This research was suggested by Tony Travis of the Sydney M. Edelstein Center of the Hebrew University, Jerusalem, and initiated during my stay there as Senior Research Fellow, March—June 1990. Parts of this paper were presented at the International Workshop on the History of Chemical Technology, Jerusalem, May 1990, at the Conference of Technological Development and Science in the 19th and 20th Centuries, Eindhoven, November 1990, and at the 'First Minerallcontor', Veszprem, August 1991.

I would like to thank Tony Travis, Elisabeth Vaupel and Ernst Homberg for their help and criticism, and the archivists of BASF AG (Ludwigshafen) and the Deutsches Museum (Munich) for allowing me to make use of the resources under their care.

¹ The history of dyestuffs chemistry was recently treated by Stoltz, R., Schriftreihe f.Geschichte der Naturwissenschaften, Technik und Medizin (1980), 17, (2), 84–101; (1981), 18, (1), 62–83; (2), 29–48Google Scholar, and by Hornix, W. J., ‘De ontwikkeling van de kleurstofchemie van 1850 tot 1887’ (The development of dyestuffs chemistry 1850–1887), in van den Belt, H., Gremmen, B., Homburg, E. and Hornix, W., De ontwikkeling van de kleurstofindustrie (The development of the dye industry), final report of a Science and Society project, Nijmegen, 1984, 49–104.Google Scholar

² The handbooks of dyeing and printing and those of chemical technology of the period aimed to be up-to-date with respect to the preparation and use of coal-tar dyes. There are monographs dealing with certain well-defined classes of dyes, which sometimes give much technological information. The dictionaries of chemistry and chemical technology of the period contain highly relevant articles by experts in the field.

British patents on synthetic dyes are found in class 2 (acids and salts, organic and other carbon compounds, including dyes), French patents in class XIV, 2 (Arts chimiques, Matières colorantes), and, after 1877, German patents in class 22 (Farbstoffe, Firnisse, Lacke). These patents on synthetic dyes are about processes leading to colouring matters, not about apparatus. Only extraction processes for natural dyes were protected by patents in which special appliances were described. However, there are patents about apparatus relevant to artificial dyestuff production in quite different classes. Of great help are: for British patents the Abridgments of Specifications, published at the Patent Office; for French patents the compilation Tables des Volumes …, and the Subject-Matter Index, Patents for Inventions (Brevets d'invention) Granted in France from 1795 to 1876, inclusive, translated, compiled and published under authority of the Commissioner of Patents, Washington, 1883; and for German dyestuffs patents the critically and systematically analysed compilation of Friedländer, P., Fortschritte der Theerfarbenfabrikation und verwandter Industriezweige, 1877–1887, Berlin, 1888Google Scholar, Bis idem., 1887–1890, Berlin, 1891, etc.

Technological source material on dyes can be found in the technical journals with, after 1855, an invaluable entrance provided by Wagner's Jahresbericht der chemischen Technologie. The main difficulty with the technological literature is that references are not abundant, and consequently much effort has to be invested in deciding what is original and what is derived.

An important source for industrial information consists of the reports on the international exhibitions, generally written by experts in the field since they were often members of the jury of exhibitions. The reporters had excellent personal contacts and were free and generous in the communication of their knowledge. The reports of exhibitions held in 1862 (London), 1867 (Paris), 1873 (Vienna) and 1878 (Paris) play a crucial role in this story.

These publications will be cited in so far as they give new information. Handbooks, monographs, dictionaries and encyclopedias are also indispensable as guideposts to new technological information.

³ See Farrar, W. F., Endeavour (1974) 23, 149–55CrossRefGoogle Scholar, who refers to Guinon, N., Revue scientifique (1849), 5, 233Google Scholar (not seen); and Girardin, J., Leçons de Chimie Élémentaire appliquée aux Arts industriels, 4th edn, Paris, 1861, ii, 599Google Scholar, fig. 515. Boboeuf, French patent no. 15271 of 17 March 1856.

⁴ Perkin, W., British patent no. 1984, 26 08 1856Google Scholar; French patent no. 20326, 8 April 1858.

⁵ The earliest appliances for the nitration of benzene are described in Girard, C. and de Laire, G., Traité des dérivés de la houille applicables a la production des matières colorantes, Paris, 1873, 251–5Google Scholar. Mansfield's British patent no. 11960 of 11 November 1847 is a 50-page illustrated treatise on manufacturing ‘spirituous substances and oils’ and ‘applications to the purposes of artificial light’. The nitration of benzene is only a minor aspect of his patent. An illustration of an earthenware version of an apparatus for the nitration of benzene is given by Reimann, M., Technologie des Anilins, Berlin, 1866, 13CrossRefGoogle Scholar. See also Travis, T. (A. S.), ‘Early intermediates for the synthetic dyestuffs industry’, Chemistry & Industry, 15 08 1988, 508–14Google Scholar; and Travis, A. S., ‘Perkin's mauve: ancestor of the organic chemical industry’, Technology and Culture (1990), 31, 51–82.CrossRefGoogle Scholar

⁶ Perkin, W. H., J. Chem. Soc. (1896), 69, 609.Google Scholar

⁷ Perkin, W. H., J. Soc. Arts (1869), 17, 99–105, 109–14, 121–6Google Scholar. The apparatus is shown in fig. 1, p. 101. Girard, and de Laire, (1873), op. cit. (5)Google Scholar, plate II, fig. 1, is more detailed than Perkin's figure.

⁸ The earliest evidence consists of drawings of a reactor of about 50 gallons capacity, fitted with a power-driven stirrer, and delivered in 1861 by a London firm to Roberts, Dale & Co. W. Pillmer to Roberts, Dale & Co., Caro Nachlass, Special Collection, Deutsches Museum (uncatalogued item).

⁹ Perkin, , op. cit. (7), 104.Google Scholar

¹⁰ A pressure boiler for dye extraction of Bohra is reproduced in Wedding, , Verhandlungen des Vereins zur Beförderung des Gewerbenfleisses in Preuszen (1855), 113–14, plate XVI.Google Scholar

¹¹ Hofmann, A. W., de Laire, G. and Girard, C., Report on the colouring matters derived from coal tarGoogle Scholar, Appendix of Reimann, M., On Aniline and its Derivatives, revised and edited by Crookes, W., London, 1868Google Scholar, and Girard, and de Laire, , op. cit. (5), 251–8Google Scholar, plate II, figs. 1, 3, 4, 5 (legends pp. 630–1) for the preparation of nitrobenzene, and pp. 330–50, plate II, fig. 2 (legends p. 630) for the preparation of aniline.

¹² The situation is different with respect to the raw material for the preparation of aniline: benzene. The separation of coal-tar components by distillation is the subject of a long series of patents, forming a continuous tradition during the entire period under investigation. The development of coal-tar distillation is closely connected with that of the dyestuffs industry and is a worthwhile subject of a separate chapter of the history of chemical technology.

¹³ Patent statistics derived from the Abridgments of Specifications (1905) op. cit. (2). Marketed products are listed in Schultz, G. and Julius, P., Tabellarisches Uebersicht der künstlichen organischen Farbstoffe, Berlin, 1888Google Scholar, and in Chateau, Theodore, Nouveau manuel complet, théorique et pratique, de la fabrication et de l'emploi des couleurs d'aniline, d'acide phénique, de naphthaline et des homologues de ces substances, etc., Paris, 1868.Google Scholar

¹⁴ French patent no. 22706, 8 April 1859; British patent no. 921, 12 April 1859.

¹⁵ Girard, and de Laire, , op. cit. (5), 551–2.Google Scholar

¹⁶ van den Belt, H., ‘Action at a distance. A. W. Hofmann and the French patent disputes about aniline red (1860–1863), etc.’, in Expert Evidence: Interpreting Science in the Law (ed. Smith, R. and Wynne, B.), London, 1988, 184–209, 263–8Google Scholar; Travis, A. S., The Rainbow Makers. The Origins of the Synthetic Dyestuffs Industry in Western Europe, Bethlehem, Pennsylvania, 1992, chapter 5.Google Scholar

¹⁷ British patent no. 126, 18 January 1860.

¹⁸ Travis, op. cit. (16), chapter 5.

¹⁹ Wurtz, A., ‘Matières colorantes dérivées du goudron de houille’, in Exposition universelle de Londres de 1862 (ed. Chevalier, M.), Paris, 1863, i, 277–308Google Scholar; Reimann, op. cit. (5); Hofmann, de Laire and Girard, op. cit. (11); Reimann, op. cit. (11); Perkin, op. cit. (7); Girard and de Laire, op. cit. (5); Schoop, P., Dinglers polytechnisches Journal (1885), 258, 276–84Google Scholar; Mühlhäuser, O., Dingl. pol. J. (1887), 266, 455–67, 503–17, 547–63Google Scholar; Mühlhäuser, Otto, Die Technik der Rosanilinfarbstoffe, Stuttgart, 1889.Google Scholar

²⁰ Wurtz, , op. cit. (19), 295–6.Google Scholar

²¹ Girard and de Laire, op. cit. (5), plate VI, fig. 1, 2 (legends p. 631), description pp. 568–70.

²² Hofmann, , de Laire, and Girard, , op. cit. (11), 114–15Google Scholar. The indications between brackets are not in the original text.

²³ Girard and de Laire, op. cit. (5), plate VIII (legends on p. 632).

²⁴ Reimann, , op. cit. (11), 43–4, fig. 7, p. 43.Google Scholar

²⁵ Delapchier, , Le Génie industriel (1854), 323–4, plate 128, fig. 9.Google Scholar

²⁶ French patent no. 66635, 20 March 1865 (and several additions), no. 79126, 9 January 1868, no. 93643, 26 December 1871, no. 102197, 12 February 1874. von Wagner, R., Handbuch der chemischen Technologie, 11th edn, 1880, 933–4Google Scholar, fig. 275, gives a description and illustration of Droux's pressure boiler, taken from Droux, Léon, Appareil pour la saponification des matières grasses sous pression et avec agitation mécanique, Paris, 1876.Google Scholar

²⁷ Mühlhäuser, (1889), op. cit. (19), plate IXGoogle Scholar. The same plate shows the two plants for the separation and purification of the components of crude magenta and cerise (not reproduced here).

²⁸ French patent no. 48033, 2 January 1861; British patent no. 97, 12 January 1861.

²⁹ Hofmann, A. W., Proc. Roy. Soc. Lond. (1863), 12, 645–7, 647–8; 13, 6–9, 9–14, 341–7, 485–91.CrossRefGoogle Scholar

³⁰ British patent no. 1291, 22 May 1863; French patent no. 59309, 11 July 1863.

³¹ Hofmann, , de Laire, and Girard, , op. cit. (11), 130–1Google Scholar; Girard, and de Laire, , op. cit. (5), plate X (figs. 1, 2), plate XI (figs. 3, 4), legends pp. 633–4, descriptions p. 599Google Scholar. The closed vessels were charged with 10 kg rosaniline, 5–20 kg alkyliodide, and 10 kg potassium hydroxide, in 100 l alcohol.

³² Turgan, , Les Grandes Usines. Études industrielles en France et à l'étranger, Paris, 1870, ix, 304, 305.Google Scholar

³³ French patent no. 70876, 21 March 1866; British patent no. 1093, 12 April 1866.

³⁴ French patent no. 71970, 16 June 1866; British patent no. 1912, 23 July 1866.

³⁵ C.E., Dingl. pol. J. (1878), 230, 245–51, 351–5Google Scholar; An illustration of such a digester is given in Wurtz, A. (ed.), Dictionnaire de Chimie pure et appliquéeGoogle Scholar (first) Supplement 1880 (no date indicated, however, the relevant ‘fascicules’ are announced in La Revue Scientifique, 2nd series, (1880) 19, 384)Google Scholar. Early illustrations of digesters are reproduced in Das Labaratorium (1835), Heft 36, plate CXLII.

³⁶ For a recent discussion of the alizarin synthesis and the early development of the industrial production of synthetic alizarin see Vaupel, Elisabeth, Carl Graebe (1841–1927) – Leben, Werk und Wirken im Spiegel seines Brieflichen Nachlasses, Ph.D. dissertation, Ludwig-Maximilians-Universität, Munich, 1987Google Scholar. Apart from the interesting historical analysis presented, the publication of Graebe's scientific correspondence and of correspondence berween Caro and Perkin, and Caro and Liebermann in the second volume is an important feature of Vaupel's thesis.

³⁷ See Vaupel, , op. cit. (36), i, 122–41Google Scholar, and Hornix, W. J., ‘The synthesis of alizarin’, paper presented at the XVIIth Congress of the History of Science, Berkeley, 1985.Google Scholar

³⁸ British patent no. 3850, 18 December 1868.

³⁹ Caro, H., Graebe, C., Liebermann, C., British patent no. 1936, 25 06 1869Google Scholar, and French patent no. 88621, 18 January 1870; Perkin, W., British patent no. 1948, 26 06 1869.Google Scholar

⁴⁰ See Dokumente aus Hoechster Archiven, 42 Beginn der Alizarin-Aera, Hoechst AG, 1970: manuscript Dr Riese, ‘Geschichte der Alizarinfabrik’ (12 May–26 June), 46–8; Dr Lucius, E., ‘Diarium’, 07 1874, 61–3.Google Scholar

⁴¹ Perkin, W. H., British patent no. 3318, 17 11 1869Google Scholar, and French patent no. 90007, 16 May 1870.

⁴² Perkin, W. H., J. Soc. Arts (1879), 27, 572–602.Google Scholar

⁴³ Transcriptions of correspondence between Caro and Perkin (i.e. W. H. Perkin, T. D. Perkin, and Perkin & Sons) appear in Vaupel, op. cit. (36). The relevant letters are those dated 21 January till 3 June 1870 (SSDM 2170–2176, 2135–2143).

⁴⁴ Perkin, , op. cit. (42), 594.Google Scholar

⁴⁵ Vincent, C. W. (ed.), Chemistry, Theoretical, Practical and Analytical, Applied to the Arts and Manufactures (no date, c. 1880), i, 518Google Scholar. This dictionary is generally called after its first editer, Muspratt's Chemistry.

The ‘water-tube boilers’ of J. Howard and E. T. Bousfield were protected by a long series of British and French patents. The most relevant are the first patents, British patent no. 226 and nos. 1811, 1866, and the equivalent French patent no. 72393.

⁴⁶ Perkin, , op. cit. (42), 596.Google Scholar

⁴⁷ A concise but informative description of industrial alizarin preparation via anthraquinone is given by Ott, A., Deutsche Industriezeitung (1874), 425Google Scholar; Wurtz, A., Progrès de l'industrie des matières colorantes artificielles, Paris, 1876Google Scholar, is an illustrated separate edition of his contribution, under the same title, to the official French report on the 1873 International Exhibition in Vienna, published 1875; Graebe, C. and Liebermann, C., Das künstliche Alizarin, Braunschweig, 1876Google Scholar, intended for the German report on the same exhibition, was only published separately; interesting technical information and its contemporary theoretical interpretation can also be found in Auerbach, G., Das Anthracen und seine Verbindungen, Berlin, 1873Google Scholar, and in the English edition: G. Auerbach, Anthracen, etc., translated from a revised manuscript by W. Crookes, London, 1877.

⁴⁸ Wurtz, , op. cit. (47), plate IV, fig. 12 (legends p. 192), descriptions, pp. 173–4.Google Scholar

⁴⁹ Auerbach, (1877), op. cit. (47), 152.Google Scholar

⁵⁰ Two letters from Graebe, to Caro, , dated 2 05 and 8 08 1874Google Scholar (SSDM 1987, 1988) and a letter from Liebermann to Caro, of 12 07 1874Google Scholar (SSDM 2094) clarify Caro's influence on the contents of Graebe and Liebermann (1876).

⁵¹ Perkin, , op. cit. (42).Google Scholar

⁵² Graebe, C., Annalen der Chemie (1880), 202, 19–31.CrossRefGoogle Scholar

⁵³ The most informative source is Kopp, A., ‘Anthracène et alizarine artificielle’, Moniteur Scientifique (1878), 20, 1147–68Google Scholar, which is a part of his report ‘L'industrie chimique à l'Exposition universelle de 1878’ in this periodical. Graebe, C. and Liebermann, C., Moniteur Scientifique (1879), 21, 394–428Google Scholar is a translation into French of their essay Das künstliche Alizarin of 1876, supplemented with new information. The article ‘Alizarine artificielle (Industrie)’, of Kopp, A. and Girard, C., in Wurtz (1880), op. cit. (35), i, pp. 93–101Google Scholar, leans heavily on Kopp's Moniteur Scientifique article and on Wurtz's (1876), op. cit. (47), essay.

⁵⁴ Wurtz, (1880), op. cit. (35), i, fig. 4, 5, p. 95Google Scholar, and fig. 8, p. 100, fig. 8 is reproduced here as Figure 10.

⁵⁵ See Levinstein, I., J. Soc. Chem. Industry (1883), 213–27Google Scholar; Vassart, M. l'Abbé, Étude sur l'alizarine artificielle, Paris, 1887, 70Google Scholar; Bolley, P., Kopp, E., Gnehm, R. and Meyer, R., Die Theerfarbstoffe, Braunschweig, 1895–1897, 1661–86.Google Scholar

⁵⁶ We have the opportunity to note a manufacturer's perspective of early alizarin technology in Carl Glaser, ‘Erlebnisse und Erinnerungen nach meinem Eintritt in die BASF im Jahre 1869’, typescript, Heidelberg, 1921, held at the archives of BASF, Ludwigshafen. During the 1870s Glaser was responsible for the development of the alizarin plant of the BASF.

The main obstruction preventing regular alizarin production at BASF was, according to Glaser, the preparation of the product through fusion of sodium sulphoanthraquinonate with caustic soda. The simple and effective laboratory process could not be scaled up. After almost two years of unsuccessful experimentation, Glaser was informed that Hoechst had obtained good results by using a kind of baking oven in which the molten mixture was heated on trays. Its introduction towards the end of 1871 removed the last hindrance to industrial production. It took another five years (until 1876) before the oxidation involved was uncovered, and the improvement brought about by adding oxidants to the mixture and melting in pressure boilers was introduced. Again the acquisition of ‘classified’ information was essential: a former employee of Gessert informed Glaser that the firm used horizontal high-pressure reactors with stirring appliances and added potassium chlorate.

A similar story can be reconstructed from DrRose, , ‘Alizarinrot oder Entwicklung der Alizarinfabrikation’, in Geschichte und Entwicklung der Farbenfabriken vorm. friedr. Bayer & Co, Elberfeld, in den ersten 50 Jahren, Munich, 1918, 291–6Google Scholar (not published, held at the archives of Bayer AG, Leverkusen).

⁵⁷ Baeyer, A.. Berichte der Deutschen Chemischen Gesellschaft (1871), 4, 555–8, 658–65 (1875), 8, 146–8.CrossRefGoogle Scholar

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⁶⁰ This is based on information in Fischer, E. and Fischer, O., Ber. (1878), 11, 195–201, 612–13, 1079–82, 1598–9, 2095–9; (1879), 12, 791–6, 796–803, 2344–53CrossRefGoogle Scholar; Ann. (1878), 194, 242–303Google Scholar; Doebner, O., German patent (DRP) no. 4322, 26 02 1878Google Scholar; Fischer, O., Ber. (1877), 10, 1623–6CrossRefGoogle Scholar; Doebner, O., Ber. (1878), 11, 2274–7CrossRefGoogle Scholar; and patent statistics derived from Friedländer (1888), op. cit. (2), and market information from Schultz and Julius, op. cit. (13).

⁶¹ Hofmann, A. W., Ber. (1877), 10, 213–18, 1378–81CrossRefGoogle Scholar; Witt, O., Ber. (1877), 10, 654–62; (1879) 12, 259–62CrossRefGoogle Scholar; Griess, P., Ber. (1877), 10, 525–30; (1880), 12, 483–9.CrossRefGoogle Scholar

⁶² Derived from Friedländer (1888), op. cit. (2), and Schultz, and Julius, , op. cit. (13).Google Scholar

⁶³ Bolley, , Kopp, , Gnehm, and Meyer, (1896), op. cit. (55).Google Scholar