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.
1st Experiment.
Experiments at Carlscrona, Sweden, 1874.—Countermines:—226 lbs. of dynamite, enclosed in a case 17-1/2" × 20" × 1/8". It was moored 9-3/4' below the surface, the depth of water being 41 feet.
Submarine mines:—(a) cast iron ground 600 lb. mines, dome shaped, 48-3/4" × 21-1/2" × 2"; (b) cylindrical cases, wrought iron, empty, 11-1/2" × 11-1/2" × 1/8"; (c) cylindrical cases, wrought iron, charged, 11-1/2" × 11-1/2" × 1/8"; (d) cylindrical cases, wrought iron, 30-1/4" × 30-1/4" × 1/8"; (e) spherical cases, wrought iron, 32-1/2" × 1/8"; (f) spherical cases, tinned steel, 12" × 1/8".
Effect of explosion:—(b) mine, at 34' distance, was destroyed, and one at 92' distance was slightly bulged; (c) mine, 58' distance, mouthpiece injured and case leaky; (d) mine, 244' distance, a rivet started.
2nd Experiment.
Countermine:—As before, but moored at 29-1/4' below the surface; depth of water, 41 feet.