The kaleidoscope was invented in 1816 by Scottish scientist Sir David Brewster. He named his invention after the Greek words kalos (beautiful), eidos (form), and scopos (watcher).
Brewster’s kaleidoscope was a simple tube containing loose pieces of coloured glass and other objects, reflected by mirrors or glass lenses that created patterns when viewed through one end of the tube. It proved to be a huge success with 200,000 kaleidoscopes sold in London and Paris in just three months.
Brewster believed he would make a fortune from his invention, but a fault in his patent application allowed others to copy it. An American called Charles Bush (1825-1900) improved the design and became the first person to mass manufacturer a “parlor” kaleidoscope in North America.
The kaleidoscope works because of multiple reflections, where several mirrors are placed at an angle to one another. Typically there are three rectangular mirrors set at 60° to each other so that they form an equilateral triangle. The 60° angle generates an infinite regular grid of duplicate images of the original, with each image having six possible angles and being a mirror image or not.
As the tube is rotated, the objects tumble around presenting different colour combinations and configurations. Arbitrary patterns turn into symmetrical designs created by the reflections. A two-mirror kaleidoscope yields an arrangement isolated against a solid black background, while the three-mirror (closed triangle) type yields an array that fills the entire field.
The kaleidoscope has become a metaphor for life and thought. Throw enough ideas together and something worthwhile is likely to emerge, although it may not be entirely new, merely another way of looking at things. As Mark Twain pointed out in A Biography (1900-1907):
“There is no such thing as a new idea. It is impossible. We simply take a lot of old ideas and put them into a sort of mental kaleidoscope. We give them a turn and they make new and curious combinations. We keep on turning and making new combinations indefinitely; but they are the same old pieces of colored glass that have been in use through all the ages.”
Of course, another old prophet with the gift of the gab was there before him: “What has been will be again, what has been done will be done again; there is nothing new under the sun.”