Almost every suitable appliance known to physics has been proposed for the solution of the problem of submarine location and detection. As the submarine is a huge vessel built of metal, it might be supposed that such a contrivance as the Hughes induction balance might be employed to locate it. The Hughes balance is a device which is extremely sensitive to the presence of minute metallic masses in relatively close proximity to certain parts of the apparatus. Unfortunately, on account of the presence of the saline sea-water, the submersible is practically shielded by a conducting medium in [xxxvi]which are set up eddy currents. Although the sea-water may lack somewhat in conductivity, it compensates for this by its volume. For this reason, the induction balance has proved a failure.

But another method of detecting the position of a metallic mass is by the use of the . . . Read More