San Francisco: A fire alarm box.

The telegraphic fire alarm box operates separately from electric and telephone lines, and so is not affected by power outages, downed phone lines, bad mobile phone reception, or radio interference, making this piece of 19th century technology still valuable and relevant today.

Whenever the"Pull down hook" lever is pulled, a metal wheel inside the box turns and transmits a telegraphic signal to the Fire Department. All the boxes in a neighborhood or even a town are on the same circuit. When the box is triggered, the receiver at a fire station then can match the number to the neighborhood.