Full text of "Science progress in the twentieth century : a quarterly journal of scientific work & thought"

■ (]■ * f j M - i j 1 1 ■ 1 J 1 T ( '
■It f » » it li* i is3w is kit j

liliSIIl

l'i\}y M

mluii 1

SCIENCE PROGRESS

IN THE TWENTIETH CENTURY

A QUARTERLY JOURNAL OF

SCIENTIFIC WORK

& THOUGHT

EDITOR

SIR RONALD ROSS, K.C.B., F.R.S., N.L.,
D.Sc, LL.D., M.D., F.R.C.S.

VOL. IX
1914- -1915

LONDON
JOHN MURRAY, ALBEMARLE STREET, W.

1915

PRINTED BY

1IAZELL, WATSON AND VTNEY, LD.

LONDON AND AYLESBURY,

ENGLAND.

INDEX TO VOL. IX (1914— 1915)

I. ARTICLES AND NOTES

PAGE

Apes, and their Bearing upon the Antiquity of the Hominidae, The Extinct.

A. G. Thacker 281

Atom, The Constitution of ......... 169

Atomic Theory, Some Aspects of. F. Soddy 573

Birth-Time of the World, The. J. Joly 37

British Science Guild, The .......... 165

British Science Guild, Action of the ........ 353

British Science Guild and the Fight for Science, The .... 663

Bristol University . . . . . 513

Capillary Constants and their Measurement. A. Ferguson . . . 428
College of Surgeons of England, The Society of the Members of the

Royal. S. C. Lawrence . . .517

Colour Vision and Colour- Vision Theories, Including the Theory of Vision.

F. W. Edridge-Green 471

Coloured Thinking and Allied Conditions. D. F. Harris . . . .135
Conductors at very Low Temperatures, Electrical Properties of. F. Hynd-

man 586

Correspondence, " Elementary Logic." A. Sidgwick 676

„ "Evolution of Co-operation." H. Reinheimer . . .521

„ H. S. Shelton . 355

„ Party Politics and Scientific Representation. A. J. Gray 676

Cotton, Science and the Supply of Fine. W. L. Balls .... 290

Cranks, Our Unspeakable 670

Curves of Life : A Criticism, The. H. G. Plimmer 396

Dentistry, Ancient and Modern. C. E Wallis 500

Dyeing, Theories of. E. A. Fisher 310

Earthquakes, The Prevision of. C. Davison 639

Educational Science . 510

German Lie, The Quality of the 666

Germ-Cell Cycle in Animals, Some Recent Additions to our Knowledge

of the. R. W. Hegner 270

Igneous Rock Classification, A Review of. G. W. Tyrrell ... 60

Institut fur Schiffs- und Tropenkrankheiten 166

Irrationalism 1

iii

INDEX TO VOL. IX

Kitasato Institute for Infectious Diseases, Tokyo, The

Logic, A Reply to some Charges Against. Miss L. S. Stebbing
Logic, The Value of ........

Logical Impossibilities, Some. C. A. Mercier ....

PAGE
6 75

406
I67
209

Manufactures, as Illustrated by the History of the Alum Trade, The

International Struggle for. Rhys Jenkins ....
Mars, The Temperature of. P. H. Ling

Militarism and Party Politics

Municipal Insanitation .

Organism a Thermodynamic Mechanism, Is the? J. Johnstone
Ozone in the Upper Atmosphere, and its Influence on the Optical
Properties of the Sky, The Formation of. J. N. Pring

Pacificist, A Converted

Palaeontology in 1914, Vertebrate. R. Lydekker

Photographic and Mechanical Processes in the Reproduction of Illustra

tions. R. Steele ........

Pigments, The Anthocyan. A. E. Everest ....

Plant Chimasras. M. Skene

Plant Oxidases, Some Recent Work on. W. R. G. Atkinson

Pond Life in the Spring, A Probable Causative Factor in the Awakenin

of. A. H. Drew

Radium, The Terrestrial Distribution of. A. Holmes
Relativity, The Principle of .

Research, The Professors and the Organisation of
Respiration, The Bio-chemistry of. H. M. Vernon

Science and the State : A Programme ....

Science, War, and Agriculture ......

Sea Fisheries, Scientific Research and the. J. T. Jenkins
Sea-Salt and Geologic Time. H. S. Shelton
Smoke Abatement : Notes on the Progress of the Movement to Secure a
Cleaner and Purer Atmosphere. J. B. C. Kershaw

Thomas Young Oration, The ....

Tornadoes and Tall Buildings. J. Huneker

Undergraduates and the Betterment of Science .
Union of Scientific Workers, Proposed

Variation, The Cause of. A. D. Wilde

Vitalism, A Survey of the Problem of. Hugh Elliot

Vitamines. H. W. Bywaters ....

War, Evolution and. G. Taylor- Loban

War, The Fools' .

488

385

172

646

448

669
613

153
597
127
1 12

352
672

197
671
IO5

674
347

354
164

85
4ij
22s

663

INDEX TO VOL. IX

II. AUTHORS OF ARTICLES

Atkins, W. R. G. .

Balls, W. Lawrence
Bywaters, H. W. .

Davison, Charles .
Drew, A. H. .

Edridge-Green, F. W.
Elliot, Hugh .
Everest, Arthur E.

Ferguson, Allan
Fisher, E. A.

Harris, David Fraser
Hegner, Robert W.
Holmes, Arthur
Huneker, James
Hyndman, Francis

Jenkins, J. T.
Jenkins, Rhys
Johnstone, James

Joly, J. . .

Kershaw, J. B. C.

Ling, P. H. .
Lydekker, R .

Mercier, Charles A

Plimmer, H. G.
Pring, J. N. .

Shelton, H. S.
Skene, MacGregoi
Soddy, Frederick
Stebbing, L. S.
Steele, R.

Thacker, A. G.
Tyrrell, G. W.

Vernon, H. M.

Wallis, C E.
Wilde, A. D.

PAGE

112

290

225

639
96

471
413

597

428
310

135
270

347
586

105

488

646

7
613

209

396
448

55i 355
127

573
406

28l
60

25I

500
85

INDEX TO VOL. IX

III. AUTHORS OF BOOKS REVIEWED

PAGE

American Medical Association, " Report of the Committee on Standards

and Methods of Examining the Colour- Vision " . . . . . 723

Armstrong, W. E. M., "I.K. Therapy"

Baker, R. T, " Cabinet Timbers of Australia " .

Balch, H. E., " Wookey Hole"

Barger, G., "The Simpler Natural Bases"

Bashford, E. F., and others, " Annual Report of the Imperial Cancer

search Fund "..........

Beyschlag, F., " The Deposits of the Useful Minerals and Rocks "
Biedl, A., "The Internal Secretory Organs" ....

Bolton, J. S., "The Brain in Health and Disease" .
Boulenger, E. G., " Reptiles and Batrachians " .
Boulenger, G. A., " The Snakes of Europe "

„ „ and C. L., "Animal Life by the Sea-Shore"

Branford, V., "Interpretations and Forecasts" ....
Broad, C. D., " Perception, Physics, and Reality "...
Burkhardt, H., " Theory of Functions of a Complex Variable " .

Carson, G. St. L., and W. E. Smith. "Plane Geometry"
Chamberlain, H. S., " Immanuel Kant ".....

Chapman, F., " Australian Fossils "

Chisholm, J. Don and J., " Modern Methods of Water Purification "
Clarke, H. T., "An Introduction to the Study of Organic Chemistry"

Clodd, E., " The Childhood of the World "

Cook, M. T., "The Diseases of Tropical Plants" ....

Copeland, E. B., " The Coco-Nut "

Crabtree, H., " An Elementary Treatment of the Theory of Spinning Top

and Gyroscopic Motion "

Crawfurd, R., " Plague and Pestilence in Literature and Art " .

Croce, B., " Philosophy of the Practical "

Crookes, Sir W., "An Acquired Radio-Activity" ....

n „ „ " On the Spectrum of Elementary Silicon " .

Davies, G. M., " Geological Excursions round London " .

Dawson, W. D., "The Yearbook of the Universities of the Empire, 1914

Desch, C. H., " Intermetallic Compounds"

Dickson, L. E., "Elementary Theory of Equations" ....
Dixon, H. H., "Transpiration and the Ascent of Sap in Plants"
Dunstan, A. E., and F. B. Thole, " The Viscosity of Liquids "

568

186

55o
361

562
707
376

565
716
184

372

529

357
533

697

523
183
380

359
182

187

722

540

529
188

703
703

363
382
176
689
719
176

Eddington, A. S., " Stellar Movements and the Structure of the Universe" 541
Elderton, E. M., "Report on the English Birthrate" . . . .726

Elliott, C, " Models to Illustrate the Foundations of Mathematics " . 694

Fantham, H. B., and Anne Porter, " Some Minute Animal Parasites " . 376

Fischer, Gustav, " Lehrbuch der Anthropologic in Systematischer Darstellung" 363

Fletcher, T. B., "Some South Indian Insects" 7*7

Folsom, J. W., "Entomology" 560

INDEX TO VOL. IX

Ford, W. B., and C. Ammerman, "Plane and Solid Geometry" . . 536
Friend, J. N., H. F. V. Little, W. E. S. Turner, and H. V. A. Briscoe,

"A Text-book of Inorganic Chemistry" 705

Fritsch, F. E., "An Introduction to the Study of Plants".

Geikie, J., "The Antiquity of Man in Europe"

Gower, A. R., " A Text-book of Experimental Metallurgy and Assaying "
Gowland, W., " The Metallurgy of the Non-Ferrous Metals "...
Graham-Smith, G. S., "Flies in Relation to Disease" .
Gray, F. W., " A Manual of Practical Physical Chemistry "...

Gruner, O. C, " The Biology of the Blood-Cells "

Grunwald, J., "The Raw Materials for the Enamel Industry".

Haas, P., and T. G. Hill, "An Introduction to the Chemistry of Plant
Products "

Haberlandt, G., " Physiological Plant Anatomy "...

Hale, A. ]., "The Synthetic Use of Metals in Organic Chemistry"

Hall, C. J. J. van, "Cocoa"

Hamaker, J. I., " The Principles of Biology " . . . .

Heatherley, F., "The Peregrine Falcon at the Eyrie"

Hegner, R. W., "The Germ-Cell Cycle in Animals" .

Hehir, P., "Hygiene and Diseases of India" ....

Henson, G. E., "Malaria"

Hewitt, C. G., "The House-Fly"

Hiorns, A. H., " Principles of Metallurgy "

Houard, C, " Les Zoocecidees des Plantes d'Europe et du Bassin
Mediterranee" .........

Houston, A. C, " Studies in Water Supply "

Hughes, A. L., " Photo-Electricity "

Jones, W., " Nucleic Acids "

de la

Kaye, G. W. C, "X-Rays"

Kellicott, W. E., "A Text-book of General Embryology" .

„ „ " Outlines of Chordate Development "

Kingscott, P. C. R., and R. S. G. Knight, " Methods of Quantitative

Organic Analysis "..........

Knibbs, C. H., "Federal Handbook of the Commonwealth of Australia"

558

180
180

548
716
704
691

548

178

377
177
721

37o
562
712
192
190
718
362

185
380
544

360

358
7i4
7M

547
569

Lamarck, J. B., and H. Elliot, "Zoological Philosophy"

Levick, G. Murray, " Antarctic Penguins " .

Levy, S. T., " The Rare Earths " ....

Lock, R. H. "Rubber and Rubber Planting" .

Loeb, J., "Artificial Parthenogenesis and Fertilisation"

Low, P. R., " Our Common Sea-birds "...

Lyman, T., " The Spectroscopy of the Extreme Ultra-Violet " .

MacBride, E. W., " Text-book of Embryology " .
Macmunn, C. A., " Spectrum Analysis ".....
Marsh, H. W., "Constructive Text-book of Practical Mathematics"
Masson, F., " Robert Boyle "

553, 556
374
709

187

367

373
699

711

546

693
527

viii INDEX TO VOL. IX

Mathews, G. B., " Projective Geometry "

Merrier, C A., "A Text-book of Insanity 1 '

Minot, C. S., " Modern Problems of Biology "

Morgan, A. de, " Essays on the Life and Work of Newton "

Morgan, T. H., "Heredity and Sex"

Moritz, R. E., " Memorabilia Mathematica "

Mott, F W., "Nature and Nurture in Mental Development" .
Mottram, J. C, "Controlled Natural Selection and Value Marking"
Muirhead, W. A., " Practical Tropical Sanitation "

Nernst, W., " The Theory of the Solid State "

Newstead, R., "The Roman Cemetery in the Infirmary Field, Chester'

Osier, W., " A Way of Life

Parkinson, S. T., "Impurities of Agricultural Seed" ....
Patton, W. S., and F. W. Cragg, "A Text-book of Medical Entomology'
Pierce, F. N., "The Genitalia of the British Noctuidae" .
„ „ " The Genitalia of the British Geometrida? "

Planck, M., "The Theory of Heat Radiation"

Poynting, J. H., and Sir J. Thomson, "A Text-book of Physics" .

Reinheimer, H., " Evolution by Co-operation ".....
Richardson, O. W., " The Electron Theory of Matter "...
Rivers, W. H. R-, " Kinship and Social Organisation "...

Tompkins, A. E., " Marine Engineering "......

Turner, J. A., "Sanitation in India" .......

Waddell, J., " Quantitative Analysis in Practice " . . . .

Williston, S. W., " Water Reptiles of the Past and Present " .
Willstatter, R., and A. Stoll, " Untersuchungen uber Chlorophyll Methoden
und Ergebnisse "..........

Wright, W. B., "The Quaternary Ice Age" ....

Ziwet, A., and L. A. Hopkins, "Analytic Geometry"

Zoretti, L.. "Lecons de Mathematiques Generates " ....

696
727

371
687

367

527
567
368
568

704
724

531

379
375
561
561
700
698

3 6 9
701

380

Scott, W. B., "A History of Land Mammals in the Western Hemisphere" 559

Sidgwick, A., " The Application of Logic "

„ „ "Elementary Logic" 532

Silberstein, L., " The Theory of Relativity " 542

Shand, A. F., " The Foundations of Character " 678

Sheppard, S. E., "Photochemistry" 178

Shimer, H. S., "An Introduction to the Study of Fossils" . . . 710

Smith, H. G., "Minerals and the Microscope" 549

Sommerville, D. M. J., "The Elements of Non-Euclidean Geometry" . 534

Stanley, R., "Text-book of Wireless Telegraphy" 545

Steeves, G. W., "Some Main Issues". A 531

Stewart, A. W., " Chemistry and its Borderland " 547

190
192

177
715

365
362

539

694

SCIENCE PROGRESS*

IRRATIONALISM

One of the first things which strike the man of science when
he studies natural objects of the same class, especially living
objects, is the great variation which exists amongst them.
Nature abhors not only the vacuum but the straight line ;
and if we arrange objects according to any single measurable
quality which they possess, we generally find that they group
themselves according to certain well-known laws : the majority
of them are nearly but not quite equal in respect to the given
quality, but, at one extremity of the curve, a few of the objects
are very deficient in it, and, at the other extremity, a few of
them greatly excel the rest. The study of such arrangements
has now become a new and valuable branch of science ; and we
know exactly what to expect when we discuss, let us say, the
tallness or the weight of men, or the frequency of blue eyes,
or of certain deformities, and so on. We have scarcely yet
attempted to apply the same analysis to certain high mental
qualities, such as capacity for reasoning ; but to judge from
analogy even these lofty possessions of man are likely to be
dominated by precisely the same law.

In an inarticulate manner, indeed, the world generally does
recognise the principle — men are said to be of average intel-
ligence, or of high intelligence, or are even called fools. But
the principle is frequently disregarded in affairs of great public
importance. Thus in philosophical discussions appeals are
sometimes made to the opinion of the majority of mankind,
which is thought to over-rule the opinions of exceptional
individuals; and also in politics, especially in Britain, the
suffrage is given regardless of intellectual ability, and the
verdict of the nation is cited as being sufficient to overwhelm
that of any individuals, however trained they may 'be in the
art of reasoning, or however learned they may be in the details
of the measure under consideration. Yet a study of nature will
i

1 SCIENCE PROGRESS

suggest to the man of science that such conclusions are not
always justifiable.

We are very apt to wander here into the thickets of dogma.
Men have become accustomed to consider themselves to be all
equally heirs of heaven. They like to maintain that their
faculty of reasoning is a part of the spirit which they all
possess ; and from this datum they assume that they can all
reason equally well. But if we analyse the strands of which
reasoning is woven we shall begin to doubt such a doctrine.
We perceive that all the other faculties of the mind are subject
to great variation in different individuals. Take the musical
faculty, for example : most men and women are able to enjoy
the pleasures of melody and harmony ; but some have " no ear
for music," while others are so eminently gifted with it that
they become Mozarts and Wagners. The same holds with
regard to the appreciation of poetry, painting, sculpture, and
architecture. Science itself is a remarkable case in point,
because, while some persons can scarcely endure even to
think of a scientific problem, and others become Newtons
and Kelvins, the mass of mankind can do no more than com-
prehend with difficulty what they are taught as to the great
laws discovered by people more gifted than themselves. Similar
variations are to be seen as regards the lower faculties of the
mind — the hand-and-eye faculty which gives us success in sports,
the dexterity necessary in many arts, the readiness of speech
required in Parliament and the law courts, and even the clever-
ness which certainly so often leads to success in life. Yet we
seem to think that we can all reason, if we choose, with equal
exactitude, and are very much hurt if others doubt our capacity
in this respect.

The extreme degrees of irrationalism constitute insanity;
and lower degrees are found in a large proportion of persons
who cannot be called insane, but are recognised as being
stupid — slow in apprehension and inaccurate in judgment. But
irrationalism covers more than insanity and stupidity. It is
frequently found in men and women of very quick appre-
hension and of very good judgment in many affairs — especially
in those which concern their every-day life. They are often
agreeable, good, well-instructed, accomplished, successful, and
even capable or distinguished ; and in their own business or
profession may excel better reasoners than themselves. But

IRRATIONALISM 3

their mind fails at once when it is applied to any proposition
outside the class of propositions with which they have been
accustomed to deal. Their capacity for reasoning has been
trained to a certain point by their education and by the
necessity of making a livelihood — but not to the further point
where it becomes as secure a guide as possible in all matters.
When called upon to judge in affairs which concern themselves
they are thoroughly capable ; but they lose balance at once
when they let go the rock of their own interests. In a moment
they become either inflexibles or cranks — they stand stock-still
or fall over. Such persons are certainly not insane, nor may
they even be called stupid. Their mental vision is clear enough
for a short distance from the soul-centre, but becomes out of
focus for a longer one.

The defect really springs from that well-known weak spot
in the intellectual machinery — want of apprehension of the fact
that we must really not generalise upon too small a sample ;
that our little garden-plot of experience is, really, not the whole
world. Starting from this point — judging classes from indi-
viduals, leaping from one single observation to another — we end
by becoming generally unable to distinguish probability from
certainty, and finally land in any quagmire of dogma which we
may happen to reach ; and there we stick. But of itself, this is
little worse than that which often happens, from hurry or mis-
fortune, to the best of minds. True irrationalism depends upon
graver faults — first, the intellectual hebetude which will not
trouble to study more than one or two samples ; and secondly,
the curious pride which strives to cover such laziness by the
pretence that no further study is necessary. Arrived at this,
the man becomes an incurable ; for in thought, as in life, pride
is the end of effort and the proof of its own falsity.

Take, for example, the case of scientific experiments on
animals. The careful and honest reasoner would not dream of
studying this particular case in isolation from the whole class
of cases in which trouble or pain is caused by the stronger to
the weaker. He sees that we are not angels in this world, but
are dominated by the laws of Nature. We cannot live without
jostling, nor move without treading on corns. Every man's and
every animal's existence means some deprivation to others. If
we warm our hands at a fire, we do so at the expense of the
gloomy subterranean labours of those who have obtained the

4 SCIENCE PROGRESS

coal for us. Our fur coats are torn from the bleeding backs of
poor creatures of the arctic by our fellow-men, who risk their
lives for us in the work. The building of our houses, the laying
of our water-pipes and drains, and the daily supply of our
food, depend upon forced labour — forced by natural laws — of
thousands of others, perhaps less happy than ourselves. Our
journeys are made luxurious by those who swink at roaring
furnaces, or toil all day in a thousand factories ; and our ban-
quets are won at the expense of untold miseries to other living
creatures. Our simple daily food implies an enormous butcher's
bill, which can be roughly computed if we remember that each
of the thousand millions of human beings in the world destroys
so many lives a week. Nor can the meekest vegetarian escape
in this matter, because he slays populations of beautiful little
creatures in a mouthful of lettuce or celery! Even if he lives
merely on cereals and vegetables, still the crops must be pro-
tected by the slaughter of innumerable small birds and beasts ;
and by what right does he snatch the milk from the cow or
her egg from the hen ? By what right do we go forth, gun on
shoulder, to shoot creatures for the mere amusement of our idle
hours ; or, rod in hand, to drag fish by means of cruel hooks
from the water ? Who has given us a charter to flog weary
horses in order to save us the labour of our own overfed bodies ;
or to whip dogs in order to train them to perform on their hind
legs ; or to keep wild animals and small birds in cages ? If it
comes to that, by what right do we slay the tiger, which follows
his own nature in taking toll of our flocks ; or the murderer who
attacks us ; or the innocent germs which live in our own blood ?
Still further; if all these things are to be forbidden, how shall
we deal with our humble relations of the animal kingdom, who
themselves do to others just as we do to them? Yet, in face
of this immense complex of fact, comes the irrationalist, who,
ignoring all the unnecessary cruelties of the world, tries to
argue that science may not do a few experiments in order to
lessen suffering due to disease !

Of course, the fact that Nature is "red in tooth and claw"
does not debar us from efforts to mitigate the sufferings of
animals; but those efforts must be logically directed towards
reducing unnecessary pain. Even the killing of animals for
food may partly be brought into this category, since we all eat
a great deal too much meat. But of all the sufferings of animals

IRRATIONALISM 5

caused by men, those only are ethically justifiable which are
caused, not for the sake oi gluttony, sloth, fashion, or amuse-
ment, but for the high object of reducing suffering among men
and other animals — that is to say, the very scientific experiments
which the irrationalist attacks !

His argument is therefore of no consequence, but it is of
interest to inquire how he reaches it. He does so merely by
considering the single sample. His mind is fixed on the experi-
ments alone, and all the innumerable other species and instances
of contact between men and animals become blurred in his
myopic vision. The only thing which he does see occupies the
whole of his mind, which has no room for more than one idea
at once. He becomes confused, and his judgment fails him —
like a hare's in the blaze of a motor-lamp. Indeed, so feeble
does his judgment become that, though he professes abhorrence
of all acts which cause pain, he himself generally continues to
eat meat, wear furs and feathers, and even enjoy sport ; and we
once heard a sportsman loudly condemning vivisectors at a
moment when a number of antelope and birds, just shot by him
for mere amusement, were lying dead in his verandah. Yet he
was quite a sane man — who indeed held a high post obtained by
competitive examination !

But this kind of person rarely stops at the mere innocent
irrationalism of inadvertence. He generally possesses enough
intelligence to feel the weight of the arguments which, later in
life, are brought against him ; but then his pride forbids him to
yield, and he has recourse to the invention of falsities to support
his credit as a reasoner. Thus the anti-vivisectionist invents
the utter untruths that experiments on animals have served no
useful purpose, and even that those who perform them do so in
order to gratify a supposed lust of cruelty. At this stage he is
past praying for ; he is no longer a reasoner, but merely one
who endeavours to escape conviction by the fabrication of evi-
dence, and nothing that others can say will ever persuade him
to retract a single one of his absurdities.

Irrationalism is, generally, the enemy of humanity. In the
form of crankism it clings shrieking to the hands of science just
when she is engaged upon her most difficult but beneficent
labours, and, in the form of political party, it paralyses the efforts
of the wisest legislators. It brings wars by encouraging race-
antagonism, and it lowers philosophy by false ideals. It will

6 SCIENCE PROGRESS

never cease because it is due to incomplete mental development ;
but the best way to reduce it is to give young minds that educa-
tion which allows them the widest purview — not the education
which forces them to burrow for ever in the dark pits of a single
knowledge, but that which leads them to look out early from the
summit of things upon the whole universe. In that way only
shall they learn how to avoid the life of the frog in the well, and
rather to view, like eagles, the true width of the world in which
they live.

In the meantime we should clearly understand that irra-
tionalism is due to a natural defect in the mind, amounting
sometimes almost to insanity. It is a defect of the reason
comparable to that defect of the vision which we call colour-
blindness ; but while colour-blindness is admitted by those
who suffer from it, because it does not affect their reasoning
powers (as, for example, in the distinguished case of Dalton),
those who suffer from reason-blindness are unable, from the
very deformity which afflicts them, to recognise their deficiency.
They therefore pursue their fad at all costs, whatever mischief
they may inflict by their efforts upon humanity or upon
individuals. And we see innumerable examples of this in our
present state of civilisation — anti-vaccination, anti-vivisection,
militant suffragism, anarchism, and nihilism are some of them.
It is a difficult question to know what to do with these forms
of semi-insanity. There is one way in which the press could
help towards disarming them — simply by placing their propa-
gandists on the same level as personalities, indecencies, and
libels, and by refusing to publish them. We think, however,
that the time has come when a more organised campaign should
be conducted against them by bringing certain forms of them
within the action of well-considered laws.

THE TEMPERATURE OF MARS

By PHILIP H. LING, M.Sc, Brist., B.Sc, Lond.

It is only comparatively recently that it has been found possible
to examine, with any approach to scientific method, the question
of the habitability of the planets. The ingenious theories of
Prof. Lowell have drawn attention to the possibilities pre-
sented by Mars, and though the problem is still far from
being settled, considerable advance has been made.

In discussing the question we have, of course, to limit our
inquiries entirely to life as we know it. Thus the planets
Jupiter, Saturn, Uranus, and Neptune appear to be in a semi-
molten state, which quite precludes any possibility of their
being inhabited. In fact, Mars and Venus seem to be the only
planets which are not ruled out by some unfavourable physical
condition, though the suggestion has been made that the
satellites of Jupiter may receive sufficient heat from their
primary to render some of them habitable.

Now the problem can be definitely solved only by the
appearance of some phenomenon which can be due to no
conceivable cause other than living intelligent beings. This
is what Prof. Lowell claims to have discovered in the case
of Mars. But while in view of the extreme diversity of opinion
concerning them in the astronomical world his theories cannot
be considered decisive, they may be supported or opposed
by a different type of argument. Such is supplied by an
examination of the physical conditions on the surface of Mars.
Unfortunately there is, even here, very considerable difference
of opinion. It is clear that the non-existence of oxygen in the
Martian atmosphere, if proved, would settle the matter at once ;
and the same would occur if the temperature were not some-
where in the neighbourhood of that prevailing on the earth.

But the question of temperature is even more intimately
connected with the subject. Prof. Lowell's " canal " theory
depends essentially on the idea that water is conveyed by

8 SCIENCE PROGRESS

artificial means from the polar regions. The theory is there-
fore quite untenable, unless the maximum temperature on Mars
is well above the melting-point of ice. There are two out-
standing determinations of the mean temperature, and the
great difficulty is that they appear to be absolutely contradictory.
The first is due to the late Prof. Poynting, 1 who, from a dis-
cussion of the general properties of solar radiation, finds the
mean temperature of Mars to be — 38 C. ; the second is that
of Prof. Lowell 2 himself, and leads to the value + 8° C. The
discrepancy, though less than 50° C, affects the whole question,
for if Prof. Poynting's value is correct, it is quite certain that
on Mars ice will never melt.

It is easy enough, under certain assumptions, to calculate
the mean temperature of Mars from that of the earth. Assuming
the two planets to be similar in their behaviour towards solar
radiation, and ignoring the central heat, we have that the
energy received from the sun is inversely proportional to
the square of the distance, while the energy given out is, by
Stefan's Law, directly proportional to the fourth power of
the absolute temperature. But since the temperature does not
vary much, the energy received must balance that radiated out,
so that the fourth power of the absolute temperature is inversely
proportional to the square of the distance from the sun ; or,
in other words, the absolute temperature is inversely pro-
portional to the square root of the distance. Taking the ratio
of the distances as 1*5237, and the mean temperature of the
earth as i5°C, we get that of Mars as — 39 C, practically
that obtained by Prof. Poynting.

Now we have here made the assumption that Mars and
the earth are similar in their behaviour towards solar radiation.
This is what Prof. Lowell denies.

The solar radiation on a planet may be either reflected or
absorbed. The reflected radiation plays no part in raising
the temperature. " Strange to say," remarks Prof. Lowell, 3
this important fact had never been taken into account till the
present investigation of the subject, which led to a completely
different outcome from what had previously been supposed."

1 " Radiation in the Solar System : its Effect on Temperature and its Pressure
on Small Bodies," Phil. Trans. A, 202 (1903), p. 525.

3 Mars as the Abode of Life (New York, 1909), pp. 240 et seq.
3 /bid. p. 83.

THE TEMPERATURE OF MARS 9

I do not think that this statement is quite just to Prof. Poynting,
in whose paper, as we shall see, the idea certainly occurs.
It is in the relative importance which they attach to it that
the two investigators differ so completely.

Prof. Poynting's paper not only deals with the temperatures
of different planets compared with that of the earth ; it also
gives a method by which the mean temperature of the earth
may be obtained absolutely. Strictly speaking, his results
apply only to an ideal planet, for which certain assumptions
are rigorously true. Most of these assumptions present no
difficulty as a basis for an approximate result. But with
regard to the absorbing power of the planet, Prof. Poynting
assumes that the reflection at each point is one-tenth of the
radiation received, justifying the assumption by the following
remarks : " This is probably of the order of the actual reflection
from the earth. According to Langley the moon reflects about
one-eighth of the radiation received. The earth certainly reflects
less. The temperatures determined hereafter are proportional
to the fourth root of the coefficient of absorption. Even if this
coefficient is as low as 0*9, its fourth root is 0*974. Hence if the
actual value is anywhere between 0*9 and 1, the assumed value of
o'9 will not make an error of more than 2\ per cent, in the value
of the temperature."

But is it between 09 and 1 ? The albedo (or fraction of
incident light reflected) varies enormously for different planets.
For Venus it is 0*92 and for Mars 0*27. In these cases the
proportion of incident light absorbed is therefore only 8 per
cent, for Venus, and actually 73 per cent, for Mars. It is of
course quite true that this applies only to the visible part of
the spectrum, and that there is a much greater proportion
of absorption in the infra-red; but on the face of it it seems
very unlikely that in the case of Venus the absorption is
anywhere near the value 90 per cent.

Unfortunately the value of the earth's albedo is highly
uncertain. The latest value, that of Prof. Very, 1 obtained
from the " earth-shine " on the moon, is 0-89 — i.e. nearly that
of Venus; but there are enormous difficulties in the determina-
tion. Prof. Lowell's value, estimated from the reflecting powers
of air, cloud, and the earth's surface, is 075. This has to be

1 Astronomische Nachrichten, 4696.

io SCIENCE PROGRESS

largely modified for the invisible rays, and the ratio ot the
absorbing coefficients comes out :

Earth _ 60
Mars 99

These figures give a value for the mean temperature ot Mars
equal to 22 C. ; this, however, has to be reduced owing to
difference in the rate of loss of heat, and the final result
is 8° C.

The question now arises : if Prol. Poynting's value of the
absorption coefficient is incorrect, how is it that his theory
gives an accurate value lor the earth's mean temperature ?
Prof. Poynting's theory gives the result :

6 = o"93# E = 0*93 x (eS/n-o-)'

where 6 and $e are respectively the average and equatorial
temperatures of the earth (in absolute Centigrade degrees),
e is the coefficient ol absorption, S is the solar constant (in
ergs per sq. cm. per sec), and o- is the radiation constant
(i.e. the constant of Stefan's Law). Now Prof. Poynting gets
three different values for 6, owing to uncertainty in the value
of S. These are 52 C, 29 C, and 17 C, corresponding to the
values of S obtained by Angstrom, Langley, and Rosetti
respectively. Expressed in ergs per square centimetre per
second, these values of S are respectively 0*28 x io 7 , 021 x io 7 ,
and 0*175 x io 7 . Prof. Poynting takes the third value of the
temperature as being that most in accordance with the fact,
under the assumption that e is 09. But if we put e = o*6, we
get the values of 6 as 22 C, i° C, and — n° C, and from this
it is clear that it is merely a question of choosing the solar
constant suitably. But now a serious difficulty arises.

Since Prof. Poynting's paper appeared, a long series of
determinations of the solar constant has been carried out by
Prof. Abbot. Of a number of values obtained in 1902-4, and
given in the Encyclopaedia Britaunica, 1 the mean is 2' 12 cal. per
sq. cm. per min., or ©"148 x io 7 ergs per sq. cm. per sec. A
later value given in a paper read before the American Philo-
sophical Society 2 in 191 1 is 1*93 cal. per sq. cm. per min. The
latest of all 3 is i'933 cal. per sq. cm. per min., or 0*135 ergs per

1 Art. " Meteorology."

* See Nature, Ixxxvi. p. 534 (June 15, 191 1).

3 See Nature, xciii. p. 198 (April 23, 1914).

THE TEMPERATURE OF MARS n

sq. cm. per sec. It is true that the value is not quite constant
(appearing to indicate that the sun is a variable star), but this
cannot have any great effect on the planetary temperatures.
If we substitute this value in Prof. Poynting's expression, then,
giving e its maximum possible value of unity, we shall not get
6 higher than 6° C, and since e must be considerably less than
i, the theoretical temperature must be still less. There is a
certain discrepancy here which still awaits explanation.

This, however, will not influence the temperature of Mars,
for S will not appear in the ratio of the temperatures of the
two planets. If the absorbing powers of the two planets are
sufficiently different — and the difference between the albedoes
of Mars and Venus seems to indicate the possibility — the
temperature of Mars need not vary much from that on the
earth.

The difference in the absorbing powers seems to be due,
as Prof. Lowell remarks, to a lack of clouds in the Martian
atmosphere. We know that clouds reflect 72 per cent, of the
incident light, and their permanent absence will cause the
greater absorption. The nights, however, owing to the rarity
of the atmosphere, may be very cold.

THE TERRESTRIAL DISTRIBUTION OF

RADIUM

By ARTHUR HOLMES, B.Sc, A.R.C.S., F.G.S.

Imperial College, London

Discussing the origin and duration of the sun's heat in 1862,
Lord Kelvin concluded that " the inhabitants of the earth cannot
continue to enjoy the light and heat essential to their life for
many million years longer," but he prudently added, " unless
sources now unknown to us are prepared in the great store-
houses of creation." To the geologist the extreme importance
of the radioactive elements lies in their fulfilment of Kelvin's
cautious qualification. Atomic disintegration is, in all known
cases, accompanied by a spontaneous evolution of energy which
ultimately appears in the form of heat. This unexpected discovery
was first announced in 1903 by Curie and Laborde, who showed
that radium was capable of maintaining a temperature slightly
above that of its immediate environment. Already Elster and
Geitel had begun to investigate the radioactivity of the
atmosphere. It was found that the air in caverns and cellars
was unusually high in its content of active matter, and this
led naturally to the view that the latter had escaped as radium
emanation from the soil. Impressed with the significance of
these observations, implying as they did a widespread distri-
bution of radioactive matter in the surface materials of the
earth, Professor (now Sir Ernest) Rutherford suggested in 1905
that the heat constantly evolved in virtue of the disintegration
of the earth's supply of radium might be sufficient to maintain
the observed temperature gradient. On the assumption that
100 calories per hour represented the heat output of one gram
of radium, he calculated that if each gram of the substance of

THE TERRESTRIAL DISTRIBUTION OF RADIUM 13

the earth contained 4*6 x io _u grams of radium, the heat so
produced would be equivalent to that brought to the earth's
surface by conduction and lost by radiation into space.

In the following year Rutherford's suggestion was quanti-
tatively put to the test by Professor Strutt, who devised a
method for determining minute quantities of radium, and applied

M.s\ m

PT^ ; ' , '" ; >,"" " T - Tj

Apparatus for the estimation of Radium.

The rock is brought into solution by fusion, treatment with water (alkaline solution) and treatment of the
resione with acid (acid solution). Each solution is stored up for a few weeks in a closed flask until
the equilibrium amount of emanation has accumulated. To estimate the radium in one of the solu-
tions the flask A containing; it is attached to the water condenser B. Emanation is expelled by vigorous
boiling, the steam condensing in B and falling back into A. At the end of an hour the cooling water is
run out of B and the steam then drives the emanation into c, after which the connection at D is closed.
Meanwhile the electroscope F has been exhausted and the air of the gasholder c, charged with
emanation, is passed into the electroscope through the tap at E. A measurement of the rate of
fall of the leaf then suffices to determine the amount of radium emanation present.

it successfully to a large number of representative rocks. 1 The
apparatus employed is figured in the adjoining illustration, to

1 See R. J. Strutt, Proc. Roy. Soc, A., vol. lxxvii. p. 475, 1906, and A. Holmes,
The Age of the Earth, London, 1913, p. 105.

i 4 SCIENCE PROGRESS

which a brief account of the mode of precedure is appended.
The results obtained were very surprising in the light of
Rutherford's calculation. The average of twenty-eight igneous
rocks gave 16 x io -12 grams of radium per gram of rock, about
thirty-five times as much as Rutherford had demanded for
thermal equilibrium of the earth.

Strutt's figures have been confirmed by several other
observers, and rocks from every continent have now been
examined. Prof. Joly, in his later measurements, employed a
method of extracting the radium emanation which avoids the
labour of preparing clear solutions of rock material. A mixture
of finely powdered rock and fusion mixture is heated in an
electric furnace, and the emanation is driven off with the expelled
gases. Carbon dioxide is absorbed in a soda-lime tube, and the
remaining gases, containing the emanation, are finally passed
into the electroscope, after which the rate of fall of the leaf is
measured just as in the solution method. 1 Joly's fusion method
gives consistently higher results than those obtained by the
solution method, but the reason for the discrepancy is not
altogether clear. There is no doubt that suspended particles
in the solution may bring about a partial occlusion of the
emanation, which would prevent a complete expulsion of the
latter by boiling, and would therefore lead to a low deter-
mination. 2

With careful chemical treatment, however, this source of
error may be avoided, and Mache has recently developed a
method of extracting emanation by aspirating air through the
solution, which renews our confidence in the accuracy of the
method devised by Strutt. 3 Mache has standardised his
apparatus directly with the Honigschmid radium standard,
and he finds that his results conform with surprising closeness
to those obtained from the same material when treated accord-
ing to Strutt's method of boiling out the emanation.

All the results obtained for igneous rocks up to the present
are summarised and analysed in the adjoining table.

1 Joly, Phil. Mag. vol. xix. p. 695, 1912.

3 Eve and Mcintosh, Phil. Mag. vol. xiv. p. 237, 1907 ; Trans. Roy. Soc.
Canada, series iii. p. 67, 1910 ; Joly, Phil. Mag. vol. xix. p. 695, 1912.
3 Mache (in the press, 1914).

THE TERRESTRIAL DISTRIBUTION OF RADIUM 15

Radium per Gram of Igneous Rocks in Billionths (io -11 )

of a Gram

The number of rocks included in the averages is given in the first of

each pair of columns

Observer.

Acid.

Intermediate.

Basic.

Ultrabasic

Strutt l . . .
Eve and Mcintosh 2
Farr and Florance 3
Schlundt and Moore 4 .
Buchner 5
Fletcher 6
Holmes 7

3
7
8

4
8

2-59

1-83
1 '95

2'6l

0-85
2'8o

-.#

15
20

2 4 *t

2*25
2-80
r68

1*64
0-85
2-45

9
6

4
5
4

0*52

0-54
073

071

0-85

4
lot

C46
0-51

Mean ....

4i
86

2-51

174

o-66

0*50

Joly 8 t.

3"oi

2-57

1-28

—

* Alkaline rocks.

+ Composite analyses.

Prof. Joly's results may also be expressed in the following
form, which brings out the connection between the mode
of occurrence of igneous rocks and their radium contents.
As before, the latter are stated in billionths (10 -12 ) of a gram per
gram of rock.

Type of Rock.

Acid.

Intermediate.

Basic.

Volcanic

Hypabyssal

Plutonic

} 23
63

3'9

18
IO
20

3'o

2-8

2"I

43
8

i'4

I'O

i'3

My own composite analyses were made by applying the
solution method to the three following sets of well-known
rocks, and the results obtained are given here because they
appear to fill important gaps in the data hitherto published.

1 Strutt, Proc. Roy. Soc, A., vol. lxxvii. p. 472, 1906.

2 Eve and Mcintosh, Trans. Roy. Soc. Canada, series iii. p. 69, 1910.

3 Farr and Florance, Phil. Mag. vol. xviii. p. 812, November, 1909.

4 Schlundt and Moore, Bull. U.S.G.S. 395, 1909.

s Buchner, Proc. Kon. Akad. v. Weten, Amsterdam, vol. xiii. p. 359, 1910;
vol. xiii. p. 818, 191 1 ; vol. xiii. p. 1063, 1912.

6 Fletcher, Phil. Mag. vol. xx. p. 36, July 1910; vol. xxi. p. 102, January 191 1 ;
vol. xxi. p. 770, June 191 1.

7 Holmes, The Age of the Earth, London, 191 3, pp. 130 and 182.

5 Joly, Phil. Mag. vol. xxiv. p. 694, October 1912.

16 SCIENCE PROGRESS

I. Volcanic and Hypabyssal Alkaline Rocks

i. Phonolite, Sokoto Hill, Mozambique.

2. Phonolite, Sanhuti River, Mozambique.

3. Solvsbergite, Sanhuti River, Mozambique.

4. Phonolite, Athi Plains, British E. Africa.

5. Phonolite, Black Hills, Wyoming, U.S.A.

6. Phonolite, Montreal, Canada.

7. Phonolite, Bohemia.

8. Phonolite, Wolf Rock, Cornwall.

9. Phonolite, Fernando Nironha Is., Brazil.

10. Leucitophyre, Reiden, Eifel.

11. Paisanite, Ailsa Craig, Firth of Clyde.

12. Tinguaite, Serra de Tingua, Brazil.

13. Solvsbergite, Gran, Hadeland, Sweden.

Average radium content of 13 rocks = 2*94 x io~ 12 grams per gram.

II. Plutonic Alkaline Rocks

1. Foyaite, Serra de Monchique, Portugal.

2. Ditroite, Ditro, Transylvania, Hungary.

3. Laurdalite, Laurdal, Norway.

4. Laurvikite, Laurvik, Norway.

5. Miaskite, Miask, Urals, Siberia.

6. Pulaskite, Fourche Mts., Arkansas, U.S.A.

7. Leucite Syenite, Serra de Caldus, Brazil.

8. Elaeolite Syenite, Serra de Tingua, Brazil.

9. Nepheline Syenite, Renfrew Co., Ontario, Canada.

10. Elaeolite Syenite, Langesund Fjord, Norway.

11. Elaeolite Syenite, Magnet Cove, Arkansas, U.S.A.

Average radium content of 11 rocks = 1*87 x io -12 grams per gram.

III. Plutonic Ultrabasic Rocks

1. Serpentine, Shetland Is.

2. Serpentine, Ballantrae, N.B.

3. Hornblende Peridotite, Portsoy, Banff.

4. Enstalite Peridotite, Assynt, Sutherland.

5. Serpentine, Knockdhu, Ayrshire.

6. Serpentine, Rhode Is., U.S.A.

7. Dunite, Lake Superior, Canada.

8. Dunite, Dun Mt., New Zealand.

9. Kimberlite, Transvaal.

10. Peridotite, East Griqualand.

Average radium content of 10 rocks =0-51 x io -13 grams per gram.

As yet the data are rather too scanty to justify more than
a few wide generalisations. Strutt's results indicated that on
the average the acid rocks were richer in radium than those
of more basic composition. Later determinations did not at first
altogether support this view, chiefly because of the remarkably

THE TERRESTRIAL DISTRIBUTION OF RADIUM 17

high values obtained by Joly. However, Joly's recent work
has replaced his earlier determinations by results more in
accordance with those of other analysts. Taking the averages
of the results obtained by the solution method, it will now be
seen, that with one exception, they indicate an unbroken pro-
portionality between the average amount of radium and the
average amount of silica in igneous rocks. The one exception is
afforded by the three determinations of Eve and Mcintosh,
which are as follows :

(Tinguaite ....
Tinguaite ....
Nepheline Syenite

Average .

A similar exception is illustrated by three radium analyses of
alkaline rocks made by the present writer :

4"3 x io~"

grams per gram

3'o x io~ 12

5> 55

I'lX IO -12

)) )'

2-8 x 10- 12

51 55

{Phonolite
Phonolite
Solvsbergite

2*83 x io -12 grams per gram.
4-10 x io- 12 „ „ „
2-26 x io- 12

and by the first of the following averages for alkaline rocks of
intermediate composition :

13 Volcanic (and Hypabyssal) Rocks
1 1 Plutonic Rocks

-12

Average

2"94 x 10^'- grams per gram.
1-87 x io- 12 „ „ „

2-45 x io~ 12 „ „ „

These results lead on to a further generalisation : that
alkaline rocks tend to be richer in radium than normal or
calc-alkaline rocks of similar acidity. Indeed, the extent to
which alkalies are present, and in particular, the extent to which
sodium is present, would appear to be the predominating factor
in determining the quantity of radium in a rock magma. The
association of radium with alkalies is more fundamental than its
association with silica, for it is the combination of silica with a
high proportion of alkali that favours the relative abundance of
radium.

Joly's results, which bring out very clearly the sympathetic
relation between the radium and silica contents of a rock,
also indicate the probability that volcanic, and, to a less extent,
hypabyssal rocks, are on the average more richly charged with
radium than their plutonic equivalents. My own determinations,

SCIENCE PROGRESS

and those of some other workers, point also to the same sig-
nificant conclusion. In the case of basic rocks, however, the
applicability of this generalisation is doubtful, and more analyses
are required before it can be extended to that class of rocks. It
is interesting to observe, in this connection, that volcanic rocks
contain more soda and more silica than the corresponding
plutonic rocks. With regard to potash, the volcanic rocks are,
if anything, poorer rather than richer, but the differences are in
this case variable and alternating. The following table is com-
piled from the average analyses of rock types collected by
R. Daly 1 and A. N. Winchell. 2 The distinction to which atten-
tion is drawn appears to hold too consistently to be assignable
to the particular choice of material ; rather is it an expression
of a real difference due to differentiation.

Comparison of Volcanic and Plutonic Rock Types

No. of
Analyses.

Types of Rocks.

Average perc
Silica, Si0 2 .

entages of
Soda, Na 2 0.

6 4
236

Rhyolite .
Granite

72*60
69*92

3*54
3-28

13
IO

Alkali Rhyolite .
Alkali Granite .

75'45
7270

5-88
5-42

48
13

Trachyte
Syenite

6o-68
58-06

4*43
3'67

17
23

Alkali Trachyte .
Alkali Syenite

62*46
61*99

6' 30
5'54

Phonolite .
Nepheline Syenite

57'45
54'63

8-84
8-26

30
20

Dacite
Tonalite

66-91

59"47

4'i3
2-98

16
12

Rhyo-dacite
Grano-diorite

67-67
55-10

4'io
3-82

57
70

Andesite
Diorite

61-30
56-77

3'99
3'39

18
10

Latite ....
Monzonite .

57 - 93
55'3o

4-19
373

198

Basalt
Gabbro

49'o6
48-25

3"n

2'55

1 R. Daly, Proc. Am. Ac. Arts, and Sci., vol. xlv. p. 211, 1910.
Igneous Rocks mid their Origin, pp. 13-39, New York, 19 14.
■ A. N. Winchell, Journ. Geo/., vol. xxi. p. 208, 191 3.

See also

THE TERRESTRIAL DISTRIBUTION OF RADIUM 19

Summing up, we may conclude that in general radium shows
a marked preference for alkaline and acid rocks, and to a less
extent for volcanic as compared with plutonic rocks. That is
to say, the processes of differentiation which are responsible for
the production of rocks rich in alkalies (particularly soda) and
silica, and incidentally for the difference in composition between
volcanic and corresponding plutonic rocks, are also responsible
for the relative concentration of uranium, and therefore of
radium. Although the evidence in the case of thorium is less
abundant than that for radium, it tends to show that similar
statements are equally true of that element. This is indicated
very forcibly by the well-known association of uranium-and-
thorium-bearing minerals with pegmatites, which, in turn, are
genetically related to granites and syenites of an alkaline
character. Occurrences in Norway, Finland, Greenland, Con-
necticut, and Ceylon sufficiently illustrate the statement.

The problem now arises whether there is any common
factor in the conditions governing the formation ot pegmatites
and alkaline rocks, which is also capable of extracting uranium
and concentrating it. The writer believes that such a common
factor may be found in the so-called " mineralising agents."
Among the minerals which are unable to crystallise except
under the influence of magmatic gases and vapours {e.g. water,
chlorine, fluorine, boron, sulphur oxides, etc.), are quartz, albite,
orthoclase, sodalite, haiiyne, amphiboles, micas, tourmaline,
topaz, zircon, sphene, beryl, and cassiterite. It is significant
that these are among the most characteristic minerals of pegma-
tites and alkaline rocks, and of acid rocks in general. Further,
we may observe, that among the "mineralising agents" are
just those gases which would combine with uranium and
thorium to form volatile and mobile compounds. It is therefore
suggested that, in a normal magma, selective differentiation
proceeds in such a way that the radioactive parent elements
are concentrated in those subsidiary portions of the magma
which ultimately give rise to pegmatites or to alkaline rocks,
the process of differentiation being largely controlled by
magmatic gases and vapours. For the same reason, the gaseous
emanations of active volcanoes may be the agents originally
responsible for the relatively higher percentages of soda and
silica carried by the lavas from which they escape.

How far similar principles may help to explain the origin of

20 SCIENCE PROGRESS

the granites which constitute so large a part of the outermost
layers of the earth's crust, it is as yet impossible to say. If, how-
ever, the hypothesis is true that the atmosphere, the oceans, and
the carbon dioxide represented by carbonaceous deposits and
limestones were all originally "juvenile" magmatic gases, then
it seems justifiable to assume that their escape did not take place
without profoundly affecting the nature and distribution of the
magmas which they helped to carry upwards and through which
they passed. It may be that the evolution of the earth's crust
and its peculiar chemical composition is to be correlated with
that of the oceans and atmosphere, the latter representing part
of the " mineralising agents " which helped to enrich the outer-
most, lighter, and more mobile magmas in silica and alkalies, and
their associates, at the expense of the deeper-seated, heavier, and
more viscous magmas.

Leaving these far-reaching speculations in petrogenesis, let
us return to the thermal significance of the radio-elements. In
order to calculate the total heating effect of the radio-elements
it is necessary to take into consideration the complete families
of uranium and thorium. Expressing the former in terms of
the equilibrium amount of radium, we have for the respective
heat outputs of the two families :

Radium per gram . . . 226 calories per hour.
Thorium 270 x io~ 7 „ „

If we take 2*5 x io~ 12 grams as the average radium content in a
gram of the crystal rocks, and 2'o x io -5 grams as the corre-
sponding average for thorium, then each gram of the earth's
crust is a source of heat emitting 565 x io~ 12 calories per hour
on account of its radium content, and 540 x 10 -12 calories per
hour on account of its thorium content. The total heat emission
per gram of the known crustal rocks is therefore of the order
1,105 x IO_12 calories per hour. It is important to notice here
that radium and its congeners are responsible only for approxi-
mately half of the earth's radiothermal energy, for thorium, in
virtue of its greater abundance, is equally potent as a generator
of heat.

The total amount of heat, Q, which escapes from the earth
by conduction to its surface and radiation into space, is given
by the formula :

THE TERRESTRIAL DISTRIBUTION OF RADIUM 21

Q = 47rr 2 .k.d#/dr calories per second,
where

4\r 3 , the area of the earth's surface = 51 x io 17 sq. cms.
k, the average conductivity of rock = 0*004,
and, d#/dr, the average observed temperature gradient

= i° C. for 32 metres
or 0-0003 i°C. per cm.

Substituting the given data in the above formula, Q is found to
be nearly 228 x io 14 calories per hour.

Thus, if each gram of rock generates 1,105 x io- 12 calories
per hour on account of its radioactive contents, it is clear that
2 x io 25 grams of rock would suffice to make good the earth's
loss. But the total mass of the earth is 600 x io 25 grams. Are
we therefore to suppose that the earth gains from radioactive
sources 300 times as much heat as it loses by conduction and
radiation ? Clearly we are in the face of a serious embarrass-
ment. It is impossible to believe that the earth is growing
hotter, not only for geological reasons, but also because our
planet could never have cooled beyond a state in which the gain
of radiothermal energy would just balance the loss of heat by
conduction. Equilibrium being once established, the earth
would continue to cool at the exceedingly low rate dictated
by the atomic decay of the parent elements, uranium and
thorium.

Since the earth is not growing hotter, a remarkable discrep-
ancy has to be explained. There are two ways of escaping
the difficulty, both of which were originally put forward by
Strutt. 1 It is possible that the average radium content of the
surface rocks is far above the average for the materials of the
earth when taken as a whole. The earth's store of radioactive
elements would then be concentrated in, and confined to, a mere
superficial shell, and distributed in such away that the observed
temperature gradient would be maintained solely by their
output of thermal energy. On the other hand, can it be granted
that in the deep interior of the earth the radio-elements would
continue to disintegrate and generate heat just as they do at
the earth's surface ? The parent elements may be present, but,
being subjected to high pressure and temperature, it is con-
ceivable that their decay may be inhibited. There would then
be within the earth an irregularly bounded zone extending to

1 Proc. Roy. Soc, A., vol. lxxix., p. 476, 1906.

22 SCIENCE PROGRESS

such a depth that at its base pressure and temperature would
attain certain critical values. Below that zone radioactive
processes would be inhibited by the excessive physical con-
ditions. Only in the outer shell would radioactive matter be
allowed to decay, and consequently only the rocks within that
shell could be appealed to as an active source of radiothermal
energy.

It is clearly of the greatest importance to geologists to
decide between these alternative but not mutually exclusive
views. Unfortunately it is impossible to come to a securely
founded conclusion, but such evidence as is now available may
profitably be reviewed. Let us take first the possibility of
radioactive inhibition. The suggestion is based on the well-
known reaction law of Le Chatelier, which states that the
internal reactions within a material system are such as will
tend to diminish the effect of any external influences by which
its equilibrium may be disturbed. Thus, under a rising tem-
perature, elements change their state or form new compounds
in such a way as to absorb energy, and so oppose the tendency
of the temperature to increase further. Similarly, under high
pressure, the atoms of a compound rearrange themselves so
that the molecular volume is reduced, and the ultimate stresses
by which the system would have been constrained are therefore
also reduced.

Dr. F. C. S. Schiller 1 suggests that uranium does not dis-
integrate in the earth's deep interior, or does so more slowly
than near the surface, and he thinks that radioactivity may
be an acquired habit of the substances that exhibit it. Dr. Leigh
Fermor 2 points out that the change from uranium to radium,
resulting as it does in an emission of energy, and, presumably,
an increase in atomic volume, is the kind of action which would
be inhibited by high pressure and temperature. Mr. H. S.
Shelton 3 is not content with inhibition only; he postulates
complete reversal. He thinks that " radioactive substances,
particularly uranium compounds, are synthesised from other
elements as a result of the conditions of great temperature and
pressure found in the earth's interior." This idea was originally
due to Dr. Barrell, 4 and has also been held by no less an

1 Nature, June 26, 1913, p. 424. 2 Nature, July io, 1913, p. 476.

3 Science Progress, No. 31, p. 456, 1914.

4 Rutherford, Radioactive Transformations, p. 194, 1904.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 23

authority than Arrhenius. 1 Rutherford, 2 however, has suggested
that at the enormous temperature of the sun it is possible that
a process of transformation may take place in ordinary elements
analogous to that observed in the radioactive elements. This
implies inhibition under conditions not of high but of low
temperatures.

Mr. Shelton himself, in an article on "The Age of the Sun's
Heat" 3 says, "Elements which are absolutely stable under
conditions which we can produce in our laboratories would, in
the colossal furnaces of stellar heat, change, decompose, and
gradually assume other and stabler forms." He then suggests
that such a transformation would make available sufficient
energy to maintain the sun's heat for thousands of millions of
years. What Mr. Shelton states, then, is this : that stable
terrestrial elements when subjected to high temperatures, such
as that of the sun, would assume stabler forms with emission
of energy. This is inconsistent with Le Chatelier's law of
reaction, for obviously at high temperatures the terrestrial
ejements would, according to that law, change into stabler forms
with absorption of energy. Apparently what is meant, however,
is that elements, stable under terrestrial conditions, would, if
present in a star or nebula, and subject to a high and rising
temperature, disintegrate into stabler forms with absorption of
energy. Later, when the temperature had begun to fall, this
process would be reversed, and the nebular or stellar elements
(e.g. helium and hydrogen) would re-unite with emission of
energy to build up the terrestrial types of elements, and so to
sustain the falling temperature. According to Mr. Shelton,
" Uranium and thorium are compounded beyond the limits of
stability." This implies that he believes that the radioactive
parent elements are formed with absorption of energy under
conditions of high and falling temperature, but that when
cooling has progressed sufficiently and the temperature is
lower, they again disintegrate with evolution of the energy
previously stored up. That is to say, that, under conditions
of falling temperature, energy is first absorbed and then
emitted.

However, quite apart from Mr. Shelton's self-made difficulty,

1 The Life of the Universe, vol. ii. p. 237, 1908.

2 Radioactive Substances and their Tratisformations, p. 656, 191 3.

3 Contemp. Review, p. 846, June 1913.

24 SCIENCE PROGRESS

there is a real discrepancy between the atomic disintegration
exemplified by radioactivity, the only type of which we have
any definite knowledge, and that which is implied by the
spectroscopic classification of stars and nebulae. In the latter,
the evolution of the elements would seem to proceed from
simple elements of low atomic weights, to more complex
elements of high atomic weights, the transformation being
attended by an emission of energy. In the case of radioactive
disintegration, on the contrary, complex elements of high atomic
weights break down with emission of energy into simpler
elements with lower atomic weights. Applying the law of
reaction to radioactive processes, it would be deduced that the
parent elements, uranium and thorium, should be stable at
sufficiently high temperatures, thus implying that they ought to
be characteristic elements in certain classes of stars, and in
any case, that they would there be less unstable than under
terrestrial conditions. Spectroscopic analysis indicates that in
stars of the hottest class, hydrogen and helium appear to be the
chief components. In stars of a less high temperature, oxygen,
nitrogen, and carbon appear. Silicon comes next, and finally,
at a much lower temperature, iron, manganese, calcium, and
other metals, including uranium, are introduced. Either the
spectroscopic evidence of the temperature and constitution of
the stars is insufficient and misleading, or Le Chatelier's law, in
so far as it refers to temperature changes alone, is not applicable
to the radioactive transformations. As a third alternative by
which the dilemma may be avoided, it may be suggested that
radioactivity is not primarily controlled either by temperature
or pressure, but by other physical conditions, possibly electro-
magnetic, in some way of which we are as yet entirely ignorant.
It is conceivable, for example, that the forms of hydrogen and
helium which exist in the hottest stars, may be very different
from the familiar terrestrial forms, so that they may represent,
either intrinsically or in virtue of their environment, an even
higher concentration of energy than the radioactive atoms. In
such a case it would be possible for the high temperature
elements to condense, with evolution of energy, to form the
radioactive elements as well as the more stable elements of
terrestrial conditions. Any changes of this kind, however,
could not be referable to temperature conditions alone, and it
seems impossible that they could take place in the interior of the

THE TERRESTRIAL DISTRIBUTION OF RADIUM 25

earth, for, involving as they would the emission of energy, they
would aggravate the very difficulty we are attempting to avoid.
We may therefore reasonably conclude that the radioactive
elements are not formed in the earth's interior from other
elements, although, if they are already present, their decay may,
nevertheless, be more or less inhibited.

The experimental evidence indicates on the part of the
radioactive elements an utter disregard for all the changes in
physical environment to which we can subject them. The effect
of temperature has been investigated by several observers, 1 and
their results lead to the final conclusion that atomic trans-
formation proceeds at the same rate at all temperatures between
— i86°C. (liquid air) and 1,500° C. Quite recently Giebeler 2
found lines in the spectrum of Nova Geminorum (2), which have
been identified with those of uranium, radium, and radium-
emanation, and Dyson 3 has shown that similar lines can be
observed in the spectrum of the sun's chromosphere. It would
therefore appear that radioactivity is not inhibited by a
temperature of 6,ooo° C. or 7,000° C. It has been found that
pressures ranging to 2,000 atmospheres are without influence on
the activity of radium. Radium emanation introduced into a
high-pressure bomb was unaffected by a temperature of
2,500° C. and a pressure of 1,000 atmospheres.

Two other types of phenomena lead to apparently different
conclusions. All elements are known to emit electrons when
under the influence of ultra-violet light, which indicates that
the atom is not altogether indifferent to external influences.
Further, the vibrations which give rise to spectrum lines are
damped slightly by increase of pressure, so that the lines are
displaced towards the red. Strictly, however, this phenomenon
is due less to pressure as such than to increase of density {i.e.
closer packing of the molecules), for, as Larmor has pointed out,
mechanical pressure arises from the translatory motions of
molecules, which are too slow to have any detectable influence
upon radiation periods. As the density is increased, however,
the electrons to which the radiations are due are brought into
closer association with surrounding electrons, and the vibrations

1 Rutherford, Radioactive Substances, p. 502, 191 3. Russell, Proc. Roy. Soc,
A., vol. lxxxvi. p. 240, 1912.

' Astr. Nachr., 191, no. 4,582, June 1912.
3 Ibid., 192, no. 4,589, July 191 2.

26 SCIENCE PROGRESS

then emitted differ slightly from those corresponding to the
natural periods of the electrons.

According to the model now favoured by the leading
physicists the atom consists essentially of two strongly contrasted
portions. There is a central system or nucleus surrounded
by an intense electric field, and it is in the nucleus that the
mass of the atom is mainly concentrated. Here, also, the
positive charge of the atom is situated. Only a few negative
electrons are present in the nucleus, and it is they which deter-
mine the column occupied by an element in the Periodic Table. 1
Around the nucleus is an outer shell of electrons, and it is to
the latter that chemical and all the common physical phenomena
are to be referred. Such phenomena are in general reversible,
because the atom may lose those electrons and regain them from
external sources. The above-mentioned experimental results,
from which it is deduced that the atom is affected by increase of
density and by the impact of ultra-violet waves, are concerned
only with the outer ring of electrons. They therefore leave the
question at issue untouched, for radioactivity is primarily con-
trolled by changes in the central nucleus.

In the uranium atom the nucleus has, according to the theory
developed by Rutherford, a diameter of the order of i/io,oooth
of that of the whole atom. 2 For some reason this central
system becomes actively unstable and a component a-particle
or positively charged helium atom escapes. In passing through
the electric field, it rapidly gains kinetic energy, and finally is
violently expelled from the parent atom with a velocity of about
2 x io° cms. (12,000 miles) per second. The temperature equiva-
lent of this velocity in the case of helium is easily calculated to
be about 65,000,000,000° C. 3 This result, of course, is meaning-
less, but it serves a useful purpose in suggesting the intense
concentration of energy which is involved, and further, it
indicates that radioactive processes are controlled more by
electric than by thermal phenomena. Moreover, if pressure is
due to the translatory motions of molecules, it seems impossible
that the impulsive forces thus set up should ever prove equal to
the task of imposing inactivity upon a radioactive atom.

It has been suggested as a possible effect of high pressure

1 Soddy, Chemistry of the Radio Elements, part ii. p. 41, 1914.

2 Rutherford, Phil. Mag., vol. xxi. p. 669, 191 1.

3 Ramsay, Elements and Electrons, p. 149, 191 2.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 27

that owing to the closer packing of the atoms, intense repulsive
forces between adjacent nuclei, or between neighbouring groups
of electrons, might be setup, and that this would tend to prevent
escape of the a- and /3-particles. This seems to be plausible,
but until the dimensions of atoms are known with sufficient
accuracy to investigate their individual average densities and
their mutual spatial relations, it is impossible to decide whether
an increase of molar density due to pressure could, within the
earth, suffice to induce inhibition. At present it would appear
that unless the density of a solid were increased many times by
the application of pressure — a condition which is certainly
unrepresented in any part of our planet — then the suggested
cause would be inadequate to explain the hypothetical pheno-
menon attributed to it.

Experimental evidence, as far as it goes, supports these
theoretical considerations, for, although experiments have been
made in the hope of detecting some change when radioactive
substances are vigorously bombarded with a-, /3-, and 7-rays, no
effect has been observed. It would, for example, be reasonable
to suppose that when radium emanation is disintegrating, a
small amount of radium, the immediate parent of the emanation,
might be formed by the re-introduction into the latter of newly
liberated a-particles. Rutherford has experimented on these
lines with a number of substances, but in no case has evidence
been obtained that the process of transformation is reversible.
It is, unfortunately, impossible to arrive at a satisfactory con-
clusion, but (a) experimental results, (b) theoretical considerations
based on the constitution of the atom, the violence of atomic
decay, and the incompressibility of solids, and (c) spectroscopic
evidence of stellar and atomic evolution, all tend to the final
suggestion that atomic disintegration is mainly controlled by
conditions other than those of pressure and temperature.

This necessarily vague conclusion can scarcely form a sound
basis on which to build a theory of the terrestrial distribution
of radium. It certainly points to the probability that the radio-
elements, if they were distributed throughout the substance of
the earth, would disintegrate much as they are known to do at
the surface, and that, since the earth is not growing hotter, the
radio-elements are therefore limited in their occurrence to a
comparatively thin superficial shell. In justice to the evidence,
no more definite statement than this can be made. We must

28 SCIENCE PROGRESS

therefore consider the constitution of the earth itself, and, from
what little knowledge we have, attempt to deduce the probable
distribution of radium. It is no more absurd for the geologist
to speculate on the interior of the earth than it is for the
physicist to postulate the architecture of an atom. Both earth
and atom have an outer shell with which we are to some extent
familiar. Both have a central core or nucleus which is not
amenable to direct observation ; but the one is not more in-
accessible than the other. The atom is penetrated by the
Becquerel rays ; the earth is inwardly explored by earthquake
waves.

In 1900, Dr. R. D. Oldham 1 showed that the disturbances
due to an earthquake may be analysed into three distinct
forms of wave motion, which, after passing around or through
the earth, give rise to three different phases in their distant
record. The third phase is attributable to surface waves, and
with these we need not here concern ourselves. The first and
second phases are due respectively to waves of compression
and waves of distortion, the former travelling much more rapidly
than the latter. Traversing the heterogeneous rocks of the
earth's crust, the two types of waves cannot be readily dis-
tinguished. However, as soon as they sink (at a depth of say
20 miles) into the homogeneous material that lies below, they
are sorted out in virtue of their different velocities, and at a
distance of 700 miles from their source two distinct records
may be detected, each referable to the same original shock.

If the velocity of waves transmitted through a medium re-
mains constant, then the wave motion is propagated in all
directions in straight lines. If, however, the velocity varies
owing to internal constitutional changes, the wave path is re-
fracted. Now, since refraction of earthquake waves actually
occurs within the earth, we are able to learn something about
the variation of the physical conditions of the interior. When
massive waves are propagated through the body of the earth,
they travel faster as they penetrate to greater depths, provided
that the maximum depth does not exceed 2,000 miles. There
appears to be, according to Oldham, 2 a well-marked surface
of physical discontinuity at a depth of between 2,000 and 2,400
miles, for, when the waves penetrate still more deeply, there

1 Phil. Trans. Roy. Soc, A., vol. cxciv. p. 135, 1900.
1 Nature, August 21, 1913, p. 635.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 29

is a remarkable decrease in their rates of propagation, a fact
which indicates a high degree of resistance to compression, and
therefore a marked change in constitution.

Oldham ! originally suggested a thickness of about 20 miles
for the outer shell of heterogeneous and fractured rocks which
surrounds the homogeneous zones of the interior, and which
we may conveniently describe as the earth's crust. He has
now 2 halved his former estimate and gives 10 miles as a
probable value. The late Prof. Milne 3 in 1906 deduced a
thickness of 30 miles from the data then at his disposal.
These varying figures may mean that the thickness itself
varies from place to place, but in any case they are certainly
of the right order. Some recent experiments by Adams 4 have
demonstrated that under the conditions of pressure and
temperature believed to obtain in the earth's crust, empty
cavities may exist to a depth of at least 11 miles. King 5
has similarly shown that small cavities will remain open at
all depths up to about 20 miles, provided that the temperature
is not excessive. We may therefore conclude that the earth's
crust as defined above is at least 10 miles thick and may be
more than 20.

According to Wiechert, 6 the earth is built up essentially of
two strongly contrasted zones separated somewhat sharply by
a surface of discontinuity at a depth of about 950 miles. An
inner core of mean density 7*8-8o is postulated, this being
surrounded by a rocky mantle having a mean density of about
3*4. Oldham finds a surface of discontinuity beneath the
Pacific at a depth of 1,000 miles, 7 which is in close agreement
with Wiechert's results, but for the main body of the earth
he gives 2,000-2,400 miles as the probable depth. The whole
subject, however, is still in its infancy, and the discrepancies
suggest that the problem is less simple than these pioneer solu-
tions would indicate. That this is undoubtedly the case is
shown by more recent work. K. Zoeppritz, L. Geyer, and
B. Gutenberg have made an exhaustive study of the earth-

1 Q.J.G.S., vol. lxii. p. 456, 1906.

2 Nature, August 21, 19 13, p. 635.

3 Milne, Bakerian Lecture, Proc. Roy. Soc, A., vol. lxxvii. p. 365, 1906.

4 Journ. Geo?., vol. xx. p. 97, 1912.

5 Ibid. vol. xx. p. 119, 1912.

6 Deutsche Rundschau, pp. 376-94, 1907.

7 QJ-G.S., vol. lxiii. p. 344, 1907.

3 o SCIENCE PROGRESS

quake records received at Gottingen during the years 1904-
191 1, and as a consequence they have been able to distinguish,
not two zones alone, but four, separated by marked physical
discontinuity at depths of approximately 750, 1,060, and 1,530
miles. 1 The Wiechert law of density must be correspondingly
modified. Beneath the outer crust, which has a mean density
of about 2 - 8, are four zones, of which the outer one has
probably a density of 34; the inner being as before about
7 , 8-8 , o. The two intermediate zones, which are of less bulk
than the others, are presumably characterised by intermediate
densities. This conclusion is more likely to be in accordance
with the facts than Wiechert's, for it implies a gradual down-
ward increase of density in place of a relatively sudden change.

It is manifestly impossible ever to know directly the
chemical constitution of the earth's interior. However, we may
study in the laboratory the disrupted fragments of some other
world, 2 for it is now believed that meteorites were once
arranged according to their densities as parts of a cosmic body.
If this be true it seems highly probable that the constitution of
the meteoritic parent body thus determinable was essentially
similar to that of the earth. Let us briefly review the evidence
in favour of these suggestions.

Meteorites may be divided into five well-marked classes
according to the relative proportions of their metallic and stony
constituents. The iron meteorites, which are known as
holosiderites, consist almost entirely of a coarsely crystalline
nickel-iron alloy (average density 78). The dimensions and
uniformity of structure of the giant metallic crystals of many
iron meteorites indicate that they crystallised very slowly from
a magma which remained for a long period at a nearly uniform
temperature not far below the fusion point. This in turn
suggests that most of the holosiderites were formed in the
deep interior of the parent body, where the pressure would
be high.

It has been conjectured that the well-known Widmanstatten
figures represent an internal structure which may have been
due either to (a) very slow crystallisation, (b) sudden chilling

1 Gessellwiss Gottengen Nachr. Nath. Phys. Klasse, 2, pp. 121-206, 1912; 6,
pp. 625-75, 1912.

* Chamberlin, Journ. Geo/., vol. ix. p. 369, 1901. See also a valuable series
of papers by Farrington in the same volume.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 31

subsequent to solidification, or to (c) the effects of high pressure.
The second view supports the hypothesis that meteorites
are the scattered fragments of a suddenly disrupted and there-
fore suddenly chilled cosmic body; the first and last that
holosiderites came from the central core of such a parent body,
i.e. where cooling would be long delayed, and mechanical
pressure would be at its maximum.

The octohedral form of many of the crystals betrays in part
their past thermal history, for it proves that the temperature
which conditioned their growth must have exceeded 86o° C.
One effect of high pressure would be, of course, to raise this
lower limit very considerably.

Lithosiderites are meteorites which consist of a nickel-iron
matrix containing granules of basic silicates such as olivine
and bronzite. When the silicate minerals preponderate over
the metallic alloy so that the latter occurs in grains embedded
in stone, the meteorite is known as a siderolite. The nickel-
iron in these two types is also generally of octohedral form,
and exhibits the Widmanstatten figures. Equally significant
is the presence of tridymite, a crystalline form of silica
which is stable between temperature limits of 8oo° C. and
1,625° C.

The stone meteorites proper are divided into chondrites and
achondrites according to the presence or absence respectivel} 7
of peculiar rounded masses of olivine or pyroxene, which are
known as chondri or chondrules. The origin of these puzzling
structures as yet is not understood, for they have no known
terrestrial analogues. 1 Some of the meteoric stones have cer-
tainly crystallised from a molten magma, and may be paralleled
with the ultra-basic rocks. Others, however, have a clastic
or fragmental structure, and seem to be of the nature of volcanic
tuffs and breccias, to which they bear a close resemblance.
The common presence of a crypto-crystalline matrix, or a
dark basic glass, affords clear evidence of rapid cooling. These
features point to the superficial conditions under which some
of the stones were originally formed.

Dr. Prior 2 has recently shown ,that there is a striking
similarity both in the chemical and mineralogical compositions of

1 For an interesting suggestion see Fermor, Rec. Geol. Surv. India, vol. xliii.

1913, PP- 41-47.

2 Mi?i. Mag. vol. xvii. p. 33, 1914.

32 SCIENCE PROGRESS

chondritic stones, all of which approximate to the following
type:

Nickeliferous Iron (Fe/Ni = io/i)
Troilite (FeS).
Olivine (Mg/Fe =■ 3/1) .
Bronzite (Mg/Fe = 4/1) .
Oligoclase ....
Chromite ....

• 9
. 6

• 44

• 3o
. 10

100

If such a close correspondence were found in a series of
terrestrial rocks, they would be said to present a high degree
of consanguinity. The evidence points directly to community
of origin, both as regards the chemical constitution of the magma
from which they crystallised, and the physical conditions which
determined their structures.

It is a noteworthy feature in the fragmental meteorites
that no trace of stratification, foliation, or weathering has
ever been observed. Moreover, the minerals which require
the presence of "mineralising agents" in order to crystallise
successfully are one and all absent from meteorites. Olivine is
never altered to serpentine, nor felspar to kaolin, or sericite, or
epidote. The minerals are throughout fresh and unaltered.
These facts may be interpreted as showing that the parent body
was lacking in the gases and vapours which would have pro-
moted mobility of the magmas and selective differentiation, and
that consequently it was devoid of a " crust " such as that of the
earth, and was also without an appreciable atmosphere or ocean.

That the parent body had already cooled well into its interior
at the time of disruption is proved in a most striking way by the
occurrence of combustible hydrocarbons in certain meteoric
stones, and also in a limited but well-defined group of carbon-
aceous meteorites. The latter, having a very low density and
an unusual composition, may possibly represent whatever
" crust " the parent body possessed. The presence of hydro-
carbons implies that ever since their formation the meteorites
which carry them can never have been subjected to any but low
temperatures. During the swift flight through the atmosphere
the superficial skin of a meteorite is fused, but its interior,
already chilled by its passage through space, remains cold,
and so continues to preserve the volatile compounds from
destruction.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 33

The mean densities of the chief groups of meteorites are
classified in the following table :

Type of Meteorite. Mean density.

^chondrites I g ( 3 '2 J

Chondrites ) t 3*5 )

Siderolites 1 Iron . stone . . . U'8 >
Lithosidentes ) <. 6*5 >

Holosiderites Iron 7*8

The achondrites do not widely differ in chemical composition 1

from terrestrial ultra-basic rocks. The chondrites are also very

similar, except as regards the small proportion of free metal

which is usually present, and even this can be matched in certain

terrestrial rocks which carry native iron. The field relations of

the ultra-basic rocks, as well as their superior density, indicate

that they are genetically connected with a deep-seated zone

which underlies the more acid rocks of the earth's crust. On

the meteoritic analogy, which is based as much on structures as

on densities, it may be assumed that they extend to the first

surface of discontinuity, so constituting not only the deeper

portions of the crust itself, but also the first great zone which

lies beneath it. The second zone would presumably be formed

of material like that of the siderolites ; the third would compare

closely with the lithosiderites, and, finally, corresponding to the

holosiderites, would come the central metallic core. On this

distribution the mean density of the earth would be 5 ' 1 . Although

the earth's actual mean density is 5-53, the discrepancy is not

without significance, for it is highly probable that under the

pressures obtaining in the ultra-basic zone minerals would form

of higher density than those in the stone meteorites. It has

been suggested by Fermor that the reason why such minerals

{e.g. garnet) do not occur in meteorites is that a general recrystal-

lisation would accompany the disruption of, and consequent

relief of pressure in, the parent body.

The view that meteorites allow us to read at our leisure
many of the secrets which are otherwise locked up in the earth's
interior was originally held by Boisse, 1 Meunier, 2 and Daubree, 3
who arranged meteorites according to their densities, and founded
an analogy solely on that arrangement. The same idea has more

1 Mem. de la. Soc. des Lets. Sci. et Arts de VAveyron, vol. vii. p. 168.

1 Cours. de Geol. ComparSe.

3 Suess, The Face of the Earth (Eng. trans.), vol. iv. p. 543.

34 SCIENCE PROGRESS

recently been developed by Farrington, 1 who, however, was led
to his hypothesis from a study of the structural characters of
meteorites. Suess 2 has further supported the parallel on account
of the remarkable and detailed correspondence between the
qualitative chemical composition of the ultra-basic rocks of
the earth's crust and that of the stony material in meteorites.
He proposes three zones as determining the structure of the
earth : Nijc (Ni, Fe), the metallic barysphere ; Sima (Si, Mg),
the intermediate zone ; and Sal (Si, Al), the outer crust.
Merrill 3 has also investigated and discussed the chemical
characters of meteorites, and his results show that the elements
which he was unable to detect are chiefly those which are least
characteristic of terrestrial ultra-basic rocks, and which are, in
fact, never abundant on the earth except in acid or alkaline rocks.

As we have seen above, the parallel can now be carried
further than ever before, for to each type of meteorite there
corresponds a terrestrial zone of such dimensions that the
density requirements are satisfied as closely as could reasonably
be expected. In view of this analogy between meteoritic and
terrestrial materials, it appeared to the author that it would be of
great interest to investigate in detail the radioactive characters
of meteorites. Only a few preliminary results have so far been
obtained, but they seem to be particularly significant. Radium
estimations have been made of the following composites,* this
method of analysis having been rendered necessary because
the available quantity of each individual specimen was too
small to allow of separate treatment. The specimens were
detached from a small collection which belongs to the
Geological Museum of the Imperial College of Science and
Technology, by permission of the authorities of the College,
to whom I wish here to express my thanks. The results may
be summarised, together with those for average rock types, in
the table opposite.

In 1906 Prof. Strutt 4 estimated the radium in the Dhurmsala
stony meteorite, and found it to contain C56 x io~ 12 grams per
gram. In the case of three iron meteorites, however, he was

1 Jourtt. Geol., vol. ix. p. 623, 1901.
3 Loc. cit., p. 544.

3 Am. Journ. Set., vol. xxvii. p. 469, 1909; vol. xxxv. p. 509, 1913. See also
Wahl, Zeit. anorg. Chem. t vol. lxix. p. 52, 1910.

4 Proc. Roy. Soc., A., vol. lxvi. p. 480, 1906.

THE TERRESTRIAL DISTRIBUTION OF RADIUM 35

Type of Material.

Density.

Radium.

Silica.

Alkalis.

Plutonic Rocks :

Acid

2-65

Intermediate

2'8o

Basic .....

2-95

Ultra-basic ....

3-20

0-5

Meteorites :*

Stone .....

3*4

0'25

Iron-stone ....

5*5

o"i

Iron .....

7-8

Silica and alkalis are given in percentages. Radium is stated in units of
billionths (io~~ 12 ) of a gram per gram of material. For a useful collection of
analyses of meteorites, see Farrington, Field Columbian Museum Publications,
Chicago, Geological Series, vol. iii. nos. 5 and 9. For details of the classification
of meteorites, see Brezina, Proc. Am. Phil. Soc, vol. xliii. p. 211, 1904.

* The composites were made up of the following groups of meteorites :

(8) Stone Meteorites : [Radium averages C25 x io — I2 grams per gram.]
(a) Achondrites : Stannern, Nagy-Borove, and Bluff.

{&) Chondrites : LAigle, Charsonville, Dhurmsala, Pultusk, and Knya-
hinya.
(4) Iron-Stone Meteorites : [Radium averages o'iox 10— Vi grams per gram.]

Lithosiderites and Siderolites : Estherville, Pallas Iron, Vaca Muerta
and Dona Inez.
(3) Iron Meteorites : [No radium detectable.]

Holosiderites : Youndegin, Staunton, and Toluca.

unable to detect a measurable quantity. Native iron from
Disco, Greenland, contained o'2i x io -12 grams per gram, this
being probably associated with the silicate minerals also present
in the specimen.

In their natural occurrence there would thus appear to be
a strong chemical antipathy between uranium and iron, and
it will now be clear that if the meteoritic analogy is true, or
if for any other reason it is believed that metallic iron is the
chief constituent of the earth's internal core, then there is
considerable evidence that the latter is entirely devoid of
uranium. It may be objected that if the stony material of
the earth were charged throughout with the same amount
of uranium (or radium) as is the stony material of meteorites,
there would still be an embarras des richesses, as regards the
thermal output of the whole. The analogy, however, must
not be pushed too far, and quantitative equivalence is not sug-
gested. It is impossible, for example, that meteorites (or

36 SCIENCE PROGRESS

planetesimals of an identical average composition) could have
built up the earth, because in many respects (e.g. lack of
minerals which require the presence of mineralisers ; deficiency
in potash, etc.) the crustal rocks derived from them would have
been somewhat different in composition from those with which
we are familiar. In so far as the crust is the result of a long
and cumulative process of differentiation, it represents in a
highly magnified or exaggerated way, the detailed chemical
peculiarities of the materials from which the earth was formed.

Summing up, we have seen that in the earth itself radium
and its congeners are undoubtedly more abundant in the upper
parts of the crust, and that in successive layers the radium
content rapidly decreases with depth. In meteorites, radium
is found in small quantities in the silicate minerals, but is
absent from the nickel-iron alloy. That is to say, the per-
centage of radium in each successive zone of the parent body
gradually decreased with depth, until ultimately it died out
altogether. It is suggested that, in the case of the earth, the
decrease of radium with depth does not stop at the point where
our means of observation come to an end, but that it continues
until at last the radium content is reduced to zero. If within
the depth to which the radio-elements extend, pressure and
temperature are ineffective in preventing or inhibiting atomic
decay, then the total quantity of the earth's store of the radio-
elements is calculable with some accuracy.

The problems that are suggested by the general conclusions
of this inquiry are of supreme geological importance. The
evolution of the earth, of its zonal structure, and particularly
of its crust are all questions which remain to be solved. The
thermal history of the earth must be investigated afresh.
Volcanic phenomena, and the differentiation and movements
of molten magmas receive a new significance. To enter into
these wider problems l would lead us farther afield than the
title of this paper would justify, but its purpose will have been
served if it affords a basis for future discussion, and indicates the
special subjects concerning which the geologist urgently desires
extended knowledge and more securely founded conclusions.

1 In this connection the following may be referred to : J. Joly, Radioactivity
and Geology, pp. 154-82, 1909; T. C. Chamberlin, Journ. Geol., p. 673, 191 1;
A. Holmes, Nature, p. 398, June 19, 1913, The Age of the Earth, p. 30, 1913 ;
L. L. Fermor, Geol. Mag., p. 65, 1914.

THE BIRTH-TIME OF THE WORLD 1

By J. JOLY, Sc.D., F.R.S.

Professor of Geology and Mineralogy, Trinity College, Dublin

Long ago Lucretius wrote : " For lack of power to solve the
question troubles the mind with doubts, whether there was
ever a birth-time of the world and whether likewise there is
to be any end." "And if" (he says in answer) "there was no
birth-time of earth and heaven and they have been from ever-
lasting, why before the Theban war and the destruction of
Troy have not other poets as well sung other themes ?
Whither have so many deeds of men so often passed away,
why live they nowhere embodied in lasting records of fame ?
The truth methinks is that the sum has but a recent date,
and the nature of the world is new and has but lately had
its commencement." 2

Thus spake Lucretius nearly 2,000 years ago. Since then
we have attained another standpoint and found very different
limitations. To Lucretius the world commenced with man, and
the answer he would give to his questions was in accord with
his philosophy : he would date the birth-time of the world from
the time when poets first sung upon the earth. Modern
Science has swept utterly away this beautiful imagining, along
with the theory that the earth dated its beginning with the
advent of man. We can, indeed, find no beginning of the
world. We trace back events and come to barriers which
close our vista— barriers which, for all we know, may for ever
close it. They stand like the gates of ivory and of horn ;
portals from which only dreams proceed ; and Science cannot
as yet say of this or that dream if it proceeds from the gate of
horn or from that of ivory.

In short, of the earth's origin we have no certain knowledge ;

1 A lecture delivered before the Royal Dublin Society, February 6, 1914.

2 H. A. J. Munro, De Rerum Natura (Cambridge, 1886).

38 SCIENCE PROGRESS

nor can we assign any date to it. Possibly its formation was
an event so gradual that the beginning was spread over
immense periods. We can only trace the history back to
certain events which may with considerable certainty be
regarded as ushering in our geological era.

Notwithstanding our limitations the date of the birth-time
of our geological era is the most important date in Science.
For in taking into our minds the spacious history of the
universe, it must play the part of time-unit upon which all our
conceptions depend. If we date the geological history of the
earth by thousands of years, as did our forerunners, we must
shape our ideas of planetary time accordingly; and the duration
of our solar system, and of the heavens, becomes comparable
with that of the dynasties of ancient nations. If in millions
of years the sun and stars are proportionately venerable. If
in hundreds or thousands of millions of years the human mind
must consent to correspondingly vast epochs for the duration
of material changes. The geological age plays the same part
in our views of the duration of the universe as the earth's
orbital radius does in our views of the immensity of space.
Lucretius knew nothing of our time-unit : his unit was the
life of a man. So also he knew nothing of our space-unit, and
he marvels that so small a body as the sun can shed so much
heat and light upon the earth.

A study of the rocks shows us that the world was not
always what it now is and long has been. We live in an epoch
of denudation. The rains and frosts disintegrate the hills ; and
the rivers roll to the sea the finely divided particles into which
they have been resolved ; as well as the salts which have been
leached from them. The sediments collect near the coasts of
the continents ; the dissolved matter mingles with the general
ocean. The geologist has measured and mapped these de-
posits and traced them back into the past, layer by layer. He
finds them ever the same : sandstones, slates, limestones, etc.
But one thing is not the same. Life grows ever less diversified
in character as the sediments are traced downwards. Mammals
and birds, reptiles, amphibians, fishes, die out successively in
the past ; and barren sediments ultimately succeed, leaving the
first beginnings of life undecipherable by him. Beneath these
barren sediments lie rocks collectively differing in character
from those above : mainly volcanic or poured out from fissures

THE BIRTH-TIME OF THE WORLD 39

in the early crust of the earth. Sediments are scarce among
these materials. 1

There can be little doubt that in this underlying floor of
igneous and metamorphic rocks we have reached those surface
materials of the earth which existed before the long epoch of
sedimentation began, and before the seas came into being.
They formed the floor of a vapourised ocean upon which the
waters condensed here and there from the hot and heavy
atmosphere. Such were the probable conditions which pre-
ceded the birth-time of the ocean and of our era of life and
its evolution.

It is from this epoch we date our geological age. Our next
purpose is to consider how long ago, measured in years, that
birth-time was.

That the geological age of the earth is very great appears
from what we have already reviewed. The sediments of the
past are many miles in collective thickness : yet the feeble silt
of the rivers built them all from base to summit. They have
been lifted from the seas and piled into mountains by move-
ments so slow that during all the time man has been upon
the earth but little change would have been visible. The
mountains have again been worn down into the ocean by
denudation and again younger mountains built out of their
redeposited materials. The contemplation of such vast events
prepares our minds to accept many scores of millions of years
or hundreds of millions of years, if such be yielded by our
calculations.

The Age by the Thickness of the Sediments

The earliest recognised method of arriving at an estimate
of the earth's geological age is based upon the measurement
of the collective sediments of geological periods. The method
has undergone much revision from time to time. Let us
briefly review it on the latest data.

The method consists in measuring the depths of all the
successive sedimentary deposits where these are best developed.
We go all over the explored world, recognising the successive
deposits by their fossils and by their stratigraphical relations;

1 For a description of these early rocks, see especially the monograph of Van
Hise and Leith on the Pre-Cambrian Geology of North America (Bulletin 360,
U.S. Geol. Survey).

4 o SCIENCE PROGRESS

measuring their thickness and selecting as part of the data
required those beds which we believe to most completely
represent each formation. The total of these measurements
would tell us the age of the earth if their tale was indeed
complete, and if we knew the average rate at which they
have been deposited. We soon, however, find difficulties in
arriving at the quantities we require. Thus it is not easy
to measure the real thickness of a deposit. It may be folded
back upon itself, and so we may measure it twice over.
We may exaggerate its thickness by measuring it not quite
straight across the bedding or by unwittingly including volcanic
materials. On the other hand, there may be deposits which
are inaccessible to us ; or, again, an entire absence of de-
posits ; either because not laid down in the areas we examine,
or, if laid down, again washed into the sea. These sources
of error in part neutralise one another. Some make our
resulting age too long, others make it out too short. But
we do not know if a balance of error does not still remain.
Here, however, is a table of deposits which summarises a
great deal of our knowledge of the thickness of the strati-
graphical accumulations. It is due to Prof. Sollas. 1

Feet.

Recent and Pleistocene .... 4,000

Pliocene ....... 13,000

Miocene 14,000

Oligocene 12,000

Eocene 20,000

63,000

Upper Cretaceous 24,000

Lower „ 20,000

Jurassic . 8,000

Trias 17,000

69,000

Permian 12,000

Carboniferous ...... 29,000

Devonian 22,000

63,000

Silurian 15,000

Ordovician ....... 17,000

Cambrian 26,000

58,000

Keweenawan ~\ ..... 50,000

Animikian . > Algonkian .... 14,000
Huronian .J 18,000

82,000

Archaean ?

Total 335)°°° f eet -

1 Address to the Geol. Soc. of London, 1909.

THE BIRTH-TIME OF THE WORLD 41

In the next place we require to know the average rate at
which these rocks were laid down. This is really the weakest
link in the chain. The most diverse results have been
arrived at, which space does not permit us to consider.
The value required is most difficult to determine, for it is
different for the different classes of material, and varies from
river to river according to the conditions of discharge to
the sea. We may probably take it as between two and six
inches in a century.

Now the total depth of the sediments as we see is about
335,000 feet (or 64 miles), and if we take the rate of collecting
as 3 inches in a hundred years we get the time for all to
collect as 134 millions of years. If the rate be 4 inches, the
time is 100 millions of years, which is the figure Geikie
favoured, although his result was based on somewhat different
data. Sollas most recently finds 80 millions of years. 1

The Age by the Mass of the Sediments

In the above method we obtain our result by the measure-
ment of the linear dimensions of the sediments. These
measurements, as we have seen, are difficult to arrive at.
We may, however, proceed by measurements of the mass
of the sediments, and then the method becomes more definite.
The new method is pursued as follows :

The total mass of the sediments formed since denudation
began may be ascertained with comparative accuracy by a
study of the chemical composition of the waters of the ocean.
The salts in the ocean are undoubtedly derived from the
rocks ; increasing age by age as the latter are degraded from
their original character under the action of the weather, etc.,
and converted to the sedimentary form. By comparing the
average chemical composition of these two classes of material —
the primary or igneous rocks and the sedimentary — it is
easy to arrive at a knowledge of how much of this or that
constituent was given to the ocean by each ton of primary
rock which was denuded to the sedimentary form. This,
however, will not assist us to our object unless the ocean
has retained the salts shed into it. It has not generally done

1 Geikie, Text Book of Geology (Macmillan, 1903), vol. i. p. 73 et seq. Sollas,
loc. cit. Joly, Radioactivity and Geology (Constable, 1909), Phil. Mag. Sept,
.191 1.

42 SCIENCE PROGRESS

so. In the case of every substance but one only, the ocean
continually gives up again more or less of the salts supplied
to it by the rivers. The one exception is the element sodium.
The great solubility of its salts has protected it from abstraction,
and it has gone on collecting during geological time, practi-
cally in its entirety. This gives us the clue to the denudative
history of the earth. 1 It is the secret of the sea.

The process is now simple. We estimate by chemical
examination ol igneous and sedimentary rocks the amount of
sodium which has been supplied to the ocean per ton of
sediment produced by denudation. We also calculate the
amount of sodium contained in the ocean. We divide the
one into the other (stated, of course, in the same units of
mass), and the quotient gives us the number of tons of sedi-
ment. The most recent estimate of the sediments made in
this manner affords 56 x io 16 tonnes. 2

Now we are assured that all this sediment was transported
by the rivers to the sea during geological time. Thus it follows
that if we can estimate the average annual rate of the river
supply of sediments to the ocean over the past we can calculate
the required age. Now the land surface is at present largely
covered with the sedimentary rocks themselves. Sediment
derived from these rocks must be regarded as, for the most
part, purely cyclical ; that is, circulating from the sea to the
land and back again. It does not go to increase the great body
of detrital deposits. We cannot, therefore, take the present
river supply of sediment as representing that obtaining over
the long past. If the land was all covered still with primary
rocks we might do so. It has been estimated that about 25 per
cent of the existing continental area is covered with archaean
and igneous rocks, the remainder being sediments. 3 On this
estimate we may find valuable major and minor limits to the
geological age. If we take 25 per cent, only of the present
river supply of sediment, we evidently fix a major limit to the
age, for it is certain that over the past there must have been

1 Trans. R.D.S., May 1899.

2 Clarke, A Preliminary Study of Chemical Denudation (Washington 1910).
My own estimate in 1899 (loc. cit.) made as a test of yet another method of
finding the age, showed that the sediments may be taken as sufficient to form
a layer vi mile deep if spread uniformly over the continents ; and would amount
to 64 x io ,G tons.

3 Van Tillo, Comptes Rendues (Paris), vol. c.xiv. 1893-

THE BIRTH-TIME OF THE WORLD

on the average a faster supply. If we take the entire river
supply, on similar reasoning we have what is undoubtedly a
minor limit to the age.

The river supply of detrital sediment has not been very
extensively investigated, although the quantities involved may
be found with comparative ease and accuracy. The following
table embodies the results obtained for some of the leading
rivers. 1

Mean annual dis-
charge in cubic feet
per second.

Total annual sedi-
ment in thousands
of tons.

Ratio of sediment

to water by

weight.

Potomac .
Mississippi
Rio Grande
Uruguay .
Rhone
Po .

Danube .
Nile
Irrawaddy

20,l6o

6lO,000

1,700

I 50,000

65,850

62,200

315,200

1 1 3,000

475,000

5,557
406,250

3,$3°
14,782

36,000

67,000

108,000
54,000

291,430

3,575
1,500

291

10,000

1,775

900

2,880
2,050
1,610

Mean ....

201,468

109,650

i : 2,731

We see that the ratio of the weight of water to the weight
of transported sediment in six out of the nine rivers does not
vary widely. The mean is 2,730 to 1. But this is not the
required average. The water-discharge of each river has to
be taken into account. If we ascribe to the ratio given for
each river the weight proper to the amount of water it dis-
charges, the proportion of weight of water to weight of sediment,
for the whole quantity of water involved, comes out as 2,520 to 1.

Now if this proportion holds for all the rivers of the world —
which collectively discharge about 27 x io 12 tonnes of water
per annum — the river-born detritus is 1*07 x io 10 tonnes. To
this an addition of 1 1 per cent has to be made for silt pushed
along the river-bed. 2 On these figures the minor limit to the
age comes out as 47 millions of years, and the major limit as
188 millions. We are here going on rather deficient estimates,
the rivers involved representing only some 6 per cent of the
total river supply of water to the ocean. But the result is
probably not very far out.

1 Russell, River Deveiop?ne?it (John Murray, 1898).

2 According to observations made on the Mississippi (Russell, he. at.).

44 SCIENCE PROGRESS

We may arrive at a probable age lying between the major
and minor limits. If, first, we take the arithmetic mean of these
limits, we get 117 millions of years. Now this is almost cer-
tainly excessive, for we here assume that the rate of covering
of the primary rocks by sediments was uniform. It would not
be so, however, for the rate of supply of sediment must have
been continually diminishing during geological time, and hence
we may take it the rate of advance of the sediments on the
primary rocks has also been diminishing. The average rate
of supply has therefore been greater than the mean rate. Now
we may probably take, as a fair assumption, that the sediment-
covered area was at any instant increasing at a rate pro-
portionate to the rate of supply of sediment ; that is, to the area
of primary rocks then exposed. On this assumption the age
is found to be 8y millions of years.

The Age by the Sodium of the Ocean

I have next to lay before you a quite different method. I
have already touched upon the chemistry of the ocean, and on
the remarkable fact that the sodium contained in it has been
preserved, practically, in its entirety from the beginning of
geological time.

That the sea is one of the most beautiful and magnificent
sights in Nature all admit. But, I think, to those who know
its story its beauty and magnificence are ten-fold increased. Its
saltness is due to no magic mill. It is the dissolved rocks of
the earth which give it at once its brine, its strength, and its
buoyancy. The rivers which we say flow with "fresh" water
to the sea nevertheless contain those traces of salt which,
collected over the long ages, occasion the saltness of the ocean.
Each gallon of river water contributes to the final result ; and
this has been going on since the beginning of our era. Consider
the mighty total of the rivers : 6,500 cubic miles of water in the
year ! Yet vast as it is, how little in the overwhelming
magnitude of the ocean !

There is little doubt that the primeval ocean was in the
condition of a fresh-water lake. It can be shown that a primi-
tive and more rapid solution of the original crust of the earth
by the slowly cooling ocean would have given rise to relatively
small salinity. The fact is the quantity of salts in the ocean
is enormous. We are only now concerned with the sodium;

THE BIRTH-TIME OF THE WORLD 45

but if we could extract all the rock-salt (the chloride of sodium)
from the ocean we would have enough to cover the entire dry
land of the earth to a depth of 400 feet. It is this gigantic
quantity which is going to enter into our estimate of the earth's
age. The calculated mass of sodium contained in this rock-salt
is 14,130 million million tonnes.

If now we can determine the rate at which the rivers supply
sodium to the ocean, we can determine the age. 1 As the result
of many thousands of river analyses, the total amount of sodium
annually discharged to the ocean by all the rivers of the world
is found to be probably not far from 175 million tonnes. 2
Dividing this into the mass of oceanic sodium we get the age
as 807 millions of years. Certain corrections have to be applied
to this figure which result in raising it to a little over 90 millions
of years. By this method Sollas gets the age as between
80 and 150 millions of years. My own result 3 was between
80 and 90 millions of years ; but I subsequently found that upon
certain extreme assumptions a maximum age might be arrived
at of 105 millions of years. 4 Clarke regards the 807 millions of
years as certainly a maximum in the light of certain calculations
by Becker. 5

The order of magnitude of these results cannot be shaken

1 Trims. R.D.S. 1899. A paper by Edmund Halley, the astronomer, in the
Philosophical Transactions of the Royal Society for 171 5, contains a suggestion
for finding the age of the world on somewhat similar lines. He proposes to make
observations on the saltness of the seas and ocean at intervals of one or more
centuries, and from the increment of saltness arrive at their age. The measure-
ments, as a matter of fact, are impracticable. The salinity would only gain (if all
remained in solution) one millionth part in 100 years ; and, of course, the con-
tinuous rejection of salts by the ocean would invalidate the method. The last
objection also invalidates the calculation by T. Mellard Reade (Proc. Liverpool
Geol. Soc. 1876) of a minor limit to the age by the calcium sulphate in the ocean.
Both papers were quite unknown to me when working out my method. Halley's
paper was, I think, only brought to light in 1908.

* J. W. Clarke, A Preliminary Study of Chemical Denudation (Smithsonian
Miscellaneous Collections, 1910).

3 Loc. cit.

* "The Circulation of Salt and Geological Time" (Geol. Mag. 1901, p. 350).

5 Becker (loc. cit.), assuming that the exposed igneous and archcean rocks alone
are responsible for the supply of sodium to the ocean, arrives at 74 millions of
years as the geological age. This matter was discussed by me formerly (Trans.
R. D. S. 1899, pp. 54 et seq.). The assumption made is, I believe, quite inad-
missible. It is not supported by river analyses, or by the chemical character of
residual soils from sedimentary rocks. There may be some convergence in the rate
of solvent denudation, but -as I think on the evidence— in our time unimportant.

46 SCIENCE PROGRESS

unless on the assumption that there is something entirely mis-
leading in the existing rate of solvent denudation. On the
strength of the results of another and entirely different method
of approaching the question of the earth's age (which shall be
presently referred to), it has been contended that it is too low.
It is even asserted that it is from nine to fourteen times too low.
We have then to consider whether such an enormous error can
enter into the method. The measurements involved cannot be
seriously impugned. Corrections for possible errors applied
to the quantities entering into this method have been considered
by various writers. My own original corrections have been
generally confirmed. I think the only point left open for dis-
cussion is the principle of uniformitarianism involved in this
method and in the methods previously discussed.

In order to appreciate the force of the evidence for uni-
formity in the geological history of the earth, it is, of course,
necessary to possess an acquaintance with that history. Some
of the most eminent geologists, among whom Lyle and Geikie '
may be mentioned, have upheld the doctrine of uniformity. It
must here suffice to dwell upon a few points having special
reference to the matter under discussion.

The mere extent of the land surface does not, within limits,
affect the question of the rate of denudation. This arises from
the fact that the rain supply is quite insufficient to denude the
whole existing land surface. About 30 per cent of it does not,
in fact, drain to the ocean. If the continents become invaded
by a great transgression of the ocean, this " rainless " area
diminishes : and the denuded area advances inwards without
diminution. If the ocean recedes from the present strand
lines, the " rainless " area advances outwards, but, the rain
supply being sensibly constant, no change in the river supply of
salts is to be expected.

Age-long submergence of the entire land, or of any very
large proportion of what now exists, is negatived by the con-
tinuous sequence of vast areas of sediment in every geologic age
from the earliest times. Now sediment-receiving areas always
are but a small fraction of those exposed areas whence the sedi-
ments are supplied. 2 Hence in the continuous records of the

1 See especially Geikie's Address to Sect. C, Brit. Assoc. Rep. 1899.

2 On the strength ot the Mississippi measurements about 1 to 18 (Magee,
Am. Jour, of Sc. 1892, p. 188).

THE BIRTH-TIME OF THE WORLD 4 7

sediments we have assurance of the continuous exposure of the
continents above the ocean surface. The doctrine of the per-
manency of the continents has in its main features been accepted
by the most eminent authorities. As to the actual amount of
land which was exposed during past times to denudative effects,
no data exist to show it was very different from what is now
exposed. It has been estimated that the average area of the
North American continent over geologic time was about eight-
tenths of its existing area. 1 Restorations of other continents, so
far as they have been attempted, would not suggest any more
serious divergency one way or the other.

That climate in the oceans and upon the land was through-
out much as it is now, the continuous chain of teeming life and
the sensitive temperature limits of protoplasmic existence are
sufficient evidence. 2 The influence at once of climate and of
elevation of the land may be appraised at their true value by
the ascertained facts of solvent denudation, as the following table
shows.

Tonnes removed in M elevatiou

solution per square M

mile per annum.

North America . . . -79 700

South America . . . .50 650

Europe ...... 100 300

Asia 84 950

Africa 44 650

In this table the estimated number of tonnes of matter
in solution, which for every square mile of area the rivers
convey to the ocean in one year, is given in the first column.
These results are compiled by Clarke from a very large number
of analyses of river waters. The second column of the table
gives the mean heights in metres above sea level of the several
continents, as cited by Arrhenius. 3

Of all the denudation results given in the table, those relating
to North America and to Europe are far the most reliable.
Indeed these may be described as highly reliable, being founded
on some hundreds or thousands of analyses, many of which have
been systematically pursued through every season of the year.
These show that Europe with a mean altitude of less than half
that of North America sheds to the ocean 25 per cent, more

1 C. Schuchert, Bull. Geol. Soc. Am., vol. xx. 1910.

2 See also Poulton, Address to Sect. D., Brit. Assoc. Rep. 1896.

3 Lehrbuch der Kosmischen Physik, vol. i. p. 347.

48 SCIENCE PROGRESS

salts. Hence if it is true, as has been stated, that we now live
in a period of exceptionally high continental elevation, we must
infer that the average supply of salts to the ocean by the rivers
of the world is less than over the long past, and that, therefore,
our estimate of the age of the earth as already given is
excessive.

There is, however, one condition which will operate to
unduly diminish our estimate of geologic time, and it is a con-
dition which may possibly obtain at the present time. If the
land is, on the whole, now sinking relatively to the ocean level,
the denudation area tends, as we have seen, to move inwards.
It will thus encroach upon regions which have not for long
periods drained to the ocean. On such areas there is an
accumulation of soluble salts which the deficient rivers have
not been able to carry to the ocean. Thus the salt content of
certain of the rivers draining to the ocean will be influenced not
only by present denudative effects, but also by the stored results
of past effects. Certain rivers appear to reveal this unduly
increased salt supply : those which flow through comparatively
arid areas. However, the flow-off of such tributaries is relatively
small and the final effects on the great rivers apparently un-
important — a result which might have been anticipated when
the extremely slow rate of the land movements is taken into
account.

The difficulty of effecting any reconciliation of the methods
already described and that now to be given increases the interest
both of the former and the latter.

The Age by Radioactive Transformations

Rutherford suggested in 1905 that as helium was con-
tinually being evolved at a uniform rate by radioactive
substances (in the form of the alpha rays) a determination
of the age of minerals containing the radioactive elements
might be made by measurements of the amount of the stored
helium and of the radioactive elements giving rise to it. The
parent radioactive substance is — according to present know-
ledge — uranium or thorium. An estimate of the amounts of
these elements present enables the rate of production of the
helium to be calculated. Rutherford shortly afterwards found
by this method an age of 240 millions of years for a radioactive
mineral of presumably remote age. Strutt, who carried his

THE BIRTH-TIME OF THE WORLD 49

measurements to a wonderful degree of refinement, found the
following ages for mineral substances originating in different
geological ages :

Oligocene 8'4 millions of years.

Eocene 31 „ „ „

Lower Carboniferous . . .150 „ „ „

Archaean . . . . . .710 „ „ ,,

Periods of time much less than, and very inconsistent with,
these were also found. The lower results are, however, easily
explained if we assume that the helium — which is a gas under
prevailing conditions — escapes in many cases slowly from the
mineral.

Another product of radioactive origin is lead. The sugges-
tion that this substance might be made available to determine
the age of the earth also originated with Rutherford. We are
at least assured that this element cannot escape by gaseous
diffusion from the minerals. Boltwood's results on the amounts
of lead contained in minerals of various ages, taken in conjunc-
tion with the amount of uranium or parent substance present,
afforded ages rising to 1,640 millions of years for Archaean and
1,200 millions for Algonkian time. Becker, applying the same
method, obtained results rising to quite incredible periods : from
1,671 to 11,470 millions of years. Becker maintained that
original lead rendered the determinations indefinite. The more
recent results of Mr. A. Holmes support the conclusion that
" original " lead may be present and may completely falsify
results derived from minerals of low radioactivity in which the
derived lead would be small in amount. By rejecting such
results as appeared to be of this character, he arrives at
370 millions of years as the age of the Devonian.

I must now describe a very recent method of estimating the
age of the earth. There are, in certain rock-forming minerals,
colour-changes set up by radioactive effects. The minute and
curious marks so produced are known as haloes ; for they
surround, in ring-like forms, minute particles of included sub-
stances which contain radioactive elements. It is now well
known how these haloes are formed. The particle in the centre
of the halo contains uranium or thorium, and, necessarily, along
with the parent substance, the various elements derived from it.
In the process of transformation giving rise to these several
derived substances, atoms of helium, projected with great
4

S o SCIENCE PROGRESS

velocity into the surrounding mineral— the alpha rays — occasion
the colour changes referred to. These changes are limited to
the distance to which the alpha rays penetrate ; hence the halo
is a spherical volume surrounding the central substance. 1

The time required to form a halo can be found if on the one
hand we could ascertain the number of alpha rays ejected in,
say, one year from the nucleus of the halo, and, on the other, if
we determined by experiment just how many alpha rays were
required to produce the same amount of colour alteration as we
perceive to extend around the nucleus.

The latter estimate is fairly easily and surely made. But to
know the number of rays leaving the central particle in unit
time we require to know the quantity of radioactive material in
the nucleus. This cannot be directly determined. We can only,
from known results obtained with larger specimens of just such
a mineral substance as composes the nucleus, guess at the
amount of uranium, or it may be thorium, which may be present.

This method has been applied to the uranium haloes of the
mica of County Carlow. 2 Results for the age of the halo of from
20 to 400 millions of years have been obtained. This mica was
probably formed in the granite of Leinster in late Silurian or in
Devonian times.

The higher results are probably the least in error, upon the
data involved ; for the assumption made as to the amount of
uranium in the nuclei of the haloes was such as to render the
higher results the more reliable.

This method is, of course, a radioactive method, and similar
to the method by helium storage, save that it is free of the risk
of error by escape of the helium, the effects of which are, as it
were, registered at the moment of its production, so that its
subsequent escape is of no moment.

Review of the Results

We shall now briefly review the results on the geological age
of the earth.

By methods based on the approximate uniformity of denuda-
tive effects in the past, a period of the order of 100 millions of
years has been obtained as the duration of our geological age ;
and consistently whether we accept for measurement the sedi-

1 Phil. Mag, y March 1907 and February 1910; also Bedrock, January 1913.
1 Joly and Rutherford, Phil. Mag., April 1913.

THE BIRTH-TIME OF THE WORLD 51

ments or the dissolved sodium. We can give reasons why these
measurements might afford too great an age, but we can find
absolutely no good reason why they should give one much too low.

By the storage of radioactive products ages have been found
which, while they vary widely among themselves, yet claim to
possess accuracy in their superior limits, and exceed those
derived from denudation from nine to fourteen times.

In this difficulty let us consider the claims of the radioactive
method in any of its forms. In order to be trustworthy it must
be true : (1) that the rate of transformation now shown by the
parent substance has obtained throughout the entire past, and
(2) that there were no other radioactive substances, either now
or formerly existing, except uranium, which gave rise to lead.
As regards methods based on the production of helium, what
we have to say will largely apply to it also. If some unknown
source of these elements exists we, of course, on our assumption
over-estimate the age.

As regards the first point : In ascribing a constant rate of
change to the parent substance — which Becker (loc. cit.) describes
as " a simple though tremendous extrapolation " — we reason
upon analogy with the constant rate of decay observed in the
derived radioactive bodies. If uranium and thorium are really
primary elements, however, the analogy relied on may be mis-
leading ; at least, it is obviously incomplete. It is incomplete
in a particular which may be very important : the mode of
origin of these parent bodies — whatever it may have been — is
different to that of the secondary elements with which we com-
pare them. A convergence in their rate of transformation is
not impossible, or even improbable, so far as we know.

As regards the second point : It is assumed that uranium
alone of the elements in radioactive minerals is ultimately
transformed to lead by radioactive changes. We must consider
this assumption.

Recent advances in the chemistry of the radioactive elements
has brought out evidence that all three lines of radioactive descent
known to us — i.e. those beginning with uranium, with thorium,
and with actinium — alike converge to lead. 1 There are difficulties
in the way of believing that all the lead-like atoms so produced
(" isotopes " of lead, as Mr. Soddy proposes to call them) actually
remain as stable lead in the minerals. For one thins: there is

1 See Soddy's Chemistry of the Radioactive Elements (Longmans, Green & Co.).

52 SCIENCE PROGRESS

sometimes, along with very large amounts of thorium, an almost
entire absence of lead in thorianites and thorites. And in some
urano-thorites the lead may be noticed to follow the uranium
in approximate proportionality, notwithstanding the presence
of large amounts of thorium. 1 This is in favour of the assump-
tion that all the lead present is derived from the uranium. The
actinium is present in negligibly small amounts.

On the other hand, there is evidence arising from the atomic
weight of lead which seems to involve some other parent than
uranium. Mr. Soddy, in the work referred to, points this out.
The atomic weight of radium is well known, and uranium in
its descent has to change to this element. The loss of mass
between radium and uranium-derived lead can be accurately
estimated by the number of alpha rays given off. From this
we get the atomic weight of uranium-derived lead as closely 206.
Now the best determinations of the atomic weight of normal
lead assign to this element an atomic weight of closely 207. By
a somewhat similar calculation it is deduced that thorium-derived
lead would possess the atomic weight of 208. Thus normal
lead might be an admixture of uranium- and thorium-derived
lead. However, as we have seen, the view that thorium gives
rise to stable lead is beset with some difficulties.

If we are going upon reliable facts and figures, we must,
then, assume : (a) That some other element than uranium, and
genetically connected with it (probably as parent substance),
gives rise, or formerly gave rise, to lead of heavier atomic
weight than normal lead. It may be observed respecting
this theory that there is some support for the view that a
parent substance both to uranium and thorium has existed
or possibly exists. The evidence is found in the proportionality
frequently observed between the amounts of thorium and
uranium in the primary rocks. 2 Or : (b) We may meet the

1 It seems very difficult at present to suggest an end product for thorium, unless
we assume that, by loss of electrons, thorium E, or thorium-lead, reverts to a
substance chemically identical with thorium itself. Such a change— whether
considered from the point of view of the periodic law or of the radioactive theory —
would involve many interesting consequences. It is, of course, quite possible
that the nature of the conditions attending the deposition of the uranium ores,
many of which are comparatively recent, are responsible for the difficulties
observed. The thorium and uranium ores are, again, specially prone to alteration.

2 Compare results for the thorium content of such rocks (appearing in a
paper by the author Cong. Int. de Radiologic et d' 1 Electricity vol. i. 1910, p. 373)
and those for the radium content, as collected in Phil. Mag., October 1912, p. 697.

THE BIRTH-TIME OF THE WORLD 53

difficulties in a simpler way, which may be stated as follows :
If we assume that all lead is derived from uranium, and at the
same time recognise that lead is not perfectly homogeneous
in atomic weight, we must, of necessity, ascribe to uranium a
similar want of homogeneity; heavy atoms of uranium giving
rise to heavy atoms of lead and light atoms of uranium gene-
rating light atoms of lead. This assumption seems to be
involved in the figures upon which we are going. Still
relying on these figures, we find, however, that existing
uranium cannot give rise to lead of normal atomic weight.
We can only conclude that the heavier atoms of uranium have
decayed more rapidly than the lighter ones. In this connection
it is of interest to note the complexity of uranium as recently
established by Geiger, although in this case it is assumed that
the shorter-lived isotope is genetically connected with the
longer-lived and largely preponderating constituent. There
does not seem to be any direct proof of this as yet, however.

From these considerations it would seem that unless the
atomic weight of lead in uraninites, etc, is sub-normal, the
former complexity and more accelerated decay of uranium
are involved in the data respecting the atomic weights of
radium and lead and the radioactive events which occur in
the transmutation of the one into the other. As an alternative
view, we may assume, as in our first hypothesis, that some
elementally different but genetically connected substance, de-
caying along branching lines of descent at a rate sufficient
to practically remove the whole of it during geological time,
formerly existed. Whichever hypothesis we adopt we are con-
fronted by probabilities which invalidate time-measurements
based on the lead and helium ratio in minerals. We have, in
short, grave reason to question the measure of uniformitarianism
postulated in finding the age by any of the known radio-
active methods.

That we have much to learn respecting our assumptions,
whether we pursue the geological or the radioactive methods
of approaching the age of our era, is, indeed, probable. What-
ever the issue it is certain that the reconciling facts will leave
us with much more light than we at present possess either as
respects the earth's history or the history of the radioactive
elements. With this necessary admission we leave our study
of the Birth-Time of the World.

54 SCIENCE PROGRESS

It has led us a long way from Lucretius. We do not ask
if other Iliads have perished ; or if poets before Homer
have vainly sung, becoming a prey to all-consuming time. We
move in a greater history, the land-marks of which are not
the birth and death of kings and poets, but of species, genera,
orders. And we set out these organic events not according
to the passing generations of man, but over hundreds or
thousands of millions of years.

How much Lucretius has lost, and how much we have
gained, is bound up with the question of the intrinsic value
of knowledge and great ideas. Let us appraise knowledge
as we would the Homeric poems, as something which ennobles
life and makes it happier. Well, then, we are, as I think, in
possession to-day of some of those lost Iliads and Odysseys
for which Lucretius looked in vain.

SEA-SALT AND GEOLOGIC TIME

By H. S. SHELTON, B.Sc.

The present short article is a reversion to an aspect of the
subject of geologic time which I had thought to be settled,
and to require no further research or controversy. In my
review of Mr. Holmes's book ! I commented strongly on his
ignorance of current literature. I now find that the same
imperfect acquaintance with recent discussion and research is
shared by the writer who is responsible for putting forward the
amount of sodium in the sea as an index of geologic time. I
assume, of course, that ignorance is the explanation, for I take it
that no man of science of recognised position, when the errors of
his research had been pointed out, would deliberately ignore the
fact, and proceed as if his work was a valid contribution to the
advancement of science. My excuse, therefore, for writing an
article containing nothing material which I have not previously
published is the following passage, for which Sir Ernest
Rutherford and Prof. Joly are jointly responsible :

11 But it is certain that, if the higher values so found are
reliable, the discrepancy with estimates of the age of the ocean,
based on the now well-ascertained facts of solent denudation,
raises difficulties which at present seem inexplicable." 2

The values of geologic time referred to, based on radioactive
methods, especially the age of pleochroic haloes, I propose to
criticise on a future occasion. There are good grounds, which
cannot be stated here, for thinking that all attempts to assess
exact times for particular geologic epochs by calculation either
of the lead ratios of uranium minerals or otherwise are prema-
ture, and are based on an imperfect realisation of the complexity
of the subject. The object of the present article, however, is to
repeat 3 the arguments which show that the alternative method
based on the salt-content of the ocean is of no value whatever.

1 This journal, July 1913.

2 Philosophical Magazine, May 1913, p. 657.

3 The previous statements are: Journal of Geology, Feb. -March 1910 ; Con-
temporary Review, Feb. 191 1.

56 SCIENCE PROGRESS

Not only is the discrepancy not inexplicable, there is no dis-
crepancy to explain. So much did I take this for granted that,
in my last article on the subject, 1 I did not think it necessary to
consider the sea-salt method. I therefore take this opportunity
to repeat the arguments, and to remedy what is apparently a
deficiency.

Prof. Joly's original paper 2 was based on the supposed facts
(i) that, as roughly estimated by Sir John Murray, of the solid
matter dissolved in river water which reaches the sea 3*47
per cent, is sodium ; (2) that nearly all this, hypothetical sodium is
obtained by erosion of the rocks ; (3) that when this hypothetical
sodium reaches the sea, none of it returns to the rocks. On this
supposition, dividing the amount of sodium in the sea by the
amount which reaches it each year, an estimate of geologic time
could be made. The objection is, briefly, that the three
supposed facts are merely supposed facts. No single one of
them is reliable.

For convenience we will take the second point first. Of the
sodium which actually reaches the sea, a considerable pro-
portion is associated with chlorine. None of the sodium chloride
in the rivers can be attributed to erosion. This is so for two
reasons. In the first place, it is well known that the proportion
of chlorine in the rocks, igneous or sedimentary, is infinitesimal.
In the second place, the sources of the chlorine have been
thoroughly well determined. In the main, they are two, cyclic
salt, carried by the wind from the sea, and salt due to human
contamination. It has been found possible, particularly in New
York State, to eliminate the cyclic salt, the amount of which is a
function of the distance from the coast, and to show that the
residual chlorine in river water is a direct function of density of
population. Unless you take the sewage from town and country
districts directly out to sea, the salt in it inevitably reaches the
rivers. If you obtain an abnormally high chlorine ratio when
the sewage is supposed to be carried out to sea, the inference is
leakage. The source which would naturally occur to any one,
brine-springs, has been shown to be negligible. Even in New

1 This journal, Oct. 1913.

2 Trans. Royal Society, Dublin, vol. 7, pp. 26f. Sir John Murray's paper, Scottish
Geographical Magazine, 1887. The results are best tabulated for the purposes of
this discussion in the " Data of Geochemistry," U.S.A. Geological Survey Bulletin
No. 330, p. 88.

SEA-SALT AND GEOLOGIC TIME 57

York State, where brine-springs are plentiful, there is no
appreciable effect on the salt content of the rivers. 1 The only
known means by which fresh chlorine reaches the sea is volcanic
action, and it is a point open to dispute how much of the volcanic
chlorine is not ultimately derived from the sea. It follows,
therefore, that, of the sodium which actually reaches the sea,
only that not associated with the chlorine can be counted.

This much Prof. Joly and those who agree with his earlier

estimate have been willing to admit. But Prof. Joly maintains

that, if the chlorine equivalent of the sodium be subtracted,

there is still sufficient sodium to necessitate an estimate of

geologic time less than 150 millions of years. His reason is

merely Sir John Murray's rough tabulation of then current

analyses and some more recent results. It does seem strange,

however, that Prof. Joly never troubled to inquire whether there

were any water analyses sufficiently accurate for his purpose.

It is highly probable that Prof. Joly's original paper would

never have been written if he had understood why water

analyses are undertaken, and the manner in which they are

actually performed. Had he been a water analyst, or even a

chemist, the first thing that would have occurred to him would

have been that these sodium determinations were decidedly

hypothetical. Several chemists have expressed doubts as to the

validity, but such discussions Prof. Joly has either ignored or

failed to understand. 2 It may, therefore, surprise Prof. Joly

to be informed that it is doubtful whether the sodium content of

any single river water has ever been accurately determined. If

any such cases have occurred, they are very few. Let us

imagine that there is, in a given sample of river water, two

parts of sodium per million. Such a proportion would be quite

ordinary according to the usual tables. It would be a very

interesting problem to try to separate this out and weigh it. To

obtain a good weighable quantity (say '05 gram of sodium giving

about *i 5 gram of sodium sulphate 3 ) would require 25 litres of

1 For further information on these points see Jackson's " Normal Distribution
of Chlorine," U.S.A. Geological Survey, Water Supply Paper No. 144.

2 See particularly discussion with Mr. Acroyd, Chemical News, 1901, and F. W.
Clarke, Data of Geochemistry, p. no.

3 In ordinary accurate analysis sodium is usually weighed as sulphate. In
water analysis, however, the quantity is so small that conversion to sulphate is not
worth while. The residue is reckoned as chloride, though it need not necessarily
be so.

58 SCIENCE PROGRESS

water, the greater part of a carboy, and the difficulties in the
way of isolating it are such as any chemist -can understand.

As a matter of fact, the accurate determination of the sodium
is a form of amusement in which the ordinary water analysts do
not indulge. Sometimes the alkalis sodium and potassium are
determined together by difference, that is, not determined at all.
In a paper 1 that has been sent to me recently the analyst
describes his methods. In this case, everything possible is got
rid of by the usual methods of precipitation, and the remainder
is evaporated and weighed as "Sodium and Potassium Chlorides."
The amount dealt with is only that from 250 cc. of filtered
water, and would, of course, be infinitesimal, and the fact that it
amounts to not more than 2 or 3 per cent, of the total dissolved
solid is a good indication of the general accuracy of the analysis.
The residue includes, of course, everything that is not caught by
the filter throughout the whole operation. It should be men-
tioned, also, that the samples usually stand for days in glass
bottles. In such cases of water analysis when the sodium and
the potassium are separated, the separation is, needless to say,
a very approximate operation. 2

It is no reflection on the accuracy of river water analysts to
say that the results are of no value whatever for Prof. Joly's
purpose. No one, except Prof. Joly and a few geologists, wants
to know the proportion of sodium in river water. It is at the
same time the constituent least important for the purposes of
the water analyst and the constituent most difficult to determine.
The assumption on which Prof. Joly proceeds, that 347 per cent,
of the dissolved matter in river water is sodium, is absolutely
unproven. For all the analyses prove, it might be less than half
that amount. Indeed the principal evidence that there is an
excess of sodium over and above its equivalent of chlorine is
indirect rather than direct. The results of rock analyses are
more reliable and it seems to be established that the sodium
content of igneous rocks is greater than that of the aqueous.
As a matter of fact it has been pointed out by Prof. Dubois that,

1 "The Quality of the Surface Waters of Illinois," U.S.A. Geological Survey,
Water Supply Paper No. 239, p. 16. The method is the one usually recom-
mended in the text-books. See Wanklyn, nth edition, p. 122.

- The potassium determination would be the more accurate of the two, as the
potassium is weighed as Pt. + 2KCI. A further percentage of inaccuracy would
thus be thrown on the sodium.

SEA-SALT AND GEOLOGIC TIME 59

when there is any reason to ascribe special accuracy to river-
water analysis, the excess of sodium diminishes and tends to
vanish. Prof. Dubois 1 collected a number of good analyses,
tabulated them, and inferred from them, according to Prof. Joly's
method, a geologic time of 400 millions of years. The inference
he made, as he was a believer in Lord Kelvin's methods, was
that the original sea was salt. The true inference is that the
method is of no value. Within the limits of experimental error
you can deduce any value you please.

Though the previous discussion renders it unnecessary, it
is as well to mention one other point. The assumption that no
sodium returns from the sea to the rocks is unwarranted.
Indeed one instance to the contrary can be mentioned. It is a
recognised fact that much of the salt in the salt lakes, and
inferentially in salt beds, is windborne and has its origin in the
sea. But what would occur when strata containing salt beds
are subject to metamorphosis or are absorbed by the magna?
Is it not obvious that the sodium would be added to the content
of the rocks and that the chlorine would be expelled as some
volatile compound ? Indeed, is it not probable that some
portion of volcanic chlorine has this origin ? Again, with regard
to the ordinary processes of the formation of sedimentary rock,
we do not know enough to say that no dissolved sodium is
reabsorbed.

This speculation, however, is a side-issue, and is not neces-
sary to the argument. Were the analyses of sufficient accuracy,
were the method in general valid, such matters would require
careful consideration. At present, without taking such remote
speculations into account, we can still say that the sea-salt method
is absolutely worthless. It is based on a misapprehension ol
the data on which it rests. It is an instance of the care that is
required when results are transferred from one branch of science
to another. With regard to geologic time, the value of radio-
active methods is still to be determined. The value of the sea-
salt method, like the still more famous ones of Kelvin and Tait,
is nil.

1 Proceedings Amsterdam Academy, 1904.

A REVIEW OF IGNEOUS ROCK CLASSI-
FICATION

By G. W. TYRRELL, A.R.C.Sc, F.G.S.
Lecturer in Mineralogy and Petrology, Glasgow University

The recent publication of the second volume of Prof. J. P.
Iddings' great work on Igneous Rocks (Description and Occur-
rence) marks an epoch in the history of petrological science. It
is a gallant attempt to infuse the quantitative spirit into the dry
bones of the older and laxer system of igneous rock classifica-
tion, and also to correlate the Quantitative Classification invented
by Iddings, in collaboration with Cross, Pirsson, and Washing-
ton, with the older qualitative system. In the writer's opinion,
it is a failure in the sense that it fails to reconcile irreconcilables,
but it is a great failure which will do much to turn the mental
outlook of petrographers from the comparatively barren qualita-
tive past to the hopeful and fruitful quantitative future.

In view of the publication of this work, the present seems an
appropriate time to re-examine the American Quantitative Classi-
fication and other classifications from a point of view frankly
sympathetic to the quantitative idea. It may be taken that all
petrologists are now more or less familiar with the main lines of
the American Quantitative Classification, and it is therefore
unnecessary to describe the system in detail. Many petrologists
have used it as an auxiliary to older methods of classification,
but none, so far as I am aware, have altogether dispensed with
the latter. The persistence and vigour of the qualitative system
at the present time, although the American Quantitative Classi-
fication has now had ten years for its trial, requires further
explanation than the inherent conservatism of petrographers.
In the writer's opinion, the Quantitative Classification has not
displaced the older system because it does not provide a ready
means of classification for the working petrographer. The
chemical analysis is the unit of the system, and it is only possible
for the petrographer to obtain analyses of a small proportion of
the rocks he describes. The greater part of his work deals with
the actual mineral composition or mode, and the classification

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 61

immediate to his needs must therefore be based on the mode,
and not on the norm (theoretical mineral composition) derivable
only from a chemical analysis or from determinations equivalent
to chemical analysis.

This view does not necessitate the abandonment of the
American Quantitative Classification. The latter provides a
final court of appeal for cases in which the mode is indecisive or
indeterminate. It is, so to speak, a regularly-reticulated back-
ground on which we may trace the magmatic characters of the
rocks ; or, to change the figure, it is a more or less convenient
system of pigeon-holing by which we may docket our rocks
according to their magmatic characters.

The advantages conferred by the American Quantitative
Classification and its authors on petrological science are many
and various. They exposed the lax, unsystematic character of
the older qualitative classification, and the chaotic condition
of its nomenclature. They forced a quantitative view-point
on petrographers and showed that the comparative method
in petrology was almost impossible under the qualitative
regime. Their criticisms have effected an immense improve-
ment in the technique of rock-analysis, and it is safe to predict
that in any new collection of rock-analyses the proportion of
" superior" to "inferior" examples will be much greater than in
those already published. They have insisted on the importance
of the chemical analysis from a petrological point of view, and
have raised its status from a mere ornamental but usually in-
accurate adjunct to petrological work to that of an essential and
indispensable part. The recognition of this changed status is
the probable cause for the great increase in the number of
analyses of igneous rocks now made. Furthermore, the exact,
detailed, and systematic methods of the authors of the American
Quantitative Classification have caused a great improvement in
descriptive work. Only of late years has it become possible
strictly to compare rocks from the ends of the earth simply
from their published descriptions ; and for this most desirable
consummation the more exact and detailed mineralogical and
textural description, and the publication of modal proportions,
insisted upon by the authors of the Quantitative Classification,
have undoubtedly been largely responsible. Finally, they have
given petrographers an instrument of inestimable value in the
conception of the norm.

62 SCIENCE PROGRESS

The American Quantitative Classification starts from the
hypothesis that there are no "natural" lines of division in
igneous rocks on which a classification may be based; that
igneous rocks constitute a continuous field in all directions, and
are only capable of an arbitrary division into compartments of
equal value, just as, for example, is the scale of temperature. 1
Dr. Cross's discussion of the adequacy of certain factors as a
basis for classification on " natural lines" seems to me conclusive
that there are no suitable factors save, perhaps, two. 2 The
factors of geographic distribution, magmatic differentiation,
eutectics, mineral composition and texture, are passed in review
and dismissed as affording no suitable " natural " basis for rock-
classification. The chemical composition, however, is treated as
the most fundamental character of igneous rocks, and as the one
most susceptible of arbitrary subdivision. The American Quan-
titative Classification has therefore been based on chemical com-
position so manipulated as to give a mineralogical expression.
The authors of this classification have never, in the writer's
opinion, given sufficient weight to the possibilities of a classifica-
tion by actual mineral composition, or, in other words, a modal
classification on quantitative lines. It is to be admitted that the
presence of minutely-crystallised or uncrystallised matter, and
the occupation of certain minerals in others, are grave difficul-
ties ; but these could probably be overcome by certain expedients
of which an outline is given later. In any case, the difficulties
so caused would probably not be so great as those caused by the
omission of the alferric minerals, for example, from the norm on
which the American Quantitative Classification is based.

From the standpoint of a utilitarian classification it is
certainly better to accept the American view of igneous rocks as
a "continuous series of chemical solutions and their solidified
phases " rather than continue to apply " the misleading bio-
logical concepts of ' families ' and ' descent ' " ; although it must
be admitted that many of the solidified solutions are related by
processes of differentiation from a common magma, and that
there may be a concentration of rock-types in certain parts of
the classificatory field.

1 Quantitative Classification of Igneous Rocks, by W. Cross, J. P. Iddings, L. V.
Pirsson, and H. S. Washington. Chicago, 1903.

'The Natural Classification of Igneous Rocks," Quart. Jour. Geo/. Soc. lxvi.
iyio, pp. 470-506.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 63

However manipulated, the chemical analysis is the unit dealt
with in the American Quantitative Classification. The analysis
of an igneous rock is first calculated into a set of standard
minerals (the norm), under fixed rules which, it is generally
admitted, follow and succinctly express most of the laws of
mineral formation in igneous magmas as we know them.
Certain important rock-forming minerals (the alferric — augite,
hornblende, biotite, muscovite, etc.) are not utilised in the norm
because of their complex chemical composition, although they
may actually be present in the rock. They are split up and
their components distributed to the normative minerals. The
norm is therefore a possible mode of crystallisation of all
magmas under certain conditions. Thereafter the classification
proceeds by taking factors from the norm two at a time, and
applying them consistently throughout (with one exception
explained later). It follows that the American Quantitative
Classification is a classification of chemical analyses or magmas,
not of the actual rocks. It is in effect a normative classification,
as contrasted with the modal classification which is forced on
the working petrographer by the sheer impossibility of obtaining
chemical analyses of all the rocks he wishes to describe. 1

The norm is first divided into salic (quartz, felspars, fels-
pathoids) and femic (pyroxenes, olivine, ores, etc.) groups,
whose relative proportions furnish the first line of subdivision
into Classes. Five Classes, bounded strictly by arithmetical
ratios between the salic and femic groups, are thus formed, and
express quantitatively Brogger's division of igneous rocks into
leucocratic and melanocratic phases ; not, as stated by Cross,
the old subdivision into acid, subacid, sub-basic, basic, and
ultrabasic. The first three Classes are then each divided into
nine Orders on the basis of the ratios of normative quartz or
lenads (felspathoids) to the felspars present. This really ex-
presses the variations of rocks in respect to the ratio between
alkalis and silica. Assuming the ferromagnesian minerals and
anorthite to have their necessary quota of silica, the presence
of quartz or felspathoid in a rock depends on whether the
remaining silica does or does not exceed that necessary to the
formation of alkali-felspar. The latter may be independent, or

1 The utility of the norm is unquestionable. As an instrument for comparing
rocks, especially those it is impossible to compare modally, it is of great value, as
well as for other purposes.

64 SCIENCE PROGRESS

in combination with anorthite as a mixed felspar. Classes IV.
and V. are divided into Orders on the basis of certain ratios
between the femic minerals, an arrangement criticised later in
this paper.

The Orders in Classes I., II., and III. are subdivided into five
arithmetically bounded compartments, called rangs, based on
the molecular proportions of potash and soda as against lime in
the salic minerals ; that is, on the ratio between alkali-felspars
plus lenads to anorthite. The rangs therefore quantitatively
express the relations between alkali-felspars plus felspathoids to
anorthite felspar in igneous rocks, less accurately the relation
between alkali-felspars and felspathoids to plagioclase felspar.
They give a quantitative expression to the conception of
"alkalic" and "calcic" types amongst igneous rocks. The
rangs are further subdivided, on the same five-fold basis, into
compartments called subrangs, according to the ratio between
the salic potash and soda. The subrangs therefore express the
quantitative relations between orthoclase and leucite on the one
hand, to albite and nepheline on the other — that is, between the
potassic and sodic constituents of magmas. Subdivision of the
subrangs is made into grads which depend on ratios subsisting
between the subordinate femic minerals. The grads have been
very seldom used.

In Classes IV. and V. the orders, sections of orders, rangs,
and subrangs are based on certain ratios subsisting between the
predominant femic constituents, which it is not necessary to
particularise here. Further subdivision into grads is based
upon the proportions obtaining among the subordinate salic
minerals.

Other refinements of classification are also to be found in the
system, as, for example, the formation of sub-classes in Classes
I., II. and III. for the reception of rocks rich in corundum,
zircon, etc.

Many criticisms of this classification have been made. The
commonest, perhaps, is that it is " arbitrary," " unnatural," " a
priori," and constructed without regard to the possible discovery
of a " natural " mode of classification. This is the gist of
Harker's unsparing criticism. 1 In answer C.I.P.W. 2 admit that

1 Natural History of Igneous Rocks, 1909, pp. 362-6.

2 A convenient contraction for the names of the authors of the Quantitative
Classification — Cross, Iddings, Pirsson, and Washington.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 65

the system is arbitrary, but that it is necessarily so since
igneous rocks are insusceptible to a quantitative treatment on
any " natural" or genetic factor as yet discovered, and constitute
a uniform field in all directions, only capable of arbitrary sub-
division into compartments of equal value. The discussion thus
shifts to the question of the possibility of a " natural " quantitative
classification expressing the genetic relations of igneous rocks.
As the result of a rigorous discussion, Dr. Cross concludes that
a natural basis for classification, whilst desirable, is impossible
in view of the unsuitability of most of the factors proposed. 1
It must also be admitted that at present no suitable factors
for quantitative treatment have emerged, save chemical and
mineralogical composition, and that it is highly improbable any
further " natural " basis for classification will be discovered in
the future. But since the needs of petrographers are immediate,
it appears necessary to fall back on an arbitrary mode of classi-
fication, even if only for purposes of reference and comparison. 2
Apart from the question as to whether there are any natural
bases for classification, petrographers cannot afford to wait for
their discovery. In the meantime, for want of an exact classi-
fication by which rocks may be compared, the science of com-
parative petrology, and the consideration of such important
problems as that of petrographic provinces, may come to a
standstill. It is of the utmost importance, therefore, to come to
a decision on this question of classification, if only from the
utilitarian point of view.

Another class of criticism of the American Quantitative
Classification is that which centres round the norm and its use
in the system. The norm is a set of standard minerals calculated
from the analysis of a rock, and has been criticised as " hypo-
thetical," "artificially selected," "ideal," even as "imaginary."
To this Dr. Cross replies that the minerals of the norm are
largely those which are believed by most petrographers to be
present as definite compounds in the magma, and which singly,
or variously combined, form the minerals actually present in
the rock. There is, however, some point in the criticism, since
petrographers have to deal with rocks composed of minerals,
and not with magmatic molecules which are necessarily some-
what hypothetical. Dr. Cross also points out that the norm

1 Quart. Jour. Geo/. Soc. vol. 66, 1910, pp. 470-506.

- J. W. Evans, in discussion of Cross's paper, ibid. p. 504.

66 SCIENCE PROGRESS

" is primarily a means of comparison, and has in itself nothing
to do with system." 1 Many petrographers have found it
extremely useful for this and other purposes, quite apart from
classification.

The mode of calculation of the norm has received very little
criticism save that of Evans. In the main it corresponds with
the well-understood principles of the crystallisation of minerals
from igneous magmas. Evans considers the operation of
calculating the norm instructive but unreal, and as not com-
paring in educative value with that of calculating the mode.
He also points out the undue influence of the amount of alumina
and the state of oxidation of the iron on the result of the
calculation. In fact the bulk of Evans's criticism is that the
mode of calculation and subsequent subdivision of the norm
causes certain constituents to have an undue effect on the
classification, and therefore that " the lines of division of the
Quantitative Classification do not stand in any logical relation
to the chemical composition." 2

Other criticism concerns the selection of certain minerals to
form the " salic " and " femic " groups of the norm. Evans
believes that " the salic group [is] in fact a collection of minerals
which [have] nothing essential in common, and that the funda-
mental lines of the classification [are] accordingly practically
meaningless." He instances especially the cases of corundum
and anorthite. In the calculation of the norm the excess of
alumina over that necessary for the formation of normative
felspars and felspathoids is regarded as corundum and placed
in the salic group. Generally, however, this excess enters
pyroxenes, amphiboles, or micas, and should thus be regarded
as femic. Anorthite, too, is considered as a basic silicate which
should enter the femic group, in spite of the fact that it generally
occurs in isomorphous admixture with albite. Nevertheless,
the division of the norm into salic and femic groups expresses
a common variation in igneous rocks which gives rise to what
are known as leucocratic and melanocratic facies. It is doubt-
ful, however, whether this factor should be given first place, as
it is in the American Quantitative Classification.

A further line of criticism is that the Quantitative Classifica-
tion does not fulfil its declared purpose of bringing like rocks

1 Quart. Jour. Ceol, Soc. vol. 66, 1910, p. 496.

2 Science Progress, vol. i. 1907, p. 275,

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 67

together. It is pointed out that even the subrangs contain a
great diversity of rocks, exhibiting" wide variations in almost
every constituent, and that the qualitative nomenclature is
correspondingly varied. The latter is in part due to " the
indefiniteness, confusion, and redundancy of modern nomencla-
ture," as shown by C.I.P.W., and admitted by Evans; partly to
the inclusion of all rocks chemically belonging to the subrang
whatever their texture, which is an important factor in qualita-
tive nomenclature. The wide variations in chemical composition,
however, are considered by Evans to be due to defects in the
classification brought about by the mode of calculation and the
subdivision of the norm. Such variations are inherent and
inevitable in any classification on a quantitative basis, even in
the smaller compartments. The compartments of similar size
in the qualitative classifications (such as Hatch's) probably
contain an even wider range of rocks. It is to be remarked,
however, that the method of the Quantitative Classification does
not admit of overlapping between the various compartments,
and that each compartment contains rocks differing from those
of any other.

In the investigation of an abnormal manganiferous series of
igneous rocks from India, Dr. L. L. Fermor found the Quantita-
tive Classification to lack the elasticity necessary to accommodate
the series, whilst he found it quite easy to fit it into Hatch's
classification. This, however, is very natural, since Hatch's
classes are based on silica percentage and are extremely com-
prehensive. The wider the compartments of a system, the easier
it is to place a given rock.

The type of Fermor's kodurite series is a phaneric rock
consisting of orthoclase, a manganese garnet (spandite), and
apatite, and is the basic member of a series of differentiated
igneous rocks ranging in acidity from quartz-orthoclase rocks,
through intermediate quartz-kodurites and basic kodurites, to
manganese-pyroxenites and garnet-rocks. The manganese
content in the analysed rocks of this series ranges from 10*50
to o'98, and in the typical kodurite is 9*08. The calculation of
the norms of these rocks presented some difficulty, which was
got over by introducing tephroite (manganese-olivine) as one
of the normative molecules. Fermor then shows that the
manganese, although fourth in importance in the chemical
analysis, and third in the norm, does not affect the classification

68 SCIENCE PROGRESS

until the ninth subdivision (section of subsection of section of
subgrad !) is reached. Moreover the two kodurites analysed
fall into different rangs, andase and monzonase, which depend
on the ratio of salic alkalis to salic lime ; whereas the chief
difference between the two rocks depends on the composition
of their respective garnets. Fermor therefore concludes 1 that the
American Quantitative Classification fails in one instance at
least to exhibit the elasticity which is claimed as an advantage
of the system. He infers that unusual amounts of other rare
constituents, such as baryta, strontia, nickel oxide, etc., would
also affect the system adversely. It is to be remarked, how-
ever, that a factor (such as MnO) which is of very minor
importance in the vast majority of igneous rocks, should also
be of minor importance in classification, notwithstanding its
occasional abundance in an abnormal and rare series of rocks.
Essentially Fermor demands that a classificatory factor should
vary in importance according to its significance in the rocks
which it is proposed to classify. But no consistent logical
classification could be erected on such a basis. Classification
must be based on the factors dominant, in significance and most
frequently also in mass, in the whole series of igneous rocks ;
and it is these factors which are used in the American
Quantitative Classification, and which will have to be used in
some form or other in all quantitative systems.

The American Quantitative Classification itself is not ex-
empt from a similar error ; and to this is due an asymmetry
of the system which does not yet appear to have been pointed
out. I refer to the radically different method of forming the
orders in Classes IV. and V., as compared with Classes I., II.,
and III. In the latter the orders are based on the ratios of
quartz or lenads to felspars ; in the former on the ratios of
pyroxenes plus olivine to the mitic minerals (magnetite,
ilmenite, haematite, titanite, etc.). This introduces a most con-
fusing break between Classes III. and IV., renders the com-
partments incommensurate on either side of the partition, and
makes the; tracing of a petrographic series from Classes I., II.,
and III. into Classes IV. and V. almost impossible. Employing
the figures already utilised, the pigeon-holes in Classes I., II.,

1 L. L. Fermor, "The Systematic Position of the Kodurite Series, especially
with reference to the Quantitative Classification," Records Geo/. Surv. India, xlii.
1912, p. 210.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 69

and III. are of the same size and shape, and are built of the
same material ; those in Classes IV. and V. are of entirely
different size and shape, and are built of different material.
Or three-fifths of our reticulated background is drawn to the
same pattern ; two-fifths to an entirely different pattern.

The reason for changing the basis of the orders is that
quartz, lenads, and felspars cease to be the dominant minerals
in Classes IV. and V., and give place to pyroxenes, olivines,
etc. The change, however, not only transgresses the principle
that a single pair of factors should be applied consistently
throughout, but also the principle that classification should be
based throughout on factors which are dominant in the whole
series of igneous rocks. It can hardly be denied that the
salic (or felsic) minerals are by far the most abundant and
significant constituents when the whole field of igneous rocks
is considered. Taking the general mean of all analyses of
igneous rocks as calculated by Clarke, 1 and as recalculated
by Cross into the norms, 2 we find that the four salic con-
stituents total 79 per cent., and the femic 21 per cent. If the
bulk of the various igneous rocks were taken into account it
is possible that the ratio of salic to femic constituents would
be still higher. 3 The primary factors in the classification there-
fore should be the salic ratios, and the femic ratios should
only be used after the salic are exhausted.

The convenience, simplicity, and correctness of using the
salic ratios right through the Quantitative Classification can be
shown by the consideration of some petrographic series which
traverse the partition between Classes III. and IV. The
magmatic symbols invented by C.I.P.W. are found very useful
in this connection. The subrang salemose, for example, is
represented by the symbol II. 6.3.4., indicating that a rock
in salemose falls into Class II. (dosalic), Order 6 (lendofelic),
Rang 3 (alkalicalcic), and Subrang 4 (dosodic), and thus has
a definite magmatic character. The persistence of some of
these numbers, or their sympathetic or antipathetic variation
one with the other, in the symbols of a related series of rocks,
indicates the persistence or regular variation of certain magmatic
characters. The consanguinity of the members of certain

1 "Some Geochemical Statistics," Proc. Amer. Phil. Soc. xli. 1912, pp. 214-34.

- Jour. Geol. xx. 191 2, p. 759.

3 Mennell. Geol. Mag. 1904, p. 263 ; 1909, p. 212.

SCIENCE PROGRESS

petrographic series may be admirably illustrated in this way,
as is seen in the lists given below, which are compiled from
tables in Iddings' Igneous Rocks, vol. ii. These series have
been selected from small and isolated areas, so as to ensure,
as far as possible, that the rocks belong to a related petro-
graphic series, and that there has been no admixture of rocks
of different ages.

Reunion Island (Iddings, pp. 589-90)

Phonolitic Trachyte l .

Phonolitic Trachyte .

Quartz-regirite-syenite

Akerite

Olivine -trachyandesite

Ophitic Basalt

Basalt .

Essexitic Gabbro

Gabbro

Basalt .

Olivine gabbro .

Felspathic picrite

Basalt .

Harrisite

r.5.1/4.
175.2.4.
(I)II.4'.i-3(4).
(1)11.5.2.4-

II. 5.2.4.

ir.5.3.4.

11(111)5.4.4.

(II)III.'5-3'4-

III.5.44'.
III.5/4.4.

III'.5-4(5).'5.
'IV.i'. 4 .i'.2. ['IV.5/4.4]

'IV.'2/,.I'.2. ['IV.5/4.4.]
IV.I.,.I'.'2. [IV.5.4.3'.]

New Caledonia (Iddings, p. 652)

Hornblende -anorthosite

Anorthosite

Hornblende-gabbro

Norite .

Ouenite

Hornblendite

Diallagite .

Bronzitite .

Phonolite .
Tinguaite .
Nepheline-syenite

I'.5-4.5-
I.5/5.5.
II.5.4/5.
III.4-4'5-

III.5/5.4'.
III.5.5.5.

'IV/2.,2.2. ['IV. 5 .4.(4)5-]
IV.1%2.2. [IV. 5 / 4 .(4)5.]
'V.i. , .1.1'. ['V.5.4'4.]

Ill
Tahiti (Iddings, p. 653)

. . I'.5-i'.4.
. r.6.1.4.
. 'II/6/2.3.

1 The use of round brackets in a symbol indicates that the magma is transi-
tional, and near the border line between two compartments. Thus 1(1 1.)
indicates a rock in Class I., but transitional to Class II. The use of dashes
before or after a figure indicates that the rock is intermediate between the
division in which it actually falls and the preceding or succeeding one. Thus
II.' indicates a rock in Class II., but intermediate towards III. II. (III.) would
indicate a rock in Class II. still closer to III. See CI. P. W.,Joum. Geo/, xx.
(1912), pp. 550-61.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 71

Hauynophyre

Camptonite

Nepheline-monzonite

Nepheline-gabbro

Microgabbro

Basalt

Felspar-basalt

Microlitic Picrite

Essexitic Gabbro

1 1.672.4.

II.6'.2.4.

11/6.(2)3.4.

IL'6.3.4.

Ill 5 3-4

III.5/4.4.

III.6.3.4.

IV.l'.„.l'.2.

'IV.2. 2 .2.2.

[IV.5.4.4.]

['IV.6.' 4 . 4 (5)-]

MONTEREGIAN HlLLS, QUEBEC (IddingS, p. 375)

Nordmarkose

Laurvikose

Laurdalose

Akerose

Essexose

Andose

Hessose

Palisadose

Yamaskose

Yamaskite

Hawaii

Trachytic Oosidian

Felspathic Lava

Andesitic Basalt

Andesite

Trachydolerite

Lava .

Hornblende-basalt

" Pelee's hair "

Lava .

Andesite

Kauaiite

Basalt

Basalt-pumice

Basalt-obsidian

Basalt

Scoria .

Olivine-basalt

Lapilli

Basalt .

Olivine-basalt

Nepheline-melilite-basalt

Gabbro

Nepheline-melilite-basalt

I'. 5 '.i'.'4.

r.5.2.4.

'II.6.1.4.
'II. 5.2/4.
II.S.2.4.
II.6.2.4

II. 5/3/4.

H.5/3-4'.

'II. 5.475.

IV.i. 2 .2.2. [IV.5(6). 4 .4.]

IV.2'.v'3.2'. [IV.574.4.]

IV.' 3 .,(2)3. 3 . [IV. 5 (6). 4 .4-]

V
(Iddings, pp. 654-5)

(I)II.5'.i-4.

(1)11.5-2.4.

H.5-3-4.

II.5(6).2. 4 .

II'.5-3.4.

H'.5-3.4(5).

II(II1).5.2.4.

II(III).5. 3-4(5)-

II(III). 5 .3'.4(5).

II(III).'6. 3 .(3)4-

III/5.2.4'.

IH.5-3-4.

111.5-3-4(5)-

IH.5-3'.4(5).

IH.5-4.4-5-

III'. 5.4.4-5.

III(IV).6(7).2(3)4(5).

(III)IV.i(2)..,u(2).2. [(III)IV.5. 4 .4(5)-]

(III)IV.2.,.2'.2'. [(IIOIV.9.I.4'.]

'IV.l(2).- 3 .2.2. ['IV. 5 (6). 4 .4'.]
'IV.l'/ a .i(2).2. ['IV.5.4.(4)5-
'IV.2 (sU .2(3).2(3). ['IV.9.1.4.]

IV.I(2).I'.2. [IV. 5/4.(4)5.]

IV.2/ 3 .2.2. [IV.7'.3-(4)5-l

SCIENCE PROGRESS

In each of these series a great contrast is observed between
the symbols of rocks in Classes IV. and V., and those in Classes
I., II., and III.; but when the salic ratios as used in Classes I.,
II., and III. are also used for the calculation of rocks in Classes
IV. and V., the symbols thus obtained show a great congruity
with those obtained for the more salic rocks (compare symbols
within square brackets with those of the rocks in Classes I.,
II., and III. preceding). For example, in the first eleven rocks of
Series I. it is clearly seen that, while the Classes range from
I. to III. (persalic to salfemic), the orders remain indicated by
5 (perfelic) with the exception of one which is 4' (intermediate
between 4 and 5); and eight of the rocks are dosodic (indicated
by 4 in the last figure of the symbol). The remaining two are
sodipotassic transitional to dosodic 3 (4), and persodic near
dosodic ('5). The third figure, however, varies with the Classes,
ranging from peralkalic (1) to docalcic (4), and illustrates ad-
mirably the usual increase in the anorthite molecule of the
felspars concomitantly with increase in the proportions of the
femic constituents. The last three rocks of the series fall into
Class IV. (dofemane), and their symbols, calculated by the
methods of the Quantitative Classification for rocks in Classes
IV. and V., are hopelessly incongruous with those of the other
ten. If, however, they are calculated by the methods used for
rocks in Classes I., II., and III.— that is, on the ratios obtaining
between the salic constituents— their relationships with the rest
of the series at once become evident. They are perfelic and
dosodic, and thus fall in with the magmatic character of the
salic portion of the series. The magmatic character of the
whole series is therefore well defined. With a variation from
persalic to dofemic there is a sympathetic variation from peral-
kalic to docalcic, whilst the rocks throughout the series remain
dominantly perfelic and dosodic.

Similar analysis of the Series II., III., and IV. affords similar
results. The magmatic character of Series II. (New Caledonia)
is exceptional in that the rocks remain docalcic to percalcic
throughout, although the classes range from persalane (I.) to
perfemane (V.). In Series V. (Hawaii) five of the rocks in
dofemane (IV) give results which prove them to be the con-
tinuation of that part of the series which falls in Classes I.,
II., and III. The remaining two, however, do not conform
to the series so far as is indicated by the magmatic symbol

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 73

obtained from the salic ratios. It is not clear whether this is
due to the rocks belonging to a different series, to a defect in
the method of obtaining the symbol, or to defects in the method
of calculating the norm.

It is thought that enough has been adduced to show that
the utilisation of the salic ratios throughout the classification,
instead of only in Classes I., II., and III., as at present, would
at least give better results than the present method, especially
in indicating serial relationships between rocks. Moreover it
would do away with an awkward asymmetry in the Quantitative
Classification as at present constituted.

It may be objected that as some rocks in perfemane are
totally devoid of salic constituents it would be impossible to
treat them as suggested in the foregoing discussion. This
is certainly true ; it is a defect inherent in a dichotomous
method. The difficulty also occurs in the Quantitative Classi-
fication in the pure quartz-rocks at the other end of the series.
Here it is impossible, or at least inexpedient, to carry the
symbol representing the magmatic position of the rock beyond
the Order. Thus a quartz-rock from Secucuniland, South
Africa, and a quartz-granite from Eskdale, Cumberland, are
represented by the symbol I. 1.-. -(see Iddings, Igneous Rocks,
vol. ii. p. 31). Similarly at the other end of the series, and
under the method of calculation adopted in the foregoing
discussion, rocks devoid of salic constituents would simply
have the symbol V.-.-.-., indicating the Class in which they
fall. The matter is of small practical importance. For example,
it would affect only five rocks out of 34 belonging to Class V.
(perfemane) in Iddings' tables of rock-analyses — that is, five out
of over 2,000, considering the whole series of analyses.

Suggestions towards a Quantitative Modal Classification

It will be evident from the foregoing that the writer con-
siders the only classification which will meet the immediate
needs of petrographers is one that is at once quantitative
and modal. A quantitative classification is admittedly purely
utilitarian. However constructed, it will probably "correspond
to nothing that has occurred in the evolution and differentiation
of igneous rocks," but it is none the less necessary for their
comparative study. Petrographers will always require a pigeon-
holing arrangement whereby they may accurately docket rocks

74 SCIENCE PROGRESS

of mineralogical or chemical similarity. Furthermore a modal
classification, whatever its difficulties, is the one based on the
characters most readily elicited from the rocks themselves. It
will, at any rate, be more convenient, save for special purposes,
than a normative classification which requires a tedious process
of chemical analysis before a rock can be placed in its proper
position.

Difficulties at once present themselves when a quantitative
classification on modal lines is considered. The texture of
many rocks is such that the mode cannot be elicited at all ;
and in the case of merocrystalline and porphyritic rocks,
Iddings has justly pointed out the anomalies that result from
a classification based simply on the identifiable crystalline
constituents regardless of the composition of the minutely
crystalline or non-crystalline remainder. 1 Furthermore a dif-
ficulty arises in the fact that the same mineral species may
vary considerably in chemical composition in different rocks.
The phenomenon of "occult" minerals is in this connection
to be considered as a special case of variable chemical
composition.

Before any system can be applied it is necessary, therefore, to
consider the methods by which the mode may be obtained from
various kinds of rocks. With the holocrystalline granular rocks
there is very little trouble. The graphic method of quantitative
mineral measurement invented by Rosiwal yields sufficiently
accurate results for classificatory purposes in the great majority
of types. It might here be said that the degree of accuracy
required in the estimation of the mode depends on the size of
the classificatory divisions it is proposed to erect. If the latter
are to be as comprehensive as, say, the subrangs of the American
Quantitative Classification, a great degree of accuracy is not
necessary. In many cases the experienced petrographer can
estimate the quantitative mineral composition of the rock from
a careful examination of the thin sections with sufficient accuracy
for this purpose.

The expression of the mode in aphanitic rocks is more
difficult, since they are frequently insusceptible to the Rosiwal
method. The approximate mode of a quite fine-grained rock,
however, may be obtained by this method provided that it is
holocrystalline. It must be admitted, however, that with the

1 Igneous Rocks, vol. ii. 1913, p. 72.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 75

material at present available to the petrographer it is inevitable
that chemical analysis will have to be resorted to in order to
determine the mode of an aphanitic rock. In any modal classifi-
cation on quantitative lines it seems necessary to assume that
the plutonic noncrystalline rocks are those affording the primary
units for classification, and to treat the aphanitic rocks as
textural modifications of these. In the case of porphyritic rocks
the proportions of different kinds of phenocrysts to one another
and to the groundmass could easily be estimated by the Rosiwal
method. There is need for the chemical investigation of a large
series of typical groundmasses with a view to the determination
of their average modes. These could be used in calculation in
much the same way as the analyses of pyroxenes, amphiboles,
and micas collected by the authors of the Quantitative Classifi-
cation are used for the purpose of modal calculation. 1

It is admitted that the treatment of the aphanitic rocks on
modal lines constitutes a serious difficulty in the way of modal
classification. It is a difficulty, however, which may be largely
removed by future work. Furthermore, it is believed that an
estimation of the mode of many aphanitic volcanic and hypabyssal
rocks can be made with sufficient accuracy for classificatory
purposes. For example, generally with the aid of a Rosiwal
measurement supplemented by calculation from the chemical
analysis, Washington has estimated the modes of many fine-
grained leucitic and other lavas from Italy. 2 In the description
of aphanitic rocks even an approximate estimation of the mode
by a careful examination of the thin section would be better
than no estimation at all, and would help to fit the rock
into one of the larger compartments of the quantitative modal
classification.

Notwithstanding the opinion of Williams, 3 the Rosiwal
method of estimation is capable of giving extremely accurate
results. 4 The writer has recently used it for the investigation
of teschenites and related rocks of Central Scotland, and has
found the chemical composition calculated from the results of
the Rosiwal measurement to be strikingly accordant with that
obtained by ordinary chemical analysis.

1 C.I.P.W., Quantitative Classification of Igneous Rocks. Tables XI I. -XIV.

2 The Roman Comagmatic Region, Publications Carnegie Inst., No. 57.

3 American Geologist, xxxv. 1905, pp. 34-46.

4 F. C. Lincoln and H. L.. Rietz, Economic Geology, viii. 191 3, pp. 120-39.

7 6 SCIENCE PROGRESS

The fact that certain mineral species may vary somewhat in
chemical composition ceases to be an objection to modal
classification when chemical composition is deposed from the
position of chief factor in quantitative classification. For a
purely utilitarian purpose of classification the petrographer
after all is not so much concerned with comparing the chemical
composition of rocks as in comparing their modes. If the rocks
be treated simply as classifiable objects, the differences in the
chemical composition of certain mineral species become as
immaterial as the individual differences between animals of the
same species ; or if a higher grade of importance be assigned to
these variations they may be compared to varietal differences in
the same species.

To take a classic example, the hornblende-rock of Gran
is as well, or perhaps better, classified with other hornblende-
rocks than with the camptonite associated with it in the field,
although it is nearly identical in chemical composition with the
latter rock. It is better to classify a rock consisting of horn-
blende with other hornblende-rocks, even though they differ
somewhat chemically, than to classify it with a rock consisting
essentially of plagioclase and hornblende.

That magmas of identical chemical character may and do
crystallise into two or more different mineral aggregates in
response to differing conditions is an argument rather for separat-
ing the various products in classification than for bringing them
together. A chemical classification only takes into consideration
the chemical composition of the magma from which the rocks
have been derived. A classification taking cognisance of the
modal habit of the rock also takes into consideration the con-
ditions under which solidification occurred, and therefore has a
more genetic character than the chemical classification. A
modal classification treats the rocks as mineral aggregates
with a history ; a chemical classification treats them merely
as magmas. 1

Having obtained the mode or actual mineral composition of

1 C. P. Berkey, speaking of the Quantitative Classification, says : " It is a
splendid magmatic classification scheme. But in real life we are dealing not
with magmas so much as the products of magmas which, because of differing
conditions, have given rocks that do not usually agree wholly with their
theoretical behaviour." — "Objects and Methods of Petrographic Description,"
Economic Geology^ viii. 1913, p. 701.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 77

our igneous rocks, the next step is to consider the best method
of subdivision and classification. It is argued in this paper that
as the felsic constituents form more than 79 per cent, of the
mass of igneous rocks, the dominant factors in classification
should be based on them, and that the subordinate mafic con-
stituents should have a correspondingly subordinate place.
Consequently the main classes must be based on felsic ratios-
Fortunately we have alread}' to hand the main lines of an
excellent classification devised by Iddings on this basis in his
new book. His principal divisions are as follows :

Division I. Rocks characterised by quartz.

,, II. „ „ quartz and felspars.

„ III. ,, „ felspars.

„ IV. „ „ felspars and felspathoids.

,, V. „ „ felspathoids.

„ VI. ,, „ mafic minerals.

These divisions have definite quantitative limitations. In
all save the last, the ratio of felsic to mafic constituents
must exceed three to five. Then in

Quartz v 5

Division I. ^— ; ■- > —

Felspars x 3

Quartz , 5 x j_

" ' Felspars ^ 3 ' 7

Quartz or Felspathoids , 1

" ' Felspars ^ 7

Felspathoids
Felspars

< JL > JL

x 3 X 7

Felspathoids v 5

" Felspars ' 3

Felsic minerals , 3

" ' Mafic minerals ^ 5

It is impossible in the limits of this paper to follow out
completely the further details of the classification. As a sample
the method of dealing with Division III. will be cited.
Further subdivision of III. is based on the kind of felspar
present. Alkali-felspars (orthoclase, microcline, anorthoclase,
albite) are contrasted with lime-soda felspars (oligoclase to
anorthite). On this basis the following divisions are made:

. _ . Alkali-felspars , 5
A. Syenites . . . 7-. 3 — ri < -r

Lime-soda felspars x 3

Alkali-felspars , 5

Lime-soda felspars ^ 3 5

Alkali-felspars ^ 3

Lime-soda felspars ' 5

Alkali-felspars , 5

B. Monzonites . . ,-■ ^— ^ < > ,

Lime-soda felspar

C. Diorites and Gabbros , Alkali-felspars y ±

SCIENCE PROGRESS

The diorites are characterised by oligoclase and andesine ;
the gabbros by labradorite, bytownite, and anorthite.
The syenites are subdivided as follows:

Felsic minerals
Group Ai. [Prefelsic syenites] .

i. Alkali-syenites

> 1
Mafic minerals x 3

Alkali-felspars

Lime-soda felspars

>-?

Alkali-felspars

2. Calcialkalic-syenites

Group A2. [Mafelsic syenites] .

Mafic minerals

Lime-soda felspar

5 < f >

Felsic minerals / 5

Monzonites have only been divided into

Felsic minerals

Group Bi. [Prefelsic monzonites]
Group B2. [Mafelsic monzonites]

3 X 5

Mafic minerals
Felsic minerals
Mafic minerals

Group C. — Diorites and Gabbros — is divided similarly.

Methods of subdivision similar to the above are adopted
in all the main Divisions.

It is obvious that this method of classification fulfils the
conditions laid down in this paper. It is modal and it is
quantitative. The scheme forms an excellent ground-work
on which to build up a stable quantitative system of classifica-
tion based on the mode. Several criticisms of Iddings' arrange-
ment can be made. The first is that his sixth division, that
characterised by mafic minerals, is really unnecessary. The
rocks included in this division are collected from most of
the other divisions, in increasing quantity from the first or
second onward, and form merely the domafic and permafic
members of these divisions. Division VI. is not co-ordinate
with the other divisions, but traverses them, as can be seen
from the diagram.

Rocks charac-
terised by
quartz.

Rocks charac-
terised by quartz
and felspars.

Rocks charac-
terised by
felspars.

Rocks charac-
terised by felspars
and felspathoids.

Rocks charac-
terised by
felspathoids.

Perfelsicj
Dofelsic I
Mafelsic J

Division I.

Division II.

Division III.

Division IV.

Division V.

Domafic "i
Permafic J

Division VI.

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 79

Division VI., consisting of rocks with dominant mafic con-
stituents, is really a survival of the ultrabasic class of the
qualitative classifications. The ultrabasic rocks, however, occur
in very small quantity as compared with those of most of the
other divisions. They rarely form independent masses, large
or small, and are usually encountered as differentiation-facies
of rocks belonging to the other divisions, especially III., IV.,
and V. Moreover, the erection of a division based on mafic
minerals contravenes the principle that the main factor in
igneous rock classification should be based on the predominant
felsic minerals. The proportions of the mafic constituents
are sufficiently recognised by the erection of groups based
on the felsic mafic ratio (see subdivision of the syenites,
ante p. 78). It is in accordance with the results obtained
in the foregoing discussion that the rocks of Iddings' Division
VI. should be distributed amongst the other five divisions,
where they would at once find their place as the domafic
and permafic members of these divisions. 1

A second criticism is that the second factor in the majorit}^
of the classes is the ratio of alkalic to lime-soda felspars.
The latter may range from oligoclase to anorthite. Albite,
which from a mineralogical point of view, forms part of the
plagioclase series, is, however, and rightly, treated as an
alkali felspar. But as the lime-soda felspars contain the albite
molecule in varying proportions, the latter appears in both
the quantities that form the ratio. This is neither necessary
nor desirable. What is required is to contrast all the alkali-
felspar with all the lime-felspar ; and to that end the albite
molecule included within the lime-soda felspar should be
counted with orthoclase and pure albite in the numerator of
the fraction. As pure albite rarely occurs independently in
igneous rocks, and only to a small extent in solid solution
or isomorphously mixed with orthoclase (as soda-orthoclase,
anorthoclase, etc.), the ratio used by Iddings essentially con-
trasts the orthoclase molecule on the one hand with the
albite plus the anorthite molecules on the other. This,
however, is a meaningless ratio as compared with that of
orthoclase plus albite to anorthite. The latter expresses

1 Holomafic rocks could be treated as suggested for the holofemic rocks ;
from their affinities and paragenesis it should be possible in the great
majority of cases to determine in which Divisions they should be placed.

8o SCIENCE PROGRESS

the common and significant variation in igneous rocks which
has given rise to the conception of alkalic and calcic
" branches."

It is considered therefore that this ratio should replace
that used by Iddings, especially as it is quite as easily obtained.
From the optical examination it is now possible to determine
the composition of the lime-soda felspars quite accurately ;
and it is then only necessary to add the amount of the albite
molecule to the alkali-felspar already quantitatively determined,
and to use the remaining amount of anorthite as the denomi-
nator of the fraction, in order to obtain the required ratio
between the alkalic and calcic felspars. Complications are
introduced by the frequent zonal structure of the plagioclase
felspars, making it difficult to estimate the proportions of
the albite and anorthite molecules ; and by possible perthitic
intergrowths of lime-soda felspars with orthoclase. But the
errors introduced by these difficulties in the estimation of
the felspar ratio will not commonly be so large as to shift
the rock from its rightful place in the classification. The
grade of accuracy required in the quantitative estimation is
governed by the size of the classificatory compartment into
which it is desired to introduce the rock ; as and it is probable
that the compartments of the modal classification would not
be smaller than the subrang of the American Quantitative
Classification, a high grade of accuracy would not be re-
quired.

A third criticism of Iddings' classification is that while it is
ostensibly based on the mode it is the norm that is most fre-
quently used to determine the place of any particular rock. It
must be admitted that this is largely due to the paucity of data
at his disposal as to the modes of igneous rocks. It is a diffi-
culty that only future work will remove ; and its discussion
here may serve to remind descriptive petrographers how vital it
is to systematic work to give as many and as accurate estima-
tions as possible of the modes of the rocks they describe. In
the persalic and dosalic classes of the American Quantitative
Classification the ratio of salic to femic constituents is, however,
nearly the same as that of felsic to mafic. Similarly the dif-
ferences between the ratios of quartz or lenads to felspars, and
between the felspars themselves, are negligible from the point of
view of classification. This has been ascertained from the

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 81

consideration of a number of rocks in which both norm and
mode are available. Hence, in the absence of the mode, the
norm may be used for modal classification with little possibility
of error in rocks belonging to persalane and dosalane.

Whilst the modes of many rocks are normative, they are pro-
bably more frequently somewhat abnormative ; and this has given
rise to some curious anomalies in Iddings* classification. For
instance, the anorthite appearing in the norm of a " monzonite "
may in part be taken up in the mafic minerals, and there-
fore fail to appear in the form of lime-soda felspar in the mode.
Rocks of this type, therefore, called monzonites in Iddings'
classification on the strength of the ratios of alkalic to lime-soda
felspars calculated from the norm, may actually be devoid of
modal lime-soda felspar. But the presence of the latter in
amount roughly equal to the orthoclase, is the essential part of
the original definition of monzonite. Many similar anomalies,
caused in the same way, could be cited ; but until as many
modes have been accumulated as there are norms, it is probable
that this difficulty will not be completely obviated.

It may be remarked that the range of rocks covered by
Iddings' divisions, excluding that based on the mafic minerals,
might equally well be treated as divisible into nine equal
compartments, based on ratios between quartz or lenads to
felspars analogous to those that form the nine orders in
Classes I., II., and III. of the American Quantitative Classification.
The diagram makes this clear.

Division I.
Rocks charac-
terised by quartz.

Division II.

Rocks characterised

by quartz and felspars.

Division III.

Rocks charac-
terised by
felspars.

Division IV.

Rocks characterised

by felspars and fels-

pathoids.

Division V.
Rocks charac-
terised by

felspathoids.

Order
1.

Order
o

Order
3.

Order

Order
9.

Q>2

F'l

Q/K3
FYS

Q/KI

F K S / 7

Qor L ,i
~F"^7

Kl/3
F/ 7 S

t\3/i
F 7 5S

L>I/7

K7
F' 1

A quantitative mineralogical classification of igneous rocks,
based on essentially the same principles as that of Iddings,
has recently been devised by F. C. Lincoln. 1 The chief difference

1 F. C. Lincoln, " The Quantitative Mineralogical Classification of Gradational
Rocks," Economic Geology \ viii. 191 3, pp. 551-64.
6

82 SCIENCE PROGRESS

is that Lincoln prefers a three-fold to a five-fold subdivision.

1 1 is main divisions are as follows :

Felsic v 2
Division A. Leucocratic . . jyf~ fic / y

Felsic / 2 v i
„ B. Mesocratic . . ^^ < y > y

Felsic / i
„ C. Melanocratic . ^^ <^ y

Divisions A and B are further subdivided on the basis of
the ratio of quartz or felspathoid to felspar, and Division C on
ratios subsisting between ferromagnesian silicates and ores. It
is only possible here to cite the treatment of Division A as a
sample of the method. Division A is subdivided as follows :

Q V 2

(a) Quartz group . . . -pr / y

Q / 2 x I

{b) Quartz-felspar group . . -pr \ — / y

Q or L / i
(V) Felspar group . . . — p — \ y

L \ I / 2

id) Felspar-felspathoid group . v / y \ y

L v 2

(i?) Felspathoid group . . p / —

Further subdivision is made in groups (b) and (c) on the
basis of the percentage of orthoclase to total felspars present,
and in groups (d) and (e) on the percentage of leucite to total
felspathoids, giving rise to thirteen series.

This mode of arrangement may be subjected to precisely the
same criticisms as have been applied to that of Iddings. A
further criticism is that the ultimate compartments are far too
comprehensive. Take, for example, group (c), in which the
ratio Q or L to F is less than one to two. This is subdivided
into three series on the basis of the percentage of orthoclase in
total felspar present as follows :

Series V. Syenite-Trachyte . Percentage of orthoclase 100-67
„ VI. Monzonite-Vulsinite . ,, „ „ 67-33

„ VII. Diorite-Andesite . „ „ „ 33-0

Taking the extreme variations, the syenite-trachyte series

may contain rocks of the following composition :

1. n.

Quartz 33 o

Orthoclase 67 30

Lime-soda felspars . . . . .0 15

Felspathoids o 22

Mafic minerals ...... o 33

A REVIEW OF IGNEOUS ROCK CLASSIFICATION 83

Both these rocks are leucocratic. In I. quartz forms 33 per
cent, of the whole, and in II. felspars make up 67. per cent, of
the leucocratic minerals. Hence both rocks fall into group (c).
In I., moreover, orthoclase forms 100 per cent., and in II.
67 per cent., of the felspar present. Hence they both fall into
Series V. On comparison of the mineral composition, however,
these rocks are seen to be widely different. One is a holo-
leucocratic granite ; the other is a nearly mesocratic felspathoidal
monzonite. Hence it must be agreed that the three-fold method
of partition results in far too comprehensive compartments.

A. N. Winchell has recently devised a useful modification of
Rosenbusch's classification. 1 His main classes are peralkalic,
alkalic, and alkalcic (= alkali-calcic). Symmetry would seem
here to demand a percalcic class also. The next co-ordinate
used is that of occurrence and incidentally texture. The rocks
are divided into plutonic, hypabyssal, and volcanic groups.
The hypabyssal is further subdivided into the aschistic and
diaschistic types (the latter with both felsic and mafic varieties) ;
and the volcanic into felsitic and glassy types. The third factor
in the classification is mineralogical, and subdivides the rocks
according]to whether they have alkali-felspars, soda-lime felspars,
or are devoid of felspars. A further mineralogical division is
employed which, however, differs in detail in each of the three
main classes.

No quantitative relations whatever are formulated to regulate
the application of the various factors employed ; but tables
showing the average chemical composition of the principal
rock-types are appended to the paper. This is an admirable
rearrangement of Rosenbusch's plastic qualitative classification.
With one or two further modifications (as, for example, the
institution of a percalcic class, and the recognition of the felsic-
mafic ratio throughout), and with a certain amount of quantita-
tive stiffening, it would form an excellent classification to
present to students in geology classes, from which, in a more
advanced stage, they could pass to the more elaborate quantita-
tive classification based on the mode.

1 Rock Classification on Three Co-ordinates, Journ. Geol. xxi. 1913, pp. 208-
23-

8 4 SCIENCE PROGRESS

Conclusions

The present trend of penological thought is toward an
increasing recognition of the quantitative element in the science.
A quantitative classification is demanded merely on the grounds
of utility, especially for the purpose of comparing and correlating
igneous rocks, for which qualitative descriptions afford only a
very vague and inconclusive basis. With the exception of
chemical and mineralogical composition, all the bases of classifi-
cation hitherto proposed are insusceptible to the quantitative
method. A quantitative classification based on chemical com-
position is a desideratum for various purposes, but is unsuitable
for the everyday working needs of petrographers, because the
chemical analysis of a rock usually takes at least a week of the
petrographers time, and it is therefore impossible for him to
obtain data for all the rocks he wishes to classify. The mode
of a rock is much more easily obtained, and is quite as sus-
ceptible to the quantitative method as the chemical composition.
The main lines of a suitable modal classification are already
formulated in the second volume of Iddings' great work on
Igneous Rocks. With a little modification in detail, and
elaboration on the scale and with the method of the American
Quantitative Classification, it is believed that it will satisfy the
immediate needs of petrographers. If and when they are
elucidated, the natural or genetic relations of igneous rocks
will be as easily expressed in terms of the quantitative modal
classification, as various physical relations are expressed in
terms of the artificial and arithmetically bounded units of the
scale of temperature and other physical properties.

THE CAUSE OF VARIATION

BY ARCHER D. WILDE

It is a trite observation, said Darwin, that no two creatures
in nature are alike, and fifty years of Darwinism have not made
it less so. I will not therefore trouble my readers with any
considerable expansion of the theme, but rather adopt it as a
postulate, not only that there are no two creatures alike, but
also that if two of the likest possible, for example two animals
of the same litter, or two cells derived by fission from one,
are compared, they differ in every particular. And not only so,
but no two parts of the same creature are alike. Like as they
seem to the eye, two hairs of the same animal, placed under
a microscope, are at once seen to differ ; and drawings of
cellular structures seen under high microscopic powers show
that no two contiguous cells resemble each other exactly.
Throughout organic nature general similarity is accompanied
by unlikeness in detail. As between parents and their offspring,
as between the several offspring of the same parents, and more
widely as between the members of any generation of any kind
of plant or animal, these differences are called variations, and
much labour has been expended in attempts to account for their
origin. These I pass over at present, but one hypothetical
question regarding such individual differences I wish to ask, in
order to answer it in my own way. If by microscopes of con-
tinually increasing power we could examine the structure not
only of the cells, but also of their component plasms or
materials, and again the structure of the units of which these
materials might be found to consist, where ultimately should we
find these differences end ? Not long ago the answer would,
I suppose, have been, " In the chemical molecules at all events,
if not before reaching them, will be found units absolutely alike
in all respects." Recent discoveries in physics have however
now given grounds for the belief that not even the atoms of
the same element are exactly alike, for even apart from internal
motion they may be in different stages of a slow disintegration.

86 SCIENCE PROGRESS

But it is evident that this is going further than there is any
need or right to go in biology, and I mention it only to
show to what a depth this law of unlikeness goes in natural
phenomena. Assuming such differences to exist, then however
they may possibly affect life, it is surely not in them that we
are to seek even the ultimate factors of the far greater differences
between one living being and another. P^or biological purposes
we must assume what is probably not true, that all atoms of
the same element are exactly alike. More, that each of the
highly complex chemical compounds, in which atoms are united
to form the bases of living matter, also consists of molecules,
of which every one is exactly like every other in weight, size,
shape and the arrangement of its component atoms. When
however we consider the manner in which the materials of
which a cell is built, or the units, be they what they may,
which compose those materials, are constructed out of these
theoretically uniform bricks, the chemical molecules, we must
suppose that at some stage or other structure comes into
play, and that the generally similar homologous parts of
two like individuals must differ ultimately in the number and
arrangement of the bricks of which they are composed. They
may no doubt differ in some degree in the kind of bricks, for
while all life is largely composed of the same chemical com-
pounds, and the homologous parts of like animals must be
almost entirely so composed, yet it is certain that some forms
of life contain chemical compounds absent from others, and it
seems not doubtful that two closely allied individuals, even
two animals of the same litter, apart from morbid changes, may
congenitally contain different chemical compounds resulting
in differences in pigmentation and other characters. But as
between animals of a kind this difference may be neglected ;
it is in the others that variations appear in the last analysis
to consist. Two like animals differ because their parts differ,
these because their constituent tissues differ, these again
because their component cells are unlike, and finally these
differ because either they, or the ultimate units of which they
are composed, are built of unlike numbers of like molecules
dissimilarly arranged.

All this is of course far from being new, and it is mainly
speculative, having little inductive support derived from observa-
tion. What validity it may have is derived rather from necessi-

THE CAUSE OF VARIATION 87

ties of thought. As long ago as 1689 Locke referred our ideas
of the primary qualities of bodies to the " bulk, figure, number,
situation, and motion of their parts." Since his day we have
learnt much about these " parts," and in the light of modern
knowledge we may paraphrase his words by the expression
" kind, number, and arrangement of the component molecules,"
because the "bulk and figure" of these depend on their kind,
which also determines their motion and the manner of their
response to the motions reaching them from the environment.
And as the primary qualities of a body are referable to these
factors, so also must the differences between any two be referred
to differences between these factors. It would appear moreover
that the analysis may be carried one step further, resolving the
factor of arrangement into the two others. For in the growth
of organic matter the positions taken up by the molecules must
depend upon their natures and numbers. The differences
between any two like individuals are therefore results of the
differences in the numbers of the chemical molecules in the
cells they grew from — a proposition which, I may perhaps
be told, might have been assumed at the outset. An important
consequence should however be noted. As the differences
between any two such cells consist only in differences in the
numbers of the molecules composing them, it follows that
all variations must be in one or other of two directions— plus
or minus, greater or less — and it is inaccurate and misleading,
though very common, to write of them as occurring " all round
a centre," " in every possible direction." They must in every
particular be above or below a mean, and there is no third
alternative.

When the matter is thus considered in a general way, it
becomes evident that all that has been said applies not merely
to living bodies, but to all bodies, organic and inorganic alike.
Locke's words are of course perfectly general. Mountains,
rivers and clouds, as well as animals and plants, show striking
general resemblances accompanied by endless differences in
detail. Not only are no two leaves alike on a tree, but the same
may be said of the pebbles on the beach, and with the aid of
a microscope the truth is found to hold even of the grains
of sand on which they lie. Many rocks look homogeneous
enough, but on being examined in thin plates under high
powers they reveal a complicated intimate structure. Organic

88 SCIENCE PROGRESS

variation being then only the expression in plants and animals
of an infinite differentiation common to organic and inorganic
nature, it is idle to search for its ultimate causes in phenomena
which are subsequent to life. Sex has been suggested as a
cause, but is itself a variation of life, as life itself is but a
variation of inorganic nature, and therefore it cannot be the
cause. The effects of the environment upon a parent, supposed
on very inadequate evidence to be transmitted to their off-
spring, have been pressed into service as causing or contributing
to cause variation. But there is no need to spread the net so
wide, and it is unreasonable in accounting for a phenomenon
everywhere manifested throughout the universe to bring in
causes peculiar to life. Variation, differentiation, the produc-
tion of the unlike out of the like, is a part of the universal
scheme of things. The power to vary is a gift passed on to
the organic world by the inorganic from which it sprang. The
word differentiation was at first part of the formula in which
Spencer summed up the course of evolution, and though it
was afterwards discarded, its essence remains, and it seems
questionable whether the formula gained by the change. If one
word could sum up the process of the suns from a homogeneous
nebula to the complexity of mundane affairs, that word would
be differentiation.

The ultimate cause therefore of organic variation is the
same as that of differentiation in general. Variation is a phase
of the phenomenon called by Spencer the instability of the
homogeneous — the tendency of like things to become unlike,
and of unlike things to become more unlike. It may accord-
ingly well be questioned whether the object of our search ought
not, instead of the cause of variation, to be the cause of
similarity. How is that wonderful constancy to type in all
that is essential to life preserved in the immensely complicated
organisms of the higher animals ? It is a question that is to
some extent being answered by the researches of cytologists
on the growth and division of cells.

All this however is naturally unsatisfying to the biologist,
who wishes to trace not merely the ultimate, but also the
proximate cause of variation in the organic world. How is this
universal tendency to change and divergence manifested in the
world of life, and especially in the higher animals ? I believe
it is possible by consideration of the mechanics of reproduction

THE CAUSE OF VARIATION 89

in cells in some degree to supply the answer. The proximate
cause of variation lies in the differential division of the un-
fertilised germ-cell. Those who have traced the process of
fission under the microscope, describe it as an elaborate
arrangement for securing an equal division of every part of the
mother-cell between the two daughter-cells. Their descriptions
naturally relate only to what they see, but it is difficult to doubt
that that process is carried out through every minute part of the
cell far beyond the range of vision. It is reasonable to assume
that the seen process extends to the unseen, and in no other
way can we imagine the powers of the mother-cell to be
transferred to both the daughters. The immense complexity
of the germ-cell of one of the higher animals is, I suppose,
generally assumed. At all events it seems to me a necessary
assumption. The brain of an ant has been called the most
wonderful piece of matter in existence, but it is nothing in
comparison with this speck of comparable size, of which a part
only, if the whole be fertilised and provided with proper food
and environment, develops into the brain of a man. When the
unfertilised cell divides into two daughter-cells, it is as if every
part of something far more complicated than a watch were
divided each into two equal and similarly shaped parts, and
the whole were put together again to make two watches of
smaller size. There must be many thousands of factors, each
with its special function to perform after fertilisation, should
this occur, in the growth of the animal or plant, and every one
must be equally divided between the two daughter-cells.
Being so numerous, these factors must be almost inconceivably
small, yet so much smaller are chemical atoms and molecules
that immense numbers may enter into the composition of each,
whether they are grouped, as is probable, into intermediate
units or not. I have said that on a fission each factor must be
equally divided, but here is the point, the division of the mole-
cules of each factor between the two daughter-cells can never
be more than approximately equal, or at least the chances are
immensely against such an event, and the division is therefore
differential. Let us assume what is extremely improbable, but
will equally well serve the purpose of argument, that a certain
very small factor of a cell about to divide consists not of millions,
but of so few as a hundred molecules of one very complex
chemical compound, and of nothing else. On a division the

go SCIENCE PROGRESS

chances are much against absolute equality. In the result let
us say that 52 molecules pass into one daughter-cell and
48 into the other. Before the next fission these two cells
have to grow to normal size — that is, they must be provided
with foods from which each factor can draw its appropriate
nourishment. All parts of the cell grow at approximately equal
rates, and the whole having to be doubled, each factor increases
in that proportion. Like the halving process, this process of
doubling will of course be inexact, but as there is no reason
for assuming a tendency either to excess or defect, an exact
doubling must be postulated on an average. The selected
factor therefore on the attainment of maturity consists of
104 molecules in the one cell and 96 in the other. On a second
division of the two cells into four there can again be no equality.
The selected factor in one of the four cells now produced must
consist of more than 52 molecules, let us say 53, and in one
other of less than 48, it may be 46, the other two being inter-
mediate. On maturity these numbers become 106 and 92, and
so on for subsequent divisions. We see then a constant, natural,
and inevitable tendency to divergence in respect of this par-
ticular factor. And what is true of this imaginary factor is
also true of all the many real factors that constitute a real
cell. In proportion as the number of molecules in each factor
is larger, the argument is the stronger, and although more
difficult to follow, it is not really altered if the molecules
composing each factor be of many different kinds. These cells
are produced in immense numbers, and there must contem-
poraneously exist among those of a single generation a great
variety of combinations of all the factors, each of which has an
equal chance of being called on by fertilisation to take part in
the continuance of the race.

Briefly the argument is that germ-cells are individuals, and
like all individuals they differ, even the twin cells, which result
from the fission of a single cell, not being exactly similar, for
we know that " no two creatures in nature are alike " ; and
owing to the method of reproduction by fission, there is a
continuous tendency towards a differentiation which accumulates
from generation to generation. This tendency appears to me
to be not so much a fortuitous as a necessary and universal
cause of variation in the animals which at intervals arise from
the germs. The hypothesis seems to accord well with the

THE CAUSE OF VARIATION 91

facts of heredity in general. In particular may be cited the
congruous fact that twins are often much more alike than
brothers or sisters born at long intervals of time. It also
affords a simple explanation of the evil effects of close in-
breeding, since closely related cells would be apt to resemble
each other in the excess or defect of particular factors. It is
applicable not only to the higher animals and plants, but to
all forms of life which are reproduced by cell-division, including
the monads, those lowest forms in which the history of the
cell is the whole life-history of the race.

If there is any force in these considerations, it would not
be surprising if some check were needed to counteract the
strong tendency that we here find towards variation. The
germ that nature has elaborated by slow additions through
millions of years of unbroken descent in a continuous line from
simple beginnings, if any form of matter can be called simple,
to its immense present complexity, has to be guarded against
a too rapid change in an environment that changes slowly,
rather than to be stimulated into variation. To cope with
our environment we must come extremely true to a type which
is proved by ages of survival to be the fittest. That sex is
a device by which such stability is increased is a thesis which
I have previously argued elsewhere, and need not here repeat.
It is one that appears to me to be supported not only by reason,
but by abundant inductive evidence. Briefly the means by
which sex effects a reduction of variations is the halving of
those differences which we have seen to be established by
repeated fission. Except where the two conjugating germ-
cells are closely related owing to in-breeding, it is unlikely
that the same factors will be much in excess or defect in both ;
and a factor that is much in excess in one must therefore
be assumed to be at about mean size in the other, so that that
excess will be halved in the fertilised cell. This halving appears
to be ensured by the " reducing division " of the cells which
precedes their conjugation.

In this differential division of the cell, if it be an agent in
producing somatic variation at all, we have a cause which is
certainly constant, and so far as concerns creatures which
are reproduced by the fission of cells, one which is also
universal. It will be worth while to notice into what troubles
and fallacies we are led by the refusal to recognise some such

9 2 SCIENCE PROGRESS

agent. They are well illustrated by Darwin's discussion of
the causes of variability in Chapter XXII. of his Animals and
Plants under Domestication, perhaps the least satisfactory that
ever came from his pen. In it he finally decides that the
variability of organic beings under domestication, "although
so general, is not an inevitable contingent on growth and
reproduction, but results from the conditions to which the
parents have been exposed. Changes of any kind in the con-
ditions of life, even extremely slight changes, suffice to cause
variability." On the other hand, as to two of the most important
changes that can be thought of, " a change of climate is not
one of the most potent causes," and " it is doubtful whether
a change in the nature of food is a potent cause." On the one
hand, " of all the causes which induce variability, excess of food
... is probably the most powerful." On the other hand, " the
goose and the turkey have been well fed for many generations,
yet have varied very little," while the thorn, hardly cultivated
at all, has varied much, and " seeds taken from common English
forest trees, grown under their native climate, not highly
manured or otherwise artificially treated, yield seedlings which
vary much, as may be seen in every extensive seed-bed."
Although " we may conclude with certainty that crossing is
not necessary for variability," yet " the crossing of distinct
species, besides commingling their characters, adds greatly to
their variability"; but as against this, "close inter-breeding
induces lessened fertility and a weakened constitution ; hence
it may lead to variability." If on the one hand a plant varies
on being cultivated, the change of conditions is supposed to
be the cause, but if, as in the case of the Swan River daisy,
no conspicuous change occurs until after seven or eight years
of high cultivation, this is taken for "good evidence that the
power of changed conditions accumulates." Surely all this is
very indifferent logic. It almost amounts to this, that the
presence of any one of the suggested causes and its absence
are equally effective in inducing variability, if and when it
occurs. Moreover, in a creature so shielded from the environ-
ment as is the germ-cell of the higher animals, all these influences
seem too remote. Even in monads, far more exposed to them,
changes of food and environment, except perhaps those occurring
at the moment of fission, would presumably rather affect the
rate of growth and reproduction of the cell than the manner

THE CAUSE OF VARIATION 93

of its division. There seems to be no escape from the con-
clusion from which Darwin unaccountably shrank, that there
exists in all living things an innate tendency to vary independent
of external conditions, and in his own language "inevitably
contingent on reproduction." " Nevertheless," he says, " when
we reflect on the individual differences between organic beings
in a state of nature, as shown by every wild animal knowing
its mate, and when we reflect on the infinite diversity of the
many varieties of our domesticated productions, we may well
be inclined to exclaim, though falsely as I believe, that variability
must be looked at as an ultimate fact necessarily contingent
on reproduction." But while he produces abundant justification
for such an exclamation, I can find no grounds for the reserva-
tion, " falsely as I believe." The whole argument sadly lacks
the beautiful obviousness and simplicity which so distinguish
the theory of natural selection. It has a strong flavour of post
hoc propter hoc. In wild creatures we do not usually know what
variations may occur. When they are domesticated, any
variation, or at all events any marked variation, is apt to be
noticed, and perhaps seized as a peg on which to hang a
new variety. When it occurs, anything convenient is set
down as the cause ; in imported productions change of climate,
in home-grown creatures change of soil, change or excess of
food, breeding out or breeding in, anything in fact but an
innate power to vary. Such vague and contradictory sug-
gestions give no rest or satisfaction to the mind, and incline
the student to resort to a cause which, if true, is necessary,
general, and in accordance with forces which are manifested,
not only in the variations of organisms, but throughout nature,
in a process of universal and unceasing differentiation. Such
a cause appears to me to exist in the differential division of
the cell.

In this passage Darwin finds the cause of variation in
change of the environment, nutrition being included in that
term. Weismann, who formerly held variation in the metazoa
to be effects of sex, and in monads to be due to the action
of the environment, afterwards admitted the force of the argu-
ments by which sex is shown to act in the opposite direction,
as a cause not of unlikeness but of likeness among the indi-
viduals of a species, and ceased to regard it as " the real root
of variation itself." This phrase and the following passages,

94 SCIENCE PROGRESS

extracted from his Evolution Theory, English Translation 1904,
show his opinions at that date, and I believe up to the present
time :

" Haycraft also finds the significance of amphigony simply
in the equalising or neutralising of individual differences which
it effects. Quetelet and Galton have attempted to show that
intercrossing leads to a mean which then remains constant.
Haycraft supposes that a species can only remain constant if
its individuals are being continually intercrossed, and that
otherwise they would diverge and take different forms, because
the ' protoplasm ' has within itself the tendency to continual
variation " . . . " the fundamental idea, that amphigony is an
essential factor in the maintenance ... of species, is un-
doubtedly sound . . . but we cannot simply suppose that
amphigony and variation are, so to speak, antipodal forces,
the former of which secures the constancy of species, the latter
its transformation. In my opinion, at all events, there is no
such thing as a ' tendency ' of protoplasm to vary, although
there is a constant fluctuation of the characters — dependent
on the imperfect equality of the external influences, especially
of nutrition." Thus the " real root of variation " is the same
as that alleged by Darwin. Nevertheless the stone here
rejected by the builder may yet become the head-stone of the
corner. It may be that sex and variation are " antipodal
forces," in that sex, by ensuring the communication of varia-
tions among large numbers of individuals, may check the
unlimited divergence that would otherwise ensue. Without
sex every individual line of living creatures tends to diverge,
like a tree growing into divergent branches; by sex individual
lines are bound together like intercrossing threads of a net-
work, and divergence occurs in the large communities called
species only in proportion as intercrossing is prevented or is
rare. Haycraft's " supposition " is really nothing but a fact. If
a species of animal, spreading over two areas, is kept from
free intercrossing by an intervening sea, or a beetle by a
mountain range, it invariably diverges into varieties, and
ultimately into species and genera. But as to the "tendency
of protoplasm to vary," this would be better expressed as the
impossibility of securing an exactly equal division of the matter
of a mother-cell, or of any part of a mother-cell, between the
two daughter-cells whenever fission occurs. In a subsequent

THE CAUSE OF VARIATION 95

passage Weismann says that the "ids" (hypothetical con-
stituents of the germ-cell, each of which is supposed to be
a "biological unit" virtually containing all the parts of an
individual) "differ very little within the same germ-plasm . . .
but are only absolutely alike in the case of two ids which have
been formed by the division of a mother-cell." To suppose that
any two such bodies can be absolutely alike is to run counter
to all we know of nature. If not even two atoms of an element
are exactly alike, such likeness cannot be postulated between
two relatively enormous bodies, each virtually, or let us rather
say potentially, containing all the parts of one of the higher
animals.

A PROBABLE CAUSATIVE FACTOR IN
THE AWAKENING OF POND LIFE

IN THE SPRING

By AUBREY II. DREW

The discovery of Auxetics by H. C. Ross has raised some
important points in biology, but perhaps one of the most im-
portant is that all living matter does not possess any inherent
capacity to reproduce itself until it has absorbed an auxetic.
Auxetics are substances which cause the multiplication of cells.
Some time ago I was able to show that the full development
of the spores of Polytoma granulosa (i) could be induced by
solutions containing auxetics, and I suggested the probability
that these organisms, as well as others existing in water,
required the presence of auxetics in order to develop. Pond
water always contains decomposing organic matter, and from
this fact one would suspect that auxetics must be present in
solution. Alkaloids have been shown by H. C. Ross to augment
the power of auxetics as much as five-fold, and to cause amoeboid
or kinetic action in leucocytes, and as pond water contains
organic matter in course of decomposition the presence of
kinetics might reasonably be expected. There is a further
question also raised, and that is that it is well known that the
organisms present in any given pond vary from time to time.
Thus one may find comparatively few organisms in a sample
collected from a pond, say, in January or February. A sample
collected, say, in March may show Vorticella as the chief yield,
while at another time perhaps Coleps or Paramcecia may be the
most plentiful. The same thing is seen still better in an
artificially prepared infusion, say, of grass. If such an infusion
be examined from day to day, it will be found that the first
organisms to appear are bacteria, then, somewhat later,
flagellates ; these are succeeded by ciliates, and it will be
noticed that at any given time one particular species of flagellate
or ciliate is usually more pronounced than others, and that these
often die out, to be replaced by different forms. Finally a
period is reached when all life tends to die out in the infusion,

9 6

AWAKENING OF POND LIFE 97

but bacteria may persist for a considerable time. No very
satisfactory explanation of this phenomenon has been forth-
coming as yet, but I think that, considered in the light of recent
researches, the point becomes intelligible. H. C. Ross dis-
covered the fact that cells possess what is termed a Coefficient
of Diffusion (2). This is measured by estimating the number of
units of stain alkali, etc., contained in the jelly film on which
the cells are placed, after subtraction of the units of salts
present, and by adding the units of heat and time requisite to
cause staining of the nucleus. The fact that all cells possess
this coefficient of diffusion shows that the medium on which
they are living must have the necessary index of diffusion before
absorption takes place. It is therefore obvious that supposing
an organism to possess a coefficient of diffusion of, say, 20, it
would not tend to multiply in an infusion till the fluid possessed
the necessary index, time and temperature, of course, being taken
into account. The coefficient of diffusion varies greatly in
different organisms, and, therefore, supposing two organisms
find their way into an infusion, the one possessing the lower
coefficient will multiply sooner than the one having the higher.
Finally a time might arrive when all the auxetic in the infusion
would be used up and development would then cease.

A further important point arises — viz. the great awakening
of life in springtime. Several theories have from time to time
been put forward such as increase in temperature, or an extra
amount of actinic rays from the sun, but none of these ex-
planations really meet the case. Now supposing it to be
demonstrated that an increase in either the auxetics or kinetics
or both took place towards spring in, let us say, pond water, we
should at once have an explanation of that awakening of life in
ponds which occurs in spring ; and, as it would be unlikely that
such an important phenomenon would have more than one
cause, we might reasonably conclude that the general develop-
ment of life in spring was also occasioned by an increase in the
auxetics and kinetics in the soil. I therefore determined to con-
duct a prolonged research to settle the following points. Firstly,
whether auxetics and kinetics do occur in pond water.
Secondly, whether there is any variation in the amount of these
bodies, supposing that they existed, and especially whether the
quantity increased as spring approached. Samples of water
from different ponds in various districts were therefore ex-
7

9 8 SCIENCE PROGRESS

amined by the following method. Three litres of the water
were filtered through an ordinary chemical filter and were then
evaporated to dryness over the water bath. The residue was
digested with 5 c.c. of hot organically pure NH 3 free distilled
water and filtered. To a tube containing 5 c.c. coefficient jelly

3 units of stain were added and 7 units of alkali, and the
total was made up to the necessary 10 c.c. by the addition of

4 c.c. of the sample to be examined (2). The tube was then
placed in a beaker of boiling water till the jelly had melted, and
the reagents mixed thoroughly with it. It was then boiled in the
bunsen till it frothed up, and a drop or two was poured on to a
glass slide, where it was allowed to set firmly. Some blood
was taken from the finger and mixed with an equal volume of
citrate solution (3 per cent. sod. citrate and 1 per cent. sod.
chloride) to dilute it, and a drop of this was placed on a cover
glass, which was at once put on to the jelly. The specimen was
then placed in the 37 C. incubator and allowed to remain there
for ten minutes. The coefficient of diffusion of human lym-
phocytes is 14, and it will be seen from the following equation
that this jelly should just stain their nuclei in ten minutes at
37 C. 3 S + 7 A + 7 h + t - (3 C + N) = 14. The slide was then
taken from the incubator and examined with the microscope.

If division figures were found in the majority of the lympho-
cytes, the pond was marked down as containing auxetics. In
order to determine the presence of kinetics, a tube of 5 c.c.
coefficient jelly had 5 units of stain added and 6 units of alkali,
the contents being made up to 10 c.c. with 3*9 c.c. of the sample.
Blood, as already described, was then placed on the jelly on a
slide and examined at room temperature (20 C), and if the
majority of the polymorphonuclear leucocytes showed exag-
gerated amoeboid movement the specimen was marked as con-
taining kinetics. Working in this manner, I examined samples
of water from twelve different ponds with the results shown in
the following table.

These results were sufficiently satisfactory to make me deter-
mine to carry out a somewhat tedious and prolonged research
into the question. I determined, therefore, to examine samples
from the same ponds monthly, and in order to ascertain whether
the substances in solution had any effect on the auxetics and
kinetics present, a chemical analysis of the water was made in
each case. One of the chief objects in this research has been

AWAKENING OF POND LIFE 99

to show that it is mainly by means of the auxetics and kinetics
present in the pond water that the dormant life is caused to
reawake in the spring. The following tables show the results
of the experiments. For convenience the names of the localities
of the ponds are omitted, and the numbers only given. The
first table will therefore serve as a key to the remainder. It
will be clearly seen from a consideration of these tables that
there is undoubtedly a gradual increase in the auxetics and
kinetics present as summer approaches. The increase in the
kinetics was much more marked, however, than that in the
auxetics, which often seemed to remain constant. The chemical
analyses were conducted in order to ascertain, wherever possible,
if light could be thrown on any rise or fall in the auxetics and
kinetics present. I originally intended to conduct these monthly
examinations for the whole year, but unfortunately, owing to
a press of other research work, I was unable to carry the
chemical analyses further than May, although the testing for
auxetics and kinetics was continued to the end of June, as was
also the examination for albuminoid ammonia. If the chemical
analyses are carefully examined, it will be seen that the tendency
of the albuminoid ammonia is to increase from January to May,
and this is exactly what the kinetics do.

Perhaps this fact is most strikingly brought out by means
of a curve, and if this is constructed it will be seen at once that
the kinetic curve rises and falls with that of the albuminoid
ammonia. Too much stress should not be laid on this point,
however, as on an examination of the tables it will be seen that
it is not always apparently the exact amount of albuminoid
ammonia in any given pond which determines the question
whether kinetics will or will not be present. Thus pond No. 1
showed traces of kinetics in January, the albuminoid ammonia
being 0*019, whilst pond No. 3 contained no kinetics this month,
although the albuminoid ammonia was 0'o8. It is evident,
therefore, that it is not the amount of albuminoid ammonia itself
which causes the kinetics to rise and fall, but something else
which, whilst producing kinetics, also influences the albuminoid
ammonia in an upward direction. Albuminoid ammonia, of
course, does not exist in water as such, but is a laboratory
product from the organic matter present in the water in solution.
The more organic matter in solution the higher will be the yield
of albuminoid ammonia obtained. Now in ponds, where as a

ioo SCIENCE PROGRESS

rule much decaying vegetable matter accumulates, the chief
factor in determining the amount of organic matter in solution
will be bacterial action in breaking up the complex and mostly
insoluble proteids into simpler bodies, many of which are
soluble. The ultimate tendency is for the proteins to be broken
up into nitrates, nitrites, and saline ammonia. These substances,
of course, will not yield albuminoid ammonia. This being so,
it is evident that the time when the albuminoid ammonia should
be largest in amount is when the bacteria are breaking up the
insoluble proteids into soluble ones, and^prior to their complete
disintegration. Probably at this time alkaloids of putrefaction
are formed, especially if the pond should contain much animal
matter, and alkaloids are all powerful kinetics. It is probable,
therefore, that the albuminoid ammonia is a criterion of bacterial
activity in the pond, a rise showing that a greater amount of
decomposition is going on, and consequently a greater kinetic
production. Thus although a pond containing o"oi9 parts per
100,000 of albuminoid ammonia may show traces of kinetics,
while another with a content of co8 shows none, the explanation
probably is that the former contains more animal matter than
the latter, which is probably a more effective producer of
kinetics. The kinetic curve, then, probably follows that of the
albuminoid ammonia, because the rise of this substance in any
sample from a given pond is a measure of the amount of the
bacterial activity in that pond.

The explanation of the gradual awakening of life in spring-
time now becomes intelligible. Auxetics are apparently nearly
always present, but the kinetics vary, being altogether absent
at times. During autumn leaves and other vegetable matter
fall into the ponds, while during the cold of winter there is also
undoubtedly a higher death-rate amongst the fauna, all of which
supply the organic material for the manufacture of auxetics and
augmentors (kinetics). Bacterial activity now comes slowly into
play, decomposing the organic matter and producing kinetics,
which probably accumulate for a time, and ultimately, by
augmenting the action of the auxetics, cause the reawaking of
the dormant life. Nor does the matter stop here, for what
applies to the pond almost certainly applies to the earth. The
dead leaves which are shed in autumn being gradually decom-
posed by bacteria, the soluble products are washed down into
the earth, to be slowly absorbed by the roots of plants, in which

AWAKENING OF POND LIFE

IOI

they stimulate development. As all cells possess a coefficient
of diffusion, so therefore will they take various times to absorb
the auxetics and kinetics supplied to them, and will therefore
complete their life cycles at different times, giving us a possible
explanation of the sequence observed in the vegetable kingdom.
It is possible, in fact probable, that other factors may also be
concerned, but I think there can be no doubt that owing to
bacterial action, kinetics are produced in larger quantities as
spring advances, and augmenting the action of the auxetics
cause a large increase in the development of all living matter.
It would therefore seem that death is essential for the due
maintenance of life, for as all natural auxetics are the products
of cytolysis there must inevitably be death to produce the
substances essential for the continuance and awakening of life.
In autumn and winter, therefore, when all nature seems dying,
we may picture the products of this death gradually being
absorbed finally to cause the resurrection in spring. 1

References

i. Drew, A. H., "Auxetic Action on the Spores of a new Species of Polytoma,"
Knowledge, March 19 13.

2. Ross, H. C, Induced Cell Reproduction and Cancer. (London, J. Murray, 1910.)

3. Cropper, J. W., and Drew, A. H., Researches into Induced Cell Reproduction

in Amcebce, The McFadden Researches. (London, J. Murray, March 1914.)

TABLE A
Preliminary Examination for Auxetics and Kinetics

Number
of Pond.

Situation of Pond.

Date of
Examination.

Auxetics.

Kinetics.

Horn Park, Lee, Kent .

20. II. 12

yes (slight)

yes (very faint)

Southend Village, Kent

23. II. 12

yes (trace)

yes (very faint)

Burntash Hill, Lee, Kent

24. II. 12

yes (good)

Bushey, near Watford, Herts

28. IO. 12

yes (good)

yes (feeble)

Keston, Kent

2. IO. 12

yes (good)

yes (fair)

Mitcham, Surrey .

4. IO. 12

Crofton Park, Kent

12. II. 12

Norbury, Surrey

15. II. 12

yes (trace)

Merryhill, near Watford, Herts

l8. IO. 12

yes (good)

yes (fair)

Watford, Herts

20. IO. 12

yes (good)

Harrow, Middlesex

30. II. 12

yes (fair)

Honor Oak, Surrey

26. II. 12

no (suspicious)

yes (very faint)

1 Since writing the above (3) it has been shown that the presence of a
ferment is probably necessary for an auxetic to act, the kinetics probably
activating the ferment ; hence the increase in decomposed vegetable matter
during autumn probably also supplies an extra amount of enzyme.

B
W
pq

t/3
u

in
U

—

H
Id
X

Ik
t/3

Q
55
O
Ph

8
*c

►J
a

55
O

^-*s.

^■*

*T3

i^l

O
O

w -^

tn CD

01 " —
S~.

'£

, ,

"T3

.£5

-c

•a

a
M

c
fl

c
B

in
01

tn
01

in tfl
0i ""

tn
Oi

— >

tfl

i-n

, .

>-»

^_,

'*-\

4-*

*-»

i^t

i~>

^-s

o
3$

b/1

o
tfl

>» '

n — •*

— *

tfi

tfl

a
a

— >

'•J

tfl

tfi

>■>

r~»

>*»

'^~>

K~»

**y

>*.

•5"

'O*

•5"

-5 s

-o"

-a

tfl

-£5

$£

_tfl

tfi

tfl

tfi

>-.

>■%

>^»

>»

>-.

'***>

>-.

tn"

'£

t/i

t/)

c/1

tfi

3
<

>~>

>»

i^l

»>*

s-i

^__^

.— .

*^\

T3
O

T3
O
O

^tfl

T3
O
O

CJO

o
o
So

b4
3

-— _^
01 ^

^§
in tfl

in tfl

o
o
_tfl

T3
O
O

tfi

tfl

tfi

tfl

>-.

tfl

3
<

crt

>-,

>-.

»-»

^_^

"a?

"o?
o

>-.

-5"

-d"

O
O

tfl

'IT

— ^-^

i§

1M
-4-1

> o

bfl

tfl

^ c

C/)

tn ofl

t/3

■fi

>-,

>»

tn
u

'£

tfi

t/:

>■

>-»

t>~.

>»

>-,

S»

-*— i

1-1

O
O
_tfl

Efl

3
u

>-.

>»

>->

'oT

_, ,

4-1

c
c5

jy
>«

t/i

tfl

<fi

>">

&-■

>■»

>-.

>*»

T3
O

'w*

fc4

O
Cfl

fc«

• »*

t/)

>-.

t»l

>->

in
U

_01

-*-(

-5"

•5"

■—1

^QJ

•Si

tfl

— *

- f

1 — '

^— *

°*~*

*■•*

" — '

* — "

tfi

t/i

tfl

<L>

;*>

>»

>-.

u
4)

•a

« c

u-l

«>.

!-•

—

►H

AWAKENING OF POND LIFE

103

JANUARY 1913
All Figures are in Parts per 100,000

No.

Total

Solids.

Loss on
Ignition.

Chlorides.

Nitrates.

Nitrites.

Total
Hardness.

Saline
NH 3 .

Albuminoid
NH,.

6-3

8'4

4*9

trace

45"i

•12

'019

4*i

nil

28-2

•03

•013

4'02

6-5

nil

38-8

•08

4*3

3'9

nil

34"2

'05

3-8

6-2

trace

27"I

■13

3«

3-01

4-5

trace

28-4

■13

"20

2-6

6-4

•42

nil

153

'22

•81

nil

28-2

•l6

•08

2"5

5'5

•3

nil

I4'2

•8l

'53

4*3

IO"2

nil

28-8

i-6 5

•80

5'2

I2"3

i'3

trace

48-3

1-51

•85

3-8

5'8

•85

nil

24-5

•5

•62

FEBRUARY 1913

No.

Total
Solids.

Loss on
Ignition.

Chlorides.

Nitrates.

Nitrites.

Total
Hardness.

Saline
NH,.

Albuminoid

NH,.

5-8

8'8

3'6

trace

42-5

'14

•028

4-6

5'3

•64

nil

30-2

•05

'019

4'i

5*5

'51

nil

34'°

•8

•06

5'3

4-8

•42

nil

32'4

•18

•08

3'2

5'2

*52

nil

25-8

'13

•16

3"i

6-3

'25

nil

24'3

*I2

'23

6-8

'34

nil

i6"4

'25

'19

4*5

5'i

•85

trace

28-5

•13

"IO

2'3

6-4

•22

nil

i4'5

•68

•48

5'2

12-3

'55

nil

25*6

1 "42

•92

65.

7'i

12-5

i'5

trace

46*2

i"3i

'95

4-8

•64

nil

251

•42

•63

MARCH

1913

No.

Total
Solids.

Loss on
Ignition.

Chlorides.

Nitrates.

Nitrites.

Total
Hardness.

Saline
NH 3 .

Albuminoid
NH,.

76-5

5'2

7'5

2'4

nil

40^

•12

•035

43'2

4'3

6-4

•6l

nil

32'6

•08

•02I

44'3

5*4

'49

trace

33'8

'54

•08

45'5

4'4

5'5

'35

nil

36-3

I'2I

"12

36-8

4'8

•63

nil

25'5

•25

•l8

38'2

3'i

6-i

•28

nil

26"I

•19

•26

28-1

3'3

6'5

•25

nil

16-8

"20

•15

46-3

4'2

4'8

•65

trace

25-4

•15

'12

25*2

6'5

•31

nil

16-1

•48

•51

6o"i

4'8

10-5

•60

nil

33'2

ri8

58'4

6'5

9-6

•85

trace

40' 1

I'OI

112

46-3

4'5

501

'55

trace

24'3

'45

•69

104

SCIENCE PROGRESS

APRIL 1913
All Figures are in Parts per 100,000

No.

Total
Solids.

Loss on
Ignition.

Chlorides.

Nitrates.

Nitrites.

Total
•Hardness.

Saline
NH 3 .

Albuminoid
NH 3 .

74'5

5-6

6-4

nil

38-8

'24

•058

40*2

3'8

6-6

'52

nil

3o"4

•09

•032

40-5

3'2

4-5

■42

nil

32- 1

'55

•09

46*1

3" 5

5-6

'39

nil

36-8

i'35

•l8

38-3

2-8

4*5

nil

26"2

•36

'22

35'2

2*2

6-2

•15

nil

24*1

'34

•28

3°'4

2'5

6-6

'20

nil

16-5

'30

•21

45"3

3-8

4'5

•51

trace

24'3

•18

'IS

28-5

2'3

6-8

*24

nil

16-5

•50

•55

55'4

4' 1

8-4

•55

trace

30' 5

I'OI

•96

52-1

3-6

8-5

•80

nil

35'8

I'20

1 "34

45'2

3-8

5*3

•56

nil

23"5

•52

•81

MAY 1913

No.

Total
Solids.

Loss on
Ignition.

Chlorides.

Nitrates.

Nitrites.

Total
Hardness.

Saline
NH 3 .

Albuminoid

NHj.

JO'2

4"3

5*5

I"42

trace

36"3

'25

•062

384

3-6

5-8

•42

nil

25"2

'IO

•051

4°'9

—

4'2

•42

nil

30-I

•46

•09

47'2

—

6-i

•28

nil

35*5

T28

•21

3 6 '4

—

6-3

•85

nil

25-4

•45

•26

36- 1

—

6-8

•18

nil

25'5

•42

'31

32'5

—

5'5

'25

nil

16-8

'34

•24

46-3

—

5'2

•45

nil

25-1

"22

•18

3°"2

3'i

6'6

•28

nil

15-2

•50

•55

52-4

4'i

7'3

'41

nil

26-8

I'2I

I'OI

54*3

—

I'20

trace

36- 1

I'20

1*3

42*6

5'5

•84

nil

23-8

•68

•92

ALBUMINOID AMMONIA IN PARTS PER 100,000

No.

January.

Februar3 T .

March.

April.

May.

June.

July-

•OI9

•028

'°35

•058

"062

•060

•12

•013

•019

"021

•032

•051

•052

•09

•08

•06

•08

•09

•08

'12

"OS

•08

*I2

•l8

*2I

•24

# 20

'"3

•l6

•18

"22

•26

'22

•18

•20

■23

•26

•28

•31

•30

•25

•14

''9

'*5

*2I

•24

'20

•15

•08

"IO

•12

'"5

•18

•15

# 20

'S3

•48

•51

•55

"55

'45

•48

•80

•92

I'lO

•96

roi

•92

•80

•85

'95

I'I2

i'34

1 "3°

■50

•65

•62

•63

•69

•81

•92

•60

•65

SCIENTIFIC RESEARCH AND THE SEA

FISHERIES

Bv J. T. JENKINS, D.Sc, Ph.D.,

Superintendent, Lancashire and Western Sea Fisheries

During the last few years no less than three Departmental
Committees have inquired into and reported on the facilities
for scientific research into problems concerning the sea fisheries
of these islands. There was first of all the Committee on
Ichthyological Research of 1902, then the Committee on Fishery
Investigations of 1908, and finally the Committee appointed by
Mr. Runciman in 191 3 to " advise the Board (of Agriculture and
Fisheries) on questions relating to the elucidation through
scientific research of problems affecting fisheries."

The recent publication of the " first report " of the last
Committee raises anew the whole question of the State aid of
scientific investigation of the fisheries. The recommendations
of the two former Committees are now of historical interest
only, but in order to understand properly the present position
it is necessary to consider briefly the position of scientific
fishery research at the time these Committees reported. No
one cognisant of the facts can fail to be struck with the
enormous growth of marine biological research subsidised by
the State ostensibly because it throws light on problems con-
cerning the future of our fisheries.

The central authorities for fishery administration in the
three kingdoms are in England the Board of Agriculture and
Fisheries, in Scotland the Fishery Board, and in Ireland the
Department of Agriculture and Technical Instruction. In
England and Wales there are also local administrative authorities,
usually Joint Committees of maritime County and County
Borough Councils. In 1902, when the Committee on Ichthyolo-
gical Research reported, the central fishery authority for England
and Wales (then the Board of Trade) practically undertook no
scientific fishery research, although they collected the com-

105

I0 r, SCIENCE PROGRESS

mercial fishery statistics, for which a special grant was made
by the Treasury. Research work was undertaken by a few of
the district committees and by one or two scientific bodies, for
instance, the Lancashire and Western Fisheries Committee and
the Marine Biological Association, the latter body being the
only one in England and Wales at that time in receipt of State
aid in connection with fisheries work.

In Scotland and Ireland scientific research was undertaken
at the cost of the State by the central fisheries authorities for
those countries. As the result of their deliberations the Com-
mittee of 1902 made certain recommendations, of which the
following were the most important. They stated it would be
necessary for the State to provide funds for the collection of
statistics from trawlers and the examination of material at the
ports, for the provision of the necessary assistants at the marine
laboratories already in existence, for the provision and main-
tenance of three research steamers, and for putting the staff in
Scotland and Ireland on a permanent basis.

Between 1902 and the publication of the report of the
Committee on Fishery Investigations of 1908 a considerable
advance was made in the provision of fishery research. An
international council for the exploration of the north and
neighbouring seas was established as the result of international
conferences held at Stockholm in 1899 and Christiania in 1901,
to consider programmes for the investigation of the sea by
scientific inquiry with a view to promoting and improving the
fisheries through international agreements. The participating
countries were Great Britain, Denmark, Germany, Holland,
Norway, Russia, and Sweden, with (at the second conference)
Belgium and Finland. The total expenditure incurred by Great
Britain up to December 31, 1913, on the international investiga-
tion of the North Sea amounted to £154,919, exclusive of the
cost of printing the reports.

In most other respects the position of the various authorities
engaged in fishery research was pretty much the same in 1908
that it had been in 1902.

The Committee of 1908 recommended the establishment of
a Central Council for the United Kingdom which should have
control of public funds for fishery investigations of a national
and international character. They also recommended the
strengthening of the Board of Agriculture and Fisheries as

SEA FISHERIES 107

the Central Fishery Authority for England and Wales, and the
provision of additional funds to the Board for the encouragement
of local work ; the continuance of adequate provision to the
Fishery Board for Scotland for local scientific research ; the
continuance of international co-operation in scientific and
statistical investigations upon a definite and permanent basis ;
and finally, the continuance of the annual grant of £1,000 to
the Marine Biological Association of the United Kingdom.

The chief difference between the position in 1908 as com-
pared with 1902 was that the Government were expending
about £13,000 per annum on the international investigations.
In the Civil Service estimates for 1907-8 we find under the
heading of " North Sea Fisheries Investigation " an amount of
£12,500, being the sixth instalment on account of expenditure
in connection with the international scheme for investigating
problems concerning the fisheries of the North Sea and adjacent
waters. The agents of the Government for the purposes of
these investigations were in Scotland the Fishery Board, and
in England the Marine Biological Association, to each of whom
the sum of £5,500 was payable annually. In addition the
annual sum of £1,250 was paid as a contribution to the Central
Bureau which had been established at Copenhagen. The fact
that the Board of Agriculture and Fisheries, the central
authority for Fisheries in England, had been ignored in the
allocation of these grants was a cause of considerable friction
between the Board and the Association, as will be seen from a
study of the evidence given before the Committee of 1908.

Ultimately the Board gained the victory, and they took over
the control of England's share of the international investigations
in 1910.

The next important event in the history of scientific fishery
research was the passing of the Development and Road Im-
provement Funds Act of 1909. According to this Act the sum
of £500,000 was to be set aside for five years for certain
purposes, amongst which was " the development and improve-
ment of the Fisheries." Applications for funds for this purpose
were to be made in writing to the Treasury, who would refer
the matter to the Development Commissioners for report.

In the first annual report of the Development Commissioners
dated July 191 1, there is one paragraph which refers to the
fisheries, viz., " In respect to the development and improve-

,o8 SCIENCE PROGRESS

mcnt of fisheries proper, the Commissioners have received no
applications. They learned some time ago that not inconsider-
able applications for advances for such purposes had been
made to the Treasury and referred to the Government Depart-
ment or Departments concerned."

The fact is that the Board of Agriculture and Fisheries
were quite unprepared with a scheme for the development of
the fisheries, and they deliberately hung up schemes prepared
by local authorities so that they might prepare and put forward
their own scheme first. In the meanwhile, of course, they had
the opportunity of considering the schemes forwarded by the
local authorities. In one instance an application submitted by a
local authority in May 1910 was definitely replied to in March
1912.

In the meantime the " comprehensive scheme " prepared by
the Board of Agriculture and Fisheries and submitted by them
to the Development Commissioners was rejected by the latter
body as entirely unsuitable. It is not an easy matter to get
particulars of this scheme pour rire of the Board. In fact it
is extremely difficult to get authentic information as to its
real parents ; to quote Shakespeare we might " laugh to think
that babe a bastard."

Practically every detail of the application was ruled out by
the Commissioners. The Board's application was for a loan
of £50,000 and an annual grant for the purpose of putting on
vessels to patrol waters at present not properly protected, and
they also applied for funds for what was euphemistically called
" a Special Commission to inquire into the grievances of the
inshore fishermen." It was obvious to any one acquainted with
the terms of the Development Act that such an absurd scheme
was bound to be rejected, since the Development Fund is not
properly available for enabling authorities to perform their
statutory duties, and neither can it be utilised to increase the
salaries of permanent officials.

The comprehensive scheme of the Board having been rejected,
the whole future of scientific fishery research was jeopardised,
but the Development Commissioners met the difficulty by
making interim grants.

The second report of the Commissioners, published in
September 191 2, contains some reference to these matters. We
learn that the Board's application was considered by the

SEA FISHERIES 109

Commissioners, but as they understood that a number of
applications relating to fishery matters had been addressed to
the Treasury by scientific bodies, local fishery committees, and
other authorities, and were awaiting report by the Board, the
Commissioners thought it desirable to obtain these before pro-
ceeding with the consideration of the Board's scheme. Not
being able to approve of the Board's scheme, they suggested
to the Board (after the Commissioners' meeting in September
191 1) that its application should take the form of a compre-
hensive scheme, prepared in consultation with the Scottish and
Irish authorities, for the acquisition of further knowledge of
the fisheries of the United Kingdom. Interim grants were
recommended to the following bodies : The Lancashire and
Western Local Fisheries Committee, £1,640 ; the Marine Bio-
logical Association, £500 ; the Liverpool Marine Biological
Committee, £100; and the Eastern Local Fisheries Committee
and the University College of Wales, Aberystwyth, £50 each.
Of the £78,000 asked for by the Board the sum of £4,100 was
granted, £600 for research on the lobster fisheries and £3,500
in aid of the general research work conducted by the Board.

In January 1913 Mr. Runciman appointed a Committee to
advise the Board of Agriculture and Fisheries on matters con-
nected with scientific fishery research. While this Committee
was considering the situation the Development Commissioners
issued their third annual report (in August 191 3). In April 1912
the Board submitted to the Commissioners in outline a proposal
for the provision of three research steamers which were then
estimated to cost £10,000 each, and to consider annual grants
of £10,000 for maintenance and £6,500 for the collection and
study of material. The estimate of capital cost has since risen
to £16,000 for each steamer. This, it will be noted, is an entirely
different scheme to that first submitted by the Board. Possibly
by now some one in the Department had looked up the pro-
visions of the Development Act ! The Commissioners agreed
in principle to this scheme of the Board's, but thought it best to
defer a grant for the construction or acquisition of the vessels
until the scheme for which they are primarily required has
been settled by consultation among the fishery authorities of
the United Kingdom.

In January 1913 the Commissioners received the Board's
application for the year 1913-14. The Board explained that

no SCIENCE PROGRESS

they would not be in a position to submit the general scheme
(first asked for in September 191 1) before the expiration of the
period for which the interim advances had been granted, i.e.
March 1913, and they asked that the interim grants should be
continued for another year, with an additional amount of
£1,500 for the Board's research vessel.

In January I9i4the Scientific Research Committee appointed
by Mr. Runciman twelve months previously reported, and
shortly afterwards information leaked out that a comprehensive
scheme had been prepared by the Board acting in conjunction
with the Scottish and Irish authorities, and was presumably
under consideration by the Commissioners. The Board now
ask for £60,000 for the first year, and £25,050 per annum after-
wards. Of this only £6,000 per annum is to be devoted to all
the local authorities in England and Wales, the remainder
being absorbed by the Board. This scheme, so far as it relates
to England and Wales, has been prepared without the local
authorities being in any way consulted. In addition to the
three research steamers asked for by the Board in April 191 2,
two motor-boats are now considered to be necessary. The
estimate of maintenance of the steamers has now gone up to
£15,000 (from £10,000). One motor-boat is to cost £1,500, the
other £1,000, and in each case the maintenance is fixed at £750
annually. Presumably this enormous expenditure is additional
to that already incurred by the Board in respect to England's
share in the North Sea fisheries international investigations,
which amounts in the Civil Service Estimates for the year
ending March 31, 1915, to £7,530. No mention is made in the
estimates that any portion of this sum is repayable from the
Development Fund, though in other cases " Fishery Develop-
ment " grants in aid of research work and investigations con-
ducted by the Board amounting to a total of £10,905 are so
repayable, except as regards £1,105. If» therefore, the scheme
of the Board be adopted by the Commissioners, the Board will
spend during the first year's working of the scheme no less
than £68,635, and afterwards about £33,000 a year. The bulk
of this expenditure, in fact all except a small sum, is new.
Most of the proposals are quite unjustifiable, and little or no
attempt has been made to utilise existing organisations. The
Marine Biological Association has a magnificent marine
laboratory at Plymouth, and there are similar institutions at

SEA FISHERIES in

Cullercoats, Piel, Liverpool, and Aberystwyth. Several of the
District Committees have steamers which could be utilised,
either partly or entirely, for observations at sea. For the
assistance of all these bodies, for the provision of research for
the development of the salmon and fresh-water fisheries, and
for grants to local institutions for experimental work on and in
connection with trade products, a beggarly £6,000 a year is
proposed. But what is the worst feature in this preposterous
scheme of the Board's is the manner in which the local
authorities have been ignored in its preparation. One would
have thought that the rejection of the Board's fatuous scheme
of 191 1 would have indicated the advisability of consulting
those authorities having practical experience in the working of
detailed schemes of fishery research. Fortunately Lord Richard
Cavendish, the Chairman of the Development Commission, is a
man of considerable acumen, and indications are not wanting
that steps are being taken by the local authorities to enlighten
him as to the true significance of the Board's scheme. When
promotion in the Civil Service is dependent on the nepotic
vagaries of peripatetic Cabinet Ministers, it becomes imperative
in the public interest closely to scrutinise schemes which
involve the expenditure of large sums of public money.

SOME RECENT WORK ON PLANT

OXIDASES

By W. R. G. ATKINS, M.A., Sc.B., F.I.C.,

Assistant to the Professor of Botany, Trinity College, Dublin

In the last ten years the attention of plant physiologists has
been largely directed to the study of chemical reactions which
take place in the individual cells which go to make up tissues.
By the application of suitable reagents it has been found possible
to examine many of these qualitatively, and to some extent
quantitatively. In such researches the formation of precipitates,
amorphous or crystalline, and the production of colour reactions
within the cells is examined with the aid of the microscope.
Frequently it has happened that one and the same tissue has
afforded material for workers with entirely different aims in
view. For example, researches on carbohydrate formation and
solution may be undertaken by one, while another may examine
the processes of oxidation occurring in similar cells. Yet though
these may seem very different phenomena, they are really closely
connected as constituting together important parts of the life
of the cell, the elucidation of which in its entirety is the aim of
the physiologist.

Many of these changes can be brought about equally well
outside the living cell, though the production of some of them
in vitro has as yet baffled the chemist. But the methods by
which they are effected in the organism are much more direct,
and dispense with the high temperatures and concentrations of
strong acids of which the chemist has to make use. Accord-
ingly the study of enzymes, as the substances produced by the
cells to bring about such specific chemical changes are termed,
has become one of the most important branches of biology.

Numerous researches have been directed to the unravelling
of the complicated inter-relations of the mechanism by which
the fundamental need of oxygen is supplied, and it has been
shown that enzymes termed oxidases are concerned in the
utilisation of this gas.

112

SOME RECENT WORK ON PLANT OXIDASES 113

It is with some of the more recent results of the study of
the oxidases that this paper proposes to deal. The subject as
it was known up to 1910 has been exhaustively treated of by
Kastle, 1 also by Clark, 2 and Czapek, 3 and to these publications
the author is much indebted. 4

The Nature of Plant Oxidases

On the whole the substances which effect oxidations in plants
have the properties of enzymes, though their behaviour is in
some ways peculiar. The usual routine adopted in deciding
whether a given reaction is enzymic or an ordinary chemical
change is to boil the solution. If the reaction is no longer
brought about it is concluded that it is enzymic, its cessation
being due to the destruction of a thermolabile oxidising agent.
But enzymes have two other very important characteristics,
firstly, that a small quantity of the enzyme brings about a
relatively enormous transformation of the substrate, and secondly,
that the rate of this change is proportional to the amount of
enzyme present (provided the substrate is in large excess),
though the total amount transformed is independent of it if a
sufficient time be allowed to elapse. It may be added that
enzymes are colloidal, and the reactions they bring about or
catalyse are in many cases proved to be reversible, the point of
equilibrium being usually very near that of complete change in
one direction. Furthermore their action is as a rule specific,
one enzyme only acting on one substrate, or on one class of
substrates, and may in many cases be inhibited entirely, or
reduced in velocity by very minute quantities of paralysors.

Now the oxidising substances of plants are destroyed by
heat, though in some cases they may be formed afresh within

1 J. H. Kastle, Bull. No. 59, Hyg. Lab. U.S. Pub. Health and Mar.-Hosp.
Serv. Wash. 19 10.

2 E. D. Clark, Dissertation, Columbia Univ. 1910 (Eschenbach Co., Easton,
Pa.).

3 Czapek, Ergebnisse d. Physiol. 1910, 9, 587-613.

4 I have followed the custom of the American authors, and of Fowler {Bacterio-
logical and E7izyme Chemistry, Arnold, London, 191 1), Moore, and Whitley, in
writing " oxidase " rather than " oxydase," to denote the enzyme that splits up a
(per)oxide. The spelling " oxydase " has been taken directly from the French, in
which both " oxygen " and " oxydant " retain the letter " y." It seems an un-
desirable anomaly to spell " peroxide " with " i " and " peroxydase " with " y " as
is done at present. " Oxygenase," the enzyme which splits up molecular oxygen,
if such an enzyme exists, is of course correctly spelt with "y."

,, 4 SCIENCE PROGRESS

a couple of hours from thermostable zymogens, as has been
shown by Woods ' in the case of the oxidase of tobacco leaves.
It is remarkable, however, that no other workers have as yet
been able to find this zymogen. That they are colloidal and
can be precipitated from aqueous solution by the addition of
alcohol has also been shown.

The quantitative estimation of oxidases and of their rate of
action presents many difficulties. Among the most successful
attempts in this direction may be mentioned those of Chodat
and Bach, 2 who examined the action of peroxidase upon a
mixture of pyrogallol and hydrogen peroxide by weighing the
purpurogallin formed under standard conditions. Their results
showed that the peroxidase and peroxide take part in the
reaction in a definite ratio, and that the weight of purpurogallin
produced is proportional to the peroxidase. The above authors
also devised a volumetric method. However, the most funda-
mental quantity to measure seems to be the amount of oxygen
absorbed, and this Foa 3 and Mathews 4 have done and Bunzel 6
more recently with an elaborate apparatus and many necessary
precautions previously omitted. Bunzel, too, finds that the
amount of chemical change is directly proportional to the con-
centration of the oxidase present, and concludes that the typical
plant oxidase with which he worked " is not an enzyme in the
customary sense of the word, but rather a substance entering
directly into the reaction, and being destroyed in the course
of the same." He proposes as a unit to express the oxidase
content of a plant juice " a solution of such a strength that one
litre of it will be capable of bringing about the consumption by
pyrogallol of the equivalent of one gram of hydrogen — i.e. a unit
of eight grams of oxygen." It seems likely that much valuable
knowledge will be gained from Bunzel's systematic quantitative
researches at present in progress.

Before going further a distinction must be drawn between
the terms oxidase and peroxidase. Originally those tissues
which could bring about oxidations of natural chromogens or
of artificial ones such as guaiacum resin, benzidine, a-naphthol

1 Woods, Bull. No. 18, U.S. Dept. of Agric. 1902.

3 Chodat and Bach, Chem. Ber. 1904, 37, 1342.
5 Foa, Biochem. Zeitschr. 1908, 11, 382.

4 Mathews, A. Y.,Journ. Biol. Chem. 1909, 6, 3.

5 Bunzel, H. H., Bull. No. 238, Bureau of Plant Industry, U.S. Dept. of Agric.

SOME RECENT WORK ON PLANT OXIDASES 115

or pyrogallol, were said to contain an oxidase, whilst those
which required the addition of a peroxide such as hydrogen
peroxide or a spontaneously oxidised essential oil were described
as containing a peroxidase. The view that an oxidase consisted
of a peroxidase and a naturally occurring peroxide was put
forward by Kastle and Lcevenhart, 1 and has gained very general
acceptance. Keeble and Armstrong 2 record that in certain
flowers the organic peroxide accumulates during darkness, so
that apparently the tissues contain oxidase at one time and per-
oxidase at another. The author's own 3 observations on foliage
leaves also point to the variability of the quantity of the peroxide
in any tissue. At present it is usual to refer to the " direct "
oxidase action, or to the "indirect" action, when the addition
of a peroxide is required to bring about oxidation. Strictly
speaking it would be more correct to refer to both as peroxidase
actions, for the essential is that a peroxide is split up and
oxygen derived from it is transferred to an easily oxidisable
substance. That hydrogen peroxide does not occur in any
appreciable quantity in the tissues is proved by the almost
universal presence of catalase, an enzyme which decomposes
this substance, but does not attack the closely related ethyl
hydroperoxide or any other peroxide, so far as is known.

How far the oxidases are specific in their action seems to
be in doubt. Five different oxidases at least have been described
as occurring, or rather five different classes of oxidases, viz. lac-
cases, tyrosinases, alcoholases, purine oxidases, and aldehydases.
The laccases or phenolases which act on many phenols and are
very widely distributed in plants, and the tyrosinases which
act on tyrosin or polypeptides containing tyrosin to produce
a body which further reacts with amino-acids yielding dark-
coloured pigments termed melanins, as shown by Abderhalden
and Guggenheim. 4 An example of the alcoholases is furnished
by the enzyme which converts ethyl alcohol into acetic acid and
is found in certain bacteria. The purine oxidases have been
extracted so far from animal tissues only, and the existence of
the aldehydases is still hypothetical.

1 Kastle and Lcevenhart, Amer. Chem.Journ. 1901, 26, 539.

3 Keeble and Armstrong, Journ. Genetics, 1912, 2, No. 3, 277.

5 Atkins, W. R. G., Set. Proc. R. Dubl. Soc. 191 3, U(N.S.), 144.

4 Abderhalden and Guggenheim, Hoppe-Seylers Zeitschr. f. physiol. Chem.
1908, 54, 331.

Il6 SCIENCE PROGRESS

It should be mentioned that the production of the organic
peroxides before alluded to is by some held to be the work of
a special enzyme oxygenase.

It has been pointed out by Bertrand ' that the aromatic
monophenols and monamins are not easily oxidised by laccase,
but that substances which it readily attacks are all members
of the benzene series containing hydroxyl or amino groups
in the ortho or para positions.

Researches in plant physiology deal almost entirely with
the two classes of enzyme at the head of the list ; there is
at present no proof that the laccase or tyrosinase from one
species is identical with that from another, though they may
produce certain colour reactions in common. This important
question is being investigated by Bunzel. The part played
by inhibitors in effecting apparent specific action by oxidases
will be treated of later on.

For further information, concerning the preparation of
artificial oxidases, the effect of small quantities of acids, alkalis
and manganese salts upon the activity of oxidases, as well
as for discussions of the identity of Medicago-oxidase with a
mixture of calcium salts of organic hydroxy acids including
glycollic, citric, malic and mesoxalic, the reader is referred
to the monographs by Kastle and by Clark, and to Euler's
General Chemistry of the Enzymes. 11

The Physiological Functions of the Plant Oxidases

Respiration.— It is a matter of common observation that
leaves when killed by frost or by severance from the tree
frequently assume a brown, black or red colour, and that
local injuries such as punctures by insects or by parasitic
iungi take on similar shades of pigmentation. The conspicuous
purple red spots appearing on blackberry leaves in autumn
are a good example of the effect of the last-mentioned cause,
being brought about by the disorders in metabolism due to
the attack of Phragmidium violaceum, the teleutospores of which
are always found as black specks on the lower surfaces of
leaves which show such discolorations.

Numerous investigators have established the fact that these

1 Bertrand, C. R. 1896, 122, 1132.
* Wiley & Sons, New York, 1912.

SOME RECENT WORK ON PLANT OXIDASES 117

colours are produced by the action of oxidases upon colourless
sap-soluble chromogens, the latter probably arising by the
hydrolysis of a complex glucoside. Much work has been done
by Palladin ' and his pupils in examining the distribution of
such chromogens, which they believe to be of fundamental
importance in respiration. They conceived of this process
as a taking in of oxygen by a readily oxidisable substance to
form a peroxide. The latter is then split up by oxidase,
yielding its oxygen for the oxidation of reducing substances
elaborated by the protoplasm.

More recently Palladin 2 has brought forward the view that
the respiration of a substance such as glucose is a hydrolytic
oxidation, whereby the carbon is oxidised anaerobically to
carbon dioxide, and the hydrogen thus set free combines with
a respiratory pigment, reducing it to a colourless chromogen.
In the following aerobic stage oxygen is absorbed, with the
production of water and the pigment. These processes are
shown in the following equations :

1. Anaerobic stage :

C,H 12 6 + 6H 2 + 12R = 6C0 2 + I2RH,

Glucose. Water. Respiratory Carbon Chromogen.

pigment. dioxide.

2. Aerobic stage :

i2RH 2 + 60 2 = I2H 2 + 12R.

An interesting example of the action of a respiratory enzyme
obtained from the spadix of an Aroid has lately been studied
by Weevers. 3 The heat-evolution in the spadix had long
been known, as had also the facts that it' arose from the
oxidation of sugars and that the products were carbon dioxide
and organic acids. Weevers established that oxidation could
be carried out actively by the enzyme in air or in an atmos-
phere of hydrogen. Glucose was decomposed with the forma-
tion of carbonic and citric acids, but without any production
of alcohol even when the reaction took place in hydrogen.
He concludes, therefore, that the enzyme cannot be a zymase,
for in addition to the absence of alcohol the presence of an
organic acid was demonstrated.

1 Palladin, Ber. d. deut. Bot. Gesell., 1908, 26, 378, 389.

3 Ibid. 19 1 3, 31, 80.

s Weevers, Kon. Akad. v. Wetenschappen, Amsterdam, 191 1, Oct. 28.

,,S SCIENCE PROGRESS

With regard to the chromogens it is found that the quantity
of the autoxidised materials normally present is insufficient to
impart a colour to the cells which are continuously manu-
facturing reducing substances. But upon the death of the
cells or upon the shortage of supplies of materials necessary
for metabolism, the activity of the oxidase is unchecked and
many changes are effected, among them being the production
of sap-soluble pigments from the chromogens. The latter may
be tested for by pressing some sap from the organ under
examination. If this appears brown it is invariably found
that an oxidase is present, together with organic peroxide
and chromogen. If no colour is produced it must be further
tested by the addition of hydrogen peroxide. The darkening
of the sap then takes place if it contains a chromogen, unless
oxidase action is hindered by an inhibitor. In this eventuality
a considerable amount of an oxidase preparation has also to
be mixed with the sap in order to ascertain whether it will
darken or not.

Distribution of Oxidases in Plants. — In the above paragraph
it has been assumed that oxidase is present, to some degree
at least, in every vegetable cell, and this I believe to be the
case in the large majority of land plants. Bourquelot and
Bertrand, 1 Zellner, 2 Pringsheim, 3 Kastle, 4 and others, have
shown that phenolases and tyrosinases are of almost universal
occurrence in fungi. Clark 5 tested a large number of groups
of flowering plants and pteridophytes, and has found pheno-
lases to be of very general occurrence : in certain strongly
acid saps, however, he failed to detect any oxidase ; Moore and
Whitley 6 also noted their absence from the pulp of lemons,
limes, and oranges.

Some cases are met with in which the usual tests such
as guaiacum resin, benzidine, and a-naphthol fail to give any
reaction even after the addition of hydrogen peroxide. In
such tissues an inhibitor is usually present. For example,

1 Bourquelot and Bertrand, Compt. Rend. Soc. Biol. 1895, 47, 582, and Bull.
Soc. My co I. de France, 1896, 12, 18.

2 Zellner, Die Chcmie der Hohcren Pilze, 209, Leipzig, 1907.

3 Pringsheim, Zcitschr. physiol. Chem. 1909, 62, 386.

4 Kastle, J. H., Bull. No. 26, Hyg. Lab. U.S. Pub. Health & Mar.-Hosp. Sew.
Wash., 1906.

5 Clark, E. D., loc. cit.

' Moore and Whitley, Biochcm. Journ. 1909, 4, 136.

SOME RECENT WORK ON PLANT OXIDASES 119

the young leaves of the Virginian creeper (Vitis Veitchii) are
red, and give the oxidase reactions. The mature leaves are
green and give no oxidase reactions ; but in them tannin
is present, which is known to act as an inhibitor. Finally,
in autumn the leaves again become red, yield positive results
with oxidase reagents, and contain no tannin. Another instance
examined by the author l is the behaviour of the leaves of Iris
germanica, which contain reducing substances in quantity,
and fail to reveal oxidases in the pressed sap, though micro-
scopic examination of sections treated with the usual reagents
demonstrates their presence in certain tissues. Moreover, on
pouring the sap into alcohol a precipitate is obtained. When
this is well washed with spirit and redissolved in water, it
is found to give the guaiacum reaction for an oxidase. The
inhibitor here cannot be an anti-enzyme of colloidal nature,
for after dialysis of the sap in presence of toluene a direct
oxidase reaction can be obtained with guaiacum. In Pteris
aquilina leaf sap too, removal of an inhibitor by dialysis
permitted the detection of an indirect oxidase reaction.

In the course of their researches on the production of antho-
cyan pigments, Keeble and Armstrong 2 showed that certain
white flowers owed their colour to the presence of an inhibitor
which prevented the action of an oxidase. These authors
observed that treatment with dilute hydrocyanic acid and subse-
quent thorough washing neutralised the action of the inhibitor,
so that the oxidase now afforded the usual reactions. I have
also found their method effective with the flowers of a number
of varieties of Iris, 3 and with the tissues of certain fruits. Thus
it is clear that in numerous instances the occurrence of the
oxidase may be demonstrated by a variation of the usual pro-
cedure, and so negative results must be accepted with caution.

With regard to the oxidases of the fresh water and marine
algae, however, but little is known. It has recently been shown
by the author 4 that oxidases of the phenolase type at least are
very infrequently met with in this class of plants. Out of about
thirty species of the green, brown and red marine algae only six
were found to contain oxidases. Brown algae of the Laminaria

1 Atkins, W. R. G., loc. cit.

3 Keeble and Armstrong, Proc. R. Soc. 191 2, 85 B, 214.

3 Atkins, W. R. G., Set. Proc. R. Dubl. Soc. 1914, 14 (N.S.), No. 8, 157.

4 Ibid. 1914, 14(N.S.), No. 11, 199.

I2 o SCIENCE PROGRESS

class were indeed the only ones to give well-marked indirect
reactions with guaiacum resin. Nevertheless most algae tested
give a colour with the benzidine reagent, more especially in their
cell walls. But this must not be regarded as always indicating
an oxidase, for in some of the cases most thoroughly examined —
certain of the green algae — the blue colour was found to be pro-
duced at an equally rapid rate immediately after boiling. These
investigations on algae are at present being continued.

The widespread distribution of oxidases and chromogens in
land plants shows that Palladin's views on respiration are of
very wide application. The conditions of life of water-dwelling
plants are so different from those of sub-aerial vegetation that
it would not be surprising if the respiration of the former was
carried on in a somewhat modified manner. Reducing sub-
stances occur in their tissues, and I have not yet found it
possible to detect masked oxidases in them by removal of
inhibitors by any of the methods previously described. It is
noteworthy that catalase was found in every case, being remark-
ably active in many.

The Oxidases in relation to Pigmentation. — It has been known
for a considerable time that there is a causal connection
between the occurrence of oxidases and sap-pigments in stems
and the veins of leaves. Reinke x investigated the chromogens
as far back as 1882. More recently they have been studied by
Wheldale, 3 Molisch, 3 Keeble, Armstrong and Jones, 4 Bartlett, 5
and others. The nature of the sap-soluble anthocyan pigments
cannot yet be regarded as firmly established. Wheldale regards
the anthocyanins as oxidation and condensation products of
colourless chromogens which are present in living cells as part
of a glucoside molecule. The hydrolysis of the glucoside is
considered to be a reversible enzyme action, and only the free
chromogen, which belongs to the aromatic group of chemical
compounds, can be attacked by the oxidase. This view, which
greatly stimulated research, has recently been shown to be in
need of some modification, or at any rate not to hold univer-

1 Reinke, Zeitschr. f.physiol. Chem. 1882, 6, 263.

' Wheldale, Progressus Rei Botaniccz, 1910, 3, 457 ; also Journ. of Genetics,
1911,1, 133.

3 Molisch, Bot. Zeitschr. 1905, 63, 145.

4 Keeble, Armstrong, and Jones, Proc. Roy. Soc. 1913, B, 87, 113.

4 Bartlett, H. H., Bull. No. 264, Bureau of Plant Industry, U.S. Dept. of Agric.

SOME RECENT WORK ON PLANT OXIDASES 121

sally. Bartlett, after a careful investigation into the nature
of a water-soluble ammonia-greening anthocyanin, concludes
that it is itself a glucoside, and states that the only non-
glucosidal ammonia-greening anthocyanin known to him is
insoluble in water. This, it may be remarked, is obtained from
Althaea. Molisch records the occurrence of anthocyanin in the
solid condition, both as amorphous and crystalline aggregates,
in many flowers and leaves. Keeble, Armstrong and Jones
have shown that the pale yellow sap-colour of the petals of the
wallflower is a mixture of hydroxy-flavone glucosides. From
this by suitable treatment a red pigment may be obtained, which
is not a glucoside. Oxidations of the hydrolysed products of the
yellow glucosides by means of oxidase, in presence of amino-
acids, result also in the production of pigments. An interesting
research by Willstatter and Everest 1 on the blue pigment of
cornflowers has just appeared. They have determined that the
blue pigment is the potassium salt of an acid (cyanin), which is
violet in the free state, whereas the red pigments are combina-
tions of this acid with simple organic acids. Thus the occurrence
of various shades of colour in the flower is explained. These
two authors also believe that all anthocyanins are present in
flowers as glucosides. Their paper contains many other points
of importance.

The beautiful changes of colour which many flowers undergo
in fading have arrested the attention of both the scientist and
the poet. This phenomenon has been employed in a beautiful
simile by " A. E." {Collected Poems, p. 9) :

Its edges foamed with amethyst and rose,

Withers once more the old blue flower of day :
There where the ether like a diamond glows
Its petals fade away.

By means of the use of benzidine and a-naphthol as micro-
chemical reagents, Keeble, Armstrong, and Jones have studied
the distribution of oxidases in flowers, and have shown that
when oxidase and chromogen are both present a white colour
may still persist owing to the action of an inhibitor. The
removal of the latter by dilute hydrogen cyanide permits of the
action of the enzyme on one of the artificial chromogens pre-

1 Willstatter, R., and Everest, A. E., Liebig's Annalen, 1913, 401, 189 ;' and
J.C.S. Dec. 1913, A. i. 1371.

I 2 '

SCIENCE PROGRESS

viously mentioned. Making use of plants of known pedigree
they established the occurrence of various kinds of white flowers,
such as the type described above in which an inhibitor exists,
and that in which an active oxidase is found, unaccompanied
by a chromogen. They have also explained the restoration of
colour to a flower decolorised in alcohol. For example, the
brown wallflower has yellow plastids and a red anthocyanin
sap pigment. Alcohol extracts the former, and reducing sub-
stances present in the cell destroy the latter. On addition of
water, however, the oxidases again become active, and produce
the red pigment from the chromogen by oxidation. So the
flower then appears red, and not brown, as the yellow is not
restored. The author has examined the flowers of about thirty
varieties of Iris by means of benzidine and a-naphthol, and on
the whole the results obtained follow closely those of Keeble,
Armstrong and Jones. The presence of a powerful inhibitor in
many of the flowers presents features of interest, and the restora-
tion of the anthocyanin pigment after decolorisation in alcohol
is only brought about in the more deeply pigmented forms.
The pigment is diffusible, and unless the chromogen is also
diffusible the supply ought not to diminish. That it does
diminish would appear to point to production of pigment from
a chromogen derived from a colloidal pro-chromogen by hydro-
lysis. In this connection it is noteworthy that in the red algae
there exists a plastid pigment which is seen to be bright red
when other pigments have been extracted from the plastids by
alcohol. It behaves like an indicator, being red with acids,
colourless with alkalis. Though the cell sap is faintly acid, it
is decolorised by boiling, apparently going into solution, but
addition of an acid restores the colour, probably by hydrolysis
of a chromogen. This the author hopes to examine further. 1

1 Since this paper was written, the above explanation of Keeble and Armstrong
as to the restoration of colour in petals has been severely criticised by Wheldale
and Bassett (Proc. Roy. Soc. 1914, B. 87, 300). These authors regard it as due to
ionisation changes, such as are undergone by phenolphthalein, rather than as an
oxidase action, though they are of the opinion that the enzyme is concerned with
the production of the anthocyan pigment in the first instance. The author has
satisfied himself as to the validity of the major part of this criticism by repeating
the work on Iris petals. It must, however, be pointed out that hydrogen peroxide
frequently behaves as a reducing agent ; this Wheldale and Bassett have over-
looked. The restoration of colour in the red algae is also brought about by acids,
as mentioned above.

SOME RECENT WORK ON PLANT OXIDASES 123

In many flowers there is an inhibitor in cells which contain
plastid pigments, and in all cells between them and the upper
surface. This was observed in Primulas by Keeble and Arm-
strong, and by the author in varieties of Spanish Iris. The
contrast of the dark colour of the benzidine oxidation products
in the petals with the colourless inhibition areas is frequently
very striking.

The white flowers previously mentioned as containing in-
hibitors have been shown to be Mendelian dominants, when
crossed with coloured varieties, whereas the whites which are
white through lack of chromogen behave as recessives.

The Role of the Oxidases in Plant Pathology

Since upon the death of the protoplasm oxidases act without
the restraints to which they are subject during its life, it might
well be supposed that conditions unfavourable to the normal
metabolism of the cell might result in increased oxidase activity.
This has been found true in a number of instances. It had been
observed that when mulberry trees were cut back too frequently
an abnormal yellow colour and crinkled appearance resulted in
the leaves. Suzuki 1 investigating this found that an excessive
production of oxidases had taken place in such yellow areas.
He attributed this to the lack of proper nutrition of rapidly
growing tissues. Much the same phenomena were observed by
Woods 2 in the "mosaic disease" of tobacco plants which have
been cut back. He also demonstrated that the condition was
rendered more acute by the application of certain manures
which increase the rate of growth.

More recently Bunzel 3 has investigated the oxidase content
of normal leaves of the sugar beet, and of those affected with
the "curly-top" disease, which has been shown by Ball 4 to
develop after the bite of an insect, the curly-top leaf-hopper
{Eutettix tenella). Bunzel ascertained that the leaves of the
curly-top plants had an oxidase content two to three times
as great as the healthy and normally developed ones. No
marked differences, however, could be detected between the
roots of the two kinds of plants. Bunzel admits that this

1 Suzuki, Bull. Agric. Coll. Tokyo, 1900, 4, 167 and 267.

* Woods, Bull. 18, Bur. Plant Industry, U.S. Dept. of Agric. 1902.

s Bunzel, Bull. 277, Bur. Plant Industry, U.S. Dept. of Agric. 1913.

4 Ball, Bull. 66, Bur. of Entomology, U.S. Dept. of Agric. 1911, pt. 4, p. 33.

i2 4 SCIENCE PROGRESS

observed increase may be due to a change in the juice by which
the pyrogallol oxidising enzyme becomes more active. The
extraordinary alterations in oxidase reactions brought about by
treatment with hydrogen cyanide and subsequent washing as
advocated by Keeble and Armstrong render it very probable
that such quantitative estimations are largely influenced by the
presence of inhibitors. The author's own work on Iris flowers
and other plant tissues has afforded additional evidence of the
widespread occurrence of these bodies. However, this does
not alter the fact that the functional activity of oxidase is greatly
increased in the affected leaves, producing, as it were, a state
of "fever," according to Bunzel. In this connection it may be
remarked that many apparent specific actions by oxidases, such
as the oxidation of benzidine by a tissue though it fails to oxidise
guaiacum, can be proved, by treatment with hydrogen cyanide,
to be due to inhibitors. Whether these act as genuine in-
hibitors, or by being themselves more readily oxidisable than
the added artificial chromogens, is as yet undecided. Bunzel's
direct measurement of oxygen absorption would appear to be
the most promising method of attacking this problem.

The Bearing of Oxidase Investigations on Technology

In addition to the interest of oxidase study for the silk and
sugar industries mentioned in the last section there are several
other more direct applications. The researches of Yoshida 1 in
1883 showed that an oxidase was concerned in the production
of the well-known black varnish obtained from the milk-like
sap of the lac tree, Rhus vermicifera and allied species. He
obtained from the sap an acid, urushic acid, which when oxidised
by the enzyme becomes black and forms the basis of the
varnish which is so much used in China and Japan. Eleven
years later Bertrand 2 confirmed and extended Yoshida's work,
giving the name laccase to the enzyme, and pointing out the
relationship of urushic acid to the hydroxy derivatives of the
benzene series.

In the preparation of tea also an oxidase has been proved
by Mann 3 to play an important part. In green tea the leaf is

1 Yoshida, Journ. C/iem. Soc. Trans. 1883, 43, 472.
s Bertrand, Compt. Rend. Acad. Sci. 1894, 118, 121 5.

s Mann, H. H. Quoted from Fowler's Biological and Enzytne Chemistry
(Arnold, London, 191 1).

SOME RECENT WORK ON PLANT OXIDASES 125

roasted immediately after picking, before any appreciable oxida-
tion takes place. In black tea, on the other hand, an oxidation
of the tannin is effected by an oxidase of the laccase class,
resulting in the production of a soluble brown substance to
which the colour of the infusion is due. The pungency, on the
contrary, is dependent on the amount of unoxidised tannin,
while the flavour is caused mainly by an essential oil. By
carefully regulating the different processes of withering, rolling,
and oxidation the qualities of the tea may be altered within
limits. All the operations involved must be carried out with
the utmost cleanliness to avoid bacterial contamination as far
as possible, as such gives rise to sourness, rendering the tea
unfit for consumption.

In the procuring of cocoa beans, too, fermentation processes
are involved which loosen the seeds in the fruit. In these
stages yeasts and acetic acid producing bacteria are active.
Oxidases are also at work both during the fermentation and
subsequent drying, as shown by Loew, 1 the change from the
violet colour of the fresh bean to a deep brown being due to
their agency.

The curing of tobacco again involves a fermentation. The
leaves after a preliminary withering are " sweated " in moderate
sized heaps, and fermented in very large heaps containing many
tons. It was at one time thought that this was a bacterial
process, but owing to the work of Loew 2 and other American
chemists it has been shown to be mainly one of respiration of
starch, sugars, and tannin, brought about by oxidases in con-
junction with hydrolytic enzymes.

Another instance of the importance of oxidases in commerce
is that of the blemish known as " sap stain " in lumber, by
which considerable portions of the wood of certain trees when
exposed to the air by sawing into planks or beams were dis-
coloured, and so depreciated in value considerably. It has been
demonstrated by Bailey 3 that this is brought about by an
oxidase.

The preparation of ensilage has been investigated by Russell 4

1 Loew, Ann. Report, Porto Rico Agric. Expt. Station, 1907, quoted from
Fowler loc. cit.

2 Loew, loc. cit. Quoted from Fowler, loc. cit.

3 Bailey, Bot. Gaz. 19 10, 60, 142.

4 Russell,/. Agric. Science, 1908, vol. ii. pt. 4.

i26 SCIENCE PROGRESS

within the last few years. He studied the changes taking place
in green maize stems packed closely together to form a "silo."
Bacterial action sets in, and also action of the respiratory
oxidases and other enzymes of the plant cells. So large an
amount of heat is generated by the oxidases that the tempera-
ture rises to such a degree as to inhibit further bacterial growth.
The hydrolytic and proteolytic enzymes still retain their activity,
however, and a complicated series of changes ensues, in which
organic acids appear among the products.

In the foregoing account of the oxidases the chief difficulty
experienced by the author has been that of deciding what to
omit, as the subject is of such dimensions and of such rapid
growth. Furthermore it has not been possible to present both
sides of all the questions involved, owing to limitation of
space and a desire to give a connected account of the various
researches.

PLANT CHIMERAS

By MACGREGOR SKENE, B.Sc.
Lecturer on Vegetable Physiology, Aberdeen University

The practice of horticulture and the study of heredity have led
to the production of innumerable hybrids, plants having their
origin in the fused sex-cells of two distinct races, species, or
even genera, and frequently betraying their dual nature by ex-
hibiting characteristics of both parents. From these legions of
intermediate forms, as to the sexual origin of which there is no
doubt, there stand apart a very few isolated cases of hybrids
which seem to have arisen in another fashion. By reason of
their supposed mode of origin they have long been labelled
graft-hybrids; and both because of this origin, which was
doubtful, and because of various peculiarities which they con-
stantly exhibited, a considerable amount of attention has been
paid them during the last eighty years or so. Only five years
ago, however, did the various problems involved prove capable
of an experimental solution. Professor Winkler, of Hamburg,
has succeeded in replacing the airy castles of theory by an
edifice built of solid fact enough, but of a nature more curious
than that of any of its predecessors.

The most notable of the so-called graft-hybrids is the shrub
known as Cytisus Adami, which is supposed to have arisen in
the following way. It is a common practice of gardeners to
graft the purple broom, Cytisus purpureas, on to the laburnum,
Cytisus Laburnum. Cytisus purpureus bears on its spiky stems
many tufts of fine purple flowers, but the stems are low-growing
and the plant makes no great show. Grafted on the laburnum,
however, it artificially raises its purple head and thereby greatly
enhances its decorative value. In the year 1829 the Parisian
gardener Adam observed that a bud from one of these grafts
had produced a novelty. The flowers on the new shoot were
indeed purple in colour, but instead of occurring in small erect
tufts they occurred in the fine drooping clusters so characteristic
of the laburnum. In other words, the inflorescence exhibited

127

128 SCIENCE PROGRESS

characters of both parents, the purple broom and the laburnum.
This was not confined to the flowers ; leaves and stem also
showed an intermediate structure. There could be no doubt
that this Cytisus Adami, as the new plant came to be styled, was
of hybrid origin ; and if the account of Adam were correct it
would seem that there could be equally little doubt that it had
arisen during, or subsequent to, the process of grafting. That
doubt has for various reasons been thrown on Adam's story is
no reflection on the individual, but merely results from the
general fact that practical men keep no exact records of the
plants passing through their hands, and in particular do not
carry out their operations under the carefully controlled con-
ditions which modern science demands.

Apart from actual proof there are strong reasons supporting
the "graft" origin of the hybrid. Perhaps the most important
is the fact that no attempt to raise seed from the laburnum
pollinated by the purple broom, or from the purple broom
pollinated by the laburnum, has ever succeeded : the two plants
are mutually absolutely sterile. And then we have the very
remarkable behaviour of the hybrid itself. Cytisus Adami is
now a common ornamental shrub ; it has been possible to
multiply the original shoot indefinitely by grafting, and its
appearance and characteristics are widely known and may be
studied in numerous private gardens. Its most striking feature
is that it does not maintain the intermediate character in all its
branches. From a shoot of typical Adami will arise, apparently
without reason, a branch of pure laburnum, or one which
possesses the characters of the purple broom alone. Not only
this, but even a single flower will show one half hybrid, and
the other belonging to one of the parents : a single petal may
have the same mixed constitution, or a single leaf. This
production of " vegetative throwbacks " is extremely rare in
sexual hybrids.

Striking as these facts are, so eminent an authority as Prof.
De Vries wrote in his "Species and Varieties" that there was
no evidence to show that Cytisus Adami had not arisen as a
sexual hybrid. Against the fact that the two parents are
mutually sterile he points out that although, since 1829 C. pur-
pureas has been grafted on C. Laburnum many thousands of
times, yet in no single case has this resulted in the formation of
a hybrid. That such had occurred on a single occasion is just as

PLANT CHIMERAS 129

probable, or as improbable, as that in one isolated instance an
ovule of laburnum had been fertilised by pollen from the purple
broom giving a seed of hybrid origin : that this latter is the true
explanation was Dr. Vries's belief.

We must encounter, too, the difficulty of explaining the
mechanism by which hybridisation during grafting could take
place. The stock never influences the specific characters of the
scion. The more luxurious growth of a delicate scion placed on
a sturdy stock is due solely to an improved food supply. Prof.
Winkler in an exhaustive memoir ("Pfropfbastarde," Part I.) has
shown that there is no well-authenticated case of a specific
change in stock or scion resulting from the influence of the
co-partner. There remained, seemingly, the supposition that
a fusion of cells of the two parents had given rise to an
organism bearing the characters of both. But without definite
proof it is not possible to believe that ordinary vegetative cells
of two highly organised seed-plants could assume the characters
of sex-cells.

One line of evidence, the nature of its progeny, might have
led to a solution ; but Cytisus Adami is sterile. In the long
course of its history it has produced two seeds, and both grew
up into typical laburnums. But the number is far too small to
make it permissible to draw conclusions from this fact.

Cytisus Adami is the best known and most widely distributed
" graft " hybrid. But one or two other similar cases are known.
Of these we may mention the hybrids between the hawthorn
and medlar to which the name Cratcegomespilus has been given.
Of these no less than three are known ; one is intermediate
between the two parents, of the two others one resembles more
closely the hawthorn, the second the medlar. Their origin is
shrouded in even greater mystery than that of the Cytisus
Adami; but it is equally certain that the parents are mutually
sterile, and that the hybrids produce vegetative throwbacks.

When Prof. Winkler commenced his investigations some
seven years ago our knowledge of the origin of these curious
plants was sadly indefinite. That they had arisen by grafting
seemed improbable ; that they possessed properties seen in no
other hybrids made a sexual origin equally doubtful.

Prof. Winkler saw that it was useless to attack the problem
by grafting laburnums or hawthorns ; that had been tried times
without number, with uniform lack of success. He looked

i 3 o SCIENCE PROGRESS

round for other plants which might proffer greater hopes of
positive results. In the first place, the subjects of experiment
must graft easily, and be readily reared in large numbers ; in
the second, they must have the property of producing large
numbers of adventitious buds from wounded surfaces. This was
of great importance, because he recognised that it was in new
buds arising from the graft, and not in the original scion, that
a modification was to be looked for. His studies in regenera-
tion enabled him to single out the most suitable plants, and
these he states are the poplars, the herbaceous members of the
Capparidacece, and the Solanums. His results were obtained
with these last.

Briefly, the method employed is as follows. Two to three
month old seedlings of Solanum lycopersicum, the tomato, are
decapitated, and the apex of the stump is split open about a
couple of inches. Into this slit is inserted the wedge-shaped
end of the tip of a seedling of Solanum nigrum, the nightshade.
The two are bound together with bast, and kept moist and
poorly lighted, till the wounded surfaces have grown well
together, and the graft is complete. If left in this condition
the nightshade thrives excellently, and produces flowers and
fruits on the tomato stump. But if the system be again de-
capitated at the point of union of the two plants, and if the
precaution be taken to remove all the buds from the axils of
the leaves of the tomato stump, then, after about a fortnight,
a large number of adventitious buds develop on the cut surface.
If the decapitation has been performed at the proper point there
will be on the cut surface a small wedge of nightshade tissue,
grown firmly between the two halves of the tomato stem.

Now all buds that developed on the tomato gave shoots of
pure tomato, and all buds that developed on the wedge of night-
shade gave pure nightshade. But in August 1907 Prof. Winkler
observed a bud which arose from a point on the line of junction
of the tissues of the two plants, and which developed into a
shoot of a unique character. The first leaf was a nightshade
leaf, and so were the fourth, fifth, and seventh leaves, and these
all arose from the side of the stem towards the wedge of night-
shade tissue ; but the second, third, and sixth leaves, which were
on the tomato side, were all tomato leaves ; and the eighth,
ninth, and eleventh, occupying positions opposite the line of
junction, were leaves of which one longitudinal half was tomato,

PLANT CHIMERAS 131

the other nightshade. In other words, the plant was a com-
posite one, the one longitudinal half being a nightshade, the
other a tomato.

The leaves of the tomato are large, feather-compound, hairy
of surface, thick in texture, light green in colour, and with
notched edges : those of the nightshade are smaller, simple,
almost glabrous, thin in texture, dark green, and entire. There
can arise no doubt as to the identity of the one or the other.

This plant Prof. Winkler aptly named a Chimcera in imitation
of Homer's " mingled monster of no mortal kind."

Following on this partial success, the ultimate aim of the
experiments was attained in succeeding years, when buds
developing similarly, at the line of junction of the two parent
tissues, produced shoots which were plainly of a hybrid nature.
Of these hybrids no less than five distinct types have been
described and named by Prof. Winkler, while other investigators
have obtained forms differing from any of these.

The first experimentally produced " graft hybrid " was
named Solatium tiibingense. It possesses leaves which are
simple, like those of the nightshade, but with the notched
margins, and the hairy surface of the tomato. Without entering
into details, it may be stated that the flowers, the fruits, and
the stem are also intermediate in character : the plant is easily
rooted and maintained by means of cuttings. Solatium Kcelreu-
terianum resembles the tomato, but has leaves with the glabrous
nightshade surface. Between these two extremes lie S. Gcertner-
ianum, S. Darwinianum, and S. proteus.

Of great interest is the fact that, like Cytisus Adami, these
plants produce vegetative throwbacks to one or other parent :
these are most abundant among shoots from adventitious buds
on cut surfaces ; but they also occur spontaneously. Happily
several of the hybrids are fertile, and the curious fact came out
that the seeds of any particular hybrid always give rise to plants
bearing the characters of one of the parents. Thus tiibingense
and Gcertnerianum always give nightshade; proteus always
gives tomato. Further, tiibingense and Gcertnerianum are
fertile with the nightshade, giving nightshade, but not with the
tomato ; while with proteus the reverse is the case. The
tomato and nightshade are mutually sterile.

The possibility of producing plants of a hybrid nature by
the process of grafting is therefore proved beyond all doubt.

i 3 2 SCIENCE PROGRESS

But we arc left with the difficulty of explaining the mechanism
by which this occurs. Prof. Winkler was at first inclined to
believe that his hybrids were Hyperchimceras, plants in which
the tissues of the two parents were mingled together in a very
intimate manner, instead of being isolated in two distinct
longitudinal strips. This view he gave up, after a discussion
in the German Botanical Society had brought out the difficulties
which stood in its way. He then expressed the opinion that
they had arisen by a cell-fusion at the point of grafting — a view
vigorously combated by Strassburger. To Prof. Erwin Baur
belongs the credit of having made the suggestion which subse-
quent investigation has proved to be the correct solution of the
problem.

He was engaged in the study of the heredity of the Pelar-
goniums, and he found, on examining anatomically the leaves of
those forms with white margins, that the organ consisted of a
core of green tissue surrounded by two or more layers of cells,
in which the chloroplasts were degenerate and contained no
chlorophyll — a hand of green tissue in a glove of colourless. At
the margin of the leaf the number of layers of cells is reduced till
finally only those with colourless chloroplasts persist, and thus is
produced the white margin. The idea of applying this arrange-
ment to explain the properties of the Solatium hybrids was
shortly afterwards made public. Thereupon Prof. Winkler
examined his plants to test the truth of the hypothesis. As it
happens, this is fairly easily done. Solanum lycopersicum possesses
24 chromosomes, S nigrum 72 : it was only necessary to count
the number of chromosomes in the different layers of the
vegetative points of the intermediate types.

Prof. Baur's theory proved to be correct. The hybrids are
indeed plants in which a core of one parent is enclosed in a
skin of the other. Tilbingense consists of nightshade covered
by a single layer of tomato ; proteus has two layers of tomato ;
in Kcelreuterianum and Gwrtnerianum the tomato is the core
covered by one and two layers of nightshade respectively. We
are dealing, then, with plants which are not hybrids in the exact
sense of the word at all; they are, in fact, chimceras just as much
as the original object to which that term was applied, with this
difference — that, as the tissues are laid one over the other, and
not side by side, the result is a plant which exhibits characters
intermediate between those of the parents : to express this

PLANT CHIMERAS 133

particular arrangement the term Peridural chimcera has been
adopted.

Let us see in what way this knowledge helps us to explain
the peculiarities of these plants. In the first place, the particular
form will resemble the one or other parent more closely, as the
one or other parent enters more largely into its composition :
a reference to the characters and structure of tubingense and
Kcclreuterianum shows this to be the case. Secondly, the
phenomenon of vegetative throwbacks is readily understood
when we see that a slight accidental injury or derangement of
the tissues of one partner will permit of the appearance of the
other in its pure state : this is, of course, more particularly the
case with adventitious buds, arising from a wounded surface.
And, finally, the fact that the intermediate form always breeds
true to one parent becomes self-evident when we remember
that the sex-cells are always produced from the sub-epidermal
layer, and therefore always belong to the one parent : that the
chimaera is sterile with the other parent is explained by the
same considerations. The parent to which the seeds of the
chimaera revert will be the parent which constitutes the sub-
epidermal layer, and this is in fact the case.

This explanation is admirably simple : can it be applied to
these original " graft hybrids," the origin of the whole discussion ?
Anatomical investigation has shown that it can. The arrange-
ment of the pigments in the petals of Cytisits Adami shows that
that shrub is a chimaera, which consists of a core of laburnum
with an epiderm of purple broom. The characters of the
epiderm and cortex of the fruit of Cratcegomespilus asniersii prove
it to be a hawthorn with the skin of a medlar. Minute investi-
gations of the anatomy of various other parts of the two plants
have only confirmed these results. And we recall the fact
that the two seeds which C. Adami bore both grew up into
laburnums.

The uniformity of these results is broken only by Solatium
Darzvinianum, the nature of which is not yet clear. Prof.
Winkler states that it is not a periclinal chimaera, and has
promised further investigations : pending the publication of
these, we cannot say how it is built up.

The theoretical interest of these results is of course very
great. A very awkward exception to various laws of heredity
has been removed. The opening paragraphs of a new chapter

i 3 4 SCIENCE PROGRESS

on regeneration have been written ; and an entirely unsuspected
power of accommodation in the most highly organised plants
has been discovered.

What the practical interest of the chimaera may be, it is hard
to say. The difficulty of its production, and the small number
of plants from which results may be expected, will probably
prevent its becoming more than a curiosity. We would hesitate
to suggest the possibility of a naturally blended tobacco, did we
not recognise that the suggestion is scarcely more fantastic than
the chimaera itself.

Apart from all this, it is some satisfaction to know that, after
all, Adam was right. He did obtain his hybrid from a graft — by
some accident, probably, a bud of purple broom became hollowed
out, and into the cavity grew laburnum tissues. And he was
to be excused if he did not recognise that his hybrid was
no hybrid, but that it was the materialisation of a very
ancient myth.

COLOURED THINKING AND ALLIED

CONDITIONS

By DAVID FRASER HARRIS, M.D., D.Sc, B.Sc. (Lond.), F.R.S.E.
Professor of Physiology and Histology in Dalhousie University, Halifax, N.S.

There are certain persons in whom sounds are invariably and
inevitably associated with colours. Whether these sounds are
those of the human voice or the notes of various musical instru-
ments, they are all heard as coloured. This kind of thing is
known as coloured hearing ; in French audition colore'e, in
German Jarbiges Horen.

The linking together of any two kinds of sensation is called
synesthesia ; of all the possible synsesthesise the linking of
colour and hearing is the commonest. A larger number of
persons than might be supposed are the subjects of coloured
hearing. As long ago as 1864 the chromatic associations of
one of these coloured hearers were described by Benjamin
Lumley (2). " I know a person," he wrote, " with whom music
and colours are so intimately associated that whenever this
person listens to a singer, a colour corresponding to his voice
becomes visible to his eyes; the greater the volume of the voice
the more distinct is the colour." This person heard Mario's
voice as violet, Sims Reeves' as gold-brown, Grisi's as primrose,
and so on.

But there is also a small number of persons who, whether
they hear in colours or not, always think in colours. These
persons, called coloured thinkers, do not have any sensation of
colour when voices or notes are heard, but they invariably
associate some kind of colour with such things as the names of
the days of the week, the hours of the day, the months of the
year, the vowels, the consonants, etc. This faculty is coloured
thinking, or chromatic conception, and has been called psycho-
chromaesthesia. A typical coloured thinker, who will tell you,
for instance, that Sunday is yellow, Wednesday brown, Friday
black, may not experience any sensation of colour on hearing
the organ played or a song sung. Certain persons are indeed

135

i 3 6 SCIENCE PROGRESS

coloured hearers as well as coloured thinkers ; but we should
distinguish the person who has linked sensations, a synaesthete
from the person whose thoughts are coloured, whose mentation
is chromatic, who is, in fact, a psychochromaesthete.

The literature of synesthesia is much more extensive than
any one would be inclined to think who had not made it a
special study. Nor is the condition described only in technical
publications ; there is an increasing tendency to recognise it in
current fiction. Thus in Dorian Grey we have : " her voice was
exquisite, but from the point of view of tone it was absolutely
false. It was wrong in colour." Musicians, it would appear,
are particularly liable to hear in colours : "The aria in A sharp
(Schubert) is of so sunny a warmth and of so delicate a green
that it seems to me when I hear it that I breathe the scent of
young fir-trees." The musical critic of the Birmingham Daily
Post thus once complained of a lady's singing : " Her voice
should have been luscious like purple grapes." Punch has, of
course, not failed to notice this tendency in musical criticism.
A writer in the Daily Telegraph had thus expressed himself :
" To a rather dark-coloured, deep, mezzo-soprano voice, the
singer joins a splendid temperament." Punch remarked : " We
ourselves prefer a plum-coloured voice with blue stripes, or else
something of a tartan timbre."

Monsieur Peillaube (53), editor of the Revue Philosophique, has
reported on four persons who have well-marked coloured
hearing for organ notes, and he calls attention to the numerous
cases amongst musicians of definite associations between notes
and musical instruments on the one hand, and colours on the
other, as well as between whole pieces of music and colours.
Thus Gounod, endeavouring to express the difference between
the French and Italian languages, and giving his preference for
the former, used terms relating to colours: "Elle est moins riche
de coloris, soit, mais elle est plus variee et plus fins de tintes."

Theoretically any two sensations may be linked, so that
coloured hearing is only one particular variety of synesthesia
(coupled sensations, secondary or dual sensations, Secondar-
empfindungen). No doubt the linking of colour with sound is
the commonest of these dual sensations, which, following
Bleuler (31), might be called sound-photisms. When a taste
produces light or colour we have a taste-photism ; similarly
there are odour-photisms, touch-photisms, temperature-photisms

COLOURED THINKING 137

and pain-photisms recorded in the annals of abnormal psy-
chology. A good example of a pain-photism occurs in a recent
novel, The Dream Ship (66). The whole passage is so appro-
priate to our subject that it may be quoted in full :

" Blair" (a boy) " decided all his likes and dislikes by colour
and smell. His favourite colours were yellow, red, green, and wet-
black. The last was very different to (sic) ordinary black, which
was the colour of toothache. Little rheumatic pains which he
sometimes got in his knees were grey. The worst pain you
could get was a purply-red one, which came when you were sad,
and gave you the stomach-ache. He had once solemnly stated
that the only colour he hated was yellowy-pink, but, as he
always called yellow pink, and pink yellow, no one had been
able to solve the riddle of this hated colour."

The black colours of toothache and the grey of rheumatism
were this boy's pain-photisms. Something of the reverse order
is indicated where a disagreeable colour is described as pro-
ducing a pain in the stomach. When Baudelaire said that musk
reminded him of scarlet and gold, he had an odour-photism.

When the reverse linking occurs we have an analogous
series. If light or colour produces a sound, it is a light- or
colour-phonism. This is what occurred in the case of the blind
man alluded to by Locke (1), to whom "scarlet was like the
sound of a trumpet " ; he had a colour-phonism, the colour
presumably being of the nature of a memory. When a taste is
coupled with a sound we have a taste-phonism, and there may
exist odour-, touch-, temperature-, and pain-phonisms respec-
tively. Sometimes the secondary sensation linked is of a more
vague character, as when screeching sounds produce disagreeable
general sensations very difficult to describe. They have been
called secondary sensations of general feeling, and they may be
akin to those unpleasant sensations evidently experienced by
dogs and other animals when they hear music. The late Mr.
Grant Allen was evidently alluding to this kind of thing when
he wrote, in an article on " Scales and Colours," that " Chaos
was in dark and gloomy colours, whereas light was treated in
white " in such a work as Haydn's " Creation."

Bleuler believes that phonisms of high pitch are produced by
bright lights, well-defined outlines, small and pointed forms,
whereas phonisms of low pitch are produced by the opposite
conditions. An interesting thing may be mentioned in con-

i 3 8 SCIENCE PROGRESS

nection with the difference in colour aroused by spoken words
and by whispering. Dr. Helene Stelzner (51) tells us that in
her own case full-toned speech appears as a coloured picture,
whereas whispering, with its much less resonant vowels, appears
like a copper-plate engraving, that is as non-chromatic.

Quite apart from all these things— synaesthesiae — is coloured
thinking or chromatic mentation. Here it is not a question of a
sensation being present at all, it is that certain persons who
have this power, faculty, or disability cannot visualise any
concept without seeing it in the mind's eye as coloured in
some way or other. Indeed the majority of the coloured
thinkers questioned by the author do not experience colours
when they hear sounds or musical tones, but they cannot think
of anything definitely, the month, the day, the hour, without its
being thought of as red or yellow or black or white or brown or
green or blue. There is no approach towards unanimity in the
colours thought of in association with any one concept or word ;
for instance, for Saturday the colours selected at random from
records in my possession are white, yellow, steel-grey, white-
grey, crimson, brown. The coloured thought may be called a
psychochrome, and persons who think in colours psycho-
chromaesthetes, the faculty or disposition to think in colours
being psychochromaesthesia.

Apparently the concepts to be most commonly coloured are
those for the vowels, the consonants, the months, the days, and
the hours of the day. Thus the vowel "a" as in "fame" is
mentally coloured in the following five ways in five different
persons— red, black, green, white-grey, and white respectively.
Or take the vowel " u " as in " usual " ; we find it psychically
coloured as grey-white, yellow, black, brown, blue, and green
in six different coloured thinkers. Similarly, whole words are
associated with colours in the minds of this class of thinkers.
One person says he divides all words into two great classes, the
dark and the light. Random examples of dark words are— man,
hill, night, horse, Rome, London ; and of light— sea, child,
silver, year, day, and Cairo. Or again, another coloured thinker
divides up the numerals into those associated with cold colours,
grey, black, blue, green, and those with warm, red, yellow,
orange, brown, purple, and pink. The odd numbers have the
cold colours, the even the warm. In some cases, as might be
expected, the coloured concepts are appropriate or natural,

COLOURED THINKING 139

as when the word scarlet is scarlet, black black, and white
white. But an examination of psychochromes shows us that
this reasonableness does not necessarily always occur. Thus
the word " apple" is to one coloured thinker a slate-grey, which
is not the colour of any real apple, and the word " cucumber " to
the same person is white ; now only the inside of the vegetable
itself is white.

Some kind of method, however, may be traced in this
chromatic madness, for, according to Bleuler(3i), high-pitched
notes produce the lighter tints of colour, but low-pitched the
darker shades. According to this authority the colours oftenest
aroused in the synaesthesia, sound-photism, are dark brown,
dark red, yellow, and white, which is not at all the statement of
the frequency of occurrence in coloured thinking. From the
records of the psychochromes of two brothers, the relative order
of frequency of the colours is white or grey, brown, black,
yellow, red, green and blue ; violet and indigo not occurring.
Dr. Helene Stelzner (51) says that green is the colour least
commonly thought of. But individual differences are extreme :
thus both purple and violet are such favourites with some
coloured thinkers that they hardly ever think in terms of any
other colours. The present writer (55) has examined the psycho-
chromes of two men, one woman, and one child, with the result
that the relative order of frequency of occurrence comes out as
white, brown, black, yellow, green, blue, red, pink, cream,
orange, and purple. It is thus clear that the colours thought of
are not exclusively the pure or spectral ones, for certain non-
spectral colours like brown, pink, cream, white, and black are
quite commonly reported. The novelist Ellen Thorneycroft
Fowler, in a private communication to the author, wrote : " The
colour which I always associate with myself, for no earthly
reason that I can discover, is blue. Therefore ' E.,' my initial
letter, is blue, April the month of my birthday is blue, and 9 the
date of my birthday is blue." This is known as " colour
individuation," and has been made a special study of by Paul
Sokolov (47) in his paper " L'individuation coloree," read before
the Fourth International Congress of Psychology held at Paris
in 1900. Some people, in short, have their favourite colours,
and with these they invest their pleasant thoughts, while their
unpleasant thoughts they find coloured by the tints they are not
fond of.

, 4 o SCIENCE PROGRESS

Apart, however, from whether certain colours are favourites
or not, some few persons have the consciousness of a colour
more or less present with them. Thus R. L. Stevenson had,
so he tells us, a feeling of brown which, during his attacks
of fever, was unusually distinct. It was "a peculiar shade of
brown, something like sealskin."

As might be expected, so acute an observer as Mr. Rudyard
Kipling has not failed to notice coloured thinking. In his very
curious story "They "(52) he describes the colour concepts ex-
perienced by a blind old lady, who opens an interview by com-
plaining that certain colours — purple and black — hurt her. Her
visitor asks, " And what are the colours at the top of whatever
you see " ? "I see them so," she replies, " white, green, yellow,
red, purple ; and when people are very bad, black across the
red, as you were just now." The old lady goes on to say that
ever since she was quite a child some colours hurt her, and
some made her happy. " I only found out afterwards that
other people did not see the colours." So unfamiliar is coloured
thinking to the ordinary person that a critic wrote {The Academy
and Literature, October 8, 1904), " Such tales as ' They' are sheer
conundrums." Another writer asked more pertinently, " Are
the colours the blind woman described the colours of different
thoughts?"

In Mrs. Felkin's novel In Subjection (43) (1900) the heroine,
Isabel Seton, is evidently a coloured thinker. Some of her
colour associations are given on page 149. The novelist, in a
letter to the writer, was good enough to explain that these
experiences of her heroine are based on those of an actual
prototype, some of whose additional psychochromes she
kindly mentioned. Isabel Seton has synaesthesia also, for the
actual sounds of voices call up colours. Thus, soprano voices
are to her pale blue or green or yellow or white, contraltos are
pink or red or violet, tenors are different shades of brown,
while basses are black or dark green or navy blue.

In the novel Christopher, by Richard Pryce(6i), there is an
interesting allusion to a boy who is described as not morbid,
although he is evidently a synaesthete and a coloured thinker.
He talks of playing the sunset on the piano (a colour-phonism),
and of smelling moonlight (a light-olfaction). In a novel,
Youth's Encounter (64), published only last year (1913), we are
told that to one of the characters " Monday was dull red,

COLOURED THINKING 141

Tuesday was cream coloured, Thursday was dingy purple,
Friday was a harsh scarlet, but Wednesday was vivid apple-
green, or was it a clear, cool blue ? "

It is difficult to express the character of these coloured
concepts to persons — and they are the majority of people — who
never experience this sort of thing at any time. The colours
are not present so vividly as to constitute hallucination.
Coloured visualisings never become hallucinatory, possibly
because they are of the nature of thoughts, rather than of
subjective sensations. Chromatic conception belongs to the
physiology, not to the pathology of mind. Coloured thinkers
are not continually plagued with phantasmagoria. Mental
colourings do not obtrude themselves into our mental life ;
they are habitual, natural, chromatic tincturings of one's con-
cepts, and have been so long present to one's consciousness
that they have long ago become part of our mental belongings.
They are invariable and definite without being disturbing.

One coloured thinker has thus expressed himself: "When
I think at all definitely about the month of January the name
or word appears to me reddish, whereas April is white, May
yellow, the vowel ' i ' is always black, the letter ' o ' white, and
1 w ' indigo-blue. Only by a determined effort can I think of ' b '
as green or blue, for me it always has been and must be black ;
to imagine August as anything but white seems to me an
impossibility, an altering of the inherent nature of things."
There is, thus, an inherent definiteness, finality, and constancy
about each thinker's psychochromes that is very striking. But
it is not alone letters and words that are habitually thought
of as coloured, certain coloured thinkers always associate a
particular colour with their thoughts about a particular person.

The author of The Corner of Harley Street remarks (p. 251):
" If only we could use colours now to express our deeper
attitude on these occasions, as some of your fellow clergy wear
stoles at certain seasons, with what pleasant impunity could we
write to one another in yellow or purple or red, leaving black
for the editor of the Times, or the plumber whose bill we are
disputing."

"Our alphabet is not rich enough for the notation of the
cockney dialect," writes Mr. Richard Whiteing in No. 5, John
Street. " I can but indicate his speech system by a stray word
which, if there is anything in the theory of the correspondence

i 4 2 SCIENCE PROGRESS

between sounds and colours, should have the effect of a stain
of London mud." This is evidently an allusion to coloured
thinking; there is unfortunately no theory at all as yet, but
there is the fact of chromatic conception. Quite recently (191 3)
there was in the British Review (65) a vivacious article dealing
with coloured thinking from the popular standpoint. The
literature that contains the most systematic discussion of
coloured thinking is that of the decadent poets of France, the
symbolards, as they are called. Some account of their psycho-
chromes is given in Lombroso's Man of Genius (30). The
eccentric poet Paul Verlaine belonged to this school. It evi-
dently includes synaesthetes as well as coloured thinkers for,
for them, the organ is black, the harp white, the violin blue,
the trumpet red, and the flute yellow. Further they think of the
vowel " a " as black, " e " as white, " i " blue, " o " red, and " u "
yellow. One of them, Stephane Mallarme, has explained in his
pamphlet Traite du verbe how these things have come to be.

The following verses — for I hesitate to call them poetry —
seem to be an attempt to express the associations of emotions
symbolised by the mental colourings of the vowels.

VOYELLES

A noir, E blanc, I rouge, U vert, O bleu, voyelles,
Je dirai quelque jour vos naissances latentes ;
A noir corset velu des mouches eclatantes
Qui bombillent autour des puanteurs cruelles.

Golfes d'ombre E, candeur des vapeurs et des tentes,
Lances des guerriers fiers, rois blancs, frissons d'ombelles,
I pourpres, sang crache, rire des levres belles
Dans la colere les ivresses penitentes.

U cycles vibrement divins des mers virides,
Paix des patis semes d'animaux, paix des rides
Que l'alchemie imprime aux grands fronts studieux.

O, supreme clairon plein de strideurs etranges,
Silence traversee des Mondes et des Anges,
O l'omega, rayon violet des ses yeux.

J. A. Rimbaud.

We are now, perhaps, in a position to make some inquiry
into the characteristic features of coloured thinking. The first
point that strikes one is the very early age at which these
associations are fixed. This was a feature recognised by
Galton in his classic examination of the subject in 1883 (10).

COLOURED THINKING 143

The present author's observations fully confirm this point ; he
has in his possession many letters from coloured thinkers in
which the details of their psychochromes differ in the widest
possible manner, but all agree in that they testify to the very
early age at which the associations were formed. After the
publication of the writer's article in the Scotsman, December 29,
1908 (59), he received a number of letters spontaneously sent, all
emphasising this feature in such phrases as, "ever since I can
remember," " ever since childhood I have always had it," " I do
not remember the time when I had not," etc. A writer in
Nature in 1891 (29) reports on the psychochromes of his
daughter when seven years old, at which age she had specific-
ally different colours for the days of the week, namely, blue,
pink, brown or grey, brown or grey, white, white, and black.
The months of the year were coloured in the following way by
a girl often who had so thought of them ever since she could
remember— brown, olive-green, " art blue," green-yellow, pink,
pale green, pale mauve, orange, orange-brown, grey, grey out-
lined in black, and finally red.

A boy ten years old is reported in the article on Colour
Hearing in the British Review (65) to have " noticed that the
number 8 invariably provoked in him the sensation of apricot
yellow, and the number 15 that of peacock blue." There
seems not the slightest doubt that these colour associations
are amongst the earliest that are formed in the child mind of
the coloured thinker.

The second characteristic of coloured thinking is the un-
changeableness of the colour thought of. Middle-aged people
will tell you that there has been no alteration in the colours or
even in the tints and shades of colour which for many years
they have associated with their various concepts. Galton
remarked on this in his original monograph ; " they are very
little altered," he said, " by the accidents of education." Galton's
phrase was, " they result from Nature not nurture." Just as
their origination is not due to the influence of the environment,
so the environment exercises no modifying influence on them
during a long life.

The third characteristic of psychochromes is their extreme
definiteness in the minds of their possessors. Contrary to what
might reasonably be expected, the precise colours attached to
concepts are by no means vague or incapable of accurate verbal

i 44 SCIENCE PROGRESS

description. A coloured thinker is most fastidious in the choice
of terms to give adequate expression to his chromatic imagery.
One of these is not content, for instance, with speaking of
September as grey, he must call it steel-grey ; another speaks
of a dull white, of a silvery white, of the colour of white
watered silk, and so on. One child speaks of March as " art
blue," whatever that is, another of 6 p.m. as pinkish. The
degree of chromatic precision which can be given by coloured
thinkers to their visualising is as extraordinary as any of the
other extraordinary things connected with this curious subject.

The fourth characteristic is the complete non-agreement
between the various colours attached to the same concept in
the minds of coloured thinkers. Thus, nine different persons
think of Tuesday in terms of the following colours — brown,
purple, dark purple, brown, blue, white, black, pink, and blue.
Again, September is thought of as pale yellow, steel-grey,
and orange by three different coloured thinkers respectively.
Once more, the vowel " i " is thought of as black, red-violet,
yellow, white, and red respectively by five persons gifted with
chromatic mentation. Unanimity seems hopeless, agreement
quite impossible; the colours are essentially individualistic.

The fifth characteristic of psychochromes is their unaccount-
ableness. No coloured thinker seems to be able to say how he
came by his associations; "I cannot account for them in any
way " is the invariable remark one finds in letters from persons
describing their coloured thoughts.

The sixth characteristic is the hereditary or at least inborn
nature of the condition. Galton's phrase was " very hereditary."
The extremely early age at which coloured thinking reveals
itself would of itself indicate that the tendency was either
hereditary or congenital. The details of a case of heredity from
father to son have been reported for coloured hearing by Lauret
and Duchassoy (22, 44, and 50) ; a case of coloured thinking
reported by the present writer was one of heredity also from
father to son (55). But these related coloured hearers did not
see the same colours for the same sound, nor did the two
coloured thinkers think in the same colours. From the writer's
inquiries, coloured thinking is certainly congenital even when
it cannot be proved to be hereditary. This point will come
up again in connection with the origin of the condition, T^ut
we may at present note that those who have studied the

COLOURED THINKING 145

subject are unanimous in denying that, at any rate, coloured
thinking is due to environmental influences.

It may now be asked what manner of people are they who
are coloured hearers or coloured thinkers or both. The late
Mr. Galton told us that they are rather above than below the
average intelligence. The writer's observations would in the
main confirm this ; they are at least invariably well educated
persons who confess to being coloured thinkers. In his book
Mr. Galton gave a few names of distinguished persons of his
acquaintance, and his list might be brought up to date by the
addition of some names quite as distinguished. But all persons
who have coloured hearing or coloured thinking are not neces-
sarily distinguished — a large number, as we have seen, are yet
children — but they are all probably more or less sensitive.
Possibly they are more given to introspection than is the
ordinary person. At any rate, what is quite certain is that both
synaesthetes and psychochromaesthetes belong to the group of
strong visuals or "seers" as Galton called them. Seers are
persons who visualise or exteriorise their concepts either as
uncoloured forms or as coloured in some way or other. The
uncoloured thought-forms are very curious, some of which
Galton gave as examples in the appendix to his work. One
distinguished neurologist always sees the numerals 1 to 100
in the form of a ladder sloping upwards from left to right
into the sky. As this concept is not coloured it cannot be called
a psychochrome, but it might be called a psychogram. A
psychogram is, then, the uncoloured thought-form of a concept,
and people who have psychograms must be strong visualisers.

The school of symbolist poets in France to which Ghil,
Malarme, Rimbaud, and Verlaine belong, appears to lay a great
deal of stress on the so-called meaning of colours. The school
evident^ includes both coloured hearers and coloured thinkers ;
but whereas the majority of coloured thinkers derive no par-
ticular meaning from their psychochromes, the symbolists
attach considerable significance to the colours which happen
to be associated with their thoughts. The different vowels, for
instance, mean to them or represent for them particular
emotions or states of mind not in virtue of the sound of the
vowel but entirely through the related colour. The particular
emotion symbolised by any given colour seems to the ordinary
person rather arbitrary if we judge by the details in Rimbaud's
10

i 4 6 SCIENCE PROGRESS

poem ; but we are all aware that there has always been a ten-
dency to represent emotional states in terms of the language of
colour. Homer spoke of " black pains"; we constantly speak
of a black outlook, a black lie, a white lie, a black record, a
grey life, a colourless life, and so on. There is, in fact, growing
up in England a school of musicians who hold that it should be
possible and pleasurable to represent music chromatically.
Whether the general public will ever enjoy silent music seems
very doubtful, but it is notorious that most people derive a great
deal of pleasure from the display of coloured lights, illuminated
vapours, coloured steam, "fairy fountains," Bengal lights, a
house on fire, and other exhibitions in the open air. People
undoubtedly do like to see great surfaces or masses vividly
coloured as in the rainbow, the sunrise or sunset, the afterglow
on snowy mountains, the streamers of the northern lights, etc.
But whether they would care to have audible music sup-
pressed and to have offered them a succession of coloured
surfaces or patches of colour even following one another in
the sequence or rhythm required by music, is open to serious
question. Such, however, is the intention of Mr. A. W.
Rimington, as explained in his book Colour in Music (63), in
which there is much that is true and interesting. " It is un-
deniable," he writes, " that as a nation our colour sense is
practically dormant. . . . Compare our colour sense with that
possessed by the Japanese, the Indians, or even the Bulgarians
and Spaniards. . . . To my mind a widespread, refined colour
sense is more important than a musical one." Long before
Mr. Rimington's work was published, there appeared a little
book, privately printed at Leith in Scotland, called Chromography
or Tone-colour Music (23). The author assigned a colour to
each of the notes of the scale thus — Do = red ; re = orange ;
mi = yellow ; fa = green ; sol = blue ; la = violet-purple ; ti =
red-purple.

Many persons have synesthesia in connection with musical
tones (sound-photisms) ; two reported on by Albertoni (24)
associated blue with the sound of Do (C), yellow with mi (E),
and red with sol (G). But it was discovered that they were
colour-blind for red (Daltonism). Now, whereas they could
recognise and name the other notes, they could not name G, a
disability which Albertoni thinks was related to the Daltonism ;
he has accordingly called it auditory Daltonism (Daltonismus

COLOURED THINKING 147

auditivus), a psychical deafness depending on the red-blindness,
since the note to which they were psychically deaf was the one
which called up mentally the particular colour, red, to which
they were actually blind.

It might now be asked whether we have any explanation
of the causes or causal conditions of coloured thinking, why
may thoughts be coloured at all, and why should particular
thoughts come to be associated with particular colours? Why
should only a few persons be found to be coloured thinkers ?
The answers, if answers they can be called, are extremely dis-
appointing, for we have no satisfactory explanations of any of
these matters. The very arbitrariness of the associations defies
theoretical analysis.

If it is the function of science merely to describe, then our
work is done ; but in a subject such as this, to make no attempt
to account for the abstruse phenomena observed would be a
distinctly feeble conclusion of our studies. It has been sug-
gested that the cause of coloured thinking is no more recondite
than the influence of some picture-book which in early life
determined for us ever afterwards the colours of certain con-
cepts. Now though many people do regard their coloured
thinking as a childish survival, the picture-books will account
for very few of the best established psychochromes. In some
few cases, environmental influences do seem to have been
causal. Thus, in one case known to the writer, the colour of
February as white was accounted for by the influence of the
surroundings. The earliest February remembered was snowy,
and, through the whiteness of snow, the concept of February
came to be and ever afterwards remained white. But it is clear
that if environmental influences are operative in anything like
a large number of cases, the colours for such concepts as the
months of the year ought to be far more uniform than they are.
No common origin of external source can make one person
think of August as white, another as brown, and yet another
as crimson. If August is white to one person because it is
the month of white harvest, then it ought to be white to all
persons capable of receiving any impressions as to the colours
of harvest. But to the vast majority of people it is perfectly
absurd to talk of August having any colour at all ; and, to the
few who think it coloured, it has not by any means the same
colour ; all seems confusion.

i 4 8 SCIENCE PROGRESS

Monsieur Peillaube (54) has made a suggestion of a different
kind as likely to explain some of these colour associations.

Monsieur Peillaube became acquainted with a Monsieur Ch ,

who had audition colorde as well as coloured thinking. Monsieur

Ch had an excellent memory, and was able to submit his

conceptions to searching introspection, with the result that
he seems to have discovered what may be called the missing
link in the associational chain of mental chromatic events. To
this coloured thinker, the lower notes of the organ were of a
violet colour. This seems to have been brought about in the
following way : low notes of any kind were sweet and deep
{donees et profondes), the colour violet is sweet and deep,
therefore it came to pass that the low notes were associated

with violet. Similarly to Monsieur Ch , the vowel sound

of " i " was suggestive of something vive et gaie, the colour
green had always been associated with liveliness and gaiety,
therefore he thought the vowel " i " was green. These con-
clusions were reached only after considerable introspection, for
it must be understood that the link between the low notes and
the colour violet was by no means an explicit or definite presen-
tation in this person's mind at the time that Monsieur Peillaube
suggested the inquiry. Peillaube's theory, then, is that these
apparently arbitrary and instantaneous linkings of sounds (x) to
colours (y), or of thoughts to colours, are really after all cases
of association of two terms through the intermediation of a
third factor an emotional link (1) now subconscious but re-
vivable. The sequence was x — 1 — y, but in course of time the
" 1 " had dropped out of consciousness, leaving the " x " and the
"y" apparently indissolubly joined together.

Finally, it may be asked, would the capability of coloured
thinking cause its possessor to be classed as mentally abnormal ?
The answer is in the negative. Coloured thinkers may not
conform to the usual or most commonly met with mental type,
but they deviate from that type only in the same way that
geniuses deviate from it. Inasmuch as they deviate from the
normal, coloured thinkers are of course abnormal, but there is
nothing in them that is allied to instability of mental balance.
Some coloured thinkers may no doubt belong to families in
which some degree of mental instability is present ; or, on the
other hand, some relatives of coloured thinkers may possess a
high degree of artistic or musical ability, of scientific or philo-

COLOURED THINKING 149

sophical insight, that quality, of genius in fact, so exceedingly-
difficult to define. Genius is something notoriously not con-
ferred by training or education ; if not inborn it cannot be
acquired; exactly the same may be said of coloured thinking.
Our studies have at least shown us this, that it is not in the
ordinary type of mental constitution, but in the recesses of
the slightly supernormal that this recondite problem of psycho-
logy presents itself for analysis and explanation.

Appendix
Being the Psychochromes in an Actual Case

"a. Blue-white (like a dead tadpole).

b. Dark brown-red.

c. Brighter red.

d. Pea-green.

e. Fawn-yellow.

/ A yellow, brighter than c.

g. Dark brown, nearly black.

h. Black.

i. Chocolate brown.

/. A dull red (not the same shade as the other reds)

k. Bright brick-red.

/. Black.

in. Bright yellow.

7i. Dark brown (nearly black).

0. White.

p. White with just a tinge of blue.

q. Pale blue-green.

r. Black (nearer to h than to i).

s. White.

/. Mustard colour (ugly).

u. Brown-yellow.

v. Olive-green.

w. Red (like c).

x. Green.

y. An ugly yellow.

z. Very bright scarlet.

Sunday. Red.

Monday. Pea-green.

Tuesday. Fawn-yellow.

Wednesday . Black.

Thursday. Fawn (not as bright as Tuesday).

Friday. Green (a very ugly bile colour).

Saturday. White.

i5o SCIENCE PROGRESS

January. Dull red.

February. Fawn.

March. A green mustard colour.

April. Blue-white.

May. Sunshine colour.

June. Dull red.

July. A slightly darker red.

August. Olive-green (more yellow than n).

September. White.

October. Green.

November. Black-brown.

December. A blue shot with green.

Christmas. White.

Whitsun. Nearly a rose-pink.

Easter. Mauve with something white in the middle.

One. Black.

Two. Blue-white.

Three. Fawn.

Four. Dark red.

Five. White.

Six. Bright yellow.

Seven. Black.

Eight. White.

Nine. Green.

Ten. Mustard green.

Eleven. Brown-yellow-green.

Twelve. Pale brown."

Bibliography

i. 1690. LOCKE, John, Philosophical Works. London, 1872, vol. ii. p. 26.

2. 1864. Lumley, B., Reminiscences of the Opera. London, 1864, pp. 98, 99.

3. 1873. Bruhl, Wien. med. wochens. Nos. 1-3.

4. 1879. Lewes, G. H., Problems of Life and Mind. Third Series, London, 1879.

5. 1880. Galton, F., Nature. London, 1880, vol. xxi. p. 252.

6. 1880. ibid. p. 494.

7. 1881. Bleuler, E., und Lehmann, K., Zwangmassige Lichtempfindungen

durch Schall und verwandte Erscheinungen. Leipzig, 1881.

8. 1881. Steinbrugge, Ueber secondare Sinnesempfindungen. Wiesbaden, 188 1.

9. 1882. MAYERHAUSEN, Uber Association der Klange speciell der Worte mit

Farben, Klin. Monatsbl. J. Augenheilk, 1882.

10. 1883. Galton, F., Inquiries into Human Faculty and its Development.

Macmillan, London, 1883, pp. 145-77.

11. 1883. Lussana, Sur l'audition coloree, Arch. Hal. de Biol. 88.

12. 1883. Pedrono, De l'audition coloree, Annal d'Oculisle, 1883.

13. 1883. Schenkl, Ueber Association der Worte mit Farben, Prager Medic.

Wochenschr. 1883.

14. 1884. Hilbert, Klin. Monatsbl. '. Augenheilk.

COLOURED THINKING 151

15. 1885. DE Rochas, A., Audition coloree, La Nature, April, May, September,

1885.
[885. GlRANDEAU, De 1'audition coloree, L'Encephale, No. 5, 1885, P- 589.
[887. BARATOUX, Audition coloree, Progres MJdicale, 1887.
[887. FERE, C, La vision coloree et l'equivalence des excitations sensorielles.

Soc. de Biol. Paris, 1887.
[887. Pick, Mendel's Neurolg. Centralbl, 1887, p. 536.
[887. Urbantschitsch, Sitzungsbericht. d. Gesellsch. d. Aertze in Wien,

October 1, 1887.

[887. Munch, med. Woch. October 25, 1887, p. 845.

[888. LAURET et DUCHASSOY, Bull. Soc. de psychol. physiol. Paris, tome iii.

p. n ; Abstract in Centralbl. fur Physiol. Leipzig und Wien, 1888

s. 125.
[888. Watt, William, Chromography or Tone-colour Music. Leith, 1888.
[889. Albertoni, Abstract in Centralbl. f. Physiol. Leipzig und Wien, 1889,

s- 345-
[889. Kaiser, Association der Worte mit Farben, Arch.f. Augenheilk, 1889.
[889. Raymond, P., Une observation d'audition coloree, Gazette des Hopitaux,

1889.
[890. De Mendoza, Suarez, L'audition coloree. Paris, 1890.
[891. Delstauch, Une observation d'audition coloree, Annal.des maladies de

Voreille, 1891.
[891. Holden, Nature. London, 1891, vol. xliv. p. 223.
[891. Lombroso, C, The Man of Genius. London, W. Scott, 1891, p. 231.
[892. Bleuler, Article, Secondary Sensations (Pseudochromxesthesia), Diet.

psych, med. Edited by Tuke, London, Churchill, 1892.
[892. Calkins, Mary W., Amer.Journ. Psych, vol. v. No. 2, November 1892.
[892. Gruber, L'audition coloree, Proc. Intern. Cong. Exper. Psych. London ,

1892.
[892. Krohn, Pseudochromassthesia, Amer. Journ. Psych. October 1892.
[893. Calkins, Mary W., Statistical Study of Pseudochromassthesia and of

Mental Forms, Amer. Journ. Psych. July 1893.
1895. Mirto, G., Contributo al Fenomeno di Sinestesia visuale. Palmero,

1895.
[895. Robertson, W. J., A Century of French Verse. London, 1895. (For

translation of Arthur Rimbaud's poem " Les Voyelles.")
[897. ZEHENDER, Ein Fall von Geschmaksphotismus, Klin. Monatsbl. /.

Augenheilk, 1897.
[899. Symons, A., The Symbolist Movement in Literature, 1899.
[899. Claviere, J., L'audition coloree, Ann. Psychol, vol. v. 1899, pp. 161-78

[899. Ann. de Soc. Psych, vol. ix. pp. 257-71, 1899.

[900. Daubresse, Audition coloree, Rev. Philosoph. 1900.

[900. Fowler, E. T., In Subjection. London, Hutchinson, 1900, p. 149.

1 901. Laignel & Lavastine, Audition coloree familiale, Rev. Neurolog.

1901.
1901. Lemaitre, Audition coloree et phenomenes connexes observes chez

des ecoliers. Geneve, 1901.
[901. Sokolov, P., Individuation coloree, Rev. Philosoph. 1901.
[901. L'individuation coloree, Trans. IV. Cong, intern, de psychol. tenu

a Paris, 1900. Paris, 1901, pp. 189-93.
48. 1902. Romby, L'Hysterie de Ste. Therese, Arch, de Neurol, vol. xiv. 1902.

I5 2 SCIENCE PROGRESS

49- I9°3- DRESSLER, L'audition coloree, evolue-t-elle ? LAnnee Biol. vol. viii.
I9°3. P- 4o6.

50. 1903. Lemaitre, Cas d'auclition coloree hallucinatoire cas heVeditaire,

LAnne'e Biol. vol. viii. 1903, p. 421.

51. 1903. Stelzner, Helene, F. Fall von akustisch-optischer Synaesthesie,

Graefe's Arch. Ophth. Leipzig, vol. Iv. 1903, pp. 549-°3-

52. 1904. Kipling, R., Traffics and Discoveries. London, 1904.

53. 1904. Peillaube, Rev. Phil. Paris, November 1904, p. 675.

54. 1904. Communication to the VI. International Congress of Physiology.

Brussels, September, 1904.

55. 1905. Harris, D. Fraser, Psychochromaesthesia and certain synesthesias.

Edin. Med. Journ. December, 1905.

56. 1905. Lomer, G., Farbiges Hdren (Auditio Colorata), Arch. f. Psychiat.

Berlin, 1905, vol. xl. pp. 593-601.

57. 1905. Colville, W. J., The Human Aura and the Significance of Colour.

London, 1905.

58. 1908. Harris, D. Fraser, Coloured Thinking, Journ. Abn. Psychol. Boston,

June-July, 1908, p. 97.

59. 1908. Coloured Thinking. Scotsman, December 29, 1908.

60. 1908. Coloured Thinking. Rev. Neurol, and Psych. Edin. September,

1908.

61. 191 1. Pryce, R., Christopher. London, Hutchinson & Co., 191 1, p. 81.

62. 191 1. Bashford, H. H., The Corner of Harley Street. London, Constable,

1911, p. 251.

63. 1912. RlMiNGTON, A. W., Colour in Music. London, 1912.

64. 1913. Mackenzie, C, Youth's Encounter. Toronto, Bell & Cockburn, 1913.

65. 1913. Martindale, C. C, Colour Hearing, British Review, April 1913.

66. 1913. Stockley, C, The Dream Ship. London, Constable & Co., 1913, p. 229.

PHOTOGRAPHIC AND MECHANICAL

PROCESSES IN THE REPRODUCTION

OF ILLUSTRATIONS

By ROBERT STEELE

There are very few books or articles which would not be the
better for a certain amount of illustration, while on the other
hand there are very few authors who could not suggest illustra-
tions or produce them themselves. Unfortunately, the steps
that lie between the rough sketch, the photograph, or the
water-colour drawing as it lies in the author's portfolio, and
the finished illustration as it is to appear in the book, are a
mystery to him, and he has no means of deciding what kind
of illustrations he can get from the material he has by him.
It is with a view of helping such an one to decide this ques-
tion that the following survey of modern methods of production
has been written.

All mechanical reproductions to-day are based upon photo-
graphy. The ordinary process of taking a photograph depends
on the use of a lens to form a clear image of the object to be
photographed on the surface of a film at the back of the
camera. This film contains a compound of silver, which is
altered by the action of light so as to become insoluble in a
liquid which we call the " developer." The tones of the picture
on the sensitive film are thus represented by the varying
thicknesses of altered silver, and after the plate has been
sufficiently immersed in the developer, all the unaltered silver
is dissolved out, and a reversed picture or negative is left on
the film, in which the lights of the real picture are black and
the shadows are light.

Line Blocks

When the illustration required is in pure line, as, for example,
a diagram or a drawing, the process of reproduction is compara-
tively simple. A negative is produced in the ordinary manner,
except that it is reversed in a well-known way by a mirror. A

153

'54

SCIENCE PROGRESS

highly polished sheet of zinc is covered with a film of albumen
treated with bichromate of ammonia, and a print of the negative
obtained on it. In the negative the lines of the original drawing
are absolutely clear, and the remainder is dense ; in the resulting

Specimen of an illustration reproduced by line process.

From an illustration by F. H. Jackson in Rambles in the Pyrenees.

print the lines are hardened by the action of light, while the
remainder is unaltered. The plate is then taken into a dark
room, inked with a roller, and allowed to soak in a bath of cold

PROCESSES IN ILLUSTRATIONS 155

water till all the unaltered albumen is sufficiently softened to
allow it to be easily wiped away, and nothing is left but the
hardened ink-covered lines. Asphalt is then dusted on them,
and gently heated till it melts and forms a protective covering
for the lines of the design. The plate is then varnished on its
back and sides and immersed in acid, which eats away its surface
except where it is protected by the film. During this process
ink is continually being added to the lines to protect their sides
from being undercut by the acid. When a sufficient depth of
zinc has been removed, the lines of the drawing stand high above
the surface, and form the block, which is then mounted on wood
or metal to raise it to the level of the type with which it will
be printed.

A drawing for reproduction in this manner should be made
with a good black ink on white paper. It is essential that the
ink should be of the same colour throughout. Chinese white
should never be used to correct the drawing, as it comes out
grey in the photograph : a "process" white for use in its place
is sold by colourmen. The cost of an ordinary block is from
2\d. to 6d. the square inch, with a minimum price of 2s. 6d. to 6s.
The variations in price correspond to the difficulty of the
subject and the technical skill of the workman employed in its
reproduction : the lower prices only applying to the very
roughest work.

Half-tone Blocks

An ordinary photograph contains, besides its pure white high
lights and deep black shadows, a very large number of inter-
mediate shades of light, called technically " half-tones," which
cannot be adequately reproduced in a line block, and for which
the half-tone process is used if cheapness is desired, while, if
better results are necessary, photogravure or collotype processes
should be employed. The fundamental difference between these
methods is that in the first the difference of tone is obtained by
the varying size of the white spaces scattered over the reproduc-
tion as seen by a powerful glass, in the second by the amount of
ink deposited in each part of it from the plate.

An ordinary illustration in a magazine, looked at through
a magnifying glass, is seen to be made up of a large num-
ber of black dots of varying size but uniform distribution.
When the dots are large and run into each other, leaving

i 5 6 SCIENCE PROGRESS

small white spaces among them, we get shadows; when they
are small we get lights. This effect is produced by intro-
ducing into the camera, just in front of the sensitive film, a glass
plate cross-ruled in parallel lines from i/5oth to i/20oth of an
inch apart.

As the picture from the lens passes through the little squares
of the ruled screen, thousands of minute cones of light are pro-
duced. Where the bright part of the picture falls on the sensitive
plate there is greater action, where the darkest parts fall there is
often very little, and thus some of these minute spots of altered
silver in the negative may meet each other on the sensitive film,
while others do not. In this way the varying size of the white
spaces which produce the half-tones is obtained.

The negative, when ready, is printed on a highly polished
piece of copper which is coated with fish-glue treated with
bichromate of ammonia, and the unaltered parts of the print
are washed away as in the case of the line block. The plate
with its gelatin picture is heated until the lines and dots, now
insoluble in acid, adhere firmly to the metal, and is then placed
in a bath of ferric chloride, which etches away the unprotected
surface and leaves the lines and dots standing free. The first
etching is a rough one, and, to bring out contrast, it is usually
necessary to re-bite portions of the plate several times, the
remainder being protected from the bath by coats of varnish.
In cases where special care is required, handwork engraving on
the block is resorted to, but this adds greatly to the expense.

Photographs of every kind, sepia sketches, black and white
wash drawings, chalk drawings, line engravings, mezzotints, and
photogravures can be reproduced to great advantage by this
process. A pencil drawing hardly ever makes a good reproduc-
tion. The chief objection to the half-tone block is that it cannot
reproduce the actual range of the artist's expression. A pure
white is impossible without engraving on the block, and light
tints are degraded by the screen lines, robbing the print of
brilliancy.

When an oil-painting or water-colour sketch is to be repro-
duced, a new difficulty arises. Colours affect photographic
plates in a very different way from that in which they strike
the eye. The yellow in a picture will come out as black, while
the blue will act as a white would. To obviate this difficulty,
either special plates which give approximately equal values to

Specimen of a photograph reproduced in three different screens, in 65, ioo, and 175

to the inch.
156]

PROCESSES IN ILLUSTRATIONS 157

the colours are employed, or in extreme cases colour filters are
used to lessen the importance of the predominant one.

The ruling of the screen used in making the original nega-
tive is of importance. In ordinary newspaper illustrations the
lines run 60 to the inch, in magazines they run 133 or 150 to
the inch. The finest screen in general use is 175 to the inch.
It would be impossible to print from a block with such fine dots
as these on any ordinary paper, as the result would be a blur.
A specially smooth surface is required : this can only be obtained
by the use of paper which has been faced with china clay paste
by being passed through a bath of the material and rubbed in by
metal brushes to attain a high polish. As a result, not only is
the eye wounded by the glistening smoothness of the paper on
which the illustration is printed, but there is a certainty that
the paper will fall to pieces in a comparatively short number of
years, as some of the earliest specimens of it have already done.

The question of the proper illustration of a book is largely
a question of expense. From every point of view it is better
that the illustrations should form part of the book itself, and not
be inserted later. The process of insertion brings an added
cost ; there is always a risk of loss of the inserted plate ; it is
usually inharmonious with the body of the work ; it is, in short,
an excrescence on it. The ideal illustration for a printed book
is a wood engraving, whose capabilities in skilled hands are
hardly to be over-estimated ; and a line block can be printed
with the text in a very satisfactory way, but all other pro-
cesses require separate printing. The objection to the half-tone
process — that it destroys the unity and durability of the book-
is one that has not been overcome, and promises to cause its
supersession.

The expense of an ordinary half-tone block from a coloured
original varies, of course, with the amount of work put into it —
say from 5^. to gd. per square inch, with a minimum charge for
12 square inches. When there is much cutting away to be done,
the minimum cost would be much higher.

Collotype

Collotype or phototype is a very satisfactory process of
reproduction of which examples are familiar to every one in the
best picture postcards. The preliminary expense of their repro-
duction is small. A rough film is spread upon glass, and on

r 5 8 SCIENCE PROGRESS

this is laid a second film of gelatin treated with bichromate of
potash. An image is printed on this through a reversed nega-
tive, in which each part is hardened in the ratio of the amount
of light that passes through the negative.

To use the film for printing it must be kept at a uniform
degree of moisture. The hardest parts absorb none, the others
absorb moisture in the ratio of the action of the light on them.
When an inked roller is passed over the film, the ink is taken
up freely by the hard, unmoistened parts, while the other parts
take it up in inverse proportion to the moisture they hold, and
print off an impression exactly reproducing the values of the
original photograph. In the hands of an experienced printer
this process gives very artistic results. One great advantage of
the collotype is that it can be printed on any printing paper. It
is especially suitable for use in the cases of small editions, as the
prime cost of making a block is avoided.

It is usual to obtain an estimate in this process for making
the collotype and printing of the reproductions together, as the
success depends equally on the character of the original negative
taken and on the skill and experience of the printer.

Photogravure

Photogravure is the most important of the mechanical repro-
ductive processes, and the most costly. A photogravure plate,
when completed, resembles the old mezzotint, in which the parts
that yield the impression are hollows in the metal, instead of
being ridges on it, as in line or half-tone blocks, or flat surfaces,
as in collotype and lithography. It is excellent for portraiture,
and gives the nearest approach to a facsimile reproduction in
black and white that has yet been obtained, chiefly because it
provides a mechanical basis on which an artist may work.

In this process the first thing required is to produce a grain
on a highly polished copper plate, for the purpose of holding
the ink. This is usually done by exposing the plate to a dust-
cloud of bitumen, and then heating it sufficiently to attach the
particles to it without entirely melting them. The plate is then
covered by the usual film of bichromatised gelatin, and printed
with the subject required from a " positive" — that is, a glass film
in which the lights are transparent and the shadows dark. The
ordinary hardening process takes place, and the unhardened
gelatin is washed away. The plate is now bitten in with ferric

SPECIMEN OF AN ILLUSTRATION PRINTED IN COLLOTYPE.

(jTh*,**' ft k«$" ftl**?y -j***uis

■y

m : %

■ ■

I ■

*•*

THE DAUPHIN FRAN'

From -CHANTILLY IN HISTORY & ART" by Mrs. J. P. RlCHTER.

PROCESSES IN ILLUSTRATIONS 159

chloride, which eats through the gelatin on the plate, its
action being carefully supervised by the workman in charge.
It is obvious that there is little mechanical certainty in the
working of this process, and not uncommonly several plates
have to be made to get a successful result. Each reproduction
has to be printed separately, as all copper and steel plates are,
and it is usual to employ a thick paper called " plate paper."
In printing the paper is damped, and forced into the hollows of
the plate, which has to be inked and wiped by hand. The cost
may be assumed as a minimum of from two to three guineas per
plate for a crown or demy 8vo book, according to the difficulty
of the subject and the skill and standing of the engravers who are
employed to finish the plates. Among these latter are, at least
in the case of one firm, exhibitors at the Royal Academy.

Colour Processes

If it is desired to reproduce an illustration in its original
colours a variety of processes are now at command. Though
chromo-lithography with a dozen or more printings for each
plate was, up to the last twenty years, the only means of re-
producing a picture, at the present time very good results are
obtained by the three-colour process, which is founded on the
fact that by the combination of the three primary colours — red,
green, and violet — any other colour may be produced. A pig-
ment must be distinguished from a colour : it is a substance
which absorbs all the coloured light that falls upon it, except
its own. The primary pigments are yellow, red, and blue, and
a perfect combination of them should produce black, just as a
perfect combination of primary colours should produce white.
If, therefore, three photographs could be obtained, one showing
only the blue elements of the coloured object, a second showing-
only the red, and a third showing only the yellow, and im-
pressions from each of them in a pure pigment combined into
a single picture, the colours of the original would be repro-
duced. All modern colour processes may be said to depend
on this principle.

In the ordinary three-colour process three half-tone blocks
are made, one each for the yellow, red, and blue, all the other
colours being strained off by a light filter in the camera as each
negative is being made. The manufacture of the negatives
requires the most skilful manipulation, and the slightest defect

1 60 SCIENCE PROGRESS

or inaccuracy is fatal to a good result. When the blocks are
completed proofs are taken, which are supplied with them to
the purchaser. These are usually a proof in the proper yellow
ink of the yellow block, a progressive proof of the red block
in red, and another of it superimposed on the yellow impression,
and of the blue block in blue, and another as printed over the
yellow and red. Between each of these printings several hours
must elapse. These proofs are the models for the colour printer
to work up to.

When making water-colour sketches for reproduction the
drawing should be kept within well-defined limits, avoiding
vignetting. The colours should not be mixed with white, and
Chinese white should never be used for the high lights.

With good blocks and good printing every colour and every
shade of colour in the illustration can be reproduced with great
exactness, though any three fixed colours will not suit equally
all subjects, while the paper on which it is printed must have
been in store for a considerable time to become thoroughly
seasoned.

The price of blocks made from a painting or sketch may
be taken as about 35. per square inch (15. each block), with a
minimum of about £3. If the photographs have to be made
directly from the objects themselves the cost would be at least
one-third more, say 4s. per inch.

The principle of making three negatives by the light filters
for the primary pigments can be applied to the collotype process
with the most exquisite results, some of the most artistic repro-
ductions of the day being made by pure collotype methods.
Coloured photogravures, like engravings, are inked in colour
by the hand on the plate itself, and are so extremely costly as
to be usually out of the question for book illustration.

Lithography

Before passing to some modifications of the colour processes
in use we must glance at the method of lithography. By it we
are able to produce facsimiles of drawings made on a prepared
transfer paper, or directly on a surface of zinc or stone. The
drawing is made with a fatty substance, which combines with
the surface of the stone, which is then damped. When an inked
roller is passed over the stone the lithographic ink does not
adhere to the moist parts, but only to the dry marks of the

A Three-Colour Block in

Yl I.LOW BLOCK.

(b> YELLOW AND RED BLOCKS.

t*,* * h

various stages of Printing.

o
3

A
it

to"

X
5L
ST
3

-1

70
Z

>
1
i
3

PROCESSES IN ILLUSTRATIONS 161

drawing. The stone is then passed through the press, the ink
is printed off on the paper, and the stone is ready for a new
impression. Coloured inks may be used.

A lithograph can be made to give great variety of tone if
its surface is roughened, or given a grain, as the grain on the
stone repels moisture in proportion to the amount of ink upon
it, and so gives accurately all the intermediate tones of the
drawing.

In photo-lithography a negative— line or half-tone — is printed
on a transfer paper made sensitive by a coating of bichromatised
gelatin. The paper is then rolled with transfer ink and placed
in a bath of water, where the unaltered gelatin softens and can
be wiped away, leaving the print upon the paper, which can be
transferred to stone in the ordinary way.

In chromo-lithography a separate stone is provided for each
colour, and the artist draws each by hand, adding new tints as
the work approaches completion. The usual number of stones
for posters or commercial work is seven, but as many as fifteen,
and sometimes twenty, may be employed in the finest work.
The difference between the chromo-lithograph and the three-
colour process is that in the former the artist's eye essays to do
what is automatically performed by the light-filters in the
camera.

Photo-lithography is especially useful for the reproduction of
large work, such as charts, diagrams, architectural drawings, etc.,
as for any small edition it is cheaper than a line block of the
same size.

Combination Methods of Colour Printing

Many very pleasing effects are produced by a combination
of various methods. It is quite usual to print the colours of a
reproduction by lithography and then to print the subject over the
colour either from a collotype or from a half-tone block. This
process is used in many of the most effective of the coloured
postcards of the Continent. Line blocks are sometimes used
when a block of solid colour has to be added to a design.

In cases of special difficulty in three-colour reproduction it is

not unusual to use a fourth block of a grey or light black tone

to produce a softening effect, while when it is not desired to

reproduce natural colours, but to make an effective picture, very

i62 SCIENCE PROGRESS

good results are obtained by using a two-colour process by
which a warm tint is added to the original half-tone block.

Other combinations are sometimes found necessary to pro-
duce the best effects or to remedy the faults of the original
drawings, but all such cases add very largely to the cost of
reproduction, and can only be suggested by the experience of
the blockmaker.

Large Impressions

Of recent years photogravure printing has been applied to
the production of large impressions in what is known as the
Rembrandt intaglio process. In ordinary photogravure printing
the plates are filled with ink and wiped by hand, and the paper
is put over the plate. In this process the plate is prepared with
a coarser grain than that of the bitumen dust, obtained by the
use of a very fine screen negative. The plate is bent into a
cylinder, which rolls over the paper, and leaves a print upon it.
The cylinder is inked mechanically and wiped as it revolves
under a series of flexible knives which scrape the ink from its
surface without removing any from the hollows. It will be seen
that this is only possible when the cylinders are turned absolutely
true and the machinery is perfect. This process in one form or
another is now being adopted by a number of weekly news-
papers for their more important illustrations, and an illustrated
newspaper abroad is entirely produced by it. The prints at
their best are softer and smoother than ordinary photogravures,
but lack their brilliancy and depth. The great initial cost of the
process is, however, a barrier to its use under present conditions,
unless a very large number of prints are required. An initial
cost which when spread over 100,000 copies is trifling is pro-
hibitive when only 1,000 are required. It is a process which
will certainly play a great part in the book illustration of the
future. Colour tints are often added to it by combination with
other processes.

Offset Process

Another process which seems destined to affect the illustra-
tion of books is the " offset " process. An ordinary offset is
caused when the impression on one sheet of paper is imprinted
on another facing it ; it is usually due to over-inking. In this
process the impression from the block and the type is not made
on the paper directly, but on an india-rubber plate or c} r linder ;

PROCESSES IN ILLUSTRATIONS 163

and it is from this impression that the actual printing on the
paper is made. The offset process is especially useful in the
case of photographic work ; the rubber fits itself into the grain
of the original block and takes off every particle of ink, which
it deposits on the paper. By it reproductions of the finest half-
tone blocks, either in black or three-colour, can be obtained on
ordinary paper. It is also used to advantage with lithography
in which a small loss of sharpness and brilliancy is not so
apparent. At present it can hardly be used for book printing,
because it tends to soften the outline of the type-impression,
which should be as sharp and clear as possible, but it is possible
that this objection may be overcome.

As regards the prices here quoted, it is important to
remember that they are mere approximations, and that it is
not unusual, for example, to find that the photographs,
drawings, etc., sent in have to be re-made in order to get a
good reproduction. In such cases the prices will be much
larger.

NOTES

Proposed Union of Scientific Workers

We continue to receive replies to our notice regarding the

emoluments of scientific workers ; and they emphasise the

opinions which have already been expressed in the leading

article of the April number of this Quarterly. For example,

one worker, a London graduate with first-class honours, who

has published original research work, and is now a demonstrator

working two or three days a week, and who also gives two

courses of post-graduate lectures with demonstrations, and does

other work, receives the generous salary of fifty pounds per

annum — much less than most unskilled labourers will work

for. We hear that in one British university, out of two

hundred members of the junior staff in all departments (that is,

all members of the teaching staff who are not full professors),

not more than six receive a stipend greater than two hundred

and fifty pounds a year. There appears also to be some fear

amongst junior staff workers that if they divulge particulars

of their salaries they will lose their posts ; and in one case we

are informed that some highly specialised workers seem even

to have lost the ambition ever to earn a reasonable wage. In

addition to the poorness of the pay, complaints are made

regarding the entire absence of any provision for adequate

pension, and also regarding the state of serfdom in which men

of science are kept under boards and committees composed of

persons who frequently have no qualifications for the exercise

of such authority. The whole picture is a melancholy, not to

say a disgraceful, one for so wealthy a country, which also

imagines that it possesses the hegemony of the world. On the

other hand, much sympathy is expressed on behalf of any

endeavours that may be made to remedy these evils, and men

of science appear to be awakening to the fact that they should

attempt some combined effort in this direction. We note

especially an excellent article on the Income and Prospects of

the Mathematical Specialist by Prof. G. H. Bryan, F.R.S., in

164

NOTES 165

the April number of the Conihill Magazine, and an admirable
lecture on the Place of Science in Modern Thought by George
Idle, Esq., M.I.N.A., delivered at the Royal College of Science,
Dublin, on January 27, which suggests at least the position which
scientific work should hold in a modern State. Moreover, the
lay press is beginning to consider the subject, entirely with
sympathy for the scientific worker ; and we should like to give
special commendation to the efforts being made by the Morning
Post in its series of articles and letters published during May
and June.

The question now arises as to what had best be done under
the circumstances ; and it has been suggested that those who
wish to do so would be wise to form a union of some kind with
a programme specifically aimed at improving the position of
the workers themselves. At present there are numerous
societies which are supposed, more or less indirectly, to attend
to this very necessary work, but which certainly have not
achieved much success in it. We should therefore like to
receive any suggestions upon the subject, together with the
names of those who may feel inclined to join such a movement
if the programme ultimately decided upon meets with their
approval.

The British Science Guild

The eighth annual meeting of the Guild was held at the
Mansion House on May 22, the Right Honourable the Lord
Mayor presiding and the President, the Right Honourable Sir
William Mather, P.C., LL.D., being present. A precis of the
annual report was read by Sir Boverton Redwood, Bart., D.Sc,
showing the excellent work being done by the Guild. We note
particularly the action of the Guild with regard to the Panama-
Pacific Exposition, 191 5, the organisation of anthropological
teaching in universities, the work of the Ventilation and Medical
and other Committees — all of which is of value. Especial
mention should be given to the facts that the Guild is paying
attention to the remuneration of members of Royal Com-
missions and committees, and that the report refers to the
inquiry made by Science Progress as to the emoluments of
scientific workers. In commenting with approval upon our
leading article in April last, Nature suggests that the subject

1 66 SCIENCE PROGRESS

of it might conic within the province of the Science Guild to
deal with.

At the annual meeting Sir Ronald Ross gave a short address
on the encouragement of discovery, in which he emphasised the
point that the public omits the main consideration as regards
such encouragement by failing to pay men of science for benefits
received from them, and his address has been made the text
of a considerable correspondence in the lay press from writers
who very often agree with him. In the evening a banquet was
given at which many good speeches were made, especially a
very noble one from the President, who remarked to the effect
that after all religion was best served by a study of the beauty
of God's works. Sir William Patrick Byrne, K.C.V.O., C.B.,
of the Home Office, made some very pertinent observations on
the subject referred to in our leading article in the April number,
of the employment of scientific experts by Government without
payment, and expressed his hearty concurrence in the opinion
that payment should in future be given whenever possible. The
time appears to be propitious for a general movement towards
the betterment of scientific work in Britain, and so far as we
can judge all workers are in favour of some reform in this
respect.

Institut fur Schiffs- und Tropenkrankheiten

On May 28 the Institut fur Schiffs- und Tropenkrankheiten
at Hamburg held a ceremony in connection with the opening
of its magnificent new buildings and hospital in Hamburg. The
ceremony was attended by many delegates from abroad, who read
or delivered messages of congratulation. Amongst these there
was a message from the Right Honourable the Secretary of
State for the British Colonies, one from the President of the
Royal Society of Medicine, and other messages from the
Liverpool and London Schools of Tropical Medicine. The new
buildings and organisation of the staff show how far Germany
exceeds Britain in its management of scientific affairs. The
laboratories and hospital exhibit the newest developments in
building and appliances — both for the treatment of the sick and
for scientific investigation — on a scale which leaves the original
British Schools entirely in the shade. This is only what is
to be expected, since the Hamburg institution is paid for and

NOTES 167

maintained entirely by the State of Hamburg and the Imperial
German Government, whereas the British Schools have been
founded principally on private benefactions, nobly given, but
collected with much difficulty and over a long period of time.
The annual income of the German institution amounts to about
£20,000 a year, which is probably more than double the incomes
of both the British Schools put together. The appointments of all
the higher workers are comparatively well paid, are put upon a
national footing, and are endowed with pensions varying from
40 per cent, to 100 per cent, of salary, according to length
of service. The German Secretary of State for the Colonies
and the President of the Hamburg Senate were present on the
occasion ; and we are glad to note that the Director of the
Institute, Professor Dr. Nocht, received a special decoration
from the Emperor on the occasion as a recognition of his fine
work now extending over many years. Although the total
German Colonies in the tropics are very small compared with
those of Britain, nevertheless Germany has done more in re-
cognising clearly the importance of tropical medicine and
hygiene. Yet, as we showed in our January number, it was
really Britain which originated this great work. The efforts
of private individuals, however distinguished they may be,
cannot hope to keep pace with a well-organised and scientific
government with the immense backing of a whole nation
behind it.

The Value of Logic

At the April meeting of the Aristotelian Society there was
an interesting discussion on the value of logic both as a branch
of philosophy and as a subject of education in the university
curriculum.

Dr. A. Wolf opened the discussion by reading sections of
a long paper in answer to Dr. Schiller's well-known attacks
in " Formal Logic." He regarded it as a work of supereroga-
tion to defend the teaching of a subject which had behind it
the traditions of 2,000 years. He himself had found that
students of economics thought it more valuable than mathe-
matics. His own experience was that, for students who were
not going to study other branches of philosophy, the more
formally it was taught the better. He attempted to prove that

168 SCIENCE PROGRESS

Dr. Schiller's book showed ignorance of a number of technical
logical points.

Dr. Schiller replied and maintained his original contention
that the fundamental basis of formal logic as commonly taught
and understood was unsound. As it might conceivably be
presented there was a case lor its continuance, but in its
present incoherent state it was worse than useless. He
remarked that Dr. Wolf's accusation of ignorance was easily
answered by a careful reading of the criticised passages in
their context, and that Dr. Wolf's case was not improved by
the violence of his language.

Dr. Bosanquet gave a general support to Dr. Wolf, but
did not altogether approve of the argument from the tradition
of 2,000 years. His own experience was that the most
educative exercise for the student was not so much the
working of the formal logic as the putting of arguments into
logic.

Dr. Mercier remarked that none of the speakers in the
course of their arguments had made any use whatever of the
obverse, or the contrapositive, or the syllogism, or any of
the technical machinery of ordinary formal logic.

Mr. Carveth Read turned the discussion to the scientific
side. He remarked that the attempt to teach methodology was
not usually very successful. Most of the time of the teacher
was taken up in explaining the meaning of the illustrative
examples, that is in teaching chemistry, physics, or biology.
The students were usually quite incapable of finding other
examples for themselves.

Prof. Brough owned that formal logic, in its present state,
was open to many criticisms, but hoped that Dr. Schiller would
see that his views were somewhat too extreme.

Mr. Shelton commented strongly on Dr. Wolfs contention
that what is asserted by science should be accepted uncon-
ditionally by logic. He said that no man of science would
make such a claim. Methodology, as commonly taught, was
metaphysics and, on that basis, no special section was required.
Unless the methodologist were prepared to make some positive
addition to the concepts, methods, and results of science, it
would be better to delete the subject of methodology from the
university curriculum.

Dr. Schiller and Dr. Wolf briefly replied.

NOTES 169

The Constitution of the Atom

The discussion at the Royal Society on the " Constitution
of the Atom" on March 19 was notable in disclosing real
experimental advances of very far-reaching consequences in
the most fundamental of all problems, the ultimate structure
of matter. Sir Ernest Rutherford, in opening the proceedings,
reviewed briefly the chief new methods of attacking the problem
— the transformation of one atom into another in radioactive
changes, the phenomena observed when high-speed helium
atoms or electrons, such as the a- and /3-rays respectively,
transverse matter and either penetrate it or are scattered and
reflected by it, and, lastly, the regular reflection of the X-rays
by crystals. In addition to and distinct from the extraordinary
advance in our knowledge of the structure of the molecular or
crystalline unit of solids, the last method, by enabling the wave-
lengths of the so-called characteristic X-rays to be determined,
has thrown an entirely new light on the structure of the atoms
of which these X-rays are characteristic.

The well-known model atom of Sir J. J. Thomson, in
which negative electrons are supposed to be distributed through
a uniform sphere of positive electricity, cannot give a per-
manently stable atom, owing to the continual radiation of
energy from the revolving electrons, and, moreover, it is unable
to explain the facts met with in the scattering of a-particles.
The deflection of a very small proportion of the a-particles
through large angles by single encounters with heavy atoms
of matter necessitated the existence in these atoms of a very
concentrated charge, large in amount but small in volume.
This led Sir Ernest Rutherford to picture the atom as com-
posed of a nuclear positive charge, excessively small compared
with the sphere of action of the atom, and consisting of a
number of unit charges equal to about half the atomic mass.
A similar number of separate negative electrons are distributed
in the external shell, the precise nature of the distribution
being still an open question. This model satisfactorily explains
the observed laws of scattering of a-particles over the immense
range of conditions for which it has been tested. Recently
Marsden has studied the passage of a-particles through
hydrogen, and has found that some of the hydrogen atoms
acquire a velocity by collision so great as to be capable of
producing weak scintillations over four times the distance

i 7 o SCIENCE PROGRESS

traversed by the «-particles themselves. These results indicated
that the nuclei of the hydrogen and helium atoms must approach
during collision to within a distance of 1*3 x io~ 13 cm., or less
than the diameter usually accepted for the electron. It might
be that the mass of the nucleus was, like that of the electron,
electro-magnetic in character and was so much greater than
the mass of the electron because of this greater concentration
of the charge. On such a view the hydrogen nucleus might
be really the long-looked-for positive electron.

Results obtained in other fields showed that the charge of
the nucleus was probably the " atomic number," which usually
is rather less than half the atomic weight. The atomic number
is the number of the element in the series when all the places
of the periodic table are arranged in sequence, that of hydrogen
being one, of helium, two, of lithium, three, and so on. Recent
results of Soddy and others, based upon the chemical work of
Fleck, showed that the value of the nuclear charge entirely
controlled the chemical properties of the atom. When a radio-
element expelled an a-particle the nuclear charge was reduced
by two units, and when it expelled a /3-particle the nuclear
charge was increased by one unit. The first produced a change
in chemical nature corresponding with a change of two places
in the periodic table in one direction and the second with a
change of one place in the opposite direction. But after one
a-particle and two /3-particles had been expelled, the product
was chemically indistinguishable from the parent.

The constitution of the nucleus was a difficult problem
which might be left to the future generation of physicists, but
it was natural and indeed necessary to suppose in the case
of the radio-elements that the helium nucleus was one con-
stituent, and, possibly, the hydrogen nucleus was another.
But the theory of Dr. Bohr which attempted to reconcile the
older mechanical theor}' with the newer conception of energy
quanta undoubtedly had some relation to the experimental
facts and had achieved notable successes in accounting for the
wave-lengths of the luminous spectra of the simpler elements
and for the wave-lengths of the characteristic X-rays.

Mr. Soddy, who followed, said he had found the nuclear
atom of great help as a guide in following the sequence of
radioactive changes. It was clear that particles moving like
the a-particles, at what might be termed ultra-material

NOTES 171

velocities, revealed the atom as a nebula with a hard point
in it. But there was no known property of electricity which
would explain how a charge of nearly a hundred units could
be concentrated within a volume less than that occupied by
an electron. The theory endowed electricity with the attributes
of matter rather than explained the attributes of matter in
terms of those of electricity. The sequence of radioactive
changes and the chemical characterisation of the successive
products showed that in the last twelve places of the periodic
table, from uranium to thallium, there were nearly forty elements,
all those falling in the same place being chemically indistinguish-
able, or " isotopic." The presumption was that the same was
true in the other parts of the table where no means of detecting
it yet existed. The results threw doubt, in particular, on the
homogeneity of the element lead, but this point still had to
be experimentally settled. Apart from any hypothesis, the
radioactive evidence proved that, between thallium and uranium,
the successive places in the periodic table corresponded with
unit increases in the positive nuclear charge of the atom. A
model was shown of the periodic system of the elements
embodying, in the well-known "figure of eight" arrangement
of Sir William Crookes, many new features in accordance
with the actual state of our knowledge of the elements to-day.
Mr. Moseley then contributed a most valuable set of entirely
new results for the values of the nuclear charges of the elements,
as determined from the wave-lengths of their characteristic
X-radiation, which fully bore out and extended the conclusions
drawn from his initial examination, by this method, of the
elements between calcium and zinc, the results of which were
published as recently as last December. Accepting the nuclear
charge of aluminium as thirteen as the basis, the wave-lengths of
the characteristic X-rays of all the others correspond with their
atomic numbers, that is, to the number of the place assigned
to them by chemists in the Periodic Table. Gaps were indicated
in the sequence corresponding with the two missing homo-
logues of manganese, between molybdenum and ruthenium
and between tungsten and osmium. In the rare-earth group,
places for sixteen elements, including lanthanum and cerium,
were indicated, instead of the fourteen included in the Inter-
national List of Atomic Weights. The work extends our
knowledge of the absolute value of the nuclear charge almost

i; 2 SCIENCE PROGRESS

from one end of the periodic table to the other, from aluminium
right into the region of the heaviest elements, worked out by
radioactive methods. The total number of distinct chemical
elements between hydrogen and uranium is probably ninety-
two, and not more than five or six of these remain still unknown.
This is an extraordinary testimony to the completeness and
thoroughness with which the elements have been investigated
by chemists.

The discussion was continued by Prof. Hicks, who, whilst
accepting in general Soddy's theory of the existence of isotopic
elements identical with one another in chemical character,
pointed out the difficulty in supposing that such elements
would prove to be also spectroscopicalty indistinguishable. He
had shown that the atomic mass enters directly into the series
relationships of spectra. The lines of the very complicated
spectrum of thorium, for example, might in some cases be really
due to ionium, which would explain the apparent identity of
the spectra of ionium and thorium.

Prof. Nicholson, in a mathematical criticism of the nucleus
theory and especially of Bohr's hypothesis, made an interesting
reference to coronium, the spectrum of which he had found
could be derived accurately on the view that the nuclear charge
was five, or the same as that possessed by the terrestrial element
boron. He suggested that coronium and other stellar elements
might have a type of nucleus entirely distinct from that of the
terrestrial elements, and possibly these elements belonged to
a different stage in the general evolution of matter. Certainly
there is no room in the periodic table, as now understood,
for any of the supposed stellar elements, asterium, coronium,
nebulium, etc. Prof. Silvanus Thompson raised the question
of the magnetic properties of matter and the magneton hypo-
thesis, and referred to recent researches of Weiss, which indi-
cated that the magnetic properties of the elements differed from
one another in such a manner as to be capable of expression by
a set of integral numbers. Mr. Allen brought forward some
interesting results obtained in the mathematical theory of the
nuclear atom, and Sir Ernest Rutherford very briefly replied.

Municipal Insanitation

The report upon the state of public health ot the city of
Dublin during 1912 issued by Sir Charles Cameron, the Chief

NOTES 173

Medical Officer of Health for the city, does not convince
the reader that the Dublin Corporation manages its sani-
tary matters very effectively. The housing of the poor
appears to be in a wretched condition, and the reason for this
is probably that the Dublin Corporation is much influenced
by the slum landlord, who is generally a man who tries to
get as much out of his property as possible — a common thing.
Apparently the corporation seldom compels him to expend
money on repairs and on sanitary improvements. The infant
mortality in the slums is very great, and the total death-rate
of the city was as high as 37*8 per thousand in 1880. During
the last ten years it has fallen to 24*8 per thousand — while in
London the annual rate is only about 14 per thousand. Even
in the North Dublin Union Workhouse, where one would
expect proper sanitation, the arrangements appear to be very
unsatisfactory. Recently a very strong report on the subject
has been issued by a deputation of working men from Man-
chester, who describe the slums as being of " incredible
squalor" {Morning Post, May 11, 1914).

It is not possible to say whether the sanitation of Dublin,
bad as it appears to be, is very much worse than that of
many towns in the United Kingdom. Certainly it is not
worse than that of many towns in British colonial possessions.
The subject is one of very great importance, because it is
open to question whether municipal government is not granted
too easily to populations which seem scarcely competent to use
it properly. The theoretical considerations upon which such
powers have been given are perhaps sound. It is supposed
that in an ideal State every person will possess political
morality and political wisdom ; and even where this ideal is
not reached, that municipal government will exert an educating
effect upon the people. But, in the world as it is, a very
small proportion of the public possess both political morality
and political wisdom. Even if many are entirely honest, few can
possibly have the detailed knowledge of municipal administration
which fits them to conduct such administration in the council of
their municipality. This must especially be the case in very
small municipalities; and the result is that in them we often find
all sanitary matters to be in a deplorable condition. One can
understand that a great city will possess enough competent
citizens to regulate its sanitary administration ; but this becomes

1/4 SCIENCE PROGRESS

more and more unlikely with smaller towns — and we can often
see municipal government granted under British administration
to what are really mere villages. In such, the management falls
into the hands of those who know nothing about scientific
administration, and, very often, into the hands of those who seek
election only for personal purposes. Thus the funds are in such
places allotted very inexpertly or upon the principle of " graft."
As nothing is more generally unpopular than sanitation, this
important branch of administration is neglected ; slum owners,
fraudulent food vendors, worthless contractors, and jobbing
tradesmen and private citizens are allowed full scope ; and the
death-rate mounts up into the thirties per mille.

It is time that the whole of this question of granting municipal
government to such bodies should receive the careful considera-
tion of Parliament and of the great machinery of Imperial
administration. Incompetent municipalities become a danger to
the State, and annually sacrifice through ignorance more human
life than may be destroyed in a chronic state of war — causing
death and sickness to untold thousands. It is extraordinary
that this state of things should continue to be allowed. If one
city can reduce its death-rate to 14 per mille, other cities can
certainly reduce theirs to a figure not much higher ; and when
they do not do so, it is generally their own fault. We should not
think of giving local judicial powers of life and death to small
municipalities — and even the police are generally removed from
their influence ; but British administration does not hesitate to
allow them much greater powers of life and death in the sanitary
line.

The remedy is to keep and to use full powers of censure and
even of suppression against municipalities which show a high
death-rate, or which exhibit incompetence in other lines. That
this can be done even under present laws is certain ; and in fact
sanitary administration has actually been recently taken out of
the hands of one municipality, namely that of Freetown, Sierra
Leone. For years that body failed to make a sufficient reduction
in the malaria which abounds in the town, though several
expeditions were sent in order to instruct them regarding the
full details of the work. The same thing can be said regarding
many other such bodies in British tropical possessions. It is
time that more discipline and science were introduced into
British administration generally. We are too lax, and give in

NOTES 175

on every occasion to the half-educated, to the wire-puller, and to
the faddist. It seems a great thing to talk about the Pax
Britannica ; but, as a matter of fact, this is often won by such
subserviency. So-called political liberty is justifiable only when
it is accompanied by efficient administration, and civilisation is
now advancing too fast to allow politicians any more to maintain
that the first is superior to the second. In fact, in the opinion
of many the whole idea of popular government requires some
revision in the interests of the life and prosperity of those who
are supposed to govern themselves, but are really too often
governed by self-seekers, talkers, impostors, and wholly ignorant
persons.

REVIEWS

The Viscosity of Liquids. By A. E. Dunstan and F. B. Thole. [Pp. vi +
89, with diagrams.] (London: Longmans, Green & Co., 1914. Price 3J. net.)

This book is a useful addition to the monographs on Inorganic and Physical
Chemistry edited by Prof. Findlay. The text is divided into nine chapters, of
which the first is devoted to the " Development of a Working Formula," the next
three to a discussion of the methods used in measurements of viscosity. The
subsequent chapters deal with liquid mixtures, electrolytic solutions, and colloids,
and with the relations which have been found between viscosity and chemical
constitution.

It is unfortunate that the large amount of research which has been carried out
in this field has provided little more than a collection of disconnected facts.
In the book under review attention is drawn to a number of relationships which
have been found to exist between viscosity and chemical constitution, such as
the definite influence of certain chemical groups, and to experiments indicating
that chemical combination is accompanied by maximum values of the viscosity.
However in none of these cases has any attempt been made to give a physical
interpretation of the results, though a few hypotheses have been thrown out, such
as the statement that the influence of the hydroxyl group in raising viscosity is
no doubt intimately connected with the potential quadrivalence of the oxygen
atoms inducing association. The viscosity of a series of unsaturated organic
compounds is also vaguely referred to the degree of residual affinity in the
compounds.

The discussion of the influence of temperature is limited to the consideration
of a number of empirical formulae to which no theoretical basis has been assigned,
and no attempt is made to justify the general practice of referring all comparative
measurements of viscosity to the values obtained at the boiling-points of
the liquids.

In the chapter dealing with electrolytic solutions, the data have been presented
in a form showing the significant relationships which may be expected between
viscosity and the condition of the ions in solution, such as their degree of
hydration and the extent of molecular association. It is very noteworthy that
at the present time no rigid relation has been established between viscosity and
any other physical property.

The disconnected nature of the results in this field render the compiling of
a monograph on this subject a task of considerable difficulty. In spite of this,
the authors have contrived to write a very readable book, which gives a good idea
of the present state of this branch of physical chemistry. J. N. P.

Intermetallic Compounds. By Dr. Cecil H. Desch. [Pp. vi + 116, with 17
figures.] Monographs on Inorganic and Physical Chemistry. (London :
Longmans, Green & Co., 1914.)

Those who know the author's " Metallography " will require no assurance as to
the merits of this, its junior partner. The present volume is small, but in it is

176

REVIEWS 177

embodied a very large bulk of work ; and it is only by reason of the skill with which
they are presented that the facts can be brought into so narrow a compass without
confusion. The subject-matter lies for a great part beyond what was discussed in
the larger volume referred to ; hence, although there must be some overlapping
between them, the two books should be taken together. Here are few experimental
details, but it is evident that all results have been submitted to the author's keen
criticism before being admitted. The aspect of the subject discussed in this volume
is one which will greatly interest chemists, quite apart from metallographers.

I. M.

The Synthetic Use of Metals in Organic Chemistry. By A. J. Hale, B.Sc,
A. I.C. [Pp. xi + 169.] (London : J. A. Churchill, 1914. Pricey. 6d. net.)

This is a book which should make its chief appeal to the practitioner of organic
chemistry rather than to the student, but there is much which is of value to both.
To the student it is (or should be) a matter of minor concern whether a given
organic process works better with, let us say, barium hydroxide instead of calcium
hydroxide, unless the fact illustrate some fairly wide matter of principle. To the
researcher, on the other hand, such knowledge may be vital.

The book is divided up in a way which seems a little arbitrary, although the
author's experience must presumably have found it to be the best ; thus the
chapters are arranged according to the various kinds of metals employed. By this
method quite different processes are often classed under one heading, and also
essentially similar processes are scattered among different chapters simply because
more than one kind of metal can be used. Thus reactions of zinc alkyl compounds
are in Chapter IV., whilst the corresponding magnesium Grignard reactions are in
Chapter III.

The subject-matter is not limited to the metals themselves, but is extended to
include their inorganic compounds. One result is that under " Sodium and
Potassium" we find such diverse and unrelated reactions as those of metallic
sodium on alkyl halides, potassium cyanide on ketones, and potassium hydroxide
on aldehydes.

From the point of the student (for whom the work was chiefly written) this book
is useful in showing what a very large bulk of all manner of organic syntheses is
effected by the use of metals and metallic compounds, and it also provides numer-
ous well-selected practical examples to be worked on in the laboratory. The book
will also prove convenient for original workers and for teachers who wish for
material to exemplify their own systematic treatment of organic synthesis.

Quantitative Analysis in Practice. By John Waddell, D.Sc, Ph.D., etc.
[Pp. vi + 162.] (London : J. A. Churchill, 1913. Price 4s. 6d.)

This is a book which ought to prove very useful to students beginning quantitative
chemical analysis. Primarily, it forms an introduction to technical methods, but
this really adds to its value as an aid to those who take up the academic side ; for
of the three essential factors in technical work which are neatly summed up in the
introduction as honesty, accuracy, and speed, the first two are always to be insisted
upon in " pure " chemistry, whilst the third is often apt to receive too little attention.
Further, most teachers noticevthat students are often more interested in analysing
everyday substances than in performing similar operations upon pure chemicals ;
accordingly, here we find the examination of clay, cement, coal, iron ore, and such
materials forming a great part of the book. The accounts of the principles, no
12

178 SCIENCE PROGRESS

less than of the detailed practice, of analyses, are very carefully and clearly given,
and the student is not ordered to take a given precaution without being shown
exactly why he should do so. In fact, the whole scheme is rational and satisfactory,
and there are a great many features, such as the indication of the time for each
analysis, which lend special worth to the book.

I. M.

Photochemistry. By S. E. Sheppard, D.Sc. [Pp. ix + 461. Illustrations and
figures.] Text-Books of Physical Chemistry. (London: Longmans, Green
& Co., 19 1 4. Price 12s. 6d.)

IT is no easy matter to review a book like this ; for the reviewer cannot claim to
be an authority on photochemistry, hence he feels some diffidence in expressing
views which are in the nature of unfavourable criticism. No such criticism would
be offered if the series of which this book is one were designed for the reading of
specialists only ; but the volumes already issued appeal to a wider public, and
therefore it is legitimate to regard the work from a not too exalted standpoint.

Firstly, the treatment throughout is of a very physical kind, and although
obviously a great deal of photochemistry is pure physics, a more chemical outlook
upon it than we find here would have been welcome. The chemical reader wishes
to have, in the first place, information as to the facts of the reactions set up or
modified by light, and he expects that information to be conveyed in ordinary
chemical phraseology. He is then prepared for whatever theories and hypotheses
may be forthcoming as to the reasons for such actions, together with the further
facts, chemical and physical, which lend support to these. This is doubtless a
limited aspect of the matter ; but the point is that this limited aspect is photo-
chemistry, in which science physics must play an auxiliary and not a preponderating
role. In this book there is a large amount of extremely interesting matter, but its
relevance to chemistry is not always plain. And although by diligent study the
reader will come to an understanding of what is set forth, he will find that con-
siderable rearrangement, including discrimination of well-grounded theories from
speculation and analogy, occupies much of his time after reading.

It would be presumption to deny that an author whose knowledge is as profound
and whose enthusiasm is so great as Dr. Sheppard's has the right to choose his
own way of attacking his own subject, even though the result may turn out to be
caviare to the general. But (and this is the last criticism) it seems to the writer a
vast pity that so much interesting and stimulating material should be set forth in a
style which jars constantly upon the literary sense of an ordinary individual, and
which by its obscurity (in reality due to a meticulous regard for the mot juste) is a
real check to the appreciation which the author surely should receive.

It must be insisted on once more that these remarks represent the views of a
chemist only ; those who specialise in the chemical effects of light cannot fail to
gain by the collection together into one volume of so much that is significant in the
subject.

I. M.

An Introduction to the Chemistry of Plant Products. By P. Haas and
T. G. Hill. [Pp.401. With 5 text figures.] (London : Longmans, Green
& Co., 1913. Price 7s. 6d. net.)

It should be said at the outset that this book will be of very great value to
the botanist ; published at such a commendably reasonable price, it should find
a considerable public. There is no other English book in which the reader

REVIEWS 179

will find such ample treatment of the large amount of recent work upon the
chemical problems involved in plant metabolism. Most of the chief groups of
organic substances of importance in the plant are passed in review in turn, and
discussed in the first place from the chemical standpoint, and then in relation
to their role within the plant.

Strictly speaking, the scope of the book would be better indicated by such
a title as " Materials for the Study of Plant Products," as it is essentially a
compilation, and lacks that very valuable element in an introduction to the
subject, the challenging statement of current hypothesis and controversy which
leads the reader to pursue the subject further.

Regarded as a compilation, there are certain criticisms which seem to the
reviewer valid.

In the first place, in spite of the statement in the preface that a knowledge
of elementary chemistry is assumed, there is some very elementary chemical
explanatory matter in the text. It is questionable whether it is a healthy tendency
in the botanist that he should be satisfied to have one of the most funda-
mental underlying sciences of his subject presented to him entirely through
the medium of his special literature. To take a concrete case, it is surely not
desirable that the student of plant physiology should arrive at the conception
of an ester simply through a consideration of the very brief exposition of the
formation of salts which precedes it on page 5. Far better that, if the con-
ception of an ester be a new one, elucidation should be sought from general
chemical literature.

The book also suffers from one of the defects, perhaps constitutional to
compilation, that the various sections do not seem adequately welded together.
This is perhaps a defect in the subject-matter at the present stage rather than
in its treatment, but the chapter on colloids, for instance, arrives most un-
expectedly, and seems to remain very aloof from the many physiological
problems it must ultimately help to solve.

The publication of a book of this type, with its valuable references to
original papers, tends to make the reader think that the citation of literature
is exhaustive ; but papers appear on these subjects in such widely different
journals that completeness of treatment is probably impossible. In some
sections, indeed, the present work is rather misleading, owing to the absence of
reference to important papers upon the subjects discussed. The tests given for
the detection of small quantities of formaldehyde, for instance, by no means
exhaust the possibilities of the subject, and Bokorny has given a more complete
account.

In the section upon the quantitative estimation of sugars, no reference is
made to important series of investigations by Brown and Morris and by Parkin,
in which the quantitative distribution of sugars in plant tissues was studied
Their conclusion that cane sugar is to be regarded as the essential sugar in
the up-grade series also receives inadequate treatment.

The section on proteins has necessarily been so condensed that the presen-
tation of the subject is incomplete on many points. It will obviously mislead
if the few paragraphs upon the formation of salts by proteins are regarded as
an adequate treatment of the subject.

Finally, it seems clear that if books are to keep pace with the rapid progress
of the subject, it is to the special monograph, readily revised, that we must look
for accurate information. Thus it is probably hardly the authors' fault that, in
producing a work of this scope, important facts, in the light of recent work,

i8o SCIENCE PROGRESS

are already incorrectly stated. Thus the impression given on page 227 that

the best extracts of chlorophyll are obtained by the action of water-free solvents

on dried leaves is quite incorrect.

J. H. P.

A Text-Book of Experimental Metallurgy and Assaying. By Alfred
Roland Gower, F.C.S. [Pp. xiv + 163.] (London : Chapman & Hall,
191 3. Price 3^. bd. net.)

This little book is modelled on earlier editions and forms a concise and well-
arranged guide for the beginner in practical assaying and metallurgical work.
The explanatory text is very brief, and, as the author states in his preface, the
knowledge, on the part of the student, of elementary theoretical chemistry is
assumed. The first portion of the book is given over to the description of simple
experiments, such as may be carried out in any assaying laboratory, dealing with
the various processes connected with the production of metals from the oxides,
sulphides, and other compounds ; the use of fluxes and the formation of slags ;
and the formation of alloys. The second half of the work presents a series
of experiments that serve to illustrate the methods adopted for the assay of
the precious metals and for the dry and wet assays of the baser metals and alloys.

Several appendices are placed at the end of the book and comprise weights
and measures, melting-points and specific gravities of the metals, and a table
of international atomic weights. Appendix D, which occupies eight pages, is
a list of chemical formula? purporting to represent the principal reactions which
take place in metallurgical operations. It is, however, difficult to see that any
useful purpose is served by tabulating such matter as this, for the formulae are
necessarily incomplete and give no idea of the conditions under which the changes
are supposed to take place.

Appendix E gives a brief description of the chief ores and contains what might
be termed "rule of thumb" methods for their discrimination. Other appendices
comprise a table of factors and other aids in the solution of the ordinary assay-
problems.

The book as a whole is eminently practical, but the practical side has been

given so much prominence that the scientific aspect of the metallurgical methods

is somewhat lost sight of. The book, however, should prove of great value to the

elementary student if used with caution. Its use should certainly follow on a

ground-work of elementary chemistry and an appreciation of the scientific

principles that underlie and control the various reactions to which metallurgical

science owes its existence.

H. H. T.

The Antiquity of Man in Europe. Being the Munro Lectures, 19 13. By
James Geikie, LL.D., D.C.L. [Pp. xx + 328. With 21 plates, 9 other
figures, and 4 maps.] (Edinburgh : Oliver & Boyd. Price io.r. 6d. net.)

Dr. Robert Munro founded the "Munro Lectureship in Anthropology and
Prehistoric Archaeology " at Edinburgh University about two years ago, and was
himself the first lecturer. Prof- J. Geikie is thus the second scholar to hold the
position, and his ten lectures are now issued as a book which, in spite of certain
somewhat serious omissions, is absorbingly interesting from beginning to end.

It is unfortunate, however, that the lectures cannot be considered quite up-to-
date. They were delivered after the famous Piltdown discovery was made

REVIEWS 181

known to the world (though, we believe, before the Dawson-Woodward paper was
actually published), and yet they contain virtually no reference to that epoch-
making event, a fault which is aggravated by nearly a year's delay in publication.
This is the more disappointing in that there is of course no one more competent
than the author to answer the important question as to whether the Piltdown
relics — one of the two oldest discoveries of man in Europe — should be attributed
to the first or to the second interglacial epoch.

The work deals, as its title implies, with the purely geological side of pre-
historic anthropology, anatomical and archaeological matters being only referred
to so far as is necessary to make the geological story intelligible. The extreme
views on the question of the antiquity of man obtain scant recognition from
Prof. Geikie. Here we have no talk of Oligocene, Miocene, or even of Pliocene
humanity. The claims of the eoliths are dismissed in a few paragraphs, and
the Ipswich and Galley Hill skeletons are not deemed worthy of mention. Even
the Pliocene " rostro-carinate implements," championed by Ray Lankester, are
regarded as more than doubtful. The problem is thus narrowed down to the
Pleistocene, and the opinions expressed are representative of the more cautious
school of anthropologists.

The dramatic story of the Glacial Epochs is told us once again, and with a
wealth of detail which makes the book of value to the student as well as to the
general reader. We are given a vision of the musk-ox, the banded lemming
(well described as " the warmth-hater "), and other denizens of the tundras coming
south through twenty degrees of latitude, of icebergs stranded on the Azores,
and of vast Swiss glaciers boring huge trenches hundreds of feet deep. The
successive lectures deal with the Pleistocene fauna and flora, with the testimony
of the caves, the river-drifts, and the great morainic accumulations, with the
interglacial strata ; and finally a chronological history of the Pleistocene is given.
There is a thorough treatment of the flora as well as of the fauna, and both
animals and plants are illustrated by numerous charming plates. The botany of
the Pleistocene is very important, because the plants afford a more reliable index
to climatic changes than the animals can supply. No doubt in many instances,
where remains of animals apparently belonging to different climates are found
in juxtaposition, the creatures were not really contemporaneous — different strata
have become mixed up ; but this is not so in every case, and there is little doubt
that the lion and the hyena, for instance, ranged into colder climes in the
Pleistocene than they do now, and the converse appears to be true of the arctic
fox.

As is well known, Prof. Geikie's scheme includes six glacial epochs, not
four as in the more generally accepted classification. His differences with Penck
and the other great German pioneers are, however, scarcely more than verbal.
His first four epochs correspond entirely to their four, and it is not denied on the
one side that there were several subsequent returns of cold conditions, nor is it
contended on the other side that such recurrences approached in severity any of
the four great ice-ages. Moreover, it is known for certain that Palaeolithic man
and the distinctively Pleistocene fauna vanished before the fifth glacial epoch of
Geikie. It is a moot point whether the last cold phases were sufficiently severe
to be styled " Glacial Periods." There are proofs of three returns of cold
conditions in the Alps, but the first of these is indistinguishable from the fourth
glacial period in Scotland. Thus the author's first glacial epoch is evidenced by
the Chillesford Clay and Weybourne Crag, which used to be classed as Pliocene,
and his last two are Neolithic.

SCIENCE PROGRESS

The correlation of the human relics with these glacial and interglacial epochs
is an interesting if difficult subject. There is no unanimity yet among scholars,
but here, as elsewhere, the author represents the dominant school. The Heidel-
berg Jaw is placed in the first interglacial phase, and the Chellean and Acheulean
cultures flourished in the second genial interval, which was very long and warmer
than the present day. The M-ousterian implements carry us through the third ice-
age to the next interglacial epoch, at the end of which the more advanced
Aurignacian and Solutrean cultures appeared. The Magdalenians lived through
and during the decline of the fourth glacial epoch. Then comes the hiatus
between Palaeolithic and Neolithic man, which the author regards as a reality in
Northern and Central Europe, if not farther south, the so-called Azilian culture
being typically Neolithic. The Neolithic tribes appeared, however, before the
fifth ice-age. It is unfortunate that the author groups the two oldest cultures,
the Mesvinian and Strepyan, with the Chellean. The Mesvinian implements
have been placed by some writers in the first interglacial epoch, and since they
are the oldest artifacts generally recognised as such, we should have welcomed a
discussion of their exact age. We infer that Geikie places them in the second
interglacial epoch with his comprehensive " Chellean," but the point is not
discussed.

We think the anatomical summary is too meagre even for the author's special
purpose, and we find it stated on p. 47 that the Magdalenians were short. One
of the Magdalenian races no doubt was short, but there is strong evidence
(accepted by most writers) that the tall " Cro-Magnon " race was living during
this period, and Prof. Geikie ought certainly to have given his reasons for
dissenting from this view.

The book closes with the usual guesses at the duration of the various epochs

in years, the Heidelberg Jaw being given an antiquity of about half a million

years.

A. G. Thacker.

The Childhood of the World. A simple account of man's origin and early
history. By Edward Clodd. New and revised edition. [Pp. xiii 4- 240.
With 26 figs.] (New York : The Macmillan Co., 1914. Price 4s. 6d. net.)

This well-known and successful little work, first published in 1872, is divided into
three parts, dealing respectively with man's physical and material evolution,
his mental and religious development, and with his advance in scientific ideas.
The book's success (it has been translated into seven languages) is no doubt
largely due to the author's admirable style of writing, which, being both simple
and graphic, enables him to reach not only the general public but even juvenile
readers. Occasionally, however, in aiming at simplicity he becomes almost
unintelligible, as in his avoidance of the word " Pleistocene." The work of
bringing the book up-to-date has been fairly thoroughly done, but there are a
few rather serious mistakes. For instance, the erroneous impression is given
that the distribution of land and sea in N.W. Europe was almost constant during
the Paleolithic Age ; the phylogenetic tree of the higher Primates on p. 14 is
misleading and inadequate, the subdivision of the Old Stone Age on p. 50 is
quite out-of-date, and we are told that there are no fossils known from Pre-
cambrian rocks. The section dealing with religion is written from the naturalistic
standpoint. There is a good bibliography appended.

A.G.T.

REVIEWS 183

Australasian Fossils. A Student's Manual of Palaeontology. By Frederick
Chapman. With an Introduction by Prof. E. W. Skeats. [Pp. 341.
Illustrated.] (Melbourne : G. Robertson & Co., 1914.)

STUDENTS of palaeontology in Australia and New Zealand have hitherto had to
contend with the disadvantage that the text-books on their science are mainly
written either from the European or the American standpoint, and consequently
take but scant notice of Australasian formations and fossils. To a certain degree
this is undoubtedly a hindrance to local workers, and it has accordingly been
deemed that the time has come to collect and arrange in a handy form the main
facts of the subject as exemplified from the Australasian point of view. The
result is the admirable little volume now before us, the author of which, from his
official position as palaeontologist to the National Museum at Melbourne, enjoys
special and unrivalled opportunities for undertaking a task of this nature.

Not only will the volume stimulate workers in Australia and New Zealand, but
it will likewise have a very considerable value to workers in this country as an
up-to-date sketch of the leading facts in Antipodean palaeontology. The Austra-
lasian student may, however, be reminded that the publication of Mr. Chapman's
volume does not by any means imply that palaeontological and geological works
written from the European standpoint are to be permanently shelved, and that
he will find all he wants in the local text-book. As the author himself would
doubtless be the first to acknowledge, precisely the contrary is the case ; and
since the British rock series, with its included fossils, is the typical basis for the
geology and palaeontology of the world in general, students in all quarters of the
globe must always make this their starting-point and standard of sequence.

In connection with this sequence of strata in Europe and the Antipodes certain
very important and interesting remarks are made in the Introduction by Prof.
Skeats with regard to the late Prof. Huxley's doctrine of " homotaxis." Through-
out the world there is no exception to the rule that strata containing Devonian
and Carboniferous fossils overlie those of a Silurian type, and that Palaeozoic
are succeeded by Mesozoic formations, and these again by beds of Tertiary age.
But it has long been a question whether, let us say, the Silurian and Devonian
strata of Australia or Africa were strictly contemporaneous with the typical
European representatives of those strata. Huxley was strongly disposed to
consider that they were not, basing his opinion on the supposition that the
migration of one fauna — say the Silurian — from one area to the other would occupy
such a long period of time that when it reached its new habitat the succeeding
Carboniferous fauna would have developed in the original area. Consequently,
if this were so, a Devonian fauna and flora in Britain might have co-existed with
those of Silurian age in North America, and with Carboniferous forms of life in
Africa.

But, remarks Prof. Skeats, " this could only be true if the time taken for the
migration of faunas and floras was so great as to transcend the boundaries between
great geological periods. This does not appear to be the case, and Huxley's
idea in its extreme form has consequently been generally abandoned." Hence
we may now regard at least some of the Silurian fossils of Australia as being the
actual contemporaries of their European namesakes.

Commencing with a discussion on the nature ol fossils, the means by which
these are preserved, their various modes of occurrence, and the characters and
sequence of the rocks in which they are embedded, Mr. Chapman includes in
this portion of the volume a table showing the correlation between the geological

SCIENCE PROGRESS

horizons of Australia and those of Europe. A persual of this table will at once
show that while there is a comparatively full development of the Palaeozoic strata
and their fauna in the southern island-continent, the Middle and Upper Mesozoic
formations are much less fully developed than in Europe, while the Eocene is
apparently wanting. In consequence of these deficiencies, Australia has practic-
ally no record of the great development of terrestrial reptilian and mammalian
life which took place during these epochs in other parts of the world ; thereby
emphasising our remarks with regard to the importance of European pala?onto-
logical text-books to Australian workers. Before leaving the stratigraphical
table, reference may be made to an unfortunate error on p. 47, where the
Permian and Carboniferous are classed as Mesozoic in place of Palaeozoic.

The various groups of animal fossils are treated in zoological order, from
the lowest to the highest, and there is also a brief chapter on paleobotany, in
which it is mentioned that the existing ginkgo, or maiden-hair, tree of China and
Japan was represented in the Jurassic of Victoria and Queensland.

As regards their vertebrate land faunas both Australia and New Zealand come
under the category of what have been happily termed " biological asylums" —
a feature largely due to the long isolation of both areas. There was, however,
a time when Australia formed part of " Gondwanaland," and shared its thylacines
and horned-tortoises with South America, its batrachians with South Africa, and
its ferns with India ; and it would have been well, we think, had these former
land-connections been shown on a map. In regard to the systematic position of
the Australian aborigines the author is thoroughly up to date, although he is a bit
" wobbly " with regard to the introduction of the dingo.

Taken as a whole, the volume is admirably planned, and the plan admirably

executed.

R. L.

The Snakes of Europe. By G. A. Boulenger, LL.D., D.Sc, Ph.D., F.R.S.
[Pp. xi + 269. With 14 plates and 42 text figures.] (London : Methuen &
Co., 1913. Price 6s.)

Until the publication of this book there was a remarkable gap in English
zoological literature ; for, as is pointed out in the preface, there is no book
treating of European reptiles in the English language. This present volume
on the snakes in part fills the gap ; and it is to be hoped that the remaining
European reptiles will be dealt with ere long by an author as well equipped for
his task as Mr. Boulenger.

The book is divided into two parts — one an introduction dealing with the
characteristics of snakes in general, and the second occupied with a systematic
account of the various species. On the whole, the book is remarkably free from
errors ; but to make a sentence, " Further remarks on this subject in the chapter
on Dentition " (p. 6) needs some addition, and " in relation with " is used instead
of " in relation to " on p. 8. There is a tendency to use technical words not
clearly explained by the context rather freely in certain parts, e.g. Lepidosis
(p. 17), and some of the chapters are consequently rendered very stiff reading
for the layman. The chapters dealing with general subjects, such as those on
Colouration, Habits, and Snakes in Relation to Man are extremely interesting.
To crowd a large amount of information into a small compass is always a difficult
task, but it has been accomplished here with great success. The nervous system,
however, is somewhat briefly treated, and the whole of it is dismissed in about
six lines.

REVIEWS 185

The statement on p. 77 that "the right systemic arch gives off the carotid
artery, which in many snakes — the common grass-snake, for instance — may branch
into two, or in others be double from its origin," is somewhat misleading, since it
implies that in this snake there are two common carotid arteries. One of the
most interesting points in the arterial system of the grass-snake, however, is
the fact that as the right common carotid is reduced during embryonic develop-
ment to a very small twig which supplies only the thyroid gland, the whole of the
blood-supply to the head is carried by the left common carotid. Three special
arterial anastomoses are developed in order to allow the blood to be conveyed
to the right side of the head.

The key to the identification of the various species by means of their external
characters and the list of the species found in the different regions of Europe are
very handy. Although it is stated on p. 135 that the vipers are the only very
dangerous snakes, this information would be more easily referred to if the
individual species in either of the above lists had been marked according to
whether they were slightly, considerably, or not at all poisonous.

The systematic part contains a full yet concise description of all the snakes
found in Europe, together with an account of their distribution, local varieties,
and habits. This is indeed very useful for reference, and its value is greatly
enhanced by the completeness of its illustrations, mostly from the very accurate
drawings by Prof. Sordelli of Naples.

The few criticisms offered above do not alter the fact that the volume is a very

desirable addition to our knowledge. It is certainly a work that should find

a place on the bookshelf not only of the naturalist, who will learn much from its

well-filled pages, but also of the general reader who wishes to know something of

the general characteristics of snakes or the particular forms to be found in Europe

from one who has command of a facile pen and a remarkable knowledge of his

subject.

C. H. O'D.

Les Zoocecidees des Plantes d'Europe et du Bassin de la Mediterranee.

Tome 3: Supplement 1909-12. By C. Houard. [Pp. 312. With 1567
figures and 8 portraits.] (Paris : A. Hermann et Fils, 191 3. Price 10
francs.)
The vast majority of the parasites which attack plants are either fungi or
insects, and the result of the attack is either (1) a drain on the food-resources of
the host, which if severe may so weaken it that it succumbs to adverse conditions
otherwise easily overcome, or (2) the production of injurious substances which
cause local or even general death, or (3) a stimulus to local growth. As regards
(1) and (2) it may be said that general death as the result of parasitic attack is a
rare occurrence in the higher plants, only taking place when the parasite blocks
up the wood vessels, thus cutting off the water-supply to the leaves, or invades
the whole plant. In most cases, death is likely to be merely local, since plants
present a striking contrast with animals in the fact that they have no means for
the rapid distribution of poisons locally produced nor any regulatory centres whose
injury upsets the entire system.

The location of a parasite in a plant is often marked by deformities which
frequently appear as circumscribed swellings, or galls, and are usually conspicuous
structures of peculiar and fantastic or beautiful form, especially in the case of
animal-induced galls (zoocecidia). The chief animal gall-producers, apart from
the nematodes (eelworms) whose attention is usually confined to the roots of

186 SCIENCE PROGRESS

plants, are insects belonging to various families of hemiptera, diptera, hymenop-
tera, and a relatively small number of coleoptera and lepidoptera ; while the
plants attacked range from Alga? and fungi to the Compositae — indeed there are
probably very few species of flowering plants on which galls may not be found
either frequently or occasionally. Hence it is not surprising that the study of
animal-induced galls (zoocecidology) is pursued by a large and enthusiastic body
of workers, mainly field-naturalists who confine their attention to external form
and the determination of the species of insect and plant concerned in gall pro-
duction. The investigation of the histology and physiology of galls has, as might
be perhaps expected in a branch of biology which appeals both to botanists and
zoologists, and is therefore apt to be neglected by laboratory workers in both
departments, lagged behind the purely systematic study of zoocecidology, though
it offers a most attractive field for research and the results already obtained are of
the greatest interest from many points of view, both biological and biochemical.
The work of Peyritsch, Beijerinck, Kiister, and others has shown that the detailed
study of galls and gall-formation may throw light upon many problems in the
physiology and pathology of plants, and the considerable and increasing
literature of the subject indicates that this study has before it a future of great
promise.

Meanwhile, biologists owe a debt of gratitude to the labours of M. Houard in
compiling his great work, of which the volume now issued is the third part, con-
sisting of pp. 1249 to 1560, with figures 1366 to 1566. As the author points out,
since the appearance of the first two volumes the study of galls has shown extra-
ordinary development, and this supplementary volume, based on four years of
cecidological work, contains descriptions of 1,300 galls, giving the names of over
500 species of gall-producing animals and of 300 new plant " hosts," with an
extensive bibliography, and finally zoological and botanical lists which facilitate
reference to the body of the work. This volume, like its predecessors, is indis-
pensable to all who are interested in galls ; it is admirably arranged, and the price
is very moderate.

F. Cavers.

Cabinet Timbers of Australia. By R. T. Baker, F.L.S. [Pp. 186. With 68
coloured plates.] (Sydney: Technological Museum, 1913.)

This handsome volume forms No. 18 of the valuable Technical Education Series
published by the New South Wales Government, and contains an Introduction
written by the State Minister of Public Instruction, who aptly remarks that the
colour, figure, and other characters here portrayed of the various species, by
colour photography, may come as a revelation to those not intimately acquainted
with the timbers themselves. The letterpress is practically limited to brief but
adequate descriptions of the various timbers, which are illustrated by sixty-eight
exquisite coloured plates. These fine plates alone render the book of great
value ; and it is greatly to be desired that plates of this kind, showing the natural
colour and graining of timbers, may be published in other timber-producing
countries. The importance of works like this is far-reaching ; for apart from
their more immediate value in the technology of timber and in cabinet-making,
the bringing together of useful and beautiful timbers in this particular form should
do much to stimulate the movement for the setting aside of forest reserves and
for extensive afforestation in regions where valuable forests are in danger of
extinction.

F. Cavers.

REVIEWS 187

Rubber and Rubber Planting. By R. H. Lock, Sc.D. [Pp. xiv + 246, 10
plates and 18 text figures.] (London : Cambridge University Press, 1913.
Price 55-. net.)
THOUGH no other vegetable product has been put to so many and varied uses as
rubber, and none has risen with equal rapidity from insignificance to such high
commercial importance, the science and practice of rubber planting are alike, as
the author points out, still in their infancy. Dr. Lock is to be congratulated on
having succeeded in compressing into the small compass of this handy and well-
illustrated book a remarkably complete summary of what is accurately known in
both the botanical and the commercial branches of the subject. His well-known
researches on the physiology of latex, together with his close and long-continued
personal acquaintance with the plantation industry in Ceylon, render the present
work authoritative and accurate in both branches, while it is written in a simple
and attractive style which should ensure a wide circle of readers.

The subject of rubber and its cultivation is one that appeals not merely to those
connected with the rubber industry, but to all who are interested in natural pro-
ducts and particularly in one like rubber, in the development of which British
invention and British capital may be said to have played the predominant part
almost throughout. The first patent for the employment of rubber for anything
further than such uses as the removal of pencil marks dates back only to 1791,
when it was applied to waterproofing purposes by Thomas Hancock, of the firm of
Charles Macintosh & Co. ; but the modern extensions of rubber manufacture only
became possible after the discovery of vulcanisation — the process of combining
rubber with sulphur — was made, about seventy years ago, independently and almost
simultaneously by Goodyear in America and Hancock in England. In his chapters
on the chemistry of rubber and the manufacture of rubber goods the author gives
details concerning vulcanisation, which ranks among the most important of all
industrial discoveries, since it not only makes rubber practically unaffected by
changes in temperature and immersion in water, but enables the manufacturer to
vary the physical properties of the finished product, according to the proportion of
sulphur used, from those of the softest elastic up to those of the hardest vulcanite.
The importance of the rubber-planting industry to this country may be gauged
from the fact that over ^100,000,000 of British money are invested in it, quite apart
from the almost innumerable manufacturing industries in which rubber plays a part.
The author discusses the botanical sources of rubber, the physiology of latex
production, and experiments in tapping ; then follow four chapters on Hevea
brasiliensis, dealing respectively with planting and harvesting operations, factory
work on the estate, and the pests and diseases of Hevea. A chapter is next
devoted to the cultivation of rubber-yielding plants other than Hevea, in which,
after a brief but judicious summary of the results obtained from Castilloa,Manihot,
Funtumia, and Ficus elastica in various parts of the tropics, he arrives at the con-
clusion that in the future the world's supply of rubber will probably depend more
and more upon the Hevea plantations. The chapter on rubber chemistry gives a
remarkably clear and concise account of recent work on a substance whose
chemical composition and behaviour are among the most difficult problems facing
the organic chemist. F. Cavers.

The Diseases of Tropical Plants. By Melville Thurston Cook, Ph.D.
[Pp. vi + 317.] (London : Macmillan & Co., 1913. Price 8s. 6d.)

The rapid growth of plantation industries in the tropics, and the great advances
made in tropical agriculture generally, within comparatively recent years have

i88 SCIENCE PROGRESS

resulted in the occurrence of epidemic diseases of various kinds which always
tend to accompany the cultivation of individual plants on a large scale. Many
of the diseases are of fungal nature, and these are often those most difficult to
cope with. Every crop is liable to attack sooner or later, however resistent it
may appear to be on its first introduction. When tea was introduced into Ceylon
as one of the principal crops, about a quarter of a century ago, it was often said
that the main thing to be careful about was to get the right variety, as once in, it
was difficult to get out. No disease of any consequence appeared to attack
the bushes, and after the awful experience of coffee it seemed as if at last a
plant had been secured which was easily going to hold its own against all parasitic
invasion. But tea is not immune, any more than is any other crop, and as the
years go on the number of plant diseases referable to fungi continually increases
with the growth of intensive culture.

A book on diseases of hot-country plants, their nature, prevention, and
curative treatment, will appeal with force to those whose business lies in the
tropics, where cultivation is carried on under climatal conditions peculiarly
favourable to the spreading of pests of many kinds, while their eradication is
attended by corresponding difficulties.

Dr. Cook is already known as a writer on plant pathology, and his experience
in Cuba and elsewhere has enabled him to gain a first-hand and extensive know-
ledge of the subject. The broad lines on which his book on The Diseases oj
Tropical Plants is laid down are similar to those of other writers who have dealt
with the subject in connection with the vegetation of temperate climates. He
considers the general nature and symptoms of disease in general, and, in order
that his readers may be the better able to follow him, gives a brief outline of the
structure of the higher plants. This is followed by a classification of the fungi,
and a short account of the chief disease-producing animals. The greater part
of the volume is devoted to a description of the particular diseases (and the
organisms which cause them) of individual economic plants, whilst in a special
chapter the chief fungicides and forms of spraying apparatus are described.

The book is a useful one ; but perhaps it will appeal more to the scientific
expert, or the plant-sanitation officer, than to the planter. The latter will
find much that he would scarcely understand or appreciate without a previous
botanical training. It does not, however, follow that this is to be regarded as a
blemish, for, after all, plant-sanitation work is a highly expert business, and it can
hardly be undertaken by an amateur without grave risk. If one desired to urge
a point of criticism on general grounds it would be that the author seems to have
tried to cater for both classes of readers, the planter and the pathologist. Perhaps
this was inevitable. At any rate, Dr. Cook has done his work well, as far as a
book of modest dimensions would allow, and the planter will doubtless derive
much instruction from it. He will be able to appreciate the urgent importance
of extending our knowledge of a subject which touches his own material
interests so closely.

The book is well printed and illustrated, but the misprints are somewhat more
numerous than they should be.

Philosophy of the Practical, Economic and Ethic. Translated from the Italian
of Benedetto Croce by DOUGLAS AlNSLlE, B.A. (Oxon), M.R.A.S. [Pp.
xxxvii + 585.] (London ; Macmillan & Co., 1913. Price \2s. net.)

The volume translated by Mr. Ainslie is entitled The Philosophy of the Practical.
Those who are not acquainted with the peculiarities of modern metaphysics must,

REVIEWS 189

however, be warned that the title may be misinterpreted. The philosophy is not
practical in the ordinary sense of the word. In the words of the author, " The
Philosophy of the Practical cannot be practical philosophy." The author, indeed,
in some passages expresses the opinion that it is unphilosophic to attempt to
deduce a practical conclusion from a philosophical premise. The volume is an
essay in metaphysics, beautifully written, and the author is fortunate to find
a translator, himself a poet, who has so keen a sense of literary form. The
reviewer is unable to judge the accuracy of the translation, but can pay the
compliment that the volume reads like an original work.

Unfortunately, however, the translator insists on writing a preface. And the
preface attracts attention, irritates, and excites opposition. How far the author
would appreciate the remarks is doubtful. One remembers Swift's account of the
meeting of Aristotle and his critics in the truthful atmosphere of the underworld.
On the other hand, we must not forget the more practical side. If metaphysicians
were not admired by pupils who misunderstood them, 1 they would have no readers
at all. We are, however, interested to note that "the so-called Synthetic Philosophy
(really psychology) of Herbert Spencer was one of the many powerful influences
abroad, tending to divert youthful minds from the truth path of knowledge. . . .
Spencer tries to force Life into a brass bottle of his own making, but the genius
will not go into the bottle." Other philosophers wait for the guileless youth (who
is foolish enough to prefer philosophy to sport ?) with mask and rapier at the
corner of every thicket. " Croce alone has defined and allocated the activities
of the human spirit, he alone has plumbed and charted its ocean in all its depth
and breadth." This is somewhat crude. It is perfectly legitimate, in philosophy,
to express any opinion whatever, but statements of this kind should be disguised
in the recognised setting of dialectic ornamentation.

Concerning the book itself, it is not now possible to describe the system or to
compare it with those of other philosophers. The statement quoted above is
descriptive to the extent that Croce duly discusses the views of many great
philosophers and substitutes his own for theirs. We must assume that these
systems satisfy some demand of the human mind. No one has recognised the
necessity for successive metaphysical systems and their tentative nature more
clearly than Mr. Bradley. ". . . existing philosophies cannot answer this purpose.
For whether there is progress or not, at all events there is change ; and the
changed minds of each generation will require a difference in what has to satisfy
the intellect. Hence there is as much reason for new philosophy as there is
for new poetry. In each case the new production is usually much inferior to
something already in existence, and yet it answers a purpose for it appeals more
personally to the reader " {Appearance and Reality, p. 6).

To extant and recent metaphysicians, Bradley, James and the pragmatists,
Bergson, we must now add Croce. Whether or no the newcomer is likely to
satisfy the quasi-aesthetic need which calls for metaphysics, only time can show.
The reviewer is strongly opposed to the trend of that part of the argument which
asserts so absolute and impassable a gulf between a philosophy of the practical and
practical philosophy. But that fundamental we cannot discuss here.

H. S. S.

1 It is as well to state that I am not accusing Mr. Ainslie of any specific misunder-
standing of Croce. The sense of the remark is that of the proverbial definition of
metaphysics : " When a man who does not know what he is talking about addresses
a number of people who do not understand him, that is metaphysics."

i9o SCIENCE PROGRESS

Marine Engineering. By Engineer-Captain A. E. Tompkins, Royal Navy
(Retired). [Pp. ix + 812.] (London: Macmillan & Co., 1914. Price l$s.
net.)

This work is pre-eminently of a practical character, covering in a very satisfactory
manner the whole range of machinery usually coming under the care of marine
engineers.

The various organs of a ship are described, and their action explained in
clear and readable style, inspiring the reader with confidence as to the practical
acquaintance of the author with the machines he deals with.

Adequate treatment is given to the more recent developments of marine
engineering, namely, the use of the steam turbine and various types of internal
combustion engines.

The chapter on Steam Turbines is particularly well arranged, and the writer
may be, in this instance, forgiven his excursion into the history of a subject about
which, at present, very little has been written ; though there is little justification
for the introductory matter on the early development of the steam engine, or
on definitions and units, or on the elementary thermo-dynamics of heat engines,
concerning all of which there is already a wealth of able literature.

The book includes a very detailed section on the various kinds of marine
boilers, embodying much useful information on the several types of water-tube
boilers now in use in the Royal Navy.

There is a section on combustion, which brings out the great importance of
this process on the economy of working, and includes a chapter on the com-
bustion of liquid fuel, which is now becoming more and more general, especially
on the ships of the Royal Navy.

The reciprocating steam engine receives careful attention in every particular,
and all its immediate auxiliaries are given due consideration.

The chapter on indicator diagrams strikes one as being extremely useful,
developing as it does the uses of this instrument for detecting the nature of
the trouble with faulty engines.

The screw propeller is described, the author, in this case, wisely confining
himself to practical matters and common phenomena, leaving all but the very
elementary theory to more specialised works.

The auxiliary machinery, other than that employed in actual propulsion, is well
treated, so that an engineer reader has in this work a good deal of information
on the ever-increasing and varied auxiliaries which come under his charge, such
as electrical generating sets, steering gears, refrigeration plant, etc.

In conclusion, it may be said that this volume may be thoroughly recom-
mended to every marine engineer, whether he be a naval man or in the merchant
service, as a sound and readable work.

Malaria : Etiology, Pathology, Diagnosis, Prophylaxis, and Treatment, by
Graham E. Henson, M.D., with an Introduction by Prof. Charles
C. Bass, M.D. [Pp. 190 and 27 Illustrations.] (St. Louis: C. V. Mosby
Company, 19 13.)

The literature of Malaria is so very large that it is impossible to write a complete
text-book upon the subject except at great length. At the same time short text-
books are useful for medical men and sanitarians who come only occasionally into
contact with the disease ; and Dr. Henson's little work is extremely useful for this
purpose. It gives a good resume of most of the important departments of the

REVIEWS 191

subject, and discusses some of them as completely as possible within its narrow
limits. It begins with a short historical and geographical chapter, continues with
a study of the parasites and a discussion of the carrying agents, the Anopheline
mosquitoes, and describes the recent cultivation of the parasites by Bass and
Johns, recently confirmed by D. Thomson and Ziemann and others. It also
gives a good resume of the various theories regarding relapses. In this last
connection, I think that the hypothesis of intracorpuscular conjugation has been
much over-rated. As long ago as 1898, I supported Mannaberg's ideas from my
own observations in connection with the so-called Proteosojna of birds, in which
many corpuscles contained five or six small parasites which appear to coalesce
in order to produce the sexual forms. But it is very difficult to give a genuine
proof of their really doing so, while the supposed process appears to be very
contrary to what we should expect from our general biological knowledge. But
even if we admit that this conjugation does occur, it is still impossible to under-
stand how it can have any effect in continuing the species of parasites in the host.
The conjugation is supposed to produce the sexual forms, and these, for reasons
which I have frequently given, cannot be proved to be concerned in such con-
tinuation of the species — though of course they continue the species in the
mosquito. Rather an unnecessary fuss is made upon this question, because,
after all, the long continuance of the malaria parasites in the host is precisely
similar to the continuance of other organisms, and probably depends upon
immunity questions. The author gives also a short review of my analytical study
of the factors concerned in the spread of malaria in a community, though he
does not deal with my actual general epidemiological equations (given in the
second edition of my book on The Prevention of Malaria and also in Nature,
October 5, 191 1, and February 8, 1912). It is singular that though these
equations are of vital importance in the whole of epidemiology, they have received
scarcely any attention from any of the very numerous epidemiologists who instruct
us on these matters. Perhaps medical men are too little given to exact thought
to make very good epidemiologists. Their processes of reasoning are generally
more qualitative than quantitative, and their mistakes are, still more frequently,
correspondingly astonishing. Nevertheless, Dr. Henson shows more exactness
than usual, and his book does not admit of a detailed study of this subject. Much
recent work on malaria is open to a logical fallacy connected with microscopical
work which I have also ventured to point out. An observer examines a large
number of objects one after another. What he sees is often described correctly
enough ; but when he attempts to connect the different objects by means of a
mental thread which he calls a life-history, he is apt to forget that this thread
is hypothetical, and is finally tempted to imagine that it is as real as the objects
which he sees. This is an explanation of the extremely inconclusive work which
is done on the life-history of many microscopical organisms. For instance, scores
of observers have come to different conclusions regarding the life-history of various
trypanosomes, at a great expense of money and time ; and yet our knowledge
is very defective. What is wanted is new methods, especially those of cultiva-
tion and correct enumeration. As regards malaria, these new methods are already
yielding fruit, and will probably revolutionise our study of the subject very soon.
In the meantime Dr. Henson's book ought to be in the hands of all those who
require a condensed knowledge of the subject.

R. ROSS.

i 9 2 SCIENCE PROGRESS

Sanitation in India. By J. A. TURNER, M.D., D.P.H., Executive Health
Officer, Bombay Municipality, with Contributions by B. K. GOLDSMITH,
Ml'., D.P.H., S. C. HORMUSJI, L.R.C.P., M.R.C.S., M.D., D.P.H.,
K. B. SHROFF, L.M.S., D.P.H., D.T.M., and L. Godinho, L.M. & S.,
M.D., D.P.H. [Pp. viii + 1014. Illustrated.] (Bombay: The Times oj
//ul 'in, 19 1 4.)

This is a book of the same size, but is more technical in its structure. It is
dedicated to the Municipal Corporation of Bombay, and is written by the
Executive Health Officer of that great city — which is now become perhaps the
second city in the Empire. There are contributions by four able medical men.
The work begins with an outline of sanitary administration in India, and then
continues with the disposal of town refuse and sewage, water supply, food and
milk, infectious diseases and their prevention, malaria and other diseases due to
animal parasites, disinfection, dangerous trades, school hygiene, housing, and
vital statistics ; and there are specially useful chapters on habits and customs in
relation to health and on the routine work of sanitary officials. The matter
appears to be very correct as a rule, but it is unfortunate that parthenogenesis is
definitely described as being a third method of reproduction in malaria. Such
statements are examples of the way in which what were originally merely con-
jectures, even of a wild description, become gradually crystallised by the petri-
faction of time into absolute truths. Once this has happened, scarcely any amount
of criticism of the supposed truth is effective in getting it eliminated from the
text-books. The work will be a necessary part of the health officer's library,
especially now that Mr. J. A. Jones's book is out of print.

R. R.

Hygiene and Diseases of India. A Popular Handbook. By Lieut. -Col.
Patrick Hehir, I. M.S., M.D., D.P.H., D.T.M. Third Edition, Revised
and Illustrated. [Pp. ii + 1003.] (Madras: Higginbothams, Ltd., 1913.
Price 6-8 Rs.)

Colonel Hehir, a distinguished officer of the Indian Medical Service, has
written many useful works relating to the prevention of disease, medical adminis-
tration, etc. His book under review (third edition) is stated to be a popular
handbook, and should therefore be considered as such. This does not mean that
the work is not worthy to be a book of reference for medical sanitarians. It is
full of useful information ; but the necessary table of detailed contents is not
given, and the reader is obliged to rely mostly upon an index. The book is,
however, divided into three sections, namely, General Hygiene, Personal Hygiene,

and Diseases of India, and is very suitable for public instruction.

R. R.

BOOKS RECEIVED

{Publishers are requested to notify prices')

Theory of Functions of a Complex Variable. By Dr. Heinrich Burkhardt,
O. Professor, Technical School, Munich. Authorised Translation from the
Fourth German Edition, with the Addition of Figures and Exercises by
S. E. Rasor, M.Sc, Professor of Mathematics, the Ohio State University.
London : D. C. Heath & Co., 2 and 3, Portsmouth Street, Kingsway, W.C.
(Pp. xiii, 432.) Price I2.y. 6d. net.

BOOKS RECEIVED 193

Spectrum Analysis, applied to Biology and Medicine. By the late C. A.
Macmunn, M.A., M.D., Author of "The Spectroscope in Medicine," etc.,
Articles in the "Encyclopaedia Britannica " and " Quain's Dictionary of
Medicine." With a Preface by F. W. Gamble. With Illustrations. Longmans,
Green & Co., 39, Paternoster Row, London ; Fourth Avenue and 30th Street,
New York; Bombay, Calcutta, and Madras, 1914. (Pp. xiv, 112.) Price
$s. net.

I. K. Therapy, with Special Reference to Tuberculosis. By W. E. M. Arm-
strong, M.A., M.D., Dublin ; Bacteriologist to the Central London
Ophthalmic Hospital ; Late Assistant in the Inoculation Department,
St. Mary's Hospital, Paddington, W. London : H. K. Lewis, 136, Gower
Street, W.C., 1914. (Pp. x, 83.) Price 5^. net.

Interpretations and Forecasts : a Study of Survivals and Tendencies in Con-
temporary Society. By Victor Branford, M. A., sometime Honorary Secretary
of the Sociological Society. London : Duckworth & Co., 1914. (Pp. 410.)
Price 7s. 6d. net.

Bio-Philosophy, or The Meaning of Comparative Physiology, Comparative
Psychology, and Organic Evolution. By Joel N. Eno, A.M. Published
by the Author. Printed by the New Haven Printing Company, New
Haven, Conn., 1913. (Pp. 30.)

Researches into Induced Cell-Reproduction in Amoebae. By John Westray
Cropper, M.B., M.Sc, Liverpool, M.R.S.C. Eng., L.R.C.P. London,
and Aubrey Howard Drew. With Illustrations. The John Howard
McFadden Researches, vol. iv. London : John Murray, Albemarle
Street, W. April, 1914. (Pp. 112.) Price 5-r. net.

Plague and Pestilence in Literature and Art. By Raymond Crawfurd, M.A.,
M.D. Oxon., F.R.C.P., Fellow of King's College, London. Oxford : At the
Clarendon Press, 1914. (Pp. viii, 222.) Illustrated. Price 12s. 6d, net.

The Quaternary Ice Age. By W. B. Wright, of the Geological Survey of Ireland.
Macmillan & Co., Limited, St. Martin's Street, London, 1914. (Pp. xxiv,
464.) Illustrated. Price 17s. net.

Entomology, with Special Reference to its Biological and Economic Aspects.
By Justus Watson Folsom, Sc.D. (Harvard), Assistant Professor of
Entomology at the University of Illinois. Second Revised Edition with
4 Plates and 304 Text-Figures. Philadelphia : P. Blakiston's Son & Co.,
1,012, Walnut Street, 1913. (Pp. vii, 402.)

Modern Problems of Biology. Lectures Delivered at the University of Jena,
December 1912. By Charles Sedgwick Minot, LL.D. Yale, Toronto, and
St. Andrews, D.Sc. Oxford; Director of the Anatomical Laboratories,
Harvard Medical School ; Exchange Professor at the Universities of Berlin
and Jena, 1912-3. With 53 Illustrations. Philadelphia : P. Blakiston's
Son & Co., 1012, Walnut Street, 1913. (Pp. viii, 124.)

The Principles of Biology. By J. T. Hamaker, Ph.D., Professor of Biology,
Randolph-Macon Woman's College. With 267 Illustrations. Philadelphia:
P. Blakiston's Son & Co., 1012, Walnut Street, 1913. (Pp. 459.)

X Rays. An Introduction to the Study of Rontgen Rays. By G. W. C. Kaye,
B.A., D.Sc, Head of the Radium Department at the National Physical
Laboratory, Examiner in Medical Physics for the Universities of London
and Glasgow, Member of Council for the Rontgen Society. Longmans,
Green & Co., 39, Paternoster Row, London ; Fourth Avenue and 30th Street,
New York ; Bombay, Calcutta, and Madras, 1914. (Pp. xix, 252.) Price $s. net.

*N>

i 9 4 SCIENCE PROGRESS

Annual Magazine Subject-Index, 191 3. A Subject-Index to a Selected List of
American and English Periodicals and Society Publications not elsewhere
Indexed. Edited by Frederick Winthrop Faxon, A.B. (Harvard). Com-
piled with the co-operation of Librarians. Boston : The Boston Book
Company, 191 4.

Of Spiritism, i.e. Hypnotic Telepathy and Phantasms — Their Danger. By
the Hon. J. W. Harris. London : Francis Griffiths, 1913. (Pp. 126.)
Price 2s. bd.

The Simpler Natural Bases. By George Barger, M.A., D.Sc, formerly Fellow
of King's College, Cambridge ; Professor of Chemistry in the Royal
Holloway College, University of London. Longmans, Green & Co.,
39, Paternoster Row, London ; New York, Bombay, and Calcutta, 1914.
(Pp. viii, 215.) Price bs. net.

Nucleic Acids : Their Chemical Properties and Physiological Conduct. By
Walter Jones, Ph.D., Professor of Physiological Chemistry in the Johns
Hopkins Medical School. Longmans, Green & Co., 39, Paternoster Row,
London; New York, Bombay, and Calcutta, 1914. (Pp. viii, 118.) Price
$s. bd. net.

The Internal Secretory Organs : Their Physiology and Pathology. By Prof.
Dr. Artur Biedl, Vienna. With an Introductory Preface by Leonard
Williams, M.D., M.R.C.P., Physician to the French Hospital, Assistant
Physician to the Metropolitan Hospital. Translated by Linda Forster.
London : John Bale, Sons & Danielsson, Ltd., Oxford House, 83-91, Great
Titchfield Street, Oxford Street, W., 191 3. (Pp. viii, 606.) Price 21 s. net.

The Instinct of Workmanship, and the State of the Industrial Arts. By Thorstein
Veblen, Author of " The Theory of the Leisure Class." New York : The
Macmillan Company, 1914. (Pp. viii, 355.) Price bs. bd. net.

The School and College Atlas. 103 Maps, Physical, Political, and Commercial,
Index. London: G. W. Bacon & Co., Ltd., 127, Strand, W.C. ; 14, Union
Court, Old Broad Street, E.C.

Preliminary Report on the Treatment of Pulmonary Tuberculosis with Tuber-
culin. By Noel D. Bardswell, M.D., Medical Superintendent. With a
Prefatory Note by Prof. Karl Pearson, F.R.S., Director of the Galton
Laboratory of Eugenics, University of London. Presented by the Medical
Superintendent to the Council and published at the request of the Consulting
Staff. London : H. K. Lewis, 136, Gower Street, W.C, 1914. (Pp. xviii,
142.) Price bs. net.

Physiological Plant Anatomy. By Dr. G. Haberbandt, Professor in the University
of Berlin (formerly in the University of Graz). Translated from the Fourth
German Edition by Montagu Drummond, B.A., F.L.S., Lecturer in Plant
Physiology, University of Glasgow. With 291 Figures in the Text.
Macmillan & Co., .Ltd., St. Martin's Street, London, 1914. (Pp. xv, 777.)
Price 255-. net.

Kinship and Social Organisation. By W. H. R. Rivers, M.D., F.R.S., Fellow of
St. John's College, Cambridge. London : Constable & Co., Ltd., 1914.
(Pp. 96.) Price 2s. bd. net.

An Introduction to the Study of Integral Equations. By Maxime Bocher, B.A.,
Ph.D., Professor of Mathematics in Harvard University. Cambridge : at the
University Press, second edition, 1914. (Cambridge Tracts in Mathematics
and Mathematical Physics.) General Editors, J. G. Leathern, M.A., E. T.
Whittaker, M.A., F.R.S. (Pp. 71.) Price 2s. bd. net.

BOOKS RECEIVED 195

Some Minute Animal Parasites, or Unseen Foes in the Animal World. By H. B.
Fantham, D.Sc. (Lond.), B.A. (Cantab.), A.R.C.S., F.Z.S., Lecturer in
Parasitology, Liverpool School of Tropical Medicine, Formerly Assistant to
the Quick Professor of Biology, Cambridge University, and Annie Porter,
D.Sc. (Lond.), F.L.S., Beit Memorial Research Fellow, Quick Laboratory,
Cambridge. With Frontispiece and 56 Text Figures. Methuen & Co., Ltd.,
36, Essex Street, London, W.C. (Pp. xi, 319.) Price $s. net.

A Text-book of Medical Entomology. By Walter Scott Patton, M.B. (Edin.),
I. M.S., Membre Correspondant de la Societe de Pathologie Exotique, King
Institute of Preventive Medicine, Guindy, Madras ; Lately on Special Duty
for the Investigation of Kala Azar in Madras, and of Oriental Sore in Cambay
and Francis William Cragg, M.D. (Edin.), I. M.S., Fellow of the Entomo
logical Society of London, Central Research Institute, Kasauli, Punjab; Lately
Assistant to the Director, King Institute of Preventive Medicine. Christian
Literature Society for India, London, Madras, and Calcutta, 191 3. (Pp.
xxxiii, 768.)

The Open Court Company, of 149, Strand, have just ready " Problems of Science,"
by Federigo Enriques, Professor in the University of Bologna. The authorised
translation by Katherine Royce, with an introduction by Prof. Josiah Royce,
of Harvard University.

The Johns Hopkins Press, Baltimore, Maryland, U.S.A., announce that the
General Index to Vols. 21-50 of the American Chemical Journal is now ready
for delivery. Price 81.50. The index can only be had by purchase. There
have also been issued Indices to Vols. 1-10 and 11-20. Price $1.00.

INSTRUMENTS

Messrs. Prouds, Ltd., Electric Clock and Scientific Instrument Makers, 336,
Kent Street, Sydney, N.S.W., announce a New Meteorological Instrument, namely,
Murday's Thread-Recording Electrical MICRO-BAROMETER. The price of
the Micro-Barometer, as described, with two rolls of paper (one year's supply),
is £75. Extra rolls of diagram paper, 5-y. (yd. each.

Messrs. Adam Hilger, Ltd., 75A, Camden Road, London, N.W., announce
their SPECTROPHOTOMETERS for the Ultra-Violet, Visible, and Infra-Red
Regions. Prices as per catalogue.

ANNOUNCEMENTS

The Sixth International Congress of Mining, Metallurgy, Engineering, and
Economic Geology will be held in London from Monday, July 12, to Saturday,
July 15, 1915. Secretary, 28, Victoria Street, London, S.W.

The International Congress of Neurology, Psychiatry, and Psychology will be
held at Berne, Monday, 7th, to Saturday, 12th September, 1914. Secretary, Dr. L.
Schnyder, 31, Rue Monbijou, Berne, Switzerland.

196 SCIENCE PROGRESS

ANNOUNCEMENTS— continued:—

The Napier Tercentenary Celebration will be held in Edinburgh on Friday
the 24th July and following days. General Secretary, Royal Society of Edinburgh,
22 George Street.

The Morning Post, 346 Strand, London, has published a large card
giving a copious list of Congresses of Learned Societies and other bodies in
1914, 1915, etc.

Those willing to assist the Radiotelegraphic Investigation of the British
Association are requested to write to Dr. W. Eccles, University College,
London, W.C.

NOTICE

THE EMOLUMENTS OF SCIENTIFIC WORKERS

It is proposed to undertake an inquiry regarding the pay, position, tenure
of appointments, and pensions of scientific workers and teachers in this country
and the Colonies. The Editor will therefore be much obliged if all workers and
teachers who hold such appointments, temporary or permanent, paid or unpaid,
will give him the necessary information suggested below. The figures will be
published only in a collective form, and without reference to the names of
correspondents, unless they expressly wish their names to be published. The
Editor reserves the right not to publish any facts communicated to him. Workers
who are conducting unpaid private investigations must not be included. The
required information should be sent as soon as possible, and should be placed
under the following headings :

(1) Full name

(2) Date of birth. Whether married. Number of family living

(3) Qualifications, diplomas, and degrees

(4) Titles and honorary degrees

(5) Appointments held in the past

(6) Appointments now held, with actual salary, allowances, fees, and

expected rises, if any. Whether work is whole time or not

(7) Body under which appointment is held

(8) Conditions and length of tenure

(9) Pension, if any, with conditions

(10) Insurance against injury, if any, paid by employers

(11) Family pensions, if any

(12) Remarks

Printed by Hazell, Watson & Vtney, Ld., Loiidon and Aylesbury.

SCIENCE AND THE STATE:
A PROGRAMME

The action recently taken by Science Progress in calling
attention to the sweating of science in this country has
received much public attention, and many of our scientific con-
temporaries, especially Nature, have generally supported our
remarks. The Morning Post opened its columns during May
and June to a long discussion on the subject of Science and the
State; and the British Science Guild has appointed a special
committee to examine thoroughly into the matter. 1 It is a
popular complaint against men of science that they never seem
to know exactly what they want ; and we therefore now propose
to define exactly some of the steps which may be suggested for
the betterment of science in Britain and elsewhere.

Suggested Programme

(i) Improved payment of scientific workers in Universities
and other State-aided institutions, including :

(a) Adjustment of the minimum salaries of the most junior

workers ;

(b) Rises of salary depending upon length of service in

scientific or academical work ;

(d) Security of tenure and better organisation of efficiency.

(2) Special arrangements for stimulating research in Univer-
sities and other State-aided institutions, and for attracting and
retaining distinguished investigators in them.

(3) The more careful regulation of selection for appoint-
ments, especially as regards the due consideration of distinction
in research ; and the placing of professorships upon a State-
regulated standing.

(4) Abolition of the present method by which the State

1 See p. 353.
14 i97

i 9 8 SCIENCE PROGRESS

often obtains expert evidence or temporary expert assistance at
Commissions, Committees, Advisory Boards, etc., without pay-
ment or, sometimes, even the refunding of expenses.

(5) Payment of compensation by the State for proved
pecuniary losses incurred by investigators in consequence of
researches which have been unremunerative to themselves but
of admitted benefit to the public or to Government Departments.

(6) Payment of special rewards or pensions by the State to
investigators whose researches have been unremunerative to
themselves but of pecuniary advantage to Government Depart-
ments, or of general advantage to the public at large.

(7) A higher place for science in national education.

Of course this programme does not by any means include
the whole list of reforms which may be considered, but it will
suffice for immediate discussion ; and we will now proceed to
examine the items in detail.

With regard to the first item in the programme, we have
already called attention (in our last April number) to the very
bad payment of scientific teachers and investigators in our
universities — and some of the cases can be described only as
" sweating " of the worst type. Beginning at the entry of newly
graduated persons into the academic arena, we should first
point out that the system of scholarships is really utilised as a
kind of bait to induce young men into these unremunerative
paths. A scholarship of from £150 to £250 a year may seem
quite generous to a young graduate ; and he commences his
labours without thought of the future. Later on, however, he
discovers that while he has been engaged upon the researches
required by his scholarship his fellow students who were not
so easily beguiled are perhaps already thriving in the practice
of their profession, while he himself has lost time, and is
behindhand in the race. As a result of this, and because he
does not wish to waste his scientific experience, he next
generally determines to devote himself to an academic career —
with the result that he finds himself caught in the net and con-
demned for the rest of his life to the poor salary of a
demonstrator, assistant, or lecturer, with only some possible
chance of obtaining ultimately a badly paid professorship.

Regarding the actual pay of demonstrators, lecturers, and
professors, a good idea can be obtained by any one who troubles

SCIENCE AND THE STATE

i 9 g

to examine the advertisements of vacancies which appear in
scientific and technical journals — and we have already men-
tioned some figures. Dr. W. Makower has made a study of
this kind from the reports of the Board of Education for the
year 1911-12, and has published his analysis in the following
table : l

Number of
Professors.

Average

Salary of

Professors.

Number of

Lecturers and

Demonstrators.

Average
Salary.

Birmingham ....

704

195

Bristol

556

142

Newcastle

660

137

Leeds

661

3 2

164

Liverpool

853

126

Manchester

888

160

Sheffield .

710

109

Nottingham

552

118

Southampton

325

University College, Lone

on .

680

130

King's College, London

529

176

East London College

520

157

Aberystwyth .

320

Bangor .

498

107

Cardiff .

440

158

Average ....

^628

£i37

He explains that " the figures for the different institutions
are not in all cases exactly comparable since the subjects are
grouped differently in the reports from the different universities,
but they relate, as far as possible, to the ordinary science
subjects taught at the universities, and include data for mathe-
matics and engineering, but not for the medical sciences. The
figures taken from the reports include the salaries of ' part-time '
professors and lecturers, but as the figures for these are not
given separately it has been found necessary to include them in
drawing averages." We think that the average salaries are
likely in some cases to be based upon selected professorships,
and therefore to be probably much over the correct figure ; but
according to the table the average salary of a professor in
Britain is only £628 per annum, and that of lecturers and
demonstrators only £137 per annum. We hear that in one
British university, out of two hundred members of the junior

1 Morning Post, June 4, 1914.

2oo SCIENCE PROGRESS

aff in all departments (that is all members of the teaching staff
who are not full professors), not more than six receive a stipend
greater than £250 a year ! Some of the salaries given, especially
for part-time work, amount to little over £1 a week — and this,
be it remembered, often to senior persons who have spent a
large sum of money in obtaining full degrees, besides special
acquirements. It should be also remembered that rises of
salary according to length of service are seldom arranged for,
and that the pensions, if any, are extremely small and are mostly
established upon a contributory basis. The proportion of
assistants, lecturers, and demonstrators who ever become pro-
fessors is not large ; and, as a matter of fact, many of these
persons end by drifting into mercantile laboratories, or return
at a late age to the practice of various arts and professions — in
which they are at a disadvantage compared with those who
started in the same more lucrative lines of work at an
earlier age.

Regarding the British professorships themselves, we should
note that many of them are temporary or assistant professor-
ships, tenable only for a short term of years, after which the
holders may be cast loose without any donation or pension.
Even in the case of full professorships, superannuation at the
age of sixty-five, with a pension amounting to from £100 to
£200 is often insisted upon ; while in many cases the professor
must be re-elected every few years. As w 7 e have pointed out,
such scales of payment compare most unfavourably with the
emoluments of work in nearly all other professions. Thus,
Government employment is generally associated with a bonus
on retirement at an early age, and a pension on retirement at a
later one. The highest salaries and pensions in academical life
are extremely small compared with those given in military
service or the law — and the position is also comparatively
lower. In Germany, most of the professorships are held for
life, with pensions varying from 40 per cent, to 100 per cent, of
salary, according to length of service — so that an aged pro-
fessor can often retire upon his full salary when he is no longer
capable of performing the duties of his chair. Nothing like this
appears to hold in Britain, where an old man is often driven
out of his post on payment which is less than that of many an
enterprising chauffeur. We should add that cases have
occurred in which professors have been obliged to leave their

SCIENCE AND THE STATE 201

universities after fifteen or more years of service without any
pension whatever, and that without fault or disability on their
part.

Such treatment of the best educated and sometimes some of
the most valuable men in the community is a gross scandal.
It seems to be due principally to the fact that the universities
utilise additional funds which they may receive from private
subscriptions and from the Board of Education, not for con-
solidating and improving the position of their staffs, but for
starting new lectureships and professorships and for building
magnificent new structures in order to obtain reclame. In some
cases, the only persons who seem ever to enjoy increase of
salary and adequate pensions are, not the working teachers and
investigators, but the persons who hold what are called adminis-
trative posts, and who seem often to be selected according to
some extraordinary principle which ignores distinguished past
work as a recommendation.

A little while ago, during the preliminary discussions of the
Universities and Colleges with the Advisory Committee of the
Board of Education as to the possibility of establishing a
federated superannuation system, the appointment of a small
committee to discuss the details was suggested ; and this com-
mittee issued in June 1913 a " Federated Superannuation System
for Universities." But the system is really very little better
than an ordinary insurance scheme, to which the universities
do not appear to subscribe as much as they ought to do. A
member of the system can scarcely expect to obtain a pension
of more than ^"200 a year on payment of premiums amounting
to one-tenth of his income, starting at an early age, and the
pensions do not appear to be guaranteed in any way by the
State or by the universities themselves.

It seems to us that the proper way to obtain reform regarding
the whole of item 1 of the programme is for the Board of
Education to insist, as a condition of their grants to the
universities and other State-aided institutions, that such bodies
shall consider it to be one of the first charges upon their income
to make provision for adequate rises of salary and pension on
retirement for all members of their staff. Such action will check
the waste of funds just complained of upon buildings and un-
necessary new ventures, and will set the pace for all institutions
employing scientific workers. We should remember that many

202 SCIENCE PROGRESS

of the British universities are managed by business men, who
adopt commercial methods for making as big a show as possible
out of their receipts, and succeed in this chiefly by sweating
their scientific and learned employees in the manner described \
and we may add in passing that any reform in this respect
should include a very strict reform as to the persons who are
allowed to obtain positions upon the councils of these universities,
and who at present are frequently men who have not even
benefited their institutions by considerable pecuniary grants,
much less distinguished themselves by any achievements in
science and art.

Regarding the very difficult subject of security of tenure —
i (d) of the programme — we had better merely remark at present
that it implies an adjustment between two different interests,
namely that of the university or institution and that of the
individual. It is certainly the case that many individuals who
find themselves in too secure a position thereupon cease to do
good work; but, on the other hand, the absence of security
tends to impair the working efficiency of the individual. Pro-
bably the best way is to retain more power for the discharge
of members of the staff on condition that such power can be
exercised only on compensation by means of a bonus or pension
graduated according to length of past service. Thus a university
should be able to insist upon superannuation in consequence of
failure of powers at any given age, but should not be allowed
to do so without giving suitable compensation as defined.

Another principle should be held in mind. Most teachers
and workers at the universities are at present often obliged
to shift from one institution to another, because, in fact,
academical life is becoming a kind of general public service.
At present such shifts frequently imply a loss of seniority ; and
arrangements should be made to avoid this. Indeed, the
Federated Superannuation System for Universities just referred
to has already considered the point ; and the question arises
whether the whole of the academical profession should not be
converted into a Government service, or at least into a service
which is very carefully controlled by Government. Until
something like this is done, cases of exploitation or hardship
are likely to continue.

Prof. Soddy has suggested a scheme, well worthy of attention,
for directly stimulating research in university departments by

SCIENCE AND THE STATE 203

increasing the grants for each department pro rata according
to the research work done in them. There are of course diffi-
culties to be met, but these are probably not insuperable; and
something of the nature should be considered at an early date.
We are all of us familiar with certain departments in which no
research at all is done, and also, fortunately, with those which
distinguish themselves greatly by it ; and it is not fair that
payment should be on the same scale in both. Of course, in
many departments research is not obligatory at all ; and we
would suggest that where it is made obligatory it should
certainly be specially paid for in addition to the payments made
for teaching by itself. Otherwise such proposals will merely
result in further sweating.

The suggestion under heading 3 of the programme is a
difficult but weighty one. It can properly be met only by
attention to the suggestions already made regarding State-
supervision of the universities. In most countries on the con-
tinent of Europe a professor is an important person, because
he is supposed to possess the most detailed knowledge possible
of his subject. In Britain and America, however, a university
professor appears to be ranked with "professors" of boxing and
dancing, and to be looked upon with some indulgent contempt.
At the same time, little care is exercised with us in the selection
of men for these posts— which are often given to local candidates
of not much account, or to any person who possesses the savoir
faire to apply himself to the proper persons. The wh'ole system
of election is faulty — as was well pointed out in a paper pub-
lished some years ago in the University Review. At present
vacancies are generally advertised in the press, and applicants
are told to send in testimonials, however important the post
may be. Thus a number of applicants are kept on tenterhooks
of doubt for months, and are also obliged to tout amongst
eminent men for testimonials, and to go to the expense of
printing them afterwards. As only one of the candidates obtains
the coveted post, this amounts to quite a serious infliction ; and
it is time that the system is changed for appointment by invita-
tion, supervised by some censorship by, say, the Board of
Education. Indeed, we think that the whole status of the
professor should be raised by placing every professorship upon
something like a regius standing, with a selection ultimately
approved by Government, and fixity of tenure guarded by a