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1

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1

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6

P I A S. h 3

A HALF-CENTURY OF SCIENCE.

BvT. H. HUXLEY, F. R. S.

AND GRANT ALLEN.

I. THE ADVANCE OF SCIENCE
IN THE LAST HALF CENT-
URY.

BY T. H. HUXLEY. F.R.S.

The most obvious and the most db-
tinclive features of the history of
civilization, during the last fifty years,
is the wonderful increase of industrial
production by the application of ma-
chinery, the improve'.nent of old tech-
nical processes and the invention of
new ones, accompanied by an even
more remarkable development of old
and new means of locomotion and in-
tercommunication. By ihis rapid and
vast multiplication of the commodities
and conveniences of existence, the
general standard of comfort has been
raised ; the ravages of pestilence and
famine have been checked; and the
natural obstacles, which time and
space offer to mutual intercourse, have
been reduced in a manner and to an
extent, unknown to former ages. Tlie
duninution or removal of local igno-
rance and prejudice, the creation of
common interests among the most
widely separated peoples, and the
strengthening of the forces of the
organization of the commonwealth
.igainst those of political or social
anarchy, thus effected, have exerted
an influence on the present and
future fortunes of mankind the full
significance of which may be divined,
b'.!t cannot, as yet, be estimated at its
f ill value.

This revolution — for it is nothing

less — in the political and social as-
pects of modern civilization has been
preceded, accompanied, and in great
measure caused, by a less obvious, but
no less marvelous, increase of^ natural
knowledge, and especially of that part
of it which is known as physical
science, in consequence of the appli-
cation of scientific method to the inves-
tigation of the phenomena of the ma-
terial world. Not that the growth of
physical science is an exclusive prerog-
ative of the Victorian age. Its present
strength and volume merely indicate
the highest level of a stream which
took its rise, alongside of the primal
founts of philosophy, literature, and
art, in ancient Greece ; and, after
being dammed up for a thousand years,
once more began to flow three cent-
uries ago.

It may be doubted if even-handed
justice, as free from fulsome panegy-
ric as from captious depreciation,, has
ever yet been dealt out to the sages of
antiquity who, for eight centuries,
from the time of Thales to that of
Galen, toiled at the foundations of
])hysical science. But, without enter-
ing into the discussion of that large
question, it is certain that the labors
of these early workers in the field of
natural knowledge were brought to a
standstill by the decay and disruption
of the Roman Empire, the consequent
disorganization of society, and the
diversion of men's thoughts from sub-
lunary matters to the problems of
the supernatural world suggested by
Christii^n dogma in the Middle Ages.

I

' '^56^5

THE ADVANCE OF SCIENCE

And, notwithstanding sporadic at-
tempts to recall men to the investiga-
tion of nature, here and there, it was
not until the fifteenth and sixteenth
centuries that physical science made
a new start, founding itself, at first,

with Kepler's great additions ; the
astronomical discoveries and the phy-
sical investigations of Galileo; the
mechanics of Stevinus and the " De
Magnete " of Gilbert ; the anatomy
of the great French and Italian

altogether upon that which had been I schools and the physiology of Harvey.

done bv the Greeks. Indeed, it must j In Italy, which had succeeded Gieece

in the hegemony of the scieniitic
world, the Accademia dei Lyncei and

be admitted that the men of the Re
naissance, though standmg on the

philosophers,
ihey saw as
much as their forerunners had done.

shoulders of

the

old

were a long time before

sundry other such associations for the
investigation of nature, the models of
all subsequent academies and scientific

The first serious attempts to carry' societies, had been founded while the
further the unfinished work of Archi- j literary skill and biting wit of Galileo
medes, llipparchus, and Ptolemy, of : had made the great scientiiic ques-

Aristoile and of

enough

arose among the

Galen, naturally i
astronomers
and the physicians. For the impen- '
ous necessity of seeking some remedy
for the physical ills of life had in-
sured the preservation of more or less
of the wisdom of Hippocrates and his
successors ; and, by a happy conjunc-

intelligible,
pub-

general

tions of the day not only
but attractive, to the
lie.

In our own country, Francis Bacon
had essayed to sum up the past of
physical science, and to indicate the
path which it must follow if its great
destmies were to be fuifilletl. And

tion of circumstances, the Jewish and 1 though the attempt was just such a
the Arabian physicians and philoso- : magnificent failure as might have been
l)hers escaped many of the influences j expected from a man of great endow-
which, at that time, blighted natural ments, who was so singularly devoid
knowledge in the Christian world, j of scientific insight that he could not
On the other hand, the superstitious ; undtTstand the value of the work
hopes and tears which afToided conn- already achieved by the true instaur-
tenance to astrology and to alchemy ators of physical science ; yet the
also sheltered astronomy and the majestic eloquence and the fervid
germs of chemistry. Whether for this, vaticinations of one who was con

or for some better reason, the found-
ers of the schools of the Middle Ages
included astronomy, along with geome-
try, arithmetic, and music, as one of
the four branches of advanced educa-
tion ; and, in this respect, it is only
just to them to observe that they
were far in advance of those who sit
in their seats. The school-men con-
sidered no one to be properly educated
unless he were acquainted with, at
any rate, one branch of physical sci-
ence. We have not, even yet, reached
that stage of enlightenment.

In the early decades of the seven-
teenth century, the men of the Re-
naissance could show that they had al-
ready put out to good interest the
treasure bequeathed to them by the
Greeks. They had produced the as-
tronomical system of Copernicus,

spicuous alike by the greatness of his
rise and the depth of his fall, drew
the attention of .all the world to the
" new birth of Time."

But it is not easy to discover satis-
factory evidence that the " Novum
Organum"had any direct beneficial
influence on the advancement of nat-
ural knowledge. No delusion is
greater than the notion that method
and industry can make up for lack of
motherwit, either in science or in
practical life ; and it is strange that,
with his knowledge of mankind, Bacon
should have dreamed that his, or any
other, " via inveniendi scientias"
would " level men's wits " and leave
little scope for that inborn capacity
which is called genius. As a matter
of fact, Bacon's "via" has proved
hopelessly impracticable ; while the

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kn

IN THE LAST HALl-CENTURY.

my
las"

"anticipation of nature" by the in
vcn'i Ml of hypotheses based on in

Bacon or Ilobbes, Rend Descartes,
not only in his immortal " JiiscGurs

conriictc inriiictions, whicli he spe- de la Methode " and elsewhere, went
cially c< lulennis, has j^rovcd itself to down to the foundations of scientific
be a most crticient, indeed an indis- certainty, bur, in his '* Principes de
pensa))le, instnnnent of scientific Philosophie," indicated where the
pro:;ress. l-'inally, tliat transceiuien- : fjoal of physical science really lay.
tal rili'lu-my — the siipeiiii<liiceinent of [ However, 1 )Lfscartes was an eminent
new forms on matter — wliicii llacon ' mathematician, and it would seem
dt'cIaiL's to be tlie supreme aim of ' that the bent of his mind letl him to
scieiKc, has been whojiv i_:;nored by i overestimate the value of deductive

reasoiiiiii; from general ])rinciples, as
much as iJacoii had underestimated
it. Tlie pro};ress of physieal science

those who have created the physical
kno'.vle<l;;e of the present day.

Kven the eloquent advocacy of the
Chanrellor broii<:;ht no unmixed good has been effected neither by Haconians
to physical science. It was natural iior by Cartesians, as sueli, but by
enougli tliat the man who, in his bet- , men like (lalileo and Harvi-y, Hoyle
ter moments, took "all knowledge ' and Newton, who would have done
for his patrimony," but, in his worse, ; their work just as well if neiliier 15a-
sold tiiat bir'.iiright for tlie mess of : con nor Descartes had ever pro-
pottage of court favor and pro- 'pounded their views respecting the
fessional success, for pomp and shosv, manner in which scientific nivestiga-
shoulcl be led to attach an undue lion should bo ])ursue(l.
value to the practical advantages The progress of science, durin*;
which he foresaw, as Roger 1}. icon I the first century aft<!r Ikicon's death,
and, indeed, Seneca had foreseen, j by no means veritied his sanguine
long before his time, must follow in ' prediction of the fruits which it would
the train of the advancement of nat- 1 yield. For, though the revived and
uial knowledge. The burden of I?a- j renewed study of nature had spread
con's pleadings for science is the i and grown to an extent which sur-

passed reasonable expectation, the
practical results — the "good to men's
estate " — weie, at tlrst, by no means
apparent. Sixty years after Bacon's
death, Newton had crowned the long
labors of the astronomers and the
physicists, by co-ordinating the i)Iie-

gathering of fruit " — the importance
of winning solid material advantages
bv the investigation of nature and
the desirableness of limiting the ap-
plication of scientific methods of in-
(juiry to that field.

Bacon's younger contemporary,
Hobbes, casting aside the prudent nomena of molar motion throughout
reserve of his predecessor in regard the visible universe into one vast sys-
to those matters about which the tem ; but the " Princi!)ia " helped no
Oown or the Church might have . man to either wealth or comfort,
something to say, extended scientific , Descartes, Newton, and Leibnitz had
methods of inquiry to the phenomena : opened up new worlds to the ma'lie-
of mind and the |.iroblems of social I matician, but the acriuisitious of their
organization; while, at the same [genius enriched only man's ideal
time, he indicated the bounflary be- 1 estate. Descartes had laid the foun-
iween the province of real, and that dations of rational cosmogony and of
of imaginary, knowledf"". The i physiological psychology ; Boyle had
" Principles of Philosophy ' and the i proilucetl models of experimentation

" Leviathan " embody .'i coherent sys-
tem of purely scientific thought in
language which is a model of clear
and vigorous English style. At the
same time, in France, a man of far
greater scientific capacity than either

in various branches of physics and
chemistry; Pascal and Torricelli had
weighed the air ; Malpighi and Grew,
Ray and Willoughby had done work
of no less importance in the biologi-
cal sciences ; but weaving and spin-

Tin: AnvANCH or science

n'lng were carried on with the old ap-

Cliaiiccs ; nobody could travel faster
y sea or by land than at any previous
time in the world's history, and King
(leorge could send a message from
London to York no faster tiian King
John nught have done. Metals were
worked from their ores by immemo-
rial rule of thumb, and the center of
the iron trade of these islands was
still among the oak forests of Sussex.
The utmost skill of our mechanicians
did not get beyond the production of
a coarse watch.

The middle of the eighteenth cent-
ury is illustrated by a host of great
names in science — English, French,
German, and Italian — especially in

subservient to their wants, and which
would disappear if man's shaping >ind
guiding hand were withdrawn. Kvery
mechanical artifice, every chemically
pure substance employed in manu-
facture, every abnormally fertile race
of plants, or rapidly growing and fat-
tening breed of animals, is a part of
the new nature created by science.
Without it, the most densely popula-
ted regions of modern Europe and
America must retain their primitive,
sparsely inhabited, agricultural or
pastoral condition , it is the founda-
tion of our wealth and the condition
of our safety from submergence by
another flood of barbarous hordes ; it
is the bond which unites into a solid

the fields of chemistry, geology, and | political whole, regions larger than
biology ; but this deepening and
broadening of natural knowledge pro
duced next to no immediate prac-
tical benefits. Even if, at this time,
Francis Uacon could have returned
to the scene of his greatness and of i luxuries, but conduce to physical and
his littleness, he must have regarded | moral well-being. During the last
the philosophic world which praised i fifty years, this new birth of time,

any empire of antiquity ; it secures
us from the recurrence of the pesti-
lences and famines of former times ;
it is the source of endless comforts
and conveniences, which are not mere

this new nature begotten by science
upon fact, has pressed itself daily

and disregarded his precepts with
great disfavor. If ghosts are consist-
ent, he would have said, "These land hourly upon our attention, and
people are all wasting their time, just } has worked miracles which have mod-
as Gilbert and Kepler and Galileo , ified the whole fashion of our lives,
and my worthy jihysician Harvey did | What wonder, then, if these aston-
ii> my day, VVhere are the fruits of i ishing fruits of the tree of knowledge
the restoration of science which 1 1 are too often regarded by both friends
promised? This accumulation of ' and enemies as the be-all and end-all

bare knowledge is all very well, but
cui bono I Not one of these people
is doing what I told him specially to
do, and seeking that secret of the
cause of fotms which will enable men
to deal, at will, with matter, and su-
perinduce new natures upon the old
foundations."

l>ut, a little later, that growth of
knowledge beyond imaginable utili-
tarian ends, which is the Condition
precedent of its practical utility, be-
gan to produce some effect upon prac-
tical life ; and the operation of that
part of nature we call human upon
the rest began to create, not "'new
natures," in Bacon's sense, but a new.
nature, the existence of which is de-
pendent upon men's efTorts, which is

of science ? What wonder if some
eulc)gize, and others revile, the new
philosophy for its utilitarian ends and
its merely material triumphs.^

In truth, the new philosophy de-
serves neither the praise of its eulo-
gists, nor the blame of its slanderers.
As I have pointed out, its disciples
were guided by no search after prac-
tical fruits, during the great period of
its growth, and it reached adolescence
without being stimulated by any re-
wards of that nature. The bare enu-
meration of the names of the men
who were the great lights of science
in the latter part of the eighteenth
and the first decade of the nineteenth
century, of Herschel, of Laplace, of
Young, of Fresnel, of Oersted, of Cav-

IN THE LAST HALF-CENTURY.

5

riends
end-all
some
le new
ids and

by de-
5 eulo-
derers.
isciples
r prac-
eriod of
escence
any re-
are enii-
ie men
science
hteenlU
leteenth
lace, of
of Cav-

endish, of Lavoisier, of Davy, of La-
marck, of Cuvier, of Jussieu, of De-
candoUe, of Werner and of Hntion,
suffices to indicate the strength of
physical science in the aj;e immedi-
ately preceding that of which I have
to treat. But of which of these gr^at
men can it be said that their labors
were directed to practical ends ? I
do not call to mind even an invention
of practical utility which we owe to
any of them, except the safety lamp
of Davy. Werner certainly paid at-
tention to mining, and I have not for-
gotten James Watt. But, though
some of the most important of the
improvements by which Watt con-
verted the steam-engine, invented
long before his time, into the obedi-
ent slave of man, were suggested and
guided by his acquaintance with sci-
entific principles, his skill as a prac-
tical mechanician, and the efficiency
of Bolton's workmen had quite as
much to do with the realization of his
projects.

In fact, the history of physical
science teaches (^and we cannot loo
carefully take the lesson to heart)
tliat the practical advantages, attain-
able through its agency, never have
been, and never will be, sufficiently
attractive to men inspired by the in-
born genius of the interpreter of na-
ture, to give them courage to under-
go the toils and make the sacrifices
which that calling requires from its
votaries. That which stirs their
puLses is the love of knowledge and
tile joy of the discovery of the causes
of things sung by the old poets — the
supreme delight of extending the
realm of law and order ever farther
towards the unattainable goals of the
infinitely great and the infinitely
small, between which our little race
of life is run. In the course of this
work, the physical philosopher, some-
times intentionally, much more often
unintentionally, lights upon some-
thing which proves to be of practical
value. Great is - the rejoicing of
those who are benefited thereby ;
and, for the moment, science is the
Diana of all the craftsmen. But,

I even while the cries of jubilation re- ,
sound and this floatsam and jetsam ,
: of the tide of investigation is being
turned into the wages of workmen
and the wealth of capitalists, the crest
; of the wave of scientilic investigation
is far away on its course over tlic il-
^ limitable ocean of the unknown.
j Far be it fiom me to depreciate the
I value of the gifts of science to practi-
cal life, or to cast a doubt upon the
' propriety of the course of action of
1 those who follow science i*n the hope
j of finding wealth alongside truth, or
, even wealth alone. Such a profes-
sion is as respectable as any other,
j And quite as little do I desire to ig-
nore the fact that, if industry owes a
[ heavy debt to science, it has largely
I repaid the loan by the important aid
: which it has, in its turn, rendered to
the advancement of science. In con-
'sidering the causes which hindered
; the progress of physical knowledge
in the schools of Athens and of Alex-
landria, it has often struck me * that
where the Greeks did wonders was
in just those branches of science,
such as geometry, astronomy, and
anatomy, which are susceptible of
^ very considerable development with-
out any, or any but the simplest, ap-
: pliances. It is a curious speculation
j to think what would have become of
j modern physical science if glass and
I alcohol had not been easily obtain-
able , and if the gradual perfection
{ of mechanical skill for industrial ends
had not enabled investigators to ob-
tain, at comparatively little cost,
I microsco|)es, telescopes, and all tiic
exquisitely delicate apparatus for de-
I terminiiig weight and measure and
for estimating the lapse of lime with
exactness, which they now command.
If science has rendered the colossal
development of modern industry pos-
: sible, beyond a doubt industry has
i done no less for modern physics and
] chemistry, and for a great deal of

• There are excellent remarks to the same
effect in Zeller's Philosophic Jer Griechtn,
'I'heil n. Abth. ii. p. 407, and in Kncken's
Die Methode der Arislotelischen Forschiinf^,
[jp. 1 38 et seq.

THE ADVANCE OF SCIENCE

modern biology. And as the cap- 1 science has ever been done by men,
tains of indiisliy have, at last, begun whatever their powers, in whom the
to be aware that the condition of divine afllatus of the triithstei<er was

snccess in that warfare, under the
forms of peace, which is Ivnown as
industrial competition Hes in the dis-

wanting. Men of moderate capacity
have done great things because it
animated tiiem ; aiifl men of great

ciplineof tlie troops and the use of | natural gifts have failed, aijsolutely
arms of precision, just as much as it or relatively, because they lacked

does in the warfare which is called
war, their demand for that discipline,
which is technical education, is re
u|)on science in a manner

acting

this one thing needful.

To anyone who knows the business
of investigation practically, liacon's
notion of establishing a comjiany of
which will, assuredly, stimulate its' investigators to work for " fruits," as
future growth to an incalculable ex- if the pursuit of knowledge were a
tent. It has become obvious that kind of mining operation and only
the interests of science and of in ! required well-directed picks and
dustry are identical, that science ] shovels, seenis very strange. f In
cannot make a step forward without, ■ science, as in art, and, as I believe,
sooner or later, opening up new chan- 1 in every other sjjhere of human activ-

ncls for industry ; and, on the other
hand, that every advance of industry

itv, there mav be v/isdom in a nnilti-
tude of counsellors, but it is only in

facilitates those experimental investi- - one or two of them. And, in scien-
gations, upon which the growth of | tilic inquiry, at any rate, it is to that
science depends. AVe may hope one or two that we must look for
that, at last, the weary misunder- ; light and guidance. Newton said
standing between the practical men j that he made his discoveries by " in-
who professed to despise science, and I tending" his mind on the sul^ject ;
the liigh and dry philosophers who j no doubt truly. Hut to equal his suc-
professed to despise practical results, i cess one must have the mind which
is at an end. | he " intended." Forty lesser men

Nevertheless, that which is true of | might have intended their minds till
the infancy of physical science in the i they cracked, without any like result.
Greek world, that which is true of its! It would be idle either to affirm or
adolescence in the seventeenth and to deny that the last half-century has
eighteenth centuries, remains true of ' produced men of science of the ( ali-
its riper age in these latter days of bre of Newton. It is sufficient that

the nineteenth century. The great

steps in its progress have been made, " For a long time that sensiliility, or that
are made, and will be made, bv men vanitv, which people call love of glory is
who seek knowledge simply because much blunted in me. I labor much less to
" ' ■' catch the suffrapcs of the public than to

obtain an inward ajiproval which has always
been the mental reward of mv efforts. With-

they crave for it. They have their
weaknesses, their follies, their vani
ties, and their rivalries, like the rest

out doubt I have often wanted the spur of

of the world ; but whatever by-ends y^^'ty »" "^ite me to pursue my researches
, '. ,. . 1 • 1 : in moments of disgust and discouragement.

may mar their dignity and impede ; ,j„j .^„ j,,^. eompliments which I have re-

their usefulness, this chief end re- ccived from MM. Ar.-igo, De Laplace, or
deems them.* Nothing great in Hiot, never gave me so much pleasure as

the discovery of a theoretical truth or the

• " ~~ confirmation of a calculation by r.xperi-

* Fresnel, after a brilliant career of dis- ' ment."
covery in some of the most difficult regions'; t " Memor.ible exemple de j'impuissance
of physico-mathematical science, died at ', des recherches collectives appliquees i la
thirty-nine veais of .ige. The following pas- deco'jvertc dcs verites nouvelles ! " savs one
sage of a letter from him to Vuung (written of the most distinguished of living French
in November 1824), (jiiotcd bv Whewcll, so s.rT\nif.t. n( the coriiorate chemical work of
aptly illustrates the sjiirit which animates the old Academie dcs Sciences. (See IJer-
the scientific inquirer that I may cite it : i thelot, Science ct PhilosoJ'hi(, p. 201.)

IN THE LAST HALF-CKNTUKV.

said

or tliat
glory is
h less to
than to
s always
. With-
e spur of
.■searches
agciiKMil.
have re-
place, or
asure as
» or the
experi-

missance
lees 5i la
savs one
Ig I'"reiuh

work of
ISee licr-

it can show a few capacities of the
first rank, competent not only to deal
profiiaijiy with the inheritance be-
qiu-alhed by their scientific fore-
fatiiers, but to pass on to their succes-
sors physical truths of a hi;j;hcr order
than any yet readied by the human
race. And if they have succeeded as
Newton succeeded, it is because they
Iiave sou'^iu truth as he soujjlit it,
with no other object than the finding
it.

I am conscious tliat in undertaking;
to jjive even the briefest sketch ot
tile pro<;ress of jihysical science, in
all its branches, (hirinj; the last half-
century, I may be thought to have
exhibited more courage than discre-
tion, and perhaps more presrunption
than either. So far as physical
science is concerned, the days of
Admirable Crichtons have long been
over, and the most indefatigalile of
hard workers may think he h is done
Wfll if he has mastered one of its
minor subdivisions. Nevertheless, it
is possible for anyone, who has fa-
miliarized himself with the operations
of science in one department, to com-
prehend the significance, and even to
form a general estimate of the value,
of the achievements of specialists in
other departments.

Nor is there any lack either of guid-
ance, or of aids to ignorance, Hy a
happy chance, the first ediiion of
Whewell's " Historv of the Inductive
Sciences" was published in 1837, and
it affords a very useful view of the
state of things at the commencement
of the Victorian epoch. As to sub-
sequent events, there are numerous
excellent summaries of the progress
of various branches of science, es-
pecially up to 1881, which was the
jubilee year of the British Associa-
tion.* And, with respect to the bi-
ological sciences, with some parts of

• I am jiarticularly indebted to mv friend
and colleague I'rofcssor Kiickcr, K. U.S., for
the many aiiite criticisms and siii.'t;<..stions
«)n my remarks respectin^i the idtiniiitf prob-
lems of ]ihysics. with which he has favored
nic, and by which 1 have greatly profited.

which my studies have familiarized
me, my personal experience nearly
coincides with the preceding half-
century. 1 may hope, therefore, that
my chance of esca|)ing serious errors
is as gr)od as that of anyone else, who
might have been persuadfd to under-
take the somewhat pfrilous enterprise
m wliii'h I find invstdf engaged.

There is yet another pn-fatory
remark which it seems desirable I
should make. It is that I think it
proper to confine myself to the work
done, without saying anvihing about
the doers of it. Meddling wiili t|iu;s-
tiuns of merit and priority is a iliornv
business at the liest of times, an«l
unless in case of necessity, altogether
undesirable when one is dealing wiih
contemporaries. No such nccis^ity
lies upon ine ; and I shall, llierefore,
mention no names of living men. lest,
perchance, I should incur tht; reproof
which the Israelites, who struggled
with one another in the tlcld, ad-
dressed to Moses--" Who m.rde thee
a prince and a judge over us.''''

Physical science is one and indivis-
ible. Althoiii;h, for practic.il pur-
poses, it is convenient to mark it out
into the primary regions of physics,
chemistry, and biologv. and to sub-
divide these into suliordinaie prov-
inces, yet the method of investigation
and tin: ultimate object of the phys-
ical inquirer are everywhere the same.

'The object is the discovery of the
rational order which pervades the
universe ; the method consists of
observation and experiment (which is
observation under artificial condi-
tions) for the determination of the
facts of nature , of indiutive and de-
ductive reasoning for the fliscovery
of their mutual relations and connec-
tion. The various bratiches of plivsi-
cal science differ in the extent to
which, at any given moment of their
history, observation on the one hand,
or ratiocination on the other, is their
more obvious feature, but in no other
way; and nothitig can be more in-
correct than the assninplion one
sometimes meets with, that physics

THE ADVANCE OF SCIENCE

has one method, chemistry another,
and biology a third.

All physical science starts from
certain postulates. One of them is
the objective existence of a m.lterial
world. It is assumed that the phe-

Physical science therefore rests on
verified or uncontradicted hypotheses;
and, such being the case, ir is not
surprising that a great condition of
its progress has been the invention of
veritable hypotheses. It is a favorite

nomena which are comprehended popular delusion that the scientilic
under this name h;ive a "substratum " | incpiirer is imder a sort of moral ob-
of *.'Xlended, in»penetrable, mobile ; ligation to abstain from going beyond
substance, which exhibits the (lualiiy i that generalization of observed facts
known as inertia, and is termed mat- 1 whici' is absurdly called " Haconian"
ter.* Another postulate is the uni- ; induction. Hut any one who is prac-
versality of the lasvof causation ; that , tically acquainted with scientific work
nothing iiappens without a cause (that i is aware that those who refuse to go

is, a necessary precedent condition),
and that the stale of the physical uni-
terse, ot any given monient, is the
consequence of its state at any pre-

beyond fact, rarely get as far as fact ;
and anyone who has studied the his-
tory of science knows that almost
every great step therein has been
.Another is that any! made by the "anticipation of nature,"
of the rules, or so-called "laws of that is, by the invention of hypotheses,
nature," by which the relation of phe- which, though veritable, often ha(I
nomena is truly defined, is true for all very little foundation to start with ;
time. The validity of these postu- i and, not unfrequently, in spite of a

Ceding monient

long career of usefulness, turned out
to be wholly erroneous in the long
run.

The geocentric system of astron-
omy, with its eccentrics and its epicy-
cles, was an hypothesis utterly at

lates is a problem of metaphysics ;

they are neither self-evident nor are

they, strictly Speaking, flemonstrablc.

The jnstilkaiion of their em|)loyment,

as axioms of physical phiiosophy, lies

in the circumstance that expectations

logically based upon them are veri ' variance with fact, which neverthe-

fied, or, at any rate, not contradicted, I less did great things for the advance-
ment of astronomical knowledge.
Kepler was the wildest of guessers.
Newton's corpuscular theory of light
was of much temporary use in optics,
though nobodv now believes in it;

challciH'.e.I. It nuy be said, for example, | j^,„i t|,e tmdulatory iheorv, which has

mat. oil the livpothesi-* of lioscoviLh, matter i j i .1 '1 .1

has no extension. ».ci..R reduced to n.athe- ^"If'^'^'^*^'-'^' ^'^f corpuscular theory

and has proved one of the most fer-
tile of instruments of research, is

whenever they can be tested by ex-
perience.

• 1 am .iware that this prnjiosition mav be

niatical points serving as centers of "forces.'

lint as the "forces" of the various centers ! tile of instruments

are conceived to limit one .inolhei's action I jj^^ed on the h\ pothesis of the exist-

m such a manner that an area around cacli 1 r i^ .» »i .u ..• r

center has .in individnalitv of >ts own. exten- ence of an "ether, the properties of

siun comes back in the 'orm of that area.
Again, a very eminent mathematician and
])itysicist — the late Ckrk Maxwell — has de-
clared that impenetrability is not essential to
our notions of matter, and that two atoms
m.iy conceivably occui)y ^^'^ same space. I
am loth to dispute any dictum of a philos-
opher as remarkable for the subtlety of his
intellect as for his vast knowledge ; but the
assertion that one and the same point or area
of space can have different (conceivably op-
posite) attributes appears to me to violate
the principle of contradiction, which is the
foundation not only of i>hysical science, but
of logic in general. It means that A can be
not-A.

which are defined m propositions,
some of which, to ordinary appre-
hension, seem physical antinomies.

It sounds paradoxical to .say that
the attainment of scientific truth has
been effected, to a great extent, by
the help of scientific errors. liut the
subject-matter of physical science is
furnished by observation, which can-
not extend beyond the limits of our
faculties; while, even within those
limits, we cannot be certain that any
^^'ervation is absolutely exact and

IN THE LAST IIALF-CENTURY.

astron-
i epicy-
ily at
vertlie-
vaiice-
ledge,
lessers.
light
optics,
in it ;
ch has
theory
ost fer-
rch, is
e exist-
rties of
sitions,
appre-
lies.
ay that
th has
;nt, by
iut the
nee is
h can-
of our
those
at any
t and

exhaustive. Hence it follows that
any given generalization from ob-
servation may be true, within the lim-
its of our powers of observation at a
given time, and yet turn out to be un-
true, when those powers of observa-
tion are directly or indirectly en-
larged. Or, to put the matter u\ an-
other way, a doctrine which is untrue
absohiiely, may, to a very great ex-
tent, be susceptible of an interpreta-
tion in accordance with the truth.
At a certain period in the history of
astronomical science, the assumption
that the planets move in circles was
true enough to serve the purpose of
correlating such observalions as were
then possil)le ; after Kepler, the as-
sumption that they move in ellipses
became true enough in regard to the
state of observational astronomy at
that time. We say still that the or-
bits of the planets are ellipses, be-
cause, for all ordinary purposes, that
is a sufficiently near approximation to
the trutii; but, as a matter of fact,
the center of gravity of a planet de-
scribes neither an ellipse or any other
simple curve, but an imntensely com-
plicated undidaling line. It may
fairly be doubted whether any gen-
eralization, or hypothesis, based upon
physical data is absolutely true, in
the sense that a mathematical proposi-
tion is so; but, if its errors can be-
come apparent only outside the limits
of practicable observation, it may be
just as usefully adopted for one of the
symbols of that algebra by which we
interpret nature, as if it were abso-
lutely true.

The development of every branch
of physical knowledge presents three
st.tges which, in their logical relation,
are s-'ccessive. The first is the de-
termination of the sensible character
and order of the phenomena. This
is Natural History^ in the original
sense of the term, and here nothing
but observation and experiment avail
us. The second is the determination
of the constant relations of the phe-
nomena thus defined, and their ex-
pression in rules or laws. The third
is the explication of these particular

laws by deduction from »lie most gen-
eral laws of matter and motion. The
last two stages constitute Natural
Philosophy in its original sense. In
this region, the invention of verifiable
hypotheses, is not only permissible,
but is one of the conditions of prog-
ress.

Historically, no branch of science
has followed this order of growth ;
but, from the dawn of exact knowl-
I edge to the present day, observation,
I experiment, and speculation have
I gone hand in hand; and, whenever
I science has halted or strayed from
I the right path, it has been, either be-
[ cause its votaries have been content
I with mere unverified or unverifiable
speculation (and this is the common-
jest case, because observation and ex-
, periment are hard work, while spec-
I ulalion is amusing); or it has been,
I because the accunuilation "of details
j of observation has for a time excluded
speculation.

'J'he progress of physical science,
since the revival of learning, is largely
due to the fact that men have giad-
ually learned to lay aside the con-
sideration of unverifiable hyjwtheses ;
to guide observation and experiment
by verifiable hypotheses; and to con-
sider the latter, not as ideal truths,
the real entities of an intelligible
world behind phenomena, but as a
symbolical langu.nge, by the aid of
which nature can be interpreted in
terms apprehensible by our intellects.
And if physical science, during the
last fifty years, has attained dimen-
sions beyond all former piecedent,
and can exhibit acliievements of
, greater importance than any former
J such period can show, it is because
' able men, animated by the true scien-
I tific spirit, carefully trained in the
I method of science, and having at
' their disposal immensely improved
\ appliances, have devoted themselves
I to the enlargement of the boundaries
j of natural knowledge in greater num-
I ber than during any previous half-
century of the world's history.

I have said that our epoch can pro-
duce achievements in physical science

1 •nrTBirBTT-T T r r

QMMiriU««MiBMiMBMa

It;

lO

THE ADVANCE OF SCIENCE

of greater moment than any other ; all such masses of matter possessed
has to show, advisedly ; and I think inertia and were susceptible of ac-
that there are three great products quiring motion, in two ways, firstly
of our time Nv'-ich justify the assertion. ' by impact, or impulse from without;
One of these is that doctrine concern- and, secondly, by the operation of
ing the constitution of matter which, certain hypothetical causes of motion
for want of a better name, I will call termed "forces," which were usually
" molecular ; " the second is the doc- [ supposed to be resident in the parti-
trine of conservation of energy; the i cles of the masses themselves, and to
third is the doctrine of evolution. ' operate at a distance, in such a way
Each of these was foreshadowed, as to tend to draw any two such
more or less distinctly, in former masses together, or to separate them
periods of the history of science, and, more widely.

so far is either from being the out- '. VVitli respect to the ultimate consti-
come of purely inductive reasoning, tution of tliese masses, the snmt' two
that It would be hard to overrate the antagonistic opinions wiiich had ex-
inHuence of metaphysical, and even isted since the time of Deniocritus
of theological, considerations upon and of Aristotle were still face to
the development of ail three. The face. According to the one, matter
peculiar merit of our epoch is that it was discontinuous and consisted of
has siiown how these hypotheses con minute indivisible particles or atoms,
nect a vast number of seemingly in- separated by a universal vacuum ; ac-
dependent partial generalizations ; cording to the other, it was continu-
that it has given them that precision ous, and the finest distinguishable, or
of expression which is necessary for imaginable, particles were scattered
their exact verification ; and that it through the attenuated general sub-
has practically proved their value as stance of the plenum. A rough nnal-
guides to the discovery of new truth, ogy to the latter case would be afford-
All three doctrines are intimately ed by granules of ice diffused through
connected, and each is applicable to water ; to the former, such granules
the whole physical cosmos, l^ut, as diffused through absolutely empty
might have been expected from the space.

nature of the case, the first two grew, ! In the latter part of the eighteenth
mainly, out of the consideration of century, the chemists had arrived at
physico-chemical phenomena; while ^ several very important generalizations
the third, in great measure, owes its respecting those properties of matter
rehabilitation, if not its origin, to the , with which they were especially con-
study of biological phenomena. cerned. However plainly ponderable

matter seemed to be originated and

In the early decades of this cent- ' destroyed in their operations, they
ury, a number of important truths ap- proved that, as mass or body, it re-
plicable, in part, to matter in general, mained indestructible and ingenera-
and, in part, to particular forms of ble ; and that, so far, it varied only in
matter, had been ascertained by the its perceptibility by our senses. The
phvsicists and chemists. ' course of investigation further proved

The laws of motion of visible and , that a certain number of the chemi-
tangible, or molar, matter had been | cally separable kinds of matter were un-
worked out to a great degree of re- alterable by any known means (except
finement and embodied in the branches in so far as they might be made to
of science known as mechanics, hy- , change their state from solid to fluid, or
drostatics, and pneumatics. These | 77?^ zwm), unless they were brought
laws had been shown to hold go'^d, so j into contact with other kinds of matter,
far as they could be checked by ob- j and that the properties of these sev-
servation and experiment, throughout' eral kinds of matter were always the
the universe, on the assumption that same, whatever their origin. All

IN THE LAST HALF-CENTURY.

II

lerable
;d and
IS, they
it re-
enera-
lonly in
The
I proved
chemi-
lere iin-
|(except
iiade to
jrtuid, or
)rought
I matter,
Ise sev-
ivs the
All

other bodies were found to consist of
two or more of these, which thus took
ihe place of the four " elements " of
the ancient philosophers. Further, it
was proved that, in forming chemical
compounds, bodies always unite in a
definite proportion by weight, or in
simple multiples of that proportion,
and tliat, if any one body were taken
as a standard, every other could have
a number assigned to it, as its pro-
portional combining weight. It was
on this fouiKJation of fact that Dalton
based his re-establishment of the old
atomic hypothesis on a new empirical
foundation. It is obvious, that if ele
mentary matter consists of indestruc-
lif)le and indivisible particles, each of
which constantly preserves the same
weight relatively to all the others,
compounds formed by the aggrega-
tion of two, three, four, or more such
particles must exemplify the rule of
combination in definite proportions
deduced from observation.

In the meanwhile, the gradual recep-
tion of the undulatory theory of light
necessitated the assumption of the ex-
istence of an "ether" filling all space.
But whether this ether was to be re-
garded as a strictly material and con-
tinuous substance was an undecided
point, and hence the revived atomism
escaped strangling in its birth. For
it is clear, that if the ether is aclmiiled
to be a continuous material substance,
Democritic atomism is at an end and
Cartesian continuity takes its place.

The real value of the new atomic hy-
pothesis, however, did not lie in the
two points which Democritus and his
followers would have considered essen-
tial— namely, the indivisibility of the
"atoms" and the presence of an inter-
atomic vacuum — but in the assumption
that, to the extent to which our means
of analysis lake ns, material bodies
consist of definite minute masses, each
of which, so far ;;s physical and chem-
ical processes of division go, may be
regarded as a unit — having a practical
pernianent individuality. Just as a
man is the unit of sociology, without
reference to the actual fact of his di-
visibility, so such a minute mass is the

unit of physico-chemical science — that
smallest material panicle which under
any given circumstances acts as a
whole.*

The doctrine erf specific heat orig-
inated in the eighteenth century. It
means that the same mass of a body,
under the same circumstances, alwavs
requires the same quantity of heat to
raise it to a given temperature, but that
equal masses of different bodies re-
quire different quantities. Ultimately,
it was found that the quanlitiesof iieat
required to raise equal masses of the
more perfect gasses, through equal
ranges of temperature, were inverse-
ly proportional to their combining
weights. Thus a definite relation was
established between the iivpothetical
units and heat. The phenomena of
electrolytic decomposition showed that
there was alike close relation between
these Units and electricity. The quan-
titv of electricity generated by the com-
bination of any two units is sufficient to
separate any other two which are sus-
ceptible of such decomposition. The
phenomena of isomorpliism showed a
relation between the units and crystal-
line forms; certain units are thus able
to replace others in a crystalline body
without altering its form, and others
are not.

Again, the laws of the effect of press-
ure and heat on gaseous bf)dies, the
fact that they combine in definite pro-
portions by volume, and that such pro-
portion bears a simple relation to tlieir
combining weights, all harmonized
will) the Daltonian hypothesis, and led
to the bold speculation known as the
law of Avogadio — that all gaseous bod-
ies, under the same physical condi-
tions, contain the same number of
units. In the form in which it was
first enunciated, this hypothesis was
incorrect — perliajis it is not exactly
true in any form ; but it is hardly too
much to say that chemistry and mo-

j *" M(il< rule "would l)c the inoio anpropr'-
I ate iKiini' liir Mich ;\ iiarticlc. UntOrttipatelv,
chemists cinphiy this trim in a spc-ial sense,
j as a n.iim' for :)n n'/tiretiation of tlicir siiiil'i st
i partich's. for whicli ihcy i':taii> tiic clusiL^ii.iliun
■ ol ".Uoins."

13

THE ADVANCE OF SCIENCE

lecular physics would never have ad-
vanced to their present condition un>
less it had been assumed to be true.
Another immense service rendered by
Dalton, as a corollary of the new atom-
ic doctrine, was the creation of a sys-
tem of symbolic notation, which not
only made the nature of chemical com-

{)ouncls and processes easily intelligi-
)le and easy of recollection, but, by
its very form, suggested new lines of
inquiry. The atomic notation was as
serviceable to chemistry as the binom-
ial nomenclature and the classifrca-
tory schematism of Linna:us were to
zoology and botany.

Side by side with these advances
arose Another, which also h^s a close
parallel in the history ot biological
science. If the unit ot a compound
is made up by the aggregation of ele-
mentary units, the notion that these
must have some sort of definite ar-
rangement inevitably suggests itseli ;
and such phenomena as double de-
composition pointed not only to the
existence of a molecular architecture,
but to the possibility of modifying a
molecular fabric without destroying it,
by taking out some of the component
units and replacing them by others.
The class of neutral saltS, for exam-
ple, includes a great number of bodies
in many ways similar, in which the
basic molecules, or the acid mole-
cules, may be replaced by other basic
and other acid molecules without al-
tering the neutrality of the salt ; just
as a cube of bricks remains a cube,
so long as any brick that is taken out
is replaced by another of the same
shape and dimensions, whatever its
weight or other properties may be.
Facts of this kind gave rise to the
conception of " types " of molecular
structure, just as the recognition of
the unity in diversity of the structure
,of the species of plants and animals
gave rise to the notion of biological
i" types." The notation of chemistry
enabled these ideas to be represented
with precision ; and they acquired an
immense importance, when the im-
provement of methods of analysis,
which took place about the beginning

of our period, enabled the composi-
tion of the so-called " organic " bodies
to be determined with rapidity and
precision.* A large proportion of
these compounds contain not more
than three or four elements, of which
carbon is the chief ; but their num-
ber is very great, and the diversity of
their physical and chemical proper-
ties is astonishing. The ascertain-
ment of the proportion of each ele-
ment in these compounds affords little
or no help toward accounting for
their diversities; widely different bod-
ies being often very similar, or even
identical, in that respect. And, in
the last case, that of isomeric com-
pounds, the appeal to dive;sity of ar-
rangement of the identical compo-
nent units was the only obvious way
out of the difficulty. Here, again,
hypothesis proved to be of great
value ; not only was the search for
evidence of diversity of molecular
structure successful, but the study of
the process of taking to pieces led to
the discovery of the way to put to-
gether ; and vast numbers of com-
pounds, some of them previously
known only as products of the living
economy, have thus been artificially
constructed. Chemical work, at the
present day, is, to a large extent, syn-
thetic or creative — that is to say, the
chemist determines, theoretically,
that certain non-existent compounds
ought to be producible, and he pro-
ceeds to produce them.

It is largely because the chemical
theory and practice of our epoch
have passed into this deductive and
synthetic stage, tl.at they are entitled
to the name of the " new chemistry "
which they commonly received. But
this new chemistry has grown up by
the help of hypotheses, such as those
of Dalton and of Avogadro, and that
singular conception of " bonds " in-
vented to colligate the facts of "val-
ency " or " atomicity," the first of

* " At present more organic analyses are
made in a single day than were accomplished
before Liebig's time in a whole year." — Hof-
mann, Faraday Lecture, p. 46.

IN THE LAST HALF-CENTURY.

13

nposi-

)odies

y and

ion of
more

which
num-

sity of

)roper-

ertauv

;h de-
ls Uttle

ng for

ntbod-

r even

^nd, in

c com-

: of ar-

conipo-

)us way

again,

great

.rch for

olecular

study of

i led to
put to-

of coni-

eviously

e living

tificially
, at the
nt, syn-
say, the
etically,
ipounds
he pro-
chemical
epoch
Itive and
entitled
fmistry "
:d. But
in up by
las those
land that
ids" in-
of " val-
first of

[alyses are
jmplished
•— Ho!-

which took some time to make its
way; while the second fell into obliv-
ion, for many years after it was pro-
pounded, for lack of empirical justifi-
cation. As for the third, it may be
doubted if anyone regards it as more
than a temporary contrivance.

But some of these hypotheses have
done yet further service. Combining
them with the mechanical theory of
heat and the doctrine of the conser
vation of energy, which are also pro-
ducts of our time, physicists have ar-
rived at an entirely new conception
of the nature of gaseous bodies and
of the relation of the physico-chemi-
cal units of matter to the different
forms of energy. The conduct of
gases under varying pressure and
temperature, their diffusibility, their
relation to radiant heat and to light,
the evolution of heat when bodies
combine, the absorption of heat when
they are dissociated, and a host of
other molecular phenomena, have
been shown to be deducible from the
dynamical and statical principles
which apply to molar motion and
rest; and the tendency of physico-
chemical science is clearly toward
the reduction of the problems of the
world of the infinitely little, as it al-
ready has reduced those of the infi-
nitely great world, to questions of
mechanics.*

In the meanwhile, the primitive
atomic theory, which has served as
the scaffolding for the edifice of mod-
ern physics and chemistry, has been
quietly dismissed. I cannot discover
that any contemporary physicist or
chemist believes in the real indivisi-
bility of atoms, or in an interatomic
matterless vacuum. " Atoms " ap-
pear to be used as mere names for
physico-chemical units which have
not yet been subdivided, and " mole-
cules " for physico-chemical units

• In the preface to his Af/canique Chimi-
que M. Berthelot declares his object to be
" ramener la chimic tout entitre . . . .
aux memes principes mecaniques qui re-
gissent d^j^ les diverses branches de la phy-
sique."

which are aggregates of the former.
And these individualized particles are
supposed to move in r.ii endless ocean
of a vastly more subtle matter — tne
ether. If this ether is a continuous
substance, therefore, we have got back
from the hypothesis of Dalton to that
of Descartes. But there is much rea-
son to believe that science is going
to make a still further journey, and,
in form, if not altogether in substance,
to return to the point of view of Aris-
totle.

The greater number of -the so-
called " elementary " bodies, now
known, had been discovered before
the commencement of our epoch ,
and it had become apparent that they
were by no means equally similar or
dissimilar, but that some of them, at
any rate, constituted groups, the sev-
eral members of which were as much
like one another as they were unlike
the rest. Chlorine, iodine, bromine,
and fluorine thus formed a very dis-
tinct group; sulphur and selenium
another; boron and silicon another;
potassium, sodium, and lithium an-
other ; and so on. In some cases,
the atomic weights of such allied
bodies were nearly the same or could
be arranged in series, with like dif-
ferenceJ between the several terms.
In fact, the elements afforded indica-
tions that they were susceptible of a
classification in natural groups, such
as those into which animals and
plants fall.

Recently this subject has been
taken up afresh, with a result which
may be stated roughly in the follow-
ing terms: If the sixty-five or sixty-
eight recognized "elements" are
arranged in the order of their atomic
weights — from hydrogen, the lightest,
as unity, to uranium, the heaviest, as
240 — the series does not exhibit one
continuous progressive modification
in the physical and chemical charac-
ters of its several terms, but breaks
up into a number of sections, in each
of which the several terms present
analogies with the corresponding
terms of the other series.

mmm»

H

Thus
run

THE ADVANCE OF SCIENCE

the whole series does not

a, 6, c, J, f,/, g, //, /, k, etc.,

but

a, d, r, d, a, b, c, d, «, Pt 7, •J. etc. ;

so that it is said to express ^periodic
laiv of recurrent similarities. Or the
relation may be expressed in another
way. In each section of the series,
the atomic weight is greater than in
the preceding section, so that if w is
the atomic weight of any element in
the first segment, w-\-x will represent
the atomic weight of any element in
the next, and w-\-x-\-y the atomic
weight of any element in the next,
and so on. Therefore the sections
may be represented as parallel series,
the corresponding terms of which
have analogous properties , each suc-
cessive series starling with a body the
atomic weight of which is greater
than th^t of any in the preceding
series, in the following fashion :

d
c
h
a

w

D
C

B
A

7

P
a

ttf+x w+x+y

This is a conception with which
biologists are very familiar, animal
and plant groups constantly appearing
as series of parallel modifications of
similar and yet different primary
forms. In the living world, facts of
this kind are now understood to mean
evolution from a common prototype.
It is difficult to imagine that in the
not-living world they are devoid of
significance. Is it not possible, nay
probable, that they may mean the
evolution of our "elements'" from a
primary undifferentiated form of
matter ? Fifty years ago, such a sug-
gestion would have been scouted as
a revival of the dreams of the alche-
mists. At present, it may be said to

be the burning question of physico-
chemical science.

In fact, the so-called " vortex-ring "
hypothesis is a very serious and re-
markable attempt to deal with mate-
rial units from a point of view which
is consistent with the doctrine of evo-
lution. It supposes the ether to be
a uniform substance, and that the
" elementary " uniis are, broadly
speaking, permanent whirlpools, or
vortices, of this ether, the properties
of which depend on their actual and
potential modes of motion. It is
curious and highly interesting to re-
mark that this hypothesis reminds us
not only of the speculations of Des-
cartes, but of those of Aristotle.
The resemblance of the " vortex-
rings " to the " tourbillons " of Des-
cartes is little more than nominal ;
but the correspondence between the
modern and the ancient notion of a
distinction between primary and de-
rivative matter is, to a certain extent,
real. For this ethereal " Urstoff " of
the modern corresponds very closely
with the niMr?}v/.i/ of Aristotle, the
materia prima of his mediaeval follow-
ers ; wliile matter, differentiated into
our elements, is the equivalent of the
first stage of progress towards the
tax^'^n i>'/, or finished matter, of the
ancient philosophy.

If the material units of the existing
order of nature are specialized por-
tions of a relatively homogeneous ma-
teriaprima — which were originated un-
der conditions that have long ceased
to exist and which remain unchanged
and unchangeable under all conditions,
whether natural or artificial, hitherto
known to us — it follows that the spec-
ulation that they may be indefinitely
altered, or that new units may be gen-
erated under conditions yet to be dis-
covered, is perfectly legitimate. The-
oretic'dly, at any rate, the transmuta-
bility of the elements is a verifiable
scientific hypothesis ; and such inquir-
ies as those which have been set afoot,
into the possible dissociative action of
the great heat of the sun upon our ele-
ments, are not only legitimate, but are
likely to yield results which whether af-

IN THE LAST HALF-CENTURY.

15

jxisting
.'d por-
)us ma-
itedun-

ceased
hanged
][litions,

lilherto

firmative or negative will be of great
importance. The idea that atoms
are absolutely ingenerable and immu-
table "manufactured articles" stands
on the same sort of foundation as the
idea that biological species are
" manufactured articles " stood thirty
years ago ; and the supposed constan-
cy of the elementary atoms, durini;
the enormous lapse of time measured
by the existence of our universe, is of
no more weight against the possibility
of change in them, in the infinity of
antecedent time, than the constancy
of species in Kgypt, since the days of
Rameses or Cheops, is evidence of
their immutability during all past
epochs of the earth's history. It
seems safe to prophesy that the hy-
pothesis of the evolution of the ele-
ments from a primitive matter will, in
future, play no less a part in the his-
tory of science than the atomic hy-
pothesis, v.iuch, to bei;in with, had no
greater, if so great, an empirical fonn
dation.

It may perhaps occur to the reader
that the boasted progress of physical
science does not come to much, if
our present conceptions of the funda-
mental nature of matter are expressi-
ble in terms employed, more than two
thousand years ago, by the old " mas-
ter of those that know." Such a
criticism, however, would involve for-
getfulness of the fact, that the conno-
tation of these terms, in the mind of
the modern, is almost infinitelv differ-
ent from that which they possessed in
the mind of the ancient, philosopher.
In antiquity, they meant little more
than vague speculation ; at the pres-
ent day, they indicate definite physi-
cal conceptions, susceptible of mathe-
matical treatment, and giving rise to
innumerable deductions, the value of
which can be experimentally tested.
The old notions produced little more
than floods of dialectics ; the new are
powerful aids toward the increase of
solid knowledge.

Everyday observation shows that,
of the bodies which compose the ma-
terial world, some are in motion and
some are, or appear to be, at rest.

C the bodies in motion, some, like
the sun and stars, exhibit a constant
movement, regular in amount and
direction, for which no external cause
appears. Others, as stones and
smoke, seem also to move of them-
selves when external impediments are
taken away. But these appear to
tend to move in opposite directions :
the bodies we call heavy, such as
stones, downwards, and the bodies we
call light, at le.ist such as smoke and
steam, upwards. And, as we further
notice that the earth, below our feet,
is made up of heavy matter, while the
air, above our heads, is extremely
light matter, it is easy to regard this
fact as evidence that the lower rej^ion
is the place to which heavy things
tend — their ])roper place, in short —
while the upper region is the proper
place of light things ; and to general-
ize the facts observed by saying that
bodies, which are free to move, tend
toward their proper places. Ail these
seem to be natural moirrtns, depend-
ent on the inherent faculties, or ten-
dencies, of bodies themselves. But
there are other motions which are
artificial or violent, as when a stone
is thrown from the hand, or is knocked
by another stone in motion. In such
cases as these, for example, when a
stone is cast from the hand, the dis-
tance traveled by the stone appears
to depend partly on its weight and
partly upon the exertion of the throw-
er. So that, the weight of the stone
remaining the same, it looks as if the
motive power communicated to it
were measured by the distance to
which the stone travels — as if, in
other words, the power needed to
send it a hundred yards was twice as
great as that needed to send it fifty
yards. These, apparently obvious,
conclusions from the everyday ap-
pearances of rest and motion fairly
represent the state of opinion upon
the subject which prevailed among
the ancient Greeks, and remained
dominant until the age of Galileo.
The publication of the " Principia " of
Newton, in 1686-7, marks the epoch
at which the progress of mechanical

1^

THE ADVANCE OF SCIENCE

physics had effected a complete rev-
olution of thought on these subjects.
By this time, it had been made clear
that the old generalizations were
either incomplete or totally errone-
ous ; that a body, once set in motion,
will continue to move in a straight
line for any conceivable time or dis-
tance, unless it is interfered with ;
that any change of motion is propor-
tional to the " force " which causes it,
and takes place in the direction in
which that " force " is exerted ; and
that, when a body in motion acts as
a cause of motion on another, the
latter gains as much as the former
loses, and Tice versa. It is to be
noted, however, that while, in con-
tradistinction to the ancient idea of
the inherent tendency to motion of
bodies, the absence of any such spon-
taneous power of motion was accepted
as a physical axiom by the moderns,
the old conception virtually main-
tained itselt in a new shape. For, in
spite of Newton's well-known warn-
ing against the "absurdity" of sup-
posing that one body can act on
another at a distance through a va-
cuum, the ultimate particles of matter
were generally assumed to be the
seats of pe ennial causes of motion
termed " attractive and. repulsive
forces," in virtue of which, any two
such particles, without any external
impression of motion, or intermediate
material agent, were supposed to tend
to approach or remove from one an-
other ; and this view of the duality of
the causes of motion is very widely
held at the present day.

Another important result of inves-
tigation, attained in the seventeenth
century, was the proof and quantita-
tive estimat'on of physical inertia.
In the old philosophy, a curious con-
junction of ethical and physical prej-
udices had led to the notion that
there was something ethically bad
and physically obstructive about
matter. Aristotle attributes all ir-
regularities and apparent dysteleolo-
gies in nature to the disobedience,
or sluggish yielding, of matter to the
shaping and guiding influence of

those reasons and causes which were
hypostatized in his ideal "forms."
In modern science, the conception of
the inertia, or resistance to change,
of matter is complex. In part, it
contains a corollary from the law of
causation : A body cannot change
its state in respect of rest or motion
without a sufficient cause. But, in
part, it contains generalizations from
experience. One of these is that
there is no such sufficient cause resi-
dent in any body, and that therefore
it will rest, or continue in motion, so
long as no external cause of change
acts upon it. The other is that the
effect which the impact of a body in
motion produces upon the body on
which it impinges depends, other
things being alike, on the relation of
a certain quality of each which is
called " mass." Given a cause of
motion of a certain value, the amount
of motion, measured by distance trav-
eled in a certain time, which it will
produce in a given quantity of matter,
say a cubic inch, is not always the
same, but depends on what that mat-
ter is — a cubic inch of iron will go
faster than a cubic inch of gold.
Hence, it appears, that since equal
amounts of motion have, ex hypothcsi,
been produced, the amount of motion
in a body does not depend on its
speed alone, but on some property of
the body. To this the name of
" mass " has been given. And since
it seems reasonable to suppose that a
large quantity of matter, moving
slowly, possesses as much motion as
a small quantity moving faster,
" mass " has been held to express
"quantity of matter." It is further
demonstrable that, at any given time
and place, the relative mass of any
two bodies is expressed by the ratio
of their weights.

When all these great truths respect-
ing molar motion, or the movements
of visible and tangible masses, had
been shown to hold good not only of
terrestrial bodies, but of all those
which constitute the visible universe,
and the movements of the macrocosm
had thus been expressed by a general

ilil

IN THE LAST IIAI.F-CEN'TURY.

»7

1 were

arms."

ion of

hange,

lart, it

law of

change

motion

But, in

s from

is that

se resi-

lerefore

tion, so

change

hat the

body in

)ody on

;, other

ation of

vhich is

;ause of

I amount

nee trav-

h it will

if matter,

A'ays the

hat mat-

} will go

of gold.

ce equal

hypothcsiy
' motion
on its
iperty of
lame of
nd since
se that a
moving
otion as
faster,
express
further
ven time
of any
the ratio

respect-
jvements
^ses, had
|)t only of
ill those
luniverse,

icrocosm
general

n

mechanical theory, there remained a
vast number of phenomena, such as
those of light, heat, electricity, mag-
netism, and those of the physical and
chemical changes, which clo not in-
volve molar moiion. Newton's cor-
puscular theory of light was an at-
tempt to deal with one great series of
these phenomena on mechanical prin-
ciples, and it maintained its ground un-
til, at the beginning of the nineteenth
century, the undulatory theory proved
itself to be a much better working
hypothesis. Heat, up to that time,
and indeed much later, was regarded
as an imponderable substance, caloric ;
as a thing which was absorbed by
bodies when they were warmed, and
was given out as they cooled ; and
which, moreover, was capable of en-
tering into a sort of chemical com-
bination with them, and so becoming
latent. Rumford and Davy had
given a great blow to this view of heat
by proving that the quantity of heat
which two portions of the same body
could be made to give out, by rubbing
them together, was practically illimi-
table. This result brought philoso-
phers face to face with the contradic-
tion of supposing that a finite body
could contain an infinite quantity of
another body; but it was not until
1843, that clear and unquestionable
experimental proof was given of the
fact that there is a definite relation
between mechanical work and heat ;
that so much work always gives rise,
under the same conditions, to so much
heat, and so much heat to so much
mechanical work. Thus originated
the mechanical theory of heat, which
became the starting-point of the mod-
ern doctrine of the conservation of
energy. Molar motion had appeared
to be destroyed by friction. It was
proved that no destruction took place,
but that an exact equivalent of the
energy of the lost molar motion ap-
pears as that of the molecular motion,
or motion of the smallest particles of
a bod}', which constitutes heat. The
loss of the masses is the gain of their
particles.
Before 1843, however, the doctrine

of the conservation of energy had
been approached. Bacon's chief con-
tribution to positive science is the
happy guess (for the context shows
that it was little more) that hent
may be a mode of motion ; Descartes
affirmed the quantity of motion in
the world to be constant ; Newton
nearly gave expression to the com-
plete theorem ; while Rumford's and
Davy's experiments suggested, though
they did not prove, the equivalency
of mechanical and thermal energy.
Again, the discovery of voltaic elec-
tricity, and the marvelous develop-
ment of knowledge, in that field,
effected by such men as Davy, Fara
day. Oersted, Ampere, and Melloni,
had brought to light a number of facts
which tended to show that the so-
called •' forces " at work in light, heat,
electricity, and magnetism, in chemi-
cal and in mechanical operations,
were intimately, and, in various cases,
quantitatively related. It was demon-
strated that any one could be ob-
tained at the expense of any other ;
and apparatus was devised which ex-
hil?ited the evolution of all these kinds
of action from one source of energy.
Hence the idea of the " correlation
of forces " which was the immediate
forerunner of the doctrine of the con-
servation of energy. ^^
It is a remarkable evidence of the
greatness of the progress in this direc-
tion which has been effected in our
time, that even the second edition of
the " History of the Inductive Scien-
ces," which was published in 1846,
contains no allusion either to the gen-
eral view of the "Correlation of
Forces " published in England in
1842, or to the publication in 1843 of
the first of the series of experiments
by which the mechanical equivalent
of heat was correctly ascertained.*

• This is the more curious, as Amptre'H-
hypothcsis that vibrations of molecules,
causing and caused by vibrations of the
ether, constitute heat, is discussed. See vol.
ii. p. 587, 2nd ed. In the Philosophy of the
Inductwe Sciences, 2nd ed.. 1847, p. 239,.
Whewell remarks, h propos of ISacon's defini--
tion of beat, " that it ia an expansive, re-

i8

Till-: ADVANCE OF SCIENCE

Such a failure on the part of a con-
Icmpfirary, of j^roat ac(|uiremems and
rcmaikable iiucllccuial powers, to
read ihc signs of the times, is a li'sson
and a wainini; worthy of being deeply
Ijondered by anyone who attempts to
pro{;noslicaie the course of scientific
progress.

1 have pointed out that the growth
of clear and delinite views respecting
the constitution of matter has led to
the conclusion that, so far as natural
agencies are concerned, it is ingener-
ai)le and indestructible. In so far as
matter may be conceived to exist in a
purely passive state, it is, imaguiably,
older than motion. But, as it must
be assumed to be .susceptible of mo-
tion, a particle of bare matter at rest
must be endowed wuh the potentiality
of motion. Such a panicle, however,
by the supposition, can iiave no en-
tirgy, for there is no cause why it
should move. Suppose now that it
receives an impulse, it will begin to
move with a velocity inversely pro-
portional to Its mass, on the one
hand, and directly jiroportional to the
strength of the impulse, on the other,
and will j^ossess kinetic energy, in vir-
tue of which it will not only continue
to move forever if unimpeded, but if
it impinges on another such particle,
it will impart more or less of its mo-
tion to the latter. Let it be conceived
that the particle acquires a tendency
to move, and that nevertheless it does
not move. It is then in a condition
totally different from that in which it
was at first. A cause competent to
produce motion is operating upon it,
but, for some reason or other, is un
able to give rise to motion. If the

strained motion, modified in certain w.ays,
and exerted in the smaller particles of the
body;" that "although the exact nature of
heat is still an obscure and controverted
matter, the science of heat now consists of
many imjiortant truths ; and that to none of
these truths is there any approximation in
l?acon's essay." In point of fact, Hacon's
statemrnt, however much open to criticism,
does contain a distinct approximation to the
most important of all the truths respecting
heat which had been discovered when
Whewell wrote.

obstacle is removed, the energy which
was there, but could not manifest it-
self, at once gives rise to motion.
While the restraint lasts, the energy
of the particle is merely potential ;
and the case supjiosed illustrates wiiai
is meant by potential energy. In this
contrast of the potential with the actual,
modern physics is turning to account
the most familiar of Aristotelian dis-
tinctions— that between <''k'/"V and

That kinetic energy appears to be
im|)arted by impact is a fact of daily
and hourly experience : we see bodies
set in motion by bodies, already in
motion, which seem to come in
contact with them. It is a truth
which could have been learned by
nothing but experience, and which
cannot be explained, but must be
taken as an ultimate fact about which,
explicable or inexplicable, there can
be no doubt. Strictly speaking, we
have no direct apprehension of any
other cause of motion. But experi-
ence furnishes innumerable examples
of the production of kinetic energy in
a body previously at rest, when no
impact is discernible as the cause of
that energy. In all such cases, the
presence of a second body is a neces-
sary condition ; and the amount of
kinetic energy, which its presence en-
ables the first to gain, is strictly de-
pendent on the relative positions of
the two. Hence the phrase etiergy of
position, which is frequently used as
equivalent to potential energy. If a
stone is picked up and held, say, six
feet above the ground, it hti'-, potential
energy, because, if let go, it will imme-
diately begin to move toward the
earth ; and this energy may be said to
be energy of position, because it de-
pends upon the relative position of
the earth and the stone. The stone
solicited to move but cannot, so

IS

long as the muscular strength of the
holder prevents the solicitation from
taking effect. The stone, therefore,
has potential energy, which becomes
kinetic if it is let go, and the amount
of that kinetic energy which will be
develooed before it strikes the earth

IN THE LAST HALF-CKNTURY.

19

lot, so
hi the

from
efore,
tomes

(lount
till be
[earth

depends on its position — on the fact ' right-hand half-swing. It is said that
that it is, say, six feel off the earth, , the "attractive forces" of tlie bob
neiiix.T more nor less. Moreover, it for the earth, and of the earth for the
can be proved that the raiser of liie bol), set the former in motion ; and
stone had to exert as much energy in j as tliese " forces " are continually in
order to place it in its position, as it operation, they confer an accelerated
will (Lvclop in falling. Hence the velocity on the bob; until, when it
energy which was exerted, and reaches the center of its swing, it is.
apparently exhausted, in raising , so to speak, fully charged with kinetic
the slouL', is_ pottMUially in the stone, ; energy. If, at this moment, the
in its laisod position, and will m an i- whole material universe, except the
fest itself when the stone is set free, bob, were abolished, it would move
Thus the energy, wiilulrawn from the 1 forever in the direction of a tangent
general stf)ck to raise the stone, isre-jto the middle of the arc described,
turned when it falls, and there is no 1 As a matter of fact, it is comjielled to
changL' in the total amount. Energy, I travel through its left-hand half-swing,
as a whoK', is conserved. ! and thus virtually to go up hill.

Taking this as a very broad and Consequently, the " attractive forces "
general stalenieiu of the essential of the bob and the earth are now
facts of tiie case, the raising of the acting against it, and constitute a
stone is inieliigible enough, as a case I resistance which the charge of kinetic
of the comnnniicalion of motion from energy has to overcome. IJut. as this
one body to another. But the poten- charge represents the operation of
tial energy of the raised stone is not , the attractive forces during the pns-
so easily intelligible. To all appear- sage of the bob through the right-
ance, there is nt)thing either pushing; hand half-swing down to the center of
or pulling it toward the earth, or the arc, so it must needs be used up
the earth toward it; and yet it is |by the passage of the bob upwards
quite certain that the stone tends to from the center of the arc to the sum-
move toward the earth and the earth ' niit of the left-hand half-swing,
toward the stone, in the way detined ; Hence, at this point, the bob comes
by the law of gravitation. to a momentary rest. The last frac-

In the currently accepted language tion of kinetic energy is just neutral-
of science, the cause of motion, in all '■ ized by the action of the attractive
such cases as this, when bodies tend forces, and the bob has only pottMitial
to move toward or away from one or , energv equal to that with which it
another, without any discernible im- , started. So that the sum of the phe-
pact of other bodies, is termed a i nomena may be stated thus: At the
" force," which is called " attractive " \ summit of either half arc of its swing,
in the one case, and " repulsive " in ' the bob has a certain amount of po-
the other. And such attractive or , tential energy ; as it descends it grad-
repvdsive forces are often spoken of ; ually exchanges this for kinetic en-
as if they were real things, capable of.ergv, until at the center it possesses
exerting a pull, or a push, upon the | an equivalent amount of kinetic en-
particles of matter concerned. Thus ergv ; from this point onwards, it
the potential energy of the stone is gradually loses kinetic energy as it
commonly said to be due to the ascends, until, at the summit of the
"force" of gravity which is contin- 1 other half-arc, it has acquired an ex-
ually operating upon it. aclly similar amount of potential en-

Another illustration may make the ergy Thus, on the whole transaction,
casa plainer. The bob of a pendu- , nothing is either lost or gained ; the
lum swings first to one side and then j quantity of energy is always the same,
to the other of the center of the arc 1 but it passes from one form into the
which It describes. Suppose it to ; other,
have just reached the summit of its I To all appearance, the phenomena

■•^

WW

20

THE ADVANCE OF SCIENCE

exhibited by the pendulum are not to
be accounted for by impaci ; in fact,
it is usually assumed that correspond-
'ing phenomena would take place if
the earth and the pendulum were sit-
uated in an absolute vacuum, and at
any conceivable distance from one
another. If this be so, it follows that
there must be two totally different
kmds of causes of motion : the one
impact — a vera causa, of which, to all
appearance, we have constant expe-
rience ; the other, attractive or repul-
sive "force" — a metaphysical entity
which is physically inconceivable.
Newton expressly repudiated the no-
tion of the existence of attractive
forces in the sense in which that term
is ordinarily understood \ and he re-
fused to put forward any hypothesis
as to the physical cause of the so-
called " attraction of gravitation."
As a general rule, his successors have
been content to accept the doctrine
of attractive and repulsive forces,
without troubling themselves about
the philosophical difficulties which it
involves. But this has not always
been the case ; and the attempt of Le
Sage, in the last century, to show that
the phenomena of attraction and re-
pulsion are susceptible of explanation
by hi^ hypothesis of bombardment by
ultra-mundane particles, whether ten-
able or not, has the great merit of
being an attempt to get rid of the
dual conception of the causes of mo-
tion which has hitherto prevailed.
On this hypothesis, the hammering of
the ultra-mundane corpuscles on the
bob confers its kinetic energy, on the
one hand, and takes it away on the
other; and the state of potential en-
ergy means the condition of the bob
during the instant at which the
energy, conferred by the hammering
during the one half-arc, has just been
exhausted by the hammering during
the other half-arc. It seems safe to
look forward to the time when the
conception of attractive and repulsive
forces, having served its purpose as a
useful piece of scientific scaffolding,
will be replaced by the deduction of
the phenomena known as attraction

and repulsion, from the general laws
of motion.

The doctrine of the conservation of
energy which I have endeavored to
illustrate is thus defined by the late
Clerk Maxwell :

" The total energy of any body or
system of bodies is a quantity which
can neither be increased nor dimin-
ished by any mutual action of such
bodies, though it may be transformed
into any one of the forms of which
energy is susceptible." It follows
that energy, like matter, is indesiruci-
iRIe and mgenerable in nature. The
Ijlienomenal world, so far as it is
material, expresses the evolution and
involution of energy, its passage from
the kinetic to the potential condition
and back again. Wherever motion
of matter takes place, that motion is
effected at the expense of part of
the total store of energy.

Hence, as the phenomena exhibi-
ted by living beings, in so far as they
are material, are all molar or molec-
ular motions, these are included un-
der the general law. A living body is
a machine by which energy is trans-
formed in the same sense as a steam-
engine is so, and all its movements,
molar and molecular, are to be ac-
counted for by the energy which is
supplied to it. The phenomena of
consciousness which arise, along with
certain transformations of energy,
cannot be interpolated in the series
of these transformations, inasmuch as
they are not motions to which the doc-
trine of the conservation of energy
applies. And, for the same reason,
they do not necessitate the using up
of energy ; a sensation has no mass
and cannot be conceived to be sus-
ceptible of movement. That a par-
ticular molecular motion does give
rise to a state of consciousness is ex-
perimentally certain ; but the how
and why of the process are just as in-
explicable as in the case of the com-
munication of kinetic energy by im-
pact.

When dealing with the doctrine of
the ultimate constitution of matter,
we found a certain resemblance be-

IN THE LAST HALF-CENTURY.

21

|-ine of
latter,
:e be-

tween the oldest speculations and
the newest doctrines of physical phi-
losophers. But there is no such re-
semblance between the ancient and
modern views of motion and its
causes, except in so far as the concep-
tion of attractive and repulsive forces
may be regarded as the modified de-
scendant of the Aristotelian concep-
tion of forms. In fact, it is hardly
loo much to say that the essential
and fundamental difference between
ancient and modern physical science
lies in the ascertainment of the true
laws of statics and dynamics in the
course of the last three centuries ;
and in the invention of matiiematical
methods of dealing with all the con
sequences of these laws. The ulti-
mate aim of modern physical science
is the deduction of the phenomena ex-
hibited by material bodies from phy
sico-mathematical first principles.
Whether the human intellect is strong
enough to attain the goal set before it
may be a question, but thither will it
surely strive.

The third great scientific event of
our time, the rehabilitation of the
doctrine of evolution, is part of the
same tendency of increasing knowl-
edge to unify itself, which has led to
the doctrine of the conservation of
energy. And this tendency, again,
is mamly a product of the increasing
strength conferred by physical inves-
tigation on the belief in the universal
validity of that orderly relation of
facts, which we express by the so-
called " laws of nature."

The growth of a plant from its
seed, of an animal from its egg, the
apparent origin of innumerable living
things from mud, or from the putre-
fying remains of former organisms,
had furnished the earlier scientific
thinkers with abundant analogies
suggestive of the conception of a cor-
responding method of cosmic evolu-
tion from a formless " chaos " to an
ordered world which might either con-
tinue forever or undergo dissolution
into its elements before starting on a
new course of evolution. It is there-

fore no wonder that, from the days o£
the Ionian school onwards, the view
that the universe was the result of
such a process should have muiu-
lained itself as a leading dogma uf
philosophy. The emanistic theories
which played so great a part in Nto-
platonic philosop'.iy and (Inostic the-
ology are forms of evolution. In the
seventeenth century, Descartes pro-
pounded a scheme of evolution, as an
hypothesis of what might have been
the mode of origin of the world, while
professing to accept the ecclesiastical
scheme of creation, as an account of
that which actually was its manner of
commg into existence. In the eigh-
teenth century, Kant put forth a re-
markable speculation as to the origin
of the solar system, closely similar to
that subsequently adopted by Laplace
and destined to become famous under
the title of the " nebular hypothesis."

The careful observations and the
acute reasonings of the Italian geolo-
gists of the seventeenth and eigh-
teenth centuries; the speculation.s of
Leibnitz in the " Protoga;a " and of
Huffon in his " Theorie de la Terre ; "
the sober and profound reasonings of
Hutton, in the latter part of the eigh-
teenth century ; all these tended to
show that the fabric of the earth it-
self implied the continuance of pro-
cesses of natural causation for a
period of time as great, in relation to
human history, as the distances o£
the heavenly bodies from us are, in
relation to terrestrial standards of
measurement. The abyss of time
began to loom as large as the abyss
of space. And this revelation to
sight and touch, of a link here and a
link there of a practically infinite
chain of natural causes and effects,
prepared the way, as perhaps nothing
else has done, for the modern form of
the ancient theory of evolution.

In the beginning of the eighteenth
century, De Maillet made the fir.st
serious attempt to apply the doctrine
to the living world. In the latter
part of it, Erasmus Darwin, Goethe,
Treviranus, and Lamarck took up the
work more vigorously and with better

22

THE ADVANCE OF SCIENCE

qualifications. The question of spe-
cial creation, or evolmion, lay at tiic
liMttoin of \hc fierce (lis|ju!i.'s which
biolvO ont in llic l-'rcnch AcadLiny be-
tween Ciivicr and St.-Hilaire ; and,
for a time, llie supporters of biojoyi-
cal evohition were silenced, if not
answered, by tlie alliance of the j;reat-

tion, among the hi{;hest forms of each
;;r(iiip. In fact, in endeavoring to
support these views he went a good
way beyond the limits of any cautious
interpretation of the facts then known.
Althoiijih little acquainted with
bio|()>;iciil science, Whewell seems to
have taken particular pains with tliat

est naturalist of the age with their j jiart of his work whi(h deals with the

ec( lesiaslical

phisin, a short-sighted teleology, and

opponents. (!atasiro- 1 history of geological and biolo;iical

spt

lory oi
.'culalio

n ; and several chapters of
a still more short-si;;hted orthodoxy, ' his seventeenth and eigthleenth books,

Joined forces to crush evolution.

I,yell and I'oulett Scrope, in this
( omitry, resumed the work of the
Il.dians and of Ilutton ; and the for-
mer, aided by a niarvelous power of
clear exposiiion, placed upon an irre-
fragable basis the truth that natural
causes are competent to account for
all events, which can be proved to
have occurred, in the course of the
s(.'cular changes which have taken
))la<i' during the deposition of the
sUatilicd rocks. 'J"he publication of
*' The principles of (jeology," in
18^0, consliiuted an ejioch in ge(:
ical science. iJut it also constituted
an epoch in the modern history of the
doctrines of evolution, by raising in
the mind of every intelligoiU reader
this question ; If natural causation is
oonqx'tenl to account for the not-liv-
ing part of our globe, why should it
not account for tiie living part?

1)V keeping this {|uestion before the
public for some thirty years, Lyell,
though the keenest and most formi-
dable of the opponents of the trans-
nuitntion theory, as it was formulated
by Lamarck, was of the greatest pos-
sible service in facilitating the recep-
tion of the sounder doctrines of a
later day. And, in like fashion,
another vehement opponent of the
transmutaticn of species, the elder
Agassiz, was doomed to help the
cause he hated. Agnssiz not onlv
maintained the fact of the progressive
advance in organization of the inh.nb-
itants of the earth at each successive
geological epoch, but he insisted up-
on the analogy of the steps of this
progression with those by which the
embryo advances to the adult coiuli-

og- 1 the

which comprise the history of physi-
ology, of comparative anatomy and
of the pallet iological scieiu es, vividly
reproduce the controversies of the
early days of the Victorian epoch.
Hut here, as in the case of the doc-
trine of the conservati(Mi of energy,
llie historian of the inductive sciences
has no prophetic insight ; not even a
suspicion of that which the near fut-
ure was to bring forth. And those
who still repeat the once favorite ob-
jection that Darwin's "Oiigin of Spe-
cies " is nothing but a new version of
" I'hilosophie zoologique " will
find that, so late as 1844, Whewell
had not the slightest suspicion of
Darwin's main theorem, even as a
logical possibility. In fact, the pub-
lica:i<in of that theorem by Darwin
and Wallace, in 1859, took all the
biological world by surprise. Neither
those who were inclined toward the
''progressive transmutation " or "de-
velopment" doctrine, as it was then
called, nor those who were opposed
to it, had the slightest suspicion that
the tendency to variation in living be-
ings, which all admitted as a matter
of fact ; the selective influence of con-
ditions, which no one could deny to
be a matter of fact, when his atten-
tion was drawn to the evidence; and
the occurrence of great geological
changes which also was matter of
fact; could be used as the only nec-
essary postulates of a theory of the
evolution of plants and animals which,
even if not, at once, conqDetent to ex-
jilain all the known facts of biological
science, could not be shown to be in-
consistent with any. So far as biol-
ogy is concerned, the publication of

IN TlIK LAST IIALF-Cr.NTURV.

23

IS of
ooks,
)liysi-
■ ;iml
ivully
[ the
potli.
(loc-

KlJiV,

ieiiccs
.'vcn a
ar ful-
ihosc
10 ob-
A Spe-
^ioii of
" will
[hcwcll
n of
as a
puh-
iiwin
1 the
oiilier
the
" clo-
the n
)p(>.sed
that
nj; be-
lli a tter
f coii-
eny to
alten-
and
llogical

)i

Iter

of

\\ iiec-

)f the

ihich,

to ex-

;ical

ibe in-

biol-

lioii of

O!

the '•Oriq;in of Sprcics," for the first
time, put the iloctriiiu of evolmioti, m
its application to livinj; thini;s, upon
a soniKJ scicutilic foundation. It be-
came an instrument of investigation,
and in no liands did it prove more
brilii.intly profitable than in those of
hirwin iiim^i'lf. His publieaiions on
the elTects of domeslieaiion in plants
ami animals, r)n the inlliieiice of (TOSS- ' Conum-nt on th.it LMcat inulorlakin^

gt'oIo;;ist and tlie physicist, whatever
that ni.iy be.

Kvolution as a philoso])hical doc-
trine applicabli; to ail pluMmmcna,
wlu-tliLT physical or mental, wliclhcr
manifested by material aionis or by
men in society, has been de.dt with
sysli'inatically in the '• Syntlieiio Phi-
losojihy" of Mr. Herbert Spencer.

ft-rtili

i/ation, on Howers as or;:

ins for ' would not be in |)lace here. I men-
clYeclin:jj such fertilization, on insec* j tion it because, so far as 1 Know, it is

the first attempt to deal, on scientific
principles, with modern scientilic facts

and

speculations.

For the " I'liilo-

opine positive

of M. Comte

tivoroiis plants, on the motions of

plants, pointed out the routes of ex-
ploration which have since been fol-

loweil bv hosts of iiujuirers, lo the

great prolit of scienc".

Darwin found the bfoloijical world

a more than siilTi iiMit field for even

his f^real powers, and left the cosnu-

cal part of the doctrine to otheis.

N >: iiri'h has been add-'d to the nel)-

ular hypotlK'sis, since the time of La

place, exce|)t that the attempt to show

(I'^iinst that hvpothesis) that all neb-

11!. e are star clusters, has been nn't

l)y the spectroscopic proof of the f;as

cons condition of some of th<'m.

Moreover, physicists of the present

generation appear now to accept the

secular cooliu'jj of the earth, which is

one of the corollaries of that liyj)oih-

esis. in fad, attempts have been

made, by the help of dedn'tioiis from

the data of physics, to lay down an

approximate limit to the ninnber of

millions of years whieh have elapsed ! In the past iiistory of the universe,

since the earth was habitable by liv- j back to that point, there can be no

ing beini;s. If the conclusions thus j room for chance or disorder. J>ut it

reached should staiul the test of fur- ' is ])ossible to raise the (luestion

ther investigation, they will nndonbt- whether this universe of simplest mat-

edlv be very valuable. Mut, whether | ter and definitely operating enerp;v,

which forms our hvpothetica! starting
point, may not itself be a product of
evolution from a universe of such mat-

Wltll

,'hich Mr. Spencer's system oi philos-
ophy is sometimes compared, though
It professes a similar object, is unlorl-
unately permeaietl by a thoroughly
unscientilic spirit, aiul its author had
no adeip ate acquaintance with the
physical sciences even of his own lime.

The doctrine of evolution, so far as
the present physical cosmos is con-
cerned, postulates th(; fixity of the
rules of operation of the causes of mo-
tion in the material universe, if all
kinils of matter ate modifications of
one Kind, and if all modes of nio:ion
are derived from the same energy, the
orderly evolution of phvsical iiaiiire
out of one substratum ami one energy
im|)lies that the rules of acli(jii of that
energy should be fixed and definite.

true or false, they can have no intlu-

ence upon the dv)Ctrine of evolution

in its application to living organisms.

The occurrence of successive forms ' ter, in wliich the manifestations of

of life ui)on our globe is an historical energy were not definite — in which.

fact, which cannot be disputed ; and
the relation of these successive forms,
as stages of evolution of the same
type, is established in various cases.
'rhe biologist has no ineans of deter-
mining the time over which the proc-
ess of evolution has extended, but ac-
cepts the computation of the physical

fm- example, our laws of motion held
good for some units and not for others,
or for the same units at one time ai. ;
not at another — and which would
therefore be a real epicurean chance-
world ?

For myself, I must confess that [
find the air of this region of specula-

24

THE ADVANCE OK SCIENCE

tion too rarefied for my constitution,
and I am disposed to take refuge in
" ignoramus et ignorabimus."

The execution of my further task,
the indication of the most important
achievements in the several branches
of physical science during the last
fifty years, is embarrassed by the
abundance of the objects of choice ,
and by the difficulty which everyone,
but a specialist in each department,
must find in drawing a due distinction
between discoveries which strike the
imagination by tiieir novelty, or by
their practical influence, and those
unobtrusive but pregnant observa-
tions and experiments in which the
germs of the great things of the future
really lie. Moreover, my limits re-
strict me to little more than a bare
chronicle of the events which I have
to notice.

In physics and chemistry, the old
boundaries of which sciences are lap-
idly becoming effaced, one can hardly
go wrong in ascribing a primary value
to the investigations into the relation
between the solid, liquitl, and gaseous
states of matter on the one hand, and
degrees of pressure and of heat on
the other. Almost all, even the most
refractory, solids have been vaporized
by the intense heat of the electric arc ;
and the most refractory gases have
been forced to assume the liquid, and
even the solid, forms by the combina-
tion of high pressure with intense cold.
It has further been shown that there
is no discontinuity between these
states — that a gas passes into the liq-
uid state through a condition which is
neither one nor the other, and thai a
liquid body becomes solid, or a solid
liquid, by the intermediation of a con-
dition in which it is neither truly solid
nor truly liquid.

Theoretical and experimental in-
vestigations have concurred in the es-
tablishment of the view that a gas is
a body, the particles of which are in
incessant rectilinear motion at high
velocities, colliding with one another
and bounding back when they strike
the walls of the containing vessel ;
and, on this theory, the already ascer-

tained relations of gaseous bodies to
heat and pressure have been shown to
be deducible from mechanical princi-
ples. Immense improvements have
been effected in the means of exhaust-
ing a given space of its gaseous con-
tents , and experimentation on the
phenomena wMch attend the electric
discharge and the action of radiant
heat, within the extremely rarefied
media thus produced, has yielded a
great number of remarkable results,
some of which have been made famil-
iar to the public by the Gieseler tubes
and the radiometer. Already, these
investigations have afforded an unex-
pected insight into the constitution of
matter and its relations with thermal
and electric energy, and they open up
a vast field for future inquiry into
some of the deepest problems of phys-
ics. Other important steps, in the
same direction, have been effected by
investigations into the absorption of
radiant heat proceeding from different
sources by solid, fluid, and gaseous
bodies. And it is a curious example
of the interconnection of the various
branches of physical science, that
some of the results thus obtained have
proved of great importance in meteor-
ology.

The existence of numerous dark
lines, constant in their number and
position in the various regions of the
solar spectrum, was made out by
Fraunhofer in the early part of the
present centur)', but more than forty
years elapsed before their causes were
ascertained and their importance rec-
ognized. Spectroscopy, which then
took its rise, is probably that employ-
ment of physical knowledge, already
won, as a means of further acquisi-
tion, which most impresses the imag-
ination. For it has suddenly and
immensely enlarged our power of over-
coming the obstacles which almost in-
finite minuteness on the one hand, and
almost infinite distance on the other,
have hitherto opposed to the recogni-
tion of the presence and the condition
of matter. One eighteen-millionth of
a grain of sodium in the flame of a
spirit-lamp may be detected by this

IN THE LAST HALF-CENTURY.

25

dark
and
of the
by
f the
forty
were
rec-
then
1 ploy-
ready
quisi-
iinag-
and
1 over-
jst in-
|1, and
nher,
,ogni-
lition
th of <i
iof a
this

instrument; and, at the same time, it
gives trustworthy indications of the
material constitution not only of the
sun, but of the farthest of those fixed
stars and nebulee which afford suffi
cient light to affect the eye or the
photographic plate, of the inquirer.

The mathematical and experimental
elucidation of the phenomena of elec-
tricity, and the study of the relations
of this form of energy with chemical
and thermal, action, had made exten-
sive progress before 1837. But the
determination of the influence of mag-
netism on light, the discovery of dia-
magnetism, cf the influence of crystal-
line structure on magnetism, and the
completion of the mathematical theory
of electricity, all belong to the pres-
ent epoch. To it also appertain the
practical execution and the working
out of the results of the great interna-
tional system of observations on ter-
restrial magnetism, suggested by
Humboldt in 1836 ; and the invention
of instruments of infinite delicacy and
precision for the quantitative deter-
mination of electrical phenomena.
I'he voltaic battery has received
vast improvements ; while the inven-
tion of magneto-electric engines and
of improved means of producing ordi-
nary electricity has provided sources
of electrical energy vastly superior to
any before extant in power, and far
more convenient for use.

It is perhaps this branch of physi-
cal science which may claim the palm
for its practical fruits, no less than for
the aid which it has furnished to the
investigation of other parts of the
field of physical science. The idea j
of the practicability of establishing |
a communication between distant
points, by means of electricity, could
hardly fail to have simmered in the
minds of ingenious men since, well-
nigh a century ago, experimental
proof was given that electric distur-
bances could be propagated through
a wire twelve thousand feet lonji.
Various methods of carrying the sug-
gestion into practice had been car-
ried out with some degree of success ;
but the system of electric telegraphy,

which, at the present time, brings all
parts of the civilized world within a
few minutes of one another, originated
only about the commencenient of the
epoch under consideration. In its
influence on the course of human af-
fairs, this invention takes its place
beside that of gunpowder, which
tended to abolish the physical in-
equalities of fighting men ; of print-
ing, which tended to destroy the effeci
of inequalities in wealth among learn-
ing men ; of steam transport, which
has done the like for traveling men.
All these gifts of science are aids in
the process of leveling up , of remov-
ing the ignorant and baneful preju
dices of nation against nation, provmce
against province, and class aganist
class; of assuring that social order
which is the foundation of progress,
which has redeemed Europe from
barbarism, and against which one is
glad to think that those who, in our
time, are employing themselves in
fanning the embers of ancient wrong,
in setting class against class, and in
trying to tear asunder the existing
bonds of unity, are undertaking a fu-
tile struggle. Ti^e telephone is only
second in practical importance to the
electric telegraph. Invented, as it
were, only the other daj', it has al-
ready taken its place as an appliance
of daily life. Sixty years ago the ex
traction of metals from their solu-
tions, by the electric current, was
simply a highly interesting scientific
fact. At the present day, the galva-
no-plastic art is a great industry ;
and, in combination with photogra-
phy, promises to be of endless service
in the arts. Electric lighting is an-
other great gift of science to civiliza-
tion, the practical effects of which
have not yet been fully developed,
largely on account of its cost. But
those whose memories go back to the
tinder-box period, and recollect the
cost of the first lucifer matches, will
not despair of the results of the appli-
cation of science and ingenuity to the
cheap production of anything for
which there is a large demand.

The influence of the progress of

26

THE ADVANCE OF SCIENCE

electrical knowledge and invention
upon that of investigation in other
fields of science is highly remarkable.
The combination of electrical with
mechanical contrivances has produced
instruments by which, not only may
extremely small intervals of time be
exactly measured, but the varying
rapidity of movements, which take
place in such intervals and appear to
the ordinary sense instantaneous, is
recorded. The duration of the wink
ing ot an eye is a proverbial expres-
sion for an instantaneous action ; but,
by the help of the revolving cylinder
and the electrical marking- appara-
tus, it is possible to obtain a graphic
record of such an action, m wliicli, if
it endures a second, that second shall
be subdivided into a hundred, or a
thousand, equal parts, and the state
of the action at each hundredth, or
thousandth, of a second exhibited.
In fact, these instruments may be
said to be time-microscopes. Such
ajipliances have not only effected a
levolution in physiology, by the power
of analyzing the piienomena of mus
cular and nervous activity which they
have conferred, but they have fur-
nished new methods of measuring the
rate of movement of projectiles to
the artillerist. Again, the micro-
phone, which reiulers the minutest
movements audible, and which ena-
bles a listener to hear the footfall of
a lly, has equi])ped the sense of hear-
ing with the means of entering al-
most as deeply into the penetralia
of nature, as does the sense of sight.

That light exerts a remarkable in-
fluence in bringing about certain
chemical coinl)inations and decomiw-
sitions was well known lifty years
ago, and various more or less sue-
ctssful attempts to produce jierma-
iiL'iit pictures, bv the help of that
knowledge, had already been made.
It was not till 1839, iiowever, that
practical success was obtained ; but
the " daguerreotypes " were both cum-
brous and costly, and ])Iiotograpln'
would never have attained ils iJiesent
important development had not the

paper and glass for the silvered plates
then in use. It is not my affair to
dwell upon the practical apjilication
of the photography of the jMesent
day, but it is germane to my purpose
to remark that it has furnished a
most valuable accessory to the meth-
ods of recording motions and lapse of
time already in existence. In the
hands of the astronomer and the
meteorologist, it has yielded means
of registering terrestrial, solar, ])Iane-
tary, and stellar phenomena, indepen-
dent ot the sources of error attendant
on ordinary observation ; in the
hands of the physicist, not only does
It record spectrf)scopic phenomena
with unsurpassable ease and precis-
ion, but It has revealed the existence
of rays iiavmg powerful chemical
energy, or beyond the visible limits
of either end of the spectrum ; while,
to the naturalist, it furnishes the
means by which the forms of many
highly complicated objects mav be
represented, without that possibri'y
of error which is inherent in the work
of the draughtsman. In fact, in
many cases, the stern impartiality of
photography is an objection to its em-
ployment : it makes no distinction
between the important and the un-
important ; and hence photograplis
of dissections, for example, are rarely
so useful as the work of a draughts-
man who is at once accurate and in-
telligent.

Tlie determination of the exist-
ence of a new planet, Neptune, fnr
beyond the previously known bounds
of the solar system, by mathematical
deduction from the facts of ]X'rturba-
tion ; and the immediate confirmation
i of that determination, 111 the year
1846, by observers who turned their
i telescopes into the part C)f the heav-
I ens indicated as its place, constitute
I a remarkable testimony of nature to
the validity of the princqiles of the
astronomy of our time. In addition,
so many new asteroids have been
' added to those which were already
\ known to circulate in the place which
theoretically should be occupied by
progress of invention substituted [ a planet, between Mars and Jupiter,

IN THE LAST IIALF-CENTURY.

27

ily of
IS em-
icUon
iin-
;raplis
a rely
u_<;ht.s-
iiul in-

exist-

ihat their number now amounts to
between two and three hundred. I
liave already alluded to the extension
of our knowledge of the nature of the
heavenly bodies by the employment
of spectroscopy. It has not only
•Jirfiwn wonderful light upon the phy-
.sic;d and chemical conslilr.tion of the
sun, fixed stars, and nebula-, and
comets, but it holds out a prospect of
obiaining definite cvitlence as to tiie
nature of our so-called elementary
bodies.

The application of liie generaliza-
tions of ihermotics to the problem of
the duration of the earth, and of de-
ductions from tidal phenomena to the
determination of the length of the day
and of the time of revolution of the
moon, in pastei)orhs of the history of
tiie universe ; and the demonstration
of the comjjetency of the great secu-
lar changes, known under the general
name of the precession of the ecjui-
noxes, to cause corresponding modifi-
catif)ns in the climate of the two liemi-
spheres of our globe, have brought
aslron.)my in;o intimate relation with
geologv. Geology, in fact, proves
that, in t!ie course of the {)ast history
of tiie earth, the climatic conditions
of the sain J region have been widely
ditTerent, and seeks the explanation
of ihis important truth from the sister
s.:iences. 'I'lie facts that, in the
middle of the Tertiary c]K)ch, ever-
green trees abounded within the arc-
tic circle ; and that, in the long subse-
quent Q :aternary e|:)och, an arctic
climate, with its ae;:ompaniment of
gigintic glaciers, obtained in the
north-.'rn hemisphere, as far south as
Svitzeil i:id and (Central Viance, are
as well established as any truths of the
science

liiit, whether the explanation

of these extreme variations in them

temneratnre o

n<

rrth

;"reat par

rt of tl

can

le

ern lieiuispliere is to be sought

in tiie concomitant changes in the dis-
tiibution of land and water surfaces

of which

geologv aitords evidence, or

111 astronomual conditions, sucli as

those to which I I

lave

referred, is a

question which must await its answer
from the science of the future.

Turning now to the great stops in
that vast progress wiiich the bijlogi-
cal sciences have made since 1037, we
are met, on the tlireshokl of our
epoch, wi'.h perhaps the greatest of
all — namely, the promulgation by
Schwann, in 1839, of the generaliza-
tion known as the "cell theory," lliu
application and extension of which by
a host of subsequent investigators has
revolutionized niori)hology, develo])-
ment and physiology. Thanks to the
immense series of labors thus inau-
gurated, the following inndamenlal
truths have been established.

All living bodies contain sulistances
of closely similar phvsical and chemi-
cal composition, which constitute the
physical ba^is of life, known as pro
toi^lasm. So far as our present
knowledge goes, this takes its origin
only from pre-existing i)rotopiasm.

All complex living Ijodies consist,
at one pcriotl of their existence, of an
aggregate of minute portions of such
substance, of similar structure, called
cells, e.ich cell having its own life in-
dependent of the others, though in-
lluenced by them.

All the morphological characters of
animals and plants are the results of
the mode of multiplication, growili,
and structural metamorphosis of these
cells, considered as morphological
units.

All the physiological actixities of
animals and jjlants — assimilation, se-
cretion, excretion, motion, generation
— are the expression of ilu- activities
of the cells considered as physiologi-
cal units. Kach individual, among
the higher animals and plants is a
synth(;sis of millions of subordinate
individualities. Its individuality,
therefore, is tliat of a '■civiuis"in
the ancient sense, or that of the Le-
\iathan of I lokbes.

m

Th

'I'liere is no absolute line of de-
arkation between animals and jikinis.

e intimate stru. iir

Hid liie mooes

of change, in the cells of the two are
fundamental I V the same. Moreover,
the higher forms are evolved from
lower, in the cnuise of their develop-
ment, by analogous processes of dlf-

^8

THE ADVANCE OF SCIENCE

ferentiatio*, coalescence, and reduc-
tion in both the vegetable and the
animal worlds.

At the present time, the cell theory,
in consequence of recent investiga-
tions into the structure and metamor-
phosis of the " nucleus," is under-
going a new development of great
significance, which, among other
things, foreshadows the possibility of
the establishment of a physical theory
of heredity, on a safer foundation
than those which Buffon and Darwin
have devised.

The popular belief in abiogenesis,
or the so-called " spontaneous " gen
eration of the lower forms of life,
which was accepted by all the philoso-
phers of antiquity, held its ground
down to the middle of the scenteenth
century. Notwithstanding the fre-
quent citation of the phrase, wrong-
fully attributed to Harvey, " Omne
vivum ex ovo," that great physiolo-
gist believed in spontaneous genera- j
tion as firmly as Aristotle did. And
it was only in the latter part of the
seventeenth century, that Redi, by
simple and well-devised experiments,
demonstrated that, in a great number
of cases of supposed sjiontaneous
generation, the animals which made
their appearance owed their origin to
the ordinary process of reproduction,
and thus shook the ancient doctrine
to its foundations. In the middle of
the eighteenth century, it was revived,
in a new form, by Needham and
liufifon ; but the experiments of
Spallanzani enforced the conclusions
of Redi, and compelled the advocates
of the occurrence of spontaneous gen-
eration to seek evidence for their hy-
pothesis only among the parasites
and the lowest and minutest organ-
isms. It is just fifty years since
Schwann and others proved that,
even with respect to them, the sup-
posed evidence of abiogenesis was
untrustworthy.

During the present epoch, the ques-
tion, wiielher living matter can be
produced in any other way than by
the physiological activity of other liv-
ing matter, has been discussed afresh

with great vigor; and the problem
has been investigated by experimental
methods of a precision and refinement
unknown to previous investigators.
The result is that the evidence in fa-
vor of abiocrenesis has uttcrlv broken
down, in every case which has been
properly tested. So far as the lowest
and minutest organisms are con-
cerned, it has been proved that they
never make their appearance, if those
precautions by which their germs are
certainly excluded are taken. And,
in regard to parasites, every case
which seemed to make for their gen-
eration from the substance of the ani-
mal, or plant, which they infest has
been proved to have a totally differ-
ent significance. Whether not-living
matter may pass, or ever has, under
any conditions, passed into living
matter, without the agency of pre-ex-
isting living matter, necessarily re-
mains an open question ; all that can
be said is that it does not undergo
this metamorphosis under any known
conditions. Those who take a mo-
nistic view of the physical world may
fairly hold abiogenesis as a pious
opinion, supported by analogy and
defended by our ignorance. P5ut, as
matters stand, it is equally justifiable
to regard the physical world as a sort
of dual monarchy. The kingdoms of
living matter and of not-living mat-
ter are under one system of laws,
and there is a perfect freedom of ex-
change and transit from one to the
other. But no claim to biological
nationality is valid except birth.

In the department of anatomy and
development, a host of accurate and
patient inquirers, aided by novel
methods of preparation, which enable
the anatomist to exhaust the details
of visible structure and to reproduce
them with geometrical precision, have
investigated every important group.of
living animals and plants, no less than
the fossil relics of former faunae and
floras. An enormous addition has
thus been made to our knowledge, es-
pecially of the lower forms of life, and
it may be said that morphology, how-
ever inexhaustible in detail, is com-

IN THE LAST HALF-CENTURY.

29

plete in its broad features. Classifi-
cation, which is merely a convenient
summary expression of morphological
facts, has undergone a corresponding
improvement. The breaks which for-
merly separated our groups from one
another, as animals from plants, ver-
tebrates ♦from invertebrates, crypto-
gams from phanerogams, have either
been filled up, or shown to have no
theoretical significance. The ques-
tion of the position of man, as. an ani-
mal, has given rise to much disputa-
tion, with the result of proving that
there is no anatomical or develop-
mental character by which he is more
widely distinguished from the group
of animals most nearly allied to him,
than they are from one another. In
fact, in this particular, the classifi-
cation of Linnceus has been proved to
be more in accordance with the facts
than those of most of his successors.

The study of man, as a genus and
species of the animal world, conduct-
ed with reference to no other consid-
erations than those which would be
admitted by the investigator of any
other form of animal life, has given
rise to a special branch of biology,
known as anthropology, which has
grown with great rapidity. Numer-
ous societies devoted to this portion
of science have sprung up, and the
energy of its devotees has produced
a copious literature. The physical
characters of the various races of men
have been studied with a minuteness
and accuracy heretofore unknown ;
and demonstrative evidence of the
existence of human contemporaries of
the extinct animals of the latest geo-
logical epoch has been obtained.
Physical science has thus been
brought into the closest relation with
history and with archaeology : and
the striking investigations which, dur-
ing our time, have put beyond doubt
the vast antiquity of Babylonian and
Egyptian civilization, are in perfect
harmony with the conclusions of an-
thropology as to the antiquity of the
human species.

Classification is a logical process
which consists in putting together

those things which are like and keep-
ing asunder those which are unlike ;
and a morphological classification, of
course, takes note only of morpho-
logical likeness and unlikeness. So
long, therefore, as our morphological
knowledge was almost wholly confined
to anatomy, the characters of grou])s
were solely anatomical ; but as the
phenomena of embryology were ex-
plored, the likeness and unlikeness of
individual development had to be ta-
ken into account ; and, at present, the
study of ancestral evolution introduces
a new element of likeness and unlike-
ness which is not only eminently de-
serving of recognition, but must ulti-
mately predominate over all others.
A classification which shall represent
the process of ancestral evolution is,
in fact, the end which the labors of
the philosophical taxonomist must
keep in view. But it is an end which
cannot be attained until the progress
of palaeontology has given us far more
insight than we yet possess, into the
historical facts of the case. Much of
the speculative " phylogeny," which
abounds among my present contempo-
raries, reminds me very forcibly of the
speculative morphology, unchecked
by a knowledge of development, which
was rife in my youth. As hypothe-
sis, suggesting inquiry in this or that
direction, it is often extremely useful ;
but, when the product of such spec-
ulation is placed on a level with
those generalizations of morphological
truths which are represented by the
definitions of natural groups, it tends
to confuse fancy with fact and to cre-
ate mere confusion. We are in drtU-
ger of drifting into a new " Natur-Phil-
osophie " worse than the old, because
there is less excuse for it. Boyle did
great service to science by his "Scep-
tical Chemist," and I am inclined
to think that, at the present day, a
"sceptical biologist " might exert an
equally beneficent influence.

Whoso wishes to gain a clear con-
ception of the progress of physiology,
since 1837, will do well to compare
Miiller's " Physiology," which ai>
peared in 1835, and Drapiez's edition

30

THE ADVAN'CE OF SCIENCE

of Richard's " Nouveaux EMments
de IJotanique," publislied in 1837,
with any of the present hand-books
of animal and vegetaljle physiology.
Miiller's work was a masterpiece, un-
surpassed since the time of Haller,
and Richard's book enjoyed a great
reputation at the lime ; but their suc-
cessors transport one into a new
world. 'I'liat which cliaracterizes the
new physiology is that it is permeated
by, and indeed based upon, concep-
tions which, though not wholly alt-
sent, are but dawning on the minds
of* the older writers.

Modern physiology sets forth as
its chief ends : Firstly, the ascertain-

great functions of assimilation, respi-
ration, secretion, distribution of nu-
triment, removal of waste products,
motion, sensation, and reproduction
are performed ; while the operation
of the nervous system, as a regulative
apparatus, which influences the orig-
ination and the transmi*ioii of
manifestations of activity, either with-
in itself or in other organs, lias been
largely elucidated.

1 have pointed out, in an earlier
part of this chapter, that the history
of all branches of science proves that
they must attain a considerable stage
of development before they yield
practical " fruits " ; and this is emi-

ment of the facts and ciMulitions of nently true of physiology. It is only

cell-life in general. Secondly, in
composite organisms, the analysis of
the functions of organs into those of

within the present epoch, that physi-
ology and chemistry have reached
the point at which they could offer a

the cells of which they are composed. I scientific foundation to agriculture;
Thirdly, the explication of the pro- 1 and iL is only within the present
cesses by which this local cell-life is i epoch, that zoology and physiology
directly, or indirectly, controlled and 1 have yielded any very great aid to
brought into relation witk the life of pathology and hygiene. Ikit within
the rest of the cells which compose the ' that tune, they have already rendered

organism

Fourthly, the investiga-
tion of the phenomena of life in gen-
eral, on the assumption that the phy-
sical and chemical processes which
take place in the living body are of
the same order as those which take
place out of it; and that whatever
energy is exerted in producing such
phenomena is derived from the com-
mon stock of energy in the universe.
In the fifth place, modern physiology
investigates the relation between phy-
sical and psychical phenomena, on
the assumption that molecular changes
in definite portions of nervous matter
stand in the relatioi of necessarv
antecedents to definite mental states
and operations. The work which
has been done in each of the direc-
tions here indicated is vast, and the
accumulation of solid knowledge,
which has been effected, is correspond-
ingly great. For the first time in the
history of science, physiologists are
now in the position to say that they
have arrived at clear and distinct,
though by no means complete, con-
ceptions of the manner in which the

highly important services by the ex-
ploration of the phenomena of para-
sitism. Not only have the history of
the animal parasites, such as the
tapeworms and the trichina, which
infest men and animals, with deadly
results, been cleared up by means of
experimental investigations, and effi-
cient modes of prevention deduced
from the data so obtained; but
the terrible agency of the parasitic
fungi and of the infinitesimally minute
microbes, which work far greater
havoc among plants and animals,
has been brought to light. The
"particulate" or "germ" theory of
disease, as it is called, long since
suggested, has obtained a firm founda-
tion, in so far as it has been proved
to be true in respect of sundry epi-
demic disorders. Moreover, it has
theoretically justified prophylactic
measures, such as vaccination, which
formerly rested on a merely empirical
basis ; and it has been extended to
other diseases with excellent results.
Further, just as the discovery of the
cause of scabies proved the absurdity

IN THE LAST IIALF-CENIURV.

31

lion, respi-
ion of nu-

products,
production

operation
. regulative
:s tiie orij;-
ni!«ion of
either witli-
,, has been

an earlier
the history
proves that
:ral>le stage
they yield
this is enii-
It is only
, that physi-
ve reached
ould offer a
agriculture ;
:he present
. physiology
reat aid to
l)Ut within
idy rendered
s "by the ex-
en a of para-
he history of
uch as the
hlnn, which
with deadly
by means of
ms, and effi-
on deduced
ained; but
lie i)arasitic
|nally minute
far greater
d animals,
[light. The
" theory of
long since
Ifinn founda-
een proved
sundry epi-
iver, it has
prophylactic
fation, which
ly empirical
[extended to
ent results,
very of the
e absurdity

of many of the old prescriptions for
the prevention and treatment of tiiat
disease ; so the discovery of the cause
of splenic fever, and other such mala-
dies, has given a new direction to
prophylactic and curative measures
against the worst scourges of human-
ity. Unless the fanaticism of philo-
zoic sentiment overpowers the voice
of phiianthnjpy, and the love of dogs
and cats supersedes that of one's
neighbor, the progress of experimen-
tal physiology and pathology will, in-
dubitably, in course oi time, place
medicine and hygiene upf)n a rational
basis. Two centuries ago Kngland
"was devastated by the plague ; clean-
liness and common-sense were
enough to free us from its ravages.
One century since, sniall-pox was
almost as great a scourge; science,
tiiough working empirically, and al-
most in the dark, lias reduced that
evil to relative iiisignilicance. At
tiie present time, science, working in
tiie light of clear knowledge, has
attacked splenic fever and has beaten
It ; it is attacking hvdrophobia with
no mean j^roinise of success ; sooner
or later it will deal, in the same way,
with diphtheria, typhoid and scarlet
fever. To one who has seen half a
street swept clear of iis children, or
has lost his own by these horrible
l^estilences, passing one's offsprmg
through the fire to Moloch seems
humanity, compared with the pro-
l)osal to deprive them of half tlieir
chances of health and life because
of tiie discomfort to dogs and cats,
rabbits and frogs, which may be in-
volved in the search for means of
guarding them.

An immense extension has been
effected in our knowledge of the dis-
tnbution of plants and animals ; and
the elucidation of the causes which
have brought about that distribution
has been greatly advanced. The
establishment of meteorological ob-
servations by all civilized nations,
has furnished a solid foundation to
climatology; while a growing sense
of the importance of the influence of

a wholesome check to the tendency
to overrate the influence of climate
on distribution. Kxpeditions, such
as that of t'he " Challenger," equi|)ped,
not for geographical ex[)lorati()n and
discovery, but for the purpose of
throwing light on problems of physi-
ca' and biological science, have been
sent out by our own and other (lov-
ernments, and have obtained stores
of information of the greatest value.
P'or the first time we are 111 ]iosscs-
sion of something like precise knowl-
edge of the physical features of the
deep seas, and of the living popula-
tion of the fioor of the ocean. The
careful and exhaustive studv of the
phenomena presented by the accumu-
lations of snow and ice, in polar and
niountamous regions, which has taken
l^lace in our time, has not only re-
vealed to the geologist an agent of
denudation and transport, which lias
slowly and cpiietly produced elTects,
formerly confidently referred to dilu-
vial catastrophes, but it has snggesled
nmv methods of accounting for vari-
ous puz/.ling facts of distribution.

Palaeontology, which treats of the
exinici forms of life and their succes-
sion and distribution upon our globe,
H branch of science which could
hardly be said to exist a century ago,
has undergone a wonderful develop-
ment in our epoch. In some groujjs
of animals and plants, the extinct
representatives, already known, are
more numerous and important than
the living. There can be no doubt
that the existing Fauna and Flora is
but the last term of a long series of
equally numerous contemporary spe-
cies, which have succeeded one an-
I other, bv the slow and gradual substi-
1 tution of species for species, in the
j vast interval of time which haselnps"d
I between the deposition of the earliest
fossiliferous strata and the present
day. There is no reasonable gifumd
for believing that the oldest remains
yet obtained carry us even near the
beginnings of life. The impressive

warnings of Lyell against hasty spec-
ulations, based upon negative evi-
the "struggle for existence" affords dence, have been fully justified ; lime

'tots'

32

THE ADVANCE OF SCIENCE

after time, highly organized types
have been discovered in formations
of an age in which the existence of
such forms of life had been confi-
dently declared to be impossible.
The western territories of the United
States alone have yielded a world of
extinct animal forms, undreamed of
fifty years ago. And, wherever suffi-
ciently numerous series of the remains
of afiy given group, which has en-
dured for 1 long space of time, are
carefully examined, their morpholog-
ical relations are never in discordance
with the requirements of the doctrine
of eTolutioiT, and ofteil afford convinc-
ing evidence of it. At the same time,
it has been shown that certain forms
persist ^wilh very little change, from
the oldest \6 the newest- fossihferous
formations ; and thus show that pro-
gressive development is a contingent,
and not a necessary result, of the
nature of living matter.

Geology is, as it were, the biology
of our planet as a whole. In so far
as It comprises the surface configura
tion and the inner structure of the
earth, it answers to morphology ; in
so far as it studies changes of con-
dition and their causes, it corresponds
with physiology ; m so far as it deals
with the causes which have effected
the progress of the earth from its
earliest to its present state, it forms
part of the general doctrine of evo-
lution. An interesting contrast be-
tween the geology of the present day
and that of half a century ago, is pre-
sented by the complete emancipation
of the modern geologist from the
controlling and perverting influence

tal assumption (which surely is a
dictate of common-sense) that we
ought to exhaust known causes be-
fore seeking for the explanation of
geological phenomena in causes of
which we have no experience. But
geology has advanced to its present
state by working from Lyell's * ax-
iom ; and, to this day, the 'record of
the stratified rocks affords no proof
that the intensity or the rapidity of
the causes of change has ever varied,
between wider limits, than those be-
tween which the operations of nature
have taken place in the youngest
geological epochs.

An incalculable benefit has accrued
to geological science from the accu-
rate and detailed surveys, which have
now been executed by skilled geolo-
gists employed by the governments
of all parts of the civilized world. In
geology, the study of large maps is as
important as it is said to be in poli-
tics ; and sections, on a true scale,
are even more important, in so far as
they are essential to the apprehension
of the extraordinary insignificance of
geological perturbations in relation to
the whole mass of our planet. It
should never be forgotten that what
we call "catastrophes," are, in re-
lation to the earth, changes, the
equivalents of which would be well
represented by the development of a
few pimples, or the scratch of a pin,
on a man's head. Vast regions of
the earth's surface remain geologi-
cally unknown ; but the area already
fairly explored is many times greater
than it was in 1837 ; and, in many
parts of Europe and the United
of theology, all-powerful at the earlier} States, the structure of the superficial
date. As the geologist of my young I crust of the earth has been investi-

days wrote, he had one eye upon fact,
and the other on Genesis ; at present,
he wisely keeps both eyes on fact and
ignores the pentateuchal mythology
altogether. The publication of the
" Principles of Geology " brought
upon its illustrious author a period
of social ostracism ; the instruction
given to our children is based upon
those principles. Whewel! had the
courage to attack Lyell's fundamen-

gated with great minuteness.

The parallel between biology and
geology, which I have drawn, is
further illustrated by the modern

• Perhaps I ought rather to say Buffon's
axiom. For that great naturalist and writer
embodied the principles of sound geology in
a pithy phrase of the Thiorie de la Terre :
" i'our juger de ce qui est arriv^, et mfme
de ce qui arrivera, nous n'avons qu'i exam-
iner ce qui arrive."

IN THE LAST HALF-CENTURY.

33

aX"

iments
d. In
)S is as
n poli-
scale,
) far as
lension
ance of
ition to
let. It
t what
in rt;-
s, llie
e well
nt of a
a pin,
ons of
eolojii-
Iready
realir
many
lUnited
erficial
nvesti-

ry and
Kvn, is
Ifiodern

Juffon's

writer

3logy in

Terre :

It meme

exam-

growth of that branch of the science
known as petrology, which answers
to histology, and has made the mi-
croscope as essential an instrument
to the geological as to the biological
investigator.

The evidence of the importance of
causes now in operation has been
wonderfully enlarged by the study of
ghxcial phenomena; by that of earth-
quakes and volcanoes ; and by that
of the efficacy of heat and cold, wind,
rain, and rivers as agents of denuda-
tion and transport. On the other
hand, the exploration of coral reefs
and of the deposits now taking place
at the bottom of the great oceans,
has proved that, in animal and plant
life, we have agents of reconstruction
of ? potency iiilherto unsuspected.

There is no study better fitted than
that of geology to impress upon men
of general culture that conviction of
the unbroken sequence of the order
of natural phenomena, throughout the
duration of the universe, which is the
great, and perhaps the most impor-
tant, effect of the increase of natural
knowledge.

XL— THE PROGRESS OF SCI-
ENCE FROM 1836 TO 1886.

BY GRANT ALLEN.

Fifty years ago science was still in-
choate. Much had already been done
by the early pioneers. The ground
had been cleared , the building mate-
rials had been in part provided ; the
foundations had been duly and ably
laid ; but the superstructure as yet
had hardly been raised a poor foot or
two above the original level. The
work of the last half century has been
twofold. On one side it has been ac-
cumulative merely : new stocks of
organizable material — the raw bricks
of science — have been laid up, as
before, ready to the call of the mas-
ter mason, but in far greater profu-
sion than by any previous age. On
the other side it has been directive
and architectonic : the endless stores

of fact and inference, thus dug out
and shaped to the hand by the brick-
makers of knowledge in a thousand
fields, have been assiduously built up
by a compact body of higher and
broader intelligences into a single
grand harmonious whole. This last
task forms indeed the great scientific
triumph of our epocli. Ours has
been an age of firm grasp and of wide
vision. It has seen the downfall of
the anthropocentric fallacy. Cosmos
has taken the place of chaos, Iso-
lated facts have been fitted and dove-
tailed into their proper niche ui the
vast mosaic. The particular has
slowly merged into the general, the
general into still higher and deeper
cosmical concepts. We live in aii
epoch of unification, simplification,
correlation, and universality. When
after-ages look back upon our own,
they will recognize that in science its
key-note has been the idea of unity.

Fifty years ago, there were many
separate and distinct sciences, but
hardly any general conception of
science at large as a single rounded
and connected whole. Specialists
rather insisted pertinaciously on the
utter insularity of their own peculiar
and chosen domain. Zoologists \no-
tested with tears in their eyes that
they had nothing to do with chemistry
or with physics; geologists protested
with a shrug of their shoulders
that they had nothing to do with as-
tronomy or with cosmical genesis. It
was a point of honor with each par-
ticular department, indeed, not to
encroach on the territory oif depart-
ments that lay nearest to it. Tres-
passers from the beaten path of the
restricted science were prosecuted
with the utmost rigor of the law.
And within the realm of each separate
study, in like manner, minor truths
stood severely apart from one an-
other : electricity refused to be at one
with magnetism, and magnetism was
hardly on speaking terms with the vol-
taic current. Organization and subor-
dination of part to whole had scarcely
yet begun to be even aimed at. The
sciences were each a huge congeries of

34

THE PROGRKSS OF SCIENCE FROM 1836 TO 1 886.

1^

heterogeneous facts or unassorted
laws: iliev waited the advent of their
unknown Newtons to fall into syste-
matic and organic order.

In the pride of our hearts, we for-
get for tiie nu)st part how very young
science still is. We, who have seen
that infant Hercules strangling ser-
pents almost from its very cradle; we
who have beheld it grow rapidly un-
der our own eyes to virile maturity
and adult robustness of thew and
muscle, we forget how new a power it
iii in the worki, and how feeble and
timid was its tender babyhood in the
first few decades of the present cent-
ury. Among the concrete sciences,
astronomy, the eldest-born, had ad-
vanced furthest when our age was
still young. It had reached the stage
of wide general laws and evolutionary
aspirations. But geology had only
just begun to emerge from (he earliest
plane of puerile hypothesis into the
period of collection and colligation of
facts. Biology, hardly yet known by
any better or truer name than natural
history, consisted mainly of a jumble
of half-classified details. Psychology
still wandered disconsolate in the
misty domain of the abstr.act meta-
physician. The sciences of man, of
language, of societies, of religion, had
not even begun to exist. The an-
tiquity of our race, the natural genesis
of arts and knowledge, the origin
of articulate speech, or of religious
ideas, were scarcely so much as de-
batable questions. Among sciences
of the abstract-concrete class, physics,
unilluminated by the clear light of the
principles of correlation and conserva-
tion of energy, embraced a wide and
ill-digested mass of separate and
wholly unconnected departments.
Light had little enough to do with
heat, and nothing at all to do in any
way with electricity or sound or mo-
tion or magnetism. Chemistry still
remained very much in the condition
of Mrs. Jellaby's cupboard. Every-
where scienc? was tentative and in-
vertebrate, feeling its way on earth
with hesitating steps, trying its wings
in air with tremulous fear, in prepara-

tion for the broader excursions and
wider flights of the last three advent-
urous decades.

The great campaign of the unity
and uniformity of nature was the first
to be fought, and in that campiiign
the earliest decisive battle was wagtil
over the bloody field of geology. In
1837 — to accept a purely arbitrary
dale for the beginning of our e|)(ich —
Lyell had already published his soI>er
and sensible J'rindphs, and the old
doctrine of recunent catastrophes
and periodical cataclysms was totter-
ing to its fall in both hemispheres.
Wholesale destructions of faunas and
floras, wholesale creations of new life-
systems, were felt to be out of keep-
ing with a human age. Drastic cos-
mogonies were going out of fashion.
But even the unifoimitarianism for
which Lyell bravely fought and con-
quered, was in itself but a scrappy
and piecemeal conception side by side
with the wider and far more general
views which fifty years have slowly
brought to us. One has only to open
the Text Book of Geology by Lyell's
far abler modern disciple, Archi-
bald Geikie, in order to see the vast
advance made in our ideas as to the
world's history during the course of
the last half centurv. The science of
the earth's crust no, longer stands
isolated as a study by itself : it fnlls
into its proper place in the hierarchy
of knowledge as the science of the
secondary changes, induced under
the influence of internal forces and
incident energies, on the cooling and
corrugated surface of a once incan-
descent and more extended planet.
I know no better gauge of the widen-
ing which comes over the thoughts of
men with the process of the suns than
to turn from the rndis indigestaque
moles of the Principles and the Elements
(great as they both were in their own
day) to the luminous, lucid, and com-
prehensive arrangement of Geikie's
splendid and systematic Text Book,
The one is an agreeable and able dis-
sertation on a number of isolated and
floating geological facts ; the other is
a masterly and cosmically-minded

TIIK PKOGUESS OF SCIENCE FROM 1 836 TO I886.

35

In

;)l>er

old
plies
ttev-
L-res.

nncl

life-
Leep-

cos-
liion.
1 for

coii-
•appy
; side
neral
lowly

open

ACU'S

(ichi-
; vast
the
se of
ce of
Itands
fills
rchy
If the
nder
and
and
can-
anet.
i den-
ts of
than
taque
ments
own
coin-
kie's
00k,
dis-
and
er is
Inded

account of the phenomena observable
on t!ic oul.T siicU of a coolinj; world,
d;:Iy Cv)'.;si(lcri(l in all their relations,
and ff.'.ly co-ordinated vilh all the
chief i>; ults of all elder and younger
sis'.cr sciences.

Tlie battle of uniformitarianism
itself, however, was but a passing epi
sodc in (lie great evolutionary move-
ment. That movement began along
several distinct lines toward the close
of the previous century, and only at
last consciously recognized its own
informing unity of purpose some
thirty-five years ago. From another
jioinl of view — in connection with its
influence upon thought at large — the
evolutionary crisis has been treated
elsewhere in this review by a philo-
sophic thinker; but in its purely sci-
entific aspect it must also be briefly
considered here, forming, as it does,
the acknowledged mainsi^ring of all
living and active contemporary sci-
ence.

Evolution is not synonymous with
Darwinism. The whole immensely
exceeds the part. Darwinism forms
but a small chapter in the history of a
far vaster and more comprehensive
movement of the human mind. In
its astronomical development evolu-
tion had already formulated itself
with perfect distinctness before the
period with which we have here spe-
cially to deal. The nebular theory of
Kant and Laplace was the first
attempt to withdraw the genesis of
the cosmos from the vicious circle of
metaphysical reasoning, and to ac-
count for it by the continuous action
of physical and natural principles
alone. Our own age has done much
to cast doubt upon the unessential
details of Kant's rough conception,
but, in return, it has made clearer
than ever the fundamental truth of its
central idea — the idea that stars, and
suns, and solar svstems consist of
materials once more diffusely spread
out through space and now aggre-
gated around certain fixed and defi-
nite nuclei by the gravitative force
inherent in their atoms and masses.
As these masses or atoms drew closer

together in union around the common
center, their primitive poicntial crt*
ergy of separation (frankly to employ
the terminology of our own time) was
changed, first mto the kinetic energy
of molar motion in the act of union,
and then into the kinetic energy of
molecular motion 01 heat, as ihey
clashed with one another in bodily
impact around the central core.
Each star, thus produced, forever
gathers m materials from its own out-
lying mass, or from meteoric bodies,
upon its solidifying nucleus, and for-
ever radiates off its store of asso-
ciated energy to the hypothetical sur-
rounding ether. The fullest expres-
sion of this profound cosmical corn
ception has been given in our owr»
time by Tait and Balfour Stewart,
working in part upon the previous re-
sults of Kant, Laplace, the lierschels,
Mayer, Joule, Cleik IMaxwell. aiul
Sir William Thomson. Deeply al-
tered as the nebular hypothesis has
been by the modern doctrine of corre-
lation and conservation of energies,
and by modern researches into the
nature of comets, meteors, and the
sun's envelopes, it still remains in its
ultimate essence the original theory
of Kant and Laplace.

Science has thus, within the period
of our own half-century, exhibited to
us the existing phase of the universe
at large in the light of an episode in
a single infinite and picturable drama,
setting out long since from a definite
beginning, and tending slowly to a
definite end. Other phases, incon-
ceivable to us, may or may not possi-
bly have preceded it; yet others,
equally inconceivable, may or uiay
not possibly follow, lint as realizable
to ourselves, within our existing lim-
itations, the physical universe now
reveals itself as starling in a remote
past from a diffuse and perhaps neb-
ulous condition, in which all the mat-
ter, reduced to a state of extreme
tenuity, occupied immeasurably wide
areas of space, while all the energy
existed only in the potential form as
separation of atoms or molecules;
and the evidence leads us to look foj-

.6

THE TROGRESS OF SCILNCl-: FROM iS^O TO 1886.

ward to a remote future when all the
matter shall he ag^'rcfjalcd into its
narrowest possible limits, while all
the eiieri^y, haviiij; assumed the kinetic
mode, shall have been radiated off into
the ethereal medium. Compared to
tl\e inrmite cosmical vistas thus laid
open before our da/zled eyes, all the
other scientific expansions of our age
shrink into relative narrowness and
iiKsij^'nificanL-e.

As in the cosmos so in the solar
system itsulf, evolutionism has tauj,du
us to rej,'ard our sun, with its atten-
dant planets and their ancillary satel-
lites, all in their several orbits, as
owing their shape, si;ie, relations, and
movements, not to external desi;;n
and deliberate creation, but to the
slow and regular working out of
physical laws, in accordance with
which each has assumed its existing
weight, and bulk, and path, and
position.

Geology here takes up the evolu-
tionary parable, and, accepting on
trust from astronomy the earth itself
as a cooling sjiheroid of incandescent
matter, it has traced out the various
steps by which the crust assumed its
present form, and the continents and
oceans their present distribution.
Lyell here set on foot the evolution-
ary impulse. The researches of
Scrope, Judd, and others into vol-
canic and hypogene action, and the
long observations of geologists every-
where on the effects of air, rain, ice,
livers, lakes, and oceans, have re-
sulted in putting dynamical geology
on a firm basis of ascertained fact.
The heated interior has been shown
almost with certainty to consist of a
rigid and solid mass, incandescent,
hut reduced to solidity under the
enormous pressure of superincumbent
rocks and oceans. The age of the
earth has been approximately meas-
ured, at least by plausible guesswork ;
and the history of its component
parts has been largely reconstructed.
Structural and stratigraphical geology
hare reached a high pitch of ac-
curacy. It is beginning to be possi-
ble, by convergence of evidences, as

the American geologists have shown,
and as CJeikie has exemplilicd, to re-
write in part the history of continents
and oceans, and to realize each great
land-mass as an organic whole, grad-
ually evolved in a ck-finite direction
and growing from age to a>;c by reg-
ular accretions. VN'lnre the old school
saw cataclysms and miracles, vast
submergences and sudden elevations,
the new school sees slow develo|>-
ment and substantial continuity
throughout enormous periods of sinh
ilar activity.

It would be itnpossible to pass over
in silence, in however brief a r/s//m/,
the special history of the glacial
epoch theory — a theory referring in-
deed only to a single episode in the
life of our planet, but fraught with
such immense consequences to plants
and animals, and toman in particular,
that it rises into very high importance
among the scientific discoveries of
our own era. Demonstration of the
fact that the recent peiitxl was pre-
ceded by a long reign rf ice and
snow, in the northern and southern
hemispheres alike, we owe mainly to
the fiery and magnetic genius of
Agassiz ; and the proof that this gla-
cial period had many phases of hotter
and colder minor spells has been
worked up in marvelous detail by
James Geikie and other able c( a<i-
jutors. Its theoretic explanation, its
probable causes, and its alternation
in the northern and southern hemi
spheres by turns, have been ade-
quately set forth by Croll m a pro-
foundly learned and plausible hy-
pothesis. Upon the glacial epoch de-
pend so many peculiarities in the
distribution of plant and animal forms
at the present day that it has come to
assume a quite exceptional importance
among late geological and biological
theories. Standing at the very thresh-
old of the recent period, the great
ice age forms the fixed date from
which everything in modern Europe
and America begins — it is the real
flood which stands to the true story
of our continent and our race in the
same relation as the Noachian deluge

THE i'UO(;ki:ss ov sciknck kkom 1836 to 1886.

37

stood to the imagined or tradilional
world of our prc-scienlific aiircstors.
Modern history bejjins with the gla-
cial epocli.

The science of life has been even
more profouiully affected by the evo-
lutionary impulse than the concrete
sciences of inor<;anic totals. In 1837
biolo;^y as such hardly existed ; zool-
ogy and botany, its separate compo-
nents, were still almost wholly con«
cerned with minute questions of clas-
sification ; "vital force" and odicr
unimaginable metaphysical entities
were the sole explanations curremlv
olTered of all the ])hennmena of plant
and animal life. IJiit Charles Darwin
had then just returned from the cruise
of the BcaglCy and was revolving slowly
in his own mind the observations and
ideas which blossomed out at last in-
to the Orif^in of Species. The germs
of evolutionism were already in the
air. Lamarck's crude speculations
had aroused the attention of all the
best biological intellects of the era.
Hefore long Chambers |)ublished the
Vesti}:^es of Crealion,an(\ Herbert Spen-
cer was hard at work upon the ground-
work of the System of Syntlietic J'/ti-
losophy, 'I'he palajontological work
of Agassiz, Barraude, Owen and
others, and the general advance in
knowledge of comparative anatomy
and embryology, paved the way for
the triumph of the new ideas ; while
simultaneously the dry bones of bot-
any were being kindled into life by a
younger school of workers in many
French and German gardens and lab-
oratories. With the appearance of
the Origin of Species in 1859, the new
departure definitely began. In twen-
ty years the whole world was convert-
ed en bloc. Evolution on the organic
side has been chiefly expounded in
England by Darwin, Huxley, Spencer,
and Wallace ; and on the whole,
though of world-wide acceptance,, it
has been a peculiarly Pmglish move-
ment. Hitherto, indeed, we Ikitons
have been remarkable as the pro-
pounders of the deepest and widest
scientific generalizations : it is only
of late years that our bookish educa-

tors of the new school have conceived
the noble anibition of turning us all
into imitation (lermans. >

Life thus falls into its proper place
in the scheme of things as due essen-
tiallv to the secondarv action of radi-
ated solar energy, intercepted on the
moist outer crust of a cooling and
evolving planet. Its various forms
have been gradually produc«jd, mainly
by the action of natural selection or
survival of the fittest on the immi-nse
number of separate individuals eject-
ed from time to time by pre-existing
organisms. How the first organisms
came to exist at all we can as yet only
conjecture ; to feeble and unimagina-
tive minds the difficulty of such a con-
jecture seems grotesijuely exagger-
ated ; but granting the existence of a
prime organism or grouj) of organisms
plus the fact of reproduction willvhe
redity and variations, and the tei.
dency of such reproduction to beget
increase in a geometrical ratio, we
can deduce from these simple ele-
mentary factors the necessary corol-
lary of survival of the fijtest.with all
its far-reaching and manxdous impli-
cations. Our age has discovered for
the first time the cumulative value of
the infinitesimal. "Many a little
makes a mickle;" that was Lyell's
key in geology, that was Darwin's key
in the science of life. Herbert Speii-
cer's Principles of Bio/oj^y most fully
sum up this whole aspect of evolution
as applied to the genesis of organic
beings.

In 1837, the science of man, and
the sciences that gather roimd the
personality of man, had scarcely yet
begun to be dreamt of. l>ut evolu
tionism and geological investigation
have revolutionized our conception of
our own species and of the ]:)lace
which it holds in the hierarciiy of the
universe. At the very beginning of
our fifty years, Boucher de Perthes
was already enthusiastically engaged
in grubbing among the drift of Abbe-
ville for those rudely chipped masses
of raw flint which we now know as
palzeolithic hatchets. Lyell and oth-
ers meanwhile were gradually extend-

38

THE PKOGRESS OF SCIENCE FROM

1 8^,6 TO

1886.

ing their ideas of the age of our race
on earth ; and accumulations of evi-
dence, from bone-caves and loess,
were forcing upon the minds of both
antiquaries and geologists the fact
that man, instead of dating back a
mere irille of six thousand years or
so, was really contemporary with the
mammoth, the cave-bear, and other
extinct quaternary animals. The
mass of proof J thus slowly gathered
together in all parts of the world cul-
minated at last in Lyell's epoch-mak-
ing Antiquity of Man, published three
years after Darwin's Origin of Species.
Cole'nso's once famous work on the
Pentateuch had already dealt a seri-
ous blow from the critical side at the
authenticity and literal truth of the
Mosaic cosmogony. It was the task
of Lyell and his coadjutors, like Evans,
Keller, and Christy and Lartet, to
throw back the origin of our race
from the narrow hmits once assigned
it into a dim past of mimeasurable
antiquity. Boyd Dawkins, James
Geikie, Huxley, Lubbock, Pe Mor-
tillet, and Bourgeois have aided m
elucidating, confirming, and extend-
ing this view, which now ranks as a
proved truth of palacontological and
historical science,

Darwin's Descent of Man, published
some years later, was an equally ep-
och-making book. Lubbock's Frehts-
tpric Times, sent forth in 1865, and
Origin of Cii'ilization in 1870, had
familiarized men's minds with the
idea that man, instead of being " an
archangel ruined '' Jiad really started
|rom the savage condition, and had
gradually raised himself to the higher
levels of art and learning. Tylor's
^arly History of Mankind, followed a
little later by his still more important
work on Primitive Culture, struck the
first note of the new revolution as a[>
plied to the genesis of religious con-
cepts. McLennan's Primitive Mar-
riage directed attention to the early
liature and relations of the tribe and
family. Wallace's essay on the Ori-
gin of Human Races and Huxley's
valuable work on Man's Place in Nat-
ure helped forward the tide of natu-

ralistic explanation. And by the time
that Darwin published his judicial
summing up on the entire question of
man's origin, the jury of scientific
opinion throughout the world had
pretty well considered its verdict on
all the chief questions at issue.

The impetus thus given to the
sciences which specially deal with
man, has been simply incalculable.
Philology has been revolutionized.
Language has told us a new story.
Words, like fossils, have been made
to yield up their implicit secrets.
I'rehistoric archaeology has assumed
a fresh and unexpected importance.
The history of our race, ever since
tertiary times, and throughout the
long secular winters of the glacial
epoch, has been reconstructed for us
from drift and bone-cave, from bar-
row and picture-writing, with singular
ingenuity. Anthropology and sociol-
ogy have acquired the rank of distinct
sciences. The study of institutions has
reached a sudden development under
the hands of Spencer, Tylor, McLen-
nan, Maine, Freeman, Lang, and Bage-
hot. Comparative mytliology and
folklore have asserted their right to a
full hearing. Evolutionism has pen-
etrated all the studies which bear upon
the divisions of human life. Lan-
guage, ethnography, history, law,
ethics, and politics, have all fell the
widening wave of its influence. The
idea of development and affiliation
has been applied to speech, to writing,
to arts, to literature, nay, even to
such a detail as numismatics. Our
entire view of man and his nature has
been reversed and a totally fresh
meaning has been given to the study
of savage manners, arts, and ideas, as
well as to the results of antiquarian
and archaeological inquiry.

In psychology, the evolutionary im-
pulse has mainly manifested itself in
Herbert Spencer, and to a less degree
in Bain, Sully, Romanes, Croom Rob-
ertson, and others of their school.
The development of mind in man and
animal has been traced pari passu
with the development of the maleiial
1 organism.

Instinct has been clcarlv

y

THE PROGRESS OF SCIENCE FROM 1 836 TO 1 886.

39

stinct
IS has
iiider
:Len-
Bage-
and
to a
pen-
upon
Lan-
law,
L the
The
ation
iling,
n to
Our
iC has
fresh
tudy
s, as
arian

ly im-

ilf in
igiee

Rob-
Ihool.
and
hissu
[urial
Lavlv

separated from reason: the working I in this direction. They recognized
of intelligence and of moral feeling I that heat was a mode of motion, and

has been recognized in horse and
dog, in elephant and parrot, in bee
and ant, in snail and spider. The
genesis and differentiation of nervous
systems have been fully worked out.
Here Maiidsley has carried the prac-
tical implications of the new psychol-
ogy into the do»iain of mental pathol-
ogy, and Kerrier has thrown a first
ray of light upon the specific functions
of jjortions of the brain. Galton's
Hcrciiitary Genius and other works
have also profoundly influenced the
thought of the epoch : while Bastian,
Clifford, Jevons, and others have car-
ried the same impulse with marked
success into allied lines of psycholog-
ical research.

But the evolutionary movement as
a whole sums itself up most fullv of
all in the ])erson and writings of Her-
bert Spencer, whose active life almost
exactly covers and coincides with our
half-centurj'. It is to him that we
owe the word evolution itself, and the
ge"°'al concejit of evolution as a
sing, all-pervading natural process.
He, too, has traced it out alone
through all its modes, from sun and
star, to plant and animal and human
product. In his First Frinciplcs, he
has developed the system in its widest
and most abstract general aspects.
In the Principles of Bioloti^y he has ap-
plied it to organic life ; in the Prind-
ph's of Psycholo!^}' \.o mind and habit :
in tlie Principles of Sociology to socie-

Rumford went so far as to observe
that the energy generated by a give?'
amount of hay burnt iu an engine
might be measured against the energy
generated by the same amount of hay
consumed by horses. But to l>r.
Joule, of Manchester, in our own time
is due the first great onward move-
ment, in the discovery and determina-
tion of the mechanical equivalent of
heat. Joule's numerous experiments
on the exact relation between heat
and mechanical energy resulted in
the establishment of a formula of
equivalence in terms of kilogiamme-
tres necessary to raise by one degree
centigrade the temperature of one
kilogramme of water. More popu-
larly put, he showed that the energy
required to raise a weight of one lum
dred pounds through one foot was
equivalent to the amount required to
raise a certain fixed quantity of water
through one degree in temperature.
Starting from this settled point, it
soon became clear to physical think-
ers that every species of energy was
more or less readily convertible into
every other, and that an exact luiiner-
ical equivalence existed between them.
This principle, which first clearly
emerged into the consciousness of
physicists about the middle decades of
the present century, was originally
known under the name of Persistence

of Force, in which form Grove's well-
known little treatise helped largely to
ties, to politics, to religion, and to ! popularize its acceptance. liut as
human activities and products gener- ! time went on, the underlying distinc-
ally. In Spencer, evolutionism finds s tion between force and energv came
its personal avatar: he has been at j to be more definitely realized, and
once its prophet, its priest, its archi- ' the phrase conservation of eneigv be-
tect, and its builder. j gan to supersede the older and erro-

Second only in importance to the 1 neous terminology. The realization
evolutionary movement among the ; of the varying nature of eneigv as po-
scienlific advances of our own day | tential and kinetic helped in the trans-
must be reckoned the establishment ' formation of the prime concept. /\t
of that profound fundamental physi- ' last, under the hands of Clausius,
cal principle, the conservation of ' Helmholtz, Mayer, Clerk Maxwell,
energy. Even before the beginning ' Tait, and Balfour Stewart, the doc-
of our half century, Davy and Rum- ' trine assumed its modern form — that
ford (especially the latter) had caught ' all energies are mutually convertil)le,
faint glimpses of the coining truth ^ and that the sum-lolal of energy, po-

40

THE PROGRESS OF SCIENCE FROM 1 836 TO 1 886.

teniial and kinetic, is a constant quan-
tity throughout the cosmos.

The practical applications of the
doctrine of energy are as yet only in
their infancy. The whole mass of
theoretical science has to be re-written
in accordance with this new and fun-
damental law. The whole field of
applied science has to be developed
and enlarged by the light of this preg-
nane and universal principle. Its im-

that moment, under the fostering care
of Faraday, Daniell, Cooke, Morse,
Arago, Tyndall, Edison, and Thom-
son, electric science became a power
in the world. The whole theory of
electricity as a mode of energy has
since been fully explored and ex-
pounded. A vast field has been
added to science. Units and modes
of absolute measurement have been
invented. The telephone and micro-
phone have been introduced ; sec-
ondary batteries have been formed
and improved ; the dynamo has be-
come a common object of the country ;
and the electric light has grown under
our very eyes into a practical and ex-
tremely dazzling reality. Electricity,

plications are all-pervading. In
astronomy it has profoundly alTected
all our conceptions as to the sun's
heat, the orbits of planets, the nature
of meteors, the past, present, and fu-
ture of the universe. In biology it
has taught us to envisage t"he plant

mainly as a machine in which kinetic ! as we know it, with all its manifold
energy is being transformed into po- useful applications, is almost entirely
tential ; the animal mainly as a ma- a creation of the last half century.
chine in which potential energy is be- In physics the present epoch,
ing transformed back again into though chiefly remarkable for the
kinetic. In meclianics and the me- series of investigations which led up
chanical arts it has produced and is to the discovery of tlie law of conser-
producing immense changes. And in j vation, has also illustrated many
the future it is destined still more j minor principles of the first im-
profoundly to alter our ineclunical | portance. The true theory of heat
ideas and activities : the great revolu- [ and the laws of radiant energy have
tion there is only just beginning ; | been definitely formulated. The un-
another half century is yet needed dulatory theory ot light — a discovery

of the previous quarter century — has
been universally adopted and justified.
Thermo-dynamics have been elevated

fully to develop it

These two great principles — evolu-
tion and the conservation of energy —
form the main bulk of our age's addi-
tion to the world's accunulated stock
of knowledge. But among the sepa-
rate sciences many wontlerful ad-
vances have also been made which

into a great and increasing branch of
science. Sir William Thomson's law
of dissipation of energy has completed
and rounded off the tlieory of conser-
vation. The causes and methods of

cannot be overlooked in the briefest glacier motion have been investigated

retrospect of the half century's gains
To these a few words must next be
devoted.

Amon<r sciences of the n!)stract-

and established. I'liotography has
almost passed through its entire life-
cycle. The pol • "ation of light has
been observed and studied. Spectrum
concrete group electricity had hardly j analysis has come into the front rank
got beyond the stage of an elegant I as an instrument of research. In
amusement at the opening of our short, a greater number of new physi-
epoch. Statical electricity was still cal phenomena have been discovered

the department about which most was
known. Galvanism as y('t stood apart
as a distinct study. Its connection
with magnetism had not long been
proved by the discoveries of Oersted.
In 1837 itself, however, Wheatstone
constructed the first telegraph. From

or old ones interpreted than in the
whole space of previous time put
together.

In chemistry, the advance has been
more in detail than elsewhere. Chem-
ical science alone still remains a
somewhat fragmentary mass of indi-

THE PROGRESS OF SCIENCE FROM 1 836 TO 1 886.

41

)een
111 e ni-
ls a
lindi-

vidual facts and observations, colli-
gated by minor laws and analogies,
but uniliuminated as yet by the broad
light of any great and all-embracing
general principles. Since Dalton's
atomic theory, indeed, no philosophic
generalization of the very first magni-
tude has been introduced into chemis-
try. But generalizations of the sec-
ond order — vastly interesting to
chemists, and to chemists alone —
have been made in such numbers as
to defy enumeration ; wider concep-
tions have in many ways sprung up ;
the science has assumed a new form ;
and some of the results of spectrum

ful. The invention of the spectro-
scope, and the rapid development of
spectrum analysis, have placed in the
hands of astronomers a uiethod and
an instrument inferior in value only
to the telescope itself. It is not so
long since Comle dogmatically de-
clared we could never know anything
of the chemical composition of the
fixed stars. Scarcely were the words
well out of his mouth when the in-
vention of the spectrosco|)e and its
application to the spectra of incandes-
cent bodies brought the investigation
of the elements in the sun ami stars
well within the reach of human possi-

analysis and of the new chemistry j bility. 'J'he successive res^-arches of
lead to the hope that this science too 1 VVheatstone, Foucaiilt, Secchi, Bun-
is on the eve of arriving at that stage sen, KirchhufT, and Nnrman Lockyer,

of far-reaching fundamental truths
which it is the special function of our
generation to bring about.

Mathematics have also undergone
a new development, scarcely capable
of being rendered comprehensible to
the lay intelligence.

The applications of physical, elec-
trical, and chemical science in the
great mechanical and industrial in-

exactly covering our fifty years, have
at last enabled us to prove almost
with certainty the presence in the
solar envelopes of several inetals
already known in the earth's crust,
such as potassium, sodium, calcium,
iron, nickel, and chromium. So deli-
cate is the spectroscopic test that it
renders possible the detection of so
small a fraction as the two hundied
ventions of our iron age belong else- i millionth part of a grain of sodium,
where, and are already familiar in ' And by revealing bright lines in the
many respects to all of us. Railways j spectrum not previously referable to
slightly antedate the epoch ; the tele- 1 any known body, it has been the
graph is just coeval with it. 'J"he first j means of discovering fiv^e new metals,
submarine cable was in 185 1, the first cctsiuni and rubidium (detected by

transatlantic in 1866. Electro-plating,
the steam-hammer, the Armstrong
gun, the Bessemer process, must not
be forgotten. Other triumphs of ap-

Bunsen), thallium (by Crookes), in-
dium (by Richter), and gallium (by
Lecoq).

Our knowled<re of the sun's consti-

plied science fall more fitly under , tution, in particular, has advanced

another heailing. with extraordinary rapidity during the

Among the concrete sciences, period here nnder review. Even

thirty years ago we knew little of the
central orb of our svstem save a few
naked mathematical facts as to his
diameter, his density, his attractive
power, and the spots on his surface.
Thirty years of constant investigation
have now enabled us to picture to our-
selves with tolerable accuracy the ac-
tual state of the sun's fiery exterior.
The new era began with Schwabe's
discovery of the periodicity of the
sun's spots in 185 1. The develop-
ment of spectroscopic analysis be-

astronomy has made vast advances
during the past half century. Lord
Rosse's great telescope was set up ai
Parsontown in 1844. Two years
later, Leverrier and Adams made
their curious simultaneous discovery
of the planet Neptune. But it is not
so much in new lists of suns or satel-
lites— though the name of these alone
has, indeed, been legion — as in the
fresh light cast upon the nature and
constitution of olc^r ones, that our
age has been most singularly success-

'IL,

42

THE PROGRESS OF SCIENCE FROM 1 836 TO 1 886.

tween 1854 and 1870 followed hard
on this first impulse. Since i860
eclipses have yielded us valuable re-
sults. Observations on transits of
Venus have largely corrected a seri-
ous error in our calculations of our
primary's distance from the earth.
Janssen and Lockyer have taught us
how to observe at any time, by means
of the spectroscope, phenomena which
were previously observable only dur-
ing moments of total eclipse. Hug-
gins has shown us how to isolate those
marvelous protuberances of incandes-
cent gas which burst forth with explo-
sive violence from tmie to time from
the edge of the photosphere. Tacchi-
ni, Secchi, Young, and others, have
carried out these interesting research-
es to a still higher pitch of certainty
and accuracy ; and the sun's geogra-
phy, so to Si^eak, is to-day no longer
a closed book to mundane observers.
We know our central luminary now
as a mass of intensely heated gas,
surrounded by a shell of luminous
cloud, the photosphere, formed by tlie
cooling of condensable vapors at the
surface where exposed to the cold of
outef space ; and floating in a chromo-
sphere of incondensable gases (nota-
blv hvdrojjen) left behind bv the for-
niation of the photospheric clouds.
The mysterious corona alone as yet
evades our methods of research.

In the solar system at large, great
advances have been made in the de-
tails of planetary astronomy. The
differences in kind between the older
group of interior planets, now in their
cold and solid age, and the younger
group of exterior planets, still in their
boisterous and fiery youth, has been
well ascertained. ThI;-, truth — of so
much interest from the evolutionary
point of view — has b'>en especially
worked out by R. A. Proctor. Nas-
mytli's observations on our own dead
satellite, the moon, have given us a
graphic and appalling picture of a
worn-out world in its last stage of life-
less, waterless, and airless decrepi-
tude. New moons have been added
to Mars, and several tedious ndditions
have been made by minutely obstet-

rical astronomers to the already in-
conveniently large family of the minor
planets. AH our fresh knowledge of
Jupiter and Saturn, those tinbulent
and volcanic orbs, has helped to im-
press the general soundness of the
evolutionary hypothesis ; while the in-
creasingly important study of meteors
and comets has brought us close to the
very threshold of the great ultimate
mystery of star-genesis and world-
forming. The extreme tenuity of the
mass of comets, the inconceivable
rarity of the matter composing their
gaseous tails, the ci rious phenomena
of their instantant ous reversal on
passing their peri lelion, the proof
that their light is partly reflected and
partly direct, the s^Dectroscopic deter-
mination of their composition, the
discovery of the essentially planetary
nature of meteor-streams, and the rec-
ognition of their vast numbers swarm-
ing through space, are among the most
striking novelties of the last half cent-
ury in this direction.

In sidereal astronomy, besides the
mere mechanical increase of mapping,
the chief advances have been made
in observations upon double stars,
spectroscopic analysis of fixed stars
and of nebiilai, and consecjuent proof
of the fact that truly i Tesolvable neb-
ulfE do really exist, the gaseous raw
material of future stars and solar sys-
tems. It must be added that within
the half century the hypothetical ether
has amply vindicated its novel claim
to take its place as a mysterious entity
side by side with matter and energy
among the ultimate components of
the objective universe.

In geology the chief theoretical ad-
vances have been made by the recog-
nition of the cosmical aspects of the
earth's history ; its relations to nebula,
sun, and meteor ; the importance of
eccentricity and precession of the
equinoxes, and the possible results of
ancient changes in its rates of motion,
tides, and so forth. Dynamical geol-
ogy has made vast strides, especially
in the investigation of volcanic phe-

nnmena. mountain

•bu

ilflni":, an

d tl

le

birth and growth of i:ilands and con-

THE PROGRESS OF SCIENCfi FROM 1 836 TO 1886.

43

lars,
Slavs
roof
neb-
raw
sys-
^ith'.n
ether
claim
nitity
lergy
ts of

il ad-
-cog-
the
"Ibula,
le of
the
Its of
]lion,
ifenl-
lially
jplie-
the
I con-

tinents. The science of earth-sculp-
ture has been developed from the
very beginning. Straligraphical geol-
ogy has been largely improved. And
in palreontology an immense number
of the most striking and interesting
of fossil forms have been brought to
light. Among them may be specially
mentioned those which have proved
of critical importance as evidences of
the truth of organic evolution — the
toothed birds of the Western Ameri-
can cretaceous deposits, the lizard-
like bird or bird-like feathered lizard
of the Solenhofen slates, Marsh's re-
markable series of ancestral horses,
Cope's beautiful reconstruction of the
fossil progenitors of existing camels.
Monkeys certainly, anthropoid apes
clearly, man dnuijtfully, have been de-
tectecl in the fossil state. India, Aus-
tralia, Canada, tiie United Slates have
been explored and surveyed, geologi-
cally and palaiontologically ; and the
exploitation of the far West in partic-
ular has not only added immensely to
our knowledge of life in past times,
but lias also revolutionized our con-
ceptions as to die gradual growth and
devL''opine!it of continental areas, and
the occasional vast sjale of volcanic
phenomena. Tiie permanence of all
great continents and oceans is now a
proved truth of geolo-4,y. It has been
reinforced and extended from a totally
ditYvrent point of view by Alfred Rus-
sel Wallace, whose masterly works on
the Gi.'Oi; rap Ideal Distribution nf Ani-
mals and on Is/an I Lift: have immense
geological as well as biological iinpli-
cati'jus.

In pure biology, besides the grand
advance implied in the establishment
of the doctrine of descent with modi-
fication, and its subsidiary principles
of survival of the fittest and sexual
selection, profotmdly important minor
results have also been attained in
many directions. Embryology in the
hands of Von Baer and his success-
ors, notably Kowalevsky and Balfour,
has acquired prime importance as an
instrument of geological research.
(^onin;)r itive osteoloi^jv in the hands
of Owen, Iluxley, Gaudry, and Busk,

has given us new Views 6f the rela-
tionships between vertebrate animals.
The pedigree of fishes, anipliil)ians,
reptiles, birds, and mammals, has been
worked out with a considerable de-
gree of fulness from the hints suj>
plied us by the amphioxus, the ascid-
ian larva, the facts of embryology,
and the numerous recent discoveries
of intermediate or arrested organisms,
recent and extinct. Invertebrate
zoology has been rescued from chaos
and partially reduced to temporary
and uncertain order. Botany, at
once the dullest and the most alluring
of all sciences, has been redeemed
from the vicious circle of mere classi-
ficatory schemes, and vivified by the
fresh and quickening breath of the
evolutionary spirit. The new mor-
phology has revolutionized our ideas
of vegetal homologies ; the new phy-
siology has fastened all its attention
on the adaptations of the plant to its
natural environment. The fascinating
study of tht mutual relations between
flower and nsect in particular, set on
foot before the dawn of our epoch by
Christian Sprengel, but re-introduced
to notice in recent times by Darwin's
works on orchids and on cross fertil-
ization, has been followed out with ar-
dor to marvelous results by Her-
mann Miiller, Axel, Delpino, Hilde-
brand, Lubbock, Ogle and others.
Heer and Saporia have worked out in
great detail the development of sev-
eral fossil floras. Last of all, Her-
bert Spencer has cast the dry light of
his great organizing and generalizing
intelligence on the problems of he-
redity, genesis, variation, individuality,
j and the laws of multiplication. Fifty
years ago biology was a mighty maze
I wholly without a plan. To-day the
I clue has been found to all its main
avenues, and even the keys of its
I minor recesses are for the most part
! well within reach of the enlightened
j observer.

j Even the actual gains in the num-
i ber of new organisms addeil to our
! lists during the last half century are
in tlitunselves ast'inisliin;; ; and,
\ strange to say, the species that bear

44

THE PROGRESS OF SCIENCE FROM 1836 TO 1 886.

it

most closely upon the theory of or-
ganic evolution are almost all of them
quite recent additions to our stock of
knowledge. The gorilla appeared on
the scene at the critical moment for
the Descent of Man, Just on the j
stroke vviicn they were most needed, 1
connecting links, both fossil and liv-
ing, turned up in abundance between
fish and amphibians, amphibians and
reptiles, reptiles and birds, birds
and mammals, and all of these
together in a perfect network of!
curious cross-relationships. Lizards •
that were almost crows, nmrsupials
that were almost ostriches, insec- j
tivores that were almost bats, rodents
that were almost monkeys, have come '
■ir the very nick of time to prove the j
i I'lh of descent with modification.
/^K-'ong he most interestnig of these j
strn ig'; coincidences are such epi-
sodes T.:- the vliscovery in the rivers of
Queens! a;:''! j^ that strange lung-bear-
a\r nnd ;^)i!-L!e.ithing fish, the bar-
r.inuinda, orly • s-\\\\ before in the
fossil form as a long extinct species,
but m whose anatomical structure
Giinther has discerned the missing
link between the antique ganoid type
of fishes on the one hand, and the
mudfish and salamandroid amphibi-
ans on the other.

In the practical applications of bio-
logical and physiological science to
the wants and diseases of human life,
two at least deserve mention here. An-
aisthetics are almost entirely a growth
of our half century : chloroform was
first employed in operations by Simp-
son in 1847, '^"^ ^^^^ "^'^ ^f other simi-
lar agents is still more recent. Again,
the discoverv that zvmoiic diseases in
men and animals are due to the mul-
tiplication within the body of very
minute organisms, known as micro-
bes, bacteria, or bacilli, now promises
to revolutionize medical science.
Their connection with decomposition
was still earlier detected. The names
of Pasteur, Tyndall, and Koch are
specially identified with researches
into the nature of these tiny morbid
organisms and the best means of pre-

venting or neutralizing their attacks,
either on living or dead matter.

In marvelous contrast to the frag-
mentary and disjunctive science of
fifty years ago, modern science at the
present day offers us the spectacle of
a simple, unified, and comprehensible
cosmos, consisting everywhere of the
same prime elements, drawn together
everywhere by the same great foices,
animated everywhere by the same
constant and indestructible energies,
evolving everywhere along the same
lines ill accordance with the self-same
underlying principles. It shows us
the community of ultimate material in
sun and star, in nebula and meteor,
in earth and air and planet and
comet. It shows us identical metals
and gases in fiery photosphere and in
electrically-heated matter in our own
laboratories. It shows us atoms of
hydiogene or of sodium pulsating
rhythmically with like oscillations
in star-cloud or sun-cloud, and
in London or Berlin. It exhibits
to our eyes or to our scientific im-
agination a picture of the universe
as a single whole, a picture of its evo-
lution as a continuous process. One
type of matter diffused throughout
space ; one gravitative attraction
binding it together firmly in all its
parts, one multiform energy quiver-
ing through its molecules or travers-
ing its ether, in many disguises of
light, and heat, and sound, and e'ec-
tricity. It unfolds for us in vague
hints the past of the universe as a
difTuse mass of homogeneous matter,
rolling in upon its local centers by
gravitative force, and yielding up its
primitive energy of separation as light
and heat to the ethereal medium. It
suggests to us this primitive energy of
separation as the probable source of
such light and heat in suns and stars
as we now know them. It posits for
us our own planet as an orb gathered
in from the original cloud-mass, witii
outer surface cooled and corrugated,
and with two great envelopes, atmos-
pheric and oceanic, gaseous and liq-

uid, still floating or precipitated

THE PROGRESS OF SCIENCE FROM 1 836 TO 1886.

45

around its denser core. It teaches
us how the hard crust of the hot qeii
tral mass has been uplifted here into
elevated table-land, or depressed
there into hollow ocean-bed. By the
aid of its newest instrument, meteor-
ology, it lets us see how incident solar
ciiL'r^ijy, raising clouds and causing
rainfall, with its attendant phenomena
of drainage and rivers, has carved
and duiiuded the upheaved masses
into infinite variety of hill and valley.
It shows us how sedimtiiit, thus
gathered by streams on the bed of
the sea, is pushed up once more by
volcanic power or lateral pressure in-
to alpine chains and massive conti-
nents, and how these in their turn
have been worn down by the long-
continued bombardment of aqueous
or aerial action into mere stumps or
relics of their primitive magnitude.
It puts before us life as an ultimate
result of solar energy falling on the
watery and gaseous shell of such a
solidified planet. It suggests to us
how light, acting chemically on the
leaves or fronds or cells of the green
herb, stores up in them carbohy-
drates, rich in potential energy, which
animals afterwards use up as food, or
man utilizes as coal in his grates and
his locomotives. It exhibits to us the
animal organism as essentially a food-
engine in whose recesses solar energy,

stored as potential by the plant, is
once more let loose by slow combn.s-
tion in the kinetic form as heat and
motion. It enables us to regard the
body as a machine in which stomach
and lungs stand for furnace and
boiler, the muscles for cylinder, pis-
ton, and wheels, and the nervous sys-
tem for an automatic valve-gtar. It
traces for us from small beginnings
the gradual growth of limb and organ,
of flower, fruit, and seed, of st-nse
and ijitellect. With the simj)le key
of survival of the fittest it unlocks
for us the secret of organic diversity
and universal adaptation. It recon-
structs for us from obscure half-hints
the origin of man ; the earliest stages
of human history ; the rise of speech,
of arts, of societies, of religion. It
unifies and organizes all our concepts
of the whole consistent system of
nature, and sets before our eyes the
comprehensive and glorious idea of a
cosmos which is one and the same
throughout, in sun and star and world
and atom, in light and heat and life
and mechanism, in herb and tree and
man and animal, in body, soul, and
spirit, mind and matter. Almost all
that is most vital and essential in
this conception of our illimitable
dwelling-place, the last half century
has built up for us unaided.

CONTENTS.

PACB

I. The Advance of Science in the Last Hatt-century.
II. The Progress of Science from 1836 to t886

33

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The JAhrai'if is published monthly. Price to subscribers $1,S0
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* *

J. FITZGERALD, PVBLlSnER,

24 East Fourth Street.

No. 1. lilsht Sricnre Tor I.clMiire
lloum : A siTics (if Kiimiliar Kssays on Scrcii-
tilic Sul)jc(ns. Hy Rii mauu A. I'mn lou, K.R.A.S.
Contents (in part) :— Tlic Karth a Magnet ; the
Secret of the North Hole; Our Chief Timepiece
I.osinfj Time; Tornadoes; Influence of Marriage
on the Death Rale ; Squarln^; thi' Circle • the Use-
fulness of Earthquakes ; the Forcing Powor of
Rain, etc., etc.

No. 3. The ForiiiM of Water in Clouds and
Rivers, Ice and (ilaciers. By John Tv.nij.\ll,
I.I..D., F.R.S. ulluslrat(td).

Contents (in part) :— Oceanic Distillation ; Archi-
tecture of Snow ; The Motion of Glaciers; Icicles;
ICrratic Blocks; Tropical Rains; Atomic Holes;
1-iirthof a Crevasse ; Moraine Ridjjes, etc., etc., etc.

No. 3. PliyNi<-N and PollticH: -An Appli-
cation of the I'liucijiks of Natural Selection and
Jlcredityto Political Society. By VV.m.tkk Bai;k-
HOT, Author of " The English Constitution,"
etc.
Contents; — The Preliminary Age ; the Use of

Conflict ; Nation Making ; the Age of Discussion ;

Veritiable Progress Politically Considered.

No. 1. Kvldciieo aN to niuii'MPIaro in
Nature. By Thom.vs Hu.\i.iiv, F.R.S. (,i"iJS-
trated).

Contents:— The Natural History of the Manlike
Apes; The Relations of Man to the Lower Ani-
mals; Fossil Remains of Man.

No. 5. KdiK'atlon : Intellectual, ITIo^al
and Pliyctlcal. By Hi:iau:i<r Siknckk.
Contents :— What Knowledge is of Most Worth?
Intellectual Education ; Moral Education ; Physi-
cal Education.

No. 6. Town Ocolos:|r. By the Rev.

CnARi.ES KiNc.sLKV, F.R.S., Canon of Chester.

Contents :— The Soil of the Field ; the Pebbles
In the Street ; the Stones in the Wall ; the Coal in
the Fire ; the Lime in the Mortar ; the Slates on
the Roof.

No. 7. The Connervatlon of Encrgsr.

By Balfour Stkwart, F.R.S. illustrated).

Contents ;— What is Energy ? Mechanical En-
ergy and its Change into Heat ; The Forces and
Energies of Nature ; Transmutations of Energy ;
the Dissipation of Energy; the Position of Life;
Correlation of Nervous and Mental Forces.

No. 8. fhe Study of lianguages brought
back to its true Principles. By C. Makcei..
Contents :— Subdivision and Order of Study;

the Art of Reading; the Art of Hearing; the Art

of Speaking ; the Art of Writing; Mental Culture ;

Routine.

No. 0. The Data of Ethic*. By Herbert

Spencer.

Contents ;— Conduct in General ; Evolution of
Conduct ; Good and Bad Conduct ; Ways of Judg-

ing Conduct ; The Physical View ; The Rinlof^fical
View ; the Psychological View ; the Sociological
View; Criticisms and K.xplanations ; Relativity of
Pains and Pleasures; Egoism rs. Altruism; Al-
truism 7'j. Egoism; Trial and Compri^mise: Coa>
ciliution ; Absolute Ethics and Relative Ltbica;
the Scope of Ethics.

No. 10. The Theory of Sound in its Rela-
tion to niUMlr. By PKOI . PlKlKO Bl.ASI'.KNA, ol

the Royal University of Rome (illustrated).

Contents (in part) :- Periodic .Njovements, vibra-
tion ; Transmission of Sound ; Characteristics of
Sound, and dilYerence between musical sound and
noise; Discords; yu;dily or ti/n/'rf of musical
sounds; Italian and (ierni.m music, etc., etc.

NoM. 11 and I'i. The Nuturallitt on th«
Hlvcr AniuzoiiM: -.\ Kecor^l of AiiventureiL
H.ibits of Animals, Sketches of Brazilian ana
Indian Life, and Aspects of Nature under th«
Equator, during eleven years of Travel. By
Hk.vrv VV'amer Batks, 1''.R.S.
*♦* One of the most charming books of travel in

our language.

No. 13. mind and Body: The Theorienof

their Relation. By Ai.r xa-.hkk Bain, LL.D.,

Professor of Logic in the University of Aber»

deen.

Contents:— The Ouostinn Stated; Conncctio* of
Mind and Body ; tVio (.(miicrtion viewed a.s corre..
spondence or concomitant v^iri.uion ; (leneral Laws
of Alliance of Mind and Body: the Feelings and
will ; the Intellect ; How are Mind and Body
United ? History of the Theories of the Soul.

No. 14. The Wondcrw of the Heavens.

By Camh.i.k Fi.ammakion (illustrated).

Contents (in part):— The Heavens; the Milky
Way; Double, Multiple and Colored Suns ; the
Planets ; the Earth ; Plurality of Inhabited Worlds}
Infinite Space ; Constellations; TlieSun; Comets;
the Moon, etc., etc.

No. i't. liOUgevlty: the Means of Prolong,
ing Life after the Middle Age. By John Gjvkl>«
NEK, M. D.
Contents (in part) :— Is the Duration of Life ia

any way within our power? Physiology of Ad>.

vanced Age ; Heredity ; Established Facts regard'.

ing Longevity, etc., etc.

No. 16. On the Origin of Species; or the

Causes of the Phenomena of Organic Nature: A

Course of Six Lectures. By Thomas H. Hox-

i.EY, F.R.S.

Contents :— Present Condition of Organic Nature;
Past Condition of Organic Nature; Origination of
Organic Beings ; Perpetuation of Living Beings;
Conditions of Existence ; A Critical Examination
of Mr. Darwin's Great Work,

No. 17. Progress : Its liair and Cause}

with other disquisitions. By Hbruukt SfSNCWU

Co:iteBM:- Vrnmretn; the Phtilo'ojnr of L»ii(jh-
ter; OrJKin and hunctlonH of Nfuaic ; tlie Devvloii-
ncnt II)p(itiiL->i< , liiu :jLi(.i.4l (Ji'K^niiiiu } the L'sc
of AnthropomnrphiHin,

•o. 18. LttMoiiM In Elcrtrlcltjr. By

J»HM TVNDAl.l., K.k.S. (lllUHtralC(l).

Contents un pitrtj: The Art of Kxperiincnt ;
Khnrtric Induction; l.khtinliirn'ii Kiuurcs ; Klic-
Uica «nd Non-Electrics; the I.cydcn Jar ; I'liysio-
l«((icat kflcct of the r.lcctric UiicharKU ; Atmoii-
phcrlc Rleetricity, rtc, c-tc.

No. 10. Fain 1 1 III r ICNaayn on Srlouiiflc
Hnkjet'tli. ily Ki' hmh. a. I>i«u r(.K, I'.K.A.S.
C!olitcMU!» :~-()xyKi.n in llie Sun ; Sun spot, Slurm
■nd Kamini- ; New wuyn of McviHurint; the Sun's
l)iHtan«e: Driftinc I.ittht-wavcs ; The new Star
which faded into Star-mist ; Star-Kroupin^.

No. ao. Tlio Honiuneo of Aatrouomy.

Hy R. Kaii>v Mm rh, M.A.

Contents: — The I'laiirts ; AstroloKv ; The Moon ;
the Sun ; the Comets : I.aolace's Nebular ilypcjth-
c«i» ; the Stars; the Ncbulx- ; Appendix.
No. ai. On tlip PliyMloal UamlM of Mi'o.

Hasis of Life ; Scientflic
A I'iecc of Chalk ; (ieoloj;-
; A Liberal EJucation and

With other

I.BV, K.R.S

Contents ; — Physical
Aitiects of Positivism ;
icai Contemporaneity
where to find it.

No. 3!I. MeclnK and Tliinklnff. fiy I'mf.

Wii.i.iAM KiMMiiiN Ci.ii I cH.ii, I'.K.S. lillusiratcd).

Contents;— The Kye and the Itrain ; the Kye and
SeeinK ; the Urain and Thinking; On Houndaries
in General.
No. its. Srlentlllr NoplilMnm t -A Review

of Current 'I'heories t<mceinin>,' Atoms, Apes

and Men. Hy Swii m. Wainkk.mi-, l).\).

Contents:— 'I he RiKln of Search ; Evolution; A
Puerile Hypothesis ; Scientific Levity ; a House of
Cards; Sophisms; Protoplasm; the Three Heifin-
ninffs; the Three Harriers; Atoms; Apes; Men;
Annna Mundi.

No. 34. Popular Sc'Icntlflo Lectures.

By Prof. U. fliii.Miioi 1 / (illiis:raled).

Contents;— Tlie Relation of Optics to I'aintlni,'.
I. Form. a. Shade. ,\. Color. 4. Harmony of
Color ; the Origin of the Planetary System ;
Thought in Medicine ; Academic Freedom in Ger-
man Universities.

No. as. Tlio Origin ot° Natlonw 1— Com-
prisinif two diviKiuiis, viz.: — " ICarly Civiliza-
tions, and " lulinic Altinities." Hy (Ikhki.k
Rawi.in.son. M.A., Camden Professor of Ancient
History in Oxford I'niversity, I^nf^land.
Contents :— Early Civilizations : — Inlrndiiction ;
Antiquityof Civilization in EnRland ; Antiquity of
Civilization at Habylon ; Phienician Civilization ;
Civilizationsof Phrvfjia, Lydia, the Troas, Assyria,
Media, India, etc.; Civilization of' he Hritisli Celts;
Civilization of the Etruscans; Pi-sults of .the In-
quiry. Ethnic Atlinitics ;— Cliief Jaiihctic Races ;
Subdivisions of the Japlietic Races; Chief Hametic
Races; Subdivisions of Ciish ; Suhd i visions of Miz-
raim and Canaan : the Semitic Races ; Subdivis-
ions of the Semitic Races.

No. 26. Tlio Evolutionist at Large. By

Grant Ai.i.kn.

Contents (in part) :— Microscopic Brains ; Slups
and Snails ; Butterfly Psycholof;y • In Summer
Fields; Speckled Trout; Origin of VValnuts ; Do(,'S
and Masters, etc., etc.

No. 27. The History of Landlioldlng
In England. Hy Josici 11 Kisiiku, F.R.H.S.
Contents un part) :— The Aborijiincs ; the Scan-
dinavians ; the Plantagenets ; the Stuarts ; the Ro-
mans ; the Normans ; the Tudors ; the House of
llrunswick ; Land and Labor, etc., etc.

No. 28. Fashion In Deformity, as Illus-
trated in the Customs of Barbarous and Civil-
wed Races. By VVii.i.iam Hknkv Flowkh, F.R.S.
(illustratedV To which is added :— manners
and Fashion. By Hkrukkt Si'en( ek.
Contents (in part) :— Fashions in Coiffure; Tat-
tooing : Deforming the Teetli ; Deforming the
Feet; Eradicating the Eyebrows; Ornaments for
the Nose, Ears, Lips ; Compressing the Skull ;
BAects of Tight Lacing, etc., etc.

No. 80. Paets and FIrttens orxooiogy.

Hy Andkbw \Vii'.nN, PJi.l), (illuhlruleil).

CimfiitH; /o. ; i^ii.d .'I'.lh' ; 'lie .Si a Serpnit»
of Science : Some Animal Architect* ; I'.ii'aHilrit
and Their Uevclopmcnt ; What I iiaw in an Aiu'h
Nest.

No*. 30 and 31. On tl:e Ntudy of
Words. By Ri( iiAni)Ciii.NKw\ Thk.n( n, D.I).
(,'untents : — Introduction : the Poetry in Words;

the Morality in Words; the History in Wnrd^ ;

the Rise of New Words ; the Distinction of Words ;

the Schoolmaster's use of Words.

No. 3*1. Hereditary Traits, and other
Ivssuys. Hy K't iiakd A. Pmn ion, |''.k,A.S.
Contents :- Hereditary Traits; Arlilii iai Som-
nambulism ; Bodily Illness as u Mental Stimulant ;
Dual Consciousness.

No. 33. VlKuettes l>oni Nature. Hy

(iKASI All KN.

Contents (in part) :— Fallow Deer; the Heron's
Haunt; Wild Thynu- ; the Fall of the Leaf; the
Hedgehog's Hole; Seaside Wccils; llic Donkey'i
Ancestors.

Essays. Hy Thomas II, lUx-

nophy ol' Ktyle. Bv

10 winch Is added :- TIlO
.uo. Hy Ai.KXANOKK Uain,

No. 37. Six Lr

TsNiiAi.i., F.R

Contents: — Ir

Theories; Rela

No. 3 1. The

Hhumi'ki Si'im
ITIothor Tot.

l.L.D.

Contents ;~Tlie Principle of Economy applied
to words- Effect of I'iguralivc Language Ivx-
plained; Arrangement of Minor Images in build-
ing up a thought ; The Superiority of Poeiry t<i
Prose explained ; Causes of Force in Language
winch depend upon I-'coiiomy of the Mental Sensi-
bilities ; the Mother Tongue.

No. 3.>. Oriental Uelluions. Edited by
Rev. John Caiuh, D.D., I'resideiit of the Uni-
versity of (jlasgovv.

Contents :— Bralimanism ; Buddhism; Confu-
cianism ; Zoroaster an<l the /end A vesta.

No. 30. Leeturen on Evoliilioii, with a^^

Appendix on the Ntlldy ol' HI«»lo|{y, Hy

TiioMAs H. Ilrxi.i-v, K.K S. (illustrated).

Contents:— The Three Hypotheses respecting
the Ilistorvof Nature; the I'lyiiotliesis of Evolu-
tion—the Neutral and Favorable I'Aidence ; \lie
Demonstrative Evidence of Evolution; the Study
of Biology.

res on Light. By John
stratedt.

ory ; Origin of Physic.il
Theories to Experience ,
Chromatic Phenom,..ui produced by Crystals;
Range of Vision and Range of Radiation ; Sj)cc-
trum Analysis.

Non. 38 and 30. t.eologleal Sketches
at Home an«l AbroatI ; in tuu Parts, each
complete in itself. By Akchiiiai.u Gicikik,
F.R.S.

Contents : Part I ; — My first Geological Excur-
sion ; " The Old Man of Hoy " ; the Baron's Stone
of Killochan ; the Colliers of Carrick ; Among the
Volcanoes of Central France ; the Old Glaciers of
Norway and Scotland ; Rock-Weathering meas-
ured by Decay of Tombstones. Part H; A Frag-
ment of Primeval Europe ; In Wyoming ; The
Geysers of the Yellowstone ; the Lava lields of
Northwestern Europe ; the Scottish School of
Geology ; (jcographical Evolution ; the Geologi-
cal influences which have affected the course of
British History.

No. -10. The Selentlfle EvIdeuee of Or-
ganic Evolution. Hy Gi^okue J. Romanes,
r . R . S .

Contents (in part): — The Argument from Classi-
fication— from Morphology or Structure — from
Geology — from Geographical Distribution— from
Embryology, etc., etc.

No. 41. Current Discussions in Sci-
ence. By W. M. Wii.i.iAMS, F.C.S.
Contents (in part): The Fuel of the Sun; Ori-
gin of Lunar Volcanoes ; Aerial E.xj)loration of
the Arctic Regions ; The Air of Stove-heated
Rooms, etc., etc.

No. 42. History of the Science of Poll-
tics. By FUEDEKICK Pol.l.oCK.

Contents: The Place of Politics In Human
Knowledge ; The Classic Period — Pericles— Soc-
rates—Plato— Aristotle, etc.; the Medieval Period

W,

Co
111.
I'l

F-xcur-

, Siiinc

hllff thl!

tiers ul
ineas-
Frap-

■ ; 'I"'"-"
l-lds of

lool <;(
poio^'i-
Mse of

If Or-

Imanks,

:iassi-
-from
-from

Sci-

; Ori-
lion of
lieatcd

»oll-

Juman
(-Soc-
Veriod

—the pBtmcy %nA the Pmpire ; Rri;lnn!n(f nf the
Moilern IVrioil Maclii.ivilli Moblich ; the Mml
cm I'erioil — I.otWi- Honker Ml » Kit mc — Hume—
McirUfsijiiuu IliirKc ; the I'ri -.cut I ciiiurv lUri-
thaiii Austin Kuiil— S.ivit,'iiy ■ Hirhril S|iiiiirr.

No. I'd. OHru-lii mid lluniliuldt. Ihfir
lilves mid Work*! ( oiuams a srms ut
n lilies (if liarwln, liy lluxloy, Koinuiu's, (•cikio,
Thisflton Dyer ; aU» tlir lalo I'rof. AK.tssix'n
Ontennial Addrrsn on the Lite uiul Work nl
Ale.xamltT von IIuinl)oldt.

Noit. 41 mid 45. The Da«vii oflllMtory i

an iiuinduiiioii to l'rc-lli->t<iru Sliuiy. I'.diuil

tiy ('. 1". Khakv, M.A., of the Hritiiili Mubcuiii.

In (WO I'artH.

Contents of Part I: Karlii'st Traers of Man; tlip
Second Stone A),'e; the (irowth of I.anniianes ;
I'amilies of I.ani'uai'es ; the Nations of the Old
World ; Karly Social l.ile ; the Vill,i;,'c (dmmunity.
Contents of I'arl II: Kelly ion ; Aryan Ueliyion ;
iIk- Other Worlil ; Mythoiciu'ies and Folk 'Pali's;
Picture Writing ; Phonetic Writing ; Comlusion.

No. 40. The DlMrnmoM ol' Ifloiiiory. My

Til. kiHoi, (Traiislaled frmn the French l)y
J. l''rr/.(iKhAi.ii.)

Contents:— Memory as n niolo(,'ical Fact ; Gen-
eral Amnesia; Parti, d Amnesia; Kxaltation of
Memory, or llyperr-nesia ; Conclusion.

No. 47. The < hlldliood of Hollaloiia.

My KowAKi) Ci.uDO, I'.K.A.S.

Contents ^in part): — l.eeends of the Past ahaut
Creation ; C reation as lolil by Science ; Legends
of the Past about Mankind ; Ancient and Modern
Hindu Reli^'ions, etc., etc.

No. 48. Lire III Nature. Pv Jami'.s Himon,
Author of •■ Man itui Ins Dwelliii;^ Place."

C.ntents (IP partK - I'unciion ,■ !.ivin« I'orms ;
Is Life I'niversal ? Nutrition ; Nature and Man ;
the Life of Man, etc., etc,

No. 40. The Sun: -its Constinitlon: Its Phe-
nomena' its ( (indition. Hy N^iiian P. C.mk,
LL.I)., Jud>{e of the Ninth Ju .icial Circuit of
Indiana.

Contents (in part) ;- The Sun's Atmosphere ; the
Chromosphere; the PhotMspherc ; PrmUutlon ol'
the Sun's Spots ; the t>iiestion of tiic iCxtinction of
the Sun, etc., etc.

Num. .'iO and .'•1. HIoiio)' and the ITIeeh*
aiilMin ol* Kxcliaii^^o. Hy Proi. W. Sian-

I.KY JliVO.Ss, F. K.S.

Contents (in parti :— Phe I unctions of Money;
F-arly History of .Monty; the .Metals as .Monev ;
Principles of'Cireulation ; Promissory Notes ; tin
Banking System; ih.: Cleariiit,' House; Ouantily
of .Money needed by a N:ainn, etc., etc.

No. 52. The DimeuMeN of the IVIII. Pv

'Pii. Rnior. (.Pranslatcd Iroin the F'rench by/.
Fitzgerald.)

Contents :— The Question Stated; Impairment
of the Will — L.tck of Imfiiilsion — I'.xcess of Impul-
sion ; Impairment of V<.'luntary attention ; Caprice ;
F-xtinction of the Will ; Coiulusidii.

No. 53. Aiiiinul .liitoiiintiDiii, and Other
Essays. Hy Prof. T. H. Hi xi.kv, F.K.S.

Contents :— .Animal Automatism; Science and
Culture; Elementary Instruction in Physiolojry ;
the Border Territory between Animals and Plants ;
Universities, .Actual and Ideal.

No. 54. The Birth and Growth of

I?Iyth. By F'dwako Ci.oDi), F".R..\.S.

Contents (in part) : — Nature as viewed by Primi-
tive Man ; Sun and Moon in Mytholoy-v ; the Hindu
Sun and Cloud Myth ; Uemonology ; Beast F'ables ;
Totemism, etc., etc.

No. 55. The Selcntlflc BaftlitoriTIoralH,

and Other F;ssays. By William Kini.uo.n
CUFFORD, F.R.S.

Contents-— Scientific Basis of Morals; Right and
Wrong ; the Ethics of Belief ; the Ethics of Re-
MgioD,

No*. CO and 5T. Ilinalonai A P«7*
t-lioluuleul Mtiidy. Ry Iamk-. .>ullv.
('on'cnts: Ptie Sdnly o| Ill'isi .n ; Cl.i'^siliotuin
I'l lllusiuiiH; Illusions of Percept ion | I >rciiiait ,
IlliiMoii. of Intros|u'ttlon ; Other ^.)u.iM-l'resenlt«-
tive Illusions; lllusiiins of Memory; lllusiunn of
Itellel.

NoH, 5K and 50 nwo •Intible niiml)ers, ;<> cento
e.iciii TileOrlulnol'tliieelrM. ByCiiAKLKs

l)\NH IN.

•«• Till* is Unrwin's famous work tom|Jete,
with Index and ^,'lM,^arv.

No. (to. The < hiidhood of the World.

Ily F-iin AKi> t. I Mim, i'.i<..\.«).

Contents iln parli: -Man's I'lrst W.inls, Mann
F'lrst TiM'ls. iMri. I)\Vellin;;s, I'se nf Metals; Lan-
i;iiaj,'i-, WriluiL', ('ciuntiiiL'. Myth', almiil S.un ^.nd
Aloi'ii, Star-.. I'.(lips<s; I(,c,is abniii the Soul, Ik-
llef ill '.Vitihi r.ili, I'eliclilMii, Idolatry, etc., etc.

By Rich-

No. Ul. ITIlNeeiiuiiouiiM I<:m«u)n.

AUIl A. pKiil Kin.

Contents:- Strange Coincidences; Cnlncidence*
and Superstitions; ('■ambllnif Siiperstition«> ■,
l.earnliit; Lan«uai;es; Str.m>;e Sea-('ie,iiuies ; the
< irJKJn of Whales ; Pr;iyer and Wtiitlur.
No. 01 (Iloidil" number, t. cenlsV The He*

lluioiiNurtlie Aiieieiit World.

Ciiiit'iits: Kell;;|i)iis nf the .Am ii iit p"(.,'yptiau>.,
;iiu lent Iranians, .Vssyrl.ms. H.ibylni'.i.ois, aiu lenl
S.iiiskrillc Indi:ins, Phcenu i.iiis. Car'h.ii,'iiiians,
I'',iius.aiis, ancient dreeks iind ;ini lent Unmans.

No. 0:i. ProicreMKlve iTIorallty. Pv

'liMiNM , h'nwi i;i., F'.S..'\., Prc.-.i(kia of Corpus

Cliri.'.ti Collejjc, Oxford.

Conunts:- The Sanctions of Conduct; the
Mnr.d S.ini tinii, or Moral Seiitinuiu ; .Xii.ilysi^
• md I'orin.itinn of the Moral Sentiuviu ; tlir Mnr.d
'Pe^t ; l'x,tm)iles of the practical ai'plicalioiis o(
the Moral 'lest.

No. 04. The Dlntrlbiitlon of Mf'e. fiy

All KKi) Rlsm-.i. Wai lac k and W. P. rni>i-.Lli':N

l>M-.K.

Contents (in parti :-Cieo^'raphical Distribution
of I. and Animals; iJisirjInitlon of Marine .Aid,
mals ; Relations of .Marine with 'Perreslriiil /oolojf-
kal Rc^finiis ; iJistribution of V'eKi't.ilile Lift-,
Nnrtlicrii, Southern. 'I rn|)ical Flora, etc., etc.

No. 05. t'oiidltioiiH «it iTIeiital Dovcl*
opilieilt* and (Jihcr Ls;) ,ys. iiy William
KiNoiio.s CLiiinun, F'.R.S.

Contents :— Conditions of Mental Development;
■Mins and Instruments of Sclciitilii I'liouyht;
.Atoms ; 'Phc l'"lrst :iml the Last Cat,islro|i|ie.
No. 00. Teehiileal ICdiieatioii, , \u\ other

I'.nsays. Hy PiinMAsll IIi.miv. F.k..^.

Contents: — Teclinlc:il I"liic;illon ; The Connec-
tion of the HiolD^ical Sciencss with .Medicine;
Joseph Priestley; On Sensation and the Ciiiiy of
Structure of the Senslferous Or).;;iiis ; fin ''ert.iin
Frrors respecllnt; the Structure of the lleait at-
tributed to .Aristotle.

No. 07. The Ulaek Death ; An ac( rxuit h{

the (jreat Pestlieiice of the nth Century. Hy

J. F. C. HtcKi K. M.I).

Contents :--Gcneral Observations; the Di-iease ;
Causes- Spread, Mortality; Moral IClTccts ; Pliysi-
'ians ; Appendix.

No. 08 (Speci.ll Number, in crntsi. Tlireo
1C!«lia)'A, viz.: Laws, and the Order of tin if
liis.iivervj Origin of Animal Worship; Pnlili-
c;d F'etichism. Hy Hei.iuk r Si'i:nci;k.

No. 09 (Double Number, ;o cents). IfelJell"

ImIII : A Contribution to Anthropolo^'v :Liid tin.-

Hismry of Reliijion. Hv I'"n i ' Scm'I i;i o, Ph I).

Translated from the Germ;in by J. I'"itzL,'< raid,

M.A.

Contents;— The Mind of the Sa^acre ; Rrl.iiion
between the Savage Mind and iis Object ; 1". ti fa-
ism .'US a Religion ; Various Objects c>f I'etlch Wor-
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No. 70. KMMayH, Speculative and Prae*

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Coiui-iUs: Specialized Administration; "The
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No. 71. Aiithrupolu^y. Lly Daniul Wil-
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Contents :— Scope of the Science : Man's I'lacc in
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Sit. 7i. Tlio Dan<-iiii; IVlania of the

iUitiaiu Aa,>'i». Hy J. K. C. Hi-.cKiiK, M.I>.

Contents (in ixirt): -The IJancini; Mania in (Jer-
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Italy; i'lvj l^anciiij^ Mania in Abyssinia.
Nu. T.i, Involution 111 Illtttory^ Lan-
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No. 78. Historical Sketch of the Dis-
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Land Properties ; Saxon Law of Succession to

Land ; Norman Law of Succession ; Inclosure of

Waste Lands, etc.

No. 7». S(-I<>utlflc Aspects ofSonie Fa-
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Contents:— Social Benefits of Paraffin; Forma-
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Ali.assun I'lcni.N.

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Other Kssiiys. liy Rh.haki') A. I'holiok.
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Earlhquiikes ; Our Dual Mrain ; A New "^lar in a

Star Cloud : Monster Sea-Serpents ; Origin of

Comets.

No. 83. Proflt-^hnrin^r Belwccn La-
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CtmtciUs :— Priilit-Shaviiig in the Maison Le-
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liy W. S. Dallas.

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No. 85. The Essential Nature of Re-

ll{{lUII. liy J. Al.LA.N.so.N I'lClO.N.

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No. 8«. The IJiiMecn Vnlversc. Also
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liy VVm. Ki.NoDcj.N L.L11- 101:11, F.R.S.

Contents:— The Unseen L'niverse; Philosophy of
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No. 87. The Morphine Habit (^Tlor-
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Contents :— General Description of Morphino-
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No. 88. Science anci Crime, and other

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No. 89. The Genesis of Science. Bjr

HeRUKKT SrENLEK.

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