1859 Maury Map of Indian Ocean Monsoon and Trade Winds

This is Matthew Fontaine Maury's seminal 1859 map of Indian Ocean monsoon winds, a practical tool meant help navigators plot the best routes throughout the year and significantly reduce their transit times. The map represents the culmination of Maury's remarkable efforts to map the Indian Ocean's complex seasonal currents.

A Closer Look

Two maps occupy the lower half of the sheet. The map on the left details Indian Ocean monsoon winds in February, when the northeast monsoon is dominant, while the map on the right depicts the monsoon winds in August, when the southeast monsoon dominates. The chart situated in the upper half of the sheet illustrates changes in latitude of the doldrums and winter monsoons over the course of a year (separated into groups of five degrees of longitude). The explanation in the upper right corner (dated January 1860) states that the chart was compiled as the result of 16,914 separate observations.

A Confederate in a Union Job

Maury's wind charts were a seminal achievement in nautical mapping, but were sidelined and often ignored by subsequent generations. Maury was born in Virginia, and when tensions broke out into the American Civil War (1861 - 1865), he returned to join the Confederacy. This act cast a pall over his relationships with his staunchly Union compatriots, particularly Alexander D. Bache, head of the U.S. Coast Survey. Bache spent much of his significant political capital sidelining Maury's work. Despite its groundbreaking reach and navigational utility, Maury's navigational works were never broadly disseminated. His work further fell out of fashion with the general rise of steamships, which made winds and current data less significant to navigation.

Maury on the Wind and Current Chart Series

This chart was part of Maury's influential Wind and Current Chart Series. Maury explained the series in the introduction to the 1855 edition of his book The Physical Geography of the Sea,

The primary object of the Wind and Current Charts, out of which has grown the Treatise on the Physical Geography of the Sea, was to collect the experience of every navigator as to the winds and currents of the ocean, to discuss his observations upon them, and then to present the world with the results on charts for the improvement of navigation.

Accordingly, when this object was made known, an appeal was addressed to the mariners, there was a flight up into the garrets, and a ransacking of time-honored sea-chests in all the maritime communities of the country for old log-books and journals.

It was supposed that the records therein contained as to the wind and weather, the sea and its currents, would afford information requisite for such an undertaking.

By putting down on a chart the tracks of many vessels on the same voyage but at different times, in different years, during all seasons, and by projecting along each track the winds and currents daily encountered, it was plain that the navigator hereafter, by consulting this chart, would have for a guide the results of the combined experience of all those whose tracks were thus pointed out.

Creating the Charts

After Maury became commander of the Depot of Charts and Instruments in July 1842, he was able to access the old logs of 'every voyage made by a commissioned ship in the Navy' which provided him with the necessary data to create his first charts. Not long after, Maury designed a data log and presented it to the Secretary of the Navy, who required all naval vessels to maintain these logs during every voyage. Since Maury's charts necessitated more data, he designed a much simpler chart than the one used by the Navy for use by merchantmen and convinced them to participate by offering free copies of his charts to any captain that provided data. Maury's influence, and that of the U.S. Naval Observatory and Hydrographical Office, became worldwide following the 1853 international conference on the ocean environment, where the major seafaring nations of the world adopted a log designed by Maury and 'agreed to cooperate in the collection of information for the betterment of navigation'.

Publication History and Census

This map was created by Matthew Fontaine Maury in 1859 from data compiled by Lieutenants J. J. Guthrie, H. S. Newcomb, N. H. Van Zandt, Cd. C. Stout, T. T. Houston, and projected by Lieutenant R. L. May. We note five examples cataloged in OCLC which are part of the collections at Yale University, Brown University, the Library of Congress, Stanford University, and the Bayerische Staatsbibliothek.