Today is the birthday (1512) of Gerardus Mercator, Flemish cartographer, instrument maker, philosopher and mathematician. He is best known for his work in cartography, in particular the world map of 1569 based on a new projection, the Mercator projection, which represented sailing courses of constant bearing as straight lines.
Mercator was born Gerard de Kremer or de Cremer in the town of Rupelmonde in the County of Flanders (modern-day Belgium) to parents from Gangelt in the Duchy of Jülich, where he was raised. “Mercator” is the Latinized form of his name. It means “merchant”. He was educated in ‘s-Hertogenbosch by the famous humanist Macropedius and at the University of Leuven (both in the historical Duchy of Brabant). Despite Mercator’s fame as a cartographer, his main source of income came through his craftsmanship of mathematical instruments. In Leuven, he worked with Gemma Frisius and Gaspar Van Der Heyden (Gaspar Myrica) from 1535 to 1536 to construct a terrestrial globe, although the role of Mercator in the project was not primarily as a cartographer, but rather as a highly skilled engraver of brass plates. Mercator’s own independent map-making began only when he produced a map of Palestine in 1537; this map was followed by another—a map of the world (1538) – and a map of the County of Flanders (1540). During this period he learned Italic script because it was the most suitable type of script for copper engraving of maps. He wrote the first instruction book of Italic script published in northern Europe.
Mercator was charged with heresy in 1544 on the basis of his sympathy for Protestant beliefs and suspicions about his frequent travels. He was in prison for seven months before the charges were dropped—possibly because of intervention from the university authorities.
In 1552, he moved to Duisburg, one of the major cities in the Duchy of Cleves, and opened a cartographic workshop where he completed a six-panel map of Europe in 1554. He worked also as a surveyor for the city. His motives for moving to Duisburg are not clear. Mercator might have left Flanders for religious reasons or because he was informed about the plans to found a university. He taught mathematics at the academic college of Duisburg. In 1564, after producing several maps, he was appointed Court Cosmographer to Wilhelm, Duke of Jülich-Cleves-Berg.
In 1569 he devised a new projection for a nautical chart. This cylindrical projection, now called the Mercator projection (although several other cartographers developed earlier versions), used for Mercator’s world map has several major advantages and several disadvantages. A ship travelling at a constant bearing is, in a sense, travelling in a straight line. But because the earth is spherical that “straight line” (known as a rhumb line) is really an arc of a circle. When plotted on a flat map on which the lines of latitude are equidistant (as they are on a globe), a rhumb line appears as an arc of a circle. Mercator’s projection increases the distance between lines of latitude in carefully calibrated increments as they move farther from the equator (becoming infinitely far apart at the two poles). The effect is to make rhumb lines straight on the map. This was an enormous benefit to maritime navigation. The disadvantage of the Mercator projection is that is seriously distorts the sizes of countries relatively near the poles. The map here, for example, shows Greenland as roughly the same size as Africa and larger than Australia, whereas in the later case Australia is over 3 times larger. In consequence Mercator projection is no longer used for general purpose maps.
Mercator took the word atlas to describe a collection of maps, and encouraged Abraham Ortelius to compile the first modern world atlas – Theatrum Orbis Terrarum – in 1570. He produced his own atlas in a number of parts, the first of which was published in 1578 and consisted of corrected versions of the maps of Ptolemy (though introducing a number of new errors). Maps of France, Germany and the Netherlands were added in 1585 and of the Balkans and Greece in 1588; further maps were published by Mercator’s son Rumold Mercator in 1595 after the death of his father.
Mercator learnt globe making from Gemma Frisius and went on to become the leading European globe maker of the age. Twenty-two pairs of his globes (terrestrial globe and matching celestial globe) have survived.
Following his move to Duisburg, Mercator never left the city and died there, a respected and wealthy citizen.
Waterzooi is a very old Flemish dish normally associated with the city of Ghent. It was originally a peasant dish but now can be found in elegant restaurants. It is loaded with a variety of vegetables, and the choice is really up to you. I give you here a good example. Use root vegetables in the main, and do not use leafy ones. The dish was originally made with river fish, but these days is almost always made with chicken. I make it with fish usually, but I am giving you the normal modern chicken recipe because river fish can be hard to come by in most parts of the world. In Argentina it is quite common.
3 leeks, cleaned and chopped
½ celeriac, peeled and coarsely shredded
3 carrots, peeled and diced
1 onion, peeled and diced
4 potatoes, peeled and diced
2 stalks celery, chopped
2 quarts/2 lt chicken stock
1 cup /2 dl cream
juice of 1 lemon
2 egg yolks
Melt the butter in a large heavy pot and sauté the vegetables for 4 to 5 minutes.
Add the chicken and the chicken stock. Add salt and pepper to taste.
Bring to a boil, cover, and simmer for 45 minutes.
Reduce the broth to a slow simmer. Take the chicken from the pot, remove the skin, and cut the meat from the carcass in large pieces.
Beat the egg yolks and cream in a bowl, and then add ½ ladle of the broth to the mixture, whisking constantly. Add this mix to the broth while stirring constantly to incorporate it quickly and thoroughly. If you do not follow these two steps the eggs will curdle. Add the lemon juice.
Return the chicken pieces to the soup. Let them heat through and serve the soup in deep bowls with desem (sourdough) rolls, or a baguette.