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Historic saltpetre of British Indian origin: An isotopic and socio-economic analysis
Journal of Archaeological Science: Reports 2 (2015) 532–537
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Historic saltpetre of British Indian origin: An isotopic and socio-economic analysis Chitoshi Mizota a,⁎, Yuki Furukawa b, Toshiro Yamanaka c, Osamu Okano c, Yoshihiro Nobori d a
Research Institute for Cultural Properties, Beppu University, Kita-Ishigaki 82, Beppu 874-8501, Japan Nagasaki Prefectural Tsushima Museum of History and Folklore, Imayashiki 668-1, Izuharamachi, Tsushima, Nagasaki 817-0021, Japan Department of Earth Sciences, Graduate School of Natural Science and Technology, Okayama University, 1-1, Naka 3-chome, Tsushima, Kita-ku, Okayama 700-8530, Japan d Faculty of Agriculture, Yamagata University, Wakabamachi 1-26, Tsuruoka 997-8555, Japan b c
a r t i c l e
i n f o
Article history: Received 10 November 2014 Received in revised form 27 April 2015 Accepted 3 May 2015 Available online 11 May 2015 Keywords: Gunpowder ingredient Nitrification Saltpetre industry Stable isotopes Provenance
a b s t r a c t High-grade, historic saltpetre (KNO3) for gunpowder manufacture amounting to more than 50 kg was excavated from the store house of the Nagasaki Prefectural Tsushima Museum of History and Folklore (NPTMHF), located at western Kyushu, Japan under very well preserved conditions. It represents the largest economic specimen in the world-wide mineral collection. High precision 14C dating by accelerator mass spectrometry for associated wooded chips of the container together with the Japanese traditional wrapping paper shows raw radiocarbon ages of 1868 ± 15 and 1880 ± 20, respectively, corresponding to the maximal demand for saltpetre in the modern Japan. Distinctive δ15Nnitrate-nitrogen values (+13‰) and 87Sr/86Sr ratios (0.715) are indicative of the exotic origin, at the time when the British Indian product under the monopoly industry of the Empire of the United Kingdom prevailed. The nitrogen isotopic signature (δ15N = +17‰) is comparable with two types of authentic Bengal saltpetre specimens from the Natural History Museum (NHM) in London donated in the early 1850s. Rough saltpetre once produced in the Ganga River Valley was subject to re-crystallization process in the United Kingdom, as evidenced by shifting 87Sr/86Sr ratios from 0.722 (rough saltpetre) to 0.708 (refined saltpetre). A close examination of historical documents (1865 to 1870) directly relevant to the importation of British saltpetre into Nagasaki harbor during this time was made for both the Japanese (treasure documents kept in the custom house at Nagasaki) and the United Kingdom sites (parliamentary papers). Combination of geochemical and socio-historical evidences elucidates the maritime route of world-wide saltpetre marketing at this time. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction Saltpetre (KNO3) constitutes one of the most important ingredients of gunpowder. Economic deposits seldom occur in natural conditions, but instead production relied on industrial biotechnology which involves microbial mineralization of organic nitrogen waste followed by nitrification under suitable soil moisture and temperature regimes. In the 17th to early 20th centuries, British Indian saltpetre was a monopoly of the United Kingdom. Extensive and intensive socio-economic studies revealed their contribution to the establishment of the Empire of the United Kingdom (Buchanan, 2006; Frey, 2009; Cressy, 2011). Huge amounts of crude saltpetre produced in the Ganga River Valley located in East India, particularly in Bihar and neighboring provinces were transported from Calcutta to the United Kingdom. Depending on the demands, the annual amounts ranged from ca. 20,000 to 50,000 t (Marshall, 1917; Frey, 2009; Cressy, 2011). Crude saltpetre was then refined in several refineries in the United Kingdom, and converted into ⁎ Corresponding author. Tel./fax: +81 942 26 4007. E-mail address: [email protected] (C. Mizota).
http://dx.doi.org/10.1016/j.jasrep.2015.05.004 2352-409X/© 2015 Elsevier Ltd. All rights reserved.
gunpowder by mixing with ingredients: native sulphur imported from Sicily (Italy) and domestic charcoal carbon (Gray et al., 1982). British gunpowder served as a driving force during the Napoleonic (1810) and Civil Wars (1851 to 1854) (Gray et al., 1982; Frey, 2009; Cressy, 2011). However, in spite of its historical importance, the archaeological and geochemical characterization of British saltpetre is largely unknown. Due to its expendable nature and high solubility in water, historic saltpetre is difficult to preserve in an intact state under humid climates such as the Japanese islands. Historical institutions with national organization under careful and persistent management facilitate long-term conservation. Such opportunities can be found by reconnaissance survey of the collections of cultural properties belonging to ancient families inherited from the early 19th century. In previous studies, we have analyzed several historic gunpowder specimens from the middle 19th century in Japan, finding unique ingredient saltpetre-nitrates characterized by high δ15N values up to +13‰ (Mizota and Yamanaka, 2014; Mizota et al., 2014). The secondary isotopic exchange of N–O bond once formed in nitrate with ambient solutions is known to be limited during the post-formational conditions (Kaneko and Poulson, 2013). Based on the comparative analysis with domestic
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saltpetre and in combination with relevant documents, exotic saltpetre of British Indian provenance was interpreted to widely prevail in the world market during the time (Mizota and Yamanaka, 2014; Mizota et al., 2014). Nevertheless, validity of the interpretation awaits further analysis of the authentic saltpetre produced at the times. If British Indian origin is assumed, rationale for the geography is required. As a traditional geochemical tracer, strontium isotope ratios (87Sr/86Sr) have been used in many studies to define geographical sources (Capo et al., 1998; Nisi et al., 2008). 87Sr/86Sr ratios reflect the distinctive bedrock types within a drainage area (Notsu et al., 1991). The use of 87Sr/86Sr ratios has recently been extended into food, forensic, and environmental sciences (Voerkelius et al., 2010). Very high 87Sr/86Sr ratios in river/ground waters and suspended solids from the Ganga River Valley are documented (Krishnaswani et al., 1992; Singh et al., 2010). Such distinctive values would also reflect saltpetre produced in British India during the time. The objective of the present study is to characterize economic saltpetre specimens prevailing during the middle 19th century in south-western Japan and the United Kingdom using isotopic technologies (δ15Nsaltpetre-nitrogen and 87Sr/86Sr ratios). Historical documents (1865 to 1870) kept in a custom house at Nagasaki harbor, and British parliamentary papers were also examined for the record of saltpetre importation.
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a)
b)
2. Materials and methods 2.1. Description of the specimens examined Economic saltpetre samples analyzed in the present study were donated by the NPTMHF (Tsushima, Nagasaki, south-western Japan) and the NHM (London, The United Kingdom). The NPTMHF (34°12′ 15.95″ N, 129°17′ 12.83″ E; elevation of 27 m) was settled on Tsushima Island, lying between North Kyushu and South Korea. The institution involves diverse cultural properties inherited from the Soh family, who were long-term lords of the domain of Tsushima (from early 17th to middle 19th century). Fig. 1a shows two, dual lined wooden boxes in which whitish salty masses are fully packed. Each box is 27.5 × 57.5 cm long, and 23.5 cm high. There can be seen a clear boundary between heartwood (dark-brown colored part) and sapwood (whitish-yellow part) of the inside cover of the boxes. The ratio of late wood and faded color of early and late wood provides one of the identification criteria for the tree species used. Such unique fabric shows that the plates consist of slates of flat grained Japanese cedar (Cryptomeria japonica). Coast redwoods (Sequoia sempervirens) are unlikely, since occurrence is limited to the coastal ranges of western USA. It is thus concluded that the woody materials derived from common tree species in Japan. The entire weight including the wooden two boxes amounts 56 kg. There were no observable characters on the surface or interior of the boxes to indicate the contents. Based on the visual appearance and knowledge of common human uses, it was considered the whitish salty masses consisted of potassium alum (AlK(SO4)2·12H2O) or saltpetre. Saltpetre as a major component is highly plausible, since the crystals are non-deliquescent and non-hygroscopic in nature. The physical appearance is comparable to ‘wet snow heap’ (refined saltpetre) piled up in the saltpetre refinery in Waltham Abbey (Essex, The United Kingdom) (Fig. 2 in FitzGerald, 1895). Clear pseudo-hexagonal prism has developed along the long axis up to 25 cm, indicating progressive crystallization from the concentrated mother solution with ample spaces. Another sample examined in the present study was authentic saltpetres of known British Indian origin (so-called Bengal niter). Historic specimens were stored in the NHM located in London, United Kingdom. Two distinctive types of Bengal saltpetre are discernible. It has been documented that saltpetre produced in British India (Leather and Mukerji, 1911; Hutchnson, 1917; Marshall, 1917) is not enough pure for gunpowder manufacture. Therefore, re-crystallization by selective elimination of impurity other than KNO3 was made in the refinery
Fig. 1. (a): Whitish salt masses packed in the dual lined wooden boxes. Dark brown colored parts of the surface of the inner cover represent heartwood, whereas grayish yellow colored sapwood. There can be seen clear tree rings on the cover plates. The box covers are designed to have special devices which are not allowed to remove from the boxes. The boxes are kept in the stock house of the NPTMHF (Tsushima, Nagasaki, western Kyushu), (b): refined (upper box) and rough (lower box) Bengal saltpetre specimens. The specimens are kept in the stock floor of the NHM at London, The United Kingdom. Two contrasting crystal habits of the Bengal saltpetre specimens kept in the museum. Very well developed termination of the pseudo-hexagonal prism (refer upper box) is evident. A paper box (refer right side of lower box) contains grayish-white colored rough saltpetre which involves the explanation label for the identity.
within the royal gunpowder mills in the United Kingdom (Goodenough, 1868; FitzGerald, 1895; Gray et al., 1982). The saltpetre specimens kept in NHM represent the historic processes prevailed at the time. Longprisms of up to 30 cm long and c. 4 cm diameter of pseudo-hexagonal habit (upper box in Fig. 1b, NHM specimen number; BM1985, MI from 21838 throughout 21842 and 23249) represent well refined specimens, whereas light-gray minute crystals in a small paper box (‘Rough saltpetre’, lower box in Fig. 1b, NHM specimen number; BM1985, MI 21863) can be observable. The latter specimen has an associated explanation label which indicates Bengal niter written by “Presented by Mefsrs Richardson Bros. and Co.”. Use of the old English “Mefsrs” (corresponding to current Messrs.) prevailed during the middle 19th century. A literature survey suggests that these specimens were exhibited on the
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occasion of The Great Exhibition 1851 held at Hyde Park at London (Hon-No Tomosha, Tokyo, Japan, Tomosha, 1996). The documents imply the preparation date of the rough saltpetre as older than 1851. The present-day Natural History Museum (London) was constructed on the neighboring location after completion after the exhibition. For the well refined saltpetre specimens with the elongated prism and semi-pyramidal termination (Fig. 1b), there exists no detailed documents in the museum. The associated identity label (refer mid-position) indicates “crystals (pseudo-hexagonal of refined niter or saltpetre) (potassium nitrate (KNO3))”. Close acquisition number (21840) associated with that of the specimen in a paper box (21863) implies the same commodity donated by Richardson Bros. and Co. at the occasion of the exhibition. The crystal habit of the long prism indicates gradual growth from the ambient solution containing concentrated KNO3 through a differential crystallization technique with ample space. According to the author's database survey, the Bengal niter specimens represent the largest in the world-wide mineral collection. 2.2. Analytical methods 14 C ages for wooden chips of the box cover and detached band consisting of Japanese traditional paper were determined using a high precision accelerator mass spectrometry at Yamagata University (Yamagata, northeastern Japan). Prior to conversion into carbon dioxide and then graphite, sample materials were treated with 1 M HCl following 1 M NaOH digestion to exclude labile carbonaceous contaminants. The 14C dates were calibrated, according to the procedure by Reimer et al. (2009). Salt masses amounting 5 to 10 mg were dissolved in distilled water. The resulting solution was passed through a Millipore filter with a pore size of 0.45 μm. The filtrate was subject to quantitative determination and stable isotopic analysis (δ15N) for nitrate-nitrogen (NO− 3 ) using gas-tight container (Mizota and Yamanaka, 2014). Nitrate was quantitatively reduced into ammonia by use of Devarda's alloy (yields: nearly 100%) and nitrate-nitrogen was measured by volumetric titration using methyl red and bromocresol-green mixture as a color indicator. The analytical accuracy for the overall procedure using our protocol is ±2%.
a)
For determination of δ15N values of nitrate in the extract, nitrate was first transformed into ammonia as described above, and finally transformed into ammonium sulfate under slight excess presence of sulphuric acid on a GF/F glass filter. 15N/14N ratios for the samples were measured by a continuous-flow mass spectrometer (GV Instruments, Manchester, UK) coupled with an elemental analyzer. All isotopic values were shown as common δ15N notation, per mil deviation relative to international standard; atmospheric nitrogen. The analytical error during the overall process of mass spectrometry is less than ±0.2‰. K in the filtrate was determined by atomic absorption spectrophotometry (AAanalyst 100, PerkinElmer, Massachusetts, USA). Error in the quantitative analysis for K was estimated at ±5%. Quantitative determination of Rb and Sr was made on samples of 130 to 150 mg aliquots. The samples were dissolved in 1 M HCl solution followed by evaporative concentration and re-dissolution. The resulting solution was applied using Muromac column chromatography packed with the AG500W 12X 200–400 resin (Bio-Rd lab.). Sr-containing elute was again evaporated. All the fractions were smeared on a single tungsten filament. 87Sr/86Sr was determined with a Varian MAT262 mass spectrometer. An international Sr standard (NIST SRM987) gave 87 Sr/86Sr ratios of 0.71022 to 0.71023 during the measurement. Historical documents kept in the custom house at Nagasaki harbor, Japan (present-day Nagasaki Museum of History and Culture; Document Numbers: B14-33-1-1, B14-33-1-2, B14-34-7-1, B14-34-7-2, B-14-171-31 and B14-171-3-2 written in old Japanese) and British parliamentary papers (Irish University Press, 1971) were examined for records of saltpetre importation from 1859 to 1870. The former documents are daily records (Fig. 2), where the latter are annual records, respectively. Old Japanese systems for weight presentation were converted into current tonnages. 3. Results and discussion 3.1. 14C age determination (Table 1) Age control is a prerequisite for studies on the historic cultural properties. High precision accelerator mass spectrometry (AMS) has
b)
Fig. 2. (a): A photo showing the cover page of the file of custom documents (Document number: B14-171-3-1) kept at the Nagasaki Museum of History and Culture at Nagasaki. The surface letters written by free-hand Japanese (in vertical direction) indicate the document start from the first January to the end of June, 1867. (b): First example of the application form for the purchase of saltpetre compiled in the file. The free-hand written Japanese letters (in the vertical direction) located on the mid-line indicate that the Kumamoto domain is applying 30 t of saltpetre through a German merchant, Kniffler Co. on the 5th of January, 1867. The corresponding receipt is not attached on the following pages.
C. Mizota et al. / Journal of Archaeological Science: Reports 2 (2015) 532–537 Table 1 Analytical data for 14C dating. Laboratory
Uncalibrated age
Calibrated
Sample
Number
(yr BP ± 1σ)
Date range (2σ)
Wood chips Papers
YU-1857 YU-1630
145 ± 15 135 ± 20
1723 AD–1779 AD 1799 AD–1892 AD
increasingly been used for 14C age determination among the interdisciplinary sciences. The AMS method is applicable for small amounts of carbonaceous materials (0.2 to 2 mg as elemental carbon) aged less than ca. 50,000 to 60,000 years. Whitish salt masses packed in the wooden boxes from the NPTMHF did not contain enough carbon for direct age determination by AMS. Instead, the method was applied to two other samples. Sapwood chips from the outermost part of the liner wall and the detached Japanese traditional paper band yielded the raw radiocarbon ages of 1868 ± 15 (code no. YU-1857) and 1880 ± 20 (code no. YU-1630), respectively. The former age just corresponds to a transitional date from the period of government in Japan by the Tokugawa Shogunate to Meiji Restoration when the abrupt changes in the political regimes occurred. From the data, the age of box production is estimated at close to maximal of the demand for materials in Japan, as described in the Introduction section. The Japanese cover paper attached on the surface of the boxes was aged slightly younger than wooden chips. The paper was probably attached several years after packing of the whitish salty masses. The obtained raw radiocarbon ages are around 1880. The calibrated age ranged is rather extensive (1720 AD to 1890 AD), because this date falls in the middle of a period of extensive carbon pollution caused by the fossil fuel emissions of the Industrial Revolution. As such, raw radiocarbon ages in the 1880s, although indicative, cannot be considered to be very definitive. 3.2. Chemical and nitrogen isotope composition (δ15N) Table 2 shows the chemical and nitrogen isotopic composition of whitish salty masses from the NPTMHF and Bengal niter from the NHM at London. To test the homogeneity, four repeated analysis was made for samples packed in each of boxes A and B. The concentrations of K (38.4%) and nitrate-nitrogen (12.4 and 12.5%) for both boxes were nearly identical, indicating very high homogeneity of content. Since pure KNO3 consists of 38.7% K and 13.9% nitrate-nitrogen, the salty masses demonstrated to be nearly pure saltpetre. Assuming that all the nitrate-nitrogen in the samples are allocated to KNO3, the purity is around 90%. The two authentic saltpetre specimens to be of Bengal origin showed a somewhat lower K content (34.6 and 37.0%) than those from NPTMHF, but slightly higher nitrate-nitrogen in the range of 13.1 and 13.2%. The estimated content of saltpetre in the rough niter specimen (21863) is clearly higher than those reported from four locations in British India (27 to 68%; Leather and Mukerji, 1911). Whitish masses from the boxes A and B gave an identical δ15N value of +13.2‰, whereas those from the Bengal saltpetre specimens (+16.5 and 16.6‰) gave c. 3‰ higher than those from the former specimens.
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Difference between the refined and rough saltpetre samples may be the result of derivation from different lots. Depending on the environmental conditions, the nitrogen isotopic fractionation associated with the microbiological nitrification shows a range of variation from 35 to 60‰ (Robinson, 2001). Such high δ15N values of the specimens substantiate the unique process of the Bengal saltpetre formation, being clearly distinctive from those of local saltpetre prevailing during the middle 19th century in central Japan (Gokayama, Toyama, δ15N values = + 4.7 to + 6.0‰ with an average of + 5.5‰; Mizota and Yamanaka, 2014). Microbial nitrates formed from the residual ammonium (resulting in enrichment by 15N) remaining after the emission of 14 N-enriched NH3 under open air as in British India are a plausible mechanism. Spatial distribution patterns of total inorganic nitrogen deposition in 1860 (Galloway et al., 2004), ammonia and nitrous oxide in free atmosphere (2000; Yamaji et al., 2004), and global ammonia distribution (2008: Clarisse et al., 2009), are all indicative of intensified nitrogen cycles along the Ganga River Valley. As already described in the proceeding section of the Introduction, Bengal saltpetre was a monopoly industry of early modern England. Details on the accounts have been given in several technical papers published in colonial India (Leather and Mukerji, 1911; Hutchnson, 1917). The outline of the production process is briefly summarized below. The ultimate source of nitrogen for saltpetre production is human and animal (mainly buffalo) excreta deposited in the form of the organic nitrogen. Excretion on the ground is customary along the region of the Ganga River plain where the human density is quite high. The organic waste deposited on the ground surface is subject to mineralization, following nitrification under alternating wet and dry weather conditions. The resulting surface soils were enriched by KNO3 which were taken by local saltpetre-men. Rough saltpetre was yielded by water extraction, followed by differential crystallization to remove impurities other than KNO3. The processes involving the nitrification are highly sensitive to environmental factors, particularly soil conditions (soil moisture and temperature regimes) (Aulakh et al., 1992; Mizota et al., 2006), resulting in wider ranges in isotopic fractionation factors, as compiled by Robinson (2001). Thus, literature review of historical documents relevant to the biotechnology supports the observed nitrogen isotopic variation for the NPTMHF and the NHM at London. 3.3. 87Sr/86Sr ratios Saltpetre manufacture involves the dissolution and re-crystallization from the concentrated KNO3 solution where meteoric ground/or river waters are used. The resulting saltpetre commodity contains strontium as a minor constituent. Table 3 summarizes the content of rubidium and strontium together with strontium isotope composition. The content of rubidium in the selected saltpetre samples (22.2 to 44.8 ppm; samples from the NPTMHF and acquisition number 21863 from the NHM at London) is two orders of magnitude higher than that of the associated strontium (0.17 and 0.74 ppm). Saltpetre specimens (salt in the Boxes in A and B and Bengal saltpetre: specimen number of 21863) gave 87 Sr/86Sr ratios in range from 0.714923 to 0.722575, exhibiting a trend of higher values in rough samples than those of refined specimens. These strontium isotopic values are nearly consistent with those reported
Table 2 Averaged chemical and nitrogen isotopic compositions of samples. Host institution
Nagasaki Prefectural Tsushima Museum of History and Folklore Natural History Museum (London) a b c
Refer Fig. 1a. A: right box, B: left box. Refined niter of detached single crystals (refer Fig. 1b; upper box). Rough saltpetre (refer Fig. 1b; minute crystals in the lower box).
Group or code No.
Whitish mass in Box Aa Whitish mass in Box Ba Bengal niter 21840b Bengal niter 21863c
Numbers of analysis
4 4 2 3
Content (w.%) K
NO− 3 -nitrogen
δ15Nnitrate (‰)
38.4 38.4 34.6 37.0
12.5 12.4 13.1 13.2
+13.2 +13.2 +16.5 +16.6
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4. Conclusion
Table 3 Concentration of Rb and Sr,and 87Sr/86Sr ratios for samples. Samples
NPTMHF NHM in London
No.
Box A Box B 21840a 21863a
Numbers of analysis
1 1 1 1
Content (ppm)
87
Sr/86Sr
Rb
Sr
Ratios
Error
nd 22.2 33.3 44.8
nd 0.17 2.64 0.74
0.715325 0.714923 0.708133 0.722575
0.000014 0.000011 0.000012 0.000010
nd = not determined. a Refer footnote in Table 2.
from the dissolved strontium in Ganga river waters collected near Patna (0.7168 to 0.7400; Krishnaswani et al., 1992) where the intensive saltpetre industry existed, but distinct from those of the wide-spread spring and mineral waters throughout the Japanese Islands (0.703 to 0.712; Notsu et al., 1991), probably young age of bedrocks. One refined Bengal saltpetre specimen (specimen number: 21840) showed a different trend from those other specimens, giving 87Sr/86Sr ratio of 0.708133. Such a low value probably indicates secondary incorporation and exchange with local strontium during the processes of dissolution and subsequent re-crystallization. Strontium isotope composition of mineral water throughout the United Kingdom is documented (Montgomery et al., 2006). The strontium isotope ratios of the mineral water available to the major saltpetre refineries (Faversham (Kent), Waltham Abbey (Essex), and Chilworth (Surrey) in England: Cressy, 2011) are nearly 0.7077, reflecting the young bedrock ages.
3.4. Examination for the historical documents kept at custom house in Nagasaki and British parliamentary papers during 1859 to 1870 Once we had established the identity of the whitish salty masses kept in the NPTMHF as the economic saltpetre with British Indian provenance prevailed during the middle 19th century, the historical documents provided additional evidence for the marketing route. Tsushima Island is near Nagasaki harbor (32°44′ N, 129°52′ E) which was a major trading port. Table 4 summarizes the annual importation of saltpetre at the Nagasaki harbor which had the facility to trade with foreign countries. Close examination for the harbors like Kanagawa (presentday Yokohama) and Hakodate (southern Hokkaido) shows that they do not have any records of the importation during the appropriate time (Irish University Press, 1971). There can be seen a clear trend on the temporal changes in the data. The British parliamentary papers always gave higher figures, relative to the corresponding year for the custom house at Nagasaki. Such a discrepancy could not be understood at the moment. Probably, custom at Nagasaki did not function well at the time. Amounts of the imported saltpetre abruptly increase from 1867 (168 t; custom house at Nagasaki) or 1866 (351 t; British parliamentary papers), until 1870 with a maximum in 1867. The maximum corresponds to just one year before the initiation of the Boshin War (civil war) when the domestic demand for saltpetre attending its maximal in Japan. The chronological trends well explain the 14C ages for the production date of wooden box, as described above.
Table 4 Temporal changes in the annual amounts of imported saltpetre at Nagasaki harbor. Estimates on the imported saltpetre (tons/year) Calendar year
Custom house at Nagasaki
British parliamentary papers
1865 1866 1867 1868 1869 1870
None None 168 40 36 None
None 351 436 200 150 None
A large-sized, section of economic saltpetre for gunpowder ingredients was excavated from the store house of the NPTMHF. Chemical and isotopic analyses as comparing this with those from the two types (rough and refined) of authentic Bengal saltpetre (NHM) revealed it as from British India during the middle 19th century. The rough saltpetre matches the expectation that it comes from British India, while the refined saltpetre should have faced some post-collecting alteration in the dissolving and refinement processes within the United Kingdom. Historical documents recorded at the custom house in Nagasaki harbor and British parliamentary papers support the validity of the interpretation based on the geochemical evidence. The most probable route of the transportation is that historic saltpetre first produced in British India along the Ganga River Valley and transported to be refined in the United Kingdom, then exported to Nagasaki. Acknowledgments Bengal saltpetre specimens were kindly donated by mineral curator, Dr. Peter Tandy, of the Natural History Museum at London. English on the early version of the manuscript was improved by Dr. A. L. Cronin (Iwate University). We are grateful to them. References Aulakh, M.S., Doran, J.W., Mosier, A.R., 1992. Soil denitrification: significance, measurement, and effects on management. Adv. Soil Sci. 18, 1–57. Buchanan, B.J., 2006. Saltpetre: a commodity of empire. In: Buchanan, B.J. (Ed.), Gunpowder, Explosives and the State: a Technological History. Ashgate Publishing Limited, England, pp. 67–90. Capo, R.C., Stewart, B.W., Chadwick, O.A., 1998. Strontium isotopes as tracers of ecosystem processes: theory and methods. Geoderma 82, 197–225. Clarisse, L., Clerbaux, C., Dentener, F., Hurtmans, D., Coheur, P.-F., 2009. Global ammonia distribution derived from infrared satellite observations. Nat. Geosci. 2, 479–483. Cressy, D., 2011. Saltpetre, state security and vexation in early modern England. Past Present 212, 73–111. FitzGerald, W.G., 1895. How explosives are made. Strand Mag. 9, 307–318. Frey, J.W., 2009. The Indian saltpeter trade, the military revolution, and the rise of Britain as a global superpower. Historian 71, 507–554. Galloway, J.N., et al., 2004. Nitrogen cycles: past, present, and future. Biogeochemistry 70, 153–226. Goodenough, R.A., 1868. Notes on Gunpowder. The Royal Artillery Institution, Woolwich and London, United Kingdom, pp. 1–52. Gray, E., Marsh, H., McLaren, M., 1982. Review. A short history of gunpowder and the role of charcoal in its manufacture. J. Mater. Sci. 17, 3385–3400. Hutchnson, C.M., 1917. Saltpetre: its origin and extraction in India. Bull. Agric. Res. Inst. Pusa 68, 1–24. Irish University Press, 1971. Irish University Press Area Studies Series, British Parliamentary Papers, Japan 4. Embassy and Consular Commercial Reports, 1859–1871pp. 1–590. Kaneko, M., Poulson, S.R., 2013. The rate of oxygen isotope exchange between nitrate and water. Geochim. Cosmochim. Acta 118, 148–156. Krishnaswani, S., Trivedi, J.R., Sarin, M.M., Ramesh, R., Sharma, K.K., 1992. Strontium isotopes and rubidium in the Ganga-Brahmaputra river system: weathering in the Himalaya, fluxes to the Bay of Bengal and contributions to the evolution of oceanic 87 Sr/86Sr. Earth Planet. Sci. Lett. 109, 243–253. Leather, J.W., Mukerji, J.N., 1911. The Indian saltpetre industry. Bull. Agric. Res. Inst. Pusa 24, 1–19. Marshall, A., 1917. Explosives. Second Edition History and Manufacture vol. 1. J. & A. Churchhill, London, pp. 1–407. Mizota, C., Yamanaka, T., 2014. Stable isotopic characterization of gunpowder ingredients from the mid to late nineteenth century in Japan. J. Archaeol. Sci. 45, 90–95. Mizota, C., Yamaguchi, Y., Noborio, K., 2006. Microbial transformation of nitrogen in cattle slurry as applied to an Andisol grassland. J. Jpn. Soc. Soil Phys. 104, 13–26. Mizota, C., Yamanaka, T., Ichinose, A., 2014. Provenance of historic gunpowder from south-western Japan: a stable isotopic approach. Archaeometry http://dx.doi.org/ 10.1111/arcm. 2141 (Available online). Montgomery, J., Evans, J.A., Wildman, G., 2006. 87Sr/86Sr isotope composition of bottled British mineral waters for environmental and forensic purposes. Appl. Geochem. 21, 1626–1634. Nisi, G.B., Buccianti, A., Vaselli, O., Perini, G., Tssi, F., Minissale, A., Montegrossi, G., 2008. Hydrogeochemistry and strontium isotopes in the Arono River Basin (Tuscany, Italy): constraints on natural controls by statistical modeling. J. Hydrol. 360, 166–183. Notsu, K., Wakita, H., Nakamura, Y., 1991. Strontium isotopic composition of hot spring and mineral waters. Jpn. Appl. Geochem. 6, 543–551. Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., Burr, G.S., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., Hajdas, I., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kaiser, K.F., Kromer, B., McCormac,
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Journal of Archaeological Science: Reports journal homepage: http://ees.elsevier.com/jasrep
Historic saltpetre of British Indian origin: An isotopic and socio-economic analysis Chitoshi Mizota a,⁎, Yuki Furukawa b, Toshiro Yamanaka c, Osamu Okano c, Yoshihiro Nobori d a
Research Institute for Cultural Properties, Beppu University, Kita-Ishigaki 82, Beppu 874-8501, Japan Nagasaki Prefectural Tsushima Museum of History and Folklore, Imayashiki 668-1, Izuharamachi, Tsushima, Nagasaki 817-0021, Japan Department of Earth Sciences, Graduate School of Natural Science and Technology, Okayama University, 1-1, Naka 3-chome, Tsushima, Kita-ku, Okayama 700-8530, Japan d Faculty of Agriculture, Yamagata University, Wakabamachi 1-26, Tsuruoka 997-8555, Japan b c
a r t i c l e
i n f o
Article history: Received 10 November 2014 Received in revised form 27 April 2015 Accepted 3 May 2015 Available online 11 May 2015 Keywords: Gunpowder ingredient Nitrification Saltpetre industry Stable isotopes Provenance
a b s t r a c t High-grade, historic saltpetre (KNO3) for gunpowder manufacture amounting to more than 50 kg was excavated from the store house of the Nagasaki Prefectural Tsushima Museum of History and Folklore (NPTMHF), located at western Kyushu, Japan under very well preserved conditions. It represents the largest economic specimen in the world-wide mineral collection. High precision 14C dating by accelerator mass spectrometry for associated wooded chips of the container together with the Japanese traditional wrapping paper shows raw radiocarbon ages of 1868 ± 15 and 1880 ± 20, respectively, corresponding to the maximal demand for saltpetre in the modern Japan. Distinctive δ15Nnitrate-nitrogen values (+13‰) and 87Sr/86Sr ratios (0.715) are indicative of the exotic origin, at the time when the British Indian product under the monopoly industry of the Empire of the United Kingdom prevailed. The nitrogen isotopic signature (δ15N = +17‰) is comparable with two types of authentic Bengal saltpetre specimens from the Natural History Museum (NHM) in London donated in the early 1850s. Rough saltpetre once produced in the Ganga River Valley was subject to re-crystallization process in the United Kingdom, as evidenced by shifting 87Sr/86Sr ratios from 0.722 (rough saltpetre) to 0.708 (refined saltpetre). A close examination of historical documents (1865 to 1870) directly relevant to the importation of British saltpetre into Nagasaki harbor during this time was made for both the Japanese (treasure documents kept in the custom house at Nagasaki) and the United Kingdom sites (parliamentary papers). Combination of geochemical and socio-historical evidences elucidates the maritime route of world-wide saltpetre marketing at this time. © 2015 Elsevier Ltd. All rights reserved.
1. Introduction Saltpetre (KNO3) constitutes one of the most important ingredients of gunpowder. Economic deposits seldom occur in natural conditions, but instead production relied on industrial biotechnology which involves microbial mineralization of organic nitrogen waste followed by nitrification under suitable soil moisture and temperature regimes. In the 17th to early 20th centuries, British Indian saltpetre was a monopoly of the United Kingdom. Extensive and intensive socio-economic studies revealed their contribution to the establishment of the Empire of the United Kingdom (Buchanan, 2006; Frey, 2009; Cressy, 2011). Huge amounts of crude saltpetre produced in the Ganga River Valley located in East India, particularly in Bihar and neighboring provinces were transported from Calcutta to the United Kingdom. Depending on the demands, the annual amounts ranged from ca. 20,000 to 50,000 t (Marshall, 1917; Frey, 2009; Cressy, 2011). Crude saltpetre was then refined in several refineries in the United Kingdom, and converted into ⁎ Corresponding author. Tel./fax: +81 942 26 4007. E-mail address: [email protected] (C. Mizota).
http://dx.doi.org/10.1016/j.jasrep.2015.05.004 2352-409X/© 2015 Elsevier Ltd. All rights reserved.
gunpowder by mixing with ingredients: native sulphur imported from Sicily (Italy) and domestic charcoal carbon (Gray et al., 1982). British gunpowder served as a driving force during the Napoleonic (1810) and Civil Wars (1851 to 1854) (Gray et al., 1982; Frey, 2009; Cressy, 2011). However, in spite of its historical importance, the archaeological and geochemical characterization of British saltpetre is largely unknown. Due to its expendable nature and high solubility in water, historic saltpetre is difficult to preserve in an intact state under humid climates such as the Japanese islands. Historical institutions with national organization under careful and persistent management facilitate long-term conservation. Such opportunities can be found by reconnaissance survey of the collections of cultural properties belonging to ancient families inherited from the early 19th century. In previous studies, we have analyzed several historic gunpowder specimens from the middle 19th century in Japan, finding unique ingredient saltpetre-nitrates characterized by high δ15N values up to +13‰ (Mizota and Yamanaka, 2014; Mizota et al., 2014). The secondary isotopic exchange of N–O bond once formed in nitrate with ambient solutions is known to be limited during the post-formational conditions (Kaneko and Poulson, 2013). Based on the comparative analysis with domestic
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saltpetre and in combination with relevant documents, exotic saltpetre of British Indian provenance was interpreted to widely prevail in the world market during the time (Mizota and Yamanaka, 2014; Mizota et al., 2014). Nevertheless, validity of the interpretation awaits further analysis of the authentic saltpetre produced at the times. If British Indian origin is assumed, rationale for the geography is required. As a traditional geochemical tracer, strontium isotope ratios (87Sr/86Sr) have been used in many studies to define geographical sources (Capo et al., 1998; Nisi et al., 2008). 87Sr/86Sr ratios reflect the distinctive bedrock types within a drainage area (Notsu et al., 1991). The use of 87Sr/86Sr ratios has recently been extended into food, forensic, and environmental sciences (Voerkelius et al., 2010). Very high 87Sr/86Sr ratios in river/ground waters and suspended solids from the Ganga River Valley are documented (Krishnaswani et al., 1992; Singh et al., 2010). Such distinctive values would also reflect saltpetre produced in British India during the time. The objective of the present study is to characterize economic saltpetre specimens prevailing during the middle 19th century in south-western Japan and the United Kingdom using isotopic technologies (δ15Nsaltpetre-nitrogen and 87Sr/86Sr ratios). Historical documents (1865 to 1870) kept in a custom house at Nagasaki harbor, and British parliamentary papers were also examined for the record of saltpetre importation.
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a)
b)
2. Materials and methods 2.1. Description of the specimens examined Economic saltpetre samples analyzed in the present study were donated by the NPTMHF (Tsushima, Nagasaki, south-western Japan) and the NHM (London, The United Kingdom). The NPTMHF (34°12′ 15.95″ N, 129°17′ 12.83″ E; elevation of 27 m) was settled on Tsushima Island, lying between North Kyushu and South Korea. The institution involves diverse cultural properties inherited from the Soh family, who were long-term lords of the domain of Tsushima (from early 17th to middle 19th century). Fig. 1a shows two, dual lined wooden boxes in which whitish salty masses are fully packed. Each box is 27.5 × 57.5 cm long, and 23.5 cm high. There can be seen a clear boundary between heartwood (dark-brown colored part) and sapwood (whitish-yellow part) of the inside cover of the boxes. The ratio of late wood and faded color of early and late wood provides one of the identification criteria for the tree species used. Such unique fabric shows that the plates consist of slates of flat grained Japanese cedar (Cryptomeria japonica). Coast redwoods (Sequoia sempervirens) are unlikely, since occurrence is limited to the coastal ranges of western USA. It is thus concluded that the woody materials derived from common tree species in Japan. The entire weight including the wooden two boxes amounts 56 kg. There were no observable characters on the surface or interior of the boxes to indicate the contents. Based on the visual appearance and knowledge of common human uses, it was considered the whitish salty masses consisted of potassium alum (AlK(SO4)2·12H2O) or saltpetre. Saltpetre as a major component is highly plausible, since the crystals are non-deliquescent and non-hygroscopic in nature. The physical appearance is comparable to ‘wet snow heap’ (refined saltpetre) piled up in the saltpetre refinery in Waltham Abbey (Essex, The United Kingdom) (Fig. 2 in FitzGerald, 1895). Clear pseudo-hexagonal prism has developed along the long axis up to 25 cm, indicating progressive crystallization from the concentrated mother solution with ample spaces. Another sample examined in the present study was authentic saltpetres of known British Indian origin (so-called Bengal niter). Historic specimens were stored in the NHM located in London, United Kingdom. Two distinctive types of Bengal saltpetre are discernible. It has been documented that saltpetre produced in British India (Leather and Mukerji, 1911; Hutchnson, 1917; Marshall, 1917) is not enough pure for gunpowder manufacture. Therefore, re-crystallization by selective elimination of impurity other than KNO3 was made in the refinery
Fig. 1. (a): Whitish salt masses packed in the dual lined wooden boxes. Dark brown colored parts of the surface of the inner cover represent heartwood, whereas grayish yellow colored sapwood. There can be seen clear tree rings on the cover plates. The box covers are designed to have special devices which are not allowed to remove from the boxes. The boxes are kept in the stock house of the NPTMHF (Tsushima, Nagasaki, western Kyushu), (b): refined (upper box) and rough (lower box) Bengal saltpetre specimens. The specimens are kept in the stock floor of the NHM at London, The United Kingdom. Two contrasting crystal habits of the Bengal saltpetre specimens kept in the museum. Very well developed termination of the pseudo-hexagonal prism (refer upper box) is evident. A paper box (refer right side of lower box) contains grayish-white colored rough saltpetre which involves the explanation label for the identity.
within the royal gunpowder mills in the United Kingdom (Goodenough, 1868; FitzGerald, 1895; Gray et al., 1982). The saltpetre specimens kept in NHM represent the historic processes prevailed at the time. Longprisms of up to 30 cm long and c. 4 cm diameter of pseudo-hexagonal habit (upper box in Fig. 1b, NHM specimen number; BM1985, MI from 21838 throughout 21842 and 23249) represent well refined specimens, whereas light-gray minute crystals in a small paper box (‘Rough saltpetre’, lower box in Fig. 1b, NHM specimen number; BM1985, MI 21863) can be observable. The latter specimen has an associated explanation label which indicates Bengal niter written by “Presented by Mefsrs Richardson Bros. and Co.”. Use of the old English “Mefsrs” (corresponding to current Messrs.) prevailed during the middle 19th century. A literature survey suggests that these specimens were exhibited on the
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occasion of The Great Exhibition 1851 held at Hyde Park at London (Hon-No Tomosha, Tokyo, Japan, Tomosha, 1996). The documents imply the preparation date of the rough saltpetre as older than 1851. The present-day Natural History Museum (London) was constructed on the neighboring location after completion after the exhibition. For the well refined saltpetre specimens with the elongated prism and semi-pyramidal termination (Fig. 1b), there exists no detailed documents in the museum. The associated identity label (refer mid-position) indicates “crystals (pseudo-hexagonal of refined niter or saltpetre) (potassium nitrate (KNO3))”. Close acquisition number (21840) associated with that of the specimen in a paper box (21863) implies the same commodity donated by Richardson Bros. and Co. at the occasion of the exhibition. The crystal habit of the long prism indicates gradual growth from the ambient solution containing concentrated KNO3 through a differential crystallization technique with ample space. According to the author's database survey, the Bengal niter specimens represent the largest in the world-wide mineral collection. 2.2. Analytical methods 14 C ages for wooden chips of the box cover and detached band consisting of Japanese traditional paper were determined using a high precision accelerator mass spectrometry at Yamagata University (Yamagata, northeastern Japan). Prior to conversion into carbon dioxide and then graphite, sample materials were treated with 1 M HCl following 1 M NaOH digestion to exclude labile carbonaceous contaminants. The 14C dates were calibrated, according to the procedure by Reimer et al. (2009). Salt masses amounting 5 to 10 mg were dissolved in distilled water. The resulting solution was passed through a Millipore filter with a pore size of 0.45 μm. The filtrate was subject to quantitative determination and stable isotopic analysis (δ15N) for nitrate-nitrogen (NO− 3 ) using gas-tight container (Mizota and Yamanaka, 2014). Nitrate was quantitatively reduced into ammonia by use of Devarda's alloy (yields: nearly 100%) and nitrate-nitrogen was measured by volumetric titration using methyl red and bromocresol-green mixture as a color indicator. The analytical accuracy for the overall procedure using our protocol is ±2%.
a)
For determination of δ15N values of nitrate in the extract, nitrate was first transformed into ammonia as described above, and finally transformed into ammonium sulfate under slight excess presence of sulphuric acid on a GF/F glass filter. 15N/14N ratios for the samples were measured by a continuous-flow mass spectrometer (GV Instruments, Manchester, UK) coupled with an elemental analyzer. All isotopic values were shown as common δ15N notation, per mil deviation relative to international standard; atmospheric nitrogen. The analytical error during the overall process of mass spectrometry is less than ±0.2‰. K in the filtrate was determined by atomic absorption spectrophotometry (AAanalyst 100, PerkinElmer, Massachusetts, USA). Error in the quantitative analysis for K was estimated at ±5%. Quantitative determination of Rb and Sr was made on samples of 130 to 150 mg aliquots. The samples were dissolved in 1 M HCl solution followed by evaporative concentration and re-dissolution. The resulting solution was applied using Muromac column chromatography packed with the AG500W 12X 200–400 resin (Bio-Rd lab.). Sr-containing elute was again evaporated. All the fractions were smeared on a single tungsten filament. 87Sr/86Sr was determined with a Varian MAT262 mass spectrometer. An international Sr standard (NIST SRM987) gave 87 Sr/86Sr ratios of 0.71022 to 0.71023 during the measurement. Historical documents kept in the custom house at Nagasaki harbor, Japan (present-day Nagasaki Museum of History and Culture; Document Numbers: B14-33-1-1, B14-33-1-2, B14-34-7-1, B14-34-7-2, B-14-171-31 and B14-171-3-2 written in old Japanese) and British parliamentary papers (Irish University Press, 1971) were examined for records of saltpetre importation from 1859 to 1870. The former documents are daily records (Fig. 2), where the latter are annual records, respectively. Old Japanese systems for weight presentation were converted into current tonnages. 3. Results and discussion 3.1. 14C age determination (Table 1) Age control is a prerequisite for studies on the historic cultural properties. High precision accelerator mass spectrometry (AMS) has
b)
Fig. 2. (a): A photo showing the cover page of the file of custom documents (Document number: B14-171-3-1) kept at the Nagasaki Museum of History and Culture at Nagasaki. The surface letters written by free-hand Japanese (in vertical direction) indicate the document start from the first January to the end of June, 1867. (b): First example of the application form for the purchase of saltpetre compiled in the file. The free-hand written Japanese letters (in the vertical direction) located on the mid-line indicate that the Kumamoto domain is applying 30 t of saltpetre through a German merchant, Kniffler Co. on the 5th of January, 1867. The corresponding receipt is not attached on the following pages.
C. Mizota et al. / Journal of Archaeological Science: Reports 2 (2015) 532–537 Table 1 Analytical data for 14C dating. Laboratory
Uncalibrated age
Calibrated
Sample
Number
(yr BP ± 1σ)
Date range (2σ)
Wood chips Papers
YU-1857 YU-1630
145 ± 15 135 ± 20
1723 AD–1779 AD 1799 AD–1892 AD
increasingly been used for 14C age determination among the interdisciplinary sciences. The AMS method is applicable for small amounts of carbonaceous materials (0.2 to 2 mg as elemental carbon) aged less than ca. 50,000 to 60,000 years. Whitish salt masses packed in the wooden boxes from the NPTMHF did not contain enough carbon for direct age determination by AMS. Instead, the method was applied to two other samples. Sapwood chips from the outermost part of the liner wall and the detached Japanese traditional paper band yielded the raw radiocarbon ages of 1868 ± 15 (code no. YU-1857) and 1880 ± 20 (code no. YU-1630), respectively. The former age just corresponds to a transitional date from the period of government in Japan by the Tokugawa Shogunate to Meiji Restoration when the abrupt changes in the political regimes occurred. From the data, the age of box production is estimated at close to maximal of the demand for materials in Japan, as described in the Introduction section. The Japanese cover paper attached on the surface of the boxes was aged slightly younger than wooden chips. The paper was probably attached several years after packing of the whitish salty masses. The obtained raw radiocarbon ages are around 1880. The calibrated age ranged is rather extensive (1720 AD to 1890 AD), because this date falls in the middle of a period of extensive carbon pollution caused by the fossil fuel emissions of the Industrial Revolution. As such, raw radiocarbon ages in the 1880s, although indicative, cannot be considered to be very definitive. 3.2. Chemical and nitrogen isotope composition (δ15N) Table 2 shows the chemical and nitrogen isotopic composition of whitish salty masses from the NPTMHF and Bengal niter from the NHM at London. To test the homogeneity, four repeated analysis was made for samples packed in each of boxes A and B. The concentrations of K (38.4%) and nitrate-nitrogen (12.4 and 12.5%) for both boxes were nearly identical, indicating very high homogeneity of content. Since pure KNO3 consists of 38.7% K and 13.9% nitrate-nitrogen, the salty masses demonstrated to be nearly pure saltpetre. Assuming that all the nitrate-nitrogen in the samples are allocated to KNO3, the purity is around 90%. The two authentic saltpetre specimens to be of Bengal origin showed a somewhat lower K content (34.6 and 37.0%) than those from NPTMHF, but slightly higher nitrate-nitrogen in the range of 13.1 and 13.2%. The estimated content of saltpetre in the rough niter specimen (21863) is clearly higher than those reported from four locations in British India (27 to 68%; Leather and Mukerji, 1911). Whitish masses from the boxes A and B gave an identical δ15N value of +13.2‰, whereas those from the Bengal saltpetre specimens (+16.5 and 16.6‰) gave c. 3‰ higher than those from the former specimens.
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Difference between the refined and rough saltpetre samples may be the result of derivation from different lots. Depending on the environmental conditions, the nitrogen isotopic fractionation associated with the microbiological nitrification shows a range of variation from 35 to 60‰ (Robinson, 2001). Such high δ15N values of the specimens substantiate the unique process of the Bengal saltpetre formation, being clearly distinctive from those of local saltpetre prevailing during the middle 19th century in central Japan (Gokayama, Toyama, δ15N values = + 4.7 to + 6.0‰ with an average of + 5.5‰; Mizota and Yamanaka, 2014). Microbial nitrates formed from the residual ammonium (resulting in enrichment by 15N) remaining after the emission of 14 N-enriched NH3 under open air as in British India are a plausible mechanism. Spatial distribution patterns of total inorganic nitrogen deposition in 1860 (Galloway et al., 2004), ammonia and nitrous oxide in free atmosphere (2000; Yamaji et al., 2004), and global ammonia distribution (2008: Clarisse et al., 2009), are all indicative of intensified nitrogen cycles along the Ganga River Valley. As already described in the proceeding section of the Introduction, Bengal saltpetre was a monopoly industry of early modern England. Details on the accounts have been given in several technical papers published in colonial India (Leather and Mukerji, 1911; Hutchnson, 1917). The outline of the production process is briefly summarized below. The ultimate source of nitrogen for saltpetre production is human and animal (mainly buffalo) excreta deposited in the form of the organic nitrogen. Excretion on the ground is customary along the region of the Ganga River plain where the human density is quite high. The organic waste deposited on the ground surface is subject to mineralization, following nitrification under alternating wet and dry weather conditions. The resulting surface soils were enriched by KNO3 which were taken by local saltpetre-men. Rough saltpetre was yielded by water extraction, followed by differential crystallization to remove impurities other than KNO3. The processes involving the nitrification are highly sensitive to environmental factors, particularly soil conditions (soil moisture and temperature regimes) (Aulakh et al., 1992; Mizota et al., 2006), resulting in wider ranges in isotopic fractionation factors, as compiled by Robinson (2001). Thus, literature review of historical documents relevant to the biotechnology supports the observed nitrogen isotopic variation for the NPTMHF and the NHM at London. 3.3. 87Sr/86Sr ratios Saltpetre manufacture involves the dissolution and re-crystallization from the concentrated KNO3 solution where meteoric ground/or river waters are used. The resulting saltpetre commodity contains strontium as a minor constituent. Table 3 summarizes the content of rubidium and strontium together with strontium isotope composition. The content of rubidium in the selected saltpetre samples (22.2 to 44.8 ppm; samples from the NPTMHF and acquisition number 21863 from the NHM at London) is two orders of magnitude higher than that of the associated strontium (0.17 and 0.74 ppm). Saltpetre specimens (salt in the Boxes in A and B and Bengal saltpetre: specimen number of 21863) gave 87 Sr/86Sr ratios in range from 0.714923 to 0.722575, exhibiting a trend of higher values in rough samples than those of refined specimens. These strontium isotopic values are nearly consistent with those reported
Table 2 Averaged chemical and nitrogen isotopic compositions of samples. Host institution
Nagasaki Prefectural Tsushima Museum of History and Folklore Natural History Museum (London) a b c
Refer Fig. 1a. A: right box, B: left box. Refined niter of detached single crystals (refer Fig. 1b; upper box). Rough saltpetre (refer Fig. 1b; minute crystals in the lower box).
Group or code No.
Whitish mass in Box Aa Whitish mass in Box Ba Bengal niter 21840b Bengal niter 21863c
Numbers of analysis
4 4 2 3
Content (w.%) K
NO− 3 -nitrogen
δ15Nnitrate (‰)
38.4 38.4 34.6 37.0
12.5 12.4 13.1 13.2
+13.2 +13.2 +16.5 +16.6
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4. Conclusion
Table 3 Concentration of Rb and Sr,and 87Sr/86Sr ratios for samples. Samples
NPTMHF NHM in London
No.
Box A Box B 21840a 21863a
Numbers of analysis
1 1 1 1
Content (ppm)
87
Sr/86Sr
Rb
Sr
Ratios
Error
nd 22.2 33.3 44.8
nd 0.17 2.64 0.74
0.715325 0.714923 0.708133 0.722575
0.000014 0.000011 0.000012 0.000010
nd = not determined. a Refer footnote in Table 2.
from the dissolved strontium in Ganga river waters collected near Patna (0.7168 to 0.7400; Krishnaswani et al., 1992) where the intensive saltpetre industry existed, but distinct from those of the wide-spread spring and mineral waters throughout the Japanese Islands (0.703 to 0.712; Notsu et al., 1991), probably young age of bedrocks. One refined Bengal saltpetre specimen (specimen number: 21840) showed a different trend from those other specimens, giving 87Sr/86Sr ratio of 0.708133. Such a low value probably indicates secondary incorporation and exchange with local strontium during the processes of dissolution and subsequent re-crystallization. Strontium isotope composition of mineral water throughout the United Kingdom is documented (Montgomery et al., 2006). The strontium isotope ratios of the mineral water available to the major saltpetre refineries (Faversham (Kent), Waltham Abbey (Essex), and Chilworth (Surrey) in England: Cressy, 2011) are nearly 0.7077, reflecting the young bedrock ages.
3.4. Examination for the historical documents kept at custom house in Nagasaki and British parliamentary papers during 1859 to 1870 Once we had established the identity of the whitish salty masses kept in the NPTMHF as the economic saltpetre with British Indian provenance prevailed during the middle 19th century, the historical documents provided additional evidence for the marketing route. Tsushima Island is near Nagasaki harbor (32°44′ N, 129°52′ E) which was a major trading port. Table 4 summarizes the annual importation of saltpetre at the Nagasaki harbor which had the facility to trade with foreign countries. Close examination for the harbors like Kanagawa (presentday Yokohama) and Hakodate (southern Hokkaido) shows that they do not have any records of the importation during the appropriate time (Irish University Press, 1971). There can be seen a clear trend on the temporal changes in the data. The British parliamentary papers always gave higher figures, relative to the corresponding year for the custom house at Nagasaki. Such a discrepancy could not be understood at the moment. Probably, custom at Nagasaki did not function well at the time. Amounts of the imported saltpetre abruptly increase from 1867 (168 t; custom house at Nagasaki) or 1866 (351 t; British parliamentary papers), until 1870 with a maximum in 1867. The maximum corresponds to just one year before the initiation of the Boshin War (civil war) when the domestic demand for saltpetre attending its maximal in Japan. The chronological trends well explain the 14C ages for the production date of wooden box, as described above.
Table 4 Temporal changes in the annual amounts of imported saltpetre at Nagasaki harbor. Estimates on the imported saltpetre (tons/year) Calendar year
Custom house at Nagasaki
British parliamentary papers
1865 1866 1867 1868 1869 1870
None None 168 40 36 None
None 351 436 200 150 None
A large-sized, section of economic saltpetre for gunpowder ingredients was excavated from the store house of the NPTMHF. Chemical and isotopic analyses as comparing this with those from the two types (rough and refined) of authentic Bengal saltpetre (NHM) revealed it as from British India during the middle 19th century. The rough saltpetre matches the expectation that it comes from British India, while the refined saltpetre should have faced some post-collecting alteration in the dissolving and refinement processes within the United Kingdom. Historical documents recorded at the custom house in Nagasaki harbor and British parliamentary papers support the validity of the interpretation based on the geochemical evidence. The most probable route of the transportation is that historic saltpetre first produced in British India along the Ganga River Valley and transported to be refined in the United Kingdom, then exported to Nagasaki. Acknowledgments Bengal saltpetre specimens were kindly donated by mineral curator, Dr. Peter Tandy, of the Natural History Museum at London. English on the early version of the manuscript was improved by Dr. A. L. Cronin (Iwate University). We are grateful to them. References Aulakh, M.S., Doran, J.W., Mosier, A.R., 1992. Soil denitrification: significance, measurement, and effects on management. Adv. Soil Sci. 18, 1–57. Buchanan, B.J., 2006. Saltpetre: a commodity of empire. In: Buchanan, B.J. (Ed.), Gunpowder, Explosives and the State: a Technological History. Ashgate Publishing Limited, England, pp. 67–90. Capo, R.C., Stewart, B.W., Chadwick, O.A., 1998. Strontium isotopes as tracers of ecosystem processes: theory and methods. Geoderma 82, 197–225. Clarisse, L., Clerbaux, C., Dentener, F., Hurtmans, D., Coheur, P.-F., 2009. Global ammonia distribution derived from infrared satellite observations. Nat. Geosci. 2, 479–483. Cressy, D., 2011. Saltpetre, state security and vexation in early modern England. Past Present 212, 73–111. FitzGerald, W.G., 1895. How explosives are made. Strand Mag. 9, 307–318. Frey, J.W., 2009. The Indian saltpeter trade, the military revolution, and the rise of Britain as a global superpower. Historian 71, 507–554. Galloway, J.N., et al., 2004. Nitrogen cycles: past, present, and future. Biogeochemistry 70, 153–226. Goodenough, R.A., 1868. Notes on Gunpowder. The Royal Artillery Institution, Woolwich and London, United Kingdom, pp. 1–52. Gray, E., Marsh, H., McLaren, M., 1982. Review. A short history of gunpowder and the role of charcoal in its manufacture. J. Mater. Sci. 17, 3385–3400. Hutchnson, C.M., 1917. Saltpetre: its origin and extraction in India. Bull. Agric. Res. Inst. Pusa 68, 1–24. Irish University Press, 1971. Irish University Press Area Studies Series, British Parliamentary Papers, Japan 4. Embassy and Consular Commercial Reports, 1859–1871pp. 1–590. Kaneko, M., Poulson, S.R., 2013. The rate of oxygen isotope exchange between nitrate and water. Geochim. Cosmochim. Acta 118, 148–156. Krishnaswani, S., Trivedi, J.R., Sarin, M.M., Ramesh, R., Sharma, K.K., 1992. Strontium isotopes and rubidium in the Ganga-Brahmaputra river system: weathering in the Himalaya, fluxes to the Bay of Bengal and contributions to the evolution of oceanic 87 Sr/86Sr. Earth Planet. Sci. Lett. 109, 243–253. Leather, J.W., Mukerji, J.N., 1911. The Indian saltpetre industry. Bull. Agric. Res. Inst. Pusa 24, 1–19. Marshall, A., 1917. Explosives. Second Edition History and Manufacture vol. 1. J. & A. Churchhill, London, pp. 1–407. Mizota, C., Yamanaka, T., 2014. Stable isotopic characterization of gunpowder ingredients from the mid to late nineteenth century in Japan. J. Archaeol. Sci. 45, 90–95. Mizota, C., Yamaguchi, Y., Noborio, K., 2006. Microbial transformation of nitrogen in cattle slurry as applied to an Andisol grassland. J. Jpn. Soc. Soil Phys. 104, 13–26. Mizota, C., Yamanaka, T., Ichinose, A., 2014. Provenance of historic gunpowder from south-western Japan: a stable isotopic approach. Archaeometry http://dx.doi.org/ 10.1111/arcm. 2141 (Available online). Montgomery, J., Evans, J.A., Wildman, G., 2006. 87Sr/86Sr isotope composition of bottled British mineral waters for environmental and forensic purposes. Appl. Geochem. 21, 1626–1634. Nisi, G.B., Buccianti, A., Vaselli, O., Perini, G., Tssi, F., Minissale, A., Montegrossi, G., 2008. Hydrogeochemistry and strontium isotopes in the Arono River Basin (Tuscany, Italy): constraints on natural controls by statistical modeling. J. Hydrol. 360, 166–183. Notsu, K., Wakita, H., Nakamura, Y., 1991. Strontium isotopic composition of hot spring and mineral waters. Jpn. Appl. Geochem. 6, 543–551. Reimer, P.J., Baillie, M.G.L., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., Burr, G.S., Edwards, R.L., Friedrich, M., Grootes, P.M., Guilderson, T.P., Hajdas, I., Heaton, T.J., Hogg, A.G., Hughen, K.A., Kaiser, K.F., Kromer, B., McCormac,
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