18.05.2020 Investigating Victor Regnault’s Principle: The Result of any Experiment must be Straightforward and Clear.

This article is published in the occasion of the discovery of a daguerreian self-portrait by Victor Regnault

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Henri Victor Regnault (1810-1878) was not only a remarkable professor and experimenter in chemistry and physics but also a central figure during the earliest years of photography in Europe: Arago called on him for experiments as early as January-March 1839. Regnault experimented on the daguerreotype along with Humbold, Becquerel and Moser, also experimented the Talbot process in Paris, supported Blancquart-Evrard, encouraged Le Gray to develop various negative processes. He founded the Society Héliographique, was the first president of the Société Française de Photographie (SFP) and practiced photography until a tragic laboratory accident in 1856.

Early daguerreian portrait to be identified, circa 1841-1844

This article will present some biographical aspects of Victor Regnault, then a few elements about his activities in relation to photography and then will consider identification of this portrait.

Victor Regnault was born in Aix-la-Chapelle (then part of the French Empire) the 21st of July 1810. His father André Regnault, captain in the corps of civil engineers, died in 1812 on the road to Wilna during the Russian campaign. Six years later, at the age of eight, Victor and his younger sister moved to Paris after the death of their Italian mother, Marie-Thérèse Massardo. They were taken in by a comrade-in-arms of their father, Jean-Baptiste Clément, whose wife was the daughter of Alexandre Duval, member of the French Academy. Teenage Victor worked as a clerk for a drapery firm, spending all of his spare time at the National Library and early on showed aptitude for mathematics.

Gustave Le Gray,
For identification purpose, the portrait, a mirror image, is reversed and enlarged (now designated as “DAG”)

Victor entered a preparatory institution for the École Polytechnique. He passed the admission exam in 1830 and we have many details from VR biographer, (J-B Dumas) : “Victor se présenta avec sa figure pâle, son menton imberbe, sa longue chevelure blonde, ses traits amaigris par la maladie, altérés encore par la fatigue d’une longue route en diligence …” (Victor presented himself with his pale face, his beardless chin, his long blond hair, his features thinned by illness, altered again by the fatigue of a long distance journey…).

Important for our identification : Victor Regnault has been described in the Polytechnique’s register: “Cheveux blonds – Front découvert – Nez moyen – Yeux bleus – Bouche moyenne – Menton pointu – Visage ovale – Taille 168 cm” Blond hair – Open forehead – Medium nose – Blue eyes – Medium mouth – Sharp chin – Oval face – Height 168 cm.

  • Long blond hair
  • Beardless sharp chin
  • Blue eyes
  • Height 168 cm (when the average French male height was less than 162 cm)

Henri Victor Regnault by his cousin, Eugène Amaury-Duval, c. 1838 (we call it “EAD”)

Regnault entered the École des Mines on September 1832.

At the age of 26, he was holding two positions, one at the Ecole des Mines and one at the Ecole Polytechnique, as répétiteur for Gay-Lussac. When Gay-Lussac retired in November 1840, Regnault was named to the coveted chair of chemistry at the École Polytechnique. Afterwards, he became Professor of physics at the Collège de France (1841), as the Chair of general and experimental physics. There, he began his life’s work in physics by studying the specific heat of elements and compounds.

In April 1852, Regnault was appointed Director of the Manufacture Impériale de porcelaine de Sèvres. There, he combined his administrative duties at the Manufacture with his teaching and research at the Collège de France. Regnault also took part in the creation of the Parisian Gas Company, and an experimental Gaz factory was built in Saint-Cloud, near the Manufacture. The Emperor, wishing to keep his promise to deliver affordable gas to Parisians — he had been elected with the program for Paris: “Eau et Gaz à tous les étages”— charged Regnault with conducting experiments to determine the real cost price of gas.

In August 1856, Regnault suffered a severe fall in his laboratory, fell into a coma for twelve-days, and never made a full recovery.

Bertall .Victor Regnault after his accident, c. 1867 (VR5)

Regnault had been elected to numerous scientific societies, including the French Society of Physics in 1838, the French Academy of Sciences in 1840 — at the impossibly young age of 29, the Royal Swedish Academy of Sciences in 1851, the Royal Society of London in 1852, the American Academy of Arts and Sciences in 1855… He became President of the French Academy of Sciences in 1855.

“A singular work power, an unalterable clarity of mind, a natural aptitude for the mathematical part of the studies, a hand of the rarest skill for graphic work, nothing was missing… “

Regnault’s principle is that the result of any experiment must be straightforward and clear.

“He uses complicated mechanisms, it is true; but if the apparatus is complex, the phenomenon to be observed is simple … the doctrine that has constantly directed Regnault is there in its entirety, and, in bringing it to light, he has rendered the sciences a service that will not be forgotten, for it extends to the art of questioning nature in all directions, and it constitutes the first and most important precept of the experimental method…

His teachings at the College de France, in the Chair by the rigorous discussion of principles, in the laboratory by the skillful execution of experiments, and in conversation by the lively improvisations of an unprejudiced, open and free mind, had transformed his amphitheater into a veritable academy where the statue of Truth hung, and his lessons, from which all devotion to the imagination was banished, into a course of higher physics, without precedent in France.” (J.-B. Dumas, Éloge)

Dated self-portrait of VR at the College de France, March 1846 (VR1)

However, destiny still had a sad surprise in store for him. 1830 was a troubled time; the École polytechnique was the focus of riots, the students armed with guns. By suddenly raising his weapon, Regnault broke a lamp whose glass, shattered by the shock, fell and penetrated his left eye, making him fear the loss of the organ and making, in any case, long rest necessary…

The life of a scientist in search of natural truths is similar to that of a soldier; it has the same perils; it requires the same composure… Regnault possessed to the highest degree the moral courage that is surprised by nothing.

The dangers he had run, the day when boiling sulphur vapor set fire to his workshop, or when the explosion of a matras full of boiling mercury had ploughed and scarred his face, or when an iron container full of liquid carbonic acid burst like a shell in his hands, he never spoke of them. He seemed to consider himself invulnerable.” (J.-B. Dumas, Éloge)

  • Left eye: we hardly see any scar on the different portraits
  • Boiling mercury, we notice possible scars on 1846 self-portrait (VR1)

Variant self-portrait of VR at the College de France, same day, March 1846 (VR1b)

Victor Regnault became involved with photography as early as March 1839.

We can deduce that early date since his article about photogenic properties of the secret components of daguerreotype was published by Arago in his Annales de Chimie et de Physique in March 1839. You can access the text as a pdf on Gallica by clicking here or on the following image. One person got very excited when reading and understanding it.

Sir Herschel wrote the next day to WHF Talbot:

18 March 1839. “Dear Sir, Many thanks for the specimens of your sensitive paper – It really deserves the name, and in fact so far surpasses my expectation from any trials I had made that I cannot help congratulating you on your hitting on so very valuable and curious a discovery.

I handed over all my best specimens of copies of engravings to the Royal Society and owing to want of Sun yesterday or today I have none worthy of sending to Baron Humboldt. but I thank you much for your offer…”

Victor Regnault article, March 1843. It may be of interest to the reader to notice that Bibliotheque nationale’s copy is Victor Regnault personal copy, bearing his signature on the end-papers.

“… in the last Number of the Annales de Chimie there is a Chemical paper which contains a hint which I think may turn out to be the key to Daguerre’s process. The curious habitudes of Chlorine in relation to Carbon & hydrogen under the influence of Light have long been known – and in a note to the “Notice” I handed into the RS on Thursday, allusion is made to these reactions as a possible mode of “photogeny”– Well. Monsieur Regnault’s paper above alluded to mentions one reaction so marked & vivid not only under sunshine but in daylight that it seems hardly possible it should not become available some-how or other.

The Experiment is this: Take of the oily liquid produced by action of Chlorine on Olefiant gas – quantum sufficiis put it in a shallow dish & pour over it a stratum of water – Then place it in an atmosphere of Chlorine. This will be copiously absorbed and a liquid is produced which is permanent in the dark but decomposes as above described in the light. –
Now. NB. The “oily liquid” has also been called chloric ether and as you mentioned “muriatic ether” in a late letter as one of Daguerre’s re-agents this seems to strengthen the suspicion that we are to look in this direction for his proces
s. — Yours very truly, JFW Herschel

Regnault’s involvement in the history of photography is an interesting subject, still to be investigated. In Talbot’s correspondance we find another decisive letter sent by Biot to Talbot after receiving photogenic drawings at the Academie des Sciences :

“Paris. 14 June 1841 … Since I feared that I was not myself sufficiently practiced in the production of photogenic pictures to make good use of the samples of your paper which you had sent me, I handed them over to one of my younger colleagues, Mr Regnault, as skilled a Physicist as he is a learned chemist. He had already made some daguerrian proofs for his own enjoyment, which were very successful. Consequently, you can rest assured that these samples will be used with the greatest care, skill and interest…” (J.-B. Biot to H. Fox Talbot, Lacock Abbey).

So Regnault was in charge and his interest in daguerreotype is confirmed in June 1841. Next piece of evidence arrives from Germany, from his native town, Aix-la-Chapelle or Aachen as German call the town.

Höchst interessante Versuche über Daguerreotyp-Bilder von Herrn Moser in Königsberg. Aus dem Französischen des Herrn Regnault, Aachen, Verlag der Roschütz’schen Buchhandlung (P. Fagot), 1842, in-8, 16 pages

This early daguerreotype handbook was offered for the price of 18 kr. but did not sell well. We could trace one copy in the Library of the Austrian Photography proto-historian José-Maria Eder, now secured at the Albertina.

Ludwig Moser (1805-1880) was a German physicist and university lecturer, associate professor of the Faculty of Philosophy at Albertus University in Königsberg. In 1839 he was appointed to the chair of physics. Moser was concerned with the earth’s magnetic field and light. In 1841 he was the first to use the daguerreotype for stereoscopy. He critically examined Goethe’s theory of colours (Goethe), of which he was particularly proud. Sir Hershell discussed the Moser-images described in this booklet.

How long did the interest for metallic plates last ?

We have no idea, since until now no daguerreotype has never been found. One portrait of a man is listed by Photo-Arago with a question mark. The sitter has whiskers, when Regnault seems beardless since his birth. If a daguerreotype should be attributed to Regnault, the period of time for its creation would be limited, as all the pieces of evidence of Regnault’s involvement after 1843 point to paper photography :

Heathfield. “2 March 1843. My dear Sir, I am afraid that you imagine I either underrate or have not fairly tried your beautiful discovery; neither of which I assure you is the case; I admire it beyond measure, and tried it at Paris with M. Regnault and M. Bayard <2> (the latter succeeded in making an excellent portrait of myself) the only thing which deterred me from doing much more was the apparent want of a more perfect and sure medium of transmission in the way of paper As we found it continually playing tricks in the form of blotches and spots. if you could refer me to any means of avoiding these, I shd be very much obliged. M. Bayard’s process is quite different from yours…” (Reverend Richard Calvert Jones to H. Fox Talbot, Lacock Abbey).

On 29 May 1843, Talbot dined with Bayard and Regnault, among other French pioneers of paper photography: Jean-Baptiste Biot (1774-1862), Talbot’s main supporter in the French scientific community, the physicist Hippolyte Fizeau (1819-1896), and the chemist Jean Louis Lassaigne (1800-1859). Talbot was dreaming to create in Paris an “Ecole Normale de Photographie”, with the financial support of Count Bassano.

The C.R.A.S. or Comptes rendus of the Académie des Sciences record the “frequency with which Regnault was asked to test the many photographic improvements brought before the Academy in the 1840s. One of the most significant of these was presented by Louis-Désiré Blanquart-Evrard, an inventor from Lille who brought forward an improved paper photography process that ultimately succeeded in outflanking the stifling patents Talbot had placed on paper negative photography. In 1847, Regnault chaired the academic committee that examined Blanquart-Evrard’s process, and it is [no doubt] possible that this experience inspired his subsequent surge of photographic activity.” (Poncet, & Dahlberg. The legacy of Henri Victor Regnault)

D. Blanquart-Evrard. Photographic demonstration at the College de France, probably 1847

This unique print, located in the Regnault album, entered the collections of the Société française de photographie in 1923 through a donation by Jean Mascart. Since that time, this album remains the cornerstone of the history of French photography. Among the authors of the paper photographs composing the album, we can list:

  • William Henry Fox Talbot
  • Amélie Guillot-Saguez
  • Gustave Le Gray
  • Victor Regnault
  • Désiré Blanquart-Evrard

The legends under the various salt paper prints attest unambiguously to the experimental and scientific dimension of the album, a unique source documenting the processes with negatives on glass and paper in the 1840s. Roger Fenton came to Paris to work with Gustave Le Gray and reported his interest for this album in , “Photography in France”, The Chemist. A Monthly Journal of Chemical Philosophy, vol. III, n° 29, February 1852, p. 221.

Blanquart-Evrard. VR during another photographic demonstration at the College de France, April 1847

Elected by acclamation in 1855 as first President of the newly constituted French Society of Photography, Regnault set about creating a Museum of Photography, a library, and an experimental laboratory and contributed significantly to the numerous and important innovations that this artistic and scientific association brought to the various branches of Photography.

The following year, in 1856, a severe brain accident slowed down all of Regnault’s activities.

VR, Outdoor self-portrait at the College de France, circa 1847 (VR2)

Victor Regnault created at least six self-portraits, or made them with the assistance of colleagues as Désiré Blanquart-Evrard. His French biographer insists on several occasion on his personal reluctance to get credit for every action. He shared this old-fashion scientific modesty with Hippolyte Bayard.

Regnault’s delicate Seine scenes and landscapes were rediscovered with Marie-Therese & Andre Jammes’ collection auctions held at Sotheby’s, London and Paris. Some of his original paper negatives have also surfaced.

Victor Regnault, self-portrait with cigare, probably at Sèvres, after 1852 (VR3)

There is no trace of any Regnault’s photographic activity after the accident. Incidentally a late carte-de-visite portrait surfaced on the internet:

When we first use a face-recognition software, the AI found on internet a little known portrait of Regnault after his accident, a cdv with the address of Léon Crémière, 28 rue Laval. The Archives Nationale Durand Dictionary states that Cremiere lived and worked at this address from 1860-1869.

Léon Crémière, Victor Regnault after a stroke, Paris, after 1860 (historyofphotographyarchive.com, VR4)

For the identification of the daguerrian portrait, “DAG”, we will compare with the painting “EAD”, the three self-portraits with the best definition “VR1”, “VR2”, “VR3”, and finally the late carte-de-visite, “VR4”.

Before anything, we will submit them to the online software, betaface AFI :

It is difficult to present an identification in 2020 without some algorithmic tools. They do not help in a decisive way, but they are useful as an additional green light. The face recognition algorithmic minimum match is not a sufficient condition but certainly a necessary condition of the identification. The match being delivered as a number between 0 and 100, we can consider 70 as a minimum necessary result.

The portrait “DAG” was anonymously submitted to the Artificial Intelligence of Betaface free demonstration API, together with one painting “EAD” and four confirmed photographic portraits “VR1”, “VR2”, “VR3”, “VR4”. The results in number are :

  • The painting “EAD” matches best with “DAG”, “VR4”, then “VR3”, “VR1” last “VR2”
  • “VR1” matches best with “VR3” and “VR2”, then “EAD”, lasts “VR4” and “DAG”
  • “VR2” matches best with “VR1” and “VR3”, then “EAD”, “DAG” and last “VR4”
  • “VR3” matches best with “VR1” and “EAD”, then “VR4” and “DAG”, last “VR2”
  • “VR4” matches best with “DAG” and “EAD”, then “VR3”, “VR1”, last “VR2”

93 % is more than 80 % and “DAG” gets decent results in the matching game, on a par with confirmed paper portraits of the period.

Now we will consider complementary classical forensic research discussing four points:

  • The 1830 scar on the left eye
  • The moles on the face
  • The hands of the sitter and his general attitude
  • The presence of an elegant tie pin
  • The backdrop, or the absence of backdrop

The 1830 scar on the left eye

1830 was a troubled time; the École polytechnique was the focus of riots; the students were armed with guns. By suddenly raising his weapon, Regnault reached a lamp whose glass, shattered by the shock, fell and penetrated his left eye, making him fear the loss of the organ and making, in any case, long rest necessary.

We compare the sitter of “DAG” with the painted portrait “EAD”, the left eye appears for us on the right side of the face.

We cannot find the exact date when“the explosion of a matras full of boiling mercury had ploughed his face”. During a period, he would avoid self-portraiting with burning scars. In 1846, his face looks much older, then his skin seems softer, but retouching negatives was a current practice.

The moles on the face

We notice the sitter of “DAG” has a mole on the left side of the upper lip. We compare with “VR2” and “VR3”

We compare also the lips, philtrim (depression below the nose), the accentuated depression below the lower lip and the dimple on the chin.

The compare hands of the sitter and his general attitude with “EAD”, VR1″ and “VR2”

We compare the length of the fingers

An elegant tie pin

“A tie pin is an old fashion accessory born in the middle of the 18th century in England and adopted in popular France, especially in the 19th century, it was gradually replaced by the tie pin, more practical for the narrowing of the fashionable tie, called “la régate”. (Wikipedia)

The backdrop, or the absence of backdrop

French daguerreian portraits with a blank background are rare, mostly created in scientific circles, especially after the very popular introduction of painted backdrops by Claudet in his London portrait studio at the end of 1841.

How can we explain that the name of Victor Regnault is still in the shadow of the history of photography ? The answer is given also by the biographer :

“Well, in 1870, during the Siege of Paris, a brutal hand destroyed at Sèvres, occupied by the enemy, all his notes and every single instrument in this laboratory. Nothing seemed to have changed in this asylum of science, and everything was destroyed. All that had been done was to break the rods of the thermometers or the tubes of the barometers and manometers, which had become, through their participation in the most important experiments of the century, veritable historical monuments; for the balances and other precision apparatus, it had been enough to hammer the fundamental parts out of shape; the registers and manuscripts, gathered in heaps, had been delivered to the flames and reduced to ashes.

Ten years of work, and hundreds of results that natural philosophy will always regret and will not find again, had disappeared; a cruel occurence for which history offers no other example! We can excuse the Roman soldier who, in the fury of an assault, massacred Archimedes; he did not know him. But, Regnault said with a sad smile as he showed me his disgraced instruments, this work of destruction is the work of a true connoisseur! and this dust,” he added, pushing back with his feet the ashes left by his manuscripts, “is what remains of my glory! » ( J.-B. Dumas, Éloge)

Victor Regnault. Gardens at St.-Cloud, large calotype, c. 1853 (Met Museum)

Victor Regnault’s contribution to the history of photography deserves recognition. The destruction of his notes by Prussian soldiers in 1870 is not the only reason of his modest presence in publications. Constantly applying his own principles to the observation of precise facts and the search for empirical formulas, he promoted the invention and development of photography without ever putting himself forward.

Elements of chronology

1839 (March). Regnault describes the physicochemical principle of the daguerreotype and publishes its explanations in an article studied by many scientists including Herschel and Talbot.

1840. He receives, tests and experiments all the samples sent by the inventors to the Academy of Sciences from 1840 onwards.

1843. He receives and encourages Talbot in an attempt to develop the calotype in Paris — L’Ecole Normale de Photographie …

1846-1847. He scientifically supports and helps Blanquart-Evrard to create his photographic printing house in Lille.

1848. He receives Gustave Le Gray, scientifically explains to him the photogenic qualities of beeswax and the importance of his discovery of the wax paper process, then has him and his friend Mestral appointed to the great adventure of the Mission Héliographique.

1849. Regnault collects early prints, annotating for example the first Le Gray’s experiments with glass negatives.

1851. Regnault, Delacroix, Ziegler and various pioneers found the Société Héliographique and the mythical newspaper La Lumière.

1852. Appointed by the Emperor to be in charge of an industrial complex in Sèvres, he improves his calotype practice, creating a real aesthetic school.

1855. He is appointed the first President of the French Society of Photography and supports the entry of Photography among the Fine Arts.

1856. His health accident in coincides with a decline in the position of artist photographers in French society.

Elements of Bibliography

J.-B. Dumas, Éloge de Victor Regnault, membre de l’Académie des sciences, lu dans la séance publique annuelle du 14 mars 1881 (Annales des Mines, tome XIX, 1881

Sébastien Poncet, Laurie Dahlberg. The legacy of Henri Victor Regnault in the arts and sciences.International Journal of Arts and Sciences, 2011, 4 (13), pp.377-400

Larry Schaaf, Édouard de Saint-Ours, Doing the Django – and Finding Talbot’s Calotype School in 1843 Paris, https://talbot.bodleian.ox.ac.uk/2018/05/18/doing-the-django-to-find-talbots-calotype-school-in-1843-paris/

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