1st Experiment.
Experiments at Stokes Bay, England, 1873.—Countermine:—500 lbs. of gun-cotton, enclosed in a 3/16" iron case. It was placed on the ground, in 47' of water.
Submarine mines:—Six ground mines, 1/4" thick cases, fitted with circuit, 10' below the surface, at distances of 100' to 200' from the countermine.
Effect of explosion:—Submarine mines at 100' and 120' distance were destroyed, and their circuit closers thrown out of adjustment; submarine mines at 140' and 170' distance were much bulged, and leaked, and their circuit closer spindles were bent; submarine mine at 200' distance was uninjured, but its circuit closer was thrown out of adjustment.