Nikola Tesla U.S. Patent 1,119,732 - Apparatus for Transmitting Electrical Energy Patent Wrapper Page 13

T T 1 1 1 I The high tension wire 2 is fastened to the shell a³ as usual, care being taken, however, to establish a good electrical contact between both, as otherwise sparks will form, which may cause heating and damage. For the better understanding of the function of the device attention is called to the fact that the streamers, issuing from the wire, are apt to gradually heat the support and thus impair its insulating qualities or else, by slowly crawling over its surface, establish a good conducting path, permitting in either case the high pressure current to follow and to cause damage. But if in accordance with this invention, the insulator is provided with a conducting coating on the outside, such injurious action will be rendered impossible. This way of supporting high tension lines is both cheap and reliable. Obviously, in all cases, the insulating supports of the terminals, hoods or shells should be carefully protected from water. When practical conditions render it necessary to use a greater terminal capacity than can be conveniently obtained with one piece of metal, or with a smooth and unbroken surface, I either employ a numberor shells as a properly arranged, or I make up a terminal of a plurality of elements each having a sufficiently large radius or curvature. Such a construction is shown in Fig. 5, in which the terminal D consists of a suitably shaped metallic frame, in this case a ring of nearly circular cross section, which is covered with small half spherical metal plates 2, thus constituting a very large conducting surface, smooth on all places where the electric charge principally accumulates. 10 -5371709