When the Kaleidoscope was brought to this degree of perfection, it was impossible not to perceive that it would prove of the highest service in all the ornamental arts, and would, at the same time, become a popular instrument for the purposes of rational amusement. With these views I thought it advisable to secure the exclusive property of it by a Patent;[2] but in consequence of one of the patent instruments having been exhibited to some of the London opticians, the remarkable properties of the Kaleidoscope became known before any number of them could be prepared for sale. The sensation excited by this premature exhibition of its effects is incapable of description, and can be conceived only by those who witnessed it. “It very quickly became popular,” says Dr. Roget, in his excellent article on the Kaleidoscope in the Encyclopædia Britannica, “and the sensation it excited in London throughout all ranks of people was astonishing. It afforded delight to the poor as well as the rich; to the old as well as the young. Large cargoes of them were sent abroad, particularly to the East Indies. They very soon became known throughout Europe, and have been met with by travellers even in the most obscure and retired villages in Switzerland.” According to the computation of those who were best able to form an opinion on the subject, no fewer than two hundred thousand instruments were sold in London and Paris during three months. Out of this immense number there were perhaps not one thousand constructed upon scientific principles, and capable of giving anything like a correct idea of the power of the Kaleidoscope; and of the millions who have witnessed its effects, there is perhaps not a hundred individuals who have any idea of the principles upon which it is constructed, who are capable of distinguishing the spurious from the real instrument, or who have sufficient knowledge of its principles to be able to apply it to the numerous branches of the useful and ornamental arts.
Under these circumstances I have thought it necessary to draw up the following short treatise, for the purpose of explaining, in as popular a manner as I could, the principles and construction of the Kaleidoscope; of describing the different forms in which it is fitted up; of pointing out the various methods of using it as an instrument of recreation; and of instructing the artist how to employ it in the numerous branches of the useful and ornamental arts to which it is applicable.
CHAPTER I.
PRELIMINARY PRINCIPLES RESPECTING THE
EFFECTS OF COMBINING TWO PLAIN MIRRORS.
The principal parts of the Kaleidoscope are two reflecting planes, made of glass, or metal, or any other reflecting substance ground perfectly flat and highly polished. These reflectors, which are generally made of plate glass, either rough ground on their outer side, or covered with black varnish, may be of any size, but in general they should be from four or five to ten or twelve inches long; their greatest breadth being about an inch when the length is six inches, and increasing in proportion as the length increases. When these two plates are put together at an angle of 60°, or the sixth part of a circle, as shown in [Fig. 1], and the eye placed at the narrow end E, it will observe the opening A O B multiplied six times, and arranged round the centre O, as shown in [Fig. 2.]
Fig. 1.
Fig. 2.
