The story was about a robot/android made of brass and powered by air. His entire world, all the people in it, was built the same way.

He was fascinated by their brain analog which, by self-examination and experimentation, he discovers is a complex set of tiny, thin brass wafers with patterns on them that constantly moved and intermeshed due to air pressure.

All of the beings in this world needed to recharge their air pressure or they would die. The space below their world is a large pressurized air bladder that is slowing equalizing with the upper world.

  • Hi welcome to SF&F. When and where did you read this? "A while ago" isn't very precise, do you know approximately what years?
    – DavidW
    May 28 at 2:16
  • If memory serves, Corning developed glass circuits that operated on air pressure back in the 1950s in real life. The rival development of transistors stanched this technology, except for a few specialized glass products that could operate in the presence of strong magnetic fields. May 28 at 3:10

You may be thinking of Exhalation by Ted Chiang, as per Searching for a short story about metallic lungs:

Perhaps a few of us, in the days before we cease moving, will be able to connect our cerebral regulators directly to the dispensers in the filling stations, in effect replacing our lungs with the mighty lung of the world. If so, those few will be able to remain conscious right up to the final moments before all pressure is equalized. The last bit of air pressure left in our universe will be expended driving a person’s conscious thought.

And then, our universe will be in a state of absolute equilibrium. All life and thought will cease, and with them, time itself.

  • This was exactly it. Thank you for your help in finding it! May 28 at 11:39

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