Nikola Tesla - Free-Energy Devices

214 INVENTIONS OF NIKOLA TESLA.difficult. One thing is certain, at any rate, and that is, that inaugmenting the potential and frequency we rapidly intensify thestreams ; and, though it may be very sanguine, it is surely notaltogether hopeless to expect that we may succeed in producinga practical illuminant on these lines. We would then be simplyusing burners or flames, in which there would be no chemicalprocess, no consumption of material, but merely a transfer ofenergy, and which would, in all probability, emit more light andless heat than ordinary flames.The luminous intensity of the streams is,of course, considerablyFIG. 137.increased when they are focused upona small surface. Thismaybe shown by the following experiment:I attach to one of the terminals of the coil a wire w (Fig. 137),bent in a circle of about 30 centimetres in diameter, and to theother terminal I fasten a small brass sphere s,the surface of thewire being preferably equal to the surface of the sphere, and thecentre of the latter being in a line at right angles to the plane ofthe wire circle and passing throughits centre. When the dischargeis established under proper conditions, a luminous hollowcone is formed, and in the dark one-half of the brass sphere isstrongly illuminated, as shown in the cut.By some artifice or other it is easy to concentrate the streams