Thuyer's Insulator

THUYER'S IMPROVED INSULATOR. — The body of the insulator is composed of a block of glass, protected by a bell-shaped casing of cast iron, through an opening in the top of which the glass projects; the casing being strongly cemented to the glass. To that portion of the glass projecting from the top of the casing is cemented a metal cap, from which projects three prongs, so arranged that the wire must be slightly bent in passing between them, it being thus prevented from slipping. The insulator is secured in its place by a pin, which projects from the pole into an opening in the underside of the glass. Both the cap and casing are thus so completely insulated that there can be no communication between the wire and the pole.