Garton-Daniels and Keystone lightning protective apparatus.
A 1921 trade catalogue issued by the Electric Service Supplies Co. of Philadelphia, presenting Garton-Daniels and Keystone lightning arresters for utility and building electrical engineers. The pictures show the arresters in grey-toned views, both as mounted metal panels and as enclosed weatherproof cases with hooded tops, with the sparking gaps, insulators and cylindrical coils clearly drawn. A designer could take from them a clear, schematic way of depicting industrial equipment, with tidy mounting plates, cast-metal hardware and neatly arranged component stacks.
