Reflective symmetry has been observed since ancient times. Legend claims that early Egyptians would place two three or slabs of highly polished limestone together at different angles. It was not until 1816, that this optical phenomenon was encased in one small tube and given the name "The Kaleidoscope".
David Brewster was born in Jedburgh, on the 11th December 1781. At the age of only 10 years old he constructed his first telescope. In 1801 Brewster turned his great talents to two of his life - long interests, the study of optics and the development of scientific instruments. For twelve years he conducted a series of experiments that were revealed to the public in "A Treatise Upon New Philosophical Instruments" , published in 1813. In 1807, at the age of 26, the University of Aberdeen awarded him a Doctor of Letters degree, the highest literary distinction of that era. In 1808, he was elected a Fellow of the Royal Society of Edinburgh, and the same year became editor of the Edinburgh Encyclopaedia, a position he distinguished with excellence for more than 20 years.
It was in 1811, while writing an article on "Burning Instruments", Brewster investigated Buffon's Needle theory (considered to be the first problem in geometric probability). Brewster did not consider Buffon's proposal practical. However, it sparked an idea that produced awesome scientific results. In the course of his investigation he constructed a lens of great diameter out of one piece of glass by cutting out the central parts in successive ridges like stair steps. Thus was born an apparatus of then unequalled power the polyzonal lens - a lens constructed by building it on several circular segments. This useful discovery, which created light stabs of brilliance that could pierce far into the night, was later perfected and named after French physicist A.Fresnel, and resulted in the lighthouse as we know it today.
This breakthrough was followed by yet other honours. Brewster was admitted to the Royal Society of London, and was later awarded the Rumford gold and silver medal for his theory on the polarization of light. Ambient light, which comprises most of the light we encounter every day, is a collection of light waves vibrating in all directions. When light is reflected or it passes through certain materials, the waves tend to vibrate in a single direction. Light that vibrates in this more orderly fashion is polarized. Brewster discovered a simple way to calculate the angle at which light must strike a substance for maximum polarization. Brewster's Angle is useful in all kinds of practical applications, from adjusting radio signals to building microscopes capable of examining objects on a molecular scale. It is central to the development of fibre optics, lasers, and to the study of meteorology, cosmology. Success followed success, and in 1816, the Institute of France adjudged him 3,000 francs - half the prizes given that year for the two important scientific discoveries made in the two previous years.
At the age of 35, Brewster added another invention to his collection and invented the kaleidoscope. Buy this time he was already an established philosopher, writer, scientist, and inventor. However while Brewster was granted a patent for his kaleidoscope,
as well as acknowledgment and acclaim for his invention, he did not realize any remuneration, Others did. There was some fault with the patent registration, and before Brewster could claim any financial rewards,
kaleidoscopes were quickly manufactured by aggressive entrepreneurs who sold hundreds of thousands with great financial success for themselves.
In 1832 David Brewster was knighted by King William IV and in 1838 he was appointed Principal of the University of St Andrews, he was the first layman to be appointed Principal, a post which he held for 20 years. He left the University of St Andrews and became the Principal of Edinburgh University in 1859.
He died in 1868 aged 87.
