March 24, 2009 by D Stack
After getting home from work today I thought of a supplement to my previous post on Ada Lovelace. One of my all-time favorite series of fiction are Patrick O’Brian’s Aubrey/Maturin series of novels, profiling the British naval officer Jack Aubrey and his friend, Doctor Stephen Maturin, as they have adventures throughout the Napoloeonic Wars. For this discussion we shall advance a few more decades past the Age of Napoleon to the 1850s and profile a remarkable woman who was a record-setting navigator in a time when women rarely went to sea and, when they did, it was as passengers.
The job of a navigator at sea is to know his or her ship’s position at all times and to plot the course for the ship to follow. Without any GPS, determining a ship’s position was a very difficult task. There are two things that must be determined: a ship’s longitude and latitude. Latitude represents a ship’s position north or south of the equator. Determining this in the 19th century most commonly involved the use of an optical device known as a sextant to measure the position of a celestial object (such as the sun) at a specific time (usually noon). At night stars would be used. This would be used to calculate the vessel’s position by use of trigonometry.
Longitude represents position east or west of a specific point. It too can use celestial objects but is trickier to determine because the earth is constantly revolving on its axis, requiring the navigator to know the precise time, both locally and at a constant reference point (such as Greenwich, England). However, by the mid-19th century accurate chronometers were available making it possible to do this.
Don’t be fooled into thinking this was a trivial task. Navigation was far from staightforward and depending on practical familiarity with mathematics and use of tables of logarithms.
In the days of the California Gold Rush (around 1848 to 1855) people were in a hurry to get from the east coast of the United States to California as fast as they could. There were three basic routes:
- A land journey.
- A sea journey to Central America and then a land crossing to the Pacific Ocean and securing a second vessel.
- A sea journey all the way around the southern tip of South America (Cape Horn) and then heading back north.
The land journey was a dangerous one through territory not yet settled by the United States and was the most common route. The land-crossing of Central America shaved time off the journey but required securing passage on two ships as well as crossing a foreign country.
The problem with the voyage around Cape Horn was that it was a very long journey and typically took a long time – over 200 days. Clipper ships were the best option for this: narrow vessels optimized for speed. They weren’t useful for heavy cargoes but were geared more for valuable cargoes and passengers; perfect for a trip from New York to San Francisco.
This is Eleanor Creesy and her husband, Josiah Creesy, enter the story. Josiah was captain of the clipper ship Flying Cloud and Eleanor was the ship’s navigator. And what a navigator she was. Eleanor had been studying navigation since she was a girl from the Marblehead, at the North Shore of Massachusetts. Her father was her first teacher in navigation and she enjoyed the mathematics involved in this. She grew to become an expert in the study of weather, astronomy, and ocean currents. She studied the work of her time’s foremost oceanographer and navigator, M. F. Maury.
The Creesy’s twice set the record for the New York City to San Francisco voyage. The first time, in 1851, Flying Cloud made the trip in 89 days, 21 hours. Flying Cloud broke her own record, with the same husband and wife team, in 1851, making the trip in 89 days, 8 hours. This remained the record for the sail-powered journey until 1989. The two were celebrities for a short period of time, though sadly both died in relative obscurity.
Like Ada Lovelace, Eleanor Creesy was another remarkable woman of mathematics, showng how its practical uses could set records which would endure for well over a century.