By: Regner & Joshua Ottens
Date: 1730 (Published) Amsterdam
Dimensions: 20.75 x 56.5 inches (55.25 cm x 143.5 cm)
This is an authentic, antique map of the world, produced by Regner & Joshua Ottens, and based on Edmund Haley’s study of magnetic fields. This is the first map to include isogonic lines and the first edition of Haley’s map to include wind directions. The map was published in Amsterdam circa 1730 and is three separate sheets that have been joined.
This is one of the most important world maps to come out of the 18th century, especially with regard to the study of Earth sciences. Being the first world map to include isogonic or Halleyan lines, this map depicts areas of equal magnetic variation across the oceans. Charting the phenomena of magnetic variations from “true north,” was considered a very important feature to have on a map, especially when it came to determining more accurate positioning of longitude. The map also includes several notations regarding trade wind directions and monsoons during specific months of the year. This feature would help mariners determine the best times of year to sail through certain areas of the world. The symbols he used to represent trailing winds still exist in most modern day weather chart representations.
Edmund Halley (1656 – 1742) was the second Royal Astronomer and is highly regarded as one of the greatest European astronomers of his era, along with Sir Isaac Newton. Though Halley had a large number of scientific discoveries and accomplishments, he is best known for the comet which bears his name as he correctly predicted its continuous return to Earth every 75 to 76 years. With relation to this map, Halley received temporary commission as a Captain of the Royal Navy in August of 1699 to make extensive observations on the conditions of terrestrial magnetism. This task he accomplished in a second Atlantic voyage which lasted until 6 September 1700, and extended from 52 degrees north to 52 degrees south. The results were published in General Chart of the Variation of the Compass (1701). This was the first such chart to be published and the first on which, isogonic or Halleyan, lines appeared.
Condition: This map is in A condition with narrow top and bottom margins and two rolled folds running vertically through the left sheet.
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