  A Szilard Engine is a hypothetical device which is able to extract work from
a single thermal reservoir by measuring the position of particles within the
engine. We derive the amount of work that can be extracted from such a device
in the low temperature limit. Interestingly, we show this work is determined by
the information gain of the initial measurement rather than by the number and
type of particles which constitute the working substance. Our work provides
another clear connection between information gain and extractable work in
thermodynamical processes.
