Finally, we consider two variables that will attract more attention than most. First, we use the data variable
“African resistance” (RESISTANCE) to compute a “Rate of Resistance” variable which is available only on the time
line and in Custom Graphs. This is simply the number of vessels experiencing some recorded act of resistance
divided by the total number of vessels in a given year and expressed as a percentage. The second is the “Sterling
cash price (of slaves) in Jamaica” variable (JAMCASPR), which may be used to track the price paid for slaves in
the Americas as they were sold from the vessel. The Voyages Database contains prices for those on board 959 voyages.
The full derivation of these data is described elsewhere, but a summary description is appropriate here.
(23) Prices for human beings in the Americas were subject to as many
influences as were prices in any other market. Key factors included the characteristics of the person being
sold, the distance between slave markets in the Americas and Africa and the price of the captive in Africa.
This variable attempts to adjust for several of these factors so that the underlying price trends become
apparent to the user of Voyages. In most cases the data are taken from the slave traders’ accounts and
correspondence. Our first goal was to ensure that we recorded a single category of captive – what was
frequently referred to at the time as “a prime male”.(24) Second, we adjusted
that price for the price differential between the market in which the slave was actually sold and the price in
Jamaica. Thus, if the captive was sold in one of the eastern Caribbean islands we would make a small adjustment
upwards to reflect the ten extra days sailing time it would take to reach Jamaica. Third, we converted all
prices into pounds sterling. What we did not do was to express the price in constant pounds (adjusted for
inflation) – in other words, in real terms. This variable is thus based on archival data, but the adjustments
we have made in the interests of making it intelligible for users have the effect of converting this into an
The above discussion is not exhaustive in the sense that we not have touched on and explained every single
variable in either the Voyages interface or the two databases offered for downloading. Many of the variables
need no more explanation than is available on the Variable List page and readers are referred to this page
for any missing explanations in the preceding pages.