Coppers from the Battle of Trafalgar: metallurgical analysis of structural fastenings from the French ships Fougueux (1785-1805) and Bucentaure (1804-1805) (original) (raw)
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Naval metals from mid 18th- to early 19th-century European shipwrecks: a first analytical approach
Historical Metallurgy, 2013
This article gives the preliminary results of a study of metal artefacts recovered from European shipwrecks dating from the mid 18th- to early 19th-century. The analytical approach included optical emission spectrometry (OES), atomic absorption spectrometry (AAS) and infrared spectroscopy (IR) which determined the main constituents and trace element contents of the materials. Based on the latter, and other sources of information, a technological assessment was performed. Such data provides information on the functionality of artefacts, the quality of the alloys and their possible provenance.
The underwater site of HMAV Bounty and the area of the mutineer settlement at Adamstown on Pitcairn Island were investigated archaeologically during a four-month expedition in 1998 and 1999. Due to high energy environmental conditions on the maritime site and human activity associated with collecting or recovering material post the vessel's wrecking in 1790, only 147 artefacts and or concretions remained to be recovered during the maritime excavation. These artefacts consequently represent a unique collection of provenanced material from which a chemical and metallurgical investigation can be undertaken. Comparative analysis was conducted between some copper maritime and terrestrial artefacts to reveal the extent of recycling by the mutineer settlement. Further comparative analysis was conducted between copper artefacts from HMAV Bounty and HMS Sirius (1789), as both vessels were extensively refitted a year apart at Deptford dockyard on the Thames before both departed on voyages to the Pacific. Copper-iron composite objects found on the Bounty wreck-site were identified as Bent's pins which have not been found previously in the artefact assemblage of two contemporary RN vessels excavated in the Pacific.
A case study for scientific research prior to conservation of marine metal artefacts
Journal of Archaeological Science: Reports, 2021
A rare find of a high-status 17th century oval box, retrieved from a shipwreck, provided a unique opportunity to research the construction and finishing layers of an object that is untouched for 350 years. This case study was used to demonstrate the extent of data that can be gained from analytical techniques prior to conservation. The amalgam-gilt brass object was studied by optical and electron microscopy, X-radiography, micro-computed X-ray tomography, neutron tomography, X-ray fluorescence, X-ray diffraction, Rutherford backscattering spectrom- etry, proton-induced X-ray emission and gas chromatography. The results have led to a characterisation of the manufacturing methods used on the box and to a better understanding of the practicality of modern analytical methods and techniques in (maritime) archaeological research.
British Archaeological Reports - International Series, 2014
Introduction (chap. 1): This book presents the research results carried on the metallic artifacts from the sloop-of-war HMS Swift (1770), lost off Puerto Deseado (Province of Santa Cruz, Argentina). The shipwreck –located in 47° 45’ 12’’ South and 65° 54’ 57’’ West– was found by local divers, and it has been subject of archaeological study since 1997 by the Underwater Archaeology Program, under the direction of Dolores C. Elkin, Ph.D. (Argentinean National Research Council and National Institute of Anthropology). In particular, this study was framed in the research line of the ship technology and their social context. State of the Art (chap. 2): Characterization analyses of some historical ship artifacts have proven to be very useful since the 1980’s, especially for the temporal and spatial identification of associated remains, as well as for the study of many technical characteristics (e.g. manufacture methods and alloys). The study of metallurgy from historical ships has received special attention in Argentina during the last ten years, and it is reflected in several research on artifacts recovered from XVIIth-XXth century shipwrecks, which were carried out almost entirely by the Archaeometallurgy Group, under the direction of Horacio M. De Rosa, Chem. Eng. (School of Engineering, University of Buenos Aires). These studies have focused on different fastenings and sheathing, and in less degree in other artifacts such as anchors and minor fittings. Many aspects have been analyzed, including their relative chronology and place of origin, the manufacture processes, the quality of the alloys, and their operability within the original context, as well as the degradation processes after the shipwreck. In this region, the researches on Historical Maritime Archaeology began around 1995. Since then, the main project of the Underwater Archaeology Program has been the study of the HMS Swift. Due to the wreck process and the depositional environment, the site has been preserved in extraordinary conditions. The remains include circa 70% of the original structure; the equipment related to the anchoring, steering and pumping systems; rigging components (including rope); cannons, swivel-guns, and personal weapons; wooden furniture and tools; ceramic, porcelain and glassware; several utensils and organic products related to food and kitchen; parts of clothing and uniforms (shoes and accessories); human remains; and some personal belongings, among others –which are, mostly, under sediment. The main lines of research of the project have been the following: life conditions on board (e.g. diet and health), technology developments (e.g. naval architecture and armament), analysis of biological remains, and natural formation site process. Historical Context (chap. 3): During the 18th century, Western Europe was characterized by deep changes, which had worldwide impact. New social, political, and economical relationships precipitated, and many of them became the pillars of modern society. Given that background, the maritime context occupied an outstanding place regarding the process of configuration and world expansion of the main maritime powers (i.e. Great Britain, France, and Spain). Activities developed through their crafts were crucial –especially concerning the overseas trade and the armed conflicts for the supremacy of the seas. In this regard, the time period that encompasses the precedents and prelude of the first Industrial Revolution was signed by diverse processes of technological innovation, and some of them were strongly related to activities performed in the maritime scenario. In 1770, a small fleet was commissioned to Port Egmont, the British operating base in the Falkland Islands (Islas Malvinas), being one of the ships the sloop-of-war HMS Swift. Early on this year, the vessel was doing some coastal survey, when strong winds forced it to reach the continental coast. After a few days, the crew decided to enter in the Deseado estuary, where they faced a tragic end. After a month, the survivors were rescued and brought to the Islands, but the Swift would remain there for over 200 years. Theoretical Framework (chap. 4): The research on the metallurgy of the site was defined by an interdisciplinary perspective, across two scientific specialities: 1. Historical Maritime Archaeology, which is focused on the study of human past activities related to aquatic and intertidal/foreshore contexts –the maritime navigation has a highlighted place–, and for which written and other historical sources are available. These studies have contributed to known many aspects about modern society, such as military activities, commerce and exchange, exploitation of aquatic resources, and the European colonialism. The historical shipwrecks have been occupied a protagonist place in this regards –due to the great relevance that the maritime and revering environment have over centuries. 2. Archaeometallurgy, that deals with the study of past knowledge and practices associated with the production, distribution, use and discard of metals –usually by means of methods, techniques and analytical specific knowledge borrowed from other scientific fields, such as Materials Science, Chemistry and Engineering. The fine-grain information obtained by means of these analytical methods and instrumentation is usually translated into some relevant technological aspects. A socio-anthropological perspective of technology has been taken, and it has especially considered the socio-cultural and historical variables that have shaped it within a particular moment. Aims and Methodology (chap. 5): The main goal of this work was to contribute to the current knowledge of the British metallurgy during the second half of the 18th-century, especially regarding maritime craft by means of the analysis of a sloop-of-war. This was accomplished fulfilling four more specific aims: 1) typological (functional) and physico-chemical characterization of a wide sample of artifacts; 2) analysis of technical features of these objects, such as design, alloys, manufacture methods and, from the latter, their operability and specificity to the maritime environment; 3) examination of evidence related to transitional or novel technologies, repaired artifacts and recycling processes; and 4) articulation between the information about the HMS Swift artifacts and data from previous researches. The sources of information used for this study consist mainly of artifacts remains from the Swift, data from historical documentation and information from other archaeological and historical researches (on other contemporaneous shipwrecks). The macroscopic characteristics were examined, and recorded by means of photos and scaled drawings. A sample (about 22 % of the collection) for microstructural and chemical analysis was selected. The characterization was done by applying the following analytical methods and instrumentation: light microscopy (LM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDXRS), wavelength dispersive X-ray spectroscopy (WDXRS), and wavelength dispersive X-ray fluorescence (WDXRF). Results (chap. 6 to 11) These sections present the results of the characterization of artifacts belonging to the following categories (one chapter for each one): ship equipment –related to the anchoring, pumping, and steering systems–; rigging components; artillery and personal weapons; furniture; utensils related to food and kitchen; clothing and uniform accessories; and some personal belongings. The information obtained from the macroscopic, microscopic and chemical characterization –in part by means of the analytical methods and instrumentation cited above– are presented. Based on this, the characteristics of the manufacture process and material quality of the artifacts are analyzed. This information is considered for discuss the operability and specificity of the artifacts to the maritime environment. Other aspects, such as the objects conditions, their site location, and relation with other pieces, are taking into account. Also, the previous data is examined in the light of the available historical data and the studied objects from other archaeological contemporaneous shipwrecks. Concluding Remarks (chap. 12): This research has allowed obtaining novel information, and discussing some aspects related to the ship technology and the artifacts used on board. The latter show a wide range of alloys and technical skills –related largely to the different mentioned categories. Particularly, those which have a special relevance regarding the ship navigability are technically complex –in terms of knowledge, materials and personnel involved in its production–, and have a notable specificity related to the environment (e.g. a relatively good resistance to marine corrosion). The macro and microstructural registered features are consistent with those of the chronological and socio-cultural context under study, and they do not differ from those which have been analyzed in contemporaneous bigger ships. Likewise, the materials and thermo-mechanic treatments analyzed would have been coherent with the functional requirements of the artifacts. A few pieces have innovative features, some of which have been used as base for further technological developments in Great Britain.
This article presents archaeometallurgical research of three types of metal objects excavated underwater from two shipwrecks in Israel: Tantura F (mid-seventh-end of eighth centuries AD) and Akko 1 (first third of nineteenth century). Both non-destructive and destructive methods were employed. The finds were manufactured by joining processes; therefore, the studies concentrated on metallurgical processes. However, these researches were multidisciplinary, combining typological analyses of the archeological objects, as well as the historical perspective. The first case study is of an iron anchor from the Tantura F shipwreck. This anchor has a typical heterogeneous wrought iron microstructure of ferrite-pearlite-cementite and Widmanstätten plates, manufactured from several blooms made by the direct process. The blooms were joined using forge-welding by an expert blacksmith, resulting in a high-quality iron product. The blooms used in the anchor's circular cross-section shank were forge-welded from iron and steel pieces, producing a composite material with superior mechanical properties. The second case study presents a 12-pdr cannonball from the Akko 1 shipwreck. The cannonball was manufactured from high-quality wrought iron, with a homogenous microstructure of iron matrix and rather large equiaxed a-ferrite grains, produced by an indirect technique, using the hot-forgewelding process. As its production technique pre-dates that of the ship, it is suggested that this cannonball was manufactured in a different place and by a different technology from the other cannonballs found in the shipwreck. It is also possible that the 12-pdr cannonball might have been used as ballast. The third case study deals with brass cases from the Akko 1 shipwreck. The cases were made of brass containing equiaxed a-brass grains with twins, manufactured from rolled sheets that may have originated in Great Britain. The parts were joined by soldering with tin-lead alloy, and it is suggested that the cases were made in an Egyptian workshop.
The seabed site of a probable Bronze Age shipwreck off the coast of Salcombe in southwest England was explored between 1977 and 1982 and from 2004 onwards. Nearly 400 objects including copper and tin ingots, bronze artefacts/fragments and gold ornaments were found, typologically dating either to c. 1300–1150 BC or 1000–800 BC. The 280 copper and 40 tin plano-convex ingots and ingot fragments represent the largest discovery , measured by total weight as well as by quantity, of plano-convex or bun ingots in northwest Europe. The Salcombe copper ingots provided a wonderful opportunity for the technical study of copper ingots in a probable shipwreck context, as opposed to terrestrial contexts of deliberate deposition. The chemical composition of 25 plano-convex copper ingots was determined using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Two artefacts from the site were also analysed for comparison with the ingots. Following the compositional analysis, a microstructural study was carried out on ten Salcombe copper ingots selected to cover those with different sizes, shapes and variable impurity levels using metallography and scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS). All the analysed copper ingots are of unalloyed copper with low levels of impurities. Sulphide inclusions are present in all samples and bulk sulphur contents are of 0.32–0.79% in the ingots but lower in the artefacts. The Salcombe ingots were found to have a quite similar impurity pattern to the Hertford Heath (England) ingots (except for iron content). They are distinctly different from the Uluburun ingots, and, to a lesser degree, from Sardinian ingots. The results are inconclusive as to how the Salcombe ingots were made. On the one hand, the very low concentration of iron and the absence of cuprite inclusions suggest that the ingots were primary smelting products of the primitive smelting process rather than produced from re-melting or refining of primary smelting lumps. On the other hand, the dense metal with very low porosity suggests the product of refining and re-casting operations under reducing conditions. However, the small ingots are not likely to have resulted from breaking of large ingots. The chemical compositions of the Salcombe ingots point to British or Western European sources although the connection with other regions cannot be excluded for some of the ingots. Further studies including lead isotope analysis are needed to address the question of provenance of the copper ingots, which would contribute to the re-emerging debates surrounding the European Bronze Age metal trade.
Historic England Research Report Series 04-2019, 2020
Seventeen copper alloy objects and 11 tin alloy objects from the London protected wreck site, Project HE PR6901, were analysed using XRF. The compositions of the objects are compared to reference material from other sites in order to show overall trends in metal composition. The results show that the alloy was chosen depending on the type of object. The copper alloy objects, including the navigational dividers, calipers and sundial, were mainly brass of consistent composition. The pins contained the highest zinc contents whereas the ring and weight were more complex alloys containing much less zinc and higher lead contents. The two spoons with touchmarks had surviving tinned areas. The pewter objects were especially heterogeneous. Most of the cutlery and tableware was made from Guild specified, tin-rich alloys, whereas other types of object, including the button, chamber pot, and the threaded spout, contained more lead.
Nails from 2,400 years old shipwreck: A study of copper in a marine archaeological environment.
The Journal of The Minerals, Metals & Materials Society , 1999
Feature Archaeotechnology Over the last 30 years, there has been a discernible increase in the number of scholars who have focused their research on early industrial organizations, a field of study that has come to be known as Archaeotechnology. Archaeologists have conducted fieldwork geared to the study of ancient technologies in a cultural context and have drawn on the laboratory analyses developed by materials scientists as one portion of their interpretive program. Papers for this bimonthly department are solicited and reviewed by Robert M. Ehrenreich of the National Materials Advisory Board of the National Research Council.