The kaleidoscope

by David Brewster

When the inclination of the reflectors is great, the objects, or the fragments of coloured glass, should be larger than when the inclination is small; for when small fragments are presented before a large aperture, the pattern which is created has a spotted appearance, and derives no beauty from the inversion of the images, in consequence of the outline of each separate fragment not joining with the inverted image of it.

The objects which give the finest outlines by inversion, are those which have a curvilineal form, such as circles, ellipses, looped curves like the figure 8, curves like the figure 3 and the letter S; spirals, and other forms, such as squares, rectangles, and triangles, may be applied with advantage. Glass, both spun and twisted, and of all colours, and shades of colours, should be formed into the preceding shapes; and when these are mixed with pieces of flat coloured glass, blue vitriol, native sulphur, yellow orpiment, differently coloured fluids, enclosed and moving in small vessels of glass, etc., they will make the finest transparent objects for the Kaleidoscope. When the objects are to be laid upon a mirror plate, fragments of opaquely-coloured glass should be added to the transparent fragments, along with pieces of brass wire, of coloured foils, and grains of spelter. In selecting transparent objects, the greatest care must be taken to reject fragments of opaque glass, and dark colours that do not transmit much light; and all the pieces of spun glass, or coloured plates, should be as thin as possible.

When the objects are thus prepared, the next step is to place them in the object-box. The distance between the interior surfaces of the two plane glasses, of which the object-plates are generally composed, should be as small as possible, not exceeding ⅛th of an inch. The outermost of these glasses has its external surface rough ground, or is what is called a grey glass, the principal use of which is to prevent the lines of external objects, such as the bars of the window, or the outlines of the illuminating flame from being introduced into the picture. When a strong light is used, a circular disk of fine thin paper placed outside of the object-box may be advantageously employed in place of the ground glass. The thickness of the transparent glass plate next the reflectors should be just sufficient to keep the glass from breaking; and the interior diameter of the brass rings into which the transparent and the grey or ground plates of glass are burnished, should be so great that no part of the brass rim may be opposite the angular part of the reflectors during the rotatory motion of the cell. If this precaution is not attended to, the central part of the pattern, where the development of new forms is generally the most beautiful, will be entirely obliterated by the interposition of the brass rim. Instead of using transparent or grey glasses on the sides of every object-box, some of the boxes should be made with disks of flint glass, the interior surface of which have been stamped while in a state of fusion with a sort of pattern, or with curved lines of a pleasing form. In others, the outer surface alone of the plate next the reflectors might be thus formed. An object-box might also be formed of disks of glass, one side of which is colourless, and the other coloured, some of the coloured portions being ground away irregularly, as in certain Bohemian articles of glass; and the colour in one disk may be complementary to that in the other. In object-boxes of this kind, pieces of coloured glass may also be placed. When the two parts of the object-boxes thus constructed are screwed or fixed together, the box should be nearly two-thirds filled with the mixture of regular and irregular objects, already mentioned. If they fall with difficulty during the rotation of the cell, two or three turns of the screw backward, when there is a screw, will relieve them; and if they fall too easily, and accumulate, by slipping behind one another, the space between the glasses may be diminished by placing within the box another glass in contact with the grey glass.

When the object-box, now described, is placed in the cell, and examined by the Kaleidoscope, the pictures which it forms are in a state of perpetual change, and can never be fixed, and shown to another person. To obviate this disadvantage, an object-box with fixed objects generally accompanies the instrument; the pieces of spun and coloured glass are fixed by a transparent cement to the inner side of the glass of the object-plate, next the eye, so that the patterns are all permanent, and may be exhibited to others. After the cell has performed a complete rotation, the same patterns again recur, and may therefore be at any time recalled at the pleasure of the observer. The same patterns, it is true, will have a different appearance, if the light falls in a different manner upon the objects, but its general character and outline will, in most cases, remain the same.

The object-boxes which have now been described, are made to fit the cell, but at the same time to slip easily into it, so that they themselves have no motion separate from that of the cell. An object-plate, however, of a less diameter, called the vibrating object-plate, and containing loose objects, is an interesting addition to the instrument. When the Kaleidoscope is held horizontally, this small object-plate vibrates on its lower edge, either by a gentle motion of the tube, or by striking it slightly with the finger; and the effect of this vibration is singularly fine, particularly when it is combined with the motion of the coloured fragments.

Another of the object-boxes, in several of the instruments, contains either fragments of colourless glass, or an irregular surface of transparent varnish or indurated Canada balsam. This object-box gives very fine colourless figures when used alone; but its principal use is to be placed in the cell between an object-box with bright colours and the end of the instrument. When this is done, the outline of the pieces of coloured glass are softened down by the refraction of the transparent fragments, and the pattern displays the finest effects of soft and brilliant colouring. The colourless object-box supplies the outline of the pattern, and the mass of colour behind fills it up with the softest tints.

Some of the object-boxes are filled with iron or brass wires, twisted into various forms, and rendered broader and flatter in some places by hammering. These wires, when intermixed with a few small fragments of coloured glass, produce a very fine effect. Other object-plates have been made with pitch, balsam of tolu, gum lac, and thick transparent paints; and when these substances are laid on with judgment, they form excellent objects for the Kaleidoscope. Lace has been introduced with considerable effect, and also festoons of beads strung upon wire or thread; but pieces of glass, with cut and polished faces, are ill fitted for objects. When the object-box is wide, certain insects may be introduced temporarily, without killing or injuring them, and the crystallization of certain salts from their solution, and other chemical changes, may be curiously exhibited.

Hitherto we have supposed all colours to be indiscriminately adopted in the selection of objects; but it will be found from experience, that though the eye is pleased with the combination of various objects, yet it derives this pleasure from the beauty and symmetry of the outline, and not from the union of many different tints. Those who are accustomed to this kind of observation, and who are acquainted with the principles of the harmony of colours, will soon perceive the harshness of the effect which is produced by the predominance of one colour, by the juxtaposition of others, and by the accidental union of a number; and even those who are ignorant of these principles, will acknowledge the superior effect which is obtained by the exclusion of all other colours except those which harmonize with each other.

In order to enable any person to find what colours harmonize with each other, I have drawn up the following table, which contains the harmonic colours.

Deepest Red,	Blue and Green equally mixed.
Red,	Blue and Green, with most Blue, mixed.
Orange Red,	Blue mixed with much Indigo.
Orange,	Blue and Indigo, the Indigo predominating.
Orange-Yellow,	Indigo unmixed.
Yellow,	Violet and Indigo nearly in equal portions.
Greenish Yellow,	Pale Violet.
Green,	Violet.
Greenish Blue,	Violet and Red in equal portions.
Blue,	Orange Red, Red.
Indigo,	Orange-Yellow.
Violet,	Green.