Nikola Tesla U.S. Patent 1,061,142 - Fluid Propulsion Patent Wrapper Page 28

828 8161 In may also be pointed out that such a pump can be made without openings and spokes in the runner, as by using one or more solid dieks, each in its own casing, in which form the machine will be eminently adapted for sewage, drenging and the like, when the water is charged with foreign bodies and spokes or vanes especially objectionable. Another application of this principle which I have discovered to be not only feasible, but thoroughly practicable and efficient, is the utilization of machines such as above described for the compression or rarefaction of air, or gases in general. In such cases it will be found that most of the general considerations obtaining in the case of liquids, properly interpreted, hold true. when Then, irrespective of the character of the fluid, considerable pressures are desired, staging or compounding may be resorted to in the usual way the individual runners being, preferably, mounted on the same shaft. It should be added that the same end may be attained with one single runner by suitable deflection of the fluid through rotative or stationary passages. The principles underlying the invention are capable of embodiment also in that field of mechanical engineering which is concerned in the use of fluids as motive agents, for while in some respects the actions in the latter case are directly opposite to those met with in the propulsion of fluids, the fundamental laws applicable in the two cases are the same. In other words, the operation above described is reversible, for if water or air under pressure be admitted to the opening 11 the runner is set in rotation in the direction of the dotted arrow by reason of the peculier properties of the fluid which,