Abstract
The auther has devised the device for the measument of displacements in landslide mass by sensor pipes were inserted into the borehole like the spinal column. Sensor pipe was made up two short pipes which fastend stainless miniature rope respectively, and it led to the surface through in an outertube with togethe. And two stainless miniature ropes connected to a differential meter which moves differential prolongation of the two roper. The amount of sliding movement can be reded directly by the point of the differential meter, and the existence of one or more sliding surfaces can be distinguished. An example of observeition using it give forwing
