Report issued by the U.S. Bureau of Mines discussing the electric smelting of nonferrous ores. As stated in the introduction, "it is the purpose of the present paper to survey the technical and economic changes that have taken place and to determine whether electric smelting of nonferrous ores offers any more promise today than 20 years ago" (p. 1). This report includes tables, and illustrations.

Volume provides a summary of the progress of each agricultural experiment station. Also includes statistics, a bibliography of experiment station publications, and selected studies.

This report gives a brief description of the present state of development and of the performance characteristics of instruments included in the following group: speed instruments, altitude instruments, navigation instruments, power-plant instruments, oxygen instruments, instruments for aerial photography, fog-flying instruments, general problems, summary of instrument and research problems. The items considered under performance include sensitivity, scale errors, effects of temperature and pressure, effects of acceleration and vibration, time lag, damping, leaks, elastic defects, and friction.