On June 21, 1838, Charles Wheatstone showed an amazing picture to the Royal Society of London, a picture which advanced the science of optics and helped to usher in the modern age. That picture looked like this:

And there were more pictures just like it. Wheatstone had drawn a batch of 11 simple drawings. Each one was a pair of doodles, the right one not quite identical to the left one. These doodles were designed to be inserted into a contraption which Wheatstone called his "stereoscope."

The stereoscope displayed one doodle to one eye, and the other doodle to the other eye. Nowadays, we achieve the same effect with anaglyph 3D glasses. Here is what amazed the scientists in 1838:

Wheatstone's treatise, published in volume 128 of Philosophical Transactions of the Royal Society of London, explained his research into this hitherto unknown property of optics. It is almost unbelievable that such an apparently self-evident truth was unknown until 1838, but there is in fact no record of anyone having made this discovery before.

You can buy a PDF of Wheatstone's 1838 article from Royal Society Publishing. But they want $49.00 for it! For one 170-year-old article, can you believe it? I bet they're not selling like hotcakes.

The complete text is available free online at the Stereoscopy.com Library, too.

Best of all, I have redrawn all 11 of Wheatstone's anaglyph examples for red/blue 3D glasses. Check them out.