Meter work of a municipal electricity supply system

(Member): Mr. Bernard mentions the use of sparks given out by an induction coil as a means other than ink for marking the paper in graphic instruments. Some years ago I was connected with the design of a recording compass in which this method was used, and from the brief experiments then carried out, I believe the use of the spark should be a satisfactory method of marking the paper and eliminating pen friction with the paper.