, made after an interval of eight years,
was again unsuccessful; but in 1866 the Or eat Eastern
laid its cable without mishap, and was even able to pick up
the lost end of the one that had broken in the previous year.
Since then submarine cables, mostly manufactured in Eng-
land, have rapidly increased, and their total length now at
work would, if joined end to end, be able to pass ten times
round the equator.

The success of cables depends so much on the durability
of the insulating material that this seems to be the place
for attention to the services of Thomas Hancock (1786-
1865), the founder of the india-rubber trade in England.
His work is well described in the " Dictionary of National
Biography," from which the following account is — with a
few omissions — transcribed. Observing that two freshly
cut surfaces of india-rubber readily adhered by simple
pressure, Hancock was led to the invention of the " masti-
cator," as it was afterwards called, by the aid of which
pieces of india-rubber were worked up into a plastic and
homogeneous mass. With the invention of this process,
which was perfected about 1821, the india-rubber trade
commenced. Eventually, Hancock became a partner in
the firm of Charles Macintosh and Company, though he still
carried on his business in London. In 1842 specimens of
" cured " india-rubber, prepared in America by Charles
Goodyear according to a secret process, were exhibited in
this country. Hancock investigated the matter, and dis-
covered that when india-rubber was exposed to the action
cf sulphur at a certain temperature a change took place;
he thus obtained " vulcanized " india-rubber. This was
patented in 1843. Although Hancock was not the inventor
of vulcanizing in the strictest sense of the word, he first
showed that sulphur alone is sufficient to effect the change,
whereas Goodyear employed other substances in addition.
Hancock also discovered that, if the vulcanizing process be
continued and a higher temperature employed, a horny
substance, now called vulcanite or ebonite, is produced.

David Edward Hughes (1831-1900), whose name has
already been mentioned above, was born in London, but
his parents emigrated to the United States when he was

William Thomson, Lord Kelvin

T. Hancock, D. E. Hughes, W. Sturgeon 191

seven years old. He was connected for a time with a college
in Kentucky, first as Professor of Music and then as a
teacher of Natural Philosophy, but gave up the academic
career, at the age of twenty-three, to supervise the manu-
facture of the type-printing machine which he had invented.
Everyone is now familiar with that perfect little instrument
which distributes typed messages simultaneously all over a
city. The income which the inventor derived from it gave
him the desired leisure for further scientific investigations.
His most important discovery is that of the microphone, in
which two pieces of carbon are in loose contact, making
an electric connexion that is exceedingly sensitive to the
slightest disturbance caused by a wave of sound or an
electric impulse. The carbon contact was soon introduced
into telephone transmitters, and helped much to make tele-
phones serviceable for ordinary use. In observing the effect
of electric impulses in carbon contacts Hughes anticipated
the invention of the " coherer," which made the trans-
mission of wireless electric messages to great distances
possible. It is, indeed, related that, so far back as 1879,
Hughes could detect by the microphone " electric impulses "
at a distance of 500 yards.1 The researches on the microphone
and on another useful instrument, the " induction balance,"
were carried out in England, where Hughes spent the later
part of his life.

All industrial applications of electricity are based on
Faraday's discoveries, and Sturgeon's invention of the electro-
magnet. After it had been shown experimentally by the
former that an electric current is produced when a wire is
moved in a magnetic field, it was pretty obvious that appliances
could be constructed for generating currents by mechanical
means. There is no indication that at first anyone was aiming
at currents of great intensity; machines were constructed
partly on account of their scientific interest and partly to
be used for purposes of telegraphy. Sturgeon was the first to
attack the inverse problem of using a current to do mecha-
nical work, and it has been described in our first chapter
how Joule started his work by trying to improve the

1 " Encyclopaedia Britannica."

192 Britain's Heritage of Science

efficiency of electromagnetic engines. Between 1850 and
1860 many attempts were made to increase the intensity of
electric currents obtained by electrodynamic induction, but
the turning point came when, in the spring of 1867, Henry
Wilde, of Manchester, showed some remarkable experiments
in the rooms of the Royal Society. In the previous year he
had already described the main principle on which he relied
to increase the intensity of currents that could be obtained
by electromagnetic induction. A machine constructed accord-
ing to a model made by Werner Siemens, in which an armature
rotated in a magnetic field produced by a permanent magnet,
generated an electric current which fed a second and larger
machine in which the permanent magnets were replaced by
electromagnets. These were excited by the first current
and a much stronger magnetic field was produced : a more
powerful current was consequently obtained. This was led
in a third machine round still larger masses of iron, which
were thus magnetized, and finally a current emerged showing
effects of surprising intensity. A piece of iron half-an-inch
thick melted and burned when the current was made to pass
through it, and a rod of platinum two feet long and a quarter
of an inch in diameter was also seen to melt. A steam engine
of 15 h.p. was required to drive the shafts of the machines.
Eye-witnesses testify to the great impression created by
these experiments, and there can be little doubt that the
public then first began to recognize the potentialities of the
electric current. Rapid advances were quickly made, and
the modern " dynamo-machine " was soon evolved ; Wilde
himself had already called his machines by that name.

As soon as commercial interests are involved in scientific
appliances, new problems of an economic nature arise. The
weight of metal to be put into the different parts of the
machinery has to be adjusted so as to obtain the best
results at the least cost, and other matters have to be con-
sidered. Apart from some contributions by Lord Kelvin, it
may be said that the economics of the dynamo-machine
depend almost entirely on the researches of John Hopkinson,
who, perhaps, more than any other British man of science,
combined the commercial faculty with the highest scientific
attainments.

H. Wilde, J. Hopkinson, J. A. Ewing 193

John Hopkinson (1849-1898) was born in Manchester,
and after studying two years at Owens College entered
Trinity College, Cambridge. He graduated in 1871 as senior
wrangler, and in the following year was engaged by Messrs.
Chance Brothers, glass manufacturers, at Birmingham, as
engineering manager. In this position he devoted himself
to the improvement of lighthouse illumination, and intro-
duced the system of group flashing lights which is now
extensively used. In 1878 he settled in London as consulting
engineer, and during the next few years conducted his
classical researches on the efficiency of dynamo-machines.
These were completed later, in conjunction with his brother
Edward, by laying down the general principles by which the
performance of any machine may be predicted from its
design. Another important contribution to electric lighting
was his invention of the three-wire system of electrical
distribution.

The efficient working of most of our electrical machinery
depends on the magnetic properties of iron, and mention
must, therefore, here be made of the valuable investigations
of Professor J. A. Ewing, who first clearly pointed out the
inevitable dissipation of energy which occurs when a piece of
iron is subject to rapidly alternating magnetic forces, as it is,
for instance, in a transformer. Owing to a property of iron
which he called hysteresis, and which is a kind of internal
viscosity brought into action by the rapidly changing orienta-
tion of magnetic molecules, some of the energy will always be
converted into heat, and is lost as useful work. In other
respects also, Ewing has added much to our knowledge of
magnetism.

Our electrical industry owes much to William Edward
Ayrton (1847-1908), who was the first to introduce sound
methods of instruction in applied electricity. He was
the most successful and, for a time, the only teacher of the
subject. He organized the laboratories at Finsbury College,
and at the Central College, Kensington. Men came from
all parts of the world to be trained by him, and he knew how
to infuse his students with the spirit of research. In the
early days of the industry, the measuring instruments,
though suitable for a physical laboratory, could not easily

N

194 Britain's Heritage of Science

be moved, or protected against the disturbing effects to
be expected in a large workshop. Ayrton recognized the
want, and in conjunction with Professor ^ohn Perry designed
a number of reliable and practical instruments that could be
used in a factory. Some of these inventions have proved of
permanent value.

The applications of chemistry to the necessities of the
nation are predominant in times of war, and hardly less
universal in times of peace. Two great industries stand out
on account of their importance, enhanced as it is by the
interest attached to, and the instructive contrast presented
by, their historical development. While the alkali manu-
facture which has been prosecuted so successfully in this
country is based to a great extent on chemical processes
originated or perfected by foreign chemists, Leblanc, Solvay,
and Castner, the coal-tar colour industry, founded on pioneer
work done in England, was unable to hold its own against
foreign competition. There is this possibly to be said in
explanation of the difference. The chemistry of the alkali
manufacture is extremely simple, and the difficulties which
had to be overcome, though serious enough, were mostly on
the engineering side ; the colour industry, on the contrary,
depends, not only hi its initial stages but throughout, on
persistent and organized scientific research, requiring the
encouragement and support of the manufacturers. The
institution which is associated with its birth — the Royal
College of Chemistry — was an exotic growth disconnected
from any university, and without permanent influence on
university teaching. Its director, Hofmann, was, at that
period, concerned with training scientific men rather than
manufacturing chemists, and no efforts were made to bridge
the gap between the laboratory and the factory.

The alkali industry presents a more pleasing history,
Joshua Ward, of Twickenham (1685-1761), first commer-
cially produced oil of vitriol in glass globes of forty to fifty
gallons capacity, and a very important advance was made
by Dr. John Roebuck, of Birmingham (1718-1794), who, in
1746, erected the first lead chambers. A name more directly
connected with the manufacture of alkali is that of Joseph
Christopher Gamble (1776-1884), who was trained up for

W. E. Ayrton, Christopher Gamble 195

the Church, and while passing through his studies at Glasgow,
attended a course of chemistry under Dr. Cleghorn. He
became sufficiently interested to carry on privately chemical
experiments in his leisure time. After taking up his duties
as Presbyterian minister at Enniskillen, he saw hand-loom
weavers in his parish working the flax grown by farmers in
the neighbourhood, and prepared solutions of chlorine to
assist them in bleaching their linen. Finding that he could
utilize the residue left over from the production of chlorine in
producing Glauber salts, he decided to resign his ministry
and establish chemical works in Dublin. Here he manu-
factured bleaching powder, using the process patented by
Charles Tennant (1768-1838), the owner of the St. Rollox
Chemical Works, now merged in the United Alkali Company.
He further set up a plant to manufacture the necessary
sulphuric acid. Salt or brine, another indispensable ingre-
dient, had, however, to be obtained from a distance, and this
led him ultimately to leave Ireland, and build works at
St. Helens. There he was associated during ten years with
James Muspratt, and afterwards with the brothers Cross-
field, soap-boilers, of Warrington. The trouble arising from
the damage done to the surrounding country by the noxious
gases set free in the process of manufacture hampered the
work considerably, and Gamble was slow to adopt the proper
remedies. The enmity of his neighbours and ill-health
ultimately made him abandon his work altogether.

To appreciate the work done by the chemical manu-
facturer in Gamble's time, it must be remembered that they
had generally to manufacture all the appliances they required.
Earthenware pots of sufficient size had to be produced, and
Gamble, blowpipe in hand, made his own thermometers and
hydrometers.

" Alkali " is an Arabic word originally applied to the ashes
of plants, and subsequently to the products derived from
these ashes, consisting of carbonate of soda and carbonate
of potash. The properties of these substances are so similar
that at first they were not distinguished as separate bodies.
As chemistry advanced, their metallic bases, sodium and
potassium, were grouped together under the term " alkali
metals," but technically, when the alkali industry is referred

N 2

196 Britain's Heritage of Science

to, it includes only the sodium compounds, and of these,
strictly speaking, only the hydrate and the carbonate ;
but the manufacture of sodium sulphate and of hydro-
chloric acid is inseparably connected with the same in-
dustry. The first successful process of obtaining carbonate
of sodium is due to Leblanc, a French chemist, and one of
the victims of the French Revolution. Leblanc was born in
1753, near Orleans. He was first trained in an apothecary's
shop, but proceeded to the study of medicine, and was
appointed surgeon to the Duke of Orleans. In 1775 the
French Academy of Sciences offered a prize for the best
practical process of producing soda from common salt.
There were several competitors, but none of them were
judged worthy of receiving the prize. Nevertheless, Leblanc
patented his process, and the Duke of Orleans supplied the
capital for establishing works on a manufacturing scale.
But his connexion with that nobleman proved to be his
undoing. The Duke was executed, and the works were con-
fiscated. Leblanc struggled on in dire poverty for thirteen
years, when his property was returned to him by the Emperor
Napoleon. But it was too late; he had no capital to start
afresh, took refuge in a workhouse, and died by his own
hand.

James Muspratt (1793-1886), who introduced the Leblanc
process into England, was born in Dublin, and as a boy was
apprenticed to a wholesale druggist; he quarrelled with his
master, and went to Spain to take part in the Peninsular
War. His great ambition was to obtain a commission in the
cavalry; in this he was unsuccessful, and, refusing to accept
the position in the infantry which was offered him, he
followed the army in the wake of the troops. He fell ill,
made his way to Lisbon, but could not find a steamer to
take him home. Ultimately he secured an appointment as
midshipman in the Navy, and though promoted to the rank
of second officer, could not adapt himself to the strict disci-
pline of the Navy. He deserted while the vessel lay in the
Mumbles roadstead, and returned to Dublin. With the
knowledge gained during his apprenticeship and a small
inheritance, Muspratt then began his career as a manu-
facturing chemist. He started by making hydrochloric acid

James Muspratt 197

and prussiate of potash. This did not satisfy his ambitions,
and when, in the year 1823, the prohibitive salt tax was
greatly reduced, he determined to work the Leblanc process,
and crossed over to Liverpool in search of a suitable locality
to erect his works. Not being provided with sufficient capital
he continued during a few years the manufacture of prussiate
of potash, until in 1828 he joined partnership with Christopher
Gamble and together they erected the St. Helens works.
Separating again two years later, Muspratt took a new site
at Newton-le- Willows. The same trouble arose which, as
has already been mentioned, discouraged Gamble. Newton
was in the heart of an agricultural district, and the farmers
very naturally resented having their crops spoiled by the
fumes of hydrochloric acid. Muspratt's business was so
seriously interfered with by continuous litigation that he
abandoned his works in 1850; and yet, ever since 1835, he
might have got over his difficulties had he given a trial to
the coke tower condenser of William Gossage (1799-1877),
which had been brought to his notice by the inventor. In
these condensing towers, the hydrochloric acid, instead of being
allowed to escape, is collected, and forms a by-product of
considerable commercial value. Gossage's process enabled
the alkali industry to develop with great rapidity, so that in
the twenty years between 1852 and 1872, the annual pro-
duction of alkali rose from 26,000 to 94,000 tons. Moreover,
the invention allowed the Alkali Acts to be passed and
strictly enforced, to the great advantage of the country in
which the works were situated.

In the Leblanc process, sulphate of soda (salt cake) is
formed by the direct action of sulphuric acid on salt; the
sulphate is converted into the carbonate by bringing it into
intimate contact with limestone and coal, and heating the
mixture. In another method, which has to a great extent
replaced that of Leblanc, the salt is acted on by ammonium
bicarbonate, with the result that sodium bicarbonate and
chloride of ammonium are formed. The ammonium bicar-
bonate, which forms the basis of the reaction, is generated
by saturating a salt solution with the ammonia obtained in
the recovery of the plant, and forcing carbonic acid gas into
the liquid. The process was first invented by G. Dyer and

198 Britain's Heritage of Science

J. Hemming in 1838, and worked on a small scale in White-
chapel. Muspratt also had given it a trial at Newton, but
abandoned it again. After protracted investigations, the
Belgian chemist, Ernest Solvay, overcame the main manu-
facturing difficulties, and took out a patent in 1872. In the
meantime, Ludwig Mond (1839-1909) had settled in England
at the age of 23, and had gained practical experience with the
Leblanc process while occupied in some chemical works at
Widnes. Recognizing the possibilities of the ammonia-soda
process, he obtained a licence from Solvay, and in partnership
with Sir John Brunner, founded in 1873 the great chemical
works near North wieh. Further difficulties were experienced,
but these were gradually overcome, mainly by improved
devices for recovering the ammonia, on which the commercial
success of the process largely depends.

A third method of making alkalies became possible when
the introduction of dynamo-machines provided an easy
means of obtaining strong electric currents. Various electro-
lytic processes were then devised and patented. In the
Castner-KeUner method, used extensively in this country,
the kathode of the electrolytic trough is formed by mer-
cury, and the sodium is transferred by the current from the
solution to the mercury with which it amalgamates; by a
self-acting arrangement the amalgam is removed before it
becomes strong enough to act on the water. That action is
ultimately allowed to take place in another vessel, where a
solution of caustic soda is formed.

Among the chemical engineers of the alkali trade, Henry
Deacon (1822-1876) and Walter Weldon (1832-1885) also
hold distinguished places. They both successfully invented
independent and quite different processes for the manu-
facture of chlorine, which are still in use, though partly super-
seded by electrolytic methods. An important improvement
in the manufacture of sulphuric acid was made by J. Glover,
who, in 1866, introduced the important de-nitrating tower.

In the early forties of last century a determined effort
to promote chemical research was made in London. With
the support of Faraday and Brande, it was at first intended
to attach the necessary laboratories to the Royal Institution,
but on closer consideration the available space was found to

L. Mond, W. Weldon, W. Perkin 199

be insufficient, and it was decided to establish a separate
institution, under the name of the Royal College of Chemistry.
The proposal matured largely through the influence of the
Prince Consort and the Queen's physician, Sir James Clark.
Temporary accommodation was found in George Street,
Hanover Square, until a larger building in Oxford Street
could be adapted. Justus Liebig, whose authority in questions
of chemistry was paramount at the time, was asked to
recommend a suitable director for the new institution, and
ultimately August Wilhelm Hofmann, a young assistant at
the University of Bonn, accepted the appointment. The
school was opened in 1845, and Hofmann threw himself
so heartily into the work that it soon attracted a large
number of promising pupils. It is, indeed, remarkable to
find among the early students of the Royal College so many
men who subsequently rose to eminence ; we note among them
Sir William Crookes, Sir Frederick Abel, Herbert Macleod, and
Sir William Perkin. The College continued until 1864, when
it was absorbed into the School of Mines. Perkin (1838-
1907) was fifteen years old when he came under the influence
of Hofmann. After passing through the ordinary training,
he was appointed honorary assistant to his teacher, and
henceforward devoted himself to research work. Hofmann's
own investigations at the time dealt with the organic
compounds derived from coal-tar; it was a purely scientific
research, undertaken without reference to any industrial
applications. Perkin was set to work on anthracite, and,
though interesting results were obtained, the chief value of
his early work was the acquisition of the experience which
he was to turn to such good account later.

The artificial production, or synthesis, as it is techni-
cally called, of natural organic compounds was then in its
infancy, and it was generally supposed that if, by abstracting
or adding oxygen or water, a compound could be formed
having the same number of oxygen, carbon, and hydrogen
atoms as the desired substance, the synthesis was likely
to be successful. Hofmann had suggested the artificial pro-
duction of quinine as a useful subject for research. The
problem attracted Perkin, and as he was at the time busy
with other work for his Professor, he decided to pursue the

200 Britain's Heritage of Science

investigation in the private laboratory he had established at
home. Following the deceptive guidance of the accepted
doctrine, he tried to synthesize quinine by treating one of the
coal-tar products with bichromate of potassium, but only
obtained a dirty reddish-brown precipitate. Maxwell once
said that he never stopped a man from carrying out an
unpromising research, because, though he would almost
certainly not find what he expected, he might find some-
thing else. Perkin had found something else, and showed
the proper researching instinct by accepting the hint.
Replacing the more complicated compound which he had
used by another coal-tar product, " aniline," he obtained
an almost black precipitate, which, on further examination,
proved to have dyeing properties. This led to the discovery
of aniline purple, later called " mauve," the first of the arti-
ficial colours. Perkin saw the possibility of a useful application
before him, and sent a sample of the dye to Messrs. Puller,
of Perth, who, recognizing its value, replied : "If your
discovery does not make the process too expensive, it is
decidedly one of the most valuable that has come out for a
long time."

Perkin resigned his position at the Royal College, and
with the assistance of his father built a factory at Greenford
Green, near Sudbury. To supply the dye cheaply, an econo-
mical method of preparing aniline had to be worked out.
This was first accomplished by the French chemist Bechamp,
whose share in the work was always fully recognized by
Perkin. The new dye-stuff was brought into the market
towards the end of 1857, and the demand for it increased
rapidly.

The aniline dyes are products which do not occur in nature.
A fresh departure was made in 1868, when Graebe and Lieber-
mann succeeded in the artificial formation of alizarin, the
dyeing principle of the madder plant. The method used was,
however, too costly to hold out any hope of competing
successfully with the product derived directly from the
plant, which was grown extensively in the south of France.
Within a year Perkin invented another process that promised
and attained commercial success. In the meantime, Graebe
and Liebermann had independently been led to the same

W. Perkin, E, C. Nicholson 201

method. The Greenford factory, however, was ready to
start work at once, and until 1873 there was practically no
competition with the coal-tar dyes produced in this country.
In his report on the exhibition of 1862, Hofmann
wrote : —

" England will, beyond question, at no distant date
become, herself, the greatest colour- producing country
in the world; nay, by the strangest of revolutions, she
may, ere long, send her coal-derived blues to indigo-
growing India; her tar-distilled crimson to cochineal-
producing Mexico, and her fossil substitutes of quercitron
and safflower to China, Japan and other countries, whence
these articles are now derived."

This is not the place to discuss the causes which have
falsified Hofmann's prophecy. The " near future " of his
prediction is passed, but another future lies ahead of us.

Perkin also carried on investigations of a great value in
pure science, even during the busy time of his industrial
enterprises. He sold his factory in 1874, devoting himself to
the time of his death to a life of scientific research.

Among the pupils working in the laboratories at George
Street we find Edward Chambers Nicholson (1827-1890),
of whom Hofmann, at a later period, wrote : " He united
the genius of the manufacturer with the habits of a scientific
investigator." In his first research he determined the con-
stitution of strychnine. After leaving the Royal College,
he became associated with Messrs. Maule and Simpson in
the preparation of various chemical products, turning his
attention ultimately to colouring matters. His name is
chiefly connected with the manufacture of " regina purple "
and " Nicholson's blue."

A worthy successor of Perkin and Nicholson might,
with proper opportunities, have been found in Raphael
Meldola (1849-1915), who, between 1879 and 1885, made
important discoveries of new dye-stuffs. But though he
was during eight years connected with a firm manufacturing
colours, he received little encouragement from his employers,
and his work bore no immediate fruit. Meldola always held
the opinion that the decline of the colour industry in
England was not due, as is commonly asserted, to the

202 Britain's Heritage of Science

defects of our patent laws, or other restrictions imposed by
the legislature of the country, but to the neglect of continued
scientific research within the factory.

Sir Frederick Abel (1827-1902) has been mentioned as
one of the students of the Royal College of Chemistry. His
subsequent work, carried on while he occupied the position
of Professor of Chemistry at the Koyal Military Academy
and Chemical Advisor to the War Department, dealt mainly
with the manufacture of explosives. Through his efforts
guncotton could be made and handled without danger, and
cordite is the joint invention of himself and Sir James Dewar.
He also designed the apparatus, legalized in 1879, for the
determination of the flash point of petroleum.

The name of Lyon Playfair (1819-1898) deserves to be
remembered as one who actively encouraged research through-
out his life, and exercised a considerable amount of influence
in promoting scientific enterprises. He was born in India,
educated at St. Andrews, and subsequently studied medicine
at Glasgow. Attracted towards chemistry by the teaching
of Thomas Graham, he went to study the subject under
Liebig at Giessen. For two years he managed the chemical
department of some print works in Clitheroe. Though he
subsequently held for a time the Professorship of Chemistry
at the Royal Institution in Manchester, at the School of
Mines in London and at the University of Edinburgh, it
is neither as a teacher nor investigator, but rather as a con-
sistent upholder of scientific principles, that he has left
his mark. He had a considerable share in the organization
of the Great Exhibition of 1851, and in the foundation of the
Department of Science and Art. In 1844 he sat on the Royal
Commission for the examination of the sanitary conditions
of large towns and public districts, and maintained through-
out his life a great interest in that subject. He served on
many other Royal Commissions. In 1868, Playfair was
returned as the first representative in Parliament of the
Universities of St. Andrews, and in 1885 was elected member
for the southern division of Leeds. He held office as Post-
master-General, and later as Vice-President of the Council
of Education. The honour of a peerage was conferred upon
him in 1892.

203

CHAPTER VII

SCIENTIFIC INSTITUTIONS

GREAT ideas spring from individual brains, but a com -
bination of brains working through scientific organi-
zations may perform important functions in stimulating
research, accumulating material or carrying out experiments
which are beyond the means of one man. An organization
is generally called into existence for a particular purpose,
but to be permanently successful its constitution must be
sufficiently elastic to allow a change of methods or even of
aims when the original need has ceased to be urgent or
fresh requirements have appeared. This elasticity has,
indeed, been a distinguishing feature of our own scientific
institutions, which have generally been able to adapt them-
selves to the changing circumstances of the time.

The origin of the Royal Society of London may be traced
to weekly meetings of men engaged in philosophical enquiries,
who came together to discuss questions of scientific interest.
These meetings began about 1645. A few years later
some of the members moved to Oxford, and independently
met in that University. The London meetings were inter-
rupted in 1658, owing to political troubles ; but, after the
return of Charles II., it was decided to establish a more
formal organization. A society was then formed which
met at Gresham College; the Bang became interested in
its work, with the result that it obtained a charter in 1662,
with the title of " The Royal Society." Further privileges
were given in a second charter,1 which was granted and
signed on May 13th, 1663, and the regular activity of the

1 The second charter confers the present title : " The Royal
Society of London," and adds its purpose : " for promoting Natural
Knowledge (pro scientia naturali promovenda)."

204 Britain's Heritage of Science

Society begins with that date. Twenty-one members were
named in the charter to constitute the first Council. Ninety-
four additional Fellows were selected by that body shortly
afterwards, of whom comparatively few are known by their
scientific work. Men of general culture sympathetic to the
revival of learning, statesmen, and even poets, were freely
included. It was not only science that benefited by this
liberal interpretation of the functions of the Society, for,
quoting Professor Oliver Elton,1 " The activities of the
newly founded Royal Society told directly upon literature,
and counted powerfully in the organization of a clear uniform
prose — the close, naked, natural way of speaking, which the
historian of the Society, Sprat, cites as part of its programme."
The meetings of the Royal Society, at first, served mainly to
promote friendly intercourse between its Fellows; experi-
ments were shown by a specially appointed " curator,"
subjects were proposed for investigation, and sometimes
Fellows were asked to undertake particular researches.
The publication of results did not originally form any
prominent part of the work, and only gradually gained
importance.

The preceding pages have been full of examples illus-
trating the discoveries made by Fellows of the Society;
we are here concerned with the influence which the Society
exerted in its corporate capacity. From the beginning it
acted as adviser to the Government in scientific matters,
and interested itself in the general welfare of the country.
During the first year of its existence, the King expressed the
wish that " no patent should be passed for any physical or
mechanical invention, until examined by the Society." In
the same year a report was presented and approved by the
Society " to plant potatoes, and to persuade their friends
to do the same, in order to alleviate the distress that would
accompany a scarcity of food." In 1732 it took measures
to promote the practice of inoculation. In 1750, its assistance
was invoked for the purpose of improving the distressing
state of ventilation of prisons, which was the cause of the
high death rate due to "jail fever." Sir John Pringle and

1 ** Encyclopaedia Britannica," Article on English Literature.

The Royal Society 205

Dr. Hales on behalf of the Society recommended the use
of ventilators, and these being introduced/ the number of
deaths in Newgate was reduced from seven or eight a week
to about two in a month.

In March 1769, the Dean and Chapter of St. Paul's
requested the Society's advice as to the most effectual
method of fixing electrical conductors on the cathedral to
protect it against the dangers of lightning. A committee was
appointed, including John Canton and Benjamin Franklin,
and reported on the subject; among the recommendations
adopted by the authorities was that of using the waterpipes
to serve as conductors between the roof and the ground.
Three years later a similar request was received from the
Government to protect powder magazines, and in 1820 the
Society advised the Admiralty on a system of lightning
conductors for use on ships which had been proposed by
Sir Snow Harris. In May 1824 the Council of the Society
appointed a Committee " for the improvement of glass for
optical purposes." Valuable results were obtained with glasses
prepared under the direction of Faraday, and examined by
John Dollond and Sir John Herschel. Unfortunately, owing
to the important electrical experiments which then engaged
the attention of Faraday, the Committee did not proceed
with the further proposal to organize the manufacture of
optical glass for general sale.

The indefatigable first curator of the Society had, a
few years after its foundation, formed the nucleus of a
collection of " natural rarities," and this gradually grew
into an important collection or " repository," enriched by
contributions from distant countries. Ultimately, the greater
part of it was handed to the British Museum, but the follow-
ing letter, addressed by three Fellows of the Society to the
Hudson Bay Company in 1777, shows that the specimens
presented were examined with a view to their general
utility : —

" Having endeavoured to find out whether some of
the natural productions which you have been so obliging
as to present to the Royal Society may not furnish
materials for our manufactures, we take the liberty of
stating to you the result of our enquiry. We have put some

206 Britain's Heritage of Science

parts of one of the buffalo's hides into the hands of a tanner,
and are informed, both by a very experienced leather-
dresser and bookbinder, that it seems to be as good a
material as the skin of the Russian buffalo for book-
binding. If these skins, therefore, can be procured in any
quantity, the importation may answer well to the Com-
pany, and no further preparations of the hides will be
necessary in Hudson's Bay, than to dry them properly
with the hair OH, and to take care that the sea water does
not injure them on the passage. It is supposed that each
skin brought in this way to England may be worth about
four shillings. We also beg leave to present to the Com-
pany, in the name of the Society, a pair of stockings made
here from the hair of one of the buffalo's hides, which
hung near the neck, as also a hat ; but it may be proper to
inform you, that the greatest part of the materials used
in the latter is rabbit's hair, as that of the buffalo cannot
be worked into a proper consistence for this purpose,
without a mixture of some other hah1. As you have pre-
sented to the Society likewise a specimen of a wild swan,
we have put the skin into the hands of an importer, and
we thall, perhaps, surprise you when we inform you, that
if it had been in a state to be properly dressed, it would
have been worth at least a guinea and a half; so scarce
is this commodity at present, and so great is the demand
for powder-puffs, the best sort of which can only be made
from swansdown. We have stated, however, that the
akin sent from Hudson's Bay was absolutely spoilt by
not being properly prepared, though we are informed that
nothing further is necessary than the following simple
process. All the feathers must be pulled off as soon as
the swan is killed, leaving only the down on; after this
the skin must be cut off along the back, and stripped off
the body, then take all the fat away, and turning the
skin inside out, let it dry. As swan-skins, therefore, are
so valuable an article of commerce at present, and there
is a probability of procuring many of them from Hudson's
Bay, it may be worth while for the Company to purchase
one of them, for the more fully instructing their servants
in what state they should be sent over."

The Royal Society 207

Many scientific expeditions were promoted and organized
by the Royal Society. Through its efforts the Govern-
ment was induced to send out well-equipped expeditions
to observe the transits of Venus in 1761 and 1769, promi-
nence being given in their representation not only to the
importance of the occurrence, but to the circumstance that
the first and so far only observation of this rare event was
made by the Lancashire curate Horrocks,

In 1773 representations were made to the Earl of Sand-
wich, first Lord of the Admiralty, strongly urging the desira-
bility of organizing an Arctic Expedition, partly on the ground
that this might result in the cfiscovery of a passage to the
East Indies by or near the North Pole. The wishes of the
Society were complied with ; two ships, the Racehorse and
the Carcass, were fitted out, and an astronomer accompanied
the expedition, with instructions drawn up by a Committee
of the Royal Society. The ships returned without having
achieved much ; but in two later expeditions, leaving Eng-
land early in 1818 and in 1819, most valuable scientific
results were obtained by Colonel (afterwards General)
Sabine.

In 1784 the Council of the Royal Society petitioned
George III. to place funds at the disposal of the Society to
commence a geodetical survey, with a view to establishing a
trigonometrical connexion between the observatories of Paris
and Greenwich. The King gave his consent, and Major
General Roy was appointed to carry out the undertaking.
This was the origin of the British Survey Office. Its work
was hampered, at the outset, by the unsatisfactory nature
of the standards of length. Already, in 1742, the Royal
Society and the French Academy had instituted comparisons
between the standards of measures and weights of the two
countries which led to some improvement, and in 1758
a committee of the House of Commons enquired into the
subject; but no legislative action was taken until 1824.
The question presented considerable difficulties, because
the two original standards, one dating back to King
Henry VII., kept at the Tower, and the other made during
the reign of Queen Elizabeth, kept at the Exchequer, were
of the rudest description, and did not agree with each other.

208 Britain's Heritage of Science

Francis Baily in 1836, referring to the latter, writes : "A
common kitchen poker, filed at the ends by the most bungling
workman, would make as good a standard. It has been
broken asunder and the two pieces have been dovetailed
together, but so badly that the joint is nearly as loose as that
of a pair of tongs." In 1816 the Royal Society had received
from the Secretary of State a request for assistance in
ascertaining the length of a pendulum vibrating seconds of
time at different stations of the Trigonometrical Survey.
This brought the question of standards into prominence,
and led to much valuable work being done ; but in the final
construction of the present standards the Royal Astrono-
mical Society took the lead, under the energetic superin-
tendence of Francis Baily.

Greenwich Observatory, established by Charles II., was,
from its foundation, closely connected with the Royal Society.
In 1710 Queen Anne appointed its President and such other
Fellows as he might nominate to be visitors of the Obser-
vatory. For some time the Society exercised a real control
over the work, receiving regular reports, making recommen-
dations, and collecting the results for publication. At
present the Royal Astronomical Society is associated with
the Royal Society in nominating the members of the Board
of Visitors. The important work carried out at Greenwich
has been frequently referred to in these pages; it is recog-
nized as the leading observatory of the world, and fixes the
time used in all civilized countries.

The study of Meteorology owes much to the Royal Society,
which in 1725 provided at its own expense a number of baro
meters and thermometers to be used by its correspondents
in different parts of the world. In 1773 the Council organized,
under the superintendence of Henry Cavendish, regular
meteorological observations in its own building, including the
measurement of temperature, pressure, moisture, and wind
velocity. These observations were conducted, and published
annually in the Philosophical Transactions, for nearly sixty
years. They were discontinued because the situation of the
building was not considered suitable, and regular observa-
tions had been established at the Royal Observatory. A
meteorological department of the Board of Trade was super-

Greenwich Observatory, Meteorology 209

seded in 1867 by a Meteorological Committee of the Royal
Society, which was entrusted with the whole of the meteoro-
logical work of the country. This was followed, in 1877, by
the Meteorological Council, consisting of the President and
four members nominated by the Royal Society, together with
the Hydrographer of the Navy. Since 1905 a special
Committee of H.M. Treasury, containing two representatives
of the Royal Society, is entrusted with the meteorological
organization of the country.

In 1842 regular magnetical as well as meteorological
observations were instituted at Kew Observatory, built
in 1769 by King George III. for the purpose of observing
the transit of Venus which occurred in that year. It came
for a time under the direction of the British Association,
but was handed over to the Royal Society in 1881 ; it
passed to the National Physical Laboratory in 1905, and is
now under the control of the Meteorological Committee.
The Royal Society continues, however, to administer a Trust
Fund of £10,000 conveyed to it by John Peter Gassiot, for
the purpose of providing for magnetical and meteorological
observations, which are being taken at Kew and Eskdale-
muir. The directors of Kew Observatory included many
distinguished men; among them Francis Ronalds, inventor
of the first electric system of telegraphy, who designed and
introduced the self-registering meteorological instruments,
and Balfour Stewart, whose work has been mentioned in
Chapter V.

It was chiefly through the influence of General Sabine
that the Royal Society was, during many years, the chief
promoter of the study of Terrestrial Magnetism. Observa-
tories all over the world were, directly and indirectly, organ-
ized by that powerful and energetic personality. The East
India Company gave valuable help, and when the Royal
Society in the year 1840 approached the Russian Government,
a speedy reply was received through the Foreign Office that,
in consequence of the representations made by the Society,
Russia had established ten magnetical observatories in her
Empire, and was willing to provide the funds for a further
one to be erected at Pekin.

The National Physical Laboratory was established in

0

210 Britain's Heritage of Science

1899, and placed under the control of the Royal Society.
Its primary object is to provide proper standards of measure-
ment for all branches of science, to test materials, to verify
the indications of instruments and to determine physical
constants. To serve these purposes, it has to be provided
with means for carrying out researches on a large scale, more
especially on problems connected with the industrial appli-
cations of science. The Laboratory is administered by an
Executive Committee, on which six of the more important
technical societies are represented. From small beginnings
the Laboratory has grown, under the directorship of Sir
Richard Glazebrook, with quite remarkable rapidity, and at
present its total annual income amounts to £50,000, of which
nearly two-thirds is received for work done for private firms
or Government departments.

With foreign academies the Royal Society has always
maintained most friendly relationships ; intercourse between
scientific men of different countries was, indeed, one of its
primary objects. In May 1661, before the incorporation of
the Society by Royal Charter, one of its members gave an
account of the proceedings at a meeting of French scientists
who formed the nucleus of the future French Academy of
Science, and in July of the same year a letter was addressed
to them requesting the interchange of scientific informa-
tion. In a communication sent to the Council of the
Royal Society by Christian Huygens during the same month,
after referring to his observations on Saturn, the author writes
that the members of the French body were " excited to
emulation of the Society of London, and proposed applying
themselves to philosophical experiments;" and adds that
this is " a good effect produced by your example." The
" Academie des Sciences " began to meet regularly in 1666,
but was constituted finally only in the year 1699. The
intimate relationship between the two scientific societies was
illustrated in a striking manner when Sir Humphry Davy
visited Paris while France and England were at war with
each other. He was received with the highest honours,
awarded a gold medal (p. 115), and elected a foreign member.
In the early days of the Society, Mr. Henry Howard
(afterwards Duke of Norfolk) interested himself in securing

The Royal Society 211

correspondents in different parts of Europe, with a view to
adding specimens of interest to its collection, and obtain-
ing information of value to the industries of the country.
" Methinks," he writes, " it were worth our knowledge
whether there are not now some persons in Italy that know
the old Roman way of plaistering, and the art of tempering
tools to cut porphyry, the hardest of marbles " ; and, again :
" I am lately informed that there is a mineral salt plentifully
to be found in the mines of Calabria, which has this particu-
larity, that, being cast into the fire, cracks not, nor breaks
in pieces. A specimen of that also would be acceptable."1

The first communication from the then recently estab-
lished Academy of Sciences at Petrograd was received at
the last meeting over which Sir Isaac Newton presided.
After quoting the desire of the Czar to follow the English
example in encouraging and cultivating science, the letter
concludes with the assurance that the Russian Academicians
" are the more inclined to make their addresses to, and
desire most to have the approbation of, the Royal Society,
as being the first of its kind, and that which gave rise to all
the rest."

The Royal Society has always encouraged the formation
of scientific bodies of similar aims in other parts of the United
Kingdom. In 1684 such a society was established at Dublin,
with full encouragement of the authorities of the Royal
Society, offered also to a similar effort made at Edinburgh
in 1705. In 1731 a separate society for the improvement of
medical knowledge was instituted in the latter city, but was
re-modelled so as to include other subjects in 1739. It was this
body which, under the name of " Royal Society of Edin-
burgh," received its charter in 1783. The great work carried
out by the scientific men of Scotland and Ireland, described
in the preceding pages, is a sufficient indication of the influence
exerted by the Royal Societies of Edinburgh and Dublin,
which — as also the Irish Academy of Sciences (founded in
1782) — have always co-operated with the London Society in
their common aims. The Royal Society of Arts was founded
in 1753, for the promotion of Arts, Manufactures, and

1 Weld's "History of the Royal Society,*' VoL I., p. 189.

O 2

212 Britain's Heritage of Science

Commerce, and the success with which it has worked to
attain its objects needs no comment.

When science became more specialized, the need for
separate societies dealing with the more technical portions
of each subject began to grow. These societies now take an
important share in the promotion of scientific researches.
The Linnaean Society was founded in 1788, the Geological
Society in 1807, the Royal Astronomical Society in 1820,
and the Chemical Society in 1841.

What strikes the foreign visitor most when he enquires
into the working of British scientific institutions is that the
Royal Society receives no subvention from the Government.
While in all foreign academies, the members receive an annual
sum from the State, in England they pay both an entrance
fee and regular subscriptions. The great French naturalist,
Cuvier, has some interesting remarks on the subject.1 The
Royal Society, the oldest of the scientific academies, is, he
says, " sans contredit 1'une des premieres par les decouvertes
de ses membres," and he attributes this to the fact that, as
it depends for its subsistence on the contributions of its own
members, the number of Fellows must necessarily be large.
The more numerous a body, he argues, the smaller is the
number of those who control its administration ; hence the
Council of the Royal Society, in whom the administration
is vested, is a small body with great powers, and can exert
a stronger influence on the progress of science than con-
tinental academies can do.

So far from the Royal Society having ever received sub-
ventions by the Government for general purposes, its Council
resolved unanimously in 1798 to pay into the Bank of England
a sum of £500 as a voluntary contribution towards the
defence of the country. Up to that time, the whole expendi-
ture of the Society was paid out of the entrance fees and
subscriptions of the Fellows, the only legacy which had
been received being a sum of £500 from Lord Stanhope,
paid over in 1786. During the last century the financial
resources of the Society have, however, been increased by a
number of valuable endowments.

de 1'Institut," 1826, p. 219.

Thomas Young

The Royal Institution 213

The Society is now entrusted with the administration
of certain funds devoted by the Government to definite
purposes, such as grants towards scientific researches, and
the publication of scientific literature. It has been given
free use of its apartments, first in Gresham College, later in
Somerset House, and now in Burlington House.

There is no building in the world associated with so
many classical and revolutionizing researches as that in
which the Royal Institution is housed. The idea which led
to its foundation is generally ascribed to Count Rumf ord ;
the earliest document referring to the matter is an account
of a meeting held at the house of Sir Joseph Banks, the
President of the Royal Society, at which Count Rumf ord and
other Fellows of the Royal Society were present. The title
and purposes of the institution were then defined to be " for
diffusing the knowledge, and facilitating the general intro-
duction, of useful mechanical inventions and improvements ;
and for teaching, by courses of philosophical lectures and
experiments, the applications of science to the common
purposes of life."

The idea of research grew up in the time of Young and
Davy, though Count Rumford must have had it in mind
when through his influence the latter was appointed as first
Professor of Chemistry. Much has already been said about
the work of these two great philosophers, as well as that of
Faraday, who succeeded Davy. Their successors worthily
upheld the traditions of the Chairs. John Tyndall (1820-
1893) was appointed Professor of Natural Philosophy in
1854, and succeeded Faraday as superintendent of the labora-
tories in 1866. He spent a useful life in scientific research,
but will be remembered mainly as an advocate of scientific
principles and popularizer of science. His books have
inspired many young men to the pursuit of science, and the
one on " Heat as a Mode of Motion " still deserves to be
read as a clear exposition of the fundamental principles of
heat.

Sir James Dewar, who now occupies the Chair held by
Davy and Faraday, has made his name famous through his
researches on the liquefaction of gases. He was the first to
liquefy air on a large scale, and subsequently following up

214 Britain's Heritage of Science

some earlier work of Worblewsky, he succeeded in not only
liquefying, but also solidifying, hydrogen. By using liquid
hydrogen, he was finally able to condense helium. He made
extensive investigations on the properties of bodies at low
temperatures, and his determination of the specific heats of
elements as they approach the absolute zero of temperature
has thrown quite a new light on the laws which up till then
were believed to connect specific heat and atomic weight.
Referring to his discovery of the absorptive properties of
charcoal, we may quote the words of the President of the
Royal Society in awarding him the Copley Medal in 1916 :
" Many of the most interesting and important investigations
made in Physics in recent years would have been impossible
but for his invention of the method of obtaining very high
vacua by the use of charcoal immersed in liquid air or
hydrogen."

A few words may be said in conclusion on the activities
of the British Association, which held its first meeting
at York in 1831. Its object was mainly the same as that
which in the seventeenth century originated the meetings
which ultimately led to the foundation of the Royal Society.
British science in the nineteenth century could no longer be
confined to the metropolis, and the provision of a more
intimate and personal scientific intercourse between men
residing in different parts of the country became desirable.
To the outside world the meetings of the British Association
appear to be confined to annual discussions on a variety of
subjects; but the main work of the Association is carried
on throughout the year, and it can claim to have originated
scientific enterprises of the highest value and importance.
The introduction of scientific electrical units is the result of
work initiated by the British Association, and in great part
carried out by one of its Committees. Under the protection
and with the financial support of the same body, John Mime
was enabled to establish his international organization for the
observation of earth tremors, and the need for the establish-
ment of a National Physical Laboratory was first advocated
by Sir Oliver Lodge at one of the meetings of the British
Association.

The history of the British Association forms a good

The British Association 215

example of the advantages of a liberal and flexible constitu-
tion, which allows it to adjust its procedure and conditions
to the ever-changing and increasing requirements of science.

In concluding that part of Britain's heritage which deals
with Physical Science, we may express the hope that the
country will deserve, with increasing justification, the praise
bestowed upon it by Biot1 : " Souhaiter une chose utile aux
sciences c'etait avoir d'avance Tassentiment des savants
d'Angleterre et 1'approbation du gouvernement de ce pays
eclaire."

1 Cl M&noires de PInstitut de France," 1818.

216 Britain's Heritage of Science

CHAPTER VIII
BIOLOGICAL SCIENCE IN THE MIDDLE AGES

npHROUGHOUT the Middle Ages natural science was a
-I- study of the written word of ancient writers, whose
authority went unquestioned. Processes of observation or
experiment were barely known. To this mediaeval tradition
the age of the Tudors, in its attitude to scientific study, was
to a large extent loyal. Authority was still final and definite.
What Galen and Hippocrates, Aristotle and Pliny had written
was subject-matter for dispute, for discussion, for argument,
but not for direct investigation. In the same way the new
light derived from the Arabs, which spread through the
learned world at the latter end of the twelfth and at the
beginning of the thirteenth centuries, was treated as a
matter for dialectics by those who set the written word
before actual observation or experiment in Nature.

Let us consider the books in English at the disposal of
an average man in the latter half of the sixteenth century.
Through mediaeval times had drifted a certain " corpus "
of moralized natural history known as the " Physiologus,"
which was in essence a Bestiarium. It took various forms,
and was read throughout Europe and the Near East. This
" Physiologus " was primarily religious in its aim, but dealt
not only with the animals mentioned in the Bible but with
other and often mythical monsters. Scientifically the
zoology of the " Physiologus " was of the poorest; in fact,
the study of zoology was at its worst during the Middle
Ages; it had fallen far lower than in classical days. The
" Physiologus " had its origin in Alexandria in early Christian
times, and was translated into many tongues, including
Coptic. It was sometimes fathered upon Ambrose, but is
older than his day.

During the eleventh century a certain " Episcopus

Bartholomaeus Anglicus 217

incertus," one Theobaldus, made a metrical version of the
descriptions of twelve of the animals dealt with in this little
volume. This was published under the name " Physiologus
Theobaldi Episcopi de naturis duodecim animalium," the
earliest printed edition being that issued at Delft in 1487.
Numerous editions were published in many countries for the
following century or two, but the contents of the volume
were in a state of flux, additions and omissions appearing
in many of the issues.

But the chief book on natural history in the Middle Ages
was an encyclopaedia entitled " Liber de Proprietatibus
Rerum," compiled by the English Franciscan, Bartholomew
often called Bartholomaeus Anglicus, who probably wrote
some time about 1250, certainly before 1267, and in all
probability before 1260. Both before and after the invention
of printing this work had a wide circulation. The " Liber "
was translated into French by the order of Charles V., into
Spanish in 1372, then into Dutch, and in 1397 into English.
It was also the first book printed on paper which had been
made in England. This book is believed to have been the
source of much of Shakespeare's knowledge of natural history.
In 1582 the Rev. Stephen Bateman, D.D., domestic chaplain
to Bishop Parker, re-issued the English translation made by
John of Trevisa which had been printed in 1494 by Wynkyn
de Worde at Westminster. The book was entitled :

" Bateman uppon Bartholome. His Booke De Pro-
prietatibus Rerum : newly corrected, enlarged, and
amended, with such Additions as are requisite, unto
every severall Booke. Taken foorth of the most approved
Authors, the like heretofore not translated in English.
Profitable for all Estates, as well for the benefite of the
Mind of the Bodie." Lond. 1582, fol. Dedicated to
Lord Hunsdon.

Incomplete translations of Pliny from the French had
appeared in 1565, and again in 1587. In 1601 Philemon
Holland, M.D. (1552-1637), in later life headmaster of
Coventry Grammar School — " the translator generall in his
age," as Fuller calls him — published a more complete version
of Pliny under the title " The History of the World, commonly
called the Natural Historic of Caius Plinius Secundus."

218 Britain's Heritage of Science

This treats of all phases of nature, and contains a record
of all natural knowledge up to the time of the younger Pliny.
Nor must it be forgotten that the writings of Pliny and the
" Georgics " of Virgil were in constant use in the schools.

In the middle of the thirteenth century Roger Bacon
had pointed out that " There are two ways of knowing,
viz., by means of argument and by experiment," but for
three centuries onward it was " argument " which held the
field. Not that the sixteenth century failed to produce
enlightened men who were to preach a new doctrine. In
his educational work " De Tradendis Disciplinis " (1523)
Vives1 advocates " nature study " and even uses the expres-
sion. He tells us " That although the writings of the old
Greeks and Romans are the opinions of learned men, yet
not even all these opinions and judgments are to be accepted."
Vives recommends that the pupil should first be shown what
he can most readily perceive by the senses :

" So will he observe the nature of things in the
heavens, in clouds and in sunshine, in the plains, on the
mountains, in the woods. Hence he will seek out and
get to know many things from those who inhabit those
spots. Let him have recourse, for instance, to gardeners,
husbandmen, shepherds, and hunters, for this is what
Pliny and other great authors undoubtedly did ; for any
one man cannot possibly make all observations without
help in such a multitude and variety of directions. But
whether he observes anything himself, or hears any-
one relating his experience, not only let him keep eyes
and ears intent, but his whole mind also, for great and
exact concentration is necessary in observing every part
of nature."

We can but judge the state of zoology in Queen Elizabeth's
time by the books and writings that have come down to us,
and if we inquire what books and writings were available,
they will be found to fall under the three headings, Medicine,
Meldcraft, and Heraldry. From these subjects the paths
of progress in that science were advancing and converging.

1 A Spanish educationalist who came to England in 1523 and was
attached to Henry VIII. 's Court. Later he lectured at Oxford and
became a Fellow of Corpus Christi College there

Roger Bacon, Vesalius 219

The year that saw the birth of Shakespeare witnessed
in the remote island of Zante the death of Vesalius, who,
as a medical student at a hospital in Venice, had rubbed
shoulders with a young soldier, Ignatius Loyola, who six
years later founded the Order of the Jesuits. Vesalius,
who was born at Brussels on the last day of the year 1514,
was the first biologist to abandon authority. Dispensing
with the aid of unskilled barbers, he dissected the human
body with his own hands. Like Harvey, whose discovery
of the circulation of the blood dates but three years after
Skakespeare's death, he

" Sought for Truth in Truth's own Book,
The creatures, which by God Himself was writ,

And wisely thought 'twas fit,
Not to read Comments only upon it,
But on the original itself to look."

At the beginning of his scientific career, like his master
Sylvius, Professor at the College of France, Vesalius trusted
the written word of Galen more than he trusted his own
eyesight, but in the end his sight and his reason conquered,
and at last he taught only what he himself could see and
make his students see.

Vesalius was the founder of modern anatomy, physiology,
and, I think we may say, also of modern zoology and
botany, for the methods of these sciences are one. His
great work on " The Structure of the Human Body "
appeared at Basle in 1543, and was beginning to have
influence in England, but only amongst the learned, well
before the middle of the sixteenth century.

His English pupils, amongst whom was John Caius,
the third founder of Gonville and Caius College, helped to
spread his methods and principles in this country. Amongst
the many pupils of John Caius we may mention Thomas
Moffett. Comparatively few men in those days lived much
over fifty years, and Moffett, born in 1553, died in 1604.
He joined Trinity College in 1569, but migrated to Caius
in 1572, where he was nearly poisoned by eating mussels.
After taking his M.A. degree, he, as was the habit of the time,
studied abroad and received in 1578 the degree of M.D.
at Basle where he was a pupil of Felix Plater and of Zwinger.

220 Britain's Heritage of Science

The following year he travelled in Spain and Italy, and in
these countries he made an elaborate study of the silk-
worm, which doubtless led him to the study of insects in
general. He not only wrote a poem on the silk-worm,
but collected notes on the natural history of the Insecta.
These were published thirty years after his death under the
title " Insectorum sive Minimorum Animalium Theatrum —
ad vivum expressis Iconibus super quingentis illustratum."
An English translation entitled the " Theater of Insects "
was published as an appendix to Topsell's " History of
Four-Footed Beasts and Serpents-" in 1658.

Moffett was a many-sided man of science, a practising
physician, a traveller who at Copenhagen had known Tycho
Brahe, a courtier who took part in both diplomatic and
military service abroad, a poet and writer of epitaphs and
epigrams, a keen critic of diet, and for some time a member
of the House of Commons.

A friend of Moffett's was Thomas Penny, who entered
Trinity College, Cambridge, in 1550, and later became not
only a Prebendary of St. Paul's, but a sound botanist and
entomologist. Like so many men of the time, Penny
travelled extensively on the Continent. He visited Majorca,
lived in the south of France, and worked in Switzerland
with Gesner. He is believed to have been with Gesner
when he died, and he certainly helped to arrange the natu-
ral history specimens which the great master left. It was
probably through Penny that Gesner's drawings of butter-
flies passed into the care of Moffett, whose " Theatrum "
states on its title-page that it was begun by Edward
Wotton, Conrad Gesner, and Thomas Penny.

The contents of books revealing new knowledge diffused
themselves among the ordinary public in Queen Elizabeth's
time far more slowly than at present. On the other hand,
studies were then far less specialized than they now are.
For example, we find Milton placing medicine in the curri-
culum of a liberal education, and John Evelyn studying
" Physics " at Padua. Lord Herbert of Cherbury insists
on the necessity of a gentleman being able to diagnose and
treat disorders, and thinks he should have a knowledge of
anatomy, " Whosoever considers anatomy, I believe, will

Thomas Moffett, Thomas Penny 221

never be an atheist," was one of his recorded sayings.
Dealing with the matter broadly, I think we may endorse the
statement of Mr. Foster Watson : "It is noteworthy, that
in both botany and zoology the main advances were made
by professed physicians," and we must not forget that Eliza-
bethan botany was more advanced than Elizabethan zoology.

Something, however, was learned from husbandry and
field sport. " Let the student," says Vives in the above-
quoted passage, " have recourse, for instance, to gardeners,
husbandmen, shepherds, and hunters," and in " De rebus
rusticis " he says : " Let the boy read Cato, Varro, Columella,
Palladius." " Vitruvius is important for naming with the
greatest purity and accuracy most objects of the country."
Virgil with his marvellous account of apiculture and other
agricultural pursuits was much read during this period.

The gentlefolk also in Queen Elizabeth's time were much
interested in the study of heraldry, for, indeed, it was a
very gentlemanly pursuit. Gerard Legh's " Accedens of
Armory " (1562) and John Guillim's " Display of Heraldry "
(1610) included descriptions of creatures which enabled the
owners of animal crests and supporters to appreciate the
nature of what they bore and of what supported them.

In Elizabethan times, although a knowledge of physio-
logy and human anatomy was beginning to emerge; such
objects as comparative anatomy, morphology, and embryo-
logy were non-existent. In dealing with the animal king-
dom, the first need of the earlier writers on zoology was to
make some sort of classification, and even in the later Tudor
times such attempts at classification rested almost wholly on
external characteristics. These arid catalogues of animals
were usually lightened by the addition of notes on their
habits — often of the quaintest and most bizarre description
— and by short accounts of such medical properties as the
fantastic pharmacy of the sixteenth century attributed to
various beasts.

With one or two exceptions — astronomy on the physical
side, human anatomy on the biological — the reawakening
in science lagged a century or more behind the renascence
in literature and in art. What the leaders of thought and
of practice in the arts of writing, of painting and of sculpture

222 Britain's Heritage of Science

in western Europe were effecting in the latter part of the
fifteenth and throughout the sixteenth century began to
be paralleled in the investigations of the physical laws of
Nature only at the end of the sixteenth century and through-
out the first three quarters of the seventeenth.

Writing broadly, we may say that, during the Stewart
time, the sciences, as we now class them, were slowly but
surely separating themselves out from the general mass of
learning, segregating into secondary units; and from a
general amalgam of scientific knowledge, mathematics,
astronomy, physics, chemistry, geology, mineralogy, zoology,
botany, agriculture, even physiology (the offspring of anatomy
and chemistry) were beginning to assert claims to individual
and distinct existence. It was in the Stewart reigns that,
in England at any rate, the specialist began to emerge from
those who hitherto had " taken all knowledge to be " their
" province." Certain of the sciences, such as anatomy,
physiology and, to a great extent, zoology and botany, had
their inception in the art of medicine ; but the last two owed
much to the huntsman and the agriculturist.

The great outburst of scientific enquiry which occurred
during the seventeenth century was partly the result, and
partly the cause, of the invention of numerous new methods
and innumerable new instruments, by the use of which
advance in natural knowledge was immensely facilitated.

The barometer, the thermometer and the air pump, and,
later, the compound microscope, all came into being at the
earlier part of the seventeenth century, and by the middle
of the century were in the hands of whoever cared to use
them. Pepys, in 1664, acquired :

" a microscope and a scotoscope. For the first I
did give him £5 10s., a great price, but a most curious
bauble it is, and he says, as good, nay, the best he knows
in England. The other he gives me, and is of value;
and a curious curiosity it is to discover objects in a dark
room with."

Two years later, on August 19th, 1666, " comes by
agreement Mr. Reeves, bringing me a lantern " — it must
have been a magic lantern — " with pictures in glass, to make
strange things appear on a wall, very pretty."

Francis Bacon 223

As we pass from Elizabethan to Stewart times, we pass,
in most branches of literature, from men of genius to men
of talent, clever men, but not, to use a Germanism, epoch-
making men. In science, however, where England led the
world, the descent became an ascent. We leave Dr. Dee
and Edward Kelly, and we arrive at Harvey and Newton.

The gap between the mediaeval science which still
obtained in Queen Elizabeth's time and the science of the
Stewarts was bridged by Francis Bacon, in a way, but only
in a way. He was a reformer of the scientific method. He
was no innovator in the inductive method; others had
preceded him, but he, from his great position, clearly pointed
out that the writers and leaders of his time observed and
recorded facts in favour of ideas other than those hitherto
sanctioned by authority.

Bacon left a heritage to English science. His writings
and his thoughts are not always clear, but he firmly held,
and, with the authority which his personal eminence gave
him, firmly proclaimed, that the careful and systematic
investigation of natural phenomena and their accurate record
would give to man a power in this world which, in his time,
was hardly to be conceived. What he believed, what he
preached, he did not practise. " I only sound the clarion,
but I enter not into the battle " ; and yet this is not wholly
true, for, on a wintry March day, in 1626, in the neighbour-
hood of Barnet, he caught the chill which ended his life while
stuffing a fowl with snow, to see if cold would delay putre-
faction. Harvey, who was working whilst Bacon was writing,
said of him : " He writes philosophy like a Lord Chancellor."
This, perhaps, is true, but his writings show him a man,
weak and pitiful in some respects, yet with an abiding hope,
a sustained object in life, one who sought through evil days
and in adverse conditions " for the glory of God and the
relief of man's estate."

Though Bacon did not make any one single advance in
natural knowledge — though his precepts, as Whewell reminds
us, " are now practically useless " — yet he used his great
talents, his high position, to enforce upon the world a new
method of wrenching from Nature her secrets and, with
tireless patience and untiring passion, impressed upon his

224 Britain's Heritage of Science

contemporaries the conviction that there was t; a new
unexplored Kingdom of Knowledge within the reach and
grasp of man, if he will be humble enough, and patient
enough, and truthful enough to occupy it."

To turn to other evidence, the better diaries of any age
afford us, when faithfully written, as fair a clue as do the
dramatists of the average intelligent man's attitude towards
the general outlook of humanity on the problems of his ag;,
as they presented themselves to society at large. The
seventeenth century was unusually rich in volumes of auto-
biography and in diaries which the reading world will not
readily let die. The autobiography of the complaisant Lord
Herbert of Cherbury gives an interesting account of the
education of a highly-born youth at the end of the sixteenth
and the beginning of the seventeenth century. Lord Herbert
seems to have had a fair knowledge of Latin and Greek and
of logic when, in his thirteenth year, he went up to University
College, Oxford. Later, he " did attain the knowledge of
the French, Italian and Spanish languages," and, also,
learnt to sing his part at first sight in music and to play on
the lute. He approved of "so much logic as to enable men
to distinguish between truth and falsehood and help them to
discover fallacies, sophisms and that which the Schoolmen
call vicious arguments " ; and this, he considered, should
be followed by " some good sum of philosophy." He held
it also requisite to study geography, and this in no narrow
sense, laying stress upon the methods of government,
religions and manners of the several states as well as on their
relationships inter se and their policies. Though he advocated
an acquaintance with " the use of the celestial globes," he
did " not conceive yet the knowledge of judicial astronomy
so necessary, but only for general predictions; particular
events being neither intended by nor collected out of the
stars." Arithmetic and geometry he thought fit to learn,
as being most useful for keeping accounts and enabling a
gentleman to understand fortifications.

Perhaps the most characteristic feature of Lord Herbert's
acquirements was his knowledge of medicine and subjects
allied thereto. He conceived it a " fine study, and worthy
a gentleman to be a good botanic, that so he may know

Lord Herbert, John Evelyn 225

the nature of all herbs and plants." Further, " it will become
a gentleman to have some knowledge in medicine especially
the diagnostic part " ; and he urged that a gentleman should
know how to make medicines himself. He gives us a list
of the " pharmacopeias and anechodalies " which he has
in his own library, and certainly he had a knowledge of
anatomy and of the healing art — he refers to a wound which
penetrated to his father's " pia mater," a membrane for a
mention of which we should- *&s& in vain among the records
of modern ambassadors and gentlemen of the court. His
knowledge, however, was entirely empirical and founded
on the writings of Paracelsus and his followers; never-
theless, he prides himself on the cures he effected, and,
if one can trust the veracity of so self-satisfied an amateur
physician, they certainly fall but little short of the
miraculous.

John Evelyn, another example of a well-to-do and widely
cultivated man of the world, fond of dancing and skilled
in more than one musical instrument, was acquainted with
several foreign languages, including Spanish and German, and
was interested also in hieroglyphics. He studied medicine
in 1645 at Padua, and there acquired those " rare tables of
veins and nerves " which he afterwards gave to the Royal
Society; while at Paris, in 1647, he attended Lefevre's course
of chemistry, learned dancing and, above all, devoted himself
to horticulture.

But Evelyn's chief contribution to science, as already
indicated, was horticultural. He was devoted to his garden,
and, both at his native Wotton, and, later, at Sayes Court,
Deptford, spent much time in planting and planning land-
scape gardens, then much the fashion.

In the middle of the sixteenth century, the fact that
" nitre " promoted the growth of plants was beginning to
be recognized. Sir Kenelm Digby and the young Oxonian
John Mayow experimented de Sal-Nitro ; and, in 1675,
Evelyn writes : "I firmly believe that where saltpetre can
be obtained in plenty we should not need to find other
composts to ameliorate our ground." His well-known
" Sylva," published in 1664, had an immediate and a wide-
spread effect, and was, for many years, the standard book

P

226 Britain's Heritage of Science

on the subject of the culture of trees. It is held to be
responsible for a great outbreak of tree-planting. The
introduction to Nisbet's edition gives figures which demon-
strate the shortage in the available supply of oak timber
during the seventeenth century. The charm of Evelyn's
style and the practical nature of his book, which ran into
four editions before the author's death, arrested this decline
("be aye sticking in a tree; it will be growing, Jock, when
y're sleeping " as the laird of jfrtf^objadykes counselled his
son), and to the " Sylva " of John Evelyn is largely due the
fact that the oak timber used for the British ships which
fought the French in the eighteenth century sufficed, but
barely sufficed, for the national needs.

Pepys, whose naive and frank self-revelations have made
him the most popular and the most frequently read of diar-
ists, was not quite of the same class of student to which
Lord Herbert of Cherbury or John Evelyn belonged. But,
gifted as he was with an undying and insatiable curiosity,
nothing was too trivial or too odd for his notice and his
record; and, being an exceptionally able and hard-working
Government servant, he took great interest in anything
which was likely to affect the Navy. He discoursed with the
ingenious Dr. Kuffler " about his design to blow up ships,"
noticed " the strange nature of the sea- water in a dark night,
that it seemed like fire upon every stroke of the oar " —
an effect due, of course, to phosphorescent organisms float-
ing near the surface — and interested himself incessantly in
marine matters.

Physiology and mortuary objects had, for him, an interest
which was almost morbid. He is told that " negroes drounded
look white, and lose their blackness, which I never heard
before," describes how " one of a great family was . . .
hanged with a silken halter . . . of his own preparing,
not for the honour only " but because it strangles more
quickly. He attended regularly the early meetings of the
Royal Society at Gresham College, and showed the liveliest
interest in various investigations on the transfusion of
blood, respiration under reduced air pressure and many
other ingenious experiments and observations by Sir George
Ent and others. On January 20th, 1665, he took home

Samuel Pepys 227

" Micrographia," Hooke's book on microscopy — " a most
excellent piece, of which I am very proud."

Although Pepys had no scientific training — he only began
to learn the multiplication table when he was in his thirtieth
year, but, later, took the keenest pleasure in teaching it
to Mrs. Pepys — one could have wished that Mrs. Pepys1
views had been recorded — he, nevertheless, attained to the
Presidentship of the Royal Society. He had always delighted
in the company of " the virtuosos " and, in 1662, three years
after he began to study arithmetic he was admitted a Fellow
of their — the Royal — Society. In 1681 he was elected
President. This post he owed, not to any genius for science,
or to any great invention or generalization, but to his very
exceptional powers as an organizer and as a man of business,
to his integrity and to the abiding interest he ever showed
in the cause of the advancement of knowledge.

It has been said that a competent man of science should
be able to put into language " understanded of the people "
any problem, no matter how complex, at which he is working.
This seems hardly possible in the twentieth century. To
explain to a trained histologist double B functions or to a
skilled mathematician the intricacies of karyokinesis would
take a very long time. The introduction in all the sciences
of technical words is due not to any spirit of perverseness
on the part of modern savants ; these terms, long as they
usually are, serve as the shorthand of science. In the Stewart
times, however, an investigator could explain in simple
language to his friends what he was doing, and the advance
of natural science was keenly followed by all sorts and
conditions of men.

Whatever were the political and moral deficiencies of
the Stewart kings, no one of them lacked intelligence in
things artistic and scientific. At Whitehall, Charles II.
had his " little elaboratory, under his closet, a pretty place,"1
and was working there but a day or two before his death,
his illness disinclining him for his wonted exercise. The
king took a curious interest in anatomy; on May llth,
1663, Pierce, the surgeon, tells Pepys " that the other day

1 Pepys, January 16th, 1669.

P 2

228 Britain's Heritage of Science

Dr. Clerke and he did dissect two bodies, a man and a woman,
before the King, with which the King was highly pleased."
Pepys also records, February 17th, 1662-3, on the authority
of Edward Pickering, another story of a dissection in the
Royal closet by the king's own hands.

229

CHAPTER IX
BOTANY

IT is generally conceded that the first eminent English
- botanist was William Turner (born probably between
1510 and 1515, died 1568), educated at Pembroke College,
Cambridge. After the manner of his time, Turner was not
only a botanist but a zoologist ; to his work in this subject
we shall return later; he was further a most polemical
divine, and suffered much with the alternate ebb and flow
of the varying religious faiths which prevailed in the country
during the Tudor times. Turner's earliest work on botany
was the " Libellus de re Herbaria novus," 1538, which may
also be regarded as the first English book on Botany. In
this he gives, for the first time, the locality of many of our
native British plants. Ten years later he published a work
on " Names of Herbes in Greke, Latin, Englishe, Duche,
and Frenche, with the commune names that Herbaries and
Apothecaries use." His best known work, however, was
his " Herball," which was published in three parts, the
first part appearing in 1551, the second when he was exiled
abroad in 1562, and the third in 1568. This was by no
means the first " Herball " which had appeared in English,
but it had a certain originality about it and a certain
independence of view. Turner was especially opposed to
what he considered superstitions in science, such as the old
legend about the mandrake ; but at the same time he seems
to have adopted and perpetuated the fable of the goose -tree
which bore barnacles from which geese hatched out. He
did not accept this myth without real enquiry and an effort
to obtain first-hand information, and he certainly would
never have written as Gerard wrote that, " he had seen
these trees with his own eyes, and had touched them with
his own hands." Turner's days were the days of herbals,

230 Britain's Heritage of Science

and one cannot, perhaps, give a better description of what
a herbal was than by quoting the title-page of Lyte's (1529-
1607) Herbal, which was mainly a translation from the
French of De L'Ecluse, which was itself a translation from
the " Cruijdeboeck " of Dodoens.

" A niewe Herball, or Historic of Plants, wherein is
contayned the whole discourse and perfect description
of all sortes of Herbes and Plantes ; their divers and
sindry kindes; their straunge Figures, Fashions, and
Shapes ; their Names, Natures, Operations, and Vertues ;
and that not only of those which are here growing in
this our countrie of Englande, but of all others also of
foragne Realmes, commonly used in Physicke. First
set foorth in the Doutche or Almaigne tongue by that
learned D. Rembert Dodoens, Physition to the Emperour,
and now first translated out of Frenche into Englishe
by Henry Lyte, Escuyer."

This herbal went through several editions, but apart
from it Lyte made little contribution to English botany.

One especial merit which Turner had was accuracy of
observation, and a determination to see what he had to
describe. Hitherto, knowledge largely depended upon the
written word of the classical philosophers. Turner pre-
ferred to record his own experiences rather than to repeat
" Pliny's Hearsay." He named many British plants, and,
as Pulteney tells us, " allowing for the time when specifical
distinctions were not established, when almost all the small
plants were disregarded, and the Cryptogamia almost wholly
overlooked, the number he was acquainted with was much
beyond what could easily have been imagined in an original
writer on the subject."

Although other distinguished herbalists who followed hi
Turner's path in the main disregarded his work, there is
no doubt that he started a new era in the study of plants,
and we shall see later he did the same in the study of animals.
Another noted herbalist was John Gerard (1545-1612).
Unlike Turner, he was brought up to be a surgeon, and hi
his youth travelled extensively in Russia, Sweden, Norway,
and other parts of the Continent. To some extent he re-
garded plants from the medical point of view, and in what

The Herbalists 231

was then the village of Holborn, he grew nearly 1,100 various
species of " simples." " The Herball or Generall Historic
of Plantes " is Gerard's claim to fame. Like Lyte's book,
it was based upon the works of Dodoens, and there was a
bitter quarrel as to the exact amount of credit due to the
author of the English edition. Being a physician, Gerard
naturally attached considerable importance to the medi-
cinal side of plants, but he was also a practical gardener,
and the popularity of his book probably depended to some
extent upon the fact that it was the first published in
English of practical use to horticulturists and gardeners.

One last herbalist may be mentioned, Thomas Johnson,
again a medical man with a physic garden of his own. He
was a botanist who travelled in the country inspecting and
recording the local flora, in fact his first publication was
on the flora of the county of Kent. But his claim to
mention depends upon his new edition of Gerard's " Herball,"
which he enlarged, re-edited, and published in 1633. He
added some 800 plants which were unknown, or at any rate
unrecorded, by Gerard, and increased the number of figures
by 700, raising the total to over 2,700. Further and de-
tailed information on herbals may be found in Mrs. Arber's
delightful book on the English herbalists.

At the best, however, these herbals were full of super-
stitious and often nonsensical statements. They must
merely be regarded as catalogues, compilations as a rule
alphabetically arranged, for in the time when they mostly
flourished, plants had not been systematically sorted out.
Their affinities had not been established ; as Professor Green
says, " a herbal may be compared to a dictionary rather than
to any other form of book."

The next outstanding man in the history of British
botany is John Kay (1628-1705). He dealt with both
animals and plants, and what little space we can afford
for biographical details will be found under the chapter
dealing with Zoology. Like Turner and like so many other
botanists, Ray was a clergyman. He marks a new era in
the history of the science of Botany, partly on account of
his efforts towards a natural classification of plants, and
partly on account of his extreme accuracy in the use of

232 Britain's Heritage of Science

words. He was, indeed, as Sir J. E. Smith said, " the most
accurate in observation, the most philosophical in contem-
plation, and the most faithful in description amongst all
the botanists of our own or perhaps any other time." In
his " Methodus Plantarum Nova " (1682), after recognizing
a certain indebtedness to Caesalpino and to Morison, the
first Professor of Botany at Oxford, he expounds his system
of classification and established, for the first time, the dis-
tinction between Dicotyledons and Monocotyledons. Also
here he showed the true nature of buds, and indicated many
of the Natural Orders which systematists now recognize.

Unfortunately, like other botanists of the time, he
retained the unnatural divisions of plants into trees, shrubs,
and herbs. Four years later, Ray published his first
volume of the " History of Plants," and, in 1688, the second
volume, the third and final volume appearing shortly before
his death in 1704. This work contains a description of
nearly 7,000 plants. In 1690 he re-edited the " Catalogus
Plantarum Anglise," which was the first manual of systematic
botany published in England, and was in constant use for
nearly a century afterwards. But Ray was far more than
a systematist ; in fact, he had a very wholesome and proper
disinclination for the founding of new species. As far as
appliances of the times went, he investigated the physiology
and the histology of plants. His researches on the move-
ments of plants and the ascent of sap were as complete as
they could be under the conditions prevailing during his
lifetime. He, with his colleague Willughby, studied the
bleeding of fresh-severed portions of the birch and the
sycamore, both of the branches and of the roots. He was
inclined, though not definitely decided, to accept the sexu-
ality of plants, and supported Grew by his knowledge of
the reproductive process in the animal kingdom. However,
he did not go further than " ut verisimilem tantum
admittamus." But later, he admitted, the male character
of the stamens which after all was giving the whole case
away.

Botany, without any doubt, owes a great deal to Ray.
As Miall has said, " he introduced many lasting improve-
ments— fuller descriptions, better definitions, better asso-

John Ray

From an original portrait
in the British Museum

John Ray, Robert Morison 233

ciations, better sequences. He strove to rest his distinctions
upon knowledge of structure, which he personally investi-
gated at every opportunity." He sought for a natural
system and made considerable steps towards one. In his
classification he relied largely upon the nature of the fruit,
but he insisted also upon the importance of vegetative
habit. He laid stress upon the structure of the seed, appre-
ciated the fact that it not only contained an embryo, but
also the substance we now know as endosperm, but which
he called " medulla " or " pulpa." He made things much
easier for Linnaeus, as did Linnaeus in his turn for
naturalists who now smile at his mistakes. Both were
capable of proposing haphazard classifications, a fact which
need not surprise us when we reflect how much reason we
have to suspect that the best arrangements of birds,
teleostean fishes, insects and flowering plants known to
our own generation need to be largely recast.

A few words must be said about Robert Morison (1620-
1683), a contemporary and to some extent a rival of Ray's,
and whose system of classification for a time, but for a time
only, outshone Ray's. Morison was an Aberdonian and a
Royalist, and having been wounded at the battle of Brigg,
he removed to Paris, the asylum of many of his countrymen.
Here he took up the study of natural science, and ultimately
became the Superintendent of the fine garden of the Duke
of Orleans at Blois. On the death of the Duke in 1660,
Morison returned to England with Charles II., the Duke's
nephew. Charles gave him the title of " King's Physician
and Royal Professor of Botany," and made him Superin-
tendent of the Royal Gardens. Nine years later he was
elected " Botanic Professor " at Oxford, where he remained
until his death.

Ray, who was of humble origin, lived a simple life, and
was emphatically an open air naturalist. Morison, who
frequented courts and the higher walks of university life,
although to a certain extent a field naturalist, more than
Ray, relied on the works of his predecessors. After settling
at Oxford, he gave his whole energies to the production of
his " Historia Plantarum Universalis Oxoniensis." As an
example of what he wished the book to be, he published

234 Britain's Heritage of Science

a monograph on the Umbelliferce, the first British mono-
graph devoted exclusively to the elucidation of a single
large Natural Order. The book was illustrated by some of
the first copper plates which were produced in these islands.
Morison endeavoured to trace the systematic relations of the
members of the family by the aid of a linear arrangement,
and even attempted a genealogical tree. He divided the
flowering plants into fifteen classes; but he was only able
to deal with five of these before his death, though he left
the four succeeding ones finished. The remainder were
completed by Jacob Bobart, the Superintendent of the
Gardens at Oxford.

Morison's families were too few in number, and conse-
quently often overcrowded with what later observation has
shown to be a heterogeneous collection of plants. He
worked from the particular to the general, beginning with
the smallest subdivisions and working up to the larger ones.
Like Ray, he accepted the division of plants into herbs,
shrubs, and trees; but, unlike Ray, he ignored the dis-
tinction between monocotyledons and dicotyledons. He
seems to have been a somewhat selfish man of science,
self-assertive, taking every credit to himself, while allowing
little to his predecessors and contemporaries.

During the latter half of the seventeenth century the
second name of quite outstanding merit in the history of
British Botany — second to that of Ray — is that of Nehemiah
Grew (1641-1712). Like Turner, he was educated at Pem-
broke College, Cambridge, and he subsequently studied
medicine at Leyden, where he took his doctor's degree in
1671. For a time he practised medicine at Coventry, and
later removed to London. He and his contemporary, the
Italian Malpighi, with whom he was always on good terms,
are regarded as the founders of vegetable anatomy. He
was the author of numerous works not all by any means
confined to botany. The greatest of his contributions to
that science was the " Anatomy of Plants," issued in 1684.
Sections I., II., and III. of this volume were second editions
of the " Anatomy of Vegetables Begun." The anatomy
of roots and the anatomy of trunks followed. The fourth
section included the anatomy of leaves, flowers, fruits, and

Nehemiah Grew 235

seeds. The book was richly illustrated. Grew undoubtedly
saw for the first time many structural features in plants,
and although he was not always successful in interpreting
their functions, he added greatly to our knowledge. His
description of the bean-seed might still be used in a modern
Elementary Biology Class. He notes the cotyledons, and
states that the foramen (micropyle) " is not a hole casually
made, or by the breaking off of the stalk; but designedly
formed for the uses hereafter mentioned." He recalls that
when squeezed a bean seed gives rise to many small bubbles
through " the foramen." He notes the radicle, the plumule,
and the two seed-lobes, and is aware that the latter are a
particular kind of leaf — " dissimilar leaves " he calls them,
and he finds that their parenchyma consists of an infinite
number of extremely small " bladders." He also notes
elsewhere that rows or files of " bladders " piled perpendicu-
larly one above each other at times break in upon one another,
and so make a " continued cavity." He recognized and
understood the resin passages in a pine tree, and describes
the medullary rays. He dwells upon the use of hooks in
climbing plants, and the fact that the various whorls of a
flower are arranged alternately. He invented the term
" parenchyma " and others still in use. He was aware of the
existence of stomata, and considers they were either " for
the better avulation of superfluous sap or for the admission
of air." To the flower itself he paid particular attention,
but failed to grasp the use of pollen. He was, however, the
first to point out that flowers are sexual, but unfortunately,
although he is fairly definite on the subject, he made few
experiments. He also described fully and completely the
sporangia of a fern.

Grew, like Ray, was a man of great piety, simplicity,
and undoubted modesty, and he considered that both
" plants and animals came at first out of the same Hand,
and were therefore the contrivance of tRe same Wisdom."
Hence he endeavoured to find analogies and homologies
between animals and vegetables, which later work could
not endorse. Like most of his contemporaries he interested
himself in the ascent of the sap, which he mainly attributed
to capillarity. He stated that the green colour of a plant

236 Britain's Heritage of Science

*

was dependent upon its exposure to air, but he missed the
fact that the green colouring matter is dependent upon light.
He had noticed that many vegetable juices were turned
green by the addition of alkalies, and he considered that some
alkaline properties of the air produced the well-known colour
of leaves. He was groping after the fact that air was necessary
to a plant for its nutrition, though his ideas were by no means
definite. On the whole his greatest contribution to Science
is his discovery of the sexuality of plants; but that is at
least equalled or more than outweighed by his general contri-
butions to our knowledge of the anatomy of plants and to
the science of Botany in almost all its aspects.

The last half of the seventeenth century is distinguished
by the two names of Ray and Grew. Ray, unfortunately,
had no successor. Stephen Hales, with whom we now deal,
was the solitary follower of Grew until comparatively modern
times.

Stephen Hales (1671-1761) was born in Kent and belonged
to the same family as Sir Edward Hales, titular Earl of
Tenterden, the well-known Royalist. He was educated at
Corpus Christi College, Cambridge, where he was admitted
a Fellow in 1602-1603. As a resident of Cambridge he
" scoured the fields for Ray's plants," and worked in the
" laboratory at Trinity College."

In 1708-1709 he became perpetual curate of Teddington,
Middlesex, in which parish, although he held from time to
time other benefices, he mainly resided. Living not far from
Kew he was the friend of the royalties, and although Horace
Walpole called him " a poor good primitive creature," he
was greatly admired and respected by them, and was a
close friend of Pope's, whose will, in fact, he witnessed.

Sir Francis Darwin draws attention to the fact that
Hales' scientific work falls into two main classes : (1) physio-
logical and chemical, (2) inventions and suggestions on
matters connected with health and agriculture. It is with
the former we have mainly to deal.

Hales, as we have pointed out, was the single successor
in the eighteenth century of Nehemiah Grew, but in his
time scientific men were less specialized than they are now,
and Hales was not only a leader in vegetable physiology,

Stephen Hales

Stephen Hales 237

but an active researcher in animal physiology. He, in fact,
introduced into both fields of Physiology the process of
weighing and measuring. His experiments on the loss of
water which plants suffered by evaporation and on the
absorption of water by roots are classic, and still remain
of the greatest importance. His suggestion that the ascent
of the sap is not from the roots only but must proceed from
some power in the stem and branches, has recently met with
a certain amount of corroboration. He introduced a new
method by ever seeking a quantitative knowledge of the
various physiological functions he was enquiring into. He
experimented on the amount of rain and dew on special
areas of the ground, and on the expansive force that peas
exhibit when they absorb water, and explained variations
in pressure from hour to hour on the rate of growth of the
various members of the plant-organism, and all by methods
which are still in use. He was one of the first to oppose
the older views on the circulation of sap — views which had
certainly retarded progress — and at any rate he had some
inkling that air is a source of food to plants. He also had
a clear idea of the importance of scientific knowledge in its
practical application to agriculture. Without any doubt,
the Englishman Hales must be regarded as the founder of
that very important science, Plant Physiology.

Hales was a man of many inventions, and he devoted
his extraordinary ingenuity largely to improving the lot
of oppressed mankind. He invented various artificial
ventilators which were used in granaries, ships, and prisons,
and, so far as one can make out, the health of the prisoners
greatly benefited by the introduction of his appliances.
He also experimented on the distillation of salt water to
make it fresh, on the preservation of various forms of food
for sea voyages, on methods for cleaning harbours, and he
devised an instrument for deep-sea dredging which, together
with a large number of other mechanical contrivances,
occupied his ever active mind.

Hales was evidently a lovable, kindly character, and
without doubt was the greatest physiologist of his age, and
of many later ages.

One other man of science, although not a botanist, must

238 Britain's Heritage of Science

be mentioned here because of his profoundly important
discovery in connexion with the function of leaves. It was
the chemist Joseph Priestley (1733-1804), who, while working
on the investigation of the air, states : "I have been so
happy as by accident to have hit upon a method of restoring
air which has been injured by the burning of candles, and
I have discovered at least one restorative which nature
employs for this purpose. It is vegetation." He records
in 1778 that the green deposit in some vessels which he was
using for his experiments gave off very " pure air," and
discovered that this exhalation was given off when the algse,
as they proved to be, were exposed to sunlight.

Thomas Andrew Knight (1759-1838) was the only out-
standing physiologist between Hales and the rise of the modern
school, and even he was more prominent as a horticulturist
than as a physiologist. He was educated at Balliol College,
Oxford, and, being in the possession of ample means, settled
first in Herefordshire and later at Downton, where he resided
until his death. He made the acquaintance of Sir Joseph
Banks, who was at that time seeking, on behalf of the Board
of Agriculture, certain correspondents who would answer
questions relating to agriculture in their several districts.

Knight was the second President of the Horticultural
Society, which had been founded in 1804. He was elected
in 1810, and occupied the Presidential Chair until his death.

His physiological investigations began with enquiries as
to the circulation of sap, and one of the methods of his
investigations was ringing the trees. He failed, however,
to appreciate the part that the leaf plays in nutrition, and
that the " function of the sap is to supply nutritive materials
to the various tissues and to circulate the manufactured
products of the leaf."

But, as Professor Green reminds us, Knight's work on
the ascent and descent of sap " did much that was not only
instructive for the time," but " was destined to remain with
little modification among the fundamental facts of science."
He made certain anatomical discoveries in connexion with
these physiological experiments, and he incidentally investi-
gated the transpiration or, as it was then called, " the
perspiration," of the leaf, and showed that it was chiefly

Thomas Andrew, T. A. Knight 239

carried on by the under surface. His most important work
was, however, his investigations into the relation of plants
and their growth to the condition of their environment.
He had noticed that, however seeds are placed during
germination, the radicle attempts to descend into the earth
and the shoot attempts to ascend into the air. He used a
water-mill wheel in his garden, a wheel which revolved
rapidly on a horizontal axis on the edge of which he placed
his germinating seeds. He found that the shoots, no matter
how they were pointed at first, gradually turned their points
outwards from the circumference of the wheel, whilst the
radicles grew inwards, so that " in a few days their points
all met in the centre wheel." By this device Knight added
a new apparatus in the investigation of growth. Later he
paid much attention to the tendrils of Ampelopsis and the
clasps of ivy, noting that they showed a tendency to grow
away from the light. Much of his scientific work had
a utilitarian bias, and he published many papers of a strictly
horticultural nature.

In the management of his estate at Downton he experi-
mented continually on the raising of hybrids, and bred a
large number of new varieties of fruits and vegetables, many
of which still bear his name.

Knight was a man of great patience and great perseverance,
and seems to have had a charming personality, warm-hearted
and generous, a little hasty at times, but of great kindness.

Although Linnaeus (1707-1778) does not come within
the scope of this volume, a few lines must be devoted to the
great influence his views had on English thought. Without
being a great investigator he remodelled the art of description.
He introduced new and concise terms. He re-established
the binomial nomenclature of plants, and he devised an
artificial method of classification by means of which a com-
petent botanist could determine the genus and species of
almost any flower. But he was more of a co-ordinator than
an investigator. He added few new facts to science, and,
as Professor Green states, " we cannot find that either he
nor any of his immediate pupils made a single discovery of
any importance." His great talents lay in organization. He
had a gift for sorting out things and putting them into what

240 Britain's Heritage of Science

he considered the right place. His sexual system of classifi-
cation was, as he himself felt, a merely temporary one, but
it caught on and for fifty years did much to hinder the pro-
gress of real scientific enquiry into the natural relationships
•of plants inter se.

His name leads us on to Sir J. E. Smith (1759-1829), a
friend of Sir Joseph Banks. In fact it was at his breakfast
table that the news came that the mother of Linnaeus had
recently died, and that his collections were offered for sale.
Smith, who was a man of considerable means, purchased
the collections for a thousand guineas, and although the
Swedish Government are said to have sent a man-of-war to
retrieve them whilst they were yet at sea, they eluded the
pursuit — if there was a pursuit — and were landed in England
and arranged as speedily as possible by Smith, with the aid
of Sir Joseph Banks and his librarian Dryander. This
episode decided Smith to abandon the study of medicine
and take up that of botany, and to him the foundation of
the Linnsean Society is due. He was the author of many
books, and in 1790 he collaborated with Sower by in the
production of Sowerby's " English Botany," which extended
over thirty-six volumes, and in which he was responsible for
practically all the letter-press. Another notable work of
his, published in 1807, was an " Introduction to Physio-
logical and Systematic Botany," and the last seven years of
his life he devoted to the " English Flora."

We now turn to a class of men of science in which England
has always been pre-eminent — the scientific explorer and
collector.

One of the earliest of these, Sir Hans Sloane (1660-1753),
started life as a doctor, having studied medicine at Paris and
Montpellier. He was well acquainted with the leading men
of science of his period, and for a time lived with Thomas
Sydenham. His great opportunity came in 1687, when he
accompanied, as physician, the Duke of Albemarle, Governor
of Jamaica, to the West Indies. Owing to the death of the
Duke, his stay in the islands was curtailed, but he came
back in 1689 with 800 species of plants and settled down to
medical practice. He became Secretary to the Royal Society
in 1693, and, while he was busily at work on his collections,

T. A. Knight, Sir Joseph Banks 241

found time to contribute a number of papers to the Philo-
sophical Transactions.

On the death of Sir Isaac Newton he followed him as
President of the Royal Society, and occupied the chair for
twenty-eight years, until 1740. Perhaps his greatest con-
tribution to botany was in connexion with the Physic
Garden of Chelsea. He had purchased the manor of that
village in 1712, and on retiring from practice settled on his
estate. This included the site of a " Physic " garden estab-
lished, in 1673, by the Apothecaries' Society, and Sloane
handed, in 1722, the fee simple of the property to that body,
subject to certain conditions. His name is commemorated
on the Cadogan Estate in the West End of London by Sloane
Square and Hans Place.

A second explorer, " the greatest Englishman of his time,"
traveller and prominent collector, was Sir Joseph Banks
(1743-1820), who was educated both at Harrow and Eton.
At school he was so immoderately fond of play that his
masters found great difficulty in fixing his attention on his
studies, but at the age of fourteen, impressed by the beauties
of flowers in the country lanes, he decided to study botany,
and probably his real education was largely due to the women
who were then, as they are now, collecting " simples " for
druggists' shops. At Oxford, where he found no lectures were
being delivered on his favourite subject, he obtained per-
mission to procure a teacher to be paid by the students, and
coming over to Cambridge he brought back with him to his own
university Israel Lyons, the astronomer and botanist. I wonder
if any student has ever attempted such an enterprise since !

Banks was a wealthy man and was able to indulge
his passion for travelling. His first journey was to New-
foundland, and after his return, via Lisbon, he came across
Dr. Daniel Solander, the faithful pupil of Linnaeus, who
subsequently accompanied him in his voyage round the
world, for Banks left England in August 1768 on Captain
Cook's Endeavour. The scientific part of the expedition was
financed by Banks, and he was accompanied not only by
Dr. Solander but by two artists and two attendants. It
would take too much space to dwell upon that remarkable
voyage, Banks was collecting not only plants, but animals,

Q

242 Britain's Heritage of Science

and noted, as an ancient writer said, " ye beastlie devices
of ye heathen." At a spot they christened Botany Bay,
owing to the wealth of plant life in the district, kangaroos
were observed for the first time.

The Endeavour returned in the spring of 1771, and Banks
very shortly afterwards made arrangements (which ulti-
mately fell through) to accompany Captain Cook on a second
voyage in the Resolution. Being disappointed over this
expedition, Banks visited Iceland with his scientific staff
and Dr. Solander. This was the last of his travels.

He became President of the Royal Society in 1778, and
held that distinguished office until his death. For a time his
reign was a troubled one. The secretaries had assumed, as
secretaries often do, a power which belonged to others, and
Banks was determined to put this right. The dissensions
that followed led to a secession of several members, but the
majority remained and harmony was once more restored.

The contributions that Banks made to science by personal
investigation were comparatively few, but he was a great
patron of Natural History, and although he wrote little,
he was the cause of much writing by others. He made his
collections accessible to men of science, and his house in
Soho Square was a rallying spot for those interested in
Natural History. His library was one of the finest then
existing, the catalogue of it by Dryander exists in five
volumes. The library is still kept in a room by itself in the
British Museum. Although apparently a bit of an autocrat,
he was a generous and far-seeing man, and those who knew
him best undoubtedly loved him most.

The Linnsean system was destined to disappear, and
during the first decades of the nineteenth century it was
being gradually replaced by a more natural and scientific
scheme of classification. In this, England practically led
the way, and, indeed, Professor Green tells us that with
Robert Brown began " a long line of taxonomists of the
greatest brilliance, who not only outshone all their prede-
cessors, but carried the nation's prestige in botany to a pitch
that had not been reached even under the influence of Ray."

Brilliant and stimulating as were the speculations of
the French School from De Jussieu to De Candolle, the

Sir Joseph Banks, Robert Brown 243

English were at least their levels in the study of the
herbarium. Where they outshone all other nations was in
their world-wide explorations, their vast collections of extra-
European plants, which laid the foundation of the science
of geographic botany and afforded the material which was
destined to form the basis of the speculations as to the
" Origin of Species " which were so prominent a feature in
the latter part of the nineteenth century.

Robert Brown (1773-1858), one of the most brilliant
men of science Europe has produced, was the son of the
Episcopalian minister in Montrose. He was educated partly
at Aberdeen and partly at Edinburgh, where, for the first
time, he showed the interest which never afterwards failed
him in the science of botany. In 1795 he obtained a double
commission as Ensign and Assistant Surgeon in the Fife-
shire Regiment of Eencible Infantry, and proceeded to
Ireland. In 1798, being sent to England on a recruiting
service, he became the friend of Sir Joseph Banks, who
was destined to help him in no common measure. It was
owing, indeed, to Banks that he resigned his commission and
started on his memorable voyage to Australia and Tasmania.
He left Portsmouth in 1801 under the command of Captain
Flinders, and was away about four years. The South Coast
of Australia, the tropical part of the East Coast and part
of the North were explored before Flinders was compelled
to return to England by the bad state of his ship. The
botanists, however, remained in Australia for another year
and a half, and extended their investigations to Tasmania
and other islands. Altogether about 4,000 species of plants
were collected, and on his return to England in 1805 these
great collections, added to those which Sir Joseph had
brought back from Captain Cook's circumnavigation of the
globe, and those due to other explorers, were now thoroughly
worked out by Brown. As Asa Gray remarks :

" It was the wonderful sagacity and insight which
he evinced in these investigations which, soon after his
return from Australia, revealed the master mind in
botanical science, and ere long gave him the position of
almost unchallenged eminence, which he retained without
effort for more than a century."

Q2

244 Britain's Heritage of Science

The result of these researches was the work " Prodromus
Florae Novae Hollandiae et Insulse Van Dieman," a work
marked by singular accuracy of detail set forth in precise
and clear language ; it showed, moreover, a profound mastery
of the principles of classification.

Another important publication of Brown was his mono-
graph on the Proteacece, which contained one of his first great
contributions to Histology, namely, that dealing with the
structure of the seed. Brown was also the first to recognize
the true nature of the seed in Gymnosperms. He paid
much attention to the structure of the flower and the
methods of pollination, especially in the Natural Orders
Orchidece and Asclepiadece. In fact, so important did his
work appear to foreigners, that Humboldt dedicated his
" Synopsis Plantarum Orbis novi " to him in the following
words : " Roberto Brownio Britanniarium glorias atque
ornamento." We have no space to follow further his tireless
work on classification.

Brown, who had succeeded Dryander as librarian to
Sir Joseph Banks in 1810, at the latter's death in 1820
succeeded to the use and enjoyment of his collections and
library, together with the house in Soho Square, where
for nearly sixty years he had pursued his investigations.
More than once during his life he had been offered professor-
ships, but he was essentially a researcher, and preferred
the quiet of Soho Square, which has been so well described
by Dickens in the "Tale of Two Cities." Indeed, the
character of Dr. Manette might almost have been drawn
from Brown, for, as a friend wrote of him, " I loved him for
his truth, his simple modesty, and, above all, for his more
than woman's tenderness. Of all the persons I have known,
I have never known his equal in kindliness of nature."

Before passing on, one must not omit to mention that
in his monograph on the Orchidece Brown first announced
the discovery of the nucleus in the vegetable cell. He is
also the discoverer of the so-called Brownian movement —
an irregular trembling motion of very small particles sus-
pended in liquids — which becomes visible under the micro-
scope, when high magnifying powers are applied. It is
connected with the thermal motion of the molecules of

John Lindley 245

the liquids, and has gained some importance in recent
years.

Although Brown did much to undermine the Linnaean
system, it was not by a frontal attack so much as by
courteously and consistently ignoring it.

John Lindley (1799-1865) took more direct action. Lind-
ley was born near Norwich, where he was educated. His
father was a nurseryman, and throughout his life Lindley
showed a particular interest in all horticultural matters. In
1819 he went to London, and shortly afterwards was
appointed Garden Assistant Secretary to the Horticultural
Society, and in 1830 Secretary to the Society. It was his
efforts, combined with those of Bentham, which rescued the
Society from financial disaster, and organised the very
successful series of exhibitions of flowers and vegetables,
the first " flower-shows " recorded in Great Britain.

In 1829 he was elected Professor of Botany at University
College, London, and was the first occupant of that Chair.
His lectures were singularly concise and clear, and attracted
large classes. Throughout his life he was a constant advocate
of a natural system of classification as opposed to the
artificial one of Linnaeus, and in 1829 he published a " Synopsis
of the British Flora," which was one of the first attempts
to arrange British plants on a basis of natural affinity. The
following year, in an Introduction to the " Natural System
of Botany," he put forward, tentatively, his natural classifi-
cation. He helped Loudon to bring out his " Encyclopaedia
of Gardening," wrote much for the " Penny Encyclopaedia,"
collaborated with Hutton in the " Fossil Flora of Great
Britain," and with Sir Joseph Paxton in a work entitled
" Paxton's Flower Garden," and in 1821 started the well-
known " Gardener's Chronicle," which he edited for twenty-
five years.

Although experts do not admit that Lindley achieved
any permanent success in framing his classification, he was
undoubtedly a great taxonomist. He was celebrated for the
completeness of his descriptions of the several Natural Orders
and valued for his clear discussions on their inter-relation-
ships. He was an extremely hard worker, and took a large
share in administrative work; towards the end of his life

246 Britain's Heritage of Science

he acted for the Government in the preparation for the
Great Exhibition of 1851, and undertook the entire charge
of the Colonial Department in the following Exhibition of
1862. Lindley's only son is the present Lord Lindley.

Born in the saifie neighbourhood and educated at the
same school a few years before Lindley, Sir William Jackson
Hooker (1785-1865) was another example of a biologist
who commenced his scientific life as a traveller. In 1809,
on the advice of Sir Joseph Banks, he visited Iceland, but
unfortunately lost his collections by the burning of the ship
on the return voyage. He wished to accompany Sir Robert
Brownrigg, the recently appointed Governor of Ceylon, but
the disturbed state of the Island prevented his carrying
out his intentions.

In 1820 he accepted the Professorship of Botany at
Glasgow, where he was singularly successful as a teacher.
In 1841 he was appointed Director of the Royal Gardens at
Kew, and we shall have to consider later his work there.
He had always been a great collector, and his herbarium,
which was far the richest ever accumulated in his lifetime by
any one man, was bought by the nation after his death.
Though much engaged in official duties, he was, neverthe-
less, a great writer, and produced over one hundred memoirs
and volumes on Economic and Systematic Botany. He was
particularly happy in his relations with the officials in the
Greater Britain beyond the seas, and inaugurated a series
of Colonial floras, which have proved of great value. He
was one of those men always anxious to help others, and he
readily placed his knowledge and his collections at the
disposal of younger men. So busy a life left little time
for society, but Darwin records " his remarkably cordial,
courteous, and frank bearing."

Another contemporary was George Bentham (1800-1884),
a nephew of Jeremy Bentham. He was brought up abroad,
and had a wide acquaintance with the flora of Southern
France. In 1821 he returned to England, and at once made
the acquaintance of the leading botanists of the time, and
very soon took a prominent position himself as a systematic
botanist. He contributed the " Flora of Hong Kong " and
the " Flora Australiensis " to Sir William J. Hooker's

W. J. Hooker, G. Bentham, J. D. Hooker 247

Colonial Floras. But his great work was the " Genera
Plant arum," in the execution of which he was associated with
Sir Joseph D. Hooker. One must not forget to mention
his " Handbook of the British Flora," published in 1858.
He was a man endowed with a gift of accuracy, discrimina-
tion and precision, and with infinite powers for hard work.
He handled collections of plants from every quarter of the
globe, and, as one of the most distinguished contemporaries
remarked, he possessed " an insight, of so special a character
as to be genius, into the relative value of characters for
practical systematic work — a sure grading of essentials and
non-essentials."

Bentham was an untiring worker, and it was character-
istic of him that having finished, after a year's incessant
work for the " Genera Plantarum," whose publication
extended from 1862-1883, the Orchidacece on a certain
Saturday afternoon, he bade the attendant at the Herbarium
to bring down the material for commencing the much more
difficult group of the Grasses. It is impossible here to enu-
merate the numerous papers and memoirs which Bentham
published, and one can only sum him up by saying that he
was one of the greatest systematic botanists who ever lived ;
his colleague, Hooker, said of him " There is scarcely a
Natural Order that he did not more or less remodel."

A contemporary of Bentham and the vounger son of Sir
W. J. Hooker was Sir Joseph Dalton Hooker (1817-1911).
The younger Hooker is another example so common in
British biological science of men who approach their subjects
through extensive travel. Inspired by his father he, as a
boy, took an intense interest in botanical research, but,
like all young men, he was eager to travel, to see the world.
He qualified as a Doctor of Medicine at Glasgow, and was
delighted when Sir James Clark Ross offered to take him
as assistant surgeon and analyst on his ship the Erebus to
the Antarctic. When the expedition returned in 1843,
Hooker devoted himself to publishing the botanical results
of the voyage. These filled six quarto volumes.

At about this date the intercourse between Darwin and the
younger Hooker became closer, and there was a constant inter-
change of correspondence between the two contemporaries.

248 Britain's Heritage of Science

Hooker's researches, especially on the flora of the Gala-
pagos, had convinced him that there was an evolution in
space. On the one hand he found that the plants of
neighbouring hills, though related, differed in detail; on
the other hand, identical species were often found on hills
separated by many thousand miles of ocean. Hooker was
the first to whom Darwin confided his theories of natural
selection, and he read for his friend the proofs of the first
sketch of the " Origin of Species." In fact, Darwin wrote
to him " for years I have looked on you as a man whose
opinion I valued on any scientific subject more than anyone
else in the world."

In 1845 J. D. Hooker was appointed Botanist to the
Geological Survey, and for a time turned his attention to
fossil botany. But his love of travel was not yet sated,
and in 1847 he started to explore the Himalayas. He spent
part of two years in exploring Sikkim, and for a time was
imprisoned. He also explored part of Nepal, and visited
territory which has not even yet been re-investigated. He
penetrated some way into Tibet, and one afternoon at his
house in Sunningdale he received a telegram from the Lhassa
Expedition of 1903, stating that they had got as far as he had
previously penetrated, and congratulating him upon the
usefulness of his survey. Having explored Eastern Bengal
and the Khasia Hills, he returned to England in 1851, and
in 1855 he was appointed Assistant Director to his father at
Kew, and ten years later succeeded his father as Director.

On his return form India, he immediately commenced,
in conjunction with Thomas, the first volume of the " Flora
Indica," which, however, also proved to be the last, as it
was planned on too ambitious a scale. In 1860 he visited
and examined considerable areas of Syria, and about this time
he was contemplating his celebrated " Genera Plantarum."
But the call of the world still held him, and in 1871 this
indefatigable traveller, accompanied by John Ball and Maw,
made an expedition into Morocco. They were the first
Europeans to ascend the Tagherot Pass, nearly twelve
thousand feet high.

In 1873 Hooker became President of the Royal Society,
and he made a real effort to bring that Institution into closer

Sir Joseph Dalton Hooker 249

touch with the social life of the community. He was suc-
cessful in raising the sum of £10,000 to aid the somewhat
exiguous resources of the Society. In 1877 he obtained
leave of absence to visit the Rocky Mountains of Colorado
and Utah, and added much to our knowledge of the fossil
flora of those districts, and later he returned to his first love
and made a determined effort to complete his " Flora of
British India," which was accomplished in seven volumes
during the next fourteen years. In 1885 he retired from the
Directorship of Kew, and was succeeded by Sir William
Thiselton-Dyer, but he never ceased working.

Hooker was the recipient of numerous honours, including
the O.M., which was personally presented to him at Sunning-
dale, to which village he had retired, on behalf of King
Edward VII. on his ninetieth birthday.

Hooker stands out as the greatest authority the world
has yet produced on the subject of the Distribution of Plants ;
although he did much other work, this alone confers on him
immortality.

Hooker was capable of enduring great physical fatigue,
capable of working continuously with very short intervals of
sleep. Somewhat highly strung he disliked public functions,
though when forced to do so he could make an eloquent and
stirring speech. He was extremely kind and courteous, and
always ready to help the younger men. He retained his
faculties to the last, and continued to work to the end of his
long, laborious, and successful life.

We have seen that most of the progress of the physiology
of plants was due to British workers; but naturally in the
last quarter of the eighteenth century Great Britain had to
some extent remained isolated from the science of the
continent, and the currents of botanical thought flowed at
somewhat different angles on the two sides of the Channel.
We shall see later how Huxley inaugurated a new departure
in the teaching of biology, and with him came the laboratory.
Hitherto the botanists had been content with their botanic
gardens, their herbaria, and with a few roughly devised
physiological instruments. With " the coming of the labora-
tory," however, things altered. Huxley had round him an
ardent body of young workers. His first demonstrators

250 Britain's Heritage of Science

were Michael Foster, Ray Lankester, and Rutherford, and
later Newall Martin (who collaborated with his chief in the
production of the " Elementary Biology "), Thiselton-Dyer,
and Vines. The coming of the laboratory was slower at
the Universities, but with the arrival of Foster at Cambridge,
and the return for a time of the old Cambridge men, Martin
and Vines, laboratory instruction became part of the normal
course.

The modern study of Cryptogamic Botany in England
may almost be said to begin with the works of Miles Joseph
Berkeley (1803-1889). Like so many English botanists he
was in Holy Orders. Coming from Oundle and Rugby to
Christ's College, Cambridge, he came under the influence of
Henslow, and took his degree in 1825. At first he worked
on the Algae, but in 1836 he published, in connexion with
Smith's " English Flora " the section which dealt with the
fungi, and this was the earliest of his many contributions
on this group. He was the first to throw light upon the
fungoid organism Phytophthera infestans, which caused the
potato disease connected with the appalling famine in Ireland
in 1846.

Between 1844 and 1856 his " Decades of Fungi " were
published and were amongst the most conspicuous of con-
temporary publications on this subject. Berkeley paid
particular attention to the diseases of plants, and contributed
a series of articles to Lindley's newly-established " Gardener's
Chronicle." For many years he was the authority at Kew
on Cryptogamic Botany. He described the fungi collected
by his fellow-collegian, Darwin, on the Beagle, and his classical
knowledge was of great use to Bentham and Hooker in their
" Genera Plantarum." His large collections of algae were left
to Cambridge, whilst his fungi went to Kew.

During his lifetime he was easily leader in the taxonomy
of the subject, and he may almost be said to have started
a new line of research. His most distinguished successor
was Marshall Ward, who will be dealt with more fully under
the Cambridge School.

The great majority of the earlier botanists hitherto
mentioned li ved and worked in London, but a small minority
carried on their researches in country houses or, more often,

M. J. Berkeley, W. Sherard, C. G. Daubeny 251

in country parsonages. But there are other centres of
activity in England, though none of them, till the re-awakening
of science at the end of the nineteenth century, produced
men of very outstanding talent.

We have seen that Morison was the first Professor of
Botany at Oxford — he was appointed Professor in 1669 —
although when he was appointed the Botanic Garden at
Oxford had already been in being for thirty-seven years.
His successors, however, were people of comparatively little
importance ; the Professorship was always very inadequately
endowed. In 1728 William Sherard (1659-1728), who was
more of a patron of science than a man of science, left by
will a sum to re-endow the Professorship, which was now
named after him, and this was at first occupied by the German
Dillenius (1687-1747), who was undoubtedly one of the great
botanists in Great Britain during the eighteenth century;
but his work, though painstaking and laborious, showed little
originality and insight. His knowledge, however, was great,
and was recognized by his contemporaries at the time.
Perhaps his greatest work was the " Historia Muscorum,"
which appeared in 1741. As Professor Green says, "it is
a work of colossal labour, but it is impossible to avoid a
certain feeling of disappointment with the " Historia," not that
it was not good but that it might have been so much better."
Dillenius was, however, conservative in his thought, and a
man without a great faculty for new enterprise. After his
death, botany again fell under a cloud at Oxford, and for
a time at any rate Cambridge took the lead.

One must, however, mention Sibthorp (1758-1796), who,
always impressed with the relation of his science to agri-
culture, founded the Professorship of Rural Economy which
now bears his name.

In 1834 the School of Botany at Oxford woke up. Pro-
fessor Charles Giles Daubeny (1795-1867) of Magdalen College
was, as men of science were in those days, very versatile, he
was almost equally distinguished as a geologist^ a chemist,
and a botanist. And again, after the manner of those times,
he did not hesitate to hold contemporaneously three pro-
fessorships. For in 1822 he became Professor of Chemistry,
and only resigned it in 1855, and in 1834 Sherardian Professor

252 Britain's Heritage of Science

of Botany, and in 1840 Sibthorpian Professor of Rural
Economy. It is not our intention in this volume to deal
with agriculture, but one might at least indicate that he
was one of the earliest to throw light on the principles involved
in the rotation of crops, to investigate the constituents of
plant ashes, to show the difference between " the total amount
of the salts contained in the soil and the amount available
for use by the plant," and above all he had a keen appreciation
of the part that the fungi play in diseases of plants.

Daubeny remodelled the beautiful Botanic Gardens at
Oxford and founded the Botanic Museum. He was a keen
supporter of Darwin's views of Natural Selection, and spoke
strongly in their favour at the meeting of the British
Association in 1860.

If we now turn to Cambridge we again find no name of
absolutely outstanding merit until the revival of science at
the end of the nineteenth century.

A few words should, however, be said about the second
Martyn, who succeeded his father to the Professorship in
the year 1761. Thomas Martyn (1735-1825) was a parson,
and in 1762 he was elected to succeed his father to
the Chair of Botany, which he held for the astonishing
period of sixty-three years. He was, however, as professors
were apt to be in those times, largely non-resident, and he
ceased lecturing altogether in 1796. But for many years
before that date he had been out of residence, and only
returned from time to time to what was obviously an
uninterested audience.

Henslow (1796-1861), who succeeded Martyn, was a
different kind of man, and did much to encourage the advance
of science in many directions. For a time he held the Chair
of Mineralogy, having been appointed at the age of twenty-
six, together with the Chair of Botany, but he devoted
most of his energy to the latter subject, and his lectures
attracted large audiences. He used many illustrations, and
for the first time introduced what was later destined to
develop into practical laboratory work. He reorganized
the Botanic Garden, and during his time it was moved to
its present site, and for the first time organized systematic
excursions in the neighbouring country. His success in

T. Martyn, H. Marshall Ward 253

interesting Suffolk farmers in his parish in the application
of Botany to Agriculture was notable. He is renowned
not for any strikingly remarkable original contributions to
science, but for taking a leading part in reorganizing the
scientific spirit of Cambridge.

The only other botanist of eminence connected with
Cambridge was Professor Marshall Ward (1854-1906). He was,
in a way, a successor of Berkeley, and although he always
was very nervous of the encroachment of what is known as
" technical research " on the purer kind, his own researches
were without exception of practical utilitarian value. Ward,
like Berkeley, was educated at Christ's College, and afterwards
studied in Germany. For a time he was teaching at Owens
College, Manchester, and later he was Professor of Botany
in the Forestry Department of the Royal Engineering College
at Cooper's Hill; he was appointed Professor at Cambridge
in the year 1895. One of his earliest researches involved a
visit to Ceylon, where he investigated the life-history of the
fungus that attacks the leaves of the coffee plant, which in
fact destroyed the coffee trade of that island. He worked
out the life-history of this pathogenic fungus, and was largely
instrumental in inducing the planters to take up the planting
of tea.

Throughout his life Ward was largely occupied with the
study of bacteria and fungi, to which he contributed much
of first-rate importance. During his professorship the
present School of Botany was erected and equipped, and
at the time of its erection it was, and still is, second to none
in Great Britain in size and completeness of equipment.

The history of Botany in Scotland and in Ireland
shows, as at first was the case in Cambridge and Oxford, no
particularly outstanding names. The University Chair in
Edinburgh was founded in 1695, and was first filled by James
Sutherland (1639-1719), who, in 1667, had succeeded in estab-
lishing and stocking a small botanic garden. At Glasgow,
from the year 1719, Botany no longer had a distinct professor,
the subject being taught by the Professor of Anatomy, a
separate Chair reappearing only in the year 1818. The first
occupant of this double chair was Thomas Brisbane, a man
who entertained so strong a dislike to dissection, that it is

254 Britain's Heritage of Science

believed he never taught anatomy at all. It cannot be said
that his teaching in botany in any way compensated for this
silence in anatomy. The curious conjunction of the two
professorships did not produce anyone of any particular
eminence in botanic science. B. K. Greville (1794-1866),
who held no official post, was, however, establishing a great
reputation for his knowledge of cryptogamic botany, in
which subject he is said to have done more than any botanist
of his times.

Hooker, whose work is mentioned elsewhere, succeeded
Graham as Professor of Botany at Glasgow, and for a time
the chief activity in this science was in the western rather
than the eastern university.

On Graham's succeeding to the Chair in Edinburgh,
Botany again revived, for he was an able lecturer, a man
of great activity, and he organized botanical excursions for
his pupils.

He was succeeded by J. H. Balfour (1808-1884), a brilliant
teacher and a most genial man, called by his pupils " woody
fibre." He was known best, perhaps, as a teacher than as
an investigator, and, as was usual during the times in which
he lived, his researches were largely of a systematic kind. He
was the first, however, to introduce the use of the microscope
into the Class-room.

The Irish records of botanical research are at least as
scanty as those of Scotland. The first authentic authority
on plants was Caleb Threlkeld (1676-1728), but his book,
under the ambitious title of " Synopsis Stirpium Hiberni-
carum," was little more than a herbal.

A lectureship was established at Trinity College in 1711
and associated with it was a small Physic Garden. In 1786
the lecturer, who was at that time Edward Hill, was raised
to the status of a professor. His chief work seems to have
laid in the botanic garden and in starting the herbarium.
Amongst his successors perhaps Professor -William Allman
should be mentioned. He was succeeded by a succession
of able men, but none of them pre-eminently able.

This brief survey of the history of British Botany shows
that there is ever a steady current of research and investigation
going on in these islands and with here and there a temporary

Summary 255

lull, men of world-wide importance were constantly emerging
from the high level of their contemporaries. Hales, no doubt,
laid the foundation of scientific plant physiology, even Sachs
has said that his " Vegetable Staticks " " was the first com-
prehensive work the world had seen which was devoted to
the nutrition of plants and the movement of their sap . . .
Hales had the art of making plants reveal themselves. By
experiments planned and cunningly carried out he forced
them to betray the energies hidden in their apparently
inactive bodies." Grew was one of the earliest and greatest
investigators of plant anatomy, and, as we have said above
may be regarded as joint founder with Malpighi of the science
of vegetable anatomy. Robert Brown was regarded by his
contemporaries as the first botanist of his age, and he it was
who for the first time took into account the development
of plants as well as the structure of the mature and adult
forms. He and John Lindley did much to establish a
natural system based on the widest investigation possible
in their times. Sir Joseph Hooker may almost be said to
be the inventor of phyto-geography. Professor Bower writes
of him : — " and so we have followed . . . this great man
into the various lines of scientific activity which he pursued.
We have seen him excel in them all. The cumulative result
is that he is universally held to have been, during several
decades, the most distinguished botanist of this time. He
was before all things a philosopher. In him we see the
foremost student of the broader aspects of plant-life at the
time when evolutionary belief was nascent."

In the Stewarts' time, as we have seen, British science
led the world, and ever since our men of science have held
their own in comparison with the men of science of the
nations which can boast of an old civilization and far
surpassed, both in amount and in originality, that of nations
whose civilization only dates back to a few hundred years.

256 Britaiirs Heritage of Science

CHAPTER X

ZOOLOGY

IN 1544 William Turner, the leading naturalist of his
time, published his " Avium Praecipuarum quarum apud
Plinium et Aristotelem mentio est, brevis et succincta
historia," dedicated to Edward Prince of Wales, after-
wards Edward VI. Turner had been educated at Pembroke
College, Cambridge, where he knew Latimer and learned
Greek from Ridley. He travelled much abroad, and became
an M.D. of Ferrara and subsequently of Oxford. Later in
life he was ordained, and in 1550 he was appointed Dean
of Wells, a post he was compelled to quit on the accession
of Queen Mary. His business in life was theological con-
troversy and he wrote many polemical works, but his
pleasure was in natural history. He contributed a letter
on British fishes to his friend Conrad Gesner, with whom
he had worked at Zurich, and with whom he constantly
corresponded. As an example of the zoology available in
the Great Eliza's times, we may quote Turner's description
of the grouse.

" Of the Lagopus" from Pliny.

" The Lagopus is in flavour excellent, its feet shaggy
as in a hare have given it this name. Otherwise, it is
white, in size as the Columbi; it is not eaten except in
the land of which it is a native, since it is not tameable
while living, and when killed its flesh soon putrefies.
There is another bird of the same name, differing but
in size from the Coturnices, most excellent for food with
yellow saffron sauce. Of this Martial makes mention
in the following verse : —

"If my Flaccus delights in the eared Lagopodes."

W. Turner, E. Wotton, John Gains 257

Although this may seem to indicate that Turner was a
mere translator and compiler, this is not the case. As
Mr. A. H. Evans tells us :

" While attempting to determine the principal kinds

of birds named by Aristotle and Pliny, he has added

notes from his own experience on some species which had

come under his observation, and in so doing he has

produced the first book on Birds which treats them in

anything like a modern scientific spirit . . . nor is

it too much to say that almost every page bears witness

to a personal knowledge of the subject, which would be

distinctly creditable even to a modern ornithologist."

A contemporary of Turner's, Edward Wotton (1492-

1555), born at Oxford and elected a Fellow of Magdalen,

travelled for several years in Italy. He took his M.D. at

Padua, and later held high office in the College of Physicians,

and has been described as " the first English Physician who

made a systematic study of natural history." His book,

"De Differ entiis Animalium," published two years before

Turner's Historia and dedicated to the same patron, acquired

a European reputation. The copy of this book, a fine folio,

in the British Museum, is said to be " probably unsurpassed

in typographical excellence by any contemporary work."

"De DifFerentiis Animalium" was deservedly praised by

contemporary writers for its learning and for the elegance

of its language.

Dr. Caius (1510-1573), in his terse style, wrote "De
Canibus Britannicis libellus," 1570, and this was " drawne
into Englishe " under the name " Of Englishe Dogges," by
Abraham Fleming in 1576, and published in London. Caius
wrote his little book as a contribution to Conrad Gesner's
" History of Animals," but owing to Gesner's death it was
not incorporated in that work. For, from the sixth year of
Henry the Eighth until the death of Queen Elizabeth, all
the learned men of Europe who were interested in Nature
turned to Gesner, the incomparable naturalist of Zurich
(1516-1565), amongst whose many works of great import-
ance the stupendous " Historia Animalium " is perhaps the
most remarkable.

In the year 1607, Edward Topsell, a member of Christ's

8

258 Britain's Heritage of Science

College and, in the matter of livings, somewhat of a pluralist,
published, under the title " The Historie of Foure-Footed
Beastes," an abstract of Gesner, and in the next year followed
it up with " The Historie of Serpents," both illustrated with
charmingly quaint, if inaccurate, woodcuts. Topsell had,
what the modern zoologist must have (but the possession
in his time was less common), a sound knowledge of
German, and to this knowledge his books owe much.
These works give us a fair idea of what the educated in those
days knew of zoology in all its aspects, and that these aspects
covered a far wider area than, with the present expansion
of knowledge, we can now contemplate under this single
science, is shown by the title-page to TopselTs magnificent
quarto volume :

" The History of Foure-Footed Beastes. Describing

the true and lively figure of every Beast, with a discourse

of their severall Names, Conditions, Kindes, Vertues (both

naturall and medicinall), Countries of their breed, their

love and hate to Mankinde, and the wonderful worke of

God in their Creation, Preservation, and Destruction.

Necessary for all Divines and Students, because the

story of every Beast is amplified with Narrations out

of Scriptures, Fathers, Phylosophers, Physitians, and

Poets : wherein are declared divers Hyerogliphicks,

Emblems, Epigrams, and other ,good Histories, collected

out of all the Volumes of Conradus Gesner, and all other

Writers to this present day. By Edward Topsell.

London, Printed by William Jaggard, 1607."

Falconry also played a part in the Zoology of the later

Tudor times. During the reign of Queen Elizabeth this

sport was " much esteemed and exercised." People of all

classes eagerly took part in it. To quote Mr. Harting :

" The rank of the owner was indicated by the species
of bird which he carried. To a king belonged the ger-
falcon; to a prince, the falcon gentle; to an earl, the
peregrine; to a lady, the merlin; to a young squire,
the hobby ; while a yeoman carried a goshawk ; a priest,
a sparrowhawk; and a knave, or servant, a kestrel."
The sport was, however, expensive, for it took much
time and devotion to train the birds. The falcon, in those

E, Topsell, F. Willughby, J. Ray 259

times, as the flying machine is in ours, was in the air, and
just as one now hears our undergraduates discussing carbu-
retters, air-locks, sparking-plugs, and various vintages of
petrol, so in the times of Queen Elizabeth, the keen young
men of Shakepeare's Plays discussed the various kinds of
hawks and their habits.

In our last chapter we have sketched the contribu-
tions which Ray had made to the science of Botany ; but
he has further claims on our regard. He and Francis
Willughby, both of Trinity College, Cambridge, attacked
similar problems in the animal kingdom. Wiilughby was
the only son of wealthy and titled parents, while Ray was
the son of a village blacksmith. But the older universities
are great levellers, and Ray succeeded in infusing into his
fellow student at Cambridge his own genuine love for
natural history. With Willughby, he started forth on his
methodical investigations of animals and plants in all the
accessible parts of the world. Willughby died young and
bequeathed a small benefaction and his manuscripts to his
older friend. After his death, Ray undertook to revise and
complete his " Ornithology," and therein paid great attention
to the internal anatomy, to the habits and to the eggs of
most of the birds he described. Further, he edited Willughby 's
"History of Fishes," but perpetuated the mistake of his
predecessors in retaining whales in that group. In rather
rationalistic mood, he argues that the fish which swallowed
Jonah must have been a shark. Perhaps the weakest of
their three great histories — "The History of Insects" — was
such owing to the fact that Ray edited it in his old age. The
Ray Society for the publication of works on Natural Science
was founded in his honour in 1842.

Robert Hooke, a Westminster boy and, later, a student
at Christ Church, was at once instructor and assistant to
Boyle. The year that the Royal Society received their
charter, they appointed Hooke curator, and his duty was
" to furnish the Society " every day they met with three or
four considerable experiments. This formidable task he
fulfilled in spite of the fact that " the fabrication of instru-
ments for experiments was not commonly known to work-
men," and that he never received " above £50 a year and

K 2

260 Britain's Heritage of Science

that not certain." Hookewas a man of amazing versatility,
very self-confident, attacking problems in all branches of
science, greatly aiding their advance, but avid of fame.

" In person but despicable, being crooked and low in

stature, and as he grew older more and more deformed.

He was always very pale and lean and latterly nothing

but skin and bone."

His book " Micrographia " is the record of what a modern
schoolboy newly introduced to the microscope would write
down. Yet he was undoubtedly, although not a lovable
character, the best " mechanic of his age."1 (See also p. 55.)

John Tradescant ( ? ?1637) is by some believed to have

been a Dutchman, but his name is an English name, and he
seems from an early age to have owned land in Essex, a most
English county. One of his earliest works was entitled :
" A voiag of ambasad ondertaken by the Right honourabl
Sr Dudlie Digges in the year 1618," which is a narrative of
a voyage round the North Cape to Archangel, where they
arrived at the neighbouring monastery of St. Nicholas on
the 16th July 1618, when Tradescant immediately began
botanizing, collecting, and ultimately sending a number of
northern plants to various friends abroad and making notes
upon some twenty -four wild species. This was the first
account published of the plants of Russia. In 1620 he
voyaged south instead of north, having joined the expedi-
tion of Mansell and Sir Samuel Argall against the Corsairs
of Algiers, and amongst other rarities brought back by him
was the Algerian apricot. In 1625 he was in the service of
the Duke of Buckingham, and writes to an agent in Virginia
that it was the Duke's wish that he should " deal with all
merchants from all places, but especially from Virginia,
Bermudas, Newfoundland, Guinea, Binney, the Amazon,
and the East Indies, for all manner of rare beasts, fowls,
and birds, shells, furs, and stones." On the death of the
Duke, Tradescant became gardener to the King and Queen,
and it is suggested that it was about this time that he
established his physic garden and museum at South Lam-
beth. The physic garden was one of the first established
in our kingdom, and Pulteney recalls that Tradescant

1 Waller's " Life of Hooke," 1705.

The Tradescants 261

was the first who brought together any considerable collec-
tion of subjects of natural history. His name is immor-
talised in the genus Tradescantia, a spider- wort which he
had introduced from Virginia. Parkinson, in his " Paradisus
terrestris," speaks of the elder Tradescant as " a painful
industrial searcher and lover of all nature's varieties," and
having " wonderfully laboured to obtain all the rarest fruits
he can hear of in any place of Christendom, Turkey, yea,
or the whole world."

His only child, John Tradescant (1608-1662), was born
at Meopham, Kent, and apparently succeeded his father as
gardener to Queen Henrietta Maria. In 1637, the younger
Tradescant was in Virginia gathering all varieties of ferns,
plants, and shells for the museum at Lambeth, and in 1656
he published his " Museum Tradescantianum : or collection
of rareties preserved in South Lambeth, near London." In
this task he was assisted by his friend Ashmole, and the
book, which runs into 179 pages, contains lists of birds,
mammals, fish, shells, insects, minerals, war instruments,
utensils, coins, and medals. It is interesting to note that
he had a complete " dodar " from the island of Mauritius.
This was the celebrated stuffed dodo of which the head and
foot are still preserved at Oxford. The complete body had
been studied by Willughby and Ray. On the 12th December
1659, Ashmole notes in his diary that " Mr. Tradescant and
his wife told me they had been long considering upon whom
to bestow their Closet of Curiosities when they died, and at
last had resolved to give it unto me." Ashmole had built
himself a large brick house near Lambeth adjoining that
which had been Tradescant's, and shortly after its comple-
tion removed the collection to his new house, and in 1677
he announced his intention of giving his collection to the
University of Oxford, on condition that a suitable building
be built to receive it. This was erected from the design of
Sir Christopher Wren, and the collections were transferred
to Oxford in 1683, when the name of Tradescant was rather
unjustly sunk in that of Ashmole.

There was a lull in Zoological Science during the
eighteenth century in our islands, and only the names of
one or two outstanding zoologists appear. That of Thomas

262 Britain's Heritage of Science

Pennant (1726-1798) must not, however, be forgotten. In
his boyhood he received a copy of Francis Willughby's
" Ornithology," and to that he attributed his interest in
natural history. He was for a time an undergraduate at
Queen's College, Oxford, but did not proceed to a degree.
Shortly after leaving Oxford he travelled through Cornwall
and studied the minerals and fossils of the county, and in
1754 he travelled in Ireland, but here he kept a very imper-
fect diary, " such," he adds, " was the conviviality of the
country." In 1765 we find him visiting France and staying
with Buffon. He also visited Voltaire at Ferney. whom he
found " very entertaining and a master of English oaths " ;
on his return journey at the Hague he met the celebrated
Pallas. The first part of his " British Zoology " appeared
in 1766, and his " Synopsis of Quadrupeds " five years later.

At various times in his life, Pennant thoroughly
explored much of the British Islands, and made copious
notes on the fauna, especially on the birds of the coast. In
1781 he published " A History of Quadrupeds," which was
a new and enlarged edition of his " Synopsis," and three
years later his " Arctic Zoology " appeared. Arctic explora-
tion has always fascinated our British naturalists.

Pennant certainly occupies a leading position amongst
the zoologists of the eighteenth century, and although he
did not reach such a high standard as Buffon, he was a
really learned man, and he had an undoubted faculty for
making dry and obscure things readable and plain.

Although, as we have said above, British zoology suffered
under a lull during the eighteenth century, the two Hunters,
William and John, helped with Pennant to keep the sacred
flame alight.

William Hunter (1718-1783) was born in Lanarkshire
and educated at Glasgow University. He first came to
London as dissector to Dr. James Douglas, whose son he
tutored, and with him he travelled on the Continent.
Later, he was remarkably successful as a lecturer, being
eloquent, competent, and capable of illustrating his dis-
courses with practical dissections. His success as an
obstetric surgeon was great, and he was appointed Physician
Extraordinary to Queen Charlotte in 1764.

Thomas Pennant, The Hunters 263

During his comparatively long life he had accumulated
a notable collection of anatomical and pathological speci-
mens, and in 1765 he proposed to build a museum to house
them, and to spend several thousands of pounds on the
building, in addition to which he was prepared to endow
a professorship. The offer which he had made to the
Government, however, fell through, and subsequently he
undertook, at his own expense, to carry out the project
without Government aid, and he built his well-known
institution in Great Windmill Street. By 1783 he reckoned
that his collections had cost him over £20,000.

Unfortunately he and his brother John quarrelled, or
at least differed, the cause being that William claimed the
credit of more than one discovery which John seems to
have made. His collections, which by the time of his death
included minerals, shells, corals, coins, rare manuscripts
and books, together with his great obstetrical collection,
were ultimately left to the University of Glasgow. William
Hunter's claim to a place in these pages is that he was both
a great collector, a great investigator, and a great teacher.

His younger brother, John Hunter (1728-1793), came to
London in 1748 to assist William, and soon showed a real
genius for anatomy. He became a " Master of Anatomy "
of the Surgeons' Corporation and a pupil at St. George's
Hospital, where for a time he was house surgeon. Also he
resided for some terms at Oxford, where, he says, " they
wanted to make an old woman of me, or that I should stuff
Latin and Greek at the University, but," he added signifi-
cantly, pressing his thumb on the table, " these schemes I
cracked like so many vermin as they came before me."

John was more of an investigator than William, but a
far less able teacher. He traced the descent of the testis
in the foetus, as Aristotle is said to have done before him,
he investigated the placental nerves, studied the nature of
pus, investigated the absorbing power of veins, and in con-
junction with his brother endeavoured to determine the
course and function of the lymphatics.

After abandoning his partnership with William he served
abroad with the British Army in Portugal and elsewhere,
and became a great authority on gun-shot wounds. On

264 Britain's Heritage of Science

returning to London in 1763, he began to practise as a
surgeon in Golden Square, and here he first started on his
famous collections. The menagerie at the Tower and other
private zoological gardens served him with material, and he
spared neither time nor money to add to his museum. In
1764 he built himself a house at Earl's Court, Kensington,
which was properly fitted for macerating, injecting, and
dissecting the bodies of animals, and was also provided
with cages for keeping them alive. His sympathy was in
no way confined to the vertebrates, for he had ponds in
which he tried artificially to produce pearls in oysters, and
he was very fond of bees, though in truth his real passion
was for the fiercer kind of carnivora.

John Hunter helped a number of men who have left
their mark in the medical profession. Perhaps the most dis-
tinguished of these was Edward Jenner, but Astley Cooper,
John Abernethy, Henry Cline, James McCartney were also
of the company. In 1783 he built a large museum, with
lecture-rooms, in Leicester Square, and about this time he
made his well-known discovery on the collateral circulation
by anastomosing branches of blood-vessels.

In character he seems to have been impatient and rather
rough, incapable of readily expounding the information that
he had acquired — information that was mostly from direct
observation, for he read but little. He was a strong Tory,
and it is stated that he would rather have seen his museum
burning than show it to a democrat. Hunter stood at the
head of British surgery, but he was more than a surgeon,
he was an all-round anatomist, with wide and scientific
views as to what life meant. His claim to appear in these
pages is that he was also a great comparative anatomist,
though his zoology was always secondary to his surgery.
By his will his museum was offered to the British Govern-
ment on reasonable terms, and in case they refused it was
to be sold to some foreign State or put up to auction.
National finance in 1793 was, however, at a low ebb, and
Mr. Pitt showed no eagerness to complete the purchase.
Six years later the Government recommended the collection
should be bought for £15,000, knowing well that it was
worth a great deal more. However, the purchase was

John Hunter, Richard Owen 265

completed and the collection was offered to the Royal
College of Physicians. On their refusal to accept it, it was
offered to and accepted by the Corporation of Surgeons,
which next year became the Royal College of Surgeons,
and from 1806 the Hunterian Collection has been housed
in Lincoln's Inn Fields. At the present time this original
nucleus of the College museum comprises one-fifth of the
specimens therein exhibited.

The most dominant zoologist in the first half of the
nineteenth century was Sir Richard Owen (1804-1892), who
was born at Lancaster and was educated at the grammar
school of that town with William Whewell, the author of
the " History of the Inductive Sciences." When he was
sixteen he was apprenticed to a surgeon, and here his love
of anatomy at once found scope. Later he matriculated
at Edinburgh, and attended the extra-mural course of
lectures on anatomy given by Dr. John Barclay, who, as
Owen himself testified, has an " extensive knowledge of
vertebrate anatomy." In the spring of 1835 he joined
St. Bartholomew's Hospital, London, having passed the
examination of the Royal College of Surgeons, and later
set up in private practice near Lincoln's Inn Fields. He
became lecturer on Comparative Anatomy at his hospital in
1827, and after a short interval he was appointed Assistant
Conservator of the Hunterian Museum of the Royal College
of Surgeons. The Conservator was then William Clift, who
had done so much to preserve Hunter's Museum in the
long interval between his death and its transference to
the Royal College of Surgeons. In 1831 Cuvier invited
Owen to Paris, where he attended Cuvier's and Geoffroy
St. Hilaire's lectures in the Jardin des Plantes.

Owen was well known as a writer of monographs on
many rare animals, and the first of these was his memoir
on the " Pearly Nautilus," which placed him, as Huxley
says, " in the front rank of anatomical monographers."
In the early forties, he succeeded Clift, whose daughter
he had married, as Conservator to the Royal College of
Surgeons. But before this, in 1836, he had been made the
first Hunterian Professor of Comparative Anatomy at the
College, which involved the annual delivery of twenty-four

266 Britain's Heritage of Science

lectures, and these he continued to give for a period of
twenty years.

Owing to the influence of the Prince Consort, the
British Court was, in Owen's time, more interested in
science than it has been since his death, and Owen became
of considerable influence in court and in society circles.
In 1845 he was elected a member of that exclusive body
" The Club," founded by Dr. Johnson. In 1852 the Queen

five him the cottage called Sheen Lodge, in Richmond
ark, where he lived for forty years.

There seems little doubt that in the middle of the last
century Owen was recognized throughout the world as the
first anatomist of his day; but his position at the College
of Surgeons was at this time becoming difficult. Friction
arose between him and the Governing Body, and in 1856
he readily accepted the offer made to him by the Trustees
of the British Museum to undertake the newly created post
of Superintendent of the Natural History Department in
the Museum. This post he held until 1884. He added
greatly to our knowledge of animal structure by his success-
ful dissection of many rare forms, such as the Pearly
Nautilus, Limulus, Lingula, Apteryx, and others, and, follow-
ing on the lines of Cuvier, he was particularly successful in
reconstructing extinct vertebrates. Another considerable
advance he made in science was his introduction of the
terms " homologous " and " analogous."

The accommodation afforded by the Museum at Blooms-
bury for Natural History specimens was totally inadequate,
and as early as 1859 Owen submitted a report to the Trustees
setting forth his views as to the proper housing of the
National collections. After the usual delays attendant upon
all Government action, land was purchased at South
Kensington, on which ten years later the present buildings
rose. They were opened to the public in 1881. Owen failed,
however, to achieve many of his desires. A lecture theatre,
such as exists in the Metropolitan Museum of Natural
History in New York, is even now still lacking, and, he
adds, " no collection of zoological specimens can be regarded
as complete without a gallery of physical ethnology.'' This
also is still wanting. A third of his wishes, a gallery of

Richard Owen, Charles Darwin 267

Cetacean skeletons, was only achieved under his successor,
Sir William Flower. The fact was, as Sir William pointed
out, that the division of the Museum into four departments,
each with its own head, left Owen practically powerless.
Increased age added to the difficulties, and in 1883 he
resigned his post and spent the remaining nine years of his
life in retirement in his beautiful cottage at Sheen Lodge.

Owen was widely read, fond of music and the drama,
and a man of striking personality. But, owing to his
faculty for acrimonious controversy, he was rather an
isolated zoologist, standing alone and going his own way.
His power of work was prodigious : not only did he pub-
lish innumerable papers in all the scientific journals, but a
large number of books, the titles of which are set forth in
the " Dictionary of National Biography."

On the same day, the 12th February 1809, upon which
Abraham Lincoln first saw the light, was born, at the
" Mount," Shrewsbury, a little child destined as he grew
up to alter our conceptions of organic life perhaps more
profoundly than any other man has ever altered them,
and this not only in the subjects he made his own, but in
every department of human knowledge and thought.

As to the man, two estimates of his character may
be quoted, one by a student who lived on terms of close
intimacy with Darwin when at Christ's College, Cambridge,
the other the considered judgment of one who knew and
loved and fought for Darwin in later life.
Mr. Herbert says :

" It would be idle for me to speak of his vast
intellectual powers . . . but I cannot end this
cursory and rambling sketch without testifying, and I
doubt not all his surviving college friends would concur
with me, that he was the most genial, warm-hearted,
generous, and affectionate of friends ; that his sympathies
were with all that was good and true; and that he had
a cordial hatred for everything false, or vile, or cruel,
or mean, or dishonourable. He was not only great, but
pre-eminently good, and just, and lovable."
Professor Huxley, speaking of the name of Darwin, says :
" They think of him who bore it as a rare combination

268 Britain's Heritage of Science

of genius, industry, and unswerving veracity, who earned
his place among the most famous men of the age by sheer
native power, in the teeth of a gale of popular prejudice,
and uncheered by a sign of favour or appreciation from
the official fountains of honour; as one who, in spite of
an acute sensitiveness to praise and blame, and notwith-
standing provocations which might have excused any
outbreak, kept himself clear of all envy, hatred, malice,
nor dealt otherwise than fairly and justly with the
unfairness and injustice which was showered upon him;
while, to the end of his days, he was ready to listen
with patience and respect to the most insignificant of
reasonable objectors."

Although the Darwin family trace their ancestry to about
the year 1500, we need not, here, go further back than
Charles's grandfather, Erasmus (1731-1802). This distin-
guished physician, the author of the " Loves of the Plants "
and of " Zoonomia," transmitted to his grandson his bene-
volent and sympathetic character and a remarkable charm
of manner, as well as his great stature.

In many respects Erasmus Darwin was in advance of
his times. He was, for instance, a great advocate of temper-
ance, and Mr. Lucas has lately reminded us of his inhuman
advice : " If you must drink wine, let it be home-made,"
surely the shortest cut to total abstinence yet devised by
the wit of man.

He wrote innumerable verses in the somewhat stilted
style of the period. They were immensely admired by his
contemporaries, and Cowper, who could have had little or
no sympathy with most of Darwin's views, wrote in
conjunction with Halley a poem in his honour which
begins : —

" No envy mingles with our praise,

Tho' could our hearts repine
At any poet's happier lays,

They would, they must, be thine."

The third son of Erasmus, Robert Waring Darwin, was
the father of Charles. Like his father, he was a physician,
and for many years he enjoyed a large practice at Shrewsbury.
He married Susannah, the daughter of his father's friend,

Charles Darwin

From a photograph by

Erasmus Darwin, Charles Darwin 269

Josiah Wedgwood, of the well-known pottery works at
Etruria, Staffordshire.

In his charming and frank fragments of autobiography
Darwin recalls many incidents of his own childhood. As
a boy he early developed a taste for collecting plants, shells,
minerals and other natural objects, and he was at pains to
learn their names. He tells a curious story of himself
pretending that he could alter the colour of flowers by
watering them with coloured fluids, curious because at his
age boys are not as a rule interested in such problems
of vegetable physiology. It is characteristic that in the
earliest portrait of him, a charming crayon sketch in which
his youngest sister Catherine also appears, he is depicted
holding a pot of flowers in his hands. At the age of nine
he was sent to the school at Shrewsbury, then in its picturesque
old buildings in the town ; he was a boarder there, and thus
had, as he says, "the great advantage of living the life of a
true schoolboy." He remained at school until he was sixteen,
and then his father, thinking he was not doing much good,
sent him to join his elder brother, who was studying medicine
at Edinburgh University. At this period, like his grand-
father, his father and his brother, Darwin was destined to
study medicine, and he attended the medical course, which
consisted entirely of lectures, all of them, with but one
exception, " intolerably dull." Apart from the lectures,
which were evidently almost useless, Darwin acquired a
good deal of miscellaneous information whilst at Edinburgh ;
he did much collecting along the shore, learnt the art of the
bird-stuffer, frequented two or three societies, and doubt-
less, as is the habit of those of his age, took part in many
and interminable discussions. He also became an ardent
sportsman and was especially enthusiastic about shooting.
Apparently, however, his heart was not in his medical
work, and in 1827 his father proposed that he should become
a clergyman, and with this in view decided to send him to
Cambridge.

The Admission Book at Christ's College contains the
following entry : —

" Admissi sunt in Collegium Christi a Festo Divi

Michaelis 1827 ad Fes um eiusdem 1828 :

270 Britain's Heritage of Science

[No. 3.]

Octobris 15. Carolus Darwin admissus est pensionarius

minor sub Mro Shaw."

Charles Darwin came into residence in the Lent Term
of 1828.

Late in life men are apt to look back upon their College
days with a somewhat exaggerated regret for lost oppor-
tunities, and Charles Darwin felt that at Cambridge his
" time was wasted, as far as his academical studies were
concerned, as completely as at Edinburgh and at school."
But this must not be taken too literally. He seems to have
passed his University examinations with ease, and a letter
recording his joy at getting through the " Little-Go " shows
that he at any rate took them seriously.

Apparently Darwin's experiences at Edinburgh had given
him a distaste for lectures, and it is unfortunate that this
distaste kept him away from the teaching of Sedgwick. He
attended, however, the botanical lectures of Henslow, which
were then crowded with students as well as with senior
members of the University, and he revelled in the excursions
which Henslow used to conduct, on foot or in coaches, or
down the river in barges, "or to some more distant place,
as to Gamlingay, to see the wild lily of the valley and to
catch on the heath the rare natterjack." He was, in fact,
known to the senior members of the University as " the
man who walks with Henslow," and the man who walked
with Henslow did not spend three years at Cambridge wholly
in vain.

Amongst other absorbing pursuits was that of collecting
insects, especially beetles. He was first interested in ento-
mology by his cousin, W. Darwin Fox, of Christ's, who
had kindred tastes and with whom he frequently corre-
sponded— in fact, most of the letters written from Christ's
College that remain were addressed to him.

Darwin received his degree on April 26, 1831, and it was
during this term and the subsequent Easter term, when he
was still in residence, that Henslow persuaded him to begin
the study of geology. There must have been something
unusual about Darwin, for he seems to have made friends
with men much older than himself, and some of them, one

Charles Darwin 271

would imagine, not very approachable. He records how
he used to walk home at night with Dr. Whewell; and
rejoices in his friendship with Leonard Jenyns. He became
the friend of Adam Sedgwick, and in August 1831 he
accompanied him on a geological survey in North Wales.
It was on returning from this trip that he found a letter
from Henslow informing him that Captain Fitzroy was
willing to give up part of his cabin to any young man who
would volunteer without pay to act as naturalist on the
classical voyage of the Beagle. Captain Fitzroy was going
out to survey the southern coast of Tierra del Fuego and
to visit some of the South Sea Islands, returning by the
Indian Archipelago.

Captain Fitzroy, like Mrs. R. Wilfer, was a " disciple
of Lavater," and took exception to the shape of Darwin's
nose. " He doubted whether any one with my nose could
possess sufficient energy and determination for the voyage."
But on acquaintance his doubts soon vanished, and the
captain and his naturalist became close friends.

Space forbids any account of the voyage of the Beagle.
As far as Darwin is concerned, it took place at what is,
perhaps, the period of life when the mind is most original.
Many of the great creative ideas of thought appear to be
engendered between the age of twenty and thirty years,
and although much may be added later, the foundation of
man's life work is usually laid then. Darwin, as he records,
" worked to the utmost during the voyage from the mere
pleasure of investigation and from " his " strong desire to
add a few facts to the great mass of facts in Natural Science."

He returned to England in October 1836, and two months
later, on December 13, Darwin settled again in Cambridge,
but only for three months.

Whatever feeling Darwin had about the education that
he received at Cambridge, he had a real love for the place,
to which he sent all but one of his sons; and it is good to
read the following lines in his autobiography : " Upon the
whole, the three years I spent at Cambridge were the most
joyful of my happy life."

Early in the year 1839 Darwin married his cousin, Emma
Wedgwood, and for nearly four years they kept house in

272 Britain's Heritage of Science

Upper Gower Street. The sustained toil and the discomforts
of the voyage had injured Darwin's health, and he and his
wife led a life of " extreme quietness." During this period,
he states, " I did less scientific work, though I worked as
hard as I possibly could, than during any other equal length
of time in my life. This was owing to frequently recurring
unwellness and to one long and serious illness." His health,
indeed, prevented his regular attendance at scientific and
other gatherings which are among the few attractions London
can offer over the country, and in 1842 he removed to the
secluded Kentish village of Down. The chief attraction of
the place was its quietness, " its chief merit," as Darwin
writes, " is its extreme rurality." The house stands a
quarter of a mile from the village, whose peaceful charm
has been but little altered in the last sixty-seven years.
And here it was he says : "I can remember the very spot,
whilst in my carriage, when to my joy the solution occurred
to me." The " solution " was " natural selection by means
of the survival of the fittest."

Here for forty years Darwin lived and laboured, in spite
of ill-health which often laid him aside for weeks, his daily
task always confined to very few hours of work. We need
not follow further the details of this happy life, but one
event, and that a well-known one, may briefly be referred
to. Darwin's work was so catholic, its bulk so great and
its effect so stimulating, that few have realised how vast
was the output of scientific work which, though often an
invalid, he gave to the world. The extent of the work has
been perhaps a little overshadowed by the immense import-
ance of that great generalization known as Natural Selection.
Sir Wm. Thiselton-Dyer has reminded us that Darwin lies
beside Newton in Westminster Abbey, and he adds : "It
is the singular fortune of an illustrious University that of
two of her sons, one should have introduced a rational order
into the organic and the other into the inorganic world."

In 1908 was celebrated the Jubilee of the reading of a
Paper at the Linnean Society entitled, " On the Tendency
of Species to form Varieties; and on the Perpetuation of
Varieties and Species by Natural Means of Selection." This
was the joint production of Charles Darwin and of Alfred

Charles Darwin, Alfred Wallace 273

Russell Wallace, and was laid before the Society by Sir
Joseph Hooker and Sir Charles Lyell. The history of this
Paper is well known, but it is so creditable to both these
high-minded and honourable men that I may briefly repeat
it, and in doing so I cannot do better than use the noble
words1 of Wallace : —

" The one fact," said Wallace, " that connects me
with Darwin, and which, I am happy to say, has never
been doubted, is that the idea of what is now termed
* natural selection ' or * survival of the fittest,' together
with its far-reaching consequences, occurred to us
independently, and was first jointly announced before this
Society fifty years ago.

" But what is often forgotten by the press and the
public is, that the idea occurred to Darwin in October
1838, nearly twenty years earlier than to myself (in
February 1855); and that during the whole of that
twenty years he had been laboriously collecting evidence
from the vast mass of literature of Biology, of Horti-
culture, and of Agriculture; as well as himself carrying
out ingenious experiments and original observations,
the extent of which is indicated by the range of subjects
discussed in his * Origin of Species,' and especially in that
wonderful store-house of knowledge — his ' Animals and
Plants under Domestication,' almost the whole materials
for which works had been collected, and to a large extent
systematized, during that twenty years.

" So far back as 1844, at a time when I had hardly
thought of any serious study of nature, Darwin had
written an outline of his views, which he communicated
to his friends, Sir Charles Lyell and Dr. (now Sir Joseph)
Hooker. The former strongly urged him to publish an
abstract of his theory as soon as possible, lest some other
person might precede him — but he always refused till
he had got together the whole of the materials for his
intended great work. Then, at last, Lyell 's prediction
was fulfilled, and, without any apparent warning, my
letter, with the enclosed Essay, came upon him, like a

1 The Darwin-Wallace Celebration. The Linnean Society, London,
1908, pp. 5-7.

S

274 Britain's Heritage of Science

thunderbolt from a cloudless sky ! This forced him to what
he considered a premature publicity, and his two friends
undertook to have our two papers read before this Society.
" How different from this long study and preparation
— this philosophic caution — this determination not to
make known his fruitful conception till he could back
it up by overwhe-lming proofs — was my own conduct.
The idea came to me, as it had come to Darwin, in a
sudden flash of insight : it was thought out in a few
hours — was written down with such a sketch of its various
applications and developments as occurred to me at the
moment, — then copied on thin letter-paper and sent off
to Darwin — all within a week. / was then (as often
since) the ' young man in a hurry ' : he, the painstaking
and patient student, seeking ever the full demonstration
of the truth that he had discovered, rather than to achieve
immediate personal fame."

It is a remarkable fact that both naturalists owed their
inspiration to the same source. Both had read the " Essay
on Population," written by a modest clergyman named
Malthus, a book which on its appearance was met with a
storm of execration; both saw in it the demonstration of
that lt struggle for existence " which surrounds us on all
sides, and both and they alone of all the readers of Malthus)
saw that the necessary consequence of this struggle for
existence was that the fittest alone, survive. This concep-
tion, " an essentially new creative thought," as Helmholtz
described it, explained the method of that evolution which
since the tima of the Greeks has been at the back of man's
mind. It thus rendered the fact of evolution acceptable
and even inevitable in the minds of all intelligent thinkers
and brought about changes in our attitude to the organic
world and indeed in our whole relation to life greater, perhaps,
than have ever been produced by any previous thought of
man.

There were, of course, many British evolutionists before
Darwin, amongst whom may be mentioned Charles Darwin's
grandfather, Erasmus Darwin, Wells, Patrick Matthew,
Pritchard, Grant, Herbert — all these writers advocated, and
some even hinted at, natural selection. Above all, Bobert

Natural Selection 275

Chambers, whose " Vestiges of Creation " remained anonymous
until after his death, strongly pressed the view that new
species of animals were being evolved from simpler types.

During the incubatory period of Darwin's great work, as
Alfred Newton has remarked, systematists, both in zoology
and botany, had been feeling great searchings of heart as
to the immutability of species. There was a general feeling
in the air that some light on this subject would shortly appear.
As a recent writer has reminded us,

" in studying the history of evolutionary ideas, we
must keep in mind two distinct lines of thought, first,
the conviction that species are not immutable, and that
by some means or other new forms of life are derived
from pre-existing ones. Secondly, the conception of some
process or processes by which this change of old forms and
new ones may be explained."

Now, as we have seen, the first of these lines of thought
had been accepted by many writers. Darwin's great merit
was that he conceived a process by means of which this
evolution in the organic kingdom could be explained.

It has been somewhat shallowly said, said in fact on the
day of the centenary of Darwin's birth, that " we are upon
very unsafe ground when we speculate upon the manner in
which organic evolution has proceeded without knowing
in the least what was the variable organic basis from which
the whole process started." Such statements show a certain
misconception, not confined to the layman, as to the scope
and limitations of scientific theories in general, and to the
theory of organic evolution in particular. The idea that
it is fruitless to speculate about the evolution of species
without determining the origin of life is based on an erroneous
conception of the true nature of scientific thought and of the
methods of scientific procedure. For Science, the world of
natural phenomena is a complex of procedure going on in
time, and the sole function of Natural Science is to construct
systematic schemes forming conceptual descriptions of
actually observed processes. Of ultimate origins Natural
Science has no knowledge and can give no account. The
question whether living matter is continuous or not with
what we call non-living matter is certainly one to which an

S 2

276 Britain's Heritage of Science

attempted answer falls within the scope of scientific method.
If, however, the final answer should be in the affirmative
we should then know that all matter is living, but we should
be no nearer to the attainment of a notion of the origin of
life. No body of scientific doctrine succeeds in describing in
terms of laws of succession more than some limited set of
stages of a natural process ; the whole process — if, indeed, it
can be regarded as a whole — must for ever be beyond the
reach of scientific grasp. The earliest stage to which Science
has succeeded in tracing back any part of a sequence of
phenomena itself constitutes a new problem for Science and
that without end. There is always an earlier stage and to an
earliest we can never attain. The questions of origins
concern the theologian, the metaphysician, perhaps the poet.
The fact that Darwin did not concern himself with questions
as to the origin of life nor with the apparent discontinuity
between living and non-living matter in no way diminishes
the value of his work. The broad philosophic mind of the
great Master of inductive method saw too fully the nature of
the task he had set before him to hamper himself with
irrelevant views as to origins.

No well-instructed person imagines that Darwin spoke
either the first or the last word about organic evolution.
His ideas as to the precise mode of evolution may be, and
are being, modified as time goes on. This is the fate of all
scientific theories; none, are stationary, none are final.
The development of Science is a continuous process of evolu-
tion, like the world of phenomena itself. It has, however,
some few landmarks which stand out exceptional and
prominent. None of these is greater or will be more enduring
in the history of thought than the theory associated with
the name of Charles Darwin.

But in reading his writings and his son's admirable " Life "
one attains a very vivid impression ,of the man. One of
his dominant characteristics was simplicity — simplicity and
directness. In his style he was terse, but he managed to
write so that even the most abstruse problems became clear
to the public. The fascination of the story he had to tell
was enhanced by the direct way in which he told it.

One more characteristic. Darwin's views excited at the

Organic Evolution 277

time intense opposition and in many quarters intense hatred.
They were criticised from every point of view, and seldom
has a writer been more violently attacked and abused. Now
what seems so wonderful in Darwin was that — at any rate
as far as we can know — he took both criticism and abuse
with mild serenity. What he wanted to do was to find the
truth, and he carefully considered any criticism, and if it
helped him to his goal he thanked the critic and used his
new facts. He never wasted time in replying to those who
fulminated against him, he passed them by and went on
with his search.

It is a somewhat remarkable fact that whilst the works
of Darwin stimulated an immense amount of research in
Biology, this research did not at first take the line he
himself had traced. With some exceptions, the leading
zoological work of the end of the last century took the form
of embryology, morphology, and palaeontology; and such
subjects as cell-lineage, the minute structure of protoplasm,
life-histories, teratology, have occupied the minds of those
who interest themselves in the problems of life. Among
all these lines of research man has been seeking for the
solution of that secret of nature which at the bottom of his
heart he knows he will never find, and yet the pursuit of
which is his one abiding interest. Had Francis Balfour
lived we should, probably, have sooner returned to the broader
lines of research as practised by Darwin, for it was Balfour's
intention to turn himself to the physiology — using the term
in its widest sense — of the lower animals. Towards the
end of the nineteenth century, stimulated by Galton, Weldon
began those series of measurements and observations which
have culminated in the establishment of a great school of
Eugenics and Statistics in London. With the beginning of
the twentieth century came the rediscovery of the neglected
facts recorded by Gregor Mendel, Abbot of Brunn, some
years before, and with that rediscovery an immediate and
enormous outburst of enthusiasm and of work. Mendel
had placed a new instrument in the hand of the breeder,
an instrument which, when he has learnt to use it, may give
him a power over all domesticated animals and cultivated
crops undreamt of before. We are getting a new insight

278 Britain's Heritage of Science

into the workings of Heredity and we are acquiring a new
conception of the individual. The few years which have
elapsed since men's attention was redirected to the principles
first enunciated by the Abbot of Brunn have seen a School
of Genetics arise at Cambridge, and an immense amount of
practical experiment on inheritance has also been done in
France, Holland, Austria, and especially in the United States.
As the work has advanced new ideas have arisen and earlier
formed ideas have had to be abandoned; this must be so
with every advancing science. But it has now become
clear — at any rate to some competent authorities — that
mutations occur, and occur especially in cultivated species;
and that these mutations may breed true seems now to
be established. In wild species also they apparently occur,
but whether they are as common in wild as in cultivated
species remains to be seen. If they are not, in my opinion,
a most profitable line of research would be to endeavour to
determine what factor exists in cultivation which stimulates
mutation.

To what extent Darwin's writings would have been
modified had Mendel's work come into his hands we can
never know. He carefully considered the question of
mutation, or as they called it then, saltation, and as time
went on, he attached less and less importance to these
variations as factors in the origin of species. Ray Lan-
kester has recently reminded us that Darwin's disciple and
expounder, Huxley, " clung to a little heresy of his own as
to the occurrence of evolution by saltatory variation," and
there must have been frequent and prolonged discussion on
the point. That " little heresy " has now become the ortho-
doxy of a number of eager and thoughtful workers who have
been at times rather aggressive in their attacks on the
supporters of the old creed.

The publication of " The Origin of Species " naturally
aroused immense opposition and heated controversy. But
Darwin, as we have said, was no controversialist. Huxley
wrote shortly after his death :

" None have fought better, and none have been more

fortunate, than Charles Darwin. He found a great truth

trodden underfoot, reviled by bigots, and ridiculed by all

G. Mendel, C. Lyell, T. Huxley 279

the world ; he lived long enough to see it, chiefly by his
own efforts, irrefragably established in science, insepar-
ably incorporated with the common thoughts of men,
and only hated and feared by those who would revile,
but dare not. What shall a man desire more than this ?"
Darwin, also, was fortunate in his supporters, though some
of the leading biologists of the time — conspicuous among
them was Owen — rejected the new doctrine. In Hooker,
on the botanical side, in Huxley, on the zoological side, and
in Lyell, on the geological side, he found three of the ablest
intellects of his country and of his century as champions.
None of these agreed on all points with their leader, but
they gave more than general adherence to his principles,
and a more than generous aid in promulgating his doctrine.
Lyall was an older man, and his " Principles of Geology "
had long been a classic. This book inspired students who
became leaders in the revolution of thought which was
taking place in the last half of the nineteenth century. One
of these writes :

" Were I to assert that if the * Principles of Geology '
had not been written, we should never have had * The
Origin of Species,' I should not be going too far : at all
events, I can safely assert, from several conversations
I had with Darwin, that he would have most unhesi-
tatingly agreed to that opinion." x

Sir Joseph Hooker, whose great experience as a traveller
and a systematic botanist, and one who had at his time
the widest knowledge of the distribution of plants, was of
invaluable assistance to Darwin on the botanical side of his
researches. Those who knew Hooker will remember him
as a man of ripe experience, sound judgment, and a very
evenly-balanced mind. But all these high and by no means
common qualities were combined with caution, and with a
critical faculty, which was quite invaluable to Darwin at
this juncture. Huxley was of a somewhat different tempera-
ment. He was rather proud of the fact that he was named
after the doubting apostle ; but, whatever Huxley doubted,
he never doubted himself. He had clear-cut ideas, which
he was capable of expressing in the most vigorous and

1 J. W. JuddT"

280 Britain's Heritage of Science

the most cultivated English. Both on platform and on paper
he was a keen controversialist. He contributed much to
our knowledge of morphology. But never could he have
been mistaken for a field-naturalist. In the latter part of
his life he was drawn away from pure science by the demands
of public duty, and he was, undoubtedly, a power in the
scientific world. For he was ever one of that small band
in England who united scientific accuracy and scientific
training with influence on the political and official life of
the country.

As has already been said, the immediate effect of the
publication of " The Origin of Species " and of the acceptance
of its theories by a considerable and ever-increasing number
of experts did not lead to the progress of research along the
precise lines Darwin himself had followed. The accurate
description of bodily structure and the anatomical com-
parison of the various organs was the subject of one school
of investigators : Rolleston's " Forms of Animal Life,"
re-edited by Hatchett Jackson, Huxley's " Vertebrate and
Invertebrate Zoologies," and Milnes Marshall's " Practical
Zoology " testify to this. Another school took up with
great enthusiasm the investigation of animal embryology,
the finest output of which was Balfour's " Text-book of
Embryology," published in 1880. Members of yet another
school devoted themselves to the minute structure of the
cell and to the various changes which the nucleus undergoes
during cell-division. Animal histology has, however, been
chiefly associated with physiology and, as this chapter is
already greatly overweighted, we have had to leave physio-
logy on one side. The subjects of degeneration, as shown,
by such forms as the sessile Tunicata, the parasitic Crustacea
and many internal parasitic worms, with the last of which
the name of Cobbold is associated, also received attention,
and increased interest was shown on the pathogenic influence
of internal parasites upon their hosts.

Towards the end of our period, a number of new schools
of biological thought arose. As Judd tells us :

" Mutationism, Mendelism, Weismannism, Neo-La-

marckism, Biometrics — with which the name of W. F. R.

Weldon will ever be associated — * Eugenics ' began to

Alfred Russell Wallace 281

be exploited. But all of these vigorous growths have
their real roots in Darwinism. If we study Darwin's
correspondence, and the successive essays in which he
embodied his views at different periods, we shall find
that variation by mutation (or per saltum), the influence
of environment, the question of the inheritance of ac-
quired characters, and similar problems, were constantly
present to Darwin's ever open mind, his views upon them
changing from time to time, as fresh facts were gathered."
Like everything else, these new theories were deeply
rooted in the past.

We have already alluded to Alfred Russell Wallace
(1823-1913) and to the magnanimity with which he and
Darwin treated each other in the matter of their simul-
taneous discovery of the causes which had brought about
" The Origin of Species." Wallace was one of the last
of the great travelling naturalists and collectors. He
explored the Amazon with his friend Bates in the years
1848-1852. Two years later he visited and lived for some
years in the Indo-Malay Islands, and in both parts of the
globe he accumulated a vast series of facts from which
some of his widest generalisations sprang.

Wallace had a fine gift for writing, and his " Malay
Archipelago " is one of the most fascinating books in a
naturalist's library. Perhaps his most celebrated books are
his " Geographical Distribution of Animals " and " Island
Life," published in 1876, for, as Professor H. F. Osborn
reminds us, " Wallace takes rank as the founder of the
science of zoo-geography." " Wallace's Line " between
Bali and Lombok, the frontier between the Indian and
Australian regions, will ever recall his fame in this branch
of science.

He was a man of strong humanitarian instincts and
devoted a considerable amount of time in trying to devise
plans to help mankind and the state, and although many of
his views did not commend themselves to the majority his
sincerity was always fully recognized.

We must now return to many zoologists of about
Darwin's period who more than held their own as compared
with some continental claimants of scientific superiority.

282 Britain*s Heritage of Science

Although George James Allman (1812-1898) was Pro-
fessor of Botany at Dublin, he achieved his most marked
success as a zoologist. He left Dublin in 1856 on his
appointment to the Regius Professorship of Natural History
in the University of Edinburgh. He was, like so many men
of science, a good artist, and had exceptional skill in drawing
on the blackboard, and was a very popular lecturer, and he
took especial pleasure in taking his pupils on dredging
expeditions in the Firth of Forth and inducing them to
study marine organisms in the living state. His great work
on the Gymnoblastic Hydrozoa, published by the Ray
Society, is stated by his biographer to have been without
doubt the most important systematic work dealing with the
group of Ccelenterata that has ever been produced. " The
excellence of the illustrations alone would almost justify
us in placing this work in the first rank of zoological treatises."
But he was equally an authority on certain groups of Polyzoa,
and it should be recalled that he it was who invented the
terms " ectoderm " and " endoderm," besides a great many
other useful expressions, such as " ccenosarc," " tropho-
some " and " gonosome," and many others. But above all
he did much to clear up the difficulty of defining species in
the Ccelenterata.

Thomas Henry Huxley (1825-1895), a few years younger
than Wallace, was, as we have seen, another of Darwin's
supporters. He started life as a surgeon and, like Darwin,
owed much of his early reputation to a sea voyage. He
made a four years' cruise in H.M.S. Rattlesnake, 1846-
1850, during which he especially devoted himself to the
study of marine organisms. He was the first to dissociate
the hydrozoa from the star fishes, and the parasitic worms
and the infusoria, which had formed portions of Cuvier's
old group Radiata. He did much to clear up the relations
of the Medusa to the Hydroid, and he dwelt especially on
the two -layered condition of their body wall, pointing out
its analogy with the gastrula. Shortly after his return to
England in 1850, he was elected a Fellow of the Royal
Society at the unusually early age of 26.

As a morphologist, Huxley made immense advances.
Apart from his work on Co3lenterates, he investigated the

Thomas Huxley, William Flower 283

structural life-history of the Ascidians, wrote on the
Mollusca, and undertook a series of investigations into
fossil vertebrate forms, researched on Aphis and on croco-
diles, cleared up the mystery of the vertebrate skull,
and, in fact, covered an extremely wide area of investi-
gation. But Huxley was not only a great morphologist,
he was a great teacher and a great organiser. His text
books on the comparative anatomy of the Vertebrate and
of the Invertebrata were the starting points of many a
zoologist's career. His " Elementary Biology," which he
wrote in collaboration with Newail Martin, marks an epoch.
He was also a great lecturer, and although not fond of public
speaking, he was remarkably able, concise, and even
eloquent. He spared no pains, and would write and re-
write an address until he had got it into what he considered
a satisfactory form. Further, as he himself wrote of
Priestley, he was " a man and a statesman before he was
a philosopher," and Huxley took a leading part in public
affairs, sat on a large number of Royal Commissions and
departmental committees. He was a member of the first
School Board of the City of London, and by his popular
lectures made a real attempt to interest the working men
and all others in the importance of science. He was, for a
time, the Biological Secretary of the Royal Society, and in
this post took a large part in organizing the Challenger
Expedition of 1872-1876. He was elected President of the
Royal Society, but four years later was compelled to resign
on account of ill-health. He was the recipient of innumerable
honorary degrees and memberships of foreign societies, and
in 1892 was honoured by being made a Privy Councillor.

Owen's successor, Sir William Flower (1831-1899), was
trained at the University of London as a medical man, and
after touring on the Continent, he joined the army, and
was assistant surgeon hi the 63rd Regiment during the
Crimean Campaign, the trials of which were so severe that
his health was affected, and he had to retire from the army
and return to London. For a time he practised, but in
1861, was appointed Conservator of the Museum of the
Royal College of Surgeons, and here he found his career.
This unique museum was greatly increased under Flower.

284 Britain's Heritage of Science

The President of the Royal Society said, when presenting
Sir William with a royal medal, " it is very largely due to his
incessant and well-directed labours that the Museum of
the Royal College of Surgeons at present contains the most
complete, the best ordered, and the most accessible collec-
tions of materials for the study of vertebrate structures
extant."

Flower succeeded Huxley in the Hunterian Professor-
ship at the Royal College of Surgeons, and his lectures met
with great success, in fact, he was soon becoming the fore-
most authority on mammals, and his work on " Mammals,
Living and Extinct," which he published in London in
conjunction with Lydekker, is still regarded as a classic.
Perhaps if he had a favourite group it was the Cetacea, and
when he succeeded Owen as Superintendent of the Natural
History Museum at Kensington, he took the greatest
pleasure in having a large room specially constructed to house
their gigantic skeletons. His well-known " Osteology of
Mammals," in which he was assisted by Dr. Hans Gadow,
was, even if a little dry, one of the most accurate and com-
plete of student's books. Another side of his work was
Anthropology. He published innumerable papers on the
various races of mankind, fully utilising the valuable material
he had at the Royal College of Surgeons. In 1879 he was
elected President of the Zoological Society, and held the
position until his death. His energy greatly increased the
value and use of the gardens. In 1898 failing health com-
pelled him to retire from the position. Sir William was
a handsome, well-set-up man, always courteous to strangers,
with a ready, fluent address.

One of the unexpected results of Darwin's investigations
was to induce a number of the younger school of zoologists
to take up the study of Embryology. The most brilliant
of these was Francis Maitland Balfour (1851-1882). He
was educated at Harrow and at Trinity College, Cambridge.
Even as a student — acting under the advice of Michael
Foster, at that time Praelector of Physiology in Trinity
College — he devoted himself to clearing up some points in
the development of the chick. After taking his degree in
1873, he worked on the embryonic history of the Elasmo-

W. Flower, F. M. Balfour, A. Sedgwick 285

branch fishes at the Zoological Station at Naples. This
research gained him a Fellowship at Trinity College.

He was appointed lecturer on Animal Morphology at
Cambridge, and soon became the founder of an extremely
vigorous and active school of zoologists. His best known
work is, of course, his " Treatise on Comparative Embryo-
logy," the first volume of which appeared in 1880, and the
second in the following year. It was a masterly review of an
enormous number of observations scattered over a world-
wide literature, and its production involved a wide and
careful reading of multitudinous papers. He had remark-
able critical faculty, and a wonderful gift of insight and
intuition, so that his book threw light on many a doubtful
point. When he was but 27, he was elected a Fellow of
the Royal Society, and, if he had chosen, he might have
succeeded Rolleston as Professor at Oxford. Edinburgh
also coveted him; but he remained faithful to his own
University, and, in the spring of 1882, a special Professorship
of Animal Morphology was instituted for him at Cambridge.

Balfour died by a tragic accident in the Alps in the
summer of 1882, and in him died a young man of great
performance, and even greater promise. He was a man of
singular charm, and, as Professor Michael Foster wrote,
" he was high-minded, generous, courteous, a brilliant
fascinating companion, a steadfast friend. He won, as few
others did, the hearts of all who were privileged to know
him."

We must necessarily deal but shortly with a few more
names : —

George John Romanes (1848-1894), whose researches on
the physiology of the nervous and locomotor system of
jelly-fishes and echinoderms, and whose speculations on the
principle of Selection will preserve his name.

Adam Sedgwick (1854-1913), a great nephew of the
geologist, by his researches on Peripatus did much to eluci-
date the mystery of the Coelom in Arthropods, and so show
a possible connexion between this group and lower animals.
His views on the cell theory are now coming to their own.
For a year or two he was Professor of Zoology at Cambridge,
and at the time of his death he was Professor at the Royal

286 Britain's Heritage of Science

College of Science and Technology, in London, and though
he was by no means a fluent lecturer, he was a stimulating
and inspiring teacher.

Walter Frank Raphael Weldon (1860-1906), another
Cambridge man, succeeded Moseley as Professor at Oxford.
He was a brilliant teacher, full of enthusiasm, and did much
sound morphological work. The last years of his life he
devoted to the subject of Biometrics, and he was the co-
founder with Karl Pearson of Biometrika.

The mention of Biometrics recalls the name of one who,
though not a zoologist in the strict sense of the word, deserves
a distinguished place in the history of our subject. Francis
Galton (1822-1911) began active life as a student of medicine,
but, on his father's death, inherited independent means and
abandoned the professional career. He spent some time on
an extensive journey in Africa, but his mind soon turned
to science. It was, probably, his experiences as a traveller
that directed his attention, at first, to meteorology, and he
did some useful work hi that subject. On the publication
of the " Origin of Species," Galton at once adopted the
views advocated by Charles Darwin, who was his cousin.
He then became interested in the laws of heredity, and during
a series of years endeavoured to introduce scientific measure-
ments into the study of a subject in which previously quali-
tative estimates were considered sufficient. Feeling the
want of proper statistics, he instituted, during the National
Health Exhibition in 1884, an anthropometric laboratory,
for the purpose of collecting satisfactory data. This was
the forerunner of the present biometric laboratory at
University College, London. Following up suggestions by
Sir William Herschel and Dr. Foulds, who had proposed the
use of " finger-prints " as a means of identifying persons.
Galton proved the method to be reliable, and devised a
workable scheme for classifying the prints so as to make
them serviceable for rapid identification. He was also the
originator of the word " Eugenics " for the study of the
methods of improving the human race by breeding from the
best, and restricting the offspring of the worst ; and he must
be considered to be the founder of that branch of science.
Endowed with exceptional originality and a sympathetic

W. F. A. Weldon, F. Galton, E. R. Lankester 287

mind that allowed him to co-operate effectively with other
men, he rendered many useful services to science. He was
knighted in 1909, two years before his death. By his will
he left a sum amounting to about £45,000 for the foundation
of a chair of Eugenics in the University of London, expressing
the wish that Karl Pearson should be the first occupant of
tKe chair.

One of the rules laid down for the writers of this book
is that living authors should only be mentioned when their
work is so much interwoven with that of others whose
activities have been noticed that a wrong impression would
be created by omitting all reference to them. Professor
Sir E. Ray Lankester has added so much to our conceptions
of the morphology of the animal kingdom, so much more
than any other living man, that a short account of his re-
searches must be given. Mention must be made of his
investigation into the embryonic cell gland of the Mollusca,
his researches in the distribution of haemoglobin in the
Invertebrata, the wonderful way in which he, in collabora-
tion with one of his pupils, cleared up the structure of the
Lamellibranch gill, his work on the anatomy of the Limpet,
and the even more important series of investigations which
led to the assignment of Limulus to its proper position
amongst the Arachnids. He was the first to observe an
intracellular parasite (in the red corpuscle of the frog), but
from the scales of fossil fishes to the details of the Okapi,
there are few subjects in Zoology that do not owe something
to the investigations carried on by Lankester from 1862
to 1905. His name will ever be associated with the very
important and fundamental conception of the coelom, and
his views on this subject are set forth at length in Part II
of his Treatise on Zoology. With this theory must be
associated his views on Phleboedesis, a name given to the
theory that the lacunar blood-holding spaces forming the
haemocoel of the Mollusca and the Crustacea have no
connexion with the coelom, although they encroach in
certain animals on the space occupied by the coelomic
cavity. The discussion of how his theory differs from that
given in " Die Coelom Theorie " of the Hertwigs is set out
in the above-mentioned treatise.

288 Britain's Heritage of Science

In addition to these fundamental conceptions which have
done so much to clear up the structure of widely differ-
ing animals, Lankester has introduced many new terms
which have proved of permanent value in the science of
zoology. Amongst these may be mentioned " nephridium,"
" blastoderm," " stomodeum," " proctodeum." Further,
he introduced the terms " homogeny " and " homoplasy,"
to distinguish between the two very different senses in which
" homology " had previously been used.

As a maritime nation, Great Britain has led the way in
exploring the plant life and animals of the sea, the chemical
and physical nature of the sea water, and the geological
structure of the subaqueous earth. As long ago as 1749
Captain Ellis found that a thermometer, lowered on separate
occasions to depths of 650 fathoms and 891 fathoms respec-
tively recorded, on reaching the surface, the same tempera-
ture, namely, 53°. His thermometer was lowered in a
bucket ingeniously devised so as to open as it descended
and close as it was drawn up. The mechanism of this instru-
ment was invented by the Rev. Stephen Hales, D.D., to
whom we have referred above. Dr. Hales was an ingenious
soul and the author of many inventions, amongst others,
he is said to have suggested the use of the inverted cup
placed in the centre of a fruit-pie in which the juice
accumulates as the pie cools. His device of the closed
bucket with two connected valves was the forerunner of
the numerous contrivances which have since been used for
bringing up sea- water from great depths. The colour of
the sea and its salinity had also received attention in early
days, notably at the hands of the distinguished chemist,
Robert Boyle.

The invention of the self-registering thermometer by
Cavendish in 1757, provided another instrument essential
to the investigation of the condition of things at great
depths, and it was used in Lord Mulgrave's expedition to
the Arctic Sea in 1773. On this voyage attempts at deep-
sea soundings were made, and a depth of 683 fathoms was
registered. During Sir James Ross's Antarctic Expedition
(1839-1843) the temperature of the water was constantly
observed to depths of 2,000 fathoms. His uncle, Sir John

Marine Zoology 289

Ross, had, twenty years previously, on his voyage to
Baffin's Bay, made some classical soundings. One, two
miles from the coast, reached a depth of 2,700 feet, and
brought up a collection of gravel and two living crustaceans ;
another, 3,900 feet in depth, yielded pebbles, clay, some
worms, Crustacea, and corallines. Two other dredgings,
one at 6,000 feet, the other at 6,300 feet, also brought up
living creatures; and thus, though the results were not at
first accepted, the existence of animal life at great depths
was demonstrated.

With Sir James Ross's expedition we may be said to
have reached modern times; his most distinguished com-
panion, Sir Joseph Hooker, died as recently as 1911. It is
impossible to do more than briefly refer to the numerous
expeditions which have taken part in deep-sea exploration
during our own times

Professor Edward Forbes, who " did more than any
of his contemporaries to advance marine zoology," joined
the surveying ship Beacon in 1840, and made more than one
hundred dredgings in the ^Egean Sea. Mr. H. Goodsir sailed
on the Erebus with Sir John Franklin's ill-fated Polar
Expedition; and such notes of his as were recovered bear
evidence of the value of the work he did. In 1868 the
Admiralty placed the surveying ship Lightning at the disposal
of Professor Wyville Thomson and Dr. W. B. Carpenter
for a six weeks' dredging cruise in the North Atlantic; and
in the following year the Porcupine, by permission of the
Admiralty, made three cruises under the guidance of
Dr. W. B. Carpenter and Mr. Gwynne Jeffreys.

We owe to Forbes (1815-1854) the delimitation of this
zone of depth usually distinguished in European and other
seas. These are the Littoral zone, the Laminarian zone,
the Coralline zone, and the region of the deep sea corals.
The last two zones are now generally known as the Conti-
nental Shelf and the Continental Slope, and to these must
be added the floor of the deep ocean, a region which in
Forbes* time was regarded as uninhabited. Forbes, after
a very varied career, ultimately became a Professor at
King's College, London, and Curator of the Museum of the
Geological Society. His work in connexion with palaeonto-

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290 Britain's Heritage of Science

logy will be described in the chapter on Geology. He is
undoubtedly the leading naturalist of the earlier half of the
nineteenth century, a man of wide interests and of great
popularity, one who lived a full life, one who promoted
science, and who rendered a real service to every branch of
Biology.

Another naturalist of the same period was Phillip Henry
Gosse (1810-1888). As a young man he lived in Newfound-
land, and here it was he began the serious study of Nature.
His first work was on the Entomology of Newfoundland.
Later, he travelled extensively in North America. On
returning to England in 1839 he wrote his " Canadian
Naturalist." A few years later he was in Jamaica, collecting
and describing the native fauna and sending many specimens
home. His " Birds of Jamaica," illustrated by a series of
magnificent plates, is well known. But, perhaps, Gosse 's
name will live longer as a researcher on Marine Inverte-
brates. He particularly occupied himself with the zoophytes
and made a great hit with his book " The Aquarium," which
did much to stimulate amateurs to observe the littoral
fauna. His most serious contribution to science, however,
was his study of the sea anemones, Actinologia britannica
(1855-1860); but it must not be forgotten that he colla-
borated with Dr. Hudson in the fascinating two volumes
which these joint authors published in 1866 on the Rotifera.

Towards the end of 1872 H.M.S. Challenger left England
to spend the following three years and a half in traversing
all the waters of the globe. This was the most completely
equipped expedition which has left any land for the investi-
gation of the sea, and its results were correspondingly rich.
They have been worked out by naturalists of all nations,
and form the most complete record of the fauna and flora,
and of the physical and chemical conditions of the deep,
which has yet been published. Since the return of the
Challenger there have been many expeditions from various
lands, but none so complete in its conception or its
execution, as the British Expedition of 1872-1876.

The results of the exploration of the sea by the Challenger
have never been equalled. In one respect, however, they
were disappointing. It had been hoped that, in the deeper

Marine Zoology 291

abysms of the sea, creatures whom we only know as geo-
logical, fossilized, bony specimens, might be found in the
flesh; but, with one or two exceptions — and these of no
great importance — these were not found. Neither did any
new type of organism appear. Nothing, in fact, was dredged
from the depths or found in the tow-net that did not fit
into the larger groups that already had been established
before the Challenger was thought of. On the other hand,
many new methods of research were developed during this
voyage, and with it will ever be associated the names of
Wyville Thompson, mentioned above, Moseley, John Murray
and others who, happily, are still with us.

A few words should be said as to the part played by
cable-laying in the investigation of the subaqueous crust of
the earth. This part, though undoubtedly important, is
sometimes exaggerated; and we have seen how large an
array of facts has been accumulated by expeditions made
mainly in the interest of pure science. The laying of the
Atlantic cable was preceded, in 1856, by a careful survey
of a submerged plateau, extending from the British Isles
to Newfoundland, by Lieutenant Berryman of the Arctic.
He brought back samples of the bottom from thirty-four
stations between Valentia and St. John's. In the following
year Captain Pullen, of H.M.S. Cyclops, surveyed a parallel
line slightly to the north. His specimens were examined by
Huxley, and from them he derived the Bathybius, a primeval
slime which was thought to occur widely spread over the
sea-bottom and to be the most primitive form of living
matter. The interest in this " Urschleim " became merely
academic, when John Y. Buchanan, of the Challenger, showed
that it is only a gelatinous form of sulphate of lime, thrown
down from the sea-water by the alcohol used in preserving
the organisms found in the deep-sea deposits. It was
characteristic of Huxley to acknowledge his mistake and
never to mention the subject again.

The important generalizations of Dr. Wallich, who was
on board H.M.S. Bulldog, which, in 1860, again traversed
the Atlantic to survey a route for the cable, largely helped
to elucidate the problems of the deep. Wallich noticed
that no algce lived below the 200 fathom line; he collected

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292 Britain's Heritage of Science

animals from great depths, and showed that they utilize
in many ways organisms which fall down from the surface
of the water; he noted that the conditions are such that,
whilst dead animals sink from the surface to the bottom,
they do not rise from the bottom to the surface; and he
brought evidence forward in support of the view that the
deep-sea fauna is directly derived from shallow-water forms.
In the same year in which Wallich traversed the Atlantic,
the telegraph cable between Sardinia and Bona, on the
African coast, snapped. Under the superintendence of
Fleeming Jenkin, some forty miles of the cable, part of it
from a depth of 1,200 fathoms, were recovered. Numerous
animals, sponges, corals, polyzoa, molluscs, and worms were
brought to the surface, adhering to the cable. These were
examined and reported upon by Professor Allman, and
subsequently by Professor A. Milne Edwards; and, as the
former reports, we " must therefore regard this observa-
tion of Mr. Fleeming Jenkin as having afforded the first
absolute proof of the existence of highly organized animals
living at a depth of upwards of 1,000 fathoms." The
investigation of the animals thus brought to the surface
revealed another fact of great interest, namely, that some
of the specimens were identical with forms hitherto known
only as fossils. It was thus demonstrated that species
hitherto regarded as extinct are still living at great depths
of the ocean.

Throughout the century repeated attempts had been
made to classify the members of the animal kingdom on
a natural basis, but, until their anatomy and, indeed, their
embryology had been sufficiently explored, these attempts
proved somewhat vain. As late as 1869 Huxley classified
sponges with Protozoa, Echinoderms with Scolecida and
Tunicates with Polyzoa and Brachiopoda. By the middle
of the century, much work had been done in sorting out
the animal kingdom on a natural basis, and Vaughan
Thompson had already shown that Flustra was not a hydroid,
but a member of a new group which he named Polyzoa.
He, although hardly remembered now, demonstrated that
Cirrepedia are not molluscs by tracing their development,
he established the fact that they began life as free-swimming

F. D. Godman, 0. Salvin 293

Crustacea ; he, again, it was who showed that Pentacrinus is
the larval form of the feather-star, Antedon.

The custom of naturalists to go on long voyages was
still maintained, and during the nineteenth century, many
other expeditions besides that of the Challenger, left Great
Britain to explore the natural history of the world, some
under public, some under private, auspices. They are too
numerous to mention. But a word must be said about the
wonderful exploration of Central America which has just
been completed, under the auspices of F. D. Godman and
0. Salvin. The results are incorporated in a series of magni-
ficently illustrated quarto volumes which have been issued
during the last thirty -six years. Fifty -two of these relate
to zoology, five to botany, and six to archaeology. Nearly
40,000 species of animals have been described in these
volumes, about 20,000 being new species, and nearly 12,000
species of plants. There are few remote and partially
civilized areas of the world whose zoology and botany are
on so secure a basis, and this is entirely owing to the muni-
ficence and enterprise of the above-mentioned gentlemen.

With regard to our own shores, one of the features of
the latter part of the nineteenth century has been the
establishment of marine biological stations, the largest of
which is that of the Marine Biological Association at Ply-
mouth. The Gatty laboratory at St. Andrews, the labora-
tories at Port Erin in the Isle of Man, and at Cullercoats,
have also, for many years, being doing admirable work.
All these establishments have devoted much technical skill
and time to solve fishery and other economic problems
connected with our seas.

294 Britain's Heritage of Science

CHAPTER XI

PHYSIOLOGY

HARVEY (1578-1657), who, like Newton, worked in one
of the two sciences which, in Stewart times, were, to
some extent, ahead of all the others, was undoubtedly the
second man of outstanding genius in science in the seventeenth
century. Harvey, " the little choleric man " as Aubrey
calls him, was educated at Caius College, Cambridge, and
at Padua, and was in his thirty-eighth year when, in his
lectures on anatomy, he expounded his new doctrine of
the circulation of the blood to the College of Physicians,
although his " Exercitatio " on this subject did not appear
till 1628. His notes for the lectures are now in the British
Museum. He was physician to Charles I., and it is on record
how, during the battle of Edgehill, he looked after the
young princes as he sat reading a book under a hedge a little
removed from the fight.

In the chain of evidence of his convincing demonstration
of the circulation of the blood one link, only to be supplied
by the invention of the compound microscope, was missing.
This, the discovery of the. capillaries, was due to Malpighi,
who was amongst the earliest anatomists to apply the com-
pound microscope to animal tissues. Still, as Dryden has it —

" The circling streams once thought but pools of blood —
(Whether life's fuel or the body's food),
From dark oblivion Harvey's name shall save." 1

Harvey was happy in two respects as regards his dis-
covery. It was, in the main, and especially in England,
recognized as proven in his own lifetime, and, again, no
one of credit claimed or asserted the claim of others to
priority. In research, all enquirers stand on steps others
have built up; but in this, the most important of single
contributions to physiology, the credit is Harvey's and

1 Epistle to Dr. Charleton.

William Harvey

From a painting by Cornelius Janssen

William Harvey 295

almost Harvey's alone. His other great work, " Exercita-
tiones de Generatione Animalium," is of secondary import-
ance. It shows marvellous powers of observation and very
laborious research; but although, to a great extent, it led
the way in embryology, it was shortly superseded by the work
of those who had the compound microscope at their command.
The poet, Cowley, a man of wide culture, wrote an " Ode
on Harvey," in which his achievement was contrasted with
a failing common to scientific men of his own time, and,
so far as we can see, of all time : —

" Harvey sought for Truth in Truth's own Book
The Creatures, which by God Himself was writ;

And wisely thought 'twas fit,
Not to read Comments only upon it,
But on th' original itself to look.
Methinks in Arts great Circle, others stand
Lock't up together, Hand in Hand,

Every one leads as he is led,

The same bare path they tread,
A Dance like Fairies a Fantastick round,
But neither change their motion, nor their ground :
Had Harvey to this Road confin'd his wit,
His noble Circle of the Blood, had been untrodden yet."

Harvey's death is recorded in a characteristic seventeenth
century sentence, taken from the unpublished pages of
Baldwin Harvey's " Bustorum Aliquot Reliquiae " : —

" Of William Harvey, the most fortunate anatomist,
the blood ceased to move on the third day of the Ides
of June, in the year 1657, the continuous movement of
which in all men, moreover, he had most truly asserted

"Ev T€ ro< iravTfS KOI cvl Trac

1 The writer is indebted for this quotation to Dr. Norman Moore's
" History of the Study of Medicine in the British Isles," Oxford,
1908. He may here add a short note on the " Tabulae Harveianee,"
presented in 1823 by the Earl of Winchelsea to the Royal College of
Physicians. Sir Thomas Barlow, in his Harveian Oration of 1916,
threw much doubt on these " Tavole " having belonged to Harvey;
and Dr. Archibald Malloch, of the Canadian Army Medical Corps,
has, in his recently published lives of Sir John Finch and Sir Thomas
Baines, brought forward almost conclusive evidence that these
" Tavole " belonged to the former of these two gentlemen, and were
brought by him from Padua, where, with his friend, he had studied
medicine.

298 Britain's Heritage of Science

Among other great physiologists and physicians, the
Swiss, Sir Theodore Turquet de Mayerne (godson of Theodore
Beza), who settled in London in 1611, has left us " Notes "
of the diseases of the great which, .to the medically minded,
are of the greatest interest. He almost diagnosed enteric,
and his observations on the fatal illness of Henry, Prince of
Wales, and the memoir he drew up in 1623 on the health
of James I., alike leave little to be desired in completeness
or in accuracy of detail.

Before bringing to a close these short notices of those
who studied and wrote on the human body, whole or dis-
eased, a few lines must be given to John Mayow (1640-
1679), of Oxford, who followed the law, " especially in
the summer time at Bath." Yet, from his contributions
to science, one might well suppose that he had devoted
his whole time to research in chemistry and physiology.
He it was who showed that, in respiration, not the whole
air, but a part only of the air breathed in, takes an active
part in respiration, though he called this part " by a different
name, he meant what we now call oxygen." *

Mayow showed that dark venous blood is changed to
bright red by taking up this unknown substance, and thus
was very near to discovering oxygen, for he fully grasped
the idea that the object of breathing is to cause an inter-
change of gases between the air and the blood, the former
giving off what he called its " nitro aero " constituent
(oxygen) taking away the " vapours engendered by the
blood." He was the first to find the seat of animal heat
in the muscles, to describe the double articulation of the
ribs and spine, and he discussed the function of the inter-
costal muscles in an entirely modern spirit. Had he been
spared he undoubtedly would have gone far, but he died
in Covent Garden at the too early age of thirty-five, having
been married a little time before " not altogether to his
content."

Thomas Sydenham was one of the first physicians who
was convinced of the importance of constant and prolonged
observation at the bedside of the patient. He passed by

1 Foster, Sir Michael, "The History of Physiology," Cambridge,
1901.

Physiology and Medicine 297

all authority but one — " the divine old man Hippocrates,"
whose medicine rested also on observation. He, first in
England, " attempted to arrive at general laws about the
prevalence and the course and the treatment of disease
from clinical observation." He was essentially a physician
occupied in diagnosis, treatment and prognosis. When he
was but twenty-five years old, he began to suffer from gout,
and his personal experience enabled him to write a classic
on this disease, which is even now unsurpassed.

Francis Glisson, like Sydenham, was essentially English
in his upbringing, and did not owe anything to foreign
education. His work on the liver has made " Glisson's
capsule " known to every medical student, and he wrote
an authoritative book on rickets. He, like Harvey, was
educated at Gonville and Caius College, and, in 1636,
became Regius Professor of Physic at Cambridge, but the
greater part of his life he spent at Colchester.

A contemporary of Mayow was Richard Lower (1631-
1691), of Cornwall. He was the first to perform the operation
of directly transfusing blood from one animal to another.
In 1669 he injected dark venous blood into inflated lungs,
and found it became scarlet. This he attributed to something
which was being absorbed from the air which was being
passed through the lungs. In his " Tractatus de Corde "
he gave a more accurate description than anybody had
hitherto given of the structure of the heart, including its
innervation, and, having at his disposal more exact apparatus,
he was able somewhat to expand and complete Harvey's
exposition of the physiology of that organ.

Lower was for a time assistant to Thomas Willis (1621-
1675), whose name is commemorated by the " circle of
Willis " at the base of the brain. The " Cerebri Anatome "
of the latter (1664) was the most complete and detailed
account of the nervous system that had been published
up to this time, though his hypotheses as to the functions
of the parts he described left much to be corrected later.
In the preparation of this work he had been helped by
Lower and Sir Christopher Wren, who drew the illustrations.
Wilhs was as distinguished a physician as he was a
physiologist.

298 Britain's Heritage of Science

A name that is sometimes overlooked in the history of
British Science is that of Clopton Havers (? 1650/60-1702).
He was for a time educated at St. Catherine's Hall, Cam-
bridge, but left the University without taking a degree.
He took the M.D. at Utrecht in 1685, and practised in the
city of London. But he was an anatomist as well as a
physician, and was the first to give an adequate account
of the structure of the bone, and this in his chief anatomical
work " The Osteologia Nova, or some new Observations
of the Bones and the parts belonging to them." His name
is commemorated by the Haversian Canals, a name which
is still used to designate those smaller channels of the bone
through which the blood-vessels pass.

British animal physiology, which had started magni-
ficently with Harvey, and had continued under Mayow,
de Mayerne and others, was carried forward by Stephen
Hales (1677-1761). He was a born experimenter, and, as
a student, worked in the " elaboratory of Trinity College,"
which had been established under the rule of Bentley, ever
anxious to make his college the leader in every kind of
learning. We have said something about the contribution
of Stephen Hales to vegetable physiology, but he was no
less brilliant as an animal physiologist. In the second part
of his statical essays, entitled " Haemadynamics " (1733),
a real advance is recorded in the physiology of circulation.
Hales invented the manometer, with the aid of which he
was able to make quantitative estimates of blood-pressure,
and measure the velocity of the blood-current. He knew
how to keep blood fluid with saline solutions. He studied
the shape and form of muscles in contraction and at rest,
and had a considerable knowledge of secretion. He worked
much on gases and paved the way for Priestley and others
by devising methods of collecting them over water. Of
him, Sir Francis Darwin writes : —

" In first opening the way to a correct appreciation
of blood-pressure Hales' work may rank second in
importance to Harvey's in founding the modern science
of physiology."

He was a master of scientific method and the greatest
physiologist of his century. There were, however, many

S. Hales, W. Hewson, T. Young 299

others, and Professor Langley has summarized the work
of some of them in his " Sketch of the progress of the
discovery in the eighteenth century of the autonomic
nervous system."1

In the eighteenth century a most distinct advance in
animal physiology was made north of the Tweed by Joseph
Black, whose work in Physics and Chemistry has already
been described (see p. 65). Investigating the properties of
carbonic acid gas or " fixed air," as it was then called, he
noted that " fixed air " is also present in expired air, and
is physiologically irrespirable, though not toxic.

William Hewson (1739-1774), a pupil of the Hunters (see
Chapter X.), became assistant to them, and John Hunter
left him in charge of his dissecting room when abroad with
the army. For a time Hewson was in partnership with
William Hunter. It was he who discovered the existence of
lymphatic and lacteal vessels in birds, reptiles and fishes,
a fact which was of great importance in view of the opinions
held by the Hunters that absorption is the function of these
vessels ; for hitherto the opponents of this view had pointed
to the absence of these organs in the lower vertebrates.
A more important work was embodied in his experimental
enquiry into the properties of blood (1771). Hewson showed
that when coagulation of the blood is delayed by cold or by
the addition of neutral salts, a coagulable fluid may be
separated from the corpuscles. He further showed this
fluid was an insoluble substance which could be precipitated.
According to Hewson's view, coagulation was due to the
formation of this substance which he called " coagulable
lymph," and which we now call " fibrinogen." For a time
his work was forgotten, but now at last its value is fully
recognized.

The Quaker physician, Thomas Young, whose brilliant
work in Physics has been described in our first chapter, was
the founder of the science of Physiological Optics. He
studied under John Hunter, and amongst his early discoveries
he showed that the accommodation of the eye to different
distances is due to changes in the curvature of the crystalline

1 Journal of Physiology, Vol. L., 1916.

300 Britain's Heritage of Science

lens. He gave the first description of astigmatism of the
eye, and showed how it could be corrected by tilting the
lens, through which the object is looked at; but Young
had only come across a slight case of the defect. More
pronounced cases require cylindrical lenses, as subsequently
shown by Airy (p. 120). He also laid the basis of the theory
that colour vision is due to retinal structure corresponding
to red, green, and violet, and applied it to the explanation
of colour blindness. Young advanced Physiology also in
other directions, and in the Croonian Lecture, delivered in
1818, he stated the laws covering the flow of blood to the
heart and arteries.

Thomas Addison (1793-1860), from Cumberland, was a
brilliant pathologist, and owing to his not being a very
successful practitioner, lived almost entirely on his teaching
and hospital work. He was the first to employ electricity
in the treatment of various spasmodic disorders and heart
disease, and, together with John Morgan, he wrote the first
book in our language on the action of poisons on the living
body. He described pernicious anaemia, and in his work
" On the Constitution and Local Affection of Disease of the
Supra-renal Capsules," he described that disorder which is
always associated with his name. This book is now regarded
as the starting point of a long series of studies into the diseases
of the ductless glands.

A third researcher from the north of England was Sir
William Bowman (1816-1892), born in Cheshire, the well-
known ophthalmic surgeon. He contributed much to the
science of physiology. He it was who discovered and
described striated muscle, basement membranes, the ciliary
apparatus of the eyeball; but perhaps he is best known for
his research on the kidney, his theory being that while the
tubules and plexus and capillaries are the parts mostly
concerned in the secretions of urea, lithic acid, etc., the
malpighian bodies were the organs which separated the
watery constituents from the blood.

With the arrival of Michael Foster (1816-1907) in Cam-
bridge as Praelector in Physiology at Trinity College in 1870,
began an era of great activity in biological research in that
ancient University. This subject had been by no means

T. Addison, W. Bowman, M. Foster 301

neglected under Professor Sir George Humphry, Professor
Clark, and others, but Foster brought with him new methods
and new conceptions. Owing to the religious tests demanded
in those times by the older Universities, Foster had been
educated at the University College, London, and after
practising as a country doctor for a very few years, he
became a teacher in Practical Physiology at his old College,
and in 1869 he was elected Professor in succession to Sharpey.
He also succeeded Huxley as Fullerian Professor at the Royal
Institution. For twenty-two years he acted as Biological
Secretary to the Royal Society, and in 1899 he presided over
the British Association at their meeting at Dover, in which
year he was created a K.C.B. In the year 1900 he was
elected M.P. for the University of London, but lost his seat
six years later by the small majority of twenty-four votes;
it makes one shudder to recall that a man of such outstanding
merit should have said : " Not till I became a Member of
Parliament did I understand what power meant."

When the new Statutes came in at Cambridge, a Pro-
fessorship of Physiology was established, in 1883, and Foster
was the first to hold it. He did but little in original research,
but was the cause of a vast amount of research in others.
Still he was to some extent a pioneer in the study of Histology
and introduced the staining of sections with log-wood or
hsematoxylin. H© was notable as a teacher, and founded
one of the finest Schools of Physiology that has ever existed.
He was a brilliant writer and a masterly organiser, and
undoubtedly one of the best lecturers and * after-dinner
speakers in the last quarter of the nineteenth century.

On arriving in Cambridge he introduced courses of
practical demonstrations modelled on those which Huxley
was carrying on at about the same time in London, and from
the first he was surrounded by a brilliant group of students,
amongst whom were Balfour (see page 284), Walter Gaskell,
Sheridan Lee, J. N. Langley, Newall Martin, Sherrington,
George Adami, Henry Head, and many others. Foster's
text-book of Physiology, the first edition of which appeared
in 1876 and was followed by five others, was a classic, and,
although in so changing a subject, it was almost impossible
to keep pace with the advances of a growing science, it

302 Britain's Heritage of Science

was, for its time, one of the most inspiring of authoritative
books. Foster published many other books, all of them
remarkable for clear and scholarly diction and a real charm
of style, for, like so many men of science, Foster wrote the
purest English. The latest of all, " A History of Physiology
during the Sixteenth, Seventeenth, and Eighteenth Centuries,"
has been of the greatest use in the compilation of these chapters.
In 1887 he founded the Journal of Physiology, the first of
its kind in the English language, and remained sole editor of
it till a few years before his death.

His great organizing powers were shown in the foundation
of the Physiological Society and the International Congress
of Physiologists. As Secretary of the Royal Society, he
took a leading part in the establishment of the International
Association of Academies and the International Catalogue
of Scientific Papers. He was a member of numerous Royal
Commissions, and had to a marked extent the ear of the
Government. If Foster told the Treasury a certain thing
ought to be done, it usually was done.

Amongst the most brilliant pupils of Foster was Walter
Holbrook Gaskell (1847-1914), a member of the well-known
Liverpool family to which Mrs. Gaskell the novelist also
belonged. Gaskell came up to Cambridge in 1865, as a
mathematician, at the unusually early age of 17 and some
months. Four years later he took his degree as twenty-
sixth wrangler. He then started to study medicine. A
year later he fell under the magnetism of Foster, and imme-
diately began a series of works which have made his name
one of the best known in the history of modern physiology.

His work falls mainly under three heads. He began his
researches by studying the inner vation of blood vessels in
striated muscles, and was gradually carried on to the investi-
gation of the small arteries of the heart with varying reactions
of the blood. He found that small additions of alkali
increased their tone, and small additions of acid decreased
it, and he was one of the first to recognize that there is a
chemical control in the organs and tissues as well as a nervous
one. Later he turned his attention to the inner vation of
the heart and the cause of the heart beat. At that time it
was held that the nerve cells present in the tissues of the

Michael Foster, Walter Gaskell 303

heart control its beat. But there is some evidence that the
nerves were not the sole controlling cause, and in a series
of masterly papers Gaskell expounded the view of the
muscular origin of the beat, and showed how the beat is
conducted in the four chambers of the heart. Recently
great advances have been made in the application of physio-
logical methods to the clinical examination of the heart, and
this great help to suffering humanity is largely based upon
Gaskell 's work. His studies on nerves led him on to investi-
gate the structure, origin, and connexions of the sympa-
thetic nervous system. He described the relations of these
ganglia with the spinal cord, and gave an accurate inter-
pretation of their mode of action. His last book, the proof
sheets of which he finished correcting the day before the
stroke which ended his life, is entitled " The Involuntary
Nervous System."

In the early nineties he turned away from his normal
work to investigate the action of chloroform on the heart.
A Commission had been formed and financed by the Nizam
of Hyderabad to investigate the cause of death under
chloroform. The Commission reported that death was
usually due to the action of the respiratory centre. On
re-investigating, with the assistance of Dr. L. Shore of
St. John's College, Cambridge, it was found that chloroform
had a direct weakening effect on the heart, and that respira-
tion is not the only factor to be watched when that anaesthetic
is administered.

Gaskell's work had always been rather on the morpho-
logical side, and his third line of enquiry was into the origin
of vertebrates from invertebrates. His work on this subject
is a monument of ingenuity and a monument of patience.
In his view, vertebrates had been derived from some possible
crustacean or arachnid-like ancestor, and his investigations
into the structure and histology of Limulus and of the larval
lamprey added vastly to our knowledge of these organisms.
But in spite of all his ingenuity and all his patient persistence,
he failed to carrry conviction to the heart of his critics, and
all we can say about it is that his theory, like other theories
of the origin of vertebrates from invertebrates, is still
unproven.

304 Britain's Heritage of Science

Gaskell was a man of broad views. Every new fact he
succeeded in establishing he used as a basis for further
generalization. He took comparatively small part in the
management of the University, but from time to time and
whenever really needed, he was willing to place his services
at the disposal of what was considered the reforming party
in University politics.

During the first half of the nineteenth century, Physiology
when it was taught at all was almost invariably taught by
medical men in active practice at the various London and
other hospitals. As a rule the doctor predominated over
the physiologist, and physiology in those days was not so
clearly defined a science as it has since become. Perhaps
the most outstanding name of this period is William Sharpey
(1802-1880). He was educated in Edinburgh, and was a
pupil of Dr. John Barclay, Extra-mural Lecturer at that
university. He subsequently studied at Paris. On re-
turning to England he started a private practice, but he
lacked a good bedside manner, and was obviously unsuited
for the duties of a practitioner, so from 1826 onwards he
devoted himself entirely to pure science. He spent some
years abroad trudging the roads in true medieval style from
one university town to another in Central Europe, and in
1829 he established himself as a teacher in Edinburgh. Later
he succeeded James Quain as Professor of Anatomy and
Physiology in what was then the University of London, and
is now known as University College, Gower Street, and here
for the first time a complete course of lectures on Physiology
were delivered by one who was purely a physiologist. He
was a born teacher, and his lectures were models both in
matter and form. For a time he was Secretary to the Royal
Society and a member of the General Council on Medical
Education and Registration.

Sharpey was a master of sound judgment, extraordinary
memory, and one who could deeply interest his pupils in the
subject he had at heart. Amongst his scholars were Michael
Foster and Burdon Sanderson, the latter of whose work at
London and Oxford notably carried on the tradition of his
master. Although Sharpey was a man of force and power
he, like Michael Foster, was perhaps more instrumental in.

W. C. Sharpey, L. C. Wooldridge 305

getting published the work of his students than of publishing
his own; but the few papers, which are enumerated in the
" Dictionary of National Biography " under his name, are
papers of permanent value.

We have mentioned before that men of science were less
specialized at the earlier part of our period than they have
now become. Even the holding of professorial chairs in the
earlier part of the nineteenth century usually involved
teaching in more than one science. Up to the year 1866,
the professor of anatomy at Cambridge was responsible for
the teaching of zoology as well as for that of anatomy. In
many other places, the professorship of zoology was respons-
ible for what teaching there was in animal physiology, as
at Manchester, where W. C. Williamson combined the chairs
of botany, geology, zoology and animal physiology. In the
London hospitals, strictly scientific subjects were taught by
doctors in practice who were on the staff of the hospital.

It is quite impossible to detail the varied and successful
activities of the numerous physiologists who have worked
during the last forty years. Conspicuous amongst them was
Wooldridge. He was a pioneer. He was convinced that
many of the chemical and quasi-chemical problems presented
by the processes of life had been attacked too much by
laboratory methods remote from the animal itself. He
turned to the coagulation of blood as a type of such processes,
and decided that an analysis of the phenomenon must involve
observations upon the reactions offered by the living animal.
He developed the technique of injecting extracts of tissue
and organs into the circulation, and rapidly obtained results
which gave new conceptions to physiology.

He did not live to produce a finished theory of blood
coagulation, but it is not too much to. say that his work
initiated the modern studies of immunity, and was the
foundation of what is almost a new science.

It is not proposed to enter into the consideration of the
enormous advances that English men of science have con-
tributed to the practice of medicine and the alleviation of
pain. Sir James Young Simpson (1811-1870) discovered
chloroform, thereby immensely improving the possibilities
of operations, and to a quite unbelievable extent reducing

306 Britain's Heritage of Science

pain, not only of our poor suffering humanity, but of the
animal creation. Edward Jenner (1749-1823) led the way
with vaccines and for the first time introduced the practice
of preventive innoculations. Sir Charles Bell (1774-1842)
cleared up the relations between the functions of the anterior
and posterior roots of the spinal column, and made numerous
other discoveries on the nervous system; and Lord Lister,
whose father had almost re-invented the compound micro-
scope, made many discoveries, by far the most important
of which war* his definite discovery of the part played by
micro-organisms in wounds. The antiseptic principle in
the practice of surgery dates from him and from his time, as
Dr. F. H. Garrison says, " when his body was laid to rest
in Westminster, England had buried her greatest surgeon."

It is impossible to deal with more than but a very few
of the distinguished physiologists who were working at the
close of the last century. One of these, however, must be :
Charles Smart Roy (1854-1897), who was educated at
St. Andrews and the University of Edinburgh. He fought
through the Turco-Serbian War, and whilst in Epirus
invented his frog cardiometer. For a time he was assistant
at Strassburg University, and here it was that he invented
the instrument which is best known in connexion with his
name, the Renal Oncometer, for the study of the variations
of the blood-flow through the kidney. Later, as George
Henry Lewes Student, he worked with Foster at Cambridge,
and in 1884 was elected to the Fellowship of the Royal Society,
and shortly afterwards was appointed first Professor of
Pathology in the University of Cambridge.

Hampered by ill-health and by want of accommodation
at the laboratory, he nevertheless produced work of great
value, and he succeeded in training a number of students
of great eminence, amongst whom J. G. Adami, W. Hunter,
Alfred Kanthack, Lorrain Smith, W. Westbrook, and Lewis
Cobbett, deserve record.

With Adami he carried out a long series of researches on
the mammalian heart, which involved the invention of the
cardiac-plethysmograph and the cardio-myograph, which
greatly helped to overcome the mechanical difficulties of the
subject. But he by no means confined his attention to this

E. Jenner, J. Lister, C. S. Roy 307

branch of pathology. He had been instrumental in checking
a cattle plague in the Argentine Republic by protective
inoculation, and in 1885 proceeded to Spain to investigate
an outbreak of cholera which threatened to be serious.

As a lecturer he showed little interest in his pupils, but
to a researcher he was kindness itself, and unremitting in
his helpful aid. He was one of the few who at that time
were convinced that aviation was coming, and he made
several experiments on flying machines.

U 2

308 Britain's Heritage of Science

CHAPTER XII
GEOLOGY

IN tracing the progress of any line of scientific research
it very often happens that our enquiries are largely
centred round the life of one man. It may be that he has
only collected and put into shape ideas which have been
growing in men's minds when at last a flash of genius has
illuminated the paths of research and the wisdom of many
has been crystallized by the wit of one.

It may be that a fortuitous display of phenomena not
before exhibited has appealed .to the imagination of men, or
combinations of opportunity and talent have started local
intelligence upon the paths of observation.

The striking variety and obvious relations of surface-
features and rock-characters in England have undoubtedly
had much influence in starting geological observations in
this country. England is only a small bit of the contorted
western margin of the uplifted Eurasian continent. The
great folds which brought it all up within reach of denudation
are traversed here and there by belts of more sharply
crumpled rock which give pause to the periodically encroach-
ing seas. More than one such system of plications has pro-
duced the frilled edge of western Europe with its association
of harder and softer rocks and has thus formed the natural
breakwaters which have held back for untold ages the
tremendous billows of the Atlantic Ocean hurled against
them by the South- West winds. In tracing the progress of
English Geology by reference to the lives of those who have
done most to promote it we shall soon find that it was seldom
mere accident that started them on their way.

We cannot satisfactorily discuss the influence of indivi-
duals upon Geological discovery without realising that

William Smith 309

and's place on the globe and consequent geographical
;res have made her a Geological microcosm in which
almost every known formation is represented in some part
of the surface, and that the secrets of her structure and history
are best disclosed in the mountainous regions of Scotland,
the Lake District, and Wales, rather than in the less disturbed
and more regularly disposed strata of the eastern and southern
counties. It has thus been in the more complicated regions
of the north and west that most of her prominent geologists
have been born or have found the sphere and stimulus of their
investigations.

Many a surveyor had observed the obvious fact that as
we proceed across the country various kinds of rock appear
at the surface one after another, and these have been laid
down on plans and maps for economic purposes; but the
careful work and shrewd intelligence of William Smith
(1769-1839), in the beginning of the nineteenth century,
led him to infer that these did not lie side by side like the
pieces in a Chinese puzzle, but rested on one another like
the tiles on a roof in regular succession, and that older rocks
crept out below the newer layers in a constant order. Here
we had the principle and mode of succession of rocks once
and for all established.

This, however, was not all that we owe to William Smith,
for though fossils had been previously collected he now
discovered that different plants and animals which lived and
died and were buried in the rocks were characteristic of
different beds and were followed by different forms of life,
and that the difference in these fossil remains enabled him
to detect to which formation of the adjoining district an
isolated patch of rock was most related.

Here we find the recognition of a chronological sequence
of the stratified rocks and of the possibility of identification
by means of the organic remains contained in them. The
first account of this discovery that every bed contained
characteristic and peculiar fossils by which it could be
identified was issued in 1799 by William Smith, and in
1815 he embodied the results of his twenty years of obser-
vation in the field in the first Geological Map of England
and Wales and part of Scotland. His work appeared to

310 Britain's Heritage of Science

Sedgwick of such fundamental importance that he called
Smith " the Father of English Geology."1 The majority
of the names, Lias, Gault, Clunch, etc., which he applied
to the sedimentary formations in England, were only
names used by local workmen for certain kinds of deposit,
but they have been retained and are now the alphabet of
stratigraphical classification throughout the world.

As the work of examining the visible crust of the earth
proceeded men must often have raised the question how did
Nature bring about these vast changes ?

Dr. James Hutton (1726-1797), who in qualifying himself
for the Degree of Doctor of Medicine had familiarized himself
with the methods of scientific research, had many interesting
questions forced upon his notice in the cultivation of his estate
in Norfolk. These he attacked by strict inductive methods,
but the theory which has always been most especially asso-
ciated with his name and which now forms the foundation of
geological research relates to the manner of the building up
of the crust of the earth and the production of its subse-
quent modifications. These, he contended, had been brought
about by agents and processes still seen in active operation
somewhere on the earth, and in 1785 he communicated to the
Royal Society of Edinburgh these conclusions. John Playfair
(1748-1819), his pupil, published in 1802 his classic work
entitled " Illustrations of the Huttonian Theory of the Earth,"
and demonstrated the igneous origin of granite and the work
of the agents of erosion in the production of scenery. It often
happens that a disciple of the originator of a new idea says
and writes more in defence of the theory than the original
author himself. We heard more about evolution from
Huxley than from Darwin.

Many fierce controversies arose around and about the
principal matters in dispute between Huttonians and Wer-
nerians as to the relative importance of fire and water in
geological phenomena, all of which have had the useful effect
of turning men to seek facts from Nature in support of their
own several views.

The school of Catastrophists which had indulged in wild

1 Proc. Geol. Soc., Vol.

'

i

Charles Lyell

From a daguerreotype by J. E. Mayal

J. Hutton, J. Play fair, C. Lyell 311

speculations on the causes of changes in the earth's physical
and organic history had their fallacies exposed by the work
of the successors and followers of Hutton and Playfair. For
from the seed sown on English soil by these two pioneers
sprang the sound healthy tree of Uniformitarianism throwing
out many branches brightened often by the flowers of genius
and eloquence, laden with the rich fruit of patient research
and honest criticism, sometimes warped by opposing acci-
dents but always deep-rooted and sound at the core. Many
a good workman helped to till the soil, but one name stands
out in bold relief over the entrance to the garden of English
Geology. Sir Charles Lyell (1797-1875) was a barrister who
turned to geology when he found that an increasing weakness
of sight prevented his following other pursuits for which he
had been more specially trained. Lyell is the man to whom
English Geology owes most. For half a century he supported
the Uniformitarian theory, training the growing plant,
checking unwholesome growths. Lyell watched the progress of
research into the modern changes of the earth and its inhabi-
tants, distinguished the true from the false, and dismissed
the evidence for that which was not yet proven. His great
work entitled " The Principles of Geology " was first pub-
lished in 1833, and its publication marks an epoch in the
history of Geology.

It is a long and winding way from the region of specu-
lation in which Werner and his disciples here and abroad
sought to find out how basalts were precipitated out of
an aqueous mixture, to the hardly won ground on which
Alfred Harker and his friends and pupils now urge with
persuasive accumulation of experiment and observation how
each ingredient was segregated according to its affinities
out of the eutectic magma which is now regarded as an
inferential fact.

Many strong men helped on the work, some, like
Dr. Samuel Allport about the beginning of the 70's, quietly
collecting material, others, like David Forbes, testing and
criticising and giving out freely in discussions from the vast
stores of knowledge thus acquired, others teaching and writing
like Teall, to whom we owe the first text -book on British
Petrography.

312 Britain's Heritage of Science

Much of the research falls within the sphere of Chemistry,
but it is to the mi loscope and its accessories that we owe
most of the advances made.

Henry Clifton Sorby (1826-1908) may be regarded as the
pioneer along this line. He read a paper on the subject before
the Geological Society in 1857 describing the structure of
crystals as giving an indication of the origin of minerals and
rocks. These he studied by means of thin slices, a method
which he had previously, in 1850, applied to the study of
limestones. Sorby was followed by the Rev. Prof. Bonney,
an accomplished scholar and keen controversialist, who
grasped at once the value of these new instruments of
research, vindicated Sorby, and by his academic teaching
and writings brought the new methods into the prominent
and popular position which they now occupy.

" La paleontologie suive les marteaux 5>1 was a phrase in
which it was sought at a recent International Geological
Congress1 to point out that it generally happened that the
collections of fossils which have furnished the materials for
comparative study or for the discrimination of important
series of strata owed their existence to the accident that they
were obtainable round the home of some keen investigator
who, working single-handed or gathering round him a band of
like-minded friends, had availed himself of his special oppor-
tunities. In this way all available exposures in the district
were well searched ; the strata were called after the localities
where they were first or best seen, and genera and species were
named after some one whom it was desired to honour or
some character that appeared distinctive. In offering a
comparative sketch of the development of stratigraphical
research in Britain we may take the names of the pioneers
alphabetically, chronologically, or topographically, and the
above considerations will soon convince us that a bio-
graphical sketch of the founders leads us at once to a con-
sideration of the locality in which their discoveries were
made. We can hardly select a better example in illustration
of this than the district round St. David's. Here the oldest
rocks in the British Isles were seen, folded and contorted it

1 Rept. International Geol. Congress, Petrograd,

H. C. Sorby, H. Hicks 313

is true, but still revealing a definite order of succession among
the varieties of lithological character. There are there older
granitoid masses succeeded by overlying volcanic series.
Dr. H. Hicks (1837-1899), a young local medical practitioner,
attacked this difficult problem in the latter half of the
nineteenth century, and gave the latinized local names of
Dimetian and Pebidian to the two principal divisions. Pro-
fessor Bonney, E. B. Tawney, and others soon took up the
work and were in time able to draw up a sketch of the history
of that early metamorphic series. Similar rocks were dis-
covered elsewhere in the same position with reference to the
fossiliferous formations and, though differing in details, were
easily co-related with the typical series of St. David's. These
had been noticed by earlier stratigraphical geologists, but
were passed over with only a short description. There was,
however, little doubt about the Archaean Rocks (as they
came to be called) of North Wales, of the Midlands, where
they have been described by Callaway and others, and of
North -West Scotland, where a new difficulty was introduced
by the wondrous earth movements which left these as well as
some newer rocks folded, broken, displaced, and crushed,
often beyond recognition. The researches of Dr. Hicks and
his able exposition of his progressive views on the Archaean
Rocks are sufficient to prove what geologists owe to the
accident of his residence at St. David's; but there was yet
more left for him to discover. Resting upon the denuded
surface of the Archaean Rocks were the Basement Beds of
the Cambrian separated from the pre-Cambrian Rocks by
a vast interval of time. The Survey had passed over the
district without detecting any trace of fossils in these beds,
but Hicks resided there, and his hammer left little untried.
He found fossils in these early Cambrian beds and, incited
to closer search, he found them in lower and lower beds till
there was hardly any horizon from which he had not pro-
cured new species and new genera. This brought Salter,
one of the most acute of palaeontologists, to his side. These
unexpected discoveries are recorded in the name given to a
trilobite, seventeen inches long, which was called Paradoxides
Davidis, the specific name connecting it with St. David's.
The subdivisions in which these various forms occurred

314 Britain's Heritage of Science

were named from the localities where they were first or best
revealed to the hammer of the geologist, and so the lists of
the earliest fossiliferous rocks and their fossils are filled with
names dear to the tourist and the artist.

The correlation of these by means of their fossils with
the rocks exposed in other areas rapidly followed, as, for
instance, by David Homfray, at Portmadoc, and soon the
unexpected Paradoxides and its associates were recognized
among the lowest beds of the fossiliferous rocks all the
world over.

Other systems were determined in course of time : the
home of T. T. Lewis (1801-1858), of Aymestry, is still marked
by the Aymestry Limestone, while the position of the Llan-
dovery Rocks as now defined by the Survey was determined
by Dr. Williams, of Llandovery. The Llandovery Rocks were
subsequently cut off from the Caradoc Sandstone, and their
true position correctly fixed by Sedgwick under the name
May Hill Sandstone. A region so full of promise as the
borderland of Wales attracted Sir Roderick Murchison (1792—
1871), who, in the first half of last century, collated the
evidence and gave to the world in 1893, in his magnificent
work, the Silurian System beautifully illustrated by Sowerby.
The name Silurian is derived from the Silures of South Wales,
the ancient tribe which so long withstood the invading
Romans.

In the meantime Prof. Adam Sedgwick (1785-1873),
stimulated by the work of Jonathan Otley in Cambria, and
with a personal acquaintance from childhood with the rocks
of the North of England, was attracted by the charms of a
wild and almost unexplored country, and threw all his energy
into the work of unravelling the succession of stratified rocks
exposed hi the mountains of Cambria. His results were given to
the world in papers published by the Geological Society during
the same period and in other works in which the fossils were
figured and described by Salter and McCoy. It is to Sedgwick
that Geology owes the name Cambrian for the oldest known
group of fossiliferous rocks; and it was his genius which
introduced order into our knowledge of the older Palaeozoic
rocks of the North of England and W7ales, and laid the founda-
tions for subsequent work in the complicated regions where

R. Murchison, A. Sedgwick, H. Delabeche 315

they are developed. Sedgwick 's influence on the modern
school of geologists is difficult to overestimate.

At the close of the Silurian Period there was an irregular
sinking of the land. The old surface was worn down and the
material for new lands built up from the products of the
waste. England was in the region of most constantly recurring
movements ; and it so happened that during the period that
now supervened the British Isles formed part of the margin
of Eurasia, in which there were more limited hydrographical
areas. In one place corals grew in bright clear water, while,
not far off, lagoons and swamps favoured the growth of a rich
semi-tropical vegetation, with a fresh or brackish water fauna
in which fish abounded. The beds with this later facies
received the name of Old Red Sandstone. Local geologists
were led to study the exceptionally rich deposits which
occurred near their homes, and thus the fishes of the Old
Red Sandstone in Scotland arrested the attention of Hugh
Miller, one of whose fascinating books was a description of
this formation.

Sir Henry Delabeche (1796-1855) was attracted to the
tongue of land which runs out to meet the Atlantic on our
south-west coast. He recognized that mapping, mapping,
mapping, was the chief essential for the understanding and
recording of the geological structure of a country. He long
worked single handed at the district, and published treatises
and memoirs which are still classic works. But his crowning
achievement was the establishment of the Government
Geological Survey, which has developed into a great school
of geological research, and proved the model on which all
similar institutions have been organized.

John Phillips (1800-1874), the Oxford Professor of
Geology, was born on the great rim of rocks which hold the
South Wales Coal field as in a basin. From its swelling hills
and crags it was called the Mountain Limestone, a name by
which it is still commonly known. Phillips was drawn away to
Yorkshire, where he soon found himself on the very same
Carboniferous rocks, on which, as well as on the secondary
rocks which succeeded them, he wrote admirable treatises.

The nomenclature followed the hammers of these leaders
of research, but now, alas, students cannot avail themselves

316 Britain's Heritage of Science

as fully as they might of these geological classics, because
hardly any of the fossils retain the name originally assigned
to them. Names, instead of being regarded as a means of
recalling the forms referred to, have become a means of
forcing on the world new theories of classification which have
to be changed again when later authors are impressed by
the value of other similarities or differences.

In the working of coal mines and quarrying of limestones
of the Carboniferous formation opportunities are offered to
the hammers of the palaeontologists and stratigraphists to
follow the exposed rocks, and so we find the same story
repeated. Witham, Binney and Williamson collected the fish
and the plants from the coal measures near Manchester;
and Lindley and Hutton devoted their attention to the study
of the vegetable remains

At the close of the Carboniferous period there again
ensued a period of local destruction of older beds, followed
by the deposition of fresh rocks of the New Red Sand-
stone. Vast movements of continental masses were taking
place and hydrographical areas became still more limited
in extent and consequently more varied in their results. So
much, however, did they present a general uniformity
in the character of the sequence and in their prevailing
colour that these basement beds of this new system,
the so-called Poikilitic or Variegated series of Phillips, came
to be known as the New Red Sandstone. The lower part
gave rise to much controvers}^, as it was by some con-
sidered the equivalent of the Permian of Russia, and by
some bracketed with the underlying Carboniferous rocks.
Passing by these details of classification we find that the
study and nomenclature of these deposits in parts of England
were determined by the home of Charles Moore (1815-1881),
near Gloucester and Dr. E. P. Wright (1834-1910), at
Cheltenham. W. H. Fitton and G. A. Mantell in the South
of England elucidated the sequence of relations of the Jurassic
and Cretaceous beds and utilized their local opportunities of
adding to our geological knowledge of these formations and
their fossils.

Thus we see that biographical notices of the early geo-
logists carry us to their homes round which the recreations of

Palaeontology 317

leisure hours enabled them to work out in detail the succession
of the rocks and the distribution of their organic remains.
The names attached to the formations and now in common
use throughout most of the world prove that England has
contributed most largely to the establishment of the sequence
of events in the earth's history and to laying the foundations
of a rational system of classification of the strata.

Amongst the Tertiary rocks Sir Joseph Prestwich (1812-
1896) and Edward Forbes (1815-1854) traced the succession
of beds particularly in the London and Hampshire basins
and demonstrated the value of the now generally adopted
terms Pleistocene, Pliocene, Miocene and Eocene which Lyell
had first applied early in the last century.

Much good work has been done by British Palaeonto-
logists apart from the collecting of fossils in the field, where
Palaeontology is the handmaid of Stratigraphy.

For instance, Thomas Davidson (1817-1885) during the
last decades of the nineteenth century was examining and
comparing the Brachiopoda which played so large a part in
the life-history of the older rocks, while field geologists far
and near sent up to him the results of what their hammers
had yielded, thus supplying him with more and more material
and availing themselves of his every ready and untiring
help to discriminate between zones by means of their fossils.

Edwards and Haime did the same for corals. J. W. Salter
(1820-1869) had established many of the recognized genera
of trilobites in the course of his investigations of the faunas
of the older rocks between the years 1840 and 1855.
McCoy's labours covered a wide field, but his chief work lay
amongst the fossils of the older rocks. To James de Carle
Sower by (1787-1871) we owe many of the names of fossils
which have a cosmopolitan distribution. Sir Richard Owen's
(1804-1892) researches amongst fossil vertebrates gained him
the reputation which was due to his remarkable acumen and
minute knowledge of anatomy.

While pointing out where, how, and why British geologists
were pressing on special research we must not forget those
who, having acquired wide and accurate knowledge of many
branches, have collected and sifted the evidence and given
the results of their labours in the form of text-books, and

318 Britain's Heritage of Science

memoirs to which students may turn for the latest and most
up-to-date views on each advancing front. Here we must
mention the two Geikies. Dr. James Geikie (1839-1915),
besides valuable memoirs on general geology, has given us
a summary of the arguments in favour of a correlation of
astronomical cycles with geological periods. Sir Archibald
Geikie has in text-book after text-book met the wants of
every age, and, in the clear and attractive language which
Scotsmen seem to have by nature, or to have evolved the
method of acquiring by education, has kept generations of
students supplied with accurate information as to the state
of the evidence on the many questions raised in the progress
of an advancing science.

This may be called an age of text-books, many of them
entitling their authors to a foremost place among those
who are helping on the progress of science, but we cannot
here even give a list of their names.

We are too apt to attach such importance to our modern
theories that we forget what a great advance an earlier
hypothesis had often made on pre-existing views. It was a
shrewd observation which induced the clever and courageous
Dean Buckland (1784-1856) to maintain that a large part
of the superficial deposits which are seen heaped up on the
tops and flanks of the highest hills and filling the deepest
valleys of the North of England must have had an entirely
different origin from the alluvial deposits such as we see
being laid down now, and to venture on the bold suggestion
that there had been in quite recent times a great sub-
mergence and that the sea once swept over the land and left
as the result of the deluge these tumultuous deposits hence
called Diluvial.

Wider travel and more detailed work, however, showed
a closer analogy between most of these so-called Diluvial
formations and the masses of debris carried on, in, or under
the ice and left at its foot when the glaciers or ice sheets
melted. Agassiz pointed this out and a grand company of
Scotch and other geologists immediately set to work on the
details of every section to prove or disprove the truth of
each new suggestion.

In the domain of Economic Geology William Smith's

Economic Geology 319

observations were primarily connected with the question
of soils; while Farey's descriptions in 1811 and 1813 of the
Derbyshire Coal Measures and lead mines and of the dis-
location of the strata were of practical value. To questions
of water-supply Prestwich's attention was specially drawn,
and the possible extension of the Coal Measures beneath the
South-East of England was maintained as far back as 1855
by Godwin Austen, whose geological conclusions have now
been verified.

The energy of geologists still living amongst us does not
slacken and the reputation of British workers in this branch
of science is well maintained, while the application of the
results of geological research to economic purposes is having
an ever-increasing stimulus given to it.

INDEX

(Where proper names occur more than once, the principal entry, generally
containing a short biographical notice, is printed in italics)

PAGE

Abel, Sir F. - 199,202

Abernethy, J. - - 264

Aberration of light - 62, 70

Abney, Sir W. - - 160, 173
Absorption, spectrum analy-
sis - - 155-9
Academie des Sciences 97, 1 15, 120
Achromatism of lenses 98, 99
Acoustics, see under Sound.
Adami, J. G. - - 301, 306
Adams, J. C. - 125-7
Addison, T. - - 300
Aeronautics :

First hydrogen balloon 68
Glaisher's balloon as-
cents - - 176
Roy's experiments - 307
Agassiz - - 318
Agriculture - - 252,253
Air:

Boyle's law - 75

Composition of - 85

Liquid - - 213

Airy, Sir G. B. - - 70, 119, 126
Astigmatism - - 120
Organization of observa-
tories - 165
Aitken, J. - 176
Alizarin colours - 163, 200
Alkali, manufacture of - 194
Allman, G. J. - - 282
Marine research - - 292
AUman, Prof. W. - - 254
Allport, S. - 311
Alluvial deposits - - 318
Alpha particles - - 184
Anaemia, pernicious, dis-
covery of - - - 300
Analytical Society - - 117
Anaxagoras - - 14
Anaximenes - " - - 8

PAGE

Andrews, T. - - 139, 140
Angout, A. 95

Aniline dye discovered 200, 201
" Animal " electricity - 106

Anti-septic surgery - - 306
Apjohn, J. - - - 176

Arago - - 19,119,126,140
Archer, F. S. - - 173

Archibald, E. D. - - 176
Arctic expeditions, see under

Expeditions.

Argon, discovery of - - 181
Aristotle - - 14,216

Arrhenius - 146

Asclepiadeas - - 244

Ashmole, E. - - 261

Ashmolean Museum, founda-
tion of - 261
Astigmatism, discovery of 120, 300
Atom - - 14
Atomic Theory - 15
Numbers - - - 185
Austen, G. - 319
Ayrton, W. E. - - - 193

Babbage, C.
Bache, Dr.
Bacon, F.
Bacon, R.
Baily, F. -

117,118

- 159

- 223

7,8,218
162, 208

Baines, Sir 1., footnote - 295
Balloons - - - 68,176
Balfour, F. M. - 277, 284, 301
Balfour, J. H. - - 254

Banks, Sir J. - 116, 241, 243

Founding of Royal In-
stitution - - 213

Agricultural research - 238
Barrow, I. ... 49

322

Index

PAGE

Barclay, J. - 265
Bartolomaeus Angelicus - 217

Basement membranes - 300

Bateman, S. - 217

Be"champ - - 200

Becquerel, H. - - 183

Beddoes, T. - - 110

Bell, Sir C. - 306

Bennett, A. - 80

Bennett, C. - - - 173

Ben Nevis Observatory - 176

Bentham, George - 245, 246

Berkeley, M. J. - - 250

Bernard, E. 49

Bernoulli, Daniel - - 33

Berryman, Lieut. - - 291

Berzelius - 150

Bessemer, Henry - - 187

Beta particles - - 184

Bevis, J. - - , - 81

Binney, E. W. - - 316

Biometrics - - 286

Bird, J. - - 97
Birmingham University - 160
Black, J. - -14,55-^,130,299

Bleaching - 195

Bliss, N. - - 63
Blood:

Circulation of - - 294
Coagulation of - 299, 305
Pressure, first estimates 298
Transfusion of, dis-
covery - - - 297
Bolton, W. B. - - 173
" Bone-digester " - - 101
Bonney, T. G. - - 312,313
Boscovich - - 70
Botany - - 229-255
Cryptogamic - - 250
Boulton, M. - - 103
Bouvard, A. - 126
Bowman, Sir W. - 300
Boyle, R. - - 1 4, 73-6, 124,288
Boyle lectures - - 74
Boyle's law - 75
Boys, V. - - 87
Bradley, J. - - 61, 70, 97
Bragg, W. - - - 184
Brahe, Tycho » •? 5?

PAGE

Brain, circle of Willis, dis-

covered -

- 297

Bramah, J.

- 105

Bramah lock

- 105

Brande, W. T. -

39, 198

Brewster, D. - 69,

119, 124,

131, 156

Briggs, H.

- 48

Brinkley, J.

- 136

Brisbane, T.

- 253

British Association

132, 214

British Museum

266, 267

Brouncker, Lord

- 51

Brown, Crum

- 133

Brown, R.

243, 255

Brownian movement -

- 244

Brunner & Mond

- 198

Buchan, Alexander

- 176

Buchanan, J. Y.

- 291

Buckland, W. -

- 318

BufTon

- 262

Bunsen - - 149,

150, 157

Cables, submarine - 189, 190,
291, 292

Caius, J. - - 219,257

Calculus - - 53

Cambrian formation - - 314
" Canon Mirificus " 7

Canton, John - - 80, 205
Capillaries, discovery of - 294
Capillarity - 83, 131

Carbonic acid, discovery of 66

Condensation of - - 140
Carboniferous formation - 316
Cardio-myograph - - 306
Cardiac-plethysmograph - 306
Carlisle, Sir A. - - 107

Carnot, Sadi - - 27, 29
Carpenter, W. B. - - 289
Castner - - 194

Castner-Kellner process - 198
Catalytic action - 146

Cauchy - - 122

Cavendish, Lord C. - - 83

Self -registering thermo-
meters - - - 288

Index

323

PAGE

Cavendish, Henry 14, 69, 73, 83-6
Density of earth - 87

Law of inverse square- 81
Meteorological observa-
tions organized - 208
Cawley - - 101

Cayley, A. - 128, 129

Cells, nucleus of - 244

Challis, James - - 126, 127
Chambers, R. - - 275

Chance, Messrs. - 172

Charles II., interest in

science - - 57, 203, 227, 233
Chemical Society - - 212
Chemistry, industrial appli-
cation - - 194-202
Chloroform, discovery of - 305
Action on heart - - 303
Chrystal, G. - 133
Christy, S. H. - - 147
Chronometer - 96
Chromosphere, spectrum of 171
Ciliary apparatus of eyeball 300
Circle of Willis - - 297
Circles, divided - 96, 97
Circulation of blood - - 294
Clarke, A. R. - - 176
Clausius, R. - - 28
Clifford, W. K. - - - 147
Clift, W. - - - - 265
Clifton, R. B. - - 151
Clocks :

Anchor escapement - 95
Temperature compen-
sation - - 96
Coagulation of blood - 299, 305
Coal-tar industry, history of

199-201

Cobbett, L. - - 306

Coherer - - 191

Coke tower condenser, in-
vention of - 197
Colloids - - 145
Colour :

Dispersion - -54, 98

Photography - - 173
Thin plates - 19

Vision - - 128, 300
Comet, Halley's - . 59

PAGE

Common, A. A.- - - 170
Compass :

Early knowledge of 3

Improved by Airy - 121

Conductivity, see under Heat.

Conservation of energy 8, 22, 135

Cooke, Sir W. F. - 188

Cooper, A. - 264

Coral - 317

Cordite - - 202

Corporation of Surgeons - 265

Corpuscular theory of light 17

Cotes, R. - 56

Coulomb - 69, 70

Courtois - - - 115

Crabtree, W. - - 88, 89, 95

Crawford - - 131

Critical temperature - 140

Crookes, Sir W. - - 151,199

Electric discharge - 181

Radiometer - 180

Thallium, discovered - 159

Cruikshank - - 113

Cryptogamic botany - - 250

Crystalline structure - 130, 312

Crystallography - 130

Cugnot, N. - - 104

Cullen, William - - 65

Curie, M. and Mme. - - 183

Cuvier - - 115, 265, 282

On organization of Royal

Society - - - 212

Daguerreotype -

- 173

Dalton, J.

- 15, 36, 40

Daniell, J. F. -

- 147

Darwin, C.

267-281, 286,

246, 248

Darwin, E.

- 268, 274

Darwin, F.

- 236

Darwin, G. H. -

- 177, 178

Darwin, R. W. -

- 268

Daubeny, C. G. -

- 251

Davidson, T.

- 317

Davy, Sir H. -

21, 37, 109, 172,

210, 213

X2

324

Index

PAGE

Davy's lamp - - 116

Deacon, H. - 198
" De Different/us Animal -

ium" - - 257

Degradation of energy - 30

Delabeche, Sir H. - - 315

Delambre 60, 63

De la Rive - 39

DelaRue, W. - - 169

De la Tour, C. - - 140

Deluc - - 66

De Mayerne, Sir T. T. - 296

Democritua - 14

De Morgan, A. - - 143

Desaguliers, J. T. - - 71
Descartes, R. - - 12, 49, 120
Dewar, Sir J. :

Cordite, invention of - 202
Liquefaction of gases 140, 213
Solidification of hydro-
gen - 146
Spectrum analysis - 159
Diamond, nature of - - 115
Differential calculus - 49, 53
Notation - - 117
Diffraction - 19
Digby, Sir K. - - 225
DiUenius, J. J. - - 251
Diluvial deposits - 318
Dispersion of colours- 58, 98
Dissipation of energy - - 29
Dodo - 261
Dollond, J. - 98, 205
Dryander - - 242, 244
Dufay - - 79
Dyeing industry 194, 199-201
Dyer, G. - - 197
Dynamo machine - 192, 193

Earth:

Density of -
Tremors

Earthquakes

Ebonite -

Edwards, A. M.

- 64, 86, 87

- 214

- 88

- 190
140, 292, 317

PAGE

Electric arc - - 114

Battery - 106, 147, 163

Spark - 78

Telegraph - - 187-189

Theories 31, 33, 79, 81, 182

Units - - 214

Electricity, atmospheric - 205

Conduction of - -71,78

Discharge through gases 78,

85, 182

Early researches 5

Frictional - -80,81

in Fishes - - 83

Industrial applications

of - - - 187-194

Law of inverse squares 69, 81

Medical applications - 300

Electrolysis - - 21, 107

Electrolytic production of

metals - - 113

Electro -magnet, invention of 148
Electro -magnetic :

Induction - - 20, 191
Theory of light - 32, 138
Electro -magnetic engine - 24
Electrometer - 70

Electron theory 138, 139, 182

Electroscope, gold leaf - 80
Electrostatics - - 31, 81, 82
Ellis, Capt. - 288

Embryology - - 284, 295
Energy :

Conservation of 8, 22, 28, 135
Dissipation of - 29, 30

Kinetic - - 23

Potential - 23, 123, 135
Transmission of - - 161
Engine :

Dynamo - - 192

Electro -magnetic - 192

Steam - 99-105

Ent, Sir G. - 226

Erosion, geological effects - 310
Eskdalemuir observatory - 209
Eugenics - - 277, 280, 286
Euler - - 98

Evelyn, J. - 220, 225, 226

Evaporation, cooling pro-
duced by - - 65

Index

325

Ewing, J. A.
Expeditions :

Antarctic -

Arctic

Beacon

Beagle

Bulldog

PAGE

- 193

247, 288
207, 288

- 289

- 271

- 291

Central America, God-

man and Salvin . - 293
Challenger - 283, 290, 291
Cyclops - - - 291
Endeavour • • 241, 242
Erebus - - 247, 289
Lightning - - 289

Porcupine - - - 289
Racehorse - - 207

Rattlesnake, Huxley - 282

Foucault -
Fownes, G.
Fox, W. D.
Frankland, E. -
Franklin, B.
Franklin, Sir J. -
Fraunhofer
Freezing mixtures

PAGE

- 156

- 146

- 270
148, 149

79, 205

- 289
155, 156

- 76

Freezing point, influence of

pressure - 136

French Academy of Science - 97,

115, 210

Fresnel, A. J. - 19, 20, 54, 119,

122, 137

Fry, P. W. - - 173

Falconry - 258

Faraday, Michael :

Electro -magnetic induc-
tion, discovery of 20, 31,
37,43, 191, 198,213
Inductive capacities - 82
Optical glass - - 205
Farey - - 319

Fibrinogen - 299

Fire-damp - - 115

Fitton, W. H. - - 316

Fitzgerald, G. F. - 137, 138
Fitzroy, Capt. - - 271

Fizeau - - 132

Flamsteed, J. - 67

Fleming, A. - - 257

Flora :

Australiensis - - 246

Colonial - - 247

of Hong Kong - - 246

Indica - 248

Flower, Sir William - 267, 283

Fluorescence - - 124

Fluxions - - 35, 53, 117

Forbes, E. - - 289, 317

Forbes, J. D. - 132, 136, 311

Fossils - - - 309, 312

Foster, Sir M. - 250, 300, 304

on F. M. Balfour - 285

Galileo -

Galen

Gadow, H.

Galitzin, Prince

Galle

Galton, Sir F. -

Galvani, L.

Galvanism

Gamble, J. C.

5,8,9
216, 219

- 284

- 179

- 127
277, 286

- 106

- 112
194-197

Gas, illuminating, first used - 105
Gay-Lussac - - 37, 115
Gassylvestre - - 66

Gascoigne, W. - 57, 94

Gases :

Diffusion of 145

Kinetic theory of - 33
Liquefaction of 139, 212, 213
Transpiration of - - 145
Viscosity of - 34

Gaskell, W. H. 301, 302, 303, 304
Gassiot, J. P. - - 162, 209
Geikie, Sir A. - - - 318
Geikie, J. - 318

Geissler tubes - - 162

Gellibrand, H. - - 58

Geodetical Survey - - 207
Geological Society - - 212
Geological survey, Govern-
ment - - 315
Geology - - 308-319

326

Index

PAGE

Geometry, analytical - - 49
Geo -physics - - 133

Gerard, J. - 229, 231

Gesner, C. 220, 256, 257, 258

Gilbert, W. - - 3

Gill, Sir D. 166-8

Glaciers - - - 133, 136
Glaisher, J. W. L. - - 141
Glaisher, James - - 176

Glass:

Optical - 81, 168, 205
Glazebrook, Sir R. - - 210
Glisson, F. - 297

Glover, J. - 198

Godman, F. D. - - 293

Goodsir, H. - - 289

Goodyear, C. - - - 190
Gordon, R. M. - - - 173
Gossage, W. - - 197

Gosse, P. H. - - 290

Gout - - 297

Graebe - - 200

Graham, G. - 95, 97

Graham, T. 68, 144, 145, 202, 254
Granite, igneous origin - 310
Gravitation 10, 11, 53, 64, 86
Gray, Stephen - 78

Greaves, J. - - - 49
Green, G. ... 121

Greenwich Observatory - 57,
165, 207, 208
Greenwich time, automatic

transmission of - - 166
Gregory, family of - 52

Gregory, D. - 52, 98

Gregory, J. - 52

Gresham, Sir T. 47

Gresham College - 46, 47, 203
Greville, R. K. - - - 254
Grew, N. - - - 232, 234
Grove, W., Lord Justice - 163
Guericke's air-pump - 75

Guillim, J. - - - 221
Gunter .... 94

Hadley, J.
Haime

- 95

- 317

PAGE

Hales, S. - 204, 236, 255,

288, 298

Hall, C. M. - 99

Halley, E. - 58-60, 92

Halley's comet - 59

Hamilton, Sir W. R. - - 136
Hamilton's principle - - 136
Hancock, T. - - 190

Harcourt, V. - - 141

Barker, A. - 311

Harris, Sir Snow - 205

Harrison, J., chronometer 69, 96
Hartley, W. - 160

Harvey, W. - 219, 223, 294
Haughton, T. - - 137

Havers, C. - - - 298
Hauksbee, F. - 77, 78

Heart :

Structure of - 297, 303
Cardiac -plethysmograph
and cardio -myo graph,
invented - - 306

Heat:

Conductivity of - - 133
Equivalent of 26

Latent - 66, 86

Mechanical theory of - 25,
29, 108, 135

Polarization of - - 133

Radiation of - 76, 93,

131, 152, 158

Radiations - - 93

Specific, method of cool-
ing- - 131
Heliometer - - - 168
Helium - - 171, 181, 184
Liquefaction of - - 214
Hemming, J. - - 198
Henley, W. ... 80
Henry, T.- - - 148
Henry, W. - 148
Henslow, J. - - 253, 270
Heraclitus - 8
Heraldry - - 221
Herapath - - 33
Herbert of Cherbury, Lord

220, 225

Herbert, J. - 267, 274

Heredity, Mendelian theory 278

Index

327

PAGE

Horschel, Sir John - 118,124,
156, 166

Hyposulphite, in photo-
graphy - - 173
Coloured flames - - 153
Optical glass manufac-
ture - - 205
Herschel, Sir W. 88, 90, 126, 169
Discovery of Uranus - 91
Finger-prints - - 286
Infra-red rays - 93
Star drifts 93
Hicks, H. - 313
Hieroglyphics, Egyptian - 37
Hill, E. - - 254
Hippocrates - - 216, 297
" History of Fishes " - - 259
" Historie of Foure -Footed
Beastes " and " Historie
of Serpents " - 220, 258
" History of Insects " - 259
Hofmann, A. W. 194, 199, 201
Holland, P. - - 217
Homfray, D. - - 314
Hooke, R. - 17, 55, 77, 259
Anchor escapement - 95
Mechanical theory of

heat

Pepys on -

Waller on -

Hooker, Sir J. D

Hooker, Sir W. J.
Hope, J. C.
Hopkinson, J. -
Hornblower, J. 0.
Horrocks, J.
Horse -power, first

term

Horticultural Society -
Howard, Henry (Duke

Norfolk)
Howard, L.
Hudson, Dr.
Hughes, D.
Huggins, Sir W.
Humboldt
Hume, D.
Hunter, J.

- 108

- 227

- 259

- 247, 255,

279, 289

- 246

- 130, 131

- 193

- 105
S, 89, 95, 207
use of

of

104
245

- 210

- 176

- 290

- 190

- 171

- 244

- 65
263-5

PAGE

Hunter, W. - - 263

Huntsman, Benjamin - 187

Hussey, J. T. - - 126

Hutton, C. - 64, 70, 86, 87

Hutton, James - 70, 245, 310, 316
Huxley, T. H. - 249, 279, 282,
291, 301

on Darwin - - 267, 278

on Owen - 265

Huygens, C. - 9, 17, 51, 95,

210, 211

Hydraulic press - 105

Hydrogen, generated by

electrolysis - - - 107

Solidified - - 214

Hydrogenium - - - 145

Hysteresis - 193

Illuminating gas, first used - 105
Infra-red rays, Herschel - 93
Ingenhouse, Dr. - - 81

Inoculation - - 204, 306
Instruments, scientific, con-
struction of - - 94, 95
Interference of light -
Integral calculus - 53, 117
Inverse square, law of, in
gravitation - - 10, 53
In electricity - 69, 81
Iodine, discovery of - - 115
lonization - - - 146
Ireland, Royal Society of,

Dublin -

Irish Academy of Sciences - 211

Irish universities, botany at 254

Physical science at - 137

Irvine - - - - 67

Jack,W. -
Jail fever -
Janssen -

- 151

- 204

- 171

328

Index

Jeffreys, G.
Jellett, J. H.
Jenkin, F.
Jenner, E.
Jenyns, L.
Joly, C. J.
John of Trevisa
Johnson, Thomas

PAGE

- 289

- 137

- 292
264, 306

- 271
137, 174

- 217

- 231

Joule, J. P. 23, 28, 31, 40, 191
Equivalent of heat - 26
Velocity of molecules - 33

Journal of Physiology - 302

Kanthack, A. - .,, - 306

Kater, Capt. H. . 174

Kater's pendulum - - 175

Kelland, P. - _ 234

Kelvin, Lord (W. Thomson) 42,

123, 127, 134, 136

Appreciation of Joule - 41

Economics of dynamo

engine - - 192
Electric replenisher - 80
Second law of thermo-
dynamics - 28
Submarine cables - 189
Kennett, B. - 173
Kepler - - 8, 10, 53
Hew Observatory - - 209
King, J. - - 173
King's College, London,

foundation - - - 143

Kircher - - - 124

Kirchhoff - - - 157

Kite, meteorological - - 176

Klingenstjerna - - - 93

Knight, T. A. - - 238

Krypton, discovery of - 181

Lacteal vessels in birds, dis-
covery of 299
Langley, J. N. - - 299, 301
Lankester, Sir E. R. . 250, 278,
287, 288

PAGE

Laplace - - 20, 123

Larmor, Sir J. - - - 182
Lassell, W. - - 169

Latent heat, see under Heat.
Laughing gas - - 110

Lavoisier - - 14, 55

Leblanc - 194, 196, 197, 198
Lee, S. H. - 301

Leeds University - - 160
Legh, G. - - 221

Le Gray, G. - - 173

Leibnitz - - - - 117
Length and weight stand-
ards, reconstruction - 130
Leslie, J. - - 131

Leverrier, U. J. J. - 126, 127
Lexell - 91

" Liber de Proprietatibus

Rerum " _ 217

Liebermann - - 200

Life statistics - : - 60

Liebig, J. . - 199, 202

Light :

Aberration of - 62, 70
Conical refraction - 137
Corpuscular theory of - 17
Electro -magnetic theory

of - - 32

Fluorescence - - 125
Infra-red rays - - 93
Polarization - 19, 147
Refraction - 53, 81, 98, 121
Spectroscopy - 152-159
Wave theory 17, 18, 55, 56,
122, 123

Lighthouse illumination - 193
Lightning conductors - - 205
Lindley, J. - 245, 255, 316
Lindsay, Lord - - 167

Linnaeus - - 233, 239

Linnsean Society - 212

Lippmann, G. - - 173

Liquefaction of gases - 139, 213
Lister, Lord - - 306

Liveing, G. D. - - 159

Load-stone, origin of word - 4
Lockyer, Sir J. N. 159, 171, 181
Logarithms - - - 7, 48
Lloyd, H.- - - 137

Index

329

PAGE

Lodge, Sir O. - -214

Locomotive, first - 104

Lower, Richard - -297

London, University of, foun-
dation - - 143
London - - 245
Lubrication, theory of - 151
Lumiere et Fils, colour

photography - - 174

Lyell, Sir C. 273, 279, 311, 317
Lymphatic vessels in birds,

discovery - - 299

Lyte, H. - - 230

Lyons, I. - - • - 241

McCartney, J. - - - 264
McCoy - - - 314, 317
McCullagh, J. - - 122, 137
Maclaurin, C. - 56

Macleod, H. - - 199

Maddox, R. L. - - - 173
Magnetism, terrestrial 4, 120,

152, 209

Declination - 3

Diurnal variation - 95

Inclination - - 4

Secular variation - 58

Malpighi - - - - 255

Malthus, T. R. - - 274

Manchester University 148, 160

Mantell, G. A. - - 316

Marine biological stations - 293

Marine zones - - 289

Martin, N. - 250, 301

Martyn, T. 252

Maskelyne, N. - - 63, 86, 87

Mason College - - 161

Matthew, P. - - 274

Matter, atomic theory - 15

Electron theory - - 182

Maxwell, J. Clerk 8, 43, 44, 200

Electro -magnetic theory

of light 32

Kinetic Theory of G ases 34

On Cavendish* - 82

on second law of ther-

mo-dynamics - 30

PAGE

Mayow, J. 55, 225, 296

Medicine and surgery - - 262,

263, 306

Meldola, R. - - 201

Melville, T. - - 152

Mendel, G. - 277, 278

Mendelism - 280

Mercator's projection - - 48
Meteorology 147, 176, 208, 209
Michell, J. - 86, 87, 88

" Micrographia " - 55,260
Micrometer, invention of - 94
Double image - - 97
Microphone - - 191

Miers, Sir H. - - 181

Milky way - - 92

Miller, H. - 315

Miller, W. A. - - 164

Miller, W. H. - - 129

Milne, J. - - 178, 214

Milton, J. - - 220

Miner's lamp, invention of - 116
Moffett, T. - 219

Molyneux family - 89

Molyneux, Samuel - 61, 89, 90
Mond, L. - - . - 198

Moore, C. - - 316

Morse code - - 189

Morison, R. 232, 233, 234, 251
Moseley, H. N. - - 291

Moseley, H. - - 184, 185
Motion, laws of - 9

Mulgrave, Lord - - 288

Multiple proportion, law of- 16
Murchison, Sir R. - - 314
Murdock, W. - - 105

Murray, J. - 291

Muscle, striated - 300

Muspratt, J. 195, 196, 197, 198

Napier, John, of Merchiston 6
Nasmyth, James - 169

National Physical Labora-
tory - - 209, 214
Natural selection - 272, 274

330

Index

PAGE

Nautical Almanac - 37, 63

Nautilus, Pearly - 265

Navigation, influence on

science - - 47, 63, 96

Nebulae - - 169, 170

Spectrum of - 172

Neon, discovery of - - 181

Neptune, discovery of 125-7

Neumann, F. - - 122

Newall, R. - 172, 189

Newcombe, S. - - 125, 126

Newcomen, T. - - 101

Newton, Sir Isaac - - 33,
34, 52, 76, 211

Fluxions - 35, 53

Gravitation 10, 11

Laws of motion - >- - jfc

Light - 53-56, 98

Tides- - .-; - 177

Nicholson, E. C. -> . - 201

Nicholson, W. - -- 80, 107

" Nicholson's blue " - - 201

Nicholson's Journal - 107,111

Niepce, J. N. - - 173

Nitrogen, isolation of - - 68

Nitrous oxide - - 111

Noble, William - - 50

Norman, Robert - 3

North- West Passage - - 175

Nutation, of earth's axis - 63

Odling, W. - - 141

Ohm - 82, 114

Ohm's law - 134, 147

Oncometer, renal - - 306
Onnes, Kamerlingh - 140

Optical instruments - 90, 97, 98,
169, 170, 172
Optics, physiological - - 299

(See also under Light.)
Orchidese - - - 244, 247
Origin of Species - 248, 273

Reception of - 279, 286
" Ornithology," Willughby's 259

Osmosis, G.
Otley, J. -
Oughtred, W. -
Owen, Sir R.
Owens, John
Owens College -

PAGE

- 145

- 314

- 94

- 265-7 y 317

- 148

- 148

Palladium, discovery of - 145

Papin, D. - 100, 101

Parallax, stellar - 61, 90, 168

Parry, E. - 175

Parsons, Sir C. - - 187

Pascal - 76
Patents examined by Royal

Society - - 204

Paxton, Sir J. - - 245

Peacock, G. - - 118,119

Pearson, K. - - 286, 287
Pendulum :

Anchor escapement - 95

" Gridiron " - 96

Rater's • - 175

Pennant, Thomas - - 262

Penny, T. - - 220

Pentane lamp - 141

Pepys, S. - - 222, 226

Perkin, W. - 199-201
Petrograd Academy - 209,211

Petrography - - 164

Phillips, J. - 315, 316

" Phlogiston " - 14, 84
Photography :

Astronomical - 168-170

Colour 173-4

History - - 166, 172-4
Physic Garden :

Chelsea - - 241

Dublin - - 254

Lambeth - - 261

" Physiologus " - - 216

Physiology - 294-307

of plants - 237, 249

Phy to -geography - - 255

Phytophthera infestans - 250

Picard - 10, 11

Pigot, T. - 50

Index

331

PAGE
Plants :

Binomial nomenclature
of - - 239

Classification of, natural
system - - 245

Physiology of - 237, 249
Playfair, J. - 70, 131, 310

Playfair, L. - - 202

Pliny - 216, 217, 257

" Poikilitic " - - 316

Poisson - - 20

Polarization of heat - - 133
Polarization of light - 19, 147
Pond, J. - - 60

Potassium, discovery of - 113
Potential - - - - 123
Poynting, John 152, 160, 161

Powell, J. Baden 121, 140, 141
Prestwich, Sir J. - 317, 319
Prevost - - 156

Priestley, J. - - 14, 84, 238
Pringle, Sir J. - - 204

Pritchard, C., astronomical

research - 141

Pritchard, M. - - 274

" Principia " - 10

Professorships :

Dates of foundation - 46
Proteaceae - 244

Prout, W. - 181

Pullen, Capt. - - 291

Pump, air - - 75, 181

Turbine - - 151

Pythagoras 8

Quaternions

137

Radiation of heat, see under

Heat.

Radio-activity - - 183

Radiometer - 151, 180, 181
Radium, discovery of 183, 184
Rainbow, explanation - 120

PAGE

Ramsay, Sir W. - 181

Ramsden, J. - 81, 97

" Ramsden's eyepiece " - 97
Rankine, W. J. M. - - 134
Ray, J. - 231, 233, 259, 261
Rayleigh, Lord - 122, 159, 164
Discovery of argon - 181
First step in colour photo-
graphy - - 173
Refraction, see under Light.
Renal oncometer - - 306
Respiration • ••' "V''. - 296
Reinold, A. - - - 160
Reynolds, O. • - 23, 26, 150
Rhodes, Cecil - - 168
Rhodium, discovery of 145
Rickets - - 297
Roberts, I. - ^ - 170
Robison, J. - - 65, 68, 81
Rocks, arrangement in layers 309
Roebuck, J. - - 194
Roemer, O. 62
Roentgen, W. C. - 183
Romanes, G. J. - - 285
Ronalds, SirF. - 187, 188, 209
Roscoe, H. E. - - 149, 150
Ross, Sir James - 288, 289
Ross, Sir John - - 289
Rosse, Lord - - 169
Routh, E. J. - - 127
Roy,Maj.-Gen. - - - 207
Roy, C. S. - 306
Royal Astronomical Society

208, 212
Royal College of Chemistry

194, 199

Royal College of Physicians 265,
294, 295

Royal College of Surgeons 265, 283
Royal Institution, founda-
tion - - 109, 213-4
Royal Society - 51,77,203-213
Royal Society of Arts - 211
Royal Society of Dublin - 211
Royal Society of Edinburgh 211
Rubber, commercial produc-
tion of - - 190
Rucker, A. - 160
Rumford, Count 27, 107, 108, 213

332

Index

PAGE

Russian Academy communi-
cations to Royal Society -

209, 211

Rutherford, D. - 68

Rutherford, Sir E. - - 183

Sabine, Gen. Sir E. 175, 207, 209
Safety lamp - - 116

Safety valve, invention of - 101
Salter, J. W. - 313, 314, 317
Salmon, G. - 137

Salvin, O. - 293

Sanderson, Sir B. - - 304
Sandstone :

Red, new - '* ' - 316
Old - - 315

Sap, ascent of - - 232,238
Saron - - 91

Saturn's rings - - 128

Savery, Thomas - 100, 104
Scheele - - 172

Schehallien experiment 64, 86, 87
Scottish universities, scienti-
fic activity - .,» 64, 130
Schunck, Edward - - 163
Sea, exploration of - " - 288
Sedgwick, A., sen. 271, 310, 314
Sedgwick, A., jun. - - 285
"Seiches" - 134

Seismology Wg 133, 178, 214
Semaphore - 188

Sextant, invention of - - 95
Sexuality of plants . - 235, 236
Sharpey, W. - - 304

Sherard, W. - - - 251
Shore, L. - - 303

Sibthorp, J. J. - * 251

Siemens, W. - '0%£ - 192
Silurian rocks - - 314

Simpson, Thomas 56

Simpson, Sir J. Y. - 305

Slide rule, invention of - 94
Sloane, Sir H. - - 240

Smith, Adam - 65, 68

Smith, H. J. - 140-3

Smith, Sir J. E. - 232, 240

Smith, L. - 306

PAGE

Smith, Robert - 71, 90

Smith, R. A. - 149

Smith, W. - - 309, 318

Snell - - 53

Sodium, discovery of - - 114
Soddy, F. - 183

Solander, D. - - 241, 242
Solar system, motion in

space - - 93

Sorby, H. C. - - 163, 312
Sound - - 50, 71, 77

Sowerby, J. de C. - - 317
Solvay, E. - 194, 198

Spottiswoode, W. - - 163
Spectroscopy - - 153-159
Applied to Astronomy -

171-172

Spirit level - 56

Stanhope, Lord - 212

Star catalogue - - 57, 162
Star-drifts - 93

Stars, double - -88, 92

Steel, scientific production - 187
Steam engine :

Invention of - 99-105
Propulsion of ships - 101
Turbine - - 187

Stewart, Balfour 150, 152, 209
Theory of exchanges - 158
Stewart, M. - - 56

Stereoscope, invention of - 148
Stokes, G. G. - 20, 32, 123-5
Radiation and absorp-
tion - 157, 158
Stoney, G. J. - - 139, 182
Strontium, discovery of 130
Sturgeon, W. - 24, 148, 191
Survey - - 174, 207
Sutherland, J. - - 253
Swan,W. - - 154
Sydenham, T. - - 296
" Sylva " - - 225
Sylvester, J. J. - - 128, 141
Symmer, R. - 79

Tait, P. G.
Talbot, F.
Taylor, B.

127, 133, 139
- 153, 173

- 77

Index

333

PAGE

Tawney, E. B. - - 313

Teall, J. J. H. - - 311

Telegraphy :

Invention of - 187

Submarine- - 189

Wireless - - 33

Telescope, reflecting 52, 54, 169,

170

Refracting- 54, 172

Temperature, critical - 140

Tennant, C. - - 195

Terrestrial magnetism, see

under Magnetism.
Thales - 8

Thallium - - - 159

" Theater of Insects " - 220
Theobaldus - - 217

Thermodynamics :

First law - - 23

Second law of - 26, 28
Thermometer - - 83

Self-registering - - 288
Thin films, thickness mea-
sured - - 160
Thiselton-Dyer, Sir W. - 249,
250, 272
Thompson, B., see Rumford,

Count.

Thompson, -Vaughan - - 292
Thomson, James - 135, 136
Thomson, Sir Joseph - 152, 182
Thomson,William, see Kelvin,

Lord.

Thomson, Wyville - 289, 291
Thorpe, Sir E. - - 109, 160
Threlkeld, Caleb - - 254
Tides - 177, 178

Time signals - - - 166
Topsell, E. - 220, 257

Torpedo - - 83

Torsion balance, invention

of 86, 87

Townley, R. - - 75, 95
Tradescant, John, the elder 260
Tradescant, John, the younger 261
Transit of Venus, see under

Venus.

Transpiration of gases - 145
Trevithick, R. - - 104, 105

PAGE

Trinity College, Dublin 137-139

Turbine :

Engine - - 187

Pumps - - - 151

Turner, W. :

Botany - - 229, 230
Zoology ... 256

Tyndall, J. - 88, 213

Type printing machine - 191

Ultra-violet rays - 124

Uniformitarian theory - 311
University College, founda-
tion of - - 143-146
Uranus, discovery of - - 91

Vaccines, first used - - 306
Vacuum tubes, invention of 162
" Valency " - 148

Vanadium - 150

Venus, transit of - 52, 63, 88,
167, 207, 209

Vernier - - 56

Vertebrate, origin of, re-
search - - 303
Vesalius - - - 219
Vines, S. H. - - 250
Viscosity of gases - - 34
Vives - - 218, 221
Volta, A. - - 80, 106
Voltaic arc - 114
Vulcanite, invention of 190
Vulcanization - - 190

Wallace, A. R.
Wallich, Dr.
Wallis, John
Waltire -
Ward, Joshua
Ward, M. -

273, 281
291, 292

- 50

- 85

- 194
250, 253

334

Index

PAGE

Water:

Composition of - 85

Compressibility of - 80
Electrolytic decomposi-
tion of - - 107
Maximum density of - 130
Waterston, J. - - 164
Watson, W. - - 81
Watt, J. - - 69, 70, 101-104
Composition of water - 85
Wedgwood, T. - - 172
Weights and measures, stan-
dards - -49,130,207,208
" Weismannism " - - 280
Weldon, Walter - 198
Weldon, W. R. F. - 277, 286
Wells, W. C. - - 176
Wernerian theory of geology

310, 311

Westbrook, W. - - 306

Wheatstone, Sir C. - 147, 148

Stereoscope invented
Spectrum analysis
Telegraphy -

" Wheatstone bridge "

Wheler, G.

Whewell, W. -

Wilcke, J. K. -

Wilde, Dr. Henry

Williams, Dr. -

Williamson, A. M.

Williamson, W. C.

Willis, T. -

Willughby, F. -

148
154
188
147
78
119, 223, 271

59, 192

- 314

- 146
- 305, 316

- 297
232, 259, 261

PAGE

Wilson, A. - - - 176

Witham - - 316

Wollaston, F. J. H. - - 86
Wollaston, W. H. :

Chemical discoveries - 145

Spectrum analysis 153, 155

Photography - - 172

Woodhouse, R. - 117

Wooldridge - - 305

Woolf, A. - 105

Worcester, Marquis of, Edw.

Somerset - - 99, 100

Wortley, Col. Stuart - - 173

Wotton, E. - - 220, 257

Wren, Sir C. - - 51, 297

Wright, Edward - - 48

Wright, E. P. - - - 316

Xenon, discovery of - - 181

X-ray, discovery of - - 183

See also Radio-activity.

Young, T. - 18, 37, 119, 153, 213
Brougham's criticism of 20
Explanation of super-
numerary rainbows - 120
Physiological optics 128, 299

Zoology -

256-293

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