While experimenting with the complete circular mirror, which, it will be remembered, gave the most complicated forms, it occurred to me that a very vivid idea of how these curious wave surfaces are produced could be obtained by preparing a complete series in proper order on a kinetoscope film, and then projecting them in succession on the screen. The experimental difficulties were, however, too great to make it seem worth while to attempt to obtain a series of pictures of the actual waves, it being very difficult to accurately regulate the time interval between the two sparks. The easier method of making a large number of geometrical constructions, and then photographing them in succession on the film, was accordingly adopted. Three complete sets of drawings, to the number of about one hundred each, were prepared for three separate cases of reflection;—viz.: the entrance of a plane wave into a hemispherical mirror, the passage of a spherical wave out from the focus of a hemispherical mirror, and the multiple reflection of a spherical wave inside of a complete spherical mirror. Special methods were devised for simplifying the constructions, and much less labor was required in the preparation of the diagrams than one would suppose. The results fully justified the labor, the evolutions of the waves being shown in a most striking manner. These films I exhibited before the Royal Society in February last, and a more complete description of the manner of preparing them may be found in the Proceedings of the Society.
A portion of one of these series is reproduced, about one in four or five of the separate diagrams being given. The series runs from left to right in horizontal rows. When projected on the screen, the spherical wave is seen gradually to expand from the focus point, like a swelling soap bubble; it strikes the surface, and the bowl-shaped echo bounces off and follows the unreflected portion across the field; these two portions are then reflected in turn, and the curiously looped wave flies back and forth across the mirror, changing continuously all the time, and becoming more complicated at each reflection. These diagrams should be compared with the photographs shown in the fourth series.
One must not suppose that these beautiful forms exist only in the laboratory. Every time we speak, spherical waves bounce off the floor, ceiling and walls of the room, while in any ordinary bowl or basin the curious crater-shaped echoes are formed. Glance once more at the wave surfaces produced within a hollow sphere, and try to imagine the complexity of the aerial vibrations caused by a fly buzzing around in an empty water-caraffe! The photographs enable us to realize what is going on around us all the time—this our perceptions are fortunately too dull to perceive. Life would be a nightmare if we were obliged to see the myriads of flying sound waves bounding and rebounding about us in every direction, and combining into grotesque and ever-changing forms. It is just as well, on the whole, that the light of the electric spark and the delicate optical device of Toepler are necessary to bring them into view.
THE PSYCHOLOGY OF RED.
By HAVELOCK ELLIS.
Among all colors, the most poignantly emotional tone undoubtedly belongs to red. The ancient observation concerning the resemblance of scarlet to the notes of a trumpet has often been repeated, though it was probably unknown to the young Japanese lady who, on hearing a boy sing in a fine contralto voice, exclaimed: “That boy’s voice is red.” On the one hand, red is the color that idiots most easily learn to recognize; on the other hand, Kirchhoff, the chemist, called it the most aristocratic of colors; Pouchet, the zoölogist, was inclined to think that it was a color apart, not to be paralleled with any other chromatic sensation, and recalled that the retinal pigment is red; Laycock, the physician, confessed that he preferred the gorgeous red tints of an autumn sunset to either musical sounds or gustatory flavors. Artists more cautious than men of science in expressing such a preference—knowing that a color possesses its special virtue in relation to other colors, and that all are of infinite variety—yet easily reveal, one may often note, a predilection for red by introducing it into scenes where it is not naturally obvious, whether we turn to a great landscape painter like Constable or to a great figure painter like Rubens, who, with the development of his genius, displayed even greater daring in the introduction of red pigments into his work.
In all parts of the world red is symbolical of joyous emotion. Often, either alone or in association with yellow, occasionally with green, it is the fortunate or sacred color. In lands so far apart as France and Madagascar scarlet garments were at one time the exclusive privilege of the royal family. A great many different colors are symbolical of mourning in various parts of the world; white, gray, yellow, brown, blue, violet, black can be so used, but, so far as I am aware, red never. Everywhere we find, again, that red pigments and dyes, and especially red ochre, are apparently the first to be used at the beginning of civilization, and that they usually continue to be preferred even after other colors are introduced. There is indeed one quarter of the globe where the allied color of yellow, which often elsewhere is the favorite after red, may be said to come first. In a region of which the Malay peninsula is the center and which includes a large part of China, Burmah and the lower coast of India, yellow is the sacred and preferred color, but this is the only large district which presents us with any exception to the general rule, among either higher or lower races, and since yellow falls into the same group as red, and belongs to a neighboring part of the spectrum, even this phenomenon can scarcely be said to clash seriously with the general uniformity.[E]
[E] A further partial exception is furnished by the tendency to prefer green which may be found in certain countries, now or formerly Mahommedan, such as North Africa and to a large extent Spain, which have an arid and more or less desert climate.
If we turn to Australia, whither the anthropologist often turns in order to explore some of the most primitive and undisturbed data of early human culture still available for study, we find the preference for red very well marked. In times of rejoicing the tribes at Port Mackay, Curr remarked, paint themselves red; in times of mourning, white. In describing the paintings and rock carvings of the Australians, Mathews states that red, white, black and occasionally yellow pigments were used, precisely the four pigments which Karl von den Steinen found in use in Central Brazil. Prof. Baldwin Spencer and Mr. Gillen, in their valuable work on the natives of Central Australia, have pointed out the significance and importance of red ochre. One of the most striking and characteristic features, they say, of Central Australians’ implements and weapons is the coating of red ochre with which the native covers everything except his spear and spear-thrower. The hair is greased and red-ochred, and red ochre is the most striking feature in decoration generally. For ages past the Australian native has been accustomed to rub this substance regularly over his most sacred objects, and then over ordinary objects.