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I'll use an alternating current on the third wire, and see if that makes it any better. And I'll put in the most sensitive selenium plate I can make. I'm going to have this thing a success." Tom carefully examined the drawings of his invention, at which papers Mr. Boylan had confessed to looking.

Now, without a relative simplicity in the arrangement of the conducting wires intended to convey to a distance the electric current with its variations of intensity, without a perfect and rapid synchronism acting concurrently with the luminous impressions, so as to insure the simultaneous action of transmitter and receiver, without, in fine, an increased sensitiveness in the selenium, the idea of the telectroscope could not be realized.

"In fact, I have been working on a little device that I can attach to our cameras to cut down the amount of light automatically. It consists of a selenium plate with a battery attachment " "Oh, spare us the dreadful details!" interrupted Miss Pennington, who was of a rather frivolous nature. "Well, there is no longer need of detaining you," spoke Mr. Pertell. "Work for the day is over.

In 1875, 1876 and 1877, he investigated the action of light on crystalline selenium, and in 1878 he studied the action of the telephone. The recent work of Dr. Siemens has been to improve the pneumatic railway, railway signalling, electric lamps, dynamos, electro-plating and electric railways.

Another resemblance results also from the experiments by which M. Perreau established that these rays act on the electric resistance of selenium. New and valuable arguments have thus added force to those who incline towards a theory which has the merit of bringing a new phenomenon within the pale of phenomena previously known.

Rowland's own observations, although, of course, most of them have been given by others: Elements in the Sun, arranged according to Intensity and the Number of Lines in the Solar Spectrum. Not in Solar Spectrum. Antimony, arsenic, bismuth, boron, nitrogen, cæsium, gold, indium, mercury, phosphorus, rubidium, selenium, sulphur, thallium, praseodymium. With respect to these tables, Prof.

In an order of ideas different in appearance, but closely linked at bottom with the one just mentioned, must be recalled the discovery of radiophony in 1880 by Graham Bell, which was foreshadowed in 1875 by C.A. Brown. A luminous ray falling on a selenium cell produces a variation of electric resistance, thanks to which a sound signal can be transmitted by light.

Kennedy was busy adjusting the apparatus, and paused only to remark that the boxes contained two sensitive selenium surfaces balanced against two carbon resistances. There was also in the box a clockwork mechanism which Craig wound up and set ticking ever so softly.

"I think it is the only thing to use in this photo telephone experiment, though I might try the metal plate method, as they did between Monte Carlo and Paris. But I am not trying to make newspaper pictures." "What is selenium, anyhow?" asked Ned. "Remember, Tom, I'm not up on this scientific stuff as you are."

I'm going to use a still stronger current, and this is the most sensitive selenium plate I've turned out yet. We'll see if we can't get a better likeness of you one that will be plainer." It was Tom Swift who was speaking, and he and his chum had just completed some hard work on the new photo telephone. Though the apparatus did what Tom had claimed for it, still he was far from satisfied.