No comment is necessary on his interesting achievements in this field; the famous London lecture published in this volume is a proof in itself. But on the whole I find it» preferable when using such high frequencies to employ only one electrode and one con- necting wire. To attain great sensitiveness it is necessary to have the small sphere s in the centre of the globe L, as otherwise the electrostatic action of the glass of the globe will tend to stop the rotation. The greater part of the energy supplied to be bulb is then used up in heating the metal tube, and the »izlb is rendered useless for the purpose. The condenser charged from this coil discharges into the primary circuit of a second coil through a small air gap, which is necessary to produce a sudden rush of current through the primary. These and some foregoing remarks of a speculative nature were made merely to bring out curious features of alternate currents or electric impulses.
Some experiences have already been gained in this direction, and I will dwell on them briefly, in the hope that they might prove useful. I grasp it, and a platinum button mounted in it is brought to vivid incandescence. After the U-shaped tube was fitted and put in place, it was heated, so as to soften and take off the strain resulting from imperfect fitting. It is contained in a box B Fig. If the difference of potential between the terminals Is raised, the dielectric breaks down. It has 384 pole projections, and is capable of giving currents of a frequency of about 10,000 per second. In the experiment before shown, in which a brush appears at a wire attached to one terminal, and the wire is vibrated when the experimenter brings his insulated body in contact with the other terminal of the coil, the sudden rise of potential was made evident.
I have here a short and wide tube which is exhausted to a high degree and covered with a substantial coating of bronze, the coating allowing barely the light to shine through. The bulb consists in this case of a lamp globe L, which has a neck n, provided with a tube b and small sphere s, sealed to it, so that two entirely independent compartments are formed, as indicated in the drawing. Here is a simple glass tube from which the air has been partially exhausted. Electrodes made of ordinary carbon buttons were decidedly more durable when the buttons were obtained by the application of enormous pressure. That this statement is appli- cable to the subject of this lecture the many curious and unexpected phenomena which we observe afford a con- vincing proof. I wind the coil within an oil tank so that all interstices are filled up with the oil.
For instance, the experimenter may, by selecting a proper position, api roach the hand at a certain considerable distance to the bulb, and he may cause the brush to pass off by merely stiffening the muscles of the arm. When a coil is operated with currents of very high frequency, beautiful brush effects may be produced, even if the coil be of comparatively small dimensions. The powder, which is obtained from the crystals in some way, is practically non-conducting. So well known is this apparatus, so familiar are these phenomena to every one, that my courage nearly fails me when I think that I have ventured to address so able an audience, that I have ventured to entertain you with that same old subject. The typogrraphy Is excellent, being large and bold, and so arranged that each urord catcher the eye at a glance by standing out In sharp relief from the page. The effects of capacity are the most striking, for in these exper- iments, since the self-induction and frequency both are high, the critical capacity is very small, and need be but shghtly varied to produce a very considerable change.
In whatever position I may put it, wherever I may move it in space, as far as I can reach, its soft, pleasing light persists with undiminished brightness. The sensitiveness is likewise affected by the variations of temperature. Early in 1887 the Tesla Electric Company of New York was formed, and not long after that Mr. Tesla became a very fair example of high thinking and plain living, but he made up his mind to the struggle and determined to go through depending solely on his own resources. In operating an induction coil with rapidly alternating Qurrents, we realize with astonishment, for the first time, 51 the great importance of the relation of capacity, self-in- duction and frequency as regards the general result. In this case, since there are no large plates or other bodies of capacity attached to the terminals, the coil is capable of an extremely rapid vibration. .
But, even with the means at hand this evening, I may succeed in imitating the spark of a Holtz machine. On the lower end is placed an outside conducting coating C, which connects to the wire w. If by some means or other we increase the intensity of the molecular, or atomic, vibration, the gas changes to 82 a white color. We cannot go very far with a blast, nor by con- fining heat in a furnace, but in an exhausted bulb we can concentrate any amount of energy upon a minute button. Of all the possible constructions, it seems that a spherical globe with the refractory body mounted in its centre is the best to employ.
About Google Book Search Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers discover the world's books while helping authors and publishers reach new audiences. It is of the greatest importance to employ the smallest possible button, in order to push the density very far. All these observations fascinate us, and fill us with an intense desire to know more about the nature of these phenomena. Tesla's patents an Nikola Tesla was a genius polymath, inventor and a mechanical and electrical engineer.
When the necessary ad- justments in the length and distance of the wires above the oil and in the arc of discharge are made, a luminous sheet is produced between the wires which is perfectly smooth and textureless, like the ordinary discharge through a moderately exhausted tube. It has been recently produced by Mr. What a difference there is between these phenomena! The advantage of such a coil is that it can be easily handled, but it cannot probably give as satisfactory results as a coil immersed in pure oil. Up to this time he had never realized the enormous sacrifices that his parents had made in promoting his education, but he now began to feel the pinch and to grow unfamiliar with the image of Francis Joseph I. Kvery thinker, when considering the barbarous methods em- ployed, the deplorable losses incurred in our best systems of light production, must have asked himself, What is likely to be the light of the future? After three years of absence he returned home, sadly, to see his father die ; but, having resolved to settle down in Austria, and recognizing the value of linguistic acquirements, he went to Prague and then to Budapest with the view of mastering the languages he deemed necessary.