2nd Experiment.
Countermine:—100 lbs. of gun-cotton enclosed in case, thickness No. 12 B. W. G. It was moored 10' below the surface, in 35' of water.
Submarine mines:—Five similar mines placed at same depth, at distances of 50' to 150' from the countermine.
Effect of explosion:—The submarine mine at 50' distance showed continued or dead earth, two screws broken, and its case dented; the other mines were uninjured.