00882cam a22002531 4500 agr35000214 DLC 20260227110954.0 750610s1935 xx 000 0 eng agr35000214 (OCoLC)1382744 DLC DSI OCoLC DLC premarc TL556 .U6 1935 United States. Department of Agriculture. Weather bureau. Aerological division. Instructions for airway meteorological service. Third edition. 1935. Washington, U.S. Govt. print. off., 1935. vi, 142 p. illus., diagrs. 24 cm. Circular N At head of title: U. S. Department of agriculture. Weather bureau. Earlier editions have title: Instructions for airway observers. Meteorology Observers' manuals. 9660 9660