3 Ib. 323-
AUGUSTS DE LA RIVE. 14!
to meet. His doctor, and those who nursed him in his
last illness tell us that no suffering could alter or em-
bitter the sweetness of his character 1 .
J.-B. Dumas in one of his brilliant discourses before
the Academy adds to the names we have mentioned
still another. "Ampere, Faraday, Auguste De la
Rive", he says, "made electricity the study of their
lives, and enriched the science with great discoveries;
they were all three deeply religious." 2
The authority of a man like Dumas is not to be
ignored, and his praise of De la Rive is in no way
exaggerated. Both as a discoverer and as a student of
contemporary science, the latter was a man of the highest
distinction. In questions of religion he was of one mind
with his friend Faraday, as is shown by the correspon-
dence which passed between them.
"He believed", said Dumas, "that human personality has
its seat elsewhere than in the dust of which our bodies are
composed. Is it to be supposed that matter, which obeys, is
imperishable, while spirit, which commands, is perishable?
'I prefer to believe', said De la Rive, that the reasoning
soul is immortal and that unreasoning matter is doomed to
destruction.' He regarded the universe as having come into
existence through an act of creation. For he was able to
demonstrate, as a truth of the purely scientific order and
by arguments which were more fully developed by Clausius,
that the world did not always exist and that it cannot for
ever continue in existence." 3
"A devoted adherent of the Protestant Church of Geneva
he none the less profoundly venerated the Catholic Church,
in which he had many friends and relatives, and to which
belonged the majority of the population of Presinge, his
place of residence. Universally respected by his Catholic
1 Ib. 412. 2 Discours I 277.
3 Dumas, Discours I 277.
142 IV. PHYSICS. I. THEORY OF ELECTRICITY.
neighbours he sympathised with all their undertakings, moral
and religious, and even contributed on occasion to the
repair of their Church. The spirit of religious tolerance
was so native to the mind of our colleague that he made
it a law to himself to avoid everything that could give the
slightest offence to the convictions of others. But there
are times when to be silent is to be false to one's faith,
and De la Rive was unwilling that it should be supposed
that those who preached materialism in the name of science
enjoyed the sanction and support of all men of science.
'That is not true', he said, 'and it is our duty to proclaim
its untruth.'" *
If De la Rive was inclined to believe in the final com-
plete destruction of unreasoning matter, the theologian will
observe that the teaching of Christianity does not include
any such destruction. The 'destruction' foretold in the
Apocalypse is limited to a breaking-up of the present form
of the universe ; it does not go so far as complete an-
nihilation. St. Thomas Aquinas expressly proposes it as a
question whether any created thing will be annihilated and
replies in the negative 2 . His reasons for ascribing even to
the material world, or at all events to its fundamental
constituents, eternal duration are derived from a consideration
of the nature of God and of the matter which He has
created. The whole form and fashion, in which the latter
exists, implies a destiny other than that of annihilation. We
thus find "mediaeval" theology more modern in this point
than the modern savant De la Rive 3 .
1 "Cela n'est pas, disait-il avec fermete, et notre devoir est de le
proclamer" (ib. 299).
2 Unde dicendum est , quod nihil omnino in nihilum redigetur
(S. Thorn. I, q. 104, a. 4).
3 From the theological point of view, explanations and qualifications
like those which we have appended to De la Rive's words, might be
added to many of the passages quoted from the scientists. However
when the passages cited were on the whole correct, we have refrained
from remarks, which might perhaps earn for us the reputation of fault
finding. Meanwhile we must defend ourselves from the supposition
SIEMENS AND WEBER. 143
We have dealt with those pioneers of electrical science
who have given their names to the standard electrical
units ; we may add two others : Von Siemens and
The resistance of substances is at present calculated
in ohms. Before the adoption of this unit, that as-
sociated with the name of Von Siemens was widely em-
ployed; but Wilhelm Weber's services in the measure-
ment of electricity gave him at least an equal claim to
be so honoured. To these two scientists we shall de-
vote just a few words.
Werner Von Siemens (f 1892) was scientific ad-
viser to the famous firm of Siemens and Halske, and
in his day stood at the head of electro-technicians. This
position he owed to the fact that he possessed not
merely a technical but also a profound scientific know-
ledge of his subject: and when the perfecting of elec-
trical apparatus necessitated the solution of problems
hitherto unfaced, he was equal to the task. Siemens
in 1867 formulated the principle of the dynamo, made
valuable contributions to the theory of the submarine
cable, and, especially after 1874 (when he became a
member of the Berlin Academy of Science) published
a long series of works on theoretical physics J .
that we are in entire agreement with every word and thought which
we shall quote.
1 Hovestadt in Natur und Offenbarung XXXIX, Minister 1893,
167 171. A brother of Werner v. Siemens, William Siemens
(f 1883), settled down in England and distinguished himself by his
achievements in science as well as in technology (W. Pole and
E. F. B a m b e r , Life and scientific works of the late Sir W. Siemens.
London 1891, 4 vols). He concluded his opening address to the
British Association 1882 as follows: "We shall thus find that in
144 IV. PHYSICS. I. THEORY OF ELECTRICITY.
The "Naturanschauung ' to which he was led by deep
and laborious study finds expression in his Address to the
Association of Physicists in 1886: "The deeper we pene-
trate into the harmonious and immutable order of nature,
and unveil her hidden forces, the more modestly do we
come to think of the little compass of our knowledge, and
the more intense is our admiration of the supreme ordering
Wisdom which pervades the whole created world." l
Wilhelm Weber (f 1891), one of the celebrated
Seven of Gottingen, who in 1837 surrendered their posts
rather than swear allegiance to the new government,
stands in the first rank of German physicists. He worked
at the theory of wave-motion, and acoustics, but above
all at electricity. His celebrated electro-dynamic law
is indeed no longer accepted, but even his critics admit
that Weber's conception bears the stamp of genius, and
it held the allegiance of scientists for a long time 2 .
Weber is also remembered for his contributions to the
measurement of electricity, and he was, with Gauss, the
first to apply (in 1833) the galvanic current to telegraphy.
Reinke includes Weber in his list of great scientists
who were also believers 3 . A somewhat longer biography 4
which we have seen, although entering as little as possible
the great workshop of Nature, there are no lines of demarcation
to be drawn between the most exalted speculation and commonplace
practice , and that all knowledge must lead up to one great result,
that of an intelligent recognition of the Creator through his works"
(Report of the 52 nd meeting of the British Association for the Ad-
vancement of Science, held at Southampton in August 1882 [London
1883]. President's Address p. 33)
1 Ib. 170.
9 H. Hertz, Uber die Beziehungen zwischen Licht und Elek-
trizitat, Bonn 1889, 7.
3 J. Reinke, Die Welt als Tat, Berlin 1903, 468.
4 Leopoldina XXVIII, Halle 1892, 147 169 178 185 201.
W1LHELM WEBER. WILLIAM ROBERT GROVE. 145
into religious questions testifies that he "preserved all his
life the heart and faith of a child" l . We find in it the
following account of his death : "At midday he fell asleep,
seated in an arm-chair. As the sun was sinking in the
West he awoke again, and his eyes, bright and eager,
strained out into the distance ; their gaze was no longer
fixed on the things of earth but uplifted to that sublimer
reality for which his heart had so long hungered." 2 We
have in this passage, despite the somewhat rhetorical style,
clear evidence of Weber's belief in the immortality of
William Robert Grove (f 1896), who also took
electricity for his province, says at the close of his
celebrated book "On the Correlation of Physical
"It is a great assistance in such investigations to be
intimately convinced that no physical phenomenon can
stand alone: each is inevitably connected with anterior
changes, and is inevitably productive of consequential
changes, each with the other, and all with time and space ;
and, either in tracing back these antecedents, or following
up their consequents, many new phenomena hitherto be-
lieved distinct will be connected and explained: explana-
tion is, indeed, only relative to something more familiar,
not more known, i. e. known as to causative or creative
In all phenomena the more closely they are investigated,
the more are we convinced that, humanly speaking neither
matter nor force can be created, and that an essential cause
is unattainable. - - Causation is the will, Creation, the act,
of God." 3
1 Ib. 201.
2 Ib. 204.
3 W. R. Grove, On the Correlation of Physical Forces : being
the substance of a course of lectures delivered in the London Insti-
tution in the year 1843, London 1846, 48 50.
Kneller, Christianity. 1O
146 IV. PHYSICS. 2. THE THEORY OF LIGHT.
2. THE THEORY OF LIGHT.
To the second half of the ig ih century belong the
development of the theory of electricity, and the esta-
blishment of the mechanical theory of heat. The first
half saw, indeed, the discovery of many fundamental laws
of electricity, but it is significant in the history of science
mainly for the formulation of the modern theory of light.
Fresnel, Fraunhofer, Fizeau, Foucault are the names that
come to everyone's lips in this connection; it is to
their labours that we owe the current conception which
regards light, not as a substance, but as a wave-motion
in the ether.
The external life of the great Augustin Fresnel 1
is soon told. Born on May io th 1788 at Broglie in the
Department of Eure, he received his early education
at home, and subsequently went to the Central School in
Caen, to the Polytechnic, and to the School of Engineer-
ing in Paris. He then obtained a post as engineer in
the North of France. When Napoleon returned from
Elba, Fresnel considered himself bound as a good Royal-
ist to take service in the army of the South. The out-
come was that he secured leisure for scientific studies;
for after the triumph of Napoleon he was deprived of
his position as engineer and placed under police super-
vision. Fresnel now began his investigations into the
nature of light; and, thanks to the kindness of his
superiors, he was able to continue them after his resto-
1 CEuvres Completes d' Augustin Fresnel, publiees par MM. Henri
de Senarmont, Emile Verdet et Leonor Fresnel, 3 vols,
Paris i866f. Duleau, Notice sur A. Fresnel, printed in the Rev.
Encyclopedique XXXIX, livr. 117, Paris, Septembre 1828, 558 567.
AUGUSTIN FRESNEL. 147
ration to office. The essays published by him during
1819 1827 on refraction, interference, and related sub-
jects are few in number, but every one of them is a
masterpiece. He also made many improvements in the
apparatus used in lighthouses. He died young, not yet
forty, on July 14 th 1827, at Ville d'Avray near Paris.
The famous physicist came of a deeply religious
family. Thus his mother writes in 1802 in reply to a
letter from his elder brother asking news of Augustin,
then at college: "I pray God to give my son the grace
to employ the great talents, which he has received,
for his own benefit, and for the God of all. Much will
be asked from him to whom much has been given, and
most will be required of him who has received most." 1
Augustin inherited this religious habit of mind. During
the early years of his life as an engineer he was almost
friendless, and was cast wholly on his own resources.
He sought distraction in study, and with all the greater
ardour inasmuch as he had never any taste for the
practical life. "But the first inclination of his life was
by no means to optics. Under the influence of a home
education in which religion had held the first place he
began to reflect on philosophical problems, and en-
deavoured to reach a rigorously scientific proof of certain
of those doctrines to which he adhered with an ardent
belief. But he never opened his mind on these questions
save to members of his family or to his most intimate
1 CEuvres Completes I, Paris 1866, xcvm.
2 Sous 1'influence des souvenirs d'une education de famille ou la
religion avait tenu la premiere place, il commenga a mediter sur les
questions philosophiques et s'efforga de trouver une demonstration
148 IV. PHYSICS. 2. THE THEORY OF LIGHT.
The editor of Fresnel's scientific works shows little
inclination to dwell on the religious side of his character,
but in spite of this we find many proofs that the great
scientist remained all his life an adherent of the "Spiritual
School" 1 . We find notes for instance of an essay in
defence of the doctrine of immortality forwarded by
Fresnel to a sceptical uncle of his.
Fresnel's piety of disposition remained unaltered
down to the last moment of his life. His friend, the
engineer Duleau, who nursed him in his last illness, tells
us that the constant theme of his conversation was the
greatness of God, Whose power and wisdom he saw
manifested in every part of nature. He always regarded
his own intellectual endowments as a gift from God,
and held it a duty to employ them for the advance of
knowledge and the benefit of his fellow men. The thought
of his untimely death and of the works he was com-
pelled to leave unfinished, in no way troubled his de-
votion ; there was something higher, he said, for mankind
than science and genius 2 .
scientifique et rigoureuse de la verite de quelques-unes des croyances
qui avaient ete jadis pour lui 1'objet de la foi la plus ardente ; mais
il ne communiqua jamais ses pensees qu'aux membres de sa famille
et a ses plus intimes amis (CEuvres Completes I xxvm).
1 On August 5 th 1811, Leonor Merimee writes to his nephew
Aug. Fresnel : "J'ai serre" dans mon tiroir ta lettre philosophique, pour
la reprendre quand j'aurai le loisir de debrouiller ma case de meta-
physique." Here Leonor Fresnel makes the marginal note : "II s'agit
sans doute d'un essai psychologique , ou A. Fresnel developpe les
principaux arguments sur lesquels se fonde la doctrine spiritualiste,
dont il fut toujours defenseur" (Ib. II  811).
2 "II a vu approcher sa fin avec les sentiments religieux d'un homme
qui, ayant ete initie plus avant que ses semblables dans le secret des
merveilles de la nature , etait profondement penetre de la puissance
JOSEPH FRAUNHOFER. 149
Such is the testimony of Duleau, and if his words
are in certain respects a little vague, they are, as regards
the aim of this book, clear and unmistakable. Unbelief
can make no appeal to the authority of Augustin Fresnel.
The same can be said of our great countryman Joseph
Fraunhofer (born about a year earlier than Fresnel,
March 6 th 1787, died a little less than a year before
him, June 7 th I826) 1 . The story of his life and labours
et de la bonte infinies de leur auteur. Les services qu'il rendait aux
sciences par ses meditations, les applications utiles qu'il en a faites,
n'etaient a ses yeux que 1'accomplissement d'une mission pour lui
obligatoire. C'etait surtout par la pratique des vertus les plus touchantes
qu'il croyait pouvoir s'acquitter envers 1'humanite et qu'il satisfaisait
sa conscience. C'est a moi . . . qui ai assiste a ses derniers moments,
qui ai recueilli ses dernieres paroles, de dire quels etaient ses prin-
cipes severes et invariables ; son adoration pour la vertu, qu'il plagait
bien au-dessus de la science et du ge"nie ; sa force d'ame, je ne dirai
pas centre la mort seulement , mais contre 1'interruption des decou-
vertes , qu'il avait preparees et ebauchees , et dont il esperait tirer
des applications utiles ..." (Duleau, Notice, in Revue encycl. XXXIX
566 567). Arago says in his Eloge on Fresnel, referring to his
frame of mind during the last days of his life : "Toutes ses pensees
s'etaient tournees vers sa fin prochaine, tout 1'y ramenait." Not even
the presentation of the Rumford medal, one of the highest honours
which England has to give , made any impression on him (CEuvres
completes III 525 526).
1 F. Thiersch in Bulletin der konigl. Akademie der Wissen-
schaften, Munchen 1852, 126 143. Ph. Jolly in Allg. deutsche
Biographie VII 323 325. Cf. (U tzsch n ei d er) Kurzer Abrifi der
Lebensgeschichte des Herrrn Dr Joseph v. Fraunhofer, in Kunst- und
Gewerbeblatt fur Bayern vom Jahre 1826. Ph. Jolly, Das Leben
Fraunhofers. Rede an die Studierenden der k. Ludwig-Maximilians-
Universitat zu Miinchen, gehalten am 2. Dezember 1865, Munchen
1866. C. M. v. Ba u e r n f e in d , Gedachtnisrede auf Joseph v. Fraun-
hofer zur Feier seines 100. Geburtstages. Munchen 1887. J os - von
Fraunhofers Gesammelte Schriften , herausgeg. von E. Lorn m el,
I5O IV. PHYSICS. 2. THE THEORY OF LIGHT.
is well known; it exhibits the spectacle of a man of
supreme intellect and iron industry, stubbornly battling
with obstacles that all but succeeded in overwhelming
him. As an orphan of eleven, he came from his native
Straubing to Munich, and was there apprenticed to a
maker of mirrors, who undertook to teach the delicate
lad on condition that he worked for six years without
pay. Some diagrams that he saw on the walls of the
Sunday School made him aware of the existence of a
science of Geometry. He bought a text-book for a
couple of kreutzers, and set to work to master its
contents. But everything was against him. His com-
panions ridiculed him; his master did everything he
could to stifle this itch for useless learning; others,
whose advice he sought, told him that his project
was hopeless. An accident helped him on. His master's
house toppled down , imprisoning him in the ruins ;
and his rescue after four hours' excavation made him
an object of public notice. The Elector, Max Joseph,
and Utzschneider interested themselves in him and help-
ed him in his studies with money and advice. After
six years' hard work he was so far advanced that
he obtained an appointment as optician in the Insti-
tute of Reichenbach and Utzschneider, and was set
to work at the erection of geodetic and astronomical
1 The Institute was situated within the walls of a former Bene-
dictine Monastery. The Benedictines, Ulrich Schiegg and Niggl,
deserved well of it, aiding it with scientific advice. For the astro-
nomer Schiegg (1752 1810) cf. A. Lindner, Die Schriftsteller
und die um Wissenschaft und Kunst verdienten Mitglieder des Bene-
diktinerordens im heutigen Konigreich Bayern II, Regensburg 1880,
98 101. Bauernfeind in Allg. deutsche Biogr. XXXI 180.
JOSEPH FRAUNHOFER. 151
This marked the beginning of a new life for Fraun-
hofer. The telescopes made by him, were perfect in
every respect, as well in their measuring apparatus as
in their lenses, and inaugurated a new epoch in obser-
vational astronomy. "A striking proof of their excellence,
almost to our day, is afforded by the fact that members
of the Astronomical Commission, appointed by the German
authorities to observe the transits of Venus in 1874 and
1882, employed instruments which had been made in
Fraunhofer's workshops and under his personal direction.
With the single exception of apparatus for photographing
the transit - - a process undiscovered in Fraunhofer's
time there was nothing that had not proceeded from
the hands of the great scientist." * His brilliant achieve-
ments are to be ascribed, however, not so much to
mere manual skill, as to his firm grasp and vast know-
ledge of the scientific side of his subject. To grapple
with the practical problems, encountered in the con-
struction of achromatic lenses, a perfect mastery of
methods hitherto in use was not enough; there was
needed also a genius for independent research in theo-
retical optics. Fraunhofer possessed such genius, and
he "enriched the physics of Light with epoch-making
discoveries". The so-called Fraunhofer lines of the
sun's sceptrum bear witness to one sphere of his activi-
ty ; his works on the diffraction and refraction of light
are held in high estimation; and his determination of
the wave-lengths of light of various colours is remark-
able not only for its wonderful accuracy, but for the
part it played in establishing the undulatory theory
1 Bauernfeind, Gedachtnisrede 15.
152 IV. PHYSICS. 2. THE THEORY OF LIGHT.
Unfortunately, at the early age of forty, Fraunhofer
was snatched away by a painful and incurable disease.
"His demeanour under acute suffering was that of a
sterling Christian. He showed no impatience and uttered
no complaint, but resigned all hope of recovery to the
Divine Will which had brought him forth into life from
the night of nothingness."
"Fraunhofer was a man of disciplined and benevolent
temper, occasionally clouded, it is true, by outbursts
of his natural irritability. He was a loyal adherent of
his religion, so thorough in his obedience that even
those invited to his house were obliged to observe the
prescribed fasts and abstinences, a remarkable contrast,
surely, to the licence of his day." 1
On many essential points of the Theory of Light
Fresnel had been able to advance only conjectures, and
on many others he accepted, as proved, certain laws
which demanded further investigation. Much remain-
ed for his successors in the development of the new
theory, and men of genius were found for the task.
"No physicist of our time", says Cornu 2 , "has con-
tributed more to the final formulation of the wonderful
wave-theory than Fizeau." This was an invaluable service
to science, and it bore fruit in other departments than
that to which it was first applied.
1 Historisch-politische Blatter XI, Miinchen 1843, 4^5- That
Fraunhofer was a sincere Catholic is also testified by J. N. von Ringseis
in his speech as rector, II th December 1855; v. E. v. Ringseis,
Erinnerungen an J. N. v. Ringseis IV 322 331.
2 Cornu, L'ceuvre scientifique de M. Fizeau, in the Annuaire pour
1'an 1898, public par le Bureau des longitudes, Notice C, reprinted
in Cosmos, 17 et 26 sept. 1898, 374 379 400 405.
AUMAND HIPPOLYTE LOUIS FIZEAU. 153
Armand Hippolyte Louis Fizeau, born 1819,
was the son of a Professor of Medicine at Paris, and
was originally intended to follow in the footsteps of
his father. His medical studies were however inter-
rupted by illness, and this gave him an opportunity of
cultivating his taste for physics. Before long he en-
gaged in independent experiment and research. He first
turned his attention to the recently invented Art of
Photography, and in the year 1841 he introduced many
improvements. The daguerrotypes of the time were
faint, impermanent, and very slow in developing. Fizeau
expedited the process of development a hundredfold
by the use of bromides, and by the application of cer-
tain salts of gold produced pictures at once vivid and
lasting. The first discovery was made in conjunction
with another scientist who was to be one day famous,
Leon Foucault. They also investigated the photo-
graphic activity of various sources of light, and pro-
duced successful photographs of the sun and its spots.
The conclusion of their paper on these latter, laid be-
fore the Academy in 1845, marks "a new epoch in the
history of optics". Sound-waves grow weaker as they
diffuse themselves over a wider area, but in all other
respects remain unaltered. Does the same hold good
of light- waves? There were reasons to doubt it, and
the lack of certainty on the point involved the theory
of light in some obscurity. Fizeau and Foucault now
showed that even after thousands of vibrations there
is no change either in the shape or form of indi-
vidual waves , or in their relation one to another.
Fresnel had assumed that this was the case, but his
assumption had not been raised to the plane of an
154 IV. PHYSICS. 2. THE THEORY OF LIGHT.