A technique used to locate features beneath the surface, such a buried chambers or ditches, by thumping the ground and sensing the differences between compacted and undisturbed earth. A resulting resonant sound may indicate a buried chamber or pit. It is an unsophisticated but effective method of searching for earthworks at archaeological sites, especially in chalk subsoil. Wooden mallets or lead-filled tools are examples of implements used. The verb 'bose' or 'bowse' means to test the ground for the presence of buried structures by noting the sound of percussion from a weighted striker.