Where can I get
help using this website?
On the right side of the orientation bar beneath
the top banner, there are links to four different types of online
- a Sitemap showing all areas of the site at a
- a list of frequently asked questions and answers
- video demonstrations of how to use the website and
- a Glossary of terms used in the study
of the slave trade.
Additionally, in the Understanding the Database
area of The Database section of the site, users can access a guide to
understanding and using the online database and the website, including
How do I find out
what’s available on this website?
The five main sections of the website
are listed in the blue banner at the top of the screen: The Database; Assessing
the Slave Trade; Resources; Educational Materials; and About the Project.
Clicking on the name of one of these sections opens a page with general
information about the section and its principal subsections. If you are visiting
this site for the first time, you will find it useful to read this introduction.
The sitemap, located on the right side of the orientation bar beneath the top
banner, provides an at-a-glance list of the sections and subsections of the
How do I move
from one part of the website to another?
From any page of the website, you
can move to another page by clicking on one of the five labels in the top
navigation bar (or items in the drop-down menus associated with them). You can
also use the sitemap among Help options, or click on part of the path in the
orientation bar. Once in a section, you can quickly move to a subsection within
it by means of links in the left frame.
What are the
optimal settings for viewing the website?
The performance of the Voyages
website has been tested for compatibility with Mozilla Firefox 2, Microsoft
Internet Explorer 7, and Safari 3. Interactive features like timelines and maps
older than three years. The website is designed for a screen resolution of not
less than 1024x768 and 32-bit depth. For full display of pages, you may need to
disable unnecessary toolbars or side panels in your browser.
Can I reuse or
republish any information or materials I find on this website?
Voyages website supports education and research by making its information
available for free. Much of the information is protected by copyright. An
Attribution-Non-Commerical Creative Commons license governs much of the content
on the site, including historical and imputed data found in the three main databases
on the site – the Voyages Database, the Estimates Database, and the African
Names Database. This license allows for the non-commercial republication of certain
content on the site and the creation of derivate works, provided the Voyages
website is appropriately credited as the original source. Some materials on the
Voyages website, however, appear by permission of the copyright owners and
require their approval before being republished. For a guide to the various content
on the site, permissions governing their use, and examples of how to cite the
original source, see the "Permissions to Reproduce" section of the "Legal" page.
What is the
difference between a data variable and an imputed variable?
variable is one that is documented directly from one of the primary sources that
provide evidence of a slaving voyage. An imputed variable is not
documented directly, but is inferred by historians from data variables. The
essay, “Construction of the Trans-Atlantic Slave Trade Database: Methods and
Sources,” located in “Understanding the Database,” a subsection of “The
Database,” explains the assumptions and basis of all imputed variables. On the
website, they are indicated by an asterisk following the variable name.
Variables with asterisks are imputed. Variables without asterisks are data
What is the
difference between basic variables and general variables?
There are two
main options for querying the database: a basic search (“Basic
variables”) uses a smaller set of variables, and a general search
(“General variables”) uses an expanded set of variables. Basic variables are
one-third of the total number of variables in the database, and general
variables are a more extensive list of variables (though fewer than the over 200
variables available by downloading the full SPSS dataset).
Why is there an
asterisk (*) next to some variables?
Variables with an asterisk are
imputed. Imputed variables do not refer to information found in a source but to
information inferred by historians from information that is found directly in
sources. Data variables (variables in the database without asterisks) are
documented directly from primary sources that provide evidence of a slaving
voyage. For example, historical documents rarely indicate that a port where
slaves disembarked was the principal place of landing, but when documentation
exists on the number of slaves disembarked at several ports, the historian can
determine where the largest number were disembarked, the principal place of
disembarkation for the voyage. In some cases, how many slaves embarked is
documented, but not how many disembarked. From the survival rate on voyages with
the same characteristics, we impute the number who did so on the voyage with
missing information. The essay, “Construction …: Methods and Sources,” explains
the assumptions and basis of all imputed variables.
Where can I see
at a glance variables available for analysis in different sections of the
Look in the fourth, fifth, and six columns of the Variable List.
The column “Voyages” shows the number of cases that have information coded for
each variable in the main database.
How can I observe
the values of a variable?
For categorical variables, put the variable into
Current query. You will see it there with the notation [nothing selected].
Clicking on select will review the variable’s values. For seeing how many cases,
or slave voyages, are coded for the variable, put a mark in the check box and
look at Results, at the bottom right of the query box. For numerical variables,
one way to observe the range of values is to select the variable for display in
the Results tab by using “Configure columns” (top right of main display area,
opposite List of voyages) and then sort (clicking on the column heading) to see
the top and bottom of its range.
Where do I find
bibliographies of studies of the slave trade on the website?
secondary sources,” the fourth part of Sources in Understanding the Database, a
subsection of The Database, provides a comprehensive bibliography of scholarly
studies of the Atlantic slave trade.
How do I find
documentation for a particular voyage?
Your starting point should be the
“Sources” for the voyage cited in the Trans-Atlantic Slave Trade database. These
are listed in the last of the “Voyage variables” in Voyage detail, accessed by
clicking on the row listing a voyage under the Results tab in Search the
Database. Pop-up windows explain the short references; but full references are
found in Sources in Understanding the Database, where the short references can
be used to bring up the full description of the source.
How do I find
information about a particular slaving voyage?
“Search the Database”
enables you to identify one voyage in particular. If you know the name of the
vessel, click on “Vessel name” in the category “Ship, nations, owners” in the
query frame. That will open a space in the Current query box to enter the name.
Then click on search. As many ships made more than one slaving voyage and others
shared the same name, you may well find more than one ship with the name you
entered. Check the year the voyage arrived or other information which permits
you to distinguish it from others with the same name. Clicking on a particular
voyage in the Results listing will open a window with voyage known
How do I limit
queries to specific sets of years?
“Select time frame” is the first query
box at the top of the left frame in both the Voyages Database and Estimates. In
Estimates, the default setting is 1501 to 1866 since evidence points to
disembarkation of African slaves in Hispaniola from the beginning of the
sixteenth century. For the Voyages Database, the time frame is set by default to
the period from 1514, the first year in which a slave voyage can be documented,
to 1866, the year of arrival of the last three documented slave voyages. For a
single year, specify the same year in both “From” and “To.”
How do I select
voyages for examination and analysis?
First, from the set of either basic
or general variables, select a variable to limit the search by the criteria
represented by its values. You do this by clicking on it in the roll-over menu
that lists variables in one of eight categories (Ship, nation, owners; Outcome
of voyage; etc.). This will move the variable into the box for “Current query.”
Clicking on “Select” here opens a space for limiting the query to certain cases
by using the variable. Make your selection and click on OK. You can then further
limit the query by using another variable. Again, click on OK once you have made
a selection. When you have finished entering criteria of selection, click on
“Search” to activate the query. You will see to the right a list of voyages that
match your selection criteria.
Is there a way
to know how many cases in the database have information relevant to a particular
Every choice of criteria limits the query to a smaller number of
voyages. As you are making a selection, you can see how many voyages satisfy
your criteria by viewing the number after “Results” at the bottom right of the
“Current query” Box.
Why do methods
of selection differ from variable to variable?
The method of selection
depends on the type of variable. If it is numerical, like “Voyage identification
number” or “Year arrived with slaves” or “Total slaves embarked,” one is asked
to enter a specific number or range of numbers. If it is a name, like that of a
ship or its captain or the owner of the venture, one is asked to enter the name
or part of it. If the variable consists of a set of categories, such as places
or types of outcome of a slaving voyage, then the categories are listed with
small check boxes in front of them and one is asked to check those that
correspond to categories about which to find information. If there is an
arrowhead in front of the checkbox, click on it to reveal further
How do I use
selection options for numerical variables?
Numerical variables ask the
user to choose one of four options and enter a number or numbers after it:
- At most
- At least
- is equal to
For percentages and rates, enter “At least ‘0’” to limit the query to
voyages for which such measures can be computed.
“Previous queries” work?
You can recall the selection criteria in a
previous query in the current session by opening the “Previous queries” box and
clicking on “restore.” If the box becomes cluttered with too many previous
queries, you can remove any of them by clicking on “delete.” This option works
only during a single session. When you close the browser window with the
website, your previous queries disappear. For a permanent record of a query, use
the option “Create a link.”
How does “Create
a link” work?
“Create a link” appears in the left frame of “Search the
Database” after one has clicked on “Search” to execute a query. It creates a URL
which users can save and later recreate the query by pasting in the site’s
How do I select
variables of names (of the ship, captain, owners) and sources?
the variable in the set of Basic or General variables. It will open a space to
enter the name or part of the name. The query program will list all records
containing the sequence of letters you enter after click on “Search” to activate
the program. Searching for a source is slightly more complicated because it
requires one to enter its short reference rather than the full reference. To
find voyages described in a particular source, begin by finding it in the
bibliography of “Sources” in “Understanding the Database.” Note that the list of
sources can be sorted by either short or long reference.
How do I control
for certain variables in analyzing data in other variables in the main database
A control variable is one that does not change (or is held
constant) during analysis of data in order to minimize its effect on results.
The reason for doing this is to see more clearly the effects of other variables.
Consider the following example. In the Voyages Database, a researcher wishes to
examine differences in mortality on slave voyages organized in Great Britain and
mainland North American colonies. She begins by setting three criteria in the
query frame: a) time frame: 1700-1749; b) place where voyage began: Great
Britain (clicking on Great Britain, England, Scotland, and Ireland); and c)
outcome of voyage for owners: Delivered slaves for original owners. Time frame
is selected because the researcher wants to see if any difference between
British and American voyages persisted over time. She plans to obtain results
first for the period 1700-49, and then for 1750-99. The second variable, where
the voyage began, is the one whose effect on mortality the researcher is
interested in. The third variable, outcome for owner, is the control variable.
It will not change throughout the analysis. It affects the results, but the
researcher is more interested in the effect of the place where the voyage was
organized. By limiting the analysis only to voyages completed as the owner of
the venture intended, the researcher is able to eliminate the effect on results
of other possible outcomes, such as shipwreck or capture at see by an enemy
What does the
command “New query” do?
This command resets the query interface to its
initial setting, containing all 34,941 voyages in the database. Otherwise,
previous specifications remain in effect. If you find less than all voyages or
some specifications already set at the beginning of a session, the reason is
probably information in your cache from previous sessions which prevents you
from making a clean start.
When I begin a
new session on the Voyages website, I find that it does not open with default
settings, but instead some settings resulting from queries made in the preceding
session remain in effect. How do I begin again from default?
on “New query” in the “Current query” box. Normally, it will return you to
default settings and to the first page (Results) of Search the Database. If it
does not do this, another more roundabout way to get to default settings is to
close the browser window (not just a tab since the browser may retain the
session state until it is completely exited – indeed, it may be necessary to
definitively end a browser session by use of the Task Manager), reopen the
browser, clear its cache, and then return to the Voyages website.
How do I
interpret information provided in “Summary Statistics”?
First, you should
be aware that the statistics for slaves embarked, disembarked, and the
percentage who died during the Middle Passage are calculated from imputed
variables in the data set. Totals are somewhat less, and averages somewhat
different, when based on data variables: 331 slaves embarked, 277 disembarked,
and 10.9 percent mortality. The other four summary statistics (length of Middle
Passage, percentage of children and males, and tonnage) are calculated from data
How can I use
“Summary Statistics” in combination with the query frame to the left to compare
voyages with different characteristics?
The default for “Search the
Database” is the complete database. Thus, when no criteria of selection are
specified in the query frame, the summary statistics describe the entirety of
the slave trade. While in summary statistics, however, you can select voyages in
the query frame at the left to see how they compare with the general average in
the entire data set. For example, to answer the question, did the average number
of slaves embarked on slave voyages decline or increase in the era of abolition
after 1808, simply change the time frame on the left to 1808 to 1866 and click
“averages” calculated in Summary Statistics, Tables, and the Timeline mean?
An average is a value that is typical or representative of all values for
the group of persons or things it describes. It is important to remember that
the meaning of an average should be judged by the amount of deviation of
particular cases around it. For four voyages landing 250, 280, 310, 360 slaves
respectively, and for three voyages with 100 slaves and one voyage with 900, the
average is the same: 300 slaves. The standard deviation is the clue to how much
the average resembles particular cases in the group for which it is calculated.
Divide the standard deviation by the average. The smaller the quotient, the
closer particular cases are to the average. The larger the quotient, the more
variation there is above and below the average.
How do I
determine if a slaving voyage is typical or exceptional?
statistics for the voyage, as shown in Voyage detail, to summary statistics for
all voyages or voyages of the same type. All voyages are usually too large a
reference group to be a meaningful unit of comparison. It is more revealing to
determine if a voyage is typical of others under the same flag, or from the same
period of time, or following the same route from a region in Africa to a region
in the Americas.
What can be
learned by graphing differences observed in tables?
Graphs can bring to
the researcher’s attention patterns that might not be observed simply scanning
the statistics contained in a table. Tables also present the danger of tempting
the researcher to exaggerate the importance of small differences. If differences
are too small, or patterns too indistinct, to be clearly observed in a graph,
they are usually not significant.
offer the possibility to construct three kinds of graphs: XY, pie, and bar
charts. When should I use each type?
First, read over the answers to the
FAQs about how to construct the three kinds of graphs. Each begins with a simple
definition of the graph type. In general, bar charts are appropriate for
comparing two to ten categories that can be measured numerically; pie charts are
appropriate for comparing percentages of a whole; and XY charts show the
relationship, or correlation, between two numerical variables.
Is there a
technique for making effective graphs?
Remember that a limited number of
categories of comparison is necessary for both bar and pie charts. Too many
categories make a chart difficult to interpret. If you find this to be the case,
use the left query frame to limit the number of categories or values to a
manageable number. A bar chart is useful for comparing several categories on a
numerical scale, for example, the number of voyages on British and Dutch vessels
in the period 1641-1700, when development of sugar colonies in the Caribbean
began, or number of slaves embarked in different regions of Africa, or the
average size (in tons) of United States and British ships. Number of voyages,
slaves embarked, and tonnage are all numerical variables. Flag or nationality
and region are categorical variables. Use of the query frame to limit
categories represented in a bar or pie chart is a key to making effective use of
How do I
construct a bar chart?
First, select bar chart as the “Graph type.”
Second, choose a categorical variable for the X (horizontal) axis. Third, select
for the Y (vertical) axis a variable that can be measured for each category and
add it to “Current series.” Several series can be included in the graph if one
wishes to do so, but they must be similar. Any series can be removed from
“Current series” by checking the box next to it and clicking on “Remove
selected.” Once all specifications are made, click on “Show.” If the resulting
graph is not satisfactory, rethink your specifications.
How do I make a
A pie chart is a circular graph having radii dividing the
circle into sectors proportional in area to the relative magnitudes, frequencies
or percentages represented. "Voyages" allows users to analyze data using a pie
chart in the "Custom graphs" section. Pie charts effectively depict
To make a pie chart in Custom Graphs, click on its button
among graph types; enter under X axis the variable whose values will represent
slices of the pie; and use the Y axis to choose a variable to determine how the
size of each slice will be measured. Click on “Add series” to put it in the
“Current series” box. If another variable is there, remove it. Then click on
“Show.” Only categorical variables are suitable for a pie chart, and not every
categorical variable at that. It is important to choose a variable with a small
enough set of values for pieces of the pie to be more than thin
slivers. Remember that you can limit the number of values in the query frame on
How do I draw an
An X-Y chart consists of a line drawn between the co-ordinates
of values of two numerical variables – one on the X (horizontal) axis, the other
on the Y (vertical) axis. X-Y charts effectively display changes over time, with
a year variable plotted on the x-axis. However, any two numeric variables that
might be correlated can be plotted against each other on this type of chart, for
example, Middle passage (days) and (Avg)Percentage of slaves embarked who died
on voyage. Remember, too, that the query frame on the left can be used to
further refine conditions for observing the correlation between two numeric
What kinds of
maps are found in the website?
The map on the home page is a historical
map in the sense that it is an artifact from the period of the slave trade. It
is part of the world map Nova totius terrarium orbis geographica ac
hydrographica tabula, drawn by the Dutch cartographer Willem Janszoon Blaeu
and first published in 1606. The Introductory maps in the section “Understanding
the Database” are historical in another sense. They provide a cartographical
view of the history of the slave trade. The nine introductory maps are among
more than 150 that will appear in the Atlas of the Slave Trade that will
be published soon by Yale University Press. Among the details about a particular
voyage provided when one clicks on a row in “List of voyages” on the default
page of the Voyages Database is a “Voyage map.” Clicking on the tab of that name
in “Voyage detail” displays a map showing the itinerary from where the voyage
began to where slaves were purchased to where they landed to where the ship
returned to complete an expedition, along with other information when available.
Both the Voyages Database and Estimates have maps which allow the user to
picture the size and structure of the slave trade as defined by criteria of
time, space, national carrier, and other variables in the data set. See the
Guide and responses to other FAQs for more information on how to use their
Is there any
difference between maps in the Voyages Database and in Estimates?
and options for maps in both sections are similar, but there are two important
differences. The Voyages Database permits users to put dots on maps
corresponding to three levels of detail in labeling: broad regions, regions, and
places or ports. In Estimates, only dots for broad and specific regions appear
on maps. Embarkation regions in Africa are the same in the two sections, but
broad disembarkation regions are slightly different. In the Voyages Database,
there are six: Europe, Africa, Brazil, the Caribbean, Spanish Central America,
and Mainland North America. In Estimates, the Caribbean is further distinguished
by the major powers holding slave colonies there: Great Britain, France, the
Netherlands, and Denmark. Colonies in the Guianas are included in the Caribbean.
Spanish Americas combines Spain’s Caribbean colonies (Santo Domingo, Cuba, and
Puerto Rico) with its mainland colonies, in Central America and in the Rio de la
Plata basin. Specific regions within Mainland North America, the British,
French, and Danish Caribbean, and the Dutch and Spanish Americas, are also
defined somewhat differently in Estimates than in the Voyages Database.
interactive maps affected by selections made in the query frame on the left?
Any change in criteria used to select voyages also changes the
representation of places of embarkation and disembarkation by yellow and red
dots on the map and the meaning of the size of the dots, as shown under the
legend “Number of slaves.” For example, in the Voyages Database, use as a point
of departure the default map for the entire slave trade from 1514 to 1866. There
is only one yellow dot. It is placed over Africa, the continent from which all
slaves were taken. The relative sizes of the red dots show that the Caribbean,
Brazil, Mainland North America and Spanish Central America, Africa and Europe
were recipients of slaves, in that order of importance. The legend shows
approximately how many disembarked in each broad region. Rolling over the dots
gives exact statistics. Now change the time frame on the left to the period from
1808 to 1866, the era of abolition of the slave trade. You will notice that the
number of slaves represented by dots of different sizes is much smaller.
What is the
function of icons at the top of maps?
Most of the icons enable the user to
zoom in or out. As the zoom level changes, so do labels and geophysical or
At the far left are pointers to the left and right.
Once one begins to move back and forth between zoom levels by icons to the
right, these pointers provide an alternative means of changing zoom
Next, from left to right, are icons of a hand and an empty
magnifying glass. As explained on p. 20 of the Guide, these icons allow you to
zoom in a map by defining an area to enlarge: (1) click on the empty magnifying
glass icon; (2) using the cross-hair cursor, click and hold the mouse button and
then drag the mouse diagonally over the area you wish to enlarge; and (3)
release the mouse button.
The middle icons also allow you to zoom in (+)
or zoom out (-) between 4 levels or scales: 20, 6, 3, and 1, as shown at the
bottom left of the map. Scale 20 shows the largest area, but the least detail.
Only broad regions are labeled at this zoom level. Scales 6 and 3 encompass
smaller areas of the Atlantic and are suitable for maps with labels of specific
regions, but not ports within them. Scale 1 covers the smallest area and shows
the most detail. It is meant to be used for viewing maps showing the exact
location of ports and places. The bar in between the zoom in and out icons
provides another way of moving among the four scales.
Finally, the three
icons to the right allow you to set the size of the map on your screen. The
lowest setting enables you to view the map display without scrolling. In the
navigation box at the bottom right, you will see exactly how much and what part
of the entire map of the Atlantic world you can see. At the middle and high size
settings, you will have to use scroll bars to see the entire area of the map
How do I use the
positioning box in the bottom right corner of interactive maps?
of the Atlantic world shown in the map area is represented by a white rectangle
within the positioning box. Click on the zoom in magnifying glass (+) to observe
how the rectangle is reduced as one zooms in. The white rectangle stays in the
center of the box. Put the cursor on the map inside the box and move an area of
the map you wish to view under the right triangle for it to be displayed on the
To the right of
the map, “Select map” allows the user to choose between broad regions, regions,
and ports. What is the difference between these units?
The Atlantic world
is divided, for cartographical purposes, into six or nine broad regions,
depending on whether one is in Search the Database or Estimates. In the former,
the regions are Europe, Africa, Brazil, the Caribbean, Spanish Central America,
and Mainland North America. In the latter, they are also Europe, Mainland North
America, Brazil, and Africa, but further divide the remaining areas of
disembarkation into the British Caribbean, French Caribbean, Dutch Americas,
Danish West Indies, and Spanish Americas. See the answer to the FAQ about
differences between maps in the Voyage Database and Estimates for further
Each broad region contains specific regions. They are defined
differently for each broad region: nation-states in the case of Europe, segments
of the coast for Africa, large geographical areas for Brazil and Spanish Central
America, colonies in the Caribbean, and colonies / states on the North American
mainland. Specific locations, usually ports, are shown within specific
These categories are the same as those used in the “Voyage
Itinerary” category in the Voyages Database search interface
What is the
difference between “visible places” and places labeled on the maps themselves?
Visible places refers to the placement of red and yellow dots on maps. The
dots do not themselves contain labels, although rolling over them will open a
pop-up box naming the region or place the dot represents and statistics about
slaves embarked and/or disembarked there in the period indicated in the time
frame. Depending on zoom level, labels of broad regions, regions, or ports will
appear on the background map. As a rule, one should select a zoom level that
corresponds with the selection of visible places: for ports, for example, select
the finest zoom level (1).
also allows the user to choose the time period of the map. What is the nature of
choices offered here?
First, the user can choose between maps that show
only geophysical features for all periods and maps that provide as background
boundaries of states and colonies at three points in historical time: around
1650 (1501-1641), 1750 (1642-1807), and 1850 (1808-1867). The dates correspond
roughly to three eras in the history of the slave trade: Spanish and Portuguese
domination, the apogee of slave trading with the dominance of northern European
powers, and the period of its abolition and suppression.
selection of an historical map affect the display of data?
map,” choice of an historical map automatically changes the time frame to the
years appropriate to its date (1650, 1750, or 1850) and the range in the number
of slaves represented by different size dots.
represented on the map by five different sizes of yellow and red dots? How do I
interpret these symbols?
Yellow dots show places of embarkation. Red dots
show places of disembarkation. The size of dots shows relative importance, as
measured by the number of slaves affected. The larger the dot, the more slaves
were embarked or disembarked. For precise numbers, roll over the dots or center
the map on a particular place by selecting it in the drop-down menu for “Find
visible place.” A pop-up will give the exact number of embarkations and/or
disembarkations for the region or location.
How is the
number of slaves embarked and/or disembarked corresponding with different circle
A simple algorithm has been used to classify the number of
embarkations and/or disembarkations for broad regions, regions, or ports,
depending on the choice made in “Select map”, into five groups from smallest to
largest. The map program looks for the place with the smallest and largest
number of embarkations or disembarkations. The difference between the lowest
and highest number is then divided by 5, to determine the range represented by
each dot size.
interactive interface for maps on the right, how does checking or un-checking
boxes next to ranges in “Number of slaves” and “Places” of embarkation and
disembarkation affect what is displayed on maps?
Only places with a check
mark in front of them are displayed on the map. Thus, if one wants only to see
dots for the smallest of the five groups of numbers of slaves, one would remove
the check mark in front of the four larger circles. Likewise, if one is
interested only in places of disembarkation, one would uncheck the box in front
of visible places of embarkation.
What is the
function of “Refresh”?
Refresh resets the display of dots and time period
of maps according to the choices made in “Select map” and the check
How do I make
the map center on a particular place?
“Find visible place,” the tool at
the bottom of options to the right of the map, provides a drop down menu of
places, regions, or broad regions, depending on the choice made in “Select map”
above. Clicking on a place name in this list will center the map on that place,
at the second zoom level if not the first, and show statistics related to it. By
clicking on the zoom level, you will be able to see its location relative to
other places at different scales.
are shown on geophysical maps?
Within land masses, one can see rivers
(albeit unlabeled) and coastline. Within the North and South Atlantic, the most
important ocean currents are traced and labeled. The direction of currents is
clockwise in the northern hemisphere and counter-clockwise in the southern
What kinds of
detail are displayed on the historical maps?
In Europe, the area of
countries were voyages were organized are shaded. Except for Spain, labels of
the names of slave trading nations are placed off adjacent coastlines.
Africa, shaded areas show states, regions, and large population groups. The
approximate area covered by each is shown by light grey borders, and the white
labels in capital letters are the names of these territorial units. Labels in
purple are for so-called ethnic groups not associated with territorial units.
Regions of the coast, as defined by Philip Curtin and adopted on this website,
are shown in large capital letters adjacent to the coastline to which they
In the Central and South American historical maps of regions and
ports, shaded areas represent the extent of colonization around 1650, 1750 and
1850. Boundaries show political changes over the three periods The 1650
historical map for regions of the Caribbean show the small number of islands
colonized before the middle of the seventeenth century. Around 1750, close to
the apogee of the slave trade, all the larger islands are labeled at level 3 or
6 for regions; and some of the smaller islands are labeled at zoom level 1.
Finally, in Mainland North America the historical maps show areas of
colonization and the emergence of independent countries in much the same way as
for South America.
What is the
difference the main database and the estimates database?
Statistics in the
Voyages Database are for slaving voyages for which documentary evidence has been
found. Evidence of other voyages remains to be discovered. In some cases, it
will never be discovered. An attempt has been made to systematically evaluate
the completeness of the record of the slave trade for different national
carriers in different periods of time. Statistics in Estimates take into account
the incomplete nature of historical evidence and adjust figures derived from the
Voyages Database upwards to provide an account of the actual volume of the slave
What does the
command “Reset to default” do?
In Estimates, each of the boxes for setting
criteria of analysis has a “Reset to default” button. Initially, the time frame
is set to 1501-1866, the entire period of the slave trade for which estimates
are made; and flag (national carrier), embarkation regions, and disembarkation
regions are all set to include all values for each. By clicking on “Reset to
default” in a box, initial settings are restored for all specifications.
regions in Estimates and the Voyages Database defined differently?
Both sections make use of Philip Curtin’s widely used distinction of eight
regions of the Africa where slaves were embarked for transportation to the
Americas. These regions are segments of the African Atlantic coastline in Africa
from Senegambia in the North to West Central Africa in the South, with an eighth
region in South-east Africa. In the website, off-shore islands are grouped with
the region to which they are closest in proximity: the Cape Verde islands and
Madeira with Senegambia, the Banana islands and Bance island with Sierra Leone,
the Guinea islands with the Bight of Biafra, St. Helena with West Central Africa
(although slaves were only disembarked there), and Indian ocean islands, the
Mascarene islands, and Madagascar with Southeast Africa.
disembarkation regions in Estimates and the Voyages Database defined
Yes. In the Voyages Database, the Caribbean forms one broad
region, and major colonies are specific regions within it, with ports at a third
level of analysis of geographical variables. In Estimates, on the other hand,
broad regions include five wholly or partly within the Caribbean, broadly
distinguished by colonizer nations: the British and French Caribbean, the Danish
West Indies, and the Dutch and Spanish Americas. The two last had mainland as
well as island colonies. The other broad regions are the same as in Search the
database: Europe, Africa, Brazil, and Mainland North America.