LECTURE II.
We were engaged in our last lecture in considering the various methods that have been adopted from early times for obtaining fire, and we left off at the invention of the lucifer match. I ventured to hint at the conclusion of my last lecture, that the tinder-box had something to say to the lucifer match, by way of suggestion, that just as the lucifer match had ousted it, so it was not impossible that something some day might oust the lucifer match. Electricians have unlimited confidence (I can assure you) in the unlimited applications of electricity:—they believe in their science. Now one of the effects of electricity is to cause a considerable rise of temperature in certain substances through which the electrical current is passed. Here is a piece of platinum wire, for example, and if I pass an electrical current through it, you see how the wire glows (Fig. 14). If we were to pass more current through it, which I can easily do, we should be able to make the platinum wire white hot, in which condition it would give out a considerable amount of light. There is the secret of those beautiful incandescent glow lamps that you so often see now-a-days (Fig. 15). Instead of a platinum wire, a fine thread of carbon is brought to a very high temperature by the passage through it of the electrical current, in which condition it gives out light. All that you have to do to light up is to connect your lamp with the battery. The reign of the match, as you see, so far as incandescent electric lamps are concerned, is a thing of the past. We need no match to fire it. Here are various forms of these beautiful little lamps. This is, as you see, a little rosette for the coat. Notice how I can turn the minute incandescent lamp, placed in the centre of the rose, off or on at my pleasure. If I disconnect it with the battery, which is in my pocket, the lamp goes out; if I connect it with my battery the lamp shines brilliantly. This all comes by "switching it on" or "switching it off," as we commonly express the act of connecting or disconnecting the lamp with the source of electricity.
Fig. 14.
Fig. 15.
Fig. 16.
Here is another apparatus to which I desire to call your attention. If I take a battery such as I have here—a small galvanic battery of some ten cells—you will see a very little spark when I make and break contact of the two poles. This is what is called an electrical torch, in which I utilize this small spark as a gas-lighter (Fig. 16). This instrument contains at its lower part a source of electricity, and if I connect the two wires that run through this long tube with the apparatus which generates the current, which I do by pressing on this button, you see a little spark is at once produced which readily sets fire to my gas-lamp. We have in this electrical torch a substitute—partial substitute, I ought to say—for the lucifer match. I think you will admit that it was with some show of reason I suggested that after all it is possible the lucifer match may not have quite so long an innings as the tinder-box. But there is another curious thing to note in these days of great scientific progress, viz. that there are signs of the old tinder-box coming to the front again. Men, I have often noticed, find it a very difficult thing to light their pipes with a match on the top of an omnibus on a windy day, and inventors are always trying to find out something that will enable them to do so without the trouble and difficulty of striking a match, and keeping the flame a-going long enough to light their cigars. And so we have various forms of pipe-lighting apparatus, of which here is one—which is nothing more than a tinder-box with its flint and steel (Fig. 17). You set to work somewhat in this way: placing the tinder (a) on the flint (b), you strike the flint with the steel (c), and—there, I have done it!—my tinder is fired by the spark. So you see there are signs, not only of the lucifer match being ousted by the applications of electricity, but of the old tinder-box coming amongst us once again in a new form.