The Nauscopy Wizard of Mauritius

October 13, 2011 4:25 PM

In 1782, a French colony in the Indian Ocean prepared for a rumored assault by British ships. Before the governor's reconnaissance ship could report back on the flotilla, however, a member of the local engineering corps reported that the group of ships had changed course. Etienne Bottineau claimed to be the inventor of a whole new “science” that he called nauscopy: “The art of discovering ships and land at a great distance.”

Over the course of his 'career,' "The Wizard of Mauritius" had an outstanding track record. He never fully explained his mysterious method, though he claimed that he could detect "manifestations on the horizon" that "became more and more closely connected… with the presence of ships at varying degrees of invisibility…. They grew clearer as the ship, or ships, approached; fainter as they receded."

posted by mudpuppie (16 comments total)

Pshaw. Clearly he just used a curved telescope.
posted by Sparx at 5:01 PM on October 13, 2011

I knew a construction worker once, who spent a morning going around the camp making (significantly more minor) predictions. He'd take off his hardhat, use it to block the worst of the sun's glare, and then confidently state the time based on the height of the sun in the sky. He was invariably right down to the minute, and could predict on demand.

By the time he got to me he'd been doing this for a few hours, and was happy to explain how. He'd taken a digital watch, removed the straps, and taped it to the inside of his hardhat.
posted by Orange Pamplemousse at 5:10 PM on October 13, 2011 [17 favorites]

Easily explained - Specters in the Air
posted by Bighappyfunhouse at 5:33 PM on October 13, 2011

How to Recognize Different Ships From Quite A Long Way Away:

#1: THE LARCH
posted by lumensimus at 5:38 PM on October 13, 2011 [11 favorites]

It may have to do with polarized light - this article on turtles - has an interesting comment - We do know that many turtle species can see polarized light, and use that to see the signature reflections in the sky of waterbodies on the horizon.
posted by Bighappyfunhouse at 5:48 PM on October 13, 2011 [1 favorite]

Yes, but even if a human had some acuity for detecting polarized light, a ship over the horizon would be a tiny spot of non-polarized light against an entire sky of polarized light -- much harder to detect than the expanse of polarized light against a backgrground of non-polarized light that sea turtles use.

My money is on luck. Or a radar system donated by time travelers.
posted by miyabo at 7:52 PM on October 13, 2011

The big discoveries in the usefulness of polarized light were ~20 years later
posted by Blasdelb at 8:50 PM on October 13, 2011

People can see polarization, sort of: Haidinger's brush.

I'm not claiming this would let you see ships over the horizon, just something interesting that turned up looking up polarization on Wikipedia.
posted by nangar at 9:36 PM on October 13, 2011

This means that How to Avoid Huge Ships needs to be urgently updated
posted by quarsan at 9:49 PM on October 13, 2011 [1 favorite]

A little more on Haidinger's brush.
posted by nangar at 10:03 PM on October 13, 2011

If polarized vision allows you to see reflected images in the clouds - from hundreds of miles away - the question is - what could a man use - in 1782 - to increase his human polarized vision? (and don't tell me it's a turtle eye)
posted by Bighappyfunhouse at 10:30 PM on October 13, 2011

Maybe some funky meteor impact glass with just the right properties?
posted by CautionToTheWind at 2:00 AM on October 14, 2011

I can see Haidinger's Brush - AMA!

Err, sorry. Wrong site.
posted by kcds at 5:06 AM on October 14, 2011 [2 favorites]

Askmefi answers questions before its asked shocker!!

I was going to post to Ask about whether humans can sense polarisation to any degree, as I wondered what sense we had of the changes to the quality of light at dawn/dusk. When I am up early I can approximate the time by the quality of the light and I wondered if it was polarisation effects. I wondered this after reading about a bee that only comes out in the morning and evening and knows when the time is right as it can sense the polarisation.

So thanks for the Haidingers brush links.
posted by marienbad at 12:53 PM on October 14, 2011

I think it must have something to do with the Mauritius islands. Either, geography, an assisted view via polarized lens or something particular to the region. This is a mystery that can be solved with some effort.
posted by Bighappyfunhouse at 7:46 PM on October 14, 2011

It's very interesting to me that Bottineau is said to have "died lately in great misery at Pondicherry". Pondicherry is a former French colony on the East Coast of India, about two hours from Chennai, where I grew up. I had never heard of this man before and would be interested in learning more about his Pondicherry connection.
posted by peacheater at 7:34 AM on October 19, 2011