Electrical instruments for determining the moisture, temperature, and soluble salt content of soils
A USDA Bureau of Soils technical bulletin by Lyman J. Briggs, printed by the Government Printing Office in Washington in 1899 for field scientists measuring soil moisture, temperature, and salts. Pen-and-ink plates signed W. R. Scholl show wooden instrument cases, coiled cords, wire splices, and labeled circuit diagrams, offering fine hatched wood grain, dial faces, and schematic line work.
