History of Geography

by Sir John Scott Keltie; O. J. R. Howarth

Fig. 15.—Ramsden’s Theodolite.

The instruments and data available during the sixteenth and seventeenth centuries had been fairly effective in skilled hands for the observation of latitude, but observations for longitude remained very difficult. Regiomontanus had prepared ephemerides for 1474–1506, and Columbus used them; Peter Apianus made a series for 1521–70, but the results continued to be far from accurate till the appearance of Kepler’s Rudolphine Tables in 1526. Harrison’s work on the chronometer had been anticipated as early as 1530 by Gemma Frisius, who indicated the possibility of using a clock in determining longitude; but even Huygens’s clock was not found effective for this purpose. In 1735, however, John Harrison’s first chronometer appeared, and afforded the accurate measurement of time under varying conditions which is essential to the calculation of longitude. About 1737 Jonathan Sission produced a theodolite, and later in the century Ramsden’s greatly improved theodolite (actually a pioneer instrument, greatly though its type was afterwards modified in detail) was constructed and brought into use in the trigonometrical survey of England and Wales, which was begun in 1784.

Fig. 16.—Modern five-inch transit Theodolite.

Meanwhile in this period cartography underwent an evolution from ancient to modern methods. It is impossible here to attempt any catalogue of even the principal cartographers, and the work of a few must be taken as typical. In the earlier part of the period (sixteenth century) the marine chart was still the most generally valuable of the cartographer’s wares; but he was already extending his stock in other directions. Thus Gerhard Kremer (1512–94), more famous under the name of Mercator, is principally known for his chart of the world on the familiar rectangular projection which bears his name; but his other activities, besides the production of an atlas, included that of maps of various special areas; and he carried out survey work himself in Flanders as the basis of a map of that territory, which he produced in 1540. Not only the projection named after him, but also the secant conical, are usually attributed to Mercator. Edward Wright, a mathematician of Cambridge, produced the first English map on Mercator’s projection, which indeed has been stated to be actually Wright’s own invention; on this map we should observe the omission of various imaginary and erroneous details common to maps of the period—notably the southern continent. But the renewal of the study of map-projection was mainly owing to German mathematicians, such as Werner of Nuremberg, and Apianus, in the first two decades of the century. In Mercator’s work there are to be observed various tendencies towards modern practice, such as the abolition of the old small sketches or miniatures representing towns and divers other subjects, and the introduction of symbols. On the other hand, the period of the application of criticism by the cartographer to the data before him was not yet come. Mercator was content to supplement data, where imperfect, by imagination; and that tendency is to be observed in other work of the period, as, for example, in the astonishing conception of the hydrography of Africa set forth by F. Pigafetta in 1591. However, the application of criticism and prompt attention to new sources of information soon became recognized as cartographers’ duties. Thus, Nicolas Sanson of Abbeville, who founded a famous map-making establishment in 1627, made a common practice of citing his authorities; and again, promptly upon the work of Jean Picard (noticed above) and others, in the determination of positions from 1669 to the end of the century, there followed the production of a map of France corrected according to these observations, which were also used in other French publications. On some of these appears—first about 1674—the earliest rude representation of relief by hachures, though the old practice of the cartographer, of drawing relief in a species of perspective, and thereby making a molehill on his map out of a mountain in nature, was by no means yet superseded. It was more than half-a-century later that the cartographers hit upon the contour-line. M. S. Cruquius adopted this method of showing relief on a chart of the Merwede in 1728; P. Buache similarly showed the depths of the English Channel in 1737; J. G. Lehmann used contours as the proper scientific basis of hachuring in 1783, and a contoured map of France was produced in 1791 by Dupain-Triel. The atlas of Germany, begun by a famous cartographer of Nuremberg, Homann, and published in 1753, illustrates successive stages in the evolution of hill-shading; for the earliest map in the series, dating from thirty-five years earlier, shows the first endeavour to differentiate the shading according to the steepness of slope. In the meantime the use of maps had already been recognized in some of the many special departments of geographical science from which they are now inseparable. For example, the variation of the compass had been mapped by C. Burrus early in the seventeenth century, and was more effectively worked out by the famous astronomer E. Halley in 1683. A. Kircher, again, took an early step in the department of oceanography by mapping currents and other features of the oceans in 1665.

Fig. 17.—The World according to Mercator (1587).

From what has been written above, it may be inferred, and justly so, that Holland and France led the way in the development of cartography from the sixteenth to the eighteenth century. But by the end of the sixteenth century and throughout the seventeenth the mapping of most of the western European countries was rapidly extended, as in Germany, Austria, Switzerland, and Italy, in Denmark and Scandinavia, and in the British Isles. German local mapping ranked high, as appears from the collection in Ortelius’s Theatrum Orbis (1570) and from Mercator’s map of Germany (1585), both of which show the superiority of the cartographical material available for Germany. A large number of maps were based on original survey work. As early as 1566 a map of Bavaria by Philip Bienewitz, on a scale approximating (in terms of our survey) to two and a quarter miles to an inch, gave the results of a regular survey of remarkable accuracy for the period. Such was also the case (to select an example at home) with Christopher Saxton’s atlas of England and Wales (1574–79), in which the maps are about an inch to three miles in scale. This work marked the beginning of an important period in the history of British maps; Timothy Pont’s maps of Scotland appeared about 1608, and John Speed’s, of the British Isles on about the same scale as Saxton’s, in 1610. Hollar adopted a smaller scale (about five miles to the inch) in his maps of England and Wales dated 1644. These were of service in the Civil War, and the importance of military requirements in furthering the extension of organized survey work—which will appear in its subsequent history—is early exemplified in a survey of Ireland made under an Act of 1653; though this, the first British cadastral survey, was not a preliminary but a result of military operations, for it was made in connection with the parcelling of Irish lands among those who took part in the suppression of Irish rebellion. Again, the Scottish rebellion of 1745 led directly to a survey under Captain (afterwards General) Roy in 1747. It may be added here that in later cadastral work Ireland again took precedence of Great Britain: the six-inch survey begun in the former country in 1825 was nearly finished when that of Great Britain was undertaken in 1840.

France continued to lead the way in cartography in the eighteenth century. The maps of G. Delisle (1675–1726) and of J. B. B. D’Anville (1697–1782) were not merely confined to local work; they also included the presentation of cartographical material for distant lands selected according to truer scientific criteria. Thus D’Anville’s map of Africa, though preserving a few old inaccuracies, did away with details which were purely imaginary, and boldly revealed the then practically complete ignorance of the interior by representing it almost wholly as a blank. We may contrast this with earlier maps of the continent. Thus Waldseemüller (1516) showed waterways running parallel with the west coast, from north to south, and showed no conception of the Congo. Gastaldi (1564) marked the Zaire (Congo); but this and an east-flowing river and a branch of the Nile all flowed from a great central lake, Zembere. Mercator established a definite parting of the Nile, the Zaire, and the east-flowing system, though his ideas were still far from the truth.