Armature windings of direct-current dynamos: Extension and application of a general winding rule. By E. Arnold, Engineer and Assistant Professor in Electrotechnics and Machine Design at the Riga Polytechnic School. Translated from the original German by Francis B. De Gress, M.E., Chief of Testing Department, Crocker-Wheeler Company. With 146 illustrations. 8vo., pp. vi + 124. New York: D. Van Nostrand Company. 1902. (Price, $2)