ABOVE: © SANDY GERRARD
One cloudy day in the early 1830s, Robert Addams, a traveling lecturer in chemistry and natural philosophy, found himself at the Falls of Foyers in Scotland, admiring the water of the River Foyers cascading down from the cliffs tens of meters above. Situated at the eastern shore of Loch Ness, the waterfall was a well-known beauty spot immortalized in the poems of Robert Burns.
It was here that Addams noticed a strange optical illusion. After staring a few seconds at the falling water, he moved his gaze to the rocks nearby and was surprised by the impression—albeit a fleeting one—that they were hurtling upwards. Intrigued, he put his experience into a letter to The London and Edinburgh Philosophical Magazine and Journal of Science that was published in 1834 as “An Account of a peculiar Optical Phænomenon seen after having looked at a moving Body, &c.”
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