Just a Grand Duke who Loves Chemistry. Peter Leopold of Habsburg-Lorraine (1747–1792) and his Chemical Cabinet at the Imperial and Royal Museum of Physics and Natural History

This article dealt with the history of the chemical cabinet established by the Grand Duke of Tuscany, Peter Leopold of Habsburg-Lorraine (1747–1792), at the Imperial and Royal Museum of Physics and Natural History in Firenze during his regency. To achieve this goal, it investigated untapped archival sources (e.g., administrative and commercial documents, minutes, correspondences, inventories) concerning the museum management from its foundation in 1775 to the departure of the Grand Duke for Vienna to be crowned as Holy Roman Emperor Leopold II in 1790. The article analyzed the chemical cabinet’s manuscript catalog, whose entire transcription is presented in the Supplementary Information Files. The work then examined the connections between the activities performed at the chemical laboratory and Peter Leopold’s interests in experimental chemistry. Concerning this research question, the scientific relationship he held with the naturalist Giovanni Valentino Mattia Fabbroni (1752–1822) – Vice-director and then Director of the Imperial and Royal Museum of Physics and Natural History – who helped the Grand Duke navigate all aspects of his interests in chemistry and natural sciences, was also discussed.


Introduction
Writing about a notable historical figure such as Peter Leopold of Habsburg-Lorraine (1747-1792) is not an easy task. So, it is not by chance that Soll stated that "there is no single way to characterize Peter Leopold. His approach to intellectual life, philosophy, and governing were pragmatic, eclectic, and a mix of his various influences". 1 In fact, it is difficult to account for the life 2 of a man who was the ninth son of Francis I (1708-1755) and Maria Theresa of Austria (1717-1780), brother of Joseph II (1741-1790) and Marie Antoinette (1755-1763), 3 Grand Duke of Tuscany from 1755 to 1790, and the next-to-last Holy Roman Emperor (Leopold II) from 1790 to 1792, year in which he suddenly died from pleurisy at the age of 44 years. 4 But that is not all. Peter Leopold was a Jansenist and an enlightened despot, 5 whose concrete projectsas stated by Maran, Castellini, and Bisman-6 reformed the administrative, managerial, organizational, judicial, 7 and economic aspects of social and cultural life in the Grand Duchy of Tuscany. In this regard, Sarti found that these amendments "transformed Tuscany into a model state", 8 while Maran et al. underlined how the analysis of the municipalities' reform contributed to a better understanding of today's decentralization by governments in the context of the new public management. 9 However, a complete survey of Peter Leopold's reforms of Tuscany is out of scope here, and the reader is referred to the literature for further details. 10 The principal aim of this study is to detail and analyze the history of the chemical cabinet Peter Leopold established at the Imperial and Royal Museum of Physics and Natural History through the investigation of the scientific relationship the Grand Duke held with the naturalist and Museum's vice director Giovanni Valentino Mattia Fabbroni (1752-1822) 11 together with the examination of the laboratory's catalog. 12 The latter unpublished source is preserved at the Museo Galileo's library, whose archival fund on the history of the Imperial and Royal Museum of Physics and Natural History 13 holds various documents that were investigated to achieve the goals of the present paper.
The existing literature on the Imperial and Royal Museum of Physics and Natural History is extensive and focuses mainly on its collections and history. 14 The Museum, established by Peter Leopold's motu proprio on 22 February 1775, was not only a place to gather and preserve the naturalistic and scientific collections inherited by the Medici family 15 and the Accademia del Cimento 16 but also acted as a research center to promote useful knowledge in the service of the public good. 17 In this regard, Contardi underlined how the museum collections were open to all and organized to encourage a visitor's self-instruction through the display of explanatory labels. 18 However, the collections did not comprise only the specimens and instruments belonging to the Medici family and the Accademia del Cimento. Still, they were constantly enriched by new acquisitions 19 promoted by Peter Leopold, together with the instruments, preparations, and objects 20 realized at the various museum workshops. 21 Among these, there was the chemistry cabinet that was established to represent, according to both Felice Fontana (1730Fontana ( -1805 and Giovanni Fabbroni, one of the most advanced research centers at an international level. It encompassed, in addition to the standard equipment like flasks and bell-jars, diverse pneumatic pumps 22 together with a workbench -realized by the woodcutter Francesco Schmidt (dates uncertain)-23 belonging to Peter Leopold. It was openable with a slate working surface for experiments. One of the three cavities in the workbench is linked to a bellow operated by pedals useful for calcination and combustion operations. Various shelves allowed to store glassware, tiny bottles, and chemical compounds (Fig. 1). In this regard, Scorrano et al. analyzed 38 samples using X-ray fluorescence, X-ray diffraction, gas chromatography-mass spectrometry, IR spectroscopy, thermal analysis, and chemical tests.
According to the authors, most of the compounds were employed in textile manufacturing, while the remaining represented both chemicals helpful in improving wine production and substances of apothecary interest. 24 Many historians have connected the investigation on the workbench to the work of Huber Franz Hoefer (1728-1795) at the court apothecary, as well as to the research the Grand Duke patronized on water 25 and hot springs 26 . While recent studies have linked Peter Leopold's interest in chemistry to mineralogy, mining science, and mineral collecting. 27 However, so far, there has been little discussion about the involvement of Peter Leopold in the experiments being conducted at the chemistry cabinet and the organization of the chemical laboratory. In the following pages, the analysis of untapped archival documentation will generate fresh insights into these subjects.

Materials and Methods
As mentioned in the Introduction Section, this study investigated the historical documentation that described both Peter Leopold's interest in chemistry and the chemical cabinet he established at the Imperial and Royal Museum of Physics and Natural History. The documentation covers a period from the museum's foundation in 1775 until the end of Peter Leopold's regency as Grand Duke of Tuscany in 1790. Exceptions were documents about the chemical cabinet covering a period up to 1807. The materials were analyzed according to the standard archival research methods illustrated, for example, in Ventresca and Mohr. 28 The benefit of this approach is providing access to data that would not otherwise be known. Furthermore, the presentation of the archival documents according to a schematic organization facilitates their use as a resource for scholars interested in the history of chemistry in 18 th -century Italy.

Bonding in chemistry: Peter Leopold and Giovanni Fabbroni
One of the first research questions that come to mind is: did Peter Leopold attend the Imperial and Royal Museum of Physics and Natural History? Or the museum's establishment was, as stated by Solomon,29 just a result of the European Enlightenment ideas? If, on the one hand, it is beyond dispute that the museum foundation was a consequence of Peter Leopold's reformism, i.e., the promotion of science as an instrument of public utility, 30 fusible salts of urine (i.e., the complex of salts present in human urine, which may indicate ammonium sodium phosphate or sodium ammonium chloride) and diverse essential oils (e.g., chamomile and cardamon). 35 Since then, Fabbroni bought various boxes of Baumé's preparations until 1788. 36 One of the last products Fabbroni purchased from Baumé at Peter Leopold's request was a supply of pâte de guimauve, i.e., a demulcent lozenge prepared from the root of Althea officinalis. 37 On Tuesday 19 May 1788, Mannucci advised that "His Royal Highness ordered Fabbroni to write to Monsieur Baumè to send him, as soon as possible, 12 pounds of pâte de guimauve within a small cup, so that it would not be broken". The order had to be of particular urgency since Mannucci sent the same note twice on Friday 22 May 1788. 38 At the end of June, Fabbroni noticed that the box was just arrived in Firenze, hoping that it would be delivered at the Royal Chamber soon. 39 Unlike the previous shipments, the pâte de guimauve was transported from Paris to Firenze via Genova, and its delivery was in the care of the courier Francesco Maria Vignolo (dates uncertain). 40 On the same note, Fabbroni gave positive news about sending 17 pounds and 2 ounces of Venus crystals (copper acetate) that had been bought from Bertrand Pelletier's (1761-1767) laboratory. 41 The products sold by Pelletier had already aroused the Grand Duke's interest in the past. As an example, on 6 April 1787, during one of his stays in Pisa, Peter Leopold charged his Intimate Secretary Ranieri Fulger (dates uncertain) writing Fabbroni to inquire about the essences and essential oils sold by the Parisian apothecary. 42 Peter Leopold was then very interested in the work of another French chemist, Jean Antoine Claude Chaptal (1756-1832). 43 In an undated document, Mannucci referred to Fabbroni that the Grand Duke had heard the news about a "Monsieur Chaptal who has a big store in Montpellier selling all kinds of chemicals, acids, and drugs of excellent quality at a meager price". Mannucci then said that "His Royal Highness will appreciate Fabbroni writing to some of his correspondents to know whether this is true or not. In case of a positive response, His Royal Highness will be pleased to receive a note on all the products he sells with their respective prices". 44 Fabbroni wrote to Chaptal 45 and the latter sent back a descriptive letter 46 on both the compounds he produced and the procedures he followed for realizing the crystallization of vitriol oil. In this regard, it has to be said that Chaptal sent Fabbroni letters like this more than once. For example, he illustrated the products he sold in Montpellier and his research methods in a missive dating 24 December 1786. This document shows on the top right of its first page a Fabbroni's brief remark in which he noted that the response was sent on 15 January 1787. He also noticed to have rewritten to the French chemist on 22 February 1787 because he was waiting for a box of chemicals that was not delivered yet. Later, Chaptal would have informed Fabbroni about his chemical products and his upcoming scientific publications. This is the case of a letter, partially gone missing, in which he noticed the forthcoming release of a treatise in two volumes on modern chemistry (i.e., Elements de Chemie, 1790). 47 On 10 November 1786, Fabbroni sent a request for chemicals to Chaptal following a detailed list Peter Leopold had sent to him some days earlier. 48 The content of the list is reported in Table 1 A second list, containing the request for other three chemicals (e.g., six ounces of phosphor, six ounces of pyrophorus, 50 and one pounds of tartar acid) to buy from Pelletier's laboratory, was attached in a letter Peter Leopold sent to Fabbroni from Pisa on 17 January 1787. 51 The delivery of the products coming from Chaptal's store in Montpellier  Secretary, so it could be placed in a suitcase that was ready to be shipped to Pisa. 55 Coming back to the order of chemicals delivered by the French apothecary Chaptal in March 1787, Peter Leopold gave away the butyric antimony to the chemistry cabinet. He advised Fabbroni that the products' jars were extremely fragile and had to be handled with highly caring. 56 One of the last orders Fabbroni commissioned to Chaptal dated to mid-January mid-March 1788. 57 As mentioned before, Fabbroni was not only an agent for purchasing chemicals but also a mentor who guided the Grand Duke through the path of chemistry. For example, while he was experiencing cinchona, Peter Leopold asked Fabbroni if its extract could be reverted to gel in a brass pot, in a copper and silver evaporator, or if it was necessary to store the compound in an earthenware evaporator. 58 Fabbroni was also Peter Leopold's mentor for mineral chemistry and its application to mining science. In this regard, after visiting the Habsburg iron mines in 1779, Peter Leopold realized that the Tuscan iron deposits were not adequately exploited. Therefore, he asked Thaddeus Rauscher (dates uncertain), a mining expert in Carinthia, to come to the Grand Dutchy of Tuscany to evaluate the ore processing.
Fabbroni discussed the results of Rauscher's investigations in two reports in 1780. In the first document, the events concerning these inspections were summarized. Fabbroni stated that two experts from Carinthia arrived in September to check the quality of the iron ores and any abuses committed by the local mining administrations. However, one of the two men left the country promising to return after a few days, while the other remained in Firenze without continuing the work. New mining experts arrived from Carinthia, and after analyzing some ores extracted in Maremma, they came to different conclusions about the iron processing systems in use. The first one stated that the defects in ironworking originated from the small amount of coal used in processing the raw materials. The second expert thought that they were caused by an insufficient quantity of iron ores being processed. 59 So ends the first document. In the following Report on the iron mines in the Grand Duchy of Tuscany and the sampling made by Taddeo Glauscher of Carinthia in 1780, 60 Fabbroni disagreed with the opinions of the foreign mining experts, saying that "they were not aware of the progress in iron processing made outside their homeland". As an example, he stated that the three furnaces employed in the smelting were necessary because of the samples' size, while the iron produced in Livorno, whose excessive malleability could be easily corrected, could also be used to manufacture nails and In the following sub-section, the organization of the chemistry cabinet is described through the examination of its catalog -comprising instruments, books, and compounds, some of which belonged to and were made by Peter Leopold-and information is also given on the destiny of the cabinet after the Grand Duke left Firenze in the summer of 1790 to be crowned as Holy Roman Emperor Leopold II.

A Grand Duke at Work: Peter Leopold's Chemistry Cabinet
The organization of the chemistry cabinet is illustrated in a 100-pages manuscript entitled Laboratorio di Chimica (Chemistry Laboratory), which is preserved at the Museo Galileo's Library. 65 were kept, and each compound was preceded by the symbols "•" or "x", which probably indicated its presence or lack ascertained during an inventory. The chemicals were then grouped according to the shelves where they were stored, as shown in  The following catalog's section concerned the chemicals obtained by processing the "three Kingdoms of Natures" (i.e., animals, plants, and minerals), which were housed in the second of the three rooms designed to accommodate the chemical cabinet within the Imperial and Royal Museum of Physics and Natural History. 66 In this regard, it has to be noted that most of these compounds were in poor conservative conditions since they were evaporated or altered and need to be restored. The preparations' list has been transcribed in Supplementary Information Files I-IV, while some information of potential interest resulting from the transcription activity is reported below.
In a closet on the left of the room were substances of animal and/or human origin (e.g., cow's milk serum, gelatinous part of dried human blood, urine salts) for a total of 129 preparations. Some of these compounds' descriptions are followed by the letters "MB" in red ink, while the red-ink string "O-KI-AO-" is placed before the "donkey glue as prepared by Chinese people" (Colla d'Asino come preparate dai Cinesi). Subsequently, there were the plant chemicals comprising 295 preparations.
Among them, seven samples were preserved without their containers. 67 It is then interesting to note that diverse samples of honey were listed as preparations of vegetable origin, and one of these varieties (e.g., honey without phlegm, Miele sflemmato in the original text) was marked with the redink letters "MB". It is also noteworthy to highlight the presence of two kinds of milk sugars (e.g., impure sugar milk, Zucchero di Latte impuro; white sugar milk, Zucchero di Latte bianco) as well as the numbers "II" and "III" to indicate two different samples of rectified ether. Numbers "2", "2.3", and "3" were used to show respectively a sample of turpentine essential oil (Olio essenziale di Terebentina), and two samples of turpentine oil (Olio di Terebentina). The only compound that was cataloged as a poison was a sample of Ticunas, i.e., an American poisonous substance whose effects were studied by Felice Fontana in an essay published in 1780. 68 On the right side of the room, a closed kept the compounds that were realized by processing minerals for a total amount of 436 samples.

Results and Discussions
This study aimed to assess the history of the chemical cabinet at the Florentine Imperial and Royal Museum of Physics and Natural History during the Grand Duke Peter Leopold's regency. To achieve this goal, the catalog of the chemical cabinet was analyzed, and the entire manuscript text was transcribed in the Supplementary Information Files. The investigation showed that 1534 items were kept in the cabinet between 1780 and 1807. Among them, there were 1374 chemicals. What is interesting about the data is that 950 compounds belonged to Peter Leopold and therefore, they were Peter Leopold during the meeting he had with the Grand Duke at the end of 1778. 75 In this regard, it has to be noted that the sample made by Peter Leopold was stored on Shelf no. VIII, which was entirely devoted to the preservation of dyes and varnishes for painting, coating wood, gilded brass, and other minerals. Among the 92 preparations, there were two samples of Lac Martin: the one prepared by Peter Leopold and a second one briefly described as "Bechi's Lac Martin". 76 Unfortunately, the catalog provided neither further information on Peter Leopold's preparation nor on the Bechi's one.
Nevertheless, the latter could be possibly identified with Antonio Bechi (dates uncertain), a member of the Florentine Confraternity of the Misericordia and an impresario who established a theater in Via di Porta Rossa in 1760. 77 In the current state of research; it is neither possible to affirm nor deny that the Bechi who prepared the second Lac Martin sample was Antonio Bechi. And if this was the case, neither had he ever met Peter Leopold to explain the varnish preparation. However, this is a hypothesis valuable to be explored in further studies.

Another striking observation emerging from comparing the chemicals' inventory belonging to Peter
Leopold is that various preparations were comprised in the orders the Grand Duke received by the diverse French apothecaries in the 1780s. As expected, not all the compounds bought through the years have been cataloged (e.g., the pâte guimauve) because they were used to perform experiments or make other preparations, such as the radical vinegar of Venus, which was based on Venus crystals.
However, Table 1   Subsequently, the combination of the findings presented in this study raises the possibility that Peter Leopold's interest in chemistry, although influenced by the cultural context in which he lived, could be genuine. For example, he carried out experiments on the diverse phases of matter and performed personal investigations outside the chemistry cabinet, as shown by the orders of chemical products he asked to be delivered in Pisa with urgency at the end of 1786.
About the remaining parts that constituted the catalog of the chemical cabinet, it was considered not to explore them further than the materials presented in the previous section since these inventories are linked neither to Peter Leopold nor to the activities he carried out at the chemical cabinet, covering the volume a period up to 1807. Regarding the inventory of the books kept in the chemistry cabinet, it is interesting to outline that on 14 May 1789, Francesco Favi informed Fabbroni of the publication of Lavoisier's Traité élémentaire de Chimie and of the first volume of the Annales de Chimie. Favi then advertised to have shipped the books by courier to Fontana's address and asked whether he was to send the ongoing annals or not. 84 According to inventory, the museum acquired for the library of the chemical cabinet both the volumes of Lavoisier's Traité élémentaire de Chimie and the first ten issues of the Annales de Chimie.

Conclusions
The present study aimed to examine the history of the chemical cabinet at the Imperial and Royal