A race of pneumatically-powered androids must come to terms with the fact that their very consciousness is built upon the variation in air pressure in their universe, and that the inevitable equilibrium of air pressure will mean the end of everything that they know.

This is a beautifully elegiac story that progresses from a clever solution to challenges of self-knowledge to acceptance of the inevitability of annihilation. The pneumatic society of the androids is tantalizingly sketched, and the problem of the equilibrium of air pressure is clearly a metaphor for the heat death of the universe or, much more urgently, climate change; for the former, the final acceptance is beautifully philosophical, but for the former a bit too sang-froid.