When, by a happy accident, Sir David Brewster had discovered the leading
principles of the kaleidoscope while repeating Biot's experiments on the
action of fluids upon light, he constructed an instrument in which he
fixed permanently, across the ends of the reflectors, pieces of coloured
glass, and other irregular objects. But it was not till some time
afterwards that the great step towards the completion of the instrument
was made, in the idea of giving motion to these objects, which were
placed loosely in a cell at the end of the instrument. When this idea
was carried into execution, the kaleidoscope in its simple form was
completed. The next and by far the most important step of the invention
was, to employ a draw tube and lens, by means of which beautiful forms
could be created from objects of all sizes, and at all distances from
the observer. In this way, the power of the kaleidoscope was
indefinitely extended, and every object in nature could be introduced
into the picture, in the same manner as if these objects had been
reduced in size, and actually placed at the end of the reflector.
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