The British Contribution to Cartography in the Eighteenth Century: Instruments, Surveys and Global Mapping

Introduction and scope

A detailed study of the British contribution to cartography before the eighteenth century lies outside the scope of this outline.

Accounts of the achievements of men such as George Lily, Christopher Saxton, Norden, Speed, Ogilvy and John Adams, to mention a few names only, can be found in the works of Sir George Fordham, Dr. Edward Lynam, and Prof. E. G. R. Taylor.

In the second place, the emphasis here must be on the general development of maps and mapping, and it cannot be claimed that, however important in British cartography these sixteenth- and seventeenth-century cartographers are, they were in the van of technical progress. In the main they followed, often with a considerable time lag, the practice of their contemporaries in Portugal, Italy, the Low Countries and France.

Saxton is surmised to have used methods of survey developed by Gemma Phrysius, and much of the attractiveness of his county maps is due to his Flemish engravers.

The maps of Sanson and Delisle were industriously copied by English map publishers like William Berry, and the surveyors who in the eighteenth century won with their county maps the prizes offered by the Royal Society of Arts were not superior to the men who were producing the Cassini map in France.

Notable exceptions and early advances

There were of course exceptions to this generalization.

The magnificent Molyneux globe of 1592, the first made in England and by an Englishman, was not excelled by any contemporary production.

An important contribution to map projections was made by Edward Wright when he worked out mathematically the formula for Mercator’s projection.

The exiled Sir Robert Dudley was the first to employ this projection generally for the charts in his lavishly produced ‘Arcano del Mare’ (Florence, 1646).

Nor must we overlook the stimulus which the epoch-making work of Newton exerted through astronomy and geodesy upon the development of cartography.

Nevertheless, by and large, British map-making until the late eighteenth century was definitely behind that of other nations.

Perhaps the best of a poor field in the first decades was Herman Moll, a Dutchman who came to London some time before 1682. His numerous maps are rather poorly designed and crudely engraved, but he made some effort to keep abreast of continental advances.

State of British cartography c. 1738

In 1738, John Green was lamenting the poor state into which the science had lapsed: he pointed out that cartography had fallen entirely into the hands of engravers, who copied each other without discrimination.

Those “ignorant or mercenary Hands” who happened to become possessed of original material jealously concealed it from their rivals.

To such conduct he attributed “‘the little Esteem, or rather great Contempt, that Maps are in here’’. He himself made some effort to remedy this state of affairs, in part as an employee of Thomas Jeffreys, but the first important British contribution was made through the development of instrumental equipment, which was effective in improving first the hydrographic charts, and then the maps.

Mathematical and instrumental advances

In the eighteenth century the fundamental advances in mathematics and astronomy initiated by Sir Isaac Newton gradually bore fruit.

The motions of the heavenly bodies were marked out, so that they could be accurately predicted for long periods, and eventually published annually in the ‘Nautical Almanac’ from about 1767.

With the aid of lunar tables, the method of determining longitude within one degree by lunar distances was perfected.

To this accuracy, the advances in the design of instruments also contributed; John Hadley had improved the quadrant by the introduction of reflecting mirrors, and more accurate readings were obtained from the use of the vernier scale.

Meanwhile, John Harrison was engaged in designing and constructing a time piece which would be sufficiently robust and accurate to allow longitude to be determined from the difference between local time and the time indicated by the chronometer for a given meridian.

The method had earlier been described by Sir Isaac Newton.

Chronometers and navigation

Harrison was eventually awarded the prize offered by Parliament to “such person or persons as shall discover the Longitude” in 1772, and a copy of his successful chronometer was used by Capt. Cook on his second and third voyages, giving extremely accurate results.

This method by ‘transport of chronometers’ finally superseded that by lunar distances.

Though these instruments were initially used in navigation and hydrographic survey, it must be remembered that the explorers of the following century relied largely upon the sextant (an improvement on the quadrant) and the chronometer for the surveys they were able to accomplish.

Theodolite and Ramsden’s graduating engine

Another survey instrument which at this time emerged in its essentials was the theodolite, a descendant of the ‘polymetrum’ devised in the early sixteenth century.

By the invention in 1763 of his graduating engine, Jesse Ramsden solved the problem of dividing the brass circle accurately, and then worked on his famous theodolite for a number of years.

This included a horizontal circle three feet in diameter, which by the aid of micrometers enabled readings to single seconds to be obtained.

The sighting vane of the older models was replaced by a telescope moving freely in the vertical plane of the instrument.

This theodolite was admittedly heavy and cumbrous, but it proved the most efficient instrument for observing angles in survey, and by gradual modifications it has developed into the highly precise and portable patterns of today.

This instrument was first employed in the connexion by triangulation of England and France in 1787, and later in the Ordnance Survey of Britain and in India.

Impact on hydrography and mapping

The first results of these technical advances were seen in the increased accuracy of hydrographic charts, and in their production and publication Great Britain assumed the lead which she has maintained for the last 150 years.

The end of the eighteenth century may be approximately taken as the point at which the general outline of the continents, outside the Polar circles, and their precise position had finally been determined, though much patient and careful work had still to be carried out before all the details were filled in.

In the remainder of this outline, therefore, we shall no longer be concerned with the seaman’s contribution to the ‘unrolling of the map’, but must leave it with a brief tribute to the work of Cook, Vancouver, Flinders and their colleagues in Pacific, Australian and Antarctic waters, and to their successors, Fitzroy, W. F. Owen, P. P. King, Moresby, Nares and other distinguished navigators. Upon the work of these men are founded the charts issued by the Hydrographic Department of the Admiralty.

Two extra-European fields: North America and India

Two extra-European fields for cartographic work were open to British surveyors in the eighteenth century, North America and the Indian sub-continent, and in both they acquitted themselves creditably, not only paving the way for subsequent advances, but providing the first adequate maps of those areas.

For North America, apart from the coasts and the immediate hinterland in the east, only maps based on the rough sketches and reports of explorers were available before the middle of the century.

One contemporary cartographer it was candid enough to admit that beyond the Great Lakes, the detail was ‘in great measure guess work’.

The progress of settlement, the organization of the colonies, and particularly Anglo-French rivalry, created a demand for general maps of greater reliability, and led land surveyors to turn from their work on estates and plantations and to apply themselves to the wider problem. In the early years, considerable encouragement was given by the Lord Commissioners for Trade and Plantations.

Lewis Evans and colonial mapping

Two notable general maps incorporate the results of this activity. In 1749, Lewis Evans published his ‘Map of Pensilvania, New-Jersey, New-York’, etc., on the scale of 15 miles to 1 inch, based on numerous determinations of latitude, and two longitudes, those of Philadelphia and Boston.

To these, he had fitted the ‘Draughts and Discoveries’, with which many gentlemen had furnished him.

That the map was based in great part on route surveys by distance and bearing is shown by his remark “‘No distance could be taken but by actual Mensuration (the Woods being yet so thick)’, i.e. the surveyors were unable to triangulate with the circum-venter or early theodolite.

Six years later, the map was issued with additions, as the well-known ‘General map of the Middle British Colonies, in America’. This map was at once in great demand, and was much used in North America during the Seven Years’ War.

When he issued a further extended version of the map in 1776, Governor Thomas Pownall, himself something of a surveyor, could say, ‘‘Where local Precision has been necessary this Map has been referred to not simply in private but public Transactions, such as the Great Indian Purchase and Cession’’.

John Mitchell’s map and its role

Governor Pownall was also associated with another and more famous map of this period; John Mitchell’s ‘Map of the British and French Dominions in North America’, published by Thomas Jeffreys in 1755. Mitchell was a botanist who had settled in Virginia early in the century, returning to England in 1747.

Little is known of his cartographical work, and his map probably owes something to Jeffreys. It represents eastern North America from the southern shores of Hudson Bay to the Mississippi delta, on the scale of approx. forty-three miles to the inch.

A prominent feature is the detailed statement of the authorities followed in its compilation. It is stated that the map was undertaken “with the Approbation and at the request of the Lords Commissioners for Trade and Plantations and is chiefly composed from Draughts, Charts and Actual Surveys… great part of which have been lately taken by their Lordships’ Orders”.

With this official character, it is not surprising that the map played an important part in the peace negotiations between the American colonies and Britain in 1782, for on it the boundary between Canada and the United States was laid down.

Surveying India: Rennell and the Bengal surveys

The second great field for British cartography was in India. Before the time of D’Anville there was nothing approaching an accurate map of the sub-continent, and large areas of the interior were blank.

From about 1750 onwards, the East India Company, to forward their commercial expansion, actively promoted the charting of the coasts, and this work was later stimulated by their hydrographer, Alexander Dalrymple.

The first systematic land surveys resulted from the activities of Major James Rennell in the Bengal Presidency, the first extensive area to fall under the Company’s complete control.

In his twelve years in India (from 1767 to 1777 — he was the first Surveyor-General of Bengal) Rennell initiated and directed a comprehensive and uniform survey of Bengal and Bihar, to meet military, administrative and commercial demands.

The survey was based upon a network of distance and bearing traverses, controlled as the work progressed by cross bearings and closed circuits.

A further control was afforded by observations for latitudes. Distances on large-scale work were measured by chaining, in other cases by perambulator.

Quadrants were employed for horizontal angular measurements as well as for obtaining latitudes, and theodolites were gradually introduced.

Much of the work was based on traverses along the rivers and main roads, details of the countryside being largely filled in by estimation.

Given the methods employed and the difficulties encountered—Rennell himself was severely wounded and suffered constant attacks of fever— the results were extremely creditable, and the standard of mapping was much higher than that of many European countries.

Rennell’s publications and legacy

The first edition of the ‘Bengal Atlas’, with maps on a scale of 5 miles to 1 inch, was published in London in 1779, two years after Rennell’s return on pension.

In London, he continued to maintain his interest in the mapping of India, and in 1782 published his great ‘Map of Hindoustan’ with a ‘Memoir’.

This map, in four sheets on the scale of one equatorial degree to one inch, was a remarkable piece of compilation.

The sources used are critically discussed in the ‘Memoir’; they included the East India Company charts communicated by Dalrymple and route surveys by military engineers accompanying military expeditions, adjusted to an astronomical framework of latitudes and longitudes, the latter mainly for coastal cities obtained from the eclipses of Jupiter’s satellites.

For the Punjab he relied largely upon a map done by a native, giving the courses and names of the five rivers, ‘which we have never had before’.

With the advance of British arms, Rennell was continually receiving fresh material, and six years later he published a revised and enlarged edition (14 in. to 1 degree), and this was followed by further editions in 1792 and 1793.

Knowledge was now increasing so rapidly that it became impossible to compile a map of the whole country on the methods employed by Rennell; however, until the emergence of an organized Survey department and the completion of the Great Trigonometrical Survey in the next century, Rennell’s ‘Hindoustan’ remained the basis of Indian cartography.

Map publishing in London

All this activity on land and sea was making available a great mass of cartographic material to the map publishing houses in London.

It was through the output of these firms, in which the new facts were collated and presented in convenient format, that the work of surveyors all over the world ultimately reached the public.

No longer did this filter at second hand through the publications of continental establishments. London had become the universal centre of cartographic progress.

During the period of the revolutionary and Napoleonic wars, the seas were the virtual preserve of British sailors, and maritime, commercial and military enterprises, while requiring the best available maps and charts for their execution, provided in return a mass of observations and records by which the existing material could constantly be amended.

British cartographers availed themselves to the full of these opportunities, and for the first time their work received international recognition.

Parallel with this expansion, there was a marked improvement in the construction and engraving of their maps, which, by their clarity and freedom from conjectures or unverified detail, in themselves conveyed a general impression of accuracy and thoroughness. British cartography was thus freed from its dependence upon continental sources.

Thomas Jeffreys, Faden, Cary

The beginning of this advance is to be found in the work of Thomas Jeffreys.

He was the publisher of Benjamin Donn’s one inch to the mile map of Devonshire, the first county map to win the award of £100 offered by the Royal Society of Arts, 1765, and himself surveyed several counties.

His most important later work was the publication of the improved charts of the American coasts resulting from the labours of men like James Cook. Important collections of these — American Atlas, North American Pilot, and West Indian Atlas — were published after his death by his successor, William Faden.

At Faden’s establishment the first sheets of the Ordnance Survey maps were engraved, until that department secured a staff and offices of its own. Contemporary with Faden was John Cary, who maintained a high standard of excellence in his maps and globes.

Both these men gave much attention to preparing new maps of the British Isles, utilizing the numerous county surveys, and later the early editions of the Ordnance Survey sheets, besides adding much detail from their own work.

Cary in particular paid attention to the rapidly developing system of communications; in 1794, he was engaged by the Postmaster General to supervise the survey of some nine thousand miles of turnpike roads in Britain.

The results were incorporated in various road books and county atlases, the latest and largest of which was the folio ‘New English Atlas’ of 1809.

Aaron Arrowsmith and international reputation

But the man who established the international reputation of British cartography was undoubtedly Aaron Arrowsmith.

A native of Winston, Durham, Arrowsmith was typical of the generation which gave Britain its lead in the technical revolution of the eighteenth century.

With no advantages of birth, or systematic education, he acquired a knowledge of mathematics, and of the theories of map projections, and through a long apprenticeship became proficient in the practical technique of map production.

He came to London in 1770, and worked for some time as a land surveyor; as such he is described on Cary’s ‘Map of the Great Post-Roads between London and Falmouth’ of 1784, for which he was largely responsible.

It is possible that it was in Cary’s establishment that he learned the technique of map engraving. However that may be, he set up for himself as a cartographer and map publisher some time before April 1790.

His first publication, a chart of the world on Mercator’s projection, which when mounted had the considerable dimensions of 5 ft. by 8 ft. 4 in., was an immediate success.

This included the tracks of the most important navigators since the year 1700, all “regulated from the accurate astronomical observations” taken on the three voyages of Capt. James Cook.

Arrowsmith’s method and works

It was his proficiency in ‘regulating’ observations from varied sources and in fitting together sketch maps or reports by numerous explorers and travellers that gave Arrowsmith his pre-eminence.

His fame also owed something to the style of engraving.

The names are clearly engraved, and much detail is given without confusion. Save for the title cartouches, the maps are entirely without decorative details, behind which lack of knowledge so often had taken refuge.

On his maps in general, relief is poorly represented; he considered that altitudes could not be introduced except on very large scales.

Four years later, this map, which in his words met with “great approbation’’, was followed by another of the world on the globular projection, published with a ‘Companion’, in which he set forth his opinion that the Mercator and globular projections were the most suitable on which to represent the whole surface of the globe.

For this second map, he had corrected the positions of some hundreds of places, and considered that “‘as far as the name can apply to a map”, it was “an original work’’.

In the ‘Companion’, Arrowsmith lists nearly 140 authorities on which he had drawn, including a number of manuscript maps of the Hudson’s Bay Company’s territories by Philip Turnour, astronomical observations by Cook’s officers, and three maps of the country north of Fort Churchill by an Indian.

Alexander Dalrymple had also presented him with a complete set of his geographical publications, including 623 maps and charts.

Later productions and legacy

It is not possible to list here all Arrowsmith’s productions, but notable among them are his chart in nine sheets of the Pacific Ocean, 1798, the dimensions of which when mounted are over 6 ft. by 7 ft. 6 in., and which is now a valuable source for the history of Pacific exploration; his maps, nineteen sheets in all, published in conjunction with Thompson’s ‘Alcedo; or dictionary of America and West Indies’, and based on original materials “that have till lately remained inaccessible at Madrid and at Lisbon”.

After his death in 1825, his business was carried on for a time by his sons Aaron and Samuel, but was later taken over by his nephew, John (1790-1873), who maintained his uncle’s reputation.

He was closely in touch with the explorers of Australia, working up and publishing their maps.

Abandoning his uncle’s practice of issuing large maps suitable for mounting as wall maps, which had alternatively to be bound somewhat inconveniently in sheets, he worked for a number of years on the sheets of an atlas, uniform in size and style.

When published in 1840 as “The London Atlas of universal geography” it was the best of its kind as a political and location atlas.

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