Nepheloscope

{
  "id": "MLC-T-MET-007503",
  "term": "Nepheloscope",
  "field": "Meteorology and atmospheric science",
  "definition": "An apparatus devised by James Espy in the 1830s to study how clouds form, in which air in a vessel is suddenly expanded by releasing the pressure so that it cools. The size of the temperature fall is found from the pressure rise as the air warms back, and with moist air the cooling produces a visible cloud of droplets. It was an early cloud chamber.",
  "url": "https://mlchart.com/terminology/meteorology/nepheloscope/"
}