FIELD: physics.
SUBSTANCE: bottom reference mark consists of a solid, elongated, pointed rod with a stabiliser in form of resonant tuning-forks. At the end of the rod there is a sliding guide tube with holes and several cumulative charges inside. There is free space between the upper cumulative charge and the pointed end of the reference mark. At the base where the tuning forks are mounted, the rod is in form of an acute angle prism.
EFFECT: design of a reference mark which is lowered to the bottom, composed of blocks of rocks of any hardness, including metal surface.
3 cl, 2 dwg
