A paper on wireless telegraphy, Nov. 1905

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towards one of the sticks, but will be repelled by the other stick; if this end is the +ve end of the needle, then it will always move towards the sealing-wax, and it will be generally found that the sealing-wax attracts all +vely charged objects while it repels all negatively charged ones: and with glass this is vice versa. Now if the object, say a +ve pith ball, actually comes in contact with the wax stick, the stick no longer attracts it, but repels it, showing that the pith ball has taken some of the negative charge from the wax. Therefore this ball is negatively charged now. And if we similarly +vely charge a pith ball, by putting it in contact with the glass stick, and then place the 2 pith balls (which must always be held by a short piece of thread (silk) tied through a hole in them) near together, it will be found that they attract one another. We can therefore see now that unlike poles attract and like poles repel.

Leyden jar Whimshurst Discharge rod & "balls".

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It must also be noticed that if we produce, say, a positive charge in a body, we also produce a negative charge in the body, or medium, which produces the positive charge, e.g. +ve on the glass stick and -ve on the silk. Now if a ball is charged strongly with a positive charge of electricity and we connect it to earth by means of one's knuckles, a spark is seen to jump across. This spark that we see is the actual electrical discharge of the ball. This discharging phenomena is the Fundamental principle on which the present day wireless telegraphy is based.

Here is a Leyden jar, and if we charge it +vely inside and -vely outside by means of this Wheatstone electric charging machine, we can discharge this jar by connecting the 2 'poles' together by means of a metallic rod. The jar is at once discharged, but it will

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be noticed that before the connection is complete, that is, when one pole, say, the (+ve) ball is a little distant from the top end of the metallic rod, that the charge 'jumps' across the air space, being so ready, as it were, to discharge itself. Similarly if two large balls are charged differently & placed slowly towards one another, they will discharge with a 'crack'.

Now it was discovered early in the 18th century that this discharge had a distinct effect on the surrounding bodies. This was the beginning of wireless telegraphy.

It was also discovered that if a current was passed through a wire, a distinct effect was produced in another wire running parallel to it (but insulated from it) at a short distance. It might be said that this effect was produced by