The element selenium, when in crystalline form, possesses the peculiar property of being electro-sensitive to light. It is a good or bad conductor of electricity according to the intensity of the light that falls upon it, and its response to variations of illumination is virtually instantaneous.
This interesting property has been utilized in a wide variety of applications, ranging from the transmission of a picture over a telegraph line to the automatic detection of comets; but by far the most marvelous application is that of the phonopticon.... It is an apparatus that will actually read a book or a newspaper, uttering a characteristic combination of musical sounds for every letter it scans.
The principle of operation is not difficult to understand. A row of, say, three tiny selenium crystals is employed, each crystal forming part of a telephone circuit leading to a triple telephone-receiver. In each circuit there is an interrupter that breaks up the current into pulsations, or waves, of sufficient frequency to produce a musical note in the receiver. The frequency differs in the three circuits, so that each produces its characteristic pitch. Although the conductivity of selenium is increased by intensifying its illumination, the electrical connections in this apparatus are so chosen that while the crystals are illuminated no sounds are heard in the telephone, but when the crystals are darkened, there is an instant audible response.
The apparatus is placed upon the printed matter that is to be read, with the row of crystals disposed at right angles to the line of type. The paper directly under the crystals is illuminated by a beam of light. This is reflected from the unprinted part of the paper with sufficient intensity to keep the telephone quiet, but when the crystals are moved over the black printing, the light is diminished, and the crystals lose their conductivity, causing the telephone to respond with a set of sounds which vary with the shape of the letter. Suppose the apparatus was being moved over the letter V, the upper crystal would encounter the letter first, then the middle one would respond, next the lower one would come into action for an instant, followed by a second response of the middle crystal and a final response of the upper crystal. A set of notes would be sounded somewhat after this fashion: me, re, do, re, mi. The sound combination with such letters as S and O is more complicated but it is distinguishable. When we read with the natural eye we do not spell out the words letter by letter, but recognize them by their appearance as a whole. In the same way with the mechanical eye entire words can be recognized after a little practice.
Of course the phonopticon is yet in the laboratory stages, but it offers every prospect of practical success, and its possibilities are untold. It is quite conceivable that the apparatus may be elaborated to such an extent that a blind man may see (by ear) where he is going. His world may never be bathed in sunshine, but he may learn to admire the beauties of nature as translated from light into music.[61]
Aids in Gaining Interest
If mere clearness alone were the only quality to strive for, this kind of writing might remain, however useful, eternally dull except to one who is vitally interested in the facts, however they are treated. But for this there is no need; no reason exists why you should not make this kind of writing attractive. For you can, in addition to making a machine clear, endow it with life; in addition to enumerating the steps in a process, make it a fascinating adventure. Suppose that you are explaining how to learn to swim—is not the thought of waving one's arms and legs in dreamy or frantic rhythm as he lies prone across the piano bench humorous? Why, then, exclude the humor? And is not the person who is trying to learn much alive, with the pit of his stomach nervously aware of the hardness of the bench? Why, then, make him a wooden automaton, or worse, a dead agent? So long as you do not obscure the point that the reader should note, all the life, all the humor of which you and the process are capable should be introduced. Just so with a machine. You can explain the engine of an airship so that the reader will exclaim, "I see"; what you ought to do is so to explain the engine that he will say, "I see, and bless you, I'd like to see one go!" You ought to make the beautiful efficiency, the exquisite humming life of the thing, its poise, its athletic trimness so take hold of the reader that his imagination will be fired, his interest thoroughly aroused.
Now this you cannot do by thrusting in extraneous matter to leaven the lump. Webster in the Senate did not introduce vaudeville to enliven his Reply to Hayne, but he found in the subject itself the interest. First of all, then, study your machine, your process, your organization, until you see what its quality is, its spirit, until you are yourself aware of its life, and then make this live for your reader. A railroad locomotive should be made thrilling with its pomp and power, a military movement should be made an exquisitely quick piece of living constructive work, a submarine should have all the craft and the romance of a haunting redskin, the roasting of a goose should be made a process to rouse the joys of gluttony forevermore. Now to do this will require exercise of the imagination, and if you find yours weak your first duty is to develop it. If it is strong and active, on the other hand, allow it free play, only watching lest it may obscure the subject—for clearness is always first. There need, however, be no discrepancy between the two qualities. The following extract from an essay by Mr. Dallas Lore Sharp illustrates the possibilities of both interest and truth.