Domestic Trade and Transport, Domestic Industries, Agriculture and Fisheries

Van Zanden and Van Leeuwen only explain how they calculated value added for domestic transport. They do not do so for domestic trade. However, we think it is possible to come to an estimate of the proportion of value added of domestic transport, trade and processing taken together. For most slave-based domestic activities, it is not possible to separate out these element. We therefore in most cases will have to make do with assumptions on the combined contribution of these activities, taking care not to include elements of the total revenue that have been subsumed elsewhere, primarily under international trade, and realizing that this part of our calculation remains somewhat more speculative.
The first component of slave-related domestic trade and transport consisted of the inland distribution of slave-produced sugar (raw and refined), coffee, and lesser slave-produced trade goods.

• For coffee, Tamira Combrink calculates that in 1770, the total value of slave-based coffee imports stood at fl.10.2 million, while coffee exports valued fl.7.5 million, leaving fl.2.7 million for inland consumption. Based on a (admittedly, very limited) amount of observations of prices for coffee retail, she calculates a total value added for roasting, inland trade and transport of 47 per cent on top of the bourse price.
  Factoring in spoilage and other losses accrued in the process of selling the coffee, it seems safe to assume that inland traders, transporters and roasters received 33 per cent on top of wholesale prices of all the coffee on the domestic market, making for a total sum of fl.891,000, of which we estimate 50 per cent to have consisted of wages and profits for the trading houses, inland transporters, retailers, etc. This sum for the Netherlands as a whole can then be transferred to an amount for the province of Holland based on rough population estimates (40 per cent), assuming that per capita consumption of coffee in urbanized Holland was as high as in the rest of the Netherlands (which is probably an underestimation for Holland), leading to a total of fl.178,000.
• For sugar, Tamira Combrink calculates that in 1770, slave-based imports of raw sugar valued fl.11.3 million, while slave-based sugar exports totalled fl.10.1 million.
  However, import and export values do not yet give a figure for domestic consumption, due to the fact that most sugar underwent industrial refining, which added substantially to the value of the product, while at the same time resulting in considerable weight loss between raw material and end product. Taking into account both factors, Combrink estimates the value of sugar traded and consumed inland at fl.4.3 million. On top of the value added in refinery (which we have factored in under a different post), Combrink estimates 17 per cent of consumer prices going to retail as a whole, including transport and domestic trade. Once again estimating half of this sum to have consisted of wages and profits, the total value added in the domestic sugar trade can be estimated at fl.366,000. This sum for the Netherlands as a whole can then be transferred to an amount for the province of Holland following the same assumptions as under coffee, leading to a total of fl.146,000.

• Apart from coffee and sugar, the Dutch imported slave-produced tobacco, indigo, cotton and cacao. Most of the tobacco imported in the Netherlands came from Virginia and Maryland. Part of this was processed for re-export, and another part was processed for domestic consumption. For lack of more reliable data, we estimate a total contribution in value added for tobacco on the basis of what we know about the size of the tobacco processing sector. According to one contemporary estimate, Rotterdam as the main centre of colonial tobacco imports at the end of the eighteenth century employed 3,500 workers in the tobacco processing industry. These workers processed inland tobacco as well as colonial tobacco, at a proportion of 1:2.
  Roessingh questions this figure, so to be on the safe side it might be better to take this as the total number of workers employed in tobacco processing in the whole of Holland.27 If we conservatively estimate the value added in this branch of industry as
  0.33 times the number of workers it employed at a yearly wage of fl.180, tobacco processing added fl.210,000 to Holland’s GDP. For lack of data, we make a guestimate that the inland processing, transport and retail trade of all lesser colonial goods combined added fl.300,000 to the GDP of Holland.
  The second component of slave-related domestic production, trade and transport consists of the proportion of the trade goods exported to the Atlantic colonies that were produced in Holland, as well as the domestically produced goods used in the Dutch slave trade and the slave trade of other European nations. Under international trade, we have already presented our estimates for the total size of these trade flows: fl.1.5 million in products produced in the Dutch Republic for the Atlantic colonies, fl.225,000 in domestically produced goods for the Dutch slave trade, and fl.500,000 in domestically produced goods for the slave trade of other nations. Adapting trade flows to and from the Dutch Republic to flows to and from Holland, we use the values γ mentioned in Table 4, giving a total of fl.1.17 million in goods exported from Holland to the Atlantic colonies, and fl.550,000 exported from that province for the slave trade. However, since this is calculated on the basis of end prices in export that already contain a value added element, we have to deduct roughly 60 per cent in order to avoid double counting. If the value added in domestic production, trade and transport amounted to 80 per cent of the pre-export value of these goods (a high proportion that reflects the fact that the entire value chain for these goods was domestic), they contributed fl.550,000 to the GDP of Holland.
• The third component of the value added in the domestic sector is formed by victuals and other supplies to the merchant ships active in slave-based trade. This can only be calculated on an extremely tenuous basis. Many, though certainly not all, of the victuals and other goods necessary for the equipment of transcontinental voyages were produced locally. Apart from domestic trade and transport, these also contributed to the agrarian sector and food-processing industries such as bakeries and brewers. Just like in the case of the domestically produced goods exported to the colonies, only very rough measures are available. The MCC provides the best proxy. Gerhard de Kok has reconstructed the accounts for all MCC voyages, 30 of which took place in the 1770s. On average, fl.50,211 per journey was spent on operational costs (the figures excludes the costs of shipbuilding, masts and rigging, etc., thereby avoiding double counting with the shipbuilding sector). Of these, fl.17,471, or 35 per cent of the operating costs consisted of victuals and other necessities.
• Sailors’ wages are excluded from this total, since in the approach of Van Zanden and Van Leeuwen they belong to value added in the shipping sector. Using Van der Oudermeulen’s 1780 figures for trans-Atlantic voyages, and adjusting these for the smaller size of Atlantic trade in 1770 according to the proportion mentioned in Table 2, we estimate 163 slave-based Atlantic voyages to have taken place that year, which would have required 163.17,471 = fl.2.85 million in victuals, 78 per cent of which were destined for voyages leaving from or arriving in Holland. If 75 per cent of the inputs were produced locally in Holland (a realistic proportion given the dominance of domestically produced goods in sailors’ rations), with 80 per cent of their total value counted as value added in domestic production and agriculture, trade and shipping, this adds another fl.1.33 million to the GDP of Holland.
• The total value added in agriculture, industry (excluding shipbuilding and sugar), inland trade and shipping from slave-based activities in this way comes at fl.2.5 million.