“If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea.”
Antoine de Saint-Exupery
Ptolemy’s Almagest has been on the scientist’s best sellers list for centuries. But that wasn’t his only success. Ptolemy’s other best seller was called simply, Geography. And that is the only thing simple about it!
Geography was the first time anyone had ever presented the world with a detailed mathematical explanation for calculating lines of longitude and latitude. Ptolemy had a gift for amalgamating the cumulative knowledge of the ancient world into a systematic layout and design. He built on the work of Hipparchus and drew on the compilation of the known sailing directions, called periplus, collected from sailors far and wide. The Periplus of the Eritrean Sea, written in the first century by a Greek merchant living in Alexandria, provided invaluable data on the trading routes as far east as India.
Ptolemy’s greatest innovation was to record longitudes and latitudes in degrees for 8,000 locations on his world map, the first of its kind. He developed two ways of drawing grid lines on flat maps to signify the lines of longitude and latitude on the curved surface of the globe. In hindsight, there were many inaccuracies, such as the equator being too far north and Asia stretching too far to the east. Yet, it was the standard for over 1,300 years. Christopher Columbus was inspired by Ptolemy’s view of the world when he set sail for Asia and unexpectedly bumped into America. There are always surprises along the way.
“As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas, and land on barbarous coasts.”
Herman Melville, Moby-Dick