Ingenious Sounding Apparatus

Rapid-test soundings were requirud in some work on a railway llce between Paris and Havre, where the cast iron viaduct of Bezous was replaced by an arch bridge alongside. The old foundations for six. channel piers were removed to the bottom of the river. It was required that the river bed should be carefully leveled. After it had been dredged the bottom was explored by means of a horizontal bar of iron about twenty feet long, which was suspended at each end from a framework uniting two flat boa ts in catamaran fashion. This beam was lowered close to the bottom and the boats were gradually moved ah.ng in the dlroction traneverse to the length of the bar. When the scraper encountered no lrregularity the suspending chains hung vertically, but as soon as edther end was deflected by contact with any obstruction an electric circuit was elosed, which caused an alarm to be rung. The boat was stopped and the obstruction located by means of sounding poles. In this way small stones down to a diameter of four inches were easily located and the bed of the river was leveled to within that amount of irregularity. This method proved rapid and