Some of Tesla's Experiments Simplified - Commentary 2

Editor's note: This article contains commentary on the original article: Some of Tesla's Experiments Simplified.

[33984.] — While experimenting with an induction coil some time ago; I succeeded in producing an effect which I have never seen described, and if it be a real novelty, will probably be interesting to readers of the "E. M." The effect in question was produced by placing an electric incandescent lamp between the secondary terminals of the coil, when the bulb was instantly illuminated with a strong blue glow. It is necessary to state that the filament of the lamp had been broken off, the vacuum being still maintained. I was struck by the experiment, and tried an uninjured lamp in the same position, but could get no result with it. I then took the former lamp and covered half the bulb (the part farthest from the lamp terminals) with tinfoil, pasting it on carefully. The result when tried with the coil was almost magical. The finest effect was got by connecting the lamp terminals to one terminal of the coil, the other being connected to the tinfoil on lamp. A brilliant effect could also be produced by connecting the lamp to one coil terminal while any earth-connected conductor was allowed to touch the tinfoil. Finally I found that it was quite sufficient to hold the lamp in the hand at a distance of as much as a yard from the coil, whilst the latter was working, to get a good effect. No doubt the action of the lamp was similar to that of a vacuum tube; but it should be remembered that in the case of the lamp, only one conductor penetrated into the interior of the bulb. I should mention that the coil was built to produce ¼in. sparks, and is well-made and insulated.

An idea suggested by one of, Tesla's experiments is to pass the secondary current from one coil into the primary of a second coil, in order to produce sparks of a considerable length. I have had no chance of trying this arrangement yet. I would suggest that the insulation of the second coil should be perfection, and that perhaps a condenser would be advantageous. If the arrangement were workable, it is evident that long sparks might be obtained from a couple of small coils, costing together considerably less than one constructed to give the whole spark outright.

F. E. P.