MERCATOR,
GERARDUS [latinized form of Gerhard KREMER] (1512 – 1594), Flemish mathematician
and geographer, was born at Rupelmonde, in Flanders, on the 5th of March
1512. Having studied at Bois-le-Duc and Louvain (where he matriculated
on the 29th of August 1530, and became licentiate in October 1532), he
met Gemma Frisius, a pupil of Apian of Ingolstadt, who at the request of
the emperor Charles V. had settled in Louvain. From Frisius young Kremer
derived much of his inclination to cartography and scientific geography.
In 1534 he founded his geographical establishment at Louvain; in
1537 he published his earliest known map, now lost (Terrae sanctae
descriptio). In 1537 – 1540 he executed his famous survey and map of
Flanders (Exactissima Flandriae descriptio), of which a copy exists
in the Musee Plantin, Antwerp. At the order of Charles V. Mercator made
a complete set of instruments of observation for the emperor's campaigns:
when these were destroyed by fire, in 1546, another set was ordered of
the same maker. In 1538 appeared Mercator's map of the world in (north
and south) hemispheres, which was rediscovered in 1878 in New York; this
work shows Ptolemy's influence still dominant over Mercatorian cartography.
In 1541 he issued the celebrated terrestrial globe, which he dedicated
to Nicolas Perrenot, father of Cardinal Granvelle: this was accompanied
by his Libellus de usu globi, which is said to have been presented
to Charles V. In 1551 a celestial globe followed. Mercator early began
to incline towards Protestantism; in 1533 he had retired for a time from
Louvain to Antwerp, partly to avoid inquiry into his religious beliefs;
in 1544 he was arrested and prosecuted for heresy, but escaped serious
consequences (two of the forty-two arrested with him were burnt, one beheaded,
two buried alive). He now thought seriously of emigrating; and when in
1552 Cassander, ordered by the duke of Juliers, Cleves and Berg to organize
a university at Duisburg, overed Mercator the
chair of cosmography the offer was accepted. The organization of the university
was adjourned, and never completed in Mercator's lifetime; but he now became
cosmographer to the duke and permanently settled on the German soil to
which many of his ancestors and relatives had belonged. Soon after this,
however, he paid a visit to Charles V. at Brussels, and presented the emperor
with a cosmos, a celestial sphere enclosing a terrestrial, together
with an explanatory Declaratio: this work marks . an era in the
observation of longitude by magnetic declination, perfected by Halley.
Charles rewarded the author with the title of imperatorii domesticus
(Hofrath in the epitaph at Duisburg). In 1554 Mercator published his
great map of Europe in six sheets, three or four of which had already been
pretty well worked out at Louvain; a copy of this was rediscovered at
Breslau in 1889. Herein, though still greatly under Ptolemy's influence,
Mercator begins to emancipate himself; thus Ptolemy's 62° for the length
of the Mediterranean, reduced to 58° in the globe of 1541, he now cuts
down to 53°. On the 28th of October 1556 he observed
an eclipse at Duisburg; in 1563 he surveyed Lorraine, at the request of
Duke Charles, and completed a map of the same (Lotharingiae descriptio);
but it is uncertain if this was ever published. In 1564 he engraved
William Camden's map of the British Isles; in 1568 he brought out his Chronologia,
hoc est tempornm demonstratio... ab initio mundi usque ad annum domini
1568, ex eclipsibus et observationibus astronomicis. In the same year
was published his memorable planisphere for use in navigation, the first
map on "Mercator's projection,” with the parallels and meridians at right
angles (Nova et aucta orbis terrae descriptio ad usus navigantium accommodata).
Improvements were introduced in this projection by Edward Wright in
1590; the more general use of it dates from about 1630, and largely came
about through Dieppese support. In 1572 Mercator issued a second edition
of his map of Europe; in 1578 appeared his Tabulae geographicae ad mentem
Ptolemaei restitutae et ememdatae; and in 1585 the first part
(containing Germany, France and Belgium) of the Atlas, sive cosmographicae
meditationes de fabrica mundi, in which he planned to crown his work
by uniting in one volume his various detailed maps, so as to' form a general
description of the globe In 1585 he adapted his Europe to the Atlas;
in 1587, with the help of his son Rumold, he added to the same a world-map
(Orbis terrarum compendiosa descriptio), followed in 1590 by a second
series of detailed maps (Italy, Slavonia, Greece and Candia). The rest
of the regional and other plans in this undertaking, mostly begun by Gerard,
were finished by Rumold; they include Iceland and the Polar regions, the
British Isles (dedicated to Queen Elizabeth), the Scandinavian countries
(dedicated to Henr. Ranzovius), Prussia and Livonia, Russia, Lithuania,
Transylvania, the Crimea, Asia, Africa and America (in the last Michael
Mercator, in Asia and Africa Gerard Mercator the younger, assisted) The
designs are accompanied by cosmographical and other dissertations, some
of the theological views in which were condemned as heretical (see the
Duisburg edition of 1594, folio). In 1592 Mercator published, two years
after his first apoplectic stroke, a Harmonia evangeliorum. He died
on the 9th of December 1594, and was buried in St Saviour's church, Duisburg.
Besides his famous projection, he did excellent service with Ortelius in
helping to free the geography of the 16th century from the tyranny of Ptolemy;
his map and instrument work is noteworthy for its delicate precision and
admirable execution in detail.
See the Vita Mercatoris by Gualterus Ghymnius in
the Latin editions of the Atlas; Gerard Mercator, sa vie et ses oeuvres,
by Dr J. van Raemdonck (St Nicolas, 1869); A. Breusing, Gerhard
Kremer (Duisburg, 1878), and article "Mercator” in Allgemeine deutsche
Biographie; General Wauwermans, Histoire de l'école cartographique
belge... au XVI.-siècle, and article " Mercator” in Biographie
nationale (de Belgique), vol. xiv. (Brussels, 1897). Also the lesser
studies of Dr J. van Raemdonck, Sur les exemplaires des grandes cartes
de Mercator; Carte de Flandre de Mercator; Relations entreMercator et...
Plantin... (St Nicolas, 1884); La Geo-graphie ancienne de la Palestine:
Lettre de Gérard Mercator... mai 22, 1567 (St N., 1884); Les
Sphères terrestre et céleste de Mercator, 1541... 1551 (St
N., 1885); Van Ortroy, L'Oeuvre geographique de Mercator.
(C. R. B.)
Charles
R. Beazley
Map07.html#Gerhard Kremer
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