The paper deals with the surveying method in which direction, relative to points of the compass, is determined at the ground surface by observing the degree of rotation of a pipe which has an instrument rigidly attached to its lower end. This method is distinguished from those using some sort of compass within the instrument itself.

The practice of surveying bore holes will probably be increased within the oil industry. The object of the writer is to present data showing the degree of accuracy which may be expected. Specific description of instruments and details of their operation are not treated. Results of surveys made during the past twenty years in various lines of industry, aside from oil, are presented in such a manner as to indicate the degree of accuracy which has been obtained.

Theoretical considerations are mentioned but not discussed.

There is a description of a unique series of tests made at an oil well for the purpose of determining accuracy of several instruments and several methods. Maps and other data accompany the description.

There are brief descriptions of results and their meaning as obtained by means of duplicate surveys conducted at various oil wells in the course of regular industrial operations.

The conclusion of the writer is that the method under proper manipulation is amply accurate to meet the requirements of the oil industry.