A man who went through several diverse professions in his lifetime, Sir David Brewster is remembered most as the inventor of the Kaleidoscope. Born on the 11th of December in 1781, he was originally educated (and actually became licensed) as a minister of the Church of Scotland, but he apparently found science to be more his cup of tea. Brewster had had an interest in the properties of light from an early age, having built a telescope at the age of ten. So that was the discipline he followed when in the University of Edinburgh (which he entered at the age of 11).

Brewster eventually became a teacher at St. Andrews and was later promoted to principal there. He was elected a Fellow of the Royal Society in 1815, was a founder of the British Association for the Advancement of Science, and was responsible for numerous inventions. Then, in 1859, he left St Andrews to become Principal of The University of Edinburgh. Most accounts indicate that he was well liked by his students, but often had a tendency to be quite quarrelsome in his dealings.

Working primarily in the field of optics and polarized light lead him to his most well known invention, the Kaleidoscope. He discovered that when he placed mirrors, loose pieces of glass, and other objects inside a tube, one could see patterns when looking through the end of the tube. He named his invention from a combination of several Greek words, "kalos" (beautiful), "eidos" (form), and "scopos" (viewer). So Kaleidoscope means "beautiful form viewer". Initially it was meant to be a scientific tool, but it was more popular as a toy and quickly became a fad. Unfortunately for Brewster, his patent for the device wasn't filed correctly, allowing others to imitate it.

He also left his mark on existing devices, most notably the stereoscope. This was a device that, using two lenses and two pictures taken from slightly different perspectives, provides the illusion of depth/three dimensions to the viewer. If this sounds familiar, then chances are you're old enough to remember the good old ViewMaster, which is based on a similar principle. After Brewster made some improvements to the stereoscope, it also caught on as a fad.

In addition to being an inventor and innovator, Brewster also had significant influence over the development of photography, which was still in its growing stages during his life. Additionally, he wrote several books, including Treatise on Optics (1831) and a biography of Sir Isaac Newton (1855), among numerous other publications. Elected a Fellow of the Royal Society in 1815, Brewster was something of a celebrity and had quite an illustrious circle of friends. Among them were writer Sir Walter Scott and painter Alexander Nasmyth. By the standards of the day Brewster lived quite a long life, dying on February 10th, 1868 at the generous age of 87.