The illustration shows the parallelism as well as can be done by a mere chart.
On the left-hand side is shown the manner in which a nerve-group is distributed to different parts of the body. On the right the railway telegraph wires are seen, and, as the reader will probably remember, branch wires are carried into the signal boxes, just as branch nerves are carried to the most distant parts of the body.
I have already mentioned the Electric Spark, and that it is, in fact, a miniature lightning-flash, the little crackling report being a miniature thunder-clap. It can be produced by frictional electricity, or by the voltaic pile in its many variations, or by animal substances alone, as in the case of the torpedo and electric eel.
We now come to a modification of the spark, whereby a continuous current of electricity is sent through two charcoal points, and inflames them with such intensity that the eye cannot look upon its dazzling whiteness. There is none of the yellowness about it which is so great a drawback to our artificial lights, whether they be gas, candle, or lamp, and which makes ladies’ dresses that are really beautiful by day look dull and almost ugly by night.
It is wonderful to see how the Electric Light kills all other lights. The brightest gas becomes dull, and its shadow is thrown on the wall which it formerly illuminated, and the most delicate tints of silks and satins suddenly display themselves in the blinding whiteness of the Electric Light.
At present it is too costly to be brought into common use, but its intensity is so great that serious ideas have been formed of dispensing with street lamps altogether, and illuminating towns with a few electric lamps placed at a considerable height, and having their beams reflected downwards.
London is thought to be a specially fit subject for this mode of lighting, as the electric beams can pierce the fogs which the gas-lamp only augments, and give the traveller some hope of finding his way through the most familiar streets.
In the illustration the right-hand figure represents the Electric Light as at present in use. The upper portion of the left-hand side represents the forked lightning, whose dazzling whiteness is so familiar to us, even in the noon of a summer’s day.