Eight-inch rain gauge
From AMS Glossary
eight-inch rain gauge
The rain drains into a collector tube that amplifies the depth by a factor of 10. The depth in the collector tube is measured by a wooden ruler. Formerly in common use in the United States.
NOAA/National Weather Service 1972. National Weather Service Observing Handbook No. 2, Substation Observations. NOAA, US GPO.