Titles read: "The Earthquake Spotter - A glance at the famous Ximenian Observatory, Florence."
Various shots of a man demonstrating how a seismograph works to record the position and extent of an earthquake. Highly sensitised paper, wound around a drum, is darkened with smoke black. Then a very fine glass point scrapes a line on the chart, according to the tremors felt through the earth. C/U of a finished chart.