Part 10

Bureau of Chemistry and Soils H. G. Knight, Chief.

Bureau of Entomology C. L. Marlatt, Chief.

Bureau of Biological Survey Paul G. Redington, Chief.

Bureau of Public Roads Thomas H. MacDonald, Chief.

Bureau of Agricultural Economics Nils A. Olsen, Chief.

Bureau of Home Economics Louise Stanley, Chief.

Plant Quarantine and Control Lee A. Strong, Chief. Administration

Grain Futures Administration J. W. T. Duvel, Chief.

Food, Drug, and Insecticide Walter G. Campbell, Director of Administration Regulatory Work, in Charge.

Office of Experiment Stations --------, Chief.

Office of Cooperative Extension Work C. B. Smith, Chief.

Library Claribel R. Barnett, Librarian.

U. S. GOVERNMENT PRINTING OFFICE: 1930

For sale by the Superintendent of Documents, ---- Price 10 cents Washington, D. C.

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Transcriber Note

Minor typos have been corrected. Illustrations were moved to prevent splitting paragraphs. Figure 19 was moved adjacent to the directions and specifications on Page 24. Due to space considerations in the text only version, emphasis of column headers were sometimes eliminated and some of the tables were rearranged. Produced from files generously made available by USDA through The Internet Archive. All resultant materials are placed in the Public Domain.