Cyclopedia of applied electricity : a practical guide for electricians, mechanics, engineers, students, telegraph and telephone operators, and all others interested in electricity (1905)
American School (Chicago, Ill.) · Chicago : American School of Correspondence · leaf 423
THE NIAGARA TYPE OFPORCELAIN. INSULATOR, STRAIN INSULATOR FORDEAD ENDS AND CORNERS.
Electrical engineering
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.