Nikola Tesla U.S. Patent 1,061,142 - Fluid Propulsion Patent Wrapper Page 37

( C In considering this patent, the "duplex pumping wheel E" may be regarded as dissociated from the other portions of the device as it is the only part of the machine which, under any circumstances could be assumed to have a bearing on the claims herein. This pumping xhaxbex wheel constitutes merely a hollow. rotating chamber with an inlet port at its center and a continuous contracted peripheral slot, and when revolved at high speed, air or liquid contained in it or admitted to it is "ejected by centrifugal action through the circular nozzle £³". In other words, the Lundwall device is nothing more nor less than a modified form of the air pump of the Harris patent of record, and is intended, among other things, for the same purpose. (See page 3, lines 21-44) Whatever movement of air or fluid occurs in the Lundwall device is concentric, and not in natural spiral paths, because, by reason of its construction, the only effective action is centrifugal, and not in any appreciable sense, if at all, due to the adhesion of the air or fluid to the revolving walls of the chamber or to the resistance of the fluid to molecular displacement, - viscosity. Lundwall evidently had no conception of the possibility of the utilization of these properties of a fluid else he would not have constructed his device in the form of a hollow vessel or chamber with contracted outlet and in such manner as to preclude the flow of fluid in natural paths, and would not have obstructed the only path for the fluid by the braces which hold the two walls of the chamber together. It is evident at a glance that the path which the fluid follows in Lundwall is a forced and not a natural one. The combination claims, 5, 6 and 7, clearly distinguish -4This page retyped from microfilm for better readability - Ed.] 837