Definition of pneumatic trough in English:

pneumatic trough

noun

Chemistry
  • A shallow liquid-filled container with which gases can be collected by displacing liquid from a jar inverted in the trough.

    • ‘The invention of the pneumatic trough, a device for collecting gases emanating from heated substances, by the English clergyman Stephen Hales in the early part of the century, was pivotal for bringing about this emphasis.’