Chlorine bleaching: a gas instead of a meadow and the sun
The bleaching of textiles with chlorine gas, an operation which before took weeks of laying the cloth out on grass under the sun. Begun as a test of the oxygen theory, it turned out to be an applied technique.
The French chemist Claude Berthollet in 1785 was performing experiments on 'dephlogisticated marine acid', that is, chlorine, to test Lavoisier's theory, and observed that the gas had bleaching properties; he then looked for a simple way of applying them to cloth. He had taken the post of inspector of dye works and director of the Gobelins on Macquer's death a year earlier, in 1784.
Unlike contemporaries such as Watt he did not patent it. The name 'Javel water' remained from the works that invited him to demonstrate the method gratis and then tried to patent it themselves. In Berthollet's own words, he was driven chiefly by the humanitarian ideals of the Encyclopedists.
Why this date
The axis value is 1785: according to the DSB (entry by Kapoor) it was in 1785 that Berthollet performed a large series of experiments on dephlogisticated marine acid, that is, chlorine, and in the same year became the first major convert to the oxygen theory. The exact date of publication of the bleaching process and the date of the industrial introduction of Javel water could not be verified in the sources available, so the label gives an interval rather than a year.
What it grew from
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Inspector of dyeing: an academy chemist put in charge of colour
influenced · Confidence: medium
Bleaching and dyeing were the two fields in which the Academy of Sciences, on Colbert's plan, conducted research, and Berthollet took up chlorine after succeeding to the post of inspector of dye works on Macquer's death in 1784; he himself explained his interest partly by that service.
Dispute: Kapoor weakens the link in the same sentence: the Gobelins affiliation, he says, only partly prompted Berthollet, while Berthollet himself insisted that his chief motive was the humanitarian ideals of the Encyclopedists. The source that asserts the link at once says it was not the decisive one.
Link sources
- Delamare F. «Teindre au bleu de Prusse, une aventure française», Technologie et Innovation 4 (4), 1-15 (2019), 3 Verified 5 Oct 2026
Blanchissage et Teinture, c'est dans ces deux domaines que l'Académie royale des Sciences, inspirée par Colbert, va lancer des recherches afin de détecter les procédés les plus efficaces employés, de les étudier, les améliorer et les recommander.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 5 Oct 2026
In 1784, on Macquer's death, he was appointed inspector of dye works and director of Manufacture Nationale des Gobelins.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026
partly prompted by his affiliations with Gobelins, but chiefly (as he often insisted) by the humanitarian ideals inculcated in him by the Encyclopedists
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.
- Delamare F. «Teindre au bleu de Prusse, une aventure française», Technologie et Innovation 4 (4), 1-15 (2019), 3 Verified 5 Oct 2026
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Oxygen theory of combustion and "Réflexions sur le phlogistique"
influenced · Confidence: high
The experiments of 1785 on dephlogisticated marine acid, in which the bleaching action of chlorine appeared, were performed by Berthollet in order to test the correctness of Lavoisier's oxygen theory, and as a result of the same experiments became the first major chemist to accept the oxygen theory, and then for the first time himself declared phlogiston a useless hypothesis.
Dispute: Kapoor says that the chlorine experiments were undertaken to test the oxygen theory, and separately that chlorine turned out to have bleaching properties, but does not join the two statements in one sentence. Moreover Berthollet did not accept oxygen as the principle of acidity, and chlorine itself was misunderstood within the oxygen theory as oxygenated muriatic acid: the theory supplied the occasion and the name, not the explanation.
Link sources
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026, quotation assembled from fragments
In 1785, after he had set out to test its correctness by performing a large number of experiments on 'dephlogisticated marine acid' (chlorine), Berthollet explicitly stated for the first time that 'this principle, which Stahl had ingeniously imagined in order to explain a large number of phenomena...had at last become a useless hypothesis.'
- Crosland M. «Berthollet, Claude Louis», Complete Dictionary of Scientific Biography (via Encyclopedia.com) Verified 20 Sep 2026
He was the first major convert to Lavoisier's oxygen theory (1785) despite justifiable disagreement on the idea of oxygen as the principle of acidity.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026
Having observed that chlorine had bleaching properties, he wanted to find a simple technique for introducing it as a bleaching agent for textiles.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong. "Assembled from fragments" means the words do not stand together on the page: we found each fragment separately and joined them with an ellipsis.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026, quotation assembled from fragments
Node sources
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 5 Oct 2026
In 1784, on Macquer's death, he was appointed inspector of dye works and director of Manufacture Nationale des Gobelins.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026
Having observed that chlorine had bleaching properties, he wanted to find a simple technique for introducing it as a bleaching agent for textiles.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026, quotation assembled from fragments
In 1785, after he had set out to test its correctness by performing a large number of experiments on 'dephlogisticated marine acid' (chlorine), Berthollet explicitly stated for the first time that 'this principle, which Stahl had ingeniously imagined in order to explain a large number of phenomena...had at last become a useless hypothesis.'
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026
Unlike such contemporaries as Watt, who amassed large fortunes from their industrial inventions, Berthollet published his technique for the bleaching of textiles by chlorine without bothering to patent it.
- Kapoor S. C. «Berthollet, Claude Louis», Dictionary of Scientific Biography Verified 20 Sep 2026
they invited Berthollet to demonstrate the application of his method-which he did gratis-and then tried to patent his discovery of the bleaching liquid, calling it lye de Javelle.
- Delamare F. «Teindre au bleu de Prusse, une aventure française», Technologie et Innovation 4 (4), 1-15 (2019), 3 Verified 5 Oct 2026
Blanchissage et Teinture, c'est dans ces deux domaines que l'Académie royale des Sciences, inspirée par Colbert, va lancer des recherches afin de détecter les procédés les plus efficaces employés, de les étudier, les améliorer et les recommander.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong. "Assembled from fragments" means the words do not stand together on the page: we found each fragment separately and joined them with an ellipsis.