ONE of the most interesting subjects dealt with at the recent Electrical Congress in Paris was earth currents. The absence of published information in France on the behaviour of these erratic disturbers of telegraphic peace has led to an elaborate and careful study of the whole question by M. Blavier, the well-known and distinguished director of the High School of Telegraphy of the Post and Telegraph Administration in France. This has been printed, published, and circulated by the Minister of Posts and Telegraphs (M. Cochery) for the use of the members of the recent Congress.
"Etude des Courants Telluriques," par E. E. Elavier . (Paris: Gauthier-Villars, 1884.)