ABSTRACT
During the centuries that have elapsed since Heron’s time many attempts have been made to make a working machine out of this toy, some of which have been successful. The steam consumption can be brought down to that of a reciprocating engine of like power but it is still high, so that there is no incentive to follow up the idea. This pioneer machine was at once successful and proved to be an exception to the rule that an invention but rarely springs complete from a single brain, like Minerva from the head of Jupiter. In a reciprocating engine it is impossible to take advantage of a very high vacuum in the condenser, for we cannot have a cylinder big enough to expand the steam to a very low pressure, nor wide enough passages from the cylinder to the condenser to let the very low pressure steam out in time.
