JF Ptak Science Books Quick Post
The photoelectric cell was a mature invention (appearing in 1883) when it became armed and lethal in 1930. Popular Mechanics published this photo (explained with only a caption and a paragraph) in its July 1930 issue. We see that should a prisoner make a dash up and over the prison wall, they interrupt the “electric eye” sentry which we read (1) fires a pistol positioned along the wall and (2) sounds an alarm, simultaneously. It seems as though the alarm system could be reconstituted at the base of the wall, sounding an alarm before the prisoner got to the wall (let alone up and over it), rather than shooting as the alarm sounds. The consequences of this idea–which I suspect was never implemented–were, well, rather extreme.
