The lost art of Nauscopie

In France in 1762, one Monsieur Bottineau held an “inferior” position in “His Most Christian Majesty’s Navy.” That same year he formed a theory that a vessel approaching land must produce a certain effect on the atmosphere, making its approach evident to a person with a practiced eye, even before the vessel itself was visible above the horizon. After making numerous observations he discovered he could detect a particular appearance of the horizon before the vessel came in sight; but, being correct in his predictions less than half the time, he thought of giving up further observations.

In 1764 M. Bottineau was posted to the backwater French colony of Isle de France (now Mauritius) off Madagascar. His position allowed him much leisure time, so he began his “observations” anew in a climate that provided a clear sky on most days. Following a further six months of practice and success, Bottineau felt that he had discovered and perfected a new science that he proposed to call “Nauscopie.”

Isle de France was certainly not a place of plum assignments in the French colonies. The naval and military officers of the island led an idle life of debauchery and cards and spent a good deal of time on the shore with their telescopes, watching for vessels approaching from Europe. Bottineau frequently laid wagers that a vessel would arrive at a certain time, often as much as four days before she would appear above the horizon. He was rarely wrong in his predictions and soon amassed a large sum of money. The officers were puzzled at Bottineau’s ability since he used no telescope or other instrument in making his predictions, and soon no one would wager with him.

Finally, in 1780, Bottineau wrote to the minister of marine affairs in France, Marechal de Castries, announcing his discovery. De Castries wrote to the governor of Isle de France that he should record all of Bottineau’s predictions for the next two years in a register. This controlled series of observations began on May 15, 1782. On the 16th Bottineau announced to the governor that three vessels were near the island. Orders were then given to the “vigies,” or lookouts, to scan the horizon for signs of any vessels. Their report was negative. On the 17th, one lookout reported the “tops” of a vessel had been sighted just above the horizon; on the 18th, a second came in sight; and on the 26th, a third was visible. At this point, the Vicomte de Souillac, who knew of Bottineau’s earlier successes, offered him 10,000 livres on behalf of the government and a further pension of 1,200 livres a year to disclose his secret. Bottineau declined the offer, believing he could do much better.

In 1782 de Souillac wrote to de Castries that he truly believed that Bottineau had discovered a valuable art that allowed him to announce “the presence of one or several vessels at a distance of 100, 150 and even 200 leagues. Is this the result of study, or the application of some principles of science? By no means: all his science is in his eyes.” Further on in his letter, de Souillac writes that “Upon one occasion he asserted that a fleet of 11 vessels was approaching the island; the announcement caused great alarm, as we anticipated an attack from the English. A sloop of war was instantly dispatched to look out; but before she returned, M. Bottineau came to the governor, and informed him that the signs in the atmosphere had disappeared, and that the fleet had taken a different direction. Some time after this, a vessel arrived here from the East Indies, and reported that she had seen a fleet of 11 vessels sailing towards Fort St. William.” De Souillac’s letter continues, “From the year 1778 till 1782, he had announced the arrival of 575 vessels, many of them four days before they became visible.” The letter ends, “However incredible this discovery may appear, myself and a great many officers, naval and military, must bear testimony to the announcements made by M. Bottineau. We cannot treat him as an impostor, or as a visionary. We have had ocular demonstration for so many years, and in no instance has any vessel reached the island, the approach of which he had not predicted; those which did approach but did not touch the island, were in most cases proved to be foreign vessels.” The letter probably did reach the office of de Castries, but it is unlikely that his secretaries ever laid it before him since de Souillac never received a reply.

In the meantime, a frustrated Bottineau left Isle de France aboard one of King Louis’ vessels. During the voyage home he correctly announced the approach of 27 vessels to Capt. Dufour and, as the voyage continued, discovered that he could foresee their approach to land in a similar way. On one occasion he told Dufour that they were not more than 30 leagues from land. The captain replied that this was impossible. However, since the captain had seen Bottineau’s skills ably demonstrated, he decided to check his calculations. Upon re-examining his reckoning, he found it in error, altered course and apologized to Bottineau. Bottineau successfully found land three times on the voyage, once at a distance of 150 leagues.

All Bottineau’s attempts to see de Castries at Paris failed, and Abbe Fontenay, the editor of the Mercure de France, derided his theories. By this time France was aboil in the beginning tumult of the French Revolution, and M. Bottineau and his discovery disappeared into history.

Bottineau defined Nauscopie as “the art of ascertaining the approach of vessels, or, being in a vessel, the approach to land, at a very great distance.” When a vessel approaches land or another vessel, a phenomenon that he called a “meteor” became visible to him. When I checked a historical dictionary for the meaning of the term “meteor” in the 1700s, I found the following:

“Atmospheric phenomena were formerly often classed as aerial or airy meteors (winds), aqueous or watery meteors (rain, snow, hail, dew, etc.), luminous meteors (the aurora, rainbows, halo, etc.), and igneous or fiery meteors (lightning, shooting stars, etc.).”

Bottineau’s explanation of the art goes something like this. As animal and vegetable matter decay in the world’s oceans, vast amounts of various gases are released into the sea water where they remain trapped until the sea is agitated either by stormy weather or by the bow of a ship as it cuts through the surface of the water. When this happens, various gases and vapors escape and rise into the air in a smoke (fumee), establishing a vast envelope around the vessel. As the vessel proceeds, so does the envelope, and all the while the envelope grows in size. These “emanations” are like so many clouds that join to form one singular cloud (nappe) which projects forward, one end touching the vessel while the other advances forward a considerable distance. According to Bottineau, this vaporous cloud is not visible until it reaches vapors that emanate from the earth or another vessel, at which time the practiced eye can observe subtle changes in the atmosphere, which include visible changes in “consistence and color.” If the vessel sails on a fair wind the phenomenon is most pronounced, but contrary winds decrease the time frame of prediction. He stated that a storm would not destroy the effect but only retard it.

Unfortunately, M. Bottineau died before any of the great scientific minds of the age could interview him and examine his “art of Nauscopie.” We will never know if it might have advanced the art of navigation.

J. Gregory Dill, a sailor and nautical collector, lives in Dartmouth, Nova Scotia.

By Ocean Navigator