Nearly three hundred years ago John Battista Porta, a Neapolitan, made a hole in a wall in front of a dark room, and noticed that the rays entering, cast a shadow picture of the things outside. The hole was a projected eyeball, and the wall a choroid or curtain behind it. Gazing in wonder through this new order of eyeball, Battista Porta began to think of furnishing it, of putting something more behind it, and he put in—the first thing that he would have met if he had been examining his own eye—a lens! In that hour the long ages of free exercise closed. One eye-instrument maker after another appeared, and the eye unshrouded itself. One of the greatest was Galileo, a doctor, who was not only a great projector of the eye, but was the first projector of the pulse in the clock or timepiece.[1] "He took an old small organ pipe, jammed a spectacle-glass into either end, and behold! a magnifying glass!" Crowds
- ↑ In one of his books Oliver Lodge tells how Galileo, praying one day in the Cathedral like a good Catholic, as he was all his life, saw a great lamp swinging to and fro after the verger had lighted it; and how he (Galileo) began to time the swings by the only watch he possessed—his own pulse; how he noticed that the time of swing remained, as near as he could tell, the same, though the swings were getting smaller; and how he thus discovered the law on which the pendulum and all modern clocks are based. Galileo was at that time a doctor, and wanted to count people's pulses, and the pendulum served, just as watches (or pulsologies, as the first watches were called) still serve all doctors for the same purpose.
