Nikola Tesla U.S. Patent 645,576 - System of Transmission of Electrical Energy Patent Wrapper Page 27

) ) ) J ) ( are obtained at say, 75 millimeters mercurial pressure, would be obtained at 150 millimeters with an increased electrical pressure. Now, for the currents of an ordinary induction coil of proper tension the air at 75 millimeters mercurial gauge is decidedly a conductor, while at 150 millimeters it is still a good insulator, behaving radically different, so that, even with a many times greater electrical pressure, the results obtained would be essentially different from those in the former case; for, in the latter instance, the air would simply break down as other insulating media do under the application of excessive electrical pressure. These differences in the behaviour of the air at various, and particularly, at greater mercurial pressures than those just referred to, are still more pronounced with currents such as are To illustrate, contemplated in my system of power transmission. the air at say, 100 millimeters mercurial gauge, while practically an insulator for currents of an ordinary transformer or induction coil, is a good conductor for the currents of extreme tension which I am producing. This fact, which I have well demonstrated, is one of the distinguishing features of my system and is clearly pointed out in my application. The Examiner requires that I should state the minimum height or atmospheric pressure at which my invention is designed to work. To limit me with a statement of this kind would be manifest(3) This page retyped from microfilm for better readability - Ed. 145