Power Grid is Born The earliest electric lights are carbon arc lamps) top left), followed somewhat later by Edison's glow lamp (top right). At the same time, telephone service is just starting up in major cities, where central switchboards are needed to keep phone connections separate (bottom left).  Phone and power lines begin sprouting on poles in great clusters, cluttering downtown areas.

	Simple, but not obvious Unlike arc lamps, which are bright enough to be used as streetlights, Edison's first 'glow lamp' is so dim that it is often used in strings, to increase brightness. Edison isn't the first to make an electric light bulb, but his bulbs last longer than those of competitors. He uses a more durable filament, and a better system to create a vacuum in the bulb, which helps preserve the delicate filament (center bottom). This requires cutting the bulb, inserting the filament, and then re-fusing the glass (top right).
	Growing Tangle Phone service quickly gains popularity. Unlike electric lights, which can all share the same power line, telephones usually need a separate wire for each house or office. Telephone switchboards (top left) have a large array of sockets used to make connections between the wires attached to phones at each end of the call. Separate lines are impractical in rural areas, where many farms typically share the same line, called a party line. Anyone on a party line can listen to anyone else on the same line.