In order to study the effectiveness of zinc for the cathodic protection of iron and steel under various soil conditions, zinc-iron couples were buried at eight test sites by the National Bureau of Standards in 1941. The galvanic currents produced by the couples and the potentials of the separate elements were measured when the couples were installed and as often thereafter as opportunity permitted. The couples have been removed from two of the sites, and it is planned to remove the remaining couples in the near future. Although the degree of protection afforded by coupling zinc to iron is definitely known at only two of the sites, it has been considered worthwhile to report at this time the behavior of the couples as indicated by the electrical measurements.
The design of the couples and their installation at the test sites were based on preliminary laboratory studies (1). Under...
