Nikola Tesla - Free-Energy Devices

HIGH FREQUENCY AND HIGH POTENTIAL CURRENTS. 253In the course of these experiments a great many trials weremade with all kinds of carbon buttons. Electrodes made of ordinarycarbon buttons were decidedly more durable when thebuttons were obtained by the application of enormous pressure.Electrodes prepared by depositing carbon in well known waysdid not show up well ; they blackened the globe very quickly.From many experiences I conclude that lamp filaments obtainedin this manner can be advantageously used only with low potentialsand low frequency currents. Some kinds of carbon withstandso well that, in order to bring them to the point of fusion, it isnecessary to employ very small buttons. In this case the observationis rendered very difficult on account of the intense heatproduced. Nevertheless there can be no doubt that all kinds ofcarbon are fused under the molecular bombardment, but theliquid state must be one of great instability. Of all the bodiestried there were two which withstood best diamond and carborundum.These two showed up about equally, but the latterwas preferable for many reasons. As it is more than likely thatthis body is not yet generally known, I Avillattention to it.venture to call yourIt has been recently produced by Mr. E. G. Acheson, ofMonongahela City, Pa., II. S. A. It is intended to replace ordinarydiamond powder for polishing precious stones, etc., and Ihave been informed that itaccomplishes this object quite successfully.I do not know why the name " carborundum " hasbeen given to it, unless there issomething in the process of itsmanufacture which justifiesthis selection.Through the kindnessof the inventor, I obtained a short while ago some samples whichI desired to test in regard to their qualities of phosphorescenceand capability of withstanding high degrees of heat.Carborundum can be obtained in two forms in the form of"crystals" and of powder. The former appear to the naked eyedark colored, but are very brilliant the latter is of; nearly thesame color as ordinary diamond powder, but very much finer.When viewed under a microscope the samples of crystals givento me did not appear to have any definite form, but rather resembledpieces of broken up egg coal of fine quality. Themajority were opaque, but there were some which were transparentand colored. The crystals are a kind of carbon containingsome impurities;they are extremely hard, and withstand for along time even an oxygen blast. When the blast is directed