Maps. Atlas of American agriculture: Advance sheet 1, Precipitation, average annual precipitation in inches, based on records of about 1600 stations for 20-year period 1895-1914, and 2000 additional records, from 5 to 19 years in length, uniformly adjusted to same period; prepared by Joseph Burton Kincer. Scale 1:8,000,000. Geological Survey [Washington, D. C.]