Nikola Tesla U.S. Patent 511,916 - Electric Generator Patent Wrapper Page 34

which of the two classes of ereine above described device of the Wood and Robinson patent belongs. have assumed from the start that engin es of the class of which this was cited as a type, that is, engines in which the pistons were free to move, were known at the date of the Jablochkoff patent and even earlier, so need not discuss the character of the reference in this respect. the -3But we that we While it is a fact, that both kinds of engine are old and well known, it is equally a fact that an engine which is constructed or designed for free movemen t under steam or air pressure, or in which in normal operation the piston is free to move under the action the reon of the steam, is a very rare exception, and no such engines are made unless specially designed for a definite object. To a hundred engines which are controlled, there is one which is free to move, and that one is constructed and designed for but one purpose. Therefore when Jablochkoff gives merely a convention al representation of a steam engine it is altogether probable that he had in mind the former and not the latter. It is furt her to be presumed that had he intended the latter, he would have called attention to at least some of the conditions to be expected in so radical a departure from usual methods. On the contrary he says, "In lieu of effect ing the production of current by the rotary movement of the bobbins etc." which necessarily implies a governor, or a ro41