Mapping South Africa by Jacana Media

Mapping South Africa will be welcomed as a landmark in providing the first survey of the fascinating story of maps and mapmaking in the subcontinent. Beginning with the Portuguese voyages of exploration in the late 15th century, the book proceeds to discuss the attempts of the Dutch and then of the British to chart and lay claim to the vast and expanding landscape of the Cape Colony. Subsequent chapters deal with maps of the Eastern Cape, where a series of frontier wars over almost a hundred years led to an outpouring of cartography. In colonial Natal and the Boer Republics of the Transvaal and Free State, cartography was driven by the dictates of colonisation and land exploitation. It was as a result of the Anglo-Boer War and of laborious trigonometrical survey work that the mapping of South Africa reached new heights and set new standards that would be extended and consolidated after Union in 1910. Throughout his book the author reveals a close appreciation of the relations between science, exploration and cartography and highlights the role played by individuals as well as institutions in producing maps of increasing accuracy and detail.

Self portrait

Andrew Duminy is a Professor Emeritus of the University of KwaZulu-Natal. His publications include a biography of Sir Percy FitzPatrick and several studies of the history of the Cape Frontier and of KwaZulu-Natal. His most recent work is a biography of his ancestor, the French mariner Francois Renier Duminy.

Mapping South Africa will long remain a standard work of its kind, admired for its informative text and for the beautiful reproductions it contains of almost a hundred maps.

9 781431 402212

ISBN 978-1-4314-0221-2 www.jacana.co.za

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To Linda

First published by Jacana Media (Pty) Ltd in 2011 10 Orange Street Sunnyside Auckland Park 2092 South Africa +2711 628 3200 www.jacana.co.za ÂŠ Andrew Duminy, 2011 All rights reserved. No part of this book may be reproduced or utilised in any form and by any means, electronic or mechanical, including photocopying, without permission in writing from the publisher. ISBN 978-1-4314-0221-2 Cover design by Abdul Amien Set in ITC Garamond Printed by Craft, Malaysia Job No. 001564 See a complete list of Jacana titles at www.jacana.co.za First published by Jacana Media (Pty) Ltd in 2011

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Contents

ONE

PREFACE

Latitude, longitude and the measurement

of time and distance Early explorers, maps and charts

The last years of Dutch rule at the Cape

The British take over the Cape

FIVE

The Great African Survey

SIX

The Eastern Cape frontier

SEVEN

Exploring the interior of southern Africa

EIGHT

Colonial Natal

The Transvaal and Orange Free State

The geodetic surveys and the arc of the 30th meridian

105

ELEVEN

The Anglo-Boer War and after

113

TWELVE

New ideas: Fourcade and Wadley

122

FURTHER READING

127

INDEX

131

TWO THREE FOUR

NINE TEN

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Preface

There are several ways of looking at maps. While collectors treasure them for their beauty, historical interest and investment value, they can also be viewed as texts, sometimes serving a hidden agenda. When made, they reflected, and often helped to create, popular interest and public opinion, and were sometimes instruments of international diplomacy. They became a matter of legal importance when nation-states demarcated their national boundaries and those of their colonies, or when there was a need to establish individual land ownership. They were needed for planning purposes when towns were laid out, roads and railways were built, and other administrative and planning decisions were made. In times of war, they were essential for drawing up military strategies and for carrying out military operations and, in times of peace, they are essential for maintaining security. In South Africa, mapping has been part and parcel of the story of conquest and colonisation. While this book touches upon these aspects, its main focus is on the quest to create accurate two-dimensional drawings of the earthâ&#x20AC;&#x2122;s surface. This required the painstaking collection of whatever information could be obtained from the observations of astronomers and surveyors. It demanded greater and greater accuracy in the measurement of time and distance and also the mounting of expeditions into regions about which no such information was available so that geodetic positions could be established and scientific surveys could take place. Early European maps were printed as woodcuts, drawn directly onto a woodblock as mirror images before the surrounding wood was carved away. By the mid-sixteenth century, the technique of copper engraving was being used and, by the beginning of the nineteenth century, the lithograph process had been developed whereby images were engraved on slate. Once printed, these maps were coloured by hand. A century later, coloured maps were being printed by lithographic methods and photo-engraving had further improved the quality of the final image.

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There are many thousands of maps and charts of southern Africa, a large number of them in manuscript form. Collectors, cartographical experts and librarians are still trying to put together a full list and are finding those of R.V. Tooley, compiled between 1952 and 1975 for the Map Collectorsâ&#x20AC;&#x2122; Circle, and that of Oscar Norwich in his Maps of Africa, previously thought to be the most comprehensive, nowhere near complete. In this book, I have based my selection less on rarity or artistic attractiveness and more on the way they reflected the development of surveying and map-drawing skills and increasing geographical knowledge. Many of them have not been published previously because only recently has highresolution digital scanning made this possible. I hope that I have succeeded in identifying the most important developments so that this book will provide a useful introduction to the history of South African cartography and will stimulate further research. I have been fortunate in being able to draw upon the writings of recent researchers, especially those associated with the project of the International Federation of Surveyors, which in 1998 launched the International Institution for the History of Surveying and Measurement. In the following year, a conference took place at Sun City in South Africa and in 2003 a groundbreaking symposium on the history of cartography was organised by the University of Cape Townâ&#x20AC;&#x2122;s Department of Land Surveying. Thereafter, at the conference of the International Cartographic Association in Durban, a working group was established to promote and encourage the study of colonial mapping between 1800 and 1950 and to concentrate upon sub-Saharan Africa during the first five years. Professor Elri Liebenberg has played a leading part in what followed and my indebtedness to her and her colleagues is obvious. I am also greatly indebted to the published works of professors Vernon Forbes, the expert on early South African travellers and cartography (and a tennis partner over fifty years ago); Laurence Adams on the history of photogrammetry; and Brian Warner on the history of astronomy. It has been necessary for me to enter such specialised fields as cartography,

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P R E FA C E

nautical navigation, astro-navigation, photogrammetry, land and marine surveying, geodesy, botany, printing, and microwave and radio technology. The possibilities for error are endless. The mistakes I have made will I hope be forgiven by experts in these fields. I also wish to thank the many institutions that have assisted me in various ways, especially in granting permission for me to use illustrations and maps from their collections. These include the South African National Library (Cape Town), the Dutch National Archive, the David Rumsey Historical Map Collection, the Afriterra Foundation, the British National Library, the British Museum, the British National Portrait Gallery, the Library of the University of Cape Town, the Campbell Collections (Durban), Hemispheres Antique Maps and Prints, Stoddard (New Haven), the William Cullen Library of the University of the Witwatersrand, the National Archives (Cape Town), the Service Historique de la Défense: Département Marine à Lorient, and the Anglo-Boer War website. Among the many individuals to whom I am indebted are Jean-Yves Le Lan, who has again provided invaluable assistance in researching the maritime records in Lorient; John Stegmann, who tracked down the Buffelsfontein Beacon (very inadequately signposted by the Port Elizabeth tourist authorities); Melanie Geustyn, who put the resources of the National Library in Cape Town at my disposal and then supervised the scanning of the maps I had selected by Craig Whyte of Artlab; and Andile Nkayi, who assisted in locating maps in the National Library’s extensive collection. My editor at Jacana, Russell Martin, provided invaluable comment as well as encouragement when it was needed. My thanks are also due to Abdul Amien, whose sharing in the interest and enthusiasm of the others involved in producing this book is evident in his inspired book design. Last but by no means least, I should like to thank the Oppenheimer Memorial Trust for their generosity in acting as a sponsor of this book.

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CHAPTER ONE

Latitude, longitude and the measurement of time and distance

The world map drawn in 1489 by Henricus Martellus, a German living in Florence, was the first to depict the southernmost tip of the African continent after it had been rounded by Bartolomeu Dias. Although Dias had established the latitude of his landing as 34° 22' S, Martellus extended the African continent to 45° S and also the continent of Asia southwards in a solid landmass. It is believed that he did so on the basis of false information given by Columbus’s brother in order to exaggerate the difficulty of sailing to the East by this route. (British Museum)

After the creation of Pangaea, continental drift caused the continents to tear apart, creating jagged landmasses that narrow as they stretch southwards. South America narrows to become Cape Horn, Africa stretches southwards to Cape Agulhas, while Asia breaks up into the untidy collection of archipelagos and islands of Indonesia before the southernmost tip of Australia is reached at South East Cape and that of New Zealand at South West Cape. These obstacles have to be negotiated by ocean-going traffic sailing between the southern oceans. While the rounding of the southern tip of Africa does not require sailing in the icy Antarctic latitudes, the Cape of Storms is formidable nevertheless, for huge waves thunder

towards it, swelling from the southern Atlantic, driven towards the shore at certain times of the year by gale-force winds. When the north-flowing Antarctic current clashes with the southerly Mozambique current, this can cause mountainous seas that still send ships to a tragic end. Over two thousand ships have come to grief on these treacherous coasts, most of them during the age of sail before the compilation of accurate charts and the scientific developments described in this book made it safer for the attempt to be made. The Portuguese exploration of the west coast of Africa, which culminated in Bartolomeu Dias’s circumnavigation in 1488, was surely one of the most challenging events in the history of seafaring. It outranks Columbus’s discovery of America in at least two respects. The first is that Columbus’s voyage in 1492 did not require the succession of expeditions that involved the gradual exploration by Portugal of the unknown coastline of Africa. As important, Columbus was able to take advantage of the easterly wind that was known to blow towards the Americas north of the equator. But the Portuguese ventured southwards, sometimes into headwinds, across the equator and into southern latitudes where the weather patterns were unknown. Some of the beautifully coloured charts that were drawn and used by the Portuguese mariners who inched their way southwards were published in 1960 to commemorate the five-hundredth anniversary of the death of Prince Henry the Navigator. They provide a vivid reminder of these brave and world-shattering journeys. One of the major challenges in the exploration of both America and the west coast of Africa was the uncertainty of making the return journey when little or nothing was

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Fra Mauro’s world map, commissioned by the King of Portugal and drawn in 1459, before Columbus’s ‘discovery’ of America or Dias’s circumnavigation of the Cape, provides a remarkably informed picture of the continents of Europe, Asia and Africa. It was orientated with South at the top, according to the Arabian and Chinese practice, which was soon abandoned by European cartographers. (Wikimedia Commons)

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This map (opposite) showing the west coast of Africa was included by the Dutch cartgographer Johannes van Loon in his Sea Charts, published in 1661. (Hemisphere Antique Maps and Prints) This map of the southern African coastline, produced in Germany in 1513 by Martin Waldseemüller, was the first printed map of southern Africa. It shows numerous inlets as they had been viewed from out at sea by Dias and other Portuguese explorers; most of them were assumed to be river mouths. Waldseemüller is believed to have used information obtained from Arabian sources in drawing the east coast of Africa, extending places shown on them further southwards. The island of Madagascar is completely out of position. Apart from vaguely defining the shape of the African continent, the map would have been of no value for navigational purposes. (Hemispheres Antique Maps & Prints)

known about the trade winds. Again, Columbus was able to draw upon knowledge that had been accumulated over the centuries by seafarers in the Baltic and North seas and so was able to reckon on encountering westerlies at higher latitudes. Although it is now recognised that the Portuguese drew on information available to Arabian and Chinese mariners, they could not be certain that the wind would blow from the opposite direction at other times of the year. This was doubtless one of the reasons why Dias’s crew threatened mutiny as he continued to venture eastwards and why he therefore made the decision to turn back at a point off the Transkei coast and returned to Portugal, sailing west along the Cape coast and then north-west along the west coast of Africa. It must have been after his return to Portugal that Henry the Navigator’s team of experts, on examining the record of Dias’s voyage, first realised that the wind patterns of the southern hemisphere are basically a mirror image of those in the northern hemisphere. They must also have realised that, in the same way as ocean currents sweep northwards

along the eastern coastlines in the northern hemisphere, they sweep southwards in the southern hemisphere. Once these discoveries had been made, the sailing routes from Western Europe to the East were soon established. Vessels leaving Europe would sail between December and April when north-easterly winds prevailed, heading for the Canary Islands. Tenerife, the largest island in the group, was fairly easily spotted because of the height of the extinct volcano that stands on it. From there, ships bound for the West Indies and North America would sail towards the west, making use of the easterly winds that blow across the Atlantic at that latitude. Those travelling to India would veer in a south-westerly direction towards the coast of South America, relying upon the southerly current to carry them across the equator when the winds became erratic or dropped altogether. As they sailed southwards, they began to pick up the westerly winds which strengthened as they proceeded, well to the south of the African continent. These winds could be relied upon to take them into the Indian Ocean, whether the final destination was India, Ceylon (Sri Lanka), Java and the Spice Islands, or China. Ships calling at Cape Town soon learnt that the safest approach was from the open sea to the south-west, using the south-easterly winds before the shelter of Table Mountain was reached. The onward journey to the East required that the ship proceed southwards to latitude 35° S, after which a course was set eastward, taking care to avoid the dangerous Agulhas Bank, compensating for a compass variation of over 23° at this position. In the Indian Ocean itself, European navigators were able to draw on the knowledge of Chinese, Arabian and Indian navigators who had for centuries been sailing to and from China, Indonesia, India, Arabia and Africa. The route northwards through the Mozambique Channel between the east coast of Africa and Madagascar was not favoured because of the contrary current, the unreliable cyclonic winds that occur between December and March, and the numerous coral shoals that had to be avoided. More straightforward was the return journey to Europe for ships with goods loaded up to the gunwales in the East. To make the best

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use of the monsoon winds and to avoid an area known for its hurricanes, ships sailing from India favoured a circuitous route well to the east of the French island of Mauritius (then known as Île-de-France). Thereafter, the wind veers towards the east and then becomes a south-easter around the Cape. Cape Town therefore became a regular port of call before the journey continued up the west coast of Africa. After leaving Table Bay, shipping stayed close to the African coast, as Dias had done, taking advantage of the northerly Benguela current, with St Helena or Ascension Island providing a last stop-over before the journey continued past the Azores towards Europe. If the winds were favourable and if no mishap occurred, the outward journey to India and back took eight or nine months in either direction, so that the total voyage took between eighteen and twenty-two months, allowing for the time spent bartering and loading goods in India or Indonesia. Because during the sixteenth and seventeenth centuries the southern coast of Africa was avoided by most ships sailing to the East, charts used for navigation did little more than provide directions for sailing around it, with scant information about the coastline except for Table Bay. Rhumb lines, indicating wind directions, showed the direction in which the ship should set its course by means of a compass, which provided an indication of north when this could not be obtained from observing the unfamiliar southern skies. Though navigators had a vague idea of how many days’ sailing would be needed, it was impossible to measure these distances with any accuracy. A knotted line cast overboard with a wooden chip tied to it could give some indication of speed as the knots were counted during a given period, but it could give no indication of the speed of the current, which would also affect the distance that the ship travelled. Otherwise, experienced seamen estimated the speed of the ship by looking at the height of the bow wave and by

Frederik de Wit’s chart of the western Indian Ocean (1675) provided rudimentary instructions on how to reach the west coast of India by sailing around the Cape. De Wit had been apprenticed to the famous Dutch cartographer Willem Blaeu and went on to found his own publishing house in Amsterdam, producing maps and charts of fine workmanship and precision. His Zeekarten were the most reliable charts to have been produced in their day. (Hemispheres Antique Maps & Prints)

listening to the sound of the wake. They also found clues in the height and shape of the swells in the sea, the appearance of clouds on the horizon, the smell of the air, the presence of smoke, and the observation of birds, turtles and seals. Early navigation thus depended to a very large degree on instinct and experience. In 1610 the English mathematician and astronomer Edward Wright published a book, Certaine Errors in Navigation, Arising either of the Ordinarie Erroneous Making or Using of the Sea Chart, Compasse, Crosse Staffe, and Tables of Declination of the Sunne, and Fixed Starres Detected and

This nineteenth-century illustration shows how a chip-log was used to estimate a ship’s speed.

Corrected, in which he showed that, despite the progress that had been made during the previous century, many questions remained unanswered as far as navigation was concerned. Even skilled navigators taking the utmost care could miss their targets by as much as 500 nautical miles on a voyage to the West Indies. He advocated improved charts that used the Mercator grid system and offered practical advice on how to compensate for magnetic variation. He also showed how readings taken by means of the cross-staff, a simple device made of wood that enabled the height of the sun to be measured at midday, could be improved by making allowance for parallax as well as for the height at which they were taken

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Though D’Alembert’s illustration of the marine compass in Diderot’s famous Encyclopédie shows a very crude instrument, it must have been a fairly accurate representation of the instruments then in general use. The liquid marine compass, which stabilised the movement of the needle, was not invented until 1813 and a system of gimbals followed, so enabling the compass to remain level regardless of the motion of the ship when permanently fixed on the navigation deck.

from the deck of a ship. Wright could offer no advice on how longitude could be established with greater accuracy. In his words, there was an ‘inextricable labyrinth of error’. This situation was little altered until the mid-eighteenth century. Latitude could be established with reasonable accuracy by means of the cross-staff, while the back-staff invented in 1594 made it possible to do this by measuring the sun’s shadow instead of looking directly into the sun. The establishment of longitude was, however, a different matter. In 1530 the great mathematician Gemma Frisius, in his book De uso globe, explained that it was necessary to invent a clock that kept time accurately after it had been set at the place of departure. Longitude could then be established, provided that the observer had with him an almanac showing the time of a natural occurrence such as the azimuth (the moment at which the sun reaches its highest point) or an eclipse at the point of departure. An extremely accurate reading would be necessary, for a difference of one minute would result in an error of 2½ degrees of longitude, while one second translates into an error of 20 kilometres at the equator. Such errors could mean disaster for a ship placing its reliance upon a chart when approaching shore. During the seventeenth century a number of developments took place that gave rise to the expectation that the surface of the earth could be accurately measured and mapped. The first was the invention of more accurate clocks. ‘Time’ is an abstraction based on the notion that there exists in the universe a regular period that can be measured by means of dividing the days of the year into hours, minutes and seconds. The first pendulum clocks were built in the midseventeenth century and were soon refined, reducing friction in their moving mechanical parts and minimising the effect of air resistance on the pendulum. In optimum conditions, they began to achieve a variance of only 10 seconds or less in a day. The invention of the pendulum clock was quickly followed by the invention in the 1670s of a clock that was regulated by a fine coiled spring (the invention was claimed by both Robert Hooke, the English inventor, and Christiaan Huygens, the Dutch inventor of the pendulum clock). The second development of importance was the

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construction of more powerful telescopes. The manufacture of lenses is a slow and intricate business, but by 1610 Galileo had succeeded in making a telescope that could enlarge an image twenty times and, within a decade, Johannes Kepler developed a telescope with a larger field of view using two convex lenses. With his telescope (or perspicullum as he called it) Galileo was able to observe the waxing and waning of the planet Uranus as it orbits the sun and to discover Jupiter’s moons. The first helped to confirm Copernicus’s theory that the planets revolve around the earth. The second opened possibilities for the measurement of time by means of observing the regular orbiting of Jupiter’s moons and this could therefore be used to establish longitude. The third development of importance was the invention in 1647 of logarithms after the mathematician John Napier had grappled for twenty years with the idea of using the integers of numbers to simplify complicated arithmetic calculations involving multiplication or division. The impact of logarithms in the seventeenth century was as great as that of computers in modern times. Not only did they speed up the calculations that were necessary in the ‘measuring sciences’ such as astronomy and surveying, but they eliminated many errors and made even more complex calculations possible. Most important, they gave birth to the mathematics of trigonometry (first proposed by Gemma Frisius) by means of which it is possible to fix the third point of a triangle and to calculate the length of its three sides if the length of one side of the triangle (the baseline) and two of its angles are known. Alternatively, it is possible to do this if the length of two sides and the angle between them are known. On 26 June 1674 English and French astronomers co-operated in observing a total eclipse of the moon at Greenwich and Paris, so enabling them to calculate the relative longitude of the two positions. This was followed during the last quarter of the seventeenth century by several attempts at establishing the position of other places on the earth’s surface relative to Greenwich or Paris. Heavy and bulky telescopes and pendulum clocks had to be transferred to these sites, the first of them being Jamaica, where the eclipse of 26 June 1674 was observed and a record of

observations sent to Greenwich. The Paris Observatory organised similar expeditions to observe lunar eclipses as well as the transit of the moons of Jupiter from positions in French Canada, Cayenne in French Guiana, Avignon and Gda sk. In 1676 the famous English astronomer Edmund Halley (after whom Halley’s comet is named), co-operating with the French, sailed for the island of St Helena to make observations there, as well as to map the stars of the southern hemisphere. In some ways, the outcome of these endeavours was disappointing, not least because clouds often prevented crucial observations from being made and because it was discovered that pendulum clocks lose time at lower latitudes. (It was not until 1687 that Sir Isaac Newton explained that this was due to the fact that the earth is not a perfect sphere, as was previously believed, so that pendulums are affected by changes in gravitational forces.) Nevertheless, work proceeded on the time-consuming collection and correction of astronomical data. In France, the great Italian astronomer Giovanni Cassini, who in 1669 had been enticed by Louis XIV to head the Paris Observatory, discovered a means of establishing longitude by observing Jupiter’s moons through three huge telescopes, assisted by pendulum clocks, one beating every second and the other every half-second. This gave rise to the possibility that an accurate map could be produced of France and he was ordered to do so by the French king. The basic scale was determined by first calculating the circumference of the earth by measuring a section of the Paris meridian from Paris to Amiens, starting with a baseline between Paris and Fontainebleau. Major positions were then fixed according to astronomical observations of Jupiter’s moons and other positions were then located by means of triangulation. Though a preliminary map of the French coastline was produced in 1693, it took nearly a century before the final map was completed in 1789. Drawn

Cassini’s planisphere was an achievement that well demonstrates the many advances made in astronomy, mathematics and surveying by the end of the seventeenth century. It was laid out on the floor of the Paris Observatory and showed the world viewed from the North Pole, with lines of latitude continuing to radiate beyond the equator. A pointer was attached to the North Pole by a cord and it could be set to any latitude and then rotated until it reached the longitude of any place shown on the map. The Paris meridian, on which the Paris Observatory was located in 1667, was thought to be exactly 20 degrees east of the Île de Fer (today known as the island of El Hierro) in the Canary Islands, which had previously been used because of the coincidence of magnetic and true north at that position. It was not until 1884 that international agreement was reached to recognise Greenwich as the prime meridian. (Bibliotheque Nationale)

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Borda’s repeating circle, invented in 1784, greatly improved the accuracy of survey readings. The angle being measured was repeated a number of times by means of rotating the circle, after which the reading was averaged.

on multiple sheets employing standard symbols, it measured over 100 square metres when its sheets were laid side-to-side. Owing to the difficulty of transporting the large instruments that were required, it was almost impossible to achieve in other parts of the world the accuracy of the astronomical observations that were made in the late eighteenth century at the Paris and Greenwich observatories. They were altogether impossible from a ship at sea because the movement of a ship’s deck disturbed telescopic sightings as well as the movement of pendulum clocks. Spectacular as the inventions of the seventeenth century were, they did not therefore produce significant improvements in the drawing of maritime charts, and mariners continued to navigate as best they could, establishing their longitudinal position largely by means of guesswork. The invention that altered all this was the sextant. This device employs a small telescope that focuses through paired mirrors, one of which is fixed while the other is attached to a moving plate. When two objects, such as the rim of the sun and the horizon, are viewed, the images are lined up by means of adjusting the moving mirror. This movement is then measured as an angle on a scale at the bottom of the instrument. Like the theodolite, the sextant measures angles, but the two objects being observed do not have to be in a horizontal or vertical plane and, as they are viewed simultaneously, the pitching and rolling of a ship is minimised. The principle was first used by John Nicolas Bellin was one of the leading cartographers of the eighteenth century. He was for many years head of the French government’s cartographical department, the Dépôt des Cartes et Plans de la Marine, established in 1720, and produced hundreds of charts of all parts of the world that were widely used by French mariners. This chart, showing the southern and eastern coasts of Africa, was produced in 1740. It has many errors due to the absence of accurate longitudinal positions east of the Île de Fer.

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Hadley when in 1731 he invented an instrument he called a ‘quadrant’ because it could measure angles up to 90 degrees. The sextant, manufactured for the first time in 1757, measured angles of up to 120 degrees. The sextant had two consequences of crucial importance for navigation and charting. The first was that it made possible the calculation of longitude by means of measuring the distance between a fixed star and the rim of the moon, or between a star and one of the planets, as an angle (these measurements were known as ‘lunar distances’). Navigators had to take at least three readings and to repeat them as often as was possible in order to minimise error. The first was of the moon above the horizon. The second was the altitude of the chosen star. The third was the distance between this star and the moon. These observations then had to be ‘corrected’ to allow for parallax and refraction. After these observations had been made, it was necessary to consult published tables that provided details of the time at which these readings were obtained at Greenwich or Paris. The difference in time then provided the longitude of the position of the observer, time being established by means of a spring-balance clock that had been set at noon or, less accurately, by an hourglass. By the 1760s, both in England and France, further tables were available that made it possible to determine time by means of stellar observations (most commonly the moons of Venus). These calculations took even experienced navigators about four hours to complete but, if properly carried out, they could be accurate to within half a degree of the arc. Apart from making charts more reliable by means of the more accurate determination of both latitude and longitude, the development of the sextant and the availability of more powerful telescopes made it possible to chart coastlines more accurately. Before a survey could begin, the latitude

The quadrant, pictured here, soon evolved into the sextant by means of the attachment of a small telescope and the extension of the measuring arc to 60 degrees, so enabling it to measure angles of up to 120 degrees.

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D’Alembert drew this illustration for Diderot’s famous Encyclopédie, published between 1751 and 1772, to illustrate how the survey of a bay was carried out from an offshore position.

and longitude of a chosen position had to be established. If a telescope could be brought ashore, the readings were taken on land. Thereafter, in ideal conditions, a baseline was measured and marked so that it would be visible from the sea. Bearings were then taken from other points along the shore or offshore from the survey ship or a small rowing boat called a pinnace. A sextant held horizontally was used to measure these angles when it was not possible to do so by means of a theodolite or a plane table. To estimate the distance of a point on land from out at sea, it was necessary first to calculate the distance between the two offshore positions from which observations were being made. When rough seas made such surveys impossible, the coastline would be surveyed from a moving ship, with the main landmarks being recorded as best possible. These were known as ‘running surveys’ and very often resulted in no more than a sketch of the coastline as seen from the sea. It was often impossible to tell, as the ship sailed along the coastline, whether a gap between two headlands was a river, a strait leading to open water beyond, or a flat coastal plain, although the presence of fresh water or an offshore current sometimes provided clues. If the sky was clear, astronomical observations would be carried out at sunrise, noon and sunset to fix the position of the ship at these times and to check the accuracy of the distances run. Survey work was slow and tedious and required a high degree of seamanship, for it could also be extremely hazardous. When approaching an unknown shore, once sails had been shortened, it was necessary to keep a constant lookout for submerged rocks and shoals. A trained seaman would have to stand near the prow to take readings of the depth of the water by means of casting the lead weight of a plumb-line ahead of the ship. These readings were called out to the ship’s pilot and, if they were also necessary for the

compilation of a chart, had to be recorded, together with an estimate of the ship’s speed and the time that elapsed between the soundings. Other members of the crew stood by, ready to drop anchor at a moment’s notice should the wind rise unexpectedly, should a submerged obstacle be sighted or should the depth of the sea suddenly diminish. A seaman’s worst nightmare was to be driven uncontrollably towards a shore to leeward, and for this reason ships engaged in survey work carried at least three anchors and were usually light vessels, such as one-masted sloops, that could be more easily manoeuvred. Once the actual survey had been completed and the numerous calculations made, draughtsmanship and a considerable degree of artistry were required in drawing the final charts. In view of the special qualities that were required, few qualified seamen chose to do survey work. In the merchant marine, it was more profitable to trade in distant ports and to transport goods across the ocean. In wartime, naval surveys became a priority but, until the early nineteenth century, when the British government itself took on the production of Admiralty charts, survey work was seldom undertaken by the Royal Navy itself. Most surveys were therefore carried out by dedicated expeditions, financed in the interests of scientific research or because they held the prospect of national prestige or rewards in the spice, plant, fur or slave trades. By the end of the eighteenth century, another instrument had begun to revolutionise navigation and charting. This was the chronometer. Both the British and French governments had offered substantial rewards for a solution to the problem of establishing longitude at sea, for it had become obvious that the nation that solved this problem first would command the oceans and, with it, the trade of the world. Responding to the reward offered by the Board of Longitude, the English clockmaker John Harrison spent many years developing ways of overcoming friction and expansion on the mechanical parts of a clock and produced no less than five prototypes. The third of these (H-3 as it is known) took 19 years to reach its trial stage in 1760. It had 753 parts, most of them moving, and was about 2 feet high. H-4, completed at about the same time as H-3, was to win the British longitude prize. Five inches in

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Apart from surveying False Bay in 1780, Captain Joseph Huddart (also spelt Huddard) spent many years surveying the coast of India for the East India Company and is also famous for his surveys of the coast of Scotland.

diameter and weighing only 1.5 kilograms, it had to be wound daily but, unlike other clocks, could be rewound without this affecting its timekeeping. H-4 was tried at sea on voyages to Jamaica in 1761 and 1762 and again on a voyage to Barbados in 1764. On the first voyage, it lost only two minutes. In view of the growing reliance upon chronometers that followed Harrison’s invention and the effect this had on navigation and the drawing of charts, it is important to realise that the switch-over was not immediate. Lunar distances were still needed when chronometers stopped or lost time, either because of malfunction or because they had not been rewound. Chronometers had also to be regularly serviced and reset and, even when properly handled and maintained, could not be completely relied upon. While ships were in harbour, within sight of an observatory, ‘timeballs’ were dropped at noon to enable them to check their Huddart surveyed False Bay between Simon’s Town and Cape Point (‘Seamon’s Bay’) in 1780 after the Colebrook had been wrecked in 1778 after striking Anvil Rock, just to the south-east of Cape Point. He failed to locate the rock, which is about four metres beneath the surface. The pinnace from which he took observations was itself overwhelmed by a wave during the survey. (National Library)

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chronometers. In Cape Town, from about 1806 a gun was fired at noon from the Imhoff Battery adjacent to the Castle. (In 1902 the gun was moved to the Lion Battery in order to cause less inconvenience to the local inhabitants.) It was not until the invention of shortwave radio that it became possible for ships at sea to check their clocks against Greenwich time by means of the pips that were sounded before news broadcasts. During the nineteenth century, ships would therefore commonly carry three chronometers so that they could be checked against each other, and whenever ships passed at sea, they would consult in order to ‘check their clocks’. Survey ships could carry as many as forty of them. When it became possible for ships at sea to establish longitude with a reasonable degree of accuracy, charts used for navigational purposes began to abandon the rhumb lines which had previously provided directional guidance using compass and wind directions. It also became necessary for

charts to indicate the position of the prime meridian from which degrees of longitude were shown, either to the east or to the west of it. Ever since the early days of Spanish and Portuguese exploration, the island of Tenerife had been regarded as the prime meridian, having been used by Ptolemy as the western limit of the world as it was known in the second century AD. English charts now began to use Greenwich, and French ships to use the Paris meridian, although the Île de Fer (El Hierro island) in the Canaries was for a time used because magnetic and true north seemed to coincide at this position. The Dutch generally used Tenerife or the Amsterdam meridian, although their charts of the Cape coastline usually showed degrees of longitude east of Cape Town once the longitude of this position had been established by the 1750s. It was not until 1884 that international agreement was reached to recognise Greenwich as the prime meridian.

Although Portuguese explorers, including Perestrello, had obtained fairly accurate latitudinal readings of positions along the southern African coastline, most early maps show Cape Point as the southernmost point of the continent, with the coast receding in a north-easterly direction from there towards Delagoa Bay and with Algoa Bay at a lower latitude than Table Bay (though they have almost the same latitudes). The width of the continent is also imprecise, and was usually narrowed, because no accurate longitudinal positions could be established. The size of inlets (some imaginary) varies from map to map. These four maps provide examples of these distortions. Abraham Ortelius’s map of Africa (top left), published in Antwerp in 1570, was included in an atlas that attempted to show accurate details of the four continents, using information available in Spanish as well as Portuguese naval records. That of Justus Danckerts (top right) was published in Amsterdam in about 1680 and is very similar to those produced at the time by other Dutch cartographers, including Frederik de Wit. Guillaume Delisle (bottom left) was a pupil of Giovanni Cassini, the director of the Paris Observatory, and in 1718 became the geographer of the French King, in which position he was able to access information from French astronomical and naval sources. He produced about 60 maps, all of which were meticulously researched and drawn. Though they show the African continent narrowed because of miscalculations of longitude, they were nevertheless for many years regarded as authoritative. This is shown by the map drawn in 1787 by the British cartographer Thomas Bowen (bottom right), based on ‘the best authorities’ but produced many years after more reliable information had become available from French sources. (National Library)

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Self portrait

Mapping South Africa will long remain a standard work of its kind, admired for its informative text and for the beautiful reproductions it contains of almost a hundred maps.

9 781431 402212

ISBN 978-1-4314-0221-2 www.jacana.co.za

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