ScientificAmerican1917-06-09.jpg Scientific American 1916-10-28ThumbnailsScientific American 1916-10-28ThumbnailsScientific American 1916-10-28ThumbnailsScientific American 1916-10-28ThumbnailsScientific American 1916-10-28Thumbnails
Underground warfare: French sappers using the stethoscope to detect mining operations of the enemy.